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B Schneider

Publications and source records attributed to B Schneider.

At least 163 records · Page 9Linked to original sources
PubMed2000

Shape analysis of tumor cell nuclei in ependymomas by means of Fourier analysis.

OBJECTIVE: To study the prognostic significance of nuclear shape analysis in ependymomas. STUDY DESIGN: Tumor cell nuclei in surgical specimens of primary resected ependymomas from 30 patients were evaluated by means of Fourier analysis of nuclear contours, conventional morphometric features (nuclear area, shape factor) and the Ki-67 proliferation index. Fourier analysis can be used for decomposing an irregular nuclear contour by calculating "Fourier amplitudes." Tumors with different tumor grades according to the World Health Organization were compared, as were patients with and without recurrence of ependymomas. Planimetric data were further correlated with the Ki-67 index. RESULTS: t Test and multivariate analysis showed distinct differences between ependymomas with tumor grade 3 and the other tumor grades. Cross-validated, stepwise discriminant analysis with the event of recurrence as grouping variable revealed correct reclassification in 16/18 cases without recurrence and of 10/12 cases with recurrence. When considering just intracranial ependymomas with total surgical removal, Fourier amplitudes provided 100% correct reclassification concerning recurrence. Proliferation index, in contrast, showed considerable overlap between all tumor grades and between cases with and without recurrence. CONCLUSION: Quantification of the shape of tumor cell nuclei in ependymomas by means of Fourier analysis has prognostic significance and seems to be superior to the Ki-67 index.

Brain Neoplasms↗
PubMed2000

[p53 gene mutation in cancer of the colon and rectum].

BACKGROUND: Genetic events associated to colorectal carcinoma are well characterized, but there is scanty information about this issue in Chilean subjects. AIM: To determine the frequency and distribution of exons 5, 6, 7, 8 and 9 mutations and the immunohistochemical expression of p53 gene in biopsy samples of colorectal carcinoma. MATERIAL AND METHODS: p53 gene exons 5, 6, 7, 8 and 9 were directly sequenced in 42 biopsy samples of colorectal carcinoma. Immunohistochemical expression of p53 was determined in 35 samples. RESULTS: Thirty one discrete mutations (12 transitions, 11 transversions and 8 insertions) were observed in 21 samples (60%). Nine samples had mutations in exon 5, twelve samples had mutations in exon 6, seven samples had mutations in exon 7 and three samples had mutations in exons 8 and 9. Immunohistochemical expression of p53 protein was observed in 18 of 35 cases. There was a high correlation between the genetic alteration and immunohistochemistry, when p53 was expressed in more the 20% of cells. The positive and negative predictive values of p53 expression were 87 and 80% respectively. There was a non significant lower mortality among patients with mutations in their biopsies. CONCLUSIONS: These results confirm the involvement of p53 gene mutations in colonic carcinogenesis. Immunohistochemical methods for the detection of p53 protein have a high predictive value.

Adenocarcinoma↗
PubMed1999

Bronchodilation using combined urodilatin - albuterol administration in asthma: a randomized, double-blind, placebo-controlled trial.

Urodilatin, the renal form of natriuretic peptide type A, induces bronchodilation, increasing intracellular cyclic guanosine monophosphate (cGMP), whereas the bronchorelaxant effect by b2-agonists is triggered by cyclic adenosine monophosphate (cAMP). The objective of this investigation is to demonstrate the efficacy of urodilatin in inducing bronchodilation, and to show this activity alone or in combination with albuterol. Therefore, a randomized, double-blind, placebo-controlled, dose-finding study with cross-over design was carried out including 12 stable, mild to severe (step 2 to 4, definition by NIH/NHLBI guideline 1997) asthmatics. 96 treatments were thus performed. The intervention was comprised of an intravenous infusion of urodilatin (0, 10, 30, or 60 ng/kg/min) combined with inhaled albuterol (0 or 200 microg). As primary objective, the increase in forced expiratory volume in one second (FEV subset1) was measured. - The trial shows that urodilatin at all applied doses or 200 microg albuterol significantly increases FEV subset1 (p < 0.05). Combination of urodilatin and albuterol treament significantly improves FEV subset1 (p < 0.05) compared to either monotherapy and results in maximum bronchodilation. - From the results, the following conclusions can be drawn. In stable asthmatics, the combined activation of cGMP- and cAMP-mediated pathways results in a significantly improved, maximal bronchodilation in comparison to either type of monotherapy. This shows that urodilatin combined with albuterol improves lung function and ameliorates the therapy in asthmatics.

