Ameliorating Effect of Osteopontin on H<Subscript>2</Subscript>O<Subscript>2</Subscript>-Induced Apoptosis of Human Oligodendrocyte Progenitor Cells

Recently our group used oligodendrocyte progenitor cells (OPCs) as appropriate model cells to pinpoint the mechanism of the progress of neurodegenerative disorders. In the present study, we focused on the therapeutic role of osteopontin (OPN), a secreted glycosylated phosphoprotein, involved in a number of physiological events including bone formation and remodeling, immune responses, and tumor progression. Protective role of OPN, as a negative regulator of tumorigenesis, has already been clarified. Human embryonic stem cell-derived OPCs were pretreated with OPN before induction of apoptosis by H₂O₂. Data indicated that OPN prohibited cell death and enhanced OPC viability. This effect is achieved through reduction of apoptosis and induction of anti-apoptosis markers. In addition OPN induces expression of several integrin subunits, responsible for OPN interaction. Notably, our findings showed that expression of αV β1/β3/β5 and β8 integrins increased in response to OPN, while treatment with H₂O₂ down-regulated αV β1/β5 and β8 integrins expression significantly. In conclusion, OPN may act via αV integrin signaling and trigger suppression of P53-dependent apoptotic cascades. Therefore OPN therapy may be considered as a feasible process to prevent progress of neurodegenerative diseases in human.     

Towards the conservation of a critically endangered species, <Emphasis Type="Italic">Aphanius farsicus</Emphasis>: embryogenesis and development

Human-induced disturbance or anthropogenic activities, natural disturbance and also limited distribution, have forced Aphanius farsicus populations to the edge of extinction, during the past few years. As knowledge of fish ontogeny is fundamental for accurate stock assessment, and reproductive potential determination, thus for future conservation and management of the critically endangered species, we describe the first detailed normal embryonic development of this cyprinodontid fish from fertilization to post-hatching. Aphanius farsicus spontaneously spawned at 24°C. The newly-laid eggs were hyaline and spherical in shape (1.40 ± 0.02 mm, n = 11), sticky and full of egg yolk (telolecithal/macrolecithal) with oil droplets. We documented the main developmental stages at 24°C to zygote (0 h), cleavage (2 h), blastula (2 h), gastrula (17 h), segmentation, (34 h), pharyngula (100 h) and hatching (162 h).     

Early otolith development in the critically endangered tooth-carp, <Emphasis Type="Italic">Aphanius farsicus</Emphasis> (Teleostei: Cyprinodontidae)

Otolith morphology in the tooth-carp/killifish genus Aphanius is a source of informative taxonomic characters at both the species and population level. Most work on otoliths has focused on adult specimens, while evidence of ontogenetic variation is rarely provided. In this study we describe the development of otolith morphology during the early life stages of an endangered and endemic species, the Fars tooth-carp Aphanius farsicus from southern Iran. The study material comprises 34 larvae and early juveniles representing nine different developmental stages (0–120 days post hatching), all reared under the same laboratory conditions. The results reveal (i) a significant correlation between standard length and otolith size (length) in larval and early juvenile stages, (ii) clear differences in otolith morphology between larvae/early juveniles and adults, and (iii) a temporal link between the appearance of the sulcus on the otolith’s inner face and the emergence of the dorsal and anal fins. Our results indicate that otoliths of Aphanius can be recognized as originating from larval or early juvenile fish based on their short rostrum and antirostrum lengths and wide excisura, in addition to their small size. These immature otoliths are, however, not diagnostic at the species level in A. farsicus, nor most probably in other species of tooth-carp. The outcome of our study is also of interest to palaeontologists working with fossil killifish otoliths, as it can help avoid misinterpretation of ancient species diversity.     

