Myles Taylor BA MRCOG PhD

The counselor explains inheritance patterns pregnancy ovulation calculator generic ardomon 50 mg overnight delivery, assesses risks for specific individuals in a family womens health editor generic 25 mg ardomon otc, recommends tests menstruation chart order 25 mg ardomon fast delivery, and interprets the results of tests women's health center ventura order ardomon 100 mg online. They may specialize in prenatal care or work in clinics for patients with specific diseases breast cancer freebies buy ardomon 100 mg with amex, such as familial cancers, hereditary forms of blindness, or inherited blood disorders. Genetic counselors are hired to help in the ongoing effort to identify the functions of all of the genes in the human genome, a process called annotation. This entails searching disease and mutation databases and reading the scientific and medical literature to connect reports and information to Dna sequences. Genetic counselors are at the forefront of making practical sense of the human genome sequences. Discovering how diseases are related at the genetic level is enabling physicians to "repurpose" existing drugs. This is the case for progeria, an inherited disease that causes a young child to show signs of greatly accelerated aging. Teeth never erupt, joints stiffen and bones weaken, and the skin wrinkles and toughens. Blood vessels stiffen with premature atherosclerosis, fat pockets shrink, and connective tissue hardens. When researchers in 2003 identified the mutant gene, they realized, from the nature of the molecular defect, that several existing drugs might alleviate certain symptoms. They tested a failed cancer drug, and several children began to gain weight, and their arteries grew less stiff as the blockages shrunk. The drug that helps children with progeria is now being tested in people who develop atherosclerosis as part of aging. The sticky secretions impair breathing and increase the risk of certain respiratory infections. Collins, "Reverse Genetics and Cystic fibrosis," in American Journal of Respiratory Cellular and Molecular Biology, 2:309­316 (1990). Knowing how genes are distributed in meiosis and the combinations in which they can join at fertilization makes it possible to calculate the probability that a certain trait will appear in the offspring of two particular individuals. The patterns in which genes are transmitted in families are termed modes of inheritance. An educator, monk, and gardener named Gregor Mendel deciphered the modes of inheritance in the 1860s by breeding pea plants and following easily visible traits over several generations. The laws he derived apply to humans because our cells are diploid, like those of peas and most other multicellular organisms. Pairs 1 through 22 are autosomes (awto-somz), which do not carry genes ¯ that determine sex. The other two chromosomes, the X and the Y, include genes that determine sex and are called sex chromosomes. A human somatic cell has two copies of each chromosome, and therefore two copies of each gene. For genes with only two alleles, the dominant ones are usually indicated with a capital letter. It may also be autosomal (carried on a nonsex chromosome) or X-linked (carried on the X chromosome) or Y-linked (carried on the Y chromosome). The mode of inheritance refers to whether a trait is dominant or recessive, autosomal or carried on a sex chromosome. This designation has important consequences in predicting the chance that offspring will inherit an illness or trait. A person most likely inherits a recessive condition from two parents who are heterozygotes (carriers). If, by chance, a dominant trait does not appear in a generation in a particular family, it does not reappear in subsequent generations, as a recessive trait might. Certain recessive mutant alleles disrupt the structure and/or function of the chloride channels. A person inheriting one recessive mutant allele plus a dominant wild type allele is a carrier and transmits the disease-causing allele in half of the gametes. The three possible genotypes are associated with only two phenotypes, because carriers and homozygous dominant individuals do not have the illness. A person who has two different mutant alleles is called a compound heterozygote, and may or may not have symptoms, depending upon the effects of the allele combination on the chloride channels. A person who has two identical alleles of a particular gene is homozygous (homo-zigus) for that gene. A person with two different alleles for a gene is heterozygous (heter-o-zigus) for it. A gene may have multiple alleles, but an individual person can normally have a maximum of two alleles for a particular gene. The allele that causes most cases of cystic fibrosis was discovered in 1989, and a test was developed to detect it. Different allele combinations produce different combinations and severities of symptoms. That is, all humans have the same types of genes, but differ in the specific variants. The appearance or health condition of the individual that develops as a result of the ways the genes are expressed is the phenotype (feno-ti p). An allele is wild type if its associated phenotype is either normal function or the most common expression in a particular population. A Punnett square is a table that symbolizes the logic used to deduce the probabilities of genotypes in offspring. Circles are females and squares are males; shaded-in symbols represent people who have a trait or condition; half-shaded symbols denote carriers. A person who has an autosomal recessive illness has parents who are carriers-they do not have the illness. Or, if the phenotype is mild, a parent might be homozygous recessive and affected. A person who has an autosomal dominant condition typically has an affected parent, and need inherit only one copy of the mutant allele to have the associated phenotype. In contrast, expression of an autosomal recessive condition requires inheriting two mutant alleles. Carriers for sickle cell disease and certain other inherited anemias do not easily contract malaria. Symptoms usually begin in the late thirties or early forties and include loss of coordination, uncontrollable dancelike movements, behavioral changes, and cognitive decline. Assuming the other parent does not have a mutant allele, each child conceived has a 1 in 2 chance of inheriting the disease allele and, eventually, developing the condition. Symbols in the pedigree with both black and white indicate unaffected carriers (heterozygotes). For some autosomal dominant disorders, genetic tests can reveal that a disease-causing genotype has been inherited, even before symptoms begin. In incomplete dominance, the heterozygous phenotype is intermediate between that of either homozygote. A person with one disease-causing allele (a heterozygote) has half the normal number of cholesterol receptors. The associated phenotypes parallel the number of receptors-those with two mutant alleles develop severe disease as children, individuals with one mutant allele may become ill in young or middle adulthood, and people with two wild type alleles do not develop this type of hereditary heart disease. The I gene encodes the enzymes that place the A and B antigens on red blood cell surfaces. The pedigree symbols for hD are completely filled in to indicate that the person is affected. Children with unusual sets of symptoms have their exomes sequenced to identify mutations. Genetic tests can indicate which drugs are most likely to be effective in particular patients. This condition increases serum cholesterol level in the blood, raising the risk of developing cardiovascular disease. The photograph shows cholesterol deposits near the eyes of a person who is a homozygote for the disease-causing allele. Pleiotropy is seen in genetic diseases that affect a single protein found in different parts of the body. This is the case for Marfan syndrome, an autosomal dominant defect in an elastic connective tissue protein called fibrillin. The most serious symptom is weakening in the aorta wall, which can burst the vessel. Genetic Heterogeneity the same phenotype resulting from the actions of different genes is called genetic heterogeneity (je-netik heter-o-je-nei-te). For example, the nearly 200 forms of hereditary deafness are each due to impaired actions of a different gene. Genetic heterogeneity occurs when genes encode different enzymes that catalyze the same biochemical pathway, or encode different proteins that are part of the pathway. Clotting disorders may result from mutations in the genes that specify any of the enzymes that catalyze these reactions, leading to several types of bleeding disorders. The terms penetrance, expressivity, and pleiotropy are used to describe some of these