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Biomedical subjects

A Wood

Publications and source records attributed to A Wood.

At least 109 records · Page 6Linked to original sources
PubMed1990

Cardiac surgery in Down syndrome.

Between January 1976 and December 1987 42 children with Down syndrome and congenital heart disease underwent cardiac surgery. Four children had two operations. Age at the time of surgery ranged from 11 days to 14 years. The commonest operative procedure was repair of a patent ductus arteriosus. Four patients died post-operatively, two following repair of a complete atrio-ventricular canal defect (CAVD), one following correction of tetralogy of Fallot in association with a CAVD, and a fourth following closure of ventricular septal defect and atrial septal defect. The mortality for those who had open heart surgery was 13.3% and for the series as a whole the mortality was 6.6% over a period of follow-up ranging from two months to four years. A relatively conservative approach has been adopted with regard to surgery, based on the shorter natural expectation of life in Down syndrome, the complexity of many of the cardiac lesions involved and the recognition of the frequency of early intellectual deterioration in Down patients.

Adolescent↗
PubMed1989

Hepatitis B vaccination and GPs.

Doctors seem ambivalent to their own health needs even though, when it comes to infectious diseases, their families are also at risk. This study looks at GPs' attitudes to getting themselves vaccinated against hepatitis B. Despite the risk, 21 per cent of GPs have no intention of being vaccinated.

Attitude of Health Personnel↗
PubMed1989

Estradiol binding to plasma proteins after changing to a low-fat diet.

Breast cancer development is believed to be associated with both dietary fat consumption and the proportion of biologically available estradiol in the serum. A study was undertaken to determine if a reduction in fat consumption would influence the binding, and thus the bioavailability, of estradiol. Groups of pre- and postmenopausal women were randomized to begin either a standard western diet (40% energy from fat) or a low-fat diet (20% energy from fat). After two months, each woman changed over to the alternate diet. Blood samples were taken at the end of each dietary period. Change of diet made no significant difference to the proportions of nonprotein-bound (free), albumin-bound, or sex hormone binding globulin-bound estradiol in this study. However, the number of women studied and the duration of change were relatively small.

Adult↗
PubMed1989

Airway mucosal bioelectric potential difference in cystic fibrosis after lung transplantation.

Bioelectrical potential difference (PD) across the respiratory mucosa is raised in cystic fibrosis (CF). We have recorded airway potentials from seven patients with CF who had undergone heart-lung transplantation and from eight patients without CF who had had transplants for cardiovascular disease; comparison of these populations controls for the effects of denervation and immunosuppressive treatment. Six patients without CF who had not had transplants formed an additional control. PD was recorded during routine fiberoptic bronchoscopy, using a Ringer's-perfused exploring bridge connected across a high impedance amplifier to an intravenous reference bridge. Bronchial lavage and sputum culture revealed no evidence of infection. Bronchial PD was similar in all three groups of patients at equivalent sites. However, nasal PD was raised in the CF group (mean value, 44 mV +/- 3.9 SE) compared with the patients who had transplants for cardiovascular disease (mean, 18 mV +/- 1.1 SE), and the control patients (mean, 15 mV +/- 1.2 SE). We conclude that the epithelial defects that result in raised airway potentials in CF do not recur in the transplanted lung.

Adolescent↗
PubMed1989

Depressed activities of purine enzymes in lymphocytes of patients infected with human immunodeficiency virus.

Enzyme activities were studied in peripheral blood lymphocytes from patients infected with, or at risk for, infection with human immunodeficiency virus (HIV). No significant differences were observed in the HIV-infected and HIV-seronegative high-risk patients with regard to enzyme activities of hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8) and purine nucleoside phosphorylase (EC 2.4.2.1) in peripheral blood. Adenosine deaminase (EC 3.5.4.4) was significantly (P less than 0.02) depressed in asymptomatic HIV-seropositive patients and HIV-seronegative patients at high risk of HIV infection as compared with a healthy HIV-seronegative population. Adenosine kinase (AK, EC 2.7.1.20) was significantly increased in the asymptomatic seropositive (P less than 0.02) and also in the HIV-seronegative high-risk groups (P = 0.01) compared with the normal controls. AK activity was significantly lower in subjects with AIDS than in the asymptomatic (P less than 0.002) and high-risk groups (P less than 0.01). Taken together, these results indicate that adenosine deaminase and AK activities are influenced by the health of the patient, and that measurement of AK activity may prove useful in monitoring the clinical progress of patients with HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Accurate measurement of airway thermal challenge.

Rapid and accurate measurement of air temperature is needed to determine both heat and water losses from the respiratory tract during breathing. We have designed, constructed and validated a low dead-space, two-channel valve/mouthpiece which prevents mixing of inspired and expired air outside the body. The effects of airflow on the thermocouple response time and of thermocouple position within the airstream on the temperature measured were assessed. The 63% thermocouple response time fell from 159 to 78.8 ms as airflow rose from 23.7 to 297 1 min-1, a range including the peak flows observed while breathing at rest and during exercise. Measurement of temperature profiles across the valve/mouthpiece at different flows indicated that thermocouples were best positioned at the centre of the airstream, though small deviations did not adversely affect accuracy.

