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Biomedical subjects

B Kirkpatrick

Publications and source records attributed to B Kirkpatrick.

At least 55 records · Page 3Linked to original sources
PubMed1997

Attentional impairments in deficit and nondeficit forms of schizophrenia.

OBJECTIVE: Previous studies of attention/information processing impairments in schizophrenia suggest that patients with the deficit syndrome should be characterized by impaired performance on measures of visual information processing. Therefore, the authors examined whether two measures of visual information processing, a degraded stimulus version of the continuous performance test and a forced choice span of apprehension task, were uniquely related to the deficit syndrome. METHOD: Performance on the continuous performance test and span of apprehension task was examined in 20 deficit and 56 nondeficit patients with schizophrenia and in 27 subjects in a normal comparison group. RESULTS: Deficit patients performed significantly less well than both nondeficit patients and the normal comparison group on the continuous performance test and span of apprehension task. There were no significant differences between the nondeficit patients and the normal group on the continuous performance test, but nondeficit patients performed significantly less well on the span of apprehension task than the normal group. Differences between the deficit and nondeficit patients in performance on the continuous performance test and span of apprehension task were not related to total scores on the Brief Psychiatric Rating Scale factor 1 or on the Thought, Language, and Communication scale or to neuroleptic level. CONCLUSIONS: The results suggest that deficit patients are uniquely characterized by impaired performance on the continuous performance test. The deficit patients' differential performance on the continuous performance test may be related to either an inability to activate and allocate attention or an impairment in the perceptual organization of visual information.

Adult↗
PubMed1997

Visual information-processing impairments in deficit and nondeficit schizophrenia.

OBJECTIVE: Previous studies of covert visuospatial attention in schizophrenia suggest a subtle form of right hemispatial neglect in acutely ill patients but not in chronic, stable patients. Because of previous work documenting various visual information-processing abnormalities in deficit schizophrenia, the authors investigated whether the deficit/nondeficit categorization would help clarify the presence of visual attentional asymmetries in schizophrenia. METHOD: Performance on a covert visuospatial attention task was examined in clinically stable outpatients with schizophrenia (17 in a deficit subgroup and 28 in a nondeficit subgroup) and 25 normal subjects. Peripheral cue and central cue versions of the covert visuospatial attention task, at 100-, 200-, and 800-msec intervals between cue and target, were administered a week apart. RESULTS: The nondeficit patients exhibited a significant and abnormal asymmetry, with slower reaction time to targets presented in the right visual field than in the left visual field. This right visual field disadvantage was found with both versions of the task, but only at the 100-msec cue-target interval. The deficit patients were slowest in overall reaction time but, similar to the normal subjects, showed no asymmetry. CONCLUSIONS: The results are consistent with slower visual information processing in the left compared to the right cerebral hemisphere in nondeficit schizophrenia. This finding cannot be accounted for by differences between the deficit and nondeficit subgroups in demographic characteristics, chronicity, or medication effects, nor is it secondary to generalized cognitive impairment.

Adolescent↗
PubMed1996

The deficit syndrome in the Suffolk County Mental Health Project.

Patients with schizophrenia in the Suffolk County Mental Health Project were categorized into groups with (n = 32) and without (n = 52) the deficit syndrome, using a case identification method based on the Brief Psychiatric Rating Scale. The deficit group had a lower level of function at both index admission and 24-month follow-up; these differences could not be attributed to group differences in demographic variables, chronicity of illness, or a greater severity of psychosis in the deficit syndrome group. The number of patients categorized as deficit was greater at 24 months (34%) than at 6 months (25%).

Adult↗
PubMed1996

Social isolation in animal models of relevance to neuropsychiatric disorders.

Animal models of social isolation have been suggested to be relevant to several neuropsychiatric disorders; however, social isolation is usually not purely an alteration of social environment, as it often involves such factors as decreased complexity of the environment, loss of tactile stimulation, and increased metabolic demands of temperature maintenance. In this study, female prairie voles (Microtus ochrogaster, a highly social rodent) were assigned to four experimental groups: continued housing with sibs, with or without nesting material; and individual housing, with or without nesting material. Isolation increased serum corticosterone but did not alter weight. There was no statistical interaction between these two factors. In animal models, factors other than specifically social variables may contribute to the physiological response to social isolation, and the various aspects of the stress response may respond differentially to these factors.

Animals↗
PubMed1996

The deficit syndrome in the DSM-IV Field Trial. Part II. Depressive episodes and persecutory beliefs.

Patients with the deficit syndrome are remarkable for their decrease in interest in social relationships, suggesting they have an abnormality in those brain regions controlling social behavior and social cognition. To further assess social behavior and social cognition in this group of patients, we examined the relationships among three aspects of the psychopathology: suspiciousness; major depressive episodes; and the deficit syndrome. These features of psychopathology were examined in two clinical samples: stable outpatients from a research clinic (the MPRC sample), and patients in the DSM-IV Field Trial. In both samples, patients with history of a depressive episode had more severe suspiciousness than those without such a history; other psychotic symptoms were not associated with depressive episodes. In the MPRC sample, patients with the deficit syndrome exhibited less severe suspiciousness than nondeficit patients; in the Field Trial sample, this same comparison had a nonsignificant trend in the same direction. In the Field Trial sample, patients with the deficit syndrome also had less severe delusions with a predominantly social content than did nondeficit patients. These findings suggest suspiciousness is a risk factor for major depression in schizophrenia, and that the decreased interests in social relationships exhibited by deficit syndrome patients is reflected in the content of their delusions.

Adult↗
PubMed1996

The deficit syndrome in the DSM-IV Field Trial: I. Alcohol and other drug abuse.

