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Biomedical subjects

M Weil

Publications and source records attributed to M Weil.

At least 37 records · Page 2Linked to original sources
PubMed1997

Is programmed cell death required for neural tube closure?

Programmed cell death (PCD) plays an important part in animal development. It is responsible for eliminating the cells between developing digits, for example, and is involved in hollowing out solid structures to create cavities (reviewed in [1] [2]). There are many cases, however, where PCD occurs in developing tissues but its function is unknown. Important examples are seen during the folding, pinching off, and fusion of epithelial sheets during vertebrate morphogenesis, as in the formation of the neural tube and lens vesicle [2]; PCD is an invariable accompaniment to these processes, but it is unclear whether it is required for the processes to occur or is just an unavoidable consequence of them. There is increasing evidence that PCD in animals is mediated by a family of cysteine proteases, known as caspases, which are thought to act in a proteolytic cascade, cleaving one another and key intracellular proteins to kill the cell in a controlled way [3] [4]. Inhibitors of caspases are, therefore, potential tools for studying the roles of PCD during animal development [5] [6]. Here, we show that peptide caspase inhibitors block neural tube closure in explanted chick embryos, suggesting that PCD is required for this crucial developmental process.

Animals↗
PubMed1997

Preliminary results of a phase I/II study of paclitaxel, cisplatin, and cyclophosphamide in advanced ovarian carcinoma.

The clinical activity and toxicity of the triple combination of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ), cyclophosphamide, and cisplatin was assessed in both previously treated and untreated women with advanced ovarian carcinoma. Paclitaxel 175 mg/m2 was administered over 3 hours following standard premedication (prednisolone, dexchlorpheniramine, and cimetidine). Cisplatin 80 mg/m2 and cyclophosphamide 600 mg/m2 were given 6 to 12 hours after paclitaxel. Treatment was given at 3-week intervals for six cycles. Twenty-seven patients entered the study; 23 were evaluable for toxicity and 17 for response. Paclitaxel appeared to add additional efficacy to the standard cisplatin/cyclophosphamide regimen. Both the overall and complete remission rates were very high (88% and 70%, respectively), and histologically confirmed complete remissions exceeded 60%. Longer follow-up is needed to determine the duration of these responses. The primary toxicities included leukoneutropenia, peripheral neuropathy, asthenia, and alopecia. Only two of 23 patients withdrew because of toxicity, however, and only two treatment cycles were complicated by neutropenic fever requiring intravenous antibiotics. No life-threatening toxicities were encountered, although the peripheral neuropathy was poorly and slowly reversible and may have a significant impact on the patients' quality of life.

Adult↗
PubMed1997

Salpêtrière Hospital experience with biochemotherapy in metastatic melanoma.

PURPOSE: This article investigates the safety and efficacy of a simple cisplatin-based biochemotherapy regimen, containing single-agent cisplatin plus recombinant interleukin-2 (rIL-2) and recombinant interferon-alpha (rIFN-alpha), in the treatment of metastatic melanoma. PATIENTS AND METHODS: Between December 1990 and April 1997, 129 patients were treated with cisplatin (100 mg/m2, day 0) plus continuous intravenous infusion rIL-2 (18 MIU/m2/day, days 3-6 and days 17-21) and subcutaneous rIFN-alpha (9 MIU three times per week) plus or minus tamoxifen (160 mg/day) on three different protocols. Tumor response, disease-free survival, and overall survival were evaluated for all evaluable patients (N = 127). RESULTS: The overall response rate was 49%, and 10% of patients achieved a complete response. Responses were observed at all sites of metastases. In one case, a patient with a large cutaneous inguinal mass experienced a dramatic regression of that lesion within 1 month. The median disease-free survival was 5 months, and median overall survival was 11 months. Patients who responded had a significant survival advantage over nonresponders, and patients who achieved a complete response had a significant survival advantage over patients with a partial response. Toxicities were manageable and reversible upon discontinuation of therapy. CONCLUSION: The response rates achieved with this simple biochemotherapy regimen are comparable to those for other cisplatin-based biochemotherapy regimens, which use more complex multiagent chemotherapy regimens. We found no added clinical benefit from the addition of tamoxifen to cisplatin.

Adolescent↗
PubMed1996

[Chemotherapy and immunotherapy of metastatic malignant melanomas].

