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Biomedical subjects

B Meier

Publications and source records attributed to B Meier.

At least 289 records · Page 16Linked to original sources
PubMed1993

Ethophysiological responses to overwinter food shortage in wild European rabbits.

Wild European rabbits studied under seminatural conditions turned out to have about 30% lower heart rates during periods of overwinter food shortage than during periods with access to green forage or pelleted rabbit chow. Concomitant changes in the animals' metabolic rate (ADMR), body weight, blood sugar level, and foraging activity clearly indicate that this heart rate reduction is a sign of starvation due to insufficient food quality. Telemetered body temperature, on the other hand, was amazingly stable in most subjects, even during overwinter food shortage. These data are discussed with respect to nutritional requirements and possible mechanisms of energy conservation in wild European rabbits.

Acclimatization↗
PubMed1993

Implications of coronary angiography in patients with suspected or known coronary artery disease.

The study analyzes the incidence of coronary lesions and their implications on the treatment offered in 500 consecutive non-selected patients (406 males (81%), age 60 +/- 10 (+/- 1 standard deviation), range 21-88 years) undergoing coronary angiography for suspicion or confirmation of coronary artery disease (excluding patients with congenital and pure valve disease, or cardiomyopathy). A history of myocardial infarction was present in 205 patients (41%). There were no prior cardiac procedures in 334 patients (67%). There was prior coronary angioplasty in 82 patients (16%), coronary artery bypass grafting in 44 (9%) and both in 4 (1%). A total of 36 patients (7%) had had prior coronary angiography only. Mean left ventricular ejection fraction was 61 +/- 12 (18-83%) and mean left ventricular end diastolic pressure was 12 +/- 6 (2-37) mmHg. Angiographically normal coronary arteries were present in 61 patients (12%) and non-significant coronary lesions in 70 patients (14%). One vessel disease was present in 169 patients (34%), two vessel disease in 97 (19%), three vessel disease in 88 (18%) and left main coronary artery disease in 15 (3%). In single vessel disease, involvement of the left anterior descending coronary artery was seen in 82 patients (49%), left circumflex coronary artery in 38 (22%) and right coronary artery in 49 (29%). In two vessel disease, involvement of the left anterior descending coronary artery and left circumflex coronary artery was present in 30 patients (31%), left anterior descending coronary artery and right coronary artery in 36 (37%) and left circumflex coronary artery and right coronary artery in 31 (32%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Conventional coronary angioplasty.

Coronary angioplasty has come a long way since its inception 16 years ago. Although several new devices have shown promise, none, with the exception of the stent, has significantly changed results, and the "simple" balloon remains the backbone of coronary angioplasty. Increased operator experience and advanced guidewire and balloon technology have expanded indications for the procedure to include multivessel angioplasty, angioplasty of chronic occlusions and grafts, angioplasty in the setting of acute myocardial infarction, and supported, high-risk angioplasty. However, single-vessel angioplasty remains by far the most common form of this procedure. Restenosis continues to be an unsolved problem. Results of several trials comparing angioplasty and surgery are expected soon, but they will not answer the question of which method of revascularization is best for the individual patient.

Angioplasty, Balloon, Coronary↗
PubMed1993

Production of oxygen radicals by fibroblasts and neutrophils from a patient with x-linked chronic granulomatous disease.

Recently, a superoxide-generating NADPH-oxidase system in human fibroblasts has been described. Therefore, we reassessed the possible use of this cell type for prenatal diagnosis of CGD patients comparing normal and CGD peripheral blood neutrophils (PMN) and skin fibroblasts in their reactive oxygen intermediate (ROI)-producing capacity. While PMN of the CGD patient showed a clearly reduced respiratory burst activity, which correlated well with the measured content of cytochrome b558, fibroblasts of the same individual showed no impaired production of superoxide anion or H2O2 upon stimulation by cytokines (TNF and IL-1) or other agents (Ca2+ ionophores and PAF, unpublished results). Furthermore, fibroblasts of the CGD patient or of normal donors could be inhibited in ROI production by diphenylene iodonium (DPI) and 2-iodobiphenyl. In contrast to PMN, no inhibition of the fibroblast NADPH-oxidase system was observed using staurosporin, an inhibitor of proteinkinase C. These data demonstrate, in contrast to previous studies, that fibroblasts are able to produce ROI. Nevertheless, since fibroblasts obtained from a CGD patient exhibited no difference in ROI production compared with fibroblasts obtained from healthy donors, they are not suitable for prenatal diagnosis of CGD.

