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Biomedical subjects

R A Risdon

Publications and source records attributed to R A Risdon.

At least 37 records · Page 2Linked to original sources
PubMed1993

Reflux nephropathy in children submitted to unilateral nephrectomy: a clinicopathological study.

The clinical findings and renal histopathology have been reviewed in children with gross primary vesicoureteric reflux (VUR) submitted to unilateral nephrectomy. Of the 42 children reviewed, sections of the nephrectomy specimens were available in 36. In this series, 34 patients were male and eight were female. The boys included seven in which hydronephrosis was identified by fetal ultrasound. The male patients tended to present earlier and had nephrectomies younger than the females. Segmental scarring was frequent in both males and females, but evidence of dysplastic renal development was confined to the male patients and occurred in the majority (63%). Acquired mechanisms for the induction of segmental renal scarring, involving VUR, intrarenal reflux (IRR) and urinary infection, shown to be important in older children, clearly operate in infancy. However, this study emphasizes that congenital malformation of the kidney is a crucial factor in the development of reflux nephropathy (RN) in this younger age group, particularly in males. Speculation on the significance of the association between renal dysplasia and RN is discussed in relation to observations on the embryological development of the male lower urinary tract.

Age of Onset↗
PubMed1992

Urinary endothelin (ET1) in complete ureteric obstruction in the miniature pig.

Segmental renal scarring occurs in experimental obstructive uropathy in the multipapillary porcine kidney, and segmental abnormalities in renal perfusion are likely to be responsible. This preliminary study examines the urinary excretion of the potent locally active vasoconstrictor endothelin 1 (ET 1) in a pig model of renal obstruction and subsequent relief. Significant urinary excretion of ET 1 from the postobstructive kidney was found to occur after longstanding obstruction. Preglomerular arteriolar stenosis may be the cause of the renal ischaemia in obstruction that is at first reversible but later becomes irreversible if the stimulus persists. ET 1 may be implicated in the pathogenesis of this injury.

Animals↗
PubMed1992

Crescentic glomerulonephritis in children.

Data on patients with crescentic glomerulonephritis (greater than 50% glomeruli with crescents), referred to the Hospital for Sick Children during the past 13 years, were reviewed. Thirty patients (13 male, 17 female) aged 3.7-15.7 years (mean 9.5) were evaluated. Initial clinical features included: oedema (24/30), hypertension (19/30), gross haematuria (15/30), oliguria (15/30) and a decreased glomerular filtration rate (GFR less than 30 ml/min per 1.73 m2) (22/30). Henoch-Schönlein purpura was present in 9 patients, microscopic polyarteritis in 3, polyarteritis nodosa in 1, Wegener's granulomatosis in 1, systemic lupus erythematosus in 1, post-streptococcal glomerulonephritis in 2, mesangiocapillary glomerulonephritis in 7, anti-glomerular basement membrane glomerulonephritis in 2, and 4 were idiopathic. In 10 patients 50%-79% of glomeruli were affected by crescentic changes (group 1) and in the remaining 20, 80% or more (group 2). The crescents were cellular, fibrocellular or fibrous, and the degree of sclerosis was assessed. Patients in both groups were treated with plasma exchange, corticosteroids, anticoagulants, cyclophosphamide and azathioprine in different combinations. On follow-up, 3 patients were dead, 1 was lost to follow-up, 12 were on dialysis/transplant programmes, 4 had a GFR of less than 30 and 10 a GFR of more than 30 ml/min per 1.73 m2. In our experience, 50% progressed to end-stage renal failure. The interval between disease onset and start of treatment was a prognostic factor for outcome. Fibrous crescents were associated with a worse outcome than fibrocellular crescents (P less than 0.05). Outcome was not, however, related to the percentage of glomeruli affected (P greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Mesangiocapillary glomerulonephritis associated with meningococcal meningitis, C3 nephritic factor and persistently low complement C3 and C5.

We report two unusual cases in which mesangiocapillary glomerulonephritis occurred in association with meningococcal infection. C3 nephritic factor, an autoantibody to alternate pathway C3 convertase, was present. Low serum complement C3 and C5 levels were also noted. The depressed complement levels, in conjunction with terminal complement complexes at the upper limit of normal, suggest activation of the early and late complement cascade. We suggest that children presenting with meningococcal infection should have a regular urine examination, as well as full complement measurements performed, in view of the association with hypocomplementaemic mesangiocapillary glomerulonephritis. Similarly, prophylactic penicillin should be prescribed for patients with mesangiocapillary glomerulonephritis and persistently low C5 levels to prevent meningococcal complications.

