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Biomedical subjects

K H Dietl

Publications and source records attributed to K H Dietl.

At least 19 recordsLinked to original sources
PubMed2000

Cadaveric "two-in-one" kidney transplantation from marginal donors: experience of 26 cases after 3 years.

BACKGROUND: Because of the problem of organ shortage, the use of renal transplants from marginal donors has been tested by different procedures. METHODS: In our center 26 recipients (59 +/- 7 years) underwent double renal transplantation from July 1996 to August 1999 using marginal donors (71 +/- 6 years). A special scoring was applied that included donor age, serum creatinine, the grade of glomerulosclerosis, and kidney weights leading to the decision whether single or dual or no kidney transplantation was performed. RESULTS: After an average follow-up of 18 +/- 10 months 22 of 26 (85%) double kidney transplant recipients are alive and have functioning grafts. Three patients died with well-functioning grafts. The actuarial 1-year patient and graft survival rate was 94% (n=18), the 2-year rate 92% (n=12). Two patients lost one graft each without becoming dialysis dependent. The average serum creatinine was 1.6 +/- 0.5 mg/dl after 12 months (n=17) and 1.9 +/- 0.6 mg/dl after 24 months (n=11). Primary nonfunction occurred in 31%, acute rejection within the first 6 months in 14%. Ten patients who received single old grafts according to our score had similar transplant survival rates but worse graft function after 1 year. CONCLUSIONS: Transplant function and survival of patients after dual kidney transplantation indicate that this procedure is reasonable to ameliorate the problem of organ shortage. The most crucial point is to establish a widely accepted standardized scoring for the donors leading to single, dual, or refusal of transplantation.

Aged↗
PubMed2000

Preoperative diagnosis of bile duct strictures--comparison of intraductal ultrasonography with conventional endosonography.

BACKGROUND: The accuracy of intraductal ultrasonography (IDUS) and endoscopic ultrasonography (EUS) were compared in diagnosing biliary obstruction and in predicting surgical resectability. METHODS: Fifty-six patients with biliary obstruction were investigated preoperatively with both conventional EUS and IDUS. The ultrasonographic miniprobe was inserted into the bile duct system through the working channel of the duodenoscope during endoscopic retrograde cholangiopancreatography (ERCP). Conventional endosonography was performed with echoendoscopes in a standard technique. Images of endoluminal ultrasonography were prospectively reviewed and compared with intraoperative findings and resection specimen analyses. RESULTS: IDUS exceeded EUS in terms of accuracy (IDUS, 89.1%; EUS, 75.6%; P < 0.002), sensitivity (IDUS, 91.1%; EUS, 75.7%; P < 0.002), specificity (IDUS, 80%; EUS, 75%; NS), and T-staging (IDUS, 77.7%; EUS, 54.1%; P < 0.001). In bile duct carcinomas the accuracy rate for lymph node staging using IDUS (60%) is comparable with that using EUS (62.5%). In pancreatic carcinomas, however, lymph node staging using IDUS (13.3%) is significantly (P < 0.002) inferior to EUS (69.2%). Endoluminal ultrasonography may predict the potential resectability of bile duct tumors (IDUS, 81.8%; EUS, 75.6%; P < 0.002). CONCLUSIONS: IDUS proved to be accurate in preoperative diagnosing and T-staging of malignant biliary strictures, whereas it is not suitable for lymph node staging. IDUS using miniprobes during ERCP exceeds conventional EUS in terms of depiction of bile duct obstruction, diagnostic accuracy, and sensitivity and in the prediction of surgical tumor resectability. Additionally, different to EUS, IDUS can conveniently be performed during ERCP in one and the same session.

Adult↗
PubMed2000

Measurement of skeletal status after renal transplantation by quantitative ultrasound.

