Potentiality of the cox1 gene in the taxonomic resolution of soil fungi

We explored the potential of the cox1 gene in the species resolution of soil fungi and compared it with the nuclear internal transcribed spacer (ITS) and small subunit (SSU)-rDNA. Conserved primers allowing the amplification of the fungal cox1 gene were designed, and a total of 47 isolates of Zygomycota and Ascomycota were investigated. The analysis revealed a lack of introns in >90% of the isolates. Comparison of the species of each of the six studied genera showed high interspecific sequence polymorphisms. Indeed, the average of nucleotide variations (4.2–11%) according to the genus, due mainly to the nucleotide substitutions, led to the taxonomic resolution of all the species studied regarding both ITS and SSU-rDNA, in which <88% were discriminated. The phylogenetic analysis performed after alignment of the cox1 gene across distant fungal species was in accordance with the well-known taxonomic position of the species studied and no overlap was observed between intra- and interspecific variations. These results clearly demonstrated that the cox1 sequences could provide good molecular markers for the determination of the species composition of environmental samples and constitute an important advance to study soil fungal biodiversity.     

Fluid–structure interaction analysis of the left coronary artery with variable angulation

The aim of this study is to elucidate the correlation between coronary artery branch angulation, local mechanical and haemodynamic forces at the vicinity of bifurcation. Using a coupled fluid–structure interaction (FSI) modelling approach, five idealized left coronary artery models with various angles ranging from 70° to 110° were developed to investigate the influence of branch angulations. In addition, one CT image-based model was reconstructed to further demonstrate the medical application potential of the proposed FSI coupling method. The results show that the angulation strongly alters its mechanical stress distribution, and the instantaneous wall shear stress distributions are substantially moderated by the arterial wall compliance. As high tensile stress is hypothesized to cause stenosis, the left circumflex side bifurcation shoulder is indicated to induce atherosclerotic changes with a high tendency for wide-angled models.     

A review of taeniasis and cysticercosis in the Lao People's Democratic Republic

Taeniasis and cysticercosis are important but underreported parasitic zoonoses in the Lao People's Democratic Republic (Lao PDR). Reports of human and pig cysticercosis are rather limited and based largely on anecdotal evidence. To date, no structured surveys of disease prevalence or incidence have been reported. However, one unpublished pilot survey of pig cysticercosis in a slaughterhouse in northern Laos estimated prevalence to be 1.7%, without speciation of parasite cysts. Over the past 20 years, nine surveys of intestinal helminthic infection have been conducted; the prevalence of human taeniasis ranged from 0 to 14.0%. The study designs and sample sizes varied greatly, however a high degree of spatial and age variation in taeniasis prevalence was evident. These results are however inconclusive as the species of tapeworm infecting the people was not determined. To further our knowledge of taeniasis and cysticercosis in Lao PDR, structured community-based surveys in high-risk areas are required in combination with the use of sensitive and specific diagnostic tests capable of identifying the pork tapeworm, Taenia solium. This will enable the development and implementation of control measures that are both appropriate and sustainable if T. solium is shown to be a public health threat.     

Biodiversity of Asian rice gall midge (Orseolia oryzae Wood Mason) from five countries examined by AFLP analysis.

Amplified fragment length polymorphism (AFLP) analysis was used to assess the biodiversity of one of the most important dipteran pests of cereals, the Asian rice gall midge (Orseolia oryzae Wood Mason). Larvae and pupae were collected at 15 locations in five Asian countries and preserved in 95% ethanol for storage, shipment, and DNA extraction using cetyltrimethylammonium bromide (CTAB). Although only approximately 1 microg of DNA was extracted from a single pupa or larva, the use of several AFLP primers in various combinations meant that this amount of DNA was sufficient to allow many DNA fingerprints to be made per individual. Fingerprints were sufficiently reproducible, especially during selective amplification, to allow the genetic diversity within a field population to be characterized. Extraction of DNA from a pool of 20 insects yielded AFLP fingerprints in which variation among individuals was sacrificed in favor of detecting differences among populations. For each location, pooled DNA was amplified with three primer pairs. A total of 261 distinct AFLP bands were identified for the 45 fingerprints. Cluster analysis, performed by the unweighted pair-group method (UPGMA), separated the populations into two distinct groups. Group I included two populations from Guangdong province of southern China and one each from Laos and Imphal in northeastern India, while group II was comprised of eleven populations from elsewhere in India (Assam, Orissa, Madhya Pradesh, Andhra Pradesh, and Kerala) and from Nepal and Sri Lanka. AFLP analysis provided insight into the origins of gall midge biotypes. In 1992, the prevailing biotype in Imphal changed from Indian biotype 3 to a new biotype 3M. Our data show that biotype 3M belongs to group I and did not arise by a recent mutation from biotype 3, which belongs to group II. By contrast, Indian biotypes 2 and 4 are likely to have diverged through recent mutation and selection, as are Chinese biotypes 1 and 4. The almost simultaneous emergence of new biotypes in Kerala and Sri Lanka during 1985-1988 was most probably coincidental, because these biotypes are not closely related. AFLP fingerprints were also able to detect sexual dimorphism in the DNA of adult gall midges and to distinguish gall midge from its major parasite Platygaster oryzae.     

