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Biomedical subjects

M Sabha

Publications and source records attributed to M Sabha.

14 recordsLinked to original sources
PubMed1990

Experimental complete ureteric occlusion in sheep: radionuclide renography and histopathologic findings.

Complete ureteric occlusion produces various pathophysiological changes that can be monitored externally by technetium 99m diethylenetriamine penta-acetic acid (99mTc-DTPA) diuretic renography (RDR). Being a dynamic imaging study, it reflects the function of the kidneys and the urodynamics of the urinary tract. The aim of this study was to correlate the changes in parameters of RDR with the histological changes before and after the release of complete ureteric occlusion. In 9 sheep, RDR studies were performed serially after various periods of complete ureteric occlusion (up to 7 weeks) and after release of the occlusion (up to 5 weeks). The histological changes were correlated with changes in RDR. The progressive decrease in renal flow seen on renal images and flow time-activity curves (TACs) was explained by the development of endarteritis and thrombosis of small renal arteries. The progressive decrease in the renal uptake as indicated by the percentage renal uptake and the extraction slope of TAC is related to the progressive damage to the renal parenchyma, initially affecting the collecting ducts and tubules, with increasing interstitial fibrosis in the later stages. Obstruction for 3 weeks or less was associated with moderate damage to the parenchyma from which recovery was possible. Obstruction for 7 weeks was associated with marked damage without chance of recovery. The RDR is a non-invasive technique that can be used to monitor kidney damage after various periods of complete ureteric occlusion and to predict the outcome of surgery before the release of occlusion.

Animals↗
PubMed1990

99mTc DTPA diuretic renography in the evaluation of surgery in chronic schistosomal and non-schistosomal obstructive uropathy.

The selection of patients with chronic obstructive uropathy for surgery is difficult because of problems in identifying true obstruction in a grossly dilated urinary tract. This is especially so in schistosomal (bilharzial) obstructive uropathy. A prospective study of 90 patients (68 with chronic schistosomal and 22 with non-bilharzial obstructive uropathy) was carried out. All patients underwent pre-operative and post-operative radionuclide 99mTc DTPA diuretic renography (RDR). The aims were to assess the value of RDR in the pre- and post-operative management of these patients and whether it could predict the outcome of surgery. Distinctive renogram patterns were identified in patients who required surgical management. These were found useful in monitoring the results and in predicting the outcome of surgery.

Humans↗
PubMed1990

The predictive value of Tc-99m DTPA renography in obstructive uropathy using animal model.

There is no simple analytical test. Radionuclide diuretic renography (RDR), being a dynamic imaging study reflecting the function of the kidney and the urodynamics of the urinary tracts, has the potential to predict the outcome of surgery in obstructive uropathy. In 12 sheep, we occluded one ureter for a maximum of seven weeks and followed up for a maxim of five weeks after release of occlusion. Repeated Tc-99m DTPA diuretic renography studies were performed and the results were correlated with the duration of complete ureteric occlusion. The renal uptake percentage and the extraction slope of the time activity curve (TAC) showed progressive and steady decrease over the period of the occlusion. By the fifth week there was very low uptake (less than 18%) and the TAC was almost flat, suggestive of severe nephropathy. The parenchymal transit time index (PTTI) showed immediate rise after occlusion but with no progressive increase in its value. By the fifth week it dropped down to normal. After release, the recovery of function showed good correlation with the renal uptake percentage and extraction slope of TAC before release of occlusion. Therefore both these parameters, rather than PTTI, can be used to predict the outcome of surgery before the release of complete obstruction of the ureter.

Animals↗
PubMed1989

The effect of ureteral distension on peristalsis. Studies on human and sheep ureters.

Isolated sheep and human ureteral preparations (from patients with bilharzia) were subjected in-vitro to graded elongation and the effect on tension and spontaneous peristaltic frequency was assessed. Sheep specimens were obtained from three locations: the intra- and extrarenal portion of the pelvis and distal ureter. Elongation (stretch) induced an increase in spontaneous frequency only in pelvic ureteric specimens, but not in the distal ureter. Basal tension increased exponentially with stretch and most markedly in the distal sheep ureter and also in human preparations. Active tension (amplitude of phasic contractions) increased with stretch in specimens from all locations and reached a maximum at 110-115% elongation. These data suggest that acute distension of the ureter increases frequency of peristaltic waves only in the intrarenal parts of the ureter. Acute obstruction in renal colic can induce hypermotility in terms of increased frequency and force of contraction.

