Biomedical subjects

Michael Stevens

Publications and source records attributed to Michael Stevens.

5 recordsLinked to original sources

PubMed2026

Longitudinal dynamics of gene expression and metabolomics in an aging population cohort.

Multiomic profiling provides a comprehensive physiological overview at the molecular level, but understanding of its spatiotemporal dynamics remains limited in human populations. We profiled longitudinal whole-blood gene expression and metabolite levels in 335 females over 8 years. Levels of 5061 genes and 181 metabolites changed over time, with individual trajectories often diverging from population-level trends. Longitudinally variable genes showed cell type specificity and enrichment for aging-relevant pathways, including cardiometabolic and neurodegenerative disorders. Longitudinal trajectories were further shaped by genetics, circadian rhythm, seasonality, and environmental pollutant exposures. Integrative analyses revealed extensive static and time-variable cross-omic connectivity. Longitudinal profiling offers insight into the temporal evolution of age-related conditions at the molecular level, and understanding individual variation within these longitudinal patterns will be essential for future precision medicine approaches.

Female↗

PubMed2002

Once-daily quadruple-drug therapy with adefovir dipivoxil, Lamivudine, Didanosine, and efavirenz in treatment-naive human immunodeficiency virus type 1-infected patients.

A 48-week open-label study of 11 antiretroviral-naive, human immunodeficiency virus type 1 (HIV-1)-infected adults evaluated once-daily treatment with adefovir dipivoxil, lamivudine, didanosine, and efavirenz. At baseline, the median plasma HIV-1 RNA level was 4.99 log(10) copies/mL, and the median CD4 cell count was 471 cells/mm(3). At 24 and 48 weeks after initiation of treatment, median HIV-1 RNA levels decreased from baseline by 4.77 and 4.99 log(10) copies/mL, respectively, and median CD4 cell counts increased by 135 and 177 cells/mm(3), respectively. The regimen was generally well tolerated. No patients withdrew from the study because of adverse events. However, 7 patients developed adefovir-related nephrotoxicity after >/=20 weeks of treatment; this resolved without sequelae after adefovir was discontinued. Overall adherence was 85%. Once-daily quadruple-drug therapy with adefovir, lamivudine, didanosine, and efavirenz provides pronounced and durable suppression of HIV-1 RNA and elevation of CD4 cell counts over the course of 48 weeks, with generally good tolerability and adherence.

Adenine↗

PubMed2002

One-step synthesis and structure of an oligo(spiro-orthocarbonate).

The reaction of pentaerythritol and tetraethylorthocarbonate at 260 degrees C for 12 h yields a white crystalline material that was characterized by 13C CPMAS NMR, CHN analysis, FT-IR, electron and X-ray powder diffraction, and Rietveld analysis. The white crystalline material was found to have the formula C6H8O4 and a crystal structure with a monoclinic cell [a = 9.167 A, b = 5.681 A, c = 5.880 A, beta = 90.0 degrees , space group I2] of hexagonally arranged spiro-oligomeric chains.

Journal Article↗

PubMed2002

Supportive use of megestrol acetate (Megace) with head/neck and lung cancer patients receiving radiation therapy.

PURPOSE: The purpose of this study was to measure the effect of megestrol acetate (MA) on weight loss and quality of life (QOL) in patients with cancer of the lung or head and neck undergoing curative radiation therapy. METHODS AND MATERIALS: This was a Phase III, placebo-controlled, double-blind randomized study. Patients received either 800 mg/day of MA (20 milliliters po qAM) or placebo over a 12-week period. Patients received radiation of the head and neck or thorax using a dose of at least 50 Gy, either alone or with chemotherapy. Weight was assessed weekly, whereas QOL was assessed at baseline and at 4, 8, and 12 weeks. RESULTS: Patient characteristics on the MA arm (16 lung, 12 head/neck; mean age: 60 years) were similar to those on the placebo arm (17 lung, 11 head/neck; mean age: 65.8 years). Patients in the MA group had a mean weight loss over 12 weeks of 2.7 pounds, whereas the placebo group had a mean weight loss of 10.6 pounds. There was a significant time by treatment interaction (p = 0.001), with the difference in weight between treatment groups being most pronounced after 6 weeks. Although overall QOL was similar in both arms of the study, several QOL subscale items did differ significantly. Compared to the placebo-treated patients, head-and-neck cancer patients in the MA arm reported the ability to eat as much as they liked (p = 0.02 at 12 weeks), and lung cancer patients in the MA arm reported significantly better appetite at 4 weeks (p = 0.03) and 8 weeks (p = 0.001). CONCLUSION: MA used prophylactically is useful as an appetite stimulant; it can help patients maintain weight over the course of curative radiotherapy of the head and neck or lung and can improve specific aspects of QOL.

Adult↗

PubMedDate not supplied

Traditional sampling with laboratory analysis and solid phase microextraction sampling with field gas chromatography/mass spectrometry by military industrial hygienists.

The opinions or assertions contained herein are the private ones of the authors and are not to be construed as official or reflecting the views of the United States Department of Defense or the Uniformed Services University of the Health Sciences. Rapid on-site detection and identification of environmental contaminants to which personnel may be exposed is often needed during military deployment situations. The availability of military industrial hygienists with capabilities for "complete" on-site exposure assessment of chemical species should allow detection and identification of a number of important stressors almost immediately following sample collection. Portable gas chromatography/mass spectrometry (GC/MS) provides a rapid and efficient separation of volatile and semivolatile organic analytes, accompanied by sensitive electron impact ionization-mass spectrometry (EI-MS) detection. The use of GC/MS in the field is limited, however, by equipment cost, complexity of the equipment, and the analytical process. Additionally, a skilled operator is needed to obtain useful separations and to interpret mass spectral data. To demonstrate benefits and limitations of "complete" exposure assessment capabilities, a previously unidentified complex mixture, produced by thermal dispersion of riot control agents, was examined. Established active sampling methods were used with laboratory analyses. Solid phase microextraction, a passive sampling method that simplifies preparation for GC/MS analysis, also was used with a field-portable GC/MS system. Both sampling/analysis methods were used to detect CS riot control agent-derived air contaminants dispersed from riot control type canisters through oxidizer-supported combustion of a chemical fuel.

Chemistry Techniques, Analytical↗