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Biomedical subjects

N Jain

Publications and source records attributed to N Jain.

At least 73 records · Page 4Linked to original sources
PubMed1999

UPPER III: unified physical property estimation relationships. Application to non-hydrogen bonding aromatic compounds.

The UPPER scheme uses four additive and two nonadditive parameters and several well-known equations to calculate 21 physical properties of organic compounds strictly from molecular structure. The scheme allows reasonable estimations of melting and boiling points, aqueous and octanol solubilities, air-octanol, air-water, and octanol-water partition coefficients, vapor pressure, and other properties. In this report non-hydrogen bonding aromatic compounds are used to evaluate a portion of the UPPER scheme.

Algorithms↗
PubMed1999

Inverted pyramidal neurons in chimpanzee sensorimotor cortex are revealed by immunostaining with monoclonal antibody SMI-32.

We used the monoclonal antibody SMI-32 to label pyramidal cells of sensorimotor cortex in two chimpanzees. The majority of the pyramidal cells had typical vertically oriented apical dendrites that extended towards the pial surface. A small population of pyramidal cells varied from this orientation, so that the apical dendrites were 20 degrees or more from radial, and were often inverted, extending away from the pial surface. When numbers of non-inverted and inverted pyramidal cells were compared, less than 1% were found to be inverted.

Animals↗
PubMed1999

Mortality trends in falciparum malaria--effect of gender difference and pregnancy.

Falciparum malaria in pregnancy is a significant health problem in India. Pregnant women constitute an important high risk group for malaria infection which may cause abortions, stillbirths, intra-uterine growth retardation (IUGR) and premature labour. In this hospital based study on 602 admitted patients of falciparum malaria which included 314 males, 243 non-pregnant females and 45 pregnant females, there was significantly increased mortality rate in females (18.4%) in comparison to males (7.64%, p < 0.001). The mortality rate was highly significant in pregnant females (37.77%) in comparison to non-pregnant females (14.81%) and males (7.64%; p < 0.001). Severe anaemia with Hb < 5 gm% was observed more commonly in pregnant patients (20.0%) in comparison to non-pregnant patients (4.11%). Incidence of malaria infection was more in primi gravida and second gravida. Pregnancy related complications in the form of preterm live births, intra-uterine death (IUD), still births and abortions were more in primi parous than multiparous patients. As the pregnancy is associated with increased incidence and adverse outcome of P.falciparum malaria infection, chemoprophylaxis should be made an integral part of antenatal care along with antianaemia therapy to reduce the risk of serious maternal and fetal complications.

Adult↗
PubMed1999

Management of celiac disease.

Celiac disease (CD), perceived as a rare cause of chronic diarrhea three decades ago, was diagnosed as a cause of diarrhea in 60 (7.5%) post weaned children among 800 cases of chronic diarrhea. The diagnosis was established on the basis of a detailed clinical history, histopathological studies on small bowel mucosa and a complete recovery on gluten free diets. Thirty four children were followed up for a period of 0.3 to 8.2 years (mean 3.45 +/- 2.28). Catch up growth was seen in all. A rapid gain in height and weight was observed in first year following exclusion of gluten from the diet. However, on subsequent follow up, flattening of growth curve was seen in 9 subjects which was attributed to non-compliance of gluten free diets and dietary inadequacies. Strict dietary compliance is difficult to adhere to with wheat being a staple cereal in India. Other factors affecting compliance include lack of awareness and non availability of gluten free diets as well as contamination of other items with wheat at grocery shops. A few cases may present as celiac crisis which is a medical emergency requiring aggressive management including use of corticosteroids to improve survival in this otherwise life threatening situation. Effective management of CD requires intense family cooperation as well as concerted national efforts to provide these patients easy access to gluten free diets. The evolution of Celiac Societies, and widespread dissemination of knowledge through all available media will greatly help in management of patients with this chronic disease.

