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Biomedical subjects

C Edwards

Publications and source records attributed to C Edwards.

At least 289 records · Page 16Linked to original sources
PubMed1982

Is the transit time of a meal through the small intestine related to the rate at which it leaves the stomach?

Using non-invasive techniques, we investigated how varying the size or composition of a meal altered the rate at which it passed through the stomach and small intestine in normal volunteers. Increasing the size of the meal by doubling the absorbable components delayed gastric emptying, did not significantly influence the time taken for the head of the meal to reach the caecum, but retarded the entry of the bulk of the meal residues into the caecum. Incorporating fat in the meal slowed gastric emptying, but did not significantly affect small bowel transit time. The addition of the unabsorbable disaccharide lactulose (in place of an equivalent amount of sucrose) accelerated small bowel transit time, but did not significantly influence gastric emptying. Thus, our results indicated that changes in small bowel transit time could occur independently of changes in gastric emptying in normal healthy subjects.

Adult↗
PubMed1982

The presence of Schistosoma mansoni in Montserrat Leeward Islands.

Following the discovery in two villages in Montserrat of five individuals who were passing Schistosoma mansoni ova in their stools, a house to house survey was undertaken in November 1978 to determine the prevalence of the infection. From 158 persons residing in the two villages 137 faecal samples were received. Of these 14% were positive for S. mansoni ova. The enzyme linked immunosorbent assay (ELISA) was performed on finger-prick blood samples collected on chromatography paper. In the ELISA 16% of the 132 persons tested were positive. In comparison with the stool examination, the ELISA showed a 53% sensitivity and a 92% specificity. It was recommended that the individuals passing schistosome eggs should be treated.

Adolescent↗
PubMed1982

Examination of the regulation of the actin multigene family in Dictyostelium discoideum.

The Dictyostelium actin genes constitute a seventeen-member dispersed multigene family. At least nine of the seventeen genes are expressed. Nearly all of the genes seem to code for the same protein sequence, although one gene with a variant amino acid sequence is expressed. The 5' untranslated and untranscribed sequences as well as the 3' untranscribed sequences are not conserved from gene to gene, although TATA and poly(T) sequences are found in the region of transcription initiation. The 3' untranslated sequences are conserved within some groups of genes. This allows us to suggest an evolutionary history of the actin gene duplications. We have developed a DNA mediated transformation system for Dictyostelium. We will soon be able to use this system to examine the importance of various regions around the actin genes for proper control of gene expression and to identify sequences involved in developmental regulation.

Actins↗
PubMed1981

Concentrations of prolactin and luteinizing hormone in plasma of doves in relation to incubation and development of the crop gland.

The concentrations of prolactin and LH were measured in the plasma of male and female ring doves (Streptopelia risoria) during the breeding cycle. Prolactin concentrations were low during courtship and early incubation but increased markedly (P less than 0.01 in both sexes) between days 7 and 15 of incubation, during the period of rapid growth of the crop sac. Levels remained raised for 4 days after the young had hatched but then declined as the crop sacs gradually regressed. These observations showed that concentrations of prolactin were high at the time when the crop sacs were proliferating and producing 'milk' for feeding the young, but that there was no increase in prolactin secretion at the onset of incubation as occurs in ducks, hens and other birds. In samples taken from doves at various times of the day and night there was no increase in plasma prolactin during the first few days of incubation. Concentrations of LH in plasma were generally higher in male doves than in females, but in both sexes were significantly higher during courtship than during incubation and brooding the young. Concentrations increased again when the young were independent and the parents began a second round of courtship.

Animals↗
PubMed1981

The distribution of a specific HLA-B27-associated cell surface component on the tissues of patients with ankylosing spondylitis.

In this paper, we report the presence on Epstein-Barr virus-transformed lymphoblastoid cell lines on platelets and on fibroblasts of an HLA-B27-associated cell surface complex (antigenically related to some antigens of Klebsiella K43 and K21) which is identical to or cross-reactive with the determinant present on the peripheral blood lymphocytes (PBL) of B27-positive patients with ankylosing spondylitis (AS). By contrast, no Klebsiella K43 markers could be demonstrated on the spermatozoa of B27+ AS+ individuals even though these cells expressed the HLA-B27 alloantigen. No B27-associated K43 antigen was detected on the erythrocytes of patients or of normal controls. The B27-associated membrane marker is still detectable on lymphoblastoid cell lines after 20 generations and on fibroblasts after about 10 generations. This finding implies that the continued expression of Klebsiella-modified B27 structure is generally determined and does not require the repeated exposure of the cell surface to Klebsiella antigen. These data suggest that certain non-lymphoid as well as lymphoid cells may be involved in the complex sequence of events leading to the clinical manifestation of AS.

Blood Platelets↗
PubMed1981

Blood pressure measurement by pharmacists.

The feasibility of blood pressure measurement by general practice pharmacists was examined in nine pharmacies. Two hundred and fifteen subjects were screened and 13 were referred to their general practitioners. Ten subjects (five per cent of the initial sample) were confirmed to be hypertensive by their doctors. The upper limits of normotension were 160/100 mmHg aged up to 50 years, 160/105 mmHg aged 51-60 years and a diastolic pressure of 110 mmHg over 60 years. Ninety-eight per cent of a sample of the lay public who completed a written questionnaire were in favour of blood pressure measurement by pharmacists. The study showed that general practice pharmacists were able to measure blood pressure within acceptable limits of accuracy and that, with the collaboration of general practitioners, the pharmacies were suitable agencies for screening for hypertension.

