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Biomedical subjects

B Meier

Publications and source records attributed to B Meier.

At least 307 records · Page 17Linked to original sources
PubMed1992

Magnum system for routine coronary angioplasty: a randomized study.

The Magnum system, initially designed for coronary angioplasty (PTCA) of chronic total occlusion, consists of a balloon catheter and a solid steel 0.021 inch (0.53 mm) steerable and removable wire with a soft and moldable distal portion, tipped with a 1 mm olive. To evaluate its performance in routine PTCA, 200 unselected consecutive patients were randomized to two equal groups, i.e., group Magnum (100 patients, 115 vessels) and group Standard (100 patients, 118 vessels) including 18 and 21 patients with chronic total occlusions, respectively. Randomization was performed by the sealed envelope system in the catheterization laboratory and crossover of system was imposed if it was not possible to place a balloon correctly within 20 min of fluoroscopy time. There were no significant differences between groups concerning clinical and angiographic baseline characteristics, size of initial balloons (3.0 +/- 0.3 mm in both groups), fluoroscopy time to cross the lesion with the wire (Magnum: 4 +/- 5, Standard: 5 +/- 6 min), total fluoroscopy time (Magnum: 11 +/- 9, Standard: 12 +/- 12 min), and need for crossover (Magnum: 10%, Standard: 16%). Success rates per lesion were comparable with 90% in group Magnum and 84% in group Standard, as were the complications with one inhospital death in group Standard, occurring three weeks after PTCA and stent implantation. There was no emergency operation. Six patients per group had myocardial infarction of whom two in group Magnum and one in group Standard developed a Q-wave. The following variables were significantly in favor of the Magnum system compared with the Standard system: success rate in nontotal lesions (97% versus 90%) crossover success in total occlusions (0 vs. 33%), fluoroscopy time to cross the lesion with the balloon once the wire was in place (1 +/- 2 vs. 2 +/- 4 min), and use of a single versus 1.2 +/- 0.5 wires per lesion. The only advantage of the Standard systems was the more common use of 7 French guiding catheters (Magnum: 40%, Standard: 53%, p = 0.09). The Magnum system compares favorably with standard systems for routine PTCA. The robust design of the Magnum wire does not impair ease of placement and safety but saves material and facilitates balloon advancement across the lesion.

Aged↗
PubMed1992

Coronary and left ventricular pacing as standby in invasive cardiology.

Coronary pacing using as unipolar negative electrode a guidewire placed in a coronary branch was tested in 349 sites of 300 consecutive patients undergoing coronary angioplasty. It was possible for 339 sites (97%). The threshold currents ranged from 1 to 15 (mean +/- standard deviation 3.4 +/- 2.4) mA. Side effects were seen in 13 patients (4%): 6 (2%) had transient coronary spasm, 4 (1%) had diaphragmatic stimulation, and 3 (1%) had stinging pain at the skin electrode. Of the 10 cases with pacing failure, left ventricular pacing was successfully tested in 5 by introducing the coronary wire or another wire into the left ventricle. It yielded a threshold of 2-8 (3.2 +/- 2.7) mA. Therapeutic pacing for significant bradycardia was required in 7 patients (2%). It was successful in all. Coronary or left ventricular pacing appears to be a simple and reliable temporary measure. When there is no wire in the coronary artery or for diagnostic catheterization, left ventricular pacing can be done using the same setup and any type of guidewire.

Angioplasty, Balloon, Coronary↗
PubMed1992

Aortic dissection as complication of percutaneous transluminal coronary angioplasty.

We report two cases of aortic dissection during coronary angioplasty with a disparate evolution that was due to the different location of the entry port of the dissection. Aortic dissection occurring during coronary angioplasty may be self-limiting, but it may also be life-threatening and may call for urgent surgical repair.

Aortic Dissection↗
PubMed1992

Obtaining mutants for protoplast fusion of gibberellin-forming Gibberella fujikuroi strains.

Auxotrophic, drug-resistant, nitrate-nonutilizing, and albino mutants have been isolated in Gibberella fujikuroi following UV mutagenesis. Protoplasts of complementing auxotrophic strains, mutants with resistance markers, or mutants blocked in different steps of the nitrate assimilatory pathway have been fused to form heterokaryons, diploids, or recombinant haploids. The properties of fusant strains, including gibberellic acid productivity, have been examined and compared to parent strains.

Cerulenin↗
PubMed1992

Intracoronary electrocardiogram during coronary angioplasty.

