The use of fluorescence correlation spectroscopy to monitor cell surface ß2-adrenoceptors at low expression levels in human embryonic stem cell-derived cardiomyocytes and fibroblasts.

The importance of cell phenotype in determining the molecular mechanisms underlying ß2 -adrenoceptor (ß2AR) function has been noted previously when comparing responses in primary cells and recombinant model cell lines. Here, we have generated haplotype-specific SNAP-tagged ß2AR human embryonic stem (ES) cell lines and applied fluorescence correlation spectroscopy (FCS) to study cell surface receptors in progenitor cells and in differentiated fibroblasts and cardiomyocytes. FCS was able to quantify SNAP-tagged ß2AR number and diffusion in both ES-derived cardiomyocytes and CRISPR/Cas9 genome-edited HEK293T cells, where the expression level was too low to detect using standard confocal microscopy. These studies demonstrate the power of FCS in investigating cell surface ß2ARs at the very low expression levels often seen in endogenously expressing cells. Furthermore, the use of ES cell technology in combination with FCS allowed us to demonstrate that cell surface ß2ARs internalize in response to formoterol-stimulation in ES progenitor cells but not following their differentiation into ES-derived fibroblasts. This indicates that the process of agonist-induced receptor internalization is strongly influenced by cell phenotype and this may have important implications for drug treatment with long-acting ß2AR agonists.

Antimicrobial resistance tendency and collateral sensitivity of Staphylococcus aureus adapted to antibiotics or extracts of medicinal plants grown in Viet Nam.

Antimicrobial resistance has silently turned into one of the biggest threats to global health, marking the fall of the Golden age of antibiotics. In the search for antibiotic replacement or enhancement, plant-derived natural compounds have attracted lots of interest. Even though firmly believed, the low-resistance tendency of pathogenic bacteria against plant extracts has been scarcely demonstrated. In this study, we investigated the antibacterial activities of diethyl ether extracts from six medicinal plants grown in Viet Nam against Staphylococcus aureus and its variants, which were in vitro adapted to the same extracts. After 30 passages of S. aureus growing under sub-lethal concentrations of plant extracts or antibiotics, the bacteria slowly adapted to the extracts while rapidly resisting the antibiotics. Most of the resulting strains obtained from the adaptation to plant extracts were collaterally sensitive to antibiotics. In contrast, antibiotic-adapted strains showed cross-resistance to both antibiotics and extracts. The findings provided evidence of the low-resistance tendency of S. aureus to antimicrobial plant extracts. It is the first time a collateral antibiotic sensitivity of S. aureus adapted to natural compounds has been observed, suggesting an alternative approach to fight antibiotic resistance.

Dietary soluble non-starch polysaccharide level and composition influences grower and finisher phase performance, excreta moisture content and total tract nutrient digestibility in broilers.

1. The aim of this study was to examine the impact of dietary soluble non-starch polysaccharide (sNSP) level and composition on grower and finisher phase performance, total tract nutrient digestibility and excreta moisture content in broiler chickens.2. Cobb 500 broilers (n = 1080) were fed 12 dietary treatments; four diets with differing primary grain sources (barley, corn, sorghum and wheat) and three different sNSP levels (low, medium and high). Diets were formulated to have similar protein and energy levels but differing sNSP levels, induced by manipulating the quantity of the ingredients in the diet. The diets were fed in three phases, starter (d 0-12), grower (d 12-23) and finisher (d 23-31).3. For birds aged d 23 and 31, total pen body weight and feed intake were determined, and fresh excreta and litter samples were collected per pen. Dry matter (DM) content was measured in the excreta and litter samples. Total tract DM digestibility, apparent metabolisable energy corrected to nitrogen (AMEn), and soluble and insoluble NSP and free oligosaccharide degradability were evaluated.4. In birds fed the sorghum- and corn-based diets, feeding high sNSP resulted in a lower cFCR at d 0-23 compared to low sNSP (P = 0.004 and P = 0.044, respectively). In birds fed the corn-based diet, feeding low sNSP resulted in the lowest litter DM but highest DM digestibility at d 23 (P = 0.045 and P < 0.001) and d 31 (P = 0.022 and P = 0.008). For all diets, degradability of sNSP was higher and insoluble NSP was lower when feeding low compared to high sNSP (P < 0.001). In birds fed the barley- and sorghum-based diets, AMEn was lower when feeding the low compared to high sNSP level (P < 0.001 and P = 0.016, respectively).6. Results from this study showed that level of dietary sNSP impacts broiler productive performance and nutrient utilisation.

