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Biomedical subjects

G Kober

Publications and source records attributed to G Kober.

At least 163 records · Page 9Linked to original sources
PubMed1984

[Central venous injection of large amounts of contrast media--advantages of a low osmolar contrast medium in experimentally-induced pulmonary hypertension].

Intravenous administration of contrast material is a prerequisite for the imaging of the cardiovascular system with computed tomography and digital subtraction techniques. Fatal side effects after intravenous contrast injection, particularly in patients with pulmonary hypertension, have been reported repeatedly. The object of this study was to compare hemodynamic side effects of a conventional, ionic contrast medium (amidotrizoate; 2.1 osmol/kg) and a modern, non-ionic compound (iopamidol; 0.8 osmol/kg) after intravenous bolus injection (1.5 ml/kg). Experiments were carried out in 10 open-chest dogs with pulmonary normotension and hypertension induced by embolisation. Under control conditions (PPA = 19.9 mm Hg) both contrast media produced marked pulmonary and peripheral vasodilation. Major effects were seen after amidotrizoate (RPULM 60.3%, RPERI 32.1% vs 72.5% and 70.4% of controls). In pulmonary hypertension (PPA = 44.2 mmHg), iopamidol had similar hemodynamic effects compared to control conditions. In contrast, amidotrizoate initially led to a significant increase in pulmonary pressure and resistance (PPA = 118.6%; RPULM = 141.7%) followed by a delayed depression of right ventricular function (dP/dt = 65.3%; PRVED = 180.9%). Resuscitation was required in 3 dogs with pulmonary hypertension after amidotrizoate injection. Because of these unfavorable hemodynamic side effects of the conventional high osmolality contrast medium in animal experiments, it can be expected that modern compounds with low osmolality pruduce smaller side effects during diognostic interventions in patients with pulmonary hypertension.

Animals↗
PubMed1983

[Incidence of recurrence after successful transluminal coronary angioplasty].

From October, 1977 to April, 1983, a total of 500 transluminal coronary angioplasties (TCA) were performed. The acute success rate averaged 71%, in stenoses of the anterior interventricular branch it was 75%. Long-term results were assessed on the basis of clinical findings, functional studies including ergometry, radionuclide ventriculography and thallium scan, revealing a recurrence rate of 13%. Repeat angiography of 213 patients with successful angioplasty indicated a recurrence of 15% (lasting widening of the stenosis less than 20%). All recurrences occurred within the first three months. A second angiogram was performed 12 months after successful angioplasty in 66 patients who three months after the origin TCA had shown no recurrence. In no case was there a reduction in the widened stenosis. The reported recurrence rate is lower than comparable figures in published reports. Possible reasons for this may be the selection of patients, the technique of angioplasty and long-term treatment with acetylsalicylic acid, nitrates and calcium antagonists.

Angioplasty, Balloon↗
PubMed1983

Noninvasive assessment of left ventricular performance following transluminal coronary angioplasty.

We studied 36 patients with successful transluminal coronary angioplasty (group 1) noninvasively using exercise electrocardiography, exercise T1-201 myocardial scintigraphy and equilibrium radionuclide ventriculography before and 3-5 days after the procedure. Six patients who underwent aortocoronary-bypass surgery (group 2) and 10 patients with stable angina pectoris (group 3) served as controls. All patients had arteriographically documented coronary artery disease at least in one major coronary vessel (stenosis greater than or equal to 70%). In group 1, average coronary stenosis was 81.1 +/- 8.4% before dilatation and 44 +/- 13.7% after the procedure (P less than 0.001). Ischemia score in the exercise electrocardiography decreased from 2.4 +/- 2.7 before dilatation to 0.4 +/- 0.8 after the procedure (P less than 0.001). Myocardial perfusion in computerized T1-201 myocardial scintigraphy 5-10 min after exercise expressed as vitality index (the ratio of T1-201 uptake in the ischemic region to the region of maximal uptake in the same image analyzed carefully in the same view in 2 studies) increased from 72.9 +/- 8.4% before dilatation to 79.9 +/- 11.7% after the procedure (P less than 0.001). Ejection fraction at rest increased from 47.2 +/- 9.2% to 51.0 +/- 9.7% (P less than 0.001) and during exercise from 39.9 +/- 10.5% to 49.4 +/- 10.9% (P less than 0.001) before and after the procedure. In group 2, noninvasive studies showed a tendency to improvement after surgery. In group 3 no significant changes were noted. We conclude that transluminal coronary angioplasty improves both coronary perfusion to ischemic areas supplied by critical coronary artery stenoses and left ventricular function, especially during exercise, if luminal diameter is dilated by greater than 20%.

