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Biomedical subjects

S White

Publications and source records attributed to S White.

At least 235 records · Page 13Linked to original sources
PubMed1990

Assessment of community health aides.

A research project funded by the Commonwealth Caribbean Medical Research Council (CCMRC) began in February 1987, to study aspects of the situation in connection with 508 Community Health Aides (CHAs) employed in the Government Service of Jamaica. There were in the service 1,328 CHAs in 1978, reduced to 1,183 in 1982 and to 1,168 in 1984. By 1985/86 the numbers were further reduced, reaching the low figure of 508. This report deals specifically with the responses of 615 members of the community who were interviewed, and questionnaires were returned from all parishes in the four Administrative Health areas in Jamaica. The responses from community members are very important in the assessment of community health aides as members of the community health team. A number of useful and practical suggestions were reflected in their responses regarding service from community health aides.

Community Health Services↗
PubMed1990

Survey of community health aides in Jamaica (1987-1988).

The Community Health Aide (CHA) programme was initiated in 1967, and, by the early 1980s, 1,328 CHAs had been trained and over 1,100 remained in the service. The aim of the programme was to train CHAs to assist in the delivery of basic health care. During the restructuring of the health services in 1985-1986, many CHAs were made redundant. As part of a large study aimed at assessing the current status of the CHA programme, this paper reports results of interviews with 415 CHAs still in service in 1987-1988 and 134 CHAs no longer employed in the programme at that time. The survey of CHAs still employed as such showed that they continued to perform duties in the community and in health centres with emphasis on the maternal and child health services and the management of diabetics and hypertensives. The survey of CHAs no longer employed as such showed that the majority remained unemployed through many continued to use their skills on a voluntary basis. These CHAs felt that home visiting had been reduced and environmental health was being neglected since they left, and that problems were not being regularly reported to the professionals at the health centres. It was recommended that all CHAs be offered training in the taking of blood pressure levels and in the giving of insulin injections to diabetics. Recommendations included improved methods of selection, longer training, greater community outreach, especially to the elderly, post-training evaluation, regular assessment of the CHAs' performance, and improved upward mobility opportunities and job security.

Adult↗
PubMed1989

Tricho-rhino-phalangeal and branchio-oto syndromes in a family with an inherited rearrangement of chromosome 8q.

Here we report on a family with an inherited rearrangement of chromosome 8q, dir ins(8)(q24.11q13.3q21.13). Individuals with the chromosome abnormality, which does not appear to be associated with deletion of chromosome material, have manifestations of both tricho-rhino-phalangeal syndrome (TRPS) and branchio-oto syndrome (BOS). TRPS has been linked previously to deletions involving 8q24.11----q24.13, but none of the described patients with deletions in this part of 8q have had characteristics of the BOS. The presence of a breakpoint in 8q24.11 without apparent chromosome deletion in the family described suggests that TRPS maps to this band of 8q. Further, it is suggested that BOS maps to either 8q13.3 or 8q21.13.

Abnormalities, Multiple↗
PubMed1989

Mechanism of aldosterone-induced increase of K+ conductance in early distal renal tubule cells of the frog.

Isolated early distal tubule cells (EDC) of frog kidney were incubated for 20-28 hr in the presence of aldosterone and then whole-cell K+ currents were measured at constant intracellular pH by the whole-cell voltage-clamp technique. Aldosterone increased barium-inhibitable whole-cell K+ conductance (gK+) threefold. This effect was reduced by amiloride and totally abolished by ouabain. However, aldosterone could still raise gK- in ouabain-treated cells in the presence of furosemide. We tested whether changes in intracellular pH (pHi) could be a signal for cells to regulate gK+. After removal of aldosterone, the increase in gK+ was preserved by subsequent incubation for 8 hr at pH 7.6 but abolished at pH 6.6. In the complete absence of aldosterone, incubation of cells at pH 8.0 for 20-28 hr raised pHi and doubled gK+. Using the patch-clamp technique, three types of K+-selective channels were identified, which had conductances of 24, 45 and 59 pS. Aldosterone had no effect on the conductance or open probability (Po) of any of the three types of channels. However, the incidence of observing type II channels was increased from 4 to 22%. Type II channels were also found to be pH sensitive, Po was increased by raising pH. These results indicate that prolonged aldosterone treatment raises pHi and increases gK+ by promoting insertion of K+ channels into the cell membrane. Channel insertion is itself triggered by raising both pHi and increasing the activity of the Na+/K+ pump in early distal cells of frog kidney.

Aldosterone↗
PubMed1989

Effect of prolonged hypoxemia on fetal heart rate accelerations and decelerations in sheep.

