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Biomedical subjects

S Sengupta

Publications and source records attributed to S Sengupta.

At least 37 records · Page 2Linked to original sources
PubMed2001

Argon plasma coagulation is an effective treatment for refractory hemorrhagic radiation proctitis.

INTRODUCTION: Chronic radiation proctitis complicating pelvic radiotherapy can be debilitating. It commonly presents with rectal bleeding, which can be difficult to control. Medical management of hemorrhagic radiation proctitis is not very successful, although surgery carries high risks. Thus, endoscopic treatments are preferred. The aim of this study is to assess the efficacy of argon plasma coagulation applied endoscopically to treat hemorrhagic radiation proctitis that has been refractory to topical formalin therapy. METHODS: Twelve patients who had ongoing bleeding from radiation proctitis, after previously failed formalin therapy, underwent endoscopic treatment using argon plasma coagulation. The efficacy of treatment was assessed by grading the frequency and severity of bleeding (0-4, 0 being no bleeding), hemoglobin level, and transfusion requirements. RESULTS: At a median follow-up of 11 months, ten patients (83 percent) had a significant reduction in the severity and frequency of bleeding, with complete cessation in six (50 percent). The presence of coexistent radiation-induced sigmoiditis in two patients was associated with reduced but persistent bleeding, because of difficulty in targeting the bleeding sites in the sigmoid colon. The median number of treatment sessions per patient was two (range, 1-3), with the number of sessions correlated with the extent of the proctitis. All patients had an improvement in their hemoglobin level, with the mean increasing from 11.2 to 12.3 g/dl. In the six months before starting therapy, all patients had been taking iron supplements, and four had required blood transfusions (median 3 units, range, 2-6). Iron supplements were ceased four weeks after the completion of therapy in all cases, and no further transfusions were required during the study period. None of the patients experienced any significant side effects or complications. CONCLUSIONS: Argon plasma coagulation is an effective and safe treatment for hemorrhagic radiation proctitis that has been refractory to topical formalin therapy.

Aged↗
PubMed2001

Local excision of rectal cancer: what is the evidence?

PURPOSE: Although local excision of rectal cancers is a less morbid alternative to radical resection, its role as a curative procedure is unclear. The role of adjuvant therapy after local excision is also controversial. This review aims to examine current evidence on local excision of rectal cancers and how it fits into the management algorithm for rectal cancer. METHODS: A literature review was undertaken through the MEDLINE database and by cross-referencing previous publications, thus identifying 41 studies on curative local excision of rectal cancer published in English. Details of preoperative staging, surgical procedures, adjuvant therapy, follow-up, and outcome measures, including complications, survival data, recurrences, and salvage were examined. RESULTS: Preoperative staging of rectal cancers is variable. Digital rectal examination and computerized tomography are used in most studies. Endorectal ultrasound is used in some patients in 9 of 41 studies. Local excision preserves anorectal function, and seems to have limited morbidity (0-22 percent). Local excision alone is associated with local recurrences in 9.7 (range, 0-24) percent of T1, 25 (range, 0-67) percent of T2 and 38 (range, 0-100) percent of T3 cancers. The addition of adjuvant chemoradiotherapy after local excision yields local recurrence rates of 9.5 (range, 0-50) percent for T1, 13.6 (range, 0-24) percent for T2, and 13.8 (range, 0-50) percent for T3 cancers. Data on local excision after preoperative chemoradiotherapy for tumor down staging are limited. Factors other than T-stage that lead to higher local recurrence rates after local excision include poor histologic grade, the presence of lymphovascular invasion, and positive margins. Local recurrences after local excision can be surgically salvaged (84 of 114 patients in 15 studies), with a disease-free survival rates between 40 and 100 percent at a follow-up of 0.1 to 13.5 years. CONCLUSIONS: Local excision for rectal cancers is associated with a low morbidity and provides satisfactory local control and disease-free survival rates for T1 rectal cancers. There is, however, a need for a randomized, controlled trial for T2 cancers, comparing local excision with adjuvant chemoradiotherapy to radical resection.

