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Biomedical subjects

H Bauer

Publications and source records attributed to H Bauer.

At least 127 records · Page 7Linked to original sources
PubMed1996

Influence of the platelet-activating factor receptor antagonist BN52021 on endotoxin-induced leukocyte adherence in rat mesenteric venules.

The aim of this study was to investigate the influence of the platelet-activating factor (PAF) antagonist BN52021 on endotoxin-induced leukocyte-endothelium interactions and on venular microcirculation. The rates of leukocyte adherence and changes in red cell velocity, volumetric blood flow, vessel diameter, and venular shear rate were monitored in rat mesenteric venules following intravenous lipopolysaccharide (LPS) exposure (15 mg/kg body wt). The experiments were performed in LPS-treated control animals and in animals pretreated with the PAF receptor antagonist BN52021. LPS exposure induced a marked increase in adherent leukocytes in the control group compared to the BN52021-pretreated group. Thirty minutes after LPS injection, 6.1 +/- 0.8 leukocytes were adherent to 100 microns of venule in the control group compared to 2.5 +/- 0.5 in BN52021-pretreated animals (P < 0.01). The increased leukocyte adherence in the control group was accompanied by leukocytopenia. Red cell velocity, volumetric blood flow, vessel diameter, and venular shear rate did not differ between groups, indicating that increased leukocyte adherence in the control group was not due to diminished hydrodynamic dispersal forces. The attenuation of leukocyte adherence by the PAF receptor antagonist BN52021 suggests that PAF is involved in the mediation of the initial process of leukocyte sticking to the endothelium after LPS stimulation.

Animals↗
PubMed1996

Semi-continuous versus injectate cardiac output measurement in intensive care patients after cardiac surgery.

OBJECTIVE: Commercially available semi-continuous cardiac output (SCCO) monitoring systems are based on the pulsed warm thermodilution technique. There is evidence that SCCO fails to correlate with standard intermittent bolus cardiac output (ICO) in clinical situations with thermal instability in the pulmonary artery. Furthermore, ventilation may potentially influence thermodilution measurements by enhanced respiratory variations in pulmonary artery blood temperature and by cyclic changes in venous return. Therefore, we evaluated the correlation, accuracy and precision of SCCO versus ICO measurements before and after extubation. DESIGN: Prospective cohort study. SETTING: Intensive care unit (ICU) of a university hospital. PATIENTS AND PARTICIPANTS: 22 cardiac surgical ICU patients. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: SCCO and ICO data were obtained at nine postoperative time points while the patients were on controlled mechanical ventilation. Further sets of measurements were taken during the weaning phase 20 min before extubation, and 5 min, 20 min and 1 h after extubation. SCCO and ICO measurements yielded 286 data pairs with a range of 1.8-9.9 l/min for SCCO and 1.9-9.8 l/min for ICO. The correlation between SCCO and ICO was highly significant (r = 0.92; p < 0.01), accompanied by a bias of -0.052 l/min and a precision of 0.56 l/min. Correlation, accuracy and precision were not influenced by the mode of respiration. CONCLUSIONS: Our results demonstrate excellent correlation, accuracy and precision between SCCO and ICO measurements in postoperative cardiac surgical ICU patients. We conclude that SCCO monitoring offers a reliable clinical method of cardiac output monitoring in ICU patients following cardiac surgery.

Aged↗
PubMed1996

Acute, subchronic and discontinuation effects of zopiclone on sleep EEG and nocturnal melatonin secretion.

