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Biomedical subjects

M R Green

Publications and source records attributed to M R Green.

At least 19 recordsLinked to original sources
PubMed1992

Chemotherapy of advanced Hodgkin's disease with MOPP, ABVD, or MOPP alternating with ABVD.

BACKGROUND AND METHODS: MOPP (mechlorethamine, vincristine, procarbazine, and prednisone) has been the standard treatment for Hodgkin's disease for almost 20 years. In a randomized, multicenter trial, we compared three regimens of primary systemic therapy for newly diagnosed advanced Hodgkin's disease in Stages IIIA2, IIIB, and IVA or IVB: (1) MOPP alone given for 6 to 8 cycles, (2) MOPP alternating with ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) for 12 cycles, and (3) ABVD alone for 6 to 8 cycles. Patients in a first relapse after radiation therapy were eligible. No additional radiation therapy was given. Patients who did not have a complete response or who had a relapse with either MOPP alone or ABVD alone were switched to the opposite regimen. RESULTS: Of 361 eligible patients, 123 received MOPP, 123 received MOPP alternating with ABVD, and 115 received ABVD alone. The patients were stratified according to age, stage, previous radiation, histologic features, and performance status. The overall response rate was 93 percent, with complete responses in 77 percent: 67 percent in the MOPP group, 82 percent in the ABVD group, and 83 percent in the MOPP-ABVD group (P = 0.006 for the comparison of MOPP with the other two regimens, both of which contained doxorubicin). The rates of failure-free survival at five years were 50 percent for MOPP, 61 percent for ABVD, and 65 percent for MOPP-ABVD. Age, stage (III vs. IV), and regimen influenced failure-free survival significantly. Overall survival at five years was 66 percent for MOPP, 73 percent for ABVD, and 75 percent for MOPP-ABVD (P = 0.28 for the comparison of MOPP with the doxorubicin regimens). MOPP had more severe toxic effects on bone marrow than ABVD and was associated with greater reductions in the prescribed dose. CONCLUSIONS: In this trial, ABVD therapy for 6 to 8 months was as effective as 12 months of MOPP alternating with ABVD, and both were superior to MOPP alone in the treatment of advanced Hodgkin's disease. ABVD was less myelotoxic than MOPP or ABVD alternating with MOPP.

Adult↗
PubMed1992

Cloning and intracellular localization of the U2 small nuclear ribonucleoprotein auxiliary factor small subunit.

U2 small nuclear ribonucleoprotein auxiliary factor (U2AF), an essential mammalian splicing factor, is composed of two subunits: a 65-kDa protein (U2AF65), which binds the pre-mRNA polypyrimidine tract and is required for in vitro splicing, and an associated 35-kDa protein (U2AF35). Here we report the isolation of a cDNA encoding U2AF35. U2AF35 contains sequence motifs found in several mammalian pre-mRNA splicing factors. We show directly that U2AF65 and U2AF35 interact with each other and delineate the regions of both proteins that mediate this interaction. Using anti-peptide antibodies against U2AF35, we show that the protein has the intracellular distribution characteristic of U2AF65. Both U2AF65 and U2AF35 are concentrated in a small number of nuclear foci corresponding to coiled bodies, subnuclear organelles first identified by light microscopy in 1903.

Amino Acid Sequence↗
PubMed1992

Retinoblastoma gene product activates expression of the human TGF-beta 2 gene through transcription factor ATF-2.

The retinoblastoma susceptibility gene product (pRb) plays an important role in constraining cellular proliferation and in regulating the cell cycle. The pRb inhibits transcription of genes involved in growth control (reviewed in ref. 3) and can regulate transforming growth factor beta 1 (TGF-beta 1) gene expression. TGF-beta isoforms also down-regulate cellular proliferation. To determine whether pRb also regulates expression of other TGF-beta isoforms, we examined the effect of pRb on the expression of the human TGF-beta 2 gene. The human TGF-beta 2 promoter contains multiple elements including an ATF site, which is essential for basal promoter activity. Here we report that pRb activates transcription of the human TGF-beta 2 gene. The promoter element responsible for pRb-mediated transcriptional regulation is a binding site for ATF proteins, an extensive transcription factor family. We provide evidence that implicates ATF-2 in pRb-responsiveness. First, the ATF promoter element in the TGF-beta 2 gene is a high-affinity ATF-2-binding site. Second, a GAL4-ATF2 fusion protein can support pRb-mediated transcriptional activation of a promoter containing GAL4-binding sites. Third, ATF-2 in nuclear extracts can interact with pRb. Our results reveal a new mechanism by which pRb constrains cellular proliferation: by activating expression of the inhibitory growth factor, TGF-beta 2.