Body Temperature Regulation↗
PubMed1988

Contact guidance on microfabricated substrata: the response of teleost fin mesenchyme cells to repeating topographical patterns.

The mesenchymal tissue component of the teleost pectoral fin bud has been explanted onto microfabricated quartz discs containing patterns of regular grooves of dimensions similar to those encountered by contact-guided cells in the intact fin system. Computer-aided analysis of cell migration on five separate patterns, from 1.8 to 7.4 microns repeat spacing, revealed that migration was predominantly aligned parallel to the long axis of the grooves, with individual cells becoming highly polarized, and the highest index of alignment (3.7) produced on the widest repeat spacings. When these cells are cultured on planar quartz, which is both chemically and physically isotropic, they flatten and adopt a morphology similar to that shown by cultured fibroblastic cell types on flat surfaces, suggesting that fin mesenchymal cells are not intrinsically predisposed to adopt an arborized morphology, like that observed in the intact fin bud. These results clearly demonstrate a directional migration in response to substratum topography, from a cell type known to be contact guided in vivo, and in the complete absence of adhesive heterogeneities.

Animals↗
PubMed1988

Antitussive properties of inhaled bronchodilators on induced cough.

We have studied the antitussive effects of two anticholinergic agents, oxitropium bromide (200 micrograms) and ipratropium bromide (80 micrograms), and a combined beta-agonist and anticholinergic preparation containing fenoterol hydrobromide (200 micrograms) and ipratropium bromide (80 micrograms), in 16 normal and ten asthmatic volunteers in a double-blind, randomized, placebo-controlled crossover trial. Cough was induced by inhalation of ultrasonically nebulized distilled water and hypotonic saline solution. All treatments significantly reduced the cough response to inhaled distilled water aerosol when compared with placebo (p less than 0.001). There was no difference between oxitropium bromide and ipratropium bromide (p greater than 0.05), but the combination preparation displayed a greater antitussive effect than either oxitropium bromide (p less than 0.05) or ipratropium bromide (p less than 0.025). Cough frequencies in response to hypotonic 0.18 and 0.32 percent saline aerosol were lower than those obtained with distilled water (p less than 0.005) for all treatments. Asthmatic patients coughed less frequently than normal volunteers in response to all solutions when placebo was given (p less than 0.05), but there is no evidence to suggest that the response to treatment was different in the two groups. Our results suggest that inhaled anticholinergic bronchodilators alone or in combination with beta 2-adrenergic agonists might be effective in the treatment of pathologic cough.

Administration, Inhalation↗
PubMed1988

Modification by pertussis toxin of the responses of bovine anterior pituitary cells to acetylcholine and dopamine: effects on hormone secretion and 86Rb efflux.

Acetylcholine is known to stimulate the secretion of growth hormone and prolactin and the efflux of 86Rb from bovine anterior pituitary cells: dopamine prevents the stimulation of 86Rb efflux and of prolactin but not growth hormone secretion. The sensitivity of these responses to pertussis toxin has been determined. Treatment of bovine anterior pituitary cells in primary culture with pertussis toxin (18 h, 100 ng/ml) did not modify the stimulation of prolactin secretion by acetylcholine, but prevented its inhibition by dopamine. In lactotrophs, dopamine but not acetylcholine receptors are therefore coupled to secretion through a pertussis toxin substrate. The stimulation of 86Rb efflux by acetylcholine was also unaffected by pertussis toxin and, again, its inhibition by dopamine was prevented. Treatment of the cells with pertussis toxin enhanced the secretion of growth hormone in response to acetylcholine. Nitrendepine (1 mumol/l) prevented the cholinergic stimulation of growth hormone but not prolactin secretion from these cells. Acetylcholine increased the cytoplasmic calcium concentration and this rise was enhanced by treatment of the cells with pertussis toxin. Nitrendepine partially inhibited the rise in calcium caused by acetylcholine, and prevented the enhancement of the rise following pertussis toxin treatment. Cholinergic stimulation of growth hormone therefore depends on calcium entry through nitrendepine-sensitive channels, whereas stimulation of prolactin secretion does not, and in somatotrophs a pertussis toxin substrate may limit calcium entry through these channels. These different sensitivities of somatotrophs and lactotrophs to pertussis toxin and nitrendepine may reflect differences in the properties of the predominant calcium currents in the two cell types.

Acetylcholine↗
PubMed1988

Cyclosporin A and anti-glomerular basement membrane antibody glomerulonephritis in rats.

In a telescoped model of antiglomerular basement membrane (GBM) antibody induced nephritis, Lewis strain rats were injected in the footpad with rabbit IgG on day 0 and then given a single intravenous injection of rabbit anti-rat GBM antibody on day 5. Proteinuria developed within 24 h and renal histology 7 days later showed a focal or diffuse proliferative glomerulonephritis. In this study rats treated as above were given Cyclosporin A (CyA) 20 mg/kg daily by intraperitoneal injection from day 0 or from day 5. Rats given CyA plus anti-GBM antibody developed extensive glomerular infiltration with polymorphs and glomerular thrombosis, lesions not seen with unmodified anti-GBM nephritis or in rats who received CyA alone. The mechanism by which CyA given prior to or at the onset of immunological insult in this model worsens glomerular injury is unclear.

