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Biomedical subjects

M R Green

Publications and source records attributed to M R Green.

At least 145 records · Page 8Linked to original sources
PubMed1995

Comparison of fragmentation modes for the structural determination of complex oligosaccharides ionized by matrix-assisted laser desorption/ionization mass spectrometry.

Fragment ions from underivatized N-linked oligosaccharides ionized by matrix-assisted laser desorption/ionization mass spectrometry were obtained by spontaneous fragmentation on a magnetic sector mass spectrometer, by post-source decay (PSD) on a reflectron time-of-flight (TOF) instrument and by collision-induced dissociation on a magnetic sector instrument fitted with an orthagonal-TOF analyser. Spontaneous fragmentation on the magnetic sector instrument produced ions mainly by glycosidic cleavage together with two abundant ions formed by cross-ring cleavage of the reducing-terminal residue. The PSD spectra were similar, the majority of ions being formed by glycosidic cleavage. Internal fragment ions were abundant. High-energy collision-induced dissociation spectra recorded with the orthagonal-TOF analyser, differed considerably from the other types of spectra, particularly in the appearance of major fragment ions produced by cross-ring cleavages of most of the constituent monosaccharide residues. These ions allowed much sequence and branching information to be obtained from the oligosaccharide.

Carbohydrate Sequence↗
PubMed1995

Multimodality therapy in unresected stage III non-small cell lung cancer: the American Cooperative Groups' Experience.

Since the mid-1980s, the American Cooperative Cancer Treatment Groups (Cancer and Leukemia Group B, Eastern Cooperative Oncology Group, North Central Cancer Treatment Group. Radiation Therapy Oncology Group, Southwest Oncology Group) have performed several multimodality trials exploring combinations of chemotherapy and radiation in patients with Stage III non-small cell lung cancer. The initial trials had a sequential design with induction chemotherapy followed by radiation. Later trials have emphasized concurrent chemoradiation with or without induction chemotherapy. These trials have begun to have an impact on what is considered 'standard' therapy for patients with Stage III non-small cell lung cancer (NSCLC).

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Etoposide (VP-16) and cisplatin at maximum tolerated dose in non-small cell lung carcinoma: a Cancer and Leukemia Group B study.

A multi-institutional cooperative group trial was undertaken by the Cancer and Leukemia Group B (CALGB) to evaluate the efficacy of the combination of cisplatin and intravenous etoposide for the treatment of metastatic or recurrent non-small cell lung cancer (NSCLC). The doses used were those previously determined to be the maximally tolerated dose of this drug combination. Forty patients were entered into the trial, 37 of whom were eligible for evaluation. Cisplatin (35 mg/M2/day for 3 days) and etoposide (200 mg/M2/day for 3 days) were administered every 28 days for a planned 6 cycles of therapy. Sixteen of 37 evaluable patients (43%) responded to therapy. Myelosuppression was the dominant toxicity, with 89% of the patients experiencing grade 4 neutropenia, and nearly half grade 3 or 4 thrombocytopenia. Median survival was 8.5 months, with 30% of the patients alive at 1 year and 10% alive at 2 years. Malaise, fatigue, and peripheral neuropathy were the other major toxicities. The combination of etoposide at the dose of 200 mg/M2/day for 3 days and cisplatin at 35 mg/M2/day for 3 days is a highly potent combination against metastatic non-small cell carcinoma.

Adult↗
PubMed1995

Results of cancer and leukemia group B protocol 8935. A multiinstitutional phase II trimodality trial for stage IIIA (N2) non-small-cell lung cancer. Cancer and Leukemia Group B Thoracic Surgery Group.

