Expanding the product portfolio of carbon dioxide and hydrogen-based gas fermentation with an evolved strain of Clostridium carboxidivorans.

CO2:H2-based gas fermentation with acetogenic Clostridium species are at an early stage of development. This work exploited the Adaptive Laboratory Evolution technique to improve the growth of C. carboxidivorans P7 on CO2 and H2. An adapted strain with decreased growth lag phase and improved biomass production was obtained. Genomic analysis revealed a conserved frameshift mutation in the catalytic subunit of the hexameric hydrogenase gene. The resulted truncated protein variant, most likely lacking its functionality, suggests that other hydrogenases might be more efficient for H2-based growth of this strain. Furthermore, the adapted strain generated hexanol as primary fermentation product. For the first time, hexanol was produced directly from CO2:H2 blend, achieving the highest maximum productivity reported so far via gas fermentation. Traces of valerate, pentanol, eptanol and octanol were observed in the fermentation broth. The adapted strain shows promising to enrich the product spectrum targetable by future gas fermentation processes.

Return to work after organ transplantation: a cross-sectional study on working ability evaluation and employment status.

INTRODUCTION: Organ transplantation has increased in Italy over the last decade. Thus, an increasing number of workers may face the problem of returning to work. The aim of this study was to provide an assessment of working ability of transplant recipients in comparison with their actual employment status. METHODS: This study was based on 150 patients who underwent transplantation since 1994 and who underwent periodic post-transplantation examination during 2012. Fifty patients who had undergone heart transplantation (HT), 50 liver transplantation (LT), and 50 kidney transplantation (KT) and survived at least 12 months after surgery were eligible for this study. All patients underwent the International Classification of Functioning, Disabilities and Health (ICF) questionnaire; ten questions were further applied to those who were employed at the time of the study. X(2) statistics were used to compare working ability evaluation and employment status and for internal comparison among different organ recipients. RESULTS: The employment status was as follows: 92 (61%) patients were in paid employment, 6 (4%) were students or housewives, 36 (24%) were unemployed, and 17 (11%) were retired because of invalidity benefits. According to our fitness evaluation only 4% to 10% of the patients were unfit for any job. When we excluded retired subjects, the X(2) statistics for correlated observations showed a highly significant statistical difference (P < .0001) between unemployed and unfit. As a result of the ICF questionnaire administration, there was a marked difference, although not statistically significant, in the fitness for previously performed jobs between KT and LT recipients (62% and 58%, respectively) and HT recipients (42%). DISCUSSION AND CONCLUSION: In this cross-sectional study we found a relatively high rate of unemployment as compared with the working ability evaluation by ICF questionnaire and other questions. This may be due to several factors including health status and the possibility of gaining an adequate job. The ICF questionnaire proved to be a useful framework that can be used for research but also by occupational physicians in their usual practice after specific training.

Pharmacokinetics of diclofenac after oral administration of its potassium salt in sachet and tablet formulations.

This paper reports the results of a pharmacokinetic study involving 24 healthy volunteers and designed to characterise the rate and extent of diclofenac absorption after the administration of a single dose of diclofenac (CAS 15307-86-5) potassium salt 50 mg in sachet (Voltfast) and tablet (Cataflam) formulations. Timed plasma concentrations of diclofenac during a 12-h-period after dosing were measured by means of HPLC with UV detection at 275 nm and a quantification limit of 10 ng/ml; the method was fully validated for pharmacokinetic purposes. These plasma concentrations were used to calculate Cmax, tmax, trapezoidal AUC0-t and AUC0-infinity and t1/2 by means of noncompartmental analysis. Cmax and tmax are the parameters expressing the rate of absorption, whereas the AUCs reflect the extent of absorption. The rate of absorption with the sachets proved to be very fast, reaching peak values at 10 min in seven subjects and at 15 min in the remaining subjects: mean time was 13.68 min, with concentrations at 5 min being 38% of Cmax. The average time to peak concentration with the tablets was 53.10 min. The extent of absorption of the sachets and tablets was similar, with AUC0-infinity values of respectively 1362 and 1214 ng.ml-1.h, and a 90% confidence interval 1.05-1.20. The highly soluble potassium salt of diclofenac was rapidly absorbed, especially in its sachet formulation, and thus appears to be an invaluable analgesic agent that is particularly useful for quick pain relief.

Gas chromatographic assay for estazolam in human plasma and results of a bioequivalence study.

This paper describes a new sensitive gas chromatographic method with electron capture detector to assay estazolam in human plasma, which has been developed and validated for pharmacokinetic purposes. The drug and the internal standard (triazolam) were extracted from plasma buffered at pH 9.0 into toluene and analysed on a widebore DB 17 column. The calibration curve covered the 1.0-200 ng ml-1 range with a mean determination coefficient of 0.9996. The quantification limit was 1.0 ng ml-1. This method was used to investigate the bioequivalence of a new formulation of estazolam in drops (test) and the formulation in tablets (reference, ESILGAN). Both formulations were administered at a single dose of 2 mg in a clinical trial carried out on 24 healthy volunteers consisting of 12 males and 12 females, following a crossover randomised design in two periods with wash-out. The test and the reference formulations proved to be fully bioequivalent according to operating guidelines, namely through 90% confidence intervals in the 0.80-1.25 range.

Determination of ticlopidine in human plasma by high-performance liquid chromatography and ultraviolet absorbance detection.

A simple HPLC method has been developed for the determination of ticlopidine in human plasma. Plasma samples were buffered at pH 9 and extracted with n-heptane-isoamyl alcohol (98.5:1.5, v/v). Imipramine was used as internal standard. Chromatography was performed isocratically with acetonitrile-methanol-0.05 M KH2PO4 (20:25:55, v/v) at pH 3.0 containing 3% triethylamine at a flow-rate of 1 ml/min. A reversed-phase column, Supelcosil LC-8-DB, 15 cm x 4.6 mm I.D., 5 microns particle size, was used. The effluent was monitored by UV absorbance detection at 235 nm. The method showed good accuracy, precision and linearity in the concentration range 5-1200 ng/ml. The limit of quantitation was 5 ng/ml, with a precision (C.V.) of 8.91%, which is the same as that achieved by other authors with a previously published GC-MS method. The procedure described in this paper is simple and allows the routine assessment of ticlopidine plasma concentration in pharmacokinetic studies following therapeutic doses in human subjects.

Determination of 2'-deoxy-5-iodouridine and its metabolite 5-iodouracil by high-performance liquid chromatography with ultraviolet absorbance detection in human serum.

A new assay is described for 2'-deoxy-5-iodouridine, a drug employed as an antiviral agent by topical application. The parent drug, its systemic metabolite 5-iodouracil and an internal standard (5-iodouridine) were extracted from salted serum by an ethyl acetate partition at pH 6.7, back-extracted in alkalinized water and injected into a reversed-phase column. Potassium phosphate buffer-acetonitrile (95:5, v/v) eluted the analytes at a flow-rate of 1.5 ml/min. Detection was at 290 nm. The method proved to be linear in the 100-2000 ng/ml range.