distinctions of genotype expression. Penetrance and Expressivity Penetrance refers to the all-or-none expression of a genotype in an individual, whereas expressivity refers to degrees of a phenotype. Some disease-causing allele combinations are completely penetrant, which means that everyone who inherits a particular genotype expresses the associated phenotype. A genotype is incompletely penetrant if some individuals do not express the associated phenotype. Some people who inherit the autosomal dominant allele have more than five digits on a hand or foot, yet others known to have the allele (because they have an affected parent and child) have ten fingers and ten toes. If 80 of 100 people who have inherited the dominant polydactyly allele have extra digits, the allele is 80% penetrant. For example, a person who inherits a genotype that increases the risk of lung cancer many not develop the cancer if the lungs remain free of smoke and pollution. A phenotype is variably expressive if the manifestation varies in intensity in different people-which is nearly always the case. One person with polydactyly might have an extra digit on both hands and a foot; another might have two extra digits on both hands and both feet; a third person might have just one extra fingertip. Tests for the gene known to cause osteogenesis imperfecta, "brittle bone disease," which can break bones even in a fetus (see fig. Characteristics molded by one or more genes plus the environment are termed multifactorial traits. Pleiotropy A single gene that effects several phenotypic traits exhibits pleiotropy (pleot-ro-pe). Family members who have different sets of symptoms can appear to have different illnesses, when they actually have the same pleiotropic disorder. A polygenic trait, with many degrees of expression because of the input of several genes, is said to be continuously varying. Although the expression of a polygenic trait is continuous, we can categorize individuals into classes and calculate the frequencies of the classes. When we do this and plot the frequency for each phenotype class, a bell-shaped curve results. This curve indicating continuous variation of a polygenic trait is strikingly similar for different characteristics, such as fingerprint patterns, height, eye color, and skin color. Even when different numbers of genes contribute to the phenotype, the curve is the same shape. The colored part of the eye, the iris, darkens as melanocytes produce the pigment melanin. Unlike melanin in skin melanocytes, the pigment in the eye tends to stay in the cell that produces it. Blue eyes have just enough melanin to make the color opaque, and dark blue or green, brown or black eyes have increasingly more melanin in the iris. If each dominant allele contributes a certain amount of pigment, then the greater the number of such alleles, the darker the eye color. The bell curve arises because there are more ways to inherit light brown eyes, with any two dominant alleles, than there are ways to inherit the other colors. Other genes modify the expression of the two genes that control melanin synthesis. Overlying the colors and tones are specks and flecks, streaks and rings, and regions of dark versus light that arise from the way pigment is laid down onto the distinctive peaks and valleys at the back of the iris. Height and skin color are multifactorial as well as polygenic, because environmental factors influence them: good nutrition enables a person to reach the height dictated by genes, and sun exposure affects skin color. Most of the more common illnesses, including heart disease, diabetes mellitus, hypertension, and cancers, are multifactorial. These students in a genetics class lined up by height to illustrate the continuously varying nature of the trait. Sex is determined at conception: a Y-bearing sperm fertilizing an egg conceives a male, and an X-bearing sperm conceives a female (fig. The female is termed the homogametic sex because she has two of the same type of sex chromosome, and the human male is called the heterogametic sex because his two sex chromosomes are different. Genes on the Sex chromosomes Genes that are part of the X and Y chromosomes are inherited in different patterns than are genes on the autosomes because of the different sex chromosome constitutions of males and females. Traits transmitted on the X chromosome are X-linked, and those transmitted on the Y chromosome are Y-linked. The X chromosome has more than 1,500 genes; the Y chromosome has only 231 protein-encoding genes. Y-linked genes are considered in three groups, based on their similarity to X-linked genes.

At the lateral end menstruation bowel movements purchase online ardomon, it is separated from the glenoid cavity by the root of the coracoid process breast cancer wallpaper discount 100 mg ardomon free shipping. A deep suprascapular notch (also called the scapular notch) is seen close to the lateral end of the superior border the medial border menopause stages best purchase ardomon, otherwise called the vertebral border women's health group york pa cheap ardomon 100 mg line, extends from the superior to the inferior angle pregnancy for dads order ardomon overnight delivery. It is arched and thicker than the superior border, because it gives attachments to muscles. It forms a projection that is directed forwards and partly overhangs the glenoid cavity. It has lateral and medial borders which meet anteriorly at the tip of the acromion. The lateral border meets the crest of the spine at a sharp angle (usually a right angle) as termed the acromial angle. The medial border shows the presence of a small oval facet for articulation with the lateral end of the clavicle. The acromion also has upper and lower surfaces; the lateral border of the spine fades into the lower surface. The root of this process is attached to the body of the scapula just above the glenoid cavity. The tip portion which is also called the horizontal part is directed forwards, laterally and a little downwards. Its anterior margin is grooved by the subscapularis tendon and so the glenoid gets a pear shape Just below the cavity, the lateral border shows a rough raised area called the infraglenoid tubercle. Immediately above the glenoid cavity is a rough area ca led the supraglenoid tubercle. The part of the body adjoining the lateral border is thickened to form a longitudinal bar of bone, called the strengthening bar. The spinous process is a large triangular projection from the posterior surface of the body. The apex of the triangle is at the medial end, and the base is laterally placed and forms the lateral border of the spine. The anterior border of the spine is attached to the dorsal surface; the posterior border is free and is greatly thickened to form the crest of the spine. The medial end of the spine (apex) lies near the medial border of the scapula and is often referred to as the root of the spine. The crest is broad and flat; it has upper and lower lips with the intervening area being subcutaneous. The next two or three digitations are inserted into a narrow line along the medial border. The lower 4 or 5 digitations are inserted into a large triangular area over the inferior angle. The inferior belly of the omohyoid arises from the upper border near the suprascapular notch. The subscapularis arises from the whole of the costal surface, except for a small part near the neck. The teres major arises from the lower one-third of the rough strip extending over the inferior angle. The supraspinatus arises from the medial two-thirds of the supraspinous fossa, including the upper surface of the spine. The infraspinatus arises from the greater part of the infraspinous fossa, except near the lateral border and a part near the neck. Vertebral levels: Different parts of the scapula correspond to different vertebral levels and these can be used as landmarks the superior angle corresponds to T2 spine, the root of spine to T3 spine and the inferior angle to T7 spine. The medial border of this triangle is the lateral border of trapezius, the lateral border is the lower part of the medial border of scapula and the inferior border is the upper line of latissimus dorsi. The suprascapular vessels and nerve are related to the superior border and the spinoglenoid area. The circumflex scapular branch of the subscapular artery turns around the lateral border between the two sets of fibres of teres minor and reaches the posterior aspect. The deep branch of the transverse cervical artery is related to the medial border. The suprascapular nerve can be entrapped at the suprascapular foramen or the spinoglenoid foramen. Usual sites of fracture are: Body of the scapula Fracture through the neck Fracture of the acromion process Fracture of the coracoid