Adult↗
PubMed1983

Quantitative evaluation of exercise T1-201 myocardial scintigraphy before and after transluminal coronary angioplasty. A preliminary report.

Quantitative evaluation of exercise T1-201 myocardial scintigraphy was carried out to determine the effect of transluminal coronary angioplasty (TCA) in 15 patients with critical coronary artery stenoses (greater than or equal to 70%). Thirteen lesions were successfully dilated (reduction in stenosis by more than 30%); two were unsuccessful. Calculated indices from T1-201 myocardial scintigraphy, using a semi-automatic computer image processing system, included washout factor (WF), vitality index (VI) and redistribution factor (RDF). No changes were noted in WF before and after dilatation. The VI increased in successfully dilated patients from 66.3 +/- 8.5% (mean +/- SD) to 77.8 +/- 10.9% (p less than 0.001) in the areas perfused by the vessels containing the lesions. The RDF decreased significantly after dilatation from 4.4 +/- 6.1% to 1.2 +/- 2.8% (p less than 0.05) 1 hour after exercise and from 10.4 +/- 7.5% to 4.1 +/- 4.2% (p less than 0.01) 3-4 hours after exercise. From these results, we conclude that the perfusion of ischemic areas distal to critical coronary artery stenoses improves following successful dilatation. T1-201 myocardial scintigraphy was shown to be very useful in the evaluation of TCA.

Adult↗
PubMed1983

[The diagnostic value of serum C-peptide determination].

C-peptide and insulin serum determinations were performed in 94 glucagon-stimulated diabetics and in 15 healthy persons. A minimal increase of 1.5 ng C-peptide/ml serum after glucagon injection (1 mg i.v.) was found to be a useful parameter for the differentiation of insulin dependent and non-insulin dependent diabetics. The maximal response to glucagon occurred during the first 10 minutes after the injection (blood was drawn at 2-minutes intervals). Serum insulin levels and basal C-peptide concentrations were of no value in predicting insulin-dependency. Basal C-peptide levels were significantly different from control in juvenile insulin dependent diabetics (decrease) only.

Adolescent↗
PubMed1983

[Anti-angina effectiveness of the calcium antagonist nifedipine in relation to coronary involvement].

36 patients with chronic stable or the variant form of angina pectoris were subdivided according to their coronary angiogram into 4 groups: Group A with a single highgrade stenosis in one coronary artery, Groups B, C and D with different patterns of occluded, but collateralized coronary arteries supplying noninfarcted myocardium. All patients underwent multiple exercise step tests before (K) and after randomly assigned crossover treatment with 20 mg nifedipine (N), 20 mg isosorbiddinitrate (I), the combination of both (I + N) and Placebo (P). Peak and mean ischemic ST-segment depression, the occurrence of angina pectoris and heart rate were evaluated. The mean ischemic ST-segment depression decreased significantly after N in group A by -28% (p less than 0.01), but was not significantly altered in the groups B, C and D (B: -12%, C: +7%, D: +2%). After I, mean ST-segment depression decreased significantly in all groups (A: -36%, p less than 0.001; B: -27%, p less than 0.001; C: -22%, p less than 0.01; D: -29%, p less than 0.05). The combination of I + N was not better than I alone. Peak ST-depression and angina pectoris paralleled the results of mean ST-depression. The resting heart rate increased significantly after N only in group A (+9%, p less than 0.01) and increased after I in the groups A, B and C (A: +11%, p less than 0.05; B: +12%, p less than 0.05; C: +12%, p less than 0.01). During exercise, heart rate was not significantly different in any group or after any type of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Diameters of abdominal veins and arteries during nitrate therapy.

