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Biomedical subjects

K Maurer

Publications and source records attributed to K Maurer.

At least 73 records · Page 4Linked to original sources
PubMed1995

Anorectal function in fluctuating (on-off) Parkinson's disease: evaluation by combined anorectal manometry and electromyography.

Anorectal dysfunction and constipation are well recognized in Parkinson's disease and may reflect the direct involvement of the gastrointestinal tract by the primary Parkinson's disease process. We hypothesized, therefore, that anorectal function would alter in parallel with fluctuations in motor function related to on- and off-periods in Parkinson's disease, and employed combined anorectal manometry and electromyography to investigate anorectal function during both on- and off-periods in patients with Parkinson's disease. Manometric recordings revealed a deterioration in voluntary sphincter squeeze during off-periods (squeeze index, on versus off, mean +/- SEM: 46.4 +/- 11.1 versus 29.6 +/- 7.9 mm Hg, p < 0.05); correspondingly, simultaneous electromyographic (EMG) recordings showed poor recruitment of external anal sphincter and puborectalis muscles during off-periods. A hypercontractile ("paradoxical") rectosphincteric reflex response occurred during both on- and off-periods, and was associated with an increase in EMG activity in the external sphincter and/or the puborectalis muscle. These changes in manometric and EMG parameters paralleled changes in overall motor function. These findings provide further support for the involvement of the pelvic floor musculature in the Parkinson's disease process and also provide EMG correlates for some of the manometric abnormalities described in Parkinson's disease.

Age of Onset↗
PubMed1995

Correlation between cognitive brain function and electrical brain activity in dementia of Alzheimer type.

Psychometric tests which assess cognitive brain function in dementia disorders are partly prone to artifacts, e.g., the experience of the investigator and the cooperation of the patient influences the results. An objective way to assess the degree of cognitive disturbance could be to measure neuronal activity represented by the electrical brain activity. The aim of the present study was to investigate how well cognitive function in dementia assessed by psychometric tests correlates with electrical brain activity (EEG). Multichannel EEG data was reduced into 3-D intracerebral equivalent dipole EEG generators allowing a more convenient statistical data management and valid physiological data interpretation. 35 patients suffering from dementia of Alzheimer type were investigated. An increase of dipole strength in the slow frequency bands, a more anterior equivalent dipole of alpha- and beta-activity, and a slowing of the EEG with increasing cognitive deterioration could be demonstrated. The results support the hypothesis that the amount of disturbance of cognitive function in dementia can be assessed by measuring the electrical activity of the brain.

Adult↗
PubMed1995

When and how does schizophrenia produce social deficits?

The present study is an empirical contribution to the controversy over whether the poor social performance and lower social class of schizophrenic patients are consequences of the illness, consequences of changes in the individuals predisposed to develop schizophrenia or are due to the adverse social conditions that lead to schizophrenia. The study focuses on the socioeconomic status at onset, on the performance of social roles in the early course of schizophrenia by taking age, gender and the individual level of social development into account. In a representative sample of 232 first episodes of schizophrenia age and type of onset.type and accumulation of symptoms and social functioning in the prodromal and the psychotic prephase and at first admission were assessed and analysed for their predictive power concerning social disability 2 years after first admission. In a case-control study expected and observed social functioning from onset until first admission were compared. The subsequent course was followed up prospectively in five cross sections until 2 years after first admission. In women the age at onset was significantly higher than in men, whereas symptomatology and type of onset showed no gender differences. In 73% of the sample the prodromal phase covered 5 years on average, and the psychotic prephase (until the maximum of positive symptoms) 1.1 years. Deficits in social functioning occurred predominantly during the prodromal and the psychotic prephase. The course over 14 years showed stable group trends in social and symptom measures. By the end of the prodromal phase it was possible to predict social disability 2 years after first admission with a correct classification of 81%. The main factor determining social outcome appeared to be the acquired social status during the prodromal phase of the disorder. The unfavourable early course in men was due mainly to their significantly lower age at onset. These results raise questions concerning an earlier therapeutic and rehabilitative intervention.

Adolescent↗
PubMed1995

Electrical brain activity in schizophrenia described by equivalent dipoles of FFT-data.

