Attempts to establish experimental Cyclospora cayetanensis infection in laboratory animals.

Attempts were made to develop an animal model for Cyclospora cayetanensis to identify a practical laboratory host for studying human cyclosporiasis. Oocysts collected from stool of infected humans in the United States, Haiti, Guatemala, Peru, and Nepal were held in potassium dichromate solution to allow development of sporozoites. The following animal types were inoculated: 9 strains of mice, including adult and neonatal immunocompetent and immune-deficient inbred and outbred strains, rats, sandrats, chickens, ducks, rabbits, jirds, hamsters, ferrets, pigs, dogs, owl monkeys, rhesus monkeys, and cynomolgus monkeys. Most animals were inoculated by gavage, although some of the primates were fed oocysts on food items. The animals were examined for signs of infection, particularly diarrhea, and stool samples were examined for 4-6 wk after inoculation. None of the animals developed patent infections or signs of infection. We conclude that none of the animals tested is susceptible to infection with C. cayetanensis.

1985 NHIS findings: nutrition knowledge and baseline data for the weight-loss objectives.

A nutrition objective for the nation is that, by 1990, 50 percent of the overweight population should have adopted weight regimens, balancing diet and physical activity. More than half of the overweight respondents in the 1985 National Health Interview Survey were trying to lose weight, and almost half of this group reported both increasing their physical activity and decreasing their intake of calories. Dietary restriction without exercise was the next most common weight-loss regimen, suggesting that educational efforts should emphasize the need to increase physical activity as part of appropriate weight-loss regimens. Attempts to lose weight were reported frequently among those of normal and lean weight as well as among those who were overweight, especially among women and the better educated. About one-fifth of already lean young women reported attempting weight loss, an indication that some inappropriate dieting is probably occurring, suggesting the need for caution in public health promotion of weight loss. Another 1990 objective is that 90 percent of adults should understand that eating fewer calories or increasing activity, or both, is essential to lose weight. More than 70 percent of adults in this survey were able to identify these as the two best ways to reduce weight, with greater proportions of the younger adults and the more highly educated being knowledgeable. The survey also provided data for an objective that targets some nutrition education and counseling as part of all routine health contacts with health professionals by 1990. Twenty-nine percent of all women and 22 percent of all men reported that eating proper foods was discussed sometimes or often in routine contacts.

A rational approach to decision making in toxicology.

The application of the Kepner-Tregoe (C. H. Kepner and B. B. Tregoe, 1981, The New Rational Manager, Princeton Res. Press, Princeton, N. J.) problem solving technique to the evaluation and interpretation of toxicological information is described. Data from a chronic study provide an illustrative example. In this study an excess in the number of urinary bladder neoplasms was observed in male rats exposed to diets containing the test chemical. No similar effect was seen in treated female rats. Both male and female mice exposed to treatment also exhibited no effect. Whether treatment was the cause of the observed increase should be based on all the scientific and technical information that is relevant to this decision. The Kepner-Tregoe method of problem analysis captures this information in a framework that makes it easily understood. This is especially desirable if the judgments that are a vital part of regulatory decision making are to be adequately communicated.

The significance of morphometric procedures in the investigation of age changes in cytoarchitectonic structures of human brain.

The investigations were performed on NISSL-stained cytoarchitectonic images of totally 78 human brains (aged between 18 and 111 years) in the frontal area 11 (inside sulcus olfactorius) with 60 samples and in the visual cortex (area 17) with 45 samples. The morphometric measurements were taken by using a semiautomatic equipment. The largest projection areas of neurons were digitized over a drawing mirror. The arrangement of fields made it possible to get values for the total cortex and its layering. During the calculation the age-dependent embedding shrinkage was paid attention to. Therefore, the values concern the fresh tissue. The neuronal and glial densities, the neuronal sizes and size-distributions were calculated by using stereological and statistical principles. The results outline the following points: A basic description of the cytoarchitectonics is given in their qualitative and quantitative aspects. The individual variation shows high differences, which however, are in accordance with a normal statistical distribution. In area 11 we could find a significant difference of neuronal densities between males and females. The cell-sizes and the aging behavior are not different. In area 17 the amount of female brains was too small for statistics. The aging of both areas showed that the densities of neurons and glial cells do not decrease. A small increase may be possible. The neuronal sizes of area 11 are constant up to 60 years, then a distinct decrease can be observed. During aging the size decrease of neurons is very small in area 17. The layer III usually shows a distinct decrease of neuronal size during aging while layer V has a nearly constant size. The results were discussed and compared with other publications. The differences between our results and earlier publications seem to be mainly due to methodical problems. The older papers do and could probably not observe the stereological procedures of measuring and the age differences of the embedding procedures. The main result is that every gray structure of the brain has its own history.

Experiments with the aim of a more exact division of a layered tissue in stereological investigations.

Investigations concerning cell densities and projection areas in layered tissues, which use the procedures published by Haug, are burdened with problems due to the division of the layers and the dependence on the size of the evaluation field. In order to find a more exact division, we used a modified microscopic field. Experiments show that a circular field has no advantage as compared with a quadratic field. Therefore, the circular field cannot be recommended.

The aging of cortical cytoarchitectonics in the light of stereological investigations.

With the help of stereological procedures quantitative results concerning the aging of the human cortex could be found. 1. Older brains shrink less during the histological treatment than younger ones. 2. The neuronal density does not change in all four estimated areas (Brodman 6, 7, 11, 17). 3. In two areas (frontal lobe) a statistical significant decrease of neuronal cell size could be found. The conclusion allows the statement that the various parts of cortex age differently.

Gas-liquid chromatographic determination of mono- and diiodotyrosines in serum.

A sensitivie, reliable gas-chromatographic assay for monoiodotyrosine and diiodotyrosine in human serum is reported. The oxazolidinone-heptafluorobutyric anhydride derivatives allow the quantitation of both compounds in the linear range of 0.2 to 7.6 mg/L of serum. Analytical recovery averaged 88%, and mean accuracy and within-run precision were 98 and 2%, respectively. Concentrations of monoiodotyrosine in serum as low as 20 microgram/L and of diiodotyrosine as low as 100 microgram/L can be detected. Normal serum contains no detectable concentration of either compound, but the method is applicable as a diagnostic tool in the early prediction of thyroid disease. Both compounds were detected in the serum of a hypothyroid subject whose normal thyroid hormone concentrations were being maintained by therapy with desiccated thyroid extract.

Assessment of third trimester choline phosphotransferase activity in uncomplicated human pregnancies.

CDP--choline:1,2-diglyceride choline phosphotransferase (CPT; EC 2.7.8.2) undergoes a marked surge in activity in human amniotic fluid when assayed from 30 weeks of gestation to term. The activity of this enxyme, plotted against gestational age, follows a highly significant regression correlation from which an equation can be obtained for the prediction of gestational age.