Biomedical subjects

R M Murray

Publications and source records attributed to R M Murray.

At least 109 records · Page 6Linked to original sources

PubMed1999

Failure to respond to treatment with typical antipsychotics is not associated with CYP2D6 ultrarapid hydroxylation.

AIMS: To investigate whether or not there is a correlation between failure to respond to typical antipsychotics and CYP2D6 ultrarapid metaboliser status. METHODS: CYP2D6 phenotype (metaboliser status) was assigned following genotyping for gene duplication, as well as for the CYP2D6*3, CYP2D6*4, and CYP2D6*5 null alleles in 235 treatment-refractory patients and 73 nonrefractory patients. RESULTS: Four (1.7%) of the 235 treatment-refractory subjects were positive on the duplication assay, but, of these, two were found to represent duplications of a null allele (CYP2D6*4 ), therefore leaving only two (0.85%) positive for duplication of a wild type allele (ultrarapid metabolisers). Three (4.1%) of the nonrefractory subjects had a genotype consistent with ultrarapid metaboliser status. Fisher's exact test gave a two-tailed P value of 0.091, i.e. a trend towards an excess of ultrarapid metabolisers in the nonrefractory group, which was in the opposite direction to that predicted by our hypothesis. CONCLUSIONS: Although the results show a trend towards an excess of ultrarapid metabolisers in the nonrefractory group, the percentages in the two groups of patients are both within the range for ultrarapid metabolisers in Caucasian populations. Our data are not consistent with ultrarapid metaboliser status being a major cause of failure to respond to typical antipsychotics.

Alleles↗

PubMed1999

Supra-regional brain systems and the neuropathology of schizophrenia.

At what levels of brain organization might pathological change in schizophrenia be anatomically expressed: global, regional or supraregional? We hypothesised that brain structure reflects a set of supra-regional anatomical systems with common developmental influences. We conducted an exploratory analysis to identify supraregional brain systems and to investigate whether abnormal brain architecture in schizophrenia is manifested within one or more of these systems. Magnetic resonance (MR) images were acquired from 27 patients with schizophrenia and 37 control subjects. After segmentation and registration of each individual MRI dataset in the standard space of Talairach and Tournoux, grey matter and ventricular-cerebrospinal fluid (CSF) maps were automatically parcellated into 104 regions. We used principal components analysis of the multiple regional grey matter and ventricular-CSF measurements, on all 64 subjects, to extract the five main normative supra-regional systems. The first two of these components represented global variation in grey matter and ventricular-CSF regional measures. We interpreted the other three components as representing supra-regional systems comprising: a frontal-parietal system, a frontal-temporal system and a frontal-basal ganglia system. Schizophrenic group mean scores on the first component (global grey matter-ventricular contrast) and fourth component (frontal-temporal system) were significantly reduced compared to controls. These results suggest that pathological change in schizophrenia may be expressed at two mutually independent levels of anatomical organization: global change in a grey matter/ventricular system and supra-regional change in a frontal-temporal system.

Adult↗

PubMed1999

Schizophrenia and complications of pregnancy and labor: an individual patient data meta-analysis.

Several epidemiological studies have reported an association between complications of pregnancy and delivery and schizophrenia, but none have had sufficient power to examine specific complications that, individually, are of low prevalence. We, therefore, performed an individual patient meta-analysis using the raw data from case control studies that used the Lewis-Murray scale. Data were obtained from 12 studies on 700 schizophrenia subjects and 835 controls. There were significant associations between schizophrenia and premature rupture of membranes, gestational age shorter than 37 weeks, and use of resuscitation or incubator. There were associations of borderline significance between schizophrenia and birthweight lower than 2,500 g and forceps delivery. There was no significant interaction between these complications and sex. We conclude that some abnormalities of pregnancy and delivery may be associated with development of schizophrenia. The pathophysiology may involve hypoxia and so future studies should focus on the accurate measurement of this exposure.

Case-Control Studies↗

PubMed1999

No evidence of linkage disequilibrium between a CAG repeat in the SCA1 gene and schizophrenia in Caucasian and Chinese schizophrenic subjects.