Since results of conventional FFT-power-analysis are reference-dependent, only unambiguous neurophysiological data should be used for a functional physiological interpretation of EEG-data. FFT-approximation with successive center-of-gravity-dipole calculation gives unambiguous EEG-data with regard to recording reference. In the present investigation 22 medicated schizophrenic patients were compared with 22 healthy age- and sex-matched controls with regard to spontaneous resting EEG. More anterior and superficial equivalent-dipoles were found in the beta-bands for schizophrenic patients compared to healthy control subjects. There was a tendency of increased beta-activity in schizophrenic subjects. With more severe schizophrenic symptoms (higher BPRS-score), the more anterior was the equivalent-dipole localization in the beta 1-band, and the deeper in the theta-band. The different locations of the beta-band dipoles in schizophrenic patients suggest that different neuronal populations generate beta-activity in schizophrenia compared to healthy controls. FFT-approximation allows a substantial and meaningful data reduction in multichannel recordings and will hopefully help in understanding pathological brain functions in schizophrenia.

Adolescent↗
PubMed1995

Methodological aspects of onset assessment in schizophrenia.

Psychiatric disorders in general and schizophrenia in particular often begin with a prodromal phase progressing into more specific syndromes long before the first treatment contact. More longitudinal studies on course and outcome of schizophrenia begin with first hospital admission not taking into account the preceding early course. The reason for this is the unsurmountable difficulties in observing and assessing real onsets with unspecific symptomatology directly and collecting a sufficient number of 'precontact' cases of rare diseases in the general population. There are in principle two practical ways of assessing time and type of onset and the early course of schizophrenia: the application of a screening procedure for establishing a prospective approach, e.g. the study of individuals at high risk for schizophrenia, and the retrospective assessment of the preceding course carried out at first treatment contact. Methodologically both strategies share the same problems, especially recall bias. In a comprehensive discussion of methodological issues ways are described to reduce and even control recall deficits by using appropriate techniques (standardised assessment with the IRAOS, the 'Interview for the Retrospective Assessment of the Onset of Schizophrenia'; time grids; interval assessment, comparison of independent sources of information etc.). A representative sample of 232 patients with a first episode of schizophrenia were selected from the 276 first admissions of the ABC schizophrenia study taken from a German population of 1.5 million. Results are represented for the crucial questions: when, how and with what symptoms does schizophrenia begin and how does the disorder develop up to the first admission? For example, the gender-specific mean age at different points in time during the development of the disease is presented, and the sequence and cumulation of symptoms in the early course examined. Additionally, the consecutive fulfillment of DSM-III criteria sets for schizophrenic and schizophreniform disorders are presented along with the frequency of different types of onset in schizophrenia.

Adolescent↗
PubMed1995

Effects of the anthelmintics clorsulon, rafoxanide, mebendazole and arprinocid on Echinostoma caproni in ICR mice [corrected and reapublished in J Helminthol 1996 Mar;70(1):95-6].

Female ICR mice, 5 to 6 weeks old, were exposed by stomach tube to 25 metacercarial cysts of Echinostoma caproni per mouse. At 14 days post-exposure, mice were fed by stomach tube clorsulon (1000 mg/kg, 500 mg/kg and 100 mg/kg) or rafoxanide (50 mg/kg, 25 mg/kg and 5 mg/kg) dissolved in dimethylsulphoxide (DMSO) carrier and mebendazole (1000 mg/kg and 500 mg/kg) or arprinocid (100 mg/kg and 50 mg/kg) suspended in a 2:1 polyethylene glycol (PEG)/DMSO carrier. All drugs were obtained from Merck Inc. (Rahway, New Jersey, USA) and only single dose regimes were used. Experimentally infected mice that served as controls received either DMSO or 2:1 PEG/DMSO carriers or were not given the carrier. Mice were necropsied 15v, 16, 18 and 20 days postexposure to worms. Doses of 100 mg/kg of clorsulon and 50 mg/kg of rafoxanide were 100% effective in eliminating the echinostomes on day 1 post-administration of the anthelmintics. Mebendazole and arprinocid were ineffective in eliminating worms at 1 or 2 days post drug administration.