Adult↗
PubMed1999

[The prognostic value of dobutamine stress echocardiography. A long-term follow-up study].

BACKGROUND AND OBJECTIVE: The prognostic value of dobutamine stress echocardiography in patients with suspected or known coronary heart disease has not exactly been assessed. Purpose of the study was the assessment of the prognostic value of DSE regarding cardiac events, especially in patients with a normal DSE finding. PATIENTS AND METHODS: 316 patients (168 men, 148 women, mean age 61 +/- 10 years), included in this follow-up study, underwent DSE between January 1994 and December 1996 to evaluate clinically suspected or known coronary heart disease. DSE was classified according to resting and stress echocardiography as either "normal-normal (NN)", "normal-ischemic (NI)", "abnormal-normal (AN)", "abnormal-ischemic (AI)" or "inconclusive (C)". Follow-up by telephone took place between June 1997 and April 1998. "Events" were survived myocardial infarction and death. "Interventions" were revascularisation procedures, either percutaneous transluminal coronary angioplasty (PTCA) with or without stenting or aortocoronary bypass surgery. RESULTS: In 161 patients, DSE was NN, NI in 27 patients, AN in 55 patients, AI in 54 patients and C in 19 patients. Mean follow-up duration was 28 months. Events occurred in 23 patients: survived myocardial infarction in 10, death in 13 persons. Interventions were carried out in 50 patients: PTCA with or without stenting in 19, aortocoronary bypass surgery in 31 persons. The event rate was significantly lower in patients with DSE classified as NN (P = 0.03 by log-rank) than in other groups. The intervention rate was significantly lower in the NN-group (P = 0.0001 by log-rank) than in the other groups, too. CONCLUSION: Patients with a normal rest echocardiography and DSE had a good prognosis in a long-term follow-up study.

Adult↗
PubMed1999

Nucleophilic activation by positioning in phosphoryl transfer catalyzed by nucleoside diphosphate kinase.

The nonenzymatic reaction of ATP with a nucleophile to generate ADP and a phosphorylated product proceeds via a dissociative transition state with little bond formation to the nucleophile. Consideration of the dissociative nature of the nonenzymatic transition state leads to the following question: To what extent can the nucleophile be activated in enzymatic phosphoryl transfer? We have addressed this question for the NDP kinase reaction. A mutant form of the enzyme lacking the nucleophilic histidine (H122G) can be chemically rescued for ATP attack by imidazole or other exogenous small nucleophiles. The ATP reaction is 50-fold faster with the wild-type enzyme, which has an imidazole nucleophile positioned for reaction by a covalent bond, than with H122G, which employs a noncovalently bound imidazole nucleophile [(kcat/KM)ATP]. Further, a 4-fold advantage for imidazole positioned in the nucleophile binding pocket created by the mutation is suggested from comparison of the reaction of H122G and ATP with an imidazole versus a water nucleophile, after correction for the intrinsic reactivities of imidazole and water toward ATP in solution. X-ray structural analysis shows no detectable rearrangement of the residues surrounding His 122 upon mutation to Gly 122. The overall rate effect of approximately 10(2)-fold for the covalent imidazole nucleophile relative to water is therefore attributed to positioning of the nucleophile with respect to the reactive phosphoryl group. This is underscored by the more deleterious effect of replacing ATP with AlphaTauPgammaS in the wild-type reaction than in the imidazole-rescued mutant reaction, as follows. For the wild-type, AlphaTauPgammaS presumably disrupts positioning between nucleophile and substrate, resulting in a large thio effect of 300-fold, whereas precise alignment is already disrupted in the mutant because there is no covalent bond to the nucleophile, resulting in a smaller thio effect of 10-fold. In summary, the results suggest a catalytic role for activation of the nucleophile by positioning in phosphoryl transfer catalyzed by NDP kinase.

