A rapid and precise method for the isolation of vitamins A and E and their acetate or palmitate esters from table matrices was developed using supercritical fluid extraction (SFE). The vitamins were ...analyzed by nonaqueous reversed-phase high-performance liquid chromatography after a 15-min extraction of the dosage form with supercritical carbon dioxide at 40 degrees C and at a pressure of 250 atm. A quantitative comparison of SFE with an established liquid extraction procedure was performed on commercial tablet formulations. Vitamin recoveries of over 95.6% compared with conventional liquid extraction were achieved by the SFE technique with a much shorter sample preparation time (15 min vs 2h). Moreover, the automated SFE process minimized the number of sample handling operations, drastically reduced the consumption of harmful solvents, and provided mild extraction conditions for the analysis of the labile vitamins. The described SFE method is suitable for quality control analyses of pharmaceutical tablets.
Background. Results of valvular reoperations depend on extrinsic and patients’ intrinsic risk factors. New prosthetic substitutes continue to appear and the clinical effect is difficult to evaluate. ...Randomized studies are limited by patient selection and follow-up time. We followed the patient-centric outcome research applied to a large database of valvular operations.
Methods. Between January 1, 1970 and January 1, 1995 755 patients underwent one reoperation, 96 a second reoperation, and 12 a third reoperation. On January 1, 1996 a common closing date follow-up was obtained in 98.7% of reoperated patients. Multivariable analysis in the hazard domain was applied to obtain an upgradable model of survival that could be used for predictions and treatment comparison.
Results. Postoperative death hazard showed an early phase merging within 6 months with a constant low hazard phase. The survival proportion was 0.65 (70% CL, 0.63 to 0.67) at 5 years, 0.51 (70% CL, 0.49 to 0.53) at 10 years, 0.47 (range, 0.44 to 0.49) at 15 years, 0.42 (70% CL, 0.39 to 0.46) at 20 and 25 years. Significant incremental risk factors for early mortality were reoperative era 1970 to 1980 (hazard ratio = 2.8), reoperation number (hazard ratio = 1.9), heart penetration on surgery (hazard ratio = 7.6), emergent operation (hazard ratio = 5.8), urgent operation (hazard ratio = 2.1), prosthetic thrombosis (hazard ratio = 2.4), acute prosthetic endocarditis (hazard ratio = 3.0), acute endocarditis of the natural valve at antecedent operation (hazard ratio = 3.2), original floppy valve pathology (hazard ratio = 3.2), and mitroaortic replacement (hazard ratio = 5.7). Isolated mitral reoperation had a lower risk (hazard ratio = 0.5). Significant incremental risk factors for constant phase were: operative era (1970 to 1980) (hazard ratio = 2.0), congestive heart failure (hazard ratio = 2.6), reoperation on tricuspid valve after previous mitral insertion (hazard ratio = 4.9), reoperation for recurring dehiscence (hazard ratio = 4.6), double-valve procedure (hazard ratio = 1.6), coronary artery bypass graft (hazard ratio = 2.7), aortic root disease at original operation (hazard ratio = 2.1), older operative age (hazard ratio = 1.1). Use of bileaflet prosthesis was found to decrease significantly (
p = 0.0002) the death risk (hazard ratio = 0.2).
Conclusions. There is no late uprising hazard, and surviving patients remain exposed to a low risk of death (4% of patients per year). Considering simultaneously the confounding from operative age and operative era and the many concomitant risk factors, survival appears favorably influenced by use of bileaflet valves on reoperation.
A highly sensitive and selective method for the determination of sorbic (SA) and undecylenic acid (UA) in cosmetic formulations by a high performance liquid chromatography method with electrochemical ...detection (ECD) is described. The pre-column derivatizations of SA and UA and the internal standard (cyclohexanoic acid (cHA)) were carried out using 1-(2,5-dihydroxyphenyl)-2-bromoethanone (2,5-DBE) as an electroactive labeling reagent previously synthesized in our lab. The resulting electroactive esters were separated by isocratic elution of a 5 μm Hypersil CN column with acetonitrile–acetate buffer eluent. The compounds were detected by a porous graphite electrode set at an oxidation potential of +0.45 V. The analytical method developed in this study is suitable for quality control assays of complex cosmetic formulations containing sorbic and/or UA.
