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David E Morris

Publications and source records attributed to David E Morris.

27 records · Page 2Linked to original sources
PubMed2003

Multiple mixed-valence behavior in trans,trans-[(tpy)(Cl)2Os(III)(mu-1,3-N3)Os(III)(Cl)2(tpy)]+. An azido bridge from the reaction between trans-[Os(VI)(tpy)(Cl)2(N)]+ and NH3.

Reaction between the Os(VI)-nitrido complex, trans-[OsVI(tpy)(Cl)2(N)]PF6 (tpy = 2,2':6',2' '-terpyridine), and ammonia (NH3) under N2 in dry CH3CN gives the mu-1,3-azido bridged [OsII-N3-OsII]- dimer, trans,trans-NH4[(tpy)(Cl)2OsII(N3)OsII(Cl)2(tpy)]. It undergoes air oxidation to give the [OsIII-N3-OsIII]+ analogue, trans,trans-[(tpy)(Cl)2OsIII(N3)OsIII(Cl)2(tpy)]PF6 ([OsIII-N3-OsIII]PF6), which has been isolated and characterized. The structural formulation as a mu-1,3-N3 bridged complex has been established by infrared and 15N NMR measurements on the 15N-labeled forms, [OsIII-14N=15N=14N-OsIII]+, [OsIII-15N=14N=15N-OsIII]+, and [OsIII-15N=15N=15N-OsIII]+. Cyclic voltammetric measurements in 0.2 M Bu4NPF6/CH3CN reveal the existence of five chemically reversible waves from 1.40 to -0.12 V for couples ranging from OsV-OsIV/OsIV-OsIV to OsIII-OsII/OsII-OsII. DeltaE1/2 values for couples adjacent to the three mixed-valence forms are 0.19 V for OsIII-OsII, 0.52 V for OsIV-OsIII, and >0.71 V for OsV-OsIV. In CH3CN at 60 degrees C, [OsIII-N3-OsIII]+ undergoes a [2 + 3] cycloaddition with CH3CN at the mu-N3- bridge followed by a solvolysis to give trans-[OsIII(tpy)(Cl)2(5-MeCN4)] and trans-[OsIII(tpy)(Cl)2(NCCH3)]PF6.

Journal Article↗
PubMed2003

Chemotherapeutic management of stage IV non-small cell lung cancer.

Stage IV non-small cell lung cancer (NSCLC) denotes the presence of metastatic disease and is largely incurable using present-day therapies. Chemotherapy remains a therapeutic option in this patient population, and there are many pertinent issues surrounding its use in patients with stage IV NSCLC. Eleven questions were framed by the American College of Chest Physicians Lung Cancer Guidelines Committee, and these were addressed by a systematic search of the available literature. The issues addressed included the identification of prognostic factors in selecting patients for chemotherapy and a critical analysis of the survival benefit provided by chemotherapy. Given the development of several new chemotherapy agents over the past decade, the impact that these agents have made was addressed as well as the definition of a standard of care regarding chemotherapeutic regimens. Given the fact that chemotherapy does not represent a curative option, other issues addressed were the optimal duration of treatment as well as its impact on symptom relief and quality of life, the role of second-line therapy, and the outcomes expectations from both first-line and second-line chemotherapy. The question of what specialty delivered the chemotherapy also was addressed. Once the data were identified, a critical analysis was undertaken attempting to objectively portray the data in support of answers for each of the questions posed. We believe the data support the fact that properly selected patients benefit from chemotherapy with regard to survival and palliation in both first-line and second-line settings. It appears that in trials addressing the duration of first-line therapy, this survival and palliative benefit occurs early, and prolonged therapy is not indicated. Therapy in this setting is cost-effective, and there are several regimens that can be considered to be "standard-of-care" options. Physicians involved in the diagnosis of these patients should be aware of the potential benefits of chemotherapy, allowing them to give recommendations to patients that are based on data derived from clinical trials. In addition, this awareness will allow them to make referrals, when appropriate, to physicians who are trained in the administration of chemotherapy and the management of patients undergoing such therapy.

Antineoplastic Agents↗
PubMed2002

High-dose conformal radiotherapy for treatment of stage IIIA/IIIB non-small-cell lung cancer: technical issues and results of a phase I/II trial.

