Genitalia

In the majority of vertebrates, sex is determined by genetic composition, but this is by no means universal. In most species, the genes of an individual direct all of the later ontogenetic processes involved in male-female differentiation of the genitalia and associated structures. 

Amoebal infections, particularly of farm animals and the female human genitalia, are at best only annoying. All too often the problem encountered leads to difficult diarrheas. A group of nitroimidazoles have activity against the causative organisms and consequently have been widely synthesized. 

The most significant metabolic product of testosterone is DHT, since in many tissues, including prostate, external genitalia, and some areas of the skin, this is the active form of the hormone. The plasma content of DHT in the adult male is about one-tenth that of testosterone, and approximately 400 ig of DHT is produced daily as compared with about 5 mg of testosterone. About 50-100 ig of DHT are secreted by the testes. The rest is produced peripherally from testosterone in a reaction catalyzed by the NADPH-depen-dent 5oi-reductase (Figure 42-6). Testosterone can thus be considered a prohormone, since it is converted into a much more potent compound (dihydrotestosterone) and since most of this conversion occurs outside the testes. Some estradiol is formed from the peripheral aromatization of testosterone, particularly in males. 

Urine may be collected for assays of enzyme activities following cleansing of the genitalia with mild antiseptic soap followed by rinsing with water. The urine is collected in a chemically clean container with no preservative. As the activity of urinary enzymes is a function of the volume of the specimen it is important to time the collection accurately. A collection period of 8 hours is quite adequate, and the use of longer periods is not desirable because enzyme activities can rapidly decrease in the relatively hostile medium of the urine. The urine should be refrigerated and transferred promptly to the laboratory, where it should also be processed promptly. 

Similar constant checking across the cycle occurs in the Spider monkey (Ateles), where males directly sniff and nasally contact the females complex labial folds. The external genitalia lack visual peri-ovulatory alterations, hence usage of the AOS may occur. It is however unestablished in this, as in many other species without overt vulval colour change (Klein, 1971 Hunter et al., 1984). 

Hyperpigmentation of skin (usually around creases, pressure areas, areolas, genitalia, and new scars) and mucous membranes. Dark freckles and patches of vitiligo may be present. Hyperpigmentation, owing to increased ACTH levels, occurs in primary adrenal insufficiency. 

Diaper dermatitis, more commonly known as diaper rash, is a form of irritant contact dermatitis that affects the buttocks, upper thighs, lower abdomen, and genitalia of an estimated 7% to 35% of all infants.34,35 Onset of occurrence is usually between 3 weeks and 2 years of age, with the most cases reported between 9 and 12 months of age.36 More than 12 million adults who use diapers for incontinence also have an increased risk of developing diaper dermatitis.35... 

E. histolytica invades mucosal cells of colonic epithelium, producing the classic flask-shaped ulcer in the submucosa. The trophozoite toxin has a cytocidal effect on cells. If the trophozoite gets into the portal circulation, it will be carried to the liver, where it produces abscess and periportal fibrosis. Liver abscesses are more common in men than women and are rarely seen in children. Amebic ulcerations can affect the perineum and genitalia, and abscesses may occur in the lung and brain. 

Congenital syphilis is a condition in which the fetus is infected with T. pallidum as a result of the hematogenous spread from an infected mother, although transmission may also occur from direct contact with the infectious genitalia of the mother. Since the primary stage of syphilis is characterized by spirochetemia, infectious rates of the fetus are nearly 100% if the mother has primary syphilis.11... 

Evidence that BPH could be hormone related came from studies of a population of pseudohermaphrodites in the Dominican Republic. These individuals are genetically male, but do not display normal male genitalia until the onset of puberty. They are therefore raised as females until puberty. Studies revealed that these pseudohermaphrodites are deficient in an isoform of the enzyme steroid 5a-reductase, which is responsible for catalyzing the conversion of testosterone to dihydrotestosterone (DHT). In addition to the overt sexual manifestations of this condition, affected individuals show no incident of male pattern baldness, mild or no acne, and underdevelopment of the prostate. These observations led researchers to postulate that a selective inhibitor of steroid 5a-reductase would be an effective treatment for BPH. 

While nitrofurans are often prepared as antibacterial agents, nitroimidazole forms the basis for an extensive class of agents used in the treatment of infections by the protozoans. Unlike bacterial infections, protozoal infections are seldom life-threatening. The physical discomfort occasioned by such infections is, however, of sufficient importance to provide a useful therapeutic place for antiprotozoal agents. A particularly common set of such conditions are parasitic infections of the genitalia caused by Trichomonas vaginalis. These disorders are called trichomoniasis. 

A key factor affecting the length of time before the onset of symptoms as well as the severity of the symptoms is the part of the body that is exposed to the agent. Apart from mucous membranes, the regions of the body that are the most sensitive to vesicants are warm, moist areas, and areas with thin skin such as the face, armpits, inside of the elbow, genitalia, neck, skin between the fingers, and the nail beds. The least susceptible body regions are the palms of the hands, soles of the feet, front of the knee, and outside of the elbow. 

Signs and Symptoms Initial symptoms include fever, watery eyes, increased nasal secretions, drooling (ptyalism), diarrhea, loss of appetite, reduced milk production, depression, and reluctance to move. This is followed by the eruption of various sized skin nodules that may cover the whole body. They can be found on any part of the body but are most numerous on the head and neck, perineum, genitalia and udder, and the limbs. The nodules are painful and involve all layers of the skin. Skin lesions may show scab formation. Regional lymph nodes are enlarged and full of fluid. Secondary bacterial infection can complicate healing and recovery. Final resolution of lesions may take 2-6 months, and nodules can remain visible 1-2 years. 

Diaper dermatitis (diaper rash) is an acute, inflammatory dermatitis of the buttocks, genitalia, and perineal region. The reaction is a type of contact dermatitis, as it results from direct fecal and moisture contact with the skin in an occlusive environment. 

Patient age and hormonal status in women should be considered in the initial evaluation of patients with skin disorders. Older patients are predisposed to developing psoriasis, seborrhea, and other skin conditions. Atopic dermatitis is most likely to occur in children. Menopausal women tend to develop brown hyperpigmentation, or melasma. Pregnant women may develop hyperpigmentation of the areola and genitalia as well as melasma. 

Primary External genitalia, perianal region, mouth, and throat... 

Most primary infections are asymptomatic or minimally symptomatic Multiple painful pustular or ulcerative lesions on external genitalia developing over a period of 7-10 days lesions heal in 2-4 weeks (mean, 21 days)... 

Anderson, C. and Clark, R.L. (1990). External genitalia of the rat Normal development and the histogenesis of 5a-reductase inhibitor-induced abnormalities. Teratology 42 483-496. 

Clark, R.L., Anderson, C.A., Prahalada, S., Leonard, Y.M., Stevens, J.L. and Hoberman, A.M. (1990a). 5a-reductase inhibitor-induced congenital abnormalities in male rat external genitalia. Teratology 41 544. 

Clark, R.L., Antonello, J.M., Grossman, J.T., Wise, L.D., Anderson, C., Bagdon, W.J., Prahalada, S., MacDonald, J.S. and Robertson, R.T. (1990b). External genitalia abnormalities in male rats exposed in utero to finasteride, a 5a-reductase inhibitor. Teratology 42 91-100. 

Overview of Study Design. Four groups of five adult rabbits each receive a single vaginal exposure daily for 10 days. The genitalia are examined daily. Animals are then euthanized and the vagina is examined macroscopically and microscopically. 

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