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Biomedical subjects

R A Risdon

Publications and source records attributed to R A Risdon.

At least 73 records · Page 4Linked to original sources
PubMed1975

Transfusional iron overload: the relationship between tissue iron concentration and hepatic fibrosis in thalassaemia.

The interrelationships between liver iron concentration, the duration of iron-loading, and hepatic fibrosis, assessed morphometrically, have been studied in 32 specimens of liver obtained from 19 heavily transfused patients with thalassaemia major whose age ranged from 4 to 19 yr. Similar observations were made in a matched group of thalassaemic patients treated with long-term chelation therapy. The degree of liver damage ranged from very slight increase in fibrous tissue to severe fibrosis and cirrhosis. The severity of the fibrosis was closely correlated both with liver iron concentration and with age. While the relationship between fibrosis and age was linear, both the severity and the rate of fibrosis were exponentially related to liver iron concentration, damage accelerating as liver iron concentration exceeded 3 per cent, dry weight. By producing a modest but significant reduction in liver iron concentration chelation therapy resulted in a disproportionate but predictable retardation in the progression of the fibrosis. The factors affecting the distribution of iron between parenchymal and reticuloendothelial cells were also examined. In general stainable iron was uniformly distributed between parenchymal and reticuloendothelial cells from the early stages of iron-loading. Parenchymal siderosis was relatively heavier in splenectomised patients and in patients with liver iron concentrations above 3 per cent, dry weight than in non-splenectomised patients or patients with liver iron levels of less than 3 per cent, dry weight, but this did not affect the severity of the fibrosis. The relevance of these findings to the traditional concepts of the pathology of transfusional siderosis is discussed.

Adolescent↗
PubMed1975

Familial opsonization defect associated with fatal infantile dermatitis, infections, and histiocytosis.

Members of four generations of a family had a defect of serum opsonization for yeast phagocytosis consistent with dominant inheritance. 2 were healthy, one had chronic osteomyelitis, and the fourth developed a fatal illness in infancy characterized by exfoliative dermatitis, diarrhoea, multiple bacterial infections, and failure to thrive, which resembled the two prevously reported cases with this opsonization defect. At necropsy the infant also had lymphoid depletion, which was possibly secondary, and massive histiocytic infiltration.

Adult↗
PubMed1975

Computer card morphometry of jejunal biopsies in childhood coeliac disease.

The histological changes in 95 jejunal biopsy specimens from children have been analyzed by a new mporphometric technique. The microscope image of the specimen is traced directly onto computer data cards. A simple sketch records accurate quantitative data in a matrix of 840 points, retaining the spatial arrangement of the tissue components. The data are fed via an optical mark data card reader, into a mini-computer. FORTRAN IV programs allow calculation of surface area, villous heights, and component volumes in metric units, and of volume proportions, volume-to-volume ratios, and surface-to-volume ratios. Pictorial and numerical printouts are produced, which are suitable for inclusion in the patient's notes. Jejunal biopsies from 37 controls and 26 untreated coeliac patients were clearly distinguished morphometrically. Sixteen pairs of biopsies from coeliac patients on long-term gluten-free diets before, and 12 weeks after, the reintroduction of dietary gluten significantly reflected the effects of gluten challenge. Comparison of control and abnormal biopsies showed a spatial redistribution of the components, more than a change in their absolute amounts. There was no significant differences in the total epithelial volumes in controls, treated or untreated patients, suggesting that the mucosal lesion in coeliac disease is not a true atrophy.

Adolescent↗
PubMed1974

Long-term chelation therapy in thalassaemia major: effect on liver iron concentration, liver histology, and clinical progress.

