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B Schneider

Publications and source records attributed to B Schneider.

At least 73 records · Page 4Linked to original sources
PubMed2002

[Effects of active and passive movement stimuli on cerebral hemodynamics and the cerebral metabolism].

INTRODUCTION: In contrast to the well-examined cardiovascular changes during movement stimuli, up to now changes of cerebral hemodynamics and cerebral metabolism have rarely been studied. We investigated the question if active and passive movement stimuli cause changes in the cerebral hemodynamics and the cerebral metabolism. METHOD: Active and passive repetitive movement stimuli on 14 volunteers (8 females, 6 males, age 35 +/- 8 years) were examined. As a parameter of cerebral hemodynamics the mean and the peak blood flow velocity (mCBFV(MCA), pCBFV(MCA)) in the middle cerebral artery (MCA) were recorded by transcranial Doppler sonography. At the same time the noninvasive blood pressure (Penaz method) and the CO(2) expiration concentration were investigated on 8 volunteers of the collective. As cerebral metabolic parameters we examined in 4 volunteers additionally the cerebral respiratory chain enzyme cytochrome aa3 (ccytaa3) and the cerebral oxygen saturation (cHbO(2)) by the transcranial near infrared spectroscopy. With each volunteer 4 measurement series were carried out with a special active and passive exercise program for the right upper as well as the right lower extremity. Each measurement series was formed according to the evoked flow test (R. Aaslid): Exercises were carried out for 20 s, followed by a break of 20 s; this was repeated 10 times for each series. RESULTS: During active exercises of the right lower extremity we found an increase of 13.6% (p < 0.001) of pCBFV(MCA) and an increase of 3.8% (p = 0.003) of mCBFV(MCA). During passive exercises of the lower extremity the increases ran up to 12.3% (p < 0.001) for pCBFV(MCA) and 3.4% (p = 0.004) for mCBFV(MCA). The increases of pCBFV(MCA) came up to 12.5% (p < 0.001) at active exercises of the right upper extremity, those of mCBFV(MCA) to 3.5% (p = 0.15). During passive exercises of the upper extremity the pCBFV(MCA) increased by 12.2% (p < 0.001) and the mCBFV(MCA) by 4.6% (p = 0.007). Significant increases of ccytaa3 were measured during active exercises of the upper extremity (1.6%; p = 0.04) and of the lower extremity (2.7%, p = 0.007). We also found an increase of ccytaa3 during passive exercises of the upper extremity (1.5%, p = 0.04). Significant changes of cHbO(2) were measured with 2.5% (p < 0.05) at active exercises of the lower extremity. CONCLUSION: These studies show that active as well as passive clinical exercises cause an increase of cerebral blood flow velocity. We attribute the increase of cerebral hemodynamics and cerebral metabolism to cerebral activation and autoregulative mechanisms.

Adult↗
PubMed2001

Clozapine-associated diabetes.

Clozapine is a potent antipsychotic agent that has been marketed since 1990. Several published reports of diabetes mellitus occurring with clozapine therapy have appeared during the past 5 years. Because the risk and characteristics of clozapine-associated diabetes mellitus remain unclear, we conducted a descriptive epidemiologic study of spontaneous adverse event reports of hyperglycemia occurring in clozapine-treated patients. The Food and Drug Administration MedWatch surveillance program was queried (January 1990 through February 2001), and the results were pooled with published cases. Parameters assessed included documentation of diabetes, clinical severity, new-onset diabetes versus exacerbation of preexisting disease, demographic characteristics of patients, time to onset of hyperglycemia, and effect of drug discontinuation and rechallenge. We identified 384 reports. Of these, new-onset diabetes was diagnosed definitively in 242 patients, and 54 patients had exacerbation of preexisting disease. The mean (+/- SD) age was 40 +/- 12 years (range, 13 to 77). The male:female ratio was 2:0. Most cases appeared within 6 months of initiating clozapine therapy. One patient developed diabetes following a single 500-mg dose. There were 80 cases of metabolic acidosis or ketosis. Twenty-five patients died during hyperglycemic episodes. Forty-six patients had improved glycemic control after discontinuation or dose reduction of the drug.A causal relationship between clozapine and diabetes is suggested by the number of reports, the temporal relation to clozapine initiation, the relatively young age of the affected patients, and the prompt reversibility on withdrawal of the drug in some patients. The severity of reported cases ranged from mild glucose intolerance to diabetic ketoacidosis or hyperosmolar coma.

