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Biomedical subjects

G Thompson

Publications and source records attributed to G Thompson.

At least 19 recordsLinked to original sources
PubMed1992

Phase I/II study of intraperitoneal iproplatin in patients with minimal residual disease following platinum-based systemic therapy for epithelial ovarian carcinoma.

13 patients with minimal residual disease following platinum-based systemic therapy for epithelial ovarian cancer were treated with intraperitoneal iproplatin. A total of three cycles were given at monthly intervals. All patients had minimal residual disease (defined as less than 2 cm in diameter) or positive cytology documented at second look laparotomy following systemic chemotherapy. Iproplatin was administered via a temporary dialysis catheter (n = 11) or a semi permanent Tenckhoff peritoneal dialysis catheter (n = 2). The dose of iproplatin ranged from 150 to 450 mg/m2. No responses to therapy were documented. In this trial the major toxic side effects of iproplatin were thrombocytopenia, diarrhoea, nausea and vomiting. The maximum tolerated dose was 300 mg/m2.

Adult↗
PubMed1992

Auditory responsiveness of premature infants utilizing visual reinforcement audiometry (VRA).

The purpose of this investigation was to study the relationship between visual reinforcement audiometry (VRA) performance and age (i.e., corrected and mental) with 60 premature infants. VRA performance was classified as unacceptable, marginal, or acceptable based on conditionability and number of responses obtained before habituation to the task. The results indicated that mental age and corrected age were significantly related to VRA performance. It was found that a corrected age of 8 mo and/or a mental age of 6 mo is typically required for acceptable performance using VRA. A lack of responsiveness to the VRA procedure at these ages would most likely be due to hearing loss as opposed to a general developmental delay. The data from this study would not support a large scale behavioral hearing screening program for premature infants below 8 mo corrected age or 6 mo mental age.

Acoustic Stimulation↗
PubMed1992

Strategies for increasing response behavior of 1- and 2-year-old children during visual reinforcement audiometry (VRA).

This study investigated strategies for increasing the number of responses that can be obtained from young children during visual reinforcement audiometry. Subjects included normal 1- and 2-yr-old children. Responses before habituation were studied as a function of age, reinforcer conditions, and test sessions. It was found that: (1) using two reinforcers led to more responses before habituation than use of a single reinforcer; (2) after habituation in test session 1 and a 10-min break, most 1-yr-olds demonstrated a minimum of five additional responses in test session 2; and (3) 2-yr-olds habituated more rapidly than 1-yr-olds.

Acoustic Impedance Tests↗
PubMed1992

Gingival crevicular fluid concentration and side effects of minocycline: a comparison of two dose regimens.

The purpose of this study was to conduct a direct comparison of two dose regimens of minocycline to determine 1) whether they achieved crevicular fluid concentrations in a therapeutic range; and 2) the frequency of side effects. In a double-blind design, 30 patients divided into 2 groups were given either 100 mg minocycline or 200 mg minocycline per day for an 8-day period. The concentration of minocycline in the gingival clevicular fluid (GCF) at 8 days was 4.77 micrograms/ml for the 100 mg a day group and 5.97 micrograms/ml for the 200 mg a day group and at 15 days was 4.30 micrograms/ml for the 100 mg a day group and 4.17 micrograms/ml for the 200 mg a day group. There was no significant difference in the antibiotic concentration in the gingival crevicular fluid between the 2 groups. Reported adverse experiences to the minocycline were greater in the 200 mg a day group. Short-term changes in periodontal health as measured by plaque index, gingival index, pocket depth, and bleeding upon probing showed improvements in all parameters over the 15 day period. There were no significant differences in these parameters between the 100 mg a day and 200 mg a day group. At 8 days reduced levels of Porphyromonas gingivalis and Prevotella intermedia were achieved but they were not eliminated from infected subgingival sites in either group. Achieving bacteriostatic concentrations of GCF, fewer side effects, and the potential for better compliance suggests that a single daily dose of 100 mg minocycline should now be investigated for its efficacy in managing periodontal infections manifesting as periodontitis.

