Biomedical subjects

T Wendt

Publications and source records attributed to T Wendt.

At least 55 records · Page 3Linked to original sources

PubMed1992

Acute hemodynamic effects of carvedilol in comparison with propranolol in patients with coronary heart disease.

In a randomized, double-blind study oral doses of 50 mg carvedilol (Dilatrend) were compared with 40 mg propranolol in 16 male patients with coronary heart disease, CHD [12 without significant stenoses following percutaneous transluminal coronary angioplasty (PTCA), 4 with multivessel disease]. Bicycle ergometry in the supine position was performed before and 80 min after drug application; measurements were done at rest, during and after exercise. Clinically, the total exercise time and the onset of angina and exhaustion were noted, while the investigated hemodynamic parameters were heart rate, systemic and pulmonary pressures and resistances, cardiac index, and lower limb blood flow. Clinically, carvedilol improved the exercise tolerance more than propranolol as regards angina and exhaustion. Hemodynamically, carvedilol did not lead, as the classic betablocker propranolol does, to an increase in systemic or pulmonary resistance, to a decrease in cardiac output, or to an increase of the pulmonary capillary wedge pressure during exercise, but instead caused opposite changes. In contrast to propranolol, the post exercise lower limb blood flow had increased significantly. The differences in action between the two betablockers can be explained by the vasodilating properties of carvedilol. Due to these acute effects, carvedilol may be preferred to propranolol in the treatment of CHD patients with hypertension, peripheral occlusive artery disease, and/or coronary vasospasm.

Adrenergic beta-Antagonists↗

PubMed1991

Controlled reperfusion during emergency coronary artery bypass surgery after angioplasty failure restores immediate segmental contractility.

This study tests the hypothesis that careful control of the composition of the initial reperfusate and the conditions of the reperfusion during emergency CABG will restore immediate segmental contractility in the previously ischemia area despite ischemic intervals of greater than 2 hours. Between January 1987, and October 1990, 41 consecutive patients with acute coronary occlusion (90% due to PTCA failures) were reperfused during emergency myocardial revascularization according to one of two different protocols: in 25 patients the reperfusate was normal blood given at systemic pressure ("uncontrolled reperfusion"); in 16 patients the ischemic segment was reperfused during the first 20 minutes with a regional blood cardioplegic solution (substrate-enriched, hyperosmotic, hypocalcemic, alkalotic, diltiazem-containing) at 37 degrees C at a pressure of 50 mmHg. Thereafter, total bypass was prolonged for an additional 30 minutes before extracorporeal circulation was discontinued ("controlled reperfusion"). Assessment of regional contractility (echocardiography, radionuclide ventriculography), electrocardiographic evidence of myocardial infarction, release of CK and CK-MB enzymes, and hospital mortality were performed. Quantification of regional contractility was done with a scoring system from 0 (normokinesis) to 4 (dyskinesis). Data are expressed as mean +/- standard error of the mean. Both groups were well matched for age, sex, and the distribution of the occluded artery. In the controlled reperfusion group there was a higher incidence of previous infarctions (50% vs 30%), additional significant stenosis (1.1 +/- 0.2 vs 0.8 +/- 0.1), and cardiogenic shock (38% vs 20%) as compared to uncontrolled reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗

PubMed1991

Immediate functional benefits after controlled reperfusion during surgical revascularization for acute coronary occlusion.

