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Biomedical subjects

F Langer

Publications and source records attributed to F Langer.

At least 37 records · Page 2Linked to original sources
PubMed2000

Effects of skeletonized versus pedicled internal thoracic artery grafts on free flow capacity during bypass.

The free flow of skeletonized ITA grafts was compared with that of pedicled ITA grafts. One hundred patients with coronary artery diseases underwent elective CABG. In the group I (n = 50), the left ITA was dissected using the skeletonization technique. In the group II (n = 50), the ITA was harvested as a pedicled graft. Free flow of the ITA was recorded before and 15 min after intraluminal application of diluted papaverine. Mean arterial pressure was maintained at 9.31 kPa (70 mmHg). The results showed that before the application of papaverine, free flow of skeletonized and pedicled ITA grafts was identical between the two groups. After treatment with papaverine, the maximum free flow was significantly higher in the skeletonized ITA's in the group I (199.3 +/- 69.6 ml/min) than in the group II (145.7 +/- 70.3 ml/min, P < 0.05). There was on significant difference between the free flow after dilatation of the left and right ITA in the group I (left 199.3 +/- 69.6 ml/min, right 198.9 +/- 61.8 ml/min, respectively). It was concluded that preparation of the ITA with the skeletonization technique resulted in significantly higher free flow capacity than in pedicled grafts and would improve the results of arterial revascularization. The complication rate seems to be lower than with the conventional method.

Aged↗
PubMed2000

Increased apoptosis of hepatocytes in vascular occlusion after orthotopic liver transplantation.

Early vascular occlusion is liable to cause graft failure, and differential diagnosis between this condition and primary nonfunction (PNF) caused by preservation injury may be difficult. Apoptosis has been detected in immunomediated cytotoxicity and is known to be triggered by mild ischemia. In a retrospective analysis we investigated the role of apoptosis in vascular occlusion, PNF, and acute allograft rejection to improve the differential diagnosis of early graft failure. The liver graft histology of 75 patients (46 male, 29 female) a median 47 (1-64) years of age was screened semiquantitatively for the rate of apoptosis on the hematoxylin-eosin stain (HE) and by the in situ end nick labeling technique (TUNEL). This cohort included all patients who developed PNF (n = 9) or vascular occlusion (n = 11) after orthotopic liver transplantation (OLT) in the years 1992 to 1996. Within this period of time we performed 205 OLTs on 189 patients. We further included 22 patients with early acute rejection and 11 controls. The highest rates of apoptotic hepatocytes were seen in vascular occlusion (P < 0.001). Grafts with PNF were explanted 1-3 days after OLT and showed hepatocytes that were 100% necrotic. Cases of acute early rejection showed a significantly higher apoptotic cell count than did normal controls (P < 0.003), increasing in direct proportion to the severity of rejection. Screening biopsies for the rate of apoptosis can improve the efficacy and accuracy of differential diagnosis of early graft failure.

Adolescent↗
PubMed2000

General compliance after liver transplantation for alcoholic cirrhosis.

In recent years, alcoholic cirrhosis has been accepted as an indication for OLT, compliance of patients suffering from alcoholic cirrhosis is still under discussion, however. 118 patients who had undergone OLT for alcoholic cirrhosis were considered for analysis. The mean follow-up time of the study population was 53.7 +/- 38.9 months. Compliance was defined by 3 parameters: 1. Sobriety. Fifteen (13%) out of 118 recipients suffered an alcohol relapse during the observation period. There was no difference between the groups with or without alcohol relapse concerning compliance with medication, incidence of rejection, or adherence to check-ups. 2. Drug-compliance. Nineteen recipients (16 %) were not within the target range with the immunosuppressive medication. Comparison of the compliant- and non-compliant groups produced a significant difference for late acute rejection, the other parameters being similar in the subgroups. 3. Adherence to appointments. Nearly all patients in the study population ( > 95 %) were compliant with both transplant and psychological appointments in the outpatient clinic. In conclusion, analysis of our data indicates that patients with OLT for alcoholic cirrhosis are compliant, although alcohol relapse occurs in 13 % of recipients.