Sensitivity to house dust mite allergens and prevalence of allergy-causing house dust mite species in Pothwar,Pakistan

This study is the first report on the epidemiological status of house dust mite (HDM) allergy in Pothwar, Pakistan. Allergy data of 2087 symptomatic patients were obtained, of whom 1706 (81.7%) patients were skin-prick-test positive for HDM allergens. This percentage was significantly higher than for pollen and food allergens. In the results of this study Dermatophagoides farinae (61%) and D. pteronyssinus (29%) were the predominant species in the study area. Besides these pyroglyphids, predatory Cheyletus sp. (10%) and an oribatid mite sp. (1%) were also observed. Random and patients’ houses showed 87.4 and 87.1% positive mite infestation, respectively. Mean (±?SEM) D. farinae counts per g of dust in random samples was 235.4 ± 7.93 compared to 274.7 ± 10.78 from patients’ homes. Mean D. pteronyssinus counts from random houses compared to patients’ houses were 115.0 ± 4.57 and 124.6 ± 5.76, respectively. Mite counts depicted seasonal variation, with peaks during monsoon season. ELISA results of dust samples demonstrated that of the dust samples with?>?10 µg/g of dust, the threshold value described as a risk factor for developing asthma, 57.6% had Der f1 and 20% Der p1 allergen load. Mean Der f1 burden was significantly higher than Der p1, with maximum levels during monsoon and autumn seasons. This research established a better awareness about the epidemiological status of HDM allergy and prevalence of allergy causing HDM species in Pakistan.     

Degradation of aflatoxin by Aspergillus flavus

Aflatoxin degradative activity was demonstrated in 6- to 12-d-old intact mycelium and cell-free extracts of Aspergillus flavus. The addition of cycloheximide, SKF 525-A or metyrapone to cultures of A. flavus prevented subsequent degradation of the aflatoxins, while in cell-free extracts degradation was inhibited by SKF 525-A, metyrapone and cytochrome c but not by KCN. In cell-free extracts, aflatoxin degradation was enhanced by NADPH and NaIO4. The results suggest the involvement of cytochrome P-450 monooxygenases in the aflatoxin degradative activity of A. flavus.     

Influence of stent height upon stresses on the cusps of closed bioprosthetic valves

A finite element model of a bioprosthetic heart valve was developed to determine the influence of the stent height on leaflet stresses under various pressure loading conditions after valve closure. A nonlinear solution was used to obtain the stresses in the leaflets for stent heights of 14.6 mm, 19.0 mm and 22.0 mm respectively. The basic assumptions included an elliptic-paraboloid for a relaxed leaflet shape, a rigid stent, isotropic leaflet material property with a Poisson's ratio of 0.45, a uniform leaflet thickness and a stress dependent Young's modulus. The model predicted an increase of stresses on the closed leaflets as the stent height was reduced. This observation appears to mitigate, to some extent, the hemodynamic benefits thought to accompany the reduction of stent height of bioprosthetic valves.     

Persistent infection of K562 cells by encephalomyocarditis virus.

Infection of human erythroleukemic K562 cells by encephalomyocarditis virus readily resulted in establishment of persistently infected cultures. In contrast to the usual typical lytic infection by encephalomyocarditis virus, in which trypan blue staining of cells reaches close to 100% by about 15 h postinfection, K562 cell cultures required 3 to 4 days postinfection to reach a maximum of about 80 to 90% cell staining. The proportion of K562 cells taking up stain gradually decreased to about 10% of those present by about 13 days postinfection; during this time, virus yield per day measured by either plaque or hemagglutination titration fell about 10-fold. The decrease in percent staining was followed by waves of increased staining accompanied by increased virus production. Virus-producing cultures were maintained for over 3 months. Evolution of both virus and cells accompanied establishment of persistence in that plaque size changed from about 7 mm in diameter for the original virus to less than 1.5 mm by day 20 postinfection and most of the cells cloned from persistently infected cultures were resistant to superinfection with the original virus. Resistance was due, at least in part, to reduced virus attachment in that binding of 3H-labeled virus to cloned resistant cells was about 2% of that to uninfected cells.