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Biomedical subjects

A Walker

Publications and source records attributed to A Walker.

At least 235 records · Page 13Linked to original sources
PubMed1989

Hypothalamic obesity: comparison of radio-frequency and electrolytic lesions in weanling rats.

Female rats were subjected to radio-frequency or anodal electrolytic lesions of the ventromedial hypothalamus (VMH) when 28 days old. Blood samples for determination of basal plasma insulin and glucose levels were taken on postoperative day 30 (Experiment 1) and on day 10 (Experiment 2). Body weight and daily food intake of rats with either type of lesion did not differ from unoperated animals during the first 10 days, but rats with electrolytic lesions, unlike radio-frequency lesioned animals, displayed excess food intake and weight gain starting in the third postoperative week. Both types of lesions produced stunted linear growth and a higher than normal Lee Obesity Index. Only the rats with electrolytic VMH lesions were significantly hyperinsulinemic on postoperative day 30, with a mean plasma insulin level that was at least double that observed in unoperated or radio-frequency lesioned animals. On day 10, however, the animals with electrolytic lesions had markedly lower plasma insulin and glucose levels compared to the other two groups, which did not differ from one another. There was no apparent difference in the size of the lesions produced by the two techniques, and it is therefore concluded that some of the endocrine dysfunctions resulting from electrolytic VMH lesions are due to metallic ion deposits (stimulating adjacent tissue) rather than to tissue ablation.

Animals↗
PubMed1989

Screening and the costs of treating colorectal cancer: some preliminary results.

This paper describes a hospital costing analysis of 85 colorectal cancer patients treated in the context of a randomised control trial at the Queen's Medical Centre, Nottingham. Estimates are presented for investigation, surgical and inpatients costs. Comparisons between study and control group patients reveal only a small difference in overall costs of treatment.

Aged↗
PubMed1989

Theileria annulata sporozoite surface antigen expressed in Escherichia coli elicits neutralizing antibody.

Theileria annulata is an economically important protozoan parasite that threatens an estimated 250 million cattle with the disease tropical theileriosis. Development of a defined subunit vaccine is one means of trying to develop control measures against the disease. To this end we have characterized a surface antigen complex of the infective stage (sporozoite), by using a monoclonal antibody that neutralizes sporozoite infectivity in vitro. We have cloned the gene coding for this complex and have demonstrated that a fusion protein expressed from a fragment of this gene elicits strong neutralizing antibodies. Furthermore we provide data on the structure and expression of this gene. In particular we show that the region of the gene, expressed in one clone, codes for a protein segment relatively rich in proline residues. Also we demonstrate that expression of this gene appears to be stage specific, transcripts being present only in the sporoblast and sporozoite stages. The relevance of these findings to the production of a defined subunit vaccine is discussed.

Amino Acid Sequence↗
PubMed1989

The long-term effect of a positive pressure respirator on the specific antibody response in pigeon breeders.

A group of pigeon fanciers with Pigeon Breeder's Lung wore a positive pressure respirator with a full mask and hood when working with pigeons. Serial measurements of specific IgG antibody to pigeon globulin (ELISA) were made in 22 subjects. Thirteen wore a respirator (monitored over 14 months) and nine did not (monitored over 3 months). Following introduction of the respirator, the serum antibody to pigeon globulin significantly decreased when compared with the non-respirator group. This fall in antibody persisted over 14 months reflecting the reduction of antigen inhalation. Although circulating antibody decreased in all those wearing respirators, the remaining levels were still within the range that can be associated with clinical symptoms possibly because of inward leakage of antigen bypassing the filter.

Adult↗
PubMed1989

Inferences from quantitative analysis of dental microwear.

Tooth microwear studies have been carried out for several reasons in the last decade. Most effort has been put into categorizing wear types that reflect dietary preferences in order to reconstruct the diet of extinct species. Several studies have shown that, for primates, carnivores and ruminants, it is possible to differentiate statistically the microwear associated with the major dietary adaptations in the group. It has further been found that more subtle dietary changes, such as seasonal ones, can be picked up if the sampling is good enough. It is important to recognize that, although it may be a valuable and legitimate concern to study the specific causes of different microwear patterns, that information is not essential for dietary reconstruction, if different microwear states can be shown empirically to correspond to different dietary regimes. Image enhancement and optical diffraction methods offer hope of automated scanning of large samples. This will be a major benefit as the methods currently in use are labor-intensive and time-consuming. Finally, it is urged that as many methods as possible be used to solve problems of dietary reconstruction.

Animals↗
PubMed1989

Preliminary observations on clotting under three hydrocolloid dressings.

