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Biomedical subjects

R Edwards

Publications and source records attributed to R Edwards.

At least 253 records · Page 14Linked to original sources
PubMed1991

Purification and characterization of S-adenosyl-L-methionine: caffeic acid 3-O-methyltransferase from suspension cultures of alfalfa (Medicago sativa L.).

Caffeic acid O-methyltransferase (COMT) is one of a group of proteins present in alfalfa cell cultures which can be photoaffinity labeled with S-adenosyl-L-[methyl-3H]methionine. The enzyme was purified to homogeneity from elicitor-treated suspension cultures and shown to exist as an active monomer of subunit Mr 41,000. COMT could be separated into two forms on the basis of their isoelectric points and relative affinities for S-adenosyl-methionine and S-adenosylhomocysteine. Both forms had equal affinities for caffeic acid, were highly specific for the 3-hydroxyl group of substituted cinnamic acids, and exhibited negligible activity toward flavonoid substrates. An antiserum raised against COMT from aspen immunoprecipitated alfalfa COMT activity. Peptide mapping studies indicated that the two forms of COMT and an isoflavone O-methyltransferase from alfalfa are closely related proteins. The extractable activity of COMT doubled over a 48-h period following exposure of alfalfa cell suspensions to a yeast elicitor preparation, and this was associated with a small change in the relative proportions of the two forms of the enzyme.

Affinity Labels↗
PubMed1991

Comparative susceptibility of cefminox and cefoxitin to beta-lactamases of Bacteroides spp.

The susceptibility of the new cephamycin antibiotic, cefminox, to hydrolysis by various types of beta-lactamase produced by organisms of the Bacteroides fragilis group was compared with that of cefoxitin. Several enzymes were able to achieve complete hydrolysis of both drugs during overnight incubation, but no marked difference between the rates of inactivation of cefminox and cefoxitin was observed. Susceptibility of the cephamycins to crude extracts of beta-lactamases from the test strains of Bacteroides spp. did not correlate with the results of conventional minimum inhibitory concentration titrations. Possible reasons for these discrepancies are discussed.

Bacteroides fragilis↗
PubMed1991

Perinatal outcome and congenital malformations in in-vitro fertilization babies from the Bourn-Hallam group.

The perinatal outcome and congenital malformations in children born between 1978 and 1987 in Great Britain after in-vitro fertilization (IVF) at Bourn Hall Clinic and the Hallam Medical Centre are presented. The average maternal age was 34.2 years. Multiple births were frequent, constituting 23% of all deliveries; 19% were twins and 4% triplets. There were no quadruplet or higher order multiple births during that period. Twenty-five per cent of all deliveries were preterm. The mean birth weight was 2793 g and was strongly related to multiplicity of pregnancy and gestational age. Overall, 32% of babies had a low birthweight (less than 2500 g) with 6% having a very low birthweight (less than 1500 g). The overall stillbirth and infant mortality rates were two to three times higher than those of infants born after natural conception in England and Wales; this is attributed to the high incidence of multiple births. The stillbirth rates were 5.07, 20.8 and 24.7 per thousand total births in singletons, twins and triplets respectively. The corresponding figures for perinatal mortality were 13.5, 38.2 and 37 per thousand. Overall, 2.5% of the babies had one or more major congenital malformations diagnosed within one week of life. This was within the range of expected values in the United Kingdom and there was no significant increase in any specific malformation.

Adult↗
PubMed1991

Urinary growth hormone excretion during puberty in type 1 (insulin-dependent) diabetes mellitus.

The excretion of urinary growth hormone was measured by a highly sensitive direct immunoradiometric assay in a cross-sectional study during puberty in 70 children with Type 1 (insulin-dependent) diabetes mellitus and 94 normal children. In normal children (n = 24) and diabetic children (n = 17) overnight urinary growth hormone excretion correlated significantly with the mean overnight plasma concentration (r = 0.70, p less than 0.001, and r = 0.70, p less than 0.001), indicating that urinary GH excretion reflects the circulating endogenous GH level. Overnight urinary growth hormone excretion increased during puberty. In normal and in diabetic children there was a peak in boys at genital stage 4 (both p less than 0.01), and in girls at breast stage 2 (both p less than 0.02). The diabetic children excreted more urinary growth hormone than the normal children at every pubertal stage. Excretion of albumin, retinol binding protein and N-acetyl-beta-D-glucosaminidase was measured in urine from 38 diabetic children. Urinary growth hormone correlated weakly with urinary albumin (r = 0.49, p less than 0.01), retinol binding protein (r = 0.42, p less than 0.01), and N-acetyl-beta-D-glucosaminidase (r = 0.43, p less than 0.01). Urinary GH excretion was not related to blood glucose control (HbA1) in boys (n = 31) or girls (n = 39). The measurement of urinary growth hormone provides an assessment of endogenous growth hormone during puberty in normal and diabetic children. However, caution must be exercised in interpreting urinary growth hormone data from diabetic patients with increased excretion of albumin and retinol binding protein.

