Biomedical subjects

A Kasparek

Publications and source records attributed to A Kasparek.

7 recordsLinked to original sources

PubMed2000

Cognitive modulation of midbrain function: task-induced reduction of the pupillary light reflex.

The activation of processing resources has widespread effects in the nervous system. A model of pupillary control systems (Steinhauer S.R. , Hakerem G., 1992. The pupillary response in cognitive psychophysiology and schizophrenia. Ann. N.Y. Acad. Sci. 658, 182-204) had predicted that ongoing cognitive activation should result in inhibition of the light reaction at the level of the oculomotor nucleus, n. III, in the midbrain. In this study, modification of parameters of the pupillary reaction to light were examined during varying task demands. The averaged light reaction was recorded from 33 male and female healthy volunteers during the performance of a serial 7 subtraction task and compared to a 'no task' condition. For 13 subjects, an additional verbalization task with little processing demand (add 1) also was presented. Two types of effects were observed. Firstly, the tonic pupil diameter increased from the no task to the easy (add 1) task, and increased further in the more demanding condition (subtract 7). Secondly, the extent of the phasic light reaction was significantly reduced and the latency at the end of the contraction was significantly decreased in the 'subtract 7' condition compared to both the no task and easy conditions (which did not differ from each other). The locus of interference with the light reaction was the Edinger-Westphal complex of the oculomotor nucleus, which is the motor center for the pupillary sphincter muscles. Descending cortical influences inhibited the activity of the Edinger-Westphal complex. Thus, increasing activation had a tonic inhibitory effect on this center, while higher levels of processing complexity produced a separate component of inhibition that interacted with dynamic activation at this midbrain site. It was suggested that the variation in the light reaction is quantitatively responsive to varying processing loads, and may be utilized as a sensitive metric for a wide variety of cognitive operations.

Adolescent↗

PubMed1999

Modulation of language processing in schizophrenia: effects of context and haloperidol on the event-related potential.

BACKGROUND: Disturbances in language associations were among the first clinical symptoms reported for individuals described as schizophrenic (Bleuler 1911/1950). Currently, associative language disturbance is a diagnostic feature of schizophrenia (American Psychiatric Association 1994); however, the mechanisms that produce this symptom remain unknown. In the present study, two candidate psychological functions were examined: sensitivity to semantic context and expectancy (attention). METHODS: Visual event-related potentials were recorded during a lexical decision task in which semantic relationship and expectancy (relatedness proportions) were varied. Semantic priming processes were compared between 34 male normal control subjects tested once and 37 male schizophrenic inpatients evaluated during their participation in a double-blind haloperidol maintenance therapy and placebo replacement protocol. RESULTS: Schizophrenic patients failed to discriminate between associated and unassociated words, as measured by the amplitude of the N400 component (i.e., absence of the N400 priming effect); however, the overall mean amplitude of N400 did not differ between patients and control subjects. In addition, patients and control subjects did not differ significantly in the amplitude of N400 elicited to associated words or to unassociated words. Finally, the effect of expectancy-based processing on the magnitude of the N400 priming effect did not differ between patients and control subjects. CONCLUSIONS: On the basis of these findings, a tentative hypothesis is suggested that schizophrenic patients are characterized by a pattern of indiscriminate or random spread of activation in their semantic network during the processing of single-word semantic contexts.

Acoustic Stimulation↗

PubMed1996

Working memory capacity predicts language comprehension in schizophrenic patients.

The association between language comprehension and working memory capacity was evaluated in 25 male DSM-III-R schizophrenic patients (14 inpatients; 11 outpatients), and in 11 male normal controls (no lifetime DSM-III-R disorder). Patients and controls did not differ significantly on age and education. Language comprehension was examined as a function of two types of processing demand: grammatical complexity (complex versus simple sentences) and presentation rate (accelerated versus conversational). Schizophrenic patients showed significantly reduced language comprehension and decreased working memory capacity for language, compared with controls. Patients showed general difficulty in comprehending accurately, rather than exhibiting problems with specific grammatical structures. Subject groups were highly accurate and did not differ in their ability to perceive the individual words in sentences presented at the accelerated rate (intelligibility). Presentation rate and grammatical complexity affected comprehension accuracy in all groups, however, with increases in rate and complexity producing decreases in understanding. Of most importance, theoretically, is the finding that working memory capacity predicted language comprehension accuracy in both schizophrenic patients and normal controls. Results suggest that language comprehension deficits in schizophrenic patients may involve a general dysfunction that is associated with working memory capacity for language.