Zopiclone is a new short half-life cyclopyrrolone hypnotic agent acting at the GABA-benzodiazepine receptor complex. In order to characterize its pharmacological profile, the effects of 7.5 mg zopiclone on nocturnal melatonin secretion were investigated under polysomnographic control in 11 healthy subjects following acute and subchronic administration as well as after abrupt discontinuation of the drug. No effect of zopiclone on the melatonin plasma levels could be observed. Regarding both total melatonin production and the temporal pattern of melatonin secretion during the night, there was no difference between placebo baseline condition, acute and subchronic administration, and discontinuation. In contrast, the sleep EEG data demonstrated the hypnotic efficacy of zopiclone under acute administration and indicated a rebound insomnia after abrupt discontinuation. Moreover, alterations of sleep architecture were found under treatment as well as after discontinuation. Whereas, with regard to sleep EEG parameters, zopiclone appears to be comparable with some short-acting benzodiazepines, a discrepancy between the missing effect of zopiclone on pineal function and the suppressing influence of benzodiazepines known from the literature becomes obvious. The fact that zopiclone does not interfere with nocturnal melatonin secretion at pharmacologically active doses as indicated by alterations in sleep EEG parameters might possibly point to a pharmacodynamic difference between the two drug classes.

Adult↗
PubMed1996

[Premedication of coronary risk patients--results of a survey].

AIM: The perioperative risk in patients undergoing coronary artery bypass grafting (CABG) might be influenced by premedication procedures. This study was undertaken to evaluate present premedication regimens in CABG patients in Germany. METHODS: Using a detailed written questionnaire, each of the 58 German centres of cardioanaesthesia were asked to complete it. RESULTS: 37 (64%) of all questionnaires were returned and analysed. All centres used orally administered drugs for premedication in the evening before the operation. Flunitrazepam is the most often administered drug (54%), followed by dipotassium clorazepat (8%), and diazepam (8%). Premedication in the morning on the day of surgery is performed orally in 29 centres (78%), of which 18 centres (49%) prefer flunitrazepam and 6 centres (16%) midazolam as first choice. In contrast, 7 centres (19%) used intramuscularly administered regimens. 5 centres (14%) combined intramuscularly opioids with sedatives for that indication. If anaesthesia was induced late in the morning or in the afternoon, respectively, 11 centres (30%) administered additional benzodiazepines early in the morning. 68% of all centres maintained the administration of chronic treatment with ss-blockers until the morning of the operating day. Chronic treatment with nitrates is continued in 65%, treatment with calcium-channel blockers in 62%. Angiotensin converting enzyme inhibitors are continued in 30%, alpha 2-agonists in 27%, other antihypertensive drugs in 19%, and inotropic glycosids in 11%. 31 of 37 centres (84%) discontinued the administration of acetylsalicylic acid 5 or more days prior to surgery, but 68% tolerate individual exceptions from this principle. CONCLUSIONS: The results of our survey indicate that most of the German cardioanaesthesia centres use oral premedication regimens in patients undergoing coronary revascularisation. Anti-anginal medications, with the exception of anti-platelet agents, were continued until the day of surgery in most of the centres.

Cardiovascular Agents↗
PubMed1996

Differentiation of spontaneous canine breast tumors using dynamic magnetic resonance imaging with 24-Gadolinium-DTPA-cascade-polymer, a new blood-pool agent. Preliminary experience.

RATIONALE AND OBJECTIVES: The author assess the enhancement characteristics over time of spontaneous breast tumors in dogs comparing gadopentetate dimeglumine with a new blood-pool agent (24-gadolinium [Gd]-DTPA-cascade polymer). METHODS: Eighteen dogs with spontaneous breast tumors (5 carcinomas, 4 adenomas, and 9 benign mixed-tissue tumors) underwent dynamic magnetic resonance imaging after intravenous injection of gadopentetate dimeglumine and the blood-pool agent. Signal intensity time curves were followed up to 30 minutes after injection of both agents in the same animal. A nonlinear fitting routine enabled calculation of the delivery and clearance half lives of the contrast agent kinetics in each tumor. RESULTS: For gadopentetate dimeglumine, a fast signal increase was found immediately after intravenous injection, with a subsequent signal decay in all tumors. No difference was observed between the enhancement kinetics of different tumor types after gadopentetate dimeglumine application. Similar kinetics were found in benign lesions after injection of the blood-pool agent. However, in carcinomas the blood-pool agent displayed a slower delivery, delayed peak enhancement, and slower tumor tissue clearance or even a signal plateau of more than 30 minutes. CONCLUSIONS: Dynamic magnetic resonance imaging of breast neoplasms using a blood-pool agent may help to better differentiate between benign and malignant lesions because it demonstrates the enlarged interstitial space and increased capillary permeability in carcinomas.

