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Biomedical subjects

B Osswald

Publications and source records attributed to B Osswald.

11 recordsLinked to original sources
PubMed2006

Coronary reconstructive surgery versus coronary artery bypass grafting--a documentation gap.

OBJECTIVE: Over the last years, there has been a clear trend that an increasing number of patients are admitted for CABG with advanced disease, complex pathomorphological alterations and impaired left ventricular function. The necessity of performing extensive reconstructive coronary surgery rather than coronary bypass grafting, in its original sense, is not appropriately documented by the current version of the German Documentation System for Cardiac Surgery, nor in other national and international documentation systems. PATIENTS AND METHODS: 5821 consecutive, unselected patients underwent isolated CABG from 7/1995 through 12/2003 at a single institution. A closing date follow-up procedure up to 8 years postoperatively was performed with a completeness of 98.8%. RESULTS: The need for reconstructive surgery in terms of extended anastomoses with or without coronary endarterectomy has doubled in our patients since 1995 and is steadily increasing with 15.7 % (n=102) of these patients requiring such surgery in 2003. Current documentation does not allow any prediction of complex coronary morphology. The Kaplan-Meier survival curve reveals no substantial difference between patients with and without coronary reconstructive surgery up to 8 years after CABG. CONCLUSION: The increase of complexity in CABG procedures currently remains undetected, since preoperative imaging methods often fail to predict complex coronary morphology. Survival after coronary reconstructive surgery is comparable to that of "classical" CABG. Therefore, a standardized documentation is required to evaluate surgical results and to contribute to the improvement of medical decision-making which presupposes valid data.

Aged↗
PubMed1996

First clinical realization of continuous monitoring of liver microcirculation after transplantation by thermodiffusion.

To date, no method is available for the continuous long-term monitoring of liver microcirculation in patients. Experimentally, thermodiffusion has been validated in the quantification of hepatic perfusion. In an attempt to investigate the practicability of thermodiffusion technology in patients after liver transplantation thermodiffusion probes were inserted into the graft in seven patients during liver transplantation. Continuous monitoring started intraoperatively and was performed until day 7, when the probes were extracted transcutaneously. No probe-related complications (i.e., hemorrhage, infection) were observed. In four patients with normal graft function, liver perfusion recovered within 12 h from the intraoperative reduction to a range between 85 and 93 ml/100 g per min. In contrast, primary graft failure (n = 1) was characterized by a constant decrease of hepatic perfusion (< 50 ml/100 g per min). In prolonged reperfusion injury (n = 1), a second peak of transaminases was paralleled by an impairment of liver microcirculation. In one patient, R2 rejection on day 7 was preceded by a drop in hepatic perfusion 48 h earlier. Thus, thermodiffusion is a safe and reliable method for the continuous quantification of liver microcirculation after transplantation in patients. Measurements are reproducible for at least 7 days. Changes in hepatic perfusion during postoperative complications can be detected. The characteristics of microcirculatory disorders will have to be defined in a larger number of patients.

Adolescent↗
PubMed1995

Determination of plasma activities of purine nucleoside phosphorylase by high-performance liquid chromatography: estimates of nonparenchymal cell injury after porcine liver transplantation.

An assay is described for measurement of purine nucleoside phosphorylase (PNP) in plasma by high-performance liquid chromatography (HPLC). A plasma sample was incubated with hypoxanthine and ribose-1-phosphate in phosphate-free medium at pH 7.4 to catalyse the production of inosine by plasmatic PNP. The reaction was stopped by addition of perchloric acid to inactivate the enzyme and to precipitate plasma proteins. After centrifugation and neutralization of the supernatant with NaOH the increase in the substrate inosine was determined by HPLC. Plasma activities of PNP averaged 5.0 mU/ml before and 12.3 mU/ml (p < 0.001), 5 min after porcine liver transplantation. At the same time points, the plasma activities of the frequently used liver enzymes lactate dehydrogenase or alanine aminotransferase remained virtually unchanged. Thus, plasmatic activities of PNP may be a suitable and early indicator of ischemic alterations to the graft in vivo.

Alanine Transaminase↗
PubMed1994

Diagnosis and differential diagnosis of ulcerative colitis and Crohn's disease by hydrocolonic sonography.

OBJECTIVES: The entire length of the colon, starting at the rectosigmoid junction and ending at the cecum, can be visualized by transabdominal sonography after retrograde water instillation into the colon. By this method, termed hydrocolonic sonography, it is possible to evaluate in detail the lumen, the colon wall, and the surrounding tissue. Five layers of different echogenicity can be differentiated within the colon wall. METHODS: In a prospective study of 440 patients, we compared the value of conventional abdominal sonography and hydrocolonic sonography with that of colonoscopy, in the diagnosis and differential diagnosis of ulcerative colitis and colonic Crohn's disease. RESULTS: In 93% of patients with Crohn's disease, the normal five-layer structure of the colonic wall was no longer in evidence, and the wall appeared hypoechogenic and clearly thickened. In contrast, in patients with ulcerative colitis, the five-layer structure could clearly be discerned, and although the colon wall remained hypoechogenic, it was only moderately thickened. Colonic Crohn's disease and ulcerative colitis were detectable by hydrocolonic sonography, with a sensitivity of 96% and 91%, respectively, whereas the sensitivity achieved by conventional abdominal sonography was only 71% and 62%, respectively. Furthermore, hydrocolonic sonography made possible the differentiation of Crohn's disease from ulcerative colitis in 93% of the cases. CONCLUSION: This new diagnostic procedure could thus advantageously be introduced for the diagnosis, differential diagnosis, and follow-up of patients with chronic inflammatory large bowel diseases.