An acoustic high-throughput screening method is described for harvesting protein crystals and combining the protein crystals with chemicals such as a fragment library. Acoustic droplet ejection (ADE) ...is an emerging technology with broad applications in serial crystallography such as growing, improving and manipulating protein crystals. One application of this technology is to gently transfer crystals onto MiTeGen micromeshes with minimal solvent. Once mounted on a micromesh, each crystal can be combined with different chemicals such as crystal-improving additives or a fragment library. Acoustic crystal mounting is fast (2.33 transfers s{sup −1}) and all transfers occur in a sealed environment that is in vapor equilibrium with the mother liquor. Here, a system is presented to retain crystals near the ejection point and away from the inaccessible dead volume at the bottom of the well by placing the crystals on a concave agarose pedestal (CAP) with the same chemical composition as the crystal mother liquor. The bowl-shaped CAP is impenetrable to crystals. Consequently, gravity will gently move the crystals into the optimal location for acoustic ejection. It is demonstrated that an agarose pedestal of this type is compatible with most commercially available crystallization conditions and that protein crystals are readily transferred from the agarose pedestal onto micromeshes with no loss in diffraction quality. It is also shown that crystals can be grown directly on CAPs, which avoids the need to transfer the crystals from the hanging drop to a CAP. This technology has been used to combine thermolysin and lysozyme crystals with an assortment of anomalously scattering heavy atoms. The results point towards a fast nanolitre method for crystal mounting and high-throughput screening.
Contraception is recommended for female patients during ursodeoxycholic acid (UDCA) treatment for the potential teratogenic effect of this bile acid, and the aim of our study was to determine whether ...this treatment affects the bioavailability of ethinylestradiol (EE2).
In this double-blind, randomised study, we measured EE2 pharmacokinetics in eight healthy volunteers randomly allocated to receive oral contraceptive (30 microg EE2 and 75 microg gestodene) plus either UDCA (8-10 mg/kg per day) or placebo for 21 days during the first of three consecutive menstrual cycles. After a washout period during the second cycle, the subjects received the alternative treatment during the third menstrual cycle. Serum EE2 and UDCA were measured using radioimmunoassay and gas chromatography-mass spectrometry, respectively.
The profile for serum EE2 concentration was similar during UDCA (mean maximum serum concentration 177 pg/ml, SEM 59) and during placebo treatment (153 pg/ml, SEM 62), and mean area under the curve (AUC) was 1374 pg/h per ml (SEM 580) and 1320 pg/h per ml (SEM 551) during the two regimens, respectively. The point estimates and 90% confidence intervals of UDCA/placebo ratios for EE2 AUC and for maximum serum concentration were 1.1 (0.8-1.5) and 1.2 (1.0-1.4), respectively. Mean serum triglycerides concentration increased from 58.3 mg/dl (SEM 6.8) at enrolment to 91.4 mg/dl (SEM 10.7) during placebo (P < 0.01) and to 88.6 mg/dl (SEM 13.7) during UDCA treatment (P < 0.05). During UDCA treatment, serum enrichment with this bile acid and with the metabolite iso-UDCA was 29% (16%) and 3% (2%), respectively.
Co-administration with UDCA does not affect the bioavailability of EE2 in healthy volunteers, indicating that contraceptive efficacy is not affected.
This paper provides experimental evidence that "weird'/poor outdoor link-level performance measurements may be caused by driver/card-specific antenna diversity algorithms unexpectedly ...supported/activated at the WLAN transmitter side. We focus our analysis on the Atheros/MADWiFi card/driver case, and we observe that the transmit antenna diversity mechanisms remain by default enabled when the available antennas are not homogeneous in terms of gain or, even worse, when only a single antenna is connected. This may cause considerable performance impairments (large frame loss ratio), in conditions frequently encountered in outdoor link deployments. The negative impact of transmit antenna diversity is not limited to the transmission of broadcast frames (where a cyclic shift between the "two" assumed antennas is performed), but under certain circumstances it can severely affect the delivery of unicast frames as well, and despite the fact that in this case the ACK receptions may provide a feedback about the best receiving antenna. While, as obvious, driver developers are expectedly fully aware of the existence of such mechanisms, we believe that the scientific research community has very limited awareness of the implications these mechanisms have on the measured link-level performance. Indeed, to the best of our knowledge, ours is the first research paper which explicitly raises this issue.