Intensified Antituberculosis Therapy in Adults with Tuberculous Meningitis.

BACKGROUND: Tuberculous meningitis is often lethal. Early antituberculosis treatment and adjunctive treatment with glucocorticoids improve survival, but nearly one third of patients with the condition still die. We hypothesized that intensified antituberculosis treatment would enhance the killing of intracerebral Mycobacterium tuberculosis organisms and decrease the rate of death among patients. METHODS: We performed a randomized, double-blind, placebo-controlled trial involving human immunodeficiency virus (HIV)-infected adults and HIV-uninfected adults with a clinical diagnosis of tuberculous meningitis who were admitted to one of two Vietnamese hospitals. We compared a standard, 9-month antituberculosis regimen (which included 10 mg of rifampin per kilogram of body weight per day) with an intensified regimen that included higher-dose rifampin (15 mg per kilogram per day) and levofloxacin (20 mg per kilogram per day) for the first 8 weeks of treatment. The primary outcome was death by 9 months after randomization. RESULTS: A total of 817 patients (349 of whom were HIV-infected) were enrolled; 409 were randomly assigned to receive the standard regimen, and 408 were assigned to receive intensified treatment. During the 9 months of follow-up, 113 patients in the intensified-treatment group and 114 patients in the standard-treatment group died (hazard ratio, 0.94; 95% confidence interval, 0.73 to 1.22; P=0.66). There was no evidence of a significant differential effect of intensified treatment in the overall population or in any of the subgroups, with the possible exception of patients infected with isoniazid-resistant M. tuberculosis. There were also no significant differences in secondary outcomes between the treatment groups. The overall number of adverse events leading to treatment interruption did not differ significantly between the treatment groups (64 events in the standard-treatment group and 95 events in the intensified-treatment group, P=0.08). CONCLUSIONS: Intensified antituberculosis treatment was not associated with a higher rate of survival among patients with tuberculous meningitis than standard treatment. (Funded by the Wellcome Trust and the Li Ka Shing Foundation; Current Controlled Trials number, ISRCTN61649292.).

Correction to: Common findings of blaCTX-M-55-encoding 104-139 kbp plasmids harbored by extended-spectrum ß-lactamase-producing Escherichia coli in pork meat, wholesale market workers, and patients with urinary tract infection in Vietnam.

The original version of this article unfortunately contained a mistake. The legends of Tables 2 and 3, Fig. 1 are incorrect. The corrected legends are given below.

Progress towards rabies control and elimination in Vietnam.

Rabies is a fatal viral disease that causes an estimated 59,000 human deaths each year. The majority of these deaths occur in developing countries in Asia. Canine rabies is endemic to Vietnam, which is, however, moving towards the disease's elimination. Many countries, such as Vietnam, have invested tremendous resources in controlling rabies, highlighting the goal of regional and global elimination of this neglected disease. In Vietnam, rabies is recognised as one of five high-priority, zoonotic diseases by the Ministry of Health and the Ministry of Agriculture and Rural Development. Investment by the government and by international partners for rabies prevention and control has played a substantial role in reducing human rabies deaths from 404 cases in 1992 to 74 cases in 2017. The catalyst for this effort was the Prime Minister's creation of the National Rabies Program in 1996, which led to increased support and resources for rabies prevention and control. Interventions carried out since then include the expansion of post-exposure prophylaxis centres throughout the country, the introduction or revision of key legislation and guidelines, and improved multisectoral One Health collaboration. In addition, support from international partners, such as the World Organisation for Animal Health (OIE), the World Health Organization (WHO), the Food and Agriculture Organization of the United Nations (FAO), and the Centers for Disease Control and Prevention (CDC), has helped to increase awareness, manage dog populations more effectively, and improve Vietnam's surveillance and diagnostic capabilities. To pursue the goal of eliminating dog-mediated rabies in Vietnam, political commitment is crucial. Resources must be made available to enforce the regulations and guidelines that will enable Vietnam to achieve greater canine rabies vaccination coverage. In this paper, the authors provide an overview of the animal and human health systems in Vietnam, as well as past, current and future directions of rabies prevention and control.