From October 1989 to February 1992, 74 patients with mediastinoscopically staged IIIA (N2) non-small-cell lung cancer from 30 CALGB-affiliated hospitals received two cycles of preresectional cisplatin and vinblastine chemotherapy. Patients with responsive or stable disease underwent standardized surgical resection and radical lymphadenectomy. Patients who underwent resection received sequential adjuvant therapy with two cycles of cisplatin and vinblastine, followed by thoracic irradiation (54 Gy after complete resection and 59.4 Gy after incomplete resection or no resection at 1.8 Gy per fraction). There were no radiographic complete responses to the neoadjuvant chemotherapy, although 65 (88%) patients had either a response or no disease progression. During induction chemotherapy, disease progressed in seven patients (9%). Sixty-three patients (86%) had exploratory thoracotomy, and 46 of those (75%) had resectable lesions. A complete surgical resection was accomplished in 23 patients, and 23 patients had an incomplete resection with either a diseased margin or diseased highest node resected. Operative mortality was 3.2% (2/63). In 10 patients (22% of the 46 having resection) the disease was pathologically downstaged. There was no correlation between radiographic response to the induction chemotherapy and downstaging at surgical resection. The full protocol was completed by 33 patients (45% of original cohort). Overall survival at 3 years was 23%. Patients undergoing resection had significantly improved survival at 3 years compared with patients not having resection: 46% for complete resection (median 20.9 months), 25% for incomplete resection (median 17.8 months), and 0% for no resection (median 8.5 months). Five deaths occurred during the treatment period. A total of 18 of the 46 (39%) patients who underwent resection are either alive and disease-free or have died without recurrence.

Aged↗
PubMed1995

Delineating minimal protein domains and promoter elements for transcriptional activation by lentivirus Tat proteins.

Lentivirus Tat proteins comprise a novel class of RNA-binding transcriptional activators that are essential for viral replication. In this study, we performed a series of protein fusion experiments to delineate the minimal protein domains and promoter elements required for Tat action. We show that a 15-amino-acid region of equine infectious anemia virus (EIAV) Tat protein, when fused to the GAL4 or LexA DNA binding domain, can activate transcription in appropriate promoter contexts. In the natural human immunodeficiency virus type 1 long terminal repeat, activation by Tat is dependent on multiple binding sites for the cellular transcription factor SP1. We delineate a 114-amino-acid region of the SP1 glutamine-rich activation domain that when fused to the GAL4 DNA binding domain can support transcription activation by Tat. Using these Tat and SP1 derivatives, we show that Tat activation can be reconstructed on a completely synthetic promoter lacking all cis-acting elements unique to the human immunodeficiency virus long terminal repeat. Our results indicate that lentivirus Tat proteins have essential properties of typical cellular transcriptional activators and define useful reagents for studying the detailed mechanism of Tat action.

Animals↗
PubMed1995

Spot urine pancreolauryl test for use in infancy.

As a simple non-invasive test of possible pancreatic insufficiency 10 healthy infants, 13 infants with cystic fibrosis, and nine infants with unexplained diarrhoea and failure to thrive were given an emulsion containing fluorescein dilaurate and mannitol by mouth. A spot urine specimen was collected and results expressed as urinary fluorescein to mannitol ratios. Sensitivity of the test was 96% and specificity was 95%.

Cystic Fibrosis↗
PubMed1995

Schedule dependency of 21-day oral versus 3-day intravenous etoposide in combination with intravenous cisplatin in extensive-stage small-cell lung cancer: a randomized phase III study of the Cancer and Leukemia Group B.

PURPOSE: This was a randomized phase III study to test the schedule dependency of etoposide given as a conventional 3-day intravenous (IV) regimen versus a prolonged 21-day oral regimen for extensive-stage small-cell lung cancer (SCLC). Both regimens contained IV cisplatin. The objectives were to compare survival (primary end point) and to establish response rates, failure-free survival, and toxicity (secondary end points). PATIENTS AND METHODS: Patients with untreated measurable or assessable disease and normal organ function were eligible. Randomization was stratified according to performance status 0 versus 1 or 2. Treatment consisted of etoposide 130 mg/m2/d IV for 3 days and cisplatin 25 mg/m2/d IV for 3 days every 21 days for eight courses (schedule 1) versus etoposide 50 mg/m2/d orally for 21 days and cisplatin 33 mg/m2/d IV for 3 days every 28 days for six courses (schedule 2). In 1990, bioavailability of oral etoposide was assumed to be 50%, and the study was designed to deliver the same total doses of etoposide and cisplatin on both regimens over 24 weeks without the use of growth factors. RESULTS: Between December 1990 and October 1993, 306 eligible patients were entered. Of these, 69% were male and 66% were > or = 60 years of age; 21% had a performance status of 0, 47% a performance status of 1, and 32% a performance status of 2; 156 were randomized to receive schedule 1 and 150 to receive schedule 2. Overall median survival estimates were 9.5 and 9.9 months (difference not significant) for schedule 1 and schedule 2, respectively. The 95% confidence interval (CI) for overall survival, 8 to 11 months, was the same for both schedules, with 126 and 117 deaths on schedule 1 and 2, respectively. Both schedules also resulted in the same median failure-free survival estimate of 7 months (95% CI, 6 to 8 months on either schedule). Complete and partial responses were observed in 15% and 42% of patients on schedule 1 and 14% and 47% on schedule 2, respectively. The overall maximal hematologic toxicities grade 3 and 4 for leukocytes, neutrophils, platelets, and hemoglobin were, respectively, as follows: schedule 1, 62%, 85%, 32%, and 32%; schedule 2, 83%, 83%, 52%, and 53%. Lethal toxicity due to neutropenia and infection occurred in 4% of patients on schedule 1 and 10% on schedule 2 (difference not statistically significant). CONCLUSION: The two schedules of etoposide in combination with cisplatin did not result in differences in treatment outcome with respect to tumor response and survival. However, a significantly greater rate of severe or life-threatening hematologic toxicity was noted on the 21-day oral etoposide treatment schedule.

