Measurement of body composition of live rats by electromagnetic conductance.

Measurement of body composition in vivo is important in many nutritional studies. One method for estimating body composition is total body electrical conductance (TOBEC). The TOBEC methodology is based on measuring changes of an electromagnetic field that are proportional to lean body mass (LBM). Sprague-Dawley rats (n = 117) ranging in age from 49 to 105 days were measured by TOBEC, and the TOBEC results were compared with direct carcass chemical analyses. The rats ranged in weight from 155 to 500 g. Mean LBM was 92.4% of total body weight (b.wt.), and mean body fat was 7.4% of total b.wt. Mean hydration of LBM was 71.7% and decreased (r = -0.59, p < 0.0001) with age. Using the manufacturer's supplied equation, TOBEC measurement underestimated actual LBM by 12% (p < 0.0001). As a consequence of this error, a new prediction equation was generated using half of the data set, and this equation was cross-validated with the other half of the data set. The mean LBM calculated from the new prediction equation was not different from chemically determined LBM, but the estimated percent body fat of some rats was negative. Thus, TOBEC may be useful in predicting mean LBM of a population, but this indirect method may lack the sensitivity to provide accurate estimates of body composition of an individual.

Vascular transformation of lymph node sinuses. A process displaying a spectrum of histologic features.

Nonneoplastic vascular lesions in lymph nodes have been infrequently reported. These lesions are believed to be rare and display histologic features ranging from minimal changes associated with vasodilation to vascular proliferative lesions resembling Kaposi's sarcoma. The spectrum of histologic features observed in these cases appears to be the result of the extent and duration of regional lymphatic and/or venous obstruction. We describe two such cases, one presenting in a 66-year-old black woman, after undergoing radical mastectomy for treatment of invasive ductal carcinoma of the breast following a breast biopsy; the other presenting in a 66-year-old black man with obstruction of the subclavian vein. We consider these cases worthy of review, both from a diagnostic standpoint and in the differential diagnosis of vascular neoplasms of lymph nodes, especially Kaposi's sarcoma.

Reefer madness: legal & moral issues surrounding the medical prescription of marijuana.

California, Arizona, and several other states have recently legalized medical marijuana. My goal in this paper is to demonstrate that even if one grants the opponents of legalization many of their contentious assumptions, the federal government is still obligated to take several specific steps toward the legalization of medical marijuana. I defend this claim against a variety of objections, including the claims: that marijuana is unsafe, that marijuana cannot be adequately tested or produced as a drug, that the availability of synthetic THC makes marijuana superfluous, and especially that legalizing medical marijuana will increase recreational use by 'sending the wrong message.' I then go on to argue that given the intransigent position of the federal government on this issue, state governments are justified in unilaterally legalizing medical marijuana as an act of civil disobedience. A large portion of this paper consists of an extensive response to the objection that legalizing medical marijuana will 'send the wrong message'--which I take to be the primary impediment to legalization. This objection basically claims that the consequences of withholding legalization (especially preventing increased recreational use) are superior to those of legalizing medical marijuana. I argue that legalization is justified even if one were to grant both that the harms of legalization outweighed its benefits and that utilitarianism is true. This requires a subtle and somewhat extended discussion of utilitarian moral and political theory.

Fat absorption in patients with functional intestinal lymphangiectasia and lymphangiectic cysts.

Nine patients with endoscopically identified dilated lacteals of the duodenum were studied for evidence of pathologic intestinal lymphangiectasia. Three of the nine patients also had lymphangietic cysts in association with dilated lacteals. Duodenal biopsies, laboratory data, and imaging studies were performed in each patient. In addition, a 14C triolein fat absorption study was performed to assess subclinical malabsorption. Biopsies revealed dilated lymphatic channels in all patients, but laboratory studies failed to suggest intestinal losses of protein or fat, and radiographic abdominal imaging failed to define any of the causes of secondary lymphangiectasia. Eight of the nine patients had adequate fat absorption as measured by the 14C triolein breath test. Our data suggest that patients with incidentally discovered dilated lacteals and no clinical evidence of malabsorption may have a functional intestinal lymphangiectasia. Follow-up endoscopy probably is not warranted in this population.

Prevalence of anti-HCV in cryptogenic cirrhosis in a suburban Detroit community.