Activating Transcription Factor 2↗
PubMed1992

Cloning and domain structure of the mammalian splicing factor U2AF.

A complementary DNA clone encoding the large subunit of the essential mammalian pre-messenger RNA splicing component U2 snRNP auxiliary factor (U2AF65) has been isolated and expressed in vitro. It contains two functional domains: a sequence-specific RNA-binding region composed of three ribonucleoprotein-consensus sequence domains, and an arginine/serine-rich motif necessary for splicing but not for binding to pre-mRNA.

Amino Acid Sequence↗
PubMed1992

Predicting genitourinary toxicity in patients receiving cisplatin-based combination chemotherapy: a Cancer and Leukemia Group B study.

Assessment of renal function prior to cisplatin chemotherapy has long been based on measurement of creatinine clearance by 24-hour urine collection (CrCmeas). Estimated creatinine clearance (CrCest) as calculated from the patient's age, weight, and serum creatinine level has been suggested as an adequate surrogate for CrCmeas, as it provides advantages of improved convenience, decreased cost, and possibly increased accuracy. We studied 847 patients receiving cisplatin-based chemotherapy on Cancer and Leukemia Group B (CALGB) protocols to determine whether the CrCmeas, CrCest, or serum creatinine value or the age of the patient would predict the subsequent genitourinary (GU) toxicity. Both CrCmeas (P = 0.001) and CrCest (P = 0.02) were predictive of subsequent grade 2+ GU toxicity, with CrCmeas being a slightly better predictor. Patient age also influenced subsequent GU toxicity, with the risk increasing with age (P = 0.0008). When patients were classified by age group and by CrCmeas, distinct subgroups were identified, with differences in the risk for grade 2+ GU toxicity ranging from 14% to 32%. Using a logistic model to assess the probability of grade 2+ GU toxicity, we found that an age of greater than or equal to 60 years (P = 0.005), a CrCmeas value of less than 75 ml/min (P = 0.004), and the risk characteristics of the individual cisplatin trial were important, whereas CrCest was not. Furthermore, CrCest proved to be a poor predictor of a CrCmeas value of less than 75 ml/min, "misclassifying" nearly half of the patients to a "lower-risk" subgroup. In summary, both CrCmeas and the patient's age independently provided predictive information concerning cisplatin GU toxicity. Our data support the continued clinical usefulness of determining the CrCmeas value prior to the administration of cisplatin-based chemotherapy to most patients.

Adult↗
PubMed1992

Intravenous 6-thioguanine or cisplatin, fluorouracil and leucovorin for advanced non-small cell lung cancer: a randomized phase II study of the cancer and leukemia group B.

This randomized phase II study was designed to evaluate the activity of intravenous 6-thioguanine (6-TG) as a single agent and the combination of cisplatin and 5-fluorouracil (5-Fu) modulated by oral leucovorin (PFL) in patients with advanced non-small cell lung cancer (NSCLC). Eligible patients had measurable or evaluable stage III B or IV NSCLC, had no received prior chemotherapy and had a performance status of 0-2. Patients were randomized to treatment with intravenous 6-TG at 55 mg/m2 administered over 30 minutes for 5 consecutive days and repeated every 35 days, or PFL chemotherapy with cisplatin 100 mg/m2 on day 1, 5-FU 800 mg/m2/day as a continuous intravenous infusion over 5 days and oral leucovorin administered at 100 mg every 4 hours during the entire duration of the cisplatin and 5-FU infusions. PFL was repeated every three weeks. Ninety-five eligible patients were randomized, 46 to 6-TG and 49 to PFL. Response rates were 4% for 6-TG (95% confidence interval 0.5%-14.8%, 1 partial, and 1 complete response) and 29% (16.6%-43.3%) for PFL (all partial). The median time to treatment failure was 2 and 4 months, respectively, and the median survival times were 6 and 10 months, respectively. Toxicities with 6-TG were, generally, mild to moderate but severe or life-threatening granulocytopenia was observed in 21% of patients. With PFL, mucositis was dose-limiting, and 78% of patients had severe or life-threatening mucositis. This led to dose reduction of 5-FU and leucovorin during subsequent cycles or treatment termination in 82% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Intensive etoposide and carboplatin chemotherapy for advanced non-small-cell lung cancer. A phase II trial of the Cancer and Leukemia Group B.

