Biomedical subjects

H Danker-Hopfe

Publications and source records attributed to H Danker-Hopfe.

At least 19 recordsLinked to original sources

PubMed2006

Differential regulation of nerve growth factor and brain-derived neurotrophic factor in a mouse model of learned helplessness.

Stress-induced helplessness in rodents constitutes a well-defined model to investigate neurobiological mechanisms of depression. Neurotrophins like nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) have both been shown to be involved in neurobiological changes of physiological and pathological reactions to stress. In this study we investigated NGF and BDNF protein levels in the frontal cortex and hippocampus in mice treated with an established model of inducible helplessness via electric footshocks compared to untreated controls at various times (0 h up to 14 days after treatment). NGF levels were transiently decreased by one forth in the frontal cortex of shocked mice at 6 h after the stress treatment, whereas BDNF levels remained unchanged in the brain areas investigated throughout the time course. In addition, frontal cortex BDNF levels showed a significantly higher concentration in the right compared to the left hemisphere (up to 3-fold). This effect was detectable independently of treatment, namely in shocked and control mice at any time point measured. In conclusion, a transient decrease of frontal NGF constitutes the most striking correlate of neurobiological changes in this animal model of stress-induced change of behaviour. Interhemispherical differences of BDNF content in the frontal cortex are a new finding that might reflect intracerebral side dominance. Thus, subsequent studies of frontal cortex BDNF expression should carefully consider an interhemispherical variance to avoid misinterpretation.

Animals↗

PubMed2006

The effect of donepezil on sleep in elderly, healthy persons: a double-blind placebo-controlled study.

INTRODUCTION: Previous research in younger individuals has shown that acetylcholinesterase inhibitors tend to enhance REM sleep. METHODS: Forty-two healthy elderly persons participated in a double-blind placebo-controlled polysomnographic study (parallel group design). RESULTS: The present study indicates that in the elderly persons, donepezil, an acetylcholinesterase inhibitor also exerts a marked effect on REM sleep parameters: REM density was increased whereas REM latency was reduced, thus, confirming the findings of our pilot study described earlier. CONCLUSION: Whether the cholinergic stimulation measured by polysomnography is related to treatment efficacy is a very interesting but an open question. Based on the findings that REM sleep is associated with memory consolidation, the question whether REM sleep augmentation enhances memory performance-as suggested by the findings of the pilot study-seems to be an interesting topic for future research.

Aged↗

PubMed2003

No nerve growth factor response to treatment with memantine in adult rats.

Nerve growth factor (NGF) is the most widely examined neurotrophin in the experimental models of Alzheimer's disease (AD) and has been shown to prevent the retrograde degeneration of cholinergic neurons. In this study we examined NGF and cholineacetyltransferase (ChAT) changes in several rat brain regions after excitotoxic lesion of the entorhinal cortex with quinolinic acid and tested the effect of memantine on spatial learning in the radial maze after lesion. We observed a significant increase (+26%, p=0.02) of NGF concentrations in the hippocampus of the lesioned rats when compared to sham-lesioned rats. Chronic treatment with memantine showed no significant effect on the NGF increase in the hippocampus (p=0.72). The ChAT activity was significantly increased in the lesioned rats when compared to controls (+16%, p<0.05) and did not depend on treatment with memantine. In spite of this, memantine improved performance of the radial maze. This indicates that memory improving effects of memantine observed in experimental animals and in clinical studies are probably not related to changes in brain NGF content, whereas the observed NGF increase in the denervated hippocampus is probably trauma-related reflecting impaired retrograde transport of hippocampal NGF.

Animals↗

PubMed2003

Competence of mentally ill patients: a comparative empirical study.

