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Biomedical subjects

S Moritz

Publications and source records attributed to S Moritz.

At least 37 records · Page 2Linked to original sources

[Association norms for 68 German homonyms].

Norms for 68 German homophonic homographs were collected in a normal population comprising 100 subjects. Frequency and polarity as well as U-scores (index of ambiguity) are presented. 49 of the words revealed a clear dominance for only one meaning. 7 homophonic homographs were balanced, and for 12 words less than 5% of all associations were given for each of the inferior meanings. Studies 2a and 2b are a replication of previous findings on the resolution of semantic ambiguity. Inhibition effects were revealed for discordant triplet conditions which contained a long interstimulus interval between homograph and target, whereas an (insignificant) facilitation effect occurred for trials with a shorter interval. Results of study 2 are in line with context-sensitive models which claim that after the initial activation of all meanings of a homograph a context-guided process leads to a suppression of context-irrelevant homograph information.

Adult↗

Impaired modulation of the saccadic contingent negative variation preceding antisaccades in schizophrenia.

BACKGROUND: The contingent negative variation (CNV) is considered to reflect prefrontal functioning and can be observed before manual and ocular motor responses. Schizophrenic patients exhibit reduced CNV amplitudes in tasks requiring manual motor responses. A number of studies has also found normal prosaccades, but delayed antisaccades and an augmented rate of erroneous prosaccades during the antisaccade task in schizophrenia. In this study we examined the CNV during pro- and antisaccade tasks in schizophrenic patients and healthy control subjects. METHODS: Data of 17 medicated schizophrenics (ICD-10, F20) and 18 control subjects, matched with patients for age, gender, and education were analyzed. Horizontal pro- and antisaccades were elicited in four blocks, each consisting of 80 trials. Electroencephalogram was recorded from 32 channels with a DC amplifier. RESULTS: Patients exhibited delayed correct responses and more erroneous prosaccades during the antisaccade task than control subjects, but normal prosaccadic reaction times. In control subjects, the vertex-predominant saccadic CNV was generally larger than in patients, and larger during the anti- than during the prosaccade task. This task-related amplitude augmentation was absent in patients. Analyses of additional components suggested specificity of impaired event-related potential modulation to the saccadic CNV. CONCLUSIONS: In accordance with the presumed prefrontal dysfunction, our results suggest deficient preparation and execution of antisaccades in schizophrenia.

Adult↗

[Conversion from typical to atypical neuroleptics. Guidelines for ambulatory and inpatient treatment].

The introduction of atypical antipsychotics has presented new options for the pharmacological treatment of schizophrenic patients. It is assumed that in the near future, neuroleptic medication will shift from conventional to atypical antipsychotics for an increasing number of patients. The present article addresses guidelines for the conversion from conventional to atypical neuroleptics in inpatient and outpatient settings.

Ambulatory Care↗

Haemoglobin interferes with the ex vivo luciferase luminescence assay: consequence for detection of luciferase reporter gene expression in vivo.

The luciferase reporter gene is a useful tool for determining the efficacy of transfection of plasmid DNA and adenovirus-mediated gene transfer in vivo. However, we report here that the haemoglobin present in tissue samples can mask the detection of the luciferase activity and lead to underestimation of the luciferase levels. We evaluated the degree of interference in different organ samples of mice and investigated the possibilities for removal of haemoglobin from tissue samples by: (1) perfusion of the whole animal; (2) different hypotonic treatments lysing preferentially red blood cells; and (3) chromatographic separation. Removal of haemoglobin resulted in significantly improved detection of luciferase activity from tissue samples. The results indicate that the luciferase activity determined in tissue samples may not reflect the actual level of reporter gene expression, if contaminating blood is not taken into consideration.

Adenoviridae↗

Dosage of conventional neuroleptic medication and subjective cognitive functioning in schizophrenia.

Subjective cognitive and perceptual disturbances as assessed with the Frankfurt Complaint Questionnaire (FCQ) were correlated with chlorpromazine equivalents in 40 schizophrenic inpatients, who were treated with conventional neuroleptics. In line with previous research using 'objective' neuropsychological tests, both correlations and partial correlations (controlling for the effects of psychopathology, extrapyramidal symptoms and length of illness) confirmed that higher neuroleptic doses significantly worsen several cognitive and perceptual domains (r = 0.44 -0.54; P < or = 0.005 -0.05) with the possible exception of mnestic functions (r = 0.21 -0.24, n.s.) and language (r = 0.37 -0.38, P < 0.1). The clinical importance of self-report scales for evaluating both the risks and benefits of neuroleptic treatment is discussed.

