Affinity labelling of the folate-binding protein in pig intestine.

A specific transport system for folate and a high-affinity folate-binding protein have been identified in pig intestinal brush-border membranes. To determine if the binding protein plays a role in folic acid (PteGlu) uptake in to the cell, the inactivation of folate binding and transport by N-hydroxysuccinimide esters of folic acid (NHS-PteGlu) was compared. In addition, the number of brush-border proteins modified by the affinity reagent was assessed.

California's Proposition 65: extrapolating animal toxicity to humans.

In 1986, the voters of California passed a law regarding the concept of extrapolating animal toxicity data to humans. The California Safe Drinking Water and Toxic Enforcement Act of 1986, known as Proposition 65, does five things: 1. It creates a list of chemicals (including a number of agricultural chemicals) known to cause cancer or reproductive toxicity; 2.

Occupational health among migrant and seasonal farmworkers: the specific case of dermatitis.

Occupational health studies of agricultural workers have generally excluded migrant and seasonal farmworkers, and this population experiences a high degree of health risk from agricultural exposures. A survey of dermatologic disorders among migrant and seasonal farmworkers will be used to illustrate this point. Data from a recent field study are presented to illustrate epidemiologic approaches to studying dermatologic disorders in farmworkers and risk factors for dermatitis.

Oxidant stress inhibits the endogenous production of lipoxygenase metabolites in rat lungs and fish gills.

Hydroperoxides are potent initiators of lipid peroxidation in vivo. Acyl hydroperoxides may also regulate various aspects of lipid metabolism. In this study we investigated the regulation of the endogenous 12 lipoxygenase in trout gill and rat lung, a prominent acyl hydroperoxide catalyst in these tissues.

Accumulation and regulation of elastin in the rat uterus.

The relative levels of elastin-specific mRNA were used as a measure of tropoelastin expression in uteri from pregnant Sprague-Dawley rats. The levels of elastin-specific mRNA were also correlated with values for net tropoelastin production and net deposition of mature, crosslinked elastin. The total content of uterine elastin increased throughout gestation, reaching maximal levels at Day 19 of gestation, which were three times those of nongravid tissue.

The economic costs of alcohol abuse: an assessment of current methods and estimates.

This article provides an exposition and critical review of the methods and assumptions used by the National Institute on Alcohol Abuse and Alcoholism to estimate the economic costs of alcohol abuse. Particular attention is paid to the methods used to estimate productivity loss which comprises over half of total abuse costs. This study concludes that these estimates are inaccurate and that they continually overstate actual costs.

Increased Na+-taurine symporter in rat renal brush border membranes: preformed or newly synthesized?

The renal adaptive response to a varied intake of sulfur amino acids is demonstrated by an increase in the initial rate of Na+-taurine symport (cotransport) by rat renal brush border membrane vesicles (BBMVs) after 8-14 days of a low methionine diet. A high (3%) taurine diet reduces Na+-taurine symport. Fasting for 3 days, which depletes renal tubule cell taurine content, also enhances Na+-taurine symport both initially (15 s) and throughout the overshoot.

Mode of inheritance of Perthes' disease in Manchester terriers.

A test mating between two Manchester Terriers affected by Perthes' disease (PD) resulted in the birth of three affected males and two unaffected females. In the three puppies with PD, roentgenographically detectable changes in the affected femurs were observed two to three weeks before the onset of lameness and muscle atrophy in the corresponding limb. Analysis of the related pedigrees and of the results of the test mating indicated that PD is an inherited condition with high heritability.

Current status of immunoscintigraphy in the detection of thrombosis and thromboembolism.

This review describes the use of monoclonal antibodies (MoAbs) for immunoscintigraphic detection of thrombosis and thromboembolism. Two major groups of MoAbs have been tested: Antibodies directed against platelets and antibodies directed against fibrin. Several antiplatelet antibodies have been developed that are directed against either the platelet membrane glycoprotein complex, IIb/IIIa, which binds fibrinogen, or against two different proteins, alpha granule membrane protein GMP-140 and thrombospondin (TSP) that are expressed during platelet activation.

Association of Reoviridae particles in an enteric syndrome of poults observed in turkey flocks during 1988.

An enteric syndrome of turkey poults, characterized by enteritis, crop mycosis, intestinal changes (pale, thin-walled ballooning with watery contents), and rickets, occurred during 1988 in 74 turkey flocks from different farms belonging to 9 California turkey growers. The flocks ranged in size from 9,000 to 120,000 birds. Pools of intestine sections from 618 birds, representing 78 field cases, were examined.

