The repetitive activation of extracellular signal-regulated kinase is required for renal regeneration in rat

In this study, we investigated the activation of p42 extracellular signal-regulated kinase (ERK2) during renal regeneration after HgCl2-induced acute renal failure (ARF) in rat. ERK2 activation was observed at 5 and 29 hr after HgCl2 injection, respectively. The tyrosine phosphorylation of hepatocyte growth factor receptor (c-MET) occurred between 2.5 and 5 hr after the treatment. On the other hand, the phosphorylation of epidermal growth factor receptor (EGFR) was transiently observed at 29 hr after the injection. The peak of ornithine decarboxylase activity as a marker of G1 phase was at 10 hr, and subsequently the labeling index of proliferating cell nuclear antigen as a marker of S phase increased at 53 hr. These results indicate that the repetitive activation of ERK2 related to the phosphorylation of c-MET and EGFR is required for the renal regeneration in HgCl2-induced ARF of rat.     

Prevention of bone loss by percutaneous estradiol implants in ovariectomized rats

This study was conducted to investigate whether hydroxyapatite (HAP) is appropriate as a percutaneous drug carrier for estradiol (E2) for the suppression of bone loss. Ten-week-old female Sprague-Dawley rats were subjected either to bilateral ovariectomy (OVX) or to sham surgery (control). Ovariectomized rats were implanted percutaneously with E2-HAP disks containing low, medium or high doses of estradiol (50, 250, or 500 micrograms E2/rat, respectively). Ovariectomized rats without implant and OVX rats implanted only with HAP served as additional controls. All rats were sacrificed 90 days after surgery. At the end of the experiment, bone mineral density of the lumbar spine was measured by dual energy X-ray absorption, and serum E2 was assayed by radioimmunoassay. The bone mineral density of OVX and HAP-treated OVX rats decreased by 18% compared to sham surgery rats, but decreased by only 13, 7, and 3% in rats treated with 50, 250, and 500 micrograms E2/rat, respectively. The in vitro release of E2 from E2-HAP devices was determined by an HPLC method. Estradiol release from the HAP devices followed almost a zero-order kinetics. Estradiol remained intact in E2-HAP implants for up to six months when stored at 5, 25, and 40 degrees C. This study indicates that E2-HAP implants are effective in suppressing bone loss in the spine of OVX rats in a dose-dependent manner.     

Void fraction measurement by a gamma-ray densitometer under instantaneous pipe rupture

A high-response gamma-ray densitometer was developed for the measurement of void fraction caused by the flashing vaporization of high-pressure and -temperature water under an instantaneous pipe break accident of a boiling water reactor, BWR. The initial conditions of the water were 6.86 MPa in pressure and saturation temperature. In order to prove the reliability and accuracy, the calibration test by dropping the acrylic void simulators and the air injection test into the cold water filled in the pipe were conducted.The following results are obtained in the experiments: (1) the cone slit method is very useful to increase the measuring accuracy, (2) it is clearly observed that the apparent increase of the void fraction occurs after the rarefaction wave passes, (3) the first maximum of the void fraction occurs with some delay time after break. Secondly, the minimum void fraction concurs with the maximum pressure in the pressure recovering process.     

The effect of propionate on lipid synthesis in rat lymphocytes

1. The effect of propionate on lipid synthesis in lymphocytes cultured for 24 hr and incubated for 2 hr was investigated. 2. [1-14C]-propionate was incorporated mainly into phospholipids in both control and concanavalin A (Con A) stimulated cultured lymphocytes. 3. The content of free coenzyme A markedly decreased in 2 hr incubated lymphocytes when propionate was added to the medium at concentrations from 10 to 100 mmol/l. 4. Propionate at 40 mmol/l decreased the incorporation of [1-14C]-palmitate into phospholipids (86%), triacylglycerol (87%) and cholesterol ester (98%) and increased in cholesterol (133%) of cultured lymphocytes. 5. Addition of propionate into the culture medium at 2.5 and 5.0 mmol/l concentrations markedly increased the activity of hydrolases of various acylCoA derivatives. 6. The results suggest that propionate may reduce the content of acylCoA and so its esterification and this might be important for the regulation of lymphocytes proliferation.     

ALL-1 interacts with unr, a protein containing multiple cold shock domains

The ALL-1 gene is involved in human acute leukemia through chromosome translocations and fusion to partner genes, or through partial tandem duplications. ALL-1 is the human homologue of Drosophila trithorax which transregulates the homeotic genes of the Antennapedia and bithorax complexes controlling body segment identity. ALL-1 encodes a very large protein of 3968 amino acids which presumably interacts with many proteins. Here we applied yeast two hybrid screening to identify proteins interacting with the N-terminal segment of ALL-1. One protein obtained in this way was the product of the unr gene. This protein consists of multiple repeats homologous to the cold shock domain (CSD), a motif common to some bacterial and eukaryotic nucleic acids-binding proteins. The minimal region on unr required for the interaction with ALL-1 included two CSD and two intervening polypeptides. The interaction was confirmed by in vitro binding studies, and by coimmunoprecipitation from COS cells overexpressing the relevant segments of the two proteins. These results suggest that unr is involved in an interaction of ALL-1 with DNA or RNA.     

