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Biomedical subjects

M Choudhury

Publications and source records attributed to M Choudhury.

At least 37 records · Page 2Linked to original sources
PubMed1996

Quantitative measurement of heme oxygenase-1 in the human renal adenocarcinoma.

Heme oxygenase (HO-1) is the rate-limiting enzyme in heme catabolism. HO-1, a stress protein, has been suggested to be involved in defense mechanisms against agents that may induce oxidative stress. It has been proposed that renal HO gene expression regulates important hemoprotein(s) such as cytochrome P450 and may be essential to maintain homeostasis in the kidney. Because accurate assessment of HO-1 mRNA in normal and disease states in kidney were not available due to the limited number of cells, we developed a system to quantitate human HO-1 mRNA in samples limited in cell number and/or mRNA copies. Total RNA from human kidney was used to establish this technique; it was reverse-transcribed and then amplified by polymerase chain reaction (PCR) in a tube also containing an internal standard obtained by deleting 50 bp from the original human HO-1 gene. This allowed us to use the same primers for both the sample and internal standard. After amplification, templates were resolved by acrylamide gel electrophoresis and quantitated either by densitometry or radioactivity counted from the bands excised from the gel. When the internal standard is present in the reaction mixture, the ratio of amplified sample vs. the standard template is proportional to the amount of sample RNA, and it is therefore possible to calculate the number of specific mRNA molecules. We have used this approach to quantitate the number of HO-1 mRNA molecules in adenocarcinoma cells. Results show that reverse transcription (RT)/PCR methods were able to determine the number of HO-1 mRNA copies in biopsy samples of human adenocarcinoma cells.

Adenocarcinoma↗
PubMed1994

Effects of IFN-beta on growth of human prostatic JCA-1 cells.

Addition of IFN-beta resulted in a dose-dependent reduction of growth, a drop in [3H]thymidine incorporation into DNA, and a concurrent 69% and 15% increase in the S and G2/M phases, of the human prostatic JCA-1 cells. No correlation existed between the antimitogenicity of IFN and increases in the double-stranded RNA-dependent protein kinase activity. Although IFN elicited a large increase in 2-5A synthetase activity, activation of the 2-5A-dependent RNase L could not be demonstrated in JCA-1 cells rendered permeable to 2-5A, implying that the 2-5A pathway is not involved in the anti-proliferative effects of IFN. Analysis of endogenous proteins phosphorylated in vitro show that some IFN-inducible phosphoproteins were dependent upon the presence of double-stranded DNA.

2',5'-Oligoadenylate Synthetase↗
PubMed1994

Vitamin A deficiency in children with acute diarrhoea.

Ninety-five children between 9 months and 3 years (mean age 14.4 months) with acute diarrhoea were enrolled by simple random sampling and studied for the presence of xerophthalmia and subclinical vitamin-A deficiency (detected by ocular impression cytology). The objective of the study was to estimate the prevalence of vitamin-A deficiency in these children and to evaluate its role as a risk factor for acute diarrhoea. The results were compared with 96 sex-and age-matched (mean age 15.79 months) controls belonging to similar nutritional grades and socioeconomic status who did not have diarrhoea and attended the hospital for treatment of minor ailments or for immunizations. Clinically evident xerophthalmia was observed in 12.6% of cases with acute diarrhoea and in 10.4% of controls. Ocular impression cytology suggested vitamin-A deficiency in 48.4% of cases and 40.6% of controls. However, on comparing the study group with the controls, there was no significant difference in vitamin-A deficiency in the 2 groups on clinical examination (p > 0.05) or by ocular impression cytology (p > 0.05). The prevalence rate of vitamin-A deficiency increased with the severity of malnutrition in cases (p < 0.05) as well as in controls (p < 0.05), but subclinical vitamin-A deficiency was detected even in well-nourished cases (35%) and controls (22.7%). Our results suggest a high prevalence of vitamin-A deficiency in young children from our study population with or without diarrhoea and even in well-nourished children. The association of vitamin-A deficiency was not significantly different in cases of acute diarrhoea than in the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1993

Interferons and interleukins in metastatic renal cell carcinoma.