From April 2 to July 9, 1989, Cancer and Leukemia Group B (CALGB) conducted a Phase II study of etoposide and carboplatin in advanced (AJC Stage IIIb-IV) non-small-cell lung cancer (NSCLC) patients whose performance status (PS) was 0-2. The combination was given at the maximum tolerated dose as defined in a prior CALGB study. Of 76 eligible patients with follow-up data, complete responses were achieved in three patients (4%) and partial responses, in five patients (7%). One patient (1%) with evaluable disease showed improvement. There was only one partial response in the PS 2 patients. Performance status was a predictive factor for response or improvement (p = 0.0368). A high incidence (74%) of severe or life-threatening hematologic toxicity and fatal sepsis in four patients was a reflection of the intensity of the chemotherapeutic regime. The median survival from study entry was 7.4 months. Thirty-seven percent of the patients survived beyond 1 year; the median survival for the PS 0-1 patients was 11.7 months for the PS 2 patients, 4.1 months. Median time to treatment failure was 3.9 months, but treatment had not failed in 9% of the patients after 1 year, all of whom were PS 0-1 at time of study entry. Although the response rate with this dose-intensive chemotherapy regimen was disappointing, the median survival of PS 0-1 patients was equivalent to that of Stage III NSCLC patients in prior CALGB studies. In patients with NSCLC who are treated with chemotherapy, PS may be as important a prognostic factor as stage, when median survival is used as an endpoint.

Adult↗
PubMed1992

Rat hair follicle growth in vitro.

Pelage hair follicles were isolated by gentle microdissection from 8-12-day-old rats, and maintained in supplemented Williams E medium. Length measurements made on freshly isolated hair follicles, and at 24-h intervals, showed a significant increase in hair follicle length over 48 h, after which time no further significant increase in length was observed. Photomicrographs of maintained follicles showed that this increase in hair follicle length could be attributed to the production of a keratinized hair shaft. Histology and [methyl-3H] thymidine autoradiography of freshly isolated hair follicles showed the dermal papilla to be elongated, with thymidine uptake located predominantly in the matrix cells of the hair follicle bulb adjacent to the dermal papilla. This pattern remained unaltered for the first 48 h of maintenance, but after 72 h the dermal papilla had rounded into a tight ball of cells, with very little thymidine uptake occurring in the adjacent matrix cells. On maintenance, fetal calf serum (FCS), epidermal growth factor (EGF) and 12-o-tetradecanoyl phorbol 13-acetate (TPA) all significantly stimulated [methyl-3H] thymidine and [U-14C] leucine uptake, but inhibited hair follicle elongation. Insulin-like growth factor-1 (IGF-1) had no significant effect on rates of hair follicle elongation and [methyl-3H] thymidine uptake, but significantly stimulated rates of [U-14C] leucine uptake. Transforming growth factor-beta 1 (TGF-beta 1) significantly inhibited both the rate of [methyl-3H] thymidine uptake and hair follicle elongation.

Animals↗
PubMed1992

Intensive combination chemotherapy, concurrent chest irradiation, and warfarin for the treatment of limited-disease small-cell lung cancer: a Cancer and Leukemia Group B pilot study.

