Etiology dependence

From the standpoint of biochemical individuality, one suspects that common colds have diverse etiologies, depending upon the susceptibilities of the individual concerned, the distinctive flora which he supports, and the various infective agents which can cause symptoms of about the same type. If this is the case, then the search for a single means of combating common colds will probably always be fruitless, and we will have to be content with a series of measures that will be effective for different groups of people when they have different types of infections. 

PTT is based on a combination of reverse-transcription polymerase chain reaction (RT-PCR) and linked in vitro transcription and translation (Fig. 3C). This combination of procedures can selectively detect translation-terminating or nonsense mutations. Unfortunately, it does not find missense mutations, which may be etiologic, depending upon location. 

Evidence ranking level for etiology depends on the design and quality of studies. The highest level is ranked la and decreases downward. Table modified from the Oxford Centre for Evidence-based Medicine Levels of Evidence website (www.cebm.net/index.aspx o=1025), produced since November 1998 by Bob Phillips, Chris Ball, Dave Sacked, Doug Badenoch, Sharon Straus, Brian Haynes, Martin Dawes. Updated by Jeremy Howick in March 2009. 

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). 

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). 

Multiple factors interact in complex ways to result in opioid dependence. It is difficult to delineate, even for a specific individual, the precise etiology of dependence. In addition, each of the etiologic factors discussed in this section may play variable roles in initiation of use, maintenance of use, relapse, and recovery. Keeping in mind all of these potential factors is essential when formulating a treatment plan for each individual. 

MARSHALL J A, HAMMAN R F and BAXTER J (1991) High-fat, low-carbohydrate diet and the etiology of non-insulin-dependent diabetes mellitus the San Luis Valley diabetes study. J Epidemiol. 134 (6) 590-603. 

Etiologies of VT are presented in Table 6-10. The incidence of VT is variable, depending on underlying comorbidities. Up to 20% of patients who experience acute myocardial infarction... 

Patients will be in acute distress although symptoms and signs will vary depending on the severity of the hypovolemia and whether the etiology is hemorrhagic versus non-hemorrhagic. 

The treatment selected for PUD depends on the following factors (1) the etiology of the ulcer (2) whether the ulcer is new or recurrent and (3) the presence of any ulcer-related complications. Figure 15-2 contains an algorithm for the evaluation and treatment of a patient with signs and symptoms suggestive of an H. pylori-associated or NSAID-induced ulcer. 

Empiric antibiotic therapy is an appropriate approach to traveler s diarrhea. Eradication of the causal microbe depends on the etiologic agent and its antibiotic sensitivity. Most cases of traveler s diarrhea and other community-acquired infections result from enterotoxigenic (ETEC) or enteropathogenic (EPEC) Escherichia coli. Routine stool cultures do not identify these strains primary empiric antibiotic choices include fluoroquinolones such as ciprofloxacin or levofloxacin. Azithromycin may be a feasible option when fluoroquinolone resistance is encountered. 

Viral hepatitis can occur at any age and is the most common cause of liver disease in the world. The true prevalence and incidence may be underreported because most patients are asymptomatic. The epidemiology, etiology, and pathogenesis vary depending on the type of hepatitis and will be considered separately below. 

Evaluate the patient for appropriateness of pharmacologic therapy depending on etiology of Cushing s syndrome. 

Normal cardiac contraction depends on the conduction of electrical impulses through the myocardium in a highly coordinated fashion. Any abnormality of the initiation or propagation of the impulse is referred to as an arrhythmia. These disorders are the most common clinical problem encountered by a cardiologist. There is a wide range of types of arrhythmias with multiple etiologies and a variety of symptoms. In this section, two types of cardiac tachyarrhythmias are discussed. The most common treatment for these conditions is drug therapy. 

---