Age-related changes in resting levels of the free intracellular calcium concentration ([Ca2+]i) as well as alterations of the rise in [Ca2+]i following depolarization have been investigated in acutely isolated brain cells of various regions of the rat brain. Characterization of the Ca2+ responses following KCl depolarization in the hippocampus, cortex, striatum, and cerebellum of young rats revealed significant regional differences in the basal [Ca2+]i level as well as in the KCl-induced rise in [Ca2+]i. However, there was no correlation between both parameters. Resting [Ca2+]i as well as Ca2+ responses after depolarization were lower in the hippocampus and cortex of the aged animals, but not in the striatum or cerebellum. It is concluded that the Ca2+ homeostasis in the first two regions is specially susceptible to the aging process, resulting in a downregulation of [Ca2+]i, probably as a consequence of an enhanced sensitivity of mechanisms regulating transmembraneous Ca2+ fluxes. The cellular Ca2+ homeostasis was altered in a comparable way in rat spleenocytes. The rise in [Ca2+]i in the aged animals following stimulation of lymphocytes with the mitogen phytohemagglutinin (PHA) was significantly reduced in the plateau phase, which is maintained by Ca2+ influx mechanisms. The data indicate that age-related disturbances of the cellular Ca2+ homeostasis may be present in different cell types and seem to affect mainly transmembraneous Ca2+ flux much more than intracellular Ca2+ release.

Aging↗

PubMedDate not supplied

Distinct processing of endogenous and overexpressed recombinant presenilin 1.

The presenilin 1 (PS1) gene has been identified by positional cloning. More than 30 mutations were detected in this gene which cosegregate with Alzheimer's disease (AD). Understanding their role in disease pathogenesis requires a characterization of the PS1 protein. We have generated a set of antibodies against the three major hydrophilic domains of the deduced amino acid sequence. Analyzing cultured cells and brain samples, we identified the endogenous PS1 polypeptide as well as amino- and carboxy-terminal fragments. These metabolites were much more abundant than the full-length molecule, indicating substantial processing. Overexpression of human PS1 markedly increased the full-length polypeptide but hardly altered the amount of the metabolites. Instead, additional proteolytic fragments appeared suggesting a different metabolism of the excess PS1, which may impede studies in transfected cells. Our results indicate a tight regulation of the endogenous PS1 metabolites. PS1 and its fragments are shown to be integral membrane proteins of the endoplasmic reticulum. The mechanisms regulating the generation of the metabolites, their potential function, and role in AD remain to be studied.

Blotting, Western↗

PubMedDate not supplied

The influence of income, education, and work status on women's well being.

This article, based on data from the Commonwealth Fund 1998 Survey of Women's Health, examines the relationship between socioeconomic status (SES) and women's health. Women living in poverty are less likely than their higher-income counterparts to have health insurance and use preventive services, and more likely to have access problems, suffer from chronic illnesses, and report low overall health scores. Women with low educational attainment are also less likely to have health insurance and to use preventive services, and more likely to report poorer health status than women with a college education. We conclude with implications for public policy.

Adult↗

PubMedDate not supplied

Rapid target analysis for pesticides in water by online coated capillary microextraction combined with liquid chromatography and tandem mass spectrometry.

The applicability of online trace enrichment with custom-made coated capillaries combined with tandem mass spectrometry was demonstrated for the target analysis of selected pesticides (mainly herbicides, e.g., triazines, phenylureas, and acetanilides) in water. The developed method allows rapid determination of several widely used plant protectants within a total analysis time of 11 min. Good linearity (r > or = 0.995) was obtained for the selected pesticides in the range of 0.050-50 microg/L. The relative standard deviations (RSDs) of the peak areas were < or = 3.8% for spiked Milli-Q water (5 microg/L). The RSDs obtained in analyses of spiked (1 microg/L) water samples (brook water, river water, sewage plant effluent) ranged from 2.9 to 6.8%, indicating low influence of the matrix on enrichment and detection. The detection limits, which ranged from 10 to 90 ng/L, fulfilled the requirements of the European regulations for drinking water. The polyacrylate coating of the extraction capillary showed good stability in the presence of water and acetonitrile and allowed > or = 100 extractions with 1 capillary.

Chromatography, Liquid↗

PubMedDate not supplied

[Influence of changing oral mineral supply on kidney functions including renal fractional excretion of calcium, magnesium and phosphate in cows].

The influence of normal (100%), reduced (50%), or increased doses (200%) of mineral content in food on selected kidney functions and on serum values of calcium, magnesium, phosphate and osmolality was tested in cattle (n = 6; age: 3-5 1/2 years; metabolic body mass: 106-132 kg0.75; non-pregnant, non-lactating) over 7 weeks. During the 19-day period of reduced mineral supply glomerular filtration rate, urine osmolality, 24-hour urine creatinine amount and serum electrolyte concentrations (exception: total magnesium) remained without significant deviations from the initial physiological values. In contrast to these results, the values of 24-hour urine volume, 24-hour urine osmolyte, serum/urine-ratio of creatinine, FECa and FEMg were significantly reduced. During the 15-day feeding period with over-supply of minerals the parameters 24-hour urine volume, serum/urine-ratio of creatinine, FECa, FEMg and FEPhosphate rose significantly. The proven influence of the supply with minerals on the renal electrolyte elimination can be used for the diagnosis of disturbances of mineral-feeding in "kidney-healthy" cattle.

Animal Feed↗

PubMedDate not supplied

The use of reverse-phase chromatographic procedures coupled with radioimmunoassay in studying regional distribution of beta h-endorphin in the human brain.

Fast reverse-phase chromatographic procedures (Sep-Pak C18 cartridges and high pressure liquid chromatography) combined with radioimmunoassay is presented. It provides accurate assessment of brain tissue concentrations of beta h-endorphin (beta h-E). The method was used to study the distribution of the endogenous opioid in nine distinct human brain regions. The beta h-E was found mainly localized in the hypothalamus anterior, hypothalamus posterior followed by a lower concentration in the Corpora mamillaria and the Substantia grisea centralis. Concentrations below 1.0 fmol/mg fresh brain tissue were determined in the Pons dorsalis, Substantia nigra, Colliculi inferiores, Glandula pinealis and in Nucleus ruber.

Brain Chemistry↗