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Biomedical subjects

L Miller

Publications and source records attributed to L Miller.

At least 73 records · Page 4Linked to original sources
PubMed2000

Phase I/II trial of irinotecan, carboplatin, and paclitaxel in advanced or metastatic NSCLC.

This multicenter study enrolled 73 patients with locally advanced or metastatic non-small-cell lung cancer (NSCLC). The study design was based on the hypothesis that the non-overlapping toxicities of a 3-drug combination of irinotecan (Camptosar, CPT-11), carboplatin (Paraplatin), and paclitaxel (Taxol) would allow them to be dosed at recommended or standard doses, respectively. Of the 32 patients in phase I portion of the trial, six received irinotecan 40 mg/m2 plus carboplatin at an area-under-curve (AUC) of 6 and paclitaxel 225 mg/m2 on an every-3-week schedule (regimen A). Due to the unexpectedly severe toxicity associated with this regimen, the carboplatin and paclitaxel doses were reduced, while the irinotecan doses were escalated from 40 to 80 to 125 mg and reduced to 100 mg/m2 (regimen B). In the phase II portion of the trial, irinotecan was dosed at 100 mg/m2 because 3 of 8 patients who received the 125 mg/m2 dose in phase I experienced first-course grade 3/4 toxicities. However, the toxicity of regimen B proved unacceptably severe in phase II; 13 of the 40 patients (35%) experienced grade 3/4 neutropenia and 30% suffered febrile or septic neutropenia. The unconfirmed objective response rate in phase I was 64.5%; median time to progression and median survival were 7.1 months and 11.6 months, respectively, and 1-year survival was 46.9%. The unconfirmed objective response rate in phase II was 60.6%, including one complete response (CR) and 19 partial responses (PRs); one CR and 16 PRs were subsequently confirmed. The efficacy and toxicity of this triple combination strongly suggest significant pharmacokinetic and/or pharmacodynamic interactions, warranting continued clinical investigation.

Adult↗
PubMed1999

Preparative chromatographic resolution of enantiomers using polar organic solvents with polysaccharide chiral stationary phases.

The preparative chromatographic resolution of racemic mixtures is rapidly becoming a standard approach for the generation of enantiomers in pharmaceutical research and development. This paper will discuss the optical resolution of numerous pharmaceutical intermediates and final products using polar organic solvents with polysaccharide chiral stationary phases. The advantages of this approach compared to more traditional mobile phases for preparative separations will be presented. In addition the ability to reverse elution order using polar organic solvents will be presented.

Chromatography, High Pressure Liquid↗
PubMed1999

Chromatographic resolution of the enantiomers of a pharmaceutical intermediate from the milligram to the kilogram scale.

The preparative chromatographic resolution of racemic mixtures is rapidly becoming a standard approach for the generation of enantiomers in pharmaceutical R&D. This paper will discuss the optical resolution of a pharmaceutical intermediate as the separation is scaled up from the milligram to the kilogram scale. Difficulties encountered and their solutions at each scale will be discussed. In addition, the exploration of Simulated Moving Bed (SMB) for the separation will also be discussed. Finally, a comparison of the productivities and solvent consumption for each method and scale will be presented.

Chromatography↗
PubMed1999

Peripheral blood allogeneic microchimerism in lung and cardiac allograft recipients.

We have been investigating two parameters, donor antigen-specific hyporeactivity and peripheral blood allogeneic microchimerism, to determine whether these parameters will predict a chronic rejection-free state and which recipients may be candidates for steroid withdrawal. We have identified donor antigen-specific hyporeactivity for 33% (16/48) of lung and 23% (11/47) of heart recipients. For both organ groups, the hyporeactive subgroup experienced a lower incidence of chronic rejection. The probability of donor antigen-specific hyporeactivity predicting a chronic rejection-free state is 100% for lung and 91% for heart recipients. We have identified peripheral blood allogeneic microchimerism for 77% (20/26) of lung and 36% (9/25) of heart recipients tested at 12-18 months posttransplant. Donor antigen-specific hyporeactivity correlates with a critical level of donor cells in lung recipients; the probability of high peripheral blood allogeneic microchimerism levels predicting a chronic rejection-free state in lung recipients is 100%. The results in heart recipients are not as clear with a short-, but not long-term, trend of higher chimerism levels correlating with the development of donor antigen-specific hyporeactivity. These results illustrate the usefulness of immmune parameters to predict long-term graft outcome in an organ-specific manner.