To assess the role of the hepatitis C virus in patients with unexplained chronic liver disease, we tested for the presence of anti-hepatitis C antibody (anti-HCV) in the stored serum of patients with cryptogenic cirrhosis and a variety of other chronic liver diseases. The anti-HCV assay was performed by both the enzyme-linked and recombinant immunoblot methods in 16 patients with cryptogenic cirrhosis. Eight of these 16 patients (50%) were seropositive. Six of these eight patients were born outside of the United States, compared with only one of eight seronegative patients (p = 0.021). Of the anti-HCV-positive cryptogenic cirrhotic patients, 50% also had markers of previous hepatitis B infection, compared with only 12.5% of seronegative patients. Evidence of anti-HCV positivity was found in 10%, 19%, 0%, and 0% in patients with alcoholic cirrhosis, autoimmune hepatitis, primary biliary cirrhosis, and primary sclerosing cholangitis, respectively. We conclude that in a suburban American population, hepatitis C accounts for a significant percentage of patients with presumed cryptogenic cirrhosis. Unrecognized risk factors may account for a higher prevalence of HCV in foreign-born patients with cryptogenic cirrhosis. A low prevalence of anti-HCV positivity is found in other forms of chronic liver disease.

Correlation of the structure of amino-substituted anthraquinones to cytotoxicity in cultured Chinese hamster cells.

A number of substituted anthraquinones (SAQs) are currently being tested as cancer chemotherapeutic agents because of their structural similarity to Adriamycin (ADR) and other DNA-intercalating antibiotics. In this study, the effect of SAQs on the induction of cytotoxicity of asynchronous Chinese hamster cells in culture was studied and compared to those produced by ADR and dihydroxyanthraquinone (DHAQ), a SAQ previously shown to be more effective than ADR. SAQs produced cytotoxicity that was dependent upon the concentration and duration of drug exposure. A correlation was noted between the activity of a compound (the concentration required to produce a certain level of cell kill) and the presence of a particular triangular arrangement of one nitrogen atom and two oxygen atoms. There was also a correlation between chemical structure and antitumor activity in the murine P388 leukemia model system. This correlation between chemical structure and biological activity may aid in the development of new SAQs with greater potential as cancer chemotherapeutic agents.

Mortality of workers in an automobile engine and parts manufacturing complex.

A proportionate mortality ratio (PMR) study was conducted using data on workers from three local unions representing an integrated automobile factory composed of forge, foundry, and engine (machine and assembly) plants. Ninety four percent of the death certificates were obtained for all active and non-active workers who died during the period 1 January 1970 to 31 December 1979 and were vested in union and company benefit programmes. Observed numbers of deaths were compared with expected numbers based on two standards, the proportionate mortality among men in the United States 1970-9 and among men in Erie County 1975. There was close agreement between the number of observed and expected deaths by either standard of comparison among white auto workers in the forge and foundry plants. Valid analyses of cause specific mortality among non-whites could be conducted for the foundry plant only. Although there was raised PMR for deaths due to diseases of the circulatory system using the Erie County standard, none of the other cause specific PMRs was significant. Although based on small numbers, the risk of cancer of the lung was significantly high in non-whites under age 50 in the foundry (PMR = 2.6; p less than 0.05). The cause specific PMRs for whites in the engine plant were statistically significant for malignant neoplasms (1.2) and all external causes (0.62) based on the US white male standard. Analysis of cancer specific mortality among white men in the machining/assembly plant showed significant excesses for cancer of the digestive system (PMR=1.5), particularly of the liver (PMR=2.6) and pancreas (PMR=1.9); cancers of the respiratory system (PMR=1.4 using the Erie County standard); and cancer of the urinary bladder (PMR=2.3). Workers employed for more than 20 years showed statistically increased mortality ratios for cancers of the digestive system (1.9), particularly cancer of the pancreas (2.3) and cancer of the rectum (2.8). Individuals whose employment began during or before 1950 exhibited increased PMRs for cancers of the digestive organs (1.8), particularly of the pancreas (2.5) and of the bladder (3.4). Workers whose employment began after 1950, on the other hand, exhibited raised PMRs for cancers of the respiratory system (1.5) and of the kidney (3.2). Since the foundry and forge plants did not start production until 1955, mortality associated with those work settings may be greater in the future.

Mortality of a municipal worker cohort: II. Females.

