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Biomedical subjects

G Thompson

Publications and source records attributed to G Thompson.

At least 91 records · Page 5Linked to original sources
PubMed1989

A comparison of audiometric test methods for 2-year-old children.

Visual reinforcement audiometry (VRA), visual reinforcement operant conditioning audiometry (VROCA), and play audiometry were compared in terms of conditionability and number of responses obtained prior to habituation on normal 2-year-old (24-27 months) children. Results indicated that a higher percentage of children could be conditioned to VRA than to either VROCA or play audiometry. Results also indicated that for children who could be conditioned, the play audiometry group showed more responses prior to habituation than were obtained from the other two groups.

Age Factors↗
PubMed1989

Defects in the low density lipoprotein receptor gene affect lipoprotein (a) levels: multiplicative interaction of two gene loci associated with premature atherosclerosis.

The lipoprotein (a) [Lp(a)] contains two nonidentical protein species, apolipoprotein (apo) B-100 and a specific high molecular weight glycoprotein, apo(a). Lp(a) represents a continuous quantitative genetic trait, the genetics of which are only poorly understood. Genetic variation at the apo(a) locus affects plasma Lp(a) levels and explains at least 40% of the variability of this trait. Lp(a) levels were found to be elevated 3-fold in the plasma from patients with the heterozygous form of familial hypercholesterolemia who have one mutant low density lipoprotein receptor gene. This elevation was not due to a higher frequency of those apo(a) types that are associated with high Lp(a) levels in familial hypercholesterolemia patients. Rather Lp(a) levels were elevated for each of the apo(a) phenotypes examined. The effects of the apo(a) and low density lipoprotein receptor genes on Lp(a) levels are not additive but multiplicative. This is a situation not commonly considered in quantitative human genetics. We conclude that Lp(a) levels in plasma may be determined by variation at more than one gene locus.

Arteriosclerosis↗
PubMed1988

Therapeutic modification of membrane lipid abnormalities in juvenile neuronal ceroid-lipofuscinosis (Batten disease).

Five patients with juvenile neuronal ceroid-lipofuscinosis, who were shown to have absent or reduced serum prebetalipoprotein and a deficiency of polyunsaturated fatty acids in erythrocyte membrane lipids, were treated for a period of one year with supplements of fish oil extract (rich in omega-3 fatty acids) and encouraged to increase dietary intake of corn oil lipid (rich in omega-6 fatty acids) in an attempt to promote incorporation of these fatty acids into membranes. After one year there was a significant increase in omega-3 fatty acids (P less than 0.05) and in the total polyunsaturated fatty acids (P less than 0.02) in erythrocyte membranes but no change in the incorporation of omega-6 fatty acids. The patients were assessed clinically, psychometrically and neurophysiologically before and after the supplementation. No significant changes were noted after one year of treatment.

Adolescent↗
PubMed1988

Pyruvate dehydrogenase activity in osmotically shocked rat brain mitochondria: stimulation by oxaloacetate.

Pyruvate dehydrogenase complex activity (PDHC) measured by CO2 release isotopic assay has generally been much lower than activity measured by the spectrophotometric arylamine acetyltransferase assay (ArAT). Decarboxylation of [1-14C]pyruvate was measured in osmotically shocked rat brain cortical mitochondria. Activity is dependent on the concentration of the substrate pyruvate. Activity of 74.6 units +/- 12.3 SD (n = 22) was observed at 4 mM pyruvate (1 unit = 1 nmol pyruvate decarboxylated/min/mg protein). Activity was dependent on added NAD, CoA, and thiamine pyrophosphate, implying increased mitochondrial permeability after osmotic shock. Freeze/thaw with sonication of the mitochondrial preparation reduced PDHC activity to 11.5 units +/- 3.0 SD (n = 4). Oxaloacetate produced a marked stimulation of activity. The optimal assay contained 3 mM oxaloacetate, and without oxaloacetate activity fell to 15.4 units +/- 9.9 SD (n = 8). These studies highlight the importance of optimal substrate concentrations in the CO2 release isotopic PDHC method. Higher PDHC activity is found with intact mitochondria and thus activity values should be interpreted in the light of the presence or absence of intact mitochondria in individual preparations.

Animals↗
PubMed1987

Time for a stock-aid.

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Central Supply, Hospital↗
PubMed1987

Phase I trial and pharmacokinetic study of intravenous and oral alpha-difluoromethylornithine.

