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Biomedical subjects

J M Bennett

Publications and source records attributed to J M Bennett.

At least 55 records · Page 3Linked to original sources
PubMed2000

Phase I study of fludarabine plus cyclophosphamide in patients with previously untreated low-grade lymphoma: results and and long-term follow-up--a report from the Eastern Cooperative Oncology Group.

PURPOSE: To determine the toxicity and recommended phase II doses of the combination of fludarabine plus cyclophosphamide in chemotherapy-naive patients with low-grade lymphoma. PATIENTS AND METHODS: Previously untreated patients with low-grade lymphoma were entered onto dosing cohorts of four patients each. The cyclophosphamide dose, given on day 1, was increased from 600 to 1, 000 mg/m(2). Fludarabine 20 mg/m(2) was administered on days 1 through 5. The first eight patients were treated every 21 days; later patients were treated every 28 days. Prophylactic antibiotics were required. RESULTS: Prolonged cytopenia and pulmonary toxicity each occurred in three of eight patients treated every 3 weeks. The 19 patients treated every 28 days, who were given granulocyte colony-stimulating factor as indicated, did not have undue nonhematologic toxicity. Dose-limiting toxicity was hematologic. At the recommended phase II/III dose (cyclophosphamide 1,000 mg/m(2)), grade 4 neutropenia was observed in 17% of all cycles and 31% of first cycles. Grade 3 or 4 thrombocytopenia was seen in only 1% of all cycles. The median number of cycles per patient was six (range, two to 11) for all patients enrolled. The response rate was 100% of 27 patients entered; 89% achieved a complete and 11% a partial response. Nineteen of 22 patients with bone marrow involvement had clearing of the marrow. Median duration of follow-up was more than 5 years; median overall and disease-free survival times have not been reached. Kaplan-Meier estimated 5-year overall survival and disease-free survival rates were 66% and 53%, respectively. CONCLUSION: The recommended dosing for this combination in patients with previously untreated low-grade lymphoma is cyclophosphamide 1, 000 mg/m(2) day 1 and fludarabine 20 mg/m(2) days 1 through 5. The regimen has a high level of activity, with prolonged complete remissions providing 5-year overall and disease-free survival rates as high as those reported for other therapeutic approaches in untreated patients.

Adult↗
PubMed2000

World Health Organization classification of the acute leukemias and myelodysplastic syndrome.

Under the auspices of the European Association of Hematopathologists and the Society for Hematopathology, 100 hematopathologists and clinicians have met together and in subcommittees over a 5-year period. The model used was that developed by the International Lymphoma Study Group, which used morphologic, immunologic, and genetic features. It resulted in the revised European-American Lymphoma classification. The newly proposed leukemia classification uses a similar format and eliminates purely morphologic subtypes that have no current clinical relevance. As with all consensus proposals, these classifications must withstand criticism and debate by potential users.

Acute Disease↗
PubMed1999

Mitoxantrone, etoposide, and cytarabine plus cyclosporine for patients with relapsed or refractory acute myeloid leukemia: an Eastern Cooperative Oncology Group pilot study.