Algorithms↗
PubMed2001

Dietary fiber and colorectal neoplasia.

PURPOSE: Dietary fiber has been implicated in colorectal neoplasia, despite conflicting evidence. This is a review of the currently available data on the role of dietary fiber in colorectal carcinogenesis. METHODS: A literature search was conducted using the MEDLINE database. All case-control, longitudinal, and randomized, controlled studies published in English between 1988 and 2000 were identified, as were animal model studies in the period 1986 to 2000. Data from the various studies were tabulated and systematically analyzed, with particular emphasis on the effect of dietary fiber on tumor incidence and luminal parameters such as short chain fatty acids. RESULTS: Epidemiologic correlation studies show a high intake of dietary fiber to be associated with a lower risk of colorectal neoplasia. Thirteen of the 24 case-control studies reviewed demonstrated a protective effect of dietary fiber against colorectal neoplasia, and 16 showed a protective effect of vegetables or vegetable fiber. On the other hand, of 13 longitudinal studies in various cohorts, only 3 demonstrated a protective effect of fiber and 4 a protective effect of vegetables or vegetable fiber. The five published randomized, controlled trials all investigated the effect of increased fiber intake on short-term adenoma recurrence; however, none showed any significant protective effect. Among 19 experimental studies in animal models, 15 showed a protective effect of fiber against tumor induction compared with controls. Animal studies also showed that poorly fermentable fibers (e.g., wheat bran and cellulose) were more protective than soluble fibers (e.g., guar gum and oat bran), which sometimes enhanced carcinogenesis. No clear correlation was found between luminal pH or short chain fatty acids and tumor induction. CONCLUSIONS: On the basis of current data, there is little evidence to support the use of dietary fiber supplements to reduce the risk of colorectal neoplasia. Lifelong and early exposure may be important but are difficult to study. Other risk factors interact with the effects of dietary fiber.

Animals↗
PubMed2001

Acinetobacter baumannii--an emerging nosocomial pathogen in the burns unit Manipal, India.

A retrospective study on 113 patients admitted to the burns unit over a period of 12 months was undertaken to investigate the emerging trend of Acinetobacter baumannii infection. Wound infection with A. baumannii was seen in 13 (11.5%) patients. Of these six (46%) patients developed septicaemia with the same bacteria and five (38%) expired. The virulence of these bacteria, drug susceptibility pattern and its role as a nosocomial pathogen is discussed.

Acinetobacter↗
PubMed2001

Use of a computer-controlled bipolar diathermy system in radical prostatectomies and other open urological surgery.

BACKGROUND: Ligasure is a computer-controlled bipolar diathermy system, designed to optimally seal vessels < or = 7 mm in diameter. The aim of the present study was to evaluate its application to open urological surgery. METHODS: The Ligasure device was used in 32 consecutive open surgical cases, including 25 radical prostatectomies, five radical nephrectomies, one partial nephrectomy and one nephro-ureterectomy. All procedures were performed using standard surgical techniques, with the exception that the Ligasure device was used for haemostasis. This included pelvic lymphatics and prostatic, adrenal, gonadal and aberrant obturator vessels, as well as vessels associated with the ureter, vasa, seminal vesicles, peri-renal fat, peritoneum and peri-adrenal tissues. Vessels > 7 mm in diameter, such as the renal artery, were ligated. In no patients were haemostatic clips used. RESULTS: In all procedures, vessels and other structures < 7 mm were successfully sealed using the Ligasure device. For some structures, such as the prostatic pedicles and the seminal vesicles, the Ligasure device was much easier to apply than haemostatic clips. Use of the Ligasure device reduced the operating time (mean: 113 min vs 135.5 min; P < 0.001) and blood loss (mean: 529 mL vs 642 mL; P < 0.02) for radical prostatectomies. No intraoperative or postoperative blood transfusions were required. There were no postoperative haemorrhages, lymph leakage or lymphocoeles. Median inpatient hospital stay was 7 days (range: 6-9 days) and no patients required readmission. CONCLUSION: The Ligasure, device was safe and easy to use in major urological procedures.

