Spectroscopy of element 115 decay chains.

A high-resolution α, x-ray, and γ-ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum für Schwerionenforschung. Thirty correlated α-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z=115. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z>112. Comprehensive Monte Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.

Closure of defects of the atrial septum in adults using the Amplatzer device: 100 consecutive patients in a single center.

BACKGROUND: Transcatheter device closure of atrial septal defects (ASD) is an alternative to surgery, but experience is limited in adults, especially in those with large (> 26 mm) defects. HYPOTHESIS: We investigated the safety, efficacy, and learning curve for closure of ASD and patent foramen ovale (PFO) using the Amplatzer device. METHODS: In all, 101 procedures were carried out in 100 consecutive adult patients in a single cardiac center between July 1998 and August 2002. RESULTS: Preprocedure diagnosis was ASD and PFO in 50 patients each. A device was deployed in 94 of 101 attempts (93%) in 94 of 100 patients (94%). Atrial septal defect device sizes were 10-38 mm, median 24 mm, and 40% were > 26 mm. Major complications occurred in 2 of 100 patients (2%). One ASD device displaced requiring surgery within 24 h and one patient with PFO experienced pericardial tamponade; there were no deaths. Local vascular complications occurred in 4 of 100 (4%) and late complications in 4 of 100 (4%) patients. Patent foramen ovale closure was quicker (p<0.001), required less radiation (p=0.04), and was associated with fewer local vascular complications than ASD closure (p=0.04). Deployment of ASD devices > 26 mm was not associated with increased complications, length of procedure, or radiation compared with devices < or = 26 mm (all p>0.05). Complications in the first 35 patients were more frequent than in subsequent patients: 7 of 35 (20%) versus 3 of 65 (4.6%) (p=0.04); procedure and fluoroscopy times (both p<0.001) and radiation doses (p=0.001) were also higher. CONCLUSION: The Amplatzer device is an effective method for transcatheter closure of interatrial defects in adults, including large ASDs up to 38 mm. Major complications are uncommon. A learning curve of approximately 35 cases was suggested by the decline of complications, procedure times, and radiation exposure.

Afghanistan and the development of alternative systems of animal health in the absence of effective government.

This case study describes the efforts by both non-governmental organisations and United Nations agencies to develop an alternative system for delivering animal health services in Afghanistan, during a period in which there was effectively no government. The authors examine the period from the mid-1980s to the year 2003. During this time, Afghanistan experienced war and severe civil unrest, resulting in the collapse of the veterinary infrastructure. As most trained animal health professionals had fled the country, an initial emphasis was placed on training intermediate and lower-level veterinary auxiliary personnel, as well as on the implementation of emergency treatment and vaccination campaigns. Gradually this programme has developed from an emergency-oriented approach to a more development-oriented process, resulting in a community-based system of animal health care in more than 250 districts (out of approximately 360). Some 500 paraveterinarians, trained for a period of five months, play a pivotal role in this programme, supported in outlying villages by trained vaccinators and basic veterinary workers. In this paper, the authors present an estimation of the impact of this programme. Essential elements of the programme are, as follows: the recruitment of trainees from areas where need has been identified; an emphasis on practical and problem-oriented training; the deployment of staff in so-called 'veterinary field units', supervised by more highly qualified staff and monitors; a guaranteed supply of veterinary medicines, anthelmintics and vaccines; a gradually increasing rate of cost recovery. The ultimate objective of the programme is to establish a self-sustaining system, based on the 'user-pays' principle. The paper concludes by describing the present-day problems of the animal health infrastructure in Afghanistan. Not only must the new government try to regain its central position, it must also assimilate two decades of development in the veterinary sector, which has occurred largely outside governmental control.

Transformation of the host-selective toxin destruxin B by wild crucifers: probing a detoxification pathway.

The destruxin B detoxification pathway present in Sinapis alba is also present in three unrelated species, Camelina sativa, Capsella bursa-pastoris, and Eruca sativa, suggesting a conservation of this pathway across crucifers. The chemical structure of a destruxin B metabolite, (6'-O-malonyl)hydroxydestruxin B beta-D-glucopyranoside, was also establised. Considering that Camelina sativa and Capsella bursa-pastoris detoxify destruxin B and produce the phytoalexins camalexins, these wild crucifers appear to represent unique and perhaps useful sources of blackleg resistance in strategic plant breeding.