Follow-Up Studies↗
PubMed2000

Radical surgical therapy of abdominal cystic hydatid disease: factors of recurrence.

A series of 74 consecutive patients (48 women, 26 men) were operated for abdominal hydatid disease between June 1949 and December 1995. The patients ranged in age from 15 to 81 years (median 49 years). In 69 cases only the liver was affected; two patients had concomitant extrahepatic disease (one spleen, one spleen and lung), and 3 had cysts in the spleen only. Cysts were multiple in 11 patients and calcified in 24. Conservative surgical procedures were used for 22 cysts in 20 patients [open partial (n = 3), open total (n = 6), closed total cystectomy (n = 9), marsupialization (n = 2), drainage (n = 2)] and radical surgical procedures for 72 cysts in 54 patients [pericystectomy (n = 41), wedge liver resection or hemihepatectomy (n = 25), splenectomy (n = 5), radical resection of a lung cyst (n = 1)]. Altogether 37 patients (50%) were given perioperative antihelmintic chemotherapy with mebendazole (18 patients) or albendazole (19 patients). Operative mortality rates were 5.0% after conservative surgery and 1.8% after radical surgery. Morbidity rates were 25.0% following conservative surgery and 24.1% following radical surgery. Antihelmintic therapy was well tolerated by all but five patients. All side effects were entirely reversible. Among the 74 patients, 60 (81.0%) were available for long-term follow-up (median 7.2 years; range 2.0-47.0 years). Recurrence of disease was seen in 9 of 60 patients at an interval of 3 months to 20 years from the first operation. The rate of recurrence was significantly lower after radical surgical procedures (p = 0.03) and after closed removal of the cyst (p = 0.04).

Adolescent↗
PubMed2000

[Combined glaucoma and cataract operation with foldable posterior chamber lens implantation. Long-term outcome and complications].

BACKGROUND: Glaucoma patients who need filtering surgery very often have cataracts as well. Combined glaucoma/cataract surgery entails a higher rate of complications and may endanger the results of glaucoma surgery. PATIENTS AND METHODS: This retrospective study investigated 223 eyes in 169 patients with uncontrolled glaucoma and cataracts. Each eye received filtering surgery and simultaneous phacoemulsification with implantation of a foldable posterior chamber lens. Mean follow-up was 32.5 months (6-57). RESULTS: Mean intraocular pressure was lowered from 24.6 +/- 6.2 to 16.4 +/- 3.4 mmHg (P > 0.0001). Visual acuity improved from 0.25 (0.01-0.5) to 0.5 (0.01-1.0). Preoperatively the mean number of medications was 2.4 (1-6) and postoperatively 1.3 (1 or 2). The most common perioperative complications were choroidal detachment (20.2%) and fibrin reaction in 10.1%; those occurring later than 4 weeks postoperatively were posterior capsule opacification requiring YAG laser capsulotomy (11.5%) and scarring of filtering bleb (7.7%). CONCLUSION: Complications encountered in the combined procedure were due mainly due to cataract surgery of glaucomatous eyes with narrow pupils and posterior synechiae. A shallow anterior chamber occurred in only one case. Despite complications the success rate in lowering intraocular pressure was comparable to that observed in filtering surgery alone.

Aged↗
PubMed2000

[Reconstruction of the bicuspid aortic valve].

Reconstruction of a regurgitant bicuspid aortic valve is a new alternative to aortic valve replacement. With concomitant aortic root dilatation adequate reconstruction is feasible by valve-sparing aortic replacement. Between 10/95 and 02/00, 30 patients underwent reconstruction of a regurgitant bicuspid aortic valve. Additional aortic replacement was performed in 23 cases. Valve reconstruction was performed by plication of the prolapsing leaflet. No patient died peri- or postoperatively. Freedom from aortic valve regurgitation > or = II as well as freedom from reoperation were 100% after 48 months. Reconstruction of a regurgitant bicuspid aortic valve is feasible with encouraging mid-term results. With concomitant dilatation of the ascending aorta, a combination of aortic replacement and valve reconstruction can achieve stable results even in bicuspid valve anatomy.