BACKGROUND: One potential mechanism of drug resistance to chemotherapy is the overexpression of multidrug resistance (MDR) genes coding for P-glycoprotein (P-gp), which leads to reduced intracellular retention of chemotherapy. This study tested the efficacy and toxicity of mitoxantrone, etoposide, and intermediate dose cytarabine (MEC) with cyclosporine (CSP) as an MDR modulator in patients with recurrent and refractory acute myeloid leukemia, and also correlated P-gp expression in leukemia cells with response. METHODS: Thirty-eight eligible patients who were in first recurrence after < 6 months of complete remission (CR) (11 patients), refractory to initial induction therapy or to one attempt at reinduction after recurrence (18 patients), in second recurrence (4 patients), or in recurrence after either allogeneic or autologous bone marrow transplantation (5 patients) received either MEC alone (13 patients) or MEC-CSP (25 patients). CSP was given as a loading dose of 6 mg/kg for 2 hours intravenously (i.v.) starting 2 hours before the first dose of etoposide, followed by a continuous i.v. infusion of 18 mg/kg/day for 98 hours. RESULTS: Three of the 13 patients (23%) who received MEC achieved CR, as did 6 of the 25 patients (24%) who received MEC-CSP. The median remission duration for all patients who achieved CR was 149 days (range, 26-466 days), 91 days (range, 81-172 days) for the 3 patients who received MEC, and 189.5 days (range, 26-466 days) for the patients treated with MEC-CSP. The median survival for the patients treated with MEC and MEC-CSP was 104 and 72 days, respectively. CONCLUSIONS: No significant association was found between P-gp expression and response. No apparent benefit in the CR rate, remission duration, or survival was observed with the addition of CSP to MEC.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Advances in the therapy of the myelodysplastic syndromes.

The study of the proliferation and differentiation of the MDS clone at the molecular level, including the details of apoptosis, may hopefully lead to more effective differentiation-induction/antiapoptotic agents. The study of the cytokines at the cellular/molecular level may lead to more effective trails of combination therapy with differentiation-induction agents, chemotherapy, and/or early-acting cytokines. Further phenotypic characterization of the MDS clone may lead to negative selection of these cells or positive selection of normal stem cells as part of an autotransplant strategy, as is presently being done in chronic-phase chronic myeologenous leukemia. The use of agents such as the topoisomerase I inhibitors (e.g., topotecan), which have mechanisms of action disparate from agents already used in MDS, may increase the efficacy of chemotherapy for MDS. The further clinical refinements in reducing treatment-related mortality and the study of T cells at the molecular level may hopefully lead to improvement in the prevention and therapy of graft-versus-host disease, in turn increasing the upper age limit of allogeneic BMT for MDS and increasing the feasibility of matched unrelated allogeneic BMT. At present, we can tailor the approach to a MDS patient based on his or her IPSS risk stratification, degree of cytopenia, and age, as outlined in Figure 2. At present, we can tailor the approach to a MDS patient based on his or her IPSS risk stratification, degree of cytopenia, and age, as outlined in Figure 2.

Apoptosis↗
PubMed1999

A quantitative PCR method for the assay of HIV-1 provirus load in peripheral blood mononuclear cells.

The use of high activity antiretroviral therapies (HAART) to treat HIV-infected patients frequently results in the long-term suppression of plasma virus RNA loads below levels detectable by current assays. The measurement of provirus DNA load in peripheral blood mononuclear cells provides a means of continuing to monitor the efficacy of treatment and the decline in reservoirs of latent virus. A quantitative PCR assay was developed for HIV-1 provirus using a three-point internal calibrator system to give high reproducibility and accuracy at the low copy numbers of provirus seen in clinical samples. Provirus DNA copies are related to cell number in the samples using a fluorescent dye-binding assay for measurement of input DNA. The assay agreed closely with an end-point dilution PCR and gave accurate quantification of extracts from an HIV-1 infected continuous cell line containing known provirus copy numbers. The inclusion of a second primer set in the LTR region of the HIV-1 genome, optimised to non-clade-B virus strains improved the detection and quantification of samples from patients infected with genetically divergent virus strains. Application of the assay to clinical trial patients showed no relationship between changes in provirus DNA loads and plasma virus RNA and changes in provirus load over 24 weeks were small.

Anti-HIV Agents↗
PubMed1999

Stress, social relations, and old age mortality in Taiwan.

The research analyzed the relationships among stress, social relations, and mortality in a probability sample of 4,049 Taiwanese adults, aged 60 and over. The baseline survey was conducted in 1989 and the survival status of the respondents was ascertained during the subsequent 4 years. Death of a spouse or a child was found to increase the risk of dying directly and indirectly, whereas major financial difficulty during the past 5 years and current financial strain influenced mortality indirectly through their effects on self-rated health disability. In addition to their direct effect on mortality, martial status and work status lowered the probability of dying through decreased disability and subjective ill health. Finally, no buffering effects of social support were substantiated.

