Toll-like receptor 2 and Toll-like receptor 4 polymorphisms and susceptibility to asthma and allergic rhinitis: a case-control analysis

The aim of the study was to investigate whether polymorphisms in genes encoding Toll-like receptors (TLR2 and TLR4) may modify relative risk for development of asthma or allergic rhinitis. The results showed that the genotype and allele frequencies of the TLR2 Arg753Gln and TLR4 Asp299Gly polymorphisms were not significantly different between asthmatic children or allergic rhinitis when compared to controls (p>0.05 for each) or even when compared further with IgE level. However, it was shown that the mutant allele of TLR2 or TLR4 polymorphisms were significantly associated with the moderate-severe group compared to the mild group in both atopic asthmatics and allergic rhinitis group (p>0.001 for each). In conclusion, our study demonstrates a lack of association of TLR2 and TLR4 polymorphisms with asthma and allergic rhinitis but suggests significant association between these genetic variants and the disease severity.     

Zoonotic transmission of tuberculosis between pastoralists and their livestock in South-East Ethiopia

Despite huge global efforts in tuberculosis (TB) control, pastoral areas remain under-investigated. During two years sputum and fine needle aspirate (FNA) specimens were collected from 260 Ethiopian pastoralists of Oromia and Somali Regional States with suspected pulmonary TB and from 32 cases with suspected TB lymphadenitis. In parallel, 207 suspected tuberculous lesions were collected from cattle, camels and goats at abattoirs. All specimens were processed and cultured for mycobacteria; samples with acid-fast stained bacilli (AFB) were further characterized by molecular methods including genus and deletion typing as well as spoligotyping. Non-tuberculous mycobacteria (NTM) were sequenced at the 16S rDNA locus. Culturing of AFB from human sputum and FNA samples gave a yield of 174 (67%) and 9 (28%) isolates, respectively. Molecular typing was performed on 173 of these isolates and 160 were confirmed as Mycobacterium tuberculosis, three as M. bovis, and the remaining 10 were typed as NTMs. Similarly, 48 AFB isolates (23%) yielded from tuberculous lesions of livestock, of which 39 were molecular typed, including 24 M. bovis and 4 NTMs from cattle, 1 M. tuberculosis and 1 NTM from camels and 9 NTMs from goats. Isolation of M. bovis from humans and M. tuberculosis from livestock suggests transmission between livestock and humans in the pastoral areas of South-East Ethiopia.     

Geographic differences in genetic susceptibility to IgA nephropathy: GWAS replication study and geospatial risk analysis

IgA nephropathy (IgAN), major cause of kidney failure worldwide, is common in Asians, moderately prevalent in Europeans, and rare in Africans. It is not known if these differences represent variation in genes, environment, or ascertainment. In a recent GWAS, we localized five IgAN susceptibility loci on Chr.6p21 (HLA-DQB1/DRB1, PSMB9/TAP1, and DPA1/DPB2 loci), Chr.1q32 (CFHR3/R1 locus), and Chr.22q12 (HORMAD2 locus). These IgAN loci are associated with risk of other immune-mediated disorders such as type I diabetes, multiple sclerosis, or inflammatory bowel disease. We tested association of these loci in eight new independent cohorts of Asian, European, and African-American ancestry (N = 4,789), followed by meta-analysis with risk-score modeling in 12 cohorts (N = 10,755) and geospatial analysis in 85 world populations. Four susceptibility loci robustly replicated and all five loci were genome-wide significant in the combined cohort (P = 5×10⁻³²–3×10⁻¹⁰), with heterogeneity detected only at the PSMB9/TAP1 locus (I² = 0.60). Conditional analyses identified two new independent risk alleles within the HLA-DQB1/DRB1 locus, defining multiple risk and protective haplotypes within this interval. We also detected a significant genetic interaction, whereby the odds ratio for the HORMAD2 protective allele was reversed in homozygotes for a CFHR3/R1 deletion (P = 2.5×10⁻⁴). A seven–SNP genetic risk score, which explained 4.7% of overall IgAN risk, increased sharply with Eastward and Northward distance from Africa (r = 0.30, P = 3×10⁻¹²⁸). This model paralleled the known East–West gradient in disease risk. Moreover, the prediction of a South–North axis was confirmed by registry data showing that the prevalence of IgAN–attributable kidney failure is increased in Northern Europe, similar to multiple sclerosis and type I diabetes. Variation at IgAN susceptibility loci correlates with differences in disease prevalence among world populations. These findings inform genetic, biological, and epidemiological investigations of IgAN and permit cross-comparison with other complex traits that share genetic risk loci and geographic patterns with IgAN.     

