Prevention of ultraviolet radiation-induced suppression of accessory cell function of Langerhans cells by Aloe vera gel components

The active components of Aloe vera gel that can prevent ultraviolet B (UVB)-induced suppression of accessory cell function of Langerhans cells (LC) were purified by activity-guided sequential fractionation followed by in vitro functional assay. The functional assay was based on the fact that exposure of freshly isolated murine epidermal cells (EC) to UVB radiation resulted in impairment of accessory cell function of LC, as measured by their ability to support anti-CD3 monoclonal antibody (mAb)-primed T-cell mitogenesis. This UVB-suppressed LC accessory cell function was prevented by addition of partially purified Aloe gel components to cultures of UVB-irradiated EC. The Aloe gel components appeared to prevent events occurring within the first 24 h after UVB irradiation that lead to the impairment of accessory cell function. The Aloe gel components did not cause proliferation of anti-CD3 mAb-primed T-cells, nor did induce proliferation of normal EC. The activity-guided final purification of Aloe gel components resulted in the isolation of two components. Both of the components were small molecular weight (MW) substances with an apparent MW of less than 1,000 Da but different from each other in net charge characteristics at pH 7.4. These results suggest that Aloe vera gel contains at least two small molecular weight immunomodulators that may prevent UVB-induced immune suppression in the skin.     

Generation of cells with Hodgkin's and Reed-Sternberg phenotype through downregulation of CD99 (Mic2)

Despite the fact that Hodgkin's and Reed-Sternberg (H-RS) cells are morphological hallmarks of Hodgkin's disease (HD), the nature of H-RS cells still remains to be resolved. Here we report that downregulation of CD99 (Mic2) leads to the generation of cells with an H-RS phenotype. IM9 and BJAB B-cell lines that were transfected with an antisense CD99 expression construct showed the morphological and immunological characteristics of H-RS cells such as multinuclearity, expression of CD15, decreased expression of major histocompatibility complex (MHC) class I and CD45RB, and deregulated secretion of cytokines. The reduced expression of CD99 was also confirmed in H-RS cells of patient's lymph nodes and three HD-derived cell lines, L428, KM-H2, and HDLM-2. Moreover, features characteristic of H-RS cells were completely abolished by forced expression of CD99 and by a constitutively active form of Rac, which functions downstream of CD99. We suggest that CD99 molecules play a crucial role in regulating functions and morphology of cells through a Rac-Rho signaling pathway and that the loss of CD99 expression is a significant molecular event to generate H-RS cells.     

Desulfurization of diesel oils by a newly isolated dibenzothiophene-degrading Nocardia sp. strain CYKS2

A dibenzothiophene (DBT)-degrading bacterial strain was isolated from dyeing industry wastewater and identified as Nocardia sp. CYKS2. The newly isolated bacterial strain Nocardia sp. CYKS2 was able to convert DBT to 2-hydroxybiphenyl (2-HBP) as the dead-end metabolite through a sulfur-specific pathway. Other organic sulfur compounds, such as thiophene derivatives, thiazole derivatives, sulfides, and disulfides were also desulfurized by Nocardia sp. CYKS2. In batch culture, 0.2 mM DBT was completely desulfurized in 60 h. After DBT was depleted, neither cell growth nor 2-HBP production was observed. When a model oil which DBT was dissolved in hexadecane was treated with growing cells, DBT was desulfurized from 10 mM to about 2 mM in 80 h. In this case, desulfurization rate was 0.279 mg-sulfur/(L-dispersion.h), which was about 2.5 times higher than that in the previous case of batch culture. When diesel oil was treated, the sulfur content decreased from 0.3 to 0.24 wt % in 48 h. A volumetric phase ratio of oil to water was 1/10 in this case. The sulfur decreased from 0.3 to 0.2 wt % in 48 h, when the volumetric phase ratio was 1/20. The desulfurization rates were 0.909 and 0.992 mg-sulfur/(L-dispersion.h), respectively.     

A position based kinematic method for the analysis of human gait

Human joint motion can be kinematically described in three planes, typically the frontal, sagittal, and transverse, and related to experimentally measured data. The selection of reference systems is a prerequisite for accurate kinematic analysis and resulting development of the equations of motion. Moreover, the development of analysis techniques for the minimization of errors, due to skin movement or body deformation, during experiments involving human locomotion is a critically important step, without which accurate results in this type of experiment are an impossibility. The traditional kinematic analysis method is the Angular-based method (ABM), which utilizes the Euler angle or the Bryant angle. However, this analysis method tends to increase cumulative errors due to skin movement. Therefore, the objective of this study was to propose a new kinematic analysis method, Position-based method (PBM), which directly applies position displacement data to represent locomotion. The PBM presented here was designed to minimize cumulative errors via considerations of angle changes and translational motion between markers occurring due to skin movements. In order to verify the efficacy and accuracy of the developed PBM, the mean value of joint dislocation at the knee during one gait cycle and the pattern of three dimensional translation motion of the tibiofemoral joint at the knee, in both flexion and extension, were accessed via ABM and via new method, PBM, with a Local Reference system (LRS) and Segmental Reference system (SRS), and then the data were compared between the two techniques. Our results indicate that the proposed PBM resulted in improved accuracy in terms of motion analysis, as compared to ABM, with the LRS and SRS.     