Calcimycin↗
PubMed1993

Early stress tests after successful coronary angioplasty.

The aim of this study was to determine feasibility, safety and yield of early stress tests after successful coronary angioplasty. In 351 consecutive patients with an early stress test performed within 3 days after successful coronary angioplasty, no cardiac or puncture site complications occurred. Seventeen percent of the stress tests remained positive after successful coronary angioplasty. An angiographic explanation, based on the data collected at the time of the angioplasty procedure, was present in 82% of the cases. Positive early stress tests typically only prompted modifications of the drug regimen.

Angioplasty, Balloon, Coronary↗
PubMed1992

Success with coronary angioplasty as seen at demonstrations of procedure.

To assess the real-life results of coronary angioplasty, unidentified participants made notes on 104 cases demonstrated live at twelve international angioplasty courses in 1991. The initially planned procedure was successful in 73% with crossover to another device in 20% for an ultimate success rate of 93%. Interventions lasted an hour on average and two devices on average were used per artery tackled. Rates of success and of complication necessitating reintervention were, for balloon angioplasty (57 cases) 81% and 19%, for directional atherectomy (16 cases) 75% and 0%, for the Rotablator (12 cases) 42% and 42%, for stent implantation (10 cases) 100% and 0%, for excimer laser angioplasty (6 cases) 17% and 33%, and for Rotacs recanalisation (3 cases) 67% and 0%, respectively. The complications were occlusions (threatened, acute, or delayed) and they were usually treated by balloon angioplasty or a stent. No death or myocardial infarction was reported. The observer attending the demonstration tended to take a less favourable view of the outcome than the clinician doing the procedure and in general the results of coronary angioplasty seemed inferior to those reported in journals. Interventions done before an audience will be unusually stressful but this will be outweighed by the fact that difficult cases with a low probability of success are rarely tackled during live courses. This survey suggests that conventional balloon angioplasty, complemented by stent implantation in selected cases, is the treatment of choice.

Adult↗
PubMed1992

Surgical standby for coronary balloon angioplasty.

OBJECTIVE: To assess the predictability of need for emergency surgery after coronary balloon angioplasty. DESIGN: Nonrandomized intervention study. SETTING: Nonprofit university hospital. PATIENTS: Prior to balloon angioplasty, 1000 consecutive patients were assigned to either the "standby" group (189 patients [19%]) or the "no-standby" group (811 patients [81%]). Patients in the standby group (intervention coordinated with cardiac surgery) included all operable patients undergoing angioplasty of their largest coronary arteries that were not currently or previously totally occluded or collateralized; the no-standby group consisted of the remainder of patients. INTERVENTION: Allocation to coronary angioplasty with or without surgical standby. MAIN OUTCOME MEASURES: Need for bypass surgery, occurrence of myocardial infarction, and mortality from complications of angioplasty. RESULTS: Bypass surgery immediately after angioplasty was done in one patient in each group (standby, 0.5%, vs no-standby, 0.1%). The frequency of infarction was 5% vs 4%, respectively. All eight deaths occurred in the no-standby group (1.0%), but none of them were consequences of a lack of surgical standby. They occurred in situations in which bypass surgery would not have changed the outcome (two cardiac failures late after technically successful angioplasty for postinfarct cardiogenic shock, one in-laboratory rupture of an unrecognized ventricular pseudoaneurysm, and one protamine reaction), secondary to acute problems late after successful angioplasty (two sudden deaths and one vessel occlusion in an inoperable patient), or despite surgery (one patient with left main stem dissection). CONCLUSIONS: Performing roughly 80% of coronary angioplasties without surgical standby did not increase patient risk. Coronary angioplasty without surgical backup, albeit not an ideal setting, appears ethically feasible in selected patients if dictated by logistic considerations.