Women have become an increasingly important segment of the total work force, yet there are very few published occupational mortality studies of female workers. This paper reports the findings of a retrospective cohort mortality study of 1,371 full-time female municipal employees of the City of Buffalo, New York, who were employed at least 1 day between January 1, 1950, and October 1, 1979, and who worked a minimum of 5 years. Vital status was ascertained for 88% of the female cohort, resulting in the identification of 214 observed deaths. This predominantly white-collar, service-oriented female cohort demonstrated significantly lower mortality than that expected based on U.S. mortality rates for white females. This strong "healthy-worker effect" was consistent across the time period of the study, across cause-specific mortality especially for all malignant neoplasms and all diseases of the circulatory system, and across different workers groups. Findings are discussed in light of the methodological issues involved in occupational studies of female workers.

Lack of evidence for the heterosexual transmission of hepatitis C.

To determine the potential for sexual transmission of the hepatitis C virus (HCV), we specifically studied a cohort of 42 young adults (median age, 39 yr) with chronic HCV infection and their stable sexual partners. All HCV assays were supplemented with the four-antigen recombinant immunoblot assay, and 39 of 42 partners were tested for HCV RNA by the nested polymerase chain reaction. Ninety percent of the partners reported frequent and unprotected sexual intercourse with the index patients. Two of 42 partners tested positive for the anti-HCV antibody and both were HCV RNA positive; one had independent risk factors for viral hepatitis. Therefore, one of 41 partners, (2.4%; 95% CI, 0.6-12.9%) without independent risk factors for HCV was anti-HCV positive. This woman was one of five partners (20%; 95% CI, 1-66%) who reported frequent razor-sharing with the index patient. The partner frequently sustained skin lacerations, with bleeding, secondary to this shared razor blade. We conclude that heterosexual transmission of hepatitis C is extremely uncommon, despite frequent and unprotected sexual intercourse.

Lifetime occupational exercise and colon cancer.

The authors used data on patients aged 30-79 years admitted to the Roswell Park Memorial Institute in Buffalo, New York, 1957-1965, to compare the amount of lifetime occupational physical activity for 210 white male patients with cancer of the colon and 276 white male patients with cancer of the rectum to the lifetime occupational physical exercise of 1,431 patients with nonneoplastic nondigestive diseases. The authors found that risk of cancer of the colon increased with increasing amount and proportion of time in jobs involving only sedentary or light work. This relationship was not found for rectal cancer. These findings corroborate those of Garabrant et al. (Am J Epidemiol 1984; 119:1005-14). The strength of the associations presented here and the dose-response relationship indicate that limited physical activity could be an important etiologic factor. More inquiries need to be undertaken to study exercise in relation to other factors, such as diet, in colon cancer risk.

Mortality of a municipal worker cohort: I. Males.

A retrospective cohort mortality study was conducted on 11,499 full-time municipal employees of the City of Buffalo, New York, who were employed at least one day between January 1, 1950 and October 1, 1979 and worked a minimum of five years. This paper outlines the method of the study and presents the all cause and cause-specific mortality for the male cohort of 10,128. Statistically significant deficits in mortality are seen for infectious diseases, diseases of the circulatory system, diseases of the respiratory system, and all external causes. Statistically significant increased mortality is seen for both malignant and benign neoplasms. All cause mortality was significantly lower than expected for professional, manager, and clerical workers. White-collar workers exhibit a decreased risk of mortality from all diseases of the circulatory system, all diseases of the respiratory system, and all external causes of death. No statistically significant increased or decreased risk of mortality from specific cancer sites is seen for white-collar workers. Blue-collar workers show statistically significant deficits in mortality from infectious diseases, all diseases of the circulatory system, all respiratory diseases, and all external causes. Blue-collar workers exhibit statistically significant increases for benign and malignant neoplasms and in particular, malignant neoplasms of the esophagus, large intestine, and rectum. The meaning of these findings will be clarified through analyses of specific worker groups.

Sources of bias in retrospective cohort mortality studies: a note on treatment of subjects lost to follow-up.

The three important sources of bias in retrospective cohort mortality studies are: the healthy worker confounding bias, the lost to follow-up bias, and bias due to methods of follow-up that result in underascertainment of deaths. This paper presents how the treatment of the lost to follow-up impacts ultimately on the apparent forces of mortality in a cohort. The findings are discussed in the context of the other sources of bias. The treatment of subjects lost to follow-up as lost at the time of loss offers the best estimate of expected mortality and should be the preferred approach.