Search PubMed⌕ Search

Biomedical subjects

R H Gray

Publications and source records attributed to R H Gray.

At least 163 records · Page 9Linked to original sources
PubMed1984

Deposition and retention of inhaled aggregate 67Ga2O3 particles in beagle dogs, Fischer-344 rats, and CD-1 mice.

Deposition and retention of inhaled 67Ga2O3 aerosols were measured in ten beagle dogs to provide reasonable estimates for human deposition and in Fischer-344 rats and CD-1 mice to estimate lung burdens in small animals frequently used in toxicological evaluations. Aggregated particles of 67Ga2O3, 0.1 micron mass median diameter (MMD), were produced using heat treatment of 67Ga tetramethylheptanedione. Whole-body counting and gamma camera imaging were used to measure deposition. Pulmonary deposition in dogs was measured as 25% of the inhaled particles for the 0.1 micron particles. Tracheobronchial and nasopharyngeal deposition were much lower, 7% and 7% respectively. Pulmonary deposition of 0.1 micron (MMD) particles was calculated as 10% and 11% of inhaled particles in Fischer-344 rats and 15 and 20% in mice for two separate nose-only exposures of each species.

Aerosols↗
PubMed1983

Convergent results of two methods of estimating the prevalence of problem drinking.

Two studies were conducted using different methods of estimating the prevalence of problem drinking among the Canadian Armed Forces. In one case, data on alcohol sales from base outlets were used to calculate mean per capita consumption, which in turn was applied to a theoretical and, to some extent, empirically-validated plot of the distribution of consumption often referred to as the Ledermann curve. Criteria for different levels of problem drinking were then applied to this distribution. In the other case, estimates of problem drinking and presumptive problem drinking were derived from self-reported data on the correlates and sequelae of excessive drinking. The results derived from the two methods were highly convergent. As in the case of studies from the United States, the estimates were disturbingly high, both placing approximately 18% of the respective populations in he hazardous drinking category. The preventive and treatment-related implications of these findings are discussed.

Alcohol Drinking↗
PubMed1982

Microcomputer system in an accident unit.

A microcomputer-based records system has been developed for use in the accident unit of a district general hospital. Patient details are entered directly at the reception desk and the computer generates a casualty card that is updated after the patient has been seen by the doctor, who determines the diagnosis to be recorded and specifies the injury coding. Information is stored on floppy discs, each holding the details of 3400 patients. The computer is used to produce a daily log-book of attendances, including revisits. The stored data may be examined and analysed for both administrative and medical purposes. The work load can be rapidly analysed according to various options that include the nature, type, and site of injuries. The system was introduced in December 1980. Location within the unit allows control over its operation, and many of the limitations of a manual system have been overcome.

Computers↗
PubMed1981

Vaginal bleeding disturbances associated with the discontinuation of long-acting injectable contraceptives. From the World Health Organization Special Programme for Research, Development, and Research Training in Human Reproduction; Task Force on Long-acting Systemic Agents for the Regulation of Fertility.

A randomized comparative trial of 832 women receiving norethisterone oenanthate (NET-OEN) and 846 women receiving depot medroxyprogesterone acetate (DMPA) injections at 12 week intervals was conducted in 10 centers. The pregnancy rate with NET-OEN was significantly higher than with DMPA. The termination rate for amenorrhoea was substantially lowe with NET-OEN than DMPA, whereas the discontinuation rates for bleeding problems were similar with the two drugs. Analysis of bleeding patterns among continuing and discontinuing users suggests that women tolerated frequent bleeding episodes, but found prolonged bleeding or prolonged bleeding-free intervals unacceptable. Bleeding for more than 30 days during an injection interval and complete amenorrhoea for a whole injection interval were jointly associated with 43.7% of all terminations among NET-OEN users and 64.5% of all terminations among DMPA users. In future efforts to improve the acceptability of long-acting injectable contraceptives, more attention should be given to the control of prolonged amenorrhoea and prolonged bleeding.

Amenorrhea↗
PubMed1981

The return of fertility following discontinuation of oral contraceptives in Thailand.

The return of fertility following discontinuation of oral contraception was studied in a survey of 437 Thai women who stopped taking the pill to have a planned pregnancy. Conception rates were reduced during the first 2 months after stopping the pill, and the median delay prior to conception was approximately 3 months. This delay was shorter for nulligravid women. Most women (94.3%) became pregnant within 2 years of stopping the pill. There was a cyclic pattern in the monthly pregnancy rates with peak rates around 3 and 6 months after discontinuing contraception. These findings are similar to those reported for Caucasian women.

Adult↗
PubMed1980

Post-partum tubal ligation by nurse-midwives and doctors in Thailand.

A shortage of doctors limits the provision of post-partum sterilisation services in rural areas of Thailand. To overcome this problem nurse-midwives with theatre experience were trained to perform post-partum tubal ligation by a mini-laparotomy incision under local anaesthesia. The performance of the nurse-midwives was compared with that of doctors in a controlled, randomised clinical trial. Some operative difficulty was encountered by the nurses in 4.9% of cases and by the doctors in 2.0% of cases. This difference is not statistically significant and arose largely because the nurse-midwife cases were more obese. Nurse-midwives required a significantly longer operating-time (18.5 min) than doctors (11.9 min). However, postoperative morbidity was similar in the two groups (7.0% and 6.0%, respectively). These results suggest that trained nurse-midwives with theatre experience can safely provide post-partum sterilisation services. A further field trial is underway.

Clinical Trials as Topic↗
PubMed1980

Return of fertility after discontinuation of depot medroxyprogesterone acetate and intra-uterine devices in Northern Thailand.

796 Thai women who stopped using the long-acting injectable contraceptive 'Depo-Provera' (medroxyprogesterone acetate) and 125 women who had an intra-uterine device removed to have a planned pregnancy were followed-up to ascertain the delay between conception and the end of contraception, and to determine the proportion of women who did not conceive in the 2 years after discontinuation. The median delay before conception was 5.5 months plus the estimated duration of the effect of the last injection of depo-provera and 4.5 months after discontinuing the IUD. Since depo-provera acts for approximately 15 weeks, women can except a median delay to conception of around 9 months after their last injection. The proportions of women who did not conceive within 1 year and within 2 years of stopping contraception by the two methods were similar. There was no evidence to suggest that prolonged use of depo-provera increases the delay before conception, and the return of fertility among never pregnant ex-users resembled that of ever pregnant ex-users.

Delayed-Action Preparations↗
PubMed1980

Effect of microtubule-disrupting drugs on protein and RNA synthesis in Physarum polycephalum amoebae.

The effects of the microtubule-disrupting drugs, colchicine, vinblastine, podophyllotoxin, griseofulvin, and lumicolchicine (10(-5) M), on protein and RNA synthesis were studied in Physarum polycephalum amoebae in culture. All, except lumicolchicine, were found to simultaneously reduce the rate of protein synthesis and stimulate RNA synthesis. These results parallel the effects seen in cells exposed to heat shock. Treatment of cells with a microfilament-disrupting drug, cytochalasin B (10 micrograms/ml in ethanol), resulted in a reduced rate of protein synthesis after 2 h compared to a similar effect by vinblastine in 5--15 min. A morphological abnormality, microtubule paracrystals, were seen associated with centrioles in vinblastine-treated cells in which protein synthesis had been reduced by 50%. Vinblastine and podophyllotoxin were shown to interfere with the recovery of protein synthesis after inhibition by low or elevated temperatures. The possible role of microtubules in regulating the translational response of a cell to an external environmental stimulus is discussed.

Centrioles↗