Adult↗

Increased automatic spreading activation in healthy subjects with elevated scores in a scale assessing schizophrenic language disturbances.

BACKGROUND: Previous studies on semantic priming have suggested that schizophrenic patients with language disturbances demonstrate enhanced semantic and indirect semantic priming effects relative to controls. However, the interpretation of semantic priming studies in schizophrenic patients is obscured by methological problems and several artefacts (such as length of illness). We, therefore, used a psychometric high-risk approach to test whether healthy subjects reporting language disturbances resembling those of schizophrenics (as measured by the Frankfurt Complaint Questionnaire subscale 'language') display increased priming effects. In addition, the Schizotypal Personality Questionnaire was used to cover symptoms of schizotypal personality. Enhanced priming was expected to occur under conditions favouring automatic processes. METHODS: One hundred and sixty healthy subjects performed a lexical decision semantic priming task containing two different stimulus onset asynchronicities (200 ms and 700 ms) with two experimental conditions (semantic priming and indirect semantic priming) each. RESULTS: Analyses of variance revealed that the Frankfurt Complaint Questionnaire-' language' high scorers significantly differed from low scorers in three of the four priming conditions indicating increased automatic spreading activation. No significant results were obtained for the Schizotypal Personality Questionnaire total and subscales scores. CONCLUSIONS: In line with Maher and Spitzer it is suggested that increased automatic spreading activation underlies schizophrenia-typical language disturbances which in our study cannot be attributed to confounding variables such as different reaction time baselines, medication or length of illness. Finally, results confirm that the psychometric high-risk approach is an important tool for investigating issues relevant to schizophrenia.

Adult↗

Effect of simian virus large T antigen expression on cell cycle control and apoptosis in rat pleural mesothelial cells exposed to DNA damaging agents.

Cell cycle progression and apoptosis are controlled by regulatory proteins, including p53, of which functional alterations are linked to carcinogenesis. Recently, malignant mesothelioma (MM), a primary tumour related to asbestos exposure, alternatively to post therapeutic radiations, has proven to be an important problem in oncogenesis. The p53 protein does not seem mutated or deleted in MM but a possible inactivation by binding to other proteins [mdm2; SV40 large T antigen (Tag)] has been suggested. The present work investigated cell cycle regulation in normal rat pleural mesothelial cells (RPMC) and in RPMC expressing Tag (RPMC-TSV40), under exposure to asbestos and radiations. In RPMC, these agents induced activation of cell cycle checkpoints located at G1/S and G2/M and/or mitosis but a lack of control at G1/S was found in RPMC-TSV40. A loss of G2/M control may account for the formation of micronuclei observed after exposure of RPMC-TSV40 to radiations. In RPMC-TSV40 the enhancement of abnormal mitoses and apoptosis after asbestos exposure, in comparison with RPMC, suggests a loss of mitotic control and a p53-independent mechanism of apoptosis. Thus Tag expression in mesothelial cells might have both adverse and beneficial effects by impairing the control of DNA integrity and enhancing apoptosis respectively.

Animals↗

SV40-like DNA sequences in pleural mesothelioma, bronchopulmonary carcinoma, and non-malignant pulmonary diseases.

Pleural and pulmonary malignancies are usually associated with well-known carcinogen exposure. Recently, the presence of simian virus 40 (SV40)-like DNA sequences has been detected in brain and bone-related human cancers and in pleural mesothelioma. In order to determine whether SV40-like DNA sequences are also present in bronchopulmonary carcinoma and non-malignant lung samples, 125 frozen pleural and pulmonary samples (including 21 mesotheliomas, 63 bronchopulmonary carcinomas, 8 other tumours, and 33 non-malignant samples) and 38 additional samples distant from tumours were studied for the occurrence of SV40-like DNA sequences by polymerase chain reaction (PCR) amplification followed by hybridization with specific probes. Sequences related to SV40 large T antigen (Tag) were present in 28.6 per cent of bronchopulmonary carcinomas, 47.6 per cent of mesotheliomas, and 16.0 per cent of cases with non-neoplastic pleural and pulmonary disease. No statistically significant difference in the occurrence of these DNA sequences was found between malignant mesothelioma and bronchopulmonary carcinoma, but a significantly higher number of mesothelioma cases exhibited SV40-like DNA sequences in comparison with cases of non-malignant pleural or pulmonary disease (P < 0.04). Among cases positive for SV40-like DNA sequences, a history of asbestos exposure was found in 3 out of 12 bronchopulmonary carcinomas and 8 out of 10 mesotheliomas. Immunohistochemistry using monoclonal antibodies directed against Tag did not demonstrate nuclear staining. The DNA sequences were not related to BK virus sequences, but three samples were positive with probes hybridizing with JC virus DNA sequences. In conclusion, this study demonstrates the presence of SV40-like DNA sequences in pulmonary neoplasms and in non-malignant lung tissues. It appears that the presence of SV40-like DNA is not unique to cancer.