Celiac Disease↗
PubMed1998

Repression of Stat3 activity by activation of mitogen-activated protein kinase (MAPK).

STAT proteins are activated by phosphorylation at specific tyrosine residue at the carboxy-terminus which is required for dimer-formation, nuclear translocation, DNA binding and transcriptional activity in cells treated with cytokines and growth factors. Recent studies have indicated that STATs are also phosphorylated by MAPK, or extracellular signal-regulated kinase (ERK) on serine. We investigated the role of ERK on the regulation of STAT activity. Here, we report that ERK2 activated by its upstream kinase, MEK1, represses Stat3 transcriptional activity induced by Src or Jak-2. To unravel the mechanism of repression, we further showed that Stat3 DNA binding activity and its tyrosine phosphorylation are also inhibited under the same conditions. ERK2 phosphorylates Stat3 on three serine-containing peptides and decreases its tyrosine phosphorylation induced by EGF treatment. We also detected an association of ERK2 and Stat3 in vivo which is modulated positively by activation of ERK2, but negatively by Jak2. We propose that MAP kinase cascade may negatively regulate Stat3 activities by decreasing its tyrosine phosphorylation and also possibly by association.

3T3 Cells↗
PubMed1998

Cortical connections of striate and extrastriate visual areas in tree shrews.

The ipsilateral and contralateral cortical connections of visual cortex of tree shrews (Tupaia belangeri) were investigated by placing restricted injections of fluorochrome tracers, wheat germ agglutinin-horseradish peroxidase, or biotinylated dextran amine into area 17 (V1), area 18 (V2), or the adjoining temporal dorsal area (TD). As previously reported, V1 was characterized by a widespread, patchy pattern of intrinsic connections; ipsilateral connections with V2, TD, and to a lesser extent, other areas of the temporal cortex; and contralateral connections with V1, V2, and TD. A surface-view of the myelin pattern in V1 revealed a patchwork of light and dark module-like regions. The ipsilateral connections with V2 and TD were roughly topographic, whereas heterotopic locations in V1 were callosally connected. Injections in V2 labeled as much as one third of V2 in a patchy pattern, and portions of ipsilateral V1 and TD in roughly topographic patterns. In addition, connections with several other visual areas in the temporal lobe were revealed. Contralaterally, most of the label was in V2, with some in V1 and TD. Injections in TD demonstrated connections within the region, and with adjoining portions of the temporal cortex, V2, and V1. There were sparse connections with an oval of densely myelinated cortex, which we have termed the temporal inferior area (TI). Callosal connections were concentrated in TD, but also included V2. The results provide further evidence for modular organizations within V1 and V2, and reveal for the first time the complete patterns of cortical connections of V2 and TD. The results are consistent with the proposal that at least three visual areas, the temporal anterior area, TA, the temporal dorsal area, TD, and the temporal posterior area, TP, exist along the rostrolateral border of V2 in tree shrews; suggest visual involvement of at least three other areas, the temporal inferior area, TI, the temporal anterior lateral area, and the temporal posterior inferior area located more ventrally in the temporal cortex; and fortify the conclusion that TD is the likely homologue of the middle temporal visual area of primates. Because tree shrews are considered close relatives of primates, the evidence for several visual areas along the border of V2 is more compatible with theories that propose a series of visual areas along V2 in primates, rather than a single visual area, V3.

Animals↗
PubMed1998

Stress-induced immediate-early gene, egr-1, involves activation of p38/JNK1.