Aged↗
PubMed2001

Prediction of pancreatitis following endoscopic retrograde cholangiopancreatography by the 4-h post procedure amylase level.

BACKGROUND: Pancreatitis is the commonest and most significant complication of endoscopic retrograde cholangiopancreatography (ERCP). Early detection of post-ERCP pancreatitis would allow the safe discharge of day-case patients and targeted use of preventive therapies. Clinical diagnosis is inaccurate, and the aim of this study was to evaluate the 4-h post-ERCP hyperamylasemia as a predictor of pancreatitis. METHODS: Two hundred and sixty-three consecutive ERCPs performed at one center were prospectively analyzed, examining patient and procedure characteristics, as well as the amylase level as predictors of pancreatitis. RESULTS: Younger age (< 25 years), Sphincter of Oddi dysfunction, pancreatogram and failed cannulation were risk factors for pancreatitis; sphincterotomy conferred an increased risk, which was not statistically significant. Hyperamylasemia was a highly sensitive and moderately specific predictor of pancreatitis. A cut-off level of 1.5-fold higher than normal was useful for the exclusion of pancreatitis, while a cut-off level of threefold higher than normal was more specific, so as to target potential preventive therapies. CONCLUSIONS: The 4-h post-ERCP amylase level is a useful test to base management decisions on. It needs to be interpreted in conjunction with clinical assessment as well as identifiable risk factors related to the patient or the procedure.

Adolescent↗
PubMed2001

Uropathogenic Escherichia coli potentiates type 1 pilus-induced apoptosis by suppressing NF-kappaB.

Urinary tract infections (UTIs) are among the most common inflammatory diseases. Acute UTIs are typically caused by type 1-piliated Escherichia coli and result in urothelial apoptosis, local cytokine release, and neutrophil infiltration. To examine the urothelial apoptotic response, a human urothelial cell line was incubated with various E. coli isolates and was then characterized by flow cytometry. Uropathogenic E. coli (UPEC) induced rapid urothelial apoptosis that was strictly dependent upon interactions mediated by type 1 pili. Interestingly, nonpathogenic HB101 E. coli expressing type 1 pili induced apoptosis at approximately 50% of the level induced by UPEC, suggesting that pathogenic strains contribute to apoptosis by pilus-independent mechanisms. Consistent with this possibility, UPEC blocked activity of an NF-kappaB-dependent reporter in response to inflammatory stimuli, yet this effect was independent of functional type 1 pili and was not mediated by laboratory strains of E. coli. UPEC suppressed NF-kappaB by stabilizing IkappaBalpha, and UPEC rapidly altered cellular signaling pathways. Finally, blocking NF-kappaB activity increased the level of piliated HB101-induced apoptosis to the level of apoptosis induced by UPEC. These results suggest that UPEC blocks NF-kappaB and thereby enhances type 1 pili-induced apoptosis as a component of the uropathogenic program.

Apoptosis↗
PubMed2001

Encapsulation in cationic liposomes enhances antitumour efficacy and reduces the toxicity of etoposide, a topo-isomerase II inhibitor.

Etoposide exerts its antineoplastic effect by forming a ternary complex with topo-isomerase II and DNA, leading to DNA breaks and cell death. However, it causes myelosuppression and its lipophilicity poses a major limitation during administration. Liposomes have been reported to increase the efficacy and reduce the toxicity of antineoplastic agents. Recent evidence suggests that cationic liposomes bind efficiently to tumours. The present study was thus designed to encapsulate etoposide in cationic liposomes and to evaluate its antitumour efficacy and systemic toxicity in comparison with a conventional parenteral formulation. Etoposide encapsulated in liposomes was synthesised by thin film hydration followed by an extrusion method. Fibrosarcoma was induced in mice by subcutaneous administration of 20-methylcholanthrene. Chemotherapy was started when the tumour reached 200 mm(3) in volume. Liposomal etoposide (10 mg/m(2)/day for 5 days) significantly delayed tumour growth as compared to non-liposomal etoposide. The median time of death was calculated to be 19.5, 26.25 and 56 days in vehicle-treated controls, non-liposomal-etoposide- and liposomal-etoposide-treated groups, respectively. A transient reduction in body weight was seen in both the liposomal- and non-liposomal-etoposide-treated groups. The maximum tolerated dose was however significantly higher in the group treated with liposomal etoposide, which also exhibited a lesser degree of myelosuppression than the animals treated with non-liposomal etoposide. The present findings suggest that cationic liposomes could be considered as potential for delivery of etoposide to tumours.