Adult↗
PubMed2000

[Progression of an intramural hematoma to dissection].

Intramural hematoma is a spontaneous, localized bleeding in the wall of the thoracic aorta without evidence of intimal tear. Clinically, intramural hematoma manifests itself as an acute thoracical pain in patients with hypertension and therefore shows parallels with the classical aortic dissection. In the literature there is controversial discussion whether intramural hematoma can be regarded as its own aortic pathology or a precursor in the development of classical aortic dissection. We present the case of a 66 year old male who showed an intramural hematoma of the descending aorta which rapidly progressed to classical dissection within 3 months. This finding was secondarily accompanied by a dilatation of the descending aorta which leads to operative treatment with replacement of the proximal aorta descendens. This case supports the hypothesis that intramural hematoma is a potential early manifestation of aortic dissection and at the same time stresses the necessity for frequent follow-up investigations and, if necessary, early operative therapy.

Aged↗
PubMed2000

Remodeling of the aortic root and reconstruction of the bicuspid aortic valve.

BACKGROUND: Currently, isolated reconstruction of a regurgitant bicuspid aortic valve can be performed with adequate early results. Dilatation of the proximal aorta is known to be associated with this valve anomaly and may be partially responsible for the development of primary regurgitation or secondary failure of valve repair. We have used repair of the bicuspid valve with remodeling of the aortic root as an alternative to insertion of a composite graft. METHODS: Between October 1995 and May 1999, 16 patients (12 men, 4 women, aged 35 to 73 years) were seen with a regurgitant bicuspid aortic valve and dilatation of the proximal aorta of more than 50 mm. All patients underwent repair of the valve using either coapting sutures alone (n = 12) or in combination with triangular resection of a median raphe (n = 4). Using a Dacron graft, the aortic root was remodeled and the ascending aorta (n = 16) and proximal arch (n = 4) replaced. RESULTS: No patient died. The postoperative degree of aortic regurgitation was less than grade II in all patients. Valve function has remained stable in all patients between 2 and 43 months postoperatively. CONCLUSIONS: Reconstruction of the regurgitant bicuspid valve in the presence of proximal aortic dilatation is feasible with good results by combining the root remodeling technique with valve repair.

Adult↗
PubMed2000

Ascorbic acid for amelioration of reperfusion injury in a lung autotransplantation model in sheep.

BACKGROUND: Reperfusion injury is the leading cause of early graft dysfunction after lung transplantation. Activation of neutrophilic granulocytes with generation of free oxygen radicals appears to play a key role in this process. The efficacy of ascorbic acid as an antioxidant in the amelioration of reperfusion injury after lung transplantation has not been studied yet. METHODS: An in situ autotransplantation model in sheep is presented. The left lung was flushed (Euro-Collins solution) and reperfused; after 2 hours of cold storage, the right hilus was then clamped (group R [reference], n = 6). Group AA animals (n = 6) were treated with 1 g/kg ascorbic acid before reperfusion. Controls (group C, n = 6) underwent hilar preparation and instrumentation only. RESULTS: In group R, arterio-alveolar oxygen difference (AaDO2) and pulmonary vascular resistance (PVR) were significantly elevated after reperfusion. Five of 6 animals developed frank alveolar edema. All biochemical parameters showed significant PMN activation. In group AA, AaDO2, PVR, work of breathing, and the level of PMN activation were significantly lower. CONCLUSIONS: The experimental model reproduces all aspects of lung reperfusion injury reliably. Ascorbic acid was able to weaken reperfusion injury in this experimental setup.

Animals↗
PubMed2000

Valve-preserving operation in acute aortic dissection type A.