This study tests the hypothesis that contractile dysfunction that often develops after acute coronary occlusion despite emergency revascularization can be avoided by careful control of the composition of the initial reperfusate and the conditions of the reperfusion. Between January 1987 and May 1989, 31 consecutive patients with acute coronary occlusion (90% resulting from percutaneous transluminal coronary angioplasty failures) were reperfused during emergency myocardial revascularization according to one of two different protocols. In 23 patients the reperfusate was normal blood given at systemic pressure ("uncontrolled reperfusion"); in eight patients the ischemic segment was reperfused during the first 20 minutes with a regional blood cardioplegic solution (substrate-enriched, hyperosmotic, hypocalcemic, alkalotic, diltiazem-containing) at 37 degrees C at a pressure of 50 mm Hg. Thereafter total bypass was prolonged for an additional 30 minutes before extracorporeal circulation was discontinued ("controlled reperfusion"). Assessment of regional contractility (echocardiography, radionuclide ventriculography), electrocardiographic evidence of myocardial infarction, release of creatine kinase and isoenzyme of creatine kinase, and hospital mortality was performed. Regional contractility was quantified with a scoring system from 0 (normokinesis) to 4 (dyskinesis). Data are expressed as mean +/- standard error of the mean. Both groups were well matched for age, sex, and the distribution of the occluded artery. In the controlled-reperfusion group there was a greater prevalence of previous infarctions (63% versus 43%), additional significant stenosis (1.3 +/- 0.2 versus 0.8 +/- 0.2), and cardiogenic shock (38% versus 17%) compared with the uncontrolled-reperfusion group. Furthermore, the interval between coronary occlusion and reperfusion was significantly longer in the controlled-reperfusion group (4.0 +/- 0.5 versus 2.3 +/- 0.3 hr; p less than 0.05). Regional contractility returned to normal in all patients treated by controlled reperfusion (wall motion score = 0.8 +/- 0.3, normokinesis = 0, slight hypokinesis = 1). In contrast, regional contractility remained severely depressed after uncontrolled reperfusion with normal blood (score 2.5 +/- 0.2; p less than 0.05), with only four of 23 patients with a score less than 2 (2 = severe hypokinesis). Postoperatively enzymes and electrocardiographic changes were similar in both groups. One patient died of mitral insufficiency in the controlled-reperfusion group, despite complete recovery of wall motion in the angioplasty-related artery. Conversely, the four of 23 deaths after uncontrolled reperfusion occurred in patients who sustained infarct in the area of the coronary occlusion (mortality 13% versus 17%). In conclusion, these preliminary clinical results indicate that immediate recovery of segmental contractility can be achieved after acute coronary occlusion if the initial reperfusion is controlled.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗

PubMed1991

[Radioactive burden resulting from zirconia implants].

Due to its mechanical properties circonia is an interesting implantation material. However, it may contain a certain amount of radioactive isotopes. The measurement of alpha-emission reveals varying amounts of radiation. As a result, a declaration of radioactivity should be required for circonia implants and only circonia with low emission levels should be used for implantation purposes.

Alpha Particles↗

PubMed1990

[Angioscopy of the coronary vessels].

Direct visual examination of the interior surfaces of intact human coronary arteries is now a reality, both from intraoperative and transluminal approaches. As an additional investigation to angiography it improves the knowledge about the corresponding morphology of angiographically visible changes. Since the first report about percutaneous and intraoperative coronary angioscopy by Spears et al. in 1982 important indications concerning the intraoperative approach were defined such as the control of coronary atherectomy, intraoperative balloon dilatation and laser angioplasty, the inspection of the grafts prior to implantation and the assessment of the quality of the distal anastomosis after graft insertion. The most important clinical result angioscopy has brought about is the postulation of a concept of the different clinical forms of coronary artery disease based on the morphological stages of atherosclerosis, which were defined by angioscopy and could be related to clinical symptoms. Scientific studies today are concerned with determinants for the patency rate of bypasses, the restenosis rate of PTCA, the acute and chronic effects of drugs, and the mechanism of all kinds of catheter-supported angioplasties. The next important application of coronary angioscopy will undoubtedly be the simultaneous visual control of coronary angioplasty procedures such as laser angioplasty and other new methods.

Coronary Artery Disease↗

PubMed1990

Percutaneous transhepatic gallstone dissolution with methyl tert-butyl ether in complicated stone diagnosis and gallbladder anomalies.