Renal cell carcinoma is diagnosed frequently when it already has metastasized. The use of immunotherapy has provided a new source of drugs to be used in the therapy of renal cell carcinoma. Interferons were the first biologics to be evaluated demonstrating a response rate of 10-30 percent. The second cytokine to be actively developed was interleukin-2, a T-cell growth factor which demonstrated activity in patients with renal cell carcinoma of 20-30 percent alone or in combination with LAK cells and other cytokines (such as interferons and tumor necrosis factor). Biologic response modifiers such as interferons and interleukins alone and in combination with other drugs have opened a new era in the therapy of renal cell carcinoma. Future development of other cytokines may pave the way for higher response rates with durable duration for this disease.

Carcinoma, Renal Cell↗
PubMed1993

Carcinoma in female urethral diverticulum: case reports and review of management.

We report on 4 women ages 31 to 65 years with adenocarcinoma of urethral diverticulum. One patient presented with metastatic disease and died after refusing post-radiation surgery. The other 3 women were without evidence of disease 9 to 44 months after diverticulectomy with radiation (1) or radical surgery (2). Review of our 4 cases and 64 cases documented in the literature showed that irritative voiding symptoms and hematuria were the most common findings. A palpable urethral mass was described in only 56% of reported cases but was observed in all of our patients, with the smallest mass measuring 2 x 2 cm. Urethroscopy with biopsy is the most important diagnostic test. Aggressive treatment is appropriate in most patients, since local recurrence has been documented in 44% of those treated by diverticulectomy and/or radiation.

Adenocarcinoma↗
PubMed1993

Altered T and B lymphocytes in multitransfused patients of thalassemia major.

T and B lymphocytes were estimated in 25 patients with Thalassemia major to evaluate their immune status. The percentage of T cells was significantly reduced (p < 0.001) while that of B cells was significantly raised (p < 0.001) in patients of thalassemia major as compared to age and sex matched controls.

B-Lymphocytes↗
PubMed1992

Unusual primary prostatic malignancies.

Atypical prostatic cancer is defined as any malignancy of prostatic origin, excluding the common acinar prostatic adenocarcinoma. These atypical prostate cancers account for less than 5 percent of all prostatic malignancies. Because atypical prostatic malignancies occur rarely, little is known about their biologic behavior. To date, no large series of patients have been reported, and specific treatment protocols have yet to be defined. Herein we describe 5 new cases of atypical prostatic cancer. By reporting the occurrence of new cases, we believe a better understanding of the natural history of these lesions will emerge.

Adenocarcinoma, Mucinous↗
PubMed1991

A "Pap" test for men? Male urethral smears as screening tool for detecting subclinical human papillomavirus infection.

We have explored the potential of using immunoperoxidase staining and in situ DNA hybridization techniques to detect the HPV common antigen and HPV DNA (subtypes 6/11 and 16/18) in urethral smears obtained from men with no grossly visible urethral lesions, with or without HPV-related clinical history. A total of 91 such smears were studied of which 25 (27.5%) were positive for HPV antigen. Of the latter, 20 (80%) were positive for HPV 6/11 DNA, 3 (12%) were positive for HPV 16/18 DNA, one smear (4%) was positive for both, and one was negative for both. The technique of obtaining male urethral smears and immunostaining them for HPV antigen is simple, rapid, specific, and far more sensitive than conventional morphologic observations. Since antigen-positive cells are the source for spreading HPV infection, identifying individuals with such cells can help limit the spread of infection by alerting sexual partners, and also can be used to monitor the infectious status of the patient after therapy. DNA subtyping of HPV-positive patients may be useful in predicting the potential for malignant transformation which varies among the different HPV subtypes.

Antigens, Viral↗
PubMed1990

Benign soft-tissue neoplasm simulating sarcoma of spermatic cord.