La rage est une maladie virale à l'issue mortelle faisant chaque année un nombre estimé de 59 000 victimes humaines. La plupart de ces décès surviennent dans les pays en développement d'Asie. Au Vietnam, la rage canine est endémique mais le pays poursuit activement l'objectif d'éliminer la rage de son territoire. À l'instar du Vietnam, plusieurs pays ont investi des ressources colossales pour contrôler la rage, renforçant ainsi la dimension régionale et mondiale de l'objectif d'élimination de cette maladie négligée. Au Vietnam, la rage figure parmi les cinq zoonoses hautement prioritaires prises en compte par le ministère de la Santé et le ministère de l'Agriculture et du développement rural. Les investissements consacrés à la prévention et au contrôle de la rage par le gouvernement et ses partenaires internationaux ont joué un rôle déterminant dans la réduction du nombre de décès humains dus à la rage, qui est passé de 404 cas en 1992 à 74 cas en 2017. L'élément catalyseur de cet effort a été la création en 1996 du Programme national de lutte contre la rage par le premier ministre de l'époque, ce qui a permis de renforcer les ressources et le soutien dédiés à la prévention et à la lutte contre la rage. Depuis lors, les interventions ont porté sur la création de centres de prophylaxie post-exposition sur tout le territoire, l'introduction ou la révision de la législation et des lignes directrices applicables et l'amélioration de la collaboration Une seule santé. En outre, le soutien de partenaires internationaux tels que l'Organisation mondiale de la santé animale (OIE), l'Organisation mondiale de la santé (OMS), l'Organisation des Nations Unies pour l'alimentation et l'agriculture (FAO) et les Centres pour le contrôle et la prévention des maladies (CDC, États-Unis d'Amérique) a abouti à une meilleure sensibilisation, à une gestion plus efficace des populations de chiens et à un renforcement des capacités de surveillance et de diagnostic au Vietnam. Un engagement politique fort est indispensable pour réussir à éliminer totalement la rage transmise par les chiens au Vietnam. Des ressources doivent être rendues disponibles afin de mettre en oeuvre la réglementation et les lignes directrices pertinentes et d'augmenter ainsi la couverture vaccinale de la population canine du pays. Les auteurs décrivent les systèmes de santé animale et publique du Vietnam ainsi que les orientations passées, actuelles et futures de la prévention et du contrôle de la rage dans le pays.

La rabia es una enfermedad vírica fatal, que según las estimaciones mata a 59 000 personas al año, mayoritariamente en países en desarrollo asiáticos. La rabia canina es endémica en el Vietnam, país que no obstante avanza ahora hacia la eliminación de la enfermedad. Como el Vietnam, muchos países han invertido cantidades colosales de recursos en la lucha antirrábica, subrayando con ello su compromiso con el objetivo de eliminar esta enfermedad desatendida a escala regional y mundial. El Ministerio de Salud y el Ministerio de Agricultura y Desarrollo Rural del Vietnam tienen catalogada la rabia como una de las cinco enfermedades zoonóticas que revisten máxima prioridad. Las inversiones en prevención y control de la rabia realizadas por el gobierno y por asociados internacionales han ayudado sensiblemente a reducir el número de personas muertas por la rabia, que ha pasado de 404 casos en 1992 a 74 en 2017. El catalizador de este esfuerzo fue la creación en 1996, por iniciativa del Primer Ministro, del Programa Nacional contra la Rabia, que se tradujo en un aumento del apoyo y los recursos destinados a prevenir y combatir la enfermedad. Entre otras intervenciones, desde entonces se ha multiplicado en todo el país el número de centros donde se dispensa profilaxis tras la exposición, se han promulgado o revisado leyes, decretos y directrices fundamentales y se ha mejorado la colaboración multisectorial en clave de Una sola salud. Además, el respaldo de asociados internacionales como la Organización Mundial de Sanidad Animal (OIE), la Organización Mundial de la Salud (OMS), la Organización de las Naciones Unidas para la Alimentación y la Agricultura (FAO) o los Centros para el Control y la Prevención de Enfermedades (CDC) de los Estados Unidos ha ayudado a generar una mayor conciencia del problema, a gestionar más eficazmente las poblaciones de perros y a dotar al país de mejores medios de vigilancia y diagnóstico. Para hacer realidad el objetivo de eliminar del Vietnam la rabia transmitida por perros, la voluntad política es un factor clave, pues hay que poner sobre la mesa los recursos necesarios para aplicar los reglamentos y normas que permitirán al país ampliar la cobertura de vacunación canina antirrábica. Tras trazar una panorámica de los sistemas sanitario y zoosanitario del Vietnam, los autores describen el rumbo pasado, presente y futuro de las labores de prevención y control de la rabia en el país.

