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Biomedical subjects

D Lorenz

Publications and source records attributed to D Lorenz.

At least 19 recordsLinked to original sources
PubMed2000

Laparoscopic hernioplasty versus conventional hernioplasty (Shouldice): results of a prospective randomized trial.

The results of our randomized trial of 176 patients comprising primary hernias [Shouldice versus transabdominal preperitoneal approach (TAPP)] showed only slight advantages for the laparoscopically operated group compared to the conventionally operated group: less subjective pain (significant only on fifth postoperative day, p < 0.05), reduced analgesic requirement (significant only on third postoperative day, p < 0.05), significantly shorter duration of hospitalization (4 days vs. 6 days, p < 0.05) and faster return to work (27 days vs. 34 days, NS). Regarding the incidence of recurrences, there was no significant difference between the groups (two recurrences vs. one recurrence) within a follow-up period of 2 years. Postoperative morbidity was similar and the total cost was less for the TAPP group.

Female↗
PubMed1999

[Surgery of stomach carcinoma--established and controversial procedures. Retrospective 1-year analysis with discussion of current aspects].

BACKGROUND: Current problems in gastric cancer surgery concern the extent of gastric resection, the need for abdominal evisceration, the degree of lymphadenectomy, and optimal preoperative tumor staging procedure. PATIENTS AND METHODS: In a restrospective analysis, data on epidemiology, extent of surgery, histopathology, postoperative complications, mortality, and survival in 284 gastric cancer patients were evaluated. RESULTS: Our results are in favor of subtotal gastrectomy performed for all T stages located in the distal or middle third, provided that a tumor-free margin of 5 cm in intestinal type and 10 cm in diffuse Lauren's type tumor can be achieved. Additional organ resections are indicated only if direct tumor invasion has occurred, and should not be part of an extended lymphadenectomy procedure. The degree of lymph node removal should be guided by the primary tumor site. Multimodal therapeutic approaches and high postoperative mortality after exploratory laparotomy justify the use of diagnostic laparoscopy in T3/4 tumors and if diagnostic scans suggest possible tumor spread. CONCLUSION: Even though surgery for gastric cancer is well standardized, a tailored surgical approach to different extent of gastric cancer appears warranted.

Adult↗
PubMed1999

Donor catecholamine use reduces acute allograft rejection and improves graft survival after cadaveric renal transplantation.

BACKGROUND: Epidemiological data implicate that renal transplants from living unrelated donors result in superior survival rates as compared with cadaveric grafts, despite a higher degree of human lymphocyte antigen (HLA) mismatching. We undertook a center-based case control study to identify donor-specific determinants affecting early outcome in cadaveric transplantation. METHODS: The study database consisted of 152 consecutive cadaveric renal transplants performed at our center between June 1989 and September 1998. Of these, 24 patients received a retransplant. Donor kidneys were allocated on the basis of prospective HLA matching according to the Eurotransplant rules of organ sharing. Immunosuppressive therapy consisted of a cyclosporine-based triple-drug regimen. In 67 recipients, at least one acute rejection episode occurred during the first month after transplantation. They were taken as cases, and the remaining 85 patients were the controls. Stepwise logistic regression was done on donor-specific explanatory variables obtained from standardized Eurotransplant Necrokidney reports. In a secondary evaluation, the impact on graft survival in long-term follow-up was further measured by applying a Cox regression model. The mean follow-up of all transplant recipients was 3.8 years (SD 2.7 years). RESULTS: Donor age [odds ratio (OR) 1.05; 95% CI, 1.02 to 1.08], traumatic brain injury as cause of death (OR 2.75; 95% CI, 1.16 to 6. 52), and mismatch on HLA-DR (OR 3.0; 95% CI, 1.47 to 6.12) were associated with an increased risk of acute rejection, whereas donor use of dopamine (OR 0.22; 95% CI, 0.09 to 0.51) and/or noradrenaline (OR 0.24; 95% CI, 0.10 to 0.60) independently resulted in a significant beneficial effect. In the multivariate Cox regression analysis, both donor treatment with dopamine (HR 0.44; 95% CI, 0.22 to 0.84) and noradrenaline (HR 0.30; 95% CI, 0.10 to 0.87) remained a significant predictor of superior graft survival in long-term follow-up. CONCLUSIONS: Our data strongly suggest that the use of catecholamines in postmortal organ donors during intensive care results in immunomodulating effects and improves graft survival in long-term follow-up. These findings may at least partially be explained by down-regulating effects of adrenergic substances on the expression of adhesion molecules (VCAM, E-selectin) in the vessel walls of the graft.