Adult↗

Expression, purification, and encephalitogenicity of recombinant human myelin oligodendrocyte glycoprotein.

Myelin oligodendrocyte glycoprotein (MOG), a putative autoantigen in multiple sclerosis (MS), is a quantitatively minor component of the CNS. In view of the difficulties associated with the purification of MOG from brain tissues, the extracellular domain of human MOG corresponding to the N-terminal 121 amino acids was expressed in Escherichia coli as a glutathione sulfotransferase fusion protein. The expressed protein was localized to inclusion bodies, and varying the growth parameters resulted in the solubilization of small amounts of GST-MOG that could be affinity purified on glutathione agarose columns. The fusion protein found in the inclusion bodies could be solubilized with urea. The solubilized fusion protein was cleaved with thrombin, and the extracellular domain was purified by CM Sephadex 50 chromatography to homogeneity. Injection of recombinant human MOG into different strains of mice resulted in the induction of an MS-like disease, characterized by severe neurological impairment and extensive CNS demyelinated lesions. Recombinant MOG produced in E. coli should prove to be useful as a highly purified biological reagent for immunological, pathological, functional, and structural studies.

Animals↗

Effects of adenosine on cardiopulmonary functions and oxygen-derived variables during endotoxemia.

OBJECTIVES: To determine the effects of a prophylactic intravenous infusion of adenosine on cardiopulmonary functions and oxygen-derived variables in a porcine model of endotoxemia. DESIGN: Prospective, randomized, placebo-controlled, unblinded study. SETTING: University research laboratory. SUBJECTS: Thirty country bred pigs, aged 6 to 7 wks, weighing 24.9 +/- 0.65 (SEM) kg body weight. INTERVENTIONS: Pigs were anesthetized by i.v. pentobarbital and fentanyl, intratracheally intubated, and mechanically normoventilated with a gas mixture of nitrous oxide/oxygen = 1:1. Intravascular catheters were inserted to allow for determination of arterial, central venous blood pressure, pulmonary artery occlusion pressure, cardiac output, and sampling of blood for gas analyses. Group 1 (n = 10) received a 330-min intravenous infusion of Salmonella abortus equi endotoxin (5 microg/kg body weight x hr). Group 2 (n = 10) received an additional intravenous infusion of adenosine (150 microg/kg body weight x min), started 30 mins before the infusion of endotoxin. Control groups 3 and 4 (n = 5 for both groups) received adenosine or physiologic saline, respectively. MEASUREMENTS AND MAIN RESULTS: Parameters of cardiopulmonary function and oxygen-derived variables were calculated from pulmonary artery catheter measurements and blood gas analyses using standard formula. Plasma concentrations of purine compounds (adenosine, inosine, hypoxanthine) were determined by high-performance liquid chromatography. Since tumor necrosis factor-alpha plays a central role in the development of endotoxic shock, concentrations of this cytokine were determined in serum by enzyme-linked immunosorbent assay. Infusion of adenosine before the beginning of the infusion of endotoxin increased plasma concentrations of the nucleoside from 193 +/- 72 to 553 +/- 65 nmol/L and decreased the systemic vascular resistance by 50%. Although acting as a potent vasodilator under control conditions, adenosine did not aggravate the arterial hypotension elicited by endotoxemia but significantly increased cardiac output by a comparably small decrease in systemic vascular resistance, prevention of pulmonary vasoconstriction, and improvement of left ventricular performance. Despite significant pulmonary vasodilation, gas exchange was not worsened but slightly improved by adenosine. With the increase in cardiac output and arterial oxygenation, systemic oxygen delivery almost doubled. This adenosine-induced oxygen flux was not a surplus but was most likely utilized by tissues, as suggested by the much earlier beginning of the increase in the systemic oxygen consumption and the attenuation of the decrease in the gastric mucosal pHi. No effects of adenosine were observed on the endotoxin-induced increase in serum concentrations of tumor necrosis factor-alpha. CONCLUSIONS: Infusion of adenosine might be useful to improve flow-dependent oxygen delivery and tissue oxygenation during endotoxic shock without the induction of adverse cardiopulmonary side effects. The beneficial hemodynamic effects of adenosine appear not to be mediated by the inhibition of the release of tumor necrosis factor-alpha.

