Polymorphonuclear cells (PMNs) contribute to the initiation and progression of the immune response by mediating cytotoxicity, phagocytosis, and cytokine secretion. Because CD44 serves as a cytotoxic-triggering molecule on PMNs, it was hypothesized that it could also trigger cytokine production. In this study, the effect of anti-CD44 antibodies on interleukin-6 (IL-6) production in human PMNs was assessed. By using a reverse transcriptase-polymerase chain reaction, it was shown that PMNs stimulated with a mouse monoclonal or a rabbit polyclonal F(ab)(2) anti-CD44 transcribe IL-6 messenger RNA. A similar effect was obtained when an anti-CD44 antibody was replaced with hyaluronic acid (HA). Kinetic studies showed that anti-CD44 and HA induced IL-6 gene transcription, initiated 3 hours after stimulation, peaked between 12 and 24 hours, and disappeared after 48 hours. Analogous results were achieved when secreted IL-6 protein was measured by enzyme-linked immunosorbent assay in the PMN culture supernatants. To characterize which metabolic pathways regulated CD44-dependent IL-6 production in PMNs, an RNA polymerase inhibitor, actinomycin D, and 2 protein kinase inhibitors, such as genistein and staurosporine, were tested. Actinomycin D and genistein blocked IL-6 production, whereas staurosporine did not, suggesting that CD44-dependent IL-6 production requires gene transcription and tyrosine kinase activity. Furthermore, the relationship between CD44 and cytokines that affect PMN function, including interferon gamma (IFNgamma) and IL-2, was investigated. Without CD44 cross-linking, IFNgamma did not trigger IL-6 production. However, on CD44 cross-linking, IFNgamma produced a strong synergistic effect on IL-6 syntheses in human PMNs. (Blood. 2001;97:3621-3627)

Cytokines, and interleukin-6 in particular, are inflammatory peptide mediators that are extensively studied as regulators of bone tissue homeostasis. They seem to be involved in osteoclast activation and bone resorption and probably play a role in osseointegrated implant rejection. In this study we investigate the ability of titanium implants to cause an imbalance in the homeostatic equilibrium of cytokines using the peritoneal cavity of DB-A2 mice as a model. The inflammatory response was evaluated as a messenger ribonucleic acid expression determined by the semiquantitative reverse transcriptase-polymerase chain reaction technique in peritoneal macrophages from titanium-implanted mice. Interleukin-6 release was detected by a specific quantitative enzyme-linked immunosorbent assay. Our results have shown that titanium implants do not significantly stimulate the proinflammatory cytokine system compared to the control group. The enzyme-linked immunosorbent assay test confirms, after a peak in secretion at day 1 compared with basal levels, a clear decrease in interleukin-6 at basal levels on following control at 6 and 9 days after implantation. The study of the interaction between implanted biomaterials and inflammatory mediators seems to be very promising.Perhaps a better understanding of the mechanisms of bone resorption could lead to finding a new clinical solution for patients with osseointegrated implant rejection.

Gynecomastia is a benign pathology due to the increased volume of the mammary glands. The various etiological factors lead to an imbalanced estrogen/androgen ratio or to a greater local receptivity to the former with consequent hypertrophy of the mammary stromal gland components. Although the majority of cases are benign and/or transient, gynecomastia must be carefully examined using thorough anamnesis, hormone assays and instrumental tests in order to exclude local or further removed pathology. At present, medical or surgical therapy is reserved for those cases in which this condition is painful and/or psychologically damaging. In this study, following a review of the literature, the Authors focus on the etiological, diagnostic and therapeutic aspects of gynecomastia and illustrate the cases they have observed.

The aim of the study was to define a therapy to be combined with an immunosuppressive drug such as cyclosporin A, in order to partially reduce the nephrotoxic and hepatotoxic effects in the treated rats. Two drugs were considered: enalapril, which is an inhibitor of the angiotensin-converting enzyme, and spironolactone, which is an antagonist of aldosterone. These two drugs interrupt the renin-angiotensinogen-angiotensin chain after this has been activated by cyclosporin A, preventing peripheral vasoconstriction and more specifically the constriction of both glomerular arterioles and hepatic vessels from occurring, thus diminishing the cyclosporin A toxicity in both liver and kidney.

