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L Fischer

Publications and source records attributed to L Fischer.

At least 19 recordsLinked to original sources
PubMed2006

Phosphatidylinositol 3-kinase facilitates bile acid-induced Ca(2+) responses in pancreatic acinar cells.

Bile acids are known to induce Ca(2+) signals in pancreatic acinar cells. We have recently shown that phosphatidylinositol 3-kinase (PI3K) regulates changes in free cytosolic Ca(2+) concentration ([Ca(2+)](i)) elicited by CCK by inhibiting sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA). The present study sought to determine whether PI3K regulates bile acid-induced [Ca(2+)](i) responses. In pancreatic acinar cells, pharmacological inhibition of PI3K with LY-294002 or wortmannin inhibited [Ca(2+)](i) responses to taurolithocholic acid 3-sulfate (TLC-S) and taurochenodeoxycholate (TCDC). Furthermore, genetic deletion of the PI3K gamma-isoform also decreased [Ca(2+)](i) responses to bile acids. Depletion of CCK-sensitive intracellular Ca(2+) pools or application of caffeine inhibited bile acid-induced [Ca(2+)](i) signals, indicating that bile acids release Ca(2+) from agonist-sensitive endoplasmic reticulum (ER) stores via an inositol (1,4,5)-trisphosphate-dependent mechanism. PI3K inhibitors increased the amount of Ca(2+) in intracellular stores during the exposure of acinar cells to bile acids, suggesting that PI3K negatively regulates SERCA-dependent Ca(2+) reloading into the ER. Bile acids inhibited Ca(2+) reloading into ER in permeabilized acinar cells. This effect was augmented by phosphatidylinositol (3,4,5)-trisphosphate (PIP(3)), suggesting that both bile acids and PI3K act synergistically to inhibit SERCA. Furthermore, inhibition of PI3K by LY-294002 completely inhibited trypsinogen activation caused by the bile acid TLC-S. Our results indicate that PI3K and its product, PIP(3), facilitate bile acid-induced [Ca(2+)](i) responses in pancreatic acinar cells through inhibition of SERCA-dependent Ca(2+) reloading into the ER and that bile acid-induced trypsinogen activation is mediated by PI3K. The findings have important implications for the mechanism of acute pancreatitis since [Ca(2+)](i) increases and trypsinogen activation mediate key pathological processes in this disorder.

Androstadienes↗
PubMed2006

Prospective trial on topotecan salvage therapy in primary CNS lymphoma.

BACKGROUND: Standard salvage therapy has not been established for recurrent primary central nervous system lymphoma (PCNSL). We report the final results of a prospective study on topotecan chemotherapy in relapsed or refractory PCNSL. PATIENTS AND METHODS: The study included 27 patients with a median age of 51 years and an ECOG performance status of 2. Fourteen patients were refractory to the last therapy, and 13 relapsed after a median period of 6.0 months. Pretreatment with up to four regimens included chemotherapy in 26 patients and whole brain irradiation in 14. A 30-min daily topotecan infusion of 1.5 mg/m(2) for 5 days was repeated every 3 weeks. RESULTS: The response rate was 33% with five complete (CR) and four partial remissions (PR). The median follow-up was 37.7 months. All complete responders had sustained remissions lasting for 9 to 28 months. The median event-free survival (EFS) was 2.0 months (9.1 months in responders), the overall survival (OAS) was 8.4 months. CTC grade 3-4 leukopenia occurred in 26% and thrombocytopenia in 11% of the patients. Eight of 12 patients alive without cerebral lymphoma > or = six months after topotecan exhibited deficits attributable to late neurotoxicity. CONCLUSION: Topotecan as monotherapy is active in relapsed and refractory PCNSL with tolerable toxicity.

Adult↗
PubMed2006

Use of DNA and recombinant canarypox viral (ALVAC) vectors for equine herpes virus vaccination.