Prognosis in metastatic malignant melanoma is poor because of chemo and radiotherapy resistance. However, some drugs, such as dacarbazine, cisplatinum or fotemustine, a new nitrosourea, have produced a response rate of more than 20%. Combining these drugs increases response rate to 30-40%. Immunotherapy by interferon-alpha 2 shows about 15-20% response rate but interleukin-2 would be more effective especially in combination with cisplatinum and interferon-alpha 2 with 50% response and long survival after cessation of treatment.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

The "critical volume tolerance method" for estimating the limits of dose escalation during three-dimensional conformal radiotherapy for prostate cancer.

PURPOSE: To describe the "Critical Volume Tolerance" (CVT) method for defining normal tissue tolerance during 3D-based dose escalation studies for prostate cancer. METHODS AND MATERIALS: The CVT method predicts the tolerance to radiation for "in series"-type functional units based on the assumption that tolerance depends on a critical threshold "low-volume high-dose region." The data used for describing this model were generated from 3D analysis of randomly selected patients with prostate cancer. Commonly used coplanar four-and six-field conformal (SFC) techniques were chosen as the comparison techniques. For purposes of comparison, rectal tolerance was assumed to be reached following whole pelvic irradiation using a four-field box technique to 50 Gy, followed by a conedown boost to 70 Gy using bilateral 9 x 9 cm 120 degree arcs as popularized by investigators from Stanford University (SUH). RESULTS: Based on the average dose volume histograms for the patients studied, the maximum safe increase in dose for the SFC technique compared to the SUH technique, would be 10% if 30% of the rectal volume was the critical dose limiting volume (CVT = 30%), 5% if the CVT = 10%, or greater than 20% if the CVT = 40%. Commonly used four-field conformal techniques would not be expected to allow significant escalation of the dose without increasing the risk of complications. CONCLUSIONS: The CVT method is relatively simple, and data generated based on it can be used to support normal tissue complication probability equations. The CVT method can be verified or modified as partial tolerance data become available. Based on the CVT model, sophisticated treatment techniques should allow a modest increase in the total dose of radiation delivered to the prostate without an increase in late complications.

Dose-Response Relationship, Radiation↗
PubMed1996

Sucrose protects cell wall invertase but not vacuolar invertase against proteinaceous inhibitors.

Vacuolar (VI) and cell wall invertases (CWI) of higher plants can be inactivated in vitro and, possibly, in vivo by proteinaceous inhibitors. The respective mechanisms have not yet been compared. Therefore, partially purified CWI from transformed tobacco cells and VI from tomato fruit were preincubated with invertase-inhibitor fractions isolated from the same tissues. Both inhibitors were able to inhibit both invertases. However, VI was fully inhibited within less than 1 min by both inhibitors, whereas inactivation of CWI was much slower. Furthermore, CWI, but not VI, was strongly protected against inhibition by sucrose. A polyclonal antiserum directed against the tobacco inhibitor (I(NT)) cross-reacted with a 19 kDa polypeptide in the partially purified tomato inhibitor (I(LE)) fraction. The results indicate that I(NT) and I(LE)have similar structural properties, whereas the mechanism of inactivation is clearly different for CWI and VI.

Agrobacterium tumefaciens↗
PubMed1996

Complete remission seven years after treatment for metastatic malignant melanoma.

BACKGROUND: In this study, the authors identified seven-year survivors after completion of the French multicenter Phase II trial of fotemustine for the treatment of metastatic malignant melanoma. METHODS: One hundred sixty-nine patients with metastatic malignant melanoma were included in this Phase II study. One hundred fifty-three patient records were evaluable with an overall response rate of 24.2%. RESULTS: Five of these patients are alive and in complete remission. One patient had a complete response after fotemustine administration and then relapsed. One patient had a partial response. Three patients had stable disease. These five patients underwent surgery for relapse or residual disease and subsequently achieved durable complete remission. CONCLUSIONS: Long term survival may be the outcome after surgical resection of residual metastatic melanoma after chemotherapy.

Antineoplastic Agents↗
PubMed1996

The clinical measurement of volumes using helical CT.

The object of this preliminary study is to evaluate the new techniques of measurement by helical CT which allow direct assessment of the volume of a lesion in clinical practice particularly by obtaining direct macroscopic anatomical correlation. Its primary application is anatomical, with measurement of the volumes of organs or anatomical structures, the clinical importance of which relates primarily to oncology. We present our initial results, including their applications and limits, before extending this study to a larger series so that it may be compared with other multicentre evaluations.

Feasibility Studies↗
PubMed1996

Direct gene transfer of a plasmid carrying the herpes simplex virus-thymidine kinase gene (HSV-TK) in transplanted murine melanoma: in vivo study.