Adaptation, Psychological↗
PubMed1999

Do cognitive processes predict mental health in individuals with rheumatoid arthritis?

The purpose of the present study was to assess the hypothesis that intellectual functioning affects the mental health of individuals with rheumatoid arthritis. Structural equation modeling techniques were used to assess the relative contributions of age, education, intellectual functioning, self-efficacy, and pain to mental health. It was hypothesized that individuals with rheumatoid arthritis who had higher intellectual functioning and higher self-efficacy would report better mental health than those with lower intellectual functioning and self-efficacy. One hundred twenty-one adults aged 34 to 84 with rheumatoid arthritis completed a battery of cognitive tasks, and multiple measures of self-efficacy, pain, and mental health, twice in 1 month. The data provided a good fit to the hypothesized model. Intellectual functioning was directly related to mental health and, also, indirectly related to mental health through self-efficacy and pain. Older individuals who performed poorly on cognitive tasks reported less self-efficacy, more pain, and poorer mental health than those individuals who performed well on cognitive tasks.

Adult↗
PubMed1999

DNA image cytometry in MDS bone marrow smears.

The nuclear DNA content, defined as DNA index (DI) in blasts/promyelocytes (bla/pro), were determined on Feulgen-stained bone marrow smears from 39 patients with myelodysplastic syndromes (MDS) and eight control subjects by the use of image cytometry (ICM). The DI in patients was compared to that of corresponding normal cell types, and to cytogenetic data available in 32/39 patients. The mean DI in bla/pro of patients with MDS was significantly (P < 0.01) lower compared to corresponding cell types in control subjects. By ICM, a DNA aneuploidy in bla/pro was found in 67% of the MDS patients, and 59% expressed DNA hypodiploidy. By cytogenetics, an abnormal karyotype was found in 31%, and 6/9 MDS patients with a 'hypodiploid' abnormal karyotype showed DNA hypodiploidy. Of patients with a normal karyotype (69%), seven (32%) showed a normal, 12 (55%) a lower, and three (14%) a higher DI compared to controls. No difference between groups of MDS patients was found. DNA hypodiploidy is suggested to be a common feature in MDS without a relationship to cytogenetics.

Adult↗
PubMed1999

The design and synthesis of potent inhibitors of hepatitis C virus NS3-4A proteinase.

Hepatitis C virus (HCV) is the cause of the majority of transfusion-associated hepatitis and a significant proportion of community-acquired hepatitis worldwide. Infection by HCV frequently leads to persistent infections that result in a range of clinical conditions including an asymptomatic carrier state, severe chronic active hepatitis, cirrhosis and, in some cases, hepatocellular carcinoma. The HCV genome consists of a single-stranded, positive sense RNA containing an open reading frame of approximately 9060 nucleotides. This is translated into a single polyprotein of approximately 3020 amino acids (C-E1-E2-p7-NS2-NS3-NS4A-NS4B-NS5A-NS5B), which in turn is processed by a series of host and viral proteinases into at least 10 cleavage products. The N-terminal portion of the NS3 protein encodes a serine proteinase that is responsible for the cleavage at the NS3-4A, NS4A-4B, NS4B-5A and NS5A-5B junctions. The 54 amino acid NS4A protein is a cofactor that binds to the NS3 protein and enhances its proteolytic activity. This report describes the expression of a recombinant NS3-4A proteinase fusion protein in Escherichia coli and the in vitro characterization of the enzyme activity using synthetic peptide substrates. It then demonstrates how these results were employed to guide the design of potent inhibitors of this enzyme.

Amino Acid Sequence↗
PubMed1999

A mouse model to study the effects of hormone replacement therapy on normal mammary gland during menopause: enhanced proliferative response to estrogen in late postmenopausal mice.

