The neonatal-thymectomy-induced mouse model of autoimmune oophoritis has two important similarities with human autoimmune oophoritis. First, in both cases there is some defect in the immune system that permits the development of organ-specific autoimmunity. Second, in both there is some ovarian target under attack. In neither case do we fully understand the nature of the immune defect or the ovarian target. Because of its strong analogy with the human disease, murine experimental postthymectomy autoimmune oophoritis may provide insight into the pathogenesis of autoimmune premature ovarian failure in women. Such studies may open new avenues toward the development of specific diagnostic and therapeutic methods. The histologic distribution of the ovarian lymphocytic infiltration is similar in the mouse and the human, and both mice and women with the disorder have reduced natural killer cell activity. Furthermore, susceptibility in both mice and women appears to be associated with genes outside the major histocompatibility complex. Finally, the mouse disorder is associated with a persistent neonatal-like Th2 response that suggests possible similarities with autoimmune polyglandular failure type 1 in humans. There is no currently available validated serum antibody marker that will confirm a clinical diagnosis of autoimmune premature ovarian failure. While investigating this animal model we cloned a novel gene that encodes an ooplasm-specific antigen associated with autoimmune oophoritis in mice. Based on its role in preimplantation development, we have designated this antigen Maternal Antigen That Embryos Require (MATER). MATER provides a new determinant with which to investigate the mechanisms of autoimmune premature ovarian failure.

Animals↗

PubMedDate not supplied

Household appliance use and residential exposure to 60-hz magnetic fields.

We characterized the distribution of exposure to magnetic fields (MFs) during daily activities and during household appliance use, and estimated the relative contribution of various activities and appliances to total daily exposure. One hundred sixty-two subjects provided information on their patterns of appliance use and wore personal monitors for 24 h to collect MF exposure data. Of total exposure, 27% accumulated while subjects were in bed; 41% while at home but not in bed; 9% at work; and 24% elsewhere. Less than 2% of the total MF exposure accumulated during the use of each of the eight individual appliances considered, except computers, during the use of which 9% of the total exposure accumulated. Of the time subjects spent at exposure levels higher than 2 microT, 8% accumulated while they were using microwave ovens, and 4% and 3% while using computers and electric stoves, respectively. Mean MF measurements tended to be lowest when subjects were in bed and highest at work and during the use of microwave ovens, coffee grinders, hair dryers, and electric shavers. Results from questionnaires on household appliance use in the past year were not useful in predicting the total mean exposure level and over-threshold exposures measured by 24-h personal monitors. Significant MF exposure accumulates at home, at work, and elsewhere; therefore, accurate exposure assessment needs to consider residential, occupational, and other sources together. Questionnaire-based information on appliance use has limited value in the assessment of average and over-threshold exposure to MFs.

Activities of Daily Living↗

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Elemental diet composition and the structure and function of rat small intestine: comparison of the effects of two diets on morphology and in vivo absorption of water.

The effects of feeding elemental diets on small bowel structure and function in normal rats has been investigated, and two commercial diets Vivonex (#1) and Flexical (#2) compared. Rats were fed Diet #1 (n = 12) or Diet #2 (n = 12) for 1 month and jejunal and ileal histology compared with that of an equal number of rats fed on a normal pelleted diet. Diets #1 and #2 significantly increased villus height and decreased crypt height to villus height ratio in both jejunum and ileum (p less than 0.02 in all cases). Crypt height was also significantly reduced in the ileum but not jejunum by both elemental diets (p less than 0.05 in both cases). Segments of jejunum or ileum were perfused by an in vivo technique and water absorption measured to assess small bowel function. No significant difference in absorption was found between the rats fed Diet #1 and controls but absorption of water was depressed in both jejunum and ileum of those fed Diet #2. Small intestinal absorptive function is thus influenced by the composition of the elemental diet.

Amino Acids↗

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Influence of the intake and composition of elemental diets on bile acid metabolism and hepatic lipids in the rat.

The effects of the elemental diets Vivonex (V) and Flexical (F) on bile acid metabolism and hepatic lipids in the rat has been investigated both with ad libitum feeding and when calorie intake was limited to that of control rats (C) fed a standard diet (Oxoid 41B). Ad libitum feeding of V and F for 9 weeks resulted in a weight gain in excess of that for the control diet. After 9 weeks of isocaloric feeding the V-fed rats were significantly lighter than those fed F and C. Fecal bile acid excretion (FBA) and the fractional turnover rates for cholic acid (CA) and chenodeoxycholic acid (CDC) were measured. The elemental diets significantly reduced FBA when fed both ad libitum and isocalorically compared with the control diet, the reduction with V being significantly greater than for F. In the isocaloric feeding study both elemental diets significantly increased the half life of CA and CDC. The increase for CA was significantly greater for V than F but for CDC the effect of the two diets was the same. Thus the percentage of CDC-derived 6 substituted bile acids was greater with V than F feeding. There was a strong negative correlation between bile acid half-life and fecal excretion of metabolites for the three dietary groups indicating that bile acid pool size was unchanged by the elemental diets. A gross increase in liver lipid both histologically and chemically was found for the ad libitum fed V rats with a marked but lesser increase for F.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

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HMOs in the Medicare market. Part 1.

