Etiologic

Beriberi, Thiamine Deficiency. The recognition of vitamins and their importance to the health of human beings came about when Eijkman, a Dutch pathologist, was sent to Java in an attempt to cure an epidemic of beriberi that had appeared in one of the hospitals. Eijkman kept a flock of chickens on the hospital grounds to assist in discovering the disease agent he assumed was involved in the etiology of beriberi. These chickens were fed the scraps from the plates of the hospital patients—primarily poHshed rice, the common food in that part of the world (11). 

Urethane [51-79-6] (ethyl carbamate) occurs as a natural by-product in fermented products such as wine, Hquors, yogurt, beer, bread, oHves, cheeses, and soy sauces. Whereas urethane has a known cancer etiology in experimental animals, no such relationship has yet been proven in humans (108,109). Alcohol may act by blocking the metaboHsm of urethane, and thus exert a protective effect in humans consuming alcohoHc beverages (110). 

Clinically Efficacy. It is evident from the mechanism of action of antihistamines and the etiology of allergic diseases that antihistamines in no sense achieve a cure of the patient s allergy. After the adrninistration of a therapeutic dose, a temporal blockade of the effects of histamine is obtained. Whereas classical antihistamines needed at least twice daily adrninistration, for most of the more recently introduced agents adrninistration once daily is sufficient. 

There ate many classes of anticonvulsant agent in use, many associated with side effect HabiUties of unknown etiology. Despite many years of clinical use, the mechanism of action of many anticonvulsant dmgs, with the exception of the BZs, remains unclear and may reflect multiple effects on different systems, the summation of which results in the anticonvulsant activity. The pharmacophore stmctures involved are diverse and as of this writing there is htde evidence for a common mechanism of action. Some consensus is evolving, however, in regard to effects on sodium and potassium channels (16) to reduce CNS excitation owing to convulsive episodes. 

There are multiple causes of diabetes. Whereas the molecular bases of some forms of diabetes are well understood, in many cases etiologies are unknown. It is customary to divide diabetes into two main forms insulin-dependent diabetes mellitus (IDDM), also referred to as Type I or juvenile-onset diabetes, and noninsulin-dependent diabetes mellitus (NIDDM), also called Type II or maturity-onset diabetes (3). 

Like mAChRs, nAChRs have been implicated in the etiology of ALheimef s disease and related dementias as well as in gastrointestinal and cardiovascular disorders. Nicotine has high abuse potential and is the primary component in reinforcing smoking behaviors. Nicotine patches have been... 

Amylin [106602-62-4] (75) (Fig. 4) is a 37-amino acid peptide having approximately 46% sequence similarity to CGRP (33). Amylin is present ia pancreatic P-ceUs along with insulin. It may function as a hormone ia glucoregulation and has been proposed as an etiologic factor ia certain forms of diabetes. Amylin is also present ia dorsal root ganglia (see INSULIN AND OTHER ANTIDIABETIC DRUGS). 

Insomnia complaints are common in the general population and can be dichotomized into problems of delayed sleep onset and those related to sleep maintenance. Increasing attention is being focused on the adverse daytime effects of insomnia. Sleep disturbances become more common with increased age and are more prevalent in women. Sleep complaints arise from very diverse etiologies which prominently include concomitant primary... 

Inhibition of Nitrosamine Formation. Nitrites can react with secondary amines and A/-substituted amides under the acidic conditions of the stomach to form /V-nitrosamines and A/-nitrosamides. These compounds are collectively called N-nitroso compounds. There is strong circumstantial evidence that in vivo A/-nitroso compounds production contributes to the etiology of cancer of the stomach (135,136), esophagus (136,137), and nasopharynx (136,138). Ascorbic acid consumption is negatively correlated with the incidence of these cancers, due to ascorbic acid inhibition of in vivo A/-nitroso compound formation (139). The concentration of A/-nitroso compounds formed in the stomach depends on the nitrate and nitrite intake. 

Ascorbic acid also forms soluble chelate complexes with iron (142—145). It seems ascorbic acid has no effect on high iron levels found in people with iron overload (146). It is well known, in fact, that ascorbic acid in the presence of iron can exhibit either prooxidant or antioxidant effects, depending on the concentration used (147). The combination of citric acid and ascorbic acid may enhance the iron load in aging populations. Iron overload may be the most important common etiologic factor in the development of heart disease, cancer, diabetes, osteoporosis, arthritis, and possibly other disorders. The synergistic combination of citric acid and ascorbic acid needs further study, particularly because the iron overload produced may be correctable (147). 

In 1919, Huldschinski (8) realized that uv light cured rickets and impacted on its etiology. The uv light and codHver oil were found to be usehil in the treatment of the disease, and irradiation of food produced the same effect as irradiation of the animal. The link between irradiation and plant materials led to the conclusion that ergosterol was an antirachitic substance, and an extensive effort was made to characterize the chemistry of irradiated ergosterol. 

Cefuroxime (35) is effective against community-acquired pneumonia in which ampicillin-resistant Haemophilus influence is the probable etiologic agent. Cefoxitin (23) is used to treat mixed aerobic—anaerobic infections including pelvic infections, intra-abdorninal infections, and nosocomial aspiration pneumonia. Cefonicid (31), because of its long half-life has been used in a once-a-day regimen to treat a variety of mild to moderate infections including community-acquired pneumonias, urinary tract infections, and infections of the skin and soft tissue (132,215). 

To mycologists, each fungal infection has something specific, either in its symptomatology or its etiology. However, this is less obvious to practitioners. The incidence and the severity of the pathology are sometimes underestimated. Mycoses may be classified as follows ... 

Hypertension is one of the two principal risk factors of many cardiovascular diseases, such as coronary heart disease (CHD), stroke, and CHF. Individuals are considered hypertensive if their systoHc arterial blood pressure is over 140 mm Hg (18.7 Pa) or their diastoHc arterial blood pressure is over 90 mm Hg (12 Pa). Over 60 million people, or one-third of the adult population in the United States are estimated to be hypertensive (163). About 90% of these patients are classified as primary or essential hypertensive because the etiology of their hypertension is unknown. It is generally agreed that there is a very strong genetic or hereditary component to this disease. 

I. P. Semmelweis, The Etiology, Conception and Prophylaxis of Childbed Fever, Harfleben. Pest, Vienna Leipsig, 1861. 

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