Several recent studies have reported evidence for a schizophrenia locus on chromosome 6p, with a variety of linked markers spanning a approximately 40 cM region between D6S470 and D6S291. However because of the wide region implicated and the difficulty of inferring phenotype from genotype in complex disorders, it is difficult to define its location precisely using linkage data. An alternative approach is to search for linkage disequilibrium. On chromosome 6p, allelic association with a (CAG)29 allele of a triplet repeat marker in the SCA1 gene has been reported, and we have attempted to replicate this finding using a Caucasian case-control sample of 211 affected subjects and 204 controls, and a Han Chinese sample of 100 affected family trios. In the case-control sample, the frequency of the (CAG)29 allele was similar in cases and controls (35%), and no other alleles provided evidence for allelic association. Likewise, there was no evidence for preferential transmission of the (CAG)29 allele to affected offspring in the Chinese sample, although a different allele, (CAG)26, was more often transmitted to the affected offspring. However this data did not reach statistical significance (P = 0.1). We conclude that our data does not support the notion that there is a locus for schizophrenia close to the SCA1 gene. However, since linkage disequilibrium will vary between distinct populations, we cannot exclude this possibility.

Asian People↗

PubMed1999

Prevalence and predictors of parasuicide in chronic psychosis. UK700 group.

OBJECTIVE: This study estimates the prevalence of and risk factors for parasuicide in a large community-based sample of patients with chronic psychosis. METHOD: A total of 704 subjects with chronic psychosis were interviewed using a battery of instruments. The 2-year prevalence of parasuicide was estimated and a comparison was made between attempters and nonattempters on a wide range of sociodemographic and clinical variables. RESULTS: The 2-year prevalence of parasuicide was 18.8%. Attempters were significantly more likely to be younger, of white ethnic origin, to have a diagnosis of affective disorder, to be currently depressed, to have experienced more auditory hallucinations and to have received treatment with antipsychotic drugs for a longer period. CONCLUSION: Parasuicide was found to present a considerable clinical problem in this group. Continual risk assessment is essential to reduce this unacceptably high rate.

Adolescent↗

PubMed1999

Infection of mice lacking interleukin-7 (IL-7) reveals an unexpected role for IL-7 in the development of the parasite Schistosoma mansoni.

A single intradermal administration of recombinant interleukin-7 (IL-7) has been shown to aggravate the course of murine schistosomiasis, to favor the development of Th2-associated antibodies specific for the parasite, and to alter migration kinetics and/or migratory route of the parasite within its vertebrate host. Here we show that after infection of IL-7-deficient mice with Schistosoma mansoni, the predominant parasite-specific humoral response follows a Th1 pattern, and the development of the parasite is greatly impaired. In IL-7-deficient mice, increased numbers of larvae reach the lungs and fewer larvae reach the liver, compared to control mice. In the absence of IL-7, female worms show an altered fecundity, leading to decreased numbers of eggs trapped in the tissues and to an amelioration of the pathology of the infected host. The most striking observation is the blockade of parasite growth in an IL-7-defective environment, leading to dwarf male and female worms. The results of this study have important implications for the role of IL-7 in the host-parasite relationship and show how parasites can disable or evade the host immune response.

Animals↗

PubMed1998

Analysis of CAG/CTG repeat size in Chinese subjects with schizophrenia and bipolar affective disorder using the repeat expansion detection method.

BACKGROUND: Family studies of schizophrenia and bipolar affective disorder provide evidence for genetic anticipation, which (in common with a number of mendelian disorders), may be caused by triplet repeat expansion. This hypothesis is strengthened by evidence from repeat expansion detection (RED) analysis revealing association between the psychoses and long CAG/CTG trinucleotide repeats. METHODS: We performed RED on Han Chinese subjects with schizophrenia (82), bipolar affective disorder (43), and normal controls (61), using a CTG10 oligonucleotide. RESULTS: Comparison between cases and controls revealed no significant association between long repeats and affected status. We also found no detectable association with age at onset and repeat length in either bipolar affective disorder or schizophrenia. Overall, the size distribution of CAG/CTG repeats in Chinese subjects was not significantly different from those reported previously for Caucasian subjects. CONCLUSIONS: These findings indicate that CAG/CTG repeat expansion is not likely to be a major etiological factor for psychosis in Chinese populations.