Adolescent↗
PubMed1991

Risks and benefits of percutaneous biopsy and primary chemotherapy in advanced Wilms' tumour.

Between 1982 and 1988, 36 children with advanced Wilms' tumour underwent percutaneous trucut needle biopsy followed by chemotherapy before definitive surgery. Nephrectomy was performed after a median of 14 weeks of chemotherapy. Substantial reduction in tumour bulk was achieved in 94% of patients. Biopsy morbidity was low and complete concordance between the histological assessment of the tumour in the biopsy specimen and at subsequent nephrectomy was confirmed in 26 of 28 (93%) patients. The overall clinical value of trucut biopsy was 83% (30/36 patients). Survival rates in this high-risk group were comparable to those of children with less advanced disease. Chemotherapy may be the primary treatment of choice for patients with Wilms' tumour. Percutaneous biopsy allows definition of histology in most patients without increasing morbidity.

Adolescent↗
PubMed1991

Cystic renal neoplasms of infancy and childhood: a light microscopical, lectin histochemical and immunohistochemical study.

Cystic renal neoplasms of infancy and childhood, represented largely by cystic variants of nephroblastoma, form a spectrum of clinicopathological entities with differing behaviours. Cystic nephroma and cystic partially differentiated nephroblastoma occupy the benign end of the tumour spectrum, while polycystic Wilms' tumour forms the malignant end. A wide variety of names, reflecting different theories on aetiology, has been applied to the lesions comprising this spectrum, and this has undoubtedly caused confusion in their recognition and classification. We examined five cases of cystic renal tumours in young children which illustrate the entire spectrum, and lectin histochemical and immunohistochemical analysis of these cases showed a close similarity in the pattern of staining of the three variants of cystic tumours. This finding, which has not previously been reported to our knowledge, supports the concept of a close pathogenetic relationship between these tumours.

Biomarkers↗
PubMed1991

Interpretation of biopsies of "normal" urothelium in patients with superficial bladder cancer. MRC Superficial Bladder Cancer Sub Group.

In the course of a Medical Research Council trial of intravesical chemotherapy, biopsies were taken from apparently normal bladder urothelium near to newly diagnosed superficial bladder cancers in 417 patients. Differences were noted in the rates at which histological features were described in different centres. To gain more information about the reproducibility of the pathological findings, a group of 6 pathologists (5 from the UK and 1 from the USA), all having a special interest in urological pathology, were asked to examine a representative sample of 92 slides. They were then asked to re-examine 30 of them after an interval of at least 6 months. At first examination and at re-examination the slides were assessed using a standard proforma. However, the definitions of the categories were left unspecified for the pathologists to use their own criteria. The 5 UK pathologists then met to establish a consensus view of each slide. The results indicated that: (1) The reporting of non-dysplastic changes varied so much between pathologists as to render it of little value to clinical practice. (2) There were wide variations between different pathologists in the reported incidence of dysplastic change. (3) On a second review the pathologists reproduced their own assessment on only 62% of occasions. (4) Even after discussion between pathologists there was no consensus on the diagnosis of mild as opposed to moderate dysplasia. Consensus was reached on all biopsies which showed either severe dysplasia or carcinoma in situ. (5) In adopting a policy of taking urothelial biopsies, urologists should be aware of the imprecision and lack of reproducibility in the interpretation of such biopsies. (6) Biopsies of cystoscopically normal urothelium may not be a useful guide in defining therapy.

Biopsy↗
PubMed1991

Intractable ulcerating enterocolitis of infancy.

Five children (three boys, two girls) presenting in the first year of life with intractable diarrhoea had a number of features in common. All had ulcerating stomatitis, four had partial villous atrophy on small intestinal biopsy, all had colitis characterised by large ulcers with overhanging edges, and four had severe perianal disease; no stool pathogens were detected. Treatment with steroids, sulphasalazine, and azathioprine was unsuccessful. All five required subtotal colectomy. Four were children of consanguinous marriages, two were siblings of Pakistani origin, two were cousins of Arab origin, and the fifth was Portuguese. Although the diagnoses of Behçet's disease and Crohn's disease were considered, it appears that these children represent a distinct inherited condition affecting the whole gastrointestinal tract, particularly the colon.

