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Biomedical subjects

A Ghosh

Publications and source records attributed to A Ghosh.

At least 37 records · Page 2Linked to original sources
PubMed2005

Radioactivity studies along fracture zones in areas around Galudih, East Singhbhum, Jharkhand, India.

The application of radon to delineate geological processes like faulting and deformation, groundwater flow and contamination have assumed considerable significance over the last decade due to low-level detection capabilities and long-distance time migration. Suitable modeling procedures have helped in quantification of radon emanation and migration along active and passive faults. In the present study, we have attempted to correlate the radionuclide content and the extent of fracturing. For this purpose, quartzites occurring around Galudih, Jharkhand State, India, have been investigated. The study includes fracture density measurements at selected outcrops and joint analyses to evaluate the relationship between radionuclides and mesoscopic fractures. Moreover, microstructural studies have also been performed to decipher any existing relationship between radionuclides and microscale deformation mechanisms. It has been found that the microstructural phenomena are more important than mesoscopic scale processes and the former controls the concentration of radionuclides in rocks.

Journal Article↗
PubMed2005

Complete substitution of cyclophosphamide by fludarabine and ATG in a busulfan-based preparative regimen for children and adolescents with beta-thalassemia.

Children and adolescents with homozygous beta-thalassemia can be cured by transplantation of normal stem cells after eradication of the thalassemic hematopoietic system. In an attempt to achieve durable engraftment and to minimize regimen-related toxicity (RRT), we have initiated a fludarabine-based pilot protocol not containing cyclophosphamide. Between 1999 and 2004, five children with beta-thalassemia major were enrolled. Median age at transplantation was 11.5 years (range 4-14 years). Three patients received conditioning with fludarabine (30 mg/m2/day x 6), oral busulfan (3.5 mg/kg/day x 4), and ATG rabbit Fresenius (10 mg/kg/day x 4). Two children received intravenous busulfan instead of oral busulfan at a dose of 2 x 1.4 mg/kg/day x 4 days. All children were transplanted with a fresh bone marrow graft from an HLA-identical sibling. Mean cell doses given were 3.7 x 10(8) nucleated cells/kg BW (range 2.4-6.2 x 10(8)/kg). Overall, 5/5 patients achieved donor engraftment and are alive and well. No GVHD exceeding grade I was observed, and 2/5 children maintained donor chimerism at 100%. One patient maintains mixed hematopoietic donor chimerism being between 94 and 97% nearly 5 years after transplant.

Adolescent↗
PubMed2005

Driving midgut-specific expression and secretion of a foreign protein in transgenic mosquitoes with AgAper1 regulatory elements.

The Anopheles gambiae adult peritrophic matrix protein 1 (AgAper1) regulatory elements were used to drive the expression of phospholipase A2 (PLA2), a protein known to disrupt malaria parasite development in mosquitoes. These AgAper1 regulatory elements were sufficient to promote the accumulation of PLA2 in midgut epithelial cells before a blood meal and its release into the lumen upon blood ingestion. Plasmodium berghei oocyst formation was reduced by approximately 80% (74-91% range) in transgenic mosquitoes. Blood-seeking behaviour and survival of AgAper1-PLA2 transgenic mosquitoes were comparable to sibling wild-type mosquitoes, while fertility was substantially lower. Ultrastructural studies suggest that decreased fitness is a consequence of internal damage to midgut epithelial cells.

Animals↗
PubMed2005

A practical definition of conduction block in IvIg responsive multifocal motor neuropathy.

BACKGROUND: Multifocal motor neuropathy with conduction block (MMN) can be mistaken for motor neurone disease or other lower motor neurone syndromes, but is treatable with intravenous immunoglobulin (IvIg). Formal electrophysiological criteria for conduction block (CB) are so stringent that substantial numbers of patients may miss out on appropriate treatment. METHODS: Electrophysiological data were collected from 10 healthy volunteers and compared to data from 10 patients who satisfied the clinical criteria for MMN and who responded to IvIg. This produced a definition of CB in MMN patients which was compared with existing definitions to assess "miss rates". RESULTS: Mean values for compound muscle action potential area, amplitude, and duration were calculated in normal subjects. Results beyond 3 SD of their respective means were considered abnormal. Using these criteria, CB in the context of MMN was defined as a reduction in negative peak area >23% along a distal nerve segment or >29% across a proximal segment; or a reduction in amplitude >32% across a distal segment or >33% across a proximal segment. All IvIg responsive patients had at least one nerve segment showing such CB. Employing some criteria from the literature would have denied treatment to over 30% of responsive patients. CONCLUSION: In the clinical setting of suspected MMN, less stringent criteria for CB can improve the diagnosis of this treatable disorder. Exclusions on grounds of temporal dispersion may be over-restrictive. A little over one third of CBs occur proximally.

