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Biomedical subjects

R Persaud

Publications and source records attributed to R Persaud.

At least 19 recordsLinked to original sources
PubMed1995

Why do psychiatrists neglect religion?

This paper analyses a number of possible reasons why modern psychiatry has neglected the therapeutic effects of religious beliefs. The gap which exists between psychiatry and religion is a relatively recent phenomenon and is partly related to psychiatry's progress in elucidating the biological and psychological causes of mental illness, rendering religious explanations superfluous. In addition, it is often assumed that religious attitudes are inevitably linked with phenomena such as dependence and guilt which are frequently seen as undesirable. Psychiatrists and psychologists tend to be less religiously orientated than their patients, which may further increase the professional's idea that religious beliefs are associated with disturbance. However, it has long been suspected that a positive relation exists between religion and mental health, and recently, the psychology of religion has provided empirical support for this idea. Psychiatry faces the challenge to accommodate this evidence into theory and practice.

Attitude of Health Personnel↗
PubMed1995

A pilot study of exposure control of chronic auditory hallucinations in schizophrenia.

BACKGROUND: Many patients complain less of their auditory hallucinations per se than of lack of control of the experiences. There is reason to believe that a non-distraction (exposure) approach could help patients gain more control over persistent auditory hallucinations and teach them that their experience is a form of thinking and has no external source. This study is a pilot test of that idea. METHOD: Five DSM-III-R schizophrenic outpatients with medication-resistant auditory hallucinations improved with a mean of 31 hour-long sessions over 3 months of therapist-guided exposure to their hallucinations and situations likely to evoke them. RESULTS: Improvement was greatest in patients' anxiety and sense of control over their hallucinations, less in social use of leisure and hallucinating time. CONCLUSIONS: These mildly encouraging pilot results warrant a controlled study of exposure for drug-resistant chronic auditory hallucinations and other psychotic experiences which are associated with anxious avoidance.

Anxiety↗
PubMed1994

Volumetric MRI measurements in bipolars compared with schizophrenics and healthy controls.

Twenty-six patients with RDC bipolar disorder were compared with a previously reported group of 48 RDC schizophrenics and 34 healthy controls, using volumetric MRI measurements of cerebral, cortical and sulcal volumes. The bipolar group appeared no different from the controls, and both of these groups had significantly larger cerebral and cortical volumes than the schizophrenics. Our previous report of a significantly reduced cortical volume in the schizophrenic group, with a corresponding increase in the volume of sulcal fluid is, therefore, not a generalized feature of psychotic illness but may be more specific to schizophrenia.

Adult↗
PubMed1994

Fractal analysis of the boundary between white matter and cerebral cortex in magnetic resonance images: a controlled study of schizophrenic and manic-depressive patients.

This paper reports development of a computerized ('box-counting') method for estimation of fractal dimension (FD) of the magnetic resonance image (MRI) boundary between cerebral cortex and white matter; and the application of this method to MRIs of 39 schizophrenics (SZs), 23 manic-depressives (MDs) and 31 controls (CONs). Mean FD across all diagnostic groups was 1.402; 95% confidence interval (CI) 1.399 to 1.406. Mean FD was greater in boundaries extracted from manic-depressive patients than in boundaries extracted from controls (difference between MD and CON mean FDs = 0.008; 95% CI -0.002 to +0.018); and less in schizophrenics than in controls (difference between SZ and CON mean FDs = -0.003; 95% CI -0.011 to +0.005). Mean FD was positively correlated with subcortical volume and anterior cerebral volume, and negatively correlated with sulcal cerebrospinal fluid volume. Significant differences in mean FD between diagnostic groups were demonstrated by analysis of covariance (ANCOVA; P < 0.01), with age and volumetric measures of brain size as covariates; and manic-depressive boundaries were shown to have significantly greater values for residual FD (after controlling for effects of brain size) than boundaries extracted from controls (t test; P < 0.05). It is proposed that FD is a useful measure of clinically relevant differences in the complexity of MRI boundaries.