Numerical modelling of nanoparticle deposition in the nasal cavity and the tracheobronchial airway

Recent advances in nanotechnology have seen the manufacture of engineered nanoparticles for many commercial and medical applications such as targeted drug delivery and gene therapy. Transport of nanoparticles is mainly attributed to the Brownian force which increases as the nanoparticle decreases to 1 nm. This paper first verifies a Lagrangian Brownian model found in the commercial computational fluid dynamics software Fluent before applying the model to the nasal cavity and the tracheobronchial (TB) airway tree with a focus on drug delivery. The average radial dispersion of the nanoparticles was 9x greater for the user-defined function model over the Fluent in-built model. Deposition in the nasal cavity was high for very small nanoparticles. The particle diameter range in which the deposition drops from 80 to 18% is between 1 and 10 nm. From 10 to 150 nm, however, there is only a small change in the deposition curve from 18 to 15%. A similar deposition curve profile was found for the TB airway.     

CFD simulation of aerosol delivery to a human lung via surface acoustic wave nebulization

Administration of drug in the form of particles through inhalation is generally preferable in the treatment of respiratory disorders. Conventional inhalation therapy devices such as inhalers and nebulizers, nevertheless, suffer from low delivery efficiencies, wherein only a small fraction of the inhaled drug reaches the lower respiratory tract. This is primarily because these devices are not able to produce a sufficiently fine drug mist that has aerodynamic diameters on the order of a few microns. This study employs computational fluid dynamics to investigate the transport and deposition of the drug particles produced by a new aerosolization technique driven by surface acoustic waves (SAWs) into an in silico lung model geometrically reconstructed using computed tomography scanning. The particles generated by the SAW are released in different locations in a spacer chamber attached to a lung model extending from the mouth to the 6th generation of the lung bronchial tree. An Eulerian approach is used to solve the Navier–Stokes equations that govern the airflow within the respiratory tract, and a Lagrangian approach is adopted to track the particles, which are assumed to be spherical and inert. Due to the complexity of the lung geometry, the airflow patterns vary as it penetrates deeper into the lung. High inertia particles tend to deposit at locations where the geometry experiences a significant reduction in cross section. Our findings, nevertheless, show that the injection location can influence the delivery efficiency: Injection points close to the spacer centerline result in deeper penetration into the lung. Additionally, we found that the ratio of drug particles entering the right lung is significantly higher than the left lung, independent of the injection location. This is in good agreement with this fact that the most of airflow enters to the right lobes.     

Numerical modelling of nanoparticle deposition in the nasal cavity and the tracheobronchial airway

Recent advances in nanotechnology have seen the manufacture of engineered nanoparticles for many commercial and medical applications such as targeted drug delivery and gene therapy. Transport of nanoparticles is mainly attributed to the Brownian force which increases as the nanoparticle decreases to 1 nm. This paper first verifies a Lagrangian Brownian model found in the commercial computational fluid dynamics software Fluent before applying the model to the nasal cavity and the tracheobronchial (TB) airway tree with a focus on drug delivery. The average radial dispersion of the nanoparticles was 9x greater for the user-defined function model over the Fluent in-built model. Deposition in the nasal cavity was high for very small nanoparticles. The particle diameter range in which the deposition drops from 80 to 18% is between 1 and 10 nm. From 10 to 150 nm, however, there is only a small change in the deposition curve from 18 to 15%. A similar deposition curve profile was found for the TB airway.     

Impact of modernization on oxidative stress among indigenous populations in northern Laos

Objectives

To explore the impact of modernization on oxidative stress during a momentous health transition process, we investigated differences in oxidative stress among the indigenous populations of villages in northern Laos with different levels of modernization.

Methods

We conducted a cross-sectional study of 380 adults in three villages with different levels of modernization. Three biomarkers related to oxidative stress were measured: urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) and 8-isoprostane concentrations (both measured by liquid chromatography–tandem mass spectrometry), and blood telomere length (measured with qPCR). We examined associations between village-level modernization and oxidative stress-related biomarkers in a multilevel analysis including a random effect and covariates.

Results

The geometric means of urinary 8-OHdG and 8-isoprostane concentrations were 2.92 and 0.700 μg/g creatinine, respectively, in our study population. Higher urinary 8-OHdG concentrations and shorter telomeres were observed in participants from the more modernized villages, whereas urinary 8-isoprostane concentrations did not differ significantly among villages.

Conclusions

Our findings imply that modernization-induced changes in lifestyle may increase oxidative DNA damage. Baseline levels of oxidative lipid damage are expected to be high in the indigenous populations of northern Laos. Assessments of oxidative stress may provide valuable insights into the mechanisms of health transition in specific populations.