Developmental changes in lactase-phlorizin hydrolase precursor isoforms in the rat.

The purpose of this study was to determine whether the developmental decline in lactase specific activity (mumol/min/g protein) in the rat was associated with (a) changes in the relative quantities of immunoisolated precursor and mature forms of the enzyme purified by SDS-PAGE and/or (b) immunohistologic changes in the jejunal mucosa. We studied 10- and 16-day-old suckling rat pups, 22-day-old weaned rat pups, and adult female rats (nongravid, pregnant, and lactating). Lactase activity was three- to fourfold higher in 10-day-old pups than in adult rats. Lactase activity was 27% greater in lactating compared with nongravid or pregnant rats. Three molecular forms of the enzyme that migrated identically in all animals were observed on SDS-polyacrylamide gels stained with Coomassie blue: 140-kDa (mature brush border form), 200-kDa, and 220-kDa (apparent precursor forms). There was a striking difference in the proportions of the three polypeptides at different ages that was unrelated to animal status, i.e., pregnant or lactating. As the animals aged, the relative amount of the 140-kDa band declined from 86 +/- 1.1% of the total immunoprecipitated lactase in 10-day old suckling pups to 68 +/- 0.7% in adults. Simultaneously, the relative concentration of the 200-kDa band rose from 1.7 +/- 0.4% in the 10-day-old to 19 +/- 0.6% in adults. The relative concentration of the 220-kDa polypeptide did not change as a function of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebrospinal fluid protein and opening pressure in idiopathic intracranial hypertension (pseudotumor cerebri).

We studied the relationship between the CSF protein concentration and the degree of elevation of the CSF opening pressure in 177 patients with idiopathic intracranial hypertension (pseudotumor cerebri). There was no linear correlation between the CSF protein and opening pressure. In addition, low CSF protein (less than 20 mg/dl) was present in only 26% of the patients. Our findings fail to confirm previous reports of an inverse relationship between the CSF opening pressure and CSF protein as well as low CSF protein in these patients.

A risk assessment for acrylonitrile in consumer products.

A carcinogenic risk assessment for acrylonitrile in consumer products was prepared as part of the Second Workshop on Pragmatics of Risk Assessment, Bethesda, MD. Data from one inhalation and two oral rat bioassays served as input into several high-to-low-dose mathematical risk extrapolation models. The final unit risk estimates for humans were based on maximum likelihood estimates from the Global83 implementation of the multistage model after adjustments for surface area differences, continuous versus intermittent exposures, and the proportion of lifetime exposed. The unit risk estimates for lifetime exposure to 1 mg kg-1 day-1 by inhalation and ingestion were 0.0531 and 0.2385, respectively. These risks are equivalent to risks of 3.3 x 10(-8) for inhalation of 1 ppt in air and 3.4 x 10(-9) for ingestion of 1 ng day.-1

Anthropometric parameters of schoolchildren with different life-styles.

Height and weight data obtained from a 2-year longitudinal survey were analyzed for 2272 children aged 6 through 18 years who were attending public schools or Seventh-Day Adventist (SDA) schools in southern California. The SDAs do not use alcohol or tobacco, and many adhere to a lacto-ovovegetarian diet. For both sexes, in each school group, the mean height and weight were at or above national reference values. Age-adjusted regression analysis showed that SDA school-boys were 1.6 cm taller than public schoolboys. There were no significant differences in height for girls. After controlling for height, boys and girls in the SDA schools were found to be leaner than their public school peers, ie, 1.27 and 1.16 kg, respectively. These results suggest that a health-oriented life-style in childhood and adolescence, such as the one followed by SDAs, is compatible with adequate growth and associated with a lower weight for height.

Treatment of visual loss in pseudotumor cerebri associated with uremia.

Ten patients with pseudotumor cerebri associated with renal insufficiency had papilledema and elevated intracranial pressure, but neurologic examinations and CT were normal. The 40% frequency of severe visual loss, 20/100 or worse, was higher than expected for pseudotumor cerebri. While furosemide was effective in 3 patients with renal transplants, administration of corticosteroids to 2 other patients did not halt progressive loss of vision. The visual function of 2 patients deteriorated even after lumboperitoneal shunting. Five patients underwent fenestration of the optic nerve sheath. This procedure improved the visual acuity of 3 patients and stabilized vision in the others. While the pathogenesis of pseudotumor cerebri in renal insufficiency is unknown, optic nerve sheath fenestration is the surgical treatment of choice for visual loss unresponsive to medical therapy.

Bone mineral content in postmenopausal women: comparison of omnivores and vegetarians.

This cross-sectional study of bone mineral content (BMC)/bone width (BW) (BMC/BW, cortical radius) was conducted in elderly, free-living Methodist omnivores (n = 146) and Seventh-day Adventist vegetarians (n = 144) in southern California. The purpose was to investigate relationships between BMC/BW and dietary factors (primarily vegetarianism and intakes of protein and calcium) and use of prescribed drugs. BMC was measured by single-photon absorptiometry. Dietary intakes during current and early periods of life were assessed by 24-h dietary recall and frequency methods. Information about drug use was obtained by interview. BMC/BW was not different in omnivores vs vegetarians. There were no significant relationships or trends between current or early dietary intakes and BMC/BW in either group. In multiple-regression analysis, age, weight, and use of estrogen and thiazide diuretics were predictive of 31% of the variability in BMC/BW in the total group.

Counseling the pregnant vegetarian.

Underlying any successful counseling effort must be an understanding of the acceptable and unacceptable foods of the particular person being counseled, with the recognition that nutrient needs may be met in many ways. This knowledge base necessary for successful counseling along with an understanding of other lifestyle practices that may have an impact on health will be difficult to develop unless rapport is established. Nonjudgmental, accepting attitudes on the part of the health professional are essential to the development of relationships with those individuals who may be suspicious of traditional medical and health-care practices. Strategies for counseling with particular attention to the vegetarian are noted.