Adenosine↗

Buflomedil hydrochloride reduces systemic activation of polymorphonuclear leukocytes during hyperdynamic endotoxemia.

The purpose of the study was to examine the effects of buflomedil hydrochloride (BFL) on the expression of adhesion molecules (beta2-integrins) and oxygen radical production of circulating and emigrated intra-abdominal polymorphonuclear leukocytes (PMNL) in a standardized porcine model of hyperdynamic endotoxemia. A total of 20 anesthetized pigs were randomly assigned to one of the following groups: endotoxin group (endotoxin 5 microg / kg x h, intravenously (i.v.), n = 7), BFL group (BFL (3 mg/kg initial i.v. bolus followed by a continuous infusion (.1 mg / kg x h) and endotoxin 5 microg / kg x h, i.v., n = 7), and control group (NaCl .9%; n = 6). Experiments were terminated at 330 min. Infusion of endotoxin alone resulted in the activation of circulating and emigrated PMNL as evidenced by neutropenia, functional and numerical up-regulation of beta2-integrins, and enhanced oxygen radical production. BFL was able to attenuate functional and numerical up-regulation of beta2-integrins as well as oxygen radical production of circulating and emigrated PMNL. An unexpected decrease in the plasma concentration of BFL during the experiments was associated with an increase in the oxygen radical production of PMNL at the end of the experiments. In addition, BFL attenuated the fall in the intramucosal pH and the increase in plasma concentration of lactate observed in the late phase of endotoxemia. These findings suggest that BFL is able to decrease systemic activation of PMNL and to improve local tissue oxygenation during endotoxemia.

Animals↗

Detection of SV40-like DNA sequences in pleural mesothelioma, bronchopulmonary carcinoma and other pulmonary diseases.

Mesotheliomas are pleural-based tumours mainly associated with asbestos exposure (70% of cases) and the incidence is still raising. Recently, a possible viral connection was reported and 60% of mesotheliomas were demonstrated to contain and express SV40-like DNA sequences. In this study, the presence of SV40-like DNA sequences were investigated in mesotheliomas (15 tissue samples and six cell lines) and in 63 additional bronchopulmonary carcinomas, one parietal osteosarcoma and non-malignant lung samples as well as in organizing pleuritis (8). Finally, 163 samples were analysed by the polymerase chain reaction (PCR) with a set of primers PYV.for and PYV.rev to amplify a 173 bp region of the SV40 Tag. and a 179 bp region JC virus (JCV) as well as a 182 bp region BK virus (BKV). PCR amplification and hybridization with a probe specific for SV40 Tag revealed that 47.6% of mesotheliomas, 28.6% of primary bronchopulmonary carcinomas and 16% of non-neoplasic lung diseases contained SV40-like DNA sequences. No statistically significant difference in the occurrence of these DNA sequences was found between malignant mesothelioma and bronchopulmonary carcinoma. However, a significantly higher number of mesothelioma cases exhibited SV40- like DNA sequences in comparison with non-malignant pleural and pulmonary tissues. The DNA sequences were not related to BK and JC virus sequences. These results indicate that SV40-like DNA sequences are present in mesotheliomas as well as in bronchopulmonary carcinomas and non-malignant pleuropulmonary diseases.

Antigens, Polyomavirus Transforming↗

Variation in management of small invasive breast cancers detected on screening in the former south east Thames region: observational study.

