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Biomedical subjects

G B Thomas

Publications and source records attributed to G B Thomas.

83 records · Page 5Linked to original sources
PubMed1981

Some non-auditory correlates of the hearing threshold levels of an aviation noise-exposed population.

In a retrospective analysis of data collected during the 1963 followup of the NAMRL Thousand Aviator Study, two hearing level groups were identified, normal and impaired, and compared along 33 non-auditory dimensions. It was discovered that these two equally noise-exposed groups could be differentiated according to their smoking history and eye color. That is, the impaired hearing group reported smoking more cigarettes for a greater period of time than did the members of the normal hearing group. Furthermore, blue-eye individuals were over-represented in the impaired hearing group and under-represented in the normal hearing group, whereas the reverse was true for brown-eyed aviators. This latter finding is consistent with reports linking temporary hearing loss and eye color. There was 31 other physical, psychological, and sociological measures which failed to appear differentially in the two groups.

Adult↗
PubMedDate not supplied

Relative variability in bioavailability of oral controlled-release formulations of oxycodone and morphine.

A retrospective analysis compared the coefficients of variation associated with the maximum plasma concentration (Cmax) and the extent of absorption (area under the curve [AUC] from 0 hour to the last observation) for oral, controlled-release tablet formulations of oxycodone (OxyContin) and morphine (MS Contin). Data from fasting, male subjects aged 18 to 45 years were taken from five controlled-release oxycodone (N = 82) and seven controlled-release morphine (N = 101) single-dose, bioequivalence studies. The coefficients of variation of Cmax and AUC were approximately 33% less for controlled-release oxycodone than for controlled-release morphine (P =.005). The variation from the minimum to maximum value was two to three times less for controlled-release oxycodone than for controlled-release morphine. Among healthy male subjects, the absorption of oxycodone from oral controlled-release oxycodone was significantly more consistent than the absorption of morphine from oral controlled-release morphine in terms of both maximum absorption and extent of absorption.

Adolescent↗
PubMedDate not supplied

Steady-state pharmacokinetics of controlled release oral morphine sulphate in healthy subjects.

The pharmacokinetics of oral morphine sulphate as controlled release tablets ('MS-Contin') and solution were compared at steady-state. Plasma morphine concentrations were determined over 24 hours following the last dose of each drug when given in a randomised, crossover fashion to healthy subjects. Radioimmunoassay was used, which was sensitive yet provided good specificity relative to high-performance liquid chromatography. Controlled release tablets had 86% the bioavailability of the solution. Although each dose of controlled release tablets was double that of the solution, their peak plasma concentrations were the same. Time to maximum concentration was 3 times longer for controlled release tablets with an absorption half-life twice that of the solution. Elimination of both drugs was similar and biphasic with the minor terminal portion at 10 times the half-life of the major early process. These data explain the analgesic duration of 12 hours observed in clinical studies and the lack of accumulation with morphine compared with methadone.

Adult↗
PubMedDate not supplied

Relationship between two serotypes of avian mycoplasmas by serological and DNA-DNA hybridization tests.

Genetic relatedness among eight strains of avian mycoplasmas representing two serotypes, C-O and D-P, was determined using DNA-DNA hybridization tests. One strain from each serotype was found to be misclassified. The average percent homology between the two serotypes was 34.1% at 56 C and 18.6% at 66 C. The average homology among the four C-O organisms was 99.6% at 56 C and 93.5% at 66 C, while among the four D-P strains the average homology was 91.6% at 56 C and 92.2% at 66 C. These relationships correlated with antigenic cross-reactions observed in complement fixation (CF) and fluorescent antibody (FA) tests. Thermal denaturation of the pure DNA from each strain resulted in base compositions of 25.0 to 28.2 moles percent guanosine plus cytosine (GC). Thermal denaturation of selected hybrid DNA revealed a linear relationship between percent homology and delta melting temperature (1 C delta Tm for 15% difference in percent homology). Thirty-four percent homology between the organisms of C-O and D-P serotypes indicates a minor antigenic relationship; thus, it is recommended that these two serotypes be retained as separate groups.

Complement Fixation Tests↗