Adult↗
PubMed1980

Effects of anesthetic treatment on motor neuron death in xenopus.

Xenopus tadpoles were introduced into anesthetic (chlorbutanol) solutions during a developmental period in which naturally occurring loss of lumbar spinal motor neurons takes place. Animals that developed in these solutions were sacrificed after various lengths of time and the number of lumbar motor neurons were counted. No significant difference was detected between experimental and control motor neuron counts throughout the period in which most of the cells are normally lost. A similar finding is reported when one or more lumbar spinal nerves were blocked locally with implants of anesthetic (procaine) impregnated silastic chips.

Animals↗
PubMed1980

Sensitivity of synchronous cultures of Bacillus subtilis to lysozyme.

Rates of lysis by lysozyme (expressed as the decrease in A550 min-1) of synchronously dividing cells of Bacillus subtilis rose in concert with the stepwise increase in cell numbers. Asynchronously growing cells showed no periodicities in sensitivity; rates of lysis reflected the exponential increase in culture density.

Bacillus subtilis↗
PubMed1980

Comparison of a paper pill with a conventional oral contraceptive tablet.

A multicentre clinical trial comparing a novel formulation (the Paper Pill) of a combined oral contraceptive containing 30 microgram ethinyloestradiol and 150 microgram levonorgestrel with a conventional tablet formulation (Microgynon 30) has been carried out in 336 women over 6 cycles. There were no pill failures in women taking either preparation with one exception in the Microgynon 30 group which was due to poor patient compliance. Cycle control judged by cycle length, duration and amount of withdrawal bleeding and the incidence of intermenstrual bleeding was good in both groups. The number of adverse effects was slightly less in the Paper Pill group and fewer withdrawals for questionnaire reasons were noted than in the Microgynon 30 group. A questionnaire showed that the Paper Pill was accepted well by the majority of women in the trial.

Administration, Oral↗
PubMed1980

A malaria outbreak due to Plasmodium malariae on the Island of Grenada.

An outbreak of Plasmodium malariae malaria occurred in Grenada some 16 years after the end of a malaria eradication campaign, probably due to renewal of transmission from recrudescent cases. Serological studies were used in addition to blood film surveys in defining the outbreak, and their value in such surveillance situations is emphasized.

Adolescent↗
PubMed1979

Genetic linkage between hereditary hemochromatosis and HLA.

A large Mormon pedigree of a proband with hemochromatosis was studied, using transferrin saturation as the quantitative phenotypic trait. The analysis indicated that the inheritance of hemochromatosis was recessive, with partial expression in some heterozygotes. The lod score of 6.88 (theta = .0) was strongly indicative of linkage between the hemochromatosis locus and the human major histocompatibility (HLA) loci.

Chromosome Mapping↗
PubMed1978

The properties of adenosine triphosphatase from exponential and synchronous cultures of Alcaligenes eutrophus H16.

The properties of Alcaligenes eutrophus ATPase (adenosine triphosphatase) were investigated by using subcellular fractions prepared from cells growing in exponential and synchronous cultures. Both the soluble and membrane-bound forms of the ATPase were inhibited non-competitively (K(i) 142mum) by Nbf-Cl (4-chloro-7-nitrobenzofurazan), whereas only the membrane-bound enzyme was inhibited (non-competitive; K(i) 750mum) by NN'-dicyclohexylcarbodi-imide. Neither the activity of the ATPase nor its sensitivity to these two inhibitors varied during exponential growth. However, marked variations in ATPase activity were observed during synchronous growth, which were characterized by maxima at approx. 0.4 and 0.9 of a cell cycle and minima at approx. 0.1 and 0.6 of a cycle. Sensitivity to Nbf-Cl and NN'-dicyclohexylcarbodi-imide also varied during the cell cycle; maximum inhibition by the former occurred at approx. 0.4 and 0.9 of a cell cycle, whereas maximum inhibition by the latter was located at approx. 0.1 and 0.6 of a cell cycle. Proton conductance by whole cells was also periodic during the cell cycle, the lowest rates occurring at approx. 0.15 and 0.55 of a cycle and the highest rates at approx. 0.4 and 0.9 of a cycle, but -->H(+)/O quotients for the oxidation of endogenous substrates remained relatively constant and indicated the presence of four proton-translocating respiratory segments throughout the cell cycle. These results are discussed in terms of ATPase and respiratory-chain structure and function during the cell cycle of Alcaligenes eutrophus.

4-Chloro-7-nitrobenzofurazan↗
PubMed1978

Effects of organophosphate insecticides on the cholinergic receptors of frog skeletal muscle.

The organophosphates octamethyl pyrophosphoramide, Bidrin, and phosphoric acid 2,2-dichlorovinyl dimethyl ester inhibit the membrane voltage response of frog sartorius muscles to carbamylcholine in a manner expected of either a slowly reversing competitive inhibitor or a noncompetitive inhibitor. The inhibition reverses with a time course of minutes, depending upon the temperature. The inhibition by these compounds is reduced by d-tubocurarine but is unaffected by hexamethonium. This may indicate that the organophosphate binding sites are near the cholinergic binding site since both d-tubocurarine and hexamethonium are competitive inhibitors of cholinergic agonists and d-tubocurarine is the larger compound.

Acetylcholine↗