Search PubMed⌕ Search

Biomedical subjects

A Schwarz

Publications and source records attributed to A Schwarz.

At least 73 records · Page 4Linked to original sources
PubMed2000

Biliary and gastric bypass or stenting in nonresectable periampullary cancer: analysis on the basis of controlled trials.

BACKGROUND: The median survival rate of patients with nonresectable periampullary cancer is not much longer than 6-12 mo. Nevertheless, in most incurable patients palliative treatment is necessary, which has to focus on jaundice, pain, and prevention of gastric outlet obstruction. Up to now, debate remains about how to best provide palliative treatment. METHOD: The results of controlled clinical trials and large multicenter studies comparing operative biliary bypass and biliary stent insertion in nonresectable pancreatic tumors are discussed in this review. RESULTS: The initial success rate in palliation of jaundice is similar after endoscopic stent insertion and biliary bypass operation (range: 90-95 %). Morbidity (range: 1 1-36% vs 26-40%) and 30-d mortality (range: 8-20% vs 15-31%) is higher after bypass operation, whereas stent insertion is accompanied by a higher rate of hospital readmission and reintervention because of recurrent jaundice (range: 28-43%) and a later gastric outlet obstruction (up to 17%). CONCLUSION: Endoscopic biliary stent insertion should be performed if there is evidence of hepatic, peritoneal, or pulmonary metastasis formation, in old patients with a high comorbidity, or if the patient has had several laparotomies. Combined biliary and gastric operative bypass procedures should be performed in nonresectable periampullary carcinomas with accompanying gastric outlet obstruction, in the absence of metastatic spread, if a locally advanced tumor is the only reason for incurability, if exploratory laparotomy demonstrates an unresectable tumor, or if endoscopic treatment fails.

Ampulla of Vater↗
PubMed2000

Regulation of the hepatic endothelin system in advanced biliary fibrosis in rats.

The aim of the present study was to analyze the hepatic endothelin system and its regulation in liver cirrhosis due to bile duct obstruction. Wistar rats were subjected for 6 weeks to: 1) sham operation; 2) bile duct obstruction; 3) bile duct obstruction and the selective oral endothelin A receptor antagonist LU 135252; 4) bile duct obstruction and oral silymarin, a hepatoprotective and antifibrotic compound. We determined tissue concentrations of endothelin-1 and big-endothelin-1 by ELISA and the density of both endothelin receptor subtypes in plasma membrane fractions by Scatchard analysis. The hepatic endothelin system in liver cirrhosis due to chronic bile duct obstruction is characterized by a simultaneous up-regulation of both endothelin-1 tissue concentration (7.2 fold compared to sham operation; p<0.001) as well as the density of both endothelin receptor subtypes (ET(A) 7.4-fold, ET(B) 4.9-fold, p<0.001, respectively) suggesting a synergistic activation of the hepatic endothelin system in this rat model of non-inflammatory cirrhosis. Treatment with proven antifibrotic agents such as silymarin or a selective endothelin-A-receptor blocker (LU 135252) did not reduce the activity of the hepatic endothelin system, suggesting that the hepatic endothelin system is not activated by the fibrotic process itself.

Animals↗
PubMed2000

The outcome of acute interstitial nephritis: risk factors for the transition from acute to chronic interstitial nephritis.