process. Winging of the scapula: (also called scapula alata) is a condition in which the medial border of the scapula is lifted off the chest wall. In the upper part of glenoid cavity, the attachment of the capsule extends above the supraglenoid tubercle which makes the origin of the long head of the biceps intracapsular, i. The suprascapular ligament (also called the superior transverse ligament) bridges across the suprascapular notch and converts it into a foramen which transmits the suprascapular nerve. The spinoglenoid notch is often converted into a foramen by the spinoglenoid ligament. The suprascapular nerve and artery enter the infraspinous fossa from the supraspinous fossa through the spinoglenoid notch or the foramen, if present. The rhomboideus major is inserted from the root of the spine to the inferior angle. The latissimus dorsi receives a small slip from the dorsal surface of the inferior angle. The meeting point of the apex of the spine and the medial border of scapula has a small triangular smooth area which is covered by the fibres of trapezius muscle. The same smooth triangle can be readily felt at the level of T3 spine and is used as a landmark. The acromial angle is also felt easily and used as a measuring point for chest dimensions. In some cases, the acromion is attached to the spine by cartilage or by a synovial joint (spinoacromial joint). Some authors define a primary centre for the coracoid process because of the appearance of such a centre before birth. The bony parts of scapula may get absorbed in old age with only the periosteum remaining. The crest of the spine is clinically referred to as the posterior border of the bone. The medial most point of attachment of deltoid fibres on the lower lip of the crest is prominent and is referred to as the deltoid tubercle When the scapular body is in anatomical position, the medial border runs parallel and about 5 cm lateral to the thoracic vertebrae. The greater part of the coracoid process is ossified from a secondary centre that appears in the first year. The remaining secondary centres, which appear about the age of puberty, are one for the subcoracoid area including the glenoid, two for the acromion, one for the medial border and one for the inferior angle. This is a physiological joint where movements occur between, on one side, the scapula and the associated muscles and, on the other, the thoracic wall this is not an anatomical joint where movements occur between bony elements. The scapulothoracic joint is where the movements of scapular elevation-depression, scapular protractionretraction and scapular rotation occur. The lower end is expanded the head is directed medially and so helps to decide the medial and lateral sides the anterior aspect of the upper end shows a prominent vertical groove called the intertubercular sulcus. From the above-mentioned information, the side of a given humerus can be determined. The head is rounded (actually forms a third of a sphere) and has a smooth convex articular surface. The articular surface articulates with the glenoid cavity of the scapula to form the shoulder joint. It may be noted that the articular area of the head is much greater than that of the glenoid cavity. There are two distinct regions of the upper end of the humerus which are referred to as the neck. The three borders are called the (1) anterior, (2) medial and (3) lateral borders. When traced upwards, the anterior border becomes continuous with the anterior margin of the greater tubercle (or crest of the greater tubercle, or lateral lip of the intertubercular sulcus). The medial border is indistinct, but can be traced to the lower end of m co sf re. This is the region that narrows down from the head and the tubercles to join the shaft. Apart from these two, the line corresponding to the junction of epiphysis and metaphysis is called the morphological neck. The two prominences in the upper end are called the greater and lesser tubercles (or tuberosities). These two tubercles are separated by the deep groove called the intertubercular sulcus (also called the bicipital groove) which is seen as a vertical furrow on the anterior aspect of the upper end. The uppermost of these is on the superior aspect, the lowest on the posterior aspect, and the middle is in between them. The lesser tubercle is on the anterior aspect of the bone medial to the intertubercular sulcus and lateral to the head. The intertubercular sulcus lies between the two tubercles and passes down to the shaft. The anterior part of the greater tubercle continues down as the crest of the greater tubercle and forms the lateral lip of the sulcus. The medial part of the lesser tubercle continues down as the crest of the lesser tubercle and forms the medial lip of the sulcus. The lower part of the lateral border can be seen from the front, but its upper part runs upwards on the posterior aspect of the bone. The three borders of shaft divide it into three surfaces, namely the anterolateral, anteromedial and posterior surfaces. The anterolateral surface lies between the anterior and lateral borders the anteromedial surface lies between the anterior and medial borders the posterior surface lies between the medial and lateral borders In the anterolateral surface, a V-shaped rough area called the deltoid tuberosity is present near the middle. The anterior limb of the tuberosity lies along the anterior border of the shaft while the posterior limb lies above the lower part of the radial groove. When the shaft is observed from behind, a broad and shallow groove called the radial groove (also called the spiral groove, since it appears to spiral around the shaft) running downwards and laterally across the upper parts of the posterior and anterolateral surfaces can be seen. The part of the lateral border below the groove is indistinct, but the part of the border above the groove can be traced to the posterior part of the greater tuberosity. The upper margin of the radial groove is formed by a roughened ridge that runs obliquely across the shaft. The lower end of the ridge is continuous with the posterior limb of the deltoid tuberosity. The shaft between the radial groove and the lower end of the bone widens out below and is smooth. It is flattened from backwards, expanded from side to side and bent slightly forwards. It has articular and non-articular parts As the lower end expands both medially and laterally, the prominences made out of such expansions form the medial and the lateral epicondyles. The middle portion of the distal edge of the bone can be seen to be pulley-shaped and is called the trochlea. Lateral to the trochlea is the rounded convex projection called the capitulum (Latin. The capitulum can be seen on the anterior and inferior aspects of the bone but does not extend posteriorly. The bone above the trochlea is thinned out and so depressions can be seen both on the anterior and posterior aspects. The medial margin of the trochlea projects downwards much below the level of the capitulum, and of the epicondyles. The lowest parts of the medial and lateral borders of the humerus form sharp ridges called the medial and lateral supracondylar ridges. The posterior aspect of the lateral epicondyle is smooth and subcutaneous and, therefore, is felt easily. The pectoralis major is inserted into the lateral tip of the intertubercular sulcus. On the medial side, the line of attachment dips down by about a centimetre to include a small area of the shaft within the joint cavity. The line of attachment of the capsule is interrupted at the intertubercular sulcus to provide an aperture through which the tendon of the long head of the biceps leaves the joint cavity. The capsular ligament of the elbow joint is attached to the lower end of the bone. Anteriorly the line of attachment reaches the upper limits of the radial fossa and the coronoid fossa. The medial and lateral epicondyles give attachment to the ulnar and radial collateral ligaments respectively. The pronator teres (humeral head) arises from the anteromedial surface, near the lower end of the medial supracondylar ridge. The brachioradialis arises from the upper two-thirds of the lateral supracondylar ridge. The extensor carpi radialis longus arises from the lower one-third of the lateral supracondylar ridge. The superficial flexor muscles of the forearm arise from the anterior aspect of the medial epicondyle. The common extensor origin for the superficial extensor muscles of the forearm is located on the anterior aspect of the lateral condyle. The lateral head of the triceps arises from the oblique ridge on the upper part of the posterior surface, just above the radial groove. The medial head of the muscle arises from the posterior surface below the radial groove.

