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Biomedical subjects

V Schlosser

Publications and source records attributed to V Schlosser.

At least 19 recordsLinked to original sources
PubMed1999

Photodynamic effects in vitro in fresh gynecologic tumors analyzed with a bioluminescence method.

Photodynamic therapy (PDT) is a promising alternative method for clinical cancer treatment. In the present study, cells from four breast carcinomas, seven ovarian carcinomas of various stages of differentiation, and ascites from a diffuse metastatic tumor were treated by PDT in vitro. Tetra(m-hydroxyphenyl)-chlorin (m-THPC) was used as the photosensitizer. Surviving cell rate was evaluated by the ATP-Cell-Viability-Assay (ATP-CVA), which measures light production as an interaction of intracellular ATP with the luciferin-luciferase complex. The most effective PDT of the tumor cells was achieved at an m-THPC concentration of 0.2 microgram/ml following incubation of the cells with photosensitizer for 24 hours. PDT toxicity resulted in a cell survival rate of 1% to 42% compared to untreated control cells (survival rate of control = 100%). The inhibitor concentration IC50 of m-THPC was determined both in the dark (dark toxicity) and in combination with laser irradiation. IC50 was defined as the concentration of photosensitizer which caused 50% of cell death. The IC50 values were heterogeneous in all tumor specimens examined. IC50 values for dark toxicity were on average 0.14 microgram m-THPC/ml for primary ovarian carcinoma, 2.16 micrograms m-THPC ml for refractory ovarian carcinoma and 0.3 microgram m-THPC/ml for breast carcinoma. After PDT, average IC50 value for refractory ovarian carcinoma was 0.04 microgram m-THPC/ml, for primary ovarian carcinoma 0.05 microgram m-THPC/ml and for breast carcinoma 0.03 microgram m-THPC/ml. These data might indicate that clinical PDT of gynecological carcinoma requires individual treatment conditions to achieve optimal results.

Breast Neoplasms↗
PubMed1996

[Endoluminal therapy of infrarenal abdominal aortic aneurysms: a new interventional technique].

PURPOSE: With a series of 31 transluminal stent-graft procedures, we assessed the feasibility and clinical effectiveness of a new stent-graft for the treatment of infrarenal abdominal aortic aneurysms (AAAs). METHODS: We treated the patients (male; mean age 71 years) with straight or bifurcated nitinol stents covered with woven dacron graft material for infrarenal eccentric saccular AAA (n = 4) or AAA involving the bifurcation and the common iliac arteries (n = 27). The 18-F delivery system was advanced via a surgical arteriotomy and the stent-graft was placed under fluoroscopic control. Follow-up period ranged from 8 days to 9 months. RESULTS: The implantation of the stent-grafts was technically successful in 30/31 cases. Procedure-related complications were acute hepatic failure due to gastric bleeding in a patient with liver cirrhosis, graft occlusion due to emboli originating from the left atrium (n = 1), macro-embolisation (n = 3), local haematoma (n = 1) and av-fistula (n = 1) requiring surgery. A post-implantation syndrome with leukocytosis and elevated C-reactive protein was observed in all patients. CONCLUSIONS: Endoluminal repair of infrarenal AAA with use of dacron covered nitinol stent-grafts is feasible, safe and clinically effective. However, careful long-term evaluation is necessary.

Aged↗
PubMed1996

Abdominal aortic aneurysms: preliminary technical and clinical results with transfemoral placement of endovascular self-expanding stent-grafts.

PURPOSE: To evaluate treatment of infrarenal abdominal aortic aneurysm (AAA) with a new endoluminal stent-graft. MATERIALS AND METHODS: In 26 male patients, straight or bifurcated nitinol stents covered with woven Dacron graft material were implanted to treat eccentric saccular AAA (n = 3) or AAA involving the bifurcation and common iliac arteries (n = 23), with follow-up from 8 days to 8 1/2 months. RESULTS: Implantation was technically successful in all but one of the 26 (96%) patients (leak of the stent-graft for more than 3 months necessitated implantation of an additional covered stent). In seven of the 26 patients, minor residual perfusion persisted immediately after implantation, but complete thrombosis occurred within 7 days. Five procedure-related complications occurred: distal embolization (n = 2); local hematoma, which necessitated surgery (n = 1); acute hepatic failure due to gastric bleeding, in a patient with liver cirrhosis (n = 1); and stent-graft occlusion due to emboli originating from the left atrium (n = 1). CONCLUSION: Exclusion of AAA from circulation was feasible, safe, and clinically effective with the new stent-graft.

