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W Klein

Publications and source records attributed to W Klein.

At least 145 records · Page 8Linked to original sources
PubMed1997

[Contractile force and myocardial ischemia--electrical and ionic mechanisms].

In early myocardial ischemia we find several characteristic electrical and ionic alterations, like action potential shortening K(+)-accumulation or contractile failure. Trautwein and Dudel were 1954 the first to discuss action potential shortening as an important characteristic of myocardial ischemia. They already demonstrated that the action potential shortening is due to an enhanced outward current, while recently KATP-channels have been found to play an important role in the context. It has been suggested that contractile failure due to myocardial ischemia is caused by the shortening of action potential duration, reduced cytoplasmic free calcium levels, intracellular acidification, and a rise in inorganic phosphate and Mg. All of these phenomena may be related to the opening of KATP-channels. The different ionic and molecular mechanisms of contractile failure in myocardial ischemia will be discussed in this paper.

Animals↗
PubMed1997

[Ambulatory surgery in the hospital: decision between national health insurance responsibility and personal job security].

The aim of outpatient surgery is to reduce costs in the health service. However, the number of surgeons working in a surgical department is dependent upon the numbers of occupied beds. This creates an existential conflict in which, by reducing the occupancy of beds in order to take on more outpatient cases, surgeons are putting their own jobs on the line. Possible solutions are here discussed.

Ambulatory Surgical Procedures↗
PubMed1996

Prevalence of coronary artery disease in obese versus lean men with angina pectoris and positive exercise stress test.

The present study assesses the extent of coronary artery disease in men with angina pectoris and definite signs of myocardial ischemia in relation to body mass index. Our results demonstrate that exercise-induced myocardial ischemia in the absence of coronary artery disease in men with angina pectoris is more (2.6-fold) frequent in obese than in lean patients.

Angina Pectoris↗
PubMed1996

Effects of lindane on the planktonic community in freshwater microcosms.

Effects of lindane on natural planktonic communities were investigated in aquatic indoor microcosms. Lindane was dosed to eight 300-liter microcosms for 2 weeks, and effects and recovery processes were monitored over 12 weeks. Mean measured water concentrations of lindane during the exposure period were 3, 6, 13, 27, 55, 102, 230, and 455 micrograms/liter. Zooplankton was severely affected by lindane. The most sensitive organisms were nauplii of copepodes which were affected at all treatment levels > or = 6 micrograms/liter during exposure (Days 2-14). Recovery of nauplii abundance was concentration-dependent at concentrations < or = 55 micrograms/liter lindane, whereas at concentrations > or = 102 micrograms/liter recovery was negligible. Cladocera abundance decreased during exposure to > or = 102 micrograms/liter lindane and did not recover to original levels until the end of the study. For phytoplankton, decreased population densities of Chlorophyceae and microalgae ( < 5 microns) were observed at lindane concentrations < or = 55 micrograms/liter, where zooplankton was only temporarily affected. At higher lindane, concentrations ( > or = 102 micrograms/liter) effects on phytoplankton were not clear, as also increases in abundances were observed, probably as a consequence of minimized grazing pressure, due to high zooplankton mortality. Comparison of these results with data obtained in complex outdoor systems demonstrates the practicability and sensitivity of indoor microcosms and emphasizes the importance of long-term testing and assessment of recovery processes for prediction of environmental effects.

Animals↗
PubMed1996

KATP channel opening does not contribute significantly to the vasodilatory effect of SH-group-containing ACE inhibitors.

Angiotensin-converting enzyme (ACE) inhibitors are widely used in the management of hypertension, heart failure, and nephropathy. It has been suggested that ACE inhibitors containing the sulfhydryl group (SH) have an additional effect on KATP channels. To prove this hypothesis, we studied the effects of the SH-containing ACE inhibitors, captopril and zofenopril, on KATP channel opening of bovine coronary arteries and guinea pig thoracic aortas. Bovine coronary arteries were precontracted with the thromboxane A2 analogue, U46619, and guinea pig thoracic aortas were precontracted with phenylephrine and then relaxed with either captopril or zofenopril (n = 8). Inhibition of KATP channel opening with glibenclamide moderately attenuated the zofenopril-induced relaxation of guinea pig thoracic aorta. However, in the bovine coronary arteries, the relaxing effect of both captopril and zofenopril remained uneffected by glibenclamide. In experiments with enalapril (a non SH-containing ACE inhibitor; n = 6) on guinea pig thoracic aortas, no effect on KATP channels could be seen. From our experiments, we conclude that the postulated opening of KATP channels by SH-group-containing ACE inhibitors contributes little to the vasodilation of guinea pig thoracic aortas caused by ACE inhibitors, and that SH groups have no influence upon KATP channels of bovine coronary arteries.