PURPOSE: We completed a Phase I/II clinical trial (Lineberger Comprehensive Cancer Center 9603), in which we treated 62 Stage IIIA/IIIB inoperable non-small-cell lung cancer (NSCLC) patients with two cycles of induction carboplatin/paclitaxel chemotherapy, followed by concurrent weekly carboplatin/paclitaxel with radiation doses escalated from 60 to 74 Gy. The median survival of 24 months, 3-year survival rate of 38%, and the high dose of radiation used justified a critical analysis of the technical and clinical components of this trial. METHODS AND MATERIALS: Between 1996 and 1999, 62 sequential patients with inoperable Stage IIIA/IIIB NSCLC were enrolled and treated with two cycles of induction carboplatin (area under the concentration curve = 6 using the Calvert equation) and paclitaxel (225 mg/m(2)), followed by an escalating radiation dose of 60-74 Gy with concurrent carboplatin weekly (area under the concentration curve = 2) and paclitaxel weekly (45 mg/m(2)). The goals of the trial were to determine whether 74 Gy of radiation could be safely delivered under these circumstances and whether patients could potentially benefit in terms of survival. The radiation treatment plans for all 62 patients were reviewed to determine the prechemotherapy and postchemotherapy tumor volume, as well as the dose-volume histograms of the normal lung and esophagus. RESULTS: Of the 62 patients who entered the trial, 48 completed the entire course of treatment. At last follow-up, 20 patients were alive (crude survival rate 32%). With a median follow-up of 43 months, the median survival was 24 months. The survival rate was 50% at 2 years and 38% at 3 years. Cox regression analysis showed that survival was best predicted by whether the patient had received radiotherapy (finished the trial), performance status, disease stage, and log postchemotherapy tumor volume. The 3-year survival rate for the 48 patients finishing the trial was 45%. Eight patients (13%) suffered locoregional relapse as the only site of failure. Only 1 patient had Grade 2 radiation pneumonitis. Five patients (8%) had Radiation Therapy Oncology Group Grade 3 or 4 esophagitis; 40 (65%) had a Grade 1 or 2 esophagitis. Esophageal toxicity could be predicted by the length of esophagus receiving 40 or 60 Gy. CONCLUSION: Radiation doses of 74 Gy, when given under the guidelines of the Lineberger Comprehensive Cancer Center 9603, appear to be safe and may possibly contribute to increased survival in patients with inoperable Stage IIIA/IIIB NSCLC.

Adult↗
PubMed2002

Redox energetics and kinetics of uranyl coordination complexes in aqueous solution.

Detailed voltammetric results for five uranyl coordination complexes are presented and analyzed using digital simulations of the voltammetric data to extract thermodynamic (E(1/2)) and heterogeneous electron-transfer kinetic (k(0) and alpha) parameters for the one-electron reduction of UO(2)(2+) to UO(2)(+). The complexes and their corresponding electrochemical parameters are the following: [UO(2)(OH(2))(5)](2+) (E(1/2) = -0.169 V vs Ag/AgCl, k(0) = 9.0 x 10(-3) cm/s, and alpha = 0.50); [UO(2)(OH)(5)](3-) (-0.927 V, 2.8 x 10(-3) cm/s, 0.46); [UO(2)(C(2)H(3)O(2))(3)](-) (-0.396 V, approximately 0.1 cm/s, approximately 0.5); [UO(2)(CO(3))(3)](4-) (-0.820 V, 2.6 x 10(-5) cm/s, 0.41); [UO(2)Cl(4)](2-) (-0.065 V, 9.2 x 10(-3) cm/s, 0.30). Differences in the E(1/2) values are attributable principally to differences in the basicity of the equatorial ligands. Differences in rate constants are considered within the context of Marcus theory of electron transfer, but no specific structural change(s) in the complexes between the two oxidation states can be uniquely identified with the underlying variability in the heterogeneous rate constants and electron-transfer coefficients.

Journal Article↗
PubMed2002

Steric control of substituted phenoxide ligands on product structures of uranyl aryloxide complexes.

