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Biomedical subjects

D Fowler

Publications and source records attributed to D Fowler.

At least 73 records · Page 4Linked to original sources
PubMed1989

Water relations of red spruce seedlings treated with acid mist.

Pressure-volume curves, day and night transpiration rates, needle drying curves, and shoot water potentials were determined for 2-year-old red spruce trees that had been exposed for three months to a range of acid mists (pH 2.5 to pH 5.0) containing equimolar (NH(4))(2)SO(4) and HNO(3). No effect of acid mist was observed on cuticular resistance or on the rates of day and night transpiration, although trees exposed to acid mist exhibited symptoms of mild water stress. Significant decreases in maximum turgor, the relative water content (RWC) associated with zero turgor, and bulk volumetric elastic modulus occurred as the pH of the mist decreased from 5.0 to 2.5. At all RWC values, there was an increase in solute potential as mist pH decreased. Shoot water potential declined with a decrease in pH of the mist.

Journal Article↗
PubMed1989

The kidney: imaging with Tc-99m mercaptoacetyltriglycine, a technetium-labeled analog of iodohippurate.

A new renal imaging agent, technetium-99m mercaptoacetyltriglycine (MAG3, mertiatide), is currently undergoing clinical trials. Like iodine-131 orthoiodohippurate (OIH)--and unlike all other available agents--it is avidly secreted by the renal tubules. Fifty patients underwent simultaneous renal imaging studies with I-131 OIH and Tc-99m MAG3. The superior physical properties of the Tc-99m label led to better image quality in all cases, largely due to count rates that were 50-fold better. In two patients, lesions were seen with MAG3 that were not visible with OIH. The biological properties of the two agents were found to be so similar that conventional diagnostic criteria for I-131 OIH could be used for Tc-99m MAG3 with only minor modifications.

Humans↗
PubMed1988

Effects of air filtration at small SO2 and NO2 concentrations on the yield of barley.

Two cultivars of Igri and Gerbel winter barley Horteum vulgare L. were grown in open-top chambers in filtered and unfiltered air at a site with approximately 10 nl litre(-1) SO2 and 12 nl litre(-1) NO2 (seasonal mean). The experiment ran for three consecutive seasons 1982-1983, 1983-1984, 1984-1985, and significant effects of filtration were observed for each crop. In years 1982-1983 and 1984-1985, the crops in unfiltered air yielded larger grain dry matter, 9% in 1982-1983, and 8% in 1984-1985. For both crops, the differences were statistically significant at the 5% level. Differences were also observed for the remaining above-ground dry matter, and these were consistent in direction in each year but statistically significant only in 1984-1985. In both growing seasons (1982-1983 and 1984-1985), there were no major pest infestations and no long-term water stress or photochemical ozone episodes. In the remaining experiment (1983-1984) similar air concentrations of SO2 and NO2 produced effects of the opposite sign to those observed in 1982-1983 and 1984-1985. Significant reductions in grain yield (13%) were obtained in unfiltered air. The only major environmental difference for the 1983-1984 crop was a notable dry period in May and June 1984 with marked water stress in the crop, requiring irrigation. These results suggest that the relationship between yield and pollutant concentration may be confounded by additional stresses, many of which are a common component of the growing season for major crops.

Journal Article↗
PubMed1988

Coxsackie virus-induced acute pancreatitis in a long-term dialysis patient.

This report describes a patient on continuous ambulatory peritoneal dialysis (CAPD) who developed acute pancreatitis with pseudocyst formation and cloudy dialysate with pleocytosis in the absence of bacterial or fungal organisms. To our knowledge, pancreatitis, in the absence of hypertriglyceridemia in a CAPD patient, has not been previously reported. There was a significant increase in Coxsackie B1 and B6 viral titers by complement fixation test, suggesting Coxsackie virus-induced pancreatitis.

Acute Disease↗
PubMed1986

Modified microstomia prevention splint.

The modified microstomia prevention splint (MMPS) was designed to overcome burn microstomia which could not be treated by the use of conventional microstomia prevention appliances. In addition, further modifications eliminated problems of pressure on the oral mucosa. The MMPS is now the preferred splint at the Royal Brisbane Hospital Burns Unit.

Burns↗
PubMed1986

Glucocorticoid receptors in Epstein-Barr virus-transformed lymphocytes from patients with glucocorticoid resistance and a glucocorticoid-resistant New World primate species.