Adolescent↗

PubMed1998

Transmission disequilibrium analysis of a triplet repeat within the hKCa3 gene using family trios with schizophrenia.

hKCa3 is a neuronal small conductance calcium-activated potassium channel which contains a polyglutamine tract, encoded by a polymorphic CAG repeat in the gene. Since an association between longer alleles of the CAG repeat and schizophrenia has been reported, we performed haplotype-based haplotype relative risk (HHRR) and transmission disequilibrium (TDT) in 97 family trios with schizophrenia from SW China. We found no evidence for an excess of longer CAG repeats in the patients, and the ETDT test was not significant for either allele-wise (P = 0.31) or genotype-wise analysis (P = 0.18). However, there was a deficit of transmission of the (CAG)20 repeat allele to affected offspring when this allele was considered individually by TDT (P = 0.012; not corrected for multiple testing). These data do not support a role for larger alleles at the hKCa3 locus in psychosis in Chinese subjects.

Adolescent↗

PubMed1998

Assessment of serotonergic function in major depression using d-fenfluramine: relation to clinical variables and antidepressant response.

BACKGROUND: d-Fenfluramine, a specific serotonin (5-HT)-releasing agent without the catecholamine effects of d,l-fenfluramine, was used as a serotonergic neuroendocrine challenge in subjects with unipolar major depression. METHODS: Patients were given 30 mg of d-fenfluramine orally, and prolactin and cortisol responses were measured over the following 5 hours. Endocrine responses were examined in relation to clinical variables and subsequent response to antidepressant treatment. RESULTS: 5-HT-mediated cortisol responses at baseline were inversely correlated with depression severity on the Montgomery Asberg Depression Rating Scale, Bech Melancholia Scale, and Clinical Global Impression scale. Prolactin responses were inversely correlated with anxiety on the Brief Symptom Inventory. A higher initial cortisol response to d-fenfluramine predicted a subsequent good antidepressant response. CONCLUSIONS: We conclude that: a) the severity and symptom profile in major depression may be closely related to 5-HT dysfunction; and b) higher cortisol responses to d-fenfluramine predict a preferential response to treatment.

Adult↗

PubMed1998

Auditory hallucinations: a review of psychological treatments.

Auditory hallucinations (AH) occur frequently amongst psychiatric patients, being most common in schizophrenia. In 25-30% of cases they are refractory to traditional antipsychotic drugs. A variety of psychosocial treatments have been used, but their efficacy remains unclear. This review aims to bring together the more recent studies of psychological treatments and discuss them in the context of recent cognitive models of hallucinations and functional imaging studies. The search strategy included the following sources: MEDLINE, Embase and Psychlit. Strategies reported by patients can be categorised as: (1) distracting activities, such as listening to music; (2) behavioural tasks, such as taking exercise; (3) cognitive tasks, such as ignoring AH. Almost all the strategies produced some benefit in some patients: treatment often improved AH-associated distress, rather than frequency of AH. There are many difficulties in conducting research on AH. Treatment should be individually tailored and used as an adjunct to pharmacotherapy. Future theory-driven studies need to be based on complex aetiological models and incorporate functional imaging to elucidate the physiological changes induced by therapeutic interventions.

Antipsychotic Agents↗

PubMed1998

Meta-analysis of studies on genetic variation in 5-HT2A receptors and clozapine response.

Serotonin (5-HT) neurotransmitter receptors are targeted by atypical antipsychotic drugs. We hypothesized that genetic variation in these receptors may affect clinical response to the drugs targeting them. This hypothesis has been tested by several studies in which the correlation between polymorphic variants in the 5-HT2A receptor gene and clinical response to the atypical antipsychotic clozapine was investigated. The results of these studies either found association between 5-HT2A genetic variants and clozapine response or found differences in the same direction which did not reach statistical significance. Meta-analysis of these studies including 373 patients who responded to the treatment and 360 non-responders showed association between two 5-HT2A polymorphisms, 102-T/C and His452Tyr, and clozapine response. Statistical analysis of extreme responders showed a clearer association of the 102-T/C with clozapine response. These results reinforce the hypothesis and strengthen the candidacy of these receptors as important therapeutic targets.