The Ras/Raf/MAP kinase (ERK) pathway is a major signaling pathway induced by growth factors in mammalian cells. Two other types of mammalian MAP kinases, JNK (SAPK) and p38 (RK, CSBP), are induced by environmental stress. Although the immediate-early gene, egr-1, is induced by growth factors, cytokines, differentiation signals and DNA damaging agents, less is known about its induction by environmental stress and the mechanism involved. Here we report that in NIH3T3 cells, egr-1 is induced by various stress treatments such as heat shock, sodium arsenite, ultraviolet (U.V.) radiation, and anisomycin. p38 and JNK1, but not ERK2, were activated by these stress treatments. Induction of egr-1 by anisomycin is inhibited by a specific inhibitor of p38, SB 203580. We also show that p38 and JNK1 activated by their upstream kinases induce egr-1 promoter activity through activation of the ternary complex factor, Elk-1. The stress treatments also lead to an increase in Egr-1 protein phosphorylation and its DNA binding activity. Together, our data suggest that induction of egr-1 gene by growth factors and stress are mediated through different subgroups of MAP kinases which may also differentially affect egr-1 function on its target genes.

3T3 Cells↗
PubMed1998

Interactive case challenge. Dysphoric disorders in women: a case of premenstrual syndrome.

When this woman's long-standing PMS grows progressively more severe over the 3 years following the birth of her third child, what pharmacologic and nonpharmacologic treatments would you recommend? Symptoms of mood swings, irritability, and anxiety occur in many women during the premenstrual phase of the menstrual cycle. Several promising treatment options now exist for women whose symptoms are severe and interfere with daily functioning. These include nonpharmacologic as well as pharmacologic interventions, such as serotonergic antidepressants, anxiolytics, and hormones that suppress ovulation. When PMS becomes intolerably severe for this 36-year-old mother of 3 children--all under 10 years of age--she seeks treatment.

Adult↗
PubMed1997

Multiple divisions of macaque precentral motor cortex identified with neurofilament antibody SMI-32.

In brain sections stained with monoclonal antibody SMI-32, which recognizes non-phosphorylated neurofilament protein, we distinguished separate caudal, intermediate, and rostral subdivisions of gigantocellular precentral cortex (areas 4c, 4i, and 4r) in macaque monkeys. The divisions form bands extending mediolaterally across the major body-region representations of the primary motor cortex (M1). These observations provide additional evidence that primary motor cortex is not a single, structurally homogeneous cortical area.

Animals↗
PubMed1997

Deactivation and reactivation of somatosensory cortex after dorsal spinal cord injury.

Sensory stimuli to the body are conveyed by the spinal cord to the primary somatosensory cortex. It has long been thought that dorsal column afferents of the spinal cord represent the main pathway for these signals, but the physiological and behavioural consequences of cutting the dorsal column have been reported to range from mild and transitory to marked. We have re-examined this issue by sectioning the dorsal columns in the cervical region and recording the responses to hand stimulation in the contralateral primary somatosensory cortex (area 3b). Following a complete section of the dorsal columns, neurons in area 3b become immediately and perhaps permanently unresponsive to hand stimulation. Following a partial section, the remaining dorsal column afferents continue to activate neurons within their normal cortical target territories, but after five or more weeks the area of activation is greatly expanded. After prolonged recovery periods of six months or more, the deprived hand territory becomes responsive to inputs from the face (which are unaffected by spinal cord section). Thus, area 3b of somatosensory cortex is highly dependent on dorsal spinal column inputs, and other spinal pathways do not substitute for the dorsal columns even after injury.

Animals↗
PubMed1996

Casein kinase II associates with Egr-1 and acts as a negative modulator of its DNA binding and transcription activities in NIH 3T3 cells.

Although the activation domains within early growth response gene protein 1 (Egr-1) have been mapped, little is known of the kinases which phosphorylate Egr-1 and how phosphorylation correlates with the transcriptional activity of Egr-1. In this study we report that casein kinase II (CKII) co-immunoprecipitates with Egr-1 from NIH 3T3 cell lysates. The association of Egr-1 and CKII requires the C terminus of Egr-1 and CKII phosphorylates Egr-1 in vitro. The in vitro phosphorylation of Egr-1 by CKII and that induced by serum in vivo was compared by examining the CNBr-digested fragments of the phosphorylated Egr-1. CKII strongly phosphorylates fragments 7 and 10 which cover part of the activation/nuclear localization and DNA binding domains of Egr-1. CKII also phosphorylates, albeit weakly, fragments 5 and 8 which cover part of activation domain and the entire repression domain of Egr-1, respectively. Strong phosphorylation on fragment 10 as well as fragment 5 was also observed in Egr-1 immunoprecipitated from serum-induced, 32P-labeled cells. CKII phosphorylation of Egr-1 resulted in a decrease of its DNA binding as well as its transcriptional activities.

