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Biomedical subjects

A Mathur

Publications and source records attributed to A Mathur.

At least 91 records · Page 5Linked to original sources
PubMed1994

Radiological and neurophysiological changes in Japanese encephalitis.

Six patients with Japanese encephalitis, four males and two females whose age ranged between 2 and 47 years, were subjected to neurophysiological and radiological studies. An EEG in five of the patients showed diffuse delta wave activity and one had an alpha coma. Delta activity seems to be due to thalamic involvement, which was seen on CT of two and MRI of all the patients. The thalamic lesions were characteristically bilateral and were haemorragic in five. Changes on MRI included abnormalities of the brainstem in three and the basal ganglia and spinal cord in one patient each. Lower motor neuron signs were present in three patients but abnormal MRI signals in the spinal cord were present in only one out of three patients in whom spinal MRI was carried out. Central motor conduction time in the upper limb was prolonged in three patients (five sides) and in the lower limbs in one (both sides), which was consistent with involvement of the cerebral cortex, thalamus, brainstem, and spinal cord. Changes in MRI and EEG in the acute stage may provide early diagnostic clues in patients with Japanese encephalitis.

Acute Disease↗
PubMed1994

Clinical predictors of Japanese encephalitis.

Over a 5-year period, virological investigations for Japanese encephalitis (JE) were conducted in children presenting with acute encephalopathic illness. Clinical features of JE-positive patients (n = 116) were compared with patients in whom the diagnosis could be excluded (n = 57). Multivariate analysis by logistic regression revealed that two clinical signs--central hyperpneic breathing pattern and extrapyramidal signs--were significant predictors of the diagnosis. Application of the model yielded a sensitivity of 41.3% and a specificity of 80.7% with positive and negative predictive values of 81.3 and 40.3%, respectively. This indicates that the model may be helpful in making the diagnosis but not in excluding it. The model should be further validated in different areas where the disease is prevalent.

Child↗
PubMed1994

Role of calcium in neutrophil activation by Japanese encephalitis virus-induced macrophage derived factor.

The role of cytosolic Ca2+ concentration in neutrophils stimulated with macrophage derived neutrophil chemotactic factor (MDF) produced following Japanese encephalitis virus (JEV) infection in mice was correlated with cell functions. MDF-induced Ca2+ influx from extracellular milieu and release from intracellular store resulted in rise of cytosolic Ca2+ in a dose-dependent manner and was independent of protein kinase C. Macrophages and B cells did not show cytosolic Ca2+ changes while T lymphocytes showed slight rise when stimulated with MDF. Neutrophil chemotaxis in the absence of Ca2+ was slightly different from that in presence of Ca2+. Pretreatment of neutrophils with 3,4,5-trimethoxy-benzoic acid-8-(diethylamine)-octylester (TMB-8) inhibited the chemotaxis. It was observed that superoxide production and degranulation by neutrophils after stimulation with MDF was not dependent on the presence of extracellular calcium, but stripping of intracellular calcium resulted in abrogation of neutrophil activation. Thus, mobilization of intracellular calcium seems to be necessary for neutrophil activation by MDF.

Alkaloids↗
PubMed1994

Lymphoproliferative disorders and other tumors complicating immunodeficiencies.

Lymphoproliferative disorders and selected carcinomas which occur as complications of primary or secondary immunodeficiencies are frequently fatal. The incidence rates of these cancers vary from 1% to as high as 25% among specific groups of persons with primary (genetically-determined) immunodeficiencies as well as acquired immunodeficiencies, including immunosuppressed organ transplant recipients and individuals infected with HIV. Lymphoproliferative disorders including Epstein Barr virus (EBV) associated B cell lymphoproliferative disease (BLPD) and Hodgkin's disease represent the predominant category of tumors in both primary and acquired immunodeficiencies. EBV is an important cofactor common to many, but not all, B cell "lymphomas." Immunodeficient individuals who are at risk for developing EBV BLPD may demonstrate both inadequate immune responses to the virus as well as generalized immunoregulatory dysfunction reflected as imbalances in cytokine production favoring the proliferation of transformed B lymphocytes. Historically, the success of treatment of lymphoproliferative disorders in immunodeficiencies with conventional multi agent chemotherapies and/or radiation has been limited by unfavorable tumor response rates and high morbidity and mortality related to intercurrent opportunistic infections. With improvements in supportive care and the use of recombinant biologic response modifiers such as alpha interferon and/or other immunotherapies to treat EBV BLPD, survival of immunodeficient hosts following tumor diagnosis may improve. In addition to lymphoproliferative disorders, patients with congenital immunodeficiencies associated with IgA deficiency (including ataxia telangiectasia and Common Variable Immunodeficiency) are at increased risk for gastrointestinal carcinomas. Early detection and surgical excision of such tumors can result in prolonged survival in such patients.

Humans↗
PubMed1993

Thrombin-fibrinogen interaction: pH dependence and effects of the slow-->fast transition.