Administration, Oral↗
PubMed1995

Phase I study of paclitaxel and topotecan in patients with advanced tumors: a cancer and leukemia group B study.

PURPOSE: To define the dose-limiting toxicities (DLTs) and the recommended phase II doses of paclitaxel combined with topotecan, without and with filgrastim support. PATIENTS AND METHODS: Patients with advanced solid tumors and a maximum of one prior chemotherapy regimen for metastatic disease were eligible if they had a performance status of 0 to 1 and normal renal, hepatic, and bone marrow function. Prior treatment with taxanes or comptothecin analogs, and prior pelvic irradiation were not allowed. Patients with a history of cardiac disease or on medications known to affect cardiac conduction were excluded. The dose of topotecan was fixed at 1.0 mg/m2/d for 5 days. The dose of paclitaxel was escalated until the maximum-tolerated dose (MTD), without and with filgrastim 5 micrograms/kg subcutaneously (SC) on days 6 to 14, was reached. Paclitaxel was administered over 3 hours on day 1 before topotecan. Treatment cycles were repeated every 21 days. RESULTS: Of 46 patients entered, 45 were assessable for toxicity and 34 for response. The principal toxicity was neutropenia. Without filgrastim, the MTD of paclitaxel was 80 mg/m2 on day 1 in combination with topotecan 1.0 mg/m2/d for 5 days. With filgrastim, the dose of paclitaxel was escalated to 230 mg/m2 in combination with the same dose of topotecan. At this dose level, one patient had hematologic DLT and a second patient developed neuromuscular DLT. Three patients had a partial response (PR): one with head and neck cancer, a second with non-small-cell lung cancer, and the third with colon cancer. CONCLUSION: We conclude that paclitaxel can be given at clinically relevant doses in combination with topotecan and filgrastim. The recommended dose for phase II studies is paclitaxel 230 mg/m2 on day 1 and topotecan 1.0 mg/m2/day for 5 days with filgrastim 5 micrograms/kg on days 6 to 14.

Adult↗
PubMed1995

Dissecting protein:protein interactions between transcription factors with an RNA aptamer.

Nucleic acid aptamers isolated from random sequence pools have generally proven useful at inhibiting the interactions of nucleic acid binding proteins with their cognate nucleic acids. In order to develop reagents that could also be used to study protein:protein interactions, we have used in vitro selection to search for RNA aptamers that could interact with the transactivating protein Tax from human T-cell leukemia virus. Tax does not normally bind to nucleic acids, but instead stimulates transcription by interacting with a variety of cellular transcription factors, including the cyclic AMP-response element binding protein (CREB), NF-kappa B, and the serum response factor (SRF). Starting from a pool of greater than 10(13) different RNAs with a core of 120 random sequence positions, RNAs were selected for their ability to be co-retained on nitrocellulose filters with Tax. After five cycles of selection and amplification, a single nucleic acid species remained. This aptamer was found to bind Tax with high affinity and specificity, and could disrupt complex formation between Tax and NF-kappa B, but not with SRF. The differential effects of our aptamer probe on protein:protein interactions suggest a model for how the transcription factor binding sites on the surface of the Tax protein are organized. This model is consistent with data from a variety of other studies.

Base Sequence↗
PubMed1995

Sequential recognition of the pre-mRNA branch point by U2AF65 and a novel spliceosome-associated 28-kDa protein.

