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Biomedical subjects

T J Crow

Publications and source records attributed to T J Crow.

At least 199 records · Page 11Linked to original sources
PubMed1987

Integrated viral genes as potential pathogens in the functional psychoses.

According to the retrovirus-transposon hypothesis, psychosis is due to the expression of a pathogenic sequence (a "virogene") integrated in the genome and either inherited from an affected or predisposed parent or acquired in the course of reproduction by a genetic rearrangement (e.g. a transposition or the generation of a tandem repeat). The psychoses are viewed as a continuum extending from unipolar through bipolar and schizo-affective disorder to schizophrenia with increasing severity of defect, movement along this continuum occurring by such genetic rearrangements. The locus at which these changes take place is envisaged as related to the genetic determinants of cerebral lateralisation (the "cerebral dominance gene") the interaction between potential pathogen and growth factor gene having possible growth enhancing effects. Such beneficial effects may have ensured the survival of this "hot-spot" in the genome.

Diseases in Twins↗
PubMed1987

Mutation and psychosis: a suggested explanation of seasonality of birth.

The persistence of psychosis at a high and relatively constant prevalence in the various populations of the world is rendered difficult to explain by the absence of identified environmental precipitants and by reduced fertility of affected individuals. The problem is not confined to schizophrenia but applies also to affective disorder. The 'virogene' concept attempts to explain this paradox as follows. (1) Psychosis in general is, as suggested by Böök (1953) and Lewis (1958) for schizophrenia, associated with a high rate of mutation. (2) The new mutations occur at a specific site (a 'hot-spot') in the genome and consist of rearrangements (e.g. transpositions or new insertions occurring as a result of unequal recombination) in a sequence which has a degree of potential autonomy, i.e. an integrated pathogen or 'virogene'. (3) The mutations occur specifically in the courses of gametogenesis in the male. By its location in the scrotal sac and its extended time course, gametogenesis in the male is susceptible to insertional mutagenesis as a function of variations in environmental temperature. Such temperature-dependent mutations are reflected in the seasonality of birth seen in both schizophrenic and affective illnesses. The increased likelihood of such mutations occurring with time is held to account for the association of psychosis with increased paternal age. (4) Such new events are held responsible not only for 'sporadic' cases in individuals without a family history of psychosis, but also for increases in severity of illness between generations. Psychosis is viewed as a continuum extending from unipolar through bipolar affective disorder and schizoaffective illness to schizophrenia with increasing degrees of defect.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1987

The occurrence of organic disease of possible or probable aetiological significance in a population of 268 cases of first episode schizophrenia.

In a sample of 268 cases of first-episode schizophrenia, 15 patients were found to have organic disease which appeared relevant to the mental state. There were three cases of syphilis, two cases of sarcoidosis, three of alcohol excess and two of drug abuse. There was one case each of carcinoma of the lung, autoimmune multisystem disease, cerebral cysticercosis, thyroid disease and previous head injury. In this series, identified organic disease was associated with less than 6% of cases of schizophrenia.

Adolescent↗
PubMed1987

A comparison of some retrograde and anterograde effects of electroconvulsive shock in patients with severe depression.

Seventy severely depressed patients were randomly assigned to receive either a standard course of bilateral electroconvulsive therapy (ECT) or a course of simulated ECT (muscle relaxant and anaesthesia) identical to the real course except that the shock was omitted. Anterograde amnesia due to the shock was demonstrated in recognition memory for word lists and in recall of labels for faces, but this was eliminated by priming. Retrograde amnesia was also present for labels for faces learned the day before a treatment, but this was not eliminated by priming. Recognition memory for material learned in the remote past was better in the patients who had received shock than in those who had received only anaesthetic.

Adult↗
PubMed1987

Search for viral nucleic acid sequences in the post mortem brains of patients with schizophrenia and individuals who have committed suicide.

Molecular hybridisation has been used to screen several areas of post mortem brain from 20 patients with schizophrenia, 23 individuals who were suspected of having committed suicide and 21 control cases, for viral nucleic acids. Cloned probes were able to detect picogram levels of viral DNA and to quantify herpes simplex type 1 DNA from encephalitic brain, but no sequences hybridising to cytomegalovirus, varicella zoster virus, herpes simplex type I or JC or BK papovaviruses were detected in any of the experimental samples. These findings are discussed with reference to the viral hypothesis of the aetiology of psychiatric disease.

Adult↗
PubMed1987

The relative stability of positive and negative features in chronic schizophrenia.

The mental states of 92 inpatients with chronic schizophrenia were assessed on two occasions 4 years apart. The relationship between the two ratings was examined in the 84 patients who were either consistently on or consistently off neuroleptics. Negative features were more stable than positive, but were not irreversible. Every feature examined was shown to resolve in some cases.

Antipsychotic Agents↗
PubMed1987

Selective decreases in MAO-B activity in post-mortem brains from schizophrenic patients with type II syndrome.

The activities of the A and B forms of the enzyme monoamine oxidase (MAO, E.C. 1.4.3.4) have been assessed with the substrates 5-hydroxytryptamine and benzylamine respectively in seven areas of the brains of 39 patients with schizophrenia and 44 control subjects. Whereas previous studies have found the enzyme unchanged in brain in schizophrenia, in this study there was a modest but significant decrease in the activity of MAO-B in frontal and temporal cortices and in amygdala. This decrease could not be accounted for by neuroleptic medication, age, sex or post-mortem variables. In a series of 22 patients who had been assessed in life, the reduction in MAO-B activity was found to be associated specifically with the presence of negative symptoms (flattening of affect and paucity of speech). The findings are therefore consistent with other evidence for structural and neurochemical change in the temporal lobe that have been associated with the type II (defect state) syndrome of schizophrenia. The change in enzyme activity is unlikely to be related to a change in monoamine metabolism but may reflect a disturbance in glial function. The change in MAO-B activity in brain in this study is confined to particular areas of brain and a subgroup of patients; it is thought to be entirely unrelated to earlier reports of reductions of enzyme activity in platelets, which are probably attributable to prolonged neuroleptic medication.

Aged↗
PubMed1986

Serotonergic mechanisms in brains of suicide victims.

Serotonergic mechanisms have been investigated in postmortem brain samples from controls and suicide victims. The concentrations of 5-hydroxytryptamine (serotonin; 5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were determined in occipital cortex and hippocampus and the high-affinity binding of ligands to the 5-HT1, 5-HT2 and imipramine-binding sites was assessed in frontal cortex, occipital cortex and hippocampus. The only significant difference between the two groups was a modest increase in 5-HIAA levels in the hippocampus of suicide victims. There was no evidence to suggest that those suicide victims with a clinical history of depression represented a subgroup with altered metabolite levels or binding values. The storage conditions of the samples were not related to the metabolite levels or binding values. There was, however, a significant positive correlation between [3H]imipramine binding and age in some brain regions. The results do not provide any evidence of gross alterations in 5-HT mechanisms in suicide or depression.

Adult↗