Action Potentials↗
PubMed2005

The effect of treatment upon temporal dispersion in IvIg responsive multifocal motor neuropathy.

BACKGROUND: Multifocal motor neuropathy with conduction block (MMN) is a treatable disorder that can be mistaken for other lower motor neurone syndromes. Existing electrophysiological diagnostic criteria for MMN are restrictive. In particular, many are cautious about diagnosing conduction block (CB) in the presence of abnormal temporal dispersion (TD). OBJECTIVE: To study the significance of TD in MMN, its relationship to CB in intravenous immunoglobulin (IvIg) responsive patients, and its utility in detecting a treatment response. METHODS: We compared pre- and post-treatment changes in CB and TD in nine patients who satisfied clinical and electrophysiological criteria for MMN and responded to IvIg. RESULTS: TD improved in one or more nerve segments in eight of nine patients tested. There was marked improvement in 65% of all nerve segments, and 60% of those segments with CB. By comparison, significant improvement in CB occurred in only 33% of segments. Of segments with significantly better CB after treatment, all but one showed similar improvements in TD. Such changes were not related to the degree of TD before treatment, being seen in segments with abnormal as well as normal TD. There was no correlation between improvements seen in TD and CB. CONCLUSION: We believe that TD should be considered an inherent feature of MMN. Improvement in TD is an independent marker of electrophysiological improvement in this disorder and is likely to be more useful than CB. When MMN is clinically suspected, the use of stringent criteria for CB in the presence of TD should be avoided.

Action Potentials↗
PubMed2005

Primary neurological manifestations of lung cancer--a retrospective analysis of 8 patients.

Neurological manifestations are reported in 5 to 10% of cases of lung cancer. We present a series of 216 consecutive patients of lung cancer of which 8 patients presented first with neurological manifestations without overt respiratory symptoms. The present study aimed to identify the number of patients of lung cancer presenting with primary neurological symptoms, the nature of the presentations, and the outcome of these patients among 216 patients who presented over a 2 year period in the Institute of Postgraduate Medical Education and Research, Kolkata. Out of 8 patients, 3 patients presented with seizures, 3 patients with hemiparesis and 2 patients with paraparesis. Thus, 3.7% (8/216) of patients in our series presented with a neurological manifestation. We concluded that primary neurological manifestations are rare in lung cancer. The lungs should be the first site of evaluation in a case of a cerebral metastasis with an unknown primary.

Adult↗
PubMed2005

Alteration of blood pressure among the donors in a blood donation camp.

Anxiety can alter the cardiovascular parameters. In the present study, among the normotensive donors, the effect of anxiety on alteration of blood pressure and heart rate was assessed. Blood pressure and pulse rate were recorded in the volunteers just before blood donation and the results were compared with the blood pressure and heart rate recorded previously (one week before the camp) in the same population. There was a rise of both systolic and diastolic blood pressure with a significant increase in pulse rate just before blood donation. As the donors had previous experience of blood donation; the mental stress just before blood donation can be regarded as known stress -- which caused increase in norepinephrine secretion leading to peripheral vasoconstrictions and rise in diastolic blood pressure. Anxiety through sympathetic stimulation increased the heart rate, cardiac output and systolic blood pressure.

Adolescent↗
PubMed2005

Heavy metals in water of the rivers Hooghly and Haldi at Haldia and their impact on fish.

The paper deals with the measurement of five heavy metals viz., Cd, Cu, Mn, Pb and Zn in water of the rivers Hooghly and Haldi at Haldia during June 1999 to October 2002. The industrial effluent out fall (OF) at Patikhali, Haldia was also taken as sampling site along with above out fall (AOF) and below out fall (BOF) sites. Most of the metals exhibited their least concentration at the sampling site above the Haldia industrial area of river Hooghly. The average concentrations of the studied metals were Cd 2-14, Cu 5-19, Mn 8-88, Pb 17-41 and Zn 22-37 microg l(-1). Comparison of the data with the Criterion Continuous Concentration (CCC) of USA revealed that Cd, Cu and Pb were the pollutants present at alarming level to disturb the aquatic life process in the zone. The effect was found to reflect on the tissue level aberrations in the residential fishes. The other two metals viz., Mn and Zn were probably less harmful to the aquatic ecosystem. In India, necessity is felt to develop the CCC values, which will be more appropriate for protection of aquatic environment than comparing with drinking water standards.

Animals↗
PubMed2004

Atmospheric imaging results from the Mars exploration rovers: Spirit and Opportunity.

