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Biomedical subjects

S Basu

Publications and source records attributed to S Basu.

At least 541 records · Page 30Linked to original sources
PubMed1966

Interaction of Vibrio cholerae and Vibrio El Tor.

Soon after its entry into the Indo-Pakistan subcontinent in 1964, cholera El Tor progressively replaced classical cholera. One of the probable reasons for this was found from laboratory studies of the interaction of the two choleragenic vibrios, V. cholerae and V. El Tor. It was observed, in both in vitro and in vivo experiments, that in mixed culture El Tor vibrios from cholera cases are capable of outgrowing and rapidly eliminating V. cholerae. The apathogenic El Tor strains from the Middle East countries differed significantly from the pathogenic type of El Tor strains isolated from cholera cases in that the former did not inhibit the growth of V. cholerae strains. The possible mechanism of interaction of the pathogenic El Tor vibrios and V. cholerae was studied in detail. Various possibilities, including higher rates of multiplication of El Tor vibrios, competition for nutrients, secretion of inhibitory substances and liberation of lethal bacteriophage or vibriocins by El Tor vibrios, were examined. Although it was not possible to establish the actual mechanism of this interaction, the possible biological effect on the epidemiology of cholera was evident.

Animals↗
PubMedDate not supplied

Implementation of a successful outpatient laparoscopic sterilization program in Calcutta.

This study presents data on 109 women undergoing laparoscopic sterilization by tubal rings at the Calcutta Medical Research Institute and Hospital. The average operating time was 15 minutes and the average stay in the recovery room was 4 hours. The overall complication rate was 18%, including surgical and early postoperative complications. All patients returned for follow-up. Long-term follow-up will be required to determine the rates of delayed complications and the efficacy of the procedure.

Adult↗
PubMedDate not supplied

Fanconi anemia.

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Child↗
PubMedDate not supplied

High-resolution ultrasound in the evaluation of the nonacute testis.

Ultrasound is the initial imaging modality used in the evaluation of the symptomatic testis. Ultrasound is painless and quick and supplements clinical examination of the testis. In this review, a range of testicular pathologies are discussed and sonographic examples illustrated. Particular attention is drawn to testicular microlithiasis and its relation to germ cell neoplasia and also to the sonographic features of epidermoid cysts that may allow testis-sparing surgery.

Humans↗
PubMedDate not supplied

Spontaneously active cells induce state transitions in a model of olfactory cortex.

The existence of neurons with intrinsic oscillations does not in itself explain the synchronization of local populations of neurons, but it is likely to pace population rhythms when the neurons are suitably coupled by chemical and/or electrical synapses. In the present study, we have investigated the role of spontaneously active cells as noisy or pacemaker units in setting global oscillations in a three-layered cortical model. The presence of a small number of noisy (spontaneously active) units induce oscillations at the network level in the range of the gamma rhythm. The number of noisy units in the network and their type (excitatory or inhibitory or excitatory and inhibitory together) determines the emergence of regular oscillations or aperiodic (chaotic) behaviour. It also determines the onset of the global behaviour. On replacing a noisy unit by a pacemaker unit, similar gamma oscillations were generated. With both noisy and pacemaker units, we found that certain characteristics of the spontaneous activity determine the delay period for the onset of global activity. Preliminary studies have been carried out with spontaneously active units having a chaotic dynamics but the results are much similar to that with a noisy burst. Different functional roles have been suggested for cortical oscillations, such as determining global functional states and specifying connectivity during development. Oscillations at different frequency bands, in particular in the gamma band (around 40 Hz), have also been associated with memory and attention. The presence of spontaneously active neurons, either with noisy or oscillatory activity, could be responsible for global oscillations in the absence of external stimuli in certain cortical areas in the mature brain.

Models, Neurological↗
PubMedDate not supplied

Application of tracer packet technique for multielemental uptake studies on the inorganic ion exchanger zirconium vanadate.

The conception of tracer packet was first started with the irradiation of a thick cobalt target with 16O, 7Li and 12C beams, consecutively. This produced carrier-free radiotracers of Mn, Cu, Zn, Ga, Ge, As and Se. These elements are adjacent members in the periodic table and are of nutritional importance. Another 'tracer packet', which was subsequently designed, was of heavy and toxic metals. A gold target irradiated with medium energy 7Li and 12C produced 197Hg, 200Tl, 200Pb, 204Bi, 204Po. The uptake of these elements has been studied using two different ion exchangers, one of inorganic origin and the other of chelating type.

Hydrogen-Ion Concentration↗
PubMedDate not supplied

Synthesis and characterization of a peptide nucleic acid conjugated to a D-peptide analog of insulin-like growth factor 1 for increased cellular uptake.

