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Biomedical subjects

J Edwards

Publications and source records attributed to J Edwards.

At least 271 records · Page 15Linked to original sources
PubMed1987

Mutations that increase the mitotic stability of minichromosomes in yeast: characterization of RAR1.

In an attempt to identify proteins involved in the initiation of DNA replication, we have isolated a series of Saccharomyces cerevisiae mutants in which the function of putative replication origins is affected. The phenotype of these Rar- (regulation of autonomous replication) mutants is to increase the mitotic stability of plasmids whose replication is dependent on weak ARS elements. These mutations are generally recessive and complementation analysis shows that mutations in several genes may improve the ability of weak ARS elements to function. One mutation (rar1-1) also confers temperature-sensitive growth, and thus an essential gene is affected. We have determined the DNA sequence of the RAR1 gene, which reveals an open reading frame for a 48.5 kDa protein. The RAR1 gene is linked to rna1 on chromosome XIII.

Amino Acid Sequence↗
PubMed1987

The family relations of female juvenile delinquents.

This study evaluated the assumption that the family relations of female delinquents are more dysfunctional than those of male delinquents. In a 2 X 2 (gender by delinquency status) design, 32 intact families were matched on demographic variables, and the male and female delinquents were matched on arrest data. Mothers, fathers, and adolescents were administered a self-report personality inventory and were observed during a family interaction task. Consistent with the extant literature, families of delinquents had low rates of facilitative information exchange and delinquent adolescents were more dominant toward their mothers than were well-adjusted adolescents. It was also observed that fathers of delinquents were more dominant toward their wives than were fathers of well-adjusted adolescents. In regard to the primary purpose of the study, it was observed that mother-adolescent dyads and parents in families of female delinquents had higher rates of conflict than their counterparts in families of male delinquents. In addition, the fathers of female delinquents were more neurotic than the fathers of male delinquents. These findings provide some support for the view that the families of female delinquents are especially dysfunctional.

Adolescent↗
PubMed1987

Estimation of endothelial receptor sites with the mean transit time approach.

A new procedure for quantitating endothelial receptor sites is described. The mean transit time of the passage of an appropriate radio-labeled ligand from the artery to vein of an organ is compared to the mean transit times of a vascular indicator and a water label. The concentration of the unlabeled ligand is progressively increased to define that concentration at which half of the enzyme sites are occupied. Values are calculated for the number of receptor sites accessible during a single circulation in each ml of exchangeable tissue water. This approach is illustrated by estimating the sites of carbonic anhydrase present on the pulmonary endothelium, utilizing labeled acetazolamide as a ligand. Preliminary studies of the receptor sites on isolated endothelial cells suspended in an elutriator are also presented.

Acetazolamide↗
PubMed1987

Gordon's syndrome in pregnancy.

A case of Gordon's syndrome (short stature, defective dentition, hyperkalemic, hyperchloremic acidosis, and chronic hypertension) complicating pregnancy is presented. Rigid salt restriction with diuretic therapy not only controlled the hypertension but also reversed the metabolic abnormalities. This is the first case report of a pregnancy complicated by this rare syndrome.

Acidosis, Renal Tubular↗
PubMed1987

Occupational asthma and rhinitis related to laboratory rats: serum IgG and IgE antibodies to the rat urinary allergen.

Allergic reactions to rat urinary proteins are an important cause of occupational asthma and rhinitis among laboratory workers. We have measured IgG and IgE antibodies to a purified rat urinary allergen in sera from 179 laboratory workers of whom 30 reported symptoms on exposure to rats. There was a very good correlation between IgE antibodies and positive skin tests. In addition, there was a close correlation between reported asthmatic reactions and serum IgE antibody to rat allergen: IgE ab was present in 12/18 of workers with asthmatic reactions but in only 2/135 of workers without symptoms (p less than 0.001). Serum IgG antibodies to rat allergen were present in all sera with IgE antibody but were also present in 30% of asymptomatic individuals. The incidence and quantity of IgG antibody correlated with the degree of exposure to animals (i.e., hours per day) but not with the length of exposure in years. Our results on rat allergy confirm that there is an increased incidence of asthma among individuals who were atopic as judged by positive skin tests to other allergens. However, this relationship did not apply to individuals with rhinitis alone, and excluding atopic individuals from employment would have been a very inefficient method of reducing asthma or rhinitis in this group. Our results confirm that IgE antibody responses to rat urinary allergen are an important cause of occupational disease. The results for IgG antibody suggest that their prevalence represents a marker for the degree of exposure to rat proteins.

Animals↗
PubMed1987

The influence of age on the cardiovascular toxicity of intravenous bupivacaine in young dogs.

A study in anaesthetised dogs aged 2, 6, 13, 26 and 52 weeks or older was done to determine the dose of IV bupivacaine given by infusion required to produce severe cardiovascular depression as measured by a drop in mean blood pressure to about 25 mmHg or the development of life-threatening dysrrhythmias. Plasma local anaesthetic concentration was analysed at the time of ceasing the infusion. The toxic dose was significantly less in the six-week-old group than younger or older animals. The plasma concentrations associated with toxicity in the groups 13 weeks and younger were significantly lower than in the older dogs. Treatment of the induced toxicity included hyperventilation, adrenaline infusion, bretylium and/or cardioversion. The response to treatment was better in young dogs than adult dogs.

Age Factors↗
PubMed1986

The effects of various levels of intraocular pressure on the rabbit's outflow system.