The intermediate compartment lying deep to the palmar aponeurosis breast cancer 5k 2014 generic 25 mg ardomon with mastercard, is bounded medially and laterally by the corresponding palmar septa women's health center glens falls ny discount ardomon american express. It contains the tendons of the flexor digitorum superficialis womens health zeeland buy ardomon 100 mg lowest price, flexor digitorum profundus and flexor pollicis longus menstrual cramps 9dpo 50 mg ardomon purchase fast delivery, the lumbrical muscles menstruation yahoo health ardomon 50 mg buy cheap, the superficial palmar arch and its digital branches, the deep palmar arch and the digital branches of the median and ulnar nerves. The intermediate compartment is further subdivided into two parts by an intermediate palmar septum (also called the oblique palmar septum; clinicians call it the lateral fibrous septum). This septum passes from the deep surface of the lateral part of the palmar aponeurosis to the front of the third metacarpal bone. The lateral part of the intermediate compartment that lies between the lateral and the intermediate palmar septa is the thenar space (space and not compartment; there is another thenar compartment). The medial part of the intermediate compartment that lies between the intermediate and the medial palmar septa is the midpalmar space. In that case, the second lumbrical muscle and its lumbrical canal are related to the thenar space and not to the midpalmar space. Relationship to the ulnar and radial bursae: the long flexor tendons to the medial four fingers form the anterior limits of the thenar and midpalmar spaces. Therefore, the ulnar bursa (common synovial sheath) is intimately related to both the spaces. The radial bursa (synovial sheath of the flexor pollicis longus tendon) is on the lateral aspect of the thenar space and still closely related. Clinical Correlation Infections in the region of the fingertips are commonly caused by pinpricks or cuts. Such infections cause much pain because the region of the tip of the finger is divided into a number of small compartments and distension of any compartment with pus presses on nerve endings there. In such a case, the distal portion of the terminal phalanx suffers avascular necrosis Drainage of pus should be done through the point of maximum tenderness; drainage prevents complications. The midpalmar space sometimes may communicate with this space under cover of the flexor retinaculum. As already seen, the ulnar and the radial bursa extend about 2 cm proximal to the flexor retinaculum. The space is drained through incisions along the lateral and medial borders of the lower part of the forearm. Each web space extends from the free margin of the skin fold to the level of the metacarpophalangeal joints. Subcutaneous fat, superficial transverse metacarpal ligament, tendons of corresponding lumbricals and interosseous muscles and digital vessels and nerves are the contents of the web spaces. There are two spaces on the dorsum of the hand which are occasionally sites of infection. The subcutaneous space lies immediately under the skin and superficial to the fascia over the extensor tendons. Infections from the digits and palm can travel to these spaces through lymphatics. Similarly, tenosynovitis of the thumb can infect the radial bursa because of the continuity of the tendon sheaths. Inflamed ulnar bursa can burst into the midpalmar space and inflamed radial bursa can burst into the thenar space resulting in abscesses in these spaces. The dorsolateral cells of the concerned somites migrate into the buds and form a muscle tissue mass. With further elongation of the limb buds, the muscle mass splits into two: the ventral flexor mass and the dorsal extensor mass. However, each of these masses splits and fuses again and again such that a single muscle of the limb may be formed from components of more than one original muscle piece. Subsequently, the ventral divisions of all the rami join together and the doral divisions also do so. The radial nerve is derived from the dorsal divisions and so supplies the dorsal extensor musculature. The median and the ulnar nerves are derived from the ventral divisions and so supply the ventral flexor musculature. The contact between the nerves which penetrate into the limb buds and the mesenchyme of the buds is established quite early in development. This contact acts as a stimulus for complete functional differentiation of the muscles. The boundaries of a pulp space are: Proximally: Fusion of fibrous flexor sheath of the digit to the periosteum of the terminal phalanx posteriorly and to the skin at the distal digital crease anteriorly; Distally: Tip of the digit; At the Sides: Fusion of the deep fascia to the periosteum on the sides of the terminal phalanx. The pulp space contains a number of septa which pass from the skin to the periosteum. Before the digital artery enters the pulp space, it gives off an epiphyseal branch that supplies the basal portion of the terminal phalanx. The diaphyseal branches arise within the space and enter into the shaft portion of the bone. The operating distance of long flexors is increased c the wrist flexors counteract the finger extensors d. It is a complex movement that involves both the carpometacarpal and the metacarpophalangeal joints of the thumb b. Cupping of the palm is a prerequisite for better opposition c Opponens pollicis contributes only to a part of the entire range of opposition d. When he returned after a week, he complained of sensory loss in both his hands, but more on the right side. The girdle itself articulates with the axial skeleton through the sternoclavicular joint. Thus the clavicle directly articulates with the axial skeleton but the scapula does not. The human body, during the process of evolution, had undergone modifications to adapt to a skilled style of life. The joints of the upper limb have, therefore, been provided with more mobility than stability. The cavity of the joint is often partially subdivided by a wedge shaped articular disc. The capsule is thickened on its upper part and is reinforced by the acromioclavicular ligament and fibres of trapezius (F gs 18. Both facets are covered with articular cartilage and both slope downwards and medially. Discuss the elbow joint with relation to its fibrous capsule, ligaments, synovial membrane, relations and movements Discuss the radiocarpal joint with relation to its fibrous capsule ligaments, synovial membrane, relations and movements. Discuss the midcarpal joint with relation to its fibrous capsule, ligaments, synovial membrane, relations and movements. Discuss the carpometacarpal joint of the thumb with relation to its fibrous capsule, ligaments, synovial membrane, relations and movements. Write notes on (a) Sternoclavicular joint, (b) Acromioclavicular joint, (c) Glenohumeral ligaments, (d) Rotator cuff, (e) Coracoacromial arch, (f) Ulnar collateral ligament of elbow, (g) Glenoidal labrum, (h) Scapula and its influence on the shoulder joint, (i) Scapulohumeral rhythm, (j) Carrying angle, (k) Annular ligament, (l) Factors contributing to the stability of the shoulder, (m) Bursae around the shoulder, (n) Abduction and elevation of arm, (o) Movements of thumb, (p) Opposition movement, (q) Abduction­adduction of fingers, (r) Writing position, (s) Interosseous membrane of upper limb. The clavicle, takes upon itself the responsibility of keeping the upper limb clear of the trunk to enable smooth functioning of the limb without any impingement or obstruction. The forearm has a special set of movements, namely pronation and supination, which enhances the skill of the upper limb. The hand (along with the fingers) is anatomically designed for intricate movements and coordination. The ligament consists of two parts, so named because of their shape: (1) trapezoid and (2) conoid. The trapezoid part is attached, below, to the superior surface of the coracoid process; and, above, to the trapezoid line on the inferior surface of the lateral part of the clavicle; the attachments are slightly askew so that this part lies more or less horizontal. The conoid part is attached, below, to the root of the coracoid process just lateral to the scapular