Adenosine Diphosphate↗
PubMed1999

Expression of granulocyte colony-stimulating factor in recurrent glial tumors is inversely correlated with tumor progression.

We have previously reported that in vivo-expression of granulocyte colony-stimulating factor (G-CSF) is a characteristic feature of reactive and neoplastic astrocytes. The aim of the present study was to analyze the expression of G-CSF protein in primary and recurrent astroglial, oligodendroglial and mixed glial-differentiated tumors. G-CSF expression was present in all GFAP-positive tumors excepting glioblastomas. G-CSF expression was significantly reduced in recurrent tumors more dedifferentiated than their primary counterparts. G-CSF expression was absent in all GFAP-negative tumors such as oligodendrogliomas. Our results demonstrate that G-CSF is a highly sensitive differentiation marker of neoplastic astrocytes, which is lost during tumor progression.

Adolescent↗
PubMed1999

Acute effect of leptin on hepatic glycogenolysis and gluconeogenesis in perfused rat liver.

Leptin circulates in blood and is involved in body weight control primarily via hypothalamic receptors. To examine its direct metabolic action, effects of short-term portal leptin infusion: 1) on postprandial basal and epinephrine-stimulated glycogenolysis; and 2) on postabsorptive lactate-stimulated gluconeogenesis were studied in isolated perfused rat livers. Incremental epinephrine (150 pmol x min-1 x g-1 liver)-stimulated glucose release (in micromol/g liver within 30 minutes; control: 28.3 +/- 2.8) was suppressed (P <.05) by 44% (15.8 +/- 1.6), by 48% (14.6 +/- 4.1), and by 53% (13.3 +/- 2.1) during insulin (3 pmol x min-1 x g-1 liver), leptin (30 pmol x min-1 x g-1 liver), and simultaneous leptin + insulin infusion. Perfusate cyclic adenosine monophosphate increased approximately twofold during epinephrine stimulation in all groups. Neither leptin nor insulin affected hepatic lactate production, bile flow, or portal pressure in the fed state. In the postabsorptive state (20-hour fasting), rates of lactate (10 mmol/L)-dependent hepatic glucose release (in micromol. min-1 x g-1 liver; control: 0.12 +/- 0.01) were increased (P <.01) to 0.35 +/- 0.02 and to 0.24 +/- 0.01 by glucagon (3 pmol x min-1 x g-1 liver) and by leptin (15 pmol x min-1 x g-1 liver), respectively. In parallel, lactate uptake rates (in micromol x min-1 x g-1 liver) were higher in the presence of both glucagon (0.90 +/- 0. 03) and leptin (0.84 +/- 0.02) compared with control (0.68 +/- 0.04). In conclusion, leptin modulates hepatic glucose fluxes and may contribute to direct humoral regulation of liver glycogen stores in the fasted as well as in the fed state.

Adipose Tissue↗
PubMed1999

Brassinosteroids.

Explore the source record for details and available documents.

Brassinosteroids↗
PubMed1999

Cephalometric differentiation between vertical and horizontal malocclusions in 122 Europeans using the Denture Frame Analysis and standard measurements. Differentiation between vertical and horizontal malocclusion.

This study evaluated the ability of some cephalometric measurements to differentiate between horizontal and vertical malocclusions and normal occlusion. Based upon the Angle classification and the vertical incisor overbite, 122 randomly selected subjects were assigned to 3 horizontal and 3 vertical groups: neutrocclusion, distocclusion, mesiocclusion as well as open bite, normal overbite, and deep bite. Evaluation of the lateral cephalograms was based on Denture Frame Analysis and cephalometric standard measurements (SNA, SNB, ANB, Wits appraisal, Björk polygon, overbite depth indicator, incisor inclination, incisor protrusion, facial height ratio). The statistical evaluation assessed the ability of the measurements to show significant differences between the individual horizontal and vertical groups. Using Denture Frame Analysis, all vertical groups could be differentiated by the occlusomandibular angle (OP-MP) and all horizontal groups by the angle between the A-B plane and the mandibular plane as well as by the inclination of the upper incisors to the A-B plane with statistical significance (p < 0.05). Among the standard measurements, the Wits appraisal was the only one to show differences between all horizontal groups with statistical significance. None of the standard measurements could fully differentiate the vertical groups. The above measurements from the Denture Frame Analysis distinguished the types of malocclusion in anteroposterior and vertical direction including significant distinction between the neutrocclusion group and the malocclusion groups. Therefore a cephalometric classification was feasible in terms of hyper- and hypodivergence as well as of a mesial or distal dentofacial relationship.

