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Biomedical subjects

T Fischlein

Publications and source records attributed to T Fischlein.

At least 37 records · Page 2Linked to original sources
PubMed1997

Long-term results of total repair of tetralogy of Fallot in adulthood: 35 years follow-up in 104 patients corrected at the age of 18 or older.

Long-term survival after surgical repair of tetralogy of Fallot (TOF) is reported to be excellent if the patients are corrected in childhood. However, age at operation has been demonstrated as an important risk-factor. The aim of our study was to investigate whether adult patients also benefit from surgery. From December 1958 to May 1977, 739 patients underwent a correction of their TOF with pulmonary stenosis at our institution. Foreigners (n = 52) and those who moved to a foreign country (n = 13) were excluded from further analysis. Sixteen patients were lost during follow-up (98% complete). Of the remaining patient population (n = 658; mean age: 12.2 +/- 8.6 years; range 2-67 years), 104 patients were 18 years or older at the time of correction. Operative (n = 25) and one-year (n = 8) deaths were excluded for long-term calculations, resulting in a study group of 71 patients. Actuarial 10, 20, 30, and 35-year survival rates were 94%, 93%, 83%, and 72% respectively, and not different from normal life expectancy. The most common cause of death was congestive heart failure (n = 3), followed by myocardial infarction (n = 2) and sudden death (n = 2). Parameters influencing longterm survival could not be detected. At follow-up (mean 27.7 years), more than 80% (n = 48) of the 58 survivors reported themselves to be in NYHA functional class I or II and 95% (n = 55) were in a better condition than before the operation. Repair of tetralogy of Fallot in adulthood shows excellent results with normal life expectancy for the patients.

Adult↗
PubMed1997

[On-site laboratory monitoring on the intensive care unit. Blood gas, electrolyte, glucose, hemoglobin and lactate determination with the CIBA Corning 865 Analysis System].

INTRODUCTION: For decision-making in the ICU, rapid and accurate analysis of vital laboratory parameters is essential. The industry provides devices which analyse these parameters on a decentralised setting and which are designed for use by non-laboratory personnel. We investigated whether accuracy and handling of a new analyser (Ciba-Corning 865, Chiron Diagnostics, Medfield, USA) are good enough for basing clinical decisions on the measured parameters. MATERIALS AND METHODS: The Ciba-Corning 865 allows measurement of blood gases, electrolytes, haemoglobin, glucose and lactate by use of photometric, ion-selective, enzymatic and electrochemical sensors in less than 18 microliters of whole blood. In a cardiac surgical intensive-care unit the accuracy of the device was tested by comparison to 61 measurements of quality control reagents, 48 tonometered blood samples and 536 parallel measurements in the clinical laboratory. Besides a 10-minute instruction, the participating personnel had no formal training with the device. RESULTS: The differences between measurements in quality control reagents and tonometered blood and the expected value were lower than 5%. The comparison with clinical laboratory measurements showed correlation coefficients from 0.94 (sodium) to 0.99 (glucose, lactate). The biases in Bland-Altman analyses were below 5%, the limits of agreement were found to be in a clinically acceptable range for all parameters. During the test period no technical problems occurred with the analyser and good acceptance by the personnel was found. CONCLUSIONS: The measured parameters were accurate enough to be used for therapeutic decisions in acute care medicine. Although it should not be a complete alternative to the clinical laboratory, because of rapid analyses, small sample volumes and easy handling the use of the Ciba-Corning 865 is advantageous for patients and users.

Blood Chemical Analysis↗
PubMed1996

25 years follow-up of patients after replacement of the aortic valve with a Smeloff-Cutter prosthesis.

