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Biomedical subjects

S C Tiwari

Publications and source records attributed to S C Tiwari.

At least 73 records · Page 4Linked to original sources
PubMed1995

Clinical profile and course and outcome of late acute rejection episodes in living-related-donor renal allograft recipients.

We prospectively monitored clinical data and renal function at monthly intervals in 165 patients who had received living-related-donor renal allografts in our institution between January 1981 and December 1991 and had a functioning allograft for 1 year or longer. During a mean follow-up period of 47.2 (range 13-155) months, 32 patients (17.2%) developed late acute rejections, of which 14 (43.7%) were asymptomatic. Amongst the symptomatic late acute rejections, worsening of hypertension was the commonest finding, being present in 11 (61.1%) patients, followed by oliguria in 8 (44.4%) and weight gain in 7 (38.8%) patients. Of these 32 late acute rejections, as many as 28 (87.5%) showed a response to antirejection therapy with high-dose steroids: 5 (15.6%) a complete response and 23 (71.9%) a partial response. The response rate was 100% if it was the first acute rejection (20% complete and 80% partial), 78.6% if it was the second (14.3% complete and 64.3% partial), and no or only a partial response to treatment if it was the third acute rejection episode. On long-term follow-up, patients who had responded to to antirejection treatment had a significantly better graft survival as compared with nonresponding patients: 76 and 27%, respectively. Our observations suggest that routine monitoring of the renal function at frequent intervals is essential for early diagnosis and treatment of acute rejections, even during the late posttransplant period. The chances of a response to antirejection therapy are higher during the first episode of late acute transplant rejection as compared with second or a third late rejection event.

Acute Disease↗
PubMed1994

pH-dependent solubility and assembly of microtubules in bovine brain extracts.

Alkaline pH favors the assembly of microtubules (MTs) in marine egg extracts [Suprenant and Marsh, 1987: J. Cell Sci. 184:167-180; Suprenant, 1989: Exp. Cell Res. 184:167-180; 1991: Cell Motil. Cytoskeleton 19:207-220] and mammalian brain extracts [Tiwari and Suprenant, 1993: Anal. Biochem. 215:96-103], even though the assembly of purified microtubule protein (MTP) from both of these sources is favored at slightly acidic pH. The present investigation examines whether alkaline pH has a direct or indirect effect on MT nucleation and growth in soluble brain extracts. Cell-free extracts were prepared from bovine cerebral cortex, and a nucleated assembly assay was used to demonstrate that MT assembly in brain extracts is favored at slightly acidic pH. The increase in MT mass found at alkaline pH is due to an increase in the solubility of tubulin not an increase in the extent of assembly. On average, 47.7 +/- 11.3% of the total tubulin is soluble at pH 7.2, while only 30.9 +/- 8.9% of the tubulin is soluble at pH 6.8. A model is proposed that indicates how microtubule proteins from both mammalian brain and marine eggs may be associated with pH-dependent factors.

Animals↗
PubMed1994

Clinicopathologic course of hepatitis B infection in surface antigen carriers following living-related renal transplantation.

We present the clinical course, serology, and histopathology of 17 living-related renal allograft recipients who were hepatitis B surface antigen (HBsAg) positive at the time of transplantation. Although 14 patients were hepatitis B e antigen (HBeAg) positive, none had clinical hepatitis at the time of transplantation. All patients were receiving moderate doses of prednisolone and azathioprine only. At the mean short-term follow-up of 70 months (range, 6 to 132 months), none of the patients had seroconversion to antibody to HBsAg. Four patients died due to extrahepatic complications between 16 and 50 months following transplantation. Of these, three had normal liver function at the time of death and one had portal tract infiltration by chronic inflammatory cells. One patient died due to fulminant hepatitis at 6 months after transplantation. Of the remaining 12 patients, although 11 were HBeAg positive, only two developed chronic active hepatitis. Our short-term follow-up data suggest that chronic liver disease is not a frequent complication following living-related renal transplantation in HBsAg carriers. In addition, the presence of HBeAg at the time of transplantation does not predict a bad prognosis. Thus, in a living-related renal transplant program, asymptomatic carriers of HBsAg with positive HBeAg are not a contraindication for renal transplantation.