By using the methodology of both wet and dry biology (i.e., RT-PCR and cycle sequencing, and biocomputational technology, respectively) and the data obtained through the Genome Projects, we have ...cloned Xenopus laevis SOD2 (MnSOD) cDNA and determined its nucleotide sequence. These data and the deduced protein primary structure were compared with all the other SOD2 nucleotide and amino acid sequences from eukaryotes and prokaryotes, published in public databases. The analysis was performed by using both Clustal W, a well known and widely used program for sequence analysis, and AntiClustAl, a new algorithm recently created and implemented by our group. Our results demonstrate a very high conservation of the enzyme amino acid sequence during evolution, which proves a close structure-function relationship. This is to be expected for very ancient molecules endowed with critical biological functions, performed through a specific structural organization. The nucleotide sequence conservation is less pronounced: this too was foreseeable, due to neutral mutations and to the species-specific codon usage. The data obtained by using AntiClustAl are comparable with those produced with Clustal W, which validates this algorithm as an important new tool for biocomputational analysis. Finally, it is noteworthy that evolutionary trees, drawn by using all the available data on SOD2 nucleotide sequences and amino acid and either Clustal W or AntiClustAl, are comparable to those obtained through phylogenetic analysis based on fossil records.
A method is presented for screening fragment libraries using acoustic droplet ejection to co-crystallize proteins and chemicals directly on micromeshes with as little as 2.5 nl of each component. ...This method was used to identify previously unreported fragments that bind to lysozyme, thermolysin, and trypsin. Acoustic droplet ejection (ADE) is a powerful technology that supports crystallographic applications such as growing, improving and manipulating protein crystals. A fragment-screening strategy is described that uses ADE to co-crystallize proteins with fragment libraries directly on MiTeGen MicroMeshes. Co-crystallization trials can be prepared rapidly and economically. The high speed of specimen preparation and the low consumption of fragment and protein allow the use of individual rather than pooled fragments. The Echo 550 liquid-handling instrument (Labcyte Inc., Sunnyvale, California, USA) generates droplets with accurate trajectories, which allows multiple co-crystallization experiments to be discretely positioned on a single data-collection micromesh. This accuracy also allows all components to be transferred through small apertures. Consequently, the crystallization tray is in equilibrium with the reservoir before, during and after the transfer of protein, precipitant and fragment to the micromesh on which crystallization will occur. This strict control of the specimen environment means that the crystallography experiments remain identical as the working volumes are decreased from the few microlitres level to the few nanolitres level. Using this system, lysozyme, thermolysin, trypsin and stachydrine demethylase crystals were co-crystallized with a small 33-compound mini-library to search for fragment hits. This technology pushes towards a much faster, more automated and more flexible strategy for structure-based drug discovery using as little as 2.5 nl of each major component.
Rabeprazole has been demonstrated to be a potent antisecretory agent and has been shown to be clinically effective in the treatment of acid-related diseases.
It was to determine the efficacy of ...rabeprazole at 20 and 40 mg in addition to amoxicillin and clarithromycin in the treatment of active Helicobacter pylori-positive duodenal ulcers compared with omeprazole 40 mg.
One hundred and twenty-seven patients were randomised into three treatment groups: 40 patients were treated with rabeprazole 40 mg daily, 42 patients with rabeprazole 20 mg daily and 45 patients with omeprazole 40 mg daily for 10 days. All patients received amoxicillin 1 g twice a day and clarithromycin 500 mg twice a day for 5 days. All patients were re-assessed at least 4 weeks after the end of the treatment.
According to the intention-to-treat (ITT) protocol, ulcer healing was observed in 90% of patients in the rabeprazole 40 group, in 85.7% in the rabeprazole 20 group and in 93.3% in the omeprazole 40 group. We observed H. pylori eradication in 90% ITT in the rabeprazole 40 group, in 80.9% ITT in the rabeprazole 20 group and in 88.8% ITT in the omeprazole 40 group. Statistical analysis did not show significant differences among the three groups.
A 10-day rabeprazole 20 mg regimen represents an efficacious and safe regimen for H. pylori eradication and ulcer healing.