Thirty years ago the Smeloff-Cutter double-caged ball prosthesis was developed for aortic valve replacement. Between 1967 and 1977 a total of 46 patients admitted to the University Hospital Munich underwent an isolated aortic valve replacement with the Smeloff-Cutter prosthesis. Postoperatively all patients received anticoagulation treatment with phenprocoumon (Marcumar). A retrospective follow-up of 95.6% of patients, representing 842 patient years, was completed. The corresponding actuarial survival rates after 10, 20, and 25 years were 69.1%, 47.4%, and 31.4%. The actuarial freedom rates from either valve-related complications, reoperations, or death were 72.9%, 47.4%, and 20.3%. Thromboembolism occurred in 1.41% per patient year, bleeding in 1.90%. The rates of valvular dysfunction, reoperation, and endocarditis were 1.16%, 1.16%, and 0.2% per patient-year. Today, of the surviving patients 81% are in NYHA Class I or II, 19% in NYHA Class III. No surviving patient deteriorated over the reported time in his or her functional NYHA classification. After 25 years the Smeloff-Cutter valve has proved to be a reliable prosthesis for aortic valve replacement and-together with the Starr-Edwards prosthesis-it has set a standard in longterm durability by which all other valve designs will have to be measured.

Adolescent↗
PubMed1996

In vitro endothelialization of bioprosthetic heart valves.

BACKGROUND AND AIMS OF THE STUDY: The main disadvantage of xenograft bioprosthetic heart valves is limited durability due to tissue degeneration. METHODS: To study possible alternatives to conventional bioprosthetic heart valves, glutaraldehyde preserved porcine aortic valve leaflets were precoated with fibronectin-heparin and acidic fibroblast growth factor (aFGF) to enhance cell proliferation. Furthermore, different methods of storage and preservation (1.0% benzoic acid, 1.0% sorbic acid, 0.05% and 0.5% dialdehyde starch) were compared to conventional preservation procedures. Valve leaflets were lined with adult human saphenous vein endothelial cells (1.0 x 10(4) AHSVEC/cm2). The different methods of preservation were compared to leaflets precoated additionally with 1.0 microgram/cm2 aFGF protein, derived from gene manipulated bacteria. Endothelial growth kinetics were studied and verified by an increase of activation following 3H-thymidine incorporation, while the maintained metabolic cell activity was demonstrated by prostacyclin (PGI2) release measurements. In subsequent experiments in vivo degeneration and mineralization were determined by subcutaneous implantation in rats for up to 40 days. RESULTS: Our results favored alternatively treated valve leaflets; endothelial cells grew to persistent monolayers in six to 12 days in contrast to conventional processed leaflets where no endothelial cell growth was possible. Atomic absorption spectroscopic assessment of subdermal valve implants showed significantly lower contents of calcium, magnesium and phosphate in alternatively treated leaflets. Furthermore, precoating of alternatively preserved valve leaflets with aFGF protein and endothelial cells improved in vitro and in vivo results significantly. CONCLUSIONS: Our study shows that endothelial cell growth as well as significantly reduced in vivo degeneration and mineralization of valve leaflets may be feasible if bioprosthetic heart valves are processed according to alternative, non-toxic conservation procedures and are precoated with angiogenic growth factor protein.

Adult↗
PubMed1995

Immunologic reaction and viability of cryopreserved homografts.

Homograft cell viability after cryopreservation was investigated and cytoimmunologic monitoring was performed during the early postoperative course to research possible immunologic reactions after allograft aortic valve replacement. After cryopreservation, morphologic observations were made, a nonradioactive cell proliferation assay was used, and prostaglandin I2 secretion of the remaining endothelial cells was determined. Cytoimmunologic monitoring was performed daily within the first 3 weeks postoperatively. An increase of the activation index greater than 1 was rated as an immunologic reaction. Maintained metabolic activity of graft endothelial cells after cryopreservation was confirmed by prostaglandin I2 release (9.24 +/- 3.48 ng/cm2 basic release and 20.1 +/- 5.76 ng/cm2 when stimulated with 25 mumol/L Na arachidonic acid). Cell proliferation was indicated after graft incubation with the nonradioactive viability kit (0.27 +/- 0.9 at 450 nm). Cytoimmunologic examinations (n = 861) after homograft implantation showed a more intense activation in patients with ABO-incompatible grafts (activation index 2.1 +/- 1.6, n = 16) than in those with ABO-compatible grafts (activation index 1.3 +/- 0.8, n = 17). In these groups, the duration of activation by cytoimmunologic monitoring was 2.8 +/- 1.5 days and 1.3 +/- 0.6 days, respectively (p < 0.041). No activation was observed in 8 patients after xenograft valve replacement (p < 0.01). Our data indicate that cryopreservation of homograft valves represents a cell- and tissue-protective preservation method. Postoperatively, all homograft valves caused immunologic reactions, which were reversible without immunosuppression treatment.

