Utility of three dimension fast asymmetric spin-echo (3D-FASE) sequences in MR sialographic sequences: model and volunteer studies.

OBJECTIVES: To evaluate the utility of 3D-FASE for the visualization of salivary gland ducts for use in MR sialographic sequences. METHODS: We compared MR sialographic images and virtual endoscopic views from 3D-FASE with those from three kinds of sequences described by previous reports in a 3D parotid gland duct model and volunteer. The four sequences were two-dimension fast spin-echo (2D-FSE), three-dimension fast spin-echo (3D-FSE), two-dimension fast asymmetric spin-echo (2D-FASE), and three-dimension fast asymmetric spin-echo (3D-FASE). RESULTS: In the 3D parotid gland duct model, image visibility on visual score was clearest with 3D-FSE, followed by 3D-FASE (P = 0.028). In the volunteers, the visualization of images improved in the following order: 3D-FASE > 3D-FSE > 2D-FSE > 2D-FASE. CONCLUSIONS: The technique of 3D-FASE sequencing is more suitable and useful for MR sialography with an appropriate acquisition time.

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.

Properties of Ca(2+)-mediated inactivation of L-type Ca channel in smooth muscle cells of the guinea-pig urinary bladder.

The properties of Ca(2+)-mediated inactivation as revealed by a conventional double-pulse protocol were examined by using the whole-cell patch clamp technique. A U-shaped relationship between the conditioning potential and the Ca2+ current (ICa) inactivation was observed, with a maximum inactivation of 52 +/- 4% (n = 5) at 10 mV with 0.5 mM EGTA in the patch pipettes. The maximum inactivation was reduced significantly, to 31 +/- 5.7% (n = 12) and 32 +/- 7.0% (n = 5), when a high concentration of EGTA (20 mM) or a more efficient Ca2+ chelator, BAPTA, was included in the patch pipettes, respectively. The same double-pulse protocol was applied under conditions where the stored Ca2+ was depleted by using caffeine or the stored Ca2+ release function was blocked by using ryanodine or procaine and heparin. No significant difference in the maximum ICa inactivation before (45%) and after (50%) application of 10 mM caffeine was observed. The maximum ICa inactivations of 48 +/- 3.2% (n = 4) and 52 +/- 8.4% (n = 6) were still observed after treatment of the cell with ryanodine (20 microM) or loading 10 mM procaine and 1 mg/mL heparin in the patch pipettes, respectively. These results suggest that Ca2+ mobilization from an internal Ca2+ store is not essential for the Ca(2+)-mediated inactivation observed in the double-pulse experiment, rather influx of Ca2+ through a voltage-dependent Ca channel seems to be important for ICa inactivation.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Structure and distribution of lymphatic capillaries and fenestrated blood capillaries in the conduction system of the rabbit heart.

The distribution and structure of lymphatic and blood capillaries in the rabbit heart conduction system were investigated by transmission electron microscopy. The sinuatrial node, atrioventricular node, and atrioventricular bundle possessed a rich network of lymphatic capillaries, which were situated not only at the periphery but also in the interior of the conduction system. The fine structure of these lymphatic capillaries was essentially similar to those within the atria and the ventricles. Although blood capillaries within working myocardium were nonfenestrated, the heart conduction system was often supplied by fenestrated blood capillaries. In the atrioventricular node and bundle especially, fenestrated blood capillaries and lymphatic capillaries were topographically associated, forming an extensive microcirculatory system. The presence of fenestrated capillaries suggests that a fast transcapillary passage of metabolites occurs in these regions, while the lymphatic capillaries may play an important role in the removal of macromolecules and excess intercellular fluid.