Direct and indirect high-performance liquid chromatographic enantioseparation of beta-amino acids.

Direct and indirect reversed-phase (RP) high-performance liquid chromatographic methods were developed for the separation of enantiomers of 18 unnatural beta-amino acids, including several beta-3-homo amino acids. The direct separations of the underivatized analytes were performed on chiral stationary phases (CSPs) containing macrocyclic glycopeptide antibiotic teicoplanin (Chirobiotic T column) and teicoplanin aglycone (Chirobiotic TAG column). The indirect method involved pre-column derivatization with a new chiral derivatizing agent (CDA), (S)-N-(4-nitrophenoxycarbonyl)phenylalanine methoxyethyl ester ((S)-NIFE), and subsequent separation of diastereomers on Discovery C18 and Hyperpep 300 C18 columns.

Comparison of the separation efficiencies of chirobiotic T and TAG columns in the separation of unusual amino acids.

Two macrocyclic antibiotic type chiral stationary phases (CSPs), based on native teicoplanin and teicoplanin aglycone, Chirobiotic T and Chirobiotic TAG, respectively, were evaluated for the high-performance liquid chromatographic separation of enantiomers of 15 unnatural conformationally constrained alpha-amino acids, Phe and Tyr analogs, and 12 beta-amino acids having cycloalkane or cycloalkene skeletons. The chromatographic results are given as the retention, separation and resolution factors along with the enantioselective free energy difference corresponding to the separation of the enantiomers. It is clearly established that in most cases the aglycone is responsible for the enantioseparation of amino acids.

Correlation of TIMI risk score with angiographic severity and extent of coronary artery disease in patients with non-ST-elevation acute coronary syndromes.

The Thrombolysis In Myocardial Infarction (TIMI) risk score predicts adverse clinical outcomes in patients with non-ST-elevation acute coronary syndromes (NSTEACS). Whether this score correlates with the coronary anatomy is unknown. We sought to determine whether the TIMI risk score correlates with the angiographic extent and severity of coronary artery disease (CAD) in patients with NSTEACS undergoing cardiac catheterization.

[Two years of mortality and morbidity conferences in a hospital gastrointestinal endoscopy unit].

Unlabelled: Mortality and morbidity conferences (M & MC) are designed to establish a collegial analysis of all complications in order to define their cause, assess avoidability and propose corrective measures aimed at preventing recurrence of the same kind of complications.

Aim: The aim of this study was to report the results of a quality improvement program focused on the complications of gastrointestinal endoscopy in a hospital endoscopy unit.

Methods: From 1/7/1999 to 30/6/2001, the complications of gastrointestinal endoscopic procedures were systematically and prospectively recorded and then retrospectively analysed during monthly M & MC.

Thoracic vein ablation terminates chronic atrial fibrillation in dogs.

The thoracic vein hypothesis of chronic atrial fibrillation (AF) posits that rapid, repetitive activations from muscle sleeves within thoracic veins underlie the mechanism of sustained AF. If this is so, thoracic vein ablation should terminate sustained AF and prevent its reinduction. Six female mongrel dogs underwent chronic pulmonary vein (PV) pacing at 20 Hz to induce sustained (>48 h) AF.

Structure-activity study on the Phe side chain arrangement of endomorphins using conformationally constrained analogues.

Endomorphins-1 and -2 were substituted with all the beta-MePhe stereoisomers in their Phe residues to generate a conformationally constrained peptide set. This series of molecules was subjected to biological assays, and for beta-MePhe(4)-endomorphins-2, a conformational analysis was performed. Incorporation of (2S,3S)-beta-MePhe(4) resulted in the most potent analogues of both endomorphins with enhanced enzymatic stability.

Liquid chromatographic enantioseparation of spin-labelled beta-amino acids.

Direct and indirect high-performance liquid chromatographic (HPLC) methods were developed for the enantioseparation of spin-labelled, cyclic, chiral beta-amino acids containing nitroxide free radicals, trans-3-amino- 1-oxyl-2,2,5,5-tetramethylpyrrolidine-4-carboxylic acid (trans-POAC), cis-4-amino-1-oxyl-2,2,6,6-tetramethylpiperidine-3-carboxylic acid (cis-beta-TOAC) and their N-Fmoc-protected analogues, synthesized in racemic and enantiomerically pure forms. The direct method involved the use of a Chiralcel OD-RH column, while indirect separation was carried out by application of either 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate or (S)-N-(4-nitrophenoxycarbonyl)-phenylalanine methoxyethyl ester as chiral derivatizing agent. Use of 1-fluoro-2,4-dinitrophenyl-5-L-alanine amide (Marfey's reagent) as chiral derivatizing agent failed because of the low of yield of the derivatization reaction.

