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Biomedical subjects

S Ghose

Publications and source records attributed to S Ghose.

At least 37 records · Page 2Linked to original sources
PubMed1999

Mobilization of intracellular calcium stores participates in the rise of [Ca2+]i and the toxic actions of the HIV coat protein GP120.

The HIV envelope glycoprotein, GP120, increases intracellular Ca2+ concentration and induces degeneration of human and animal neurons in culture. Using patch-clamp recordings and Ca2+ imaging techniques, we have now examined the contribution of intracellular stores of calcium in the effects of GP120. We report that in rat hippocampal neuronal cultures, GP120 induces a dramatic and persistent increase in [Ca2+]i which is prevented by drugs that either deplete (caffeine, carbachol, thapsigargin) or block (dantrolene) Ca2+ release from intracellular stores. In contrast, N-methyl-d-aspartate (NMDA) receptors or voltage-dependent calcium channels do not participate in these effects, as: (i) the increase in [Ca2+]i was not affected by NMDA receptor antagonists or calcium channel blockers; and (ii) and GP120 did not generate any current in whole-cell recording. Dantrolene, a ryanodine stores inhibitor, also prevented neuronal death induced by GP120. Our results show that the GP120-induced rise in [Ca2+]i originates from intracellular calcium stores, and suggest that intracellular stores of calcium may play a determinant role in the pathological actions of GP120.

Animals↗
PubMed1999

Ocular extramedullary myeloid cell tumour in children: an Indian study.

Thirty-two children with extramedullary myeloid cell tumour (EMT) who constituted 41 per cent of children with acute myeloid leukaemia (AML) were studied to ascertain their laboratory characteristics and potential problems in diagnosis. The diagnosis, established by peripheral blood smear and/or bone marrow examination, was AML (n = 29) and refractory anaemia with excess blasts in transformation (RAEB-t; n = 3). The six referred patients in whom the diagnosis had been missed, and two cases wrongly reported as histiocytosis on aspiration cytology, were those in whom a peripheral blood smear had not been examined. It is concluded that diagnostic work-up of proptosis must include a full haemogram, meticulous peripheral blood smear examination, repeated if necessary, and bone marrow examination where relevant. RAEB-t cases with extramedullary myeloid cell tumour should be classified as acute myeloid leukaemia.

Acute Disease↗
PubMed1999

The effect of column verticality on separation efficiency in expanded bed adsorption.

The effect of column verticality on liquid dispersion and separation efficiency in expanded bed adsorption columns was investigated using 1 and 5 cm diameter columns. Column misalignment of only 0.15 degree resulted in the reduction of the Bodenstein number from 140 to 50 for the 1 cm dia. column and from 75 to 45 for the 5 cm dia. column. This degree of misalignment was not detectable by visual assessment of adsorbent particle movement within the column. Depending on the relative importance of transport limitations, kinetic limitations and dispersion to any specific separation, this increase in dispersion with column alignment can significantly affect separation efficiency. Pure protein breakthrough profiles resulting from the application of bovine serum albumin onto STREAMLINE Q XL demonstrated that, at 10% breakthrough, 7.8% more protein could be applied to a vertical 1 cm dia. column compared to the same column misaligned by 0.15 degree. When an unclarified yeast homogenate was applied to a 1 cm dia. vertical column packed with STREAMLINE DEAE, 10% breakthrough of glucose-6-phosphate dehydrogenase (G6PDH) corresponded to a load 55% greater compared to the same column aligned 0.185 degree off-vertical. The G6PDH breakthrough curves for vertical and 0.15 degree off-vertical runs performed using a 5 cm column were essentially indistinguishable.

Adsorption↗
PubMed1999

Nongonadal neoplasia in patients with Turner syndrome.

