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Biomedical subjects

S Ghosh

Publications and source records attributed to S Ghosh.

At least 73 records · Page 4Linked to original sources
PubMed2005

Comparison of apoptosis and mortality measurements in peripheral blood mononuclear cells (PBMCs) using multiple methods.

Death through apoptosis is the main process by which aged cells that have lost their function are eliminated. Apoptotic cells are usually detected microscopically by changes in their morphology. However, determination of early apoptotic events is important for in vitro (and ex vivo) studies. The main objective of the present study is to find the most sensitive method for apoptosis detection in human peripheral blood mononuclear cells (PBMCs) by comparing six different methods following five different means of immunological stimulation at 3 and 5 days. Each of six apoptosis quantification methods, except the trypan blue exclusion test, is a combination of two stains, one for the specific detection of apoptotic cells and the other for the unspecific detection of dead cells. Values for apoptosis and mortality were compared with a reference method. The choice of apoptosis detection method is more important following 3 days of stimulation than after 5 days of stimulation (P=2x10(-6) versus P=1x10(-2)). In contrast, we find mortality measurements following the different means of stimulation highly significant at both 3 and 5 days (F2.28=7.9, P=1.4x10(-6) at 3 days and F2.28=8.5, P=4.5x10(-7) at 5 days). Variation as a result of the combination of specific PBMC stimulation and the method used to detect apoptosis is reduced considerably with time (F1.58+3.7, P+3x10(-7) at 3 days to F=1.58=0.97, P=0.5 at 5 days). Based on Tukey's test, YO-PRO-1 is the most sensitive stain for apoptosis and, when combined with 7-AAD, provides an accurate measure of apoptosis and mortality. In conclusion, we propose YO-PRO-1/7-AAD as a new combination and low-cost alternative for the sensitive detection of early apoptosis.

Antibodies↗
PubMed2005

Measuring EGJ opening patterns using high resolution intraluminal impedance.

The aim of this study was to adapt impedance methodology to study esophagogastric junction (EGJ) sphincter opening and compare opening patterns of the EGJ during deglutitive LES relaxation (dLESR) and transient LES relaxation (tLESR). We studied eight healthy subjects with a novel 12-lumen combined impedance/manometry catheter, the main element of which was a 6 cm sleeve sensor with six side hole sensors and six impedance rings spaced at 1 cm increments along its length. Subjects underwent an air infusion protocol after standard assessment and data tracings and isocontour plots were analysed to assess opening characteristics of the EGJ during dLESRs and tLESRs. Our results revealed that during dLESR the opening pattern was top to bottom, occurred in 0-2.7 s and in 29 of 35 (83%) cases the leading edge of the bolus was liquid. Opening during tLESR began between -7.8 and +8.6 s relative to the onset of nadir LES relaxation. The opening pattern during tLESR was bottom to top, occurred in 0-7.7 s, and in 22 of 29 (76%) the leading edge was liquid. These results support that impedance monitoring can be adapted to identify sphincter opening, to distinguish sphincter opening from sphincter relaxation, and to determine luminal contents during the opening period.

Adult↗
PubMed2005

Peroxisome proliferator-activated receptor-gamma co-activator-1alpha (PGC-1alpha) gene polymorphisms and their relationship to Type 2 diabetes in Asian Indians.

AIMS: The objective of the present investigation was to examine the relationship of three polymorphisms, Thr394Thr, Gly482Ser and +A2962G, of the peroxisome proliferator activated receptor-gamma co-activator-1 alpha (PGC-1alpha) gene with Type 2 diabetes in Asian Indians. METHODS: The study group comprised 515 Type 2 diabetic and 882 normal glucose tolerant subjects chosen from the Chennai Urban Rural Epidemiology Study, an ongoing population-based study in southern India. The three polymorphisms were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Haplotype frequencies were estimated using an expectation-maximization (EM) algorithm. Linkage disequilibrium was estimated from the estimates of haplotypic frequencies. RESULTS: The three polymorphisms studied were not in linkage disequilibrium. With respect to the Thr394Thr polymorphism, 20% of the Type 2 diabetic patients (103/515) had the GA genotype compared with 12% of the normal glucose tolerance (NGT) subjects (108/882) (P = 0.0004). The frequency of the A allele was also higher in Type 2 diabetic subjects (0.11) compared with NGT subjects (0.07) (P = 0.002). Regression analysis revealed the odds ratio for Type 2 diabetes for the susceptible genotype (XA) to be 1.683 (95% confidence intervals: 1.264-2.241, P = 0.0004). Age adjusted glycated haemoglobin (P = 0.003), serum cholesterol (P = 0.001) and low-density lipoprotein (LDL) cholesterol (P = 0.001) levels and systolic blood pressure (P = 0.001) were higher in the NGT subjects with the XA genotype compared with GG genotype. There were no differences in genotype or allelic distribution between the Type 2 diabetic and NGT subjects with respect to the Gly482Ser and +A2962G polymorphisms. CONCLUSIONS: The A allele of Thr394Thr (G --> A) polymorphism of the PGC-1 gene is associated with Type 2 diabetes in Asian Indian subjects and the XA genotype confers 1.6 times higher risk for Type 2 diabetes compared with the GG genotype in this population.

