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Biomedical subjects

A Roy

Publications and source records attributed to A Roy.

At least 325 records · Page 18Linked to original sources
PubMed1990

The natural occurrence of circulating antibodies in populations of endemic malarious areas.

The magnitude of humoral response to soluble antigen extracted from Plasmodium falciparum schizonts and merozoites was assessed in 744 blood samples collected from different parts of India. In this study, parasitological and immunological data were considered for assessment of antibody during natural infections at various seasons. The antibody response has been measured by enzyme-immuno assay. Survey was done in all age groups. Overall antimalarial IgG level had started increasing after five years which shows that the rate of infection was high in the small age groups. Elevated level of IgG in populations indicates that the study area is undergoing a period prevalence of the disease. In most of the individuals with active infection, IgG and IgM levels were high. Positivity in IgM denoted the active transmission of malaria. Elevated levels of antigen specific IgA was observed in some cases but the mechanism is not yet understood. Presence of circulating immune complexes during acute infection shows the failure of detection of circulating free antibodies in some individuals. The significance of findings in relation to serological status in individuals exposed naturally to malaria has been discussed.

Animals↗
PubMed1989

Coagulase-negative Staphylococcus sp septicemia in a lovebird.

Gram-positive cocci were observed within phagocytes in the blood of a psittacine with clinical signs of blindness and CNS disease. A coagulase-negative Staphylococcus sp was isolated from blood cultures, and the bird was successfully treated with chloramphenicol. Although the primary route of infection was not determined, the infection spread secondarily via the hematogenous route and localized intraocularly. Usually, only coagulase-positive strains of Staphylococcus are considered pathogenic, and are seldom diagnosed before death.

Animals↗
PubMed1989

Fluphenazine treatment reduces CSF somatostatin in patients with schizophrenia: correlations with CSF HVA.

CSF somatostatin and homovanillic acid (HVA) were measured in 14 schizophrenic patients while they were drug-free and during chronic fluphenazine treatment. CSF somatostatin was significantly reduced and CSF HVA was significantly elevated (p less than 0.002) during fluphenazine treatment. There was a trend toward correlation between CSF somatostatin and CSF HVA in the 14 schizophrenic patients when drug-free (r = 0.49, p less than 0.07) and fluphenazine-treated (r = 0.47, p less than 0.08). When examined in a larger group (n = 46) of drug-free schizophrenics, this relationship was highly significant (r = 0.59, p less than 0.001). These clinical data are consistent with preclinical evidence indicating a functional interaction between CNS somatostatin and dopamine systems.

Adult↗
PubMed1989

Suicidal behavior in depression: relationship to noradrenergic function.

We examined for relationships between suicidal behavior and noradrenergic function in depression. We compared depressed patients who had or had never attempted suicide and controls on cerebrospinal fluid, plasma, and urinary indices of noradrenergic function. There was no consistent pattern of significant findings in relationship to depressed patients who had attempted suicide. Thus, these essentially negative results suggest that the noradrenergic system is probably not a major determinant of suicidal behavior in depressed patients.

Adult↗
PubMed1989

Cerebrospinal fluid monoamine metabolites and suicidal behavior in depressed patients. A 5-year follow-up study.

We carried out a 5-year follow-up study of suicidal behavior among depressed patients who earlier had determinations of cerebrospinal fluid levels of monoamine metabolites. Patients who reattempted suicide during the follow-up had significantly lower cerebrospinal fluid levels of both the serotonin metabolite 5-hydroxyindoleacetic acid and the dopamine metabolite homovanillic acid. The findings were most striking among melancholic patients. These follow-up results suggest that reduced central turnover of serotonin and dopamine may be associated with further suicidal behavior among depressed patients who have previously attempted suicide.

Adult↗
PubMed1989

Extraversion in pathological gamblers. Correlates with indexes of noradrenergic function.

Pathological gamblers may have a disturbance of their central nervous system noradrenergic functioning. We administered the Eysenck Personality Questionnaire to pathological gamblers and examined relationships between their personality scores on this questionnaire and indexes of noradrenergic function. There were highly significant correlations between scores on the extraversion scale and cerebrospinal fluid levels of 3-methoxy-4-hydroxyphenylglycol, plasma levels of 3-methoxy-4-hydroxyphenylglycol, urinary outputs of vanillylmandelic acid, as well as with the sum of urinary outputs of norepinephrine and its major metabolites. These results suggest that the disturbance in the central noradrenergic system in pathological gamblers may be partly reflected in their personality.