PURPOSE: In prior Cancer and Leukemia Group B (CALGB) studies, combined chemotherapy and thoracic irradiation was superior to chemotherapy alone in limited-disease (LD) small-cell lung cancer (SCLC). A combined modality pilot study was performed to test the feasibility of adding warfarin to aggressive chemoradiotherapy for LD SCLC. PATIENTS AND METHODS: Combination chemotherapy with doxorubicin 45 mg/m2 intravenously (IV) on day 1, cyclophosphamide 800 mg/m2 IV on day 1, and etoposide (ACE) 80 mg/m2 on days 1 to 3 was given every 21 days for the first three courses. The fourth and fifth courses substituted cisplatin 33 mg/m2 IV on days 1 to 3 for the doxorubicin, with concurrent chest irradiation to a total of 4,000 cGy given in 20 fractions during a 4-week period followed by a boost of 1,000 cGy in five fractions during a 1-week period. Prophylactic cranial irradiation, 3,000 cGy was given concurrently in 10 fractions during a 2-week period. Courses 6 to 8 again used ACE chemotherapy, but courses 4 to 8 were given on a 28-day schedule with dose adjustment for hematologic or renal toxicity. Warfarin was given throughout the treatment period titrated to achieve a prothrombin time (PT) of 1.5 to 2 times the control. Patients with histologically proven limited-stage SCLC, good performance status, and normal renal, hematologic, and hepatic functions were eligible. RESULTS: Sixty-one of 66 patients entered onto the study were eligible and assessable. Fifty-four (89%) (95%) confidence interval [CI], 78% to 95%) experienced an objective response, 35 (57%) achieved a complete response (CR) (95% CI, 44% to 70%), and 17 (28%) achieved a partial response (95% CI, 16% to 39%). Median durations were CR, 26.3 months; failure-free survival, 11.8 months; and survival, 18 months. Forty-one percent of the patients were alive at 2 years, 33% were alive at 3 years, and 25% were alive at 4 or more years. Median follow-up for survivors is 5 years (range, 3.5 to 5.9 years). Severe or life-threatening myelosuppression occurred in 90%, infection occurred in 34%, fever without documented infection occurred in 26%, and pulmonary toxicity occurred in 6%. Another 6% of patients experienced severe or life-threatening hemorrhages. There were four treatment-related fatalities. The pulmonary toxicities have been associated with the resumption of ACE chemotherapy after chest irradiation. CONCLUSIONS: These highly encouraging response and survival results compare favorably with any prior CALGB group study. Although they are somewhat more toxic, they are comparable to the best published results. A randomized study that examines the role of warfarin is underway.

Adult↗
PubMed1992

Neoadjuvant chemotherapy and radiotherapy followed by surgery in stage IIIA non-small-cell carcinoma of the lung: report of a Cancer and Leukemia Group B phase II study.

PURPOSE: This phase II trial was designed to evaluate the feasibility, toxicity, response rates, and survival for neoadjuvant chemotherapy and radiotherapy (RT) followed by surgical resection in newly diagnosed patients with surgically staged IIIA non-small-cell lung carcinoma (NSCLC). PATIENTS AND METHODS: Previously untreated patients with NSCLC underwent bronchoscopy, chest and abdominal computed tomography (CT), bone scan, and surgical staging of the mediastinum. Neoadjuvant treatment consisted of concurrent chemotherapy and RT. Patients then underwent surgical resection, which was followed in turn by additional chemotherapy and RT. Chemotherapy included cisplatin 100 mg/m2 on days 1 and 29, vinblastine 3 mg/m2 on days 1 and 3 and 29 and 31, and fluorouracil (5-FU) 30 mg/kg/d by infusion on days 1 to 3 and 29 to 31 (FVP). RT began on day 1 and included 3,000 cGy in 15 fractions. Surgery took place on day 55, and one more cycle of chemotherapy and an additional 3,000 cGy of RT began on day 85. RESULTS: Forty-one eligible patients (median follow-up, 53 months) were studied. N2 disease was present in 80%, whereas 20% had T3N0 or T3N1 lesions. Response to neoadjuvant chemotherapy and RT included no complete responses (CR), 21 (51%) partial responses (PR) or regressions, 19 (46%) stable disease (SD), and one (2%) progressive disease (PD). Thirty-one patients underwent surgery, and 25 were resected. In four of the 25 resection specimens, no viable tumor was present, whereas in three of the six unresectable patients, extensive biopsy results demonstrated only necrotic tumor. The maximum response achieved using all protocol treatment was 27 (66%) CRs, seven (17%) PRs or regression, six (15%) SDs, and one (2%) PD. Toxicity was substantial and primarily hematologic. There were six (15%) treatment-related deaths, which included three perioperative deaths and three chemotherapy-related toxicity deaths. The Kaplan-Meier curve indicated a 1-year survival of 58% and a median survival of 15.5 months. Nine patients (22%) remain disease-free. CONCLUSIONS: There was a reasonably high rate of PR associated with concurrent neoadjuvant chemotherapy and RT, and a high percentage of patients who ultimately were rendered completely disease-free. However, treatment-related morbidity and mortality was common. Median survival seemed to be only modestly improved beyond that achieved with less intensive means of treatment. However, a group has emerged of patients who enjoy prolonged disease-free survival and possible cure.