In this study, experimental canarypox virus (ALVAC) and plasmid DNA recombinant vaccines expressing the gB, gC and gD glycoproteins of EHV-1 were assessed for their ability to protect conventional ponies against a respiratory challenge with EHV-1. In addition, potential means of enhancing serological responses in horses to ALVAC and DNA vaccination were explored. These included co-administration of the antigen with conventional adjuvants, complexation with DMRIE-DOPE and co-expression of the antigen along with equine GM-CSF. Groups of EHV primed ponies were vaccinated twice intra-muscularly with one dose of the appropriate test vaccine at an interval of 5 weeks. Two to 3 weeks after the second vaccination, ponies were infected intra-nasally with the virulent Ab4 strain of EHV-1 after which they were observed clinically and sampled for virological investigations. The results demonstrated that DNA and ALVAC vaccination markedly reduced virus excretion after challenge in terms of duration and magnitude, but failed to protect against cell-associated viremia. Noteworthy was the almost complete absence of virus excretion in the group of ponies vaccinated with ALVAC-EHV in the presence of Carbopol adjuvant or DNA plasmid formulated with aluminium phosphate. The administration of the DNA vaccine in the presence of GM-CSF and formulated in DMRIE-DOPE and of the ALVAC vaccine in the presence of Carbopol adjuvant significantly improved virus neutralising antibody responses to EHV-1. These findings indicate that DNA and ALVAC vaccination is a promising approach for the immunological control of EHV-1 infection, but that more research is needed to identify the immunodominant protective antigens of EHV-1 and their interaction with the equine immune system.

Adjuvants, Immunologic↗
PubMed2006

Performance of D-amino acid oxidase in presence of ionic liquids.

The activity and stability of free and immobilized D-amino acid oxidase (DAAO, EC 1.4.3.3) from Trigonopsis variabilis CBS 4095 in different water-soluble and water-insoluble ionic liquids (ILs) as well as in organic solvents were studied for comparison. The most promising ILs ([BMIM][BF(4)] and [MMIM][MMPO(4)]) were investigated in detail. The kinetic parameters (v(max) = 187 nkat/g dry weight, K(M) = 1.38 mM) with D-phenylalanine as substrate were calculated in 40% [BMIM][BF(4)]. Bioconversions of D/L-phenylalanine in 40% [BMIM][BF(4)] and 20% [MMIM][MMPO(4)] on a 3 ml scale using immobilized DAAO were performed by addition of free catalase from Micrococcus lysodeikticus. After total conversion of substrate in presence of 20% [MMIM][MMPO(4)] the residual activity of the immobilized DAAO was 79% and 100% of the free catalase.

Biotransformation↗
PubMed2006

Branching patterns and drainage territories of the middle hepatic vein in computer-simulated right living-donor hepatectomies.

Full right hepatic grafts are most frequently used for adult-to-adult living donor liver transplantation (LDLT). One of the major problems is venous drainage of segments 5 and 8. Thus, this study was designed to provide information on venous drainage of right liver lobes for operation-planning. Fifty-six CT data sets from routine clinical imaging were evaluated retrospectively using a liver operation-planning system. We defined and analyzed venous drainage segments and the impact of anatomic variations of the middle hepatic vein (MHV) on venous outflow from segments 5 and 8. MHV variations led to significant shifts of segment 5 drainage between the middle and right hepatic vein. In cases with the most frequent MHV branching pattern (n = 33), a virtual hepatectomy closely right to the MHV intersected drainage vessels that provided drainage for 30% of the potential graft, not taking into account potential veno-venous shunts. In individuals with inferior MHV branches that extend far into segments 5 and 6 (n = 10), the overall graft volume at risk of impaired venous drainage increased by 5% (p < 0.001). If this is confirmed in clinical trials and correlated with intraoperative findings, the use of liver operation-planning systems would be beneficial to improve overall outcome after right lobe LDLT.

Computer Simulation↗
PubMed2006

A 19-year-old male with generalized seizures, unconsciousness and a deviation of gaze.

Light chain deposition disease (LCDD) is a form of monoclonal immunoglobulin deposition diseases (MIDD) which in contrast to light-chain derived (AL) amyloidosis is characterized by non-congophilic, non-fibrillary monoclonal protein deposits. Systemic organ deposits are common with the kidney being a major target organ. A clonal lymphoplasmocytic proliferation, e.g. plasmacytoma, is present in the majority of cases. Here we report on a 19-year-old male who presented with generalized seizures and an enhancing white matter lesion on MRI scans. A stereotactic brain biopsy revealed a low-grade B cell lymphoma with plasmacellular differentiation as well as lambda light chain deposits without birefringence under polarized microscopy. No systemic lymphoma manifestations or systemic light chain deposits were found, nor was a monoclonal gammopathy detectable in serum and urine. After systemic chemotherapy with three courses high-dose methotrexate the size of the lesion and the condition of the patient have remained stable for 24 months now. This is the first description of cerebral LCDD developing without systemic disease in conjunction with the diagnosis of a cerebral low-grade B cell lymphoma. We present the clinical, laboratory and radiological findings and discuss the pathogenesis of this unusual LCDD manifestation.