BACKGROUND: Acute interstitial nephritis has been known as a complication of mainly streptococcal infection for nearly a century. With the advent of infection control, it became a complication caused by antibiotics and later by other drugs, which might have changed the outcome. To determine risk factors for the development of chronic renal insufficiency, and thus, the transition from acute to chronic interstitial nephritis, we performed a retrospective study of all cases of acute interstitial nephritis found by reviewing 1,068 renal biopsies from 1968 to 1997. METHODS: Patients with permanent and reversible renal insufficiency after acute interstitial nephritis were compared with respect to the causative event, the symptoms, and the clinical and histological findings. Differences between the groups were calculated by applying bi- and multivariate analysis. RESULTS: Acute interstitial nephritis was found in 6.5% of all biopsies (64 patients with 68 episodes of acute interstitial nephritis); it was infection-induced in 10%, idiopathic in 4%, and drug-induced in 85% of the cases (antibiotics in 13 cases, analgesics in 17, non-steroidal anti-inflammatory drugs (NSAIDs) in 16, diuretics in 5, and various other drugs in 7). Renal insufficiency was reversible in 69% and permanent in 31% (12% partially reversible, 19% irreversible). The infection-induced and idiopathic types of acute interstitial nephritis were always reversible. Drug-related acute interstitial nephritis caused permanent renal insufficiency in 36% with a maximum of 56% in NSAID-induced cases. In drug-induced cases, intake of the suspected drug for more than a month prior to diagnosis caused permanent renal insufficiency in 88% and interstitial granuloma in 31%. Multivariate analysis disclosed the following significant features separating the permanent from the reversible renal insufficiency group: patients in the first group had more tubular atrophy in their histology, more chronic use of mixed analgesics and/or NSAIDs, less oliguria or anuria as an acute symptom, fewer antibiotics as causative agents, more interstitial granuloma, more pronounced interstitial cell infiltration in their histology, and more imaging of renal shrinkage. Renal histology had the highest predictive value. CONCLUSION: Today, acute interstitial nephritis is mainly drug-induced. NSAIDs are the most frequent cause of permanent renal insufficiency after acute interstitial nephritis. Clinically, subacute symptoms, a prolonged intake of the suspect drug, and chronic analgesic or NSAID use are related to a more chronic course of interstitial nephritis. In histology, tubular atrophy, interstitial granuloma, and pronounced interstitial cell infiltration indicate chronicity.

Acute Disease↗
PubMed1999

Role of epidermal cell-derived alpha-melanocyte stimulating hormone in ultraviolet light mediated local immunosuppression.

Irradiation of the skin with ultraviolet light (UV) results in profound alterations of both local and systemic immune responses. These effects are largely mediated by soluble mediators released from epidermal cells in response to UV. It is well known that keratinocytes release increased amounts of cytokines upon UV-irradiation. UV-light also induces the release of the proopiomelanocortin (POMC)-derived peptide, alpha-melanocyte-stimulating hormone (alpha MSH), from keratinocytes, and upregulates the expression of POMC mRNA. alpha MSH exerts a variety of immunomodulating and antiinflammatory effects, mainly by virtue of its capacity to alter the function of antigen presenting cells and vascular endothelial cells. Within an in vivo mouse-model, both intravenous and topical application of alpha MSH resulted in inhibiting the induction, eliciting a contact hypersensitivity reaction, and inducing hapten-specific tolerance. These findings indicate that alpha MSH, released in the epidermis after UV irradiation, may contribute to UV-mediated immunosuppression. The therapeutic application of alpha MSH or alpha MSH-derived peptides may prove to be a useful approach for treating inflammatory skin diseases.

Animals↗
PubMed1999

Inhibition of epidermal growth factor-induced interleukin-1beta-converting enzyme expression reduces proliferation in the pancreatic carcinoma cell line AsPC-1.

It is suggested that interleukin-1beta-converting enzyme (ICE) and ICE-related proteases play an important role in programmed cell death (apoptosis). We investigated ICE expression in the human pancreatic carcinoma cell line AsPC-1 after stimulation with epidermal growth factor and found a time-dependent expression of active ICE induced by epidermal growth factor. Interestingly, ICE expression does not lead to apoptosis. Cell cycle analyses revealed that acetyl-Tyr-Val-Ala-Asp-chloromethylketone-specific and acetyl-Ala-Ala-Val-Ala-Leu-Leu-Pro-Ala-Val-Leu-Leu-Ala-Leu-Leu-Ala-Pro-T yr-Val-Ala-Asp-aldehyde-specific cell-permeable inhibitors of ICE significantly reduced the proliferation of AsPC-1 cells, which suggested a positive influence of ICE on the proliferation in human pancreatic carcinoma cells.

Apoptosis↗
PubMed1999

Elevation of intracellular glucosylceramide levels results in an increase in endoplasmic reticulum density and in functional calcium stores in cultured neurons.

