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Biomedical subjects

T M Little

Publications and source records attributed to T M Little.

15 recordsLinked to original sources

Dibutyryl cAMP effects on thromboxane and leukotriene production in decompression-induced lung injury.

Decompression-induced venous bubble formation has been linked to increased neutrophil counts, endothelial cell injury, release of vasoactive eicosanoids, and increased vascular membrane permeability. These actions may account for inflammatory responses and edema formation. Increasing the intracellular cAMP has been shown to decrease eicosanoid production and edema formation in various models of lung injury. Reduction of decompression-induced inflammatory responses was evaluated in decompressed rats pretreated with saline (controls) or dibutyryl cAMP (DBcAMP, an analog of cAMP). After pretreatment, rats were exposed to either 616 kPa for 120 min or 683 kPa for 60 min. The observed increases in extravascular lung water ratios (pulmonary edema), bronchoalveolar lavage, and pleural protein in the saline control group (683 kPa) were not evident with DBcAMP treatment. DBcAMP pretreatment effects were also seen with the white blood cell counts and the percent of neutrophils in the bronchoalveolar lavage. Urinary levels of thromboxane B2, 11-dehydrothromboxane B2, and leukotriene E4 were significantly increased with the 683 kPa saline control decompression exposure. DBcAMP reduced the decompression-induced leukotriene E4 production in the urine. Plasma levels of thromboxane B2, 11-dehydrothromboxane B2, and leukotriene E4 were increased with the 683-kPa exposure groups. DBcAMP treatment did not affect these changes. The 11-dehydrothromboxane B2 and leukotriene E4 levels in the bronchoalveolar lavage were increased with the 683 kPa exposure and were reduced with the DBcAMP treatment. Our results indicate that DBcAMP has the capability to reduce eicosanoid production and limit membrane permeability and subsequent edema formation in rats experiencing decompression sickness.

Animals↗

Cardiovascular deconditioning and venous air embolism in simulated microgravity in the rat.

BACKGROUND: Astronauts conducting extravehicular activities undergo decompression to a lower ambient pressure, potentially resulting in gas bubble formation within the tissues and venous circulation. Additionally, exposure to microgravity produces fluid shifts within the body leading to cardiovascular deconditioning. A lower incidence of decompression illness in actual spaceflight compared with that in ground-based altitude chamber flights suggests that there is a possible interaction between microgravity exposure and decompression illness. HYPOTHESIS: The purpose of this study was to evaluate the cardiovascular and pulmonary effects of simulated hypobaric decompression stress using a tail suspension (head-down tilt) model of microgravity to produce the fluid shifts associated with weightlessness in conscious, chronically instrumented rats. METHODS: Venous bubble formation resulting from altitude decompression illness was simulated by a 3-h intravenous air infusion. Cardiovascular deconditioning was simulated by 96 h of head-down tilt. Heart rate, mean arterial blood pressure, central venous pressure, left ventricular wall thickening and cardiac output were continuously recorded. Lung studies were performed to evaluate edema formation and compliance measurement. Blood and pleural fluid were examined for changes in white cell counts and protein concentration. RESULTS: Our data demonstrated that in tail-suspended rats subjected to venous air infusions, there was a reduction in pulmonary edema formation and less of a decrease in cardiac output than occurred following venous air infusion alone. Mean arterial blood pressure and myocardial wall thickening fractions were unchanged with either tail-suspension or venous air infusion. Heart rate decreased in both conditions while systemic vascular resistance increased. CONCLUSIONS: These differences may be due in part to a change or redistribution of pulmonary blood flow or to a diminished cellular response to the microvascular insult of the venous air embolization.

Animals↗

Conductive education at the Petö Institute, Budapest.

Conductive education, which was developed at the Petö Institute in Budapest, has been publicised incorrectly as a method of treatment for children with cerebral palsy. From the results of information given and our own observations during a week's visit to the institute we conclude that a minority of carefully selected children with cerebral palsy and spina bifida, who have a relatively good prognosis, are educated at the institute; the education is carried out with appropriate medical, surgical, and orthotic intervention; and the children probably function better as a result of the intensive programme than do similar children in Britain in areas where therapy is scarce. They seem to achieve, however, what we would expect similar children in Britain to do when facilities are adequate. Though our findings do not therefore justify using public funds to refer children to the institute, some (self selected) families benefit from a visit, particularly from the positive attitudes of the staff. The role of the conductor and the integration of programmes into a classroom setting have much to recommend them, and conductive education, if successfully transferred to Britain, might be beneficial to a wider range of children than in Hungary.

Activities of Daily Living↗

Torsion of the testis: why is the prognosis so poor?

The cases of 83 boys who were admitted to hospital with acute testicular pain or swelling were studied. Twenty seven had torsion of the testis, and 15 (55%) of these lost a testis. The main reason for the poor results was delay by the patient or his parents in seeking medical attention.

Adolescent↗

Has treatment for childhood gastroenteritis changed?

Because so many children with gastroenteritis in our area were being treated with drugs, which are potentially harmful, we assessed the extent of treatment before admission to hospital of 288 children. Sixty four had been treated: 45 with antibiotic, antidiarrhoeal, or antiemetic drugs and 34 had been given glucose-electrolyte solution, 15 of those had also been given drugs; 119 had had no treatment. Since 1979 there has been a decrease in the use of drugs for gastroenteritis, but glucose-electrolyte mixtures are still underused.

Anti-Bacterial Agents↗

Diphenylhydantoin-induced gingival hyperplasia: its response to changes in drug dosage.

Changes in gingival hyperplasia were studied in 48 patients treated for epilepsy with diphenylhydantoin (DPH) over a two-year period. During this time changes in the dose of DPH were made in some patients in order to increase control of seizures or decrease side-effects: in 27 patients the dose was increased, in nine it was decreased and in 12 the dose remained unchanged. It was found that the severity of gingival hyperplasia varied directly with both the dose and serum level of the drug.

Adolescent↗