Splicing of pre-mRNAs occurs via a lariat intermediate in which an intronic adenosine, embedded within a branch point sequence, forms a 2',5'-phosphodiester bond (RNA branch) with the 5' end of the intron. How the branch point is recognized and activated remains largely unknown. Using site-specific photochemical cross-linking, we have identified two proteins that specifically interact with the branch point during the splicing reaction. U2AF65, an essential splicing factor that binds to the adjacent polypyrimidine tract, crosslinks to the branch point at the earliest stage of spliceosome formation in an ATP-independent manner. A novel 28-kDa protein, which is a constituent of the mature spliceosome, contacts the branch point after the first catalytic step. Our results indicate that the branch point is sequentially recognized by distinct splicing factors in the course of the splicing reaction.

Base Sequence↗
PubMed1995

A phase I trial of paclitaxel and etoposide for metastatic or recurrent malignancies.

Etoposide and paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) each exhibit substantial activity against a variety of solid tumors. Etoposide promotes accumulation of cells in late S phase and in G2. Paclitaxel causes cell arrest in G2 and M. In this phase I trial, an empiric combination of a fixed dose of etoposide daily for 3 days followed by a 3-hour intravenous infusion of escalating doses of paclitaxel on day 4 is being tested. Cycles are repeated every 3 weeks. Dose level I, etoposide 100 mg/m2 intravenously days 1 to 3 and paclitaxel 80 mg/m2 intravenously day 4, was well tolerated. Dose level 2, with paclitaxel at 120 mg/m2, is near completion and appears tolerable as well. Further escalation of the paclitaxel dose is anticipated. Once the maximum tolerated dose of this combination is defined, growth factor will be added and further escalation of the paclitaxel dose will be attempted.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Immunohistochemical evaluation of E-cadherin and epidermal growth factor receptor in non-small cell lung cancer.

Enhanced expression of the epidermal growth factor receptor and loss of expression of the cell-cell adhesion molecule E-cadherin have each been implicated in the development and progression of a variety of human malignancies. There is some evidence for a correlation between the expression of these two genes and the possible influence of the E-cadherin gene product on the expression of epidermal growth factor receptor. We evaluated 33 matched primary and metastatic non-small cell lung cancer specimens using immunohistochemical staining. There was a statistically significant correlation between staining intensity for epidermal growth factor receptor and E-cadherin in the primary tumors (P = 0.017, by Spearman correlation test). No difference was noted between primary and metastatic disease for either gene product. Studies that include clinical data are needed to clarify the significance of these findings and to evaluate whether these markers will help predict prognosis in tumors.

Biomarkers, Tumor↗
PubMed1995

Immunolocalization of E-cadherin in human head and neck cancer.

Loss of expression of the cell-cell adhesion molecule E-cadherin has been shown to have a potential role in the dedifferentiation and progression of many human malignancies. We applied immunohistochemical staining for E-cadherin to eight formalin-fixed, paraffin-embedded primary and matched metastatic human head and neck carcinomas. In tumors that contained both well-differentiated and poorly differentiated components, staining was notably reduced in the poorly differentiated cells. Staining was nearly identical or only slightly reduced in metastases compared to primary tumors. As found in previous reports, E-cadherin expression may be involved in the dedifferentiation of these tumors.

Blotting, Western↗
PubMed1994

The RNA polymerase I transcription factor, upstream binding factor, interacts directly with the TATA box-binding protein.

The accurate transcription of human rRNA genes by RNA polymerase I requires two transcription factors, upstream binding factor (UBF) and promoter selectivity factor (SL1). Human SL1 (hSL1) is a multisubunit complex, one of whose components is TATA box-binding protein (TBP). hSL1 binds to the core region of the rRNA promoter, but does so inefficiently in the absence of human UBF (hUBF). hUBF interacts with the upstream control element of the rRNA promoter and facilitates binding of hSL1. The molecular basis by which hUBF increases binding of hSL1 remains to be elucidated. In this report, we use an immobilized protein binding assay to identify and purify a 95-kDa TBP-binding polypeptide. Microsequence analysis reveals that the 95-kDa TBP-binding protein is hUBF. We show that hUBF is stably associated with TBP and is present in large TBP-containing complexes. Our results indicate that the cooperative binding of hUBF and hSL1 on the rRNA promoter is mediated by direct interaction between hUBF and TBP. We also provide evidence that hUBF associates with TFIID, a TBP-containing RNA polymerase II transcription factor.

Amino Acid Sequence↗