BACKGROUND: Osteoporosis remains a major problem following kidney transplantation. Radiographic measures of bone mass are of limited predictive value after transplantation and are complicated by preexisting renal osteopathy. Quantitative ultrasound (QUS) is a new and non-invasive method to assess skeletal status, however, no data exist on ultrasonic bone parameter after kidney transplantation. We evaluated the potential use of this novel method in renal allograft recipients and studied the accuracy compared to normal controls. METHOD: Thirty patients (NTP, age 47.5 +/- 13.0 years) were studied 4.8 +/- 3.2 years after transplantation. Twenty-five healthy control persons (CON) were matched for age and sex. The left and right os calcis were studied by QUS and speed of sound (SOS) and broadband ultrasound attenuation (BUA) were measured. Bone stiffness (BS) was calculated from these parameters and corrected for age (CBS). Differences between right and left os calcis were compared to CON to assess the side variability. RESULTS: Mean +/- SD BS was 75 +/- 22% compared to young adults, age-corrected CBS was decreased in NTP with 86 +/- 25% of normal, indicating a two-fold increased risk of fracture. SOS was 1525 +/- 47.7 m/s, BUA 105 +/- 22 dB/MHz. Mean difference between right and left os calcis was significantly higher in NTP than in CON (7.2 +/- 7.1% vs. 2.1 +/- 2.1%, p < 0.01). Limits of agreement of the measurements (MW of differences +/- 2 SD) according to a Bland-Altmann-type statistic were -16.9% and 20.7%. There was no correlation between CBS and age, cumulative steroid dose, parathyroid hormone concentrations or time after transplantation. CONCLUSION: Our data show altered bone structure expressed by low bone stiffness values measured by quantitative ultrasound in kidney transplant patients. However, because of relatively high inter-feet variance of QUS results we suggest measurement of both ossa calcis to minimize measurement error after transplantation.

Biomechanical Phenomena↗
PubMed1999

Prognostic value of lymphocyte apoptosis in acute rejection of renal allografts.

BACKGROUND: Apoptosis is a cellular phenomenon generally found within rejecting transplants. It may play a role in physiological or therapy-associated deletion of infiltrating lymphocytes or in graft cell destruction. Our study focuses on apoptosis of infiltrating lymphocytes during acute kidney rejection after the initial steroid pulse therapy and on possible prognostic implications. METHODS: Renal biopsy specimens of 23 transplant recipients with acute tubulo-interstitial rejection were examined for appearance of apoptosis and compared with 11 transplant biopsies with unspecific organ injury accompanied by lymphocyte infiltration. In all patients, biopsies were performed after steroid pulse therapy, and, after confirmation of rejection, antilymphocytic antibody treatment was carried out. Apoptosis was determined via terminal deoxynucleotidyltransferase-mediated dUTP-digoxigenin nick end labeling analysis and confirmed by electron microscopy. RESULTS: Apoptosis of lymphocytes or of tubular epithelium was detected in 11 cases of acute rejection (48%), respectively. Four biopsies showed lymphocytic as well as tubular apoptosis, whereas five sections showed no signs of programmed cell death. In biopsies revealing unspecific injury, tubular cell apoptosis was more frequently found (73%) compared with lymphocyte apoptosis (27%, P<0.05). Most interestingly, patients with a beneficial recovery from acute rejection had a higher proportion of lymphocyte apoptosis compared with patients with poor rejection outcome. The Bcl-2 oncoprotein was widely found within infiltrating lymphocytes without counter-regulating apoptosis. CONCLUSIONS: Lymphocyte apoptosis is found as frequently as tubular cell apoptosis in rejecting renal grafts after steroid pulse therapy and might have prognostic value for rejection outcome.

Acute Disease↗
PubMed1999

Tumors of the papilla of Vater--inadequate diagnostic impact of endoscopic forceps biopsies taken prior to and following sphincterotomy.

