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Biomedical subjects

H Drexler

Publications and source records attributed to H Drexler.

At least 235 records · Page 13Linked to original sources
PubMed1986

Coronary thrombolysis during acute myocardial infarction by intravenous BRL 26921, a new anisoylated plasminogen-streptokinase activator complex.

The safety and fibrinolytic efficacy of a new anisoylated plasminogen-streptokinase activator complex (APSAC) was tested in 50 patients with acute myocardial infarction (AMI) less than 4 hours in duration. APSAC (30 mg) was given intravenously as a bolus injection 151 +/- 47 minutes after clinical symptoms. Coronary angiography was then performed to assess coronary artery patency: 28 patients had an inferior AMI and 22 an anterior AMI. A patent infarct-related artery was found in 32 patients (64%) on first coronary angiography 66 +/- 21 minutes after administration of APSAC. Subsequent reperfusion was observed in 10 patients after 74 +/- 16 minutes (84%). Bleeding complications or hematomas were observed in 18 patients, of whom 3 required blood transfusions. Marked hypofibrinogenemia was observed within 24 hours in most patients. A control coronary angiogram was recorded in 37 patients (74%) after 25 +/- 19 days and showed reocclusion in 5 patients.

Adult↗
PubMed1986

T1 pip: a mutant which affects packaging initiation and processive packaging of T1 DNA.

The pip mutation of phage T1 is located between the tar (gene 2.5) and am6 (gene 3) mutations in the region of the T1 genome which codes for early functions. The tar and pip mutations are additive in increasing the efficiency of transduction by T1. When T1 carries the pip mutation the initiation of DNA packaging by the phage at the non-T1, esp-lambda site is more efficient than when the phage is pip+; the small average burst size of 8 to 10 by T1pip suggests that pip causes a reduction in the efficiency with which T1 utilizes pac, the normal packaging initiation site of the phage. The presence of the BglII-D fragment (cut at one end at pac and the other by BglII) after digestion of T1pip DNA by BglII shows that T1pip continues to initiate DNA packaging at pac. The increased molarity of BglII-D coupled with the absence of the BglII-C fragment (which contains DNA on both sides of pac and can only be cut from processively packaged genomes) shows that T1pip packages only genomes which are initiated at pac and is defective in processive packaging.

Bacterial Proteins↗
PubMed1986

Virulence mechanisms associated with clinical isolates of non-O1 Vibrio cholerae.

Twenty one isolates of non-O1 V. cholerae from patients with diarrheal illness were examined for the presence of potential virulence mechanisms. The motile strains (90%) produced cell-associated mannose-sensitive hemagglutinins which reacted with human group O, chicken, sheep and rabbit erythrocytes. Motile isolates also attached to embryonic intestinal epithelial cells (ATCC 407), and the adherence was not inhibited by the presence of 1% D-mannose. All vibrio isolates hemolyzed sheep erythrocytes. Three vibrio isolates (14%) harbored two or three plasmids which ranged in size between 1.7 and 5.2 megadaltons. The presence of the plasmid did not correlate with the presence of hemolysin, hemagglutinins, adhesions or antibiotic resistance in any of the isolates. Thus, it appears that multiple factors associated with bacterial cell surfaces influence adhesin and apparently pathogenic potential of the non-O1 vibrio isolates in the host intestine.

Adhesiveness↗
PubMed1986

Regional vascular adjustments during recovery from myocardial infarction in rats.

Left ventricular function and systemic regional blood flow (radioactive microspheres, 15 +/- 5 mu) were studied 1, 3, 10 or 42 days after left coronary occlusion in conscious rats. One day after coronary occlusion, vascular resistance in the skeletal muscle and cutaneous beds increased while stroke work and left ventricular systolic pressure were depressed. Regional blood flow and hemodynamic data were similar for sham and infarction groups at 3 and 10 days after surgery, except for left ventricular end-diastolic pressure, which was significantly increased in rats with infarction (sham versus infarct: 11.5 +/- 1.0 versus 18.4 +/- 3.2 at day 3 and 12.2 +/- 1.4 versus 19.9 +/- 3.2 at day 10) (p less than 0.05). At 42 days after myocardial infarction, manifest heart failure occurred as documented by decreased cardiac output and left ventricular systolic pressure and elevated left ventricular end-diastolic pressure and vascular resistance in the cutaneous, skeletal muscle and renal beds. In a separate group of animals with moderate (33.2 +/- 2% of left ventricle) and large infarctions (45 +/- 1.3% of left ventricle), regional blood flow was compared with the sham group. Rats with a large infarct demonstrated significant (p less than 0.05) reduction in flow to kidney, gut and liver. In rats with a medium sized infarct, only renal blood flow was significantly reduced. It is concluded that in this model of myocardial infarction, early cardiocirculatory depression is followed by a partially compensated state with increased left ventricular end-diastolic pressure and subsequent systemic and regional vasoconstriction which, in turn, may contribute to late deterioration of heart failure.