Four patients with five wounds were randomly assigned to treatment with three occlusive dressings: DuoDERM, Restore and Comfeel Ulcus; the dressings were left intact for 24-48 h. When the dressings were removed, it was found that wounds that had been covered with Restore and Comfeel contained coagulated sanguinous material. Two wounds that had been covered with Comfeel and Restore, respectively, were then covered with DuoDERM, while one wound previously covered with DuoDERM was covered with Restore. Either no clotting occurred under DuoDERM or clots may have resolved. Although these preliminary data suggest that DuoDERM gel may have fibrinolytic properties, more extensive and controlled studies are needed to assess the characteristics of this dressing.

Bandages, Hydrocolloid↗
PubMed1988

Heparan sulphate-degrading endoglycosidase in liver plasma membranes.

An endoglycosidase is described in isolated liver plasma membranes that brings about a rapid and selective degradation of membrane-associated heparan sulphate, pre-labelled biosynthetically with Na2(35)SO4. The enzyme attacked mainly the polysaccharide chains of a hydrophobic membrane proteoglycan and it had little effect on a proteoglycan that could be displaced from the membranes with 1.0 M-NaCl. The highest activity was measured in the pH range 7.5-8.0, and the enzyme was almost completely inhibited below pH 5.5. Breakdown of susceptible polysaccharide chains was fast, being complete in 20-30 min. The major oligosaccharide fraction (Mr approx. 6000) produced by the enzyme was considerably smaller than the intact heparan sulphate chains. Enzyme activity was retained in membranes solubilized in 1% (v/v) Triton X-100. The high pH optimum and plasma-membrane association distinguish this enzyme from other heparan sulphate-degrading endoglycosidases that have acid pH optima and may be of lysosomal origin. A plasma-membrane endoglycosidase could modulate cellular interactions mediated by heparan sulphate, and/or release biologically active fragments of the polysaccharide from the cell periphery.

Animals↗
PubMed1988

In vitro fertilisation in a small unit in the NHS.

In vitro fertilisation is one of the most effective new treatments for infertility, but financial restrictions have made it impossible for it to be widely carried out in the National Health Service. We report on the establishment of a small, largely self funded, unit that was set up with the help of the local health service management. All cycles are programmed so that most work is carried out during the working week; oocyte recoveries are performed as outpatient procedures without general anaesthesia and guided by ultrasound. Roughly a tenth of treatment cycles and roughly a fifth of embryo transfers resulted in a clinical pregnancy.

England↗
PubMed1988

Prenatal testing for Duchenne and Becker muscular dystrophy.

DNA studies were undertaken following 53 requests from pregnant women at risk for Duchenne and Becker muscular dystrophy, including 32 in whom there was only 1 affected individual in the family (sporadic cases). The DNA restriction fragment length polymorphisms were informative in 51 of the 53 cases. In 10 of 25 pregnancies with male fetuses the risk to the fetus was reduced to 5% or less. Referral of possible carriers before onset of pregnancy is strongly advisable on both medical and economic grounds. The banking of DNA from affected individuals for future use in the estimation of risks to their relatives should be encouraged.

Carrier State↗
PubMed1988

New Australopithecus boisei specimens from east and west Lake Turkana, Kenya.

New specimens of Plio-Pleistocene Australopithecus boisei are described from east and west Lake Turkana in Northern Kenya. These include a cranium and partial mandible from deposits close to 2.5 Myr and two partial crania and two mandibles from later horizons. The earlier fossils enable us to decipher, for the first time, some of the in situ evolution of this species within the Turkana Basin. The following are among the important changes in the cranium through time: 1) increase in size and change in shape of the braincase, 2) changes in the meningeal vessel pattern and possibly in the venous drainage pattern, 3) increased flexion of the cranial base and decreased prognathism, and 4) changes in the temporal bone to bring about a more vertical posterior face of the petrous pyramid and the development of a strong articular eminence.

Animals↗
PubMed1988

Stimulation of growth of Nb2 lymphoma cells by interleukin-2 in serum-free and serum-containing media.

The human recombinant alanine-125 analogue of interleukin-2 (IL-2) causes a dose-dependent mitogenic response in rat lymphoma Nb2-11C cloned cells when tested in serum-containing medium and serum-free medium. IL-2 and hGH elicit their growth stimulation through different receptors since IL-2 does not compete with 125I-hGH for binding to Nb2 cells and Met14hGH, an antagonist of hGH, inhibits the hGH-stimulated growth of Nb2 cells but not that caused by IL-2. The tumor promoter, 12-O-tetradecanoyl phorbol-13-acetate (TPA) potentiates the action of hGH on Nb2 cells grown in both serum-containing and in serum-free medium. TPA to a variable degree also potentiates IL-2-stimulated growth of Nb2 cells when cultured in medium containing serum but has no effect on cells grown in serum-free medium. In conclusion, IL-2 is a potent mitogen for Nb2-11C cells.

Animals↗