The effects of 1.6 mg NTG on the diameter of abdominal veins and arteries were investigated by means of ultrasound tomography in 26 and 28 healthy persons respectively. Fourteen patients served as controls in the venous studies and 28 in the arterial measurements. The diameter of the caval vein decreased in anterior-posterior direction within 5 minutes after nitroglycerin administration by about 22% from 14.2 +/- 4.0 mm to 11.1 +/- 3.3 mm (p less than 0.005). In contrast, the portal vein enlarged by about 27% from 10.3 +/- 1.8 mm to 13.1 +/- 2.3 mm, the superior mesenteric vein by about 12% from 8.2 +/- 1.6 to 9.2 +/- 1.4 mm, and the splenic vein by about 23% from 6.6 +/- 2.3 mm to 8.1 +/- 1.8 mm (p less than 0.001). The superior mesenteric artery and the proper hepatic artery dilated by about 12% from 7.8 +/- 0.9 mm to 8.7 +/- 0.9 mm and from 6.5 +/- 1.0 mm to 7.3 +/- 0.7 mm respectively (p less than 0.001). There was no significant change in the diameter of the abdominal aorta, however. The results show that NTG induces a relaxation of the abdominal veins and of the abdominal arteries of the muscular type. They suggest that the splanchnic veins participate essentially in the therapeutically important venous pooling effect of NTG. The reduced peripheral venous return is made sonographically visible by a collapse of the inferior vena cava. Furthermore, the influence on the windkessel function after administration of NTG seems to be mediated not by the aorta itself, but rather by its large muscular-type branches like the mesenteric and hepatic arteries.

Abdomen↗
PubMed1983

Active and passive coronary vasodilation after intracoronary and sublingual nitroglycerin.

Nitroglycerin is known to dilate epicardial coronary arteries. It is not known, however, to what extend pressure-dependent passive vasoconstrictive effects may counteract active vasodilation. Therefore, repeated coronary angiograms were performed in 100 patients under standardized conditions before (C) and after 0.16 mg nitroglycerin intracoronarily as well as after an additional 1.6 mg nitroglycerin sublingually. Coronary diameters were determined in stenotic and nonstenotic coronary artery branches. Aortic blood pressure and heart rate were monitored continuously. Aortic blood pressure decreased slightly after intracoronary injection from 146/70 mmHg (C) to 142/77 mmHg and decreased markedly after additional sublingual administration to 129/70 mmHg. Heart rate increased from 78 beats/min (C) to 79 beats/min after intracoronary injection and to 81 beats/min after sublingual administration. Diameters in nonobstructed coronary segments increased in proximal (+7%), medial (+10%), and distal (+12%) segments after intracoronary injection; after sublingual administration a more pronounced diameter increase was observed in all segments (proximal +12%, medial +13%, distal +14%). In obstructed coronary arteries, a stenotic dilation of more than 10% was found in 73% (58/80) after intracoronary injection, but only in 50% (40/80) of the patients after sublingual administration of nitroglycerin. The average diameter increase within coronary stenoses in all patients was 24% after intracoronary injection, but only 10% after additional sublingual administration. In conclusions dilation of epicardial coronary arteries occurs in nonstenotic and stenotic segments. In nonstenotic coronary arteries, there are additive vasodilative effects after intracoronary and sublingual nitroglycerin; in coronary stenoses, however, a maximal effect is achieved after intracoronary injection which is diminished after sublingual administration.

Adult↗
PubMed1983

[Diameter changes of epicardial coronary arteries and coronary stenoses after intracoronary application of SIN 1, a molsidomine metabolite].