This prospective study examines the data derived from the intracoronary electrocardiogram (ECG) (derived from the coronary guide wire) compared with that from four standard surface leads (I, II, III, and V2) in documenting myocardial ischemia during coronary angioplasty. Intracoronary and surface ECGs were simultaneously recorded in 300 consecutive patients (mean age 59 +/- 10; range 33 to 80 years; 246 males [82%] during coronary angioplasty in 368 lesions (167 left anterior descending [46%], 85 left circumflex [23%], 107 right coronary arteries [29%], and nine bypass grafts [2%]), before balloon inflation, at 1 minute of inflation, and at the end of the procedure. ST segment changes (greater than 0.1 mV) were observed in the intracoronary ECG in 306 lesions (83%) (151 left anterior descending [88%], 75 left circumflex [89%], and 80 right coronary arteries [73%]) versus in 245 lesions (67%) in the surface ECG (126 left anterior descending [73%], 43 left circumflex [47%], and 76 right coronary arteries [70%]; [p less than 0.0001]). The mean ST segment shift was 0.5 +/- 0.4 mV in intracoronary and 0.1 +/- 0.2 mV in standard leads (p less than 0.0001). ST elevation was seen in 97% of cases with intracoronary ECG changes versus in 83% with surface ECG changes. The remainder had ST depression. A total of 48 lesions (13%) did not produce ECG changes and 62 (16%) had silent ischemia. In 75 lesions (21%), ECG changes were seen only in the intracoronary ECG, compared with 14 lesions (4%) with changes only in the surface ECG (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1992

Magnum/Magnarail versus conventional systems for recanalization of chronic total coronary occlusions: a randomized comparison.

The Magnum/Magnarail system consists of "over-the-wire" balloon catheters and a 0.021 inch (0.53 mm) guide wire with a 1 mm olive-shaped tip. To compare it to conventional systems, 100 consecutive unselected patients with chronic total coronary occlusions were randomly assigned to one of two groups. If the balloon could not be placed within 20 minutes of fluoroscopy time with the allocated system, a crossover to the other system was imposed. The Magnum group comprised 50 patients and 52 occlusions, and the conventional group included 50 patients and 51 occlusions. There were no significant differences with regard to the length of the occlusions (Magnum 1.4 +/- 1.3 mm, conventional 1.6 +/- 1.7 mm) or the duration (Magnum 1.4 +/- 1.9 months, conventional 1.4 +/- 1.8 months). The primary success rate before crossover with the Magnum/Magnarail system was 67% versus 45% with conventional systems (p less than 0.05). The Magnum/Magnarail system as a second tool after crossover was successful in 11 of 28 patients (39%) versus 2 of 16 patient (12%) in whom success was achieved with a conventional system as a second tool (p less than 0.05). An increase in the creatine kinase level (more than twice normal) was seen in one patient (2%) in the Magnum/Magnarail group and none in the conventional group. Q wave infarctions were not seen. There was one in-hospital death (2%) in the conventional group. There were no significant differences with regard to the number of guiding and balloon catheters or fluoroscopy time. The Magnum/Magnarail system proved superior to conventional systems for balloon recanalization of chronic total coronary occlusions in terms of higher success rates.

Aged↗
PubMed1992

Limits of thallium-201 exercise scintigraphy to detect coronary disease in patients with complete and permanent bundle branch block: a review of 134 cases.

We reviewed the records of 68 patients with right bundle branch block (RBBB) and 66 patients with left bundle branch block (LBBB), who had undergone thallium-201 exercise scintigraphy and coronary arteriography, to determine the sensitivity, specificity, and positive and negative predictive values of thallium-201 imaging for the detection of coronary artery disease in the presence of intraventricular conduction abnormalities. In patients with RBBB the sensitivity, specificity, and positive and negative predictive values were, respectively, 83%, 89%, 79%, and 92% for the anteroseptal region and 83%, 84%, 83%, and 84% for the inferoposterior region. In patients with LBBB these values were, respectively, 94%, 33%, 36%, and 93% for the anteroseptal region and 77%, 90%, 81%, and 88% for the inferoposterior region. In this second group defects limited to the septal region were a good predictor of false positive scintigrams (9/10 cases), but if apical defects used as the sole criterion for detecting lesions in the left anterior descending artery improved the specificity to 85%, the sensitivity was greatly reduced (35%). We conclude that exercise scintigraphy is a reliable method for detection of coronary lesions in patients with RBBB and in patients with LBBB and inferoposterior perfusion defects, but it is unable to discriminate between normal subjects and patients with coronary disease in the presence of LBBB and anteroseptal perfusion defects. In addition, limited septal defects are highly suggestive of false positive scintigrams in this latter group of patients.