Final governmental regulations permitting all qualified health maintenance organizations and competitive medical plans to enter the Medicare market were published early last year. This action has created a significant need for information on marketing strategies and operational issues pertaining to this new area. Mathematica Policy Research was awarded a grant by HCFA to evaluate the Medicare Competition Demonstration program undertaken by 26 HMOs and CMPs between August 1982 and December 1984, with a focus on the marketing strategies and operational decisions and changes during the initial period of entering the Medicare market. In this first part of a two-part report, information is provided on the marketing approaches developed by the demonstration HMOs as they dealt with, in most cases, a large influx of elderly enrollees.

Advertising↗

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HMOs in the Medicare market. Part 2--Operational issues.

Explore the source record for details and available documents.

Aged↗

PubMedDate not supplied

Comparison of "rollovers" and "switchers" among enrollees of Medicare HMOs.

Individuals who are able to enroll in an HMO and retain the physician-patient relationship they had developed under fee-for-service arrangements ("rollovers") may differ on average in health status and other characteristics from those who changed physicians to join an HMO ("switchers") and those who did not have a regular physician prior to joining. If such differences exist, they could have important implications for the relative performance of IPA-model HMOs, which tend to enroll significant numbers of rollovers, and staff model HMOs, which primarily enroll switchers and individuals without a regular physician. This study uses survey data on Medicare beneficiaries who enrolled in 17 HMOs under the Medicare competition demonstrations to compare rollovers to both switchers and enrollees who previously had no regular physician. The findings indicate that rollovers are very similar to each of the other categories of enrollees on demographic and socioeconomic characteristics as well as self-reported health status.

Continuity of Patient Care↗

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Helicobacter pylori, pepsinogen, and risk for gastric adenocarcinoma.

The objective of this project was to determine the association of Helicobacter pylori infection and serum pepsinogen levels on subsequent risk for gastric adenocarcinoma. This nested case-control study was set in a large health maintenance organization. One hundred thirty-six cases of gastric adenocarcinoma and 136 matched controls without adenocarcinoma from a large cohort that had contributed serum in the 1960's were studied. The presence of IgG against H. pylori had previously been determined by enzyme-linked immunosorbent assay. Serum levels of pepsinogens I and II were ascertained by radioimmunoassay. In a sample of subjects, the presence of antiparietal cell antibodies was determined by immunofluorescent antibody assay (Nichols Laboratory). There were 98 cases of adenocarcinoma of the antrum, body, or fundus (distal cancers) and 30 of the cardia or gastroesophageal junction (proximal cancers). By univariate analysis, H. pylori infection [odds ratio (OR), 3.6; P < 0.001] and serum pepsinogen I < 50 ng/ml (OR = 2.9; P = 0.003) were both associated with development of distal cancer. In multivariate analysis, there was interaction between the two variables; H. pylori in the absence of low pepsinogen I was independently associated with cancer (OR, 2.4; P = 0.04) but low pepsinogen I in the absence of H. pylori infection was not associated with cancer (OR, 0.8; P > 0.5). In combination, however, H. pylori infection and a low pepsinogen I were associated with a marked increase in the risk of developing distal malignancy (OR, 10.0; P = 0.08).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗

PubMedDate not supplied

Epidemiology of ALS.

Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder of unknown etiology. ALS onset is rare before age 40 and increases with age thereafter. Men are at higher risk than women (ratio 1.3:1). Other than age and gender, the only indisputable risk factor for ALS is genetic susceptibility, with familial cases occurring in about 10% of most case series. Genetic linkage studies have provided evidence that a mutant form of the gene that codes for Cu/Zn superoxide dismutase, an endogenous free radical scavenger, is important in 15-20% of familial cases. Epidemiologic studies have identified associations of sporadic ALS with work in occupations that involve toxicant exposure. Environmental toxicants may act against a background of increased genetic susceptibility; however, genetically acquired biochemical defects have not been identified in sporadic ALS patients. Other epidemiologic theories of disease etiology have emphasized the potential role of physical trauma, electrical shock, and vigorous physical exertion, but evidence regarding these factors is inconsistent.

Adolescent↗