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Biomedical subjects

D Chandler

Publications and source records attributed to D Chandler.

At least 91 records · Page 5Linked to original sources
PubMed1983

Persistent corneal edema in the congenital rubella syndrome.

Corneal edema occurring in the congenital rubella syndrome can result from coexistent glaucoma or develop in the absence of an elevated intraocular pressure. We examined a 36-week-old female infant with documented congenital rubella syndrome who had bilateral corneal stromal edema without attendant congenital glaucoma. Histopathologic examination of the cornea revealed absent Descemet's membrane, deep interstitial keratitis, stromal corneal swelling, and deranged, focally absent endothelial cells. A viral infiltration of endothelium is postulated as the mechanism of the corneal edema and keratitis.

Cataract↗
PubMed1983

FMLP-induced enzyme release from neutrophils: a role for intracellular calcium.

The ability of the chemotactic peptide N-formylmethionyl-leucyl-phenylalanine (FMLP) to stimulate beta-glucuronidase release and 45Ca2+ release from rabbit neutrophils was studied. FMLP stimulated enzyme release from cytochalasin B-treated cells either in the presence or the absence of extracellular calcium. Depletion of cell calcium, by exposure to either ethyleneglycol-bis(beta-aminoethylether)-N,N'-tetraacetic acid or the calcium ionophore A23187, blocked the ability of FMLP to stimulate enzyme release and 45Ca2+ release in the absence of extracellular calcium. The ability of A23187 to lower the 45Ca2+ content of neutrophils, to block FMLP-stimulated 45Ca2+ release, and to inhibit FMLP-stimulated enzyme release in the absence of calcium was dose dependent over the same concentration range (10(-8) to 10(-6) M A23187) for all three actions. In contrast, FMLP stimulated enzyme release from A23187-treated cells, provided that extracellular calcium was present. This secretory response was normal as judged by cell ultrastructure and FMLP dose-response relationships. It is concluded that A23187 depletes a pool of intracellular calcium usually released by FMLP and that release of calcium from this pool is necessary for initiation of enzyme secretion in the absence of extracellular calcium.

Animals↗
PubMed1983

The clinical manifestation and pathogenesis of enteritis associated with rotavirus and enterotoxigenic Escherichia coli infections in domestic animals.

Rotavirus and enterotoxigenic Escherichia coli (ETEC) are enteropathogens each capable of inducing diarrhoea in some animal species and man. Unstressed young animals develop an age-related resistance to infection with either rotavirus or ETEC which differs for each animal species. The effects of experimental infection of calves, lambs, foals and piglets with rotavirus and ETEC given either alone or in combination, have been examined. In general, dual infections tended to lengthen the period of age susceptibility and increase the severity of gastroenteritis, compared to infection with either agent alone. ETEC caused little or no pathological changes in the small intestine while rotavirus induced moderate inflammatory, morphological and physiological changes including reduced activity of membrane-bound digestive enzymes. In dual infections, mucosal lesions were more severe than those seen after rotavirus infection and ETEC proliferation in the lumen of the small intestine was greater than in animals infected with ETEC alone. Two distinct mechanisms of diarrhoea, presumably, were involved; net fluid hypersecretion into the lumen of the gut mediated by ETEC enterotoxin(s), and brush border maldigestion and malabsorption which was caused by rotavirus infection of the small intestine.

Animals↗
PubMed1982

The clearance of intravitreal triamcinolone acetonide.

Since high corticosteroid levels are important in achieving inhibition of intraocular cellular proliferation, we studied the clearance of an intravitreally injected slowly dissolving corticosteroid in the rabbit eye. Triamcinolone acetonide (0.5 mg) disappeared rapidly in eyes that underwent a combined vitrectomy and lensectomy (average, 6.5 days) and more slowly in eyes that underwent vitrectomy only (average, 16.8 days) compared with unoperated normal rabbit eyes (average, 41 days). The ophthalmoscopic disappearance of the white crystals correlated well with a sensitive colorimetric test for clearance of the corticosteroid. Direct observation is therefore an accurate method of assessing the absorption of the corticosteroid. If used therapeutically, this study suggests that more frequent injections of triamcinolone acetonide would be necessary in eyes that underwent vitrectomy, compared with normal eyes.

Animals↗
PubMed1982

A transmission and scanning electron microscopic study of surgically excised preretinal membrane proliferations in diabetes mellitus.

