Human recombinant interleukin 1-mediated suppression of glycosaminoglycan synthesis in cultured rat costal chondrocytes

Effects of human recombinant interleukin 1 (IL-1) on the synthesis of glycosaminoglycan were examined with cultured rat costal chondrocytes. Incorporation of [35S]sulfate into glycosaminoglycan was strikingly diminished by the addition of IL-1 in a dose- and time- dependent manner. When the cells were cultured with 340 micrograms/ml of IL-1 for 72 hr, the synthesis of glycosaminoglycan was inhibited to 10% of the control. On the other hand, IL-1 had no effect on the morphology and proliferation of the chondrocytes. The suppression of glycosaminoglycan synthesis remained unchanged after the addition of indomethacin, indicating that the effect of IL-1 is independent of the enhanced synthesis of prostaglandins.     

Effect of muscle mass on V(O(2)) kinetics at the onset of work.

The dependence of O(2) uptake (V(O(2))) kinetics on the muscle mass recruited under conditions when fiber and muscle recruitment patterns are similar following the onset of exercise has not been determined. We developed a motorized cycle ergometer that facilitated one-leg (1L) cycling in which the electromyographic (EMG) profile of the active muscles was not discernibly altered from that during two-leg (2L) cycling. Six subjects performed 1L and 2L exercise transitions from unloaded cycling to moderate [VT) exercise. The 1L condition yielded kinetics that was unchanged from the 2L condition [the phase 2 time constants (tau(1), in s) for 0.05; for >VT: 1L = 26.8 +/- 12.0; 2L = 27.8 +/- 16.1, P > 0.05]. The overall V(O(2)) kinetics (mean response time) was not significantly different for the two exercise conditions. However, the gain of the fast component (the amplitude/work rate) during the 1L exercise was significantly higher than that for the 2L exercise for both moderate and heavy work rates. The slow-component responses evident for heavy exercise were temporally and quantitatively unaffected by the 1L condition. These data demonstrate that, when leg muscle recruitment patterns are unchanged as assessed by EMG analysis, on-transient V(O(2)) kinetics for both moderate and heavy exercise are not dependent on the muscle mass recruited.     

Impact of difructose anhydride III,raffinose, and fructooligosaccharides on energy intake,gut hormones,and cecal fermentation in rats fed a high-fat and high-sucrose diet

We investigated the effects of dietary supplementation of difructose anhydride III (DFA III), raffinose (Raf), and fructooligosaccharides (FOS) on diet-induced obesity development. Male rats were fed normal or high-fat and high-sucrose (HFS) diet, with or without supplementing (3%) DFA III, Raf, or FOS, for 8 or 5 weeks. Supplementing DFA III to the HFS diet decreased energy intake compared to the non-supplemented HFS diet. Accordingly, body weight gain and fat accumulation reduced in DFA III-fed rats. Cecal acetate production and plasma glucagon-like peptide-1 (GLP-1) and peptide-YY (PYY) were elevated in DFA III-fed rats, while Raf and FOS partially affected these parameters. These results demonstrate that DFA III has suppressive effect on excessive energy intake driven by the palatable obesogenic diet, possibly due to combined effects of increased anorexigenic factors such as cecal acetate production and GLP-1/PYY secretion.     

Electron microscopic observations on the cholesterol distributed in the epithelial cells of the gallbladder.

Epithelial cells of eight human gallbladders with cholesterosis were examined. In the supranuclear portion of the epithelial cells of one case, many spicular, circular and plate-like crystalline structures are present. Spicular and circular structures have not a limiting membrane, but plate-like structures are apparently bounded by a limiting membrane that clearly shows trilamellar structure. After digitonin treatment, the spicular and circular crystalline structures become denser. On the other hand, the plate-like structures do not become denser by digitonization. In the epithelial cells that contain no crystalline structure, there also occur many reaction precipitates after digitonization. These findings may suggest that free cholesterol is highly present in the epithelial cells of gallbladder with cholesterosis and that it, in some case, precipitates in the form of spicular or circular structure for the rapid fixation process.     

Breath-by-breath gas exchange kinetics during constant-load work

In order to study respiratory transients during exercise, we examined breath-by-breath gas exchange kinetics during constant-load work. Five male subjects performed cycle ergometer tests which 6 min of constant-load work (150, 200, 250W) followed 50W base-line work. VCO2 and VO2 measured at the mouth ((VCO2)E, (VO2)E) and estimated at the alveolar level ((VCO2)A, (VO2)A) were computed breath-by-breath. The kinetic parameter (time constant) of first- and second-order exponential model was estimated using non-linear least-squares method. Our results demonstrated that a relative stability of PETO2, PETCO2, and R at their control values in the first phase. Independent of work intensities, breath-by-breath variation in gas exchange measured at the mouth was larger than those in gas exchange estimated at the alveolar level both at a non-steady state and a steady state. The time constants of (VO2)A and (VO2)E were varied with increase of work load intensity.     

Oxidation of nucleosides and nucleotides by peroxosulfate ions

Treatment of 5-methylpyrimidine nucleosides and nucleotides with sodium peroxodisulfate in sodium phosphate buffer solution at pH 7.0 at 75 degrees C resulted in the selective oxidation of the methyl group. On the other hand, oxidation of thymidine by potassium peroxomonosulfate gave thymidine glycols.     

Ability of various oral bacteria to bind human plasma fibronectin

The present study describes the ability of various oral bacteria to bind human plasma fibronectin (PFN). Avid binding of 125I-PFN was found for Streptococcus mutans (serotypes a to h), Streptococcus sanguis, group A Streptococcus pyogenes and Staphylococcus aureus, while other gram-positive bacterial species tested demonstrated only weak or negligible PFN binding ability. Two gram-negative bacterial species, Bacteroides gingivalis and Escherichia coli, did not significantly bind PFN. 125I-PFN binding to S. mutans 6715 cells was decreased by pretreatment with unlabeled PFN, and the radiolabeled PFN bound to the cell surface was released on addition of unlabeled PFN. Strong inhibition of 125I-PFN binding to S. mutans 6715 cells was obtained by protease pretreatment, while partial inhibition was also observed following treatment with acid, alkali, lipase, and monoclonal anti-polyglycerophosphate. These results suggest that PFN binding to S. mutans cells is reversible and that PFN receptors on the cell surface appear to be heat-stable multiple proteins.     

Partial characterization of thymocyte-activating factor derived from MDP-stimulated guinea pig fibroblasts

The activity of fibroblast-derived thymocyte activating factor (FTAF) of the guinea pig was measured, and the factor was partially characterized. The FTAF activity was heat labile, and destroyed by treatment with trypsin, chymotrypsin, and Streptomyces griseus protease, suggesting the protein nature of FTAF. FTAF bound to DEAE-Sepharose CL-6B in Tris-HCl buffer at pH 8.0, and was eluted with 0.1-0.2 M NaCl. FTAF was absorbed with Blue Sepharose CL-6B. The factor bound to a hydroxylapatite column in 10 mM phosphate buffer and was eluted in two major fractions, one fraction with 40 mM phosphate buffer, the other with 70-110 mM phosphate buffer. Finally, FTAF did not have as much effect on the proliferation of lymph node T cells as T-cell-activating monokines which exhibited marked stimulating effects on both T lymphocytes and thymocytes.