The effects of various levels of intraocular pressure on the morphology of the rabbit outflow system were investigated. In a total of 20 rabbits, intraocular pressure was maintained at various levels between 0-50 mmHg in the experimental eye and at 20 mmHg in the control eye for 1 hr. Flow rates into the eyes were measured by following the movement of a miniscus through a calibrated capillary tube. Progressive increase in pressure lead to distension and enlargement of the ciliary cleft. The meshwork tissues stretched and distended, and the vessels of the angular aqueous plexus had pressure-sensitive giant vacuoles of their endothelium. These vessels were prone to closure at pressures of 30 mmHg and greater. Difficulties associated with quantitation of giant vacuoles in this species were discussed.

Animals↗
PubMed1986

Sindbis virus-mediated cell fusion from without is a two-step event.

The process by which Sindbis virus induces the fusion of BHK-21 cells in monolayer cultures after exposure to low pH was examined. The fusion process was found to require an exposure to low pH followed by a return to conditions closer to neutral pH. The rate at which cells fused was affected by the pH to which the monolayers were exposed, subsequent to the initial exposure to acid conditions. Virus-mediated cell fusion was not observed if the virus-cell complexes were maintained at the acid pH required for membrane fusion.

Animals↗
PubMed1986

Iron metabolism in the Belgrade rat.

Iron metabolism in the Belgrade rat was examined in the intact animal and in the reticulocyte suspensions. The plasma iron turnover was increased. However, when allowance was made for the effect of the elevated plasma iron concentration, erythroid marrow capacity for iron uptake was at basal levels. Numbers of erythroid cells in marrow and spleen measured by the radioiron dilution technique were increased. Thus iron uptake was not proportionate to the erythroid hyperplasia in the b/b rat, despite a more than adequate plasma iron supply. This relative deficiency in iron uptake was reflected in a severe microcytosis and elevated red cell protoporphyrin. Reticulocyte incubation studies demonstrated an unimpaired uptake of the transferrin-iron-receptor complex but a marked reduction in iron accumulation. The diferric transferrin molecule, when it did give up iron within the cell, released both of its iron atoms so that only apotransferrin was returned to the media. In contrast to the nearly complete release of iron within the normal reticulocyte, the major portion of iron taken up by the Belgrade reticulocyte was returned to the plasma. The release mechanism that can be impaired in iron-deficient reticulocytes by EDTA or cadmium was shown to be affected by lower concentrations of these substances in the Belgrade reticulocyte. It is concluded that the Belgrade rat has an abnormality of iron release within the absorptive vacuole that is responsible for a state of intracellular iron deficiency, involving the erythron and other body tissues.

Anemia, Hypochromic↗
PubMed1986

Clinical studies on the phenylethylamine hypothesis of affective disorder: urine and blood phenylacetic acid and phenylalanine dietary supplements.

To test the hypothesis that 2-phenylethylamine (PEA) modulates affect, plasma levels and urinary excretion of its main metabolite, phenylacetic acid (PAA), were studied in depressed and manic subjects, and the mood-elevating effects of its precursor, L-phenylalanine, were studied in depressed subjects. Mean total plasma PAA concentrations were 491.83 +/- 232.84 ng/ml in 12 healthy volunteers and 300.33 +/- 197.44 ng/ml in 23 drug-free patients with major depression. The 24-hour urinary PAA excretion was also measured in 48 healthy volunteers (141.1 +/- 10.2 mg PAA/24 hr) and in 144 patients with major depression (78.2 +/- 41.0 mg PAA/24 hr). The results suggest that low plasma and urinary PAA may be state markers for depression and are compatible with the PEA hypothesis. In further support, phenylalanine elevated mood in 31 of 40 depressives.

Adult↗
PubMed1985

Use of refined perinatal mortality rate trends to evaluate the effect of a confidential inquiry.

Standardised perinatal mortality rates and cause-specific rates were used to evaluate the effect of a confidential inquiry into perinatal deaths in West Glamorgan obstetric units. Cause of death was classified by means of 5 pathological subgroups, and the denominator data were obtained from the computerised standard child-health system. The standardised perinatal mortality rate fell from 103 in 1981 to 85 in 1983, and the perinatal mortality rate fell from 15.9 to 9.4 per 1000 births in that period; 3 of the cause-specific rates declined considerably. The trend indicates an improvement in antenatal care, obstetric management, resuscitation, and care in special-care baby units. An audit in the form of a confidential inquiry contributes to an improvement in health services and a consequent reduction in perinatal mortality.

Birth Weight↗
PubMed1985

Rainbow trout red cells in vitro.

Washed rainbow trout erythrocytes incubated at 14 degrees C in Eagle's minimal essential medium and Cortland saline displayed sharp reductions in volume and water content, nucleoside triphosphate, K+ and Cl- concentrations. Mg2+ and, to a lesser extent, Na+ concentrations increased. Cellular to medium Cl- ratios were indicative of membrane hyperpolarization. Morphological irregularities were also observed. Oxygen consumption and hemoglobin system organization were not grossly affected. Supplementation with pyruvate stabilized nucleoside triphosphate concentrations for at least 24 hr, and reduced rates of volume and compositional change to some extent. Addition of norepinephrine at physiologically realistic levels led to stabilization of Cl- content and reductions in Mg2+ accumulation and water loss. Transient but modest increases in K+ and Ca2+ were coupled, under these circumstances, with some decrease in Na+ concentration. Factors which may contribute to the dysfunctional status of these cells in vitro are discussed.

Animals↗