Aged↗
PubMed1996

[Initial clinical experiences with endovascular stent-grafts for treatment of infrarenal abdominal aortic aneurysm].

With a series of 34 transluminal stent-graft procedures, we assessed the feasibility and clinical effectiveness of a new stent-graft for the treatment of infrarenal abdominal aortic aneurysms (AAAs). We treated 34 male patients (mean age 71 years) with straight of bifurcated nitinol stents covered with woven Dacron graft material for infrarenal excentric saccular AAA (n = 3) or AAA involving the bifurcation and the common iliac arteries (n = 31). The 18-F delivery system was advanced via a surgical arteriotomy and the stent-graft was placed under fluoroscopic control. Follow-up period ranged from 8 days to 13 months. The implantation of the stent-grafts was technically successful with exclusion of AAA in 31/34 cases (91%). In 2 patients, there was a persisting leak at the distal end of the endoprosthesis after treatment; in another, marked coiling of the external iliac artery impeded the delivery system to be advanced and consecutive rupture resulted in conversion to surgical repair. Other procedure-related complications were acute hepatic failure due to gastric bleeding in a patient with liver cirrhosis, graft occlusion due to emboli originating from the left atrium (n = 1), local hematoma (n = 1), and AV-fistula (n = 1) requiring surgery. A post-implantation syndrome with leucocytosis and elevated C-reactive protein was observed in all patients. Endoluminal repair of infrarenal AAA with use of Dacron covered nitinol stent-grafts is feasible, safe and clinically effective. However, careful long-term evaluation is necessary before it will become clinical practice.

Aged↗
PubMed1996

[Surgical therapy of chronic traumatic aortic aneurysm].

Rupture of the aorta that usually occurs with major blunt trauma of the chest is associated with a high mortality, and only 2% of the patients survive long enough to develop a false aneurysm. Although symptom-free latent period is not rare, there is evidence of progression. Since 1970 we operated on 28 patients (24 male and 4 female, mean age 41.2 years) for chronic traumatic aneurysm of the descending aorta. A previous blunt trauma of the chest had certainly occurred in 23 cases (3 months to 20 years before) and was likely in 4 patients; in one young woman the aneurysm developed after percutaneous angioplasty of a coarctation. In 26 patients surgical repair consisted in a Dacron tube interposition, and in 2 cases patch repair was adequate. In 11 cases the "clamp and repair" technique was applied, while in 17 patients extracorporeal circulation was established to perform the reconstruction, two of these cases were operated with hypothermic circulatory arrest. Although there was no correlation between the occurrence of complications and the applied procedure, we lately turned to establish cardiopulmonary bypass in all cases with regard to a better control of the hemodynamics during clamping, the possibility of direct retransfusion of blood, and the option to extend the procedure, if necessary. In view of the facts, that traumatic thoracic aneurysms develop late complications in about 75% of the cases, and the morbidity in elective surgery is of a low figure, we conclude, that surgery of such lesions is mandatory, once the diagnosis has been established, and that an expectant attitude in the treatment is justified only in exceptional cases.

Adult↗
PubMed1993

Diltiazem provides anti-ischemic and anti-arrhythmic protection in patients undergoing coronary bypass grafting.