Adult↗
PubMed2005

Pharmacokinetics and efficacy of ifosfamide or trofosfamide in patients with intraocular lymphoma.

BACKGROUND: The prognosis of intraocular lymphoma (IOL) is poor, and the optimal treatment has not yet been defined. The study assesses ifosfamide (IFO) and trofosfamide (TRO) for treating IOL. PATIENTS AND METHODS: We prospectively evaluated the efficacy and aqueous penetration of intravenous IFO, oral TRO and their active 4-hydroxy (4-OH) metabolites in 10 patients with IOL. Doses varied from 1500 to 2000 mg/m2/day on days 1-3 for IFO and from 150 to 400 mg/day (continuous or intermittent administration) for TRO. Four patients had newly diagnosed disease, and six had relapsed after pretreatment. RESULTS: All patients responded to first treatment with IFO or TRO, and both of two patients responded to re-treatment with IFO on ocular relapse. Progression-free survival from the first treatment with IFO or TRO was > or = 6-18 months. In six of six patients, 4-OH metabolites were detected in the aqueous humor at a concentration of 0.32-1.56 microM immediately after IFO infusion with an aqueous/serum ratio of 0.19-0.54. 4-OH metabolites could be detected in one of three patients at a concentration of 7.2 microM 3-16 h after ingestion of TRO. CONCLUSIONS: IFO and TRO are active in IOL. IOL patients evidence aqueous penetration of 4-OH metabolites after intravenous administration of IFO.

Aged↗
PubMed2005

High-dose methotrexate toxicity in elderly patients with primary central nervous system lymphoma.

BACKGROUND: The dose of high-dose methotrexate (HDMTX) in elderly patients often has to be reduced, resulting in a loss of treatment efficacy. We evaluated HDMTX-related toxicity with special regard to age distribution in patients with primary central nervous system lymphoma (PCNSL) in a phase IV multicenter trial. PATIENTS AND METHODS: One hundred and fifty-four patients (median age 61 years; 89 patients >60 years old, 21 patients >70 years old) received 619 HDMTX cycles. Toxicity was evaluated prospectively using the WHO classification. Unless a reduced dose was required after calculating a decreased glomerular filtration rate (GFR), the patients received 4 g/m(2) HDMTX followed by leucovorin rescue. RESULTS: Toxicity was generally mild with toxicities of WHO grade > or =3 usually <10%. The differences in the incidence and severity of toxicity were not statistically significant between patients >60 years and < or =60 years old. The same was true for therapy termination owing to MTX toxicity and for delayed serum MTX clearance. Dose reduction significantly differed between patients < or =60 years and those >60 years old (18% versus 44%; P = 0.001). CONCLUSIONS: HDMTX is a safe treatment for PCNSL patients regardless of age, with adherence to dose reduction determined by calculating the GFR before each treatment cycle.

Adult↗
PubMed2005

delta-(D -alpha-Aminoadipoyl)-cleaving amidase of Ochrobactrum anthropi.

Ochrobactrum anthropi cleaved the delta-(D-alpha-aminoadipoyl)-side chain from delta-(D-alpha-aminoadipoyl)-7-amino-4-methylcoumarin, a beta-lactamase-resistant cephalosporin C analogue. In whole cell conversions up to 1 nkat g(-1) dry cell wt were achieved. O. anthropi possesses also gamma-D-glutamyltranspeptidase activity, 8 nkat g(-1) dry cell wt, the likely cause of delta-(D-alpha-aminoadipoyl)-cleavage.

2-Aminoadipic Acid↗
PubMed2005

CD56dimCD16neg cells are responsible for natural cytotoxicity against tumor targets.

