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Biomedical subjects

G Roberts

Publications and source records attributed to G Roberts.

At least 163 records · Page 9Linked to original sources
PubMed1989

Timing and purpose of the MRCGP examination.

There is increasing disquiet among course organizers about trainees who sit the MRCGP examination before completing vocational training. An alternative arrangement is proposed for trainees to undergo continuous assessment during vocational training with a more clinical end-point assessment than the current MRCGP examination. Career progression for general practitioners would then be available in the form of the MRCGP examination after a number of years in practice and the FRCGP by assessment at a later stage. It is suggested that the government might wish to reward evidence of a commitment to continuing education.

Educational Measurement↗
PubMed1988

Effect of vitamin and mineral supplementation on intelligence of a sample of schoolchildren.

90 schoolchildren aged twelve and thirteen years kept a dietary diary for three days. In most cases the average intake of vitamins was close to the recommended daily allowance, although for a minority the intake was low; with minerals the recommended daily allowance was less commonly achieved. To examine the possibility that deficiency of dietary minerals and vitamins was preventing optimum psychological function, a multivitamin/mineral supplement or a placebo was administered double-blind for eight months to 60 of the children. The supplement group, but not the placebo group or the remaining 30 who took no tablets, showed a significant increase in non-verbal intelligence.

Child↗
PubMed1988

In-vitro activity of ofloxacin against isolates of Neisseria gonorrhoeae.

A total of 1186 clinical isolates of Neisseria gonorrhoeae were tested for in-vitro disc susceptibility to ofloxacin, one of the new generation of fluorinated quinolones. All isolates appeared susceptible. Minimum inhibitory concentrations were determined for a random sample of 122 strains and all were equal to or less than 0.02 mg/l.

Female↗
PubMed1988

Lack of effect of erythromycin on the pharmacokinetics of single oral doses of phenytoin.

The effect of erythromycin on the pharmacokinetics of phenytoin was studied in eight healthy volunteers using a balanced randomised cross-over design. Volunteers received a single oral dose of 400 mg of phenytoin sodium during each phase. During the treatment phase, the phenytoin sodium dose was administered 4.5 days after the commencement of a 7 day course of erythromycin base (250 mg every 6 h). There was no significant difference between the control and treatment phases (P greater than 0.05) with respect to the area under the plasma phenytoin concentration-time curve, the fraction of phenytoin unbound in plasma, the area under the unbound phenytoin concentration-time curve, the elimination half-life of phenytoin or the fraction of the dose excreted in urine as free and conjugated hydroxyphenylphenylhydantoin. This single dose study indicated that the intrinsic clearance of unbound phenytoin was unaffected by the concurrent administration of erythromycin.

Administration, Oral↗
PubMed1988

Screening for cystic fibrosis: a four year regional experience.

A four year regional screening programme to detect cystic fibrosis using measurement of immunoreactive trypsinogen is described. During this period 60 infants were diagnosed; 34 by screening, 12 born with meconium ileus, and 14 not identified by the screening assay but who presented with clinical symptoms at a later age, giving an incidence of cyst fibrosis in the region during this time of 1/1807. Screening has resulted in earlier detection of cystic fibrosis in many infants, thus allowing treatment to be instituted at an early age, and genetic counseling offered to the parents. There were a number of false positives and false negatives with the immunoreactive trypsinogen screening assay. In addition, eight infants who were sweat tested at an early age had a sweat sodium concentration of less than 70 mmol/l, although they were subsequently shown to have cystic fibrosis. These results confirm other published data showing that sweat sodium results may be low in very young infants with cystic fibrosis. At the time of diagnosis seven (20%) of the infants identified by screening were totally asymptomatic and several additional children had symptoms of such a type that the diagnosis of cystic fibrosis had not been considered at the time of screening. Despite the problems experienced it has been decided to continue screening.

Age Factors↗
PubMed1988

Isolation and structure determination of Pachybasium cerebrosides which potentiate the antifungal activity of aculeacin.

A set of four cerebrosides was isolated from a Pachybasium species and purified by preparative reversed-phase HPLC. All four products displayed activity in a natural product screen aimed at detecting novel cell wall-active antifungal agents based on synergy with the known glucan synthetase inhibitor, aculeacin. Based on degradation studies, fast atom bombardment mass spectrometry and 13C and high field 1H NMR techniques, the structure of the major cerebroside was determined to be (4E,8E)-N-D-2'-hydroxy-(E)-3'- hexadecenoyl-1-O-beta-D-glucopyranosyl-9-methyl-4,8-sphingadiene. The other components were found to be the corresponding 2'-hydroxypalmitic acid analog with one less double bond and an analogous pair containing 2'-hydroxystearic acid with and without the 3' double bond.

Antifungal Agents↗
PubMed1987

Video EEG telemetry using an ambulatory EEG cassette recorder.

A system of video/EEG monitoring is described which is complementary to out-patient ambulatory EEG recording and prolonged hospital admission for intensive assessment. An ambulatory EEG cassette recorder is incorporated in the system which increases the usefulness of this equipment. In addition all the recorded EEG may be rapidly reviewed. This system has proved valuable in the management of selected patients seen in a special clinic for epilepsy.

Electroencephalography↗
PubMed1987

Characterization of suppressible mutations in the viomycin phosphotransferase gene of the Streptomyces enteric plasmid pVE138.