Encapsulation of Neurotoxins, Blockers of Nicotinic Acetylcholine Receptors, in Nanomaterials Based on Sulfated Polysaccharides.

Three-finger snake neurotoxins are selective antagonists of some nicotinic acetylcholine receptor subtypes and are widely used to study these receptors. The peptide neurotoxin azemiopsin, recently isolated from the venom of Azemipos feae, is a selective blocker of muscle-type nicotinic acetylcholine receptor. In order to reduce their toxicity and increase resistance under physiological conditions, we have encapsulated these toxins into nanomaterials. The study of nanomaterials after interaction with neurotoxins by the methods of transmission electron microscopy and dynamic light scattering revealed an increase in the size of nanoparticles, which indicates the inclusion of neurotoxins in nanomaterials.

Direct Observation of Zhang-Li Torque Expansion of Magnetic Droplet Solitons.

Magnetic droplets are nontopological dynamical solitons that can be nucleated in nanocontact based spin torque nano-oscillators (STNOs) with perpendicular magnetic anisotropy free layers. While theory predicts that the droplet should be of the same size as the nanocontact, its inherent drift instability has thwarted attempts at observing it directly using microscopy techniques. Here, we demonstrate highly stable magnetic droplets in all-perpendicular STNOs and present the first detailed droplet images using scanning transmission X-ray microscopy. In contrast to theoretical predictions, we find that the droplet diameter is about twice as large as the nanocontact. By extending the original droplet theory to properly account for the lateral current spread underneath the nanocontact, we show that the large discrepancy primarily arises from current-in-plane Zhang-Li torque adding an outward pressure on the droplet perimeter. Electrical measurements on droplets nucleated using a reversed current in the antiparallel state corroborate this picture.

Association of a functional TNF variant with Plasmodium falciparum parasitaemia in a congolese population.

Several studies have provided evidence of both helpful and harmful effects of TNF on the outcome of Plasmodium falciparum malaria infection. Several TNF polymorphisms that are located within non-coding regions have been associated with parasitaemia, mild malaria or severe malaria. We investigated the association of TNF1304 (rs3093664), TNF-308 (rs1800629), TNF-238 (rs361525) and TNF-244 (rs673) with mild malaria and symptomatic maximum parasitaemia in a population-based design (n=310). We obtained nominal evidence for an association between symptomatic maximum parasitaemia and TNF-308, TNF-238, and TNF-244 on the one hand, and between the number of mild malaria attacks and TNF-244 on the other hand. After accounting for multiple tests, we confirmed the association of symptomatic maximum parasitaemia with TNF-244. We further provide bioinformatics and experimental evidence that TNF-244 has a cis-regulatory effect. This is the first report that emphasizes the potential role of TNF-244 in malaria.

Common findings of bla CTX-M-55-encoding 104-139 kbp plasmids harbored by extended-spectrum ß-lactamase-producing Escherichia coli in pork meat, wholesale market workers, and patients with urinary tract infection in Vietnam.

Extended-spectrum, ß-lactamase-producing Escherichia coli (ESBL-E) harboring the bla CTX-M-55-encoding plasmid (ESBL-E55) has been reported to be associated with urinary tract infection (UTI). The aims of this study were to clarify the prevalence of ESBL-E55 in pork meats and workers from the same wholesale market, as well as patients with UTI from a nearby hospital in Vietnam; we also investigated the plasmids encoding bla CTX-M-55. Sequencing analysis showed that 66.6% of the ESBL-E isolated from pork meats contained bla CTX-M-55, whereas the gene was present in 25.0% of workers and 12.5% of patients with UTI. Plasmid analysis showed that several sizes of plasmid encoded bla CTX-M-55 in ESBL-E55 isolated from pork meats, whereas ESBL-E55 isolated from workers and patients with UTI contained only 104-139 kbp of bla CTX-M-55-encoding plasmids. This indicates that the 104-139 kbp sizes of bla CTX-M-55-encoding plasmids were commonly disseminated in pork meats, wholesale market workers, and patients with UTI.

What is the mechanism of Ketamine's rapid-onset antidepressant effect? A concise overview of the surprisingly large number of possibilities.