Adolescent↗
PubMed1999

Long-term follow-up of patients after related- and unrelated-donor bone marrow transplantation for chronic myelogenous leukemia.

Between January 1983 and December 1997, 88 patients (36 female, 52 male, median age 37 years, range 19-57) with chronic myelogenous leukemia (CML) underwent allogeneic bone marrow transplantation (BMT) at the University Hospital of Vienna. Sixty patients were in chronic phase, 18 in accelerated phase, and ten in blast crisis. Marrow donors were HLA-identical siblings for 64 patients (BM 58, PBSC 6), 2-antigen-mismatched related donors (RD) for two, HLA-identical unrelated donors (URD) for 17, and 1-antigen-mismatched URD for five. The median time from diagnosis to BMT was 22 months (range 2-91), and 63 patients had received prior interferon (IFN)-alpha therapy, 46 (73%) for more than 6 months. Conditioning therapy consisted of cyclophosphamide (CY) and total body irradiation (TBI) in 71 patients and CY and busulfan (BU) in 16. One patient received etoposide and TBI. For graft-versus-host disease (GVHD) prophylaxis methotrexate (MTX) was given to 12 patients, MTX and cyclosporin A (CSA) to 67, CSA alone to four, and CSA and methylprednisolone to five. Durable engraftment was documented in 80 of 82 patients (98%). As of December 31, 1997, 52 patients (59%) were alive, 38 (58%) after sibling transplantation with a median observation time of 73 months and 14 (64%) after URD transplantation with a median observation time of 12 months. Probability of overall survival is 59%, for patients undergoing transplantation in chronic phase and 44% for patients undergoing transplantation in advanced stage CML. Probability of disease-free survival (DFS) after sibling and URD BMT is 55% and 59%, respectively. Ten patients (12%) experienced relapse of CML. Transplant-related mortality was 32% both after RD and after URD transplantation. Acute GVHD occurred in 53 of 80 evaluable patients (66%), consisting of grade III or IV in 14 patients (18%). Chronic GVHD developed in 40 of 63 eligible patients (63%), including extensive disease in 26 patients (41%). Thus, sibling and URD BMT offer high cure rates with acceptable toxicity to patients with CML.

Acute Disease↗
PubMed1999

Changes of laboratory markers of cognitive brain function by thermostimuli in the elderly.

OBJECTIVE: Plain external applications of physical stimuli, which are used quite commonly in geriatric care in Germany, have not been studied for their influence on cognitive brain function. The aim of this randomized crossover study was to examine the influence of dermatoreceptive stimuli on cognitive brain function in healthy geriatric volunteers. METHODS: Twenty-four healthy volunteers (23 women, 1 man) were randomized into two groups (crossover design). Group A (mean age, 68.8+/-6.2 [SD] years) was treated with a 10 degrees C to 12 degrees C cold stimulus for 10 seconds (a so-called "Kneipp face shower"), followed by a cold 10 degrees C to 12 degrees C wetpack at the neck for 1 minute. Group B (mean age, 69.8+/-5.3 [SD] years) was subjected to an identical procedure but with warm to neutral temperatures of 34 degrees C to 36 degrees C. After I week the two groups were interchanged. The parameters of interest were the critical flicker frequency (CFF) and the latencies of the event-related P-300 potentials of the visual evoked potentials (VEP), which can be considered an electroencephalographic marker of the cognitive functional ability. The CFFs and the P-300 latencies and amplitudes were measured directly both before and 10 minutes after the application of the respective stimuli. In addition, the CFFs were recorded 30 and 60 minutes later. RESULTS: After cold water stimuli were applied, the CFF increased from 32.55+/-2.26/sec (mean+/-SD) to 33.06+/-2.25/sec (p = .003) 10 minutes after the stimulus. Thirty minutes later the CFF was still elevated at 32.95+/-2.3/sec (p = .043). The P-300 latencies, after cold water application, decreased by 4.8% (p < .001), from 266.5+/-21.1msec (mean+/-SD) to 253.7+/-16.9msec. After warm stimuli they increased from 258.69+/-14.8msec to 266.17+/-20.1msec (p = .01). The P-300 amplitudes were significantly elevated, by 5% (p = .004), only after cold stimuli. CONCLUSION: Cold water applied locally to the face and neck region can provoke significant changes in electroencephalographic markers as measured by an electroencephalographic marker (VEP and P-300 latency) and, by inference, may help to improve cognitive function in the elderly.