Adenosine Triphosphate↗
PubMed1996

Reversal of Borrelia burgdorferi associated dilated cardiomyopathy by antibiotic treatment?

It is suggested that Borrelia burgdorferi infection could be associated with dilated cardiomyopathy (IDC). Stanek et al. were able to cultivate Borrelia burgdorferi from myocardial biopsy tissue of a patient with longstanding dilated cardiomyopathy. Here we present a study in which we examined the effect of standard antibiotic treatment on the left ventricular ejection fraction (LVEF) in patients with dilated cardiomyopathy associated with Borrelia burgdorferi infection. In this study we assessed the serum (IgG, IgM Elisa) and history of 46 IDC patients with specific regard to Borrelia burgdorferi infection (mean LVEF 30.4 +/- 1.3%, measured by cardiac catheterization and echocardiography with the length-area-volume method). All 46 patients received standard treatment for dilated cardiomyopathy: ACE inhibitors, digitalis, and diuretics. Eleven (24%) patients showed positive serology and a history of Borrelia burgdorferi infection; nine of these also had a typical history of tick bite and erythema chronicum migrans (ECM) and/or other organ involvement, and two had no recollection of tick bite or ECM but showed other Borrelia burgdorferi-associated disorders (neuropathy, oligoarthritis). These 11 patients with Borrelia burgdorferi infection received standard antibiotic treatment with intravenous ceftriaxone 2 g bid for 14 days. Six (55%) recovered completely and showed a normal LVEF after 6 months, three (27%) improved their LVEF, and two (18%) did not improve at all. This amounts to nine (82%) patients with recovery/improvement in the Borrelia burgdorferi group. The 35 patients who did not show positive serology or a history of Borrelia burgdorferi infection did not receive antibiotic treatment. In this group without Borrelia burgdorferi infection 12 (26%), showed recovery/improvement following the standard treatment of dilated cardiomyopathy (see earlier). Our results indicate that Borrelia burgdorferi infection could play a decisive role in the development of dilated cardiomyopathy, especially in a geographical region such as Graz, where Borrelia burgdorferi is endemic. While we are aware of the small number of Borrelia burgdorferi patients in this study, we nevertheless conclude that in a remarkable number of patients with signs of Borrelia burgdorferi infection, dilated cardiomyopathy could be reversed and LVEF improved.

Adolescent↗
PubMed1996

Exercise increases plasma concentrations of (R)- and (S)-propranolol.

OBJECTIVE: We recently reported a highly stereoselective increase in plasma concentrations of (S)-atenolol during exercise which is most likely due to a release of the drug from adrenergic cells. The objective of the present study was to investigate the influence of physical exercise on plasma concentrations of the (R)- and (S)-enantiomers of propranolol. METHODS: Blood samples were taken immediately before and at the end of exercise in 12 patients receiving chronic treatment with racemic (R, S)-propranolol. Plasma concentrations of (R)- and (S)-propranolol were determined by HPLC. RESULTS: In contrast to atenolol, mean plasma concentrations of (S)-propranolol were significantly higher (+20%) than those of (R)-propranolol at rest. During exercise there was an increase in plasma concentrations of both (R)-propranolol (+129%) and (S)-propranolol (+109%). CONCLUSION: Based on information from in vitro studies we conclude that the increase in plasma concentrations of (S)-propranolol during exercise is caused by a release of the drug from adrenergic nerves, whereas the reason for the increase in (R)-propranolol remains to be determined. This release of the beta-adrenoceptor blocking (S)-enantiomer directly at the synaptic gaps might be one reason for the poor correlation between plasma concentration and effect of beta-adrenoceptor antagonists repeatedly described in the literature.

Adrenergic beta-Antagonists↗
PubMed1996

Endoscopy of the deep infrapatellar bursa.

Endoscopy of extraarticular cavities, clefts, and recesses is routinely performed today. Endoscopy of the deep infrapatellar bursa of the knee is an additional new field for minimal invasive exploration and surgery, the more so as this area can be penetrated without major additional tissue damage following arthroscopy of the knee. The indications for endoscopy of the infrapatellar recess are ossicle formation and osteophytes in Osgood Schlatter's disease, infrapatellar tendinopathy, and bursitis. Endoscopic surgery consists in bursa resection, shaving of the backside of the distal patella tendon, and removal of ossicles and osteophytes. In three cases of Osgood Schlatter's disease, the deep infrapatellatendon recess was successfully decompressed by endoscopic methods. The potential danger of this endoscopic procedure is iatrogenic damage of the patella insertion area.