Adolescent↗
PubMed2001

Insulin-like growth factor-I is necessary for neural stem cell proliferation and demonstrates distinct actions of epidermal growth factor and fibroblast growth factor-2.

Neural stem cells (NSCs), when stimulated with epidermal growth factor (EGF) or fibroblast growth factor-2 (FGF-2), have the capacity to renew, expand, and produce precursors for neurons, astrocytes, and oligodendrocytes. We postulated that the early appearance of insulin-like growth factor (IGF-I) receptors during mouse striatum development implies a role in NSC regulation. Thus, we tested in vitro the action of IGF-I on the proliferation of striatal NSCs. In the absence of IGF-I, neither EGF nor FGF-2 was able to induce the proliferation of E14 mouse striatal cells. However, addition of IGF-I generated large proliferative clusters, termed spheres, in a dose-dependent manner. The newly generated spheres were multipotent, and clonal analysis revealed that EGF or FGF-2, in the presence of IGF-I, acted directly on NSCs. The actions of IGF-I suggest distinct modes of action of EGF or FGF-2 on NSCs. First, continuous versus delayed administration of these neurotrophic factors showed that neither IGF-I nor EGF had an effect on NSC survival, whereas FGF-2 promoted the survival or maintenance of the stem cell state of 50% of NSCs for 6 d. Second, short-term exposure to IGF-I induced the proliferation of NSCs in the presence of EGF, but not of FGF-2, through an autocrine secretion of IGF-I. These findings suggest that IGF-I is a key factor in the regulation of NSC activation and that EGF and FGF-2 control striatal NSC proliferation, in part, through distinct intracellular mechanisms.

Animals↗
PubMed2001

Drug-related emergencies and drug-related deaths in Vienna, 1995-1997.

The demographics of drug-related emergencies and drug-related deaths that occurred in Vienna between January 1st, 1995 and December 31st, 1997 were compared to investigate whether they represent two different subgroups of the drug-taking community. Analysis indicated that drug-related emergencies were significantly younger and that the proportion of females was higher than amongst the fatalities. In addition, emergencies were more likely than fatalities to occur in private residences than public places. No significant association between the number of contacts with the Vienna Ambulance Service and the fatal outcome of drug use could be substantiated. The results of this study indicate that drug-related emergencies and drug-related deaths represent two different subpopulations of the drug-taking community. Therefore, different strategies of prevention are considered.

Accidents, Home↗
PubMed2001

Chemical rescue of phosphoryl transfer in a cavity mutant: a cautionary tale for site-directed mutagenesis.

We have explored the ability of a nucleoside diphosphate kinase (NDPK) mutant in which the nucleophilic histidine has been replaced by glycine (H122G) to transfer phosphate from ATP to alcohols of varying pK(a), size, shape, and polarity. This cavity mutant does indeed act as a primitive alcohol kinase. The rate of its phosphoryl transfer to alcohols varies considerably, with values spanning a DeltaDeltaG(double dagger) range of 4 kcal/mol, whereas the alcohols have very similar intrinsic reactivities. Analysis of these results suggests that the ability to carry out phosphoryl transfer within the cavity is not a simple function of being small enough to enter the cavity, but rather is a complex function of steric, solvation, entropic, van der Waals packing, and electrostatic properties of the alcohol. In addition, large differences are observed between the reactivities of alcohols within the nucleophile cavity of H122G and the reactivities of the same alcohols within the nucleophile cavity of H122A, a mutant NDPK that differs from H122G by a single methyl group within the cavity. The crystal structures of the two cavity mutants are very similar to one another and to wild-type NDPK, providing no evidence for a structurally perturbed active site. The differences in reactivity between the two mutant proteins illustrate a fundamental limitation of energetic analysis from site-directed mutagenesis: although removal of a side chain is generally considered to be a conservative change, the energetic effects of any given mutation are inextricably linked to the molecular properties of the created cavity and the surrounding protein environment.