BACKGROUND: The standard treatment in patients with acute aortic dissection type A (AADA) and aortic regurgitation is either supracommissural aortic or composite replacement of ascending aorta and valve. Valve-preserving surgical procedures provide a promising alternative. We retrospectively analyzed midterm results after these different approaches. METHODS: From October 1995 to December 1999, 52 patients (35 men, 17 women) underwent repair of AADA. Patient ages ranged from 30 to 83 years. Composite replacement was chosen for degenerated aortic valves or prior valve replacement (group A; n = 8). With normal root diameter, supracommissural replacement of the ascending aorta was performed (group B; n = 22). For preexisting root dilatation the aortic root was either remodeled (root diameter 30 to 50 mm, group C; n = 17) or the valve reimplanted within a vascular graft (root diameter more than 50 mm, group D; n = 5). RESULTS: All patients underwent either proximal (n = 46) or total (n = 6) arch replacement under circulatory arrest. Eight patients (15.4%) died (group A: n = 3; group B: n = 3; group C: n = 2). Freedom from aortic regurgitation of grade 2 or more at 2 years was 100% in groups A and D, 90.9% in group C, and 75% following supracommissural replacement. At 2 years freedom from proximal reoperation was 100% in groups A, C, and D and 84.5% in group B. CONCLUSIONS: In AADA valve-preserving root replacement leads to improved stability of aortic valve function without an increased operative risk. Midterm results are promising and may show further superiority over supracommissural aortic replacement in the future.

Acute Disease↗
PubMed2000

Comparison of aortic valve gradient during exercise after aortic valve reconstruction.

PURPOSE: Aortic valve preservation is a promising alternative to conventional composite replacement of aortic valve and ascending aorta. This approach may have a physiologic benefit compared with valve replacement similar to that seen in mitral valve reconstruction. We investigated aortic valve gradients at rest and during exercise in patients who had undergone valve-preserving aortic replacement and compared them with composite replacement of valve and aorta. METHODS: Four groups were studied: nine patients underwent composite valve replacement (group A: valve diameter, 23 to 27 mm), eight patients underwent remodeling of the aortic root (group B), and another nine patients had reimplantation of the aortic valve (group C). Healthy volunteers were studied as a control group (group D). Using continuous-wave Doppler echocardiography, all patients were examined on a bicycle ergometer for aortic valve gradients (0 to 75 W). RESULTS: There were no differences among the groups with respect to age, body surface, left ventricular end-diastolic diameter, fractional shortening, or left ventricular mass. Maximum resting gradients were significantly elevated in group A compared with groups B, C, and D (group A: 21.3 +/- 7.1 mm Hg; group B: 9.0 +/- 4.5 mm Hg; group C: 8.6 +/- 3.7 mm Hg; group D: 4.9 +/- 1.6 mm Hg; p < 0.05). At 75 W, group A exhibited significantly higher gradients than all other groups (group A: 31.3 +/- 7.5 mm Hg; group B: 13.9 +/- 6.6 mm Hg; group C: 12.8 +/- 3.5 mm Hg; group D: 9. 2 +/- 1.9 mm Hg; p < 0.05). There was no significant difference among the other groups. Both valve-preserving groups had only insignificantly higher gradients than the control group. CONCLUSION: Our data strongly support the suggestion that preserving the aortic valve restores nearly normal hemodynamic function of the aortic valve. Long-term observations will have to prove the clinical relevance of restoring physiologic aortic valve hemodynamics.

Adult↗
PubMed1999

Preservation solutions for transplantation.