Arrhythmogenic right ventricular dysplasia in the elderly.

Arrhythmogenic right ventricular dysplasia (ARVD) is a form of cardiomyopathy characterized by fibrofatty infiltration of the right ventricle that leads to cardiac arrhythmias, usually sustained ventricular tachycardia or ventricular fibrillation. ARVD typically becomes recognized in young adults. The authors report a case of an octogenarian in whom third-degree atrioventricular block, low cardiac output syndrome, and failure to capture the pacer stimuli developed.

Combined biological and chemical assessment of estrogenic activities in wastewater treatment plant effluents.

Five wastewater treatment plant effluents were analyzed for known endocrine disrupters and estrogenicity. Estrogenicity was determined by using the yeast estrogen screen (YES) and by measuring the blood plasma vitellogenin (VTG) concentrations in exposed male rainbow trout (Oncorhynchus mykiss). While all wastewater treatment plant effluents contained measurable concentrations of estrogens and gave a positive response with the YES, only at two sites did the male fish have significantly increased VTG blood plasma concentrations after the exposure, compared to pre-exposure concentrations.

Influence of obesity on lymph node recovery from rectal resection specimens.

Careful lymph node dissection from colorectal resection specimens is important procedure for cancer staging. Present study intended to assess the impact of surgical technique and patient's obesity on this process. Number of lymph nodes harvested by manual dissection from resection specimens of 141 patients with rectal cancer and the rate of nodal metastases were analyzed and compared in different groups of patients selected by length of resection specimen and body mass index.

Spatiotemporal correlation between phase singularities and wavebreaks during ventricular fibrillation.

Unlabelled: Phase Singularity and Wavebreak.

Introduction: Phase maps and the detection of phase singularities (PSs) have become a well-developed method for characterizing the organization of ventricular fibrillation (VF). How precisely PS colocalizes with wavebreak (WB) during VF, however, is unknown.

Free radical scavengers improve the impaired endothelium-dependent responses in aorta and kidneys of diabetic rabbits.

The effects of two endogenous antioxidants, alpha-lipoic acid and reduced gluthathione (GSH), were evaluated in the response of the renal vasculature and aortic rings ex vivo of 4-week alloxan-diabetic rabbits to the endothelium-dependent agonists bradykinin (BK) and acetylcholine (Ach) or to the endothelium-independent agonist sodium nitroprusside (SNP) and compared with age and sex-matched euglycemic rabbits. The maximal decrease in perfusion pressure (R(max)) after BK infusion in the renal vasculature from diabetic rabbits was 5.4+/-1.

Stress status of gudgeon (Gobio gobio) from rivers in Switzerland with and without input of sewage treatment plant effluent.

To assess the importance of sewage treatment plant effluents on fish health, we studied gudgeon in two rivers in the Swiss midlands (Canton Lucerne). Both rivers receive pollution from diffuse sources, while one also receives the effluent of a sewage treatment plant. Male and female gudgeon during and outside of the spawning season were compared with respect to reproductive parameters and health status across both rivers as well as upstream and downstream of the STP.

Application of a new chiral derivatizing agent to the enantioseparation of secondary amino acids.

A new chiral derivatizing agent, (S)-N-(4-nitrophenoxycarbonyl)phenylalanine methoxyethyl ester, (S)-NIFE, was applied for the high-performance liquid chromatographic separation of enantiomers of 19 unnatural secondary amino acids: proline, pipecolic acid analogues, piperazine-2-carboxylic acid, morpholine-3-carboxylic acid, thiomorpholine-3-carboxylic acid and analogues containing the 1,2,3,4-tetrahydroisoquinoline, 1,2,3,4-tetrahydronorharmane, 1,2,3,4-tetrahydro-2-carboline and 2-benzazepine skeletons. Excellent resolutions were achieved for most of the investigated compounds by using a reversed-phase mobile phase system. The conditions of separation were optimized by variation of the mobile phase composition.