Adenosine Triphosphate↗
PubMed2001

Serum calcium in thyroid disease.

Thyroid hormones are believed to influence calcium metabolism. In the present prospective study we investigated the influence of various thryroid diseases on serum calcium levels. In addition to screening for thyroid diseases we measured serum calcium concentrations (S-Ca) in individuals who came to our outpatient service for thyroid diseases from 1992 to 1998. 13,387 persons, among them 9017 patients with thyroid diseases and 4370 persons without thyroid dysfunction, were studied. S-Ca was found to be higher in patients with hyperthyroidism (2.36 +/- 0.11 mmol/L n = 1201, p < 0.05) than in those with subclinical hyperthyroidism (2.33 +/- 0.11 mmol/L, n = 494), with euthyroid goiter (2.32 +/- 0.10 mmol/l, n = 5599), with hypothyroidism (2.31 +/- 0.11 mmol/L, 344), with subclinical hypothyroidism (2.32 +/- 0.10 mmol/L, n = 1290) and in healthy persons (2.31 +/- 0.11 mmol/L, n = 4370). 173/13,387 persons had serum calcium levels < 2.1 mmol/L, among them 31 patients with hypoparathyroidism after strumectomy (31/592) and 2 patients with primary hypoparathyroidism. 106/13,387 persons showed a S-Ca of > 2.6 mmol/L, which in 30 cases was due to primary hyperparathyroidism. Of 55 persons with S-Ca of > 2.6 mmol/L and without any other reason for hypercalcaemia, 31 were found to be in a hyperthyroid state. In conclusion, a clinically not relevant influence on S-Ca was demonstrated in patients with hyperthyroidism as compared with other thyroid diseases and individuals with no thyroid diseases. Measurement of S-Ca in every patient being referred to a thyroid outpatient department is recommended because of the frequent occurrence of postoperative hypoparathyroidism and primary hyperparathyroidism in this setting.

Adolescent↗
PubMed2001

Accumulation of soluble and wall-bound indolic metabolites in Arabidopsis thaliana leaves infected with virulent or avirulent Pseudomonas syringae pathovar tomato strains.

The chemical structures and accumulation kinetics of several major soluble as well as wall-bound, alkali-hydrolyzable compounds induced upon infection of Arabidopsis thaliana leaves with Pseudomonas syringae pathovar tomato were established. All identified accumulating products were structurally related to tryptophan. Most prominent among the soluble substances were tryptophan, beta-d-glucopyranosyl indole-3-carboxylic acid, 6-hydroxyindole-3-carboxylic acid 6-O-beta-d-glucopyranoside, and the indolic phytoalexin camalexin. The single major accumulating wall component detectable under these conditions was indole-3-carboxylic acid. All of these compounds increased more rapidly, and camalexin as well as indole-3-carboxylic acid reached much higher levels, in the incompatible than in the compatible P. syringae/A. thaliana interaction. The only three prominent phenylpropanoid derivatives present in the soluble extract behaved differently. Two kaempferol glycosides remained largely unaffected, and sinapoyl malate decreased strongly upon bacterial infection with a time course inversely correlated with that of the accumulating tryptophan-related products. The accumulation patterns of both soluble and wall-bound compounds, as well as the disease resistance phenotypes, were essentially the same for infected wild-type and tt4 (no kaempferol glycosides) or fah1 (no sinapoyl malate) mutant plants. Largely different product combinations accumulated in wounded or senescing A. thaliana leaves. It seems unlikely that any one of the infection-induced compounds identified so far has a decisive role in the resistance response to P. syringae.