In a total of 117 successfully punctured patients with gallbladder stones that were to be treated with methyl tert-butyl ether, 11 showed shell-like structured concrements on the CT scan. In 2 patients, pigment stones and very old concrements were suspected. In these 13 patients solitary stones dissolved in 2.9 hours, multiple stones in 10.8 hours, which corresponds to the treatment time of the total group. In 4 patients we diagnosed cholesterol stones, but dissolution was very slow, suggesting that the stones were covered with pigment. In 21 patients we found marked gallbladder anomalies, such as extreme septation, two-chamber gallbladders, gallbladder diverticula with a wedged stone, or gallbladders in which the fundus was positioned cranially. In these patients puncture time was prolonged by 25%. However, since in all patients the stones dissolved in the same time as in the total group (solitary stones; 3.1 hours: multiple stones: 10.4 hours) and since in 33% there was also sludge in the gallbladder, shape variants of the gallbladder obviously have no influence on the stone type. Whether they induce recurrent stones more often than normal gallbladders cannot be assessed at present. Shape variants of the gallbladder and layered stones on CT scan, however, do not represent a contraindication to MTBE therapy.

Cholecystography↗

PubMed1990

Prolonged abnormalities of LV regional wall motion after normal reperfusion in patients with preoperative cardiogenic shock.

The purpose of this clinical study was to (1) evaluate mortality rates after surgical interventions for patients in cardiogenic shock (CS) secondary to acute coronary occlusion, acute ventricular septal defect (VSD) or acute valvular heart disease, (2) determine the pre-operative regional wall motion, and (3) ascertain the recovery of preoperative regional wall motion abnormalities after surgical intervention. The hospital records of twenty-five consecutive patients in CS were reviewed retrospectively. Regional wall motion was assessed preoperatively by ventriculography and postoperatively by 2D echocardiography (Sonotron Kardio VUE 60) after 1 and 3 days and at the day of discharge from the surgical ward (7-10 days). The left ventricle was divided in three segments according to the blood supply: LAD artery (antero-lateral wall), circumflex artery (lateral wall), and right coronary artery (inferior and basal wall). Regional wall motion was analyzed with the use of a scoring system in which grading was from 0 to 4 according to the following criteria: 0 = hyperkinesia, 1 = normokinesia, 2 = hypokinesia, 3 = dyskinesia, 4 = akinesia. Postmortem examination was performed in 8/9 patients. Data are presented as mean +/- SD. Significant differences were defined as probabilities for each test of p less than 0.05. The hospital mortality was higher for patients with acute coronary occlusion as compared to those with acute valvular disease or VSD (54.5%, 27.3%, 0%, resp.). The cause of death was cardiac in 7/9 patients. However, postmortem examination revealed loss by infarction of only moderate quantities of myocardium which could not explain the severe postoperative heart failure in those patients. Previous myocardial infarctions and preoperative cardiac arrest were significant risk factors for hospital mortality. In all patients with acute coronary occlusion (11/11) at least one region of the left ventricle was either a- or dyskinetic in the region supplied by the acute occluded vessel. In addition five patients had akinetic regions due to previous infarctions. The remaining remote myocardium was hypocontractile due to significant stenosis in coronary arteries supplying remote areas. Of 10 dyskinetic segments before surgical intervention, 5 were akinetic postoperatively, and only 5 developed slight hypokinetic contractions. The overall hypokinetic regions were not different as compared to the preoperative data (36.4% vs 39.4%). The normokinetic segments increased from 9.1% to 33.% (p less than 0.05).

Coronary Disease↗

PubMed1990

[Retrobulbar irradiation of endocrine ophthalmopathy: a comparison between 10 and 16 Gy total dose].

Severe Graves' ophthalmopathy has been treated in 44 cases by orbital irradiation. 36 out of 37 patients showed a good response or a suspend of the progressive disease. In 17 out of 33 primary irradiations a dose of 10 Gy and in 16 cases a dose of 16 Gy was applied. Measured by ophthalmopathy-index significant better results have been achieved by a total dose of 16 Gy. Because of recurrence after primary irradiation of 10 Gy a re-irradiation became necessary in 35% of the cases. Primary irradiation of 16 Gy has required no further treatment during the same time of observation. A single series of 16 Gy irradiation has shown better results than two series of 10 Gy irradiation concerning the proptosis and alleviation of symptoms.

Adult↗

PubMed1989

[The effect of chemotherapy on survival time in advanced breast carcinoma].