Adult↗
PubMed1991

Early identification of hearing loss: listen to parents.

Families of 49 hearing-impaired children responded to a questionnaire requesting information about the identification of their child's hearing loss. Parents were the first to suspect the hearing loss in 48 cases but more often than not were told that the child would outgrow it or was too young to test. When professionals agreed with the parents and attended to their concerns, confirmation of the hearing loss occurred significantly more rapidly than when they disagreed with parents and ignored their concerns. A child whose hearing loss is not clearly identified and whose communication is inadequate or nonexistent, causes frustration and stress within the family and prevents the child from receiving the maximum benefit from early language input and amplification. It would benefit both the child and family if professionals would listen to parental concerns regarding their child and assist in the early identification process.

Child, Preschool↗
PubMed1990

Assessment of observer variation in measuring the Radiographic Vertebral Index in patients with multiple myeloma.

The Radiographic Vertebral Index (RVI) was assessed as a possible outcome measure for bone disease in myeloma by evaluating within and between reader reproducibility. Four readers (2 radiologists and 2 clinical hematologists) independently scored, on two separate occasions, the RVI on 40 radiographs from patients with myeloma. Each vertebra from third thoracic (T3) to fifth lumbar (L5) received a score of "1" if normal, "2" if biconcave and "4" if crushed or fractured. RVI global scores, therefore, could vary from a minimum of 15, for no damage, to a potential maximum of 60 in which all vertebrae are collapsed. Agreement was determined for each vertebra using crude percentage agreement and the kappa statistic (which corrects for chance-expected agreement) for categorical data, and for global score using analysis of variance and calculating intra-class correlation. With increasing mean abnormality score on individual vertebrae there was a corresponding increase in kappa and reduction in crude percentage agreement. Within readers, the mean percentage agreement across all vertebrae varied from 85.6 to 90.3% and the observed differences just reach statistical significance (p = 0.048). Mean kappa values ranged from 0.48 to 0.63 and were similar across readers. Differences in intra-reader agreement were not related to subspecialty. When between reader percentage agreement and kappa scores were assessed for radiologists and non-radiologist clinicians, no difference could be detected. Agreement with respect to intra-reader mean global RVI scores was excellent as illustrated by the intra-class correlation coefficient which varied from 0.89 to 0.94. The mean intra-class correlation for radiologists was 0.92, compared with 0.91 for non-radiologists.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1990

The onset of mammary secretion of medium-chain-length triglyceride fatty acids in the cow milked pre-partum.

Six Friesian cows were milked daily, and arterial and mammary venous blood samples were taken between day 266 of gestation and day 6 after parturition. Samples of blood plasma were analysed for their content of acetate and progesterone, and mammary secretion for potassium, isocitrate, 2-oxoglutarate and triglyceride fatty acids. The onset of secretion of medium-chain triglyceride fatty acids was preceded by, or coincided with, increases of potassium and isocitrate concentration in the secretion. The onset of fatty acid secretion was not accompanied by any change in the gland's extraction of acetate from the circulation, and did not occur at a consistent time relative to parturition or changes in plasma progesterone concentration.

Acetates↗
PubMed1990

Contraction stress fetal heart rate monitoring at preterm gestational ages.

The evaluation of fetal well-being by fetal heart rate monitoring at preterm gestational ages remains a difficult and important area for investigation. While the nonstress test has achieved widespread usage, a role for the contraction stress test remains uncertain. This study describes the outcome of 113 contraction stress tests which were performed for persistent fetal heart rate nonreactivity in 78 pregnancies of less than 37 completed weeks' gestation. There were no fetal deaths and no obstetric complications which could be attributed to these tests. The finding of a negative contraction stress test provided reassurance which facilitated significant prolongation of pregnancy. Contraction stress test appear to be a safe and effective method of investigating further the clinical dilemma of persistent fetal heart rate nonreactivity in high risk pregnancies at preterm gestational ages.

Female↗
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↗