Gaucher disease is a glycosphingolipid storage disease caused by defects in the activity of the lysosomal hydrolase, glucocerebrosidase (GlcCerase), resulting in accumulation of glucocerebroside (glucosylceramide, GlcCer) in lysosomes. The acute neuronopathic type of the disease is characterized by severe loss of neurons in the central nervous system, suggesting that a neurotoxic agent might be responsible for cellular disruption and neuronal death. We now demonstrate that upon incubation with a chemical inhibitor of GlcCerase, conduritol-B-epoxide (CBE), cultured hippocampal neurons accumulate GlcCer. Surprisingly, increased levels of tubular endoplasmic reticulum elements, an increase in [Ca(2+)](i) response to glutamate, and a large increase in [Ca(2+)](i) release from the endoplasmic reticulum in response to caffeine were detected in these cells. There was a direct relationship between these effects and GlcCer accumulation since co-incubation with CBE and an inhibitor of glycosphingolipid synthesis, fumonisin B(1), completely antagonized the effects of CBE. Similar effects on endoplasmic reticulum morphology and [Ca(2+)](i) stores were observed upon incubation with a short-acyl chain, nonhydrolyzable analogue of GlcCer, C(8)-glucosylthioceramide. Finally, neurons with elevated GlcCer levels were much more sensitive to the neurotoxic effects of high concentrations of glutamate than control cells; moreover, this enhanced toxicity was blocked by pre-incubation with ryanodine, suggesting that [Ca(2+)](i) release from ryanodine-sensitive intracellular stores can induce neuronal cell death, at least in neurons with elevated GlcCer levels. These results may provide a molecular mechanism to explain neuronal dysfunction and cell death in neuronopathic forms of Gaucher disease.

Animals↗
PubMed1999

Levels of serum neopterin are increased in pancreatic cancer patients and correlate with the prognosis.

UNLABELLED: Neopterin has been recognized as a valid marker for cellular immune activation. Raised neopterin levels indicate the stimulation of macrophages and indirectly T-cell activation. So far no data is available on serum neopterin in pancreatic cancer patients. PATIENTS: In this prospective clinical study serum neopterin values were evaluated in 83 patients with adenocarcinoma of the pancreas (PC), 47 patients with chronic pancreatitis (CP), 8 patients with cystadenocarcinoma (CA) of the pancreas and 24 healthy controls (HC). RESULTS: Serum neopterin was significantly elevated in PC (p < 0. 05) and CA (p < 0.04) as compared to HC. There was no difference found between CP and HC. Pancreatic cancer patients with neopterin levels above 2 pmol/ml had a significantly better survival (p < 0. 05) regardless of stage. In stage III and IV (UICC) this difference was highly significant (p < 0.001). Serum levels of neopterin in resectable patients were also significantly correlated with increased survival and in multivariate analysis proved to be an independent prognostic factor. Neopterin in PC was neither correlated with sex, resectability nor with CA 19/9 and CEA. CONCLUSIONS: Patients suffering from PC who did show activated cellular immune response reflected in elevated neopterin levels above 2 pmol/ml had a significantly better prognosis regardless of tumor stage. In advanced stages elevated neopterin concentrations were significantly associated with increased survival. Cellular immune response seems to influence survival in these advanced stages to a higher degree as expected. These findings underline the possibility for supportive immunotherapy in this patient group.

Adult↗
PubMed1999

Autoantibodies to the glutamate receptor kill neurons via activation of the receptor ion channel.