notch and above, to the inferior surface of the clavicle on the conoid tubercle; the coracoid attachment is the apex and the clavicular attachment the base of the cone. The two parts are continuous posteriorly but are separated anteriorly by an interval that is usually occupied by a bursa. The joint is supplied by branches of adjacent arteries and by twigs of lateral pectoral, suprascapular and axillary nerves. It is an extracapsular accessory ligament of the joint and extends from the superior surface of coracoid to the inferior surface of clavicle. To study the acromioclavicular joint, clean the superior and inferior ligaments first. Open the joint, clean and define the coracoacromial and coracoclavicular ligaments. To study the sternoclavicular joint, detach the sterna head of the sternocleidomastoid first. Identify the short and long heads of biceps, coracobrachialis and the joint capsule. Turning the cadaver around, make a vertical incision in the posterior part of the joint capsule. If the arm is now rotated medially, the glenohumeral l gaments can be seen clearly. These movements are necessary for allowing various movements of the scapula associated with movements of the arm at the shoulder joint. Vertical movement of the scapula on the chest wall, gliding forward and backward of the scapula on the clavicle and free elevation of the free upper limb are possible by movements occurring at the acromioclavicular joint. The two parts of the coracoclavicular ligament play an important role in stabilising the clavicle in particular and the shoulder region in general. The conoid part prevents backward movement of the lateral part of the clavicle without any similar movement of the scapula; the trapezoid part prevents any such forward movement. Both of them together prevent the acromion being carried medially below the clavicle when blows or forces fall on the lateral aspect of shoulder. Severe blows to the curve of the shoulder may tear the coracoclavicular ligament and push the acromion beneath the clavicle. Once the humerus is separated off, study the glenoidal labrum and the other relations of the joint. The articular surfaces are concavo-convex; that on the clavicle being convex vertically and concave horizontally. The articular surface of the clavicle is also slightly larger so that the medial end of clavicle projects above the manubrium sterni. A fibrocartilaginous articular disc divides the joint cavity; it is fused to the internal aspect of the capsule both in front and behind; it is also attached, above to the clavicle and below to the first costal cartilage. The thickened bands of the capsule in front and behind are called the anterior and posterior sternoclavicular co ee. Both these ligaments pass downwards and medially from the clavicle to the sternum; the anterior ligament is stronger than the posterior. The interclavicular ligament passes between the sternal ends of the right and left clavicles, some of its fibres being attached to the upper border of the manubrium sterni; it is actually a continuation of the condensation of the joint capsule on the superior aspect. The costoclavicular ligament is an extracapsular ligament, situated a little away on the lateral side of the joint. The joint is supplied by branches of adjacent arteries and by twigs of medial supraclavicular nerve and nerve to subclavius. Maximal movement is possible in the coronal plane but both anteroposterior movements and rotational movements around the long axis also occur. Forward and backward movement of clavicle occurs in the medial compartment; elevation and depression of clavicle in the lateral compartment. The muscles responsible are as follows: Forward movement Backward movement Elevation Serratus anterior Trapezius and rhomboids Trapezius, sternocleidomastoid, levator scapulae and rhomboids Pectoralis minor and subclavius fre e Depression oo om k Table 18. When there is any violent force, the bone usually fractures and the joint is spared. In dislocations of the sternoclavicular joint the medial end of the clavicle is usually displaced forwards. Backward dislocation is much more serious as the bone may press on the trachea or one of the large vessels at the root of the neck. However, the girdle movements set stage for proper, effective and efficient shoulder movements. Movements at the shoulder girdle occur not only in the two constituent articulations of acromioclavicular and sternoclavicular joints but also in the functional scapulothoracic joint. Forward movement of scapula along the thoracic wall causes the glenoid cavity to face forwards; backward movement causes the glenoid to face more laterally. Upward movement of scapula along with a rotation that causes the inferior angle to move superoanteriorly makes the glenoid cavity face upwards. Downward slide of scapula along with a rotation that causes the inferior angle to move medially makes the glenoid turn a little downwards. However, the actual execution of these movements requires action at the other joints. The clavicle acts as a strut and by providing thrust at the acromioclavicular joint, keeps the scapular glenoid in such a way that the latter is free for varied movements. If the glenoid and the lateral angle of scapula have to maintain this freedom, they have to remain clear of the trunk and travel along the arc of a circle whose radius is the clavicle. On the contrary, the medial aspect of the scapular blade is held close to the thoracic wall and can only travel along the arc of a smaller circle and radius, namely, the thoracic wall curve. It is not possible for the scapular blade to travel through wider or larger arcs and circles. However, in order to retain the freedom of the upper limb, the lateral part of scapula has to travel wide. Such modification of the position of scapula occurs at the acromioclavicular joint, when the acromion glides on the clavicle. The movements of the free upper limb are thus protected and the all-too-important functions like grasp, grip, prehensility, push and forward thrust are maintained.

Alternative treatment choices are fluoroquinolones and trimethoprim-sulfamethoxazole womens health 9 positions purchase 50 mg ardomon, should susceptibility be confirmed by formal testing women's health boca raton ardomon 100 mg order on-line. Extended-spectrum -lactamases are carried on plasmids and may be transferred among members of the Enterobacteriaceae group women's health york pa ardomon 50 mg without prescription. Carbapenemases: these are carbapenem-hydrolyzing -lactamases that confer resistance to all -lactams and carbapenems women's health worcester ma order ardomon 50 mg with visa. Klebsiella pneumoniae carbapenemases have become endemic in certain parts of the United States (North East and areas in the Midwest); they are also endemic in Israel women's health issues-night sweats cheap ardomon 25 mg line, China, Greece, Europe, and parts of South America [2]. New Delhi metallo-lactamases have been reported in at least 15 states in the United States [6], they are endemic in India, and they are also rapidly disseminating worldwide [1, 3]. Carbapenemases have also been found in nonfermenting Gram-negative bacteria such as Acinetobacter sp and Pseudomonas sp. Porins are structural pores in the outer membranes of bacteria, which serve as a permeability barrier but also allow for the entry of antimicrobials into the cell. Epidemiology and Risk Factors for Multidrug-Resistant Enterobacteriaceae the rates of drug-resistant Gram-negative bacteria are rising. Diagnostic Considerations Bacterial identification and susceptibility testing is key in the diagnosis and management of drug-resistant. In the Hodge test, a meropenem or ertapenem disk is placed in on an agar plate with a lawn of susceptible E coli. Although the modified Hodge test is useful as a phenotypic screening test for carbapenemases. Molecular confirmation of the specific resistance gene is considered the gold standard. As exemplified in this case, the relatively slow turnaround time for bacterial culture and susceptibilities is a major barrier to the initiation of early and appropriate therapy. As illustrated here, choosing an effective empiric antibiotic treatment may be difficult. If ineffective, this can lead to devastating consequences, especially in immunosuppressed hosts. Definitive treatment of drug-resistant, Gram-negative bacilli should be guided by antimicrobial susceptibility testing. Quinolones may also be used, if the isolate is susceptible, in less severe types of infections. Combination of these antimicrobials with rifampin may also be considered, and this is supported by an in vitro data demonstrating potential synergy with polymyxin, carbapenem, and rifampin combination [4]. Other strategies that could be used include the use of high-dose, extended infusion therapy with carbapenems in combination with other antimicrobials, such as colistin/ polymyxin B. The dilemma in treating drug-resistant Gram-negative bacteria calls for the "fast-track" development of new antimicrobials. Theglobalchallenge of carbapenem-resistant enterobacteriaceae in transplant recipients and patients with hematologic malignancies. Epidemiology of conjugative plasmid-mediated AmpC beta-lactamases in the United States. Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance. Community-associated extended-spectrum beta-lactamase-producing Escherichia coli infection in the United States. Urinary tract infections due to multidrug-resistant Enterobacteriaceae: prevalence and risk factors in a Chicago emergency department. Predictors and molecular epidemiology of community-onset extended-spectrum beta-lactamase-producing Escherichia coli infection in a Midwestern community. The importance of long-term acute care hospitals in the regional epidemiology of Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae. The rising influx of multidrug-resistant gram-negative bacilli into a tertiary care hospital. Transfer from high-acuity long-term care facilities is associated with carriage of Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae: a multihospital study. However, there are limited data for these agents against P aeruginosa and Acinetobacter sp. Infection control measures, such as hand hygiene and barrier precautions, are important in preventing the spread of these organisms in a healthcare setting, especially among immunocompromised hosts. Clinical epidemiology of the global expansion of Klebsiella pneumoniae carbapenemases. Prevalence of rectal colonization with multidrugresistant Enterobacteriaceae among international patients hospitalized at Mayo Clinic, Rochester, Minnesota. Outcomes of carbapenem-resistant Klebsiella pneumoniae infection and the impact of antimicrobial and adjunctive therapies. Tracking a hospital outbreak of carbapenem-resistant Klebsiella pneumoniae with whole-genome sequencing. Clinical evaluation of the FilmArray blood culture identification panel in identification of bacteria and yeasts from positive blood culture bottles. Rapid detection of carbapenemase-producing Enterobacteriaceae from blood cultures. Evaluation of an automated rapid diagnostic assay for detection of gram-negative bacteria and their drug-resistance genes in positive blood cultures. He was diagnosed five months earlier with a presentation of reflux symptoms and general indigestion. Esophagoduodenoscopy was unremarkable so it was followed by imaging of his liver that revealed a 15 × 13 × 11 cm mass in the left hepatic lobe. He underwent partial hepatectomy with pathology revealing high-grade undifferentiated sarcoma. Two months after surgery, he developed lung metastasis and began doxorubicin and ifosfamide chemotherapy at that time. He progressed after two cycles and has been on second-line gemcitabine and docetaxel for the last six weeks with disease response. At a clinic visit, he complained of poor appetite, low-grade fevers, and a nonproductive cough that began one week earlier. His weight, although initially down after starting chemotherapy, has been stabilizing over the last several weeks. He was normotensive at 112/76 mm mercury but tachycardic to 117 beats per minute, with a temperature of 36. He appeared thin but comfortable, and his exam was unremarkable except for slight inspiratory crackles worse on right than left. Complete metabolic panel was unremarkable apart from mild hyponatremia of 130 mmol/L. Atypical pneumonia caused by Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella pneumophila, or Haemophilus influenza should be considered. Viral pneumonia from influenza, adenovirus, parainfluenza, respiratory syncytial virus, or human metapneumovirus infection should also be considered. Fungal pneumonia due to Aspergillus species or Cryptococcus neoformans would be highly unlikely in a solid tumor patient but would be a consideration for patients with chronic neutropenia. Cytomegalovirus pneumonia is most commonly seen in patients with graft-versus-host disease after an allogeneic stem cell transplant. Pneumocystis jiroveci is a consideration with immunosuppression and especially lymphocytopenia. A definitive diagnosis typically requires direct visualization on a diagnostic specimen and was not obtained in this case. He did require ondansetron thirty minutes prior to his doses to combat antibiotic-induced nausea. Identifying patients at risk for infection is the most important step for prevention. There is some debate regarding the dose and duration of corticosteroid that confers risk. According to National Comprehensive Cancer Network guidelines, patients receiving doses equivalent to 20 mg of prednisone daily or greater for at least four consecutive weeks or longer should be given primary prophylaxis [2]. Additional risk factors are related to impaired or decreased lymphocyte counts (<500 cell/L) and include patients with hematologic or solid organ transplantation, inherited immunodeficiency syndromes, or those receiving immunosuppression with or without corticosteroids for various inflammatory or rheumatologic conditions. Among cancer patients (and other immunosuppressed individuals), symptoms onset is usually more abrupt in the manner of a few days with dyspnea, hypoxia, dry cough, and low-grade fevers. Pleuritic chest pain or sudden onset of dyspnea should raise suspicion for a pneumothorax. Typical findings include bilateral perihilar interstitial infiltrations with increasing amounts of ground-glass opacification as the infection progresses. Pneumocele or pneumothorax along with cystic lesions may computed tomography of chest showing multifocal,ground-glass opacities besides previously known metastases. Obtaining the gold standard of microscopic visualization of the organisms is difficult, and staining of sputum, oropharyngeal, or bronchoalveolar wash samples may not be definitive. Nevertheless, bronchoscopy with bronchoalveolar lavage should be considered when sputum staining is negative but a strong clinical suspicion remains. Supportive laboratory evidence exists in a serum assay for fungal wall carbohydrates in the form of 1,3-d-glucan. A commercial test (Fungitell) has been available since 2003 and has been used for invasive fungal infections from candidiasis or Aspergillus. However, using steroids to suppress the associated inflammation of a moderate to severe respiratory infection with hypoxia may be a beneficial strategy. Adverse prognostic factors include intubation delay, longer duration of positive pressure ventilation, and pneumothorax [10]. Prevention As with any opportunistic infection, primary prophylaxis in the properly recognized cancer situation (Table 1. Most patients with acute leukemia, allogeneic, and autologous bone marrow transplant recipients should be considered for prophylaxis. Common medications used during cancer care requiring consideration for prophylaxis also include alemtuzumab, fludarabine, prolonged corticosteroids, and concurrent temozolomide and radiation therapy. Trimethoprim-sulfamethoxazole can be given safely with methotrexate without significant concern for side effects such as marrow suppression [14]. Acute respiratory failure due to Pneumocystis pneumonia in patients without human immunodeficiency virus infection: outcome and associated features. A systematic review of two different trimetoprimsulfamethoxazole regimens used to prevent Pneumocystis jirovecii and no prophylaxis at all in transplant recipients: appraising the