Actuarial Analysis↗
PubMed1994

Primary pelvic hydatid cyst presenting with obstructive uropathy and renal failure.

Primary pelvic hydatid cyst is a rare entity. Pelvic hydatid cysts usually present with pressure symptoms involving adjacent organs (bladder and rectum usually). A case of primary pelvic hydatid cyst presenting with obstructive uropathy leading to chronic renal failure is presented. A combination of preoperative albendazole therapy of 1.2 g/day for 8-12 weeks and surgical excision were effective in alleviating the symptoms and improving the renal function.

Adult↗
PubMed1993

A pH- and temperature-dependent cycling method that doubles the yield of microtubule protein.

This report describes a procedure for the isolation of microtubules (MTs) and microtubule-associated proteins from mammalian cultured cells and tissues. This method relies on the discovery that the solubility of brain tubulin is pH-sensitive. In this report, we examined tubulin solubility over a broad pH range and discovered that the amount of soluble tubulin increased by 240% as the pH was raised from 6.0 to 8.0. Quantitative immunoblotting revealed that there was an almost equal partitioning of tyrosinated and acetylated alpha-tubulin isotypes at the higher pH. These observations were incorporated into a new procedure for the purification of microtubule protein (MTP) from bovine brain and mouse B16 cultured melanoma cells. Morphologically, and in terms of polypeptide composition, this MTP is indistinguishable from that prepared by a glycerol-cycling method (21). Moreover, our new method of pH- and temperature-cycling yields almost twice as much MTP as that obtained by other cycling methods.

Acetylation↗
PubMed1993

Biliary bile acids in cholelithiasis and carcinoma of the gall bladder.

The role of biliary deoxycholate as an endogenous carcinogen and the possible association between cholelithiasis and the subsequent development of carcinoma of the gall bladder is unclear. This paper describes biliary bile acid analysis performed on three groups of patients, 10 with cholelithiasis, 10 with carcinoma of the gall bladder and 10 control patients. This is the first report of bile acid changes in carcinoma of the gall bladder. In these 30 patients the total bile acids concentration was highly variable (11.44-53.68 mg/ml). The mean ratio of primary to secondary bile acids was 3.5:1. This ratio was, however, significantly higher in cholelithiasis than in the control group (5.34:1; P < 0.001); patients with carcinoma of the gall bladder had significantly higher secondary bile acids (1:1; P < 0.001). This is due to a marked increase in the secondary bile acids and indicates that raised biliary deoxycholate concentrations are present in patients with carcinoma of the gall bladder and therefore may well be a factor in carcinogenesis.

Bile Acids and Salts↗
PubMed1993

Idiopathic adult focal segmental glomerulosclerosis: a clinicopathological study and response to steroid.

A total of 65 adult cases (53 males, 12 females) with biopsy-proven focal segmental glomerulosclerosis (FSGS) were studied. Hypertension, ascites and haematuria were seen in 13, 12 and 24 cases, respectively. Decreased creatinine clearance at presentation was found in 9 cases. Mean proteinuria per day, serum cholesterol and total protein were 7.5 +/- 4.3 g, 388.95 +/- 213.4 mg% (10.11 +/- 5.55 mmol/l) and 5.27 +/- 1.1 g% (0.527 +/- 0.11 milligram), respectively. Mesangial proliferation was seen in 13 cases and hilar sclerosis in 5. Fifty percent showed positive immunofluorescence; IgM in 10, C3 in 8, and IgG in 2. Forty-two cases could be followed (mean 32 months), out of which 38 had nephrotic syndrome and were treated with prednisolone; 58% showed response (31% complete remission and 27% partial remission). One patient in each group of responders and nonresponders had renal failure at the end of follow-up. Hypertension, degree of proteinuria, mesangial proliferation, degree of tubular atrophy and immunofluorescence findings did not significantly affect the response to steroids. We conclude that a group of patients with idiopathic adult FSGS has a favourable response to steroids, which cannot be predicted clinically.

