Successful aging in America, Part I. Nutrition, the elderly, and the laboratory

Laboratory testing should be integral to nutrition-related services, including screening, assessment, and monitoring for both inpatient and outpatient geriatric populations. Find out how the laboratory can contribute to the improved health of seniors and reduce overall healthcare costs through nutritional status assessment and monitoring.     

Transforming the long-term care system: policy and managerial challenges

As the need for long-term care of people with disabilities increases, the model of care faces crucial changes, including a shift from institutional to independent living, significant changeover in organizational auspices, and policies created by the Americans with Disabilities Act. Such systemic changes pose fiscal, technological, and social challenges to policymakers and managers of care delivery.     

An experimental investigation of the spray issued from a pMDI using laser diagnostic techniques.

This research was concerned with the experimental investigation of the spray issued from a pressurised metered-dose inhaler (pMDI) using laser diagnostic techniques and has been motivated by the urgent need to find suitable replacements to the environmentally destructive CFC propellants currently used in the device. The experimental work was conducted using phase-Doppler particle analysis (PDPA), a single particle light scattering technique that provides the simultaneous measurement of drop size, velocity, and concentration, yielding the most detailed temporal and spatial analysis of the pMDI spray to date. Three formulations were studied to compare the performance of an "ozone-friendly" hydrofluoroalkane propellant against that of a traditional CFC propellant mixture and a commercially available CFC formulation containing drug and surfactant. The PDPA analysis was complemented by a visual investigation of the near-orifice flow field using copper laserstrobe microcinematography to obtain information on the primary atomization process of the pMDI. This work was conducted in parallel with the theoretical investigation of the spray issued from a pMDI.     

Characterization of the trp5-27 allele used to monitor drug-induced mitotic gene conversion in the Saccharomyces cerevisiae tester strain D7

Mitotic gene conversions, among other recombinagenic events,can play an important role in the multistep process of carcinogenesis.The ability of chemicals to induce such gene conversions caneasily be monitored in the Saccharomyces cerevisiae tester strainYHE2, a derivative of strain D7. For the detection of drug-inducedgene conversions, two mutations in the TRP5 locus are used,trp5–12 and trp5–27. Here we report on the characterizationof the stable allele trp5–27. Our analysis revealed tworelevant mutations in trp5–27: (a) a transition C to Tat position 121 after ATG that results in an amber stop codonand abolishes gene expression and (b) a transversion A to Tat position 1555 that creates an ochre stop codon. Simultaneousamber and ochre suppression with the suppressors SUP3 and SUP11,respectively, was capable of relieving the tryptophan-requiringphenotype of strains carrying the trp5–27 allele. Thesefindings have implications on the length of gene conversiontracts in conversion events between trp5–12 and trp5–27:conversion tracts can cover several kilobases, if the site ofthe mutation in trp5–12 lies outside of the positionsmutated in trp5–27. Conversely, the maximal length islimited to 1435 bp, if the mutation in trp5–12 is locatedbetween the positions mutated in trp5–27. ¹To whom correspondence should be addressed     

Phenotypic correction of Fanconi anemia in human hematopoietic cells with a recombinant adeno-associated virus vector.

Fanconi anemia (FA) is a recessive inherited disease characterized by defective DNA repair. FA cells are hypersensitive to DNA cross-linking agents that cause chromosomal instability and cell death. FA is manifested clinically by progressive pancytopenia, variable physical anomalies, and predisposition to malignancy. Four complementation groups have been identified, termed A, B, C, and D. The gene for the FA complementation group C, FACC, has been cloned. Expression of the FACC cDNA corrects the phenotypic defect of FA(C) cells, resulting in normalized cell growth in the presence of DNA cross-linking agents such as mitomycin C (MMC). Gene transfer of the FACC gene should provide a survival advantage to transduced hematopoietic cells, suggesting that FA might be an ideal candidate for gene therapy. We demonstrated efficient transduction, expression, and phenotypic correction in lymphoblastoid cell lines derived from FA (C) patients using a recombinant adeno-associated virus (rAAV) vector containing the FACC gene. Molecular characterization of the transduced FACC gene showed an intact unrearranged proviral genome with expression sufficient to normalize cell growth, cell cycle kinetics and chromosomal breakage in the presence of MMC. These observations were extended by testing rAAV transduction in hematopoietic progenitor cells. Peripheral blood CD34+ cells isolated from a FA (C) patient and transduced with rAAV/FACC virus yielded 5-10-fold more progenitor colonies than mock-infected cells, consistent with genetic "rescue" of corrected cells. This is the first demonstration of rAAV gene correction in primary human hematopoietic progenitor cells and has important implications for gene therapy of hematopoietic disorders, specifically FA.     