Acetylglucosaminidase↗
PubMed1991

The use of cervicography in a primary screening service.

The cervicography and concurrent endocervical brush smear results obtained in 1162 women screened at the Marie Stopes Clinic were analysed. Colposcopy and biopsy results were obtained for positive cases. A comparison was made with a group of 1007 women attending the same clinic for routine cytology only. Nearly 10% of women who were screened by cervicography had a technically defective cervicogram, the main single reason being that the view was obscured by blood. Routine cytology was positive in 1%, while cervicography was positive in 13%, where positivity was defined as a result leading to a recommendation for colposcopy. The false positive rate for cervicography was 26%. Even after adjustment, this difference was highly significant (P less than 0.0001).

Acetates↗
PubMed1991

Assessment of psychiatric morbidity in patients attending a colposcopy clinic situated in a genitourinary medicine clinic.

OBJECTIVE: To determine the adverse psychological implications of referral for colposcopic screening within a genitourinary medicine clinic. DESIGN: Cross sectional survey. SETTING: A colposcopy clinic held within a genitourinary medicine clinic. SUBJECTS: 160 consecutive women referred to the clinic were assessed for psychiatric morbidity using the General Health Questionnaire (GHQ-28). Women were referred to the colposcopy clinic because of one or more of the following: abnormal cervical cytology, condylomata acuminata, HIV antibody positivity. A history of prior local ablative therapy to the cervix was also included in the analysis. RESULTS: There was no difference in psychiatric morbidity, as detected by the GHQ-28, in women referred to the clinic because of abnormal cervical cytology or condylomata acuminata. The total GHQ-28 scores indicated a significant increase in psychiatric morbidity, with increased sub-scores indicating social dysfunction, anxiety and somatic symptoms, in women who had had prior laser therapy to the cervix. Women with HIV infection attending the clinic were noted to have an increase in GHQ-28 sub-scores indicating social dysfunction and depression. CONCLUSIONS: Women who have undergone laser therapy to the cervix may benefit from psychological evaluation and supportive measures if they develop further genital lesions which require colposcopic evaluation. Women with HIV infection need further psychological evaluation prior to planning intervention and preventative strategies.

Anxiety Disorders↗
PubMed1991

Turbidimetric study of the effect of inoculum density on the response of Escherichia coli to gentamicin under aerobic and anaerobic conditions.

The turbidimetric response to gentamicin of two strains of Escherichia coli was examined under aerobic and anaerobic conditions with 3 inocula. Turbidimetry showed that the minimum inhibitory concentration (MIC) was influenced by growth of partially inhibited cultures during the overnight incubation period. Continuous turbidimetric monitoring also allowed the minimum antibacterial concentration (MAC: the lowest concentration to cause an effect on normal growth) to be measured. As judged by the MAC, the effect of inoculum was small over the range 5 x 10(5) to 9 x 10(7) colony-forming units (CFU), but increased substantially as the inoculum was raised further. Exposure to gentamicin under anaerobic conditions caused an average 4-fold rise in the MAC with different inocula.

Aerobiosis↗
PubMed1991

Clonazepam in acute mania: a double blind trial.

In a double-blind trial involving acutely manic patients, clonazepam was compared to placebo, both groups receiving chlorpromazine as needed. The group receiving clonazepam showed significantly more improvement in their manic but not their psychotic symptoms compared to the placebo group. This effect was not primarily related to the sedative effects of clonazepam. Clonazepam tended to reduce the need for phenothiazine medication. Side effects related to sedation were more common to the clonazepam group. These findings are the first to indicate that clonazepam may have a specific antimanic effect over and above that of phenothiazines alone.

Adolescent↗
PubMed1991

Additional evidence for functional subclassification of alpha-2 adrenoceptors based on a new selective antagonist, SK&F 104856.

SK&F 104856 (2-vinyl-7-chloro-3,4,5,6-tetrahydro-4-methyl-thieno[4,3,2ef][3] benzazepine) shows a similar selectivity profile to the previously reported alpha adrenoceptor antagonist, SK&F 104078 (6-chloro-9-[(3-methyl-2-butenyl)oxy]-3-methyl-1H-2,3,4,5-tetrahydro-3- benzazepine), having the ability to block alpha-1 and postjunctional alpha-2 adrenoceptors, although having little or no activity at most prejunctional alpha-2 adrenoceptors. SK&F 104856 is more potent than SK&F 104078, and lacks the 5-hydroxytryptamine receptor antagonist activity associated with the earlier compound. The postjunctional vs. prejunctional selectivity of SK&F 104856 at alpha-2 adrenoceptors in the same tissue preparation was demonstrated in both canine and human saphenous vein. Concentrations substantially higher than those required to block postjunctional alpha-2 adrenoceptor-agonist induced vasoconstriction had no effect on the ability of norepinephrine, acting on prejunctional alpha-2 adrenoceptors, to inhibit stimulation evoked transmitter overflow in the human tissue, and only a small effect in the canine vein. As observed with SK&F 104078, SK&F 104856 has some prejunctional alpha-2 adrenoceptor antagonist activity in the rat vas deferens, although the receptor dissociation constant is nearly 50-fold higher than that at the postjunctional alpha-2 adrenoceptor in the canine saphenous vein. The results obtained with SK&F 104856 provide additional evidence to support the premise that alpha-2 adrenoceptors can be functionally differentiated. Because SK&F 104856 can selectively antagonize certain alpha-2 adrenoceptor-mediated responses, this agent may be a useful tool to evaluate the functional roles of the multiple alpha-2 adrenoceptor subtypes that have been identified in biochemical and molecular studies.