ABO Blood-Group System↗
PubMed1994

Cytoimmunological monitoring after homograft valve replacement.

Examination results concerning immunological reactions in cryopreserved allograft valves during the early postoperative course are so far not available. Cytoimmunological monitoring (CIM) is a well established method to prove rejection reaction after allograft transplantation and was used in this study. Allograft valves were harvested from patients who underwent heart transplantation, and did not require sterilizing in antibiotic solutions. The valves were dissected, conserved and subsequently frozen to -40 degrees C and stored in a freezing system at -196 degrees C. During the first 3 weeks following allograft implantation, CIM was performed daily. An activation index (AI) was determined from the cytological evaluation of the mononuclear concentrate in the peripheral blood. An increase of the AI > 1 was defined as an immunological reaction. As control we performed 98 CIM examinations in eight patients who underwent bioprosthetic valve replacement in the aortic position. Echocardiography (TTE and TEE) was used postoperatively as function control. Out of 16 patients who underwent cryopreserved aortic valve implantation in the aortic position, 336 CIM-results were obtained. An immunological reaction could be detected in all patients, starting on the 5th day on average. Comparing ABO-compatible (group I, n = 9) with ABO-incompatible (group II, n = 7) allografts, the AI-maximum in group I was 1.4 with a mean duration of 1.5 days. Group II was characterized by more intensive immunoreactions (mean = 2.3) which proved to be even more prolonged (mean = 3.3 days, P < 0.05). Nevertheless it became apparent that all observed immunological events were completely reversible without the need for immunosuppressive drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

ABO Blood-Group System↗
PubMed1994

Integrity and viability of homograft valves.

Since it has been suggested that the leaflet tissue viability influences durability after homologous valve replacement, we compared different harvest and preservation techniques in order to examine the quality and smoothness of homograft conservation. We analyzed human aortic and pulmonary valve leaflets obtained from 'heart-beating donors' (HBD) during heart transplantation and from 'non-heart-beating donors' (NHBD) during coroner's autopsies. Valves were either cryopreserved in liquid nitrogen or stored at 4 degrees C in nutrient medium similar to the procedure reported in our protocols of the homograft bank system. All grafts from NHBD had been antibiotically sterilized for 3 days beforehand. Morphological observations were made using light and electron microscopy and, in order to characterize the endothelial cell viability, a non-radioactive cell proliferation assay was used. The PGI2 secretion of the remaining endothelium was defined as the 6-keto-prostaglandin F1 alpha metabolite by an enzyme immunoassay. Observations in the scanning electron microscope revealed that, after cryopreservation, homografts show an almost confluent endothelium when processed within 24 h after harvest from HBD, but lack endothelial cells when obtained from NHBD. Cryopreserved grafts from NHBD exhibited an altered tissue structure with edema and vacuolization within the spongiosa of the leaflets as well as irreversible cell damage when examined under the light and transmission electron microscope. That the metabolic activity of HBD homografts was maintained was confirmed by proven PGI2 secretion (6150 +/- 1200 pg/3 ml M199 after cryopreservation), whereas specimens from NHBD showed a reduced (1950 +/- 730 pg/3 ml M199) and, after cryopreservation, almost no release (P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

In vitro endothelialization of a mesosystemic shunt: a clinical case report.