Drug abuse is common in schizophrenia. Previous studies suggested patients with the deficit syndrome have a lower risk of drug abuse than do patients without deficit features. We distinguished deficit and nondeficit groups in the DSM-IV Field Trial dataset, and compared the two groups relative to current and lifetime (worst ever) severity of alcohol, cannabis, and other drugs of abuse. Deficit syndrome patients had a lower severity of current use of alcohol and other drugs, but the two groups did not differ significantly relative to cannabis use. Deficit patients also had less severe lifetime use of all three classes of drugs. These findings could not be attributed to differences between the deficit and nondeficit groups in demographics, severity of psychotic symptoms, chronicity of illness, or the quality of information available for the two groups. Deficit categorization and drug abuse were independently associated with poor level of function. Negative symptoms broadly defined were weaker predictors of drug abuse than was the deficit/nondeficit categorization. These findings further support the validity of the deficit syndrome of schizophrenia. Within schizophrenia, groups with relatively high or low risk for substance abuse can be identified.

Adult↗
PubMed1996

Fluoxetine augmentation of clozapine treatment in patients with schizophrenia.

OBJECTIVE: The authors examined the efficacy of fluoxetine augmentation of clozapine treatment response in schizophrenic outpatients who, despite adequate treatment with clozapine, continued to exhibit persistent positive or negative symptoms. METHOD: Thirty-three patients completed on 8-week, double-blind, parallel-groups comparison of adjunctive fluoxetine and placebo. RESULTS: There were no significant differences in positive, negative, depressive, or obsessive-compulsive symptoms between patients given adjunctive fluoxetine or placebo. CONCLUSIONS: These results suggest that fluoxetine is not effective in augmenting clozapine treatment response.

Adult↗
PubMed1995

New diagnostic issues in schizophrenic disorders.

The evolution of our understanding of schizophrenia has provided new concepts that substantially alter answers to questions such as age of onset, distribution by sex, and treatment response. Moreover, these new concepts offer heuristic advantages in etiopathophysiological study designs and permit investigators to address key sources of artifact. We discuss the unitary versus the clinical syndromal concept of schizophrenia and describe the implications of the latter with regard to the study of schizophrenia. We also present a heuristic tripartite division of schizophrenic symptoms for reducing syndromal heterogeneity.

Age of Onset↗
PubMed1994

Limbic system fos expression associated with paternal behavior.

Axon-sparing lesions of the medial nucleus of the amygdala (MeA) decrease male parental behavior in the highly social prairie vole. To assess further the role of the amygdala in paternal behavior, male and female prairie voles were exposed to a pup or a non-social olfactory stimulus for 3 hours, and cells expressing Fos peptide were labelled using immunocytochemistry. Compared to controls, males exposed to a pup showed an increase in Fos expression in the MeA, as well as in several areas with connections to it: the accessory olfactory bulb, lateral septum, medial preoptic area, medial bed nucleus of the stria terminalis, nucleus reuniens and paraventricular nucleus of the thalamus. There was no increase in Fos immunoreactivity in the paraventricular nucleus of the hypothalamus or piriform cortex. The same pattern of Fos expression was found in female voles, with the exception of the thalamic paraventricular nucleus, where there was an increase in the pup-exposed group that was not statistically significant (P = 0.11). In addition, the magnitude of induction in females was markedly less than that in males in the medial preoptic area. These results provide further evidence that the MeA is involved in paternal behavior, and suggest certain other areas previously implicated in meternal behavior may also be involved in the control of paternal behavior in this species.

Animals↗
PubMed1994

Neuropsychological impairments in deficit vs nondeficit forms of schizophrenia.

BACKGROUND: Previous studies have suggested that functional impairments of the frontal and parietal lobes are related to the deficit symptoms of schizophrenia. The purpose of the current study was to examine whether neuropsychological measures of frontal and parietal lobe function differentiated deficit from nondeficit patients. Neuropsychological measures of temporal lobe function were used as contrast measures. METHODS: The performance of 18 deficit and 21 nondeficit schizophrenic patients was examined on neuropsychological measures of executive, visuospatial, and memory functions, selected on the basis of their association with lesions of either the frontal, parietal, or temporal lobes. The results from the schizophrenic subgroups were compared with the results on the same measures obtained from 30 normal controls. RESULTS: Deficit patients performed more poorly than nondeficit patients on two frontal lobe measures, the Stroop Color-Word Interference and Trails Making B tests, and one parietal lobe measure, the Mooney Faces Closure Test. There were no differences in performance on the temporal lobe measures between the two groups. Both groups performed more poorly on the tests than the normal controls. CONCLUSIONS: The results suggest that deficit patients may have greater performance impairments on neuropsychological measures associated with frontal and parietal neuropsychological abnormalities.

Adult↗
PubMed1994

Characterization of high-frequency deletions in the iaa-containing plasmid, pIAA2, of Pseudomonas syringae pv. savastanoi.

The phytopathogenic bacterium Pseudomonas syringae pv. savastanoi causes olive and oleander knot disease. The bacterium induces the formation of tumorous galls by the synthesis and secretion of the plant hormones trans-zeatin riboside and indole-3-acetic acid into host intercellular spaces. An Italian oleander isolate, PB213, has been observed to lose the ability to synthesize IAA at high frequency, thus becoming non-pathogenic. The IAA genes, located on the 72-kb iaa-containing plasmid, pIAA2 were lost mainly due to two classes of deletions: 18 or 22 kb in length. Both classes of deletions had a common endpoint upstream of the IAA genes. The other endpoints were in areas that flanked the insertion sequence element IS51. The endpoints are in regions of repetitive DNA of at least 271 bp that have been designated a/b.

Base Sequence↗