Animals↗
PubMed2001

Idiopathic bilateral external jugular vein thrombosis--a case report.

The authors report a patient with the rare presentation of bilateral external jugular vein thrombosis. A 45-year-old man presented with swelling over both sides of the neck and puffiness of the face. Physical examination revealed cordlike thickening of both the external jugular veins. Two-dimensional echocardiographic and Doppler studies showed thrombosis of both the external jugular veins and digital subtraction angiography (DSA) revealed nonvisualization of external jugular veins of either side. No malignancy, coagulation disorder, or any infection was demonstrable. A regular follow-up for 1 year was done, but no other cause could be found and there was no progression of the disease.

Angiography, Digital Subtraction↗
PubMed2001

The role of community advisory boards: involving communities in the informed consent process.

Ethical research involving human subjects mandates that individual informed consent be obtained from research participants or from surrogates when participants are not able to consent for themselves. The existing requirements for informed consent assume that all study participants have personal autonomy; fully comprehend the purpose, risks, and benefits of the research; and volunteer for projects that disclose all relevant information. Yet contemporary examples of lapses in the individual informed consent process have been reported. The authors propose the use of community advisory boards, which can facilitate research by providing advice about the informed consent process and the design and implementation of research protocols. These activities could help reduce the number of individual informed consent lapses, benefiting study participants and the scientific integrity of the research in question.

Advisory Committees↗
PubMed2001

Making grandma's data secure: a security architecture for home telemedicine.

Home telemedicine presents special challenges for data security and privacy. Experience in the Informatics for Diabetes Education And Telemedicine (IDEATel) project has demonstrated that data security is not a one-size-fits-all problem. The IDEATel users include elderly patients in their homes, nurse case managers, physicians, and researchers. The project supports multiple computer systems that require a variety of user interactions, including: data entry, data review, patient education, videoconferencing, and electronic monitoring. To meet these various needs, a number of different of security solutions were utilized, including: UserID/Password, PKI certificates, time-based tokens, IP filtering, VPNs, symmetric and asymmetric encryption schemes, firewalls and dedicated connections. These were combined in different ways to meet the needs of each user groups.

Aged↗
PubMed2001

Role of alphavbeta3 integrin receptors in breast tumor.

The intriguing problem of tumor metastasis involves adhesion of the metastatic cells via the integrin group of cell surface receptors to the ECM proteins of the basement membrane. Modulation of integrin family of cell surface receptors is believed to be associated with stages of tumor metastasis. In this present study, results obtained indicate that alphavbeta3 vitronectin receptors may play an important role in the malignant behaviour of human breast tumor. Alphavbeta3 integrin receptors can modulate the activity of collagenase enzyme and thereby the invasive property of breast tumor cells.

Breast Neoplasms↗
PubMed2001

Food and feeding of Amphiesma stolatum (Linnaeus 1758).

The food and feeding behaviour of Amphiesma stolatum was studied. A total of 117 snakes were examined to analyse the diet composition. Ten live snakes were maintained in enclosure for evaluating the feeding habit, choice of food and rate of assimilation. The anurans constituted the major diet of the food spectrum. In captivity, fishes (fry), amphibians and reptiles were consumed by the snakes. A. stolatum exihibited Elaphe type of hunting behaviour. In most cases the snake struck the prey at its head. The assimilation rate with frog was highest.

Amphibians↗
PubMed2000

Ethical issues in early detection of HIV infection to reduce vertical transmission.