Bronchiolitis Obliterans↗
PubMed1999

Some clinical applications of religious development in adolescence.

The use of religion in the lives of adolescents to repair problematic or disrupted attachments is discussed in the context of attachment theory and Kohut's self-psychology theory, with particular reference to the self-object. It is proposed that adolescents do not seek to break ties with parents or adults so much as to revise their relationships in a more adult direction. Two adolescent cases, one beginning treatment in childhood and the other in early adolescence, are presented and discussed in the context of attachment theory and self-psychology.

Adolescent↗
PubMed1999

Methotrexate compared with mercaptopurine for early induced abortion.

OBJECTIVE: To compare the antimetabolites methotrexate and 6-mercaptopurine as single-agent medical abortifacients using clinical and immunohistochemical analyses. METHODS: Twenty-seven women with gestations less than 7 weeks from the last menstrual period (LMP) were randomized to receive intramuscular methotrexate, 50 mg/m2, or oral 6-mercaptopurine, 200 mg. Forty-six additional women received methotrexate after randomization was discontinued. Women returned at 2-week intervals. Those without fetal cardiac activity were followed until complete abortion. Those with fetal cardiac activity were considered failures and underwent suction abortions. Tissue collected at the time of suction abortion was analyzed with the cell-proliferation immunohistochemical assay Ki-67. RESULTS: All 12 women in the 6-mercaptopurine group had fetal cardiac activity at follow-up and underwent suction abortion; therefore, this arm of the study was discontinued. Six of the 61 women who received methotrexate had fetal cardiac activity at follow-up and also underwent suction abortion. Fetal cardiac activity was present after methotrexate in three of 55 women at less than 6 weeks from the LMP and in three of six between 6 and 7 weeks from the LMP (P < .01). Women who aborted after methotrexate started bleeding on day 19 (standard deviation [SD] 7.8), bled for 9 days (SD 4.0), and used minimal pain medications. Tissues exposed to methotrexate showed decreased Ki-67 activity compared with tissues exposed to 6-mercaptopurine (P = .003). CONCLUSION: In oral doses of 200 mg, 6-mercaptopurine did not induce early abortion. A single intramuscular dose of methotrexate used without prostaglandins induced abortion in most women at gestational ages of less than 6 weeks. Ki-67 activity was lower in a small sample of fetal tissues exposed to methotrexate than in tissues exposed to 6-mercaptopurine.

Abortifacient Agents↗
PubMed1999

Inhibition of stress-activated p38 mitogen-activated protein kinase induces low-density lipoprotein receptor expression.

We have recently shown that different signal transduction pathways initiated by a variety of agents converge on growth-responsive p42/44MAPK signaling cascade to induce low-density lipoprotein (LDL) receptor expression. Our recent demonstration that stress-activated p38MAPK negatively regulates LDL receptor expression in an isoform-specific manner via modulation of p42/44MAPK cascade represents a new dimension of complexity in the molecular communication that governs LDL receptor expression. The suggested one-way communication between p38MAPK and p42/44MAPK provides a potential mechanism for fine-tuning cellular levels of cholesterol in response to a diverse set of environmental cues, including stress. Cross talk between MAPKs opens new avenues toward understanding a variety of pathogenic processes; this makes them tempting targets for therapeutic interventions in cardiovascular diseases.

Animals↗
PubMed1999

Bipartite determinants of DNA-binding specificity of plant basic leucine zipper proteins.