Arabidopsis↗
PubMed2001

The PDB data uniformity project.

The Protein Data Bank (PDB; http://www.rcsb.org/pdb/) is the single worldwide archive of structural data of biological macromolecules. This paper describes the data uniformity project that is underway to address the inconsistency in PDB data.

Databases, Factual↗
PubMed2001

Microcirculation is similar in ischemic and venous ulcers.

Microcirculation of 15 ischemic and 15 venous ulcers, their scars, and intact surrounding skin were examined in order to demonstrate their similarities in the development and healing process. Subpapillary and nutritive perfusion of four areas were investigated by a laser Doppler perfusion imager (arbitrary units) and capillary microscopy (capillaries/mm2): one ulcer area without granulation tissue (no wound healing) and one with granulation tissue (ulcer healing); one skin area adjacent to the ulcer (1-8 mm) (scar developed from ulcer areas) and one distant (12-25 mm; intact skin). Areas without granulation tissue in ischemic and venous ulcers were similar, demonstrating a lack of capillaries (0.13 +/- 0.52; 0.93 +/- 2.09) and low laser Doppler flux (0.81 +/- 0.69; 1.47 +/- 1.17; P > 0.05 for each). In granulation tissue of both ulcers there was a tendency to a higher capillary density (0.67 +/- 1.40; 5.60 +/- 2.32; P < 0.0001 for venous ulcers) and a higher laser Doppler flux (1.15 +/- 0.67; 4.04 +/- 1.62; P < 0.0001 for venous ulcers) than in areas without granulation tissue. In scars of ischemic and venous ulcers capillary density (8.18 +/- 8.84; 13.60 +/- 5.45) and laser Doppler flux (1.72 +/- 1.00; 1.94 +/- 1.45) were similar (P > 0.05). In skin distant from ischemic ulcers very high capillary density (24.63 +/- 1.89) was associated with low laser Doppler flux (0.99 +/- 0.59); distant from venous ulcer capillary density was moderate (10.47 +/- 3.42) while laser Doppler flux was high (3.77 +/- 1.62; P < 0.0001 between both groups). The development and healing process of ischemic and venous ulcers is similar. Nutritive and subpapillary perfusion are involved in ulcer healing. In intact skin surrounding ischemic and venous ulcers, microcirculation is different due to the underlying pathophysiology.

Aged↗
PubMed2001

[Ductus arteriosus apertus as the cause of recurrent nerve paralysis. A case report].

There are various reasons for paralysis of the vocal folds, which consequently imposes great demands on differential diagnostics. Angiocardiopathies are regarded as very rare cases of etiopathogenesis. In the present case, a persistent arterial duct could be identified as the reason for the paralysis of the left recurrent nerve of a 59-year-old female patient. The necessity of interdisciplinary diagnostics going beyond the field of otorhinolaryngology is emphasized, especially in cases of a paralysis of the recurrent nerve.

Diagnosis, Differential↗
PubMed2001

Increased plasma leptin in gestational diabetes.