Proposals to make prenatal HIV testing routine and universal dramatize ethical issues regarding early detection of HIV. These proposals would abolish pretest counseling and written informed consent for prenatal HIV testing. Ethical concerns include whether pregnant women are adequately informed that they may refuse such testing and whether patients have an opportunity to obtain more detailed information about the benefits and risks of HIV testing in this context. Several pertinent research questions need to be studied, including whether pregnant women find routine universal HIV testing acceptable and whether safeguards adequately protect women who receive testing. If analogous policies to enhance early detection of HIV are considered in other clinical contexts, the important clinical and ethical differences between vertical transmission and other situations of HIV transmission must be kept clearly in mind.

Breast Feeding↗
PubMed2000

Negative cross-talk between p53 and the glucocorticoid receptor and its role in neuroblastoma cells.

The tumour suppressor p53 and the glucocorticoid receptor (GR) respond to different types of stress. We found that dexamethasone-activated endogenous and exogenous GR inhibit p53-dependent functions, including transactivation, up- (Bax and p21(WAF1/CIP1)) and down- (Bcl2) regulation of endogenous genes, cell cycle arrest and apoptosis. GR forms a complex with p53 in vivo, resulting in cytoplasmic sequestration of both p53 and GR. In neuroblastoma (NB) cells, cytoplasmic retention and inactivation of wild-type p53 involves GR. p53 and GR form a complex that is dissociated by GR antagonists, resulting in accumulation of p53 in the nucleus, activation of p53-responsive genes, growth arrest and apoptosis. These results suggest that molecules that efficiently disrupt GR-p53 interactions would have a therapeutic potential for the treatment of neuroblastoma and perhaps other diseases in which p53 is sequestered by GR.

Apoptosis↗
PubMed2000

Mechanisms for the formation of protein-bound homocysteine in human plasma.

Hyperhomocysteinemia is an independent risk factor for cardiovascular disease. Greater than 70% of homocysteine in circulation is protein-bound. An in vitro model system using human plasma has been developed to study mechanisms of protein-bound homocysteine formation and establish the equilibrium binding capacities of plasma for homocysteine. Addition of homocysteine to plasma caused an initial rapid displacement of cysteine and a subsequent increase in protein-bound homocysteine. This rapid reaction was followed by a slower oxygen-dependent reaction forming additional protein-bound homocysteine. To determine the equilibrium binding capacity of plasma proteins for homocysteine, plasma was treated with 0.5-10 mM dl-homocysteine for 4 h at 37 degrees C under aerobic conditions. Under these conditions the equilibrium binding capacity was 4.88 +/- 0.51 and 4.74 +/- 0.68 micromol/g protein for male (n = 10) and female (n = 10) donors, respectively. The mechanism of protein-bound homocysteine formation involves both thiol-disulfide exchange and thiol oxidation reactions. We conclude that plasma proteins have a high capacity for binding homocysteine in vitro.

Blood Proteins↗
PubMed2000

Differential effects of C-terminal molecular tagged integrase on replication competent moloney murine leukemia virus.

Moloney murine leukemia virus (M-MuLV) proviruses carrying integrase (IN) protein tagged either with a simian virus 40 (SV40) nuclear localization signal (NLS) or various antigenic epitopes were generated. Hexahistidine (His(6)), hemagluttinin (HA), or two consecutive HA sequences (2XHA) were fused to the C-terminus of IN as antigenic markers. These epitope-tagged IN proteins were stably expressed through multiple rounds of infection. The IN-His(6), IN-HA, and IN-2XHA proteins, purified from virus, could be immunoprecipitated with antibodies against His(6) and HA, respectively. An M-MuLV provirus encoding the SV40 large T antigen NLS fused to IN at the same position as the epitope tags was also passaged through cells. In contrast to the stability of the epitope tags, the SV40 NLS sequence was rapidly mutated by a frameshift mutation that introduced negatively charged amino acids into the basic NLS. The instability of the NLS suggests that the strong nuclear localization of the IN-SV40 NLS may have detrimental effects on virus assembly. These observations have implications for studying nuclear transport properties of M-MuLV and for engineering a murine-based retroviral vector for gene therapy.

Amino Acid Sequence↗