Behcet Syndrome↗
PubMed1990

Clinicopathologic review of twelve children with nephropathy, Wilms tumor, and genital abnormalities (Drash syndrome).

The clinicopathologic and radiologic features of 12 children with complete and incomplete forms of Drash syndrome are reported. Their common denominator was a nephropathy. Four had the full triad, consisting of nephropathy, Wilms tumor, and genital abnormalities; five had nephropathy and genital abnormalities, and three had nephropathy and Wilms tumor. Of the 11 children who had proteinuria, eight had the nephrotic syndrome. Of the 10 whose condition progressed to end-stage renal failure, seven were less than 3 years of age. The histologic features of Wilms tumor were favorable in all seven children, and the tumor was bilateral in three. Of the nine patients who had genital abnormalities, eight had 46,XY karyotype and either ambiguous genitalia (six patients) or normal female phenotype (two). One other patient had a normal 46,XX female karyotype and phenotype but had both müllerian and wolffian structures and a streak ovary. Nine patients had a distinct pelvicaliceal abnormality not previously reported as a feature of this syndrome. Other congenital abnormalities were aniridia, mental retardation, deafness, nystagmus, and cleft palate. This syndrome must be considered in any infant with unexplained nephropathy, particularly in young phenotypic female infants and in those children with ambiguous genitalia or Wilms tumor with an early presentation.

Child↗
PubMed1990

Thin basement membrane nephropathy as a cause of recurrent haematuria in childhood.

A survey of 69 children presenting with recurrent or persistent haematuria and submitted to percutaneous renal biopsy at this hospital over a 17-year period, was performed to establish the incidence of thin basement membrane nephropathy (TBMN). A diagnosis of primary glomerular disease was established in 44 (IgA nephropathy in 16, Alport's syndrome in 13 and other varieties of glomerulonephritis in 15). Of the remaining 25 patients in whom light microscopical and immunochemical examination revealed no abnormalities, material for electron microscopy was available in 11. In eight of these (five of whom had a family history), TBMN was diagnosed on the basis of ultrastructural morphometric evaluation of glomerular basement membrane thickness. Assuming a similar proportion of the remaining 14 patients with renal biopsy specimens normal by light microscopy had TBMN, the probable frequency of this abnormality in the whole series would be 26%, very similar to that of IgA nephropathy. In the eight TBMN patients the mean glomerular basement membrane thickness ranged between 181 and 236 nm, whilst in 'control' biopsies from children with 'minimal change' nephrotic syndrome or IgA nephropathy, the mean thickness ranged between 242 and 333 nm.

Adolescent↗
PubMed1990

A further family with congenital renal proximal tubular dysgenesis.

A new syndrome of oligohydramnios, Potter's syndrome, and anuric renal failure leading to stillbirth or neonatal death from respiratory failure has recently been described. Histologically, there is renal tubular dysgenesis, especially of the proximal tubules, and apparent glomerular crowding. To date, five families have been reported, in four of which there have been affected sibs and in two parental consanguinity. The disorder is, therefore, thought to be inherited in an autosomal recessive manner.

Adult↗
PubMed1990

Malignant mesenchymoma associated with a congenital lung cyst in a child: case report and review of the literature.

Primary lung tumors are uncommon in children, and malignant mesenchymal tumors form only a small proportion of these. Leiomyosarcomas occur more commonly than rhabdomyosarcomas, whereas malignant mesenchymomas are exceedingly rare. Of the total number of primary pulmonary rhabdomyosarcomas and malignant mesenchymomas of lung reported in children, 50% have occurred in association with congenital lung cysts. The relationship between abnormal morphogenesis and neoplasia is well documented in the kidney. A similar relationship may exist in the lung between cystic parenchymal maldevelopment and embryonal mesenchymal tumors. We report a 4-year-old boy with a malignant mesenchymoma of lung arising within a congenital lung cyst; one similar case has previously been reported to our knowledge.