OBJECTIVE: To examine the variation in surgical and adjuvant treatment of breast cancer of known histology and detected on screening in a large cohort of patients treated by the surgeons of a health region. DESIGN: Part prospective, part retrospective observational study using the databases of a region's breast screening programme and of the cancer registry. SETTING: The former South East Thames region. SUBJECTS: 600 women aged 49-79 who presented during 1991-2 with invasive breast cancer up to 20 mm in diameter that had been detected on screening. These patients were treated by 35 surgeons. MAIN OUTCOME MEASURES: Mastectomy rate by surgeon and the use of adjuvant treatment (radiotherapy, tamoxifen, and chemotherapy) were compared with risk factors, tumour grade, resection margins, and axillary node status. RESULTS: The mastectomy rate varied between nil and 80%, although the numbers at these extremes were small (0/13 v 8/10). Surgeons operating on more than 20 such cases had a lower mastectomy rate (15%) than surgeons treating fewer cases (23%), but this difference was confounded by variation in casemix. There were also wide variations in mastectomy rates and in axillary sampling rates that were independent of casemix or caseload. There was broad agreement on the use of adjuvant tamoxifen (94%), but few patients received chemotherapy (2.5%). 78 patients (19%) did not receive radiotherapy, including 51 out of 317 patients with unfavourable tumours, and 26 patients did not receive tamoxifen. Whether the patient received adjuvant treatment was more dependent on referral by the surgeon than the risk factors for local recurrence and was independent of caseload. CONCLUSION: Mastectomy rates for similar tumours vary widely by surgeon independently of casemix or caseload, but surgeons with a higher caseload tend to have a lower mastectomy rate. Omission of postoperative radiotherapy or tamoxifen after conservative treatment is not related to risk factors for local recurrence or caseload. Confidential feedback of treatment profiles to individual surgeons has been used, but when benefit has been established treatment should be guided by evidence based protocol.

Aged↗

Reduced cognitive inhibition in schizotypy.

OBJECTIVES: The relationship between negative priming and the positive symptoms of schizotypy was investigated. It was hypothesized that high schizotypes would display less negative priming than low schizotypes. A further important aim of the study was to disentangle the modalities involved in negative priming performance, since a reduction in negative priming, as revealed by schizophrenics and schizotypes, might reflect a failure to actively inhibit irrelevant information (cognitive inhibition) as well as dyslexia or a general slowness in information processing. DESIGN: A paper test based on the German version of the Stroop test was used to measure negative priming. A baseline condition of the test, colour word reading, that has proven to be a valid indicator of dyslexia was used to measure the influence of reading disturbances on negative priming. Additionally, a priming condition, termed inverted priming, in which the target of a stimulus is identical with the distractor in the subsequent stimulus, was employed. METHODS: Fifty healthy adults were drawn from the general population. After neuropsychological assessment participants completed a battery of schizotypal questionnaires. Correlational analyses and mean comparisons were used to investigate the relationship between neuropsychological data and schizotypy. RESULTS: Results suggest that reduced negative priming is related to positive schizotypy. Reduced negative priming in high schizotypes was unrelated to dyslexia, and found unlikely to be affected by deficits in early processing. The inverted priming condition produced comparatively fewer errors in high schizotypes. CONCLUSIONS: Results support the hypothesis that reduced cognitive inhibition may underlie positive schizotypal symptomatology.

Adolescent↗

Effects of adenosine on the functions of circulating polymorphonuclear leukocytes during hyperdynamic endotoxemia.

Endotoxin-activated polymorphonuclear leukocytes (PMNL) adhere to the vascular endothelium and cause damage by the release of toxic superoxide anions (O2-). Because adenosine is a potent inhibitor of PMNL in vitro, the present study investigates the effects of this nucleoside on the functions of circulating PMNL in a standardized porcine model of hyperdynamic endotoxemia. Ten anesthesized pigs received an intravenous (i.v.) 330-min infusion of endotoxin (5 microg/kg of body weight per h). Another 10 pigs were also infused with endotoxin plus adenosine (150 microg/kg/min [i.v.]); this treatment was begun 30 min prior to the beginning of endotoxin treatment. Control groups (five animals per group) received either adenosine or physiological saline. Infusion of endotoxin caused severe neutropenia, shedding of L-selectin, upregulation of beta2-integrins, increased binding of C3-coated zymosan particles, and subsequent phagocytosis by PMNL. While phagocytosis-induced production of oxygen radicals appeared to decrease, extracellular release of superoxide anions was strongly enhanced. Infusion of adenosine during endotoxemia had no effect on neutropenia, expression of adhesion molecules, C3-induced adhesion, phagocytosis, or intracellular production of oxygen radicals, whereas extracellular release of O2- was strongly inhibited. Thus, i.v. infusion of adenosine during endotoxemia could be useful in protecting from O2(-)-mediated tissue injury without compromising the bactericidal mechanisms of PMNL.

2-Chloroadenosine↗