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Biomedical subjects

M Schulz

Publications and source records attributed to M Schulz.

At least 19 recordsLinked to original sources
PubMed2001

Variations of the asset prices.

The empirical established non-Gaussian behavior of asset price fluctuations is studied using an analytical approach. The analysis is based on a nonlinear Fokker-Planck equation with a self-organized feedback-coupling term, devised as a fundamental model for price dynamics. The evidence, and the analytical form of the memory term, are discussed in the context of statistical physics. It will be suggested that the memory term in leading order offers a power law dependence with an exponent straight theta. The stationary solution of the probability density leads asymptotically to a truncated Lévy distribution, the characteristic exponent beta of which is related to the exponent straight theta by beta=3/theta-1. The empirical data can be reproduced by theta approximately 5/4.

Journal Article↗
PubMed2001

Timbre-specific enhancement of auditory cortical representations in musicians.

Neural imaging studies have shown that the brains of skilled musicians respond differently to musical stimuli than do the brains of non-musicians, particularly for musicians who commenced practice at an early age. Whether brain attributes related to musical skill are attributable to musical practice or are hereditary traits that influence the decision to train musically is a subject of controversy, owing to its pedagogic implications. Here we report that auditory cortical representations measured neuromagnetically for tones of different timbre (violin and trumpet) are enhanced compared to sine tones in violinists and trumpeters, preferentially for timbres of the instrument of training. Timbre specificity is predicted by a principle of use-dependent plasticity and imposes new requirements on nativistic accounts of brain attributes associated with musical skill.

Acoustic Stimulation↗
PubMed2001

Identification of nucleolin as a glucocorticoid receptor interacting protein.

The glucocorticoid receptor (GR) is a ligand-induced transcription factor which modulates the transcriptional activity of target genes. Full transcriptional activity of GR is achieved with the help of accessory proteins that are able to interact with GR. We have identified a 95-kDa protein by a blotting technique which utilizes a radioactively labeled DNA-bound GR to detect proteins that bind to this complex. Biochemical purification of this protein followed by protein microsequencing resulted in the identification of human nucleolin. In addition we could show that a GR-deletion mutant localizes to the nucleolus, where nucleolin is one of the most abundant proteins. The binding of nucleolin to this deletion mutant was demonstrated by GST-pull-down experiments. We suggest a biological role of nucleolin in binding of GR in the nucleolus.

Animals↗
PubMed2001

Seasonal dependence of the chiral composition of alpha-HCH in coastal deposition at the North Sea.

The environmental pollutant alpha-HCH was analysed in seawater, air and bulk deposition samples from the North Sea. Enantioselective analyses of the sample extracts gave evidence of the change of the direction of net air-water gas transfer of the contaminant in dependence on the season. Due to warmer water surface temperatures during late summer to early autumn the equilibrium of alpha-HCH between air and water is dominated rather by volatilisation than deposition. The volatilisation of non-racemic alpha-HCH, as known to occur from seawater, changes the enantiomeric ratio in air, which is reflected in the observed ratio in rain that passes the air column.

Hexachlorocyclohexane↗
PubMed2001

Effects of the heterogeneous nuclear ribonucleoprotein U (hnRNP U/SAF-A) on glucocorticoid-dependent transcription in vivo.

The glucocorticoid receptor (GR) is a ligand dependent transcription factor, which regulates the transcription of multiple hormone-dependent genes. The transcriptional regulation by GR takes place by interaction of GR with the basal transcription machinery and by recruiting glucocorticoid receptor interacting proteins (GRIPs). Previously we identified hnRNP U/SAF-A as a factor interfering with GR-dependent transcription by repressing glucocorticoid induced activation. To gain insight into the mechanisms that govern this interference, we have now investigated the transcription of GR-dependent reporter genes in Ltk(-) cells transiently transfected with a variety of hnRNP U constructs. We demonstrate that a hnRNP U construct lacking the GR-binding domain acts as a dominant negative factor that now enhances GR-driven transcription. In addition, hnRNP U repression of glucocorticoid induced transcription was found to be dependent on the amount of cotransfected GR, where a high amount of GR leads to ligand-inducible repression of GR-dependent reporter gene activity by hnRNP U, whereas low amounts of GR showed nearly no effect. The relative concentrations of GR, hnRNP U and DNA-binding sites for GR are important for the effect of hnRNP U on transcription, suggesting a model where hnRNP-U acts as a storage site for intranuclear GR.

