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Biomedical subjects

L E DeLisi

Publications and source records attributed to L E DeLisi.

At least 91 records · Page 5Linked to original sources
PubMed1989

Physical mapping, linkage analysis of a putative schizophrenia locus on chromosome 5q.

Two recent studies have suggested that a schizophrenia susceptibility locus may lie on the proximal long arm of chromosome 5. Partial trisomy of a 20-30 centimorgan region of chromosome 5 (5q11.2-13.3) was found to cosegregate with schizophrenia in a Canadian family of Chinese descent. Moreover, DNA markers from proximal 5q (D5S39, D5S76) were found to be linked to schizophrenia and related disorders in seven British and Icelandic families. We now report an initial physical map of DNA markers relative to the partial trisomy chromosome 5, as well as preliminary evidence against linkage of this region to schizophrenia in four American families.

Chromosome Mapping↗
PubMed1989

Concordance by sex in sibling pairs with schizophrenia is paternally inherited. Evidence for a pseudoautosomal locus.

The hypothesis that the gene for schizophrenia is located in the pseudoautosomal region of the sex chromosomes predicts that same-sex concordance will occur in paternally rather than maternally derived pairs. In 120 families that included at least one sibling pair with schizophrenia, affected members were significantly more likely to be of the same sex when there was a history of illness on the paternal than on the maternal side, the difference remaining significant when parent of origin was assessed by three different methods. The finding is as predicted by the pseudoautosomal hypothesis: therefore a search for the gene should be focused on this small (three megabase) region of the genome. The ratio of same to mixed sex pairs in paternally-derived cases (approximately 3:1) suggests the gene is located in the centromeric one-third of the pseudoautosomal region.

Adult↗
PubMed1988

A controlled family study of chronic psychoses. Schizophrenia and schizoaffective disorder.

Two hundred thirty-seven relatives of 48 patients with chronic psychosis, diagnosed as either schizophrenia or schizoaffective disorder, along with 380 relatives of psychiatrically normal controls, were studied using systematic diagnostic interviews, information from relatives, and review of medical records where appropriate. A variety of nonbipolar psychotic disorders was found in the relatives of the patients. Comparing relatives of patients with schizophrenia with relatives of patients with schizoaffective disorder, there was no tendency for schizoaffective diagnosis or acute psychoses to aggregate separately from schizophrenia. Increased incidence of bipolar disorder was found in relatives of patients with schizoaffective disorder but not in relatives of patients with schizophrenia. Incidence of major affective disorder (bipolar and unipolar) was increased in relatives of probands with both types of psychoses. If we subdivide the ill probands according to whether or not they had a history of substance abuse, relatives of probands with substance abuse had greater frequency of affective disorder and substance abuse, but there were not significant differences in the number of relatives with nonbipolar psychoses.

Adolescent↗
PubMed1988

Perinatal complications and reduced size of brain limbic structures in familial schizophrenia.

Both genetic and nongenetic risk factors for schizophrenia have been described. Specifically, perinatal complications have been suggested as a factor in the later development of schizophrenia. These appear to be increased among schizophrenic patients with a clear genetic vulnerability for illness. While reduced brain tissue localized to the temporal lobe is also present in these individuals, it is unknown whether brain structural differences are a consequence of perinatal insults to the developing brain. Initial analyses on magnetic resonance imaging scans from siblings with schizophrenia are presented in an attempt to examine this issue.

Adult↗
PubMed1987

Dysfunction in a prefrontal substrate of sustained attention in schizophrenia.

Regional brain metabolism was measured in normal subjects and patients with schizophrenia while they performed an auditory discrimination task designed to emphasize sustained attention. A direct relationship was found in the normal subjects between metabolic rate in the middle prefrontal cortex and accuracy of performance. The metabolic rate in the middle prefrontal cortex of patients with schizophrenia, even those who performed as well as normals, was found to be significantly lower than normal and unrelated to performance. The findings point to a role of the mid-prefrontal region in sustained attention and to dysfunction of this region in schizophrenia.

Adult↗
PubMed1987

Clinical features of illness in siblings with schizophrenia or schizoaffective disorder.

