Search PubMed⌕ Search

Biomedical subjects

S Jonas

Publications and source records attributed to S Jonas.

At least 55 records · Page 3Linked to original sources
PubMed2001

Comparative sequence analysis of the core- and NS5-region of hepatitis C virus from tumor and adjacent non-tumor tissue.

The sequence variability within the core- and non-structural 5 (NS5)-region of the hepatitis C virus (HCV) was investigated in tumor and non-tumor tissue of 8 patients with HCV-associated hepatocellular carcinoma (HCC). Analyses of multiple clones containing polymerase chain reaction-amplified HCV sequences revealed a significantly higher variability within the core-region of tumor tissue isolates than of isolates from non-tumor tissue. Mutant sequence diversity ranged from silent mutations, as well as amino acid substitutions, appearance of in frame stop codons and deletions leading to frame-shifts. In contrast, the variability of the NS5-region sequences between isolates from tumor and non-tumor tissue was not significantly different. These observations might have important implications on the pathology of HCV, especially its potential tumorigenicity.

Aged↗
PubMed2000

Enoxaparin, a low molecular weight heparin decreases infarct size and improves sensorimotor function in a rat model of focal cerebral ischemia.

Possible neuroprotective effects of the low molecular weight heparin (LMWH) enoxaparin sodium (Lovenox) were evaluated in a rat model of focal ischemia. Male Sprague-Dawley rats were subjected to 90 min of occlusion of the right middle cerebral artery using the intraluminal suture method. Enoxaparin at doses of 0, 10 or 15 mg/kg was administered to groups of rats 1, 8, 24 and 32 h after artery occlusion. Motor impairment was evaluated by performance on the traverse beam and accelerating rotarod tests. Animals were sacrificed 48 h after occlusion and brain sections were stained with 2% 2,3,5-triphenyltetrazolium chloride for determination of infarct volume. Forty percent of the rats receiving 15 mg/kg enoxaparin died as a result of intracranial hemorrhage. Untreated rats exhibited large lesions involving the caudate putamen and much of the cortex. In enoxaparin - treated rats the damage was mainly confined to the caudate putamen. The sensorimotor behavior of the 10 mg/kg enoxaparin group was significantly better than that of untreated animals. Motor performance of the survivors in the 15 mg/kg group was poor due to hypoactivity and weakness resulting from excessive bleeding. These results suggest that LMWH may have a neuroprotective function.

Animals↗
PubMed2000

Mechanisms of tolerance induction in second renal allografts of a chronic rejection model.

In a previous experiment we demonstrated the induction of tolerance by the allograft itself. In this model of weak histoincompatibility, second grafts of donor origin replacing chronically rejected first renal allografts were accepted long term. Additionally grafted donor-specific hearts functioned indefinitely while adoptive transfer experiments demonstrated the development of donor-specific transferable tolerance. In the current experiment we compared intragraft gene expression of chronically rejected first and tolerant second grafts by RT-PCR. Second renal allografts of donor origin (F-344) replaced first grafts 2, 4, 8, 12, and 16 weeks after the initial engraftment. No immunosuppression was used during second engraftment. Grafts were followed by serial proteinuria; morphological and immunohistological studies (APAAP/infiltrating cells, ICAM-1, MHC II expression) and competitive RT-PCR analyses (expressed as arbitary units AU/cDNA) for relevant cells and cytokines (CD-3, IFNgamma, IL-10, and IL-4) were assessed by the end of the observation period (16 weeks). Macrophages/monocytes (ED-1+) and T-cells (CD-5 and CD-4+) infiltrated first allografts in high numbers by 12 weeks associated with strong structural signs of chronic graft rejection (ca. 30% arterio- and glomerulosclerosis, tubular atrophy and interstitial fibrosis). Cellular infiltrates in second grafts were prominent, however significantly reduced, while histological changes were minor. At cDNA levels, CD-3 transcripts were elevated in second renal allografts performed 2, 4, and 8 weeks after the initial engraftment while comparable levels were observed when second engraftment was performed after 12 and 16 weeks. Analyses of relevant cytokines demonstrated a TH1/TH2 shift independent from the time interval between first and second engraftment. These results emphasize the role of alloresponsiveness for the development of chronic graft dysfunction. Mechanisms of tolerance induction in our model are associated with a distinct alloresponsive pattern. A crucial role for regulatory T-cells is suggested.