Binding Sites↗
PubMed2001

Dysfunction of transcallosally mediated motor inhibition and callosal morphology in patients with schizophrenia.

OBJECTIVE: In order to assess the functional integrity of motor pathways through the corpus callosum (CC) in patients with schizophrenia transcallosally mediated inhibition (TI) of voluntary tonic EMG activity of first dorsal interosseus muscle following ipsilateral focal transcranial magnetic stimulation (fTMS) was investigated. In addition thickness and length of CC were calculated. METHOD: Twelve patients suffering from schizophrenia and 12 healthy controls were investigated. CC morphology was measured in mid-sagittal MRI-slices. Latency and duration of TI were calculated. RESULTS: In schizophrenics the duration of TI was significantly prolonged, whereas latencies were not. In addition, a lack of TI was found unilaterally in three patients. Measurements of CC revealed a significantly reduction of the length and thickness in the anterior part of CC in patients. CONCLUSION: These findings indicate that measurement of TI could be used to detect clinical silent affection of transcallosal motor pathways in schizophrenics. The effect of neuroleptic drugs has to be explored.

Adult↗
PubMed2001

Pharmaceutical care services for asthma patients: a controlled intervention study.

As asthma is associated with an enormous social, psychological, and economic burden, various patient education programs have been developed to improve outcomes, including quality of life. The authors evaluated the effectiveness of community pharmacy-based interventions on lung function, health-related quality of life, and self-management in asthma patients in a 12-month controlled intervention study in 26 intervention and 22 control pharmacies. Pharmacies opted whether to take part as intervention or control pharmacies. According to this, patients (ages 18-65) with mild to severe asthma attending the pharmacies were allocated to the intervention (n = 161) or control group (n = 81), respectively. Intervention patients were educated on their disease, pharmacotherapy, and self-management; inhalation technique was assessed and, if necessary, corrected. Pharmaceutical care led to significantly improved inhalation technique. Asthma-specific quality of life and the mental health summary score of the SF-36 improved significantly in the intervention group. At 12 months, the intervention group showed significant improvements with regard to evening peak flow, self-efficacy, and knowledge.

Administration, Inhalation↗
PubMed2001

Lack of methemoglobinemia with flutamide.

OBJECTIVE: To determine whether the nonsteroidal antiandrogenic drug flutamide is a clinically relevant inducer of methemoglobinemia in patients with prostatic cancer. METHODS: Fifty consecutive outpatients with prostatic cancer stage D2 entered the study (age 71.1 +/- 7.3 y). Five patients were lost to follow-up; the remaining 45 patients received the recommended oral dose of flutamide 250 mg three times daily. Total hemoglobin (Hb) and methemoglobin (Met-Hb) concentrations were measured on varying days using an ultraviolet/visible-spectrophotometric method with an intra- and interday variability < 8%. In 12 patients, Met-Hb was analyzed before initiating flutamide therapy and after therapy was begun. RESULTS: On average, 2.6 venous blood samples per patient were analyzed with a mean Met-Hb concentration of 1.9% of total Hb. Mean concentrations of > or = 3% were detected in only six patients (13%). The data from 12 patients evaluated before and after initiating flutamide therapy were without significantly different changes. During the study period, no clinical signs of methemoglobinemia were reported or observed. CONCLUSIONS: This study found no clinically relevant increase of Met-Hb concentrations in elderly patients with prostatic cancer during chronic treatment with flutamide. However, clinicians should be aware of the very rare possibility of flutamide-induced methemoglobinemia.