Acute Disease↗
PubMed1999

HLA-DR expression in acute pancreatitis.

OBJECTIVE: To investigate the role of the monocyte/macrophage system in acute pancreatitis DESIGN: Prospective clinical study SETTING: University clinic, Germany SUBJECT: 37 consecutive patients who presented with acute pancreatitis. MAIN OUTCOME MEASURE: Correlation between function of monocytes measured by HLA-DR expression and outcome RESULTS: Patients were divided into three groups according to outcome: those with severe pancreatitis who died (n = 10), those with severe pancreatitis who survived (n = 15), and those with mild pancreatitis who survived (n = 12). There was a clear and significant difference between those with severe and those with mild disease. HLA-DR expression was initially depressed in both groups, but after the third day of treatment it started to recover significantly in those with mild disease (p < 0.05). The difference was also significant from day 7 onwards between those with severe disease who died and those with severe disease who survived (p < 0.05). CONCLUSION: Monocyte function as measured by HLA-DR expression (CD14+DR+) is reduced in patients with acute pancreatitis and does not recover in patients who are going to die (median < 20 relative antigen density units; RU).

Adult↗
PubMed1998

Polarized cell surface expression of the green fluorescent protein-tagged vasopressin V2 receptor in Madin Darby canine kidney cells.

We have analyzed the polarized cell surface expression of the G protein-coupled vasopressin V2 receptor (V2 receptor) in Madin-Darby canine kidney (MDCK) epithelial cells by both conventional cell surface biotinylation assays and laser scanning microscopy of green fluorescent protein (GFP)-tagged receptors. Cell surface biotinylation assays with stably transfected filter-grown cells expressing alkaline phosphatase (PhoA)-tagged receptors demonstrated that the V2 receptor is located predominantly basolaterally at steady state, while minor amounts are expressed apically. Laser scanning microscopy of filter- and glass-grown MDCK cells stably transfected with a GFP-tagged V2 receptor confirmed that the receptor is expressed mainly basolaterally; within the basolateral compartment, however, the receptor was confined to the lateral subdomain. The results obtained with the GFP-tagged receptor are thus consistent with and refine those from the biotinylation assay, which does not discriminate lateral from basal membrane regions. Our data indicate that the GFP methodology may effectively supplement cell surface biotinylation assays in future studies of polarized receptor transport. We finally show that microinjection of a plasmid encoding the GFP-tagged V2 receptor into the nucleus of MDCK cells led to the same results as experiments with stably transfected cells. However, since there was no need for selecting stably transfected cell lines, the experiments were complete within hours. The microinjection technique thus constitutes a powerful single cell technique to study the intracellular transport of G protein-coupled receptors. The methodology may be applicable to any cell type, even to tissue-derived, primary cultured cells; coinjection of transport-regulating compounds should also be possible.

Alkaline Phosphatase↗
PubMed1998

Effect of surgeon expertise on the outcome in primary hyperparathyroidism.