Syn-anti isomerization of aldols by enolization.

[reaction--see text] A variety of aldol adducts (i.e., 3-hydroxy ketones) are shown to undergo syn-anti isomerization in the presence of imidazole by an enolization mechanism with negligible retroaldol or elimination products.

Probing host-selective phytotoxicity: synthesis of destruxin B and several natural analogues.

The syntheses of the host-selective phytotoxin destruxin B [cyclo(betaAla-Hmp-Pro-Ile-MeVal-MeAla), Hmp = (2R)-2-hydroxy-4-methylpentanoic acid], and the closely related natural analogues homodestruxin B (MeVal-->MeIle), desmethyldestruxin B (MeVal-->Val), hydroxydestruxin B (Hmp-->Dhmp, Dhmp = (2R)-2,4-dihydroxy-4-methylpentanoic acid), and hydroxyhomodestruxin B (MeVal-->MeIle, Hmp-->Dhmp) are described. In each case, the MeAla-betaAla linkage was formed by cyclization and the precursor linear hexadepsipeptides were formed by condensing two three-residue fragments. Radiolabeled samples of destruxin B, homodestruxin B, and hydroxydestruxin B were prepared by coupling [3-(14)C]-beta-alanine to the appropriate pentadepsipeptide followed by cyclization. A noteworthy feature of the synthesis involves the novel use of a Boc-hydrazide protecting group on dipeptides with a C-terminal N-methylalanine residue to inhibit the otherwise facile dioxopiperazine formation during peptide coupling.

The NADH oxidase from Pyrococcus furiosus. Implications for the protection of anaerobic hyperthermophiles against oxidative stress.

A wealth of H(2)O-producing NADH oxidase (NOX) homologues have been discovered in the genomes of the hyperthermophilic Archaea, including two homologues in the genome of Pyrococcus furiosus which have been designated as NOX1 and NOX2. In order to investigate the function of NOX1, the structural gene encoding NOX1 was cloned from the genome of P. furiosus and expressed in Escherichia coli, and the resulting recombinant enzyme (rNOX1) was purified to homogeneity. The enzyme is a thermostable flavoprotein that can be reconstituted only with FAD. rNOX1 catalyzes the oxidation of NADH, producing both H(2)O(2) and H(2)O as reduction products of O(2) (O(2) + 1-2NADH + 1-2H(+) --> 1-2NAD(+) + H(2)O(2) or 2H(2)O). To our knowledge, this is the first NADH oxidase found to produce both H(2)O(2) and H(2)O. The enzyme exhibits a low K(m) for NADH (< 4 microm), and shows little or no reaction with NADPH. Transcriptional analyses demonstrated that NOX1 is constitutively expressed regardless of the carbon source and a single promoter was identified 25 bp upstream of the nox1 gene by primer extension. Although P. furiosus is a strict anaerobe, it may tolerate oxygen to some extent and we anticipate NOX1 to be involved in the response to oxygen at high temperatures.

The phosphoglucose isomerase from the hyperthermophilic archaeon Pyrococcus furiosus is a unique glycolytic enzyme that belongs to the cupin superfamily.

Pyrococcus furiosus uses a variant of the Embden-Meyerhof pathway during growth on sugars. All but one of the genes that encode the glycolytic enzymes of P. furiosus have previously been identified, either by homology searching of its genome or by reversed genetics. We here report the isolation of the missing link of the pyrococcal glycolysis, the phosphoglucose isomerase (PGI), which was purified to homogeneity from P. furiosus and biochemically characterized. The P. furiosus PGI, a dimer of identical 23.5-kDa subunits, catalyzes the reversible isomerization of glucose 6-phosphate to fructose 6-phosphate, with K(m) values of 1.99 and 0.63 mm, respectively. An optimum pH of 7.0 has been determined in both directions, and at its optimum temperature of 90 degrees C the enzyme has a half-life of 2.4 h. The N-terminal sequence was used for the identification of the pgiA gene in the P. furiosus genome. The pgiA transcription start site has been determined, and a monocistronic messenger was detected in P. furiosus during growth on maltose and pyruvate. The pgiA gene was functionally expressed in Escherichia coli BL21(DE3). The deduced amino acid sequence of this first archaeal PGI revealed that it is not related to its bacterial and eukaryal counterparts. In contrast, this archaeal PGI shares similarity with the cupin superfamily that consists of a variety of proteins that are generally involved in sugar metabolism in both prokaryotes and eukaryotes. As for the P. furiosus PGI, distinct phylogenetic origins have previously been reported for other enzymes from the pyrococcal glycolytic pathway. Apparently, convergent evolution by recruitment of several unique enzymes has resulted in the unique Pyrococcus glycolysis.