In 91 patients undergoing elective coronary bypass grafting, the anti-ischemic and anti-arrhythmic efficacy of a 24-hour infusion of either the calcium antagonist diltiazem (0.1 mg/kg per h, n = 44) or nitroglycerin (1 micrograms/kg per min, n = 47) were compared. Myocardial ischemia was diagnosed by Holter monitoring and the repeated assessment of 12-lead ECG and serum enzyme levels and defined as a transient ischemic event, transient coronary spasm or myocardial infarction. The two groups did not differ with respect to preoperative and operative data. Postoperatively, the average heart rate and pulse pressure rate were significantly lower in the diltiazem group. The incidence of postoperative atrial fibrillation (4.5 vs 19.1%, P < 0.01), transient coronary spasm (2.3 vs 11.4%, P < 0.05) and myocardial infarction (4.5 vs 8.5%, not significant) and the frequency of ventricular premature couplets/h (12.1 +/- 4.5 vs 18.1 +/- 5.1, P < 0.05) and ventricular runs/h (2.5 +/- 0.8 vs 6.5 +/- 2.8, P < 0.05) were lower in the diltiazem as compared to the nitroglycerin group. In addition, diltiazem-treated patients had significantly lower postoperative peak values of creatine kinase-MB (19.3 +/- 11.6 vs 29.3 +/- 20.6, P < 0.05). In conclusion, perioperative infusion of diltiazem is effective in reducing the incidence and extent of arrhythmias and myocardial ischemia in patients undergoing elective coronary bypass grafting as compared to patients receiving nitroglycerin.

Arrhythmias, Cardiac↗
PubMed1993

Growth of "new" coronary vascular structures by angiogenetic growth factors.

The efficacy of the human angiogenetic heparin-binding growth factor I (HBGF-I) to initiate site-directed growth of new blood vessels from the aorta into the myocardium was studied. First, manipulated Escherichia coli bacteria, which had received the human mRNA-transcript for HBGF I into their genetic material, were cultivated. The growth factor derived was purified using heparin-Sepharose affinity chromatography. The separation and characterization of biologically active alpha- and beta-chains was carried out using high pressure liquid chromatography (HPLC) of dialyzed and lyophilized samples from the heparin-Sepharose column. One microgram HBGF I (alpha-ECGF) was bound to polytetrafluoroethylene (PTFE) sponges, precoated with collagen type I, and implanted between the aorta and the myocardium of the left ventricle in experimental rats. Twelve growth factor implants in the experimental group were compared to six controls receiving uncoated PTFE sponges for 9 weeks. Digitized computed angiography showed new blood vessels between the aorta and the myocardium in 11 of the 12 experimental animals, and retrograde coronary perfusion by these "new" vascular structures could be seen. Histology showed no specific structures in the control group (without HBGF I). In the experimental group (with HBGF I) individual vessels with highly differentiated endothelial and smooth muscle cell layers were evident. Our experiments proved the feasibility of induced, site-directed angiogenesis. It is possible to initiate in vivo growth of new "coronary" vascular structures between the aorta and the myocardium.

Animals↗
PubMed1992

[Accusation of malpractice in cardiovascular surgery].

The reproach of malpractice in cardio vascular surgery seems to be up to now quite seldom in comparison with other While in cardiac surgery the acknowledgement was found extremely seldom in vascular surgery acknowledgement of malpractice reproach must be expected in about 50%. In cardiac surgery mainly new neurological deficits are content of malpractice reproach; in vascular surgery artery injuries and surgical procedures to correct varicose veins are most often involved. In order to prevent or to minimise those malpractice reproaches an optimal communication between the surgeon and the patient, an extensive informed consent and a very strict medical indication for surgery are imperative.

Cardiovascular Diseases↗
PubMed1992

Isolation of the membranes from secretory organelles (trichocysts) of Paramecium tetraurelia.