The activation of natural killer (NK) cells leads to degranulation and secretion of cytotoxic granula. During this process, the lytic granule membrane protein CD107a becomes detectable at the cell surface. Based on this phenomenon, we have analyzed by a novel flow cytometry-based assay, the number and phenotype of NK cells responding to tumor targets. Using human leukemia and lymphoma cell lines, we observed a close correlation between CD107a surface expression and target cell lysis, indicating that NK cell cytotoxicity can be assessed by this method. The number of degranulating NK cells was closely related to the ratio of effector and target cells and showed a maximum at a ratio of 1:1. Moreover, we were able to show that the population of CD56(dim)/CD16(neg) NK cells is primarily responsible for the cytotoxic activity against tumor targets whereas neither CD56(dim)/CD16(pos) nor CD56(bright) NK cells degranulated in response to the cell lines. Our results indicate that the CD107a assay represents a promising new method for the quantification and characterization of cells exhibiting natural cytotoxicity.

Antigens, CD↗
PubMed2005

[Invasive fungal infections in patients after liver transplantation].

Advances in surgical technique, immunosuppression, and medical management have greatly improved clinical results after liver transplantation (LTx). Fungal infections in LTx-patients still represent serious complications and are associated with a significant decrease in survival. The majority of fungal infections in LTx-patients are caused by Candida species, which is explained by the major abdominal surgery. Aspergillus infections are second common, whereas other fungal infections such as pneumocystosis, cryptococcosis, or zygomycosis represent rare events. The high mortality of invasive fungal infections in LTx-recipients is explained by the severity of the underlying medical condition and by difficulties in diagnosis and medical therapy. Currently available diagnostic tests do not allow a timely and reliable diagnosis of invasive fungal infections in LTx-patients. Amphotericin B has been the standard treatment for invasive candidiasis and aspergillosis for many years but the high frequency of side effects limits its application. Fluconazole is widely used due to better tolerability and fewer drug interactions. Disadvantages are the lack of activity against Aspergillus species and the selection of resistant Candida strains. Progress is to be expected from new antimycotic agents belonging to azoles (voriconazole) and echinocandins (caspofungin) as these are less toxic and have a broad range of antimycotic activity. Analysis of prognostic factors allows identifying LTx-patients at high risk for invasive fungal infection. Antimycotic prophylaxis or pre-emptive therapy may improve clinical outcome in this patient subgroup.

Antifungal Agents↗
PubMed2004

Phosphatidylinositol 3-kinase regulates Ca2+ signaling in pancreatic acinar cells through inhibition of sarco(endo)plasmic reticulum Ca2+-ATPase.

Calcium is a key mediator of hormone-induced enzyme secretion in pancreatic acinar cells. At the same time, abnormal Ca(2+) responses are associated with pancreatitis. We have recently shown that inhibition of phosphatidylinositol 3-kinase (PI3-kinase) by LY-294002 and wortmannin, as well as genetic deletion of PI3-kinase-gamma, regulates Ca(2+) responses and the Ca(2+)-sensitive trypsinogen activation in pancreatic acinar cells. The present study sought to determine the mechanisms of PI3-kinase involvement in Ca(2+) responses induced in these cells by CCK and carbachol. The PI3-kinase inhibitors inhibited both Ca(2+) influx and mobilization from intracellular stores induced by stimulation of acini with physiological and pathological concentrations of CCK, as well as with carbachol. PI3-kinase inhibition facilitated the decay of cytosolic free Ca(2+) concentration ([Ca(2+)](i)) oscillations observed in individual acinar cells. The PI3-kinase inhibitors decreased neither CCK-induced inositol 1,4,5-trisphosphate [Ins(1,4,5)P(3)] production nor Ins(1,4,5)P(3)-induced Ca(2+) mobilization, suggesting that the effect of PI3-kinase inhibition is not through Ins(1,4,5)P(3) or Ins(1,4,5)P(3) receptors. PI3-kinase inhibition did not affect Ca(2+) mobilization induced by thapsigargin, a specific inhibitor of sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA). Moreover, SERCA blockade with thapsigargin abolished the effects of pharmacological and genetic PI3-kinase inhibition on [Ca(2+)](i) signals, suggesting SERCA as a downstream target of PI3-kinase. Both pharmacological PI3-kinase inhibition and genetic deletion of PI3-kinase-gamma increased the amount of Ca(2+) in intracellular stores during CCK stimulation. Finally, addition of the PI3-kinase product phosphatidylinositol 3,4,5-trisphosphate to permeabilized acini significantly attenuated Ca(2+) reloading into the endoplasmic reticulum. The results indicate that PI3-kinase regulates Ca(2+) signaling in pancreatic acinar cells through its inhibitory effect on SERCA.

