Oral Squamous Carcinoma Cells Express B7-H1 and B7-DC Receptors in Vivo.

B7-H1 and B7-DC ligands are members of the B7 family with important regulatory functions in cell-mediated immune response. Both receptors are ligands of the programmed death receptor PD-1. B7-H1 expression has been detected in the majority of human carcinomas in vivo. B7-H1 mediated signals are able to negatively regulate activated T cell functions and survival, and enable tumor cells to overcome host response. The aim of this study was to investigate the expression of B7-H1 and B7-DC proteins in oral squamous cell carcinomas (OSCC) in vivo. Tissues from 15 samples were cryo-sected and following histological routine staining (HE), incubated with antibodies against human B7-H1 and B7-DC. Immuno-staining of pan-cytokeratin was performed to ascertain the epithelial origin of the tissue and CK 19 to demonstrate the proliferating stage. Confocal laser scanning microscopy confirmed the presence of both B7-H1 and B7-DC in all 15 OSCC. The B7-H1 and B7-DC staining was located in areas of the tissue that were identified as cancerous lesions in the previously stained HE sections before. Staining with Pan-CK and CK19 provided evidence for the epithelial origin and the proliferating stage of the tissue. The in vivo expression of the B7-H1 and B7-DC receptors in oral squamous cell carcinomas suggest that general mechanisms for immune evasion of tumors are also found in OSCC.

Environmental factors affecting sexual differentiation in the entomopathogenic nematode Heterorhabditis bacteriophora.

The present study was aimed at determining the influence of various environmental factors on sex differentiation (SD) in the entomopathogenic nematode Heterorhabditis bacteriophora HP88 strain, under in vivo and in vitro culture conditions. Injection of individual nematodes into last instars of Galleria mellonella resulted in development of a similar number of females and hermaphrodites (35-40%) and 20-25% males. Increasing the number of nematodes injected into the insect did not change these proportions. In smaller insects (0.7-1.5 cm long), an increase in the proportion of hermaphrodites was recorded as compared with larger size cadavers (2.4-2.7 cm long). When individual hermaphrodites were placed on NGM, the proportion of hermaphrodites, females and male progeny was 63%, 31%, and 6%, respectively. Rearing on richer medium ("Dog-food" agar) resulted in reduction in the proportion of hermaphrodites. Nematodes introduced to the symbiotic bacterium obtained from other nematode strains (IS-5 and IS-33) developed similarly to the culture reared on the HP88 bacteria. Rearing the nematodes at a temperature range between 21 degrees C to 30 degrees C also did not have a significant effect on the sexual differentiation among nematodes cultured on NGM. The proportion of hermaphrodites increased as the starvation period of hatching nematode juveniles lengthened (>6 hr). The data obtained in the present study strongly suggest that the main factor affecting sex differentiation in H. bacteriophora is the nutrition source. The practical and biological implications of the results are discussed.

Sevoflurane in exhaled air of operating room personnel.

UNLABELLED: Evidence on potential health hazards arising from exposure to volatile anesthetics remains controversial. Exposure may, in principle, be supervised by monitoring of ambient air or, alternatively, in vivo. We used the Proton Transfer Reaction-Mass Spectrometry to screen the breath of 40 operating room staff members before operating room duty, 0, 1, 2, and 3 h after duty, and before commencing duty on the consecutive day, and control persons. Staff members exhibited significantly increased sevoflurane levels in exhaled air after duty, with a mean of 0.80 parts per billion as compared with baseline values of 0.26 parts per billion (P < 0.05). Analysis of variance with adjustment for within correlation (repeated measurements) showed a statistically significant time-effect (P < 0.001). We conclude that (a) Proton Transfer Reaction-Mass Spectrometry biomonitoring of exhaled sevoflurane can serve as a simple and rapid method to determine volatile anesthetic excretion after occupational exposure, and (b) significant concentrations of sevoflurane may be continuously present in persons exposed to sevoflurane on a daily basis. IMPLICATIONS: The present study depicts the profile of volatile anesthetics, isoflurane and sevoflurane, in exhaled air of ambulatory patients. Biomonitoring of expired anesthetic concentrations is a noninvasive and rapid method to determine volatile anesthetic excretion.

Role of actin filaments in endothelial cell-cell adhesion and membrane stability under fluid shear stress.

Clostridium botulinum C2 toxin (C2 toxin) and purified ADP-ribosylated-alpha-actin (ADP-r-alpha-actin) cause specific actin depolymerisation in living cells. This effect was used to investigate the actin microfilament system with particular emphasis on cell-cell adhesion and plasma membrane integrity in endothelial cells. C2 toxin caused time- and dose-dependent (15-100 ng/ml) changes in endothelial surface morphology (investigated by atomic force microscopy), intercellular gap formation and cell detachment under shear stress. Low concentrations of C2 toxin (1.5 ng/ml), however, did not induce cell detachment but inhibited shear stress-dependent cell alignment. Gap formation as well as cell loss under shear stress was also observed in cells microinjected with purified ADP-r-alpha-actin. Intercellular gap formation was mediated by increased alpha-catenin solubility (40%) due to actin filament depolymerisation. Disintegration of plasma membranes (measured by LDH release) and cell fragmentation during simultaneous exposure to shear stress and C2 toxin were due to a loss of more than 50% of membrane-associated actin. These data show that small disturbances in actin dynamics inhibit shear stress-dependent cell alignment; that depolymerisation of actin filaments increases the solubility of alpha-catenin, thus resulting in cell dissociation and that actin filaments of the membrane cytoskeleton are required to protect the cells from haemodynamic injury such as shear stress. Together, the study shows a heterogeneous regulation of actin filament dynamics at subcellular locations. Junction-associated actin filaments displayed the highest sensitivity whereas stress fibres were far more stable.