Alleles↗

PubMed1998

A transmission/disequilibrium study of the DRB1*04 gene locus on chromosome 6p21.3 with schizophrenia.

Patients with schizophrenia rarely develop rheumatoid arthritis, an autoimmune disease that exhibits genetic association with the HLA DRB1*04 gene. We previously investigated the hypothesis that schizophrenia is negatively associated with DRB1*04, and found that only half the expected number of schizophrenic patients had this gene when compared with controls. We now report the results of DRB1*04 genotyping in pedigrees multiply affected with schizophrenia. Polymerase chain reaction amplification and sequence-specific oligonucleotide probes were used to determine the DRB1 genotypes of the 187 members of 23 pedigrees multiply affected with RDC schizophrenia. DQA1, DQB1 and DPB1 genotypes were similarly determined. We analysed data using the extended transmission/disequilibrium test and found a trend for the preferential non-transmission of DRB1*04 alleles from heterozygous parents to their schizophrenic offspring (16 of 23 alleles not transmitted, chi 2 = 3.5, p = 0.06). We found no evidence for a gene of major effect using GENEHUNTER for parametric and non-parametric linkage analysis. The results from this small sample need to be interpreted with caution, but they are in keeping with previous reports and suggest that HLA DRB1*04 alleles may be associated with a reduced risk of schizophrenia.

Alleles↗

PubMed1998

Serotonin transporter gene and risk for bipolar affective disorder: an association study in Spanish population.

BACKGROUND: The serotonin transporter (5-HTT) is an important candidate gene for the genetic transmission of manic depressive illness. Many studies of patients with affective disorders have found abnormalities in serotonin metabolism and dysregulation of the transporter itself. In the present study, we hypothesize that genetic variation in the 5-HTT gene (17q11.1-17q12) may have an effect in the etiology of manic depression. METHODS: To test this hypothesis, we analyzed allele, genotype, and haplotype frequencies of two polymorphisms recently described in the 5-HTT gene (a variable number of tandem repeats in intron 2 and a deletion/insertion polymorphism in the transcriptional control region) in a sample of 88 patients with manic-depressive illness and 113 controls. Cases and controls were matched for ethnic and geographic origin. RESULTS: No associations were found between any of these polymorphisms, tested individually or as haplotypes, and manic depression. Moreover, the genetic analysis by sex, presence/absence of psychiatric family history, and age of onset did not reveal significant differences in allele or genotype distributions. CONCLUSIONS: Our results suggest that the genetic variability of the 5-HTT gene is not a major risk factor for manic depression.

Adolescent↗

PubMed1998

Does dysplasia cause anatomical dysconnectivity in schizophrenia?

Evidence is reviewed that dysplastic brain development in the second half of pregnancy predisposes to schizophrenia. We suggest that an important corollary of aberrant development at this stage of ontogenesis is abnormal afferentation of the cortical plate, and that this may be macroscopically measurable in terms of abnormal correlational structure in adult brain imaging data. This prediction is tested by analysis of multiple cortical volume measures on magnetic resonance imaging data acquired from 35 male right-handed schizophrenics and 35 matched controls. There are no significant differences between groups in global, intra-hemispheric or inter-hemispheric correlational structure; but schizophrenics are shown to have significantly reduced dependencies between frontal and temporal lobe volumes, and frontal and hippocampal volumes, in the left hemisphere. We conclude that anatomical dysconnectivity (between frontal and temporal cortex) in schizophrenia may be caused by dysplasia.

Adult↗

PubMed1998

Risk factors for onset and persistence of psychosis.