Animals↗
PubMed2000

Hepatoma of the liver--resection or transplantation?

INTRODUCTION: Despite recent advances with techniques of in situ tumor ablation, surgical therapy remains at present the mainstay in the treatment of primary hepatic malignancies. DISCUSSION: After an initial endeavor to establish liver transplantation as a treatment option, especially for unresectable liver tumors, only a few indications, for example early hepatocellular carcinoma in cirrhosis, are currently agreed upon. Other indications, such as peripheral cholangiocarcinoma and hepatocellular carcinoma in non-cirrhotics, have largely been abandoned or are still under debate, as with fibrolamellar carcinoma. Selection of patients suffering from hepatocellular carcinoma in cirrhosis for liver transplantation is still based on tumor size and node number, because the current state of diagnostic imaging fails to reliably predict the most important prognostic parameter: vascular infiltration. Other selection criteria are under investigation. Studies on multimodal therapy are also underway but have not yet demonstrated a benefit.

Bile Duct Neoplasms↗
PubMed2000

Surgery for hilar cholangiocarcinoma--the German experience.

Up to 1989, 581 resections of hilar cholangiocarcinomas had been reported in the world literature by 40 authors, the largest experience originating from Professor Rudolf Pichelmayr's group in Hannover. Over the past decade, other centers in Germany have also adopted the more aggressive surgical approach instead of palliative biliary drainage, or even continued to develop further strategies, as the reported long-term results remained disappointing. In Berlin, we started a program of oncological hepatobiliary surgery in 1988. Since then, 104 patients have undergone resections of hilar cholangiocarcinomas, including 14 patients in whom a procedure combining liver transplantation and partial pancreatoduodenectomy, the so-called extended bile duct resection, was performed. Although the rate of curative resections increased significantly after this procedure, a comparable favorable effect with respect to survival figures was not evident. We observed the highest postoperative 5-year survival rates (59%) in the group of patients who had undergone right trisegmentectomy. Preoperative ipsilateral biliary decompression, i.e., of the remnant lobe, and arterial platinum coil embolization of the lobe to be resected are means to achieve a wider applicability of this method.

Bile Duct Neoplasms↗
PubMed2000

Constitutive activity of the light-sensitive channels TRP and TRPL in the Drosophila diacylglycerol kinase mutant, rdgA.

Mutations in the Drosophila retinal degeneration A (rdgA) gene, which encodes diacylglycerol kinase (DGK), result in early onset retinal degeneration and blindness. Whole-cell recordings revealed that light-sensitive Ca2+ channels encoded by the trp gene were constitutively active in rdgA photoreceptors. Early degeneration was rescued in rdgA;trp double mutants, lacking TRP channels; however, the less Ca2+-permeable light-sensitive channels (TRPL) were constitutively active instead. No constitutive activity was seen in rdgA;trpI;trp mutants lacking both classes of channel, although, like rdgA;trp, these still showed a residual slow degeneration. Responses to light were restored in rdgA;trp but deactivated abnormally slowly, indicating that DGK is required for response termination. The findings suggest that early degeneration in rdgA is caused by uncontrolled Ca2+ influx and support the proposal that diacylglycerol or its metabolites are messengers of excitation in Drosophila photoreceptors.

Animals↗
PubMed2000

Urinary excretion of leukotriene E4 and eosinophil protein X in children with atopic asthma.

