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Biomedical subjects

R Mahendran

Publications and source records attributed to R Mahendran.

67 records · Page 4Linked to original sources
PubMed1992

The effects of paroxetine, alone and in combination with alcohol on psychomotor performance and cognitive function in the elderly.

Fifteen healthy male volunteers aged over 60 years received acute and repeated doses of paroxetine 20 mg or placebo, and acute doses of lorazepam 1 mg (as a positive internal control) with or without alcohol (0.6 g/kg of body weight) administered openly in a double blind balanced crossover study in which each subject acted as his own control. Psychomotor performance and cognitive function were assessed using a test battery which included critical flicker fusion, choice reaction time, compensatory tracking, Stroop and memory scanning tests. Subjective ratings of mood and sleep were recorded using line analogue rating scales. The pattern of results indicated that paroxetine had little or no effect on most of the test variables, and in some instances (critical flicker fusion thresholds) improved information processing ability. This was in marked contrast to the lorazepam verum which produced sedation and disruption of performance. Paroxetine had a slight antagonistic effect on alcohol induced sedation whereas impairment of performance with lorazepam was potentiated by co-administration of alcohol. The low behavioural toxicity of paroxetine in elderly volunteers has important implications for the pharmacotherapy of depression.

Aged↗
PubMed1991

RNA editing by cytidine insertion in mitochondria of Physarum polycephalum.

A corollary of the central dogma of molecular biology is that genetic information passes from DNA to RNA by the continuous synthesis of RNA on a DNA template. The demonstration of RNA editing (the specific insertion, deletion or substitution of residues in RNA to create an RNA with a sequence different from its own template) raised the possibility that in some cases not all of the genetic information for a trait residues in the DNA template. Two different types of RNA editing have been identified in mitochondria: insertional editing represented by the extensive insertion (and occasional deletion) of uridine residues in mitochondrial RNAs of the kinetoplastid protozoa and the substitutional editing represented by the cytidine to uridine substitutions in some plant mitochondria. These editing types have not been shown to be present in the same organism and may have very different mechanisms. RNA editing of both types has been observed in nonmitochondrial systems but is not as extensive and may involve still different mechanisms. Here we report the discovery of extensive insertional RNA editing in mitochondria from an organism other than a kinetoplastid protozoan. The mitochondrial RNA apparently encoding the alpha subunit of ATP synthetase in the acellular slime mould, Physarum polycephalum, is edited at 54 sites by cytidine insertion.

Amino Acid Sequence↗
PubMed1990

Mitochondrial DNA of Physarum polycephalum: physical mapping, cloning and transcription mapping.

Mitochondrial DNA (mtDNA) has been isolated from four strains of Physarum polycephalum and a restriction site map has been determined using nine restriction enzymes. The restriction site maps of the four strains are similar but each strain is distinguished by insertions, deletions and restriction enzyme site polymorphisms. The sum of the restriction fragments gives mitochondrial genome sizes which vary from about 56 kb to 62 kb. In all four strains the composite map of the restriction enzyme sites for the mtDNA is circular. Knowledge of the restriction enzyme map has enabled cloning of mtDNA fragments representing the entire mtDNA of strain M3. The cloned fragments have been used to create a transcription map of the mtDNA.

Blotting, Northern↗
PubMed1990

A follow-up study of Asian problem drinkers.

This is a follow-up study of 70 patients referred for treatment of drinking problems. At the end of 12 months, it was found that 60% remained in abstinence, 8.5% social drinking, 28.5% relapsed or defaulted and 3% died. A poor outcome was observed in patients between 20 and 39 years old as compared to those between 40 and 59 years old. Patients with SADQ scores of less than 20 had good outcomes. However, there was no significant difference between Indian and Chinese patients. Marital status and social class were not useful predictors of outcome.

Adult↗
PubMed1989

Expression of the common acute lymphoblastic leukaemia antigen (CALLA) in the human breast.

A biochemical and immunohistological study has been carried out to characterize the antigen in human breast reacting with antibodies to the common acute lymphoblastic leukaemia antigen (CALLA). Four different monoclonal antibodies to the CALLA antigen all stain the membrane of adult human myoepithelial cells. Surface labelling studies of freshly prepared human breast cells demonstrate that the anti-CALLA antibody, J5, immunoprecipitates a 100 kDa protein that co-electrophoreses with the CALLA antigen identified in the leukaemia cell line NALM-6. These results indicate that the CALLA antigen is expressed on myoepithelial cells and that the staining is not due to reactivity with a shared epitope on an unrelated molecule.

Antibodies, Monoclonal↗
PubMed1989

Psychiatric complications of Erimin abuse.

Nimetazepam (Erimin) is a benzodiazepine which has become a new drug of abuse in Singapore. Three cases presenting with psychiatric complications had been treated as inpatients over a period of one and a half years (1986 to 1987) in Woodbridge Hospital and Tan Tock Seng Hospital. Their clinical presentations which included drug dependency, withdrawal psychosis and transient drug psychosis are described and discussed.

Adult↗
PubMed1986

Identification of myoepithelial cells in human and rat breasts by anti-common acute lymphoblastic leukemia antigen antibody A12.

An immunohistological study in the human breast and the rodent breast (from inbred Ludwig/Wistar/Olac rats) was conducted with the use of a murine monoclonal antibody, which reacts with the common acute lymphoblastic antigen, a glycosylated polypeptide of a molecular weight of 100,000. The epitope, as recognized by this antibody, is expressed on myoepithelial cells of the normal human and rat breasts and was studied in the developing rodent mammary gland. Ultrastructural studies in the normal human breast clearly demonstrated the presence of the antigen on the lateral membrane of the myoepithelial cells with no staining of luminal cells, blood vessels, or stromal elements. The antigen survived prolonged enzymatic digestion of human breast tissue and could be demonstrated on myoepithelial cells in single-cell suspensions of human breast where it stained approximately 3-14% of the total cell population. The presence of this antigen on myoepithelial cells is discussed in the context of myoepithelial differentiation in the breast and the potential utility of the antibodies for cell separation.

Animals↗