An experimental study on rats in order to discovery any possible interaction between Ciclosporin (CyA) and H2-receptor antagonists has been carried out. The results obtained demonstrated that the serum levels of CyA were higher in rats treated with CyA and Cimetidine or Ranitidine, but not Famotidine. It is probable that the increase of ciclosporinaemia is the consequence of an increased hepatotoxicity due to administration of Cya in association with Cimetidine or Ranitidine.

The H2-receptor antagonists seem to be effective in prevention and treatment of stress ulcer in transplant recipients. In a previous study on rats, an increase was observed in cyclosporinaemia and hepatotoxicity after administration of cimetidine or ranitidine in association with cyclosporin A (CyA). On the contrary, famotidine does not influence the blood CyA levels. The aim of the study was to detect the possible synergistic nephro- and hepatotoxicity of nizatidine administered in association with CyA, assaying the serum creatinine, the ALT and AST levels, and histological features of thirty young male Sprague-Dawley rats, divided into 6 groups of five animals each. After 10 days, all the rats were sacrificed, their blood was collected to assay serum creatinine, ALT, AST and serum CyA levels: kidneys and livers were processed for light microscopy. The results obtained demonstrated that, while the level of creatinine was normal in each group, the average level of transaminase and the serum levels of CyA were significantly higher in the animals receiving the association of CyA and nizatidine. Furthermore, this group demonstrated a mild infiltrate of the liver characterized in some cases with eosinophilic polymorphonuclear cells. In light of the results obtained, it is probable that the increase of cyclosporinaemia is the consequence of an enhanced hepatotoxicity due to administration of CyA in association with nizatidine.

H2-receptor antagonists, such as cimetidine (C), ranitidine (R) and famotidine (F) seem to be effective in the prevention and treatment of stress ulcer in transplant recipients receiving cyclosporin A (CyA). The aim of this study was to detect the possible synergistic nephro- and hepato-toxicity of these drugs, assaying the serum creatinine (SC), ALT, AST levels, and the histological features of 45 young male Sprague-Dawley rats, divided into nine groups of five rats each. After 10 days of treatment the results showed: (i) serum CyA levels were increased in the group receiving daily CyA (5 mg/kg) + R(5 mg/kg) (2430 +/- 403 ng/ml; p less than 0.05 vs. controls) and in the group receiving daily CyA (5 mg/kg) +/- C (10 mg/kg) (2440 +/- 265 ng/ml; p less than 0.01 vs. controls); (ii) ALT and AST levels were increased in this latter group (ALT 223 +/- 133 UL, AST 114.67 +/- 39 UL; p less than 0.01 vs. controls); (iii) SC levels were normal; and (iv) steatosis of the liver was observed in these two groups. These findings suggest that C and R, but not F, may inhibit the hepatic cytochromes P-450 which are involved in the oxidative metabolism of the drugs. Furthermore, the high serum CyA levels seem to play a major role in the appearance of biochemical and histological damage to the liver.

The H2 receptor antagonists (H2ra) such as cimetidine (C), ranitidine (R), and famotidine (F) seem to be effective in the prevention and treatment of stress ulcer in transplant recipients receiving cyclosporin A (CyA). A major problem in the management of these patients is to define the possible influence of H2ra on CyA metabolism and the possible synergistic nephro- and hepatotoxicity of these drugs, when co-administered (1). The aim of this research was to study the possible interaction between CyA, on one hand, and C, R, and F, on the other hand by evaluating the serum creatinine (SC), the serum alanine aminotransferase (ALT), the serum aspartate aminotransferase (AST) levels in experimental rats, in order to determine whether H2ra may be used with CyA without risk. Histological observations of the liver and kidneys of all rats studied were performed at the end of the experimental period.