Transmyocardial revascularization aggravates myocardial ischemia around the channels in the immediate phase

We examined whether transmyocardial revascularization (TMR) relieves myocardial ischemia by increasing regional perfusion via the transmural channels in acute canine experiments. Regional blood flow during transient coronary ligation (2 min) was compared before and 30 min after TMR, and at the third transient ischemia the mid-left ventricle (LV) was cut and immediately frozen along the short axis for the analysis of NADH fluorescence in the regions around the TMR channels. In low-resolution analysis (2-4 g tissue or 2-3 cm(2) area), regional perfusion was not significantly altered after TMR, and NADH fluorescence was observed throughout the ischemic region without significant spatial variation. High-resolution analysis (2.8 mg, 1 mm x 1 mm) revealed that the flow after TMR was lower, and NADH fluorescence was higher in the regions close to the channels (1-2 mm) than in the regions 3-4 mm away from them. Creating TMR channels did not improve the regional perfusion and rather aggravated the local ischemia in the vicinity of the channels in the immediate phase.     

Streptococcal preparation OK-432: a new maturation factor of monocyte-derived dendritic cells for clinical use

For vaccinations based on dendritic cells (DCs), maturation of DCs is critical to the induction of T-cell responses. We tested the efficacy of streptococcal preparation OK-432 as a Good Manufacturing Practice (GMP)-grade maturation agent. OK-432 is currently used in Japan as a cancer immunotherapy drug. Immature monocyte-derived dendritic cells (imMo-DCs) isolated from human peripheral blood monocytes stimulated with granulocyte-macrophage colony stimulating factor and interleukin-4 were exposed to maturation factors, i.e., lipopolysaccharide (LPS), tumor necrosis factor alpha (TNF-alpha) plus prostaglandin E2 (PGE2), and OK-432 for 2 days. OK-432 increased expression of activation- and maturation-related molecules such as HLA-DR, CD80, CD83, and CD86 in imMo-DCs at levels similar to that of TNF-alpha plus PGE2, and higher than that of LPS. All agents examined induced allogeneic T-cell proliferation at a similar level. Only OK-432 caused significant production of interleukin-12 (IL-12) p70 and interferon gamma (IFN-gamma) at both the mRNA and protein levels in imMo-DCs. Neutralizing antibody against IL-12 p70 blocked IFN-gamma secretion from OK-432-stimulated Mo-DCs. IL-12 p70 produced by OK-432-stimulated imMo-DCs induced secretion of IFN-gamma by CD4+ T cells. OK-432 and LPS activated nuclear factor kappa B (NF-kappaB) in imMo-DCs. Both secretion of IL-12 p70 and IFN-gamma and activation of NF-kappaB induced by OK-432 were suppressed when imMo-DCs were pretreated with cytochalasin B. These results indicate that uptake of OK-432 by imMo-DCs is an early critical event for IL-12 p70 production and that NF-kappaB activation induced by OK-432 also contributes partially to IL-12 p70 production. In conclusion, OK-432 is a GMP-grade maturation agent and may be a potential tool for DC-based vaccine therapies.     

Structural and systematic study of an unusual tracheid type in cacti

Wide-band tracheids are a specialized tracheid type in which an annular or helical secondary wall projects deeply into the cell lumen. They are short, wide and spindle-shaped, and their bandlike secondary walls cover little of the primary wall, leaving most of it available for water diffusion. Wide-band tracheids appear to store and conduct water while preventing the spread of embolisms. They may be the most abundant tracheary element in the xylem, but they are always accompanied by at least a few vessels. Typically, fibers are absent wherever wide-band tracheids are present. Wide-band tracheids occur in the primary and secondary xylem of succulent stems, leaves and roots in genera of all three subfamilies of Cactaceae but were not found in the relictual genusPereskia, which lacks succulent tissues. In the large subfamily Cactoideae, wide-band tracheids occur only in derived members, and wide-band tracheids of North American Cactoideae are narrower and are aligned in a more orderly radial pattern than those of South American Cactoideae. Wide-band tracheids probably arose at least three times in Cactaceae.     