Measurement of leukotriene E4 (LTE4) in urine is a noninvasive method for assessing changes in the rate of total body cysteinyl leukotriene production. Eosinophil protein X (EPX) has been used to assess eosinophil activity and monitor inflammation in bronchial asthma. The aim of the study was to look for differences in urinary LTE4 and EPX concentrations between children with stable atopic asthma and healthy controls and to compare asthmatic children with different disease severity. In addition the relationship was evaluated between urinary LTE4 and EPX levels and lung function. LTE4 was also measured (enzyme immunoassay) together with EPX (radioimmunoassay) in urine and lung function tests were carried out in children with mild asthma (steroid-naive) (n=49), moderate to severe asthma (using inhaled steroids) (n=31) and healthy control subjects (n=28). Urinary leukotriene E4 (LTE4) was significantly higher in children with asthma than in controls (median [25-75 percentile] 238.5 (126.5-375.7) SD 191.8 versus 189 (51-253.2) SD 131.7 pg.mg(-1) creatinine; p=0.021). Urinary EPX was also significantly increased in asthmatic children compared with controls (85.5 [64-131.5] SD 76.2 versus 48.5 [43.2-90] 112.1 microg x mmol(-1) creatinine; p=0.006). There were no differences in urinary LTE4 and EPX between the group of mild and the group of moderate to severe asthmatic children. There were significant associations between the urinary LTE4 and intrathoracic gas volume (ITGV), residual volume (RV), forced expiratory volume in one second (FEV1), forced expiratory capacity (FVC) and maximum expiratory flow rate at 25% of vital capacity (MEF25). Urinary EPX was only correlated with maximum expiratory flow rate at 75% of vital capacity (MEF75). Thus measurement of urinary LTE4 may predict the degree of airflow obstruction in asthmatic children. Urinary LTE4 and EPX are useful markers of airway inflammation and can be helpful in guiding asthma management. There was no correlation between LTE4 and EPX levels.

Allergens↗
PubMed2000

Liver transplantation and diabetes mellitus.

Post-transplant diabetes mellitus (PTDM) is a common complication after orthotopic liver transplantation (oLT). In our study, we investigated the prevalence and risk factors one year after transplantation in 618 patients who underwent oLT between 1990 and 1996 in a single center. The influence of steroid medication and hepatitis B or C (HBV/HCV) was also studied. Before oLT 66 of the 618 patients were diabetic. After transplantation 37 of these 66 (56%) patients showed no further signs of DM. Of the 552 patients without DM before transplantation 39 (7.2%) developed new onset PTDM. There was no influence of steroid medication on the presence of PTDM (steroids 10.4% PTDM, no steroids 12.5% PTDM). In addition we found no influence of HBV or HCV-infection on PTDM development. Analysis for risk factors showed no significant influence of the diagnosis leading to oLT, of FK506 or Cyclosorin A medication, age, gender or Child-Pugh class. Five year patient survival was not influenced by the presence of PTDM, especially patients with a preexisting DM showed no reduced survival. However, a subgroup of patients with new onset insulin-requiring PTDM showed significantly reduced 5 year survival (p<0.05). In conclusion we found new onset PTDM in 7.2% of patients undergoing oLT one year after the operation. On the other hand in more than 50% of patients with preexisting DM, the disease was no longer present post-transplant. This could be an indication that DM is dependent on liver function in these patients. Patients with preexisting DM should not be excluded from transplantation if indicated. Development of new onset insulin-requiring PTDM could be an important prognostic factor for patient survival after oLT. Further investigations are necessary to evaluate the prognostic meaning of PTDM and the pathophysiologic mechanisms.

Diabetes Mellitus↗
PubMed2000

Prognostic factors in patients with differentiated thyroid carcinoma.