Polycrystalline silicon film deposited by ICP-CVD

We studied the deposition of polycrystalline silicon (poly-Si) using SiH₄/SiH₂Cl₂/H₂ mixtures by inductively coupled plasma chemical vapor deposition. The deposition rate and crystalline quality were improved by increasing RF power. The poly-Si film deposited with the [SiH₂Cl₂]/[SiH₄] ratio of 2 and the RF power of 1500 W exhibited the deposition rate of 4.2 Å/s, the polycrystalline volume fraction of 88%, the Raman FWHM of 7 cm⁻¹, and the TEM grain size of 1200 Å. The solar cell made of this material exhibited a conversion efficiency of 3.14%.     

The least-squares meshfree method for solving linear elastic problems

 A meshfree method based on the first-order least-squares formulation for linear elasticity is presented. In the authors' previous work, the least-squares meshfree method has been shown to be highly robust to integration errors with the numerical examples of Poisson equation. In the present work, conventional formulation and compatibility-imposed formulation for linear elastic problems are studied on the convergence behavior of the solution and the robustness to the inaccurate integration using simply constructed background cells. In the least-squares formulation, both primal and dual variables can be approximated by the same function space. This can lead to higher rate of convergence for dual variables than Galerkin formulation. In general, the incompressible locking can be alleviated using mixed formulations. However, in meshfree framework these approaches involve an additional use of background grids to implement lower approximation space for dual variables. This difficulty is avoided in the present method and numerical examples show the uniform convergence performance in the incompressible limit. Therefore the present method has little burden of the requirement of background cells for the purposes of integration and alleviating the incompressible locking. Received: 16 December 2001 / Accepted: 4 November 2002     

The effect of low-and high-dose adjunctive mitomycin C in trabeculectomy

Selenium is a powerful antioxidant regulating the activity of the glutathione peroxidase enzymes, which catalyse the detoxification of hydrogen peroxide and organic hydroperoxides. Selenium deficiency has been implicated in the aetiopathogeny of Keshan disease, an endemic cardiomyopathy observed in China, and in other cases of congestive cardiomyopathy in subjects on artificial nutrition. However, the evidence from case-control and prospective studies for an association between low selenium status and cardiovascular diseases remains controversial. Mechanisms whereby selenium protects against such diseases include increased resistance of low-density lipoproteins against oxidative modification, modulation of prostaglandin synthesis and platelet aggregation, and protection against toxic heavy metals. The therapeutic benefit of selenium administration in the prevention and treatment of cardiovascular diseases still remains insufficiently documented.     

Posthemorrhagic antipyresis: what stage of fever genesis is affected?

This study was conducted to determine the time course of metabolic changes associated with a switch from a high-fat to a low-fat diet in rats. Adult rats, maintained on a high-fat diet (42% of energy from fat) for 4-5 weeks were switched to a low-fat diet (11% of energy from fat), and the activities of several liver enzymes were followed. Three different phases could be distinguished. The early phase, complete by 2 days after the switch in diets, included an increase in the activity of glucose 6-phosphate dehydrogenase (pentose phosphate pathway), an increase in pyruvate kinase and pyruvate dehydrogenase activities (terminal end of the glycolytic pathway) and an increase in ATP-citrate lyase and fatty acid synthetase (fatty acid synthesis pathway). The early phase also included a decrease in the activity of phosphoenolpyruvate carboxykinase (PEPCK, gluconeogenesis) and a lower branched-chain amino acid dehydrogenase activity (BCAADH, branched-chain amino acid degradation). The concentration of the allosteric phosphofructokinase regulator, fructose 2,6-bisphosphate (Fru-2,6-P2, glycolysis), decreased during the early phase. An intermediate phase could also be discerned between 3 and 10 days after the switch in diets. In this phase, the decreased Fru-2,6-P2 concentration and the decreased PEPCK and BCAADH activities observed in the early phase were reversed. The late phase occurred 10 days after the dietary switch and was characterized by an increase in the activities of glucokinase (glycolytic pathway) and glycogen phosphorylase (associated with glycogenolysis) and by a decrease in glutamate dehydrogenase, PEPCK and BCAADH activities. These measurements indicate that at least 20 days are required before metabolic changes associated with a switch in diet are complete.