A large, painless, slow-growing mass arising in the scrotum of a twenty-three-year-old man, which proved to be benign myxoma, simulated a primary sarcoma of the spermatic cord. Only 1 case of myxoma involving the spermatic cord has been reported previously. It is extremely important that multiple microscopic sections of the specimen be examined carefully so that the proper tissue diagnosis can be made. A false diagnosis of malignancy may lead to treatment that is not indicated and that has a high morbidity.

Adult↗
PubMed1990

Adaptive myocardial hypertrophy in the renal ablation model.

We have previously reported downregulation of the vascular alpha 1-receptor in the 5/6 renal ablation model. In this investigation we have examined the adaptive response of the heart following 5/6 renal ablation. Renal ablated and sham rats were maintained under identical conditions for 6 weeks. Despite the presence of systemic hypertension in renal ablated rats (185 +/- 10 mm Hg, P less than .01), heart weight did not differ from sham. [125I] +/- CYP binding was performed and myocardial norepinephrine (NE) content determined to evaluate myocardial sympathetic neuroeffector mechanisms. Scatchard analysis and 1-isoproterenol competition curves did not reveal a difference in the binding properties of the myocardial beta-receptor. No difference in myocardial NE was found in renal ablated and sham rats. Unexpectedly, 1-isoproterenol stimulation of adenylate cyclase was impaired in renal ablated rats (32.6 +/- 6 v 58.6 +/- 5 pmol/mg/min, P less than .01) and the dose response curve shifted to the right. We conclude that despite systemic hypertension an adaptive hypertrophic response was not present in hearts of renal ablated rats; myocardial sympathetic neuroeffector mechanisms are not altered in this model; and impaired stimulation of adenylate cyclase appears to be the result of a post-receptor defect.

Adaptation, Physiological↗
PubMed1989

Pseudodiverticulum of the bladder: an unusual complication of pelvic trauma.

Investigation of frequent urinary tract infections 2 months after an accident in which a man sustained pelvic fractures and a head injury revealed a large pseudodiverticulum between the left bladder wall and pelvis, and extending inferiorly and medially through the separated symphysis pubis into the upper left thigh.

Adult↗
PubMed1988

Value of proximal diversion and ureteral stenting in management of penetrating ureteral trauma.

Cases of penetrating ureteral trauma (17 gunshot wounds and 4 stab wounds) seen at two New York City hospitals over a nine-year period were reviewed. Early urologic complications (defined as urine drainage from the wound for greater than 2 weeks or need for a second operation) occurred in 50 percent of patients with a proximal ureteral injury but were less common when a nephrostomy and stent were used in the repair. A similar beneficial effect of stenting was seen in published cases, with a 91 percent complication rate for unstented repairs and a 15 percent rate when stenting and nephrostomy drainage were both used. The effect of stenting on midureteral repairs was less obvious, but the rate of urologic complications was lower in stented cases. None of the patients with distal ureteral injuries suffered a urologic complication. Stenting with and without a nephrostomy tube also produced good results in 2 patients with proximal ureteral injuries diagnosed late. We conclude that repair of penetrating ureteral injuries should include stenting and nephrostomy tube drainage in cases of proximal injuries, as well as generous debridement and water-tight closure. Midureteral injuries accompanied by gastrointestinal, pancreatic, and major vascular injuries should be stented and proximal diversion considered when prosthetic materials are used for vascular repairs.

Adolescent↗
PubMed1988

Fibroepithelial polyp associated with congenital ureteral diverticulum: report of 2 cases.

We report 2 cases of a single fibroepithelial polyp in conjunction with ureteral diverticula. Ureterorenoscopy is valuable in the identification of the benign nature of these lesions preoperatively to avert unnecessary nephroureterectomy. The etiology of fibroepithelial polyps remains unknown, although many theories have been proposed. Recent evidence has suggested that these lesions may be a developmental anomaly. Congenital ureteral diverticula also are thought to be of developmental origin. We hypothesize that fibroepithelial polyps and congenital diverticula of the ureter are part of a spectrum of the same developmental anomaly.

Adult↗