Aged↗
PubMed2000

Fatal intoxication with melperone.

Melperone is judged to be a safe neuroleptic drug. Until now there has been no report of a melperone fatality, though it has been used in suicide attempts. We report on a case of a 36-year-old woman where no cause of death could be established at autopsy. Criminological investigation pointed to a homicide by poisoning but also the possibility of a suicide had to be taken in account. The toxicological analysis of blood, cerebral spinal fluid and urine revealed extremely high concentrations of melperone which had never been reported before. Furthermore, diazepam, nordazepam and carbamazepine were detected. To our knowledge, this case is the first melperone fatality. Possible interactions with diazepam and carbamazepine are discussed.

Adult↗
PubMed2000

Electron correlations observed through intensity interferometry

Intensity interferometry was applied to study electron correlations in doubly ionizing ion-atom collisions. In this method, the probability to find two electrons emitted in the same double ionization event with a certain momentum difference is compared to the corresponding probability for two uncorrelated electrons from two independent events. The ratio of both probabilities, the so-called correlation function, is found to sensitively reveal electron correlation effects, but it is rather insensitive to the collision dynamics.

Journal Article↗
PubMed2000

Mortality from six work-related cancers among African Americans and Latinos.

BACKGROUND: Ethnic minorities have been omitted from many occupational health studies, despite their substantial contributions to the labor force and documented cases of high exposures in some settings. To describe the occurrence of potentially work-related cancers among African American and Latino Workers, we conducted an epidemiologic study based on death certificate data. METHODS: Data were obtained from 21 states during 1985-1992. Directly adjusted proportionate mortality ratios (PMRs) and standardized mortality rate ratios (SRRs) for ages 20-64 years were computed for cancers of the lung, nasal cavity, pleura, and peritoneum, malignant melanoma and leukemia using the mortality data and population counts from the 1990 census. RESULTS: Proportionate mortality was generally low for both groups, but African Americans had higher than expected mortality rates for leukemia and cancers of the lung, nasal cavity, and peritoneum. Industry-specific analyses indicate excess leukemia among African American men in the rubber industry (PMR 2.08, 95% confidence interval (CI) 1.29 - 3.35), Latino men in textile (PMR 2. 31, 95% CI 0.81 - 5.13) and wood industries (PMR 2.03, 95% CI 0.81 - 5.13), and Latino women in the chemical industry (PMR 2.18, 95% CI 0.59 - 8.10), among other findings. Excess cancer of the pleura and peritoneum was observed among workers with a variety of usual occupations, consistent with widespread exposure to asbestos. CONCLUSIONS: This study demonstrates the utility of surveillance data bases for generating basic epidemiologic information on historically neglected workers. Leads about specific workplace exposure can be followed up in more detailed studies.

Adult↗
PubMed2000

Coherent membrane supports for parallel microsynthesis and screening of bioactive peptides.

Since its invention the SPOT-synthesis methodology has become one of the most efficient strategies for the miniaturized assembly of large numbers of peptides. The combination of a facile synthetic method with high throughput solid- and solution-phase screening assays qualifies the SPOT-technique as a valuable tool in biomedical research. Recent developments such as the introduction of novel polymeric surfaces, new linker and cleavage strategies as well as automated robot systems extended the scope of practical chemical reactions that can be accommodated as well as the numbers of compounds obtainable by this technique. Thus, highly complex spatially addressed compound arrays have become accessible. Together with the introduction of novel screening assays, the method is excellently suited to elucidate recognition events on the molecular level.

Adsorption↗
PubMed2000

Formation and degradation of a synthetic humic acid derived from 3-fluorocatechol.