Survival time of 119 consecutive patients with metastasizing carcinoma of the breast who had been treated with various chemotherapeutic schedules after radical operation was determined retrospectively. 57 women received chemotherapy and hormones, as well as radiotherapy, while 62 had radiotherapy plus hormone treatment. The mean prolongation of life in the former group over that of the latter was 12 months (P less than 0.01). Although chemotherapy delayed death, the dynamics of the cancer were not fundamentally affected. The chemotherapy-induced prolongation (2.5 months--five years) was independent of any extra risk, primary location of the metastases or age.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1989

[The value of magnetic resonance tomography during radiotherapy of childhood tumors in the posterior fossa and the pineal region].

MRT is a highly sensitive method for the diagnosis of childhood tumours in the posterior fossa. Since it demonstrates tumour extent better than does CT, MRT is the method of choice for radiotherapy planning. The result of treatment can be judged morphologically and by measuring relaxation times. Changes due to treatment can be recognised more easily than by CT. A disadvantage of MRT is lack of specificity, since various processes may lead to an equal increase in T1 and T2 times.

Brain Neoplasms↗

PubMed1988

[Intraoperative electron irradiation of malignant pancreatic tumors--initial experiences at Grosshadern].

15 patients with locally unresectable pancreatic carcinomas were treated by IORT and bypass surgery. 13 patients without distant metastases were additionally treated by external beam irradiation. Although only one patient had a local failure, the median survival was only eight months. Severe complications were seen in eight patients, gastrointestinal bleeding occurred in six patients and was the cause of death in three patients. The stop of weight loss and the impressive pain relief within ten days after IORT demonstrate the significance of this treatment modality with respect to palliative effects.

Adenocarcinoma↗

PubMed1988

Endoscopy of the gallbladder as control of gallstone therapy with methyl-tert-butyl ether.

We report on a 36-yr-old woman with six gallstones measuring 2.1 cm each. Within 21 h of methyl-tert-butyl ether (MTBE) treatment, the stones had dissolved to a small amount of residue. As could be seen from cholesterol concentrations of samples of aspirated gallbladder bile and MTBE fractions, the dissolution process was slow to begin with, and gained momentum during hours 6-11, after which it decelerated. We discontinued treatment after 20 h, since the stone residue showed no change. Cholecystoscopy performed with an Edwards angioscope via a catheter showed that there were no stone remnants, but that there were flat polyps on the gallbladder wall. One hour later, we stopped the therapy. Cholecystoscopy is a useful method of assessing the results of MTBE treatment.

Adult↗

PubMed1988

[Results of interstitial radiotherapy using I-125 seeds in the treatment of prostatic cancer].

30 patients with localized adenocarcinoma of the prostate were treated with pelvic lymphadenectomy and I-125 interstitial implantation from 1980 to 1985 (21/30 T3-tumors and 14/30 with poor differentiation). The mean follow-up is 59.5 months (range 18 to 88 months). The crude, progression-free and local progression-free survival rates (Kaplan-Meier) for all patients are 68%, 61% and 71% respectively. But, the progression-free survival is 39% in patients with G3-tumors after five years and only 25% in patients with T3 G3-tumors after four years. The local progression rate was 33% in patients with T3-tumors. We did not observe any late intestinal side-effects, but 11/30 (37%) patients suffered from later urinary flow problems caused mainly by local tumor progression. Therefore, we regard interstitial implantation with I-125-seeds as an alternative treatment to radical prostatectomy in patients with T1, 2 G1, 2-tumors but as insufficient in patients with T3 G3-tumors.

Adenocarcinoma↗

PubMed1988

[Progressive lymphangiokeratoma and angiosarcoma (Stewart-Treves syndrome) in congenital lymphedema].

Three unusual clinical and histopathological changes were found in a 59-year-old male patient with congenital lymphedema of the lower left leg. Firstly, a keratotic lymphangioma had developed in the course of only a few years and in the end involved the entire left leg up to the buttocks--far beyond the edematous area. Secondly, concealed beneath the lymphangiokeratoma, a solitary tumor almost the size of a table-tennis ball was found on the outer side of the lower left leg. Histopathologically, the tumor proved to be a malignant angiosarcoma, which had grown over a period of some months. It was characterized histopathologically by solid and angiomatous differentiation. Thirdly, the superficial and deep lymph vessels revealed remarkable atypia and papillary proliferations of endothelial cells. After amputation of the left leg at the thigh, with complete removal of the angiosarcoma, but leaving the pathologically altered vessels in the upper part of the left leg and the buttocks, no clinical signs of metastases of progression have been noted during the first year after operation.