Adult↗
PubMed1989

Comparative study on coagulant, defibrinating, fibrinolytic and fibrinogenolytic activities of Costa Rican crotaline snake venoms and their neutralization by a polyvalent antivenom.

The coagulant, defibrinating, fibrino lytic and fibrinogenolytic activities of venoms from ten species of Costa Rican crotaline snakes were studied, together with the neutralization of these effects by a polyvalent antivenom. The venoms of Bothrops asper, B. schlegelii, B. nummifer, B. godmani, Lachesis muta and Crotalus durissus induced a coagulant effect in vitro, and all of them, with the exception of B. nummifer, also induced defibrination in vivo. The four non-coagulant venoms (B. lateralis, B. ophryomegas, B. nasuta and B. picadoi) induced a degradation of the alpha (A) chain of fibrinogen, thereby inhibiting coagulation. However, they did not induce defibrination upon i.v. injection. All of the venoms showed fibrinolytic activity in vitro. Polyvalent antivenom was effective in the neutralization of coagulant, defibrinating, fibrinolytic and fibrinogenolytic activities of these venoms, with the exception of coagulant effect induced by C. durissus venom. Since only three venoms are used in the immunization of horses, these results demonstrate the high degree of immunological cross reactivity between components affecting coagulation in Costa Rican crotaline snake venoms.

Animals↗
PubMed1989

Specificity of plasma HVA response to dexamethasone in psychotic depression.

Earlier reports have suggested that dexamethasone significantly increases levels of plasma homovanillic acid (HVA) in normal subjects, but that this effect may be altered in some depressed patients. To investigate the specificity of such alterations, we administered dexamethasone (1 mg p.o. at 11 p.m.) to 33 normal subjects, 27 depressed patients (8 with psychotic features), and 16 schizophrenic patients. Plasma for assay of cortisol and HVA was obtained at 4 p.m. before and on the day following dexamethasone administration. Dexamethasone induced significant increases in plasma HVA in the normal subjects and in the schizophrenic patients, but not in the depressed patients. Indeed, psychotically depressed patients tended to show a dexamethasone-associated decrease in plasma levels of HVA. In contrast to cortisol "suppression" or "nonsuppression," dexamethasone-induced changes in plasma levels of HVA (i.e., increases or decreases) sensitively and specifically discriminated between patients with affective and nonaffective psychoses.

Adult↗
PubMed1989

CSF GABA and neuropeptides in pathological gamblers and normal controls.

We previously reported that pathological gamblers may have increased central noradrenergic activity. Neurons releasing gamma-aminobutyric acid (GABA) are known to be a part of an inhibitory system regulating the activity of central noradrenergic neurons. Therefore, we examined cerebrospinal fluid (CSF) levels of GABA in pathological gamblers and normal controls. There was no significant difference between the groups. Also, depressed and nondepressed gamblers did not differ significantly in their CSF levels of GABA. Among controls, however, there was a significant negative correlation between CSF levels of GABA and the norepinephrine metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) and a significant positive correlation between CSF levels of GABA and corticotropin releasing hormone (CRH). Also, CSF levels of CRH showed a significant positive correlation with CSF levels of adrenocorticotropic hormone in both pathological gamblers and controls.

Adult↗
PubMed1989

Platelet adrenoceptors and prostaglandin responses in depressed patients.

Platelet alpha 2-adrenergic receptor binding and prostaglandin responsivity were measured in depressed patients. Depressed patients had significantly higher platelet 3H-dihydroergocryptine (3H-DHE) binding values than controls. Depressed patients also showed significantly reduced prostaglandin E1-stimulated cyclic adenosine 3',5'-monophosphate (cAMP) production and significantly decreased % inhibition of cAMP production by norepinephrine. These results support the suggestion that there may be a dissociation between alpha 2-adrenergic receptor binding and responsivity in depression. There were no significant correlations between platelet adrenergic variables and other indices of noradrenergic function. However, there was a significant correlation between 3H-DHE binding values and basal plasma levels of cortisol.

