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Biomedical subjects

D A Smith

Publications and source records attributed to D A Smith.

At least 289 records · Page 16Linked to original sources
PubMed1987

Overurbanization reconceptualized: a political economy of the world-system approach.

"After many years of relative neglect, the issue of 'overurbanization' in Third World countries has recently received renewed attention in the social science literature. Adopting a political economy of the world-system perspective on urbanization and development, this article critiques the theoretical adequacy of the overurbanization thesis. Conceptualizing a causal relationship between spatio-demographic imbalances (labelled 'over-urbanization') and relatively skewed and stagnant economic development is midleading. Both urban patterns and development trajectories are distorted by the international dependency of Third World nations in the world economy. The general argument is illustrated by discussing the role that the so-called 'urban surplus labor' of the 'informal sector' plays in surplus extraction under peripheral capitalism."

Demography↗
PubMed1987

Treating hyperlipidemia, Part III: Drug therapy.

In elderly patients at increased risk for cardiovascular disease due to lipid abnormalities, numerous medications are available for altering such abnormalities. Most of these drugs have side effects which, in the elderly, may necessitate lower dosing than usual. For persons with severe elevations of triglycerides, nicotinic acid (Niacin) and gemfibrozil (Lopid) may be used. For those who need a reduction in the LDL cholesterol, choices include bile acid-binding resins, nicotinic acid, HMG CoA reductase inhibitors, probucol (Lorelco), and neomycin.

Aged↗
PubMed1987

Treating hyperlipidemia, Part I: Whether and when in the elderly.

There are elderly persons at increased risk of coronary heart disease due to elevated LDL cholesterol, lowered HDL cholesterol, or both. Risk difference data seem to indicate that the reduction in risk of coronary artery disease by lowering elevated cholesterol values is the same in the elderly as it is in younger persons. hence we recommend screening for total cholesterol in the elderly, followed by a fasting lipid profile in those with screening cholesterol values over 200 mg/dl (230 mg/dl by certain methods). Comparative LDL and HDL cholesterol values, as well as L/H ratios, are presented for assisting in assessment of results and for planning therapeutic strategy.

Aged↗
PubMed1987

Treating hyperlipidemia, Part II: Making dietary control work in the elderly.

Changing lifestyle behaviors and eating habits are the most important recommendations a physician can make in controlling adverse lipid levels in the elderly. One may improve HDL cholesterol levels through encouraging smoking cessation, ideal weight maintenance, and aerobic exercise. This article discusses new dietary recommendations for lowering LDL cholesterol and provides a table of dietary tips for patients.

Aged↗
PubMed1987

Determination, by radioimmunoassay, of the mass of lactate dehydrogenase isoenzyme 1 in human serum and of its rate of removal from serum after a myocardial infarction.

In this radioimmunoassay of lactate dehydrogenase-1 (LD-1; EC 1.1.1.27) in human serum we use a commercial LD-1-selective assay system and a goat antiserum. We have determined the fractional rate of disappearance from serum and the half-life of LD-1, in terms of both enzyme activity and enzyme mass, in 21 myocardial infarction patients. Our evidence suggests that this isoenzyme is inactivated in serum. Furthermore, our data suggest that the conventionally accepted half-life of about 110 h for serum LD-1 activity may grossly overestimate the actual LD-1 half-life in many post-myocardial infarction patients.

Half-Life↗
PubMed1987

The scarlet letter.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1986

O-phosphohomoserine, a naturally occurring analogue of phosphonate amino acid antagonists, is an N-methyl-D-aspartate (NMDA) antagonist in rat hippocampus.

O-Phosphohomoserine, an analogue of the excitatory amino acid antagonist 2-amino-phosphonovalerate, has been synthesized and tested for activity as an excitatory amino acid antagonist. The tests were carried out on 500 micron thick slices of rat hippocampus superfused in vitro at 30 degrees C. Antidromic and orthodromic potentials were studied in the CA1 region, recording from the pyramidal cell layer. At concentrations of 0.5 and 1 mM the compound produced a weak but significant antagonism of the depression of evoked potentials produced by N-methyl-D-aspartate with no effect on the responses produced by kainic or quisqualic acids. O-Phosphohomoserine was not metabolised by brain homogenates or by alkaline phosphatases. Since O-phosphohomoserine is known to occur naturally in lower organisms, it would be of interest to seek its existence in the animal nervous system.

Animals↗
PubMed1986

Pulmonary function in chronic renal failure patients managed by continuous ambulatory peritoneal dialysis.

The influence of intraperitoneal fluid on pulmonary function was studied in 20 unselected continuous ambulatory peritoneal dialysis (CAPD) patients, all but one of whom had at least one cardiorespiratory disorder. Measurements of pulmonary function were made with the abdomen empty and following the instillation of 2 1 of dialysis fluid (full). Functional residual capacity fell with the peritoneal cavity full, due to decreases in residual volume, and expiratory reserve volume, but there was a corresponding increase in inspiratory capacity. The vital capacity remained unchanged and the total lung capacity fell only slightly. The FEV1, diffusing capacity, and distribution of ventilation were unaltered. These findings can be attributed to an increase in intra-abdominal pressure resulting in elevation of the diaphragm and increased diaphragmatic contractility. We conclude that the instillation of 21 of dialysis fluid in CAPD patients with cardiorespiratory disease does not result in a clinically significant deterioration in these aspects of pulmonary function.

Adult↗
PubMed1986

Postsynaptic action of kynurenic acid in the rat dentate gyrus.

Quantal analysis was performed on excitatory postsynaptic potentials (EPSP) recorded with intracellular electrodes from granule cells of the rat dentate gyrus, before, during and after the iontophoretic application of kynurenic acid. In this way a reduction in the EPSP caused by kynurenic acid was shown to be accompanied by an appropriate reduction in quantal size whilst the average number of quanta released per impulse was unchanged. The reduction in quantal size parallelled the reduction in the amplitude of the EPSP and is thus consistent with an action of kynurenic acid at a postsynaptic site. In addition, on a number of cells kynurenic acid reduced the depolarization evoked by L-glutamate by an equivalent amount and it is thus proposed that the synaptic transmitter is glutamate-like.

Animals↗