Child, Preschool↗
PubMed1989

Congenital mesoblastic nephroma, renin production, and hypertension.

Between 1964 and 1987, 12 patients with mesoblastic nephroma were treated. The BP was measured preoperatively in five patients, four of whom were hypertensive. Following nephrectomy, the BP returned to normal. Plasma renin levels were measured in one patient; they were markedly elevated pre-operatively, but returned to normal following tumour excision. Immunoreactive renin staining, using a polyclonal antibody to human renin, was performed in the 12 patients. Staining was positive in ten patients. The most intense staining was noted in the areas of cortex entrapped within the tumour, and in perivascular spaces not associated with entrapped cortex. These findings suggest that hypertension secondary to increased tumour associated renin production is a feature of congenital mesoblastic nephroma.

Child, Preschool↗
PubMed1989

Renal imaging with 99Tcm-labelled DMSA in the detection of acute pyelonephritis: an experimental study in the pig.

Serial renal 99Tcm-labelled dimercaptosuccinic acid (DMSA) scintigrams were acquired 2-58 days after the introduction of urinary tract infection in 33 pigs with experimentally induced vesicoureteric reflux (VUR). In 29 animals VUR was unilateral and in four bilateral, a total of 37 refluxing systems. Animals were killed either at varying intervals after a scintigraphic defect was noted (24 refluxing kidneys) or after a period when sequential scintigrams were normal (13 refluxing kidneys). The appearance of the scintigram acquired on the day prior to death was compared with the renal pathology, each kidney and renal image being divided into three zones (upper, middle, lower) for separate consideration. Of the 37 refluxing systems pyelonephritic lesions were seen in 27, in a total of 61 zones. In the remaining ten kidneys no scintigraphic defect was detected and no pathological lesions were identified either macroscopically or microscopically. Where an abnormality was detected on the scintigram a lesion was always identified in the kidney (sensitivity 100%). Small pyelonephritic lesions in a total of 12 zones in six kidneys were not detected on the scintigram (specificity 82%). Of the lesions undetected by scintigraphy only one occurred in the upper pole.

Acute Disease↗
PubMed1989

Peripheral T-cell lymphoma in childhood. A clinicopathological study of six cases.

A review of the pathological material from 42 children with non-Hodgkin's lymphoma seen over a 44 month period revealed 10 large cell tumours. Of these, six were classified as peripheral T-cell lymphoma, an entity rarely reported in childhood. Three patients were boys and three girls (median age 9.5 years), and extranodal presentation was a feature of two patients. Five had high-grade tumours; of these, three were classified as large cell anaplastic, Ki-1 positive and two as pleomorphic large cell. The remaining patient had a low-grade tumour of angioimmunoblastic type. T-cell subsets were examined in three cases and showed the following phenotypes: CD4-, CD8-; CD4+, CD8-; CD4-, CD8+. Three of the patients with high-grade tumours died, with a mean survival of 22 weeks. The remaining patients are alive and clinically disease-free for between 10 and 24 months after treatment.

Antibodies, Monoclonal↗
PubMed1989

Effect of unilateral vesicoureteric reflux on renal growth and the uptake of 99mTc DMSA by the kidney. An experimental study in the minipig.

The influence of unilateral vesicoureteric reflux (VUR) on renal growth and the uptake of 99mTc DMSA by the kidney has been investigated in a 2-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 = 5), as well as those with raised voiding pressures and abnormal bladder function (n = 7), were investigated 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 renal growth or renal uptake of 99mTc DMSA even in the presence of elevated voiding pressures and abnormal detrusor function.

Animals↗
PubMed1989

Renin messenger RNA localization in congenital mesoblastic nephroma using in situ hybridization.

Renin messenger (m) RNA distribution was studied in congenital mesoblastic nephroma, a usually benign renal tumour of early infancy which may be associated with excess renin production and hypertension. Using in situ hybridization with synthetic radiolabelled oligonucleotide probes combined with immunohistochemical studies, renin expression was found in areas of tumours containing recognizable cortical structures including glomeruli and tubules. Renin mRNA was also detected in vessels and larger vascular spaces within the tumour not associated with cortical structures. Cells in the tumour vessel walls and sinusoids which expressed renin also stained positively for vascular smooth muscle-specific alpha actin.

Female↗