On the lattice Boltzmann method simulation of a two-phase flow bioreactor for artificially grown cartilage cells

Owing to the growing demand of cartilage tissue repair and transplants, engineered cartilage cells have emerged as a prospective solution. Several bioreactors were built for artificially grown cartilage cells. In this work, a recently designed flow bed bioreactor is numerically investigated and compared with experimental results.The flow field inside the bioreactor was modelled using the lattice Boltzmann method. The flow consists of two phases which are the liquid component (nutrition supply) and gas component (oxygen supply). The flow field is simulated using the multi-phase lattice Boltzmann method, whilst the cell activity is modelled using Michaelis–Menten kinetics.The oxygen diffusion level at the exit of the nutrition phase is used as an evaluation process between the numerical and experimental results reporting the possibility of using the proposed model to fully simulate such bioreactors, though greatly saving time and money. Shear stress and pressure distributions are as well compared with published human cartilage load measurements to estimate the dynamic similarity between the bioreactor and the human knee. The predicted oxygen levels proved consistent trends with the experimental work with a 7% difference after 1 h measuring time. The shear stress levels recorded 10–11 orders of magnitude lower than in humans and also one order of magnitude lower in the pressure distribution.     

Osteoblastic cells: differentiation and trans-differentiation

The osteoblast is the bone forming cell and is derived from mesenchymal stem cells (MSC) present among the bone marrow stroma. MSC are capable of multi-lineage differentiation into mesoderm-type cells such as osteoblasts and adipocytes. Understanding the mechanisms underlying osteoblast differentiation from MSC is a central topic in bone biology that can provide insight into mechanisms of bone maintenance and also novel pharmacological targets to increase osteoblast differentiation and consequently bone formation.     

Microsatellite markers identify three additional quantitative trait loci for resistance to soybean sudden-death syndrome (SDS) in Essex × Forrest RILs

Resistance to the sudden-death syndrome (SDS) of soybean (Glycine max L. Merr.), caused by Fusarium solani f. sp. glycines, is controlled by a number of quantitatively inherited loci (QTLs). Forrest showed a strong field resistance to SDS while Essex is susceptible to SDS. A population of 100 recombinant inbred lines (RILs) derived from a cross of Essex × Forrest was used to map the loci effecting resistance to SDS using phenotypic data obtained from six environments. Six loci involved in resistance to SDS were identified in this population. Four of the QTLs identified by BARC-Satt214 (P = 0.0001, R²= 24.1%), BARC-Satt309 (P = 0.0001, R² = 16.3), BARC-Satt570 (P = 0.0001, R² = 19.2%) and a random amplified polymorphic DNA (RAPD) marker OEO2₁₀₀₀ (P = 0.0031, R²=12.6) were located on linkage group (LG) G (Satt309 and OEO2₁₀₀₀ were previously reported). Jointly the four QTLs on LG G explained 50% of the variation in SDS disease incidence (DI). All the QTLs on LG G derived the beneficial allele from Forrest. Two QTLs, BARC-Satt371 (P = 0.0019, R² = 12%) on LG C2 (previously reported) and BARC-Satt354 (P = 0.0015, R² = 11.5%) on LG I, derived their beneficial allele from Essex and jointly explained about 40% of the variation in SDS DI. Two-way and multi-way interactions indicated that gene action was additive among the loci underlying resistance to SDS. These results suggest that cultivars with durable resistance to SDS can be developed via gene pyramiding. Received: 19 January 2000 / Accepted: 30 April 2000     

Morphological and morphometrical analysis of Heterodera spp. populations in Jordan