In a prospective study of 50 patients with retinoblastoma, a 10-year-old girl with unilateral (right eye) retinoblastoma was found to have 45,X karyotype. Because there is increasing evidence of nongonadal neoplasia occurring in patients with Turner syndrome in addition to the gonadal tumor from dysgenetic gonads, we reviewed the occurrence of nongonadal neoplasia in Turner syndrome cases. Of all the nongonadal neoplasia, neurogenic tumors show a preponderence among children and young adults with Turner syndrome. To the best of our knowledge, this is the first reported case of Turner syndrome with retinoblastoma. The available literature strongly suggests that patients with Turner syndrome may be at risk of developing neurogenic tumors. Further studies are necessary to identify the role of some X-linked genes that escape X-inactivation in tumorigenesis in patients with Turner syndrome.

Child↗
PubMed1997

Absence of pericentromeric heterochromatin (9qh-) in a patient with bilateral retinoblastoma.

The polymorphisms of constitutive heterochromatin regions, present on chromosomes 1, 9, 16 and Y, are inherited in a Mendelian fashion. The C-band heteromorphism has been reported to be associated with various types of cancer. Heterochromatin is considered to play a role in protecting genome against the mutagens. Changes in the quantity and proportion of the different types of satellite DNA might increase the genetic susceptibility in people with heterochromatic variations, which in turn cause chromosome instability and predispose the individual to cancer. We report a case of bilateral retinoblastoma with complete absence of pericentromeric heterochromatin on one of the chromosomes number 9. A similar deficiency of pericentromeric heterochromatin on chromosome number 9 and 16 has been reported in a phenotypically normal individual and a Down syndrome case, respectively. This deficiency was found to be inherited from the father in all the three cases. Complete absence of pericentromeric heterochromatin of chromosome 9 is not being reported in association with cancer syndromes. Further studies are necessary to understand the role of this factor in normals and in those with cancer susceptibility, specially with retinoblastoma and the paternal origin of this deficiency.

Chromosome Deletion↗
PubMed1997

N-acetylaspartylglutamate stimulates metabotropic glutamate receptor 3 to regulate expression of the GABA(A) alpha6 subunit in cerebellar granule cells.

We have shown that the vertebrate neuropeptide N-acetylaspartylglutamate (NAAG) meets the criteria for a neurotransmitter, including function as a selective metabotropic glutamate receptor (mGluR) 3 agonist. Short-term treatment of cerebellar granule cells with NAAG (30 microM) results in the transient increase in content of GABA(A) alpha6 subunit mRNA. Using quantitative PCR, this increase was determined to be up to 170% of control values. Similar effects are seen following treatment with trans-1-aminocyclopentane-1,3-dicarboxylate and glutamate and are blocked by the mGluR antagonists (2S,3S,4S)-2-methyl-2-(carboxycyclopropyl) glycine and (2S)-alpha-ethylglutamic acid. The effect is pertussis toxin-sensitive. The increase in alpha6 subunit mRNA level can be simulated by activation of other receptors negatively linked to adenylate cyclase activity, such as adenosine A1, alpha2-adrenergic, muscarinic, and GABA(B) receptors. Forskolin stimulation of cyclic AMP (cAMP) levels abolished the effect of NAAG. The change in alpha6 levels induced by 30 microM NAAG can be inhibited in a dose-dependent manner by simultaneous application of increasing doses of the beta-adrenergic receptor agonist isoproterenol. The increase in alpha6 mRNA content is followed by a fourfold increase in alpha6 protein level 6 h posttreatment. Under voltage-clamped conditions, NAAG-treated granule cells demonstrate an increase in the furosemide-induced inhibition of GABA-gated currents in a concentration-dependent manner, indicating an increase in functional alpha6-containing GABA(A) receptors. These data support the hypothesis that NAAG, acting through mGluR3, regulates expression of the GABA(A) alpha6 subunit via a cAMP-mediated pathway and that cAMP-coupled receptors for other neurotransmitters may similarly influence GABA(A) receptor subunit composition.