Symptomatic improvement after radiofrequency catheter ablation for typical atrial flutter.

OBJECTIVE: To assess the changes in quality of life, arrhythmia symptoms, and hospital resource utilisation following catheter ablation of typical atrial flutter. DESIGN: Patient questionnaire to compare the time interval following ablation with a similar time interval before ablation. SETTING: Tertiary referral centre. PATIENTS: 63 consecutive patients were studied. Four patients subsequently underwent an ablate and pace procedure, two died of co-morbid illnesses, and two were lost to follow up. The remaining 55 patients form the basis of the report. RESULTS: Patients were followed for a mean (SD) of 12 (9.5) months. Atrial flutter ablation resulted in an improvement in quality of life (3.8 v 2.5, p < 0.001) and reductions in symptom frequency score (2.0 v 3.5, p < 0.001) and symptom severity score (2.0 v 3.8, p < 0.001) compared with preablation values. There was a reduction in the number of patients visiting accident and emergency departments (11% v 53%, p < 0.001), requiring cardioversion (7% v 51%, p < 0.001), or being admitted to hospital for a rhythm problem (11% v 56%, p < 0.001). Subgroup analysis confirmed that patients with atrial flutter and concomitant atrial fibrillation before ablation and those with atrial flutter alone both derived significant benefit from atrial flutter ablation. Patients with concomitant atrial fibrillation had an improvement in quality of life (3.5 v 2.5, p < 0.001) and reductions in symptom frequency score (2.3 v 3.5, p < 0.001) and symptom severity score (2.2 v 3.7, p < 0.001) compared with preablation values. CONCLUSIONS: Ablation of atrial flutter is recommended both in patients with atrial flutter alone and in those with concomitant atrial fibrillation.

Smoke from wildland fires

It discusses the effects of some products of combustion on health and on the air quality, and presents information on the ratios of toxic air pollutants to CO, CH4 and PM2.5. Document in pdf format; Acrobat Reader required.

In planta sequential hydroxylation and glycosylation of a fungal phytotoxin: Avoiding cell death and overcoming the fungal invader.

To facilitate plant colonization, some pathogenic fungi produce phytotoxic metabolites that damage tissues; plants may be resistant to a particular pathogen if they produce an enzyme(s) that catalyzes detoxification of this metabolite(s). Alternaria blackspot is one of the most damaging and significant fungal diseases of brassica crops, with no source of resistance known within the Brassica species. Destruxin B is the major phytotoxin produced by the blackspot-causing fungus, Alternaria brassicae (Berkley) Saccardo. We have established that a blackspot-resistant species (Sinapis alba) metabolized (14)C-labeled destruxin B to a less toxic product substantially faster than any of the susceptible species. The first metabolite, hydroxydestruxin B ((14)C-labeled), was further biotransformed to the beta-d-glucosyl derivative at a slower rate. The structures of hydroxydestruxin B and beta-d-glucosyl hydroxydestruxin B were deduced from their spectroscopic data [NMR, high resolution (HR)-MS, Fourier transform infrared (FTIR)] and confirmed by total chemical synthesis. Although these hydroxylation and glucosylation reactions occurred in both resistant (S. alba) and susceptible (Brassica napus, Brassica juncea, and Brassica rapa) species, hydroxylation was the rate limiting step in the susceptible species, whereas glucosylation was the rate limiting step in the resistant species. Remarkably, it was observed that the hydroxydestruxin B induced the biosynthesis of phytoalexins in blackspot-resistant species but not in susceptible species. This appears to be a unique example of phytotoxin detoxification and simultaneous phytoalexin elicitation by the detoxification product. Our studies suggest that S. alba can overcome the fungal invader through detoxification of destruxin B coupled with production of phytoalexins.

Endothelial dysfunction, subangiographic atheroma, and unstable symptoms in patients with chest pain and normal coronary arteriograms.