The aim of the study was to use a virus-free system to transfer the Herpes Simplex Virus-thymidine kinase (HSV-TK) gene in mice bearing melanoma tumours. B16 F1 murine melanoma cells were injected subcutaneously. On days 11 and 14, an intratumoral injection of either naked plasmid containing the HSV-TK gene (pAG0) or pAG0-lipofectamine complexes was given. Ganciclovir (120 mg/kg/day) was given for 5 days starting on day 14. Tumour weight reduction (40-50%) was observed in treated animals versus different control groups. Moreover, histopathological analysis on tumours showed large areas of cavitary necrosis (85%) in treated groups compared to controls (10%). Using a simple and safe method, the results presented here demonstrated that virus-free mediated delivery of the HSV-TK gene is efficient in vivo in murine malignant melanoma.

Animals↗
PubMed1996

The use of a partial transmission shield to reduce the optic chiasm doses during radiation therapy treatment of brain tumors.

Historically, brain tumors have been treated with lateral opposed beams for 40-45 Gy followed by more conformal reduced fields. Advances in treatment planning computers have led to the implementation of conformal non-axial techniques, allowing for escalation of dose. In patients where total doses exceed 50 Gy, adjacent critical structures can be protected with a partially shielded transmission block over the optic nerves and chiasm. By eliminating the conedown portion of the treatment a more cost and time effective treatment is achieved. Partially shielded blocks can be designed by using cerrobend or multileaf collimation. They can be included in the treatment plan and verified by an irregular field calculation and/ or thermoluminescent dosimeters.

Brain Neoplasms↗
PubMed1996

Role of Ced-3/ICE-family proteases in staurosporine-induced programmed cell death.

In the accompanying paper by Weil et al. (1996) we show that staurosporine (STS), in the presence of cycloheximide (CHX) to inhibit protein synthesis, induces apoptotic cell death in a large variety of nucleated mammalian cell types, suggesting that all nucleated mammalian cells constitutively express all of the proteins required to undergo programmed cell death (PCD). The reliability of that conclusion depends on the evidence that STS-induced, and (STS + CHS)-induced, cell deaths are bona fide examples of PCD. There is rapidly accumulating evidence that some members of the Ced-3/Interleukin-1 beta converting enzyme (ICE) family of cysteine proteases are part of the basic machinery of PCD. Here we show that Z-Val-Ala-Asp-fluoromethylketone (zVAD-fmk), a cell-permeable, irreversible, tripeptide inhibitor of some of these proteases, suppresses STS-induced and (STS + CHX)-induced cell death in a wide variety of mammalian cell types, including anucleate cytoplasts, providing strong evidence that these are all bona fide examples of PCD. We show that the Ced-3/ICE family member CPP32 becomes activated in STS-induced PCD, and that Bcl-2 inhibits this activation. Most important, we show that, in some cells at least, one or more CPP32-family members, but not ICE itself, is required for STS-induced PCD. Finally, we show that zVAD-fmk suppresses PCD in the interdigital webs in developing mouse paws and blocks the removal of web tissue during digit development, suggesting that this inhibition will be a useful tool for investigating the roles of PCD in various developmental processes.

Alkaloids↗
PubMed1996

Constitutive expression of the machinery for programmed cell death.

In the presence of cycloheximide (CHX) to inhibit protein synthesis, a high concentration of staurosporine (STS) induces almost all cells in explant cultures of 8/8 types of newborn mouse organs and 3/3 types of adult mouse organs to die with the characteristic features of apoptosis. Eggs and blastomeres also die in this way when treated with STS and CHX, although they are less sensitive to this treatment than trophectoderm or inner cell mass cells whose sensitivity resembles that of other developing cells. Human red blood cells are exceptional in being completely resistant to treatment with STS and CHX. As (STS plus CHX)-induced cell deaths have been shown to display the characteristic features of programmed cell death (PCD), we conclude that all mammalian nucleated cells are capable of undergoing PCD and constitutively express all the proteins required to do so. It seems that the machinery for PCD is in place and ready to run, even though its activation often depends on new RNA and protein synthesis.

Alkaloids↗
PubMed1996

Safer Choices: a multicomponent school-based HIV/STD and pregnancy prevention program for adolescents.