AIMS/HYPOTHESIS: Insulin resistance as well as marked changes in body weight and energy metabolism are associated with pregnancy. Its impact on plasma leptin is not known and was determined in this longitudinal study in both diabetic and normal pregnancy. METHODS: At 28 gestational weeks plasma concentrations of leptin and B-cell hormones were measured at fasting and after an oral glucose load (OGTT:75 g) in women with gestational diabetes and pregnant women with normal glucose tolerance and compared with women who were not pregnant (C). RESULTS: Plasma leptin (ng/ml) was higher (p < 0.001) in women with gestational diabetes (24.9 +/- 1.6) than in women with normal glucose tolerance (18.2 +/- 1.5) and increased in both groups when compared with the non-pregnant women (8.2 +/- 1.3; p < 0.0005). No change in plasma leptin concentrations was induced by OGTT in any group. Basal insulin release was higher (p < 0.05) in women with gestational diabetes compared with the pregnant women with normal glucose tolerance. Marked insulin resistance was confirmed by a 20 % lower (p < 0.05) insulin sensitivity in subgroup analysis and a decrease of almost 40% in fasting glucose/insulin ratio (p < 0.005) in women with gestational diabetes. Leptin correlated in women with gestational diabetes with basal plasma concentrations of glucose (p < 0.02), insulin (p < 0.004) and proinsulin (p < 0.01) as well as with BMI (p < 0.001) and overall pregnancy induced maternal weight gain (p < 0.009). With normalisation of blood glucose 8 weeks after delivery in women with gestational diabetes their plasma leptin decreased (p < 0.0005) to 17.3 +/- 1.9 ng/ml but did not completely normalize (p < 0.05 vs non-pregnant women). CONCLUSION/INTERPRETATION: Our data show that women with gestational diabetes without any change in plasma leptin upon oral glucose loading have increased plasma leptin concentrations during and after pregnancy, a clear association of plasma leptin with the respective concentration of glucose and insulin resistance as well as with changes in body weight, and a failure to normalize spontaneously BMI to the same extent as pregnant women with normal glucose tolerance when compared with matched control subjects.

Adult↗
PubMed2001

Impact of complementary oral enzyme application on the postoperative treatment results of breast cancer patients--results of an epidemiological multicentre retrolective cohort study.

PURPOSE: [corrected] To evaluate the impact of postoperative treatment with an oral enzyme (OE) preparation given complementary to an antineoplastic therapy in patients with breast cancer. METHODS: The design of this epidemiological study was a retrolective cohort analysis with parallel groups. Design and conduct of the study were performed to current standards for prospective, controlled clinical trials. A cohort of 2,339 breast cancer patients undergoing surgical intervention and radio-, chemo- or hormonal therapy were studied in 216 centres. Of the 2,339 patients, 1,283 received complementary treatment with OE and 1,056 did not receive OE. Patients with other complementary medications were excluded and the final analysis was performed with the data from 649 patients, of whom 239 (37%) were additionally treated with OE (test group) and 410 (63%) without OE (control group). The median follow-up time for the test group was 485 days and for the control group 213 days. The primary endpoint of the study was to determine whether complementary treatment with OE can reduce typical disease- or therapy-associated signs and symptoms (gastrointestinal symptoms, mental symptoms, dyspnoea, headache, tumour pain, cachexia, skin disorders, infections, and side effects associated with the antineoplastic therapy) in patients with breast cancer. Imbalances for causal effects (covariates) were adjusted for by means of the propensity score. Outcome analysis was performed by estimating the linear regression between change in symptom score and propensity score with all data and using this regression line to calculate the change in symptom score which would be expected for each patient. Tumour-associated events (recurrence, metastasis, and death) were evaluated in terms of the number of events observed and time to event. The safety of treatment with OE was analysed in terms of the number and severity of adverse events, their duration, treatment and outcome. RESULTS: For all symptoms except tumour pain, the adjusted mean improvement in symptom scores was larger in the test group than in the control group. The adjusted difference was statistically significant for all symptoms, except tumour pain and infections. The results show that the typical disease- and therapy-associated signs and symptoms in patients on complementary therapy with OE during postoperative treatment were significantly less. For 75% of the test group and 55% of the control group the physician recorded "no signs and symptoms". A clear reduction in the side effects of radiotherapy and chemotherapy was documented in 74% of the test group and 55% of the control group. Analysis of survival, recurrence, and metastasis demonstrated a reduced number of events in the test group. There was evidence of a beneficial influence of OE on time to event, although the median observation time was too short in these breast cancer patients to draw definite conclusions. The safety component was judged in 98% of the test group and 76% of the control group as "very good" or "good". In the total sample of 2,339 patients, the rate of OE-associated adverse reactions was 3.2%. All side effects were mild to moderate gastrointestinal symptoms. CONCLUSION: Complementary treatment of breast cancer patients with OE improves the quality of life by reducing signs and symptoms of the disease and the side effects of adjuvant antineoplastic therapies. This epidemiological retrolective cohort analysis provides evidence that the patients may also gain benefit by a prolongation of the time to event for cancer recurrence, metastasis and survival. OE was generally well tolerated.