Arthroscopes↗
PubMed1996

Characterization of a cytoplasmic trehalase of Escherichia coli.

Escherichia coli can synthesize trehalose in response to osmotic stress and is able to utilize trehalose as a carbon source. The pathway of trehalose utilization is different at low and high osmolarity. At high osmolarity, a periplasmic trehalase (TreA) is induced that hydrolyzes trehalose in the periplasm to glucose. Glucose is then taken up by the phosphotransferase system. At low osmolarity, trehalose is taken up by a trehalose-specific enzyme II of the phosphotransferase system as trehalose-6-phosphate and then is hydrolyzed to glucose and glucose-6-phosphate. Here we report a novel cytoplasmic trehalase that hydrolyzes trehalose to glucose. treF, the gene encoding this enzyme, was cloned under ara promoter control. The enzyme (TreF) was purified from extracts of an overexpressing strain and characterized biochemically. It is specific for trehalose exhibiting a Km of 1.9 mM and a Vmax of 54 micromol of trehalose hydrolyzed per min per mg of protein. The enzyme is monomeric, exhibits a broad pH optimum at 6.0, and shows no metal dependency. TreF has a molecular weight of 63,703 (549 amino acids) and is highly homologous to TreA. The nonidentical amino acids of TreF are more polar and more acidic than those of TreA. The expression of treF as studied by the expression of a chromosomal treF-lacZ fusion is weakly induced by high osmolarity of the medium and is partially dependent on RpoS, the stationary-phase sigma factor. Mutants producing 17-fold more TreF than does the wild type were isolated.

Amino Acid Sequence↗
PubMed1996

Intracoronary Stent Used in a Transplanted Heart.

The development of occlusive cardiac allograft vasculopathy is different from coronary artery disease in native vessels and treatment is still an unsettled problem. We describe a case of a 53-year-old male who underwent heart transplantation because of severe dilated cardiomyopathy. Based on myocardial ischemia, coronary angiography was performed six years later. Significant two-vessel coronary artery disease had developed and was treated by coronary angioplasty. Due to a suboptimal result, a Palmaz-Schatz stent was successfully implanted in the left anterior descending artery. The patency of the stent was demonstrated by ultrafast computed tomography and confirmed by control angiography three months later.

Journal Article↗
PubMed1996

[Abdominal trauma and pelvic injury in the growth period].

Children with pelvic fractures usually are polytraumatized. Concomitant abdominal and pelvic injuries are not uncommon. Medical records and X-rays of 54 children, in which a pelvic fracture was diagnosed at our institution from 1974-1993, were reviewed. Children ages < or = 16 years and treated as in-patients were included in this study. The fractures were classified according to the AO-Classification. 47 patients (87.0%) had concomitant injuries. The mean Polytrauma Score was 23.7 (mean Injury Severity Score 30.5). Nine Children sustained an open pelvic fracture with rectal and/or vaginal tear. 15 genitourinary lesions were found in 13 children. 18 patients underwent laparotomy. A large pelvic/retroperitoneal hematoma was found in 11 cases. There were 7 liver lacerations, 7 splenic injuries, 2 mesenteric tears, 2 kidney injuries and 1 small bowel lesion. Eight children (14.8%) died with 5 of them due to retroperitoneal or/and abdominal bleeding complications. A recent follow-up examination (81.8%) with a mean follow-up of 11.3 years showed that long-term morbidity usually was attributed to pelvic concomitant injuries.

Adolescent↗
PubMed1996

[Serum digoxin level in patients with dilated cardiomyopathy].

To investigate whether measuring levels of digoxin in patients with idiopathic dilated cardiomyopathy (IDC) is helpful in dose adjustment of digoxin we did the following study. In 77 patients (63 male, 14 female) with invasively verified IDC serum-digoxin levels were measured after a treatment period with beta-acetyldigoxin of at least 6 months. All patients received digoxin, 76 had ACE-inhibitors and 69 used diuretics. Mean serum-levels of digoxin were 0.96 ng/ml while using a mean daily dose of digoxin of 0.24 mg. Those who showed a serum level of digoxin within the recommended range took a slightly higher daily dose of digoxin when compared to those with low levels of digoxin (0.26 vs. 0.23 mg/day, p < 0.05). Therefore, we conclude that low serum-levels of digoxin are mainly caused by low intake of digoxin and it is justified to measure digoxin-levels in IDC-patients even if it increases costs.

Adult↗