DNA therapeutics show great potential for gene-specific, nontoxic therapy of a wide variety of diseases. The deoxyribose phosphate backbone of DNA has been modified in a number of ways to improve nuclease stability and cell membrane permeability. Recently, a new DNA derivative with an amide backbone instead of a deoxyribose phosphate backbone, peptide nucleic acid (PNA), has shown tremendous potential as an antisense agent. Although PNAs hybridize very strongly and specifically to RNA and DNA, they are taken up by cells very poorly, limiting their potential as nucleic acid binding agents. To improve cellular uptake of a PNA sequence, it was conjugated to a D-amino acid analog of insulin-like growth factor 1 (IGF1), which binds selectively to the cell surface receptor for insulin-like growth factor 1 (IGF1R). The IGF1 D-peptide analog was assembled on (4-methylbenzhydryl)amine resin, and then the PNA was extended as a continuation of the peptide. The conjugate and control sequences were radiolabeled with 14C or fluorescently labeled with fluorescein isothiocyanate. Cellular uptake of the PNA-peptide conjugate, a control with two alanines in the peptide, and a control PNA without the peptide segment were studied in murine BALB/c 3T3 cells, which express low levels of murine IGF1R, in p6 cells, which are BALB/c 3T3 cells which overexpress a transfected human IGF1R gene, and in human Jurkat cells, which do not express IGF1R, as a negative control. The specific PNA-peptide conjugate displayed much higher uptake than the control PNA, but only in cells expressing IGF1R. This approach may allow cell-specific and tissue-specific application of PNAs as gene-regulating agents in vivo.

3T3 Cells↗
PubMedDate not supplied

Feasibility studies for a photosynthetic artificial lung. Optimization of parameters affecting photosynthesis.

As an alternative to conventional extracorporeal membrane oxygenation (ECMO) hardware, preliminary studies were conducted toward the development of a life support system based on biologic processes for the direct generation of O2 and removal of CO2 by the action of a photosynthetic organism. A high temperature strain of Chlorella pyrenoidosa, which functions optimally at 37 degrees C and pH 7.4, was cultured in a 3 I fermenter with artificial lighting provided with Hg-metal halide lights. The pH, total CO2 and partial pressure of oxygen (PO2) of the system were monitored at regular intervals using flow-through microelectrodes. The degree of importance of light intensity, substrate concentration, and cell density in the photosynthetic ability of Chlorella in batch culture were assessed over a 2 hour period. At high light intensities, the O2 production, CO2 removal, and pH changes were significantly greater than those at low irradiance levels. Over the range of HCO3- concentrations used in these experiments, the initial HCO3- levels did not appear to have a significant effect on the rates of O2 production/CO2 removal. The total amount of O2 produced/CO2 removed and pH changes were found to be greater with higher cell densities. Under more optimal culture conditions, it may be feasible to eventually interface this photobioreactor with blood across a semipermeable membrane and catalytically convert blood CO2 to O2 directly, needing only an adequate light source.

Artificial Organs↗
PubMedDate not supplied

Splenic metastases from cervical carcinoma: a case report.

Splenic metastasis from squamous cell carcinoma of the uterine cervix is an unusual event in the natural history of the disease. The authors report one such uncommon occurrence in a 41-year-old female who presented initially with cervical carcinoma (stage IIB) and was treated with radical radiotherapy with concurrent weekly chemotherapy. Following a disease-free interval of less than a year, she developed hepatosplenic metastases despite being locally controlled. The literature relevant to the report is also discussed. This report reaffirms the notion that splenic metastases from cervical carcinoma are rare events but can occur as part of widespread dissemination.

Adult↗
PubMedDate not supplied

Relationships between endothelium-dependent vasodilation, serum vitamin E and plasma isoprostane 8-iso-PGF(2alpha) levels in healthy subjects.