Animals↗
PubMed1989

Comparison of 99Tcm-mercaptoacetyltriglycine and 131I-orthoiodohippurate in determination of effective renal plasma flow (ERPF).

Recent studies have suggested that 99Tcm-labelled mercaptoacetyltriglycine (99Tcm-MAG3) is a potential replacement for 131I-orthoiodohippurate (131I-OIH). The two radiopharmaceuticals were studied in 19 patients with varying degrees of renal impairment, for comparison of effective renal plasma flow (ERPF). All patients were injected i.v. with 2-3 mCi 99Tcm-MAG3 and 250-300 microCi of 131I-OIH simultaneously in separate arms to avoid any chemical incompatibility. Serial digital images were acquired simultaneously for 99Tcm-MAG3 and 131I-OIH at 15 s per frame for 30 min. The renogram curve was generated and ERPF value was calculated for each kidney using both radiopharmaceuticals and applying the same computer program (Schlegel's program). In all cases, the 99Tcm-MAG3 and 131I-OIH renogram curves were quite similar. The values of ERPF of 99Tcm-MAG3 were not significantly different from those of 131I-OIH studies (paired t test, p less than 0.01). The correlation coefficient between the two methods was 0.95 (p less than 0.001) with a linear regression equation Y = -12.96 + 0.995X, where Y = ERPF determined by 131I-OIH and X = ERPF determined by 99Tcm-MAG3. This study indicates that 99Tcm-MAG3 is a useful 99Tcm replacement for 131I-OIH in the determination of ERPF and generation of renogram curves.

Adolescent↗
PubMed1988

Mast cells and histamine responses of the ureter, ultrastructural features of cell-to-cell associations and functional implications.

In this study of normal adult human and ovine ureters, a characteristic distribution of a large population of typical mast cells was described by light and electron microscopy. Pharmacological studies were used to ascribe a functional role for these cells in normal and pathological states. In the structural investigations typical mast cells with their cytoplasm packed with characteristic electron dense granules were found in close vicinity to smooth muscle cells. A close association between mast cells and a fibroblast like La-cell and non myelinated nerve fibers was noted. The prevalence of mast cells was higher in human ureters. Human and sheep ureteral ring preparations exhibited spontaneous rhythmical contractions in vitro. Addition of histamine (10(-6)-10(-5) M) induced an increase in the frequency of contractions and enhanced the basal tone particularly in human samples. It is likely that histamine under pathological conditions such as renal colic and inflammatory reactions is released from mast cells within the ureter and induces a state of forceful contractions and pain fibre stimulation.

Animals↗
PubMed1988

The effect of urothelial damage on ureteric motility. An ultrastructural and functional study.

Evidence of a leaky urothelial barrier in bilharzial uropathy is presented. The ultrastructural basis of this concept is demonstrated together with its functional consequences. The study was conducted on 4 ureters obtained at surgery from patients with non-functioning kidneys due to chronic bilharzial infections. Six normal ureters from kidney donors served as controls. Light and electron microscopic studies showed a reduced thickness of the transitional epithelium together with localised disruption of intercellular junctions and infiltration of red blood cells. The functional studies involved in vitro demonstration of stable phasic peristaltic contractions which were fundamentally altered by the addition of urine. The changes in motility included increase in contractile frequency and elevation of basal tone, inducing a state of hypermotility which could be equated with ureteric spasm. These changes were partly reversible upon administration of the histamine l-blocker, mepyramine. Evidence is presented to show that these changes might be induced in vivo by histamine released from mast cells triggered by urine leaking through a damaged urothelial barrier. The functional consequences (pain, spasm) are discussed.

Epithelium↗
PubMed1988

Urodynamic evaluation of calcified bilharzial bladders.