A prospective trial of continuous chelation therapy in children with homozygous thalassaemia on a high transfusion regimen was started in April 1966. The effect of treatment on iron concentration in the liver and on hepatic histology was examined in 49 biopsy specimens obtained from nine chelator-treated patients and nine control patients between April 1966 and April 1973.Chelation therapy was associated with a significant reduction in liver iron concentration, and by the end of the trial the values for the two groups showed no overlap. A similar difference was seen in the amount of hepatic fibrosis, which showed little or no change in the chelator-treated patients but was progressive in the controls.No major clinical differences were seen, probably because both groups included several older children who were heavily loaded with iron at the start of the trial. Among the younger patients, however, puberty was delayed in four of five controls but in only one of four chelator-treated children. Prepubertal growth rate was significantly greater in the chelator-treated patients than in the controls.

Biopsy↗
PubMed1974

Quantitation of the histological changes found in small intestinal biopsy specimens from children with suspected coeliac disease.

The histological appearances in 85 peroral small intestinal biopsies from children have been analysed quantitatively by the method of Dunnill and Whitehead (1972). As applied to such biopsy specimens, this technique provides indices of both the mucosal volume and of the mucosal surface-to-volume ratio. When compared with controls, ;flat' biopsies from children with untreated coeliac disease invariably showed much smaller surface-to-volume (c:lh) ratios. The mucosal volumes (h) of these biopsies were, however, significantly increased. Specimens showing less marked abnormalities (socalled ;partial villous atrophy') had c:lh ratios in an intermediate range, but, like the biopsies from untreated coeliacs, h values were significantly increased. In morphologically normal biopsies correlation of surface-to-volume ratios with age showed that c:lh ratios were significantly smaller in younger children. Some of these lower c:lh ratios overlapped the range observed in abnormal biopsies showing partial villous atrophy. However, in the atrophic biopsies additional histological changes, such as abnormalities of the surface epithelial cells and an increased inflammatory cell infiltration of the lamina propria, were invariably present. Slight changes in biopsies from children under 2 years of age should, therefore, be interpreted cautiously, and should not necessarily be regarded as pathological on the evidence of the villous pattern alone. The quantitative technique employed proved reproducible under normal working conditions, and its greatest practical value would appear to be in following accurately serial changes in biopsies from the same patient.

Adolescent↗
PubMed1973

Nature of hyperacute (accelerated second set) rejection in dog renal allografts and effects of heparin on rejection process.

Renal allografts were exchanged between unrelated mongrel dogs after previous sensitization with skin and kidney grafts from the same donors. Rapid rejection of the renal allografts was associated with the accumulation of platelets and leucocytes in the peritubular and glomerular capillaries but fibrin deposition was not demonstrated.Heparin infusion delayed but did not prevent the rejection process.

Animals↗
PubMed1971

Renal dysplasia. I. A clinico-pathological study of 76 cases.

The clinical and pathological findings in 150 children submitted to partial or total nephrectomy have been reviewed. Histological examination of the kidney removed at operation showed evidence of renal dysplasia in 76 (51%). These 76 patients were divided into three main groups on the basis of the pathological changes found in the kidney and the associated urinary tract anomalies. In group 1, gross cystic renal dysplasia was associated with absence or atresia of the renal pelvis and ureter. In group 2, renal dysplasia was segmental; the ureter, although patent, had some anatomical or functional abnormality which resulted in urinary stasis or reflux. In many of these patients dysplasia was confined to the upper pole of a ;duplex' kidney which was drained by an ectopic ureterocele. In group 3, renal dysplasia was associated with obstruction of the lower urinary tract, most commonly by posterior urethral valves. In group 1 dysplasia was total, involving the whole kidney, whilst in groups 2 and 3 dysplasia tended to be segmental; in the majority some normal renal tissue was present. Pyelonephritis was a very common complication, but was present only in patients from groups 2 and 3, in whom a lumen was present in the draining ureter, and not in patients from group 1 in whom the ureter was atretic or absent, and the kidney not functioning. It appears that urinary obstruction, stasis, or reflux are the principal factors predisposing to and promoting pyelonephritis in dysplastic kidneys. There seems to be no reason to suppose that dysplastic renal tissue is abnormally susceptible to infection since pyelonephritic changes were lacking in those cases in which dysplasia was most severe.

Cartilage↗