BACKGROUND: It has been proposed that adenomas of the papilla of Vater are precursors of adenocarcinomas. Duodenoscopy with ERCP and forceps biopsies have substantially improved the morphologic exploration of the major duodenal papilla. Yet there is little and contradictory information as to the diagnostic accuracy of endoscopic biopsies in tumors of the papilla. Moreover, after endoscopic sphincterotomy data on the diagnostic impact of endoscopic biopsies from the papilla are scarce and, in most cases, retrospectively obtained. Thus, the aim of the present prospective and histopathologically controlled study was to assess the diagnostic accuracy of endoscopic biopsies taken from tumors of the papilla before and after sphincterotomy. PATIENTS AND METHODS: Forty patients with tumors of the papilla of Vater were included in the study. In each case, a comparison was made between endoscopic forceps biopsy diagnoses prior to and following sphincterotomy and the definitive histological diagnosis after surgical tumor resection. RESULTS: Resected tumors were diagnosed histomorphologically as follows: 19 adenocarcinomas (47%), 6 tubular adenomas (15%), 7 villous adenomas (17%), 7 inflammatory non-neoplastic lesions (pseudotumors) (17%), and one adenomyoma (2%). Overall accuracy for preoperative histopathological diagnosis was 62% (25 of 40, 95% CI: 47%-76%) prior to sphincterotomy while it was 70% (28 of 40, 95% CI: 55%-81%) following the procedure. Regarding adenocarcinomas, sensitivity was found to be 21% (4 of 19, 95% CI: 8%-43%) prior to and 37% (7 of 19, 95% CI: 19%-58%) after sphincterotomy while specificity was 100% at both times. CONCLUSIONS: Endoscopic forceps biopsies do not allow for reliable preoperative diagnosis of tumors of the papilla of Vater.

Adenocarcinoma↗
PubMed1998

[Mutilating complex trauma of the pelvis].

Traumatic hemipelvectomy is a rare, but devastating pelvic injury with few survivors reported in the literature. We report on a 19-year-old motorcyclist with a near-total hemipelvectomy. After a complicated course, the patient survived with good potential for a functional level of activity. We review the experience of other authors and give details on the management of one of the most challenging injuries confronting surgeons. Successful treatment requires extraordinary efforts and multidisciplinary team cooperation.

Adult↗
PubMed1997

[Magnetic resonance tomography without and with gadolinium-DTPA for evaluating kidney transplants].

PURPOSE: To determine the value of MR imaging in differentiating the various causes of human renal allograft dysfunction. METHODS: A total of 123 human renal allografts (normal n = 20, acute rejection n = 57, acute tubular necrosis n = 14, interstitial fibrosis n = 11, chromic allograft glomerulopathy n = 11, cyclosporine nephrotoxicity n = 3, cortical necrosis n = 7) were investigated by means of MR imaging. Axial T1-weighted spin-echo images and coronal T1-weighted gradient-echo images were obtained before and after Gd-DTPA injection. Diagnostic parameters included corticomedullary contrast and allograft size and shape on the pre-contrast sequences. RESULTS: None of the diagnostic parameters used could differentiate among the various diagnostic groups. Diagnostic of cortical necrosis could be made only on post-contrast scans. Contrast-enhanced scans were superior to pre-contrast images in detection of focal allograft lesions. Otherwise, contrast-enhanced scans did not provide any more information than pre-contrast studies. Spin-echo and gradient-echo sequences displayed the same diagnostic value. CONCLUSIONS: MR imaging has a limited value in differentiating the various causes of renal allograft dysfunction.

Adult↗
PubMed1997

Decreased cellular Mg2+ concentrations in a subgroup of hypertensives--cell models for the pathogenesis of primary hypertension.

A new method to determine total Mg2+ content in lymphocytes was developed, offering advantages for routine measurements as compared to fluorescence methods. Intracellular Mg2+ measurements were performed in lymphocytes of 18 untreated normotensive and 19 untreated essential hypertensive patients. Mg2+ content was referred to lymphocytic protein, which was determined according to Bradford's method. Mg2+ measurements were performed by atomic absorption spectroscopy using a Video 12 apparatus from Thermo Electron Instrumentation Laboratory, Andover, MA, USA. The results show that in patients with essential hypertension, total intralymphocytic Mg2+ content is significantly lower (0.07 +/- 0.05 mmol/g lymphocytic protein, mean +/- s.d.) as compared to controls (0.11 +/- 0.04 mmol/g lymphocytic protein, mean +/- s.d., P < 0.05). Free intracellular Mg2+ content was measured in lymphocytes by the fluorescent indicator mag-fura-II, showing no significant difference in normotensives and hypertensives (0.30 +/- 0.16 vs 0.38 +/- 0.17 mmol/l). In platelets free intracellular Mg2+ concentrations were not found of significant difference in normotensive and hypertensive patients (0.52 +/- 0.23 vs 0.47 +/- 0.27 mmol/l) using mag-fura-II. In plasma Mg2+ concentrations there was no significant difference in the normotensive and hypertensive group (0.92 +/- 0.07 vs 0.88 to 0.07 mmol/l). There was no correlation between plasma, free or total cellular magnesium concentrations in each group. Furthermore this method also seems suitable for routine measurements of total intracellular Mg2+ concentrations in even larger groups of patients in comparison with fluorescent indicator measurements like mag-fura-II. Lowered total intracellular Mg2+ concentrations in a subgroup of primary hypertension may contribute to the development of this disorder, perhaps due to different buffering systems.