The vasodilating effects of intracoronary injections of 0.4 mg SIN 1, the active metabolite of molsidomine, on epicardial coronary arteries and coronary stenoses were evaluated in 14 patients with coronary artery disease in a double-blind randomized fashion versus placebo. 9 additional patients with well-definable coronary stenoses received 0.4 mg SIN 1 as well. Diameter changes of nonstenotic coronary arteries in proximal, medial and distal coronary segments as well as changes of the residual luminal diameters within coronary stenoses were determined before (K), immediately after (M1) and 10 minutes after (M2) intracoronary application of SIN 1; in addition, aortic pressure and heart rate were monitored continuously. Aortic pressure and heart rate did not change after SIN 1 or placebo. After SIN 1, the diameter of nonstenotic coronary arteries increased in proximal segments by + 9% (M1) and + 11.7% (M2), in medial segments by + 17.6% (M1) and + 17.6% (M2), in distal segments by + 26.4% (M1) and + 28.8% (M2). Within coronary stenoses, the residual luminal diameters showed a mean increase by 31.5% (M1) and 48.3% (M2). Placebo did not alter coronary diameters significantly. SIN 1 effectively dilates nonstenotic and especially stenotic epicardial coronary arteries, as it is already known for nitrates and calcium-channel blockers. By intracoronary injections, the direct effects on coronary vessels can be detected without interference with systemic effects. The increase in residual luminal diameters within dynamic coronary stenoses after SIN 1 is most likely an important antianginal mechanism also for molsidomine.

Coronary Disease↗
PubMed1983

[Heart rate behavior and the ischemic ST-segment under carteolol hydrochloride. Dose-response relationship and duration of effect].

1. The dose-response relation and duration of action of the beta-blocking agent 5-(3-tert-butylamino-2-hydroxy-propoxy)-3,4-dihydro-2(1H)-quinolinone hydrochloride (carteolol hydrochloride, Endak, Endak mite) were investigated by means of exercise testing under randomized, double-blind conditions in two groups of healthy probands (n = 9 and n = 9, respectively). 2. The effect of 2 mg carteolol p.o. on changes in heart rate, ischemic ST-segment depression, and blood pressure was studied in 10 patients with coronary heart disease using an exercise test performed 2 h after ingestion of the drug. 3. In terms of exercise heart rate, a clear dose-response relation was demonstrated over the range of dosages (1 and 5 mg) employed. Exercise heart rate was reduced by 10% after a single dose of approximately 0.5 mg. The beta-blocking effect of 0.2 mg carteolol, however, remains unconfirmed. A dosage increase from 5 to 25 mg yields only a slight additional effect. The therapeutically attainable maximal reduction in the rise in exercise heart rate should be about 20%. 4. 24 h after a single dose of carteolol, 60-90% of the initial drug effect was still evident. 5. Resting and standing heart rate were not influenced significantly by 1, 2, 5 or 25 mg carteolol. The groups displayed a somewhat variable response. 6. 2 h after intake of 2 mg carteolol, mean ischemic ST-segment depression was reduced by somewhat more than 50%. Blood pressure at rest remained unchanged, whereas the rise in systolic blood pressure during exercise was lowered significantly. 7. In comparison with other beta-blocking agents, carteolol was effective at low dosage levels and retained considerable potency 24 h after ingestion. In many cases, once--daily administration should be adequate to yield a satisfactory clinical response.

Adult↗
PubMed1983

[Influence of cold-stimuli on hemodynamics and coronary diameters. Provocation of coronary artery spasm].