Adrenergic alpha-Agonists↗
PubMed1991

Blood pressure patterns in the first three days of life.

Current blood pressure data for healthy newborn infants consist primarily of single measurements of systolic and diastolic pressure in the first 48 hours of life. The purpose of this study was to determine if blood pressure levels are stable or are changing during the first few days of life. To determine blood pressure level and trend, indirect blood pressure was measured on day 1 through day 3 of life in all infants admitted to the well newborn nursery at Hahnemann University Hospital in Philadelphia. Systolic pressure correlated significantly with birthweight on day 1 of life (P less than .03). Repeated measures analysis of variance demonstrated a significant increase in both systolic and diastolic pressures over the first 72 hours of life (P less than .001). There was no difference in blood pressure among racial groups (black, Hispanic, white, Asian). In healthy newborns, there was no correlation of blood pressure with maternal conditions: toxemia, diabetes, substance abuse. These data demonstrate that blood pressure correlates with birthweight in well newborns. There is, however, a significant progressive increase in both systolic and diastolic blood pressure over the first 3 days of life, regardless of birthweight or maternal conditions.

Analysis of Variance↗
PubMed1991

Agglutination of blood cardioplegia by cold-reacting autoantibodies.

Cold-reacting autoantibodies occasionally occur in patients requiring cardiac operations. This report describes the clinical course of 1 patient with cold-reacting autoantibodies and intracoronary agglutination of the blood cardioplegia solution. Observations made in vivo and in vitro are considered in discussing recommendations for the management of extracorporeal circulation and cardioplegic arrest in patients with clinically silent cold-reacting autoantibodies.

Aged↗
PubMed1990

Monitoring mutagenicity in urine and peripheral blood lymphocytes of pharmacists occupationally exposed to anticancer drugs.

Two approaches to mutagenicity monitoring were compared for estimation of possible absorption of cytotoxic drugs by a group of six pharmacists at Auckland Hospital. Blood samples were taken before and after a three week duty roster, from age and sex matched negative controls, and from a matched group of patients on chemotherapy. Peripheral blood lymphocytes were fixed, stained and analysed for sister chromatid exchange (SCE). Urine samples were collected from the pharmacists on the morning following their last day on cytotoxic dispensing duty, as well as from positive and negative controls. Samples were concentrated and analysed for mutagenicity in the bacterial Ames test. Comparison of negative control groups with the pharmacists using either of these test measures gave no evidence for significant absorption of cytotoxics by the pharmacist group as a whole, although values for the positive control groups were raised significantly in a similar comparison. The value for SCE of one pharmacist however, was elevated in the second sample (after three weeks dispensing duty) when compared with the first sample (before duty) and the urine analysis also suggested that this individual might have absorbed some mutagens. The results permit a comparison of these techniques as a means of ongoing monitoring of similar populations within New Zealand.

Antineoplastic Agents↗
PubMed1990

Abnormal plant development and down-regulation of phenylpropanoid biosynthesis in transgenic tobacco containing a heterologous phenylalanine ammonia-lyase gene.

Biosynthesis of phenylpropanoid natural products in tobacco was perturbed by introduction of a heterologous (bean) phenylalanine ammonia-lyase (PAL; L-phenylalanine ammonia-lyase, EC 4.3.1.5) gene, modified by inclusion of cauliflower mosaic virus 35S enhancer sequences in its promoter. These transgenic plants can exhibit a series of unusual phenotypes including localized fluorescent lesions, altered leaf shape and texture, reduced signification in xylem, stunted growth, reduced pollen viability, and altered flower morphology and pigmentation. Genetic analysis of a transformant with severe symptoms showed that symptom development was inherited as a single, partially dominant trait and cosegregated with reduced levels of PAL activity and soluble phenylpropanoid products. Accumulation of transcripts encoded by the endogenous tobacco PAL genes was suppressed. We conclude that the transgene disrupts PAL regulation and that some of the phenotypes reflect interference with putative signals dependent on phenylpropanoid biosynthesis.

Journal Article↗