The basic leucine zipper (bZIP) proteins are one of the largest and most conserved groups of eukaryotic transcription factors/repressors. Two major subgroups among the plant bZIP proteins have been identified as G-box (CCACGTGG) or C-box (TGACGTCA) binding proteins based on their DNA binding specificity and the amino acid sequences of their basic regions. We have investigated how plant bZIP proteins determine their DNA binding specificity by mutation of the basic domain of the G-box-binding protein EmBP-1. Four subregions of the EmBP-1 basic domain that differ from the C-box-binding protein TGA1a were substituted singly or in combination with the corresponding regions of TGA1a. DNA binding experiments with the mutant proteins demonstrated that binding specificity of plant bZIP proteins is determined independently by two regions, the core basic region and the hinge region. These two regions have an additive effect on DNA binding specificity. PCR-assisted binding-site selections using key mutants demonstrated that only G-box and C-box binding specificity can be generated by combinations of amino acids in the basic domains of EmBP-1 and TGA1a. These results suggest that factorial contributions of the amino acid residues in the basic domain combine to determine DNA-binding specificity of bZIP proteins.

Amino Acid Sequence↗
PubMed1999

Ethyl-nitrosourea transformed astrocytes exhibit mitochondrial membrane hyperpolarization and constrained apoptosis.

Recent studies have shown the mitochondria and mitochondrial DNA are altered in gliomas, studied either as primary tissues or in culture. Few studies have been performed which evaluate the mitochondria during the development of glial malignancy. We used an ethyl-nitrosourea (ENU) in vitro model to assess the changes in mitochondrial parameters with progression to astrocyte transformation. When compared to the untreated control cells mitochondrial mass of the ENU treated cells significantly decreased ontologically early with concurrent increase in mitochondrial membrane potential, resulting in hyperpolarization of the mitochondrial membrane. At successive divisions, the degree of spontaneous apoptosis during astrocyte transformation was significantly diminished in the ENU treated cells. With 24 h pre- and co-treatment of ENU cells with citrate, an allosteric inhibitor of phosphofructokinase, the astrocytes still became immortal, but did not manifest any of the mitochondrial changes nor acquire the transformed properties of the ENU treated cells without the inhibition. Indeed, the degree of apoptosis noted in these dually treated cells was increased, associated with a loss of anchorage independence and low density growth. Transformed subclones exposed to citrate after the development of malignant properties also exhibited increased apoptosis, and did not form colonies in low density plating conditions. These results suggest that the development of transformed properties in an ENU model is associated with marked hyperpolarization of mitochondrial membrane potential and diminished spontaneous apoptosis. Exposure to citrate attenuated these mitochondrial changes and in vitro growth properties, with increases in apoptosis. The development of transformed astrocytes involve constraints on apoptosis related to alterations in mitochondrial membrane potential and mass.

Journal Article↗
PubMed1999

Mechanical load stimulates expression of novel genes in vivo and in vitro in avian flexor tendon cells.

OBJECTIVE: Our experiments were designed to test the hypothesis that tendon cells might respond differently to applied strain in vitro than in vivo. DESIGN: We tested cells in whole tendons from exercised chickens and from isolated surface (TSC) and internal tendon (TIF) in vitro that were subjected to mechanical strain. We hypothesized that tendon cells differentially express genes in response to mechanical loading in vivo and in vitro. METHODS: We utilized an in-vivo exercise model in which chickens were run on a treadmill in an acute loading regime for 1 h 45 min with the balance of time at rest to 6 h total time. Gene expression was analyzed by a differential display technique. In addition, isolated avian flexor digitorum profundus TSC and TIF cells were subjected to cyclic stretching at 1 Hz, 5% average elongation for 6 h, +/- PDGF-BB, IGF-I, TGF-beta 1, PTH, estrogen, PGE2, or no drug and/or no load. mRNA was then collected and samples were subjected to differential display analysis. CONCLUSIONS: Load with or without growth factor and hormone treatments induced expression of novel genes as well as some known genes that were novel to tendon cells. We conclude that the study of gene expression in mechanically loaded cells in vivo and in vitro will lead to the discovery of novel and important marker proteins that may yield clues to positive and negative cell strain responses that are protective under one set of conditions and destructive under another.

Animals↗
PubMed1999

Chronic pain in the elderly: occupational adaptation as a means of coping with osteoarthritis of the hip and/or knee.