Eflornithine-HCl (alpha-difluoromethylornithine or DFMO), an irreversible inhibitor of ornithine decarboxylase, blocks polyamine synthesis and has demonstrated antitumor activity in cell culture and animal tumor models. This phase I study was designed to determine and compare toxicity and the maximally tolerated dose of a 4-day course of DFMO given to patients in oral, continuous intravenous infusion or pulse intravenous infusion forms. Twenty-four patients were entered into this study: 8 received intravenous pulse drug, 10 intravenous continuous infusion of drug, and 6 oral DFMO. The most frequent toxicity was nausea and vomiting which occurred in 9 courses of oral drug. Only two patients receiving intravenous DFMO had nausea and vomiting. Clinically significant thrombocytopenia and audiometric abnormalities were not encountered in contrast to previous experience with 28-day courses of oral DFMO. The maximally tolerated dose of a four-day course of oral DFMO was 3.75 gm/M2 every 6 hours. The maximally tolerated dose of intravenous pulse and continuous infusion DFMO was not attained. Pharmacokinetic studies demonstrated that the intravenous schedules achieved higher plasma levels of DFMO than those previously obtained with chronic oral dosing.

Administration, Oral↗
PubMed1987

Evaluation of Quantum II microbiology system for identification of gram-negative bacteria of veterinary origin.

The ability of a rapid, semiautomated bacterial identification system, the Quantum II microbiology system (Abbott Laboratories, Irving, Tex.), to accurately identify gram-negative bacteria from veterinary sources was evaluated. A total of 378 isolates were tested, including 298 organisms in the family Enterobacteriaceae and strains representing Acinetobacter sp., Aeromonas sp., Flavobacterium sp., Pasteurella multocida, Plesiomonas sp., and Pseudomonas spp. Of these isolates, 333 (88.1%) were correctly identified, 20 (5.3%) were not identified, 10 (2.6%) were incorrectly identified at the genus level, and 15 (4.0%) were incorrectly identified at the species level. The Quantum II system correctly identified 268 (89.9%) of the isolates of Enterobacteriaceae and 65 (81.3%) of the nonenteric isolates. P. multocida was not identified correctly, and some nonenteric gram-negative bacteria of clinical significance in veterinary medicine are not included in the data base. The Quantum II system provided an accurate identification system for isolates of Enterobacteriaceae but had limited usefulness for the identification of other gram-negative bacteria of clinical significance in veterinary medicine.

Animals↗
PubMed1987

Auditory brainstem responses in young adults with Down syndrome.

Auditory brainstem response (ABR) wave V detection levels, latency, and amplitude were studied in a group of 15 young adults with Down syndrome for whom behavioral measures of hearing sensitivity were also obtained. Comparisons were made to a group of nonretarded control subjects matched by age and sex. Auditory brainstem response detection levels were elevated, response amplitude was reduced, and latency-intensity functions were significantly steeper for the subjects with Down syndrome than for the control group. These findings were associated with a high frequency (8000 Hz) hearing loss prevalent in the otherwise normal-hearing experimental group.

Adolescent↗
PubMed1987

A comparative study of cefotetan and metronidazole against metronidazole alone to prevent infection after appendectomy.

The role of metronidazole in reducing the incidence of infectious complications after appendectomy has been established, but the value of an additional antibiotic to act against aerobic pathogens remains controversial. Patients who received 2 grams of cefotetan intravenously at the time of appendectomy and those who did not were compared for the incidence of infection. All patients received 1 gram of metronidazole per rectum preoperatively and every 12 hours for five days postoperatively. Infection occurred in three patients who received cefotetan and 16 of those who did not (p less than 0.01). We conclude that a single dose of cefotetan, an antibiotic which is effective against aerobic and anaerobic organisms, produces a significant reduction in the incidence of infection when added to metronidazole in the management of patients after appendectomy.

Adolescent↗
PubMed1986

Assessment of non-mydriatic fundus photography in detection of diabetic retinopathy.

Non-mydriatic retinal photography with later interpretation of the photographs was assessed as a screening method for the detection of diabetic retinopathy; when compared with an ophthalmologist's clinical assessment in a random group of 62 diabetic patients it was accurate (false negative 6.8%, false positive 2%) and sensitive (sensitivity 96%, specificity 98%). The assessment of further management required based on analysis of the photographs was 96.5% in agreement with the further management suggested by the ophthalmologist after direct clinical assessment of the patient. If this technique were used to screen patients in a typical diabetic clinic the predicted positive accuracy rate would be 84% and the predicted negative accuracy rate 99.5%.

Diabetic Retinopathy↗