Antibodies to the glutamate/AMPA receptor subunit 3 (GluR3), are found in a human epilepsy, Rasmussen's encephalitis [RE], and were hypothesized as the major cause for the neuronal loss, chronic inflammatory changes and epileptic seizures characteristic of the disease. To establish the pathogenic potential and mechanism of action of such antibodies, we raised murine antibodies against specific peptides of the GluR3 protein and studied their ability to bind, activate, and kill neurons. Mice were immunized with two GluR3 specific peptides: GluR3A (amino acids 245-274) and GluR3B (amino acids 372-395), and with a scrambled GluR3B peptide for control. High levels of antibodies to each of these peptides were obtained, with no cross reactivity between them. Antibodies to the GluR3B peptide were found to bind to cultured neurons, evoke GluR ion channel activity, and kill neurons. In contrast, antibodies against GluR3A peptide bound to neurons but failed to activate the receptor or kill neurons. Anti-scrambled-GluR3B antibodies had no effect. Both the activation of the GluRs and the neuronal death induced by anti-GluR3B antibodies were blocked by CNQX, a specific glutamate/AMPA receptor antagonist; killing was independent of complement. This indicates a mechanism of excitotoxicity-neuronal death due to over-activation of the receptor, a phenomenon known to be caused by excess of glutamate. Purified anti-GluR3B IgGs retained the neuronal killing capacity, and killing was completely and specifically blocked by preincubation with the GluR3B peptide. Excitotoxic neuronal death induced by anti-GluR3B antibodies took place primarily via apoptosis. Taken together, these results show that antibodies to a specific peptide of the GluR can kill neurons by an excitotoxic mechanism, thus mimicking the effects of excess of glutamate. This is the first example that antibodies can lead to neuronal death in a non-classical complement-independent manner, via activation of a membranal neurotransmitter receptor.

Amino Acid Sequence↗
PubMed1999

[Surgical management of liver rupture].

The management of 178 patients with liver trauma (132 male, 46 female; mean age 34 years (range 3-88) presenting from January 1979 to August 1996 is reviewed. There were 165 cases of blunt trauma and 13 cases of penetrating injury. 110 cases were classified as simple injuries (grade I or II) and 68 cases as complex injuries (grade III to V). The overall mortality was 32% (57 patients). The mortality for true hepatic injury was 15.7%. None of the patients with penetrating injuries died. Mortality was influenced by the type of liver injury and the number of associated injuries. The postoperative complication rate was 55%. The most-frequent postoperative complications related to the hepatic injury were intrahepatic or subcapsular hematoma (12.9%) and postoperative bleeding (9.6%). Intraabdominal abscess formation was seen in 2.8%. Operative therapy for liver injuries depends on the grade of the injury. The majority of liver injuries can be managed by simple techniques, including electrocautery and application of hemostatic agents. In complex injuries hepatotomy, direct vessel ligation, and debridement of necrotic tissue is the method of choice (Pachter's procedure). In non-controlled bleeding, perihepatic picking is a standard method.

Adolescent↗
PubMed1999

Prefrontal enlargement of CSF spaces in agoraphobia: a qualitative CT-scan study.

1. This CT study was designed to assess brain morphology in 21 patients with agoraphobia and 21 normal control subjects matched for age and sex. 2. Internal and external CSF spaces were evaluated by qualitative assessment on a 3-point scale (normal, questionable, abnormal). 3. Patients showed bilateral enlargement of prefrontal CSF spaces (p < .05). The rating abnormal" was given in the left hemisphere to 6 (28.6%) of the patients, to 4 (19%) of the patients in the right hemisphere, but to none (0%) of the normal controls. 4. These findings suggest that alterations in brain morphology are involved in the etiology of agoraphobia.

Adult↗
PubMed1999

Incidence of analgesic nephropathy in Berlin since 1983.