A series of uranyl aryloxide complexes has been prepared via metathesis reactions between [UO(2)Cl(2)(THF)(2)](2) and di-ortho-substituted phenoxides. Reaction of 4 equiv of KO-2,6-(t)()Bu(2)C(6)H(3) with [UO(2)Cl(2)(THF)(2)](2) in THF produces the dark red uranyl compound, UO(2)(O-2,6-(t)()Bu(2)C(6)H(3))(2)(THF)(2).THF, 1. Single-crystal X-ray diffraction analysis of 1 reveals a monomer in which the uranium is coordinated in a pseudooctahedral fashion by two apical oxo groups, two cis-aryloxides, and two THF ligands. A similar product is prepared by reaction of KO-2,6-Ph(2)C(6)H(3) with [UO(2)Cl(2)(THF)(2)](2) in THF. Single-crystal X-ray diffraction analysis of this compound reveals it to be the trans-monomer UO(2)(O-2,6-Ph(2)C(6)H(3))(2)(THF)(2), 2. Dimeric structures result from the reactions of [UO(2)Cl(2)(THF)(2)](2) with less sterically imposing aryloxide salts, KO-2,6-Cl(2)C(6)H(3) or KO-2,6-Me(2)C(6)H(3). Single-crystal X-ray diffraction analyses of [UO(2)(O-2,6-Cl(2)C(6)H(3))(2)(THF)(2)](2), 3, and [UO(2)Cl(O-2,6-Me(2)C(6)H(3))(THF)(2)](2), 4, reveal similar structures in which each U atom is coordinated by seven ligands in a pseudopentagonal bipyramidal fashion. Coordinated to each uranium are two apical oxo groups and five equatorial ligands (3, one terminal phenoxide, two bridging phenoxides, and two nonadjacent terminal THF ligands; 4, one terminal chloride, two bridging phenoxides, and two nonadjacent terminal THF ligands). Apparently, the phenoxide ligand steric features exert a greater influence on the solid-state structures than the electronic properties of the substituents. Emission spectroscopy has been utilized to investigate the molecularity and electronic structure of these compounds. For example, luminescence spectra taken at liquid nitrogen temperature allow for a determination of the dependence of the molecular aggregation of 3 on the molecular concentration. Electronic and vibrational spectroscopic measurements have been analyzed to examine trends in emission energies and stretching frequencies. However, comparison of the data for compounds 1-4 reveals that the innate electron-donating capacity of phenoxide ligands is only subtly manifest in either the electronic or vibrational energy distributions within these molecules.

Journal Article↗
PubMed2002

Enhancing the reactivity of uranium(VI) organoimido complexes with diazoalkanes.

Diphenyldiazomethane effects a two-electron oxidation of the uranium(IV) monoimido complex (C5Me5)2U(=N-2,4,6-t-Bu3C6H2) to give the uranium(VI) mixed bis(imido) complex, (C5Me5)2U(=N-2,4,6-t-Bu3C6H2)(=N-N=CPh2), which undergoes a rare cyclometallation reaction upon mild thermolysis to afford a uranium(IV) bis(amide) complex that results from net addition of a C-H bond of an ortho tert-butyl group across the N=U=N core.

Journal Article↗
PubMedDate not supplied

Combined modality therapy for stage III non-small cell lung cancer.

Lung cancer remains the leading cause of cancer death in the U.S. among both men and women. Approximately 45% of patients present with stage III disease. A proportion of these patients is amenable to surgical resection; however, the majority are "unresectable." For patients with unresectable stage IIIA/B disease, thoracic radiation therapy (TRT) was considered the standard of care until the late 1980s despite a very poor 5-year survival rate. Several clinical trials demonstrated that the combination of chemotherapy and TRT was superior to TRT alone. Based on these data, combined modality therapy became the standard of care for patients with good performance status. Recent trials have shown that concurrent chemoradiotherapy offers a significant survival advantage over sequential chemoradiotherapy. Despite a substantial number of clinical trials, important questions on the optimal treatment paradigm remain. The most effective chemotherapy combination, the use of induction or consolidation chemotherapy in addition to the concurrent portion of therapy, and the optimal dose of chemotherapy with concurrent TRT have yet to be determined. The optimal total dose, fractionation, acceleration, treatment volume, and tumor targeting remain questions related to the TRT portion of therapy. Although significant progress has been made, the majority of patients experience locoregional or distant progression of their disease and die within 5 years of diagnosis. Thus, continued development and participation in clinical trials is crucial to further improvements in the treatment of patients with stage III disease.

Antineoplastic Combined Chemotherapy Protocols↗