In vivo release of cisplatin from a needle-type copolymer formulation implanted in rat kidney

Cisplatin, cis-dichlorodiamine platinum (II), was incorporated in a needle-type copolymer formulation (0.8 mm diameter, 6 mm long) by radiation-induced polymerization. The copolymer used was copoly(diethylene glycol dimethacrylate/polyethylene glycol #600 dimethacrylate, 80/20 vol%). This copolymer, containing 6 mg of cisplatin, was implanted into the kidney of adult male Wistar rats (420 +/- 20 g). A total of 70 d was required for 100% release of cisplatin in vivo. The kidney tissue surrounding the formulation was strongly necrotized by the action of cisplatin. Two layers of necrosis could be distinguished: necrotic tissue surrounding the formulation and necrobiotic tissue surrounding the necrotic tissue. The amount of necrotic tissue changed markedly over time, but no change was apparent in the amount of necrobiotic tissue. The maximal amounts of necrotized tissue were observed 14 d after implantation: 3100 microns and 600 microns thick for the necrotic and necrobiotic tissues, respectively.     

Tumor necrosis factor alpha-induced interleukin-8 production via NF-kappaB and phosphatidylinositol 3-kinase/Akt pathways inhibits cell apoptosis in human hepatocytes

Tumor necrosis factor alpha (TNF-alpha) not only induces apoptotic signals but also causes antiapoptotic and regenerative responses in the liver. However, the molecular mechanism(s) of the latter events remains unclear. In the present study, we examined TNF-alpha-induced genes in Hc human normal (unsensitized) hepatocytes by cDNA microarray analysis. Interleukin-8 (IL-8) induction was the most pronounced of the upregulated genes. The IL-8 protein level was also increased. IL-8 belongs to the ELR-CXC chemokine family and appears to exert mitogenic and antiapoptotic functions in other cell systems. IL-8 expression by TNF-alpha was inhibited when two survival signals, nuclear factor kappaB (NF-kappaB) and phosphatidylinositol 3-kinase (PI3K)/Akt, were inhibited by a mutant form of inhibitor of NF-kappaB (IkappaB); by dominant negative (kinase-dead) Akt; or by treatment with LY 294002, an inhibitor of PI3K. TNF-alpha induced apoptosis in Hc cells that were sensitized by inhibition of NF-kappaB and PI3K activation. IL-8 administration protected mice against concanavalin A-induced hepatitis in vivo. IL-8 also rescued the sensitized Hc cells, at least in part, from TNF-alpha-induced apoptosis in vitro. TNF-alpha inhibited DNA synthesis in unsensitized Hc cells in the absence of serum. Exogenous IL-8 reversed, though anti-IL-8 neutralization antibody enhanced, growth inhibition by TNF-alpha. These results indicate that IL-8, the production of which is stimulated by TNF-alpha, inhibits apoptosis of sensitized hepatocytes and releases normal (unsensitized) hepatocytes from growth inhibition induced by TNF-alpha.     

Optimal degradation rate for collagen chambers used for regeneration of peripheral nerves over long gaps

The experimental study of peripheral nerve regeneration has depended heavily on the use of a nerve chamber in which the stumps of the transected nerve are inserted. A large variety of chamber fillings and chamber types have been used in an effort to induce a higher quality of regeneration across the gap initially separating the two stumps. In this study we studied the morphology of nerves regenerated across a 15 mm gap following implantation of a series of five chambers. The chambers were fabricated from type I collagen and possessed identical pore volume fractions as well as average pore diameters, but differed in cross-link density continuously along the series. The residual mass of the implanted chambers at 9 weeks was observed to increase continuously with increasing cross-link density along the series, indicating a continuous decrease in degradation rate. The quality of regenerated nerves, determined by the number of large diameter fibers (A-fibers) per nerve, the average diameter of all axons and the ratio of area occupied by axons (N-Ratio), was superior at an intermediate level of chamber degradation rate. The maximal quality of peripheral nerve regeneration corresponded to an optimal degradation rate with an estimated chamber half-life of approximately 2-3 weeks following implantation. A speculative mechanistic explanation of the observed optimum focuses on the hypothetical role of cell and cytokine traffic that may take place through holes in the chamber generated by the degradation process. The data show the presence of a hitherto unreported optimal chamber degradation rate that leads to regenerated nerves of maximum quality.     

Is rabbit CLCA1 related to the basolateral Ca2+ -dependent Cl- channel of gastric parietal cells?

