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Biomedical subjects

R A Risdon

Publications and source records attributed to R A Risdon.

At least 55 records · Page 3Linked to original sources
PubMed1988

Renin in mesoblastic nephroma: an immunohistochemical study.

Congenital mesoblastic nephroma (CMN) is the most common renal tumor of early infancy. It is usually evident at birth as an abdominal mass and is composed of spindle-shaped cells resembling smooth muscle cells and fibroblasts. There is macroscopic and microscopic infiltration of the surrounding kidney and entrapped tubules and glomeruli are common at the edge of the tumor. In this report, we describe a case of CMN associated with hyperreninaemia and hypertension. We examined the tumor from this case and 11 other cases for the presence of renin using a polyclonal antibody to human kidney renin. Hypertension was present in three of four additional cases for which records were available. Immunoreactive renin was present in ten of the 12 cases studied. In all of these cases, intense staining was present in vessels within the areas of the trapped cortex. In seven cases, renin was identified in the walls of vessels within the tumor itself without identifiable adjacent cortical structures. These findings indicate that CMN may often be associated with primary reninism in early infancy.

Humans↗
PubMed1988

Travellers' diarrhoea among children returning to the United Kingdom from visits abroad.

Between January 1984 and March 1986, 10 children aged between 7 and 56 months were admitted to Queen Elizabeth Hospital for Children in London with chronic travellers' diarrhoea, after visiting the Indian subcontinent, France or Morocco. All the children were born in the United Kingdom and had been in good health before their journey abroad. On return to England most of these children were malnourished and two of them (twins) had a post-infective, tropical malabsorption-like syndrome. There was a high incidence of positive stool cultures and, on small intestinal biopsy, histological abnormalities were present in six. Children from the United Kingdom travelling abroad are at risk of developing severe travellers' diarrhoea, with serious consequences to their health and nutrition. There is a need for intensive parental education before travelling and this could be achieved through community health workers.

Bacterial Infections↗
PubMed1987

The small scarred kidney of childhood. A congenital or an acquired lesion?

The vast majority of small segmentally scarred kidneys seen in childhood are now recognised to be associated with vesicoureteric reflux and the term "reflux nephropathy" has been accorded general recognition as a description of this renal lesion. With regard to the pathogenic mechanisms responsible for the scarring process, the possible roles of intrauterine renal maldevelopment, bladder dysfunction, functional urinary obstruction and infection in relation to vesicoureteric reflux and the associated phenomenon of intrarenal reflux must all be considered. It is probable that in different clinical circumstances all of these factors may be important to varying degrees and discussion of their contributions to the spectrum of reflex nephropathy is the basis of this communication.

Child↗
PubMed1987

Effects of vesicoureteric reflux on renal growth and function as measured by GFR, plasma creatinine and urinary concentrating ability. An experimental study in the minipig.

The influence of vesicoureteric reflux (VUR) on renal growth and function measured by glomerular filtration rate (GFR), plasma creatinine concentration and urinary concentrating ability has been examined in a simple one-kidney model in the growing minipig over a period of approximately 5 months. Animals with reflux in association with low voiding pressures and normal bladder function (n = 6), as well as those with raised voiding pressures and abnormal bladder function (n = 5), were investigated together with appropriate non-refluxing controls (n = 12). Urinary infection and renal scarring were avoided since these factors may affect kidney function and growth independently. Statistical tests of difference failed to demonstrate any effect of VUR on 51Cr EDTA GFR or renal growth even in the presence of elevated voiding pressures and abnormal detrusor function. However, a significant association between VUR and reduced urinary concentrating ability was shown.

Animals↗
PubMed1987

Microvascular changes in the early stage of reflux pyelonephritis. An experimental study in the pig kidney.

Renal microvascular changes were studied in the pig kidney during the initial stage of reflux pyelonephritis. In 10 piglets vesicoureteric reflux was surgically induced. The animals were then infected with a strain of Escherichia coli and sacrificed 2 weeks following the initiation of infection. Following injection of the kidneys with Microfil, microvascular changes were investigated by a combined stereomicroscopic, microradiographic and histological technique. Renal microcirculation was found to be impaired in the areas involved in the acute inflammatory process, owing to the compression of glomeruli, small peritubular capillaries and vasa rectae by the ensuing interstitial oedema. These findings indicate that acute focal ischaemia caused by microvascular obstruction could be an important factor in the mechanism of renal damage in reflux pyelonephritis.

Angiography↗
PubMed1985

The relationship between renal parenchymal mass and absolute quantitation of 99Tcm-DMSA uptake. An experimental study in the growing pig.

Five Gottingen minipigs from the same litter aged 1 month entered the study and right nephrectomies were performed at staggered intervals between weeks 1 and 5. Absolute renal uptake of 99Tcm-DMSA, expressed as a percentage of the administered dose, was recorded in each animal weekly before right nephrectomy and at weekly intervals for 5 weeks post-nephrectomy. Before nephrectomy absolute renal uptake of 99Tcm-DMSA ranged between 16.8 and 21.5% (mean 18.6%) per kidney with no difference between right and left kidneys. After right nephrectomy, uptake in the left kidney approximately doubled within 1 week. No correlation was shown between renal parenchymal mass and absolute 99Tcm-DMSA uptake in paired or solitary normal kidneys undergoing growth or compensatory growth.

Animals↗
PubMed1984

Methotrexate in the treatment of metastatic and recurrent primary transitional cell carcinoma.

Results in a series of 60 patients with recurrent or metastatic transitional cell carcinoma of the bladder confirm that methotrexate is active as a single agent. Over-all, 43 per cent of the patients with measurable metastases and 28 per cent with recurrent primary tumors responded for an average of 6 months. Response rates in both groups were influenced by the stage of the primary tumor.

