In vitro resistance to human platelet microbicidal protein among urethral staphylococcal and enterococcal isolates with its correlation with prostatitis.

The study was carried out to test the in vitro activity of human platelet microbicidal protein (hPMP) on most commonly isolated urethral pathogens and compare the same with clinical isolates from cases of chronic prostatitis (CP). Urethral isolates of Staphylococcus aureus (n=19), coagulase negative staphylococci (n=40) and Enterococcus faecalis (n=16) from patients with or without CP were tested. The hPMP susceptibility of bacterial strains was determined by exposing bacterial cells to serial dilutions of hPMP. A significantly higher proportion of CP-strains of coagulase negative staphylococci (91.3% vs 5.88%) was resistant to hPMP than was that of non-CP strains (P S.aureus studied, 77.8% were considered resistant to the bactericidal action of hPMP. All nine CP-strains of E.faecalis were highly resistant to hPMP. Most non-CP urethral isolates of S.aureus, coagulase negative staphylococci and E.faecalis were susceptible to the bactericidal action of hPMP, while CP isolates of all species were significantly more resistant to hPMP. Data from the present study may have significant implications in understanding the pathogenesis of CP.

Theophylline Increases the Uptake of Radioiodine by Mouse Thyroid

Diagnostic and therapeutic use of radioiodine in the management of thyroid disorders depends on the ability of thyroid cells to concentrate radioiodine, a process that is regulated by the intracellular increase in cAMP. We hypothesized that theophylline, a drug known to increase intracellular cAMP via inhibition of phosphodiesterase, could increase thyroidal radioiodine uptake. We tested this effect in vivo, using C57BL/6j mice, and in vitro, using Fisher rat thyroid (FRTL-5) cells. One mouse received 2.5mg theophylline i.p., whereas a control mouse received only saline. Twenty-hours after theophylline, mice were injected with 10mu Ci Na(125)I in 0.1 mL saline through the tail vein. Mean thyroidal (125)I activity was 3.3-fold higher in theophylline-treated mice than in their respective controls. Radioiodine uptake and intracellular cAMP production of FRTL-5 cells were increased by a relatively low concentration of theophylline (1mu M). Intracellular cAMP increased up to 30 min and then declined in response to 1mu M theophylline. Sera from theophylline-treated mice stimulated (125)I uptake and intracellular cAMP production by FRTL-5 cells. These findings show that theophylline can enhance radioiodine uptake by thyrocytes in vivo and in vitro. The in vitro effects of theophylline on both radioiodine uptake and cAMP production in a dose-dependent manner are consistent with an action mediated by phosphodiesterase inhibition.

Transdifferentiation of Cultured Bovine Lens Epithelial Cells into Myofibroblast-like Cells by Serum Modulation

An after-cataract is caused by the proliferation of residual cells over the equator of the lens. These cells subsequently migrate to the posterior lens capsule, where they undergo aberrant differentiation into fiber-like cells or transdifferentiation into fibroblast-like cells. To study the precise molecular mechanisms of transdifferentiation, an attempt was made to establish an in vitro system, in which the lens epithelial cells (LECs) of the pre-equatorial zone could be transdifferentiated into fibroblast-like cells. The required conditions for culturing the LECs were identified as consisting of four phases; intact bovine explants, explant-cultured, serum-modulated and additionally modulated LECs. The LECs of each phase were compared by examining changes in the expression of the epithelial-mesenchymal transition (EMT) -related genes and changes in cellular morphology and adhesion. The explants that were cultured in a medium containing 10% fetal bovine serum (FBS) for 2 weeks, showed changes in the expression of the EMT-related genes, although the other explant-cultured cells maintained an epithelial morphology. To introduce a transition into mesenchymal cells, the explant cultures were subcultured in a medium containing 20% FBS for six passages. These cells displayed an elongated morphology and were able to grow and migrate in a similar way to fibroblast cells. The expression of the EMT-related genes, such as, extracellular matrix proteins and integrins, was altered. This was similar to the alteration of the 3-dimensional collagen gels model previously reported. During a further process of EMT by additional serum modulation, the inhibitory effect of disintegrin on cell adhesion was gradually decreased, integrin expression was differentially regulated and alpha-smooth muscle actin was post-translationally modified from the point of passage number six. Overall, it can be concluded that terminal transdifferentiation accompanies changes in the cytoskeletal proteins and cell surface molecules. These are modulated in systematic patterns of post-transcriptional and post-translational regulation and patterns of gene regulation, by the synergic effects of several transforming factors contained in serum. Therefore, posterior capsular opacification may also be accompanied by this molecular mechanism.

The Role of Nitric Oxide in Ocular Surface Cells

The role of nitric oxide (NO) in the ocular surface remains unknown. We investigated the conditions leading to an increase of NO generation in tear and the main sources of NO in ocular surface tissue. We evaluated the dual action (cell survival or cell death) of NO depending on its amount. We measured the concentration of nitrite plus nitrate in the tears of ocular surface diseases and examined the main source of nitric oxide synthase (NOS). When cultured human corneal fibroblast were treated with NO producing donor with or without serum, the viabilities of cells was studied. We found that the main sources of NO in ocular surface tissue were corneal epithelium, fibroblast, endothelium, and inflammatory cells. Three forms of NOS (eNOS, bNOS, and iNOS) were expressed in experimentally induced inflammation. In the fibroblast culture system, the NO donor (SNAP, S-nitroso-N-acetyl-D, L-penicillamine) prevented the death of corneal fibroblast cells caused by serum deprivation in a dose dependent manner up to 500 micrometer SNAP, but a higher dose decreased cell viability. This study suggested that NO might act as a doubleedged sword in ocular surface diseases depending on the degree of inflammation related with NO concentration.