Indirect molecular diagnosis of copper toxicosis in Bedlington terriers is complicated by haplotype diversity.

Positional cloning recently identified the mutation causing copper toxicosis (CT) in Bedlington terriers. Isolation of the MURR1 gene will be of great value in developing a reliable diagnostic test for the breeding of a copper toxicosis-free stock. It will replace the current diagnostic test using the CT-linked marker, C04107, which is located in intron 1 of the MURR1 gene with a distance of approximately 8 kb from the exon 2 deletion.

MBD1, MBD2 and CGBP genes at chromosome 18q21 are infrequently mutated in human colon and lung cancers.

The genes MBD1 and MBD2 encode methyl-CpG binding proteins that suppress transcription from methylated promoters. In contrast, CGBP encodes a protein that binds promoters containing unmethylated CpG and stimulates transcription. All three are located on human chromosome 18q21, a region of frequent loss of heterozygosity in several cancers.

Apoptosis of granulosa cells: a review on the role of MAPK-signalling modules.

Recent studies suggest that ovarian follicular atresia is associated with DNA fragmentation and degeneration of granulosa cells, the hallmark of programmed cell death or apoptosis. Apoptosis of granulosa cells play a major role in follicular atresia. These studies have also demonstrated the involvement of tumour suppressors, apoptotic proteins and survival factors.

Clinical impact of drug-eluting stents in changing referral practices for coronary surgical revascularization in a tertiary care center.

Background: The long-term benefits of angioplasty are limited by the occurrence of restenosis. Drug-eluting stents with a projected restenosis rate of close to 0% are soon to become available. The short- and long-term consequences of this advance to the cardiac surgical volume remain unclear.

Stress inhibits hair growth in mice by induction of premature catagen development and deleterious perifollicular inflammatory events via neuropeptide substance P-dependent pathways.

It has been much disputed whether or not stress can cause hair loss (telogen effluvium) in a clinically relevant manner. Despite the paramount psychosocial importance of hair in human society, this central, yet enigmatic and controversial problem of clinically applied stress research has not been systematically studied in appropriate animal models. We now show that psychoemotional stress indeed alters actual hair follicle (HF) cycling in vivo, ie, prematurely terminates the normal duration of active hair growth (anagen) in mice.

Proliferation and death of conditionally immortalized neural cells from murine neocortex: p53 alters the ability of neuron-like cells to re-enter the cell cycle.

Neurons are distinctive in that they are generally considered to be permanently post-mitotic cells. The oncoprotein p53 is a key regulator in neuronal development, notably in cell proliferation and neuronal death. We hypothesize that p53 maintains the post-mitotic characteristic of differentiated neurons.

Body fat mass in normal weight subjects.

Obesity is characterized by excessive body fat accumulation which may lead to serious health problems and complications. Body mass index is the most optimal parameter to evaluate the level of nutritional status and diagnose obesity. However, modern techniques studying body composition can more accurately determine whether the gain of body weight was on the account of body fat, lean body mass or total body water.

Efficacy of the anticaspase agent zVAD-fmk on post-thaw viability of canine spermatozoa.

Cryopreservation protocols for gametes are constantly improved with the aim of increasing the post-thaw viability of gametes. It is becoming clear that stress, resulting from cryopreservation, reduces cell numbers by apoptosis. Apoptosis, or programmed cell death, is a gene-activated event that occurs as a normal consequence of development and as a result of cellular stress.

[Charcot's joint as a chronic complication in diabetes mellitus].

Introduction: Charcot joints are considered to be chronic complications of diabetes mellitus. Although it is not a common disease, due to its progressive character, it can lead to permanent immobility and reduces quality of life in these patients. It is known that evolution of Charcot joints has three stages and the best results of therapy can only be achieved in the first stage.

[Informed consent for gastrointestinal endoscopy. A patient-opinion survey].

Aim: Written consent is not advised in France because it is thought it may alter the patient's trust in his/her doctor. Our aim was to elaborate a consent form for gastrointestinal endoscopy and to assess the patient's opinion concerning the written consent process.

Methods: Seven health professionals and seven patients or users elaborated a consent form and a list of 24 questions about the written consent process.