Adult↗
PubMed2005

Reparative properties of a commercial fish protein hydrolysate preparation.

BACKGROUND: A partially hydrolysed and dried product of pacific whiting fish is currently marketed as a health food supplement to support "intestinal health". However, there has been only limited scientific study regarding its true biological activity. AIMS: We therefore tested its efficacy in a variety of models of epithelial injury and repair. METHODS: Effects on proliferation were determined using [(3)H] thymidine incorporation into epithelial rat intestinal RIE-1 and human colonic HT29 cells. Effects on restitution (cell migration) were analysed using wounded HT29 monolayers and its ability to influence gastric injury analysed using a rat indomethacin restraint model. Partial characterisation of bioactive agents was performed using mass spectroscopy, high pressure liquid chromatography, and gas chromatography. RESULTS: Both cell proliferation and cell migration were increased by about threefold when added at 1 mg/ml (p<0.01). Gastric injury was reduced by 59% when gavaged at 25 mg/ml (p<0.05), results similar to using the potent cytoprotective agent epidermal growth factor at 12.5 mug/ml. The vast majority of biological activity was soluble in ethanol, with glutamine in its single, di-, and tripeptide forms probably accounting for approximately 40% of the total bioactivity seen. Fatty acid constituents may also have contributed to cell migratory activity. CONCLUSIONS: Fish protein hydrolysate possesses biological activity when analysed in a variety of models of injury and repair and could provide a novel inexpensive approach for the prevention and treatment of the injurious effects of non-steroidal anti-inflammatory drugs and other ulcerative conditions of the bowel. Further studies appear justified.

Animals↗
PubMed2005

Zidovudine: a targeted therapy for endemic Burkitt's lymphoma.

BACKGROUND: Although cyclophosphamide based regimens can produce remission rates approaching 60 to 80% in endemic Burkitts lymphoma, relapses and refractory disease are fairly common in developing countries, due to advanced stage disease and cost-constraints in the implementation of optimal chemotherapeutic protocols. OBJECTIVE: To evaluate an affordable, tolerable and targeted approach to chemotherapy for endemic Burkitt's lymphoma as would be desirable in resource poor settings such as Africa. METHOD: We present data and review pertinent literature that indicates that the antiviral agent Zidovudine specifically targets this tumour through a unique and novel mechanism. DATA SOURCE: Our original studies, publications original and review articles searched in Pubmed indexed for Medline. DATA EXTRACTION: A systematic review to identify studies relating to Zidovudine, EBV+ and Burkitt's lymphoma, indicating antiviral agents zidovudine targeting BL in a unique and novel mechanisms. DATA SYNTHESIS: Our data and a qualitative assessment of the relevant literature was undertaken, given the heterogenicity of the study types making it inappropriate to pool results across studies. CONCLUSION: Our data suggests that the incorporation of Zidovudine into Burkitt's regimens may enhance tumour kill and abbreviate the duration of treatment necessary for this disease. Furthermore, the addition of the widely available and inexpensive agent hydroxyurea, markedly potentiates the tumorcidal activity of Zidovudine in Epstein Barr virus positive Burkitt's lymphomas. We recommend that further clinical studies in patients afflicted with this disease are needed to clearly define this potential use of Zidovudine.

Africa↗
PubMed2005

Comparative diagnostic potentiality of ELISA and dot-ELISA in prepatent diagnosis of experimental Fasciola gigantica infection in cattle.

A glycoprotein (27 kDa) was isolated from crude somatic antigen of Fasciola gigantica by two steps affinity chromatography and was used in early detection of experimental fasciolosis in cattle by indirect ELISA and in dot-ELISA formats. Although, anti-27 kDa antibodies could be detected after 3 weeks post infection (WPI) by dot - ELISA which was one week later than indirect ELISA. The test, dot-ELISA, was more convenient in field application. By the test (dot-ELISA) the infection could be equally detected in animals infected with 100, 200 and 300 metacercariae of F. gigantica with high sensitivity. Further, the antigen (27 kDa) was not found to react with goat sera infected with Paramphistomum epiclitum, which are giving strong reaction to homologous immature and mature fluke antigens of P. epiclitum.

Animals↗
PubMed2004

Ion dynamics in mixed alkali cadmium fluoride glasses.