Eurocollins has almost been abandoned because of the glucose disadvantage. UW is certainly the most used preservation solution for livers, kidneys, and pancreases with excellent clinical and experimental preservation data. UW can certainly be considered the current golden standard solution. However, the disadvantage of high viscosity, high price, uneasy handling of many 1-L bags, and the fact that the radical scavenger glutathion cannot be detected in the bags by chemical analysis (presumably due to diffusion) encourage competitors to produce new compounds with better cost to effect ratios. HTK has a firm place in cardiac preservation; by demonstration of equal safety and efficacy in preserving livers and kidneys, at least in the middle and lower range of cold ischemia time, HTK will be sued more frequently, particularly with the consideration of lower price and more easy handling aspects. The suggested high volume perfusion is not really necessary, calculation based on a total volume of 10 L for a multiorgan donor show significant cost reductions. Celsior is current only used for cardiac preservation. Beyond all aspects of conservation and preservation potencies of all these fluids, it must not be forgotten that cold ischemia itself is a risk factor for organ function. Therefore, cold ischemia time should be kept as short as possible. People are willing to accept 24 hours or more cold ischemia time in kidney transplantation because organ failure can be treated by dialysis. In other organs, where immediate organ function is essential, like in clinical heart transplantation, cold ischemia is hardly ever extended beyond 6 hours. Why are hearts and kidneys so different? Very likely, there is no difference, and the outstanding results in living unrelated kidney transplants is mostly due to short cold ischemia time.

Adenosine↗
PubMed1999

Amelioration of lung reperfusion injury by L- and E- selectin blockade.

OBJECTIVE: Reperfusion injury is the main reason for early graft failure after lung transplantation. Inhibition of the adherence of polymorphonuclear leukocytes to activated endothelium by blocking L- and E-selectins (antibody EL-246) could potentially inhibit reperfusion injury. METHODS: Reperfusion injury was induced in a left lung autotransplant model in sheep. After hilar stripping the left lung was flushed with Euro-Collins solution and preserved for 2 h in situ at 15 degrees C. After reperfusion right main bronchus and pulmonary artery were occluded leaving the animal dependent on the reperfused lung (control, n = 6). Pulmonary function was assessed by alveolo-arterial oxygen difference (AaDO2) and pulmonary vascular resistance (PVR), the chemiluminescence of isolated neutrophils, as well as the release of beta-N-acetyl-glucosaminidase (beta-NAG) served as indicator of neutrophilic activation. Extravascular lung water was an indicator for pulmonary edema formation. EL-246 group animals (n = 6) were treated additionally with 1 mg/kg BW of EL-246 given prior and during reperfusion. RESULTS: After 3 h of reperfusion five control animals developed alveolar edema compared to one animal in the EL-246 group (P = 0.08). AaDO2 (mm Hg) was significantly higher in the control compared to the EL-246 group (510 +/- 148 vs. 214 +/- 86). PVR (dyn x s x cm(-5)) was significantly increased in the control compared to the EL-246 group (656 +/- 240 vs. 317 +/- 87). Neutrophilic activation was significantly lower in the EL-246 group. Extravascular lung water was significantly lower compared to control (6.88 +/- 1.0 vs. 13.4 +/- 2.8 g/g blood-free lung weight). CONCLUSIONS: Treatment with EL-246 results in improved pulmonary function and less in vivo PMN activation in this experimental model. Further studies are necessary to evaluate the possible role of selectin blockade in amelioration of reperfusion injury in human lung transplantation.

Acetylglucosaminidase↗
PubMed1999

Endothelial protease-activated receptor-2 induces tissue factor expression and von Willebrand factor release.

A second protease-activated receptor (PAR-2) that could be activated by trypsin or more physiologically by mast cell tryptase has been recently cloned. Both the structure and activation mechanism of PAR-2 was similar to the functional thrombin receptor (PAR-1). Although many effects of the coagulation protease thrombin on the vascular endothelium could be attributed to PAR-1 activation, very little is known about the physiological and pathophysiological role of PAR-2. We investigated whether stimulation of PAR-2 on endothelial cells induced two cellular responses that play a central role in primary and secondary haemostasis: the release of high molecular weight von Willebrand factor (hmw-VWF) from Weibel-Palade bodies and the de novo synthesis of tissue factor (TF) mRNA and protein. Human umbilical vein endothelial cells (HUVEC) were incubated with agonists for PAR-2 at 37 degrees C. Both trypsin and SLIGKV increased TF mRNA and activity and induced the release of hmw-VWF due to elevated levels of cytosolic Ca2+. Trypsin (10 nm) induced a 6-fold increase of TF mRNA and reduced time until fibrin clot formation to 37%, indicating trebling of the cell surface located TF activity. Stimulation of HUVEC with the PAR-2 agonist peptide SLIGKV induced a dose-dependent increase of TF mRNA up to 6 times and TF activity up to 3 times. Release of hmw-VWF was achieved both after incubation of HUVEC with trypsin and SLIGKV and was directly depending on intracellular Ca2+ mobilization. To make results comparable to the functional thrombin receptor, homologous experiments were carried out using the PAR-1 agonists thrombin and SFLLRN.