Animals↗
PubMed1985

[Modification of organ perfusion by calcium blocker and converting enzyme inhibitor in the conscious rat with heart failure].

The present study examined the regional vascular effects (radioactive microspheres) of converting-enzyme inhibition (captopril, 1 mg/kg) and calcium-antagonism (diltiazem, 1 mg/kg) in a rat model of cardiac failure due to large myocardial infarction (n = 18, infarct size 40% of the left ventricle) both at rest and during submaximal treadmill exercise. Diltiazem increased renal, gastrointestinal, coronary and cutaneous blood flow at rest by 29%, 28%, 26% and 37% (p less than 0.05 each) and enhanced skeletal muscle blood flow during exercise by 16% (p less than 0.05). Captopril improved primarily renal and coronary blood flow at rest (by 59% and 23%, respectively, p less than 0.05) and reduced vascular resistance in the gastrointestinal bed by 25% (p less than 0.05) without significant effects in other circulatory beds. We conclude that the regional vascular effects elicited by converting-enzyme inhibition and calcium antagonism differ considerably in this animal model of congestive heart failure and may be clinically important. The favourable regional vascular profile of diltiazem deserves further clinical investigation.

Animals↗
PubMed1985

Effects of diltiazem on cardiac function and regional blood flow at rest and during exercise in a conscious rat preparation of chronic heart failure (myocardial infarction).

The effects of intravenous infusion of diltiazem on regional blood flow (radioactive microspheres), hemodynamics, and maximum rate of oxygen consumption were evaluated in conscious rats with congestive heart failure caused by large myocardial infarction (n = 10, infarct size 41.8% of left ventricle) and compared with data obtained from rats subjected to sham surgical procedures (n = 9). In both groups data were obtained at rest and during submaximal treadmill exercise during alternate infusion of diltiazem and saline. In the group with heart failure, diltiazem increased stroke volume at rest and during exercise (p less than .05), reduced heart rate (p less than .05), and improved cardiac output during exercise (p less than .05) without increasing left ventricular end-diastolic pressure in any of the animals. Blood flow to renal and splanchnic circulations was reduced in the group with heart failure but was increased by diltiazem to values similar to those observed in sham-operated animals. Although skeletal muscle flow during exercise was significantly increased by the drug, maximal rate of oxygen consumption was not, indicating unchanged oxygen availability within working muscle. Thus diltiazem caused redistribution of blood flow to kidney and gut in animals with myocardial infarction and failure, thereby restoring blood flow to circulatory beds known to be impaired in this setting.

Animals↗
PubMed1985

Effects of nisoldipine on cardiocirculatory dynamics and cardiac output distribution in conscious rats at rest and during treadmill exercise.

This study examined the effects of the dihydropyridine derivative nisoldipine (1.6 micrograms/kg/min) on hemodynamics and regional blood flow (radioactive microspheres, 15 +/- 5 microns) in conscious rats at rest and during treadmill exercises (35 feet/min, 5 min). Nisoldipine significantly reduced systemic vascular resistance (-38%) and mean arterial pressure (-17%) and increased heart rate (P less than .05). Skeletal muscle blood flow was increased and vascular resistances in the skeletal muscle, in renal and coronary arteries and in part of the gut circulations were significantly reduced (all P less than .05). Left ventricular end-diastolic pressure was unchanged by the drug both at rest and during exercise. At exercise, nisoldipine significantly increased skeletal muscle blood flow in four of eight skeletal muscle regions investigated; however, the increase in total skeletal muscle flow was less pronounced compared to the changes at rest. The vasodilator effect of nisoldipine in the renal and splanchnic circulations was markedly attenuated by the exercise-induced vasoconstriction in these circulatory beds. We conclude that nisoldipine is a potent vasodilator of skeletal muscle and coronary and renal arteries. It appears to possess highly selective effects on vascular smooth muscle as compared to its direct cardiac effects.