WHAT IS KNOWN AND OBJECTIVE: Abundant clinical data now confirm that ketamine produces a remarkable rapid-onset antidepressant effect - hours or days - in contrast to the delayed onset (typically weeks) of current antidepressant drugs. This surprising and revolutionary finding may lead to the development of life-saving pharmacotherapy for depressive illness by reducing the high suicide risk associated with the delayed onset of effect of current drugs. As ketamine has serious self-limiting drawbacks that restrict its widespread use for this purpose, a safer alternative is needed. Our objective is to review the proposed mechanism(s) of ketamine's rapid-onset antidepressant action for new insights into the physiological basis of depressive illness that may lead to new and novel targets for antidepressant drug discovery. METHODS: A search was conducted on published literature (e.g. PubMed) and Internet sources to identify information relevant to ketamine's rapid-acting antidepressant action and, specifically, to the possible mechanism(s) of this action. Key search words included 'ketamine', 'antidepressant', 'mechanism of action', 'depression' and 'rapid acting', either individually or in combination. Information was sought that would include less well-known, as well as well-known, basic pharmacologic properties of ketamine and that identified and evaluated the several hypotheses about ketamine's mechanism of antidepressant action. RESULTS: Whether the mechanistic explanation for ketamine's rapid-onset antidepressant action is related to its well-known antagonism of the NMDA (N-Methyl-d-aspartate) subtype of glutamate receptor or to something else has not yet been fully elucidated. The evidence from pharmacologic, medicinal chemistry, animal model and drug-discovery sources reveals a wide variety of postulated mechanisms. WHAT IS NEW AND CONCLUSION: The surprising discovery of ketamine's rapid-onset antidepressant effect is a game-changer for the understanding and treatment of depressive illness. There is some convergence on NMDA receptor antagonism as a likely, but to date unproven, common mechanism. The surprising number of other mechanisms, and the several novel biochemical aetiologies of depression proposed, suggests exciting new drug-discovery targets.

Atrial fibrillation in older inpatients: are there any differences in clinical characteristics and pharmacological treatment between the frail and the non-frail?

BACKGROUND: Frailty is common in patients with atrial fibrillation and may impact on antithrombotic and anti-arrhythmic treatment. AIM: To describe differences in clinical characteristics, prescription of antithrombotic and anti-arrhythmic medications and incidence of haemorrhage and stroke, between frail and non-frail older inpatients. METHODS: Prospective observational study in patients aged ≥65 years with atrial fibrillation admitted to a teaching hospital in Sydney, Australia. Frailty was assessed using the Reported Edmonton Frail Scale, stroke risk with CHA2DS2-VASc score and bleeding risk with HAS-BLED score. Participants were followed after 6 months for haemorrhages and strokes. RESULTS: We recruited 302 patients (mean age 84.7 ± 7.1 years, 53.3% frail, 50% female, mean CHA2DS2-VASc 4.61 ± 1.44, mean HAS-BLED 2.97 ± 1.04). Frail participants were older and had more co-morbidities and higher risk of stroke but not haemorrhage. Upon discharge, 55.7% participants were prescribed with anticoagulants (49.3% frail, 62.6% non-frail, P = 0.02). Thirty-three per cent received antiplatelets only and 11.1% no antithrombotics, with no difference by frailty status. For anti-arrhythmics, 52.6% received rate-control drugs only, 11.8% rhythm-control drugs only and 13.5% both and 22.1% were not prescribed either, with no difference by frailty status. On univariate logistic regression, frailty decreased the likelihood of anticoagulant prescription (odds ratio (OR) 0.58, 95%CI 0.36-0.93), but this was not significant on multivariate analysis (OR 0.66, 95%CI 0.40-1.11). After 6 months, overall incidence of ischaemic stroke was 2.1%, and in patients taking anticoagulants, incidence of major/severe bleeding was 6.3%, with no significant difference between frailty groups. CONCLUSIONS: Frailty status had little impact on antithrombotic prescription and no impact on anti-arrhythmic prescription.

Modulation contrast optimization for wavelength conversion of a 20 Gbit/s data signal in hybrid InP/SOI photonic crystal nanocavity.

Photonic crystal cavity-based switching is studied both theoretically and experimentally in order to identify the best configuration to maximize "wavelength conversion" efficiency. In particular, it is shown that an enhanced contrast can be reached when the probe is blueshifted with respect to the resonance. The use of an InP/SOI hybrid photonic crystal nanocavity is reported for the first time for all-optical error-free "wavelength conversion" at 20 Gbit/s with a nonreturn to zero on-off keying signal.