We have investigated ion dynamics in cadmium fluoride nonoxide glasses, in the frequency range from 10 Hz to 2 MHz and in the temperature range from room temperature to just below the glass transition temperature. We have established the existence of mixed alkali effect for these glasses from different aspects of relaxation dynamics. We have observed lower dimensionality of the conduction pathways in mixed alkali cadmium fluoride glasses compared to that in the single alkali glasses. Although, both n and beta represent the interaction between the charge carriers, we have not found any theoretical correlation between them. Using different scaling approaches we have shown that the relaxation dynamics in mixed alkali cadmium fluoride glasses is independent of temperatures.

Journal Article↗
PubMed2004

Endoscopy: a must in neonatal respiratory distress.

Respiratory distress in a newborn presents both diagnostic and therapeutic dilemmas. Definitive treatment must be preceded by an accurate diagnosis other than in extremes. Complete tracheal rings are a very rare congenital cause of airway obstruction. Unlike other causes of upper airway obstruction, this cannot be relieved by tracheostomy, which may be counterproductive. We report the case of an 8-day-old female baby who presented with respiratory distress and was found to have complete tracheal rings and right pulmonary agenesis. The value of tracheo-bronchoscopy in this case cannot be overstressed.

Airway Obstruction↗
PubMed2004

Strength functions, entropies, and duality in weakly to strongly interacting fermionic systems.

We revisit statistical wave function properties of finite systems of interacting fermions in the light of strength functions and their participation ratio and information entropy. For weakly interacting fermions in a mean-field with random two-body interactions of increasing strength lambda, the strength functions F(k) (E) are well known to change, in the regime where level fluctuations follow Wigner's surmise, from Breit-Wigner to Gaussian form. We propose an ansatz for the function describing this transition which we use to investigate the participation ratio xi(2) and the information entropy S(info) during this crossover, thereby extending the known behavior valid in the Gaussian domain into much of the Breit-Wigner domain. Our method also allows us to derive the scaling law lambda(d) approximately 1/sqrt[m] ( m is number of fermions) for the duality point lambda= lambda(d), where F(k) (E), xi(2), and S(info) in both the weak ( lambda=0 ) and strong mixing ( lambda= infinity ) basis coincide. As an application, the ansatz function for strength functions is used in describing the Breit-Wigner to Gaussian transition seen in neutral atoms CeI to SmI with valence electrons changing from 4 to 8.

Journal Article↗
PubMed2004

Complete tracheal rings: lower airway symptoms can delay diagnosis.

Bronchial asthma is a very common condition seen in children diagnosed by clinical examination. While treating these children, all the other possible causes of breathlessness including complete tracheal rings should be considered. Further investigations in the form of endoscopy may need to be carried out in doubtful cases.

Airway Obstruction↗
PubMed2004

Human keratin 8 mutations that disturb filament assembly observed in inflammatory bowel disease patients.

We have identified miss-sense mutations in keratin 8 in a subset of patients with inflammatory bowel disease (Crohn disease and ulcerative colitis). Inflammatory bowel diseases are a group of disorders that are polygenic in origin and involve intestinal epithelial breakdown. We investigated the possibility that these keratin mutations might contribute to the course of the disease by adversely affecting the keratin filament network that provides mechanical support to cells in epithelia. The mutations (Gly62 to Cys, Ile63 to Val and Lys464 to Asn) all lie outside the major mutation hotspots associated with severe disease in epidermal keratins, but using a combination of in vitro and cell culture assays we show that they all have detrimental effects on K8/K18 filament assembly in vitro and in cultured cells. The G62C mutation also gives rise to homodimer formation on oxidative stress to cultured intestinal epithelial cells, and homodimers are known to be polymerization incompetent. Impaired keratin assembly resulting from the K8 mutations found in some inflammatory bowel disease patients would be predicted to affect the maintenance and re-establishment of mechanical resilience in vivo, as required during keratin cytoskeleton remodeling in cell division and differentiation, which may lead to epithelial fragility in the gut. Simple epithelial keratins may thus be considered as candidates for genes contributing to a risk of inflammatory bowel disease.

Actin Cytoskeleton↗
PubMed2004

Abducens length and vulnerability?

BACKGROUND: Several sources have attributed the vulnerability of the abducens nerve to its long intracranial course. However, other anatomic factors likely contribute to the apparent vulnerability of the abducens nerve to mass lesions and trauma. METHODS: The authors performed a two-part anatomic study of the abducens nerve. In the first part of the study, they compared the length of the abducens with another cranial nerve, the trochlear, at the autopsy of 26 pediatric patients. In the second part of the study, the authors used an endoscopic exposure of these two cranial nerves in a preserved human cadaver head. RESULTS: The abducens nerve was consistently approximately one-third the length of the trochlear nerve at all ages that they studied. The endoscopic views revealed the structural and vascular relationships of the abducens nerve in situ. CONCLUSIONS: The authors conclude from these findings and the literature that abducens nerve vulnerability results from factors other than its intracranial length.