Animals↗
PubMed2004

Response of relapsed or refractory primary central nervous system lymphoma (PCNSL) to topotecan.

The authors treated 16 immunocompetent patients with refractory or relapsed primary CNS lymphoma with topotecan. Fifteen patients had been pretreated with up to three chemotherapy regimens, three of them additionally with whole brain irradiation (WBI), and one with WBI alone. Four complete remissions and two partial remissions were achieved. Progression-free survival was 20% at 6 months and 13% at 12 months.

Adrenal Cortex Hormones↗
PubMed2004

[Consensus-recommendations for sirolimus in liver transplantation].

Sirolimus is an m-TOR inhibitor without renal side effects and potentially protects against the development of malignancy. Due to a higher incidence of complications in two trials and an official warning in the drug information, the use of Sirolimus in liver transplantation is limited. The participants of this consensus meeting had to analyse and evaluate the literature with respect to the potential role of Sirolimus in liver transplantation. This consensus statement follows the scheme normally employed for the presentation of guidelines including the grading of evidence (1a-5) and the extent of recommendation (A-C). Moreover, the consensus included the experience of the authors with respect to the handling of Sirolimus after liver transplantation.

Drug Therapy, Combination↗
PubMed2004

Split liver transplantation: past, present and future.

The technique of liver splitting offers an effective way of increasing the donor pool and decreasing pediatric waiting list mortality. A donor liver is divided in such a way that the left lateral liver graft can be transplanted into a small child and the right extended liver graft into an adult. This innovative technique did not harm the adult recipient pool. Because of its technical complexity and the initial poor results after split liver transplantation (SLT) this procedure has slowly gained acceptance in the Transplantation Community after its first introduction in 1988 (4). Small children with end stage liver disease suffered the most from the extreme shortage of cadaveric donor organs due to the difficulty of finding size-matched donors. The successful surgical development of SLT and a better donor and recipient selection have led to a reduction of the pediatric pretransplant mortality to nearly zero and to results comparable with those after whole organ transplantation (WLT). By splitting a donor organ into two 'full' hemi-grafts and providing a small adult ( < 60 kg) or a big child ( > 30 kg) with the full left graft and a medium-sized adult (60-80 kg) with the full right graft, a small-for-size situation for adolescents or adults can be avoided and the total number of available grafts can be increased. It is the goal to provide each recipient with its customized graft in the near future. However, splitting for two adults requires high technical skills and profound knowledge of the anatomic variations and should be performed in centers with large transplantation experience.

Adolescent↗
PubMed2003

[Pathophysiology of pain and neural therapy].

Neural therapy according to Huneke uses the injection of local anesthetics for diagnosis and treatment. Depending on the situation, a stimulus (and/or the interruption of pathological stress) is given into the areas of the reflector segment or into the so-called "interference fields". This can trigger and maintain a disease or pain symptoms outside of every segmental order. Neural therapy targets autoregulatory mechanisms of the autonomic nervous system (especially the sympathetic nervous system). The theoretical principles for this include knowledge of neurophysiology and modern physics.

Anesthetics, Local↗
PubMed2003

Assessment of the clinical and virological protection provided by a commercial inactivated bovine viral diarrhoea virus genotype 1 vaccine against a BVDV genotype 2 challenge.

A new genotype of bovine viral diarrhoea virus (BVDV), designated BVDV-2, has emerged in the last decade and in recent years the prevalence of BVDV-2 strains has increased. A vaccination-challenge study was carried out to determine the cross-protective efficacy of a commercial inactivated vaccine containing a BVDV-1 strain. A group of five BVDV-free calves was vaccinated twice and a second group of five calves served as negative controls. Two months after the first vaccination, all the calves were challenged intranasally with BVDV-2 strain BVD890. The clinical signs of disease, the changes in haematological variables and the level of viraemia were significantly less in the vaccinated group.

Animals↗