Optimizing sedation following major vascular surgery: a double-blind study of midazolam administered by continuous infusion

A randomized, double-blind study was undertaken to determine the dose requirements, recovery characteristics, and pharmacokinetic variables of midazolam given by continuous infusion for sedation in patients following abdominal aortic surgery. Thirty subjects, 50–75 yr, scheduled to undergo aortic reconstructive surgery, entered the study. Following a nitrous oxide-isoflurane-opioid anaesthetic technique, patients were randomly allocated to receive one of three loading doses (0.03, 0.06 or 0.1 mg · kg^?1) and initial infusion rates (0.5, 1.0 or 1.5 μg · kg^?1 · min^?1) of midazolam, corresponding to groups low (L), moderate (M) and high (H). The infusion of midazolam was adjusted to maintain sedation levels of “3, 4 or 5,“ which permitted eye opening in response to either verbal command or a light shoulder tap, using a seven-point scale ranging from “0” (awake, agitated) to “6” (asleep, non-responsive). Additionally, morphine was given in increments of 2.0 mg iv prn for analgesia. On the morning after surgery, midazolam was discontinued, and the tracheas were extubated when patients were awake. Blood samples were taken during, and at increasing intervals for 48 hr following discontinuation of the infusion, and analyzed by gas chromatography. The desired level of sedation was maintained during more than 94% of the infusion period in all three groups, with a maximum of three dose adjustments per patient, for treatment which lasted 16.3 ± 0.6 hr. There was, however, an increase in both the infusion rates and mean plasma concentrations from Group L to Group H (P < 0.05), which corresponded to an inverse relationship of morphine requirements during the period of sedation (P < 0.05, Group H vs Group L). Optimal midazolam infusion rates and resulting plasma concentrations at the times the infusions were discontinued (in parentheses) were as follows — Group L: 0.60 ± 0.18 μg · kg^?1 min^?1 (76 ± 32 ng · mL^?1), Group M: 0.90 ± 0.52 μg · kg^?1 · min^?1 (133 ± 71 ng · mL^?1), and Group H: 1.34 ± 0.69 μg · kg^?1 · min^?1 (206 ± 106 ng · mL^?1). Times to awakening were longer in Group H: 3.1 ± 3.4 hr, than in Group L: 1.1 ± 0.8 h, P < 0.05. Pharmacokinetic variables were found to be dose- independent over the range of infusion rates. Mean values were t_1/2β = 4.4 ± 1.5 hr, CL = 5.94 ± 1.69 mL · min^?1 · kg^?1, Vd = 3.13 ± 1.07 L · kg^?1. It is concluded that midazolam, infused between 0.6–0.9 μg · kg^?1 · min^?1, provides a stable level of sedation, when administered in conjunction with intermittent iv morphine following AAS. This sedation technique, which costs $1.65 ± 0.73 hr^?1 ($Can), is associated with rapid recovery and minimal side effects.     

Characterization of cytochrome P4501A induction in medaka (Oryzias latipes) by samples generated from the extraction and processing of coal

The objective of this study was to characterize cytochrome P4501A induction in medaka liver as a biomarker for detecting polyaromatic hydrocarbon (PAH)-type compounds in samples of processed coal or petroleum. Ethoxyresorufin-O-deethylase (EROD) activity in individual medaka livers was used to assess induction of P4501A following the addition of various samples to aquaria water. Samples included a known P4501A inducer, -naphthoflavone, and various processed coal samples, as well as a petroleum-pitch. The sensitivity of detecting significant EROD induction by adding samples to aquaria water was 0.1 mg/L for most samples; however, a coal-tar pitch significantly increased EROD activity at 0.01 mg/L. Different samples induced EROD activity to different extents. All samples elicited a concentration-dependent increase in EROD activity, with maximum EROD induction 2 days after a single administration of xenobiotics to aquaria water. Western blot studies established that induction of EROD activity by all xenobiotics tested was associated with corresponding increased amounts of immunoreactive P4501A. EROD induction was not influenced by gender, by single or multiple xenobiotic exposures, nor by feeding or fasting animals during the course of xenobiotic exposure. The ability of xenobiotics to induce EROD activity in medaka liver did not always correlate with their genotoxic potential determined by bacterial mutagenesis assays. Induction of P4501A in medaka liver appears to provide a convenient, economical, reliable and sensitive indicator for the presence of PAH-type compounds in coal- or petroleum-derived samples.Abbreviations BNF -naphthoflavone - CTP coal tar pitch - DMSO dimethylsulfoxide - EROD ethoxyresorufin-O-deethylase - H400 test sample hydrogenated at 400°C - H450 test sample hydrogenated at 450°C - SDS PAGE sodium dodecyl sulphate polyacrylamide gel electrophoresis - PP petroleum pitch - DMEM Dulbecco's Modified Eagles Medium