Given the serious consequences of HIV infection, other STDs, and pregnancy among teens, professionals must develop and evaluate new approaches to reduce risks associated with adolescent sexual behavior. The Safer Choices intervention is a comprehensive, theoretically based program designed to reduce risk behaviors and increase protective behaviors to prevent HIV, other STDs, and pregnancy among high school adolescents. The program includes five components: a School Health Promotion Council involving administrators, school staff, students, parents, and community members; curriculum and staff development activities; school environment activities designed and implemented by a team of peer educators; parent education activities; and school-community linkage activities. The School Health Promotion Council is responsible for planning and overseeing program implementation. This article describes the theoretical framework, process for intervention development, and key intervention strategies used in Safer Choices.

Adolescent↗
PubMed1996

Radiotherapy for high grade clinically localized adenocarcinoma of the prostate.

PURPOSE: We defined the efficacy of radiotherapy for the treatment of high grade (Gleason scores 8 to 10) adenocarcinoma of the prostate. MATERIALS AND METHODS: A total of 50 patients underwent radiotherapy with curative intent for clinically localized prostate cancer with Gleason scores of 8 to 10 at 1 of 4 facilities affiliated with the University of California San Francisco. Patients were considered to have biochemical failure if they had a significant increase in prostate specific antigen (PSA) of 0.5 ng./ml. per year, an increase in PSA to greater than 1.0 ng./ml. or a positive biopsy. RESULTS: Among the 50 patients median PSA was 22.7 ng./ml. (range 1.3 to 93.4). Tumors were clinical stage T1 or T2 in 46% of the cases and stage T3 or T4 in 54%. The overall actuarial probability of freedom from biochemical failure at 4 years was 23%. In a multivariate analysis including all patients pretreatment PSA was the only predictor of PSA failure, with 64% free of progression if the pretreatment PSA was 10 ng./ml. or less compared to only 16% at 3 years if PSA was more than 10 ng./ml. (p = 0.01). In a multivariate analysis restricted to patients with PSA less than 20 ng./ml. 83% of those treated to more than 71 Gy. were free of progression compared to 0% for those treated to less than 71 Gy. (p = 0.03). In a multivariate analysis PSA 10 ng./ml. or less (related risk 11.4, p = 0.02), T stage 1 or 2 (relative risk 3.8, p = 0.05) and radiation dose more than 71 Gy. (relative risk 4.0, p = 0.06) were associated with a favorable outcome. CONCLUSIONS: At 4 years the freedom from PSA failure following radiotherapy for high grade prostate cancer was comparable to previously reported surgical series. The high failure rate among patients with PSA greater than 20 ng./ml. suggests that these patients should be considered for investigational approaches. The apparent improvement in freedom from progression with the use of higher doses provides reason for optimism.

Actuarial Analysis↗
PubMed1996

Phase I/II study of paclitaxel, cisplatin, and cyclophosphamide in advanced ovarian carcinoma: preliminary results.

In this phase I/II study, we assessed the impact of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in the treatment of advanced ovarian carcinoma combined with the standard regimen cisplatin/cyclophosphamide given as follows: paclitaxel 175 mg/m2 (over 3 hours perfusion with standard premedication), cisplatin 80 mg/m2 (6 to 12 hours after paclitaxel), and cyclophosphamide 400 mg/m2. From February 1994 to January 1996, 27 patients (median age, 55 years; age range, 35 to 74 years) were entered into the study. Eight patients had distant metastases and 19 had early locoregional disease (stage III, 18 patients; stage IC, one patient). Twenty-two patients had undergone prior surgery (simple biopsy, six patients; optimally debulked, nine patients; suboptimally debulked, seven patients). Twenty-one patients had received no prior chemotherapy and six were previously treated with at least one platinum-based regimen. A maximum of six courses of paclitaxel/cisplatin/cyclophosphamide were given every 21 days. Twenty-three patients were evaluable for toxicity: neutropenia (World Health Organization grade 3/4), 91% of patients; thrombopenia (World Health Organization grade 3/4), 13% of patients; two episodes of neutropenia with fever; and neurotoxicity grade 3, 17% of patients. Alopecia grade 3 was reported in all patients. No hypersensitivity reactions and no cardiac toxicity was observed. Among 17 patients evaluable for response (patients with stage IV disease or stage III suboptimally debulked), 12 (70%) clinical complete responses (CRs) and three (18%) partial responses were observed. Among the 12 patients with CRs, 10 underwent second-look laparotomy and seven of them (70%) achieved a pathologic CR. In the group of 11 chemotherapy-naive patients evaluable for response, eight (72%) achieved a CR and three (28%) achieved a partial response. This combination seems to be safe, with very acceptable toxicity, and also seems to be highly active in the treatment of patients with advanced ovarian carcinoma.

Adult↗