Experiments were conducted in 10 chronically catheterized fetal sheep to determine the effect of 24 hours of hypoxemia in the absence of progressive acidemia on fetal heart rate accelerations and decelerations. Fetal hypoxemia was produced by mechanically restricting uterine blood flow with a vascular clamp placed around the maternal common internal iliac artery. Fetal arterial oxygen tension decreased from 22.3 +/- 1.8 to 17.8 +/- 1.5 mm Hg at 2 hours and remained low for the 24-hour experimental period. Fetal pH decreased from 7.34 +/- 0.01 to 7.20 +/- 0.05 at 2 hours and returned to normal values by 12 hours. No significant change was observed in the number or characteristics of fetal heart rate accelerations or decelerations during the 24-hour control period. There was a significant increase in the number of accelerations from 48 +/- 4 to 63 +/- 4 per hour at 8 hours of hypoxemia followed by a return to control values by 12 hours. There was no significant change in the mean amplitude or duration of accelerations. There was a significant increase in the number of decelerations per hour with an associated increase in the mean amplitude but a decrease in the mean duration of decelerations during the first 16 hours of hypoxemia. We conclude that prolonged hypoxemia in fetal sheep leads to an initial increase in the number of both accelerations and decelerations in fetal heart rate followed by a return to normal patterns indistinguishable from those of the normoexemic fetus.

Animals↗
PubMed1989

Patient-flow and waiting times in general medical and dental clinics in Jamaica's primary health care services.

Jamaica has implemented primary health care services closely in accordance with the philosophy of the Declaration of Alma Ata. However, resources are scarce and need to be well managed. Ideal patient-flow in health centres (HCs) would achieve both high efficiency in use of staff time and minimum waiting times for patients. This study of 465 patients in 44 general medical clinics served by 34 doctors and 25 nurse practitioners, and 167 patients served by dentists in each of 15 clinics, showed that mean contact time of patients with doctors was 7 minutes, with nurse practitioners 11 minutes, and dentists 4 minutes. Medical patients waited an average of 3 hours 53 minutes, whilst dental patients waited an average of 2 hours 23 minutes. Doctors', nurse practitioners' and dentists' median times for starting to see patients were 10.00 a.m., 9.35 a.m. and 9.48 a.m. respectively. They were able to work without experiencing any delays in patient-flow since many patients were waiting at the HC by 8 a.m., and preliminary processing was short. It is suggested that if they started seeing patients earlier, patients' waiting times would be shorter. The shortage of pharmacists to dispense drugs after medical consultations added to patients' waiting time. The results were a natural outcome of the low supply of personnel and high demand for services situation being experienced in the medical and dental services.

Ambulatory Care Facilities↗
PubMed1989

Influences of an interviewer's behaviors in child sexual abuse investigations.

The content of an investigatory interview is one of several factors which may influence the data gathered in the course of a sexual abuse investigation. This article focuses on the impact of an interviewer's behaviors upon the information presented by the alleged victim. Behavioral aspects of the interview which may influence the child's information include inappropriate interactional patterns, emotional reactions of the interviewer, and/or changes in continuity of specific behaviors. Recommendations are made to assist investigators in avoiding these interviewing pitfalls and, thereby, minimizing contamination of the child's data.

Child↗
PubMed1988

Probing the active site of flavocytochrome b2 by site-directed mutagenesis.

The three-dimensional structure of flavocytochrome b2 (L-lactate dehydrogenase) from bakers' yeast (Saccharomyces cerevisiae) has recently been solved at 0.24-nm resolution [Mathews & Xia (1987) in Flavins and flavoproteins, Walter de Gruyter, Berlin, pp. 123-131]. We have used this structural information to investigate the roles of particular amino acid residues likely to be involved in the oxidation of L-lactate by kinetic analysis of mutant enzymes generated by site-directed mutagenesis of the isolated gene. The hydroxyl group of Tyr254 was expected to be important for the abstraction of the hydroxyl proton of L-lactate in the oxidation to pyruvate. Replacement of this tyrosine by phenylalanine reduced kcat from 190 +/- 3 s-1 (25 degrees C, pH 7.5) to 4.3 +/- 0.1 s-1. This substitution had, however, no discernable effect on Km for lactate (0.54 +/- 0.03 mM for the mutant compared with 0.49 +/- 0.03 mM for the wild-type enzyme). Arg376 was expected to be essential for productive binding and orientation of L-lactate. Replacing Arg376 with lysine abolished all detectable activity. A total loss of enzymic activity was also observed when Lys349, thought likely to stabilize the anionic form of the flavin hydroquinone, was replaced by arginine. An amino acid residue replacement at a distance from the active site, Ala306 to serine, had a minor but significant effect on kcat (reduced from 190 s-1 to 160 s-1) and Km (increased from 0.49 mM to 0.83 mM) presumably arising from small conformational effects. The implications of these results are discussed in relation to the mechanism of L-lactate oxidation.