Adult↗
PubMed1992

Dithiocarbamates as potent inhibitors of nuclear factor kappa B activation in intact cells.

Dithiocarbamates and iron chelators were recently considered for the treatment of AIDS and neurodegenerative diseases. In this study, we show that dithiocarbamates and metal chelators can potently block the activation of nuclear factor kappa B (NF-kappa B), a transcription factor involved in human immunodeficiency virus type 1 (HIV-1) expression, signaling, and immediate early gene activation during inflammatory processes. Using cell cultures, the pyrrolidine derivative of dithiocarbamate (PDTC) was investigated in detail. Micromolar amounts of PDTC reversibly suppressed the release of the inhibitory subunit I kappa B from the latent cytoplasmic form of NF-kappa B in cells treated with phorbol ester, interleukin 1, and tumor necrosis factor alpha. Other DNA binding activities and the induction of AP-1 by phorbol ester were not affected. The antioxidant PDTC also blocked the activation of NF-kappa B by bacterial lipopolysaccharide (LPS), suggesting a role of oxygen radicals in the intracellular signaling of LPS. This idea was supported by demonstrating that treatment of pre-B and B cells with LPS induced the production of O2- and H2O2. PDTC prevented specifically the kappa B-dependent transactivation of reporter genes under the control of the HIV-1 long terminal repeat and simian virus 40 enhancer. The results from this study lend further support to the idea that oxygen radicals play an important role in the activation of NF-kappa B and HIV-1.

Base Sequence↗
PubMed1992

[Heterosexual transmission of hepatitis-C virus].

Parenteral transmission of hepatitis C virus (HCV) through blood transfusions and intravenous drug misuse is well established. Since 50% of patients with hepatitis C have no history of parenteral exposure, other ways of transmission must exist. The purpose of this study was to examine the epidemiological importance of heterosexual intercourse for transmission of HCV infection. 29 heterosexual contacts (13 men, 16 women, mean age 47 years) of 29 index patients (16 men, 13 women, mean age 49 years) with histologically und serologically documented chronic hepatitis C were questioned about parenteral exposure and sexual behaviour. Their serum samples were examined for ALT activity and anti-HCV antibodies (first-generation Ortho-HCV-ELISA). Five contacts were using condoms to prevent infection. Five of 24 contacts (21%) practising unprotected sexual intercourse, but none of 5 contacts using condoms, showed evidence of heterosexual HCV transmission: 4 were anti-HCV positive (one with elevated ALT activity) and another showed elevated ALT activity with a negative anti-HCV test. None of these contacts had a history of parenteral exposure. Our results indicate that heterosexual transmission of HCV is epidemiologically important. The true rate of infection may be even higher, for two reasons: (1) not every HCV infection is detected by the anti-HCV test, and (2) the anti-HCV test may turn negative again in uncomplicated infection.

Adult↗
PubMed1992

[Cardiac interventions in Switzerland].