Aged↗
PubMed1999

Mnestic block syndrome.

The case of a patient with largely preserved intelligence, but severe and persistent memory impairments is reported. FA, a 46-year-old patient with the diagnosis of prolonged depression was investigated repeatedly over a two year period with neuroradiological, neuropsychological, neuromonitoring and other methods. While no brain damage was detectable in FA, he manifested continued and severe anterograde and retrograde memory disorders together with an inhibition in his thinking processes. Otherwise, his intellectual capabilities were in the normal range, that is he was not pseudo-demented. Various approaches with drug treatment and psychotherapy failed to improve his condition. The condition is interpreted as 'mnestic block syndrome' and is considered to be related to an altered brain metabolism which may include changes in various transmitter and hormonal systems (GABA-agonists, glucocorticoids, acetylcholine). Whether depression contributes to this syndrome is uncertain from FA's cognitive performance, but may be a possibility.

Amnesia, Retrograde↗
PubMed1999

Laser Doppler imaging and capillary microscopy in ischemic ulcers.

The local distribution of laser Doppler flux (mainly thermoregulatory perfusion) and capillary density (nutritive circulation) within 25 ischemic leg ulcers and their adjacent skin were investigated. For this purpose the technique of laser Doppler imaging and capillary microscopy were applied. In each ulcer a non granulation tissue area (NGTA), a granulation tissue area (GTA) and in adjacent skin a skin area (SA) were defined. In these areas the average laser Doppler area flux (arbitrary units, AU) and the number of capillaries/mm2 were determined for each patient. The mean+/-S.D. of laser Doppler area fluxes were: NGTA 1.30+/-1.93, GTA 2.13+/-1.53 and SA 1.21+/-0.77 AU, respectively. The differences between GTA and NGTA or SA was statistically significant (p < 0.001, each) The mean+/-S.D. of capillary densities were as follows: NGTA: 0.56+/-2.06, GTA 6.76+/-8.39 and SA 16.80+/-7.38 capillaries/mm2, respectively. The following differences were statistically significant: NGTA versus GTA (p < 0.01) and SA versus NGTA or GTA (p < 0.001, each). In conclusion following characteristics of the three areas can be described: In NGTA low laser Doppler area flux is combined with very low capillary density (ulcer area without healing). In GTA the highest laser Doppler area flux of all three areas and an intermediate capillary density (wound healing) is found. In SA an intermediate laser Doppler area flux is associated with the highest capillary density of all three areas with the healing process nearly completed and no granulation tissue.

Aged↗
PubMed1999

Guided versus unguided mandibular movement for duplicating intraoral eccentric tooth contacts in the articulator.