Cells, Cultured↗
PubMed1998

Combined heart and kidney transplantation using a single donor: a single center's experience with nine cases.

BACKGROUND: Simultaneous double-organ transplants comprising various organ combinations have become frequent. The purpose of this article is to report on a single center's experience of simultaneous heart and kidney transplantation (HNTX) with particular emphasis on selection criteria and patient outcome. METHODS: From September 1990 to January 1997, nine patients underwent HNTX, receiving both grafts from a single donor selected on ABO blood group compatibility and a negative lymphocytotoxic crossmatch, but without regard to HLA-antigen matching. RESULTS: One patient died of acute humoral rejection of the cardiac graft shortly after surgery. Eight patients are alive and well and have normal cardiac and renal function at a mean follow-up of 44+/-28 months. CONCLUSION: HNTX offers a compelling therapeutic solution in the treatment of advanced cardiac and renal failure in carefully selected patients. Because the heart and kidney rejection episodes were independent of each other, rejection surveillance should be carried out separately for each transplanted organ.

Adult↗
PubMed1998

[Treatment of the aortic valve and ascending aorta. The significance of reconstructive methods on the aortic root].

BACKGROUND AND OBJECTIVE: The standard surgical repair of disease of the aortic valve and the ascending aorta has been combined replacement, which includes the disadvantage of inserting a mechanical valve. We have investigated an individualized approach which preserves the native valve. PATIENTS AND METHODS: Between October 1995 and October 1997, a consecutive total of 101 patients (72 men, 29 women, aged 21-83 years) underwent operations for disease of the ascending aorta: aortic dissection type A in 34 patients, aneurysmal dilatation in 67. Dilatation of the aortic arch was associated with aortic regurgitation in 58 patients. There were 11 patients with aortic valve stenosis or previously implanted aortic valve prosthesis among a total of 46 whose aortic valve was replaced (group II). Supracommissural aortic replacement with a Dacron tube was performed in 16 patients (group I) with normal valve cusps and an aortic root diameter < 3.5 cm. In 28 patients with an aortic root diameter of 3.5-5.0 cm the aortic root was remodelled (group III). Resuspension of the native aortic valve was undertaken in 11 patients with aortic root dilatation of > 5.0 cm (group IV). RESULTS: Operative intervention was electively performed in 72 patients, without any death. Of 29 patients operated as an emergency for acute type A dissection four died (14%). In 55 of the 58 patients with aortic regurgitation in proved possible to preserve native aortic valve (95%). In the early postoperative phase and after an average follow-up time of 11.8 months, transthoracic echocardiography demonstrated good aortic valve function, except in one patient each of groups III and IV who developed aortic regurgitation grades I or II. CONCLUSION: The described individualized approach makes it possible to preserve the native aortic valve in most patients with aortic regurgitation, at a low risk. Follow-up observations so far indicate good results of the reconstruction.

Adult↗
PubMed1998

Reduced susceptibility of electroporated tumor cell lines to killing by cytotoxic lymphocytes.

Electroporation is a widely applied method for gene or protein transfer into cells, and it is also used for electrochemotherapy of cancer. During gene transfection studies, electroporation was found to decrease transiently susceptibility of some tumor cell lines to alloreactive cytotoxic T lymphocytes (CTL) or lymphokine-activated killer (LAK) cells. In each cell line electroporation induced c-fos mRNA. In K562 cells HSP70 mRNA induction also occurred. Expression of Grp78, Bcl-2, CD95/Fas, or major histocompatibility complex class I molecules was not affected by electroporation.

Animals↗