The functioning of 100 bladders with bilharzial calcification has been urodynamically studied and compared to 30 non-bilharzial healthy males of the same age group. Uroflowmetry, fluid cystometry and pressure flow studies were performed in all bilharzial and control patients. No significant urodynamic differences were found between the bilharzial patients and the control group except that bilharzial patients showed residual urine (mean 100 ml) and delayed first sensation (mean 250 ml). Cystoscopy and multiple deep bladder biopsies were conducted in all bilharzial patients. Histology showed that bladder calcification involves mainly the mucosa and submucosal layers. It was only occasionally that calcified ova were seen in the muscle layers. Since the bladder muscles are largely intact, it is not surprising that the detrusor function is normal even though the bilharzial bladder wall is severely calcified.

Calcinosis↗
PubMed1988

Chronic urinary schistosomiasis: patterns of abnormalities in radionuclide Tc-99 m DTPA diuretic renogram.

The aim of this study was to describe the abnormal morphological and functional patterns observed in radionuclide diuretic renograms (RDR) in patients with chronic urinary schistosomiasis. A retrospective analysis of RDR for 92 patients was made. It revealed the following abnormalities: A) Morphological changes observed in the images: Pelvicalyceal retention of tracer (and dilatation) was seen in 68% of kidneys. Calyceal retention alone was seen in 5% and pelvic retention alone in 9%. An atrophic kidney was noted in 5%, nephropathic pattern in 3% and normal kidneys in 10%. Ureteric retention of tracer was seen in 64% of ureters. This was frequently associated with pelvicalyceal retention (61%) and this abnormality was bilateral in 44% of the urinary systems. B) Functional changes observed in the time activity curves: Non-obstructive delayed excretion was noted in 71% of kidneys. An obstructed kidney pattern nonresponsive to lasix was seen in 12%, plateau curve due to nephropathic kidney in 3% and atrophic kidney pattern in 4% of kidneys.

Adult↗
PubMed1987

Patterns of stromal elements in an implanted ureteric transitional cell carcinoma. An immunohistochemical and ultrastructural study.

The results of the study of three implanted ureteric tumors from a primary transitional cell carcinoma of the renal pelvis are reported. Using both light microscopic immunohistochemistry and transmission electron microscopy, the stroma of the tumor showed consistent evidence for the production of at least its collagenous component by the neoplastic cells. Our findings argue with the notion that occasional fibroblasts and other cells of mesenchymal origin could play a major role in this phenomenon. Therefore, it seems plausible to suggest that what is happening in these tumors is similar to the behavior of malignant cells in scirrhous 'infiltrating' carcinoma of the breast and other sites.

Carcinoma, Transitional Cell↗
PubMed1986

Huge bladder carcinoma successfully treated with hydrostatic pressure technique. A case report.

A 64-year-old man presented with acute urinary retention and anasarca due to noninvasive multiple papillary transitional cell carcinoma filling the whole bladder cavity and obstructing both ureters. He was treated with hydrostatic pressure distension. A dramatic response occurred, with complete disappearance of the tumour within one month of the treatment.

Carcinoma, Transitional Cell↗
PubMedDate not supplied

The value of parenchymal transit time index of Tc-99m DTPA diuretic renography in the evaluation of surgery in chronic bilharzial obstructive uropathy.

Selection of patients with chronic bilharzial uropathy (CBU) for surgery is a difficult problem due to the presence of grossly dilated urinary tracts without a significant obstruction in most of the cases. In this prospective study of 40 patients with CBU, the time-activity curve (TAC) patterns of the pre- and postoperative Tc-99m DTPA diuretic renography (RDR) studies were compared with the corresponding parenchymal transit time indices (PTTI). The aims were to find out which of these renographic parameters was more accurate in identifying obstruction and which was better in predicting the outcome of surgery. PTTI was more sensitive than TAC in identifying obstruction (96% and 92%, respectively) but it was less specific (78% and 98%). The detection accuracy of RDR for obstruction using TAC patterns was 96% compared to 84% using PTTI. Being independent of renal uptake function, PTTI could not predict the outcome of surgery as TAC could. In contrast to PTTI, TAC patterns could differentiate obstructed kidneys from severely nephropathic kidneys. However, PTTI was useful in identifying kidneys with residual nephropathy.

Adult↗