STATEMENT OF PROBLEM: The extent to which intraoral excursive tooth contacts are duplicated correctly in the articulator is constantly being investigated. PURPOSE: This study evaluated whether data from unguided or guided hinge axis movement are superior in duplicating excursive tooth contacts. MATERIAL AND METHODS: Intraoral records of tooth contacts from intercuspal position to 4 mm protrusion and laterotrusion were obtained from 50 subjects by using occlusogram wax. These movements were simulated in a SAM2 "P" articulator using horizontal condylar inclination and Bennett angle from recorded guided and unguided mandibular movements. Occlusograms were compared with contacts generated by the articulator. RESULTS: On average, the articulator duplicated approximately 73% of intraoral protrusive and 81% of intraoral laterotrusive contacts for up to 4 mm of movement, using either data from unguided or guided movements. Both movements yielded identical means and no significant difference of duplicated contacts. However, individual differences scattered within approximately +/-32%. CONCLUSION: Exclusive recommendation of guided movement can be questioned for accurate imitation of dynamic tooth contacts. In addition to the type of movement, other factors must be detected to enhance articulator adjustment and workings.

Adolescent↗
PubMed1999

Tidal peritoneal dialysis for home-treated patients: should it be preferred?

Tidal peritoneal dialysis (TPD) was introduced to increase the efficacy of peritoneal dialysis. We measured peritoneal clearances of small solutes and beta2-microglobulin, peritoneal protein loss, and efficacy of ultrafiltration in 30 patients during TPD and intermittent peritoneal dialysis (IPD) with low-dialysate flow (1.7 L/h) and, in addition, in 17 of these patients using a high-dialysate flow (3 L/h). Using a low-dialysate flow, patients with low/low average peritoneal transport rates showed significantly better peritoneal creatinine and urea nitrogen clearances during IPD compared with TPD, whereas there was no difference between these two treatment modalities in high/high average transporters. With high-dialysate flow, peritoneal clearances of creatinine and urea nitrogen were similar between TPD and IPD independent of peritoneal transport type. Clearances of phosphate and beta2-microglobulin were similar between TPD and IPD independent of dialysate flow or peritoneal transport type. Increasing the dialysate flow rate led to a significant increase in small-solute clearances, but not beta2-microglobulin clearances, in both peritoneal transport types. Total peritoneal protein and albumin losses were similar between TPD and IPD only with low-dialysate flow. However, using a high-dialysate flow, total protein losses tended to increase in both transport types during IPD compared with TPD. In conclusion, up to a dialysate flow of 3 L/h, TPD did not provide better small-solute or middle-molecule clearances compared with IPD. Moreover, using a low-dialysate flow, IPD was superior to TPD in low/low average transporters.

Adult↗
PubMed1999

Influence of the preceding exchange on peritoneal equilibration test results: a prospective study.

The standard peritoneal equilibration test (PET) should be performed after a long overnight dwell, which is easily possible in continuous ambulatory peritoneal dialysis patients. However, for such a procedure, patients undergoing automated peritoneal dialysis or daily ambulatory peritoneal dialysis have to change their regimen and, in the case of high peritoneal transport rates, run the risk for fluid absorption. We compared dialysate to plasma ratios (D/P) of creatinine, blood urea nitrogen (BUN), phosphate, sodium, total protein, and albumin measured during PET after an 8- to 11-hour dry period (PET dry), after a preceding exchange with a long dwell time (PET standard), and immediately after tidal peritoneal dialysis (PET tidal). D/P ratios of creatinine, BUN, phosphate, and sodium at 2 and 4 hours were greater during PET dry compared with both PET standard and PET tidal. The quotient of dialysate glucose at 2 hours to dialysate glucose at time point 0 was significantly less in PET dry compared with both PET tidal and PET standard. During the first 2 hours of PET, the increase of D/P curves of creatinine and BUN, as well as phosphate, was significantly steeper in PET dry than PET tidal and PET standard. D/P ratios of albumin and protein were greatest in PET dry and least in PET tidal. There was a significant difference between all three PETs at 0, 2, and 4 hours of dwell time. PET curves were significantly steeper during PET dry compared with PET tidal in case of D/P protein (during the first 2 hours of dwell time) and D/P albumin (during the entire dwell time). Similar differences between the PET curves of protein and albumin were observed between PET dry and PET standard. These data clearly indicate a dry period before PET significantly influences the D/P ratios of small solutes, protein, and albumin measured during the test.

Adult↗