Adult↗

PubMed1995

Language comprehension in schizophrenia: trait or state indicator?

Language comprehension, measured by the Luria-Nebraska Relational Concepts Factor Scale, was evaluated twice in 15 male DSM-III-R schizophrenic patients during a controlled double-blind haloperidol maintenance (without anticholinergics) and placebo replacement protocol. Fifteen male normal controls were tested once. Patients and controls were matched on age and education. Language comprehension was significantly reduced in patients under both pharmacologic conditions, as compared with controls. Patients' comprehension accuracy did not differ significantly between neuroleptic-treatment and placebo replacement conditions. Patients' comprehension accuracy was independent of positive symptoms, anxiety-depression, measures of clinical course, and CSF and plasma monoamines. Comprehension accuracy was also not associated with patients' educational level or WAIS-R measures of their intellectual and short-term memory functioning. Patients' comprehension performance was significantly associated only with the negative symptom anhedonia-asociality during haloperidol maintenance. Thus, language comprehension in schizophrenic patients was independent of changes in pharmacologic treatment and the positive symptoms of psychosis. Results suggest language comprehension may represent a stable or trait characteristic in schizophrenia.

Adult↗

PubMed1995

Heavy-chain immunoglobulin gene rearrangement and cytoplasmic immunoglobulin expression in acute monocytic leukemia following primary germ cell tumor.

A case of acute monocytic leukemia with rearrangement of the immunoglobulin heavy-chain gene and strong cytoplasmic immunoglobulin expression in a young patient treated with multi-drug chemotherapy for primary seminomatous germ cell tumor 13 months earlier is reported. The short latency period from the beginning of therapy for primary germ cell tumor and the abrupt onset of leukemia with no identifiable prodrome bear similarities to podophyllotoxin-related leukemias.

Adult↗

PubMed1994

[Toxoplasmosis peri-myocarditis as initial manifestation of highly malignant non-Hodgkin's lymphoma].

A case report of a 28-year-old mother of two children with FUO is presented. Physical examination revealed an anemic and febrile woman, who lost 10 kg of weight during the past 3 months. Furthermore, two lymphatic nodes with diameters below 1 cm were detected at the neck and inguinal region. A search for origin of fever including evaluation of foci, malignancies and laboratory investigations was primarily unsuccessful. At day 7 after admission a pericardial murmur could be heard. Echocardiography revealed a pericardial effusion, which increased up to 4 cm during the following days, leading to hemodynamic impairment and asystole. Immediate CR was successful, pericardial effusion was aspirated. Looking for etiology of fever the presence of IgM-antibodies against toxoplasma gondii by an ELISA test was possible. Therefore, toxoplasmosis was diagnosed and a treatment-regimen comprising pyrimethamin and sulfadiazin was initiated. Because of the threat to life and very high titers of C-reactive protein, antibiotic therapy (imipenem) was given additionally. An immunologic impairment was excluded by normal ratio of CD4:CD8 of lymphocytes, normal HIV-test and a nonsuspicious Jamshidi-biopsy of the bone marrow. However, in week 9 after admission lymphatic node-tumors suddenly appeared at the neck and pulmonary hilus. After diagnostic exstirpation a malignant non-Hodgkin-lymphoma (T-cell-type) was diagnosed. It is concluded that in obscure pericardial effusion toxoplasmosis should be considered and that this manifestation may be a precursor of malignant non-Hodgkin-lymphoma.

Adult↗

PubMedDate not supplied

Nursing management innovations: a need for systematic evaluation.

While emphasis in nursing is placed on research on clinical interventions, there has been little attention to the equally important management interventions. The concept of a management intervention or innovation is introduced here and five types of management innovations in nursing are identified. An overview of the research base for four of the innovations demonstrates the need for systematic evaluation.

Diffusion of Innovation↗