An expression of mRNA coding the calcium-activated Cl- channel-1 (CLCA1) in rabbit gastric parietal cells was examined to verify the possibility that the CLCA1 mediates housekeeping Cl- channels in the basolateral membrane. In whole-cell voltage-clamp experiments of rabbit parietal cells, A23187 (2 microM), a Ca2+ ionophore, activated the basolateral Cl- channels. The partial cDNA fragment of rabbit CLCA1 could be amplified from the total RNA of tracheal epithelium. A Northern blot analysis showed that rabbit CLCA1 mRNA of 3.4 kb is highly expressed in the tracheal epithelium, but not in the gastric parietal cells. Even in a more sensitive detection of rabbit CLCA1 mRNA by RT-PCR, no signal could be observed in the gastric parietal cells. These results suggest that the CLCA1 protein may not be a subunit of the housekeeping Ca2+ -dependent Cl- channel in the basolateral membrane of rabbit gastric parietal cells.     

I-J as an Inducible T Cell Receptor for Self

"Jedenfalls, wenn man davorsteht, dann sieht man sich selbstaber eben nicht wie in einem gewöhnlichen Spiegel, versteht sich. Man sieht nicht sein Äusseres, sondern man sieht sein wahres inneres Wesen. so wie es in Wirklichkeit beschaffen ist. Wer da durch will, der muß - um es mal so auszudrücken -in sich selbst hineingehen."
Die undendliche Geschichte, bei Michael Ende, K. Thiehemanns Verlag, Stuttgart, 1979.     

Biological activities of glycoproteins of HVJ (Sendai virus) studied by reconstitution of hybrid envelope and by concanavalin A-mediated binding: a new function of HANA protein and structural requirement of F protein in hemolysis.

When HANA protein of HVJ (Sendai virus) was denatured by dithiothreitol treatment, concanavalin A added to the system or influenza virus hemagglutinin reconstituted with treated HVJ-envelope to form hybrid by SM-2 dialysis method could not replace a role of HANA for hemolysis. Binding of the treated samples to erythrocytes was restored by them, however. Thus, a hypothesis is proposed that intactness of not only F but also HANA protein of HVJ is required for envelope-cell fusion, in other words, HANA protein of HVJ may play some positive role other than binding in the process of the virus-induced hemolysis.     

Clinical and simulator wear study of alumina ceramic THR to 17 years and beyond

Three THAs with cementless monolithic alumina ceramic sockets and cementless Co-alloy stems were retrieved because of aseptic loosening after 17 and 24 years. At revision heads and cups were marked for orientation. Maps were drawn of wear patterns with the use of light microscopy and surveyed by SEM. In a simulator experiment 28-mm-diameter alumina heads and liners were used. The cups were mounted inverted in a hip simulator and run with calf serum as the lubricant. The hip loads were 2 kN maximum and a 1-Hz frequency for 20 million cycles. Wear severity was classified into five grades. In retrieved implants, SEM analysis showed that the main wear zones (MWZ) had Grade 4 wear. The peripheral wear zones (PWZ) showed grain pull-out regions (Grade 5 wear). These corresponded to neck-socket impingement and head-acetabular cup separation. Gray was due to transferred CoCr particles from the stem. In the simulator study, the MWZ had only localized areas of grain pull out surrounded by polished surface regions (Grade 4 wear) at 20 million cycles; stripe wear was not seen. The alumina ceramic bearings proved excellent up to 22 years in simulator studies and clinical studies. However, microseparation kinematics would be necessary in the simulator to duplicate the more peripheral wear zones.     

Mechanism of the formation of megamitochondria by copper-chelating agents. V. Further studies on isolated megamitochondria.

Effect of cuprizone has been studied on some biochemical properties of megamitochondria obtained from the mouse liver. (1) Contents of Ca2+, Mg2+ and Cu2+ in the blood or the liver homogenates were not altered by cuprizone intoxication, whereas those in liver mitochondria were significantly altered: after 3-4 days' intoxication, content of Ca2+ was decreased and was remarkably increased after 14-15 days' intoxication. Content of Mg2+ behaved contrarily. (2) Both cytochrome oxidase and ATPase activities were unchanged in the liver megamitochondria, but monoamine oxidase (MAO) activity was significantly decreased. Value of I50 (50% inhibition) for MAO was determined to be 0.33 mM using the control liver mitochondria. Cuprizone had almost no effect on MAO activity of kidney or heart mitochondria both in vivo and in vitro. (3) The amount of lysolecithin was increased in the liver megamitochondria. These results were discussed in the light of membrane fusion phenomenon which plays a key role in the mechanism of megamitochondrial formation.