Abducens Nerve↗
PubMed2004

Anti-TNF therapy in Crohn's disease.

Anti-tumour necrosis factor (TNF) strategies, the most studied of biological therapies, include chimeric monoclonal (infliximab), humanized monoclonal (CDP571 and the PEGylated CDP870) and fully human monoclonal (adalimumab) antibodies, p75 fusion protein (etanercept), p55 soluble receptor (onercept) and small molecules such as MAPkinase inhibitors. The principal use of infliximab is in treating active Crohn's disease patients not responding to or intolerant of conventional therapies. Infliximab is steroid sparing. The development of antibodies against infliximab is associated with an increased risk of infusion reactions, and a reduced duration of response to treatment, and concomitant immunosuppressive therapy reduces the immunogenic response. The demonstration of the efficacy of maintenance therapy every 8 weeks with infliximab in the randomised, controlled, ACCENT I trial opened up the strategy for regular maintenance. In patients who have failed therapy with cortocosteroids and immunosuppressive therapy and are poor surgical candidates, and patients with fistulizing disease, where infliximab therapy is chosen, regular maintenance therapy with infliximab is likely to be required. On the other hand, patients with severely active, steroid-refractory disease in whom immunosuppressive therapy and infliximab are initiated together, may respond adequately and be continued on long-term immunosuppressive therapy alone. In ulcerative colitis the role of infliximab remains uncertain.

Antibodies, Monoclonal↗
PubMed2004

Synergistic effects of systemic trefoil factor family 1 (TFF1) peptide and epidermal growth factor in a rat model of colitis.

Novel therapies for the treatment of colitis are required. We therefore examined the potential value of the trefoil factor family 1 (TFF1) peptide and epidermal growth factor (EGF) alone and in combination. Effects of TFF1- Cys58 +/- EGF on an in vitro HT29 cell wounding model of restitution showed synergistic activity when used in combination. In addition, animals had colitis induced by adding 4% dextran sulphate sodium (DSS) to the drinking water for 7 days and they also received twice daily subcutaneous injections of test peptides. Treatment with TFF1-Cys58 alone (100 microg/kg) reduced histological colitis score by 22%, but the TFF1-Ser58 variant was ineffective. In a second study, TFF1-Cys58 reduced histological colitis score by 15%, EGF (600 microg/kg) by 26%, and an additive response (42% reduction) was demonstrated when used together (P < 0.01 versus either peptide given alone). Similar results were found using tissue myeloperoxidase (MPO) activity as a marker of inflammation. Where clinical risk/benefit seems justified, these initial studies suggest that combination therapy of systemic EGF and TFF peptides may prove useful for treatment of colitis in patients with disease extending beyond the reach of topical (enema) therapy.

Animals↗
PubMed2004

Novel mode of resistance to Fusarium infection by a mild dose pre-exposure of cadmium in wheat.

Exposure of healthy wheat seeds (Triticum aestivum var Sonalika) to mild dose of cadmium (Cd(2+)) given as 50 microM CdCl(2) for 48 h and then washed off Cd(2+) offered resistance to the subsequent infection by Fusarium oxysporum inoculum. Seven days old seedlings having two primary leaves were aseptically inoculated with fungus, F. oxysporum (1 x 10(6)) spores. The seedlings pre-exposed to low level of Cd(2+) survived the Fusarium infection, while plantlets without Cd(2+) stress wilted and then perished due to Fusarium infection. The stress associated proteins induced by Cd(2+) (50 microM), F. oxysporum and by the co-stress (50 microM Cd(2+) and then with F. oxysporum) treatments were observed to be of same molecular weight (51 kDa). Antibody was raised against the purified Cd(2+)-stress associated protein (CSAP). Immuno-gold labeling of wheat seedling root tissue showed the presence of this CSAP in Cd(2+) pre-exposed and in co-stressed tissues and to be located predominantly on the inner linings of the cell membranes. We also observed that the anti-CSAP-antibody also labeled the root tissue of only Fusarium inoculated seedlings and the gold labeling was intensely located on the membrane. This cross-reaction of anti-CSAP suggests that Fusarium-induced stress protein (FISP) possibly has close homology to CSAP. We thus show for the first time the over expression of a high molecular mass protein by mild dose of Cd(2+) pre-exposure to wheat seeds which subsequently provided protection against Fusarium infection. This mode of resistance developed by an abiotic stress-causing agent against pathogen infection is novel.

Blotting, Western↗