Evidence implicating genetic or prenatal-perinatal environmental causes in the familial aggregation of schizophrenia led us to study 53 sets of siblings, two or more of whom had chronic psychosis, either schizophrenia or schizoaffective disorder. We looked for similarities in clinical features and concordance of diagnosis within sibships to test for shared familial causes. Clinical variables, including diagnosis, specific symptoms, age at onset, and nongenetic perinatal factors, were studied. Auditory hallucinations, paranoid delusions, thought disorder, negative symptoms, and poor premorbid social adjustment did not significantly correlate in siblings. Concordance was found for schizoaffective disorder and history of major depressive episodes, suggesting that schizophrenia with a depressive component and Research Diagnostic Criteria schizoaffective illness may represent a specific etiologic subtype(s) of the illness, whereas the other noted symptoms may represent the variable expression of the disorder. Age at onset and at first hospitalization were significantly correlated, consistent with genetic or other familial factors on time of onset. Birth complications were significantly more frequent among the schizophrenic compared with non-psychotic siblings, had a familial component, and tended to be associated with an earlier age at onset. Thus, nongenetic perinatal factors may increase the risk for schizophrenia in a familial form of the illness and contribute to the correlation of ages at onset in siblings.

Adult↗
PubMed1987

Positron emission tomography studies of basal ganglia and somatosensory cortex neuroleptic drug effects: differences between normal controls and schizophrenic patients.

Glucose metabolic rate in the basal ganglia, thalamus, and somatosensory cortex was examined in eight patients with schizophrenia before and after receiving neuroleptic medication. Basal ganglia metabolic rates were increased with medication: more on the right than on the left and more in putamen than caudate. The cortical anteroposterior ratio, an index of relative hypofrontality, was not affected by neuroleptics. The brain areas that were found to be altered by neuroleptics were selected for comparison between off-medication schizophrenics and controls. Metabolic rates in the basal ganglia tended to be low in patients with schizophrenia in comparison to 24 age- and sex-matched controls.

Adolescent↗
PubMed1987

Glucose utilization in the temporal cortex of affectively ill patients: positron emission tomography.

As temporal lobe dysfunction has been postulated in the affective disorders, the authors investigated glucose utilization in the temporal lobes of 13 affectively ill patients in comparison with 18 normal volunteer controls and 17 previously reported schizophrenic patients, following injections of fluorine 18-2-deoxy-D-glucose (FDG) during somatosensory stimulation to the right forearm. Using a boundary-finding algorithm to outline each temporal lobe, maximum glucose use relative to maximums elsewhere in the same positron emission tomography (PET) slice were calculated. In a small group of moderately to severely depressed patients, this relative measure was significantly reduced in the right (with a similar trend in the left) temporal lobe compared to normal volunteers and the other comparison groups. The lack of a significant increase in glucose utilization, measured either as a maximum or in relation to other areas in the PET scan slice, suggests that a temporal lobe activation or a seizure-like process is not generally occurring during active depressive phases of the illness.

Affective Disorders, Psychotic↗
PubMed1987

Studies of biological factors associated with the inheritance of schizophrenia: a selective review.

Although a familial component to schizophrenia has been established through several family, twin and adoption studies, an inherited biological factor has yet to be established. Efforts to define clinical familial subtypes of schizophrenia have generally been unsuccessful, although recent data from our study population of pairs of siblings with schizophrenia suggests that schizophrenia with recurrent episodes of major depression may define one such group. There have only been a few biological traits consistently found to be associated with schizophrenia and also found to be heritable. These findings (e.g. measures of monoamine metabolism, brain structural morphology, neurophysiological markers, and protein polymorphisms) are reviewed in the present chapter. The proportion of patients with any of the noted abnormalities never approaches 100%, nor have any been found to be specific to schizophrenia. Research into the biogenetics of schizophrenia is clearly just beginning.

Brain↗
PubMed1987

Neuropeptide gene polymorphisms in affective disorder and schizophrenia.

The restriction fragment length polymorphisms (RFLPs) associated with neuropeptide Y (NPY) and somatostatin loci were used to assess the possibility of linkage to a locus for affective disorder (AD). When somatostatin haplotypes were assigned to members of 2 AD pedigrees under either rare dominant or recessive transmission, the LOD scores obtained at 0% recombination were inconsistent with linkage. Similar results were obtained with NPY under rare dominant inheritance. Comparison of the frequency of the genotypes deduced from the polymorphic alleles of gastrin-releasing peptide, NPY, somatostatin and substance P in normals vs patients with either AD or schizophrenia suggests the absence of association. The difference in the frequency of the 3.3 kb adenosine deaminase fragment in normals vs bipolar and schizophrenic patients is of borderline significance.

