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Biomedical subjects

J D Browning

Publications and source records attributed to J D Browning.

34 records · Page 2Linked to original sources
PubMed1986

Effect of positional loading of three removable partial denture clasp assemblies on movement of abutment teeth.

Tests demonstrated that the degree of movement of the abutment tooth for a distal-extension base using three different clasp designs was a function of the location of loading. Thus, the null hypothesis, there is no significant difference in the degree of movement of the abutment tooth around the axis of rotation as a function of the position of loading, has been demonstrated to be invalid based on the data obtained in this investigation.

Bite Force↗
PubMed1984

Fabrication of a hollow obturator with fluid resin.

Procedures for fabrication of a hollow obturator with fluid resin have been described. The construction technique is simple and accurate. It allows precise control of the thickness of the resin for minimum weight, but with sufficient thickness to allow adjustment if necessary. The technique can be used for edentulous or partially edentulous patients after maxillary resection.

Denture Design↗
PubMed1983

Effect of zinc deficiency and food restriction on the plasma levels of prostaglandin metabolites in male rats.

The pathological signs of zinc and essential fatty acid deficiencies are highly analogous and aspirin, an inhibitor of prostaglandin synthesis, produces similar pathology when fed at toxic levels. To investigate the possibility that impaired prostaglandin biosynthesis is involved in the etiology of zinc deficiency pathology, the plasma concentrations of three prostaglandin metabolites were determined in zinc-deficient and control rats. Immature male rats were fed a purified diet low in zinc (less than 1 ppm) for 3 weeks. Ad libitum- and pair-fed controls consumed a similar diet supplemented with 100 ppm zinc. The zinc-deficient rats had low plasma zinc and their plasma concentrations of 13,14-dihydro-15-keto PGF2 alpha and 13,14-dihyro-15-keto PGE2 were significantly higher than those of the pair-fed controls. Plasma 6-keto-PGF1 alpha was not different between the zinc-deficient and pair-fed groups, but was significantly lower in deficient rats than in ad libitum-fed controls. The pair-fed controls had significantly lower plasma concentrations of all three metabolites than did the ad libitum-fed control group. The results suggest no impairment of prostaglandin production in zinc-deficient male rats.

6-Ketoprostaglandin F1 alpha↗
PubMed1983

Plasma levels of prostaglandin metabolites in zinc-deficient female rats near term.

To investigate the possibility that impaired prostaglandin biosynthesis is involved in the development of postpartum illness in zinc-deficient female rats, plasma levels of three prostaglandin metabolites, 13,14-dihydro-15-keto PGF2 alpha, 13,14-dihydro-15-keto PGE2, and 6-keto PGF1 alpha were determined on day 22 of gestation. During the gestation period female rats were fed low zinc (less than 1 ppm) diets based on soybean protein or similar control diets (100 ppm Zn). Two levels of vitamin E, 15 and 65 IU per kilogram, were added to the diet. Zinc deficiency in dams fed the diet containing 65 IU/kg vitamin E resulted in significantly higher plasma levels of 13,14-dihydro-15-keto PGF2 alpha than controls; plasma 6-keto PGF1 alpha levels were not different. Zinc-deficient dams fed the basal diet containing 15 IU/kg vitamin E had significantly higher plasma levels of all three prostaglandin metabolites than controls. The pathology of zinc deficiency is not due to decreased prostaglandin production, but the present results and the pathological signs are consistent with failure of prostaglandin function.

6-Ketoprostaglandin F1 alpha↗
PubMed1983

Platelet arachidonate metabolism and platelet function in zinc-deficient rats.

To determine the effect of zinc status on arachidonate metabolism and the initiation of aggregation by a prostaglandin endoperoxide analog (U-44069), immature rats were fed for 5 days a low zinc (less than 1 ppm) or control (100 ppm Zn) diet based on soybean protein. In vitro production of thromboxane B2 (TXB2) by platelet-rich plasma after stimulation by either arachidonate (0.2 mM) or ADP (0.2 microM) was not changed by dietary zinc deprivation, even though bleeding time was prolonged. Oxygenation of exogenous arachidonate, catalyzed by either the cyclooxygenase or lipoxygenase pathway, was not affected by zinc deficiency. Platelet aggregation in response to the prostaglandin endoperoxide analog at both 8 and 16 microM was impaired by dietary zinc deprivation. While short-term zinc deprivation decreased platelet response to minimal levels of aggregating agents, production of arachidonate metabolites was unimpaired. It is postulated that platelet response to the products of arachidonate metabolism is reduced.

Adenosine Diphosphate↗
PubMed1982

Acute myelogenous leukaemia following cytotoxic therapy: five cases and a review.