BACKGROUND: Phenacetin was removed from the German market in 1986 and was replaced mainly in analgesic compounds by acetaminophen. Our objective was to examine the effect of this measure on the incidence of analgesic nephropathy in light of the changes in other end-stage renal diseases. METHODS: We therefore compared the proportion of renal diseases in all patients starting dialysis treatment during three 18-month periods: 4/1982-9/1983 (n=57); 1/1991-6/1992 (n=81); and 10/1995-3/1997 (n=76). RESULTS: On the one hand, the proportion of end-stage analgesic nephropathy decreased significantly from 30% in 1981-1982 to 21% in 1991-1992 and 12% in 1995-1997 (P=0.01). On the other hand, type II diabetes increased significantly from 7% to 22% (P=0.01) and 29%, (P=0.001). Using the chi2 distribution test to analyze the frequencies of seven diseases at three different time intervals, however, showed that the changes in renal-disease proportions between 1982-1983, 1991-1992 and 1995-1997 were not significantly independent. There was a significant median age increase from 52 years (CI0.95 44-58) in 1982-1983 to 63 (CI0.95 55-67) in 1991-1992 and 63 (CI0.95 60-66) in 1995-1997 (P=0.003) for all patients starting dialysis but not for those with analgesic nephropathy [59 (55-71) vs 64 (53-67) and 61 (50-72); n.s.]. CONCLUSION: The decrease of end-stage analgesic nephropathy since 1983 may be partially due to the removal of phenacetin from the German market in 1986. However, considering the general increase in numbers of dialysis patients, their higher age and the increased incidence of type II diabetes, the decrease in analgesic nephropathy is not a statistically significant independent variable. Altered admittance policies for dialysis treatment have yielded a new pattern of renal-disease proportion which interferes with changes in the incidence of analgesic nephropathy.

Acetaminophen↗
PubMed1999

Endothelin system-dependent cardiac remodeling in renovascular hypertension.

The aim of the present study was to analyze whether the cardiac endothelin system contributes to cardiac remodeling in rats with 2-kidney, 1 clip (2K1C) renovascular hypertension. The endothelin system seems to be a promising candidate for cardiac remodeling because endothelin (ET)-1 promotes growth of cardiomyocytes in vitro and induces cardiac collagen synthesis. The activity of the cardiac endothelin system was analyzed by measuring cardiac tissue big ET-1 and ET-1 concentrations as well as by estimating the cardiac expression of the ETA and ETB receptors 10 days, 4 weeks, and 12 weeks after the renal artery was clipped. The effects of long-term treatment with ETA, ETB, and combined ETA/ETB receptor antagonists on cardiac hypertrophy, media/lumen ratio of intracardiac arteries, and left ventricular fibrosis were also analyzed. This study demonstrated that the overall left ventricular cardiac endothelin system has a similar activity in the early, middle, and late stages of 2K1C renovascular hypertension compared with sham-operated controls. Fibrosis of the left ventricle and hypertrophy of intracardiac arteries, however, were markedly altered after long-term treatment with endothelin receptor antagonists in a blood pressure-independent manner. These 2 effects are mediated by different subtypes of endothelin receptors. ETA receptor blockade completely normalized the hypertrophy of intracardiac arteries (P<0. 01 compared with 2K1C without treatment) in renovascular hypertension, whereas the ETB antagonist reduced cardiac fibrosis of the left ventricle (P<0.001 compared with 2K1C without treatment) to baseline values. This study demonstrates that the cardiac endothelin system plays an important role in the development of cardiac fibrosis as well as in hypertrophy of intracardiac arteries in 2K1C renovascular hypertensive rats.

Animals↗
PubMed1999

Tonsillectomy does not prevent a progressive course in IgA nephropathy.

BACKGROUND: IgA nephropathy, or Berger's disease, is a primary mesangioproliferative glomerulonephritis, usually with a favourable prognosis. PATIENTS AND METHODS: To investigate the effect of tonsillectomy we conducted a retrospective investigation on renal outcome in 55 patients with IgA nephropathy in an outpatient university clinic between 1968 and 1994. Established risk factors for progressive IgA nephropathy were equally distributed in 16 patients subjected to tonsillectomy and in 39 patients without tonsillectomy. Renal survival and impact of risk factors were estimated by Kaplan-Meier analysis and Cox regression model. RESULTS: Seen in terms of the bivariate Kaplan-Meier analysis the probability of renal survival 10 years after biopsy was 0.37 for the 16 patients with tonsillectomy and 0.63 for the 39 patients without tonsillectomy (log-rank test p = 0.49, not significant). In the multivariate Cox regression model with 6 independent clinical covariates, initially high serum creatinine concentration had the strongest impact on renal outcome (p = 0.002), with a hazard ratio of 8.9 (95% CI: 2.3-35.0). Tonsillectomy had no significant influence in the Cox model (p = 0.37), displaying a hazard ratio of 1.7 (95% CI: 0.5-5.7). CONCLUSION: In conclusion, tonsillectomy does not reduce the risk of developing renal failure or prevent a progressive course of IgA nephropathy.