A recently developed strategy capable of measuring the equilibrium dissociation constant for thrombin-fibrinogen interaction has been used to explore the pH dependence of the interaction and the effects of thrombin conformational transitions. The dependence of fibrinogen binding to thrombin in the pH range 6-10 is bell-shaped and remarkably similar to that obtained in the case of the small synthetic amide substrate tosyl-Gly-Pro-Arg-p-nitroanilide-AcOH. Since the synthetic substrate contains no groups that can ionize in the pH range 6-10, the bell-shaped curve must reflect ionization reactions of two groups of the enzyme with pK1 = 7.53 +/- 0.09 and pK2 = 8.80 +/- 0.09. These groups can be identified as the catalytic histidine, His57, and the amino terminus of the B chain, Ile16, respectively. Deprotonation of His57 in the acidic region is important for optimal binding, while protonation of Ile16 in the alkaline region is critical for the formation of a salt bridge with Asp194, which guarantees the conformational stability of the enzyme. The loss of binding free energy at low (< 7.0) and high (> 9.0) pH values is linked to protonation of His57 and deprotonation of Ile16, respectively. The first 51 residues of the A alpha chain of fibrinogen are known to be necessary and sufficient for optimal recognition by thrombin, but none of them contributes to the pH dependence of fibrinogen binding in the pH range examined. Hence, the two possible ionizable groups of the A alpha chain, i.e., the amino terminus Alal and His24, make no contacts with the thrombin surface.(ABSTRACT TRUNCATED AT 250 WORDS)

Acylation↗
PubMed1993

Rewarding brain stimulation: role of tegmental cholinergic neurons that activate dopamine neurons.

Cholinergic neurons of the pedunculopontine nucleus (Ch5) are believed to monosynaptically excite ventral tegmental dopamine neurons. Muscarinic blockers injected near dopamine cells block the rewarding effect of hypothalamic or dorsal tegmental rewarding brain stimulation (RBS) in rats. Because Ch5 cells are inhibited by muscarinic agonists, we injected muscarinic drugs unilaterally near Ch5 neurons to inhibit or disinhibit them. Carbachol raised thresholds for hypothalamic self-stimulation bilaterally by over 400%, whereas scopolamine reduced thresholds by 20%-80%. Pretreatment with either carbachol or scopolamine blocked the effect of the other drug, which suggests that both acted through the same receptors near Ch5 cells. Therefore, activation of Ch5 neurons is critical for hypothalamic RBS. A mechanism for the involvement of Ch5 neurons in drug rewards and antimuscarinic psychosis is also proposed.

Animals↗
PubMed1993

Marital adjustment and subjective well-being in Indian-educated housewives and working women.

We compared marital adjustment and subjective well-being in Indian-educated housewives (N = 200) and working women (N = 200) who were administered a Marital Adjustment Questionnaire (Kumar & Rastogi, 1976) and 10 measures of subjective well-being (Warr, 1984). Results indicated significantly better marital adjustment and subjective well-being for the working women than for the housewives. Specifically, working women reported higher scores on general health, life satisfaction, and self-esteem measures and lower scores on hopelessness, insecurity, and anxiety, compared with the housewives, although the housewives had lower scores on negative affect than the working women. Findings were insignificant on positive affect and depression.

Adaptation, Psychological↗
PubMed1993

Immunopathology, musculoskeletal features, and treatment of sarcoidosis.

Sarcoidosis is a clinical expression of intricate immune events. Firm evidence exists that unchecked helper T-cell proliferation restricted to the site of disease activity is the pivotal aberration. Alveolar macrophages from patients with sarcoidosis have been observed to release high levels of tumor necrosis factor-alpha and interleukin-2 and to exhibit enhanced expression of leukocyte function antigen 1 and intercellular adhesion molecule 1. These cytokines and adhesion molecules could result in compartmentalized T-cell proliferation at certain sites of disease. A new marker, serum procollagen type III-derived peptide, is reported to correlate with disease activity. Arthrosonography revealed periarticular edema as the prime pathologic process in the acute sarcoid reaction. Magnetic resonance imaging has greater diagnostic utility than does computed tomography in sarcoid myopathy. The acute sarcoid reaction is associated with a distinct HLA type and resolves spontaneously in 1 to 6 months. Chronic sarcoid arthritis causes destructive and deforming changes that rarely can be akin to Jaccoud's type arthropathy. Muscle and osseous disease is rare and asymptomatic. Nonsteroidal anti-inflammatory drugs and corticosteroids are the mainstays of pharmacotherapy. Deflazacort is an effective and safe steroid preparation with a lesser incidence of osteoporosis when used for long periods.

Humans↗
PubMed1993

Reduced postprandial cholecystokinin (CCK) secretion in patients with noninsulin-dependent diabetes mellitus: evidence for a role for CCK in regulating postprandial hyperglycemia.

