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Biomedical subjects

J Barker

Publications and source records attributed to J Barker.

At least 127 records · Page 7Linked to original sources
PubMed1985

Chloramphenicol alone versus chloramphenicol plus penicillin for bacterial meningitis in children.

367 children with cerebrospinal-fluid findings suggestive of bacterial meningitis were randomised to receive either chloramphenicol alone by intramuscular injection, or chloramphenicol plus penicillin by intravenous injection. Sequential analysis showed no difference in mortality between the two treatments. 48 (26%) of the 183 children in the chloramphenicol alone group died, and 49 (27%) of the 184 children in the chloramphenicol plus penicillin group died. In children with bacterial meningitis chloramphenicol alone given by intramuscular injection is as effective as chloramphenicol plus penicillin given intravenously.

Bacterial Infections↗
PubMed1985

Chloramphenicol alone versus chloramphenicol plus penicillin for severe pneumonia in children.

748 children with severe pneumonia in three hospitals in Papua New Guinea were randomised to receive intramuscular injections of either chloramphenicol alone or chloramphenicol plus penicillin. Sequential analysis showed no difference between the two treatments. 48 (13%) of the 377 children in the chloramphenicol alone group died, and 3 (0.8%) were changed to different treatment. 62 (17%) of the 371 children in the chloramphenicol-plus-penicillin group died, and 6 (1.6%) were changed to different treatment. The difference in failure rates (death or withdrawal for change of treatment) was 4.8% +/- 5.2% (+/- 95% confidence limits). In children with severe pneumonia, treatment with chloramphenicol alone is as effective as treatment with chloramphenicol plus penicillin.

Child↗
PubMed1985

Absorption of chloramphenicol sodium succinate after intramuscular administration in children.

Because it is thought that chloramphenicol is poorly absorbed after intramuscular administration, we compared blood levels of chloramphenicol after intramuscular administration with those after intravenous administration in children with a variety of diagnoses. Fifty-seven children were studied on 62 occasions while they were receiving chloramphenicol sodium succinate (25 mg of chloramphenicol per kilogram of body weight) intramuscularly every six hours. The peak level of chloramphenicol was 19.5 +/- 5.99 micrograms per milliliter (mean +/- S.D.) in 11 children after the first dose and 31.4 +/- 12.99 micrograms per milliliter in 51 children after two or more doses. The lowest peak level after intramuscular administration was 13 micrograms per milliliter, which is in the therapeutic range of 10 to 30 micrograms per milliliter. Thirteen children were studied on 17 occasions while they were receiving chloramphenicol sodium succinate (25 mg of chloramphenicol per kilogram) intravenously every six hours. The peak level of chloramphenicol was 19.4 +/- 6.37 micrograms per milliliter in eight children after the first dose and 28.2 +/- 11.09 micrograms per milliliter in nine children after two or more doses. The area under the serum level curve was not significantly different after intramuscular and intravenous administration. We conclude that chloramphenicol sodium succinate is well absorbed after intramuscular administration. This route is cheaper, it demands less staff time, and it does not carry the risks of sepsis and overhydration associated with intravenous therapy.

Absorption↗
PubMed1985

The activity of imipenem on Legionella pneumophila, with a note on the treatment of two cases.

An in-vitro assessment of the activity of imipenem, a new carbapenem beta-lactam antibiotic, was undertaken on isolates of Legionella pneumophila. The minimum inhibitory concentrations of imipenem were in the range 0.03 to 0.25 mg/l and turbidimetric studies showed that imipenem had a marked bactericidal effect which was more pronounced than that seen with either rifampicin or erythromycin. Two patients with legionella pneumonia were successfully treated with imipenem as part of a clinical trial of the drug.

Dose-Response Relationship, Drug↗
PubMed1985

The aetiology of purulent meningitis in highland children: a bacteriological study.