Tuberculosis relapse in Vietnam is significantly associated with Mycobacterium tuberculosis Beijing genotype infections.

BACKGROUND: In Vietnam, the Mycobacterium tuberculosis Beijing genotype is associated with multi-drug resistance and is emerging. A possible explanation for this genotype's success is an increased rate of relapse. METHODS: In a prospective cohort study, isolates from patients with smear-positive tuberculosis were subjected to drug susceptibility testing and to spoligotyping and variable number of tandem repeats typing before treatment and after recurrence of tuberculosis. RESULTS: Among 1068 patients who were actively followed up over 18 months for recurrence, 23 relapse cases occurred (1.39 cases/100 person-years). After adjustment for genotype, tuberculosis treatment history, and drug resistance, relapse was significantly associated with the Beijing genotype (adjusted hazard ratio [aHR], 5.48; 95% confidence interval [CI], 2.06-14.55) and isoniazid resistance (aHR, 5.91; 95% CI, 2.16-16.16). CONCLUSIONS: The strongly increased relapse rate in tuberculosis cases caused by Beijing strains probably contributes to the successful spread of this genotype in Vietnam and elsewhere.

Strengthening cardiac therapy pipelines using human pluripotent stem cell-derived cardiomyocytes.

Advances in hiPSC isolation and reprogramming and hPSC-CM differentiation have prompted their therapeutic application and utilization for evaluating potential cardiovascular safety liabilities. In this perspective, we showcase key efforts toward the large-scale production of hiPSC-CMs, implementation of hiPSC-CMs in industry settings, and recent clinical applications of this technology. The key observations are a need for traceable gender and ethnically diverse hiPSC lines, approaches to reduce cost of scale-up, accessible clinical trial datasets, and transparent guidelines surrounding the safety and efficacy of hiPSC-based therapies.

Perlecan (HSPG2) promotes structural, contractile, and metabolic development of human cardiomyocytes.

Perlecan (HSPG2), a heparan sulfate proteoglycan similar to agrin, is key for extracellular matrix (ECM) maturation and stabilization. Although crucial for cardiac development, its role remains elusive. We show that perlecan expression increases as cardiomyocytes mature in vivo and during human pluripotent stem cell differentiation to cardiomyocytes (hPSC-CMs). Perlecan-haploinsuffient hPSCs (HSPG2+/-) differentiate efficiently, but late-stage CMs have structural, contractile, metabolic, and ECM gene dysregulation. In keeping with this, late-stage HSPG2+/- hPSC-CMs have immature features, including reduced ⍺-actinin expression and increased glycolytic metabolism and proliferation. Moreover, perlecan-haploinsuffient engineered heart tissues have reduced tissue thickness and force generation. Conversely, hPSC-CMs grown on a perlecan-peptide substrate are enlarged and display increased nucleation, typical of hypertrophic growth. Together, perlecan appears to play the opposite role of agrin, promoting cellular maturation rather than hyperplasia and proliferation. Perlecan signaling is likely mediated via its binding to the dystroglycan complex. Targeting perlecan-dependent signaling may help reverse the phenotypic switch common to heart failure.

Epidemiology of isoniazid resistance mutations and their effect on tuberculosis treatment outcomes.

Isoniazid resistance is highly prevalent in Vietnam. We investigated the molecular and epidemiological characteristics and the association with first-line treatment outcomes of the main isoniazid resistance mutations in Mycobacterium tuberculosis in codon 315 of the katG and in the promoter region of the inhA gene. Mycobacterium tuberculosis strains with phenotypic resistance to isoniazid from consecutively diagnosed smear-positive tuberculosis patients in rural Vietnam were subjected to Genotype MTBDRplus testing to identify katG and inhA mutations. Treatment failure and relapse were determined by sputum culture. In total, 227 of 251 isoniazid-resistant strains (90.4%) had detectable mutations: 75.3% in katG codon 315 (katG315) and 28.2% in the inhA promoter region. katG315 mutations were significantly associated with pretreatment resistance to streptomycin, rifampin, and ethambutol but not with the Beijing genotype and predicted both unfavorable treatment outcome (treatment failure or death) and relapse; inhA promoter region mutations were only associated with resistance to streptomycin and relapse. In tuberculosis patients, M. tuberculosis katG315 mutations but not inhA mutations are associated with unfavorable treatment outcome. inhA mutations do, however, increase the risk of relapse, at least with treatment regimens that contain only isoniazid and ethambutol in the continuation phase.