Thirty preretinal membranes excised from diabetic patients during pars plana vitrectomy were examined by transmission electron microscopy, scanning electron microscopy, or both. All the specimens were still correctly orientated after removal from the eyes. All the specimens contained collagen in varying amounts and most had blood vessels with a thickened basal lamina and adjacent pericytes. Fenestrated capillaries were identified in only four of the 21 membranes containing blood vessels. A wide variety of cell types were scattered within the membranes, including polymorphonuclear leukocytes, lymphocytes, plasma cells, macrophages (containing melanin and hemosiderin), glial cells, retinal pigment epithelium, and cells of uncertain derivation. Scanning electron microscopy showed the retinal side of the membranes to be smoother than the vitreal side and disclosed preretinal cells on the vitreal side of the membranes, either as individual stellate cells or as a monolayer of flattened cells with microvilli. Membranes stripped from the surface of the retina had a smooth, generally acellular surface on the retinal side.

Diabetic Retinopathy↗
PubMed1982

Experimental colibacillosis in gnotobiotic piglets exposed to 3 enterotoxigenic serotypes.

Three strains of enterotoxigenic Escherichia coli (ETEC) (064:KSNT, K88ac; 020:KSNT, K88ac and 08:K85ab, K99) originally cultured from outbreaks of diarrhoea in piglets a few hours old, were administered orally to gnotobiotic piglets. There was a marked age-related difference in the clinical response to infection between the 3 strains although they all produced heat-stable toxin. All 3 strains produced severe clinical signs of depression, anorexia, vomiting, diarrhoea, followed by dehydration and death in one-day-old piglets. In piglets infected at 3 days of age the two K88+ ETEC caused diarrhoea and death but the K99+ ETEC induced moderate diarrhoea only. In piglets infected at 7 days of age, the 064 strain produced severe diarrhoea and death, and 020 strain caused mild diarrhoea in 3 of 6 piglets with one death while the 08 strain caused no illness. Pathological changes in the intestinal tract associated with these infections were minimal, or absent. Immunofluorescent staining with homologous hyperimmune sera demonstrated adherence of the 3 ETEC strains to the brush border of small intestinal epithelial cells. Fluorescing organisms were observed in all infected piglets irrespective of the severity of clinical signs but the degree and extent of colonisation varied with the age of the piglets and the infecting strain. This may explain the difference in clinical response between the 3 strains.

Animals↗
PubMed1981

The lack of toxicity of intravitreally administered triamcinolone acetonide.

We gave one eye of each 21 rabbits an intravitreal injection of 1 mg of triamcinolone acetonide; the other eye received an injection of an equal volume of saline solution as a control. Results of slit-lamp examinations, ophthalmoscopy, intraocular pressure, electroretinography, and light electron microscopy all remained normal throughout the three-month course of the experiment, demonstrating the lack of ocular toxicity of triamcinolone acetonide in the rabbit.

Animals↗
PubMed1981

Simulation of massive periretinal proliferation by autotransplantation of retinal pigment epithelial cells in rabbits.

We compared the clinical pattern, the histologic findings, and the electron microscopic appearance of lesions produced by the autotransplantation into rabbit vitreous of freshly harvested and tissue-cultured (250,000) retinal pigment epithelial cells. Both harvested and cultured cells formed intravitreal strands, traction detachments, and retinal puckers, resembling the most prominent features of massive periretinal proliferation in humans. Strands produced by both types of retinal pigment epithelial cells contained cells resembling myofibroblasts which may explain the contractability of the strand. The clinical, histologic, and electron microscopic observations were similar to those found in eyes injected with tissue-cultured skin fibroblasts.

Animals↗
PubMed1980

Respiratory function tests in Aboriginal children on Mornington Island.

Lung function tests using a dry spirometer were performed on school-age Aboriginal children living on Mornington Island in the Gulf of Carpentaria. Although the mean values were below Caucasian standards, they were within the appropriate normal range. There is no evidence in this study to suggest that there is a high prevalence of residual lung damage.

Australia↗
PubMed1980

Treatment of intraocular proliferation with intravitreal injection of triamcinolone acetonide.