Phenotypic diversity of five Jordanian populations of cyst nematodes, Heterodera spp. collected from five regions from Jordan (Ar-Ramtha, Madaba, Dana, Al-Karak, and Jerash) was investigated. Soil samples were collected from one representative field in each region. Morphological and morphometrical characteristics revealed that Heterodera latipons is dominated in cereal fields at Ar-Ramtha, Madaba, Dana and Al-Karak regions and Heterodera schachtii in Jerash. Cysts populations from all cereal fields had bifenestrate vulval cone and a strong underbridge. Wherever, cysts of the cabbage population had ambifenestrate vulval cone with long vulval slit. The bullae were absent in Ar-Ramtha, Madaba and Dana populations, but present in Al-Karak and Jerash. Based on 12 morphometrical characters, the first three functions in canonical discriminant analysis accounted 99.3% of the total variation. Distance from dorsal gland duct opening to stylet base, underbridge length, a = L/W (body length/midbody width) and length of hyaline tail tip had strong and significant contributions in the first function. While the second function was strongly influenced by length of hyaline tail, fenestral length, fenestral width and tail length. However, the third canonical discriminate function was found to be influenced by stylet length, fenestral length, a = L/W (body length/midbody width) and underbridge width. The graphical representation of the distribution of the samples showed that the first canonical discriminant function clearly separated H. schachtii from Jerash from other populations. Whereas, H. latipons collected from Madaba and Dana were clearly separated in the second function. The results indicated that differences at morphological and morphometrical levels revealed diverse populations of Heterodera spp. in Jordan.     

Gas chromatography-mass spectrometry of isobutyl ester trimethylsilyl ether derivatives of bile acids and application to the study of bile sterol and bile acid biosynthesis in rat liver epithelial cell lines

The derivatization of bile acids into trimethylsilyl ether isobutyl ester (IBTMS) and of neutral sterols into trimethylsilyl ether (TMS) allowed the separation on an OV-1 capillary gas chromatography column of 15 bile steroids as follows: cholesterol, 7 alpha-hydroxycholesterol, 6 beta-hydroxycholesterol, 6 alpha-hydroxycholesterol, 7 beta-hydroxycholesterol, lithocholate, deoxycholate, 25-hydroxycholesterol, chenodeoxycholate, cholate, murocholate, hyodeoxycholate, ursodeoxycholate, hyocholate, and beta-muricholate. Fragmentation data of the coupled gas chromatographic-mass spectrometric (GC-MS) analysis of these nine bile acids as IBTMS derivatives under electron impact and chemical ionizations (methane, isobutane, and ammonia) are given. The ammonia chemical ionization appears to be the best mode for compound identification and quantitation due to fragmentations into high mass ions. The comparison of methylene units of the five sterols as TMS derivatives and of each type of methyl, TMS, or isobutyl ester of the nine bile acids as TMS ethers showed that isobutyl esterification increased dramatically the retention time of the bile acids, allowing their separation after the neutral sterols. Different methods of GC-MS analysis were applied to the study of bile steroid secretion in long-term rat liver epithelial cell lines, either serum-supplemented cell lines or serum-free cell lines, growing in serum-free medium since the primary explanation or after adaptation of serum-supplemented lines to this medium. It is demonstrated for the first time that liver epithelial cell lines maintain the metabolic pathway leading from synthesized cholesterol to dioxygenated sterols and the two normal main primary bile acids of the liver, chenodeoxycholic acid and cholic acid, up to 32-47% of the in vivo daily rate, and in addition the production of alpha-muricholic acid, the bile acid marker of murine liver.     

Hyperbaric oxygne tolerance in newborn mammals-hypothesis on mechanisms and outcome

Newborn mammals, compared to adults, are extremely resistant to the CNS effects of hyperbaric oxygenation (HBO) induced by excessive generation of reactive oxygen species. This tolerance to HBO may be related to either physiological responses or the chemical characteristics of the immature brain, including a low cerebral blood flow and energy metabolism and a low concentration of polyunsaturated fatty acids. In adult mammals the main protective mechanism against CNS oxygen toxicity, besides endogenous antioxidants, is a transient HBO-induced cerebral vasoconstriction. How cerebral vasculature reacts to HBO in the immature brain is not known. We present indirect evidence suggesting that HBO in newborn rats induces a persistent cerebral vasoconstriction concurrently with a severe and maintained reduction in ventilation. It is speculated that the outcome of these physiologic responses to hyperoxic exposures may be: (a) extension of tolerance to both CNS and pulmonary oxygen poisoning; (b) creation of a profound hypoxic-ischemic condition in vulnerable neural structures: and (c) impairement of the circulatory and ventilatory responses to hypoxic stimuli on return to air consequent development of a secondary hypoxic-ischemic condition. These hypothetical pre- and post-HBO events may set the stage for the development of some delayed neurological disorders, including the retinopathy of prematurity and the retardation of brain development in fetuses or prematurely-born infants subjected to oxygen therapy.