In 32 patients with coronary heart disease the influence of different cold-stimuli on hemodynamic parameters and coronary artery diameter was examined during left heart catheterization. The cold pressor test (CPT) and the cold air inhalation test (CAIT) were applied to 16 patients in random sequence. 16 patients served as control group. Systolic and diastolic blood pressure increased more under CPT (by 15 and 10 mm Hg respectively) than under CAIT (by 10 and 3 mm Hg). Heart rate and left ventricular enddiastolic pressure did not change. Proximal and distal coronary segment diameters showed a slight, not statistically significant increase under cold-stimuli. All 4 patients with a history of angina pectoris at rest developed coronary spasm, some with ischemic ECG changes; spasm and symptoms disappeared spontaneously when the cold-stimulus was withdrawn. Patients with a history of angina pectoris under cold conditions showed no pathological reactions. It is concluded that two different mechanisms may cause angina pectoris under cold-stimuli. First, the oxygen-consuming effect of an increase in blood pressure, and secondly, an immediate coronary vasospastic reaction. The combined use of CPT and CAIT seems to be an effective and safe means of identifying patients with a tendency to coronary artery spasms.

Adult↗
PubMed1982

[Catheter dilatation of coronary vessel stenosis (transluminal coronary angioplasty) Technic, risks, early and late results].

Between October 1977 and June 1982 a total of 300 transluminal angioplasty procedures were performed in Frankfurt. 75% were single vessel, 16% double vessel and 9% triple vessel disease. The approached stenosis was located in the LAD in 69%, the RCA in 20%, RCX in 4%, ACB in 4% and LM in 3%. Emergency surgery was carried out in 4.0%. One female patient died after surgery (0.3%). Two patients experienced a transmural myocardial infarction (0.7%). On average a widening of the approached stenosis from 80-40% was achieved. Success rate (less than or equal to 20% widening) rose from 59% in the first fifty patients to 76% in the last series. Good long-term results were achieved in 87% of the successful procedures.

Angioplasty, Balloon↗
PubMed1982

[Extent of beta-blocking action of S- and R-penbutolol during exercise testing (author's transl)].

The effect of 40 mg penbutolol (pure S-form = laevo penbutolol) and 40 mg isopenbutolol (pure R-form) on heart rate and blood pressure during exercise testing was investigated under double-blind, randomized, placebo-controlled conditions in 9 probands. 1.5 and 5.5 hours after ingestion of 40 mg penbutolol, resting, standing, exercise, and recovery heart rate as well as systolic pressure during exercise displayed a significant decline. Diastolic blood pressure rose slightly 1.5 hours after penbutolol. Isopenbutolol had no significant effect on resting and standing heart rate. 1.5 hours after ingestion, a slight reduction in exercise and recovery heart rate could be confirmed. The decline, however, was significantly lower than that achieved with penbutolol. In comparison with its dextrorotatory isomer, isopenbutolol, penbutolol has an approximately 100-fold more potent effect on exercise heart rate. This is also reflected in the drug's duration of action.

Adult↗
PubMed1982

[Dose-response relationship and duration of action of acebutolol / investigations on heart rate behaviour and ischemic ST-segment depression].

1. The dose-response relationship and duration of action of 3'-acetyl-4'-(2-hydroxy-3-isopropylaminopropyl)-butyranilide (acebutolol, Prent) were determined under double-blind conditions in 9 volunteers using heart rate at rest and during exercise as a test parameter. 2. The effect of 200 mg of acebutolol on ischemic ST-segment depression, heart rate, and blood pressure was investigated in 10 patients with coronary heart disease. 3. Heart rate at rest and while standing was most markedly reduced in the volunteers 3 h following ingestion of acebutolol 300 mg. 100 and 300 mg lowered heart rate during exercise by 9.9 and 18.9%, respectively. No significant additional effect was achieved by increasing the dosage to 500 mg. 4. 24 h after single oral doses of 300 and 500 mg of acebutolol, nearly 50% of the substance's activity was still evident. 5. In patients with coronary heart disease, maximum heart rate during exercise 3 h after oral intake of 200 mg declined by 13%. The heart rate sum during ergometry fell by 11.2%. Systolic blood pressure at rest and during exercise also was lower. 6. A single oral dose of 100-300 mg of acebutolol consistently reduces heart rate during exercise as well as exercise-induced myocardial ischemia. Since the drug remains active over a 24-h period, administration once daily should provide an adequate therapeutic effect in many patients.

Acebutolol↗