Members of a previously reported family with glucocorticoid resistance and several New World primates have high plasma cortisol concentrations without any signs of glucocorticoid excess. The glucocorticoid receptor in circulating leukocytes and cultured skin fibroblasts from these patients and the animals is characterized by a decreased affinity for dexamethasone. On the other hand, the cell content of receptor is similar to that of corresponding tissues of normal humans. Detailed biochemical-biophysical studies of the glucocorticoid receptor in this familial syndrome and animal model became possible with the use of Epstein-Barr virus-transformed lymphocyte lines. Cell lines from patients with this syndrome and from the marmoset (Saguinus oedipus) contained decreased amounts of glucocorticoid receptors with concomitant decreases in nuclear receptor content compared to cultured Epstein-Barr virus-transformed lymphocytes from normal human subjects. This may reflect diminished induction of glucocorticoid receptor during viral transformation of cells from the patients and the animal model. Receptors from a severely affected glucocorticoid-resistant patient and the marmoset had decreased affinity for dexamethasone. Evidence for a mild affinity defect of the glucocorticoid receptor in a patient with asymptomatic glucocorticoid resistance was obtained by increased hormone-receptor dissociation at an elevated temperature. Thermal stability, mero-receptor formation, thermal activation of cytosolic receptor, and mol wt of receptors from all cell lines were normal. Only the receptors of the severely affected patient had a discernible defect in temperature-induced activation of intact cells. We conclude that the major detectable change in the receptor in both the patients and the animal model is the decreased affinity for glucocorticoid. Viral receptor induction is decreased in both patient and marmoset cells. The physiological relevance of this phenomenon is not known. Gross receptor molecule changes or changes in its stability at higher temperatures were not found. Mixing studies did not show involvement of cytosolic modifiers or inhibitors. Mutation(s) of the receptor molecule leading to low affinity for the hormone is the most likely explanation of the isolated glucocorticoid resistance in the patients. The glucocorticoid resistance of the New World primate, which is part of generalized steroid hormone resistance, appears to be a result of more complex changes.

Animals↗
PubMed1984

Results of early excision and grafting in hand burns.

A total of 658 admissions to the Burns Unit at the Royal Brisbane Hospital were reviewed over a 4-year period. During this time, 73 hand burns were treated. The policies of the Burns Unit regarding hand burns are detailed; and, where possible, early excision and grafting is performed. The results of these hand burns are discussed and indicate minimal requirements for reconstructive surgery. The most common reconstructive surgery needed was for web space release in 10 patients and excision of hypertrophic scar in 2 patients. It is concluded that early excision and grafting of hand burns is safe and practical, and combined with adequate splinting, exercise and pressure garments, gives good results and lessens hospital stay in patients with relatively small injuries. The duration of stay in hospital in patients with large burns is not due to the treatment of their hand burns, but to their overall large body surface area burnt.

Adolescent↗
PubMed1984

The effects of interruption on squirrel monkey temporary threshold shift to a 96-hour noise exposure.

6 squirrel monkeys (Saimiri scuireus ) were exposed to an octave band of noise with a center frequency of 500 Hz under both continuous and interrupted conditions. Continuous exposures lasted for 4, 8, 16, 24, 48, 72 and 96 h, with complete recovery of hearing before the next exposure. The interrupted exposure was 96 h, long with 5-min interruptions so that temporary threshold shift (TTS) could be measured at 2, 4, 8, 12, 16, 24, 36, 48, 60, 72 and 84 h of exposure. There were no differences in TTS from 8 to 96 h of exposure between the two conditions. However, at 4 h of exposure, the interrupted exposure showed significantly less TTS (p less than 0.05) than the continuous exposure. The only difference between the exposures was a 5-min interruption at 2 h of exposure during the interrupted exposure. Thus, the interrupted-exposure method is valid for making generalizations about continuous exposures of 8 h or longer. The results also confirmed our previous finding that there was no asymptotic threshold shift for the squirrel monkey although we extended the exposure time to 96 h in this experiment. The similarity of human and squirrel monkey TTS growth functions is consistent with our earlier results and supports the suitability of the squirrel monkey as an animal model for noise-induced hearing loss in humans.

Animals↗
PubMed1982

The squirrel monkey: receptor-mediated end-organ resistance to progesterone?

Fertile females of a New World primate species, the squirrel monkey (Saimiri sciureus), have plasma progesterone concentrations that vary between 57 and 510 ng/ml during the reproductive cycle and are 10- to 20-fold higher than those seen in cynomolgus monkeys (Macaca fascicularis) and other Old World primates, including man. The plasma progesterone level during pregnancy is high and varies between 140 and 490 ng/ml. Estradiol levels during the reproductive cycle and pregnancy are also higher than those of cynomolgus monkeys. After 2-day treatment of ovariectomized monkeys with estradiol in oil, the progesterone receptor content in the uterine cytosol of the squirrel monkey is one eighth that in similarly treated cynomolgus monkeys [60.4 +/- 6.5 fmol R5020 bound/mg protein vs. 496 +/- 55 (mean +/- SE); n = 8]. The receptor affinity for R5020 is the same in both species. Thus, the elevated plasma progesterone levels in squirrel monkeys appear to be a compensatory response to a receptor-mediated decrease in sensitivity to progesterone. The squirrel monkey may be a model for the study of the mechanism of action and regulation of secretion of progesterone.

Animals↗