OBJECTIVE: To study the prognostic factors in patients with differentiated thyroid carcinoma. DESIGN: Retrospective analysis. SETTING: University hospital, Germany. PATIENTS: 139 consecutive patients who underwent surgery for follicular (n = 42) and papillary thyroid carcinoma (n = 97). MAIN OUTCOME MEASURES: Survival rate, type of operation (systematic lymphadenectomy or no lymphadenectomy). RESULTS: Median observation time was 72 months (range 1-203). The 5 and 10 year survival rates in patients with papillary carcinoma were 92% and 89% respectively, and in those with follicular carcinoma 88% and 80%, respectively. Prognostic factors for papillary carcinoma were distant metastases, age, and extrathyroidal growth, and for follicular carcinoma they were distant metastases, extrathyroidal extension, and multifocal growth. The Union International contre le Cancer and European Organisation for Research and Treatment of Cancer scores and the age, grade, extent and size score were all highly significant. The extent of lymphadenectomy, primary or secondary thyroidectomy, and partial or total thyroidectomy did not influence survival. CONCLUSION: Staging and score systems may be helpful in calculating prognosis in differentiated thyroid carcinoma, but the benefit of systematic lymphadenectomy remains controversial.

Adenocarcinoma, Follicular↗
PubMed1999

[Lymphoepithelial carcinoma of the extrahepatic bile duct].

A 36-year-old female patient was transferred to our unit for surgical treatment of a biliary tract obstruction. ERC disclosed an obliteration of the common hepatic duct involving the hepatic bifurcation. Primary sclerotic cholangitis and carcinoma of the bile duct could not be confirmed histologically in the biopsy specimens. Tumor markers and autoimmune antibodies were normal. Histological examination of the ductus choledochus during the operation was not conclusive and a malignant lymphoma was considered. The macroscopic appearance comprised obliterative alterations extending to the right hepatic duct. Therefore, resection of the extrahepatic bile duct, right hemihepatectomy and hepaticojejunostomy were performed. The final histological statement revealed a lymphoepithelial carcinoma. The postoperative course of the patient was uneventful, and the patient is in good condition without any signs of recurrent disease 12 months after the operation. This tumor has been described as occurring as a neoplasm of the stomach and salivary glands exclusively and as being of low-grade malignancy. Additional histological evaluations confirmed the diagnosis of lymphoepithelial carcinoma.

Adult↗
PubMed1999

Extended resections for hilar cholangiocarcinoma.

OBJECTIVE: To evaluate different strategies for extended resections of hilar cholangiocarcinomas on radicality and survival. SUMMARY BACKGROUND DATA: Surgical resection of hilar cholangiocarcinoma is the only potentially curative treatment. Resection of central bile duct carcinomas, however, cannot always comply with the general principles of surgical oncology to achieve wide tumor-free margins with no-touch techniques. METHODS: From 1988 to 1998, 95 patients underwent resection of hilar cholangiocarcinoma. Eighty patients had hilar and hepatic resections and 15 had liver transplantation and partial pancreatoduodenectomy (LTPP; i.e., eradication of the entire biliary tract using a no-touch technique). RESULTS: The 60-day death rate was 8%. The overall 1- and 5-year survival rates were 67% and 22%, respectively. Five-year survival rates after R0, R1, and R2 resections were 37%, 9%, and 0%. In a multivariate analysis, surgical radicality was the strongest determinant of survival (p < 0.001). The rate of formally curative resection (R0 resection) was significantly lower in hilar resections (29%) than in liver resections (left hemihepatectomy 59%, right hemihepatectomy 55%, right trisegmentectomy 65%; p < 0.05). The highest rate of R0 resection was observed after LTPP (93%; p < 0.05). Right trisegmentectomies achieved the highest rate of 5-year survival after R0 resection (57%). In a multivariate analysis of patient survival after R0 resection, additional portal vein resection was the only significant factor. The 5-year survival rate after formally curative liver resection with portal vein resection was 65% versus 28% without. CONCLUSION: Extended resections, especially right trisegmentectomies and LTPP, resulted in the highest rate of R0 resection. Right trisegmentectomy together with portal vein resection best represents the principles of surgical oncology and may be regarded as the surgical procedure of choice. Immunosuppression limits the applicability of LTPP.

Aged↗