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Biomedical subjects

W Eberhardt

Publications and source records attributed to W Eberhardt.

At least 73 records · Page 4Linked to original sources
PubMed1996

Molecular mechanisms of dexamethasone inhibition of nitric oxide synthase expression in interleukin 1 beta-stimulated mesangial cells: evidence for the involvement of transcriptional and posttranscriptional regulation.

Inducible nitric oxide synthase (iNOS; EC 1.14.13.39) is expressed in rat glomerular mesangial cells upon exposure to the inflammatory cytokine interleukin 1 beta (IL-1 beta). We have reported that nanomolar concentrations of dexamethasone suppress IL-1 beta-induced iNOS protein expression and production of nitrite, the stable end product of NO formation, without affecting IL-1 beta-triggered increase in iNOS mRNA levels. We now have studied the mechanisms by which dexamethasone suppresses IL-1 beta-stimulated iNOS expression in mesangial cells. Surprisingly, nuclear run-on transcription experiments demonstrate that dexamethasone markedly attenuates IL-1 beta-induced iNOS gene transcription. However, this is counteracted by a prolongation of the half-life of iNOS mRNA from 1 h to 2.5 h by dexamethasone. Moreover, dexamethasone drastically reduces the amount of iNOS protein by reduction of iNOS mRNA translation and increased degradation of iNOS protein. These results indicate that glucocorticoids act at multiple levels to regulate iNOS expression, thus providing important insights into the treatment of inflammatory diseases.

Animals↗
PubMed1996

Therapeutic strategies for the inhibition of inducible nitric oxide synthase--potential for a novel class of anti-inflammatory agents.

In recent years, NO, a gas previously considered a potentially toxic chemical, has become established as a diffusible universal messenger mediating cell-cell communication throughout the body. In mammals, NO is a recognized mediator of blood vessel relaxation that helps to maintain blood pressure. In the central nervous system NO acts as a non-conventional neurotransmitter and participates in the establishment of long-term plasticity required for memory formation. In addition, NO is responsible for some parts of the host response to sepsis and inflammation and contributes to certain disease states. A number of strategies have emerged with regard to a pharmacological control of pathological NO overproductions. This review will discuss these novel therapeutic approaches that may provide new means for clinical medicine.

Animals↗
PubMed1996

Phase I study with a weekly 1 h infusion of paclitaxel in heavily pretreated patients with metastatic breast and ovarian cancer.

Paclitaxel has proven to be an active agent in the treatment of breast and ovarian cancer [Seidman AD, Ann Oncol 1994, 5 (Suppl. 6), 17-22], but the optimal dose and schedule remain undefined. We performed a phase I study with a weekly 1 h infusion of paclitaxel. After premedication, patients received a 1 h infusion of paclitaxel on days 1, 8, 15, 22, 29 and 36 (every 50 days) using the following dose levels: dose level 1 70 mg/m2, dose level 2 80 mg/m2, dose level 90 mg/m2, dose level 4 100 mg/m2, 20 patients (17 breast, 3 ovarian cancer) with anthracycline- or platinum-refractory disease entered this trial. No dose limiting toxicities occurred at dose levels 1-3. 2 of the 4 patients at dose level 4 had neutropenia WHO grade 4. At all dose levels responses could be observed. Maximal tolerable dose (MTD) was reached using dose level 4. Paclitaxel, given in a weekly 1 h infusion, is safe and shows mild toxicity in heavily pretreated breast and ovarian cancer patients. We recommend dose level 3 for phase II studies.

Adult↗
PubMed1996

Phase I/II study with a weekly 24-hour infusion of 5-fluorouracil plus high-dose folinic acid (HD-FU/FA) in intensively pretreated patients with metastatic breast cancer.

BACKGROUND: In metastatic breast cancer patients who have had prior exposure to anthracyclines, single agents induce less than 15% and combination chemotherapy less than 20%-30% of objective responses. Therefore more active and tolerable salvage regimens are needed. PATIENTS AND METHODS: Forty-three patients with advanced breast cancer pretreated with 1-5 (median 2) different chemotherapy regimens were entered into this phase I/II trial. Treatment consisted of folinic acid (FA) (500 mg/m2, i.v., 2-hour infusion) followed by a 24-hour infusion of 5-fluorouracil (FU) which was escalated from 1.5 g/m2 (dose level (dl 1)), to 1.8 g/m2 (dl 2) to 2.1 g/m2 (dl 3). Therapy was given as outpatient treatment once weekly times 6 followed by a 2-week rest. RESULTS: HD-FU/FA was well tolerated. No dose-limiting toxicity occurred at dl 1 or 2. Only 3/32 (9%) patients had WHO grade 3/4 toxicities (gastrointestinal toxicities, hand-foot-syndrome) at dl 3. The response rate for all 32 of the patients treated at dl 3 was 41% (13/32). In the 24 patients with anthracycline-refractory disease, a response rate of 41% (10/24) was achieved. The median remission duration was 11 months and the median survival time 19 months. CONCLUSIONS: This schedule of FU/FA is a safe outpatient treatment with substantial activity in intensively pretreated breast cancer patients.