Adult↗
PubMed1989

CSF studies on alcoholism and related behaviours.

1. A defect in central serotonin metabolism may manifest itself in poor impulse control leading to attempts at suicide, violence towards others, and Type II alcohol abuse. 2. Studies reporting negative associations between low CSF levels of the serotonin metabolite 5-HIAA and personality traits of aggressiveness and hostility are reviewed. 3. We also studied pathological gamblers. They showed significantly increased central noradrenaline metabolism, perhaps related to sensation seeking.

Alcoholism↗
PubMed1989

Isolation and characterization of the gene encoding the beta-subunit of rat follicle-stimulating hormone.

Follicle-stimulating hormone (FSH) is a pituitary glycoprotein hormone that is comprised of two dissimilar subunits, alpha and beta, encoded by separate genes. We have isolated the gene encoding the beta-subunit of rat FSH by screening a rat genomic DNA-library by filter hybridization with bovine FSH-beta cDNA. Southern blot analysis of rat genomic DNA suggests that there is a single copy of the FSH-beta gene per haploid genome in the rat. The nucleotide sequence of the rat FSH-beta gene was determined and the amino acid sequence of the subunit was deduced. The gene is composed of three exons and two introns. The predicted amino acid sequence reveals that there is a 20-amino-acid signal peptide followed by a mature protein of 110 amino acid residues. Exons I, II, and III are 36, 187, and 1221 bp, respectively. Intron 1 (640 bp) interrupts the 5'-untranslated (UT) region (61 bp) and intron 2 (approximately 1 kb) interrupts the coding region between amino acid residues +34 and +35. Comparison of the amino acid sequence to those of the human and bovine FSH-beta subunits reveals 80% similarity to both species. The "CAGY" sequence, or the Cys-Ala-Gly-Tyr quartet of amino acids encoded by exon II is present in every other glycoprotein beta-subunit sequenced thus far, is altered in rat FSH-beta, with the Ala residue replaced by Glu. Primer extension analysis demonstrated that there is a single transcriptional start site. The nucleotide sequence of the 5'-flanking region (1 kb) was determined and compared to the nucleotide sequences of corresponding regions in the bovine and human genes. This analysis revealed that there are three regions in the 5'-flanking region of the rat FSH-beta gene that display greater than 80% sequence similarity to regions in the bovine and human genes. The second of these regions also shares similarity to segments within the 5'-flanking regions of the rat alpha- and LH beta-subunit genes. The characterization of the rat FSH-beta gene will enable further study of the regulation of rat FSH using in vitro systems.

Amino Acid Sequence↗
PubMed1989

Nutritional factors in diabetics with and without retinopathy.

We used 3-d food-record-keeping techniques to examine nutritional factors in diabetic patients with and without retinopathy. Patients without retinopathy had significantly higher daily intakes of total carbohydrate, water-soluble dietary fibers, insoluble dietary fibers, and glucose than did patients with retinopathy. Also, patients without retinopathy took a significantly lower proportion of their total daily calories as protein.

Adult↗
PubMed1989

Bone imaging after cementless press fit total hip arthroplasty.

In view of the high rate of loosening of conventional cemented hip prostheses, cementless implants are gaining popularity in Europe and North America. Smooth-surfaced "press fit" prostheses are designed for autolocking in the femoral canal at the time of installation. Fifteen patients were prospectively followed by bone imaging with Tc-99m MDP at three-month intervals after cementless "press fit" hip arthroplasty to define the "normal" distribution of mechanical stress to the surrounding bone, as well as the incorporation of bone allografts used for reconstruction of resorption sites in cases of revision surgery.

Adult↗
PubMed1989

Personality factors and pathological gambling.

Pathological gambling is a disorder in which personality factors are thought to be important. Therefore, we compared 19 male pathological gamblers with 18 male normal controls for their scores on 3 personality questionnaires. Pathological gamblers were found to have significantly higher psychoticism and neuroticism scores on the Eysenck Personality Questionnaire than controls. Gamblers also had significantly higher total hostility scores on the Hostility and Direction of Hostility Questionnaire. The possible implications of these findings are discussed.

Adult↗