OBJECTIVE: To determine whether elderly individuals with chronic pain as a result of osteoarthritis of the hip and/or knee would report adaptations to their activities, or occupational adaptations, as a coping response to pain and, if so, to describe these adaptations and their relation to chronic pain, functional difficulty, depression, social support, and life satisfaction. DESIGN: Thirty elderly individuals completed rating scales and a structured questionnaire designed to measure occupational adaptation and the importance of activity. SETTING: Participants were community-dwelling elderly individuals and were interviewed in their homes or in a research office setting. PATIENTS: Consecutive orthopedic surgeon, family physician, or Arthritis Society patients, whose names were provided with the patient's consent, to the researcher. RESULTS: Individuals reported two approaches to occupational adaptation: they changed how they performed personal activities of daily living that they rated as most important and they stopped performing a number of avocational activities that they rated as less important. Statistically significant correlations were found among occupational adaptation, pain, depression, and difficulty with functioning. These variables were inversely related to life satisfaction. CONCLUSIONS: This sample of elderly individuals with chronic pain described occupational adaptations, or adaptations to "doing," as a means of coping with their chronic pain. There appeared to be a relation among pain, functional difficulty, depression, social support, and occupational adaptation. Additional research to increase the understanding of occupational adaptation as a means of coping with chronic pain is warranted.

Activities of Daily Living↗
PubMed1999

Multicenter, phase II trial of exemestane as third-line hormonal therapy of postmenopausal women with metastatic breast cancer. Aromasin Study Group.

PURPOSE: To assess the antitumor activity, safety, and hormone-suppressive effects of the irreversible aromatase inactivator, exemestane (Aromasin, Pharmacia & Upjohn, Kalamazoo, MI), administered as third-line hormone therapy to postmenopausal women with metastatic breast cancer that is refractory to tamoxifen and megestrol acetate. PATIENTS AND METHODS: Exemestane was administered at a dose of 25 mg/d orally until patients experienced disease progression. The efficacy and safety of exemestane were clinically and radiographically evaluated. The impact of exemestane treatment on tumor-related signs and symptoms was assessed. The effect of exemestane on serum levels of estrogens and other steroidal hormones was determined. RESULTS: Ninety-one patients were treated. There were four complete responses (CR) and eight partial responses (PR), for an objective response rate of 13% in the entire treated population. The overall success rate (CR, PR, or stable disease [SD] >/= 24 weeks) was 30%. The median duration of response and overall success was 9 months and 8 months, respectively. Most patients with CR/PR (83%; 10 of 12 patients) and SD >/= 24 weeks (80%; 12 of 15 patients) had improved or stable tumor-related signs and symptoms. Mean levels of circulating estrone (E(1)), estradiol (E(2)), and estrone sulfate decreased to 11%, 22%, and 13% of baseline levels, respectively (at week 8 or 16 of treatment). One half of the patients had undetectable E(1) and E(2) levels during treatment, including at the time of disease progression. Mild nausea (20% of patients) and hot flashes (20%) were the most common drug-related adverse events and were generally grade 1. CONCLUSION: Exemestane is an active and well-tolerated third-line hormonal therapy that represents a new treatment option for postmenopausal patients with advanced breast cancer that has become refractory to standard first- and second-line hormonal therapies.

Adult↗
PubMed1999

Evaluation of a new universal jettison mechanism for helicopter underwater escape.

BACKGROUND: To date, there is no standard jettison mechanism for doors, windows, or hatches in ditched helicopters. A new Universal Escape Exit (UEE) has been invented and the performance has been compared with two current in-service systems in a helicopter underwater escape trainer. METHOD: A total of 416 evacuations were conducted by 40 subjects in two experiments using the Survival Systems Limited's underwater escape trainer. RESULTS: The UEE had a distinct 2-s advantage to escape; and, in the majority of cases, was preferred to a rotating lever or a straight push out system. CONCLUSIONS: Further work should continue with UEE development for qualification in an operational helicopter.

Accidents, Aviation↗