Animals↗
PubMed1997

Radioactivity in sediments of the Karnaphuli river estuary and the Bay of Bengal.

Sediment samples from the Karnaphuli river estuary, nearshore, and off-shore regions off the coast of Chittagong in the Bay of Bengal were analyzed for the natural radioactivity contents of 232Th, 238U and 40K and anthropogenic radioactivity contents of 137Cs and 134Cs using HPGe gamma spectrometry, together with the measurement of sediment pH and grain size analyses of the collected samples. The activity of 232Th found in sediment ranged from 10.44 +/- 2.31 to 64.02 +/- 8.13 Bq kg(-1), 238U activity ranged from 5.87 +/- 1.21 to 27.85 +/- 1.71 Bq kg(-1), 40K activity from 118.28 +/- 19.70 to 608.21 +/- 75.70 Bq kg(-1), and the activity 137Cs ranged from 0.09 +/- 0.06 to 4.64 +/- 0.19 Bq kg(-1), no 134Cs radioactivity was detected at any of the sampling stations.

Geologic Sediments↗
PubMed1995

Frog prohormone convertase PC2 mRNA has a mammalian-like expression pattern in the central nervous system and is colocalized with a subset of thyrotropin-releasing hormone-expressing neurons.

The prohormone convertase (PC2) is expressed in the mammalian central nervous system (CNS) and has been shown to play an important role in the processing of certain neuropeptide precursors and prohormones at paired basic residues. Amphibian PC2 cDNA was recently cloned for the frog Xenopus laevis, and both its sequence and its pituitary expression pattern were shown to be very similar to those of mammalian PC2. To investigate further the function of PC2 in the vertebrate CNS, we used in situ hybridization histochemistry to localize the distribution of cells expressing PC2 mRNA in the frog brain and the spinal cord. The distribution of PC2-expressing cells was also compared with that of cells expressing thyrotropin-releasing hormone (TRH) mRNA or peptide. PC2-expressing cells were detected in specific nuclei that were widely distributed in the frog CNS. In forebrain, telencephalic PC2 mRNA was found in the olfactory bulb, pallium, striatum, amygdala, and septum, and diencephalic PC2 mRNA was seen in the preoptic area, thalamus, and hypothalamus. More posteriorly, PC2 cells were localized to midbrain tegmentum, the torus semicircularis, and the optic tectum, as well as the cerebellum, brainstem, and spinal cord. Despite this wide distribution steady-state levels of PC2 mRNA were clearly different in various brain nuclei. Regions with higher levels showed good correspondence to areas shown by others in frog to contain large numbers of neuropeptide-expressing cells, including TRH cells. On the other hand, not all brain areas with high levels of TRH mRNA had high levels of PC2 mRNA. Localization studies combining in situ hybridization and immunocytochemistry showed that, at least in optic tectum and brainstem, PC2 mRNA and pro-TRH peptide coexist. These findings suggest that pro-TRH is processed by PC2 in some, but possibly not all, brain regions. Thus, different converting enzymes may be involved in pro-TRH processing in different brain regions.

Animals↗
PubMed1995

Radioactivity in marine fish of the Bay of Bengal.

The concentrations of natural radionuclides of 40K, 232Th and 238U and artificial radionuclides of 137Cs and 134Cs in different marine fish samples from the Bay of Bengal were determined. In some of the fish samples contamination of the 137Cs radionuclide was observed, but 134Cs was below detection level.

Animals↗
PubMed1994

Price: a market signal of quality in health care insurance policies?

Choosing a good quality health insurance policy is important for most individuals in this country. The choice task is however, made quite complicated by the existence of many alternative policies which are each characterized by multiple attributes. This paper examines whether the price (i.e., premium) of a health insurance plan can give a reliable signal about the objective quality level of the plan. Empirical analysis of real-world data shows that overall, price is positively correlated with such quality. Statistical significance tests are conducted to separately evaluate such correlations for different categories of health insurances. Finally, the empirical results are used to indicate implications for consumer decision making.

