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Biomedical subjects

Markus Schneider

Publications and source records attributed to Markus Schneider.

6 recordsLinked to original sources
PubMed2003

A meta-analysis of the effects of treatment on left ventricular mass in essential hypertension.

PURPOSE: Antihypertensive medications have different effects on left ventricular mass. We conducted a meta-analysis of double-blind trials that measured the effects of antihypertensive therapy on left ventricular mass. METHODS: Medical databases and review articles were screened for double-blind, randomized controlled trials (through September 2002) that reported the effects of diuretics, beta-blockers, calcium antagonists, angiotensin-converting enzyme (ACE) inhibitors, or angiotensin II receptor antagonists on echocardiographic left ventricular mass in essential hypertension. Treatment arms of the same drug class, weighted for the number of patients, were combined. Analysis of covariance was performed to detect differences among drug classes in effects on left ventricular structure. RESULTS: Eighty trials with 146 active treatment arms (n = 3767 patients) and 17 placebo arms (n = 346 patients) were identified. Adjusted for treatment duration and change in diastolic blood pressure, there was a significant difference (P = 0.004) among medication classes: left ventricular mass index decreased by 13% with angiotensin II receptor antagonists (95% confidence interval [CI]: 8% to 18%), by 11% with calcium antagonists (95% CI: 9% to 13%), by 10% with ACE inhibitors (95% CI: 8% to 12%), by 8% with diuretics (95% CI: 5% to 10%), and by 6% with beta-blockers (95% CI: 3% to 8%). In pairwise comparisons, angiotensin II receptor antagonists, calcium antagonists, and ACE inhibitors were more effective at reducing left ventricular mass than were beta-blockers (all P <0.05 with Bonferroni correction). CONCLUSIONS: Antihypertensive drug classes have different effects on left ventricular mass reduction. Whether a greater reduction of left ventricular mass results in better clinical outcomes remains to be determined.

Adrenergic beta-Antagonists↗
PubMed2003

Computer simulation of Lorentz electron micrographs of thin magnetic particles.

Lorentz electron microscopy is a powerful tool for high-resolution studies of magnetic structures, not only in continuous thin films, but also in spatially limited, i.e. individual particles. In addition to the experimental studies of magnetic particulate media it is interesting to simulate images in order to compare them with experimental results, as it is practiced in high-resolution electron microscopy. This paper introduces a software package which simulates the Lorentz microscopical image of magnetic structures in thin particles. While other simulation programs deal with infinite magnetic films with homogeneous thickness, the major difference in our calculation is that we take into account the finite dimensions of the particle for specimens of various sizes and shapes. That means the phase shift due to the inner potential depending on the geometrical shape of a magnetic particle is added to the phase shift depending on its magnetic microstructure. The following article presents the computation methods and its results and compares it with experimental findings.

Journal Article↗
PubMedDate not supplied

Highly efficient expansion of human CD4+CD25+ regulatory T cells for cellular immunotherapy in patients with graft-versus-host disease.

CD4+CD25+ regulatory T cells (T(REG)) are engaged in the regulation of murine and human immune responses as well as graft-versus-host disease (GvHD) after allogeneic stem-cell transplantation. Despite their suppression of GvHD they do not impair graft-versus-tumor activity in the mouse, which makes T(REG) especially attractive candidates for cellular immunotherapy. T(REG) comprise only 5% to 10% of CD4+ T cells in peripheral blood and are naturally anergic, which prevented their use as therapeutic suppressor cells in the context of autoimmune or alloimmune reactions so far. We therefore developed an in vitro expansion protocol for human T(REG), breaking their anergy with anti-CD3/anti-CD28-coupled paramagnetic beads and a combination of interleukin (IL)-2 and IL-15. Highly purified human T(REG) can be expanded 285-fold to 1000-fold within 20 days and keep their phenotype as well as all their suppressor functions even in the context of stimulation with mature allogeneic dendritic cells. However, we demonstrate that FoxP3 is not a reliable marker for human T(REG) as it is transiently inducible in CD4+CD25- cells upon activation with cytokines or via their T cell receptor. In addition, we successfully expanded CD4+CD25+ cells from patients after allogeneic stem-cell transplantation with or without GvHD and show that different suppressor functions might be lost independently, demonstrating that human T(REG) biology is likely more complicated than previously thought.

Adult↗
PubMedDate not supplied

Influence of volume preloading on uteroplacental and fetal circulation during spinal anaesthesia for caesarean section in uncomplicated singleton pregnancies.

OBJECTIVE: Effects of volume preloading during spinal anaesthesia for elective caesarean section on maternal blood pressure, feto-maternal circulation and fetal outcome. PATIENTS AND METHODS: In a pilot study a randomised trial was performed in 22 healthy women with uncomplicated, singleton pregnancies at 36-40 weeks of gestation undergoing elective caesarean section under spinal anaesthesia. In the low volume group (group A) patients received 150 ml of crystalloid solution for preloading, in the high volume group (group B) they were given 15 ml/kg of crystalloid solution for preloading before the initiation of spinal anaesthesia. Maternal blood pressure was monitored intermittently. Hypotension was defined as a decrease in systolic pressure to less than 80% of the baseline value. The Doppler flow evaluation consisted of measurements from the uterine artery at the placental site, fetal umbilical artery and fetal middle cerebral artery. Pulsatility indices were derived before and after fluid preloading, and when spinal anaesthesia was established. The neonatal outcome was assessed by Apgar scores, arterial acid base status and neurologic and adaptive capacity scores (NACS). RESULTS: The incidence of maternal hypotension in both groups was 45.5% (n = 10); 3 cases occurred in group A compared to 7 cases in group B (n.s.). There was no evidence that the high dose volume is useful in preventing maternal hypotension. The pulsatility indices of uterine arteries, umbilical arteries and middle cerebral arteries were not altered. Statistical analysis showed no changes in neonatal outcome concerning umbilical arterial pH, Apgar score and NACS (n.s.) between groups A and B. CONCLUSIONS: Our preliminary results suggest that high dose crystalloid volume preloading has no preventive function in the avoidance of maternal hypotension in healthy parturients undergoing elective caesarean section under spinal anaesthesia, and shows no harmful effects on neonatal outcome as long as maternal hypotension is corrected immediately. However, the statistical significance may reflect the small sample size, and larger series are needed before changing the current management.

Anesthesia, Spinal↗