3T3 Cells↗
PubMed1996

Central reorganization of sensory pathways following peripheral nerve regeneration in fetal monkeys.

Transection of a sensory nerve in adults results in profound abnormalities in sensory perception, even if the severed nerve is surgically repaired to facilitate accurate nerve regeneration. In marked contrast, fewer perceptual errors follow nerve transection and surgical repair in children. The basis for this superior recovery in children was unknown. Here we show that there is little or no topographic order in the median nerve to the hand after median nerve section and surgical repair in immature macaque monkeys. Remarkably, however, in the same animals the representation of the reinnervated hand in primary somatosensory cortex area (area 3b) is quite orderly. This indicates that there are mechanisms in the developing brain that can create cortical topography, despite disordered sensory inputs. Presumably the superior recovery of perceptual abilities after peripheral nerve transection in children depends on this restoration of somatotopy in the central sensory maps.

Afferent Pathways↗
PubMed1996

Mechanisms of resistance of human small cell lung cancer lines selected in VP-16 and cisplatin.

BACKGROUND: The combination of VP-16 and cisplatin is one of the most active regimens available for the treatment of small cell lung cancer (SCLC), however, most tumors eventually become resistant to these drugs. METHODS: To investigate the problem of resistance to VP-16 and cisplatin in patients with SCLC, we established two resistant sublines from the drug sensitive human SCLC line, NCI-H209, by in vitro selection in VP-16 and cisplatin. RESULTS: The VP-16-selected cell line, H209/VP, was more than 100-fold resistant to VP-16, and displayed cross-resistance to VM-26 and other topoisomerase II interactive drugs, but not to vinca alkaloids. There was no difference in accumulation of VP-16 in H209/VP compared with its parent cell line. The level of topoisomerase II-alpha was reduced to 8% of that in the parent cell line, and there was an altered form of this enzyme with a molecular weight of 160 kilodaltons (kDa), in addition to the normal 170 kDa protein. The cisplatin-selected cell line, H209/CP, was 11.5-fold resistant to cisplatin, with only a low level of cross-resistance to other platinum compounds including carboplatin, tetraplatin, iproplatin, and lobaplatin. This line was highly cross-resistant to vinca alkaloids, but not to anthracyclines or epipodophyllotoxins. The H209/CP cell line was not resistant to cadium chloride, suggesting that alterations in metallothionein are unlikely to be a cause of resistance. Although glutathione (GSH) levels were increased nearly 2-fold in H209/CP, there was no difference in levels of the GSH-related enzymes glutathione-S-transferase, glutathione peroxidase, and glutathione reductase, compared with the parent line. The H209/CP line had a 1.4-fold elevation of topoisomerase II-alpha. The accumulation of cisplatin was reduced in this cell line, and there were fewer DNA-interstrand cross links formed in the presence of cisplatin in H209/CP, compared with the parent line. Neither H209/VP nor H209/CP expressed MDR1, the gene for P-glycoprotein. The MRP gene was expressed at a slightly higher level in the H209/VP cell line, but there was no significant increase in expression of this gene in the H209/CP cell line. CONCLUSIONS: The resistance of the H209/VP cell line is associated with an alteration of topoisomerase II-alpha, whereas the resistance in the H209/CP line is associated with reduced drug accumulation.

ATP Binding Cassette Transporter, Subfamily B, Mem↗