The activity of the working group PTCA and Fibrinolysis of the Swiss Society of Cardiology from spring 1990 to spring 1991 is reported. It included a survey of fibrinolysis for acute myocardial infarction, therapeutic cardiac catheter interventions, and heart operations in Switzerland in 1990. Of the 6096 patients admitted for acute infarction to the participating hospitals, 1768 (29%) underwent fibrinolysis. The number of coronary angiograms performed was 12,501, a 10% increase over the previous year. One third were performed in private hospitals. The number of coronary angioplasties (PTCA) was 2323, a 20% increase. Every fourth PTCA was done in a private hospital. The percentage of PTCAs to coronary angiograms varied from 3 to 35%. There was no correlation to the percentage of multivessel PTCAs. This indicates earlier diagnosis of coronary disease (single vessel disease) in hospitals with increased PTCA activity. The number of bypass operations was 3471. Although the overall figure was higher than that of PTCA, this ratio was balanced or inversed in 3 university hospitals. As for new techniques of interventional cardiology, 24 stents were implanted and 10 atherectomies performed. Moreover, there were 39 valvuloplasties (8 aortic, 20 mitral, and 11 pulmonary), 5 closures of the patent ductus arteriosus, and 24 interventions for arrhythmia (pacemakers excluded). The noncoronary heart operations comprised 694 aortic, 292 mitral, and 100 aorto-mitral operations, 523 operations for congenital or acquired defects, 38 operations for arrhythmia, and 42 transplantations. The development of surgical and nonsurgical cardiac interventions in recent years is characterized by increasing dominance of PTCA in comparison to bypass surgery in most university hospitals.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1992

Relation of the site of acute myocardial infarction to the most severe coronary arterial stenosis at prior angiography.

To determine whether the site of acute myocardial infarction (AMI) can be predicted on the basis of a previous coronary angiogram, 184 consecutive angiograms obtained between March 1972 and August 1990 in 92 patients who had undergone coronary angiography both before and after AMI without intervening bypass surgery or angioplasty were evaluated. Median time between the first coronary angiography and AMI was 26 months (range 1 to 144). On the first angiogram, most patients (89%) had 1- or 2-vessel disease, and 56 (61%) had an abnormal ventriculography. Seventy-two segments (78%) responsible for a future AMI were not significantly stenosed. On the second angiogram, AMI was related to the previously most stenotic segments in only 29 patients (32%). For these patients, median time between first coronary angiography and AMI was slightly shorter (22 vs 28 months; p = 0.04). The severity of the narrowing on the first angiogram was a poor predictor of subsequent AMI. It is concluded that in a selected, medically treated cohort, AMI is frequently related to a segment that was not the most stenotic one or was not even significantly stenosed at previous angiography, particularly with a long interval between the first angiogram and AMI.

Aged↗
PubMed1992

[Second generation hepatitis-C virus test and polymerase chain reaction in anti-C 100 negative patients with chronic non-A, non-B hepatitis].

The aim of our study was to evaluate whether a negative HCV test of the first generation (HCV-ELISA 1) using the antigen C100-3 excludes chronic HCV infection, or whether patients exist who are negative for antibodies to C100-3 in spite of chronic hepatitis C. 27 patients with histologically proven chronic non-A, non-B hepatitis, all of whom were HCV-ELISA 1 negative, were tested by the HCV test systems of the second generation (Ortho-HCV-ELISA 2 and Chiron-HCV-RIBA 2) based on the distinct HCV antigens 5-1-1, C100-3, C33c and C22-3. To determine the presence of viremia, serum samples were also tested for HCV-RNA with "nested" PCR. 10 of 27 patients proved to be persistently negative when tested with the second generation assays. One patient showed low grade reactivity by HCV-ELISA 2, but non-reactivity by HCV-RIBA 2. In none of these 11 patients was HCV-RNA detected. 16 (60%) of 27 patients negative with HCV-ELISA 1 were positive with HCV-ELISA 2. HCV-RIBA 2 detected antibodies to the structural core antigen C22-3 in all of these 16 patients and antibodies to the non-structural antigen C33c in 14 of them, while antibodies to 5-1-1 or C100-3 were not found in any of these cases. 10 (63%) of the 16 HCV-ELISA 1 negative, but HCV-ELISA 2 and HCV-RIBA 2 positive patients were positive for HCV-RNA by "nested" PCR.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Quantitative angiographic follow-up of the coronary Wallstent in native vessels and bypass grafts (European experience--March 1986 to March 1990).