BACKGROUND: Success in surgery for primary hyperparathyroidism (PHPT) is thought to be closely linked to surgical expertise. We investigated the effect of the surgeon's experience on the postoperative outcome in patients with PHPT. DESIGN: Cohort study with retrospective analysis. SETTING: University tertiary care center. PATIENTS: Two hundred thirty consecutive patients with PHPT. We excluded patients with prior cervical surgery, parathyroid carcinoma, multiple endocrine neoplasia types 1 and 2, and renal hyperparathyroidism. INTERVENTIONS: All 230 patients underwent bilateral neck exploration for PHPT. MAIN OUTCOME MEASURES: We registered complication rates, fulfillment of predefined operative concepts, and operative time in 230 cervical revisions for PHPT and compared the results of experienced surgeons (40 or more cervical revisions for PHPT performed before 1988) with those of surgeons still in training. RESULTS: Two surgeons classified as experienced operated on 75 patients. Under supervision of these surgeons, most operative procedures (n=155) were performed by 12 different surgeons classified as less experienced. Complications were observed in 31 patients (13.5%) with no statistical difference between the specialists and the less-experienced surgeons (P=.85). The ability to demonstrate 4 or more parathyroid glands was significantly increased for the specialists (74.7% vs 51.6%; P<.001), who also terminated the operation earlier (average, 15 minutes; P<.001). CONCLUSION: In an analysis of 230 operations for PHPT in patients without prior neck surgery, no effect of the surgeon's experience on postoperative outcome was demonstrated. Under the supervision of experienced endocrine surgeons, less-experienced surgeons perform cervical revisions for PHPT with comparable results, although with longer operating time.

Adolescent↗
PubMed1998

[Cavernous hemangioma of the rectum--a rare cause of peranal hemorrhage].

We report the case of a 34-year-old woman with severe rectal bleeding since the age of 17. The cause of the bleeding was a cavernous haemangioma of the rectum. The extent of the disease was not realised for many years. Sclerosing injections, laser coagulation and even suture ligation were helpful in acute bleeding episodes but did not result in definitive healing. Finally cure was achieved by resection of the rectum and colo-anal sleeve anastomosis. The clinical presentation and the management are described and discussed.

Adult↗
PubMed1998

Correlation between mitotic and Ki-67 labeling indices in paraffin-embedded carcinoma specimens.

The mitotic index (MI) and the Ki-67 labeling index (LI) are both understood to measure cellular proliferation, but their relationship is poorly defined. We determined the mitotic index in hematoxylin and eosin-stained paraffin sections of 189 consecutive carcinomas and performed immunohistochemistry on sections from the corresponding blocks using the Ki-67-specific monoclonal antibody Ki-S5. The distributions of MI and LI in the entire series were clearly different, the former fitting a Poisson function in contrast to a broad-tailed unspecific distribution of the latter. Both indices were closely correlated in mammary carcinomas and non-small cell lung cancers, and to a slightly lesser extent in colorectal adenocarcinomas. No significant association was found in small cell lung cancers. In squamous cell carcinomas, the two parameters were inversely correlated. A good agreement between MI and LI values was observed in well-differentiated and moderately well-differentiated cancers regardless of their histological type, whereas in poorly differentiated carcinomas the correlation was not significant. We conclude that MI and LI measure different proliferation characteristics. Their relationship appears to depend on the tumor type and the degree of differentiation. Rather than artifacts due to processing or evaluation techniques, specific differences in cell cycle kinetics are likely to account for these discrepancies.

Carcinoma↗
PubMed1998

Mechanism of peptide-induced mast cell degranulation. Translocation and patch-clamp studies.

Substance P and other polycationic peptides are thought to stimulate mast cell degranulation via direct activation of G proteins. We investigated the ability of extracellularly applied substance P to translocate into mast cells and the ability of intracellularly applied substance P to stimulate degranulation. In addition, we studied by reverse transcription--PCR whether substance P-specific receptors are present in the mast cell membrane. To study translocation, a biologically active and enzymatically stable fluorescent analogue of substance P was synthesized. A rapid, substance P receptor- and energy-independent uptake of this peptide into pertussis toxin-treated and -untreated mast cells was demonstrated using confocal laser scanning microscopy. The peptide was shown to localize preferentially on or inside the mast cell granules using electron microscopic autoradiography with 125I-labeled all-D substance P and 3H-labeled substance P. Cell membrane capacitance measurements using the patch-clamp technique demonstrated that intracellularly applied substance P induced calcium transients and activated mast cell exocytosis with a time delay that depended on peptide concentration (delay of 100-500 s at concentrations of substance P from 50 to 5 microM). Degranulation in response to intracellularly applied substance P was inhibited by GDPbetaS and pertussis toxin, suggesting that substance P acts via G protein activation. These results support the recently proposed model of a receptor-independent mechanism of peptide-induced mast cell degranulation, which assumes a direct interaction of peptides with G protein alpha subunits subsequent to their translocation across the plasma membrane.