Adenoma↗
PubMed1996

[Fetal weight-adjusted intrauterine IgG therapy in neonatal alloimmune thrombocytopenia].

Fetal alloimmune thrombocytopenia is caused by materno-fetal transfer of platelet antibodies. Since the thrombocytopenic fetus is threatened by intracranial hemorrhage, prenatal observation and, if necessary, treatment is required. However, the benefit of therapeutic options, including intravenous IgG (ivIgG), platelet transfusions or fetal IgG transfusions is still controversial. In this study we have evaluated the effect of intrauterine IgG and intraumbilical platelet transfusions on fetal platelet counts. All patients were multiparous women who were immunized against the Zwa antigen during previous pregnancies and had given birth to at least one severely thrombocytopenic infant. First umbilical blood was sampled at the 20th week of gestation. Fetal treatment of IgG was given, on av erage, over 9 weeks. In all cases, fetal IgG levels rose significantly whereas platelet counts did not increase following fetal IgG treatment. We conclude that fetal IgG infusions have no detectable effect on fetal allo-immune thrombocytopenia. Since platelet counts can be very low as early as 20 weeks of gestation, careful fetal monitoring by umbilical blood sampling is essential. Platelet transfusions in short intervals appear to be the only effective regimen to increase platelet counts in thrombocytopenic fetuses at risk.

Adult↗
PubMed1996

[Are their specific guidelines in surgical management in geriatric surgery?].

Progress in perioperative management, anesthesia, surgical technique and intensive care have led to a continuous reduction in risk for geriatric patients. Thus advanced age itself means no higher operative risk and should not be a cause for excluding the elderly from greater curative procedures. But it is necessary to define a special strategy of treatment which takes the special situation of the elderly into consideration. Older people are very often high risk patients because they must be operated with advanced diseases. Earlier operations in the elective state, therefore, have great significance in the prevention of geriatric surgery.

Aged↗
PubMed1995

Sequence of the porcine full-length cDNA encoding ribosomal protein rpS12.

The full-length cDNA encoding the porcine ribosomal protein rpS12 was shown to be differentially expressed in endothelial and smooth muscle cells. A cDNA clone containing the entire rpS12 sequence was isolated from growth-stimulated capillary endothelial cells by use of subtractive hybridization and differential screening. The porcine rpS12 cDNA coding region exhibits 94% identity to the rat rpS12 and 92% to the human rpS12 cDNAs.

Amino Acid Sequence↗
PubMed1995

Ontogenic expression of the erythroid-type glucose transporter (Glut 1) in the telencephalon of the mouse: correlation to the tightening of the blood-brain barrier.

Since Glut 1 was shown to be highly abundant in brain microvessels, its distribution during early developmental stages seems of importance in respect to the timing of blood-brain barrier (bbb) formation in the developing CNS. Here we have followed the temporal expression of the erythroid-type glucose transporter Glut 1 in the telencephalon of the embryonic and newborn mouse, beginning at the 9th intrauterine day. Glut 1 immunofluorescence staining was done on cryosections using a rabbit polyclonal antiserum to purified human erythrocyte glucose transporter. Endothelial cells resp. capillaries were detected by staining with a rhodamin-coupled Bandeiraea simplicifolia lectin (BSL). In parallel, the developmental tightening of the embryonic bbb was assessed by perfusion of mouse embryos with Trypan blue and horse radish-peroxidase. At E9, prior to the onset of intraneural neovascularization, strong Glut 1 immunoreactivity was found in the whole neuroectoderm but only minor staining was seen in the perineural domain. Glut 1 expression remained uniformly distributed in the intraneural tissue at E10, the beginning of intraneural neovascularization in the mouse. From E11 onwards, Glut 1 immunoreactivity was invisible in neuroepithelial cells, but appeared tightly associated with intraneural capillaries. Perfusion of E12 embryos using trypan blue solution and HRP revealed that most parts of the CNS and spinal cord were impermeable to the tracer substances at that stage. Thus, we suggest that the bbb is established very early in CNS development, probably in the course of intraneural neovascularization. In addition, our data indicate that the restriction of Glut 1 expression to the intraneural capillaries reflects the onset of bbb function in the mouse embryo.