Adult↗
PubMed1992

Phase II trial of high-dose 24-hour continuous intravenous 5-fluorouracil for advanced non-small cell lung cancer: a Cancer and Leukemia Group B study.

Eighty-six eligible patients with non-small cell lung cancer were treated on a Phase II, CALGB study with high-dose, 24-h continuous intravenous 5-fluorouracil every 2 weeks. Objective responses were seen in 7 (8%) patients with 1 (1%) complete response and 6 (7%) partial responses. The median survival for these patients without prior chemotherapy was 3.8 months. Gastrointestinal and hematologic toxicity were acceptable for most patients. However, two patients experienced acute clinical deterioration characterized by worsening central nervous system and hemodynamic function beginning near the completion of chemotherapy treatment and resulting in death. Because of its potential for severe, unpredictable neurologic and cardiac toxicity, we do not recommend this dose and schedule of 5-FU for future trials.

Carcinoma, Non-Small-Cell Lung↗
PubMed1992

Carboplatin in non-small cell lung cancer: an update on the Cancer and Leukemia Group B experience.

Since 1984, the Respiratory Committee of the Cancer and Leukemia Group B (CALGB) has evaluated carboplatin, either alone or in combination, in five separate phase II studies for patients with inoperable non-small cell lung cancer (NSCLC). All patients had an Eastern Cooperative Oncology Group performance status of 0 to 2 and had not received previous treatment with chemotherapy. In 70 patients with stage IIIB or IV disease, carboplatin 400 mg/m2 administered intravenously once every 4 weeks produced a 16% overall response rate and an acceptable toxicity profile. Subsequently, combinations of carboplatin/cisplatin, carboplatin/etoposide, and carboplatin/vinblastine have been evaluated in similar patient groups. Response rates of 11%, 12%, and 20%, respectively, were obtained. Myelosuppressive toxicity was substantially greater with carboplatin/etoposide and carboplatin/vinblastine than with carboplatin alone. Carboplatin/vinblastine demonstrated efficacy similar to that of the cisplatin/vinblastine combination previously evaluated by CALGB for treatment of similar patients with advanced NSCLC; ease of administration and lack of significant nephrotoxicity also compared favorably with cisplatin-based therapy. In regional NSCLC patients, carboplatin 100 mg/m2/wk can be administered intravenously concurrently with 60 Gy thoracic radiotherapy given over 6 weeks. The impact of concurrent carboplatin added to a sequential chemotherapy-radiotherapy program for patients with regional NSCLC is currently under study by the CALGB Respiratory Committee.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

A dose-escalation study of carboplatin/cyclophosphamide/etoposide along with autologous bone marrow or peripheral blood stem cell rescue.

Twenty patients have received 21 courses of high-dose cyclophosphamide (6 g/m2 over 4 days), etoposide (1,800 mg/m2 over 3 days), and carboplatin (800 to 1,600 mg/m2 by continuous infusion over 96 hours) and autologous bone marrow or peripheral blood stem cell rescue. The maximum tolerated dose of this regimen included these doses of cyclophosphamide and etoposide with a total of 1,600 mg/m2 carboplatin. Acute renal failure was the dose-limiting toxicity and, at the maximum tolerated dose, was observed in two patients of 14 evaluable courses. Nonhematologic toxicity was otherwise modest, and the overall response rate was 70% in patients with a wide variety of solid hematologic neoplasms.

Acute Kidney Injury↗
PubMed1991

A comparative study of two different doses of cytarabine for acute myeloid leukemia: a phase III trial of Cancer and Leukemia Group B.