The existence of a confluently covering endothelium that is free of any thrombotic appositions can be proved 30 days after clinical implantation of an in vitro endothelialized expanded polytetrafluoroethylene graft. The recipient of the mesosystemic H-graft was a 69-year-old man who had a thrombosed portal vein following pancreatitis. Autologous endothelial cells were obtained from the external jugular vein under local anesthesia, applying the in situ cannulation technique. After low-density plating, first-passage mass cultures of 1.22 x 10(6) endothelial cells were obtained 14 days after vein excision. After precoating was accomplished with fibrinolytically inhibited fibrin glue, a 10 mm expanded polytetrafluoroethylene graft was confluently lined with the autologous endothelial cells at a seeding density of 1.2 x 10(5) cells/cm2. After a maturation period of an additional 9 days and the microbiologic exclusion of a possible infection, an 11 cm graft segment was implanted between the superior mesenteric vein and the inferior vena cava. In spite of a patent shunt the patient had a repeat bleeding episode, needed parenteral nutrition, and died of sepsis on day 30. Immediately after the graft had been taken out, specimens were processed by scanning electron microscopy and light microscopy for the immunohistochemical proof of the endothelial nature of the surface-covering cell layer. The entire graft surface displayed a confluent cell lining that was free of any thrombotic appositions. A strongly positive stain result for both factor VIII-related antigen and the fixation-resistant CD34 molecule identified these cells as endothelial. No alpha-actin-positive cells could be detected. The underlying protein matrix was well preserved and unaltered in thickness and appearance, compared with preimplantation samples. None of the specimens showed any evidence of infection. This human demonstration of an intact endothelium on a patent venous prosthesis further establishes in vitro lining as a method that actually creates a persistent and functioning endothelium on a synthetic graft surface.

Aged↗
PubMed1994

Endothelialization of cardiac valve bioprostheses.

The main disadvantage of implanted xenograft valves used in cardiac surgery is their poor clinical long-term result, due to early tissue degeneration. In order to improve the performance of such glutaraldehyde fixed bioprostheses, a biological coating with viable endothelial cells was suggested. Therefore, glutaraldehyde preserved bovine pericard patches, as well as commercially available xenograft valves, were lined using human venous endothelial cells or microvascular cells from the subcutaneous fat tissue. Before cells were transplanted into their new environment, grafts were treated with an amino acid solution in order to neutralize the cytotoxic effect of free aldehydes, and precoated with fibronectin-heparin and basic fibroblast growth factor (bFGF) or endothelial cell growth supplement (ECGS) in order to enhance cell proliferation. Coated specimens were kept in culture conditions for a further seven days. Proliferation of transplanted cells was verified by an increase of activation following 3H-thymidine incorporation, while the maintained metabolic cell activity was demonstrated via Prostacycline (PGI2) measurement. Morphology was evaluated by means of scanning electron microscopy (SEM). As evaluated by the beta-Counter, 7 ng/ml bFGF (288,727 +/- 39,668 counts on day 4) substantially enhanced cell proliferation after seeding, opposed to the stimulation with 30,000 ng/ml ECGS (91,924 +/- 1129 counts on day 4), (p < 0.001). The PGI2 release of transplanted cells was stimulated with 25 microM Na arachidonic acid by the factor 2.6 +/- 0.3 and inhibited with 5 mM acetylsalicylic acid by the factor 0.7 +/- 0.2 on day 4 when compared with the basic level.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed1994

Homograft aortic root replacement for destructive valve endocarditis. The benefit of an in-house homograft bank.

This report concerns the surgical treatment of a 45-year old patient with active staphylococcus-endocarditis of the aortic valve which resulted in an aortic root abscess and consequently in a ventricular aortic discontinuity. A technique of homograft aortic root replacement after removal of all infected and necrotic areas is described. After a six month follow-up, the patient is asymptomatic (New York Heart Association functional class I) and shows no signs of recurrence of endocarditis. This case report makes the benefit of an in-house homograft-bank system obvious.

Abscess↗
PubMed1991

Growth properties of cultured human endothelial cells on differently coated artificial heart materials.