Due to the reported associations between a low intake of vitamin E and atherosclerosis on one hand, and between endothelial dysfunction and atherosclerosis on the other hand, we investigated the relationship between endothelium-dependent vasodilation and serum levels of vitamin E (alpha- and gamma-tocopherol) as well as the lipid peroxidation markers malondialdehyde and 8-iso-PGF(2alpha) in a healthy population. Healthy subjects (31 men and 25 women), aged between 20 and 69 years, underwent measurements of forearm blood flow (FBF) at rest and during local infusion of 2 and 4 microg/min of methacholine (Mch, to evaluate endothelium-dependent vasodilation) and 5 and 10 microg/min of sodium nitroprusside (SNP, to evaluate endothelium-independent vasodilation, and during reactive hyperemia using venous occlusion plethysmography. Serum alpha-tocopherol concentration was significantly related to the index of endothelial function (r = 0.46, p < 0.01), defined as the ratio between the maximal dilatations during Mch and SNP infusions. Serum gamma-tocopherol levels were positively related to the maximal FBF during reactive hyperemia (r = 0.54, p < 0.01) in women only. Furthermore, in women only, plasma 8-iso-PGF(2alpha) levels were inversely related to the relative increases in FBF during both Mch and SNP infusions (r = -0.58 and r = -0.59, p < 0.01 for both). The results show a relationship between the levels of alpha-tocopherol and endothelial vasodilatory function, suggesting a beneficial role for this potent lipid-soluble antioxidant also in a population sample of apparently healthy subjects. Furthermore, in women, the accumulation of lipid peroxidation products such as 8-iso-PGF(2alpha) seems to be associated with an impaired vasodilation in general.

Adult↗
PubMedDate not supplied

Modulation of Bcl-2 family proteins in primary endothelial cells during apoptosis.

We studied the expression of Bcl-2 family proteins during cytokine- and verotoxin (VT)-induced apoptosis in primary human umbilical vein endothelial cells (HUVECs). Our experiments demonstrated that high initial expression of Bcl-2 protein was significantly downregulated in HUVECs treated with IFN-gamma whereas TNF-alpha gave a less pronounced decrease in Bcl-2 level. Treatment with the combination of cytokines was more efficient in downregulating Bcl-2 protein. HUVECs pretreated with cytokines and incubated with VT gave a further significant decrease in Bcl-2 level. Simultaneous measurement of Bcl-xl level did not reveal any significant changes. Bax protein was upregulated in HUVECs stimulated with TNF-alpha alone or in combination with IFN-gamma. However, addition of VT did not give any further increase in Bax level suggesting that Bax upregulation is more important for cytokine- rather than VT-mediated apoptosis. Total endothelial cell growth factor deprivation gave a significant increase in apoptosis accompanied by a decrease of Bcl-2 in apoptotic cells while Bcl-xl and Bax levels were unaffected. Our data indicate that anti-apoptotic protein Bcl-2 and pro-apoptotic protein Bax are reciprocally regulated during apoptosis, whilst Bcl-xl is essentially unaffected. This implies that Bcl-2/Bax ratio rather than Bcl-xl controls apoptosis in primary endothelial cells.

Apoptosis↗
PubMedDate not supplied

Fine needle aspiration of angiomatoid malignant fibrous histiocytoma. A case report.

BACKGROUND: During recent years, reliable cytodiagnostic criteria have been proposed for a number of soft tissue lesions, both benign and malignant. However, cytomorphologic descriptions of angiomatoid malignant fibrous histiocytoma (AMFH) are lacking. We report the cytomorphologic features of this uncommon lesion. CASE: A 10-year-old female presented with a swelling in the thigh that, on fine needle aspiration (FNA), was reported as a soft tissue tumor (vasoformative) of intermediate malignancy. Subsequent excision with histopathologic examination confirmed the diagnosis. CONCLUSION: The differential diagnosis of AMFH based on FNA findings can be difficult and should be made in conjunction with clinical findings.

Biopsy, Needle↗
PubMedDate not supplied

Molecular arrangement of DNA in nucleohistone.

Several optical and hydrodynamic properties of purified nucleohistone have indicated that the secondary structure of DNA in nucleohistone is slightly different both from the structures of native and denatured DNA in solution. It has been suggested that while histones stabilize the overall DNA-structure they incorporate into the latter some denaturation defects. Rotational diffusion studies of acridine-orange complexes of whole and dehistonized nucleohistones have indicated that nucleohistone should contain a single continuous DNA molecule. The contour length of the DNA molecule would be about 2 to 3 times the end-to-end distance of nucleohistone. Polarized fluorescence microscopy and linear dichroism studies of whole nucleohistone have given an average estimate (about 30% of the total CNA) of oriented DNA in nucleohistone. The degree and the direction of maximum polarization of fluorescence from the dye complexes of whole and partial (i.e. partially dissociated) nucleohistones have been studied. From these studies, it is proposed that no single supercoiled arrangement of the DNA in nucleohistone is tenable. The combined results of all these studies suggest that the basic nucleohistone molecule contains coiled and extended DNA regions. The proportion of the lengths of the DNA constrained in the coiled and the extended regions is about 7:3. Only two probable models or classes have this quantitative feature of the DNA-arrangement and have been discussed.

DNA↗
PubMedDate not supplied

Cancer services.

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Hematology↗