Hormone replacement therapy (HRT) with estrogen alleviates menopausal symptoms and is effective in reducing osteoporosis and cardiovascular disease when taken in early postmenopause. Older, late postmenopausal women who never previously received HRT are also believed to benefit from estrogen treatment. On the other hand, increased lifetime exposure of the mammary gland to estrogen may increase the risk of breast cancer. The development of suitable experimental animal model systems can advance our understanding of the effects of estrogen and the timing of HRT on the postmenopausal breast. Toward this end, early and late postmenopausal states were induced in mice by short vs. long term ovariectomy (1 vs. 5 weeks), and the effects of 17beta-estradiol (E) on mammary gland morphology, cell proliferation, and progesterone receptor (PR) levels were investigated. We report that in late postmenopausal mice, E caused a pronounced enlargement of duct ends and 6.5- and 4-fold greater mitogenic responses in the duct end epithelium and adjacent stromal cells, respectively, compared with the response in early postmenopausal mice. Furthermore, after long term, daily treatment with E, steady state levels of proliferation remained 2-fold higher than those of similarly treated, early postmenopausal mice. E failed to increase mammary PR levels in late postmenopausal, but not in early postmenopausal mice. Stimulation of duct ends by E and lack of PR inducibility are characteristics of the immature pubertal mammary gland and indicate that the late postmenopausal mammary gland resembled the immature state. In contrast, minimal E-induced proliferation and increased PR inducibility, characteristics of the adult, sexually mature mammary gland, were retained in early postmenopausal mice. The lack of difference in the numbers of estrogen receptor-positive epithelial or stromal cells or in estrogen receptor cellular concentration after short vs. long term ovariectomy indicates that the observed greater efficacy of E is mediated at a step beyond receptor-ligand binding. This mouse model of experimentally induced early vs. late postmenopausal states should prove useful in better understanding alterations in hormone responsiveness and their implications for timing of HRT on the human breast.

Age Factors↗
PubMed1998

Chemotherapy compared with autologous or allogeneic bone marrow transplantation in the management of acute myeloid leukemia in first remission.

BACKGROUND: In young adults with acute myeloid leukemia, intensive chemotherapy during the initial remission improves the long-term outcome, but the role of bone marrow transplantation is uncertain. We compared high-dose cytarabine with autologous or allogeneic marrow transplantation during the first remission of acute myeloid leukemia. METHODS: Previously untreated adolescents and adults 16 to 55 years of age who had acute myeloid leukemia received standard induction chemotherapy. After complete remission had been achieved, idarubicin (two days) and cytarabine (five days) were administered. Patients with histocompatible siblings were offered allogeneic marrow transplantation, whereas the remaining patients were randomly assigned to receive a single course of high-dose cytarabine or transplantation of autologous marrow treated with perfosfamide (4-hydroperoxycyclophosphamide). Oral busulfan and intravenous cyclophosphamide were used as preparative regimens for both allogeneic and autologous marrow transplantation. The end points were survival from the time of complete remission and disease-free survival. RESULTS: In an intention-to-treat analysis, we found no significant differences in disease-free survival among patients receiving high-dose chemotherapy, those undergoing autologous bone marrow transplantation, and those undergoing allogeneic marrow transplantation. The median follow-up was four years. Survival after complete remission was somewhat better after chemotherapy than after autologous marrow transplantation (P=0.05). There was a marginal advantage in terms of overall survival with chemotherapy as compared with allogeneic marrow transplantation (P=0.04). CONCLUSIONS: A postinduction course of high-dose cytarabine can provide equivalent disease-free survival and somewhat better overall survival than autologous marrow transplantation in adults with acute myeloid leukemia.

Acute Disease↗
PubMed1998

Characterization of substrates for use in X-ray multilayer optics.

The optical performance of platinum-carbon multilayers deposited onto different substrates has been examined. Specular reflectivity and non-specular diffuse scattering were measured to study the replication of substrate roughness into the multilayer structure. Surface topography was measured before and after deposition using a scanning probe microscope and a mechanical profiler.