Adenine↗
PubMed1995

Symptom assessment in casenotes and the clinical diagnosis of schizophrenia.

It is well known from several international studies that the incidence rates for schizophrenia, based on first-admission samples, are low in Denmark, especially in females, compared with other countries. This might be due to special diagnostic traditions in Denmark. To analyze how Danish psychiatrists reach a diagnosis of schizophrenia, a stratified subsample of 122 cases out of all 1,259 patients, aged between 12 and 64 years, with a first hospital admission in 1976 under the diagnosis of schizophrenia, paranoid psychosis, acute reactive paranoid psychosis, or casus limitaris was selected. For this subsample, psychopathological symptoms, as documented in the clinical casenotes, were rated by PSE-9 symptom lists for subsequent CATEGO analysis. The core syndrome of schizophrenia, as defined by the CATEGO class S+, showed no association with the clinical schizophrenia diagnosis compared with the other diagnoses mentioned. Also, positive symptoms of schizophrenia did not determine the diagnosis, but for typical negative symptoms such associations were indicated. Some negative symptoms also seemed to be linked to a depressive state. Furthermore, the present work indicates that using first-admission data leads to a higher age at schizophrenia onset and a lower first-admission rate in Denmark compared with Germany.

Adolescent↗
PubMed1995

[Cat scratch disease caused by Bartonella henselae].

Bartonella henselae is an etiologic agent of cat-scratch disease and, in immunocompromised patients, of bacillary angiomatosis and other severe syndromes. Cat-scratch disease usually presents as lymphadenopathy, which resolves spontaneously within 2-4 months. The utility of antibiotic therapy remains controversial. In Tyrol four cases of human cat-scratch disease were diagnosed in children in 1994, yielding a prevalence of 0.7/100,000 per year. A 3-year-old boy had lymphadenitis coli since one year despite antituberculosis therapy which was initiated because of the histopathological picture and a positive tuberculin reaction (despite negative mycobacteria-cultures and -PCR). Two girls, age 9 and 13 years, had lymphadenitis at upper or lower extremities after cat-scratches from kittens. A 13-year-old boy presented with febrile illness and right hip pain, computer tomography revealed an osteolytic lesion; symptoms subsided within 3 weeks. Diagnosis of cat-scratch disease is based on cat contact, negative studies for other similar diseases, characteristic histopathologic features (if available), and results of an indirect immunofluorescence test (antigen: Houston-1 isolate, ATCC 49882). We believe that the availability of this serological test will increase the number of diagnosed cases of human Bartonella henselae infections.

Adolescent↗
PubMed1994

P300 in schizophrenia: interactions between amplitudes and topography.

Low P300 amplitudes and topographical asymmetries have been reported in schizophrenic patients, but reference-independent amplitude assessment failed to replicate reduced amplitudes. P300 amplitude is conventially assessed at midline electrodes (Pz), and asymmetric topography as reported in schizophrenics, may confound this measurement. We investigated the possible interaction between P300 topography and assessments of amplitudes. In 41 clinically stable schizophrenics and 31 normal controls, the general finding of reduced amplitudes at the Pz-electrode and topographical asymmetries in the patient group were replicated. In both groups, asymmetries of the P300 field (lateralized peaks) reduced the standard amplitude assessment at the midline parietal electrode, but did not affect the reference-independent, global amplitude assessment. This shows that asymmetry per se does not imply reduced field strength. In addition, in schizophrenics, but not in controls, there was a significant effect of the direction of asymmetry on both amplitude measures, amplitudes being lower with increasing shift of the P300 peak to the right side. Considering also the slightly left-lateralized peaks in the normal controls, this suggests that only right-lateralized P300 peaks express functional deficits in schizophrenics, whereas left-lateralized peaks fall within the physiological variability of the P300 field. The reference-independent amplitude assessment is proposed for unambiguous amplitude assessment in order to better define the clinical, psychological and physiopathological meaning of the P300 alterations in schizophrenics.

Adult↗
PubMed1994

P300 asymmetries in schizophrenia revisited with reference-independent methods.