We present for the first time a method for isolation of the membranes of extrusive organelles (trichocysts) from sterile culture of different strains of Paramecium tetraurelia. First, trichocysts are isolated according to a new method (Glas-Albrecht, R. and Plattner, H. (1990) Eur. J. Cell Biol. 53, 164-172) with high purity and yield. Then the organelles are subjected to osmotic swelling. Since trichocysts then easily 'decondense' and entangle membranes, these cannot be isolated directly by centrifugation, but only by passage through a filter and subsequent centrifugation. Purity of membrane fractions is analysed by electron microscopy and SDS-PAGE, combined with silver staining or, after biotinylation, by avidin-peroxidase labelling. Molecular masses resolved in our gels are in a range from less than or equal to 15 to greater than or equal to 105 kDa. Main bands obtained with nd9-28 degrees C trichocyst membranes (most bands also being common to wild type trichocysts) are of about 16.5, 19-21, 27-29, 33-34, 44-45 (strong), 47-48 (strong), 57, 61, 65 (strong), 68-71, 75, 81, 94-95 (strong), 104 and greater than or equal to 110 kDa, from a total of approx. 23 bands resolved. There is no remarkable occurrence of dominant protein bands from trichocyst contents ('trichynins'), though these might represent up to 10(3)-times more of the total trichocyst proteins. The ratio of phospholipid/protein is approx. 0.2 mg/mg. The methodology developed might also be valuable for the isolation of extrusome membranes from some other protozoan species.

Animals↗
PubMed1992

The influence of obesity on perioperative morbidity: retrospective study of 502 aortocoronary bypass operations.

The incidence of perioperative complications after coronary artery surgery was investigated by a retrospective study of all 502 patients undergoing coronary artery bypass graft (CABG) surgery in our Department between January 1st and December 31st of last year (1990). Furthermore, the influence of obesity on the early results of surgery was assessed and the effect of preoperative weight reduction on perioperative complication rates examined. Obese patients had a greater incidence of left-stem coronary artery stenosis (p less than 0.001), hyperlipidaemia (p less than 0.05), hypertension (p less than 0.05), diabetes mellitus (p less than 0.02), and were in general younger at the time of operation (57.9 +/- 8.4 vs. 60.8 +/- 8.5 years). There were no differences in the surgery performed and in operative mortality, but there were some in perioperative morbidity. Obese patients had higher rates of infection (p less than 0.02), sternal dehiscence (p less than 0.02), arrhythmias (p less than 0.02) and myocardial infarction (p less than 0.02). No significant differences were identified in obese patients with or without preoperative weight reduction, although there was a trend of better postoperative recovery and results in patients having undergone preoperative weight reduction. Analysis of our results demonstrated obesity to be an independent risk factor for perioperative complications, hospital morbidity, and length of hospitalization.

Aged↗
PubMed1992

Added hospital stay due to wound infections following cardiac surgery.

To determine the prolongation of hospital stay due to postoperative wound infections following cardiac surgery, a prospective cohort study was performed by matching multiple control patients without infection to each infected patient (= case). Out of 22 cases, no patient died. No case had to be excluded from the matching process because of a lack of suitable control patients. The maximum number of controls per case was 10. The mean added stay was 12.2 days constituting a considerable prolongation of stay due to wound infection in cardiac surgery.

Adult↗
PubMed1992

[Non-cardiac complications after open heart surgery].

The most important complications after open heart surgery are neurological, gastrointestinal (GI), and renal complications. New neurological deficits may occur in 1%, and neuropsychiatric alterations may be observed in 40%. In 6% peripheral neurological damage occurs. Endoscopy in all patients whose clinical history suggests signs of gastric ulcer disease, and perioperative H2-blocking therapy are effective in reducing severe GI bleeding to 1%. Small-bowel ischemia is a rare but high risk complication. Hepatitis due to homologous blood transfusion is as low as 2%-3%. Postoperative renal insufficiency occurs in 1% needing hemodialysis. Good hemodynamic condition during and after surgery reduces the frequency of extracardiac complications as well as the reduction of use of homologous blood transfusions for open heart surgery.

Heart Diseases↗
PubMed1991

[Prolongation of hospital stay by nosocomial pneumonia and wound infection].