Animals↗
PubMed1984

Multiple simultaneous determinations of hemodynamics and flow distribution in conscious rat.

A method for multiple simultaneous determinations of cardiocirculatory dynamics, regional blood flow, and total cardiac output distribution in the conscious rat preparation is described. The preparation allows for intravenous administration of agents and can be performed on animals either at rest or during treadmill exercise. Instrumentation procedures involve placement of fluid-filled catheters in the left ventricle, right atria, right jugular vein, and caudal artery. Left ventricular pressures are recorded via a modified 4F Millar transducer-tipped manometer containing a 10-cm extension of fluid-filled PE 50 placed into the left ventricle via the right carotid artery. Radionuclide-labeled microspheres (15 +/- 5 mu) are injected into the left ventricle through the fluid-filled PE 50 at selected times for determination of cardiac output and regional blood flows using the caudal artery catheter as the source of the reference blood sample. Details and selected validation data for procedures involving anesthesia, instrumentation, recovery from anesthesia, data gathering, and data analysis are presented. Emphasis is placed on the procedures required for use of the radioactive microsphere technique in this model with special attention given to quality control of the microsphere stock, counting procedures, and computer analysis of these data.

Animals↗
PubMed1984

Initiation by bacteriophage T1 of DNA packaging at a site between the P and Q genes of bacteriophage lambda.

The growth of phage T1 on cells tandemly lysogenic for heteroimmune lambdoid prophages leads to a nonrandom packaging of lambda DNA by T1. A site, called esp-lambda, is located between the P and Q genes of lambda and results in increased packaging to the left by T1. When cloned into pBR322, the esp-lambda site causes a significant increase in transduction of the plasmid by T1. The nin5 deletion inactivates esp-lambda.

Bacteriophage lambda↗
PubMed1984

[The effect of various cutaneously administered nitroglycerin preparations on coronary heart disease].

Sublingually administered nitroglycerin provides marked benefit in the treatment of angina pectoris due to occlusive coronary disease. Because of its brief duration of action, its usefulness as a prophylactic agent is limited. One way to prolong the beneficial effects is cutaneous administration of a nitroglycerin ointment, and the effects and duration of action of three different preparations of topical nitroglycerin on exercise performance have therefore been studied in a double-blind randomized manner in 44 patients with well documented coronary artery disease and stable angina pectoris. 30 mg 2% nitroglycerin ointment((Plantorgan Co.) produced significant improvement in maximal exercise capacity one and six hours after application; concomitantly there was a decrease in the sum of exercise induced ST-segment depression especially one hour, but less markedly six hours, later. 10 mg 2% nitroglycerin ointment (Pohl Boskamp Co.) also produced an increase in maximal exercise tolerance and a reduction in the degree of myocardial ischemia estimated by the magnitude of exercise-induced ST-segment depression one hour after application, but no clear effect could be measured four hours later. 25 mg nitroglycerin in the "transdermal therapeutic system" (Ciba Geigy) produced a significant improvement in maximal exercise capacity and a significant decrease in the sum of exercise-induced ST-segment depression one and five hours after cutaneous application. Side effects were not observed during these studies, and the topical compatibility of the different ointments was good.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗
PubMed1983

Bronchoscopy and bronchography in children. Experience with 110 investigations.

The results of 92 bronchoscopic examinations and 18 bronchograms in infants and children performed during a two-year period were reviewed. Of 62 patients with suspected foreign-body aspiration, the diagnosis was confirmed in 36 (58%); of 18 patients mainly suspected of having congenital anomalies, a positive diagnosis was made in 12 (66%); but of nine patients with lobar atelectasis only two had abnormal findings. In three patients a transbronchial biopsy specimen did not provide diagnostic material. Bronchography for suspected localized bronchiectasis was performed in 11 patients and a positive diagnosis was made in seven. In all seven patients suspected of having congenital anomalies, bronchography provided a definitive diagnosis. There was no mortality and morbidity was minimal but three patients died of their primary disease. Nearly 60% of the investigations yielded abnormal results, but many of the normal findings were of equal clinical value.

Bronchiectasis↗