The cultivation of autologous endothelial cells on the blood surface of artificial hearts might prevent their detrimental thromboembolic complications. To investigate the growth characteristics of endothelial cells on theoretically suitable biomaterials, we compared three polyurethanes (Pellethane, Biomer, Enka) and three silicone rubbers (Elastosil, 3145 RTV, Medical Adhesive). All synthetic surfaces were precoated with an extracellular matrix (group 1), fibronectin (group 2), or a glutaraldehyde-preserved cellular matrix (group 3). After the seeding of 2.5 x 10(4)/cm2 human endothelial cells into the various surfaces, primary adherence, growth kinetics, and maintenance of monolayer integrity were studied for 13 days. On the three polyurethanes all precoating procedures resulted in endothelial cell proliferation and the formation of persistent monolayers. In contrast, on silicone rubbers a persistent coverage with a confluent endothelium could be achieved only on the glutaraldehyde-preserved cellular matrix. When endothelial cell growth was quantitatively assessed on all precoating substrates, the glutaraldehyde-preserved cellular matrix proved to be far superior on each of the synthetics (p less than 0.001). These results demonstrate the theoretical feasibility of endothelialization of artificial hearts in vitro. Provided such an endothelium can withstand the mechanical forces within an artificial heart, in vitro endothelialization might contribute to a regained attractiveness of the elective long-term implantation of artificial hearts.

Biocompatible Materials↗
PubMed1990

In situ cannulation, microgrid follow-up and low-density plating provide first passage endothelial cell masscultures for in vitro lining.

A rapid and reliable harvest and culture technique was developed to provide a sufficient number of autologous endothelial cells for the confluent in vitro lining of cardiovascular prostheses. Enzymatic endothelial cell detachment was achieved by the in situ application of collagenase to short vessel segments. This harvest technique resulted in a complete lack of contaminating smooth muscle cells in all of 124 cultures from nonhuman primates and 13 cultures from human adults. The use of a microgrid technique enabled the daily in situ quantification of available endothelial cells. To assess ideal plating densities after passage the population doubling time was continuously related to the cell density. Surprisingly, a low plating density of 1.5 X 10(3) endothelial cells/cm2 achieved 43% shorter cell cycles than the usual plating density of 1.0 X 10(4) endothelial cells/cm2. Moreover, low density plating enabled mass cultures after one single cell passage, thereby reducing the cell damaging effect of trypsin. When the growth characteristics of endothelial cells from five anatomically different vessel sites were compared, the external jugular vein--which would be easily accessible and dispensable in each patient--proved to be an excellent source for endothelial cell cultures. By applying in situ administration of collagenase, low density plating and microgrid follow-up to adult human saphenous vein endothelial cells, 14,000,000 first passage endothelial cells--sufficient for the in vitro lining of long vascular prostheses--were obtained 26.2 days after harvest. (95% confidence interval:22.3 to 32.2 days).

Animals↗
PubMed1989

Human endothelial cell seeding: evaluation of its effectiveness by platelet parameters after one year.

Platelet parameters were assessed in patients after implantation of polytetrafluoroethylene (PTFE) grafts, either nonseeded or seeded with autologous endothelial cells or reversed saphenous vein grafts, during the follow-up period of 1 year. The objective of this investigation was to compare the sensitivity of different noninvasive platelet parameters with the assessment of the result of endothelial cell seeding. Scanning electron microscopic investigation of circulating blood platelets showed a significantly higher incidence of activated platelets in patients with seeded or nonseeded PTFE grafts, compared with patients after reversed vein graft implantation. "Shape-changed" platelets, as well as membrane-perforated thrombocytes, were found exclusively in the circulating blood of patients after seeded or nonseeded PTFE graft implantation, indicative of platelet trauma by the artificial graft surface. Plasma levels of platelet factor IV and beta-thromboglobulin, as well as the uptake of indium-111-labeled platelets, failed to show statistically significant differences after 1 year of follow-up. The similar results for seeded and nonseeded grafts indicate the failure of endothelial cell seeding to induce the development of a nontraumatizing surface, comparable to that of saphenous vein grafts.

Blood Platelets↗
PubMed1988

[Quantitative evaluation of knee joint effusions with high resolution real-time sonography].

In three human cadaver specimens an intraarticular effusion of the knee was simulated by injecting sodium chloride in 10 ml portions. The sonographic appearance and quantification as well as the location of the fluid were evaluated. Effusions of the knee joint are a principal sign for many diseases. Their sonographic evaluation is easy and provides valuable clinical information.

Humans↗