Progressive inflammatory and structural changes in the pulmonary vasculature of monocrotaline-treated rats.

The progression of changes in the bronchus-associated and intraacinar pulmonary arteries of rats treated with a single dose of monocrotaline (60 mg/kg) was evaluated by quantitative light and electron microscopy. The relative volume of vessel wall components was normalized to the surface area of the adventitial sheath. An increased relative volume of media was evident in intraacinar pulmonary arteries by 4 hr post-treatment.

Human cervical mucus and its interaction with sperm: a fine-structural view.

Cervical mucus is a glycoprotein gel whose biological functions depend upon its macromolecular architecture. Using freeze-substitution fixation techniques, we have used transmission electron microscopy to examine the fine structural aspects of mucus, before and after unidirectional physical shearing, and during its interaction with sperm. The microstructure of mucus that has not been directionally stretched consists of a homogenous pattern of interconnecting electron-dense elements.

Monitoring of metabolic responses of intact Haliotis (abalones) under salinity stress by 31P surface probe localized NMR.

Surface probe localized 31P NMR spectroscopy was employed to record the metabolic responses of the foot of intact Haliotis cracherodii and H. rufescens (black and red abalones) under hyper- and hypoosmotic stresses. Use of the surface probe allowed spectral localization on the foot of intact abalones, facilitated monitoring of different sizes of animals, and minimized constraints on aquatic chamber design normally imposed by homogeneous-field probes.

A single base pair change in proline biosynthesis genes causes osmotic stress tolerance.

A single base pair change has been found in a site corresponding to a regulatory region of the first enzyme in the proline biosynthetic pathway. This change alters feedback inhibition and is responsible for the synthesis of high levels of proline that enable Escherichia coli to withstand osmotic stress.

Regulation of carbon flow in Selenomonas ruminantium grown in glucose-limited continuous culture.

We have applied a model that permits the estimation of the sensitivity of flux through branch point enzymes (D. C. LaPorte, K.

Proline-rich proteins and glycoproteins: expression of salivary gland multigene families.

Our recent research interests have focused on a group of unusual proteins and glycoproteins high in proline content, or the so-called proline-rich proteins (PRPs). The PRPs are tissue-specific expressions of salivary gland multigene families. Normally PRPs are not detected or are present in very low amounts in rat, mouse and hamster salivary glands, but these unusual proteins are dramatically induced by treatment with the catecholamine isoproterenol.

Pathway and sites for energy conservation in the metabolism of glucose by Selenomonas ruminantium.

On the basis of enzyme activities detected in extracts of Selenomonas ruminantium HD4 grown in glucose-limited continuous culture, at a slow (0.11 h-1) and a fast (0.52 h-1) dilution rate, a pathway of glucose catabolism to lactate, acetate, succinate, and propionate was constructed.

Failure of norepinephrine to initiate porcine malignant hyperthermia.

Continuous intravenous infusion in pigs of norepinephrine, to blood concentrations of 140 ng.ml-1, provided a test of the hypothesis that this sympathetic hormone can initiate malignant hyperthermia (MH). This study was performed during nitrous oxide-pentobarbital anesthesia, and in part utilized sodium nitroprusside to maintain normal blood pressure and peripheral perfusion.

Aldosterone reverses potassium-induced food aversions in adrenalectomized rats.

Young adult male rats were individually housed and given a standard ration (66 ml) of a liquid diet (Nutrament) each day. The animals were divided into 7 groups: five groups were bilaterally adrenalectomized (ADX) and given one of 5 doses of aldosterone and/or dexamethasone by continuous, osmotic minipump infusions. The remaining two groups served as intact and sham operated controls.

Exposure to lindane and two other hexachlorocyclohexane isomers increases free intracellular calcium levels in neurohybridoma cells.

NCB-20 neurohybridoma cells were exposed to isomers of hexachlorocyclohexane (HCH) for periods of time ranging from 5-45 min, and intracellular free calcium [Ca++]i levels were determined using the INDO1/AM method. Exposure to lindane (gamma HCH) produced a dose-dependent increase in [Ca++]i, significant increases being observed with exposures from 10-400 microM. During exposure, [Ca++]i increased to a peak and then declined over the next 45 min.