Na,K-ATPase alpha3 subunit in the goldfish retina during optic nerve regeneration.

The goldfish optic nerve can regenerate after injury. To understand the molecular mechanism of optic nerve regrowth, we identified genes whose expression is specifically up-regulated during the early stage of optic nerve regeneration. A cDNA library constructed from goldfish retina 5 days after transection was screened by differential hybridization with cDNA probes derived from axotomized or normal retina. Of six cDNA clones isolated, one clone was identified as the Na,K-ATPase catalytic subunit alpha3 isoform by high- sequence homology. In northern hybridization, the expression level of the mRNA was significantly increased at 2 days and peaked at 5-10 days, and then gradually decreased and returned to control level by 45 days after optic nerve transection. Both in situ hybridization and immunohistochemical staining have revealed the location of this transient retinal change after optic nerve transection. The increased expression was observed only in the ganglion cell layer and optic nerve fiber layer at 5-20 days after optic nerve transection. In an explant culture system, neurite outgrowth from the retina 7 days after optic nerve transection was spontaneously promoted. A low concentration of ouabain (50-100 nm ) completely blocked the spontaneous neurite outgrowth from the lesioned retina. Together, these data indicate that up-regulation of the Na,K-ATPase alpha3 subunit is involved in the regrowth of ganglion cell axons after axotomy.

Occurrence of avenanthramides and hydroxycinnamoyl-CoA:hydroxyanthranilate N-hydroxycinnamoyltransferase activity in oat seeds.

Oat phytoalexins, avenanthramides, occur as constitutive components in seeds. The amounts of each avenanthramide were analyzed. The composition of avenanthramides in dry seeds was different from that in elicitor-treated leaves. In seeds, avenanthramide C was most abundant with an amount two times larger than that of avenanthramide A or B. On the other hand, avenanthramide A was the major component in elicitor-treated leaves. The total amount of avenanthramides in seeds increased 2.5 times during imbibition for 48 h although the composition did not change. The hydroxycinnamoyl-CoA:hydroxyanthranilate N-hydroxycinnamoyltransferase (HHT, EC 2.3.1.-) activity, which is responsible for the final condensation step in the avenanthramide biosynthesis, was detected in dry seeds. The activity was localized in endosperm and scutellum, and slightly increased during 48-h imbibition. The enzyme was partially purified by anion exchange chromatography from both dry seeds and elicitor-treated leaves The activity was separated into two peaks by chromatography, indicating that HHT consists of at least two isoforms. The substrate specificities of HHT isoforms from seeds were different from each other.

Percutaneous microwave coagulation therapy: an experimental study.

PURPOSE: Microwave coagulation therapy (MCT) is a surgical alternative for inoperable hepatocellular carcinomas (HCCs). We have recently developed a percutaneous method for using MCT under ultrasound guidance. The purpose of this study was to investigate the feasibility of percutaneous MCT (PMCT) in an animal model and correlate the ultrasound findings with histological results. MATERIALS AND METHODS: Microwaves were administered for 30, 45, 60 and 90 seconds to 12 cadaveric porcine livers in vivo one hour after sacrificing them, to determine the most suitable coagulation time for the percutaneous method. The cadaveric livers were then subjected to histologic evaluation. The temperature around the electrode was measured in both cadaveric and living livers during PMCT. Ultrasound-guided MCT was also performed in nine rabbits. The histological findings after PMCT were evaluated in the cadaveric and living livers, and the areas of coagulation necrosis were correlated with the ultrasound findings. RESULTS: After microwave emission, coagulation necrosis of a spindle shape occurred primarily from the base of the electrode. The maximum area of coagulation was obtained at 60 seconds. The maximum temperature of cadaveric liver under PMCT was 95 degrees at 3 mm from the electrode; that of living liver was 85.1 degrees at 5 mm. Ultrasound revealed hyperechoic areas after PMCT in both cadaveric and living livers. On microscopy, parenchymal necrosis of the liver was observed only in living livers one month after MCT. Hyperechoic areas measured with ultrasound were significantly larger than the actual necrotic areas (p < 0.01), probably due to air bubbles which developed within the tissue. CONCLUSIONS: PMCT completely coagulated the liver tissue around the electrode. These preliminary results indicate that PMCT should be an effective treatment for hepatic neoplasms. In terms of clinical application, the hyperechoic areas observed during PMCT appear to be considerably larger than the areas actually treated.

