The effect of T-2 toxin on IL-1beta and IL-6 secretion in human fetal chondrocytes

The effects of T-2 toxin on IL-1beta and IL-6 secretion in human fetal chondrocytes in vitro were investigated. The evaluation is realised on primary monolayer culture of human fetal epiphyseal chondrocytes with or without PMA stimulation. The levels of supernatant IL-1beta and IL-6 were analyzed by ELISA. As compared with their respective controls, we observed a significant increase of IL-Ibeta and IL-6 in supernatants of chondrocytes cultivated for 24 h with T-2 at 8 ng/ml after PMA stimulation; in the absence of PMA, IL-Ibeta was increased alone after 48 h. The results demonstrated that T-2 toxin could superinduce IL-1beta and IL-6 secretion in chondrocytes. All these data suggested that superinduction of cytokines might be one of the key mechanisms of chondrocyte injuries by T-2 toxin.

Modulation of interleukin-1 secretion by immunosuppressive drugs, alone and in combination

This study evaluates the ability of the immunosuppressive drugs dexamethasone, cyclosporine, FK506 and rapamycin, alone and in combination to suppress interleukin-1 beta (IL-1 beta) secretion in vitro by THP-1 cells when stimulated by lipopolysaccharide. All four drugs, when added to cell culture medium at therapeutic concentrations, significantly decrease secretion of the monokine to well below control levels. However, only dexamethasone completely suppresses IL-1 beta secretion in a dose-dependent fashion. Cyclosporine, FK506 and rapamycin only partially suppress secretion of IL-1 beta at concentrations within their therapeutic ranges and increasing concentrations of the drugs do not result in further suppression of secretion. Likewise, the combination of any two of these three drugs does not provide any additional suppressive effect. Dexamethasone, however, when added in increasing concentrations in combination with any of the other drugs, results in further suppression of IL-1 secretion in a dose-dependent fashion. These data suggest that cyclosporine, FK506 and rapamycin all share a common effect on the production of IL-1 beta, different from that of dexamethasone.

Raman or fluorescent scattering by active molecules or ions embedded in a single-mode optical fiber

By considering active molecules or ions as a collection of induced oscillating dipoles, we treat the problem of Raman or fluorescent scattering by the active molecules or ions embedded in a single-mode optical fiber theoretically. The analytical expressions and the numerical results for the scattering coefficients and the even-odd mode conversion coefficients of the guided modes are given, based on the method of dyadic Green's functions and on the expansions of the modal fields in terms of the vector cylindrical wave functions. We expect to incorporate the treatments into the analysis of a rare-earth-doped fiber amplifier or a fiber Raman amplifier.

Vitamin A, Vitamin E or beta-carotene status and hepatitis B-related hepatocellular carcinoma

A case-control study was carried out in 59 patients with newly diagnosed hepatocellular carcinoma and 101 control subjects, who were all male hepatitis B carriers. The odds ratios of hepatocellular carcinoma occurring among hepatitis B carriers in the lowest quartile and those highest quartile of dietary and serum status were 5.3 (1.9 to 15.0) and 86.9 (20.0 to 377.2), respectively. The odds ratios for hepatitis B carriers in the lowest quartile and those in the highest quartile of dietary and serum beta-carotene status were 1.7 (0.7 to 4.1) and 5.0 (1.9 to 13.2). Vitamin E status did not differ in case patients and control subjects. Low education level, heavy consumption of alcohol, and smoking status were also associated with increased odds of hepatocellular carcinoma. Serum retinol, positively associated with dietary retinol, demonstrated an independent effect on hepatocellular carcinoma. This effect may reflect changes in the physiologic condition of the patients at the time of entering the hospital.

Radiation loss in bent step-index slab waveguides

Based on the exact scalar wave equations of bent slab waveguides, locally leaky-mode attenuation constants for both TE and TM modes are derived by using the WKB tunneling theory. Changes in propagation constant due to waveguide bending are considered in our calculation. Under some assumptions, our results are found to be identical to other results obtained using entirely different methods.

Cloning and expression of a smooth muscle caldesmon

Caldesmon is a smooth muscle and nonmuscle regulatory protein that interacts with actin, myosin, tropomyosin, and calmodulin. Two overlapping clones, isolated from a chicken oviduct cDNA plasmid library and a chicken gizzard cDNA lambda NM1149 library, were used to generate a 4108-base pair sequence coding for one caldesmon. Expression of the coding sequence confirms this is one of the large smooth muscle caldesmons. The deduced protein molecular weight is 86.974, significantly less than the molecular weights estimated by sodium dodecyl sulfate gel electrophoresis. The protein has a high content of Gly, Lys, Arg, and Ala; there are two cysteine residues, one at either end of the molecule. Comparison with the Protein Identification Resource database demonstrates a similarity with a tropomyosin binding domain of troponin T, but none with any calmodulin or actin binding proteins. The center of the protein has an 8-fold repeat of a 13 amino acid sequence whose general motif is -Glu3-(Lys/Arg)2-Ala2-Glu2-(Lys/Arg)1-X-(Lys/Arg)1-Ala1-, where X is Glu, Gln, or Ala. Comparison with peptide sequences from a chymotryptic fragment that binds actin and calmodulin places this domain on the C terminus of caldesmon adjacent to the troponin T similarity. A tentative map of the major binding domains is proposed on the basis of available data.