Adult↗
PubMed1997

The heart muscle's putative "secondary structure'. Functional implications of a band-like anisotropy.

Opinions are divided as to whether the rope-like secondary structure, which Torrent-Guasp dissected out of the myocardial body by the blunt unwinding technique (BUT) reveals some kind of functional compartmentation of the heart muscle. The myocardial fibres are aligned parallel to the fibre disruption (cleavage) plane, along which the band has been prepared but they are not necessarily aligned parallel to the long axis of the band. Inconsistencies in the myocardial rope model arise from the obligatory zones of transmural inflection, which are obvious in the base and the apex of both ventricles. They are, however, merely discernible in the midzone of the left ventricular cone. The investigator experienced in BUT knows that the cleavage plane is not unique. We doubt the assumption that the rope structure is the predominant stress transmission pathway, because the fibre strand peel-off technique (SPOT) delivers irregular fibre disruption planes which are definitely different from those which Torrent-Guasp prepares. The rope-like fibre arrangement could be just a redundant structure, a remnant of past developmental steps without, however, any functional implication to the human heart. On the other hand, peeling-off fibre strands from the ventricular wall produces deeply perforating, i.e., oblique transmurally grooved surfaces. Putative functions of force transmission in an oblique transmural direction are (1) ventricular dilation as a function of the variable inclination angle with respect to the epicardial surface, (2) monitoring of ventricular wall stress and ventricular size and (3) segmental stiffening which could serve other dependent segments as a punctum fixum.

Anisotropy↗
PubMed1997

The heart's fibre alignment assessed by comparing two digitizing systems. Methodological investigation into the inclination angle towards wall thickness.

Myocardial contractile pathways which are not aligned strictly parallel to the heart's epicardial surface, give rise to forces which also act in the ventricular dilating direction. We developed a method which allows us to assess any fibre orientation in the three-dimensional myocardial weave. Decollagenized hearts were prepared by peeling-off fibre strands, following their main fibre orientation down to near the endocardium. In the subepicardium the strands followed a course more or less parallel to the epicardium, whereas from the mid-wall on they tended to dive progressively deeper into the wall. The preparation displays more or less rugged surfaces rather than smooth layers. The grooves and crests on the exposed surfaces were sequentially digitized by two methods: (1) Using a magnet tablet (3 Draw Digitizer System, Polhemus, Cochester VTO 5446, USA) on a dilated pig heart we manually followed the crests using a stylus, handling each groove and crest as an individual contractile pathway. (2) A constricted cow heart was digitized using a contact-free optical system (opto TOP, Dr. Breuckmann, Meersburg, Germany), which is based on the principle of imaging triangulation. Using specially developed software the inclination angles of selected crests and grooves with respect to the epicardial surface were calculated. The two digitizing methods yield comparable results. We found a depth- and side-specific weave component inclined to the epi-endocardial direction. This oblique netting component was more pronounced in the inner 1/3 of the wall than in the subepicardium. The inclination angle probably increases with increasing wall thickness during the ejection period. Manual digitizing is an easy and fast method which delivers consistent results comparable with those obtained by the cumbersome high resolution optical method. The rationales for the assessment of transmural fibre inclination are (1) the putative existence of dilating forces inherent in the myocardial weave and (2) the possible overproportional increase in the oblique transmural weave component during myocardial hypertrophy, which would entail a reduction in efficiency of ventricular performance in terms of haemodynamic work.