BACKGROUND: Patients with chest pain and normal coronary arteriograms (CPNA) may present with unstable symptoms and other evidence of ischemia during clinical follow-up. Although repeat angiography usually proves negative, functional assessment of coronary vasomotor abnormalities may provide additional pathophysiologic information. HYPOTHESIS: The study was undertaken to evaluate the relationship between endothelial dysfunction and subangiographic atheroma in patients with CPNA undergoing repeat angiography because of unstable symptoms. METHODS: We investigated nine patients with CPNA (8 women, mean age 57 +/- 9 years) undergoing repeat angiography because of unstable anginal symptoms. After normal angiography, simultaneous coronary epicardial and microvascular vasomotor responses to intracoronary vasodilators [acetylcholine (10(-6) M), adenosine (18 micrograms) and nitroglycerin (300 micrograms)] were investigated in the left anterior descending artery using quantitative angiography and Doppler flow measurements. The presence of subangiographic atheroma was assessed by intravascular ultrasound. RESULTS: Three patients demonstrated proximal and distal epicardial vasoconstriction and a reduction in coronary flow in response to acetylcholine, indicating concordant epicardial and microvascular endothelial dysfunction. These changes were associated with chest pain and ischemic electrocardiographic changes in two patients. None of the remaining patients suffered chest pain in response to intracoronary acetylcholine. Six patients had significant subangiographic disease (intimal thickness > 0.3 mm) on intravascular ultrasound imaging, and multivariate analysis indicated a significant relationship (R2 = 0.89, overall p = 0.001) between the extent of subangiographic disease and both plasma cholesterol concentration and hypertensive history. No significant relationship was demonstrated between endothelial dysfunction and the extent of subangiographic disease. CONCLUSION: Concordant epicardial and microvascular endothelial dysfunction may be pathophysiologically and clinically significant in unstable patients with CPNA but does not appear to be directly related to the extent of subangiographic atheroma.

A general approach to cyathin diterpenes. Total synthesis of allocyathin B(3).

[reaction: see text] The synthesis of allocyathin B(3) from an advanced intermediate possessing the ring system and relative stereochemistry but lacking the isopropyl and hydroxymethyl groups is reported. The isopropyl group was introduced by radical cyclization of a methyl propargyl acetal of an alpha-bromo ketone, and the hydroxymethyl group was generated by Pd-catalyzed carbonylation of a vinyl triflate. The route provides functionalized intermediates that could allow access to more complex members of the cyathin family of diterpenes.

Branched-chain alpha-keto acid catabolism via the gene products of the bkd operon in Enterococcus faecalis: a new, secreted metabolite serving as a temporary redox sink.

Recently the bkd gene cluster from Enterococcus faecalis was sequenced, and it was shown that the gene products constitute a pathway for the catabolism of branched-chain alpha-keto acids. We have now investigated the regulation and physiological role of this pathway. Primer extension analysis identified the presence of a single promoter upstream of the bkd gene cluster. Furthermore, a putative catabolite-responsive element was identified in the promoter region, indicative of catabolite repression. Consistent with this was the observation that expression of the bkd gene cluster is repressed in the presence of glucose, fructose, and lactose. It is proposed that the conversion of the branched-chain alpha-keto acids to the corresponding free acids results in the formation of ATP via substrate level phosphorylation. The utilization of the alpha-keto acids resulted in a marked increase of biomass, equivalent to a net production of 0.5 mol of ATP per mol of alpha-keto acid metabolized. The pathway was active under aerobic as well as anaerobic conditions. However, under anaerobic conditions the presence of a suitable electron acceptor to regenerate NAD(+) from the NADH produced by the branched-chain alpha-keto acid dehydrogenase complex was required for complete conversion of alpha-ketoisocaproate. Interestingly, during the conversion of the branched-chain alpha-keto acids an intermediate was always detected extracellularly. With alpha-ketoisocaproic acid as the substrate this intermediate was tentatively identified as 1, 1-dihydroxy-4-methyl-2-pentanone. This reduced form of alpha-ketoisocaproic acid was found to serve as a temporary redox sink.

Purification and characterization of the alanine aminotransferase from the hyperthermophilic Archaeon pyrococcus furiosus and its role in alanine production.