Community Participation↗
PubMed1993

The optic nerve in children with craniosynostosis. A pre and post surgical evaluation.

Optic nerve (ON) damage especially from papilloedema can be prevented with timely detection. The detailed ocular and radiographic status of 33 unoperated craniosynostosis (CS) was documented prospectively; the ON was also assessed by flash VER and A-scan echography for ON thickness. Fluorescein angiography (FA) was done for all suspected and early papilloedemas. ON involvement diagnosed in 10/33 showed highly significant correlations with multiple suture synostoses (p = 0.004) and exorbitism (p < 0.001). VER latency was increased in all 5 ON atrophies; and also in 1/5 papilloedemas without atrophic changes, urgent surgery in which reversed VER changes, and vision later improved from 6/60 to 6/9. FA was valuable for confirming the clinical diagnosis of the earliest papilloedemas; the FA also returned to normal with immediate therapy along with reversal of the clinical picture. ON echography especially helped in monitoring regression of disc oedema. Ours seems the first report especially in CS where a critical follow-up of all above parameters in 21 operated/33 could objectively establish the role of each investigation in conjunction with careful clinical monitoring especially of the ON head. Such comprehensive evaluation should help reduce the blindness often seen in such children.

Adolescent↗
PubMed1993

Positioning health services: a mapping approach.

The proliferation of different kinds of health services has created a "clutter" in the industry making it difficult to distinguish between different product/service offerings. This often leads to fuzzy positioning in the market which helps neither the firm providing a health service nor the potential consumers. In this paper we propose the use of map representations to provide health care managers with diagnostic information about the market and to assist them in their service design and positioning tasks. Empirical analysis of a real-life objective data set is employed to illustrate the appropriateness of the proposed mapping approach for the health insurance industry. The paper also emphasizes the difference in the characteristics and implications of non-price scaled vs. price scaled maps in the context of health care marketing.

Computer Simulation↗
PubMed1993

Protein adsorption to hydrophobic Zeolite Y: salt effects and application to protein fractionation.

The binding equilibria of proteins with a hydrophobic variety of crystalline Zeolite Y is affected by salt and is a function of the type of salt and its concentration. The behaviour does not always follow the conventional pattern of increased binding at high salt concentrations and varies also for the different proteins involved. The overall process may be looked upon as a salting-in/salting-out mechanism. This material can be used as a surface for the selective adsorption of proteins and has been applied for the fractionation of ox heart homogenate in multi-stage operations. The presence of NaCl influences the protein binding, and this can be seen by monitoring the activity profile of lactate dehydrogenase. The bound protein can be reversed by treating the equilibrium mixture with low-molecular-mass poly(ethylene glycol)s.

Adsorption↗
PubMed1993

Spontaneous hyphema in an infant with Christmas disease.

A 4-month-old boy presented with an apparently spontaneous uniocular hyphema as the initial manifestation of Christmas disease (hemophilia B). Although it is uncommon for patients with hemophilia to experience major bleeds in infancy, and the ocular involvement is usually limited to periocular hemorrhages, we recommend that a coagulation profile be obtained in all patients with intraocular hemorrhage to rule out this disease.

Blood Coagulation Tests↗
PubMed1991

Evaluation of displacement chromatography for the recovery of lactate dehydrogenase from beef heart under scale-up conditions.

A complex mixture of proteins was subjected to displacement development from a Tris Acryl DEAE anion-exchange column. Lactate dehydrogenase was used as the target protein in the evaluation of the resolution and separation under scale-up conditions. The conditions of operation were scaled up in terms of column size and protein load. Column length was found to play an important role in resolving the mixture. The performance of the displacement mode run was compared with a conventional ion-exchange elution run in terms of fraction purity and specific activities. In general, displacement chromatography of the complex mixture yielded better results.

Animals↗