BACKGROUND: This study investigates the competence of patients with dementia, depression and schizophrenia to make treatment decisions. The outcome of an objective test instrument is presented and compared with clinical assessment of competence by the attending physician. METHOD: The MacArthur Competence Assessment Tool-Treatment (MacCAT-T), a test instrument to assess abilities in different standards of competence, was administered to patients with diagnoses of dementia (N = 31), depression (N = 35) and schizophrenia (N = 43). Statistical significance of group differences in the MacCAT-T results were tested with the chi-square test. The concordance of the test and clinical assessment of competence by the attending physician were evaluated by Cohen's kappa coefficient. RESULTS: Patients with dementia, as a group, showed significantly more often impaired performance than those with schizophrenia who were still more impaired than depressed patients. Patients were classified as impaired or not depending on the standards used. By combination of all standards substantially more patients were classified as impaired than by clinical assessment (67.7 v. 48.4% of patients with dementia, 20.0 v. 2.9% of patients with depression, 53.5 v. 18.4% of patients with schizophrenia). CONCLUSIONS: Using different standards of competence the study showed substantial differences among patients with dementia, depression and schizophrenia. The high proportion of patients identified as incompetent raises several ethical questions, in particular, those referring to the selection of standards or the definition of cut-offs for incompetence. The discrepancy between clinical and formal evaluations points out the influence of the used procedure on competence judgements.

Adult↗

PubMed2002

Genetic programming approach for the optimal selection of combinations of neuronal networks to classify sleep stages by QUISI.

The usefulness of a new way to optimize the cooperation of trained neural networks for automatic one-channel sleep stage analysis using genetic programming and performance evaluation by including the interrater reliability are the focus of our paper. The one-channel sleep classification could be significantly improved by the optimization. The software tool HENNE, with its genetic programming compartment was developed for this purpose. The tool has proved to be useful for searching for optima in difficult goal surfaces. To contribute to the general discussion about the benefit of the automatic one-channel sleep analysis on the basis of the frontal site, we tried to evaluate our results before the background of the interrater variability. Comparing the kappa statistics of different independent studies with our results, we concluded that there are no dramatic differences as a rule and that QUISI is a useful device as a presleep laboratory and ambulatory diagnostic tool.

Humans↗

PubMed2001

P300 and symptom improvement in schizophrenia.

RATIONALE: A reduced amplitude of the auditory evoked P300 was interpreted as a trait marker of schizophrenia but reports about correlations between schizophrenic psychopathology and P300 amplitude indicate also a state character. OBJECTIVES: To shed light upon these trait and state aspects a longitudinal study was performed to investigate the influence of symptom improvement and atypical neuroleptics on the amplitudes of the P300 and their subcomponents. METHODS: P300 was recorded in 17 schizophrenic patients before and after 4 weeks under either clozapine or olanzapine in a double-blind controlled design. For comparison, 17 age- and sex-matched healthy subjects were investigated. Parietal and frontal P300 subcomponents were investigated separately using dipole source analysis. RESULTS: Schizophrenic patients had smaller parietal (temporo-basal dipole) but not frontal subcomponent amplitudes (temporo-superior dipole) than controls. For the whole sample subcomponent amplitudes did not change over 4 weeks despite clinical improvement but patients with a pronounced improvement of the PANSS positive score showed a slight enhancement of both subcomponents. This was not significant when the P300 amplitude was measured at a single electrode (Pz). No significant difference between clozapine and olanzapine concerning effects on P300 amplitudes were observed. CONCLUSIONS: The results indicate that P300 subcomponents are modulated by changes of positive but not by changes of negative symptoms or different neuroleptics. This result was obvious for P300 subcomponents but not for Pz electrode measurement, which may be due to a higher reliability of the dipole source activity. The results can be integrated into a hypothetical model containing two pathophysiological subgroups of schizophrenia.

Adult↗

PubMed2001

Body weight and the shape of the natural distribution of weight, in very large samples of German, Austrian and Norwegian conscripts.

OBJECTIVE: To investigate the shape of the natural distribution of body weight in conscripts. DESIGN: Investigation of weight and weight distributions in German, Austrian and Norwegian conscripts. SUBJECTS: A total of 10 706 651 West German conscripts (30 birth cohorts born between 1938 and 1971, except for the cohorts born 1941-1944), 507 095 Austrian conscripts (10 birth cohorts born between 1966 and 1975), and 27 311 Norwegian conscripts (1997 conscription). RESULTS: In Germans, average body weight increased by 100 g/y up to birth cohort 1965, thereafter by 400 g/y, and by 200 g/y in Austrians. Body weight is not normally distributed, but skewed to the right. Also power transformation was inadequate to sufficiently describe the shape of this distribution. The right tail of weight distributions declines exponentially, beyond a cut-off of +0.5 standard deviations. There is a strong relation between average weight and the prevalence of obesity, except for those cohorts that suffered from severe starvation (1945-1948) during early and mid-childhood. These cohorts appeared to be more resistant against obesity. CONCLUSION: Obesity appears to be a characteristic feature of a population as a whole, and does not seem to be a separate problem of only the obese people. It may be questioned whether (in terms of public health) the optimal solution for treating obesity is treating the obese people, or whether one should consider measures to reduce average weight in a population instead, as this might reduce the number obese people and the severity of the illness.