Binding Sites↗
PubMed1988

Dermal penetration of avermectin B1a in the rhesus monkey.

Forearms of rhesus monkeys were treated with [3H]avermectin B1a in three different vehicles and concentrations so that the penetration of avermectin B1a through skin could be determined. In order to simulate exposure of farm workers, such as mixer-loaders, applicators, and harvesters, to this pesticide, avermectin B1a was applied to the forearms of the monkeys as an emulsifiable concentrate (300 micrograms/monkey), a diluted emulsifiable concentrate (4.5 micrograms/monkey), and as a suspension in water (216 micrograms/monkey). After 1 or 10 hr of exposure, the treatment area was washed. The levels of radioactivity were determined in the urine, feces, plasma, and wash. On the basis of the amounts of radioactivity excreted in the urine and feces and the levels of radioactivity in the plasma after dermal application compared to those found after intravenous administration of the compound, less than 1% of the doses was absorbed. These data indicate that avermectin B1a would not readily penetrate the skin of farm workers exposed to it. Therefore, the hazard to farm workers exposed to this compound would be substantially mitigated.

Animals↗
PubMed1988

The effects of anions on fluid reabsorption from the proximal convoluted tubule of the rat.

1. Fluid reabsorption from surface proximal tubules of the rat was measured in vivo using stationary microperfusion techniques. Reabsorptive rate (Jv) was measured from droplets containing chloride as the main reabsorbable anion and when chloride was substituted by bromide, iodide, nitrate, acetate, isethionate or methylsulphate in either the tubular lumen alone or in both lumen and peritubular capillaries. 2. In tubules with an intact blood supply, droplet volume decreased in a manner best described by a single exponential and substitution of chloride by nitrate or bromide had no effect on Jv. Substitution by iodide or acetate inhibited Jv by approximately 17% but substitution by methylsulphate or isethionate caused droplets to transiently increase in volume before shrinkage which was itself inhibited by approximately 50%. The inhibitory action of isethionate was found to be concentration dependent. 3. Recollection and analysis of droplets which were initially free of chloride, containing either nitrate or isethionate, showed that chloride entered these droplets, but that the initial rate of chloride entry was greater for nitrate than isethionate droplets. 4. When tubules and capillaries were perfused with chloride solutions containing no bicarbonate, Jv was reduced to about 20% of the value when peritubular capillary blood flow was intact. Substituting chloride in the tubular and capillary perfusion revealed a sequence for supporting fluid reabsorption that was identical to that when chloride was substituted in tubule fluid alone: bromide = nitrate greater than iodide = acetate greater than isethionate. Addition of 2.0 mmol l-1 NaCN reduced the reabsorptive flux to zero. 5. The results of this study are consistent with transcellular transport of anions across the proximal tubular epithelium. The pathways for anion transport are likely to involve a series of non-selective mechanisms such as anion exchangers.

Absorption↗
PubMed1988

Investigatory independence in child sexual abuse evaluations: conceptual considerations.

The procedures used by investigators of sexual abuse allegations have recently come under increasing scrutiny. In this article the importance of investigatory independence is discussed. Conceptual aspects of problematic interviewing techniques that may compromise the investigation of sexual abuse complaints are reviewed. Recommendations are made for the analysis of evaluations relative to the degree of contamination that has been introduced into these assessments.

Child↗
PubMed1987

Inhibition of embryo development by some maternal sera.

Blood sera obtained from patients in an in vitro fertilization and embryo transfer program at the time of oocyte retrieval were tested for their capacities to support embryo development by using them as supplements for media in which mouse embryos were cultured. The sera varied greatly in their capacities to support development of mouse embryos but there was no correlation between the effectiveness of the sera in supporting mouse embryo development and the achievement of pregnancy by the donors of the sera. The capacities of the serum samples to support embryo development also failed to correlate with any of the causes of infertility examined (endometriosis, ureaplasma infection, pelvic adhesive disease, and bilateral tubal occlusion). It was concluded that failure of maternal sera to support embryo development does not necessarily reduce the likelihood that the donors of the sera can become pregnant by in vitro fertilization and embryo transfer procedures.

Animals↗