Adult↗
PubMed1999

[Is a Whipple operation in chronic pancreatitis still a current procedure?].

Until the eighties, the surgical procedure of choice in chronic pancreatitis with an inflammatory mass in the head of the pancreas has been partial duodenopancreatectomy (pDP). Since neither stomach, duodenum nor the common bile duct are directly involved in the inflammatory process of the pancreas, the Whipple's procedure (pDP) might lead to overtreatment. Therefore, duodenum-preserving pancreatic head resection (DPPHR), developed by Beger in 1972, has become in several centers the standard procedure for patients with an inflammatory enlargement of the head of the pancreas. We reviewed the literature of the last ten years and evaluated the different surgical procedures for pancreatic head resection. Comparing pDP and DPPHR. Whipple procedure has a higher hospital mortality (3.2% versus 0.6%), a higher late mortality (22% versus 8.4%), a higher morbidity and a higher incidence of a new "surgical" diabetes (17.6% versus 2%). With regard to relief of pain long-term investigations show totally pain-free patients after pDP in 72%, after pylorus-preserving duodenopancreatectomy (PPDP) in 82% and after DPPHR in 89%. Furthermore, other disadvantages of PPDP are the high rate of gastric outlet dysfunction (17% on average with a range of 4-32%) and the high rate of marginal ulcers (8.4% on average with a range of 5-11%). In summary, we conclude that in patients with chronic pancreatitis and an inflammatory enlargement of the pancreatic head. DPPHR is the procedure of choice. Whipple's procedure should only be performed if a suspicion of malignancy is suspected or, secondly, if a patient suffers from persistent pain (5%) after DPPHR.

Chronic Disease↗
PubMed1999

[Pouch stomach reconstruction after gastrectomy].

Up to now there is no general agreement on the ideal reconstruction after total gastrectomy. The importance of the duodenal passage, the need for a pouch reconstruction, and the ideal pouch volume are matters of controversy. Prospective randomized trials show a significantly better quality of life, a higher body weight and a better glucose regulation in patients with a curative operation and good life expectancy, if the duodenal passage is preserved. Reconstruction with a small jejunal pouch offers a better reservoir, less reflux and a better nutritional passage, but a statistically significant improvement of life quality could not be demonstrated up to now. Nevertheless, patients with a curative resection should undergo pouch reconstruction with preservation of the duodenal passage. If curative resection is not possible, reconstruction can be performed according to Hunt-Lawrence-Rodino. The Roux-en-Y-reconstruction without pouch should only be performed in high-risk patients and in carcinoma of the cardia with intrathoracic anastomosis. Nevertheless, further prospective randomized studies with more patients and more specific tests to measure life quality are necessary to evaluate the importance of a jejunal pouch in patients with a preserved duodenal passage.

Anastomosis, Roux-en-Y↗
PubMed1999

Hypercalcemia-induced renal insufficiency during therapy with dihydrotachysterol.

During vitamin-D therapy drug accumulation and intoxication should be considered. In the present study we report on five patients with renal insufficiency during therapy with dihydrotachysterol or calcitriol. Four patients received dihydrotachysterol for 29 (7-44) years and one patient received calcitriol for 4 years to treat hypoparathyroidism after thyroid surgery. As confirmed by renal biopsy impairment of renal function was due to calcifications as a consequence of prolonged hypercalcemia. The effective duration of dihydrotachysterol is ten days as compared with five days for calcitriol. Severe hypercalcemic episodes with dihydrotachysterol are longer-lasting than those with the shorter acting vitamin-D derivatives. Further, they occur with higher incidence as was shown by our own observations and previously published data by other workers. Hence, impairment of renal function during therapy with dihydrotachysterol should be considered as being due to hypercalcemia and hypercalciuria.

Aged↗