Animals↗
PubMed1987

Comparison of the stimulation of glycosaminoglycan synthesis in cultures of mononuclear cells from blood and of fibroblastic cells.

A small molecular weight factor, derived from bovine bone ('matrigenin'), stimulated glycosaminoglycan and proteoglycan synthesis of cultured human fibroblastic cells but not of mononuclear cells from human blood. However, proteoglycan synthesis and secretion by the mononuclear cells was stimulated by the addition of concanavalin A. The proteoglycan from the concanavalin-A-stimulated mononuclear cells was of smaller molecular weight than the proteoglycan from the 'matrigenin'-stimulated fibroblastic cells. The major increase in proteoglycan synthesis and secretion occurred much later during the culture period for concanavalin-A-stimulated mononuclear cells than for 'matrigenin'-stimulated fibroblastic cells.

Cells, Cultured↗
PubMed1987

Analysis of in vivo cell movement using transparent tissue systems.

The embryos of certain teleost species are transparent and cell behaviour within the intact embryo can be observed and recorded using Nomarski microscopy coupled with time-lapse video recording or time-lapse cine filming. In this report we review some of our recent analyses of cell behaviour patterns underlying key morphogenetic events. (1) Contact-guided cell migration through a structurally ordered extracellular matrix during fin development; (2) movement of tissue layers during epibolic overgrowth; and (3) cell 'social' behaviour during the establishment of the body axis (i.e. notochord formation and somitogenesis). These results, on cell behaviour correlated with normal morphogenesis, provide a baseline for further work in which hypotheses concerning subcellular and molecular controls of cell behaviour can be tested by experimental perturbation in vivo.

Animals↗
PubMed1987

Antisera to the variable region of ras oncogene proteins, and specific detection of H-ras expression in an experimental model of chemical carcinogenesis.

Antisera were prepared in mice, rats and rabbits by immunization with peptides corresponding to regions of highest variability, located near the C-termini of four ras proteins. Two of these, H-ras (171-189) and K-rasB (171-186), react uniquely with H-ras and K-rasB gene products in immunoblots and immunoprecipitation reactions. Affinity-purified rabbit H-ras (171-189) antibody detects H-ras p21 in tissue culture cells and in tissue sections. Epithelial cells in normal mouse skin and cells in papillomas and carcinomas, in a mouse model system of chemical carcinogenesis in which mutational activation of H-ras occurs with high frequency, express high levels of H-ras p21 protein. These results suggest an hypothesis to explain the mechanism and preferential activation of particular ras loci in certain neoplasia.

Amino Acid Sequence↗
PubMed1986

Microbial flora of the eyes of cattle.

The bacteria and mycoplasma occurring in the eyes of normal healthy calves were monitored in three groups of animals from purchase at about one week old to slaughter at about 15 months old. Non-haemolytic Moraxella bovis, Branhamella catarrhalis and Mycoplasma bovoculi were all isolated regularly, though their seasonal occurrence varied. The significance of these findings with respect to infectious bovine keratoconjunctivitis is discussed.

Animals↗
PubMed1986

Immunochemical recognition of phosphate ester derivatives of phenol rings is dependent upon the electronic charge of the ester group.

The recognition of phosphate and sulphate esters of tyrosine residues has been studied employing antisera with specificity for tyrosine phosphate, and the enzymes aryl sulphatase, and acid and alkaline phosphatases. The ability of tyrosine phosphate, and of phosphate esters of phenol, to inhibit the antiserum was pH dependent. The capacity to effect inhibition appeared to correlate with alterations in the ionisation of the inhibitor. Moreover, the antisera with reactivity for tyrosine phosphate had no reactivity with tyrosine sulphate or sulphate esters of phenol at any pH value studied. The enzymes alkaline phosphatase, acid phosphatase, and aryl sulphatase were also studied. The phosphatases were found not to hydrolyse sulphate ester containing substrate analogues at any pH value in the range 5.0-9.0. In contrast, aryl sulphatase appeared to hydrolyse phosphate esters at pH 5.0 and 7.0, but not at pH 9.0.

Acid Phosphatase↗
PubMed1985

Plasma bile salt levels in patients presenting with generalised pruritus: an improved indicator of occult liver disease.

Fasting plasma bile salt concentrations were measured in 26 patients presenting to a Skin Department who had generalised pruritus without primary skin disease, as part of a screening investigation for systemic causes of pruritus. The results were compared with conventional tests of hepatic function. Plasma-conjugated cholate measurements identified all patients with hepatobiliary disease. Conventional liver function tests were abnormal in these patients but also in five patients with no other evidence of hepatic dysfunction. Fasting conjugated-cholate measurements offer a useful screening test for identifying hepatobiliary disease in patients presenting with generalised pruritus.

Adult↗