Amputation, Surgical↗

PubMed1988

[A ventral mantle technic with dorsolateral mediastinal saturation in the radiotherapy of Hodgkin's disease].

Between 1975 and 1981 69 patients suffering from Hodgkin's disease stage I to III were treated by radiotherapy exclusively. In contrast to the standard modalities the mantle was treated only through a ventral portal with dorsolateral boost to the posterior mediastinum. The geometrical treatment arrangement and the modalities of dose application yielded favourable dose distributions and single doses within the target volume. The analysis of failures showed no in field-failure, six marginal recurrences, and 17 distant failures, which are not related to the technique of irradiation. The described technique of mantle irradiation seems to be equivalent to the standard technique with regard to tumor control and side effects.

Cobalt Radioisotopes↗

PubMed1987

Acute hemodynamic effects of the vasodilating and beta-blocking agent carvedilol in comparison to propranolol.

In a randomized double-blind study, oral doses of 50 mg carvedilol were compared to 40 mg propranolol in 16 male patients with coronary heart disease (12 without significant stenosis after percutaneous transluminal coronary angioplasty) at rest, during and after exercise, and before and 80 min after drug application. Systemic and pulmonary pressures, heart rate, cardiac index, and lower limb blood flow were measured, and systemic and pulmonary resistances calculated. Carvedilol does not lead, as the classical beta-blocker propranolol does, to an increase in systemic or pulmonary resistance, nor to a decrease in cardiac output, or to an increase of the pulmonary capillary wedge pressure during exercise. In contrast to propranolol, the postexercise lower limb blood flow has increased significantly. The differences in action between the two beta-blockers can be explained by the vasodilating properties of carvedilol. Due to these acute effects, carvedilol may be of advantage compared to propranolol in the treatment of peripheral occlusive artery disease, hypertension, and coronary vasospasm.

Adrenergic beta-Antagonists↗

PubMed1987

[Irradiation of chemodectomas].

The rarely occurring, slowly growing glomus tumours of the inner ear, bulbus jugularis or carotis bifurcation, according to the site of the tumour, can be the cause of loss of hearing, tinnitus, vertigo, pain and cranial nerve destruction. As a result of radiotherapy, after having applied 45 Gy, the size of the tumour decreases only very slowly. Although radiotherapy yields very good results, chemodectomas are usually operated on. However, radiation can be applied as first choice of treatment because of its simplicity and because it is well tolerated by the patient. If surgery is used as first choice the rate of recurrence is higher and one should therefore always consider the use of radiotherapy. Our own results with eight patients confirmed that glomus tumours respond well to radiation. This is generally also known from the literature on this subject.

Brain Neoplasms↗

PubMed1987

[Rotation angioplasty--a new procedure for reopening and dilating blood vessels. Experimental findings].

16 fresh postmortem specimens of human femoral and popliteal arteries with severe atherosclerosis were removed and angiography was performed. Eight vessels were completely occluded and eight showed stenoses of up to 60%. All occluded vessels were heavily calcified. The duration of occlusion, estimated according to the patient's history, ranged from 1 to 2 years. In one case, a duration of 18 months was documented by angiography. The lengths of the occlusions were between 5 and 12 cm. A rotating catheter was introduced through a 9F guiding catheter. All stenosed vessels were passed and seven out of eight occluded vessels, in which passage was not possible using conventional wires, were successfully reopened at low speed rotation of 200 rpm. Angiography, as well as histology, showed no perforation, and angioscopy revealed a smooth surface of the new channel. In three vessels this new channel was dilated with a balloon catheter and in one with an elastic element under rotation. It is concluded that with the new technique it is possible to reopen totally occluded human arteries which cannot be passed by conventional methods.

Angioplasty, Balloon↗