Adult↗
PubMed1995

Interleukin 1 beta-induced expression of nitric oxide synthase in rat renal mesangial cells is suppressed by cyclosporin A.

The expression of inducible nitric oxide synthase (iNOS) is triggered in rat renal mesangial cells by exposure to the inflammatory cytokine interleukin 1 beta (IL-1 beta). Here we report that cyclosporin A (CsA) a potent immunosuppressive drug, inhibits IL-1 beta dependent iNOS expression in renal mesangial cells. Addition of CsA dose dependently suppresses IL-1 beta-induced nitrite formation (IC50 = 0.9 microM). Western- and Northern blot analyses of mesangial cell extracts reveal that the inhibition of IL-1 beta-induced nitrite formation by CsA is due to decreased iNOS protein and iNOS mRNA steady state levels. Using nuclear run on experiments we show that the transcription rate of the IL-1 beta-induced iNOS gene is reduced. Furthermore, by electrophoretic mobility shift analysis we demonstrate reduced DNA-binding of the nuclear factor NF kappa B, an essential component of the IL-1 beta-dependent upregulation of iNOS gene transcription. The data presented in this report suggest that the cellular machinery involved in the IL-1 beta dependent transcriptional upregulation of the iNOS gene in mesangial cells is a target for the action of CsA.

Animals↗
PubMed1995

[Biogenic organochlorine compounds--occurrence, function and ecological relevance].

Organic chlorinated compounds are of increasing interest due to their almost ubiquitous occurrence in the biosphere, their toxic and cancerogenic activity, and their environmental relevance. Despite the relatively high level of knowledge on anthropogenic chlorine compounds, knowledge about biogenic chlorine compounds is comparatively poor. This is astonishing because the quantity of natural emissions of particular organic chlorinated compounds into the ecosphere exceeds that from industrial production considerably. An overview of the occurrence, biosynthesis, and ecological significance of biogenic chlorine-containing organics is given in this article. Results of recent investigations on this topic are discussed and the natural elimination processes of organic chlorinated compounds presented.

Bacteria↗
PubMed1995

Phase I/II study with paclitaxel in combination with weekly high-dose 5-fluorouracil/folinic acid in the treatment of metastatic breast cancer: an interim analysis.

Phase II study results demonstrating high efficacy and low toxicity for a weekly schedule of high-dose 5-fluorouracil/folinic acid (5-FU/FA) in intensively pretreated metastatic breast cancer patients prompted the addition of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) to this regimen in a phase I/II trial in outpatients: high-dose 5-FU (24-hour infusion)/FA (2-hour infusion preceding 5-FU) is given for 6 weeks (days 1, 8, 15, 22, 29, and 36), with paclitaxel (3-hour infusion) administered on days 1 and 22; 2 weeks' rest follows. Folinic acid 500 mg/m2 was administered throughout; the respective 5-FU doses for dose levels 1 through 3 were 1.5, 1.8, and 2.0 g/m2 with paclitaxel 135 mg/m2. Dose level 4 (500 mg/m2 FA, 2.0 g/m2 5-FU, and 175 mg/m2 paclitaxel) was chosen for phase II evaluation. To date, 46 patients with bidimensionally measurable disease (four each at dose levels 1, 2, and 3, and 34 at dose level 4) have been entered. The 12 patients treated at dose levels 1 through 3 were titrated to level 4 doses when phase II began; 35 patients are evaluable for response. The median age is 46 years, and the median number of metastatic sites is 2.5. Fourteen patients had received adjuvant chemotherapy, nine chemotherapy for metastasis, and 23 chemotherapy both adjuvantly and for metastasis. Of 31 anthracycline-treated patients, 27 had anthracycline-resistant disease. No dose-limiting toxicity appeared until dose level 4, when grade 3 or 4 leukopenia and diarrhea occurred in 15 and eight, respectively, of 108 cycles. Mild to moderate mucositis, hand-foot syndrome, myalgia, and nausea/vomiting occurred in 20% to 40% of cycles. One (3%) of the 35 patients had a complete response, 18 (51%) had partial responses, 14 (40%) had stable disease, and two (6%) had disease progression. Eleven (55%) of 20 evaluable patients with anthracycline-resistant disease responded (95% confidence interval, 34% to 76%). Median time to maximum response was 2 months, and the remission duration was 8+ months. Median survival time has not been reached. Paclitaxel and weekly high-dose 5-FU/FA was well tolerated and highly effective, even in patients with anthracycline-resistant metastatic breast cancer. The regimen can be administered safely to outpatients.

Adult↗