The plasma cholecystokinin (CCK) response to a test meal was studied in 16 control subjects and 15 patients with noninsulin-dependent diabetes mellitus (NIDDM). Basal CCK levels were approximately 1 pmol in both groups. However, after the test meal, plasma CCK levels were 2-fold greater in the controls when compared to the diabetics. In controls, CCK levels maximally increased by 5.6 +/- 0.8 pmol (mean +/- SEM) 10 min after feeding, whereas in the NIDDM patients this value was 1.9 +/- 0.6 pmol (P < 0.001). After the test meal, the normal subjects showed no postprandial rise in blood glucose, whereas the diabetic patient showed a rise of 2.6 +/- 0.7 mmol. To determine whether the decreased CCK levels may have been related to the postprandial hyperglycemia, 7 diabetic subjects were infused with CCK. With this CCK infusion, postprandial glucose levels did not rise. These data suggest, therefore: 1) a role for cholecystokinin in regulating postprandial hyperglycemia in man, 2) abnormalities in CCK secretion occur in NIDDM and may contribute to the hyperglycemia seen in this disease.

Adult↗
PubMed1993

Autonomic and peripheral neuropathy in insulin dependent diabetics.

Twenty five diabetics (all insulin dependent) and 20 age and sex matched controls were studied to assess peripheral nerve functions and autonomic (cardiovascular and urinary bladder) nerve functions. Impotence was the commonest symptom followed by postural dizziness, atonic bladder, shooting pains in the limbs and gustatory sweating. Cardiac autonomic neuropathy was found in 60% of the diabetics while 68% of them had diabetic cystopathy. Peripheral nerve dysfunction was present in 80% of the patients. Forty percent of the diabetics had all the three forms of neuropathies (cardiac, urinary bladder and peripheral), while another 40% of the patients had at least two forms of neuropathy.

Adult↗
PubMed1993

Clinical sequelae of Japanese encephalitis in children.

Over a five and a half year period, virological investigations for Japanese encephalitis (JE) were conducted in children admitted with acute encephalitis like illness to a large city hospital. The diagnosis of Japanese encephalitis was made by viral isolation from cerebrospinal fluid and/or a four-fold or higher rise in haemagglutination inhibiting antibodies in paired sera followed by demonstration of specific IgM antibodies by HI test after treatment with 2-mercapto ethanol. All children surviving the illness were contacted by post and followed up for sequelae. A total of 55 children could be followed up after 12-18 months and 22 of these even after 2 yr. A high rate of major sequelae (45.5%) in the form of frank motor deficits (32.7%), mental retardation (21.8%) and/or convulsions (18.2%) was observed. Neurological deficits were of diverse types and improved even after 2 yr of the illness. Fourteen patients (25.4%) had only minor deficits in the form of scholastic backwardness, behavioural problems and/or subtle neurological signs. Only 16 (29.2%) patients were completely normal on follow up. JE may therefore be an important cause of neurological handicap in this area. Sequelae of the disease were more severe if the initial illness was prolonged (P < 0.001, CI 2.45, 12.64), or associated with focal neurological deficits (P < 0.001, CI 1.97, 7.02).

Child↗
PubMed1993

Stimulation of neutrophil respiratory burst and degranulation by Japanese encephalitis virus-induced macrophage derived factor.

The effects of Japanese encephalitis virus (JEV) and JEV-induced macrophage derived neutrophil chemotactic factor (MDF) on respiratory burst and granule exocytosis in neutrophils were studied and were compared with N-formyl-methionyl-leucyl-phenylalanine (FMLP). JEV-stimulated neutrophils released reactive oxygen metabolites with maximum activity between days 7 and 9. The response in mice was sensitive to anti-JEV-antisera treatment. Stimulation by MDF resulted in quick release of superoxide and granule enzymes from neutrophils upon both in-vivo and in-vitro stimulation in a dose dependent manner. The effect was abrogated by the MDF-specific antisera treatment. These responses were similar in kinetics and magnitude to those produced in response to FMLP. The respiratory burst elicited by MDF was abrogated by staurosporine, indicating that neutrophil activation and signal transduction by MDF and FMLP are dependent on protein kinase C.

Alkaloids↗
PubMed1992

Primary immunodeficiencies: genetic risk factors for lymphoma.

It has been estimated that up to 25% of patients with certain genetically determined immunodeficiencies will develop tumors, primarily B-cell lymphomas, during their lifetime. Epstein-Barr virus appears to be an important cofactor in the development of lymphoproliferative disorders in patients with primary immunodeficiencies, as well as acquired immunodeficiencies. Additionally, host defects in immunoregulation and/or gene rearrangement, which are features of certain primary immunodeficiencies, probably contribute to the risk of lymphomagenesis in patients at risk.

Adolescent↗
PubMed1992

Use of the computed tomographic scan in Japanese encephalitis.

Fourteen children with laboratory-confirmed Japanese encephalitis were given cranial computed tomographic (CT) scans six to 30 days after the onset of illness. The findings were variable; there was a generalized decrease in attenuation values, three patients showed features of cerebral atrophy, and four others had normal scans. The findings appeared to relate to both the severity and the stage of the illness at the time the scans were made. CT would appear to be of little use in making a specific diagnosis of Japanese encephalitis.

Brain↗