Adolescent↗
PubMed1993

Anti-neutrophil cytoplasmic antibody (ANCA) in necrotising vasculitides with renal involvement.

Anti-neutrophil cytoplasmic antibody (ANCA) was detected in sera of 20 out of 32 patients with necrotising vasculitides involving the kidneys and other organs. It was of high titre and cytoplasmic type in Wegener's granulomatosis (8/9); and of low titre and cytoplasmic or perinuclear type in systemic polyarteritis (6/12), renal limited polyarteritis (5/9) and pulmonary renal syndrome (1/2). It fell to low or undetectable levels on clinical improvement or remission with cyclophosphamide therapy. Its detection was helpful in diagnosis and management of vasculitides with renal and extrarenal manifestations.

Adolescent↗
PubMed1993

Inherited structural and quantitative polymorphisms of C3b receptor (CR1) in normals and patients with glomerular diseases.

The erythrocyte C3b receptor (CR1) has been studied for its structural and quantitative polymorphisms in normal Indian individuals and in patients with glomerular diseases. In the normal Indian population, purification of CR1 by immunoprecipitation or C3b-Sepharose affinity column and subjecting it to electrophoresis showed the existence of two types of structural polymorphic patterns with M(r) of 190 kDa and 220 kDa, and with gene frequencies of 0.975 and 0.025, respectively. The gene frequencies of these alleles remain unaltered in the patient population. Evaluation of CR1 levels in the normal Indian population revealed a trimodal distribution of CR1 number suggesting a co-dominant allelic pattern (L and H alleles) for the quantitative expression of CR1 with gene frequencies of 0.523 and 0.477, respectively. In our earlier study we have shown that there is a decreased expression of CR1 on the erythrocytes of patients with acute glomerulonephritis. Since this decrease in the CR1 level in patients is an acquired characteristic, it may not be the level controlled by the LL homozygous alleles. The discrepancy in the gene frequencies of the structural and quantitative polymorphic alleles in normal individuals show that they are not linked to each other. In our earlier study, we showed that the affinity constant of C3b-CR1 binding in different individuals remains the same irrespective of the number of CR1 on the erythrocyte surface. Comparison of this result with the present investigation shows that there is no functional difference among various structural polymorphic forms of CR1 and the susceptibility to glomerular diseases is not associated with any of the CR1 polymorphic patterns.

Acute Disease↗
PubMed1993

Spectrum of poisoning requiring haemodialysis in a tertiary care hospital in India.

We report our experience in 66 cases of acute poisoning requiring haemodialysis (HD) in the last 17 years. Barbiturate poisoning was the commonest poisoning (30 cases). Mean blood barbiturate level was 8.9 mg%. Twenty four were in grade IV coma at the time of presentation. Twenty five required one HD and 5 cases needed 2 HD. Four died due to respiratory infection or hypotension. Copper sulphate poisoning was encountered in 19 cases. Common features in this group were: acute renal failure (ARF) (19), haematuria (3), gastrointestinal bleeding (7), intravascular haemolysis (9), jaundice (11), hepatocellular toxicity (8), methaemoglobinuria (8) and circulatory collapse (5). The indication for HD in all these cases was ARF. Seven patients died. There were 9 cases of mercuric chloride poisoning requiring 2-5 HD. Common features in this group were; ARF (9), gastrointestinal bleeding (9), anaemia (8), jaundice (2). Two patients died. Other patients had Mandrax, Naphthalene, Tincture Iodine, Ethylene Bromide and Lithium poisoning. Overall mortality in our study was 24.2%. It is concluded that HD is not the primary mode of therapy for drug intoxication. Adequate supportive management is most important in determining final outcome of these patients.

Barbiturates↗