The viomycin phosphotransferase gene (vph) is expressed and confers resistance to viomycin in both Streptomyces spp. and members of the family Enterobacteriaceae. We report the isolation of UGA (opal) and UAG (amber) mutations in the vph gene of shuttle plasmid pVE138. We found that the five UGA mutations in vph resulted in a temperature-sensitive phenotype in Salmonella typhimurium. Su- strains are Vior at 28 degrees C and Vios at 37 degrees C, whereas Su+UGA strains are Vior at both 28 and 37 degrees C. The single amber mutation isolated was not temperature sensitive and resulted in the expected Vios phenotype in Su- strains and Vior in Su+UAG strains.

DNA Restriction Enzymes↗
PubMed1985

Selective Isolation of Bacillus sphaericus from Soil by Use of Acetate as the Only Major Source of Carbon.

A simple chemically defined medium containing sodium acetate (37 or 74 mM) as the only major source of carbon was inoculated with soil from various locations. The bacteria which grew most rapidly at 30 degrees C were almost entirely strains of Bacillus sphaericus and Arthrobacter species. Pasteurization of the soils made the medium selective for B. sphaericus. Several new strains were isolated, and the peptidoglycans of their cell walls were examined.

Journal Article↗
PubMed1984

Subclavian flap repair of coarctation of the aorta in neonates. Realization of growth potential?

The subclavian flap repair for coarctation of the aorta allows potential for growth by utilizing autogenous tissue. Although well documented in young children, its promise in the tiny neonate warrants further evaluation. Since August, 1979, 29 patients, including 24 infants, have undergone subclavian flap repair at the University of Maryland Hospital. Weights ranged from 1.4 to 5 kg (mean 3.2 kg). All patients less than 6 months old had associated intracardiac defects and were in severe congestive failure. Fifteen responded to preoperative prostaglandin infusions. The overall early mortality was 14%; among the neonates it was 21%; and among those operated upon within the first week of life, 33%. There was one intraoperative death among the eight patients who underwent simultaneous pulmonary artery banding. There were no deaths among patients older than 5 days at operation. Four of the five neonates who died had some variant of hypoplastic left heart syndrome, with severe stenosis or atresia of the systemic atrioventricular valve, critical aortic stenosis, or hypoplastic left ventricle. Twenty-two survivors continue to do well up to 3.7 years postoperatively (mean follow-up 26 months). At follow-up all patients are normotensive with brisk lower extremity pulses. Patients now weigh 1.3 to 6.9 (mean 2.3) times their operative weight, and only one patient has a measured arm-to-leg gradient greater than 10 mm Hg (mean gradient 3.7 mm Hg). Seven of the neonates have undergone repeat catheterization, and all had satisfactory growth of the subclavian flap segment of repair and no gradient. Two older patients (3 and 4 years old at operation) have undergone exercise testing 3.7 years after repair, with peak exercise gradients of only 7 and 15 mm Hg. We therefore continue to utilize this technique for the treatment of coarctation even in tiny neonates.

Aortic Coarctation↗
PubMed1982

Melanoma in New South Wales 1970-76: surgical therapy and survival.

From a survey of melanoma cases in New South Wales, a random sample was selected for histopathological review and follow up concerning surgical therapy and survival. It was found that the principal factors influencing survival were tumour thickness, level of mitotic activity and the age of the patient. The form of treatment in many cases bore little relationship to the severity of the tumour, as determined by its thickness, or to survival. It is hypothesised that survival rates would be higher and unnecessarily extensive surgery avoided if treatment were chosen with greater regard to established prognostic indicators.

Adult↗
PubMed1982

Polarity in the glnA operon: suppression of the reg- phenotype by rho mutations.

To determine the ability of mutations in glnA, the gene for glutamine synthetase (GS), to regulate nitrogen assimilatory enzymes, we assayed histidase and GS in 34 glnA (Gln(-)) strains. Twenty-five glnA mutants were RegC, synthesizing high levels of histidase regardless of the availability of nitrogen, and nine were Reg(-), synthesizing low levels of histidase in medium containing either limiting or excess ammonia. rho mutations were introduced into strains containing glnA point mutations or insertions in glnA, glnL, glnG, or glnF. The Reg(-) phenotype of strains with glnA point mutations, but not those with glnA or glnF insertions, was altered by the presence of rho, suggesting that glnA (Reg(-)) mutations are polar and exert their phenotype by decreasing expression of glnL and glnG. Consistent with this view, no GS protein was detected by two-dimensional gel electrophoresis in glnA (Reg(-)) rho(+) or glnA (Reg(-)) rho double mutants, whereas GS protein was detected in cells of 10 of 11 glnA (RegC) strains. Since glnA (Reg(-)) rho double mutants synthesize constitutive levels of histidase, GS protein is not necessary for full expression of histidase. Mu d1 insertions in glnL, but not those in glnG, responded to the presence of a rho allele, presumably owing to elevated transcription into glnG from the Mu d1 prophage. Our results suggest that glnA (Reg(-)) alleles are polar mutations, and a rho-dependent termination site down-stream is postulated as the basis for the polar phenomenon. The data also indicate that, under some circumstances, a significant portion of glnL and glnG transcription is initiated at the glnA promoter.

DNA, Recombinant↗