Journal Article↗
PubMed1998

Plasmablastic morphology--an independent prognostic factor with clinical and laboratory correlates: Eastern Cooperative Oncology Group (ECOG) myeloma trial E9486 report by the ECOG Myeloma Laboratory Group.

We studied the prognostic significance of plasmablastic (PB) multiple myeloma (MM) in Eastern Cooperative Oncology Group Phase III trial E9486. Two reviewers independently reviewed 453 cases. They agreed on 37 PB (8.2%) cases and 416 non-PB cases, achieving an 85% concordance (P < .0001). These PB cases had significantly lower hemoglobin and serum albumin levels, higher calcium and beta 2-microglobuin levels, and higher percentage BM plasma cells (PC) by immunofluorescence. They had higher bone marrow PC labeling indices, higher serum soluble interleukin-6 receptor (sIL-6R) levels, and a higher probability of ras mutations. Three treatment regimens were used: vincristine, bis-chloro-ethyl nitrosourea (BCNU) melphalan, cyclophosphamide, and prednisone (VBMCP) alone; VBMCP with added cyclophosphamide (HiCy); or recombinant interferon alpha 2 (rIFNalpha2). Although the numbers are low, patients with PB had a significantly lower response rate versus non-PB MM when treated with VBMCP (treated, 47.1% v nontreated, 66.5% [P = .015]). Patients with nonresponding PB had a significantly higher progression rate than non-PB cases (30.6% v 11.8% [P < .0001]), especially with VBMCP alone (35.3% v 15.8% [P = .002]), and with added HiCy (37.5% v 9.8% [P < .0001]), but not with added rIFNalpha2. Event-free and overall survival of PB MM was shorter (median years, 1.1 v 2.7 and 1.9 v 3.7, respectively [P < .0001 for both]). In multivariate analysis, PB classification was also highly prognostic. There is no survival difference between the patients who were classified as PB by both reviewers versus patients classified as PB by only one reviewer. We conclude that PB MM is a discrete entity associated with more aggressive disease and shortened survival. Tumor cell ras mutations and increased sIL-6R may contribute to a higher proliferation rate and reduced survival. There were significant improvements in response and progression with the addition of HiCy and rIFNalpha2 to VBMCP, but the numbers were small and improved survival could not be shown.

Adult↗
PubMed1998

Role of epidermal growth factor in the acquisition of ovarian steroid hormone responsiveness in the normal mouse mammary gland.

The purpose of the present studies was to investigate the role of epidermal growth factor (EGF) in the acquisition of estrogen (E) and progestin (P) responsiveness in the mouse mammary gland in vivo. Using the Elvax 40P implant technique to introduce bioactive molecules directly into the mammary gland to produce a localized effect, we have made the novel observation that EGF implanted into glands of pubertal mice followed by E treatment resulted in the precocious acquisition of E-inducible progesterone receptors (PR). In sexually mature mice, EGF implants alone were able to increase PR. A neutralizing antibody specific for EGF blocked E-dependent stimulation of end-bud development and PR induction. Furthermore, the antiestrogen ICI 182,780 blocked the EGF-induced stimulation end-buds and PR induction, indicating that these EGF effects are mediated via estrogen receptors (ER). Immunohistochemical analysis showed that the endogenous EGF content of mammary glands of mature mice was higher than pubertal mice, that E implants caused a localized increase in mammary gland EGF content in both pubertal and mature mice, and that in mature mice E caused an increase in stromal cell EGF content. We have previously shown that the acquisition of E-inducible PR can be modulated by mammary stroma, and the present results indicate that mammary stroma could modulate hormonal responsiveness through control of local growth factor concentration. Taken together, these results provide evidence that E-dependent responses of mouse mammary gland in vivo, such as end-bud proliferation and PR regulation, may be mediated by EGF through an ER-dependent mechanism.

Animals↗