Aged↗
PubMed1983

Germ cell tumours of the testis.

The application of new techniques, particularly the identification of tumour markers, in the study of testicular germ cell tumours is presently leading to a reassessment of opinions regarding the origin and classification of these neoplasms. Some aspects of this controversy are examined.

Chorionic Gonadotropin↗
PubMed1983

Renal oncocytoma. A review of the literature and report of an unusual multicentric case.

Renal oncocytoma is a rare tumour of the kidney composed exclusively of large polygonal cells with eosinophilic, granular cytoplasm. Ultrastructurally they are distinguished by the presence of large numbers of mitochondria and histochemically by abundant oxidative enzymes and adenosine triphosphate. Macroscopically these tumours are usually light brown in colour and commonly exhibit a dense central area of fibrous scarring, with fibrous trabeculae extending from this central zone in a stellate fashion. Renal oncocytomas are commoner in males than females (sex ratio 2:1) and although the age range at presentation is wide, there is a peak incidence in the seventh decade. The prognosis following surgical removal is excellent, despite the fact that many of these tumours are large. Invasion of the perirenal fat and the renal vein and metastatic spread to regional lymph nodes is documented, but death from metastatic disease is rare. The great majority of renal oncocytomas reported are solitary. We describe a multicentric renal oncocytoma, the sixth so far reported.

Adenoma↗
PubMed1980

T3 bladder cancer--the case for salvage cystectomy.

Seven hundred and four patients with bladder cancer treated by radiotherapy at the London Hospital between 1965 and 1974 have been followed for a minimum period of 5 years. Invasive tumours were usually treated by radical radiotherapy. Cystectomy was reserved for patients whose tumours did not respond to radiation, recurred later on, or who developed complications from radiotherapy. The crude 5-year survival rate for T3 tumours in this series was 38%--similar to that obtained in other centres using pre-operative radiation followed by cystectomy, but this overall figure conceals the important difference between 2 distinct tumour populations. Nearly half of these tumours appear to be radiosensitive, giving a 56% crude 5-year survival rate for T3 tumours. The remainder are radioinsensitive, with only a 17% crude 5-year survival rate for T3 tumours. When there is a good initial response to radiotherapy there would seem to be no necessity to insist upon cystectomy.

Aged↗
PubMed1979

The pathogenesis of reflux nephropathy.

In an experimental study, the scars of chronic pyelonephritis have been shown to be caused by infected intrarenal reflux. Intrarenal reflux occurs in the presence of vesicoureteric reflux and a renal papilla having special morphological characteristics predisposing to this phenomenon. Such papillae occur predominantly in the polar regions of the kidney where large pyelonephritic scars are most commonly seen. The clinical implications of this pathogenic mechanism are discussed.

Animals↗
PubMed1978

Gluten challenge in treated coeliac disease.

Thirty-two children with a past diagnosis of coeliac disease were reinvestigated by means of gluten challenge. They had received a gluten-free diet for a mean period of 6-5 years (range 0-25-11-0) before gluten challenge, and had a mean age of 9-9 years (range 3-0-15-3) at the onset of challenge. Small intestinal biopsies were performed before and after the gluten challenge (at least 10 g natural gluten per day for 3 months in the majority) and, as judged by light microscopy and morphometric techniques, coeliac disease was confirmed in 25 (78%) of the 32 patients; challenge was continued in the remaining 7 for a total period of 2 years when biopsies were repeated in 6 children and all were normal. Serum and RBC folate, serum iron, Hb level, and clinical symptoms were unpredictable variables in identifying children who developed gluten-induced enteropathies. The social and emotional effects of gluten challenge are discussed. The results highlight the importance of gluten challenge and intestinal biopsy in the diagnosis of coeliac disease and strongly suggest that a normal biopsy after a 3-month gluten challenge (as described above) excludes coeliac disease.

Adolescent↗
PubMed1975

Renal papillary morphology and intrarenal reflux in the young pig.

Intrarenal reflux in piglets has been related to the morphology of individual renal papillae. These studies show that intrarenal reflux occurs only in the presence of the more extensively fused papillae found predominantly at the upper and lower poles of the kidney. These papillae each have a flattened or concave area cribrosa with large open papillary ducts which cannot be closed by a rise in intracalyceal pressure. In contrast intrarenal reflux never occurs into cone-shaped papillae seen most commonly in the mid-zone of the kidney, which have easily closed, oblique, slit-like papillary duct orifices. The significance of these findings in relation to the genesis of chronic pyelonephritic scarring is discussed.

Animals↗
PubMed1975

Renal papillary morphology in infants and young children.

The morphology of the renal papillae was studied in a series of necropsy kidneys from infants and young children, and related to experimental data obtained in piglets. As in the piglet, extensively fused papillae of the type associated with intrarenal reflux occurred almost exclusively at the upper and lower poles of the kidney. However, the incidence of this kind of papilla was much lower in the children's kidneys, and in over a quarter of the specimens examined only cone-shaped papillae were found; this latter type of papilla is never associated with intrarenal reflux in the piglet.

Age Factors↗
PubMed1975

Renal hypoplasia and dysplasia: a radiological and pathological correlation.

Forty-nine cases of congenitally small (hypoplastic) or maldifferentiated (dysplastic) kidneys have been reviewed. From a detailed consideration of the radiological and pathological data in these patients a classification of renal hypoplasia and dysplasia has been derived which is based not only on the abnormalities in the kidney, but also on the associated anomalies seen in the ureters and in the lower urinary tract.

Child, Preschool↗