Parallel polarization electron paramagnetic resonance studies of the S1-state manganese cluster in the photosynthetic oxygen-evolving system.

Magnetic properties of the S1-state manganese cluster in the oxygen-evolving photosystem II were studied by parallel polarization electron paramagnetic resonance spectroscopy. Dark minus light spectra gave rise to a broad S1-state signal with a g value of about 4.9 [Dexheimer, S. L., Klein, M. P. (1992) J. Am. Chem. Soc. 114, 2821-2826]. Temperature variation of the signal intensity between 1.9 and 10 K observed in PS II with a sucrose buffer indicates that the signal originates from an excited state with a spin S of 1 with separation from the ground state (S = 0) of about 2.5 K. The S1-state signal was also observed in the sucrose buffer supplemented by 50% glycerol. However, no S1-state signal was detected by addition of 3% methanol or 30% ethylene glycol in the sucrose buffer, although illumination at 200 K in the presence of these alcohols induced the normal multiline S2 signal. Furthermore, modification of the Mn cluster by Cl- or Ca2+ depletion from PS II membranes failed to produce a detectable S1-state signal. A possible magnetic structure of the Mn cluster responsible for the generation of the S1-state signal is discussed on the basis of these observations.

Detection of hepatocellular carcinoma by intraarterially enhanced ultrasonography with CO2 microbubbles. Comparison with DSA, dynamic CT, and Lipiodol CT.

PURPOSE: To evaluate the diagnostic value of contrast-enhanced US with CO2 microbubbles (EU) for HCCs. Detectability was compared with DSA, dynamic CT, and Lipiodol CT. MATERIAL AND METHODS: Forty-seven histologically proven HCCs detected with US were evaluated with EU, DSA, and dynamic CT. In 23 patients (35 lesions), Lipiodol CT was also performed. The size of the tumors ranged from 8 to 71 mm (average 28.1 mm); 24 lesions were smaller than 20 mm and 23 lesions were larger than 20 mm. RESULTS: Overall detection was possible in 40 of 47 lesions (85%) by EU, in 32 of 47 (68%) by DSA, in 33 of 47 (74%) by dynamic CT, and in 27 of 35 (77%) by Lipiodol CT. In tumors smaller than 20 mm, detection was possible in 21 of 24 lesions (88%) by EU, 14 of 24 (58%) by DSA, 14 of 24 (58%) by dynamic CT, and 11 of 17 (65%) by Lipiodol CT. CONCLUSION: EU has significant diagnostic value for detection of HCCs, particularly tumors smaller than 20 mm.

Optimal duration and temperature of prewarming.

BACKGROUND: Core hypothermia developing immediately after induction of anesthesia results largely from an internal core-to-peripheral redistribution of body heat. Although difficult to treat, redistribution can be prevented by prewarming. The benefits of prewarming may be limited by sweating, thermal discomfort, and efficacy of the warming device. Accordingly, the optimal heater temperature and minimum warming duration likely to substantially reduce redistribution hypothermia were evaluated. METHODS: Sweating, thermal comfort, and extremity heat content were evaluated in seven volunteers. They participated on two study days, each consisting of a 2-h control period followed by 2 h of forced-air warming with the heater set on "medium" (approximately 40 degrees C) or "high" (approximately 43 degrees C). Arm and leg tissue heat contents were determined from 19 intramuscular needle thermocouples, ten skin temperatures, and "deep" foot temperature. RESULTS: Half the volunteers started sweating during the second hour of warming. None of the volunteers felt uncomfortably warm during the first hour of heating, but many subsequently did. With the heater set on "high," arm and leg heat content increased 69 kcal during the first 30 min of warming and 136 kcal during the first hour of warming, representing 38% and 75%, respectively, of the values observed after 2 h of warming. The increase was only slightly less when the heater was set to "medium." CONCLUSIONS: Neither sweating nor thermal discomfort limited heat transfer during the first hour of warming. Thirty minutes of forced-air warming increased peripheral tissue heat content by more than the amount normally redistributed during the first hour of anesthesia. The large increase in arm and leg heat content during prewarming thus explains the observed efficacy of prewarming.