A visible atmospheric optical depth of 0.9 was measured by the Spirit rover at Gusev crater and by the Opportunity rover at Meridiani Planum. Optical depth decreased by about 0.6 to 0.7% per sol through both 90-sol primary missions. The vertical distribution of atmospheric dust at Gusev crater was consistent with uniform mixing, with a measured scale height of 11.56 +/- 0.62 kilometers. The dust's cross section weighted mean radius was 1.47 +/- 0.21 micrometers (mm) at Gusev and 1.52 +/- 0.18 mm at Meridiani. Comparison of visible optical depths with 9-mm optical depths shows a visible-to-infrared optical depth ratio of 2.0 +/- 0.2 for comparison with previous monitoring of infrared optical depths.

Algorithms↗
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

Basaltic rocks analyzed by the Spirit Rover in Gusev Crater.

The Spirit landing site in Gusev Crater on Mars contains dark, fine-grained, vesicular rocks interpreted as lavas. Pancam and Mini-Thermal Emission Spectrometer (Mini-TES) spectra suggest that all of these rocks are similar but have variable coatings and dust mantles. Magnified images of brushed and abraded rock surfaces show alteration rinds and veins. Rock interiors contain </=25% megacrysts. Chemical analyses of rocks by the Alpha Particle X-ray Spectrometer are consistent with picritic basalts, containing normative olivine, pyroxenes, plagioclase, and accessory FeTi oxides. Mössbauer, Pancam, and Mini-TES spectra confirm the presence of olivine, magnetite, and probably pyroxene. These basalts extend the known range of rock compositions composing the martian crust.

Extraterrestrial Environment↗
PubMed2004

Possible evidence of a spontaneous spin polarization in mesoscopic two-dimensional electron systems.

We have experimentally studied the nonequilibrium transport in low-density clean two-dimensional (2D) electron systems at mesoscopic length scales. At zero magnetic field (B), a double-peak structure in the nonlinear conductance was observed close to the Fermi energy in the localized regime. From the behavior of these peaks at nonzero B, we could associate them with the opposite spin states of the system, indicating a spontaneous spin polarization at B=0. Detailed temperature and disorder dependence of the structure shows that such a splitting is a ground-state property of low-density 2D systems.

Journal Article↗
PubMed2004

Documentation of immune profile of microglia through cell surface marker study in glioma model primed by a novel cell surface glycopeptide T11TS/SLFA-3.

STATEMENT OF THE PROBLEM: The sheep erythrocyte membrane glycoprotein T11TS/SLFA-3 can form a ligand-receptor complex with CD2 present on immunocyte and exert stimuli for activation and proliferation. Regression of brain tumor with the application of T11TS indicates the probable role of microglia, the chief immunomodulatory cell within the brain compartment. In the present study microglial activation and immunophenotypic modulation were assessed in T11TS treated brain tumor-bearing animal models. Rat glioma models induced by chemical carcinogen ENU were treated with three consecutive doses of T11TS. Microglial cells from brain were isolated and assessed through E-rosette formation, SEM and FACS for CD2, MHC class II, CD25, and CD4. The preliminary indication of presence of CD2 on microglia through E-rosette formation was confirmed by SEM and FACS. MHC class II and CD2 single and double positive subpopulations exist, and their expression is also modulated in different doses of T11TS. A general trend of highest receptor saturation and microglial activation, measured through the activation marker CD25 and CD4 expression, was observed in 2nd dose of T11TS administration, which was then dampened via a complex immune feedback mechanism in the 3rd dose.

Alkylating Agents↗
PubMed2004

A comparative analysis of immunorestoration and recovery with conventional and immunotherapeutic protocols in canine generalized demodicosis: a newer insight of immunotherapeutic efficacy of T11TS.

Demodex canis is a natural inhabiting mite of canine skin. Immunological disorder or genetic disorder induces the Demodex population to proliferate vigorously resulting in generalized demodicosis with consequent chronic immunosuppression. Signs of generalized demodicosis include alopecia, crysting, erythema, secondary pyoderma etc. Amitraz, an acaricide, is used conventionally for the treatment of generalized demodicosis. In many instances, the disease relapses due to the residual immunosuppression. The need of an immunorestorative therapy has been urged in generalized demodicosis. Two immunorestorative drugs, namely, Immuplus, a herbal drug, and T11TS, a sheep erythrocyte surface glycoprotein, has been used in two separate groups of dogs having generalized demodicosis and receiving Amitraz treatment. It was observed that though Amitraz treated group responded to the therapy showing increased E-rosettes and nonspecific cytotoxic efficacy of T-lymphocytes and decrease in phagocytic potential of macrophages, the groups treated with the immunotherapeutics like Immuplus and T11TS, responded better. However, the group treated with T11TS showed best recovery. These results emphasize the need for an immunorestorative therapy in generalized demodicosis and provide data in favor of T11TS as a better immunomodulator in comparison to Immuplus.

Animals↗