Prevention of acute liver failure in rats with reversibly immortalized human hepatocytes

Because of a critical shortage in suitable organs, many patients with terminal liver disease die each year before liver transplantation can be performed. Transplantation of isolated hepatocytes has been proposed for the temporary metabolic support of patients awaiting liver transplantation or spontaneous reversion of their liver disease. A major limitation of this form of therapy is the present inability to isolate an adequate number of transplantable hepatocytes. A highly differentiated cell line, NKNT-3, was generated by retroviral transfer in normal primary adult human hepatocytes of an immortalizing gene that can be subsequently and completely excised by Cre/Lox site-specific recombination. When transplanted into the spleen of rats under transient immunosuppression, reversibly immortalized NKNT-3 cells provided life-saving metabolic support during acute liver failure induced by 90% hepatectomy.     

Replication-dependent loss of 5-hydroxymethylcytosine in mouse preimplantation embryos

Although global erasure of DNA methylation has been observed in zygotes and primordial germ cells, the responsible enzyme(s) have been elusive. The demonstration that members of the Tet (ten eleven translocation) family of proteins are capable of catalyzing conversion of 5-methylcytosine (5mC) of DNA to 5-hydroxymethylcytosine (5hmC) raises the possibility that Tet proteins may participate in this process. Indeed, recent studies have implicated the involvement of Tet3 in the conversion of 5mC to 5hmC in zygotes. This result, combined with the demonstration that Tet proteins can further oxidize 5hmC to 5-carboxylcytosine followed by excision by thymine-DNA glycosylase, raises the possibility that active demethylation may take place in a process that involves Tet3-mediated oxidation followed by base excision repair. We demonstrated by immunostaining of mitotic chromosome spreads of preimplantation embryos that the 5hmC associated with the paternal genome in zygotes is gradually lost during preimplantation development. Our study suggests that, although the conversion of 5mC to 5hmC in zygotes is an enzyme-catalyzed process, loss of 5hmC during preimplantation appears to be a DNA replication-dependent passive process.     

Magmatic dike resonances inferred from very-long-period seismic signals

Very-long-period (VLP) signals showing simple decaying harmonic oscillations with periods near 10 seconds and lasting for about 300 seconds were observed in association with an earthquake swarm that occurred beneath Hachijo Island, Japan. Results from the source-mechanism analysis and waveform simulation based on a fluid-filled crack model consistently point to the resonance of a dike filled with a basaltic magma as the source of the VLP signals. Thus, VLP signals can be used to probe the state of the fluid and dynamic processes within a volcanic system.     

DNA methylation analysis on satellite I region in blastocysts obtained from somatic cell cloned cattle

Many observations have been made on cloned embryos and on adult clones by somatic cell nuclear transfer (SCNT), but it is still unclear whether the progeny of cloned animals is presenting normal epigenetic status. Here, in order to accumulate the information for evaluating the normality of cloned cattle, we analyzed the DNA methylation status on satellite I region in blastocysts obtained from cloned cattle. Embryos were produced by artificial insemination (AI) to non‐cloned or cloned dams using semen from non‐cloned or cloned sires. After 7 days of AI, embryos at blastocyst stage were collected by uterine flushing. The DNA methylation levels in embryos obtained by using semen and/or oocytes from cloned cattle were similar to those in in vivo embryos from non‐cloned cattle. In contrast, the DNA methylation levels in SCNT embryos were significantly higher (P < 0.01) than those in in vivo embryos from non‐cloned and cloned cattle, approximately similar to those in somatic cells used as donor cells. Thus, this study provides useful information that epigenetic status may be normal in the progeny of cloned cattle, suggesting the normality of germline cells in cloned cattle.     

The study on method to draw large-scale soil map in diluvial soil area in Hokkaido, using digital elevation data for a 10 m grid

(pp. 59–66)
In order to understand the detailed soil distribution of a terrace with a diluvial deposit, the method to draw a large-scale soil map was studied in Urausu Town of Sorachi district by combinig soil survey and digital elevation data for a 10 m grid.
The results are summarized as follows:

• 1) 

  From a soil survey, soils in the research area were classified into 3 soil series groups according to Classification of Cultivated Soils in Japan, Third Approximation, which were Skeletal Terrace Brown Forest Soils, Fine-textured Aquic Brown Forest Soils and Fine-textured Haplic Gray Upland Soils. In addition, Fine-textured Haplic Gray Upland Soils · were classified into 2 categories based on the abundance of gravel in the subsoil.

       

Liquid chromatographic determination of melamine in beverages

A liquid chromatographic method is described for the determination of melamine in beverages. Melamine is separated by column chromatography using cation and anion exchange resin and determined by ion-pair liquid chromatography using an ODS column and a mixture of acetonitrile and 0.05M phosphate buffer (pH 3.0) containing 0.005M sodium 1-laurylsulfate (1 + 4, v/v) as mobile phase. Recoveries of melamine ranged between 90.3 +/- 7.8 and 102.1 +/- 5.6% at levels of 0.6 to 2.4 ppm in 4 kinds of beverages. The quantitation limit was 2.5 micrograms melamine in 50 mL beverage. The method was applied to the migration test of melamine from melamine-formaldehyde resin products to the beverages.