Calcium promotes cell survival through CaM-K kinase activation of the protein-kinase-B pathway

The protection against apoptosis provided by growth factors in several cell lines is due to stimulation of the phosphatidylinositol-3-OH kinase (PI(3)K) pathway, which results in activation of protein kinase B (PKB; also known as c-Akt and Rac) and phosphorylation and sequestration to protein 14-3-3 of the proapoptotic Bcl-2-family member BAD. A modest increase in intracellular Ca2+ concentration also promotes survival of some cultured neurons through a pathway that requires calmodulin but is independent of PI(3)K and the MAP kinases. Here we report that Ca2+/calmodulin-dependent protein kinase kinase (CaM-KK) activates PKB directly, resulting in phosphorylation of BAD on serine residue 136 and the interaction of BAD with protein 14-3-3. Serum withdrawal induced a three- to fourfold increase in cell death of NG108 neuroblastoma cells, and this apoptosis was largely blocked by increasing the intracellular Ca2+ concentration with NMDA (N-methyl-D-aspartate) or KCl or by transfection with constitutively active CaM-KK. The effect of NMDA on cell survival was blocked by transfection with dominant-negative forms of CaM-KK or PKB. These results identify a Ca2+-triggered signalling cascade in which CaM-KK activates PKB, which in turn phosphorylates BAD and protects cells from apoptosis.     

Effect of selective and non-selective muscarinic blockade on baclofen inhibition of gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats

The effects of baclofen, a gamma-amino-n-butyric acid receptor B agonist, on gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine and how its effects are influenced by selective (M1) and non-selective (M1 and M2) pharmacological blockade of muscarinic receptors were investigated in inbred Wistar rats. Rats were given s.c. injections of 8 mg/kg body wt baclofen with and without 0.5 mg/kg body wt atropine (non-selective M1 and M2 muscarinic receptor antagonist) or 1.0 mg/kg body wt pirenzepine (selective M1 muscarinic receptor antagonist) every other day after a 25 week carcinogen treatment. At week 52 baclofen significantly decreased the incidence of gastric cancers. Concomitant treatment with atropine significantly attenuated the inhibition by baclofen of gastric carcinogenesis, but combined use with pirenzepine had no significant effect on the inhibition by baclofen of gastric carcinogenesis. Baclofen also significantly decreased the labeling index of the antral mucosa. Baclofen plus atropine attenuated the decrease in the labeling index of the antral mucosa due to baclofen, but baclofen plus pirenzepine had no significant effect on the labeling index. These results suggest that the inhibition of gastric carcinogenesis by baclofen is mediated through muscarinic receptors and M2 receptors, but not M1 receptors, are involved in this response.     

Regulation of albumin mRNA and its promoter-binding nuclear factors under different perioperative nutritional methods in hepatectomized rats

BACKGROUND: Regulation of perioperative albumin synthesis under parenteral (PN) and enteral (EN) nutrition was investigated. METHODS: Rats were divided into PN and EN groups. Both groups received the same regimen of artificial nutrition for 7 days and then underwent 70% hepatectomy. Serum albumin and mRNA levels of albumin and its promoter-binding nuclear factors (C/EBPalpha, beta, and DBP) were measured. RESULTS: Serum albumin and albumin mRNA in the PN group were significantly lower than those in the EN group at 72 hours after hepatectomy. Preoperative and postoperative DBP and C/EBPalpha mRNA levels in the EN group were significantly higher than those in the PN group. CONCLUSION: Serum albumin was well maintained by EN after hepatectomy owing to an early recovery of albumin mRNA level and its nuclear factor mRNA levels (C/EBPalpha and DBP). Compared with PN, EN is a more advantageous from of perioperative nutrition as pertains to albumin synthesis.     

A Fully-Automated Electron Beam Test System for VLSI Circuits

A fully automated, stroboscopic electrobeam test system that analyzes the behavior of logic VLSI circuits, this system consists of a stroboscopic electron-beam tester combined with an LSI CAD system. LSI circuit design data, read from the CAD system, provides a designed map. The host computer performs interconnection pattern recognition by superimposing this map onto an observed stroboscopic SEM image. Then, once the circuit nodes for voltage waveform measurements are automatically determined on the superimposed map. Next, the electron beam is positioned on the actual circuit-under-test wires. These automatic processes result in measured waveforms, which are displayed on the host computer terminal. This system has been applied to a 2.3K-gate logic LSI circuits, and has been successful in locating the critical path. This system, coupled with the recently developed fault diagnostic electron-beam tester, Finder, constitutes a unified electron-beam test system.     

Apparatus for torsional braid analysis by a digital data analyzer

As apparatus for torsional braid analysis (TBA), which is a variant of the torsional pendulum technique, a new method for recording the damped wave electrically, using an electric mater as a transducer, is described. In order to process a large volume of data, an instrument to print out digitally the amplitude and period of oscillation has been developed. The thermomechanical behavior of poly(vinyl chloride) is presented so as to demonstrate the use of the present TBA apparatus.