Instability of background fat intensity suppression using fat-saturated (FS) MR imaging techniques according to region and reconstruction procedure in patients with oral cancer.

The purpose of the present study is to evaluate the background fat intensity suppression instability of each area in the head and neck region, and in the post-reconstruction with metal plate and myocutaneous flap, of patients with oral cancer using fat-saturated (FS) images. STIR and FS T2-weighted images at pre- and post-surgery in 59 patients with oral cancer were scored for uniformity of fat suppression and tissue conspicuity in each region of the head and neck. The scores of FS on uniformity of fat suppression pre-operatively were worse than those of STIR in the mandibular level, but not lesion and tissue conspicuity. However, the deterioration both of scores between pre- and post-surgery using FS was worse than that using STIR using metal plate and/or myocutaneous flap. At diagnosis, we should recognize on MR images using FS that instability of the status of fat suppression might be brought about by respective area and reconstruction with metal plate and myocutaneous flap of patients with oral cancer.

Monitoring of white-rot fungus during bioremediation of polychlorinated dioxin-contaminated fly ash.

Bioremediation is a low-cost treatment alternative for the cleanup of polychlorinated-dioxin-contaminated soils and fly ash when pollution spread is wide-ranging. An interesting fungus, Ceriporia sp. MZ-340, with a high ability to degrade dioxin, was isolated from white rotten wood of a broadleaf tree from Kyushu Island in Japan. We have attempted to use the fungus for bioremediation of polychlorinated-dioxin-contaminated soil on site. However, we have to consider that this trial has the potential problem of introducing a biohazard to a natural ecosystem if this organism is naturalized. We have therefore developed a monitoring system for the introduced fungus as a part of the examination and evaluation of bioremediation in our laboratory. We have also developed a PCR-based assay to reliably detect the fungus at the bioremediation site. DNA isolated from the site was amplified by PCR using a specific primer derived from internal transcribed spacer region (ITS: ITS1, 5.8S rDNA and ITS2) sequences of Ceriporia sp. MZ-340. We successfully monitored Ceriporia sp. MZ-340 down to 100 fg/ micro l DNA and down to 2 mg/g mycelium. We also successfully monitored the fungus specifically at the bioremediation site. The polychlorinated dibenzo- p-dioxin and polychlorinated dibenzofuran content was observed to decrease in response to treatment with the fungus. The species-specific PCR technique developed in the present work is useful in evaluating the possibility of on-site bioremediation using the fungus Ceriporia sp. MZ-340.

Voltage-dependent suppression of calcium current by caffeine in single smooth muscle cells of the guinea-pig urinary bladder.

The suppressive action of caffeine on L-type Ca current (Ica) in smooth muscle cells of the guinea-pig urinary bladder was investigated using the whole-cell patch clamp technique. Caffeine (5-30 mM) suppressed Ica, the effect having two phases: a rapid and transient suppression of Ica, which was followed by a sustained suppression. When intracellular Ca2+ was strongly buffered by the Ca2+ chelator EGTA (20 mM) or BAPTA (5 mM) in the patch pipette, the transient suppression of Ica was abolished, whereas the sustained effect remained. Similarly, inclusion of both 10 mM procaine and 1 mg/ml heparin in the patch pipette blocked the transient suppression of Ica, but did not block the sustained effect. The degree of the sustained effect of caffeine on Ica was dose-dependent with a kd of 20 mM. Application of the cyclic AMP analogue, 8-bromo-cyclic AMP (100 microM) or forskolin (10 microM) to the bath failed to mimick the sustained suppression of Ica, suggesting that inhibition of phosphodiesterase activity was not involved in the caffeine action. The steady-state activation curve remained unchanged by 10 mM caffeine but the steady-state inactivation curve was significantly shifted in the negative direction by 15.6 mV in 1.8 mM Ca2+ solution or by 10 mV in 1.8 mM Ba2+ solution. From these results it appears that caffeine inhibits L-type Ica via two mechanisms: (1) it releases Ca2+ from an internal store causing a transient Ca2+ -mediated inactivation of the Ca channel; (2) it inhibits Ca channel via a mechanism that does not require such a Ca2+ release. It is possible that caffeine suppresses Ica through a preferential binding to the inactivated state of L-type Ca channel.

Alterations in gap junctions of human endometrial epithelial cells during normal menstrual cycle--freeze-fracture electron microscopic study.

Gap junctions between human endometrial epithelial cells were studied at various phases of the normal menstrual cycle by freeze-fracture electron microscopy. The junctions changed in number and size according to the phases of the menstrual cycle. Only small and few gap junctions were found in the early proliferative phase. In the early secretory phase the junctions were larger and found more often in the earlier phase. In the late secretory phase the junctions were much smaller than in the early secretory phase. The cyclical changes of the junctions may have a role in controlling the proliferation and differentiation of the endometrial epithelium.