Evidence of hemispheric asymmetries in schizophrenia has been reported from different research areas. Asymmetries in evoked potential P300 topography are still controversial because of inconsistent findings. In the present study, previous results of abnormal lateralization of P300 were replicated in stabilized residual schizophrenic patients. Auditory P300 was recorded during an oddball task in which subjects detected rare target stimuli. Schizophrenic patients had the P300 peak shifted to the right hemisphere and differed significantly from age- and sex-matched normal control subjects who had left-lateralized P300 peaks. A comparison of different methods of assessment and analysis of the topographical features of the P300 electric fields showed that the extraction of reference-independent descriptors of P300 topography is a reliable and sensitive method for statistical handling of the maps. The results suggest left hemispheric dysfunction during cognitive tasks in a subgroup of schizophrenic patients. Inconsistencies between previous studies are likely to be due to heterogeneous patient groups, which may have included patients in an acute schizophrenic episode or patients in clinical remission. Investigation of the clinical meaning of P300 alterations requires careful psychopathological definition of the patient groups.

Adult↗
PubMed1994

Event-related potentials and psychopharmacology. Cholinergic modulation of P300.

The event-related potential P300 probably reflects the encoding of information into short-term memory. Anatomical structures of the limbic system are involved in this process. Since the same structures are involved in the generation of the event-related potential P300, P300 is thus well suited to assess pharmacological influence on memory functions and cognitive processes, for example, by changing the availability of neurotransmitters like acetylcholine at their respective receptors.

Adult↗
PubMed1994

[Depression in the early course of schizophrenia].

Depressive syndromes in schizophrenia are reported in the prodromal stage of the early course, during the first or later psychotic episodes, but also after the fading out of an acute episode and as a precursor of relapse. According to these multiple conditions several explanations also exist as to how to understand depression in schizophrenia. Some authors interpret it as an elementary part of the schizophrenic symptomatology, which is only masked by positive symptoms (revealed depression). However, it can also be understood as a reactive depression or as caused by neuroleptic treatment, as part of the negative syndrome or as co-morbidity. In the ABC-Schizophrenia-Study, depression in the early course was analysed for patients in their first psychotic episode at index admission and an ICD-9 diagnosis of schizophrenia (ICD 295). In 81% of this sample depression was observed, beginning on average 4.3 years prior to index admission. In 42% of the patients depression began in the prepsychotic phase. In 18% the positive and the depressive syndrome developed within one month, and in 21% depression started after the first positive symptom occurred. We could only observe a clear sequence of depressive, negative and positive symptoms in the subgroup characterised by prepsychotic depression. A clear order of negative and positive symptoms was not observed in the other groups. Patients without depression in the early course have lower symptom levels at index admission. They present less positive symptoms (CATEGO-subscore DAH), fewer behavioural disturbances (subscore BSO) and also lower scores of non-specific symptoms (subscores SNR and NSN). More than 80% of the patients with depression in the early course also had a simple depression (as defined by the CATEGO-syndrome SD). Contrary to this, only 20% of the patient group without depression in the early course have positive SD values. Comparable percentages of males and females have depression in the early course, but in females depression begins more frequently in the prepsychotic phase, whereas in the male subgroup it more often starts postpsychotically, i.e. after the onset of the first psychotic symptom.

Adult↗
PubMed1994

Can estradiol modulate schizophrenic symptomatology?

Using epidemiologic data, in an earlier study we formulated the hypothesis that estrogens can delay the onset of schizophrenia in females by raising the vulnerability threshold for this disease. In animal experiments, Häfner and colleagues found evidence that chronic estradiol treatment reduces the sensitivity of dopamine (D2) receptors in the brain. In the clinical study presented in this article, as a further step we examined the antipsychotic properties of estradiol in human females by testing whether schizophrenic symptomatology varies with estradiol serum levels throughout the menstrual cycle. We examined 32 acutely admitted female schizophrenia patients (Present State Examination/CATEGO diagnosis, ICD-9) with a history of regular menstrual cycles, ages 18 to 43 (mean = 30.5), during their hospital stays (3-8 weeks), analyzing hormonal parameters and applying various rating scales for psychopathology every 7 days. In all patients, estradiol serum levels were markedly reduced as compared with the normal population, and fluctuations throughout the cycle were dampened. Nevertheless, a significant association emerged between estradiol levels, on the one hand, and psychopathology scores, on the other--that is, the psychiatric symptomatology as assessed by the clinical psychiatrist (Brief Psychiatric Rating Scale, p < or = 0.01), behavior on the ward as assessed by the nursing staff (Nurses' Observation Scale for Inpatient Evaluation p < or = 0.01), paranoid tendencies and general well-being as assessed by the patients themselves (Paranoid-Depressivitäts-Skala paranoid score p < or = 0.05; Befindlichkeits-Skala p < or = 0.05). Psychopathology seems to improve when estradiol levels rise, and vice versa. These findings can be interpreted as further evidence for a protective effect of estrogens in schizophrenia, possibly due to the known anti-dopaminergic activities of these hormones.