evidence. Ananalysis of the utilisation of chemoprophylaxis against Pneumocystis jirovecii pneumonia in patients with malignancy receiving corticosteroid therapy at a cancer hospital. Diagnostic accuracy of serum 1,3-beta-D-glucan for Pneumocystis jiroveci pneumonia, invasive candidiasis, and invasive aspergillosis: systematic review and meta-analysis. An official American Thoracic Society statement: Treatment of fungal infections in adult pulmonary and critical care patients. A randomized trial of three antipneumocystis agents in patients with advanced human immunodeficiency virus infection. For two years, he was managed with alternative and experimental therapy while participating on a clinical trial in Mexico. He remained intubated for airway protection on minimal ventilator settings with fraction of inspired oxygen (FiO2) of 40% and minimal suction requirements. Initial work up for neutropenic fever included blood cultures, chest radiograph, bronchoalveolar lavage, and initiation of empiric broad-spectrum antibiotics (meropenem). Over the next few days, computed tomography scans of the neck, chest, abdomen, and pelvis were repeated. Mental status had been steadily improving over time (intensive care unit delirium), and he was regaining strength. Physical exam at the time of initial fevers was notable for a very thin, cachectic male without skin rashes. Laboratory evaluation was notable for absolute neutropenia with a white blood cell count <0. Despite the lack of parenchymal pulmonary infiltrates, a bronchoalveloar lavage was performed for evaluation of persistent fevers, which grew methicillin-resistant Staphylococcus aureus, Klebsiella pneumoniae, and Achromobacter spp. Fevers persisted after six days of broad-spectrum antibiotics (vancomycin and meropenem) and thirteen days of Computed tomography neck. Repeat daily blood cultures continued to grow this yeast on six consecutive days (Table 1. Candida spp represent the most common blood yeast isolate [1], with the incidence of non-albicans Candida species increasing over time (cohort from 2005 to 2007 compared with 1997 to 2000) [2]. Some species of Candida can develop echinocandin resistance such as Candida glabrata or Candida parapsilosis. Endemic fungi can be a consideration in a patient with sepsis and fungemia breakthrough on echinodandin therapy. The most common endemic fungus known to grow in blood would be disseminated histoplasmosis. This patient would have been at risk for other endemic fungi such as paracoccidioidomycosis and coccidioidomycosis because he was native to Mexico. Other than Histoplasma, these tend to present with pulmonary infiltrates or lymphadenopathy and are often diagnosed from tissue biopsy samples, not from blood cultures. These non-Candida opportunistic yeasts are often resistant to echinocandins and are known to cause fungemia in cancer patients. Included among them are Cryptococcus, Trichosporon, Saccharomyces, Rhodotorula, and Geotrichum. Infections with Geotrichum geographically occur in Europe (Italy, Spain, and France), whereas Trichosporon is distributed worldwide [3]. No true hyphae Antifungal Susceptibilities Sensitive to amphotericin, azoles, often combination with flucytosine is used. Resistant to echinocandins Trichosporon Fungemia, dissemination, Hyphae (septate), pseudohyphae, pneumonia barrel-shaped arthroconidia, pleomorphic budding yeast (blastoconidia) Trichosporon asahii susceptible to voriconazole and posaconazole. Geotrichum Fungemia, dissemination, Arthroconidia are unicellular, in pneumonia chains, rectangular or barrel shape. Rhodotorula Fungemia, central catheter-associated infections Unicellular blastoconidia, globose Sensitive to amphotericin, itraconazole, and to elongated in shape.

Fat-soluble vitamins are A menstrual yeast infections buy ardomon 100 mg without a prescription, D menstrual related hypersomnia discount ardomon 100 mg overnight delivery, E women's health issues in the 19th century discount ardomon 100 mg mastercard, and K; the water-soluble group includes the B vitamins and vitamin C pregnancy order ardomon with american express. Therefore they associate with lipids and are influenced by the same factors that affect lipid absorption breast cancer youngest age purchase ardomon in united states online. For example, bile salts in the intestine promote absorption of fat-soluble vitamins. The fat-soluble vitamins are stored in moderate quantities in various tissues, which is why excess intake can lead to overdose. These vitamins resist the effects of heat, so cooking and food processing do not usually destroy them. Body cells synthesize this vitamin from a group of yellowish plant pigments, which are provitamins called carotenes (fig. Excess vitamin A or its precursors are mainly stored in the liver, which regulates their concentration in the body. Vitamins are essential nutrients that must come directly from foods or indirectly from provitamins, which are precursor substances. Infants and children usually lack such reserves and are therefore more likely to develop vitamin A deficiencies if their diets are inadequate. Retinal is used to synthesize rhodopsin (visual purple) in the rods of the retina and light-sensitive pigments in the cones (pp. The vitamin also functions in the synthesis of mucoproteins and mucopolysaccharides, in development of normal bones and teeth, and in maintenance of epithelial cells in skin and mucous membranes. Vitamin A and beta carotenes also act as antioxidants (anti -oksi -dant) by readily combining with oxygen and certain oxygen-containing molecules that have unshared electrons, which makes them highly reactive and damaging to cellular structures. These unstable molecules are called oxygen free radicals, and they accumulate in certain diseases and with age. Only foods of animal origin such as liver, fish, whole milk, butter, and eggs are sources of vitamin A. Excess vitamin A produces the peeling skin, hair loss, nausea, headache, and dizziness of hypervitaminosis A. Chronic overdoses of the vitamin may inhibit growth and break down bones and joints. A deficiency of vitamin A causes night blindness, in which a person cannot see normally in dim light. Xeropthalmia, a dryness of the conjunctiva and cornea, is due to vitamin A deficiency. Vitamin A deficiency also causes degenerative changes in certain epithelial tissues, and the body becomes more susceptible to infection. One of these substances, vitamin D3 (cholecalciferol), is found in foods such as milk, egg yolk, and fish liver oils. Vitamin D 2 (ergocalciferol) is commercially produced by exposing a steroid obtained from yeasts (ergosterol) to ultraviolet light. Vitamin D can also be synthesized from dietary cholesterol that has been metabolized to provitamin D by intestinal enzymes, then stored in the skin and exposed to ultraviolet light (see chapter 6, p. Like other fat-soluble vitamins, vitamin D resists the effects of heat, oxidation, acids, and bases. It is primarily stored in the liver and is less abundant in the skin, brain, spleen, and bones. Vitamin D stored in the form of hydroxycholecalciferol is released as needed into the blood. When parathyroid hormone is present, this form of vitamin D is converted in the kidneys into an active form of the vitamin (dihydroxycholecalciferol). This substance, in turn, is carried as a hormone in the blood to the intestines where it stimulates production of calcium-binding protein. Here, it promotes absorption of calcium and phosphorus, ensuring that adequate amounts of these minerals are available in the blood for tooth and bone formation and metabolic processes. Natural foods are poor sources of vitamin D, so the vitamin is often added to them during processing. For example, homogenized, nonfat, and evaporated milk are typically fortified with vitamin D. Fortified means essential nutrients have been added to a food where they originally were absent or scarce. Enriched means essential nutrients have been partially replaced in a food that has lost nutrients during processing. Excess vitamin D, or hypervitaminosis D, produces diarrhea, nausea, and weight loss. Over time too much of this vitamin may calcify certain soft tissues and irreversibly damage the kidneys. In