A synthetic fluorinated humic acid (FHA) was prepared by the spontaneous oxidative polymerization of 3-fluorocatechol. The 13C-solid-state NMR spectrum showed signals in the region for aromatic carbons with different substituents (aryl-H, aryl-C, aryl-O carbons) and for carboxyl-carbon. The latter indicated the formation of carboxylic groups, probably caused by ring cleavages during the polymerization process. An indication of the formation of carboxylic groups was also found in the infrared spectrum (band at 1715 cm(-1)). The dissolved FHA was degraded with active mycelium of the agaric white-rot fungus Nematoloma frowardii as well as with its isolated manganese peroxidase. In both cases, decolorization of the brownish FHA solution and partial defluorination (45-60%) took place. Degradation proceeded via formation of lower-molecular-mass fulvic acid-like substances. The results demonstrate that halogenated humic substances, e.g., resulting from the humification of xenobiotic compounds (bound residues), can in principle be eliminated by ligninolytic fungi (e.g., soil colonizing litter decomposers) and their manganese peroxidase system.

Agaricales↗
PubMed2000

Distinct proteins interacting with the glucocorticoid receptor.

The glucocorticoid receptor (GR) is a hormone-dependent transcription factor that modulates gene transcription by binding to its response element, interacting with other transcription factors, contacting the basal transcription machinery and by interacting with several intermediary proteins, such as coactivators. Here we discuss the most prominent examples for interacting transcription factors, interacting proteins that belong to the basal transcription apparatus and intermediary factors. Furthermore, we describe a new class of GR-interacting proteins (GRIPs) which have been identified by a blotting technique, using a radioactively labeled GR/GRE complex as a probe to identify proteins that interact with the activated GR. Two of these GRIPs, termed GRIP170 and GRIP 120, which were identified by biochemical purification and microsequencing and have turned out to play a role in modulating GR-mediated transcription, are discussed in detail.

Animals↗
PubMed2000

Riboflavin deficiency and preeclampsia.

OBJECTIVE: To examine in a prospective study riboflavin deficiency as a predisposing factor for preeclampsia in a high-risk collective of pregnant women in Zimbabwe. METHODS: At an antenatal clinic in Bulawayo, Zimbabwe, 154 women at increased risk for preeclampsia were observed prospectively until delivery. Riboflavin status was determined using the erythrocyte glutathione reductase activation coefficient test on the day of antenatal booking. Riboflavin deficiency was expressed by erythrocyte glutathione reductase activation coefficient of 1.4 or greater. RESULTS: Riboflavin deficiency was frequently found among the study population (33.8%). Incidence rose toward the end of pregnancy (27.3% at 29-36 weeks' gestation compared with 53.3% at over 36 weeks). In the riboflavin-deficient group, mothers were more likely to develop preeclampsia (28.8%) than in the riboflavin-adequate group (7.8%; P <.001, odds ratio [OR] 4.7, 95% confidence interval [CI] 1.8-12.2). The calculated concentrations of intracellular free flavin adenine dinucleotide were significantly lower in patients who developed preeclampsia than in normal pregnancies (P <.05). CONCLUSION: Riboflavin deficiency should be considered a possible risk factor for preeclampsia. Insufficient concentrations of the riboflavin-derived cofactors flavin adenine dinucleotide and flavin adenine mononucleotide could contribute to the established pathophysiologic changes including mitochondrial dysfunction, enhanced oxidative stress, and disturbances in nitric oxide release.

Adult↗
PubMed2000

Role of natural benzoxazinones in the survival strategy of plants.

Benzoxazinoid acetal glucosides are a unique class of natural products abundant in Gramineae, including the major agricultural crops maize, wheat, and rye. These secondary metabolites are also found in several dicotyledonous species. Benzoxazinoids serve as important factors of host plant resistance against microbial diseases and insects and as allelochemicals and endogenous ligands. Interdisciplinary investigations by biologists, biochemists, and chemists are stimulated by the intention to make agricultural use of the benzoxazinones as natural pesticides. These natural products are not only constituents of a plant defense system but also part of an active allelochemical system used in the competition with other plants. This review covers biological and chemical aspects of benzoxazinone research over the last decade with special emphasis on recent advances in the elucidation of the biosynthetic pathway.

Animals↗