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Biomedical subjects

M Haines

Publications and source records attributed to M Haines.

32 records · Page 2Linked to original sources
PubMed1989

Variation in buoyant density of whole cells and isolated cell walls of Streptococcus faecium (ATCC 9790).

The buoyant density of whole cells of Streptococcus faecium varies with growth rate and during the cell cycle. Two possible explanations for this were explored: (i) the density of cell walls may vary, and (ii) the proportions of wall and cytoplasm may vary. We tested the first possibility by isolating walls from chilled, unfixed populations of S. faecium cells and fractionating them on Percoll density gradients. Mean cell wall density averaged 4% less than whole-cell density and did not vary significantly with growth rate. In addition, walls isolated from heavy and light fractions of a population of cells did not differ significantly in density. Thus, variation in the density of isolated cell walls could not account for the observed variation in whole-cell density within or between populations. Using previously published measurements of the physical dimensions of S. faecium cells, we also found that the relative proportions of wall and cytoplasm (see the second possibility above) could not account for the observed changes in whole-cell buoyant density.

Cell Wall↗
PubMed1976

Cardiorespiratory effects of outpatient anesthesia for oral surgery: trichloroethylene-halothane.

The cardiorespiratory effects of trichloroethylene supplementation of nitrous oxide-oxygen anesthesia, with simultaneous use of halothane at induction as needed, were studied in outpatient oral surgery patients undergoing dental extractions under general anesthesia. The technique produced no deleterious cardiovascular effects that could be attributed to the combined use of these agents. Elevations of blood pressure, stroke volume, and peripheral resistance indicated light anesthesia. The versatility of halothane combined with the absence of nephrotoxic and hepatotoxic breakdown products of trichloroethylene provides a satisfactory technique for outpatient oral surgery. The agents appear pharmacologically complimentary in that halothane lacks analgesic properties and postoperative shivering occurs, while induction with trichloroethylene is slow and tachypnea is a problem.

Adolescent↗
PubMedDate not supplied

Noise and health in the urban environment.

Noise, including noise from transport, industry, and neighbors, is a prominent feature of the urban environment. This paper reviews the effects of environmental noise on the non-auditory aspects of health in urban settings. Exposure to transport noise disturbs sleep in the laboratory, but generally not in field studies, where adaptation occurs. Noise interferes with complex task performance, modifies social behavior, and causes annoyance. Studies of occupational noise exposure suggest an association with hypertension, whereas community studies show only weak relations between noise and cardiovascular disease. Aircraft and road-traffic noise exposure are associated with psychological symptoms and with the use of psychotropic medication, but not with the onset of clinically defined psychiatric disorders. In carefully controlled studies, noise exposure does not seem to be related to low birth weight or to congenital birth defects. In both industrial studies and community studies, noise exposure is related to increased catecholamine secretion. In children, chronic aircraft noise exposure impairs reading comprehension and long-term memory and may be associated with increased blood pressure. Noise from neighbors causes annoyance and sleep and activity interference health effects have been little studied. Further research is needed for examining coping strategies and the possible health consequences of adaptation to noise.

Adolescent↗
PubMedDate not supplied

Children's cognition and aircraft noise exposure at home--the West London Schools Study.

The association of aircraft noise exposure with cognitive performance was examined by means of a cross-sectional field survey. Two hundred thirty six children attending 10 primary schools around Heathrow Airport in west London were tested on reading comprehension, immediate/delayed recall and sustained attention. In order to obtain the information about their background, a questionnaire was delivered to the parents and 163 answers were collected. Logistic regression models were used to assess performance on the cognitive tests in relation to aircraft noise exposure at home and possible individual and school level confounding factors. A significant dose-response relationship was found between aircraft noise exposure at home and performance on memory tests of immediate/delayed recall. However there was no strong association with the other cognitive outcomes. These results suggest that aircraft noise exposure at home may affect children's memory.

Aircraft↗
PubMedDate not supplied

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Humans↗