children, vitamin D deficiency results in rickets, in which the bones, teeth, and abdominal muscles do not develop normally Absorption And excretion (fig. In adults or in the elderly who have little exposure to sunlight, vitamin D deficiency may lead to osteomalacia, in which the bones decalcify and weaken due to disturbances in calcium and phosphorus metabolism. Just five minutes of sun exposure two to three times a week can maintain skeletal health without elevating skin cancer risk. Because many older people stay indoors, the Institute of Medicine suggests that daily vitamin D intake increase with age (table 18. Vitamin E includes a group of compounds, the most active of which is alpha-tocopherol. This vitamin is resistant to the effects of heat, acids, and visible light but is unstable in bases and in the presence of ultraviolet light or oxygen. Vitamin E is found in all tissues but is primarily stored in the muscles and adipose tissue. The precise functions of vitamin E are unknown, but it is thought to act as an antioxidant by preventing oxidation of vitamin A and polyunsaturated fatty acids in the tissues. Other good sources are salad oils, margarine, shortenings, fruits, nuts, and vegetables. Excess vitamin E may cause nausea, headache, fatigue, easy bruising and bleeding, and muscle weakness. One of these, vitamin K1 (phylloquinone), is found in foods, whereas another, vitamin K2, is produced by bacteria (Escherichia coli) that normally inhabit the human intestinal tract. These vitamins resist the effects of heat but are destroyed by oxidation or by exposure to acids, bases, or light. Vitamin K primarily functions in the liver, where it is necessary for the formation of several proteins needed for blood clotting, including prothrombin (see chapter 14, pp. Consequently, deficiency of vitamin K prolongs blood clotting time and may increase risk of hemorrhage. Excess vitamin K may occur in formula-fed infants, causing jaundice, hemolytic anemia, and hyperbilirubinemia. About 1 in every 200 to 400 newborns develops vitamin K deficiency because of an immature liver, poor transfer of vitamin K through the placenta, or lack of intestinal bacteria that can synthesize this vitamin. Adults may develop vitamin K deficiency if they take antibiotic drugs that kill the intestinal bacteria that manufacture the vitamin. Vitamin d deficiency in childhood causes bone Q Why would vitamin D deficiency cause bone deformities Water-Soluble Vitamins the water-soluble vitamins include the B vitamins and vitamin C. They help oxidize (remove electrons from) carbohydrates, lipids, and proteins during cellular respiration. The B vitamins are usually in the same foods, so they are called the vitamin B complex. Thiamine, or vitamin B1, in its pure form is a crystalline compound called thiamine hydrochloride. Specifically, thiamine is required for pyruvic acid to enter the citric acid cycle (see chapter 4, p. Only small amounts are stored in the tissues, and excess is excreted in the urine. Vitamin B1 oxidizes carbohydrates, and therefore cellular requirements vary with caloric intake. Good sources of thiamine are lean meats, liver, eggs, whole-grain cereals, leafy green vegetables, and legumes. Excess thiamine is not as common as excesses of fatsoluble vitamins, due to the excretion of thiamine in urine. Toxicity effects include vasodilation, cardiac dysrhythmias, headache, weakness, and convulsions. Prolonged deficiency leads to a disease called beriberi, which causes gastrointestinal disturbances, mental confusion, muscular weakness and paralysis, and heart enlargement. Riboflavin, or vitamin B2, is a yellowish brown crystalline substance that is relatively stable to the effects of heat, acids, and oxidation but is destroyed by exposure to bases and ultraviolet light. Flavoproteins are essential for the oxidation of glucose and fatty acids and for cellular growth. An active transport system controls the amount of riboflavin entering the intestinal mucosa. Excess riboflavin in the blood is excreted in the urine, turning it yellow-orange, and any that remains unabsorbed in the intestine is lost in the feces. Riboflavin is widely distributed in foods, and rich sources include meats and dairy products. Leafy green vegetables, whole-grain cereals, and enriched cereals provide lesser amounts. Niacin or vitamin B3, also known as nicotinic acid, is in plant tissues and is stable in the presence of heat, acids, and bases. After ingestion, it is converted to a physiologically active form called niacinamide (fig. They are also required for the synthesis of the sugars (ribose and deoxyribose) that are part of nucleic acids. Niacin is readily absorbed from foods, and human cells synthesize it from the essential amino acid tryptophan. Rich sources of niacin (and tryptophan) include liver, lean meats, peanut butter, and legumes. Excess niacin can cause acute toxicity with effects such as flushing, wheezing, vasodilation, headache, diarrhea, and vomiting. Historically, niacin deficiencies have been associated with diets based on corn and corn products, which are very low in niacin and lack tryptophan. Niacin deficiency causes pellagra, which produces dermatitis, inflammation of the digestive tract, diarrhea, and mental disorders. Pellagra is rare today, but it was a serious problem in the rural South of the United States in the early 1900s. Like beriberi, pellagra affects people who consume alcoholic beverages instead of food. Pantothenic acid, or vitamin B5, is a yellowish oil destroyed by heat, acids, and bases. It functions as part of a complex molecule called coenzyme A, which, in turn, reacts with intermediate products of carbohydrate and fat metabolism to yield acetyl coenzyme A, which enters the citric acid cycle. Good sources of pantothenic acid include meats, whole-grain cereals, legumes, milk, fruits, and vegetables. Vitamin B6 is a group of three compounds, pyridoxine, pyridoxal, and pyridoxamine, which are chemically similar (fig. These compounds have similar actions and are fairly stable in the presence of heat and acids. The vitamin B6 compounds function as coenzymes essential in several metabolic pathways, including those that synthesize proteins, amino acids, antibodies, and nucleic acids, as well as the reaction of tryptophan to produce niacin. Thus, the requirement for this vitamin varies with the protein content of the diet rather than with caloric intake. Good sources of vitamin B6 include liver, meats, bananas, avocados, beans, peanuts, whole-grain cereals, and egg yolk. Excess vitamin B6 produces burning pains, numbness, clumsiness, diminished reflexes, and paralysis. Biotin, or vitamin B7, is a simple compound that is unaffected by heat, acids, and light but may be destroyed by oxidation or bases. It also plays a role in the synthesis of the purine nitrogenous bases of nucleic acids (adenine and guanine). Metabolically active organs such as the brain, liver, and kidneys store some biotin. Folacin or vitamin B9, also known as folic acid, is a yellow crystalline compound that exists in several forms. It is easily oxidized in an acid environment and is destroyed by heat in alkaline solutions; consequently, this vitamin may be lost in stored or cooked foods. Folacin is readily absorbed from the digestive tract and is stored in the liver, where it is converted to a physiologically active substance called folinic acid. Good sources of folacin include liver, leafy green vegetables, whole-grain cereals, and legumes. Folacin deficiency leads to megaloblastic anemia, in which the number of normal red blood cells is reduced and large, nucleated red cells appear. Folacin deficiency has been linked to neural tube defects, in which the tube that becomes the central nervous system in a fetus does not completely close. Taking synthetic folic acid supplements just before and during pregnancy can greatly reduce the risk of a neural tube defect. However, synthetic folic acid is much more stable and enters the bloodstream much more readily. For example, 200 micrograms of synthetic folic acid is prescribed to treat anemia, but the same effect requires 400 micrograms of folate from foods.

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