BCG-activated NK cells regulate the antibody response to SRBC and restore immune reactivity to PPD in BCG-infected mice.

C57B1/6 mice show a significant increase in the number of natural killer (NK) cells in the peritoneal cavity, four days after intraperitoneal infection with Mycobacterium bovis strain BCG. Cell transfer experiments demonstrated that BCG-induced NK cells are able to depress the induction of antibody response to an unrelated antigen (i.e., sheep red blood cells) in recipient mice. The involvement of macrophages, B and T cells in the phenomenon was ruled out by using different purification steps. In addition, BCG-induced NK cells were shown to be able of partially restoring the DTH response to PPD in recipient mice that were anergic to the latter antigen as a consequence of intravenous infection with large doses of BCG.

Potentiometric alternating biosensing system for in continuum toxicity tests on cell population.

In this paper, we investigate the possibility to monitor, in continuum, changes of cellular metabolism. Examples of this feature are shown: metabolic changes due to drugs administration are evaluated as a decrease of extracellular acidification rate on CHO-K1 and HeLa cells. Parallel experiments with a standard test were performed to validate the results obtained with the biosensor.

Depression of the immune responsiveness in mice treated with thioacetamide after antigen exposure.

The effects of the weak carcinogen thioacetamide (TAA) on the mouse immune response have been investigated. TAA administration up to 1 day after antigen priming markedly suppressed the antibody response to both T-dependent (sheep erythrocytes) and T-independent (trinitrophenyl-Ficoll) antigens; the compound was ineffective when given 3 or 4 days after immunization. A significant suppression of the in vitro lymphoproliferative response to the B-cell mitogen S. aureus Cowan I was evident from 3 to 48 h after TAA treatment. On the other hand, cell-mediated immune response to oxazolone was suppressed by TAA at each time tested, including that of challenge. The in vitro lymphoproliferative response to concanavalin A was decreased 12 h after TAA administration only, when adenosine deaminase activity within lymphocytes was increased. Furthermore, TAA is endowed with anti-inflammatory activity, as shown by the decreased footpad swelling and by evaluation of the inflammatory cell infiltration upon carrageenan injection. Taken together, these findings suggest selective TAA interaction with multiple targets within the immune system, including B- and T-lymphocytes, while non-specific cytotoxicity can be reasonably ruled out, since hematological determinations and phenotypic analysis of spleen lymphocyte subsets showed no relevant changes.

B-cell-mediated depression of the granulomatous response to BCG in mice.

The depression of the granulomatous response to Mycobacterium bovis strain BCG in mice infected intravenously with 2 x 10(7) CFU of the microorganism turned out to be mediated by various types of cells arising at different times after infection. Anti-PPD B lymphocytes were found to play a major role at Day 1 after infection and to be no longer effective 4 days later. At this time the depression was mediated by anti-idiotype B lymphocytes, whereas T lymphocytes proved to be involved in later phases of the infectious process. These results show that B lymphocytes may be of critical importance in the regulation of cell-mediated immune reactions to this facultative intracellular parasite.

Isolation of Chlamydia trachomatis during IVF-ET.

The Authors isolated Chlamydia Trachomatis from the granulosa and from the spermatozoa of an infertile couple taking part in the IVF-ET program at the Department of Obstetrics and Gynaecology of the University of Pisa.

The penetration of roxithromycin into human skin.

The skin penetration of roxithromycin was studied in 27 surgical patients treated with 300 mg orally followed by three oral doses of 150 mg 12-hourly. Peak plasma and skin concentrations of 7.9 +/- 1.2 mg/l and 31.3 +/- 3.7 mg/kg occurred 2.5 and 4 h after last dosing respectively. The plasma and skin half-lives were 7.7 and 6.0 h, and the mean plasma and skin area under the curve values were 64.3 mg/l.h and 155.3 mg/kg.h. Skin/plasma concentration ratios were 4.9 +/- 0.5, 9.7 +/- 1.2, 7.6 +/- 0.8 and 5.9 +/- 1.1, at 3, 4, 5 and 6 h after last dosing respectively. These results demonstrate that roxithromycin achieves high levels in human skin.

Roxithromycin penetration into gingiva and alveolar bone of odontoiatric patients.

The concentrations of the new macrolide antibiotic roxithromycin in plasma, saliva, gingiva, and alveolar bone were studied in 24 odontoiatric patients treated with a first dose of 300 mg p.o. followed by three maintenance doses of 150 mg p.o., 12-hourly. Samples of blood, saliva, gingiva, and bone were collected at various time points up to 24 h after the last dosing, and the roxithromycin concentration was measured microbiologically, using Bacillus subtilis ATCC 6633 as the reference organism. Pharmacokinetic analysis was performed according to a two-compartment open model with first-order absorption. The plasma, gingiva, and alveolar bone peak concentrations were 6.12 +/- 1.94 mg/l, 6.55 +/- 2.54 mg/kg, and 5.09 +/- 1.60 mg/kg, respectively. Low levels of roxithromycin were detected in saliva (0.67 +/- 0.12 mg/l at the 3rd h). The values of the area under the concentration-time curve for plasma, gingiva, and bone were 59.47 mg/l.h, 51.88 mg/kg.h and 46.80 mg/kg.h, respectively; the half-life values were 7.52 h for plasma and 6.36 and 5.20 h for gingiva and bone, respectively. These results indicate that roxithromycin reaches high levels in periodontal tissues.