Adult↗
PubMed1992

Stage-specific expression of aldolase isoenzymes in the rodent malaria parasite Plasmodium berghei.

We have cloned two gene (aldo-1 and aldo-2) encoding the glycolytic enzyme aldolase of the rodent malaria parasite Plasmodium berghei. The amino acid sequence of one gene product, ALDO-1, is virtually identical to P. falciparum aldolase whereas ALDO-2, the second gene product, is different and has 13% sequence diversity to ALDO-1. We expressed ALDO-2 as an active enzyme in Escherichia coli and compared the biochemical and kinetic properties to that of P. falciparum recombinant aldolase (ALDO-1 type). Based on the Km and Vmax constants for FMP and FBP, neither ALDO-1 nor ALDO-2 can be clearly assigned to any of the known mammalian isoenzyme classes. We demonstrate that expression of the two isoenzymes is developmentally regulated: specific antibody probes detect ALDO-1 in sporozoite stages of P. berghei and ALDO-2 is found in blood stage parasites.

Amino Acid Sequence↗
PubMed1992

The enzymatic decomposition of salicin and its derivatives obtained from Salicaceae species.

The enzymatic catalysis of the decomposition of Salicaceae phenolic glucosides was tested using almond beta-glucosidase and rabbit and porcine liver esterases. The beta-glucosidase catalyzed the complete hydrolysis of salicin and salicortin, yielding saligenin and glucose. Salicortin also produced (+)-6-hydroxycyclohexen-2-one (6-HCH). The acylglucosides were not decomposed by the beta-glucosidase. Both esterases catalyzed the decomposition of tremulacin, salicortin, and 2'-O-acetylsalicortin, releasing tremuloidin, salicin, and 2'-O-acetylsalicin as the main products, accompanied by 6-HCH and catechol. Tremuloidin and 2'-O-acetylsalicin were quite stable under the esterase hydrolysis, and salicin was not decomposed at all.

Animals↗
PubMed1992

Variation in Growth and Secondary Phenolics Among Field-Cultivated Clones of Salix myrsinifolia.

Nine S. MYRSINIFOLIA clones were studied for secondary phenolics and phytomass production in an old, unfertilized hayfield after the second growing season. S. MYRSINIFOLIA is one of the most promising willow species for the production of herbal drug material. Its salicylate content is moderately high in all parts of the shoot. The leaf and stem phytomass varied significantly among clones, but more than 70% of the total variation could be explained by within-clonal phytomass variation. Similarly, the accumulation of salicin, salicortin, chlorogenic acid (+)-catechin, proanthocyanidins, and unknowns varied significantly according to source (tissue, individual, or clone), and in most cases the environmental (within-clonal) variation was nearly as high as the genetic variation (between-clones). In the selection of the best clones for the production of herbal drug material three main factors should be taken account: costs of cultivation, costs for transportation, and costs for production of extracts. A high phytomass clone may be a low-quality clone as far as salicylates are concerned.

Journal Article↗
PubMed1992

Fatal anaphylactoid response to protamine after percutaneous transluminal coronary angioplasty.

A generalized skin erythema and severe hypotension developed following administration of protamine for the reversal of heparin anticoagulation after an unsuccessful attempt at percutaneous transluminal angioplasty in a patient who had never been exposed to protamines before. Evidence of classical pathway complement activation was present indicating that this reaction could have been triggered by a non-immunological mechanism. The patient could not adequately be resuscitated because of the presence of severe coronary artery disease.

Aged↗
PubMed1992

Abnormal left ventricular filling pattern in patients with single vessel coronary artery disease: effect of angioplasty.

To study the effect of coronary angioplasty (PTCA) on left ventricular (LV) diastolic filling, mitral Doppler flow tracings of 15 patients with isolated stenosis of the left anterior descending coronary artery (LAD) and normal systolic LV function were recorded before PTCA as well as 24 h and 3 months after successful PTCA. Compared to control subjects, patients with LAD stenosis exhibited an abnormal LV filling velocity pattern before PTCA. The day following PTCA, the ratios of the early peak diastolic velocity to the peak late diastolic velocity and of the time velocity integral of the early diastolic filling phase to the time velocity integral of the late diastolic filling phase were unchanged. Despite the absence of clinical evidence of restenosis, LV filling remained abnormal 3 months after PTCA. The results suggest that abnormalities of the LV filling velocity in patients with isolated LAD stenosis and normal systolic function may persist as long as 3 months after PTCA.

Angioplasty, Balloon, Coronary↗