Normal dispersion femtosecond fiber optical parametric oscillator.

We propose and demonstrate a synchronously pumped fiber optical parametric oscillator (FOPO) operating in the normal dispersion regime. The FOPO generates chirped pulses at the output, allowing significant pulse energy scaling potential without pulse breaking. The output average power of the FOPO at 1600 nm was ∼60 mW (corresponding to 1.45 nJ pulse energy and ∼55% slope power conversion efficiency). The output pulses directly from the FOPO were highly chirped (∼3 ps duration), and they could be compressed outside of the cavity to 180 fs by using a standard optical fiber compressor. Detailed numerical simulation was also performed to understand the pulse evolution dynamics around the laser cavity. We believe that the proposed design concept is useful for scaling up the pulse energy in the FOPO using different pumping wavelengths.

Clustering of Beijing genotype Mycobacterium tuberculosis isolates from the Mekong delta in Vietnam on the basis of variable number of tandem repeat versus restriction fragment length polymorphism typing.

BACKGROUND: In comparison to restriction fragment length polymorphism (RFLP) typing, variable number of tandem repeat (VNTR) typing is easier to perform, faster and yields results in a simple, numerical format. Therefore, this technique has gained recognition as the new international gold standard in typing of Mycobacterium tuberculosis. However, some reports indicated that VNTR typing may be less suitable for Beijing genotype isolates. We therefore compared the performance of internationally standardized RFLP and 24 loci VNTR typing to discriminate among 100 Beijing genotype isolates from the Southern Vietnam. METHODS: Hundred Beijing genotype strains defined by spoligotyping were randomly selected and typed by RFLP and VNTR typing. The discriminatory power of VNTR and RFLP typing was compared using the Bionumerics software. RESULTS: Among 95 Beijing strains available for analysis, 14 clusters were identified comprising 34 strains and 61 unique profiles in 24 loci VNTR typing ((Hunter Gaston Discrimination Index (HGDI = 0.994)). 13 clusters containing 31 strains and 64 unique patterns in RFLP typing (HGDI = 0.994) were found. Nine RFLP clusters were subdivided by VNTR typing and 12 VNTR clusters were split by RFLP. Five isolates (5%) revealing double alleles or no signal in two or more loci in VNTR typing could not be analyzed. CONCLUSIONS: Overall, 24 loci VNTR typing and RFLP typing had similar high-level of discrimination among 95 Beijing strains from Southern Vietnam. However, loci VNTR 154, VNTR 2461 and VNTR 3171 had hardly added any value to the level of discrimination.

Nontuberculous mycobacterial disease in patients with HIV in Southeast Asia.

RATIONALE: Although nontuberculous mycobacteria (NTM) are widely documented as a cause of illness among HIV-infected people in the developed world, studies describing the prevalence of NTM disease among HIV-infected people in most resource-limited settings are rare. OBJECTIVES: To evaluate the prevalence of mycobacterial disease in HIV-infected patients in Southeast Asia. METHODS: We enrolled people with HIV from three countries in Southeast Asia and collected pulmonary and extrapulmonary specimens to evaluate the prevalence of mycobacterial disease. We adapted American Thoracic Society/Infectious Disease Society of America guidelines to classify patients into NTM pulmonary disease, NTM pulmonary disease suspects, NTM disseminated disease, and no NTM categories. MEASUREMENTS AND MAIN RESULTS: In Cambodia, where solid media alone was used, NTM was rare. Of 1,060 patients enrolled in Thailand and Vietnam, where liquid culture was performed, 124 (12%) had tuberculosis and 218 (21%) had NTM. Of 218 patients with NTM, 66 (30%) were classified as NTM pulmonary disease suspects, 9 (4%) with NTM pulmonary disease, and 10 (5%) with NTM disseminated disease. The prevalence of NTM disease was 2% (19 of 1,060). Of 51 patients receiving antiretroviral therapy (ART), none had NTM disease compared with 19 (2%) of 1,009 not receiving ART. CONCLUSIONS: Although people with HIV frequently have sputum cultures positive for NTM, few meet a strict case definition for NTM disease. Consistent with previous studies, ART was associated with lower odds of having NTM disease. Further studies of NTM in HIV-infected individuals in tuberculosis-endemic countries are needed to develop and validate case definitions.