Austria↗

PubMed2001

Time-of-day variations in different measures of sleepiness (MSLT, pupillography, and SSS) and their interrelations.

The aim of the present study is to analyze how well physiological measures of sleepiness derived from pupillography and the Multiple Sleep Latency Test correlate with a subjective measure, the Stanford Sleepiness Scale (SSS) score. The results are based on data from 12 healthy participants, who underwent these tests every 2 hr from 7:00 a.m. until 11:00 p.m. Sleep latencies were correlated with four different variables derived from pupillography and the SSS score. The results indicate that the physiologically based variables correspond very well. This is reflected by similar patterns of time-of-day variations, a good agreement at the group level, and correlations at the individual level, whereas the SSS shows a quite different pattern of variation. The two physiological measures of sleepiness seem to reflect the same aspect of the level of tonic central nervous activation, which is not correlated with the subjective feeling of sleepiness.

Adult↗

PubMed2000

Time-of-day variations of indicators of attention: performance, physiologic parameters, and self-assessment of sleepiness.

BACKGROUND: A study was performed to analyze time-of-day variations of different indicators of attention and their interrelations. METHODS: After a sufficiently long all-night sleep 12 healthy non-sleep-deprived subjects ran through a test battery (Stanford Sleepiness Scale, Visual Analogue Scale, Critical Flicker Fusion Test [CFF], Visualization Test, Number Facility Test, Reaction Time, Pupillometry, and modified Multiple Sleep Latency Test) every 2 hours from 7:00 AM until 11:00 PM. Time-of-day variations were tested nonparametrically with Friedman's test for repeated measurements. Principal component factor analysis (of individually standardized values) was used to identify variable complexes with the same pattern of time-of-day variation. RESULTS: Statistically significant time-of-day variations were found for all variables, except for Fusion Frequency in CFF and Reaction Time. In factor analysis the physiologic parameters (pupillometric variables and sleep latencies) load on one factor, whereas the self-assessment scales, the Visualization Test, Number Faculty Test, and CFF load on the second factor. The variables that load primarily on factor 1 show peak levels of alertness immediately after getting up (at 7:00 AM) and again at 9:00 PM. Those variables that load primarily on factor 2 indicate a peak level of alertness around noon (11:00 AM-3:00 PM). CONCLUSIONS: Different aspects of attention follow different time-of-day variations. It is discussed, that these findings can be attributed to underlying circadian and homeostatic factors.

Adult↗

PubMed2000

[Saarland Growth Study: sampling design].

The use of reference data to evaluate the physical development of children and adolescents is part of the daily routine in the paediatric ambulance. The construction of such reference data is based on the collection of extensive reference data. There are different kinds of reference data: cross sectional references, which are based on data collected from a big representative cross-sectional sample of the population, longitudinal references, which are based on follow-up surveys of usually smaller samples of individuals from birth to maturity, and mixed longitudinal references, which are a combination of longitudinal and cross-sectional reference data. The advantages and disadvantages of the different methods of data collection and the resulting reference data are discussed. The Saarland Growth Study was conducted for several reasons: growth processes are subject to secular changes, there are no specific reference data for children and adolescents from this part of the country and the growth charts in use in the paediatric praxis are possibly not appropriate any more. Therefore, the Saarland Growth Study served two purposes a) to create actual regional reference data and b) to create a database for future studies on secular trends in growth processes of children and adolescents from Saarland. The present contribution focusses on general remarks on the sampling design of (cross-sectional) growth surveys and its inferences for the design of the present study.

Adolescent↗

PubMed2000

[Saarland Growth Study: analyses of body composition of children, aged 3 to 11 years. Measurement of height, weight, girth (abdomen, upper arm, calf) and skinfolds (triceps, biceps, subscapular,suprailiacal, abdominal) and bioelectric impedance (BIA)].