Adolescent↗
PubMed2001

Breathhold unenhanced and gadolinium-enhanced magnetic resonance tomography and magnetic resonance cholangiography in hilar cholangiocarcinoma.

We assessed the imaging characteristics of hilar cholangiocarcinoma in magnetic resonance imaging (MRI) and magnetic resonance cholangiography (MRC). Breathhold MRI (T2-weighted turbo spin echo sequences, unenhanced T1-weighted gradient echo sequences, and gadolinium-enhanced fat-suppressed gradient echo sequences) and breathhold MRC (fat-suppressed two-dimensional projection images) performed in 12 patients with histologically confirmed hilar cholangiocarcinoma were retrospectively reviewed for morphological tumor characteristics and contrast enhancement patterns. MRC demonstrated a significant bile duct stenosis with intrahepatic bile duct dilatation in all cases except in one patient who received an endoprothesis prior to imaging. Hilar cholangiocarcinoma was diagnosed by MRC only in one patient and MRI and MRC in 11. Mass lesions were seen in nine patients and circumferential tumor growth in three, including the patient diagnosed by MRC only. The tumor appeared hypointense relative to liver parenchyma in 10 of 11 patients in unenhanced T1-weighted images. T2-weighted sequences showed isointense or only slightly hyperintense signal in 5 of 11 patients, 3 of whom demonstrated desmoplastic reactions by histology. The other 6 patients revealed strongly hyperintense signal intensities. Contrast enhancement was increased compared to liver in 5 of 11 patients and decreased in 6 of 11 patients. MRI with MRC seem to be a sensitive tools in the detection of hilar cholangiocarcinomas. The variable imaging characteristics are most probably related to the inhomogeneous histological appearance of this tumor entity.

Aged↗
PubMed2001

Glycoside carbamates from benzoxazolin-2(3H)-one detoxification in extracts and exudates of corn roots.

Zea mays was incubated with the natural phytotoxin benzoxazolin-2(3H)-one (BOA) to investigate the detoxification process. A hitherto unknown detoxification product, 1-(2-hydroxyphenylamino)-1-deoxy-beta-gentiobioside 1,2-carbamate (3), was isolated and identified. A reinvestigation of known BOA detoxification products by NMR methods led to the finding that the structure of benzoxazolin-2(3H)-one-N-beta-glucoside (1) first reported from Avena sativa has to be revised. In fact, the correct structure is that of the isomeric 1-(2-hydroxyphenylamino)-1-deoxy-beta-glucoside 1,2-carbamate 2, which is structurally related to 3. It was now shown with a synthetic mixture of 1 and 2 that 1 underwent spontaneous isomerization to form 2 in solution. Thus, N-glucosylation of BOA in the plant led finally to the carbamate 2. In contrast to BOA-6-O-glucosylation, BOA-induced N-glucosylation appears first after 6-8 h of incubation. As soon as N-glucosylation is possible, BOA-6-O-glucoside is not further accumulated, whereas the amount of glucoside carbamate increases continuously during the next 40 h. Synthesis of gentiobioside carbamate seems to be a late event in BOA detoxification. All detoxification products are released into the environment via root exudation.

Benzoxazoles↗