Animals↗
PubMed1995

Developmental changes in the phenol concentrations of 'golden delicious' apple fruits and leaves.

The phenolic content of apple fruit skin and leaves was determined at the developmental stage of each organ. Phenolic levels decreased on a dry weight basis during the seasonal development of fruits and leaves with respect to their ontogenesis but the single compounds did not behave uniformly. A shift in flavanol pools from monomeric to oligomeric structures during fruit growth indicated the biosynthetic tendency towards the formation of procyanidins at the end of the growing period. Among the procyanidins identified epicatechin-(4 beta,6)-epicatechin-(4 beta,6)-epicatechin has not been reported previously from apple.

Chromatography, High Pressure Liquid↗
PubMed1995

Ketamine attenuates endotoxin-induced leukocyte adherence in rat mesenteric venules.

OBJECTIVES: To determine the influence of ketamine on endotoxin-induced leukocyte adherence and venular microhemodynamics. DESIGN: Randomized, controlled trial. SETTING: Experimental laboratory. SUBJECTS: Thirty male Wistar rats. INTERVENTIONS: The rats were pretreated with ketamine (10 mg/kg iv) or 0.9% saline, and both groups were given endotoxin (Escherichia coli lipopolysaccharide; 5 mg/kg iv). The control group received two doses of 0.9% saline. MEASUREMENTS AND MAIN RESULTS: The rates of leukocyte adherence and changes in microhemodynamics were monitored in rat mesenteric venules, using in vivo video microscopy. The number of adherent leukocytes was determined on-line in 10-min intervals from 60 mins before until 2 hrs after endotoxin administration. Venular diameters, red blood cell velocity, volumetric blood flow, and the venular wall shear rate were monitored before and at 10, 30, and 60 mins after endotoxin exposure. A 6.3-fold increase in the number of adherent leukocytes was observed 10 mins after administration of endotoxin when compared with control animals (5.87 +/- 0.69 vs. 0.93 +/- 0.21 adherent cells/100 microns; p < .001). This increase remained unchanged for 120 mins. In ketamine-pretreated rats, a 2.6-fold increase in leukocyte adherence occurred during the first 20 mins after endotoxin exposure (2.40 +/- 0.46 vs. 0.93 +/- 0.21 adherent cells/100 microns; p < .01). However, no difference in the number of adherent leukocytes between ketamine-pretreated and control animals was found after this 20-min period. In animals of the control group, no increase in leukocyte adherence occurred during the entire observation time. Diameters of mesenteric venules did not change after endotoxin exposure in any of the groups. Red blood cell velocity and venular blood flow in the endotoxin-treated groups decreased 10 mins after the injection of endotoxin when compared with controls, but these values did not show any difference when they were compared between ketamine and saline-pretreated animals. Similarly, venular wall shear rate in the endotoxin-treated groups decreased 10 and 30 mins after injection of endotoxin. However, no significant difference occurred between ketamine and saline-pretreated animals. CONCLUSIONS: Pretreatment with ketamine attenuates endotoxin-induced leukocyte adherence by a shear rate-independent mechanism, suggesting reduced expression of adhesion molecules. These results indicate that ketamine exerts an anti-inflammatory effect, which might be beneficial in septic patients.

Animals↗
PubMed1995

[A retroperitoneal hydatid cyst--a rare manifestation of Echinococcus granulosus].

A rare case of a retroperitoneal cyst of Echinococcus granulosus in a male adult is presented. Due to its extension and infiltration of important anatomical structures the hydatid cyst could not be completely removed by operation. Therefore the patient was treated with albendazole for 10 months after surgery. The efficiency of this combined therapy was documented by CT-scan, specific blood tests and histopathological findings.

Albendazole↗