Abdomen↗
PubMed1993

[The diagnosis and differential diagnosis of Crohn's disease and ulcerative colitis by hydrocolonic sonography].

As part of a prospective study the value of hydrocolonic sonography in the diagnosis and differential diagnosis of Crohn's disease (CD) and ulcerative colitis (UC) was assessed and compared with that of coloscopy as standard reference. Of 440 patients who were examined, 41 (23 men, 18 women; mean age 25 +/- 6 years) had CD and 36 (20 men, 16 women; mean age 32 +/- 8 years) had UC. CD and UC were correctly diagnosed by hydrocolonic sonography in 39 and 33 cases, respectively (sensitivity 95 and 91%, specificity 100 and 99%, respectively). Among healthy subjects five layers of variable echo density were demonstrated in the intestinal wall, while in all those with CD the wall was clearly thickened and in 36 of them the wall structure was also abnormal. In 16 patients the wall structure was homogeneous without evidence of layers and in 20, layers 1-3 were not demonstrable and layers 4 and 5 only rudimentary. In contrast, the 33 patients with UC diagnosed by hydrocolonic sonography had only slight thickening of the intestinal wall and all layers were present in 30 of them. CD and UC were correctly distinguished in 91%. Hydrocolonic sonography makes it possible to demonstrate in detail the structural changes in the intestinal wall in CD and UC so that the two conditions can be distinguished.

Adult↗
PubMed1992

Effect of age and gender on in vivo ethanol elimination, hepatic alcohol dehydrogenase activity, and NAD+ availability in F344 rats.

It has been reported that aging strikingly decreases in vivo ethanol metabolism in F344 rats without major effects on hepatic alcohol dehydrogenase (ADH) activity. Because hepatic ADH activity is not always rate limiting in the oxidation of ethanol, we measured in vivo ethanol elimination rate (EER), hepatic ADH activity, and the hepatic-cytoplasmic and mitochondrial redox states after acute ethanol application in 2- and 12-month-old F344 rats of both sexes. In male, but not in female, animals EER decreased with age significantly, by 28% (P less than 0.01). The body-to-liver weight ratio was significantly increased in male (39.4 +/- 1.5 vs 46.5 +/- 2.0; P less than 0.05), but not in female, animals with age. Specific activity of ADH was not significantly changed by age, while the activity was significantly reduced with age in male, but not female, rats when related to body weight (5.1 +/- 0.4 vs 3.9 +/- 0.3 mumoles/100 g b.wt./min; P less than 0.05). The cytoplasmic, but not the mitochondrial (NAD+) to (NADH), ratio was significantly decreased with age in male livers (317 +/- 48 vs 793 +/- 128, P less than 0.05), while this was not the case in female livers. In summary, the data show a sex dependence of the effect of age on ethanol metabolism. The observed reduction in in vivo EER with age in male animals is due at least in part to an increased body-to-liver weight ratio, decreased hepatic ADH activity, and reduced availability of NAD+, the cofactor of the ADH reaction. The cause of this may be decreased transport of reducing equivalents through the mitochondrial membrane due to a lack of shuttle systems or a change in the physicochemical properties of the mitochondrial membrane, or decreased reutilization of NADH as NADPH resulting from a reduction of microsomal ethanol oxidation with age.

Aging↗
PubMed1980

Enzymological aspects of caffeine demethylation and formaldehyde oxidation by Pseudomonas putida C1.

1) The enzymatic demethylation of caffeine (1,3,7-trimethylxanthine) by Pseudomonas putida C1 was investigated; an inducible enzyme system has been observed. This enzyme shows an optimum pH of about 6.0, and the optimum temperature is in the range of 22-24 degrees C. The enzyme is absolutely dependent on NADH or NADPH as a cosubstrate and is activated by CO2+. 2) The formaldehyde generated by the demethylation of caffeine is oxidized by an NAD-dependent formaldehyde dehydrogenase, which is independent of Mg2+ and glutathione. The enzyme was purified from cell-free extracts of Pseudomonas putida C1 by DEAE-cellulose, Sephadex G-150 and Sephadex A-50 chromatography. The purified enzyme was homogeneous as judged by polyacrylamide gel electrophoresis and was most active at a pH between 8.5 and 9.0. The molecular weight was estimated to be about 250,000 by the gel filtration method. Kinetic analysis gave KM values of about 0.2 mM for formaldehyde and 0.5 mM for NAD+.

Aldehyde Oxidoreductases↗