We studied the inhibitory effect of triamcinolone acetonide on experimental intraocular proliferation. Autotransplantation of fibroblasts from rabbit rump skin into the vitreous cavity resulted in intravitreal strand formation and traction retinal detachment in 36 of 43 eyes (84%) over a period of three months. A single intravitreal injection of 1 mg of triamcinolone acetonide inhibited fibroblast growth and significantly reduced the number of retinal detachments in 15 of 44 eyes (34%). Retinal neovascularization caused by fibrous strands coming into contact with vacularized retina was also reduced by triamcinolone acetonide (31 of 43 control eyes [72%] vs eight of 44 treated eyes [18%]). Intravitreal corticosteroid therapy may be an important adjunct to the therapy of perforating injuries and massive periretinal proliferation.

Animals↗
PubMed1980

Factors contributing to postweaning diarrhoea in a large intensive piggery.

Some aspects of postweaning diarrhoea (PWD) in a piggery during the first week after early weaning were investigated. A haemolytic enterotoxigenic strain of E. coli (O149:K88:H10) was regularly recovered from piglets with PWD while rotavirus was demonstrated on a number of occasions. Prior to weaning piglets were either free of, or shed very few, haemolytic E. coli in their faeces. However, all piglets were excreting haemolytic E. coli between 5 and 7 days after weaning. The role of rotavirus in PWD was unclear. There appeared to be a direct relationship between serum antibodies to rotavirus in the slow at farrowing and those of the piglets soon after birth. The decline of maternal neutralising antibody to rotavirus coincided with the immediate postweaning period (3 to 5 weeks after birth). This was followed by an increase in antibody levels, 5 to 8 weeks after birth. There was no significant difference in the growth rate between affected and unaffected piglets over a period of 120 days. Medication of water during the first week after weaning had no significant effect on the incidence of PWD in the herd. A change in both the weaner diet and the weaning procedure reduced piglet mortality associated with PWD by more than half.

Animals↗
PubMed1980

Escherichia coli and rotavirus infections in four-week-old gnotobiotic piglets fed milk or dry food.

A haemolytic enteropathogenic E. coli (WG) and pig rotavirus were isolated from a field case of postweaning diarrhoea in pigs. Four-week-old gnotobiotic piglets fed on milk diet were found to be extremely susceptible to infection with WG E. coli. Piglets were less susceptible to the infection immediately after the diet was changed from milk to dry food, and were almost completely resistant 4 days after the change to dry food. There was no difference in the clinical response to infection with WG E. coli when the piglets were fed either a high energy diet or low energy diet. Four-week-old piglets fed milk showed mild symptoms of diarrhoea when inoculated with pig rotavirus. Symptoms were more severe when piglets were inoculated immediately after the change from milk to dry food. Piglets inoculated 4 days after the change of diet showed no symptoms of diarrhoea at all. Under the conditions of these experiments the enteropathogenic E. coli produced a more serious disease than did pig rotavirus. Infection of 4-week-old gnotobiotic piglets with both agents given sequentially produced a diarrhoeal disease that was more severe than that produced by each agent separately.

Animals↗
PubMed1979

Respiratory function in aboriginal school children.

Two hundred and three school-age Aboriginal children living on Cherbourg Aboriginal Settlement have had lung function tested with a dry spirometer. As with other non-Caucasian children, the forced vital capacity (FVC) was about 25% below values for Caucasian children, but the ratio between forced expiratory volume in one second and forced vital capacity (FEV1/FVC ratio), the mean mid-expiratory flow rate (MMEFR) and testing before and after a bronchodilator showed no evidence of widespread airways disease. Analysis of a subgroup of 126 children showed that birthweight, weight at one year of age, and current nutrition did not affect the level of the FVC.

Adolescent↗
PubMed1979

Knowledge and belief in nutrition.

In a nutrition questionnaire, subjects have been given the options of answering questions with yes, no, or don't know. From these responses it has been possible to calculate the levels of their "correct knowledge," their "perceived knowledge" (that is the knowledge that each subject believed he had) and the "accuracy of knowledge". Questions about common nutritional problems were given to physicians, medical students, nurses, and theology students. All groups had a high level of "perceived knowledge," generally greater than 80% for the questions asked, but the accuracy of the knowledge was alarmingly low. The highest level was in physicians, in whom 79% of the perceived knowledge was accurate, but in theology students only 36% of the perceived knowledge was accurate. Two thirds of the "knowledge" of nutrition held by theology students was therefore false by current scientific standards. These findings have implications for future nutrition education.

Educational Measurement↗