Acute myelogenous leukaemia (AML) following cytotoxic chemotherapy has been reported increasingly. Five new cases are presented including the first described following treatment for immune thrombocytopaenia. A review of the literature has revealed 226 case reports of treatment-linked AML with sufficient detail to permit further study. Of the total of 231 patients, 76 (33 per cent) followed Hodgkin's disease, 59 (25.5 per cent) multiple myeloma, 22 (9.5 per cent) non-Hodgkin's lymphoma, 32 (14 per cent) other solid tumours and 42 (18 per cent) non-malignant diseases. The time interval from the start of chemotherapy to the diagnosis of AML was similar in all disease groups whether the patients had received radiotherapy or not. Differences emerged when the duration of exposure to chemotherapy was analysed in the individual disease groups; exposure was shorter in those patients treated for Hodgkin's disease and solid tumours than with the others suggesting that the pattern of administration of chemotherapy may be important. The effects of radiotherapy in addition to chemotherapy could not be defined precisely, but the study highlights the particular risk that appears to arise from alkylating agents, and the need to define optimal methods of administration of chemotherapy with minimal risk of inducing leukaemia.

Adolescent↗
PubMed1981

Prevention of contrast-induced bradycardia during coronary angiography.

A double-blind study of 90 patients undergoing coronary angiography was performed to determine the safety and efficacy of 0.6 mg atropine sulfate in preventing contrast-induced bradycardia. Coronary angiography performed using the Sones technique resulted in ventricular pauses of greater than 2 seconds in 3 of 49 patients (6%) who received prophylactic atropine and 20 of 41 patients (49%) receiving placebo. Though the pauses were usually due to atrial asystole, 26% of those with greater than 2 second pauses did so because of transient complete heart block. Prophylactic atropine did increase resting heart rate but did not cause other arrhythmias or increase the frequency of angina pectoris despite the presence of severe coronary disease. Our data indicate that contrast-induced asystole is very common, cannot be predicted by consideration of "precatheterization data," and can be prevented effectively and safely by use of prophylactic atropine sulfate.

Angiography↗
PubMed1980

Fine screen filtration of banked blood: effect on red cell survival.

Two fine screen mesh microfilters and the Baxter blood administration set commonly used in U.K. hospitals were compared for their effect on the red cell survival of transfused stored autologous blood in six healthy males. The effect of the filtered transfusions on pulmonary gas exchange and on blood coagulation was measured. No significant difference was found between either microfileter and the Baxter giving-set for the red cell survival of transfused blood. Pulmonary gas exchange and coagulation were unaffected by transfusion of one unit of whole blood. Post-transfusion bilirubin concentrations were significantly less with one of the microfilters compared with the Baxter giving-set, possibly because of trapping of effete red cells within the filter. An unsuspected finding was the effect of transfusion in increasing the peripheral blood neutrophil count.

Adult↗
PubMed1980

Adult pulmonary cytomegalic inclusion disease: report of a case.

A case is presented of pulmonary cytomegalic inclusion disease in adult. The condition was only diagnosed post mortem. A detailed description of the inclusions and inclusion-bearing cells is given. Histochemical observations which reveal an outer and inner zone to the intranuclear inclusion body are confirmed. Electron microscopy shows the viral basis of the infection. The morphology of the virus particles is compatible with a herpesvirus infection.

Cytomegalovirus↗
PubMed1979

Cold lymphocytotoxins in connective tissue disorders.

Sixty-eight patients with various connective tissue disorders, 5 relatives of patients and 26 members of staff from the Centre for Rheumatic Diseases were studied for the presence in their sera of cold lymphocytotoxic antibodies. Antibodies were found in 71 percent of patients with systemic lupus erythematosus, 27 per cent of patients with rheumatoid arthritis, 0 per cent of the small group of relatives and 3.8 per cent of the controls. Absorption studies did not show T or B specificity of the antibodies. The control group, working in close proximity to the patients or their sera did not show any increased incidence of antibodies as compared to control groups of other studies. Red blood cell anti I or HI was found in the sera of 28 per cent of those with cold lymphocytotoxic antibodies. No correlation was found between the presence of the antibodies and number of blood transfusions or pregnancies, increasing age, R3 titre or antinuclear factor.

Adult↗
PubMed1975

Formation of auto-rosettes by peripheral blood lymphocytes.

A mean of 3-4% (0-5-19-5%) of the peripheral blood lymphocytes of normal adults were shown to bind three or more autologous erythrocytes in vitro to form auto-rosettes. Marked individual fluctuations were observed. Increased percentages were observed in patients with cancer, but not in other selected groups, including a group who had undergone thymectomy for myasthenia gravis. Auto-rosette formation was shown to be a property of T cells by the demonstration of (a) simultaneous binding of autologous and sheep erythrocytes, (b) non-inhibition of auto-rosette formation by anti-immunoglobulin, and (c) formation of auto-rosettes by mitogen-stimulated T blasts. Auto rosette formation is a property of high percentages of human thymocytes, and of lymphocytes treated with neuraminidase or stimulated to blast-cell trans-formation by phytomitogens. It is suggested that auto-rosette formation by these cells is related to their relatively low content of cell-coat sialic acid, as compared with untreated T lymphocytes. The possible influence of the cell coat on lymphocyte function is discussed briefly.

Animals↗