The coronary stent has been investigated as an adjunct to percutaneous transluminal coronary angioplasty to obviate the problems of early occlusion and late restenosis. From March 1986 to March 1990, 265 patients (308 lesions) were implanted with the coronary Wallstent in 6 European centers. For this study, the patients were analyzed according to date of implantation (group 1, March 1986 to January 1988; group 2, February 1988 to March 1990) and vessel type (native arteries versus bypass grafts). Quantitative angiographic follow-up was performed in 82% of the study patients. The early in-hospital occlusion rate in the overall group was 15%. Group 1 patients had a 20% rate in contrast to 12% rate in group 2 (p = not significant [NS]). The early occlusion rate in native vessels and bypass grafts was 19 and 8%, respectively (p = 0.019). Restenosis was determined by 2 criteria (criterion 1, greater than or equal to 0.72 mm loss in minimal luminal diameter from poststent to follow-up; criterion 2, greater than or equal to 50% diameter stenosis at follow-up) within the stent and in the segments immediately proximal and distal to the stent. The restenosis rate with criterion 1 was 43% in the overall group of patients, 35% in group 1 versus 49% in group 2 (p = NS), and 34% in native vessels versus 54% in bypass grafts (p = 0.016). The second criterion was met by 27% of patients in the overall group, 21% in group 1 versus 32% in group 2 (p = NS), and 18% in native vessel versus 39% in bypass grafts (p = 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1992

[Hepatitis-C virus and hepatoma].

To clarify the relationship between hepatitis C virus (HCV) infection and hepatocellular carcinoma (HCC), frozen serum samples from 213 patients with histologically proven liver cirrhosis alone (96 alcoholics, 59 HBsAg positive, 29 non-A, non-B hepatitis, 29 cryptogenic) and 40 patients with liver cirrhosis and HCC (12 alcoholics, 7 HBsAg positive, 7 non-A, non-B hepatitis, 14 cryptogenic) were analyzed for antibodies to hepatitis C virus (anti-HCV) with the ortho-HCV-ELISA. The results were as follows. 50 of 253 (20%) patients were anti-HCV positive. The prevalence of anti-HCV was significantly higher in patients with HCC than in patients without HCC (14 of 40 [35%] vs 36 of 213 [17%]; p less than 0.001). In anti-HCV-positive patients HCC were significantly more frequent than in anti-HCV-negative patients (14 of 50 [28%] vs 26 of 203 [13%]; p less than 0.001). The significantly higher occurrence of HCC in anti-HCV-positive patients was not related to other known risk factors such as alcoholism or chronic hepatitis B virus (HBV) infection. Patients with HCV infection as the only risk factor also had a significantly higher occurrence of HCC (12 of 38 [32%] vs 26 of 203 [13%]; p less than 0.001). Our data suggest that chronic HCV infection plays an important role in the pathogenesis of HCC, in particular in patients with cirrhosis unrelated to alcohol or HBV infection.

Aged↗
PubMed1992

[Anti-HCV test in patients with chronic non-A, non-B hepatitis].

Our study was designed to evaluate the clinical significance of the ELISA-anti-HCV test. 90 patients with histologically proven chronic non-A, non-B hepatitis (NANBH) and a control group consisting of 36 patients with primary biliary cirrhosis (PBC) were analyzed for antibodies to hepatitis C virus (anti-HCV). Frozen serum samples were tested with the ortho-HCV-ELISA. 67 of 90 (74%) patients with chronic NANBH showed antibodies to the hepatitis C virus. The prevalence of anti-HCV in patients with parenterally transmitted and sporadic chronic NANBH was 70% (23 of 33) and 77% (44 of 57) and in patients with chronic active and chronic persistent NANBH 73% (27 of 37) and 76% (40 of 53) respectively. No significant difference in the prevalence of anti-HCV in the 4 subgroups of patients with chronic NANBH was found. 2 of 36 patients (6%) with PBC were anti-HCV positive without evidence of previous HCV infection. Our results bear out the experience of other authors, that HCV is the commonest pathogen of chronic NANBH. The low prevalence of anti-HCV in patients with PBC suggests good specificity. There have been reports in the literature of "false positive results", particularly in autoimmune hepatitis, and it has been shown that borderline positive test results are often unspecific and therefore to be interpreted with care.

Adult↗