This study aimed to set up current reference charts of anthropometric data in the Saarland. Only national and international data were available to be compared but no former Saarland charts could be found. In the period between 1994 and 1995 we investigated children of 3 to 11 years in a cross-sectional study. Therefore we measured body height, weight, circumferences, skinfolds and bioelectrical impedance (BIA). No significant gender differences were found for body height and weight. Boys of all groups of age showed bigger abdominal circumferences than girls of the same age. On the other hand upper-arm and calf-girth of younger girls were larger than that from boys. In higher age groups circumferences become rather equal. The skinfolds of Saarland girls are thicker than those of boys. The urban rural comparison indicated no significant differences. Nor was any social divergence found among the aforementioned parameters. Regarding height Saarland children are seen to be similar or somewhat shorter than those examined in national or international studies. By the way, in higher percentiles the children in our study were heavier. Thus high BMI values of our study are bigger compared with former studies. According to the definition of obesity by the ECOG almost 20 to 30% of our children are obese. The older children become the higher is the percentage of obesity. Comparing girls and boys, bioelectrical impedance shows higher values for girls. In higher age classes resistance levels gets smaller, in boys more so than in girls. Body fat estimated by a formula based on BIA test parameters yielded negative values. So we propose the use of sex- and age-specific raw charts of BIA test parameters.

Age Distribution↗

PubMed2000

[Saarland Growth Study: percentile charts for height, weight, and body mass index (BMI) for boys and girls, 4-18 years old, in Saarland].

In a cross-sectional study dating from april 94 to march 96 we have investigated length and weight of 2610 girls and 2865 boys (age 4-18 years) at nursery schools and schools in Saarland. Thus we could provide first normative data for this region of Germany. Compared with data that have been collected between 1968 and 1989 at Dortmund, Bonn, Hamm and Jena, we found an increase in height of 2 cm for girls and boys aged 15-18 years. Apart from this finding, no further differences have been observed. Compared with international data, 18-year-old females and males in Saarland show large body heights: their average heights were 169 and 182 cm, respectively. Unfortunately, body weight of children of the Saarland is high, too. Children in Saarland were on average 1.5-6.6 kg heavier than those of the Dortmund study or other international studies. Studies have revealed that, according to the ECOG criteria, people of the Saarland are more obese than in other European countries. As a consequence of our study we request an institution for auxology to be founded which enables immediate reaction. This not only implies medical view points but also practical aspects of daily life (e.g. height of chairs or tables at schools). It is important to note that no changes have been made so far. Standards for height and weight should be updated every ten years. This should be a collaborative task between public health services and pediatric endocrinologists.

Adolescent↗

PubMed1997

GM and KM allotypes in eight tribal populations of Madyha Pradesh and Orissa, India.

Serum samples from eight endogamous Indian tribal populations of Madhya Pradesh (Dhurwa, Halba, Bhatra, Muria, Maria) and Orissa (Deshia Khond, Binjhal, Kisan) with a total of n = 731 unrelated individuals were typed for G1M (1,2,3,17), G3M (5,10,11,13,14,15,16,21, 26), and KM (1). In seven of these populations five different GM haplotypes were found: GM* 1,17;21,26; GM* 1,17;10,11,13,15,16; GM* 1,2, 17;21,26; GM* 1,3;5,10,11,13,14,26; and GM* 3;5,10,11,13,14,26. In the Kisan sample the haplotype GM* 1,2,17;21,26 is absent. The intergroup variability in the distribution of these haplotypes is considerable and statistically highly significant. The reasons for that can be attributed to the ethnohistory and to the genetic isolation of these eight endogamous tribal populations. The GM haplotype distribution pattern of all these groups is quite different from that of the non-tribal populations of India, whereas it is in good agreement with that of the so far tested other tribal populations from India. This can be explained by different origin and history of the Indian tribal and non-tribal populations. In the KM system, too, remarkable variability is seen in the distribution of phenotype and allele frequencies among the eight tribal populations under study.

Ethnicity↗

PubMed1996

Association between the PI*M3 allele of alpha 1-antitrypsin and Alzheimer's disease? A preliminary report.