Alanine aminotransferase (AlaAT) was purified from cell extracts of the hyperthermophilic archaeon Pyrococcus furiosus by multistep chromatography. The enzyme has an apparent molecular mass of 93.5 kDa, as estimated by gel filtration, and consists of two identical subunits of 46 kDa, as deduced by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the gene sequence. The AlaAT displayed a broader substrate specificity than AlaATs from eukaryal sources and exhibited significant activity with alanine, glutamate, and aspartate with either 2-oxoglutarate or pyruvate as the amino acceptor. Optimal activity was found in the pH range of 6. 5 to 7.8 and at a temperature of over 95 degrees C. The N-terminal amino acid sequence of the purified AlaAT was determined and enabled the identification of the gene encoding AlaAT (aat) in the P. furiosus genome database. The gene was expressed in Escherichia coli, and the recombinant enzyme was purified. The pH and temperature dependence, molecular mass, and kinetic parameters of the recombinant were indistinguishable from those of the native enzyme from P. furiosus. The k(cat)/K(m) values for alanine and pyruvate formation were 41 and 33 s(-1) mM(-1), respectively, suggesting that the enzyme is not biased toward either the formation of pyruvate, or alanine. Northern analysis identified a single 1.2-kb transcript for the aat gene. In addition, both the aat and gdh (encoding the glutamate dehydrogenase) transcripts appear to be coregulated at the transcriptional level, because the expression of both genes was induced when the cells were grown on pyruvate. The coordinated control found for the aat and gdh genes is in good agreement with these enzymes acting in a concerted manner to form an electron sink in P. furiosus.

Catabolism of branched-chain alpha-keto acids in Enterococcus faecalis: the bkd gene cluster, enzymes, and metabolic route.

Genes encoding a branched-chain alpha-keto acid dehydrogenase from Enterococcus faecalis 10C1, E1alpha (bkdA), E1beta (bkdB), E2 (bkdC), and E3 (bkdD), were found to reside in the gene cluster ptb-buk-bkdDABC. The predicted products of ptb and buk exhibited significant homology to the phosphotransbutyrylase and butyrate kinase, respectively, from Clostridium acetobutylicum. Activity and redox properties of the purified recombinant enzyme encoded by bkdD indicate that E. faecalis has a lipoamide dehydrogenase that is distinct from the lipoamide dehydrogenase associated with the pyruvate dehydrogenase complex. Specific activity of the ptb gene product expressed in Escherichia coli was highest with the substrates valeryl-coenzyme A (CoA), isovaleryl-CoA, and isobutyryl-CoA. In cultures, a stoichiometric conversion of alpha-ketoisocaproate to isovalerate was observed, with a concomitant increase in biomass. We propose that alpha-ketoisocaproate is converted via the BKDH complex to isovaleryl-CoA and subsequently converted into isovalerate via the combined actions of the ptb and buk gene products with the concomitant phosphorylation of ADP. In contrast, an E. faecalis bkd mutant constructed by disruption of the bkdA gene did not benefit from having alpha-ketoisocaproate in the growth medium, and conversion to isovalerate was less than 2% of the wild-type conversion. It is concluded that the bkd gene cluster encodes the enzymes that constitute a catabolic pathway for branched-chain alpha-keto acids that was previously unidentified in E. faecalis.

Double-blind placebo-controlled trial of digoxin in symptomatic paroxysmal atrial fibrillation.

BACKGROUND: Digoxin is commonly prescribed in symptomatic paroxysmal atrial fibrillation (AF) but has never been evaluated in this condition. METHODS AND RESULTS: From a multicenter registry, 43 representative patients with frequent symptomatic AF episodes were recruited into a randomized, double-blind crossover comparison of digoxin (serum concentration, 1.29+/-0.35 nmol/L) and placebo. The study end point was the occurrence of 2 AF episodes (documented by patient-activated monitors), censored at 61 days. The median time to 2 episodes was 13.5 days on placebo and 18.7 days on digoxin (P<0. 05). The relative risk (95% CI) of 2 episodes (placebo:digoxin) was 2.19 (1.07 to 4.50). A similar effect was seen on the median time to 1 episode: increased from 3.5 to 5.4 days (P<0.05), relative risk 1. 69 (0.88 to 3.24). The mean+/-SD ventricular rates during AF recordings during placebo and digoxin treatment were 138+/-32 and 125+/-35 bpm, respectively (P<0.01). Twenty-four-hour ambulatory ECG recordings did not show significant differences in the frequency or duration of AF or in ventricular rate. CONCLUSIONS: Digoxin reduces the frequency of symptomatic AF episodes. However, the estimated effect is small and may be due to a reduction in the ventricular rate or irregularity rather than an antiarrhythmic action.