Adult↗
PubMed1992

Use of running wheels regulates the effects of the ovaries on circadian rhythms.

Free-running circadian rhythms in core temperature, wheel-running and general locomotor activity were studied in ovariectomized or intact female rats housed with or without access to a running wheel. No differences in the monitored parameters were found between the intact and ovariectomized rats without a wheel. In the presence of a wheel, however, the intact rats differed from those that had been ovariectomized by displaying a shorter circadian period, an increased amplitude of the temperature rhythm, and strikingly higher rates of wheel-running and general locomotor activity. After estradiol treatment, the ovariectomized rats with a wheel developed a small increase in the temperature amplitude, and also in the correlation between wheel-running and general locomotor activity; these changes were not associated with a significant increase in wheel-running or a shortening of the circadian period. We conclude that some of the differences in circadian function between intact and ovariectomized rats are due to the differential use they make of running wheels, when available, and not directly attributable to the absence or presence of gonadal steroids.

Animals↗
PubMed1991

Lateralized anomalous perceptual experiences in schizophrenia.

Four cases of schizophrenia are described, in which subjects reported anomalous perceptual experiences confined to one visual field, in all cases the left visual field. The pattern, content and laterality of such anomalous perceptions point to the presence of right hemisphere dysfunction in schizophrenia. Further evidence to this effect comes from examining the type of anomalous perceptual experiences reported by subjects with focal lesions in either hemisphere. Those with right hemisphere damage but not those with left hemisphere damage report almost identical experiences to those seen in the 4 schizophrenics described here.

Adult↗
PubMed1989

Interaction of glycosylated human myelin basic protein with lipid bilayers.

Myelin basic protein (MBP), isolated from normal human myelin, was glycosylated with UDP-N-acetyl-D-galactosamine and a glycosyltransferase isolated from porcine submaxillary glands. MBP containing 0.85 mol of N-acetyl-D-galactosamine per mole of protein was oxidized at carbon 6 by galactose oxidase and complexed with a spin-label, Tempoamine, in order to study its interactions with lipids. When the spin-labeled MBP was reacted with lipid vesicles consisting of DSPG, DPPG, and DMPG, most of the spin-label was motionally restricted in the gel phase, with a correlation time greater than 10(-8)s. The motion increased with increasing temperature and was sensitive to the lipid phase transition. Interaction with the gel phase of DPPA caused much less motional restriction of the probe. However, melting of the lipid allowed increased interaction and motional restriction of the probe, which was only partially reversed on cooling back to the gel phase. The motional restriction of the probe in these lipids is attributed to its penetration partway into the lipid bilayer in both the gel and liquid-crystalline phases. The fact that the probe bound to the protein can penetrate partway into the bilayer suggests that other hydrophobic side chains and residues of the protein can similarly penetrate into the bilayer. Additional evidence for penetration was provided by digestion of the lipid-bound protein with endoproteinase Lys-C. When nonglycosylated and glycosylated MBP in solution was treated with Lys-C, extensive digestion occurred. A single radioactive peptide which eluted at 25 min was identified as residues 92-105.(ABSTRACT TRUNCATED AT 250 WORDS)

Glycosylation↗
PubMed1988

The glycosylation of human myelin basic protein at threonines 95 and 98 occurs sequentially.

Human myelin basic protein (MBP) was glycosylated by the enzyme, UDP-GalNAc:polypeptide N-acetylgalactosaminyl transferase (EC 2.4.2.41). A maximum of 1.7 mol of GalNAc was transferred to basic protein on threonines 95 and 98 of the protein. Proton NMR studies of basic protein glycosylated with 0.48-1.7 mol of GalNAc/mol of MBP showed that the order of addition to the two threonine residues is not random but sequential. The Thr-95 resonances shifted downfield, followed by the downfield shift of the Thr-98 resonances with increasing glycosylation. Since this peptide segment of the molecule is highly structured, conformational factors are probably responsible for this directed addition.

Amino Acid Sequence↗