The deposition of beta A4-amyloid in senile plaques in the brain and small cerebral vessels is one of the pathological hallmarks of Alzheimer's disease (AD). Serine protease inhibitors (serpins) such as alpha 1-antitrypsin and alpha 1-antichymotrypsin have been found to be associated with beta-amyloid deposits; interest in their role in the pathogenesis of AD has therefore recently increased. We have analyzed alpha 1-antitrypsin phenotypes in a sample of 29 Polish patients with probable Alzheimer's disease. We have found an increased frequency of the PI*M3 allele (0.1897) in patients in comparison with the general population control (0.0563).

Adult↗

PubMed1995

Regulation of food intake during the menstrual cycle.

Several studies indicate that food intake and selection varies during menstrual cycle. The present results are based on nutritional diaries kept by 27 healthy regularly menstruating women, who did not use oral contraceptives. Over a time period of at least one menstrual cycle the women recorded their daily ad libitum food intake by specifying the different nutrients and the respective amounts. The daily total energy, carbohydrate, protein and fat intake was analyzed using the national foodstuff code provided by the National Health Institute with regard to different phases of the menstrual cycle. The latter were controlled by daily measurements of basal temperature. The results indicate that during the luteal phase of menstrual cycle the intake of total energy tends to be higher than during follicular phase. Carbohydrate intake was on the lowest point during periovulatory period reaching a minimum approximately 2 days after ovulation. Such a minimum could also be observed in fat and total energy intake. Furthermore it could be demonstrated that the subjective perception of "sweetness" varied with cycle phases. The results suggest that food intake and selection is influenced by neurochemical, hormonal, physiological and psychological factors.

Adult↗

PubMed1995

Serum protein polymorphisms in seven populations from Middle Eastern and Eastern Europe.

Serum specimens from 1385 unrelated males and females from seven Middle East and East European sample surveys (Prague, Olomouc, Krakow, Poznan, Szeged, Moscow, and Jekaterinburg) have been typed for seven polymorphic serum protein polymorphisms (GC, TF, PLG, PI, A2HS, F13B, and ITI). The distributions of phenotype and allele frequencies show a marked heterogeneity, especially with regard to the allel GC*1F of the GC system, the alleles A2HS*1 and A2HS*2 of the A2HS system and the alleles F13B*1 and F13B*3 allele of the F13B system. Analysis of the genetic variability by means of distance and principal component analysis revealed that with regard to the seven polymorphic loci studied the population samples from Prague and Jekaterinburg are characterized by deviating genetic structures. While the different genetic structure of the sample from Prague is mainly due to the distribution of the alleles at the A2HS locus, the sample from Jekaterinburg shows differences in several loci. The genetic dissimilarity corresponds to the large geographic distance from the other populations and can presumably be explained with the comparatively heterogeneous ethnic composition of the population of this city located at the geographic borderline between Europe and Asia.

Alleles↗

PubMed1993

Genetic serum protein markers in eight south Indian caste and tribal populations.

A total of n = 769 unrelated male and female individuals from eight endogamous caste (Brahmin, Kapu, Yadava, Relli) and tribal (Bagatha, Kotia, Manne Dora, Konda Dora) populations living in various districts of Andhra Pradesh (India) have been typed for haptoglobin (HP) types and transferrin (TF), group specific component (GC) and alpha 1-antitrypsin (PI) subtypes. The genetic heterogeneity among these population groups is considerable. This can be explained by lacking or at least only minimal gene flow among these caste and tribal groups, by which differences in their genetic profiles caused by locally acting genetic differentiation factors such as drift could be preserved.

Alleles↗

PubMed1992

Investigations on the variability of blood group polymorphisms among sixteen tribal populations from Orissa, Madhya Pradesh and Maharashtra, India.

Sixteen tribal populations from Orissa, Madhya Pradesh and Maharashtra have been typed for the polymorphic blood group systems A1A2B0, MNSs, Rhesus, Kell, Duffy and Diego. The heterogeneity in the distribution of haplotype and allele frequencies, respectively, is partly considerable. It is supposed that this is due to the operation of several microevolutionary factors, such as genetic drift, social and geographic isolation and gene flow. This is discussed in detail.

Alleles↗