Adolescent↗
PubMed1994

Validation of Danish case register diagnosis for schizophrenia.

The ABC schizophrenia study aims at investigating sex differences in age of onset, symptoms and course of schizophrenic and paranoid disorders. For this purpose, we used case register data from Denmark and Mannheim and a directly examined sample of first admissions (ABC sample). The Danish case register sample included less clinical diagnoses of schizophrenia and more schizophrenia-related disorders (acute paranoid reaction, paranoid states and borderline schizophrenia) than the Mannheim data (case register and ABC sample). The problem therefore was whether the two datasets are comparable and the results are valid. For this reason a randomized, stratified sample of 116 patients was drawn from the Danish case register sample. The case notes of these 116 patients were requested from the hospitals where the patients had been treated and analyzed by means of a scoring sheet based on the Interview for the Retrospective Assessment of the Onset of Schizophrenia (IRAOS). The use of operationalized diagnoses of the CATEGO program, based on PSE items, which are integrated in IRAOS, demonstrated that the samples of the Danish and the Mannheim case registers and the directly investigated ABC sample have comparable diagnostic distributions. Possible explanations for the differences between the clinical and the CATEGO diagnoses in the Danish case register may be the frequent use of diagnoses of borderline schizophrenia and reactive psychoses (previously called psychogenic psychoses), and above all a more narrow concept of schizophrenia; in Denmark, schizophrenia is diagnosed relatively late, i.e., after the presence of enduring negative symptoms, and thus mostly after the appearance of residual state.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

The epidemiology of early schizophrenia. Influence of age and gender on onset and early course.

For the investigation of the early course of schizophrenia starting from onset, the standardised Interview for the Retrospective Assessment of the Onset of Schizophrenia was developed and validated. In a representative sample of 267 first-admitted German schizophrenics of a broad diagnosis from a population of 1.5 million, the age at which different diagnostic and onset definitions were satisfied, the symptoms at the time of the interview, and the accumulation of positive and negative symptoms until first admission were assessed. Comparison between the two sexes and three age groups yielded hardly any differences in the accumulation of symptoms and their course until first admission, except for a slightly shorter period of negative symptoms in young males and a slightly longer one in older women--which contradicts prevailing opinion. At the time of the interview, no significant sex differences were found with respect to the core symptoms of schizophrenia (negative and first-rank symptoms), but clear and substantial differences emerged in disease behaviour. The significantly higher age at first onset in women is explained, on the basis of animal experiments and a clinical study, by the neuromodulatory effect of oestrogen on D2 receptors and by a higher vulnerability threshold in women.

Adolescent↗
PubMed1993

Structure of the ABF1-homologue from Kluyveromyces marxianus.

By transformation of a Saccharomyces cerevisiae mutant strain conditionally expressing the ABF1-gene, a Kluyveromyces marxianus DNA fragment carrying the gene encoding the ABF1-homologue of this yeast strain (KmABF1) was selected. Comparison of the sequence of the KmABF1 gene with that encoding Saccharomyces cerevisiae ABF1 and the previously isolated ABF1-gene from Kluyveromyces lactis (KlABF1) revealed distinct regions displaying considerable homology and therefore most likely representing sequences encoding essential domains. In addition to the domains putatively involved in DNA binding of the protein factor, two short conserved amino acid sequence elements at the C-termini of the homologous proteins were identified, which are proposed to play a part in their trans-acting functions. This is the first report on the structure of a regulatory protein factor from K. marxianus.

Amino Acid Sequence↗