Adult↗
PubMed1987

Relationship of HLA to schizophrenia in 10 nuclear families.

We tested the hypothesis of linkage of HLA (human leukocyte antigens) and schizophrenia in 10 nuclear families that were ascertained on the basis of at least two siblings affected with chronic schizophrenia (SCH), as defined by Research Diagnostic Criteria, with or without superimposed affective disorder. All available parents and siblings were interviewed and typed for HLA antigens at the A, B, C, and Dr loci. Lod scores for linkage between HLA and a putative SCH-locus were calculated using the program LIPED, assuming several possible models for the mode of transmission of the SCH locus. Linkage was also tested with DSM-III schizotypal and paranoid personality disorders considered as part of the illness phenotype. The lod score analysis indicated that for most models of inheritance of schizophrenia, close linkage to HLA could be excluded. The results did not change if individuals with "spectrum" disorders were considered affected. We also tested for linkage using the affected sib-pair method which does not require any assumptions about the mode of transmission of the illness. The results of this analysis also indicated that linkage to HLA was very unlikely. If our results are considered together with other published studies, a susceptibility locus for schizophrenia or "schizophrenia spectrum" is not likely to be in the HLA region of chromosome 6.

Chromosome Mapping↗
PubMed1986

A family study of the association of increased ventricular size with schizophrenia.

Families with more than one individual of the same generation with the diagnosis of schizophrenia were recruited for studies. Brain lateral ventricular size was quantified in 26 schizophrenic subjects from 12 unrelated families, their available well siblings (N = 10), and 20 nonpsychotic controls. Lateral ventricular size was significantly greater in the schizophrenics than in their well siblings and controls. In addition, an analysis of variance of the data showed a significant familial component to ventricular size. Although histories of head injury and birth complications were also associated with ventricular size, these were not sufficient to explain both the familial aspect of ventricular size and the association of greater ventricular size with schizophrenia within these families.

Adult↗
PubMed1986

Serotonin and 5-hydroxyindoleacetic acid in brains of suicide victims. Comparison in chronic schizophrenic patients with suicide as cause of death.

Serotonin (5-HT) and 5-hydroxyindoleacetic acid concentrations were determined in various brain areas of nonschizophrenic suicide victims, chronic schizophrenic patients with or without suicide as the cause of death, and normal control subjects without psychiatric or neurologic disorders. Serotonin concentrations in the basal ganglia were significantly elevated in suicide victims and chronic schizophrenic patients, as were 5-hydroxyindoleacetic acid concentrations in the occipital cortex. These differences were not specific to either patient group and may have been caused by neuroleptic or antidepressant treatment. A decreased 5-HT concentration was found in the hypothalamus of nonschizophrenic suicide victims. Among the chronic schizophrenic patients, there was no significant difference in the hypothalamic 5-HT content between the suicide victims and others, indicating that low 5-HT levels in the hypothalamus are not characteristic of schizophrenic patients who died of suicide.

Adolescent↗
PubMed1986

The third biannual winter workshop on schizophrenia. Schladming, Austria, Jan 26-31, 1986.

The following general principles seem to summarize the emphasis that was evident from the several days of multiple presentations and discussions. The need exists to continue to develop improvements in the tools applicable to research in psychiatry, both clinical and biological "instruments" that are both sensitive and specific to the questions asked. New molecular genetic technology has already been used to explore genetic susceptibility hypotheses, as well as novel viral associations. Imaging of brain receptor kinetics in vivo is in progress. Improvements in structured clinical rating scales for quantifying changes in biologically important clusters of symptoms (eg, negative vs positive symptoms) or the defining of prodromal symptoms that lead to relapse are critical to progress in etiological and treatment research. A genetic factor or factors for schizophrenia exist, although whether a "familial" type defines only a subgroup of schizophrenia is controversial. The relative importance of genetic vs environmental variables, and whether there is genetic and environmental heterogeneity, continue to be debated. The most important epidemiological data, the seasonality of birth, and the controversial question of geographical variation in prevalence can be clues to the etiology of schizophrenia and are presently being clarified. The pursuit of new treatments and modifications of present conventional treatments to increase the percentage of patients recovering from psychotic illnesses or lead to more complete recovery states is always of prime importance. An emphasis on clarifying the dopamine hypothesis of schizophrenia with PET continues to be at the forefront of psychiatric research. A focus on patients in a first episode of schizophrenia can clarify major issues.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