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Biomedical subjects

R G Thomas

Publications and source records attributed to R G Thomas.

At least 109 records · Page 6Linked to original sources
PubMed1982

The hazardous cuffed endotracheal tube--aspiration and extubation.

A basic defect in the usage of the cuffed endotracheal tube is demonstrated. during anaesthesia a column of fluid can be supported around the tube above the inflated cuff. This fluid may represent secretions, blood or gastric contents which can be aspirated during extubation. A method of investigation was devised and possible measures to prevent postoperative chest complications are suggested.

Adult↗
PubMed1982

Intensive care unit bed extension for fluoroscopy.

Effective use of the 'C-arm' X-ray fluoroscopy machine in the intensive care unit (ICU) is often prevented by the design of the ICU bed. An inexpensive, easily constructed device is described which facilitates use of the 'C-arm' machine, yet permits the patient's monitoring and life-support apparatus to remain attached and functioning.

Beds↗
PubMed1981

Renal amoebic abscess detected on grey-scale ultrasonography. A case report.

Ultrasound scanning performed on a patient to exclude a liver abscess was negative, but demonstrated a fluid-filled lesion situated at the lower pole of the right kidney. This was confirmed on excretory urography and angiography, and aspiration produced typical amoebic pus. THe evidence for this diagnosis and the probably route of infection are discussed. The literature on renal amoebiasis is reviewed.

Abscess↗
PubMed1981

Intrahepatic foreign bodies--the ultrasound appearances.

Steel, rock and lead fragments in 3 cases were shown on static and real-time ultrasound scans to be intrahepatic in position. The materials could be differentiated from one another by their ultrasonic characteristics. The findings guided the surgical removal in 1 patient.

Adult↗
PubMed1981

Pulmonary tumours in Syrian hamsters following inhalation of 239PuO2.

Syrian hamsters were exposed to various levels of aerosolized 239PuO2 particles to attain a range of initial lung burdens (medians ranged from 40 to 144 nCi). They were allowed to live without sacrifice and had gross and microscopic tissue examinations at death. Over a range of median lung doses from 4-12 000 rad there was an average 2 per cent incidence of malignant tumours (adenocarcinomas) and 9 per cent incidence of total tumours (primarily adenomas). Some of these results are consistent with those from other laboratories using plutonium oxide aerosols but they represent considerably lower lung tumour incidences than previously observed in this laboratory using aerosols of 238PuO2-ZrO2 particles.

Animals↗
PubMed1980

Titanium retention in mice.

Intraperitoneal (i.p.) and intravenous (i.v.) injection of 44Ti in a chloride solution into mice produced no detectable translocation in body fluids. There was no obvious interorgan exchange up to 16 days after injection. The whole body biological retention half-lives had a mean of 642 days for both routes, another indication of 44Ti's insolubility in body fluids. Absorption from the gastrointestinal (g.i.) tract after administration by stomach tube was negligible. The threshold limit value (TLV) for titanium in air, based upon nuisance dust, is acceptable based upon the results of this study.

Animals↗
PubMed1979

Lung tumors from PuO2-ZrO2 aerosol particles in Syrian hamsters.

Syrian golden hamsters were given PuO2/ZrO2 particles via inhalation and/or Pu-laden ZrO2 ceramic 10-micron diameter microspheres lodged in the capillary bed of the lung. The mean initial lung burdens ranged from 8 nCi to 143 nCi for the six experimental groups of animals. Significant numbers of primary lung tumors (5-50% per group) were induced in those animals that received inhalation exposures. Additional alpha radiation administered via Pu-laden intravenous microspheres had little or no effect on tumorigenesis or the production of non-neoplastic, degenerative changes in the respiratory tract.

Aerosols↗
PubMed1979

Risk of asbestosis in crocidolite and amosite mines in South Africa.

X-rays of all while and mixed-race men employed in crocidolite and amosite mines and mills were read independently by three experienced readers according to the ILO U/C classification. Abnormality was regarded as present if reported by two or more readers. Parenchymal abnormality, defined as the presence of small irregular opacities of profusion 1/0 or greater, was found in 7.3% of the workers. Pleural thickening was found in 4.5% of the workers, costophrenic angle obliteration in 3.2%, and pleural calcification in 1.7%. The prevalences of both pleural and parenchymal abnormality were strongly related to the duration of exposure to asbestos at work. The overall prevalence of abnormality increase from 4.0% in men with exposure for 1 year or less to 47.9% in men with more than 15 years of exposure. After taking into account the effects of age and duration of asbestos exposure, the prevalence of pleural abnormality was not predicted by fiber concentration. However, white men working with amosite tended to develop a higher prevalence of pleural abnormality than did those working with crocidolite. Compared to whites, men of mixed race, who only work with crocidolite, had a high prevalence of pleural abnormality in each exposure duration category. In contrast to pleural abnormality, the prevalence of parenchymal abnormality, after taking into account the effects of age and duration of exposure, was significantly predicted by fiber concentration but not by race or asbestos type. Our results suggest that parenchymal abnormality in workers in South African asbestos mines could be largely prevented by reducing exposure to fibers visible under the light microscope. However, this may not be the case for pleural abnormality.

Adult↗
PubMed1979

Biological effects of raw and processed oil shale particles in the lungs of laboratory animals.

Environmental and occupational health concerns will have an effect on the developing oil shale technologies. The mining and crushing of large volumes of rock will be a characteristic of at least some of these technologies, and above ground disposal of proceessed shale will require adequate control measures. Exposure by inhalation to the dusts that may arise from shale oil technologies may present a hazard both in the work force and in the local population. Animal studies dealing with the effects of oil shale-related materials in the lung are in progress. Experiments involving Syrian hamsters exposed by inhalation and by intratracheal instillation are described.

Animals↗