Of 155 highlands children with purulent culture-positive meningitis studied from March 1980 to September 1984, 84% were aged twelve months or less and 92% were infected with either Haemophilus influenzae, Streptococcus pneumoniae or both organisms. Other pathogens were Neisseria meningitidis (8 isolations), Streptococcus pyogenes (2 isolations) and Streptococcus agalactiae and Klebsiella species (1 of each). Among H. influenzae isolates, serotype b strains predominated (83%) and most (96%) belonged to biotype I or II. Infections due to non-b haemophili included serotype a (9 strains), serotype f (1 strain) and non-serotypable variants (3 strains). Of 67 S. pneumoniae strains 22% were resistant to benzylpenicillin, with minimal inhibitory concentrations of 0.1-1.0 micrograms/ml. The commonest serotypes were types 5 (11 isolates), type 7 (9 isolates) and types 2, 6 and 46 (6 of each). No resistance to chloramphenicol was detected in either H. influenzae or S. pneumoniae and only one of 56 strains of H. influenzae was insensitive to betalactam antibiotics. The known case fatality rate in this study was 37%. More children with pneumococcal infection died (46%) than those with haemophilus infection (30%), though the difference was not statistically significant; 79% of all deaths occurred in children aged less than twelve months. There is an urgent need for H. influenzae and S. pneumoniae vaccines that are effective in young children.

Age Factors↗
PubMed1984

Alpha thalassaemia in Papua New Guinea.

Haemoglobin Bart's was detected in cord blood samples from 81% of 217 infants born in Madang on the north coast of Papua New Guinea. Analysis of the alpha globin genes of 30 infants and adults from the same region showed that all but 3 were heterozygous or homozygous for the deletion form of alpha + thalassaemia. None of 18 cord blood samples from infants born in Goroka in the Eastern Highlands Province had haemoglobin Bart's, and in each case the alpha globin genes were normal. Preliminary geographical and linguistic analyses of both groups suggest that the prevalence of alpha thalassaemia may be related to altitude rather than to linguistic grouping and hence that resistance to malaria may be at least one reason why alpha thalassaemia is so common in some populations.

ABO Blood-Group System↗
PubMed1984

Alloxan-induced diabetes in the rat - protective action of (-) epicatechin?

Administration of alloxan (150 mg/kg body weight, i.p.) to male Wistar rats induced a reproducible and persistent diabetes mellitus as evidenced by elevated serum glucose and low serum insulin concentrations. Administration of either (-)epicatechin or (+)catechin (250 mg/kg, i.p. on each occasion) at 36, 24, 12 and 1 hour before and at 12 and 24 hours after alloxan administration did not prevent the induction of the diabetes. Similarly, treatment of animals with (-)epicatechin or (+)catechin (125 mg/kg i.p. twice daily) for 21 days commencing 24 hours after alloxan administration did not reverse the persisting elevated serum glucose and low serum insulin concentrations. Moreover, administration of these compounds did not relieve any of the symptoms of the alloxan-induced diabetes such as poor weight gain, polyuria or polydipsia. Thus, this study does not confirm previous reports of prophylactic and curative effects of (-)epicatechin against alloxan-induced diabetes in rats, in spite of the high dosages of the compounds used in these experiments.

Animals↗
PubMed1984

Issues in the in vivo measurement of glucose metabolism of human central nervous system tumors.

Over 150 cases of central nervous system tumors have been studied with positron emission tomography using fluorine-18-labeled fluorodeoxyglucose (18FDG) as a tracer. From this material 100 consecutive cases of cerebral glioma have been reviewed and analyzed. The results show a strong correlation of tumor grade with glycolytic rate, with visual "hot spots" present in all high-grade neoplasms and in only four low-grade tumors. The quantitative accuracy is limited by three basic factors. First, the measurement of tissue uptake, as compared with the parent technique, autoradiography, is more difficult because detection must be done outside the body. Effects such as scattered radiation and self-attenuation introduce errors unless properly corrected. A more serious problem when measuring small structures, such as a rim-shaped high-grade glioma, is the limited spatial resolution. The most advanced scanner, the Neuro-PET, has a resolution of 6 to 7 mm. Second, corrections are needed for backflow, including free tracer at the time of the scan that will return to the blood and "trapped" tracer that will backflow because of the presence of phosphatase. These corrections are calculated from the blood activity using nominal rate constants for 18FDG. Our study found no significant alteration in rate constants between normal and tumoral tissue. Finally, a lumped constant is needed to correct for kinetic differences between 18FDG and glucose. If there is a change in the mechanism of either membrane transport or the hexokinase reaction, the lumped constant may change. However, measurements of actual glucose utilization in tissue culture lines from six patients support the 18FDG results.

Animals↗