Animals↗
PubMed1997

The assessment of intramural stress alignment on the beating heart in situ using micro-ergometry: functional implications.

The main local stress transmission pathways in the left ventricular base, midportion and apex in up to seven layers have been assessed in normal dog and porcine hearts, in hypertrophied dog hearts, and in three pig hearts having undergone a temporary left ventricular outflow stricture. The rotational sensitivity of needle force probes was used to determine the focal surface-parallel direction of the myocardial tension vector. In all places investigated the orientation of the force transmission pathways differs slightly from the morphologically determined fibre alignment. Vector rotation upon an axis normal to the epicardial surface is definitely tempered as compared to fibre rotation. Alterations in the force transmission pathways assessed in hypertrophied dog hearts by micro-ergometry qualitatively confirm structural remodelling in so far as an irregularity in the transmural rotation of the main stress vector was found. The measured disparities between the alignment of the myocardial fibre weave and the direction of stress transmission both in the normal and the diseased heart is widely individual, and hence, scattering of the data is marked. However, it must also be called into consideration that the measured orientation of force vectors is that at the moment of highest developed force, only. Further investigations will elucidate if discrepancies between that force vector and morphology are less pronounced when the vector is averaged over the entire heart cycle.

Animals↗
PubMed1997

Inhomogeneities in wall stress measured by microergometry in the heart muscle in situ.

Microergometry is a method which we have developed as a tool to measure local mesh-tension within the myocardial weave at any measuring site of both ventricles and the septum on the beating heart in situ. In a mapping procedure on pig and dog hearts, both in control conditions and in the hypertrophied state after aortic banding, local mesh-tension was measured in several areas and in up to eight depths proceeding from the epicardium to the endocardium: Probe-to-fibre coupling is definitely more stable in the canine myocardium than in the porcine heart muscle, probably due to a more effective connective tissue fettering of the canine myocardial weave. The observed longitudinal gradient, with the highest tension in the base, of control dog hearts was levelled out in the hypertrophied hearts. Furthermore, in control dog hearts mesh-tension in the subepi- and subendocardial layers was higher than in the midlayers. This pronounced midlayerhypotension was smoothed in the hypertrophied hearts. Further studies will be dedicated to the question of whether the impact of ventricular size and shape on intersegmental stress transmission is determined by the Frank-Starling mechanism alone or whether protracted remodelling processes on the level of the local fibre weave cause slow coupling alterations.

Animals↗
PubMed1997

Effects of cyclosporin A and FK 506 on lipid metabolism and fibrinogen in kidney transplant recipients.

After allogenic transplantations a dramatic increase in the development of arteriosclerotic plaques can be observed, which might be due to metabolic alterations, influenced by changes of the transplant organ or immunosuppression. In this study the effects of FK 506 in kidney transplant patients on cardiovascular risk factors were compared to cyclosporin A (CsA) immunosuppression. Both groups showed no statistical differences in number, kidney function, age, body weight, sex distribution, steroid dosage and follow-up time after transplantation. Total cholesterol was similar in FK 506-treated patients (231 +/- 22 vs. 278 +/- 52 mg/dl) as compared with patients with CsA immunosuppression. Furthermore, there were no differences in triglycerides (220 +/- 72 vs. 210 +/- 67 mg/dl), HDL-cholesterol (67 +/- 14 vs. 52 +/- 18 mg/dl) and fasting glucose (112 +/- 36 vs. 116 +/- 17 mg/dl). However, the concentration of LDL-cholesterol (114 +/- 21 vs. 167 +/- 37 mg/dl), the independent risk factor Lp(a) (11 +/- 9 vs. 27 +/- 8 mg/dl) and fibrinogen (216 +/- 71 vs. 297 +/- 47) was lower in FK 506-treated patients. Our results indicate that FK 506 immunosuppression offers some advantages in cardiovascular risk factors.

Adult↗