Clinical practice, training and evaluation of treatment in the functional psychoses continues to be carried out mostly along the traditional line of separation by diagnostic entity. However, the combined evidence from research on risk factors for onset and for persistence of psychotic illness indicates quantitative, but not qualitative, differences between categories of schizophrenia and affective psychosis. "Developmental" factors, such as childhood dysfunction, increased cerebral ventricle size and familial morbid risk of schizophrenia operate preferentially, though not specifically, at that end of the psychopathological spectrum characterised by a preponderance of negative features. On the other hand, "social" factors, such as ethnic group, adverse life events and familial morbid risk of affective disorder have a larger impact at the end associated with predominance of affective features. Heterogeneity in the functional psychoses may thus be best conceived as two discrete effects operating at different ends of a continuous psychopathological spectrum. The use of highly reliable but arbitrary diagnostic categories may introduce serious bias in aetiological and treatment research. Evidence supporting the validity of a model of shared risk factors for continuous characteristics needs to be further elaborated and incorporated into our concepts of psychotic illness.

Affective Disorders, Psychotic↗

PubMed1998

Abnormal 5-HT1D receptor function in major depression: a neuropharmacological challenge study using sumatriptan.

BACKGROUND: Sumatriptan, a specific agonist at 5-HT1D receptors, stimulates release of growth hormone (GH) and inhibits release of prolactin (PRL). METHODS: We gave sumatriptan (6 mg subcutaneously) to 11 patients with unipolar major depression and 11 control subjects matched for age, sex, weight and menstrual cycle phase. Serum GH and PRL were measured at 0, 15, 30, 45, 60 and 90 min after injection. RESULTS: The maximal rise in GH was significantly reduced in the depressed patients, with 60% showing no increase over baseline compared with 18% of controls. There were no significant differences in PRL responses. CONCLUSIONS: These results suggest reduced sensitivity of 5-HT1D receptors in major depression. Our results and those of studies investigating 5-HT1A receptors imply that both 5-HT1A and 5-HT1D autoreceptors may show reduced function in major depression.

Adult↗

PubMed1998

The dexamethasone suppression test in schizophrenia.

BACKGROUND: Cortisol non-suppression following the dexamethasone suppression test (DST) has been found to a variable extent in schizophrenia. The aetiology is unclear but may be related to depression or negative symptoms. METHODS: The DST was administered to 64 patients with DSM-IV schizophrenia. All patients were screened for DSM-IV major depression and rated on the Hamilton Rating Scale for Depression (HRSD), Scale for Assessment of Negative Symptoms (SANS) and the Brief Psychiatric Rating Scale (BPRS). RESULTS: DSM-IV criteria for major depression was fulfilled by 36% of the patients and 42% of patients had a history of parasuicide. Four patients had undetectable levels of dexamethasone and were excluded from the endocrine analyses. Only one remaining patient had a cortisol level above the cut-off point (> 138 nmol/l), indicating escape from dexamethasone suppression. The post-dexamethasone cortisol level correlated significantly with HRSD and BPRS scores but not with the SANS. The SANS and HRSD scores were not correlated, but they were independently correlated with the BPRS score. CONCLUSIONS: In contrast to some other work, rates of dexamethasone non-suppression were very low; together with the high rates of depression, this suggests that depression in schizophrenia may have a different neuroendocrine profile from major depressive disorders. Failure to measure dexamethasone levels can be misleading.

Adult↗

PubMed1998

Low activity allele of catechol-O-methyltransferase gene associated with rapid cycling bipolar disorder.

Catechol-O-methyltransferase (COMT) plays a major role in the breakdown of catecholamines. An amino acid polymorphism (val-108-met) determines high and low activity of the enzyme. A recent study in a small sample of patients with velo-cardio-facial syndrome who had bipolar affective disorder suggested that the Met (low activity) COMT allele might be associated with rapid-cycling in this population. We therefore tested the hypothesis that the Met allele might be associated with rapid cycling bipolar disorder in the wider population. We studied a sample of British Caucasian DSM-IV bipolar patients, of whom 55 met criteria for rapid cycling at some time during the illness and 110 met stringent criteria for a definite non-rapid cycling course. The COMT genotype was determined using a PCR assay. The low activity allele was more frequent in the group of rapid cyclers: 0.55 vs 0.42 (one-tailed chi 2 = 5.12, d.f. = 1, P = 0.012), and bearers of low activity alleles showed a dose-dependent increased risk of lifetime occurrence of rapid cycling: chi 2 test of linear association = 4.84, d.f. = 1, P = 0.014. Our data support the hypothesis that variation in the COMT gene modifies the course of bipolar disorder.

Alleles↗