Induction and isolation of pigmentation mutants of Porphyra yezoensis (Bangiales, Rhodophyta) by heavy-ion beam irradiation

The present study describes the isolation of pigmentation mutants of Porphyra yezoensis Ueda induced by heavy-ion beam irradiation for the first time. The gametophytic blades were irradiated with ¹²C⁺⁶ ion beams within a dose range of 25–400 Gy. From the survival rate and cell growth of the irradiated blades, it is suggested that a dose of 150 Gy or less is suitable to induce mutation for the isolation of mutants of P. yezoensis . After irradiation, red, green and deep reddish brown-colored gametophytic blades developed from archeospores that were released from each of the mutated cell clusters of the respective different colors, and the red mutant strain (IBY-R1) and green mutant strain (IBY-G1) were established as a conchocelis colony in culture. Blades of the mutants were characterized by their growth and photosynthetic pigment contents compared with those of the wild-type. From these results, it is clear that heavy-ion beam mutagenesis will be an effective tool for genetic and breeding studies of Porphyra , and also for other algal research.     

EPR studies on a Hipip type iron-sulfur center in the succinate dehydrogenase segment of the respiratory chain

In addition to the two species of ferredoxin-type iron-sulfur centers (Centers S-1 and S-2), a Hipip-type iron-sulfur center (Center S-3) has been detected in the reconstitutively active soluble succinate dehydrogenases. E_m7,4 determined in a particulate, antimycin A sensitive succinate-cytochrome $\text{c}$ reductase is +60 ± 15 mV. This center is extremely labile towards oxygen in a manner similar to the reconstitutive activity of the dehydrogenase. Even freshly prepared reconstitutively active enzyme shows a considerably diminished content of Center S-3 relative to flavin and displays a partly modified spectra. All reconstitutively inactive dehydrogenases give rise to a highly modified or no Center S-3 spectra at all. These observations indicate that Center S-3 is a constituent of succinate dehydrogenase and plays a role in the physiological function of the enzyme, $\text{i.e.}$ transferring electrons most probably to ubiquinone.     

Inhibition of Rac1 promotes BMP-2-induced osteoblastic differentiation

Small G proteins of the Rho family are pivotal regulators of several signaling networks. The Ras homolog family (Rho) and one of its targets, Rho-associated protein kinase (ROCK), participate in a wide variety of biological processes, including bone formation. A previous study has demonstrated that the ROCK inhibitor Y-27632 enhanced bone formation induced by recombinant human bone morphogenetic protein-2 (BMP-2) in vivo and in vitro. However, the effect of other Rho family members, such as Ras-related C3 botulinum toxin substrate 1 (Rac1) and cell division cycle 42 (Cdc42), on bone formation remains unknown. In this study, we investigated whether Rac1 also participates in BMP-2-induced osteogenesis. Expression of a dominant-negative mutant of Rac1 enhanced BMP-2-induced osteoblastic differentiation in C2C12 cells, whereas a constitutively active mutant of Rac1 attenuated that effect. Knockdown of T-lymphoma invasion and metastasis 1 (Tiam1), a Rac-specific guanine nucleotide exchange factor, enhanced BMP-2-induced alkaline phosphatase activity. Further, we demonstrated that BMP-2 stimulated Rac1 activity. These results indicate that the activation of Rac1 attenuates osteoblastic differentiation in C2C12 cells.     

Establishment and characterization of new cell lines from human renal cell carcinoma

We have characterized seven human renal cell carcinoma cell lines established from primary sites of five patients between 1987 and 1989. Two lines, OUR-20P and OUR-20S, were derived from the OUR-20 cells by cloning with a dilution method 3 months after the primary culture. These three cell lines were tumorigenic in athymic nude mice when inoculated subcutaneously. Examined by a dye uptake method, OUR-20 was highly sensitive to interferon-alpha (IFN-alpha); OUR-20P, OUR-20S and OUR-30 showed slight sensitivities, while the other three cell lines were insensitive. All seven cell lines have been maintained for more than 2 years and over 50 passages in vitro. Cytogenetic analyses performed 1.5 to 3 years after the starts of primary cultures indicated that all seven cell lines, which exhibited different morphologies in phase-contrast micrographs, were aneuploid with modal chromosome numbers 41 to 89.     

Alteration of opioid receptors in seizure-susceptible El mouse brain

The distribution density of opioid receptors in the brain of El mice (seizure-susceptible strain) was examined to determine the relation between seizures and the opioid system. Saturation curves and Scatchard plots of [³H]2-d-alamine-5-d-leucine enkephalin binding revealed that the opioid delta receptor density in adult El mice during interictal periods was significantly increased in the cerebral cortex, hippocampus, and septal area. It was further shown that the concentration of such receptors in 25-day-old El mice that had no seizures was also significantly increased in the hippocampus and septal area, with no changes in apparent affinities, as compared with in the corresponding regions in ddY mice (seizure-nonsusceptible strain; the mother strain of El). Such up-regulation of opioid receptors in the El mouse brain could result from deficits in endogenous opioid peptides, which could be associated with the pathogenesis of seizure diathesis in the El mouse.