Animals↗
PubMed1998

Impact of renal cadaveric transplantation on survival in end-stage renal failure: evidence for reduced mortality risk compared with hemodialysis during long-term follow-up.

Despite a superior quality of life and a favorable cost effectiveness, it has not been well established thus far whether renal cadaveric transplantation contributes to superior survival probability of end-stage renal disease patients in Europe, because the mortality rate on dialysis is lower compared with the United States. This analysis was undertaken to compare the mortality of wait-listed patients and transplant recipients during long-term follow-up, including the possibility of a retransplant in a single-center study. The study cohort included 309 consecutive patients, ages 17 to 72 yr, being registered on the waiting list of the Renal Transplantation Center of Mannheim since the initiation of the transplantation program on June 3, 1989. Follow-up was terminated on September 30, 1997, with a mean of 4.15 yr. A total of 144 renal cadaveric transplants (four retransplants) was performed during the follow-up period. A Cox regression model considering the time-dependent exposure to the different therapy modalities was applied for statistical analysis. Patients being removed from the waiting list or coming back to dialysis after transplantation were censored at time of withdrawal or graft failure. Transplantation resulted in a lower hazard ratio, which was 0.36 (95% confidence interval, 0.15 to 0.87) when the hazard of the wait-listed group was taken as 1.00. The underlying incidence rate of death was 0.026 per patient-year (0.032 on dialysis versus 0.016 with functioning graft). Performing the evaluation on an intention-to-treat basis without censoring the lower risk of the transplanted group was still pronounced according to a hazard ratio of 0.44 (95% confidence interval, 0.22 to 0.89). Thus, patients receiving a renal cadaveric transplantation have a substantial survival advantage over corresponding end-stage renal disease patients on the waiting list even in the setting of a single transplantation center where mortality on regular dialysis therapy was comparatively low.

Adolescent↗
PubMed1998

[Breast reconstruction-plasty. A modification of the Strömbeck-Wise technique].

We report about 7 patients with an modification of Strömbeck-Wise-technique in reduction mammoplasty. The average weight of reduced breast tissue was about 650 g per side. The experience of this method shows an procedure without complications, with good plastic results and an successful intraoperative symmetry adaptation.

Adult↗
PubMed1998

[Diagnosis and therapy of traumatic injury of the pancreas].

Traumatic injuries of the pancreas are with 3 to 12% of all abdominal traumas an uncommon finding. Intraabdominal combined injuries and unspecific symptoms make an early detection often difficult. In the present study we report on 25 cases (4.7%) with pancreatic trauma out of 529 abdominal injuries that were treated between 1973 and 1996. In 68% of the cases, we detected simple gland lesions with an A.A.S.T.-score I-III (American Association for the Surgery of Trauma). In 32% of the cases, we found extended ruptures of the head of the gland (score IV and V). These patients presented severe therapeutic problems. 98% of our patients had combined intraabdominal injuries. With respect to imaging techniques, CT-scan and ERCP were the most sensitive procedures. Our therapeutic management included in 14 of the cases external drainage after debridement, 6 pancreatic head--and 3 left resections. 2 patients had to undergo a duodenopancreatectomy. The morbidity in our study was 33% (8 patients), whereas septic complications were most often encountered. The clinical mortality was 24% (6 patients). Based on our results, simple drainage after selective debridement may be sufficient for simple gland contusions. For the treatment of severe damages of the pancreatic head, including lesions of the pancreatic or bile duct or duodenum, adequate resection methods are recommended. An early diagnosis is mandatory facilitated by regular employment of CT-scanning and ERCP techniques.

Abdominal Injuries↗