Between 1982 and 1986, 326 evaluable patients with acute myeloid leukemia (AML) were randomized to receive cytarabine (Ara-C) at 200 mg/m2 (A200) or 100 mg/m2 (A100) for induction and maintenance therapy. Cycle 1 of induction therapy consisted of 7 days of continuous intravenous (IV) Ara-C and 3 days of i.v. daunorubicin (DNR); cycle 2, if needed, consisted of 5 days of Ara-C and 2 days of DNR. Complete responders (CR) then received monthly subcutaneous (SC) Ara-C at the respective doses (A100 or A200) with 6-thioquanine (6TG) at months 1 and 5, with vincristine (VCR) and prednisone at months 2, 4, 6, and 8, and with DNR at months 3 and 7. Complete response rates were 58% (A100) and 64% (A200) (P = .29). Median survival was 46 weeks (A100) and 38 weeks (A200) (P = .64); 5-year survival was 10% (A200) and 8% (A100). Median time to remission was 6.7 weeks (A200) and 8.1 weeks (A100) (P = .18). Median disease-free survival was 41 weeks (A200) and 44 weeks (A100) (P = .86). Deaths were attributed to therapy-related toxicities in 21% (A200) and 13% (A100) (P = .05). The 5-year survival was 15% for patients with performance status (PS) 0, 8% for PS 1 to 2, and 2% for PS 3 to 4, 18% for patients less than 40 years, 8% for ages 40 to 59, and 3% for age 60 or greater. Stratification of data by age and PS suggested that A200 may improve survival in patients less than 60 years with a good PS 0 (P = .05). This trial does not support the superiority of A200 over A100 in the treatment of AML.

Acute Disease↗
PubMed1991

HIV-1 Rev regulation involves recognition of non-Watson-Crick base pairs in viral RNA.

We have used an iterative in vitro genetic selection to identify the important structural features of the viral RNA element bound by the Rev protein of human immunodeficiency virus type 1 (HIV-1). Functional Rev-binding RNAs were selected from a pool of 10(13) variants of the wild-type Rev-binding domain. Bases conserved among the binding species define a 20 nucleotide core binding element. Covariation of some of these conserved bases indicates that the Rev-binding element is a stem-bulge-stem with a G:G base pair in the bulge. Mutational studies show that this non-Watson-Crick base pair is required for Rev binding in vitro and Rev responsiveness in vivo. We propose that the G:G base pair distorts the sugar-phosphate backbone of viral RNA and that this distortion is a critical determinant of recognition by Rev.

Base Sequence↗
PubMed1991

Binding of general transcription factor TFIIB to an acidic activating region.

A central issue in eukaryotic transcriptional regulation is the mechanism by which promoter-specific transcription factors (activators) stimulate transcription. Two lines of evidence indicate that the general transcription factor TFIIB is a pivotal component in the mechanism by which an acidic activator functions. First, during assembly of the preinitiation complex TFIIB binding is a rate-limiting step enhanced by an acidic activator. Second, the TFIIB activity in a HeLa cell nuclear extract is specifically retained on a column containing an acidic activating region. But because our previous study monitored only TFIIB activity, it remains possible that the interaction between TFIIB and the acidic activating region is mediated through additional proteins, for example, those designated as adaptors, coactivators or mediators. A complementary clone encoding TFIIB has recently been isolated and shown to encode a polypeptide of relative molecular mass 35,000. Here we report that TFIIB expressed in and purified from Escherichia coli (recombinant TFIIB) binds directly to the potent acidic activating region of the herpes simplex virus-1 VP16 protein.

Base Sequence↗
PubMed1991

Oligomerization and RNA binding domains of the type 1 human immunodeficiency virus Rev protein: a dual function for an arginine-rich binding motif.

The Rev protein of human immunodeficiency virus type 1 is a sequence-specific RNA binding protein that is essential for viral replication. Here we present evidence that Rev is a stable oligomer both in vitro and in vivo. Analysis of Rev mutants indicates that oligomerization is essential for RNA binding and hence Rev function. The oligomerization and RNA binding domains overlap over 47 amino acids. Within this region is a short arginine-rich motif found in a large class of RNA binding proteins. Substitution of multiple residues within the arginine-rich motif abolishes oligomerization, whereas several single-amino-acid substitution mutants oligomerize but do not bind RNA. Thus, Rev's arginine-rich motif participates in two distinct functions: oligomerization and RNA binding.

Amino Acid Sequence↗