From June 1988 to September 1989, a prospective survey comprising a total of 1183 patients in a university hospital was carried out to ascertain the additional length of stay in intensive care units because of nosocomial pneumonia associated with artificial ventilation (418 patients, 296 men, 122 women, mean age 48.8 +/- 21 years, ventilated for more than 24 h) or by postoperative wound infections (765 patients, 501 men, 264 women, mean age 60 +/- 11 years, after operations on the large bowel, heart or biliary tract). Each patient with a nosocomial infection was matched against a variable number of control patients (for cases of pneumonia a maximum of 6, for wound infections a maximum of 10) without nosocomial infection. Pneumonia developed in 100 (23.9%) of artificially ventilated patients, and 46 of these patients together with 101 controls were entered into the matching procedure. 24 patients with pneumonia had to be excluded from analysis because no controls could be found for them, and also 30 patients who died while in the intensive care unit. 49 (6.4%) of the surgical patients contracted postoperative wound infections. 43 of them, together with 210 controls, were entered into the matching procedure. Among patients with pneumonia the average additional duration of stay was 11.5 days, and among patients with post-operative wound infections it was 13.9 days. The results confirm that nosocomial infections contribute substantially to prolongation of hospital stay and hence to the costs.

Adult↗
PubMed1991

Reduction of the risk of surgery for abdominal aortic aneurysms by extended coronary diagnostics and therapy.

The morbidity and mortality in the surgery of abdominal aortic aneurysms are essentially determined by the coronary risk profile of the patient. Preoperative coronary artery diagnostics with the potential consequence of a coronary revascularization as procedure before the aneurysmectomy seems to be mandatory to decrease the risk of treatment. Out of 223 patients treated at our institution for abdominal aortic aneurysm, 68 (30.5%) had to undergo extended cardiological diagnostic procedures, and 37 (16.6%) needed a coronary angiography; in 23 patients (10.3%) myocardial revascularization was performed prior to the aneurysmectomy. Since routinely performing this thorough investigation of the coronary risks, the mortality of surgery for aortic aneurysm has been clearly reduced.

Angioplasty, Balloon, Coronary↗
PubMed1991

[Histologic examinations of internal mammary artery, saphenous vein and aorta specimens collected during heart surgery].

133 patients with coronary heart disease were treated surgically. 60 patients had Internal Mammary Artery (IMA) grafting performed together with saphenous vein grafts (IMA group), another 70 patients had saphenous vein grafts only (SVG group). Material for histological examination was intraoperatively taken from saphenous vein and ascending aorta and in IMA group also from the distal part of internal mammary artery. The intensity of atherosclerosis was estimated with 5-grade scale from 0 to 4 (0-no atherosclerosis, 1-minimal, 2-insignificant, 3-moderate, 4-pronounced). To visualize and to assess the blood flow through the internal mammary artery Digital Subtraction Angiography (DSA) was performed between day 6 and day 8 postoperatively in the IMA group. Results obtained were correlated with the intensity of atherosclerosis estimated histologically and the numeric data were statistically analysed. In the IMA grafts mean atherosclerosis intensity was 0.94 which is the evidence of minimal atherosclerotic changes. In saphenous vein the corresponding value was in the IMA group 2.14 and in the SVG group 2.17, in aortic scraps 2.64 in the IMA group and 2.73 in the SVG group. Patients in the SVG group were average 8.4 years older than in the IMA group. The difference is statistically significant. Despite the age difference, the intensity of atherosclerosis was not statistically different in aortic and saphenous vein scraps. Among 63 patients in the IMA group in 31 patients (49.2%) no atherosclerosis was found during histological examination and in 32 patients (50.8%) changes ranged from minimal to moderate. There were no IMA grafts with the pronounced atherosclerosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Acute and chronic aortic rupture. Management without and with a protective bypass procedure].

The use of partial cardiopulmonary bypass in the surgery of thoracic aortic ruptures is still a matter of controversey. Since 1970, 38 patients with thoracic aortic rupture have been treated at our institution, 13 in a acute or subacute stage and 25 with traumatic aneurysm. Partial cardiopulmonary bypass was installed in 13 cases, and in 23 patients the "clamp and repair" technique was performed. Although there was no coherence between the occurrence of complications and the applied procedure, we prefer the use of partial cardiopulmonary bypass in view of the advantages in safe distal perfusion, direct retransfusion of blood, controlled decompression of the left heart, and the possibility to extend surgery to the aortic arch.

Adult↗