Des-γ-Carboxyprothrombin (DCP) and NX-DCP Expressions and Their Relationship with Clinicopathological Features in Hepatocellular Carcinoma

Aim

Des-γ-carboxyprothrombin (DCP) has been used as a tumor marker for hepatocellular carcinoma (HCC). Recently the DCP/NX-DCP ratio, calculated by dividing DCP by NX-DCP, has been reported useful in detecting HCC. The purpose of this study is to clarify the significance of DCP and NX-DCP expression in HCC tissues.

Methods

HCC and non-HCC tissue samples were obtained from 157 patients and were immunohistochemically examined for DCP and NX-DCP expression using anti-DCP antibody and anti-NX-DCP antibody. DCP and NX-DCP expression scores were calculated by multiplying staining intensity grade by percentage of stained area. Serum DCP and NX-DCP levels were determined in 89 patients. We evaluated the relationship between tumor expression, serum level, and pathomorphological findings.

Results

Intrahepatic metastasis (im) was significantly more frequent in cases with high DCP expression than in cases with low DCP expression. High NX-DCP expression was associated with significantly lower histological grade, and less frequent im or portal vein invasion (vp) than low NX-DCP expression. Serum DCP was correlated with DCP expression, but serum NX-DCP was not correlated with NX-DCP expression. DCP-positive (≥40 mAU/L), NX-DCP-positive (≥90 mAU/L), and DCP/NX-DCP ratio-positive (≥1.5) cases were associated with significantly larger tumor size and more frequent vp than negative cases. DCP was rarely expressed, but NX-DCP was frequently expressed in non-cancerous liver tissues. Patients with NX-DCP expression-negative tumors showed a lower survival rate than those with NX-DCP expression-positive tumors (p = 0.04), whereas the survival in serum NX-DCP-positive cases was lower than that of serum negative cases (p = 0.02).

Conclusions

DCP and NX-DCP were produced in HCC tissues, but differed in expression level and biological properties. DCP expression, serum DCP or NX-DCP level, and DCP/NX-DCP ratio were closely related to malignant properties of HCC.     

Microscopic study on resorption of β-tricalcium phosphate materials by osteoclasts

Sintered compounds prepared with β-tricalcium phosphate (β-TCP) are commonly used as biocompatible materials for bone regenerative medicine. Although implanted β-TCP is gradually replaced with new bone after resorption by osteoclasts, exactly how osteoclasts resorb β-TCP is not well understood. To elucidate this mechanism, we analyzed the structure of β-TCP discs on which mouse mature osteoclasts were cultured using scanning electron microscopy. We found that β-TCP was resorbed by mature osteoclasts on one side of each disc, as evidenced by the formation of multiple spine-like crystals at the exposed areas. Because osteoclasts secrete acid to resorb bone minerals, we mimicked this acidification by dipping β-TCP slices into HCl solution (pH 2.0). However, no spine-like crystals appeared even though the size of each β-TCP particle was reduced. On dentin slices, osteoclasts formed clear actin rings, which are cytoskeletal structures characteristic of bone-resorbing osteoclasts. No clear actin rings were observed in osteoclasts cultured on β-TCP slices, although small actin dots were observed. Analysis by transmission electron microscopy showed that osteoclasts attached to β-TCP particles. These results suggest that osteoclasts resorb β-TCP particles independently of clear actin ring formation.     

Stimulation of choline incorporation into a membrane fraction of rat liver by barbitals in vitro

A cytoplasmic post-mitochondrial extract (Sephadex-PM) from rat liver was active in incorporating [¹⁴C]methyl labeled choline into acid insoluble membrane material. The result of analysis of labeled phospholipid showed that most of the radioactivity was in lecithin. When Sephadex-PM was pre-incubated with hexobarbital, the choline incorporating activity was stimulated. Phenobarbital, but not 3-methylcholanthrene, also stimulated the incorporation. And the degree of the stimulation was dependent on the concentration of the drugs.     

Expression of cell adhesion molecule,Gicerin/CD146 during the formation of heart and in the cardiac hypertrophy

Molecular and Cellular Biochemistry - Gicerin/CD146 is a cell adhesion molecule which belongs to the immunoglobulin (Ig) superfamily. We have reported the existence of gicerin/CD146 in the nervous...     

Development of a novel immobilization method for enzymes from hyperthermophiles

Peptide tags containing tyrosines (Y-tag) were introduced at the C-terminus of a hyperthermophilic enzyme, alkaline phosphatase from Pyrococcus furiosus (PfuAP). Immobilization of the recombinant PfuAPs onto water-in-oil-in-water (W/O/W) type microcapsules was performed by an in situ polymerization method. All the recombinant PfuAPs prepared in this study were quantitatively immobilized onto microcapsules. The PfuAP-immobilized microcapsules showed no significant loss of enzymatic activity until the 5th round of assays. This result implies that the recombinant PfuAPs were covalently immobilized onto microcapsules. Immobilized PfuAP tagged with a Y-tag having the sequence GGYYY exhibited approximately a twofold higher catalytic activity compared with the wild-type PfuAP. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Minor Components of Rat Liver Ribosomal RNA as Possible Intermediates in the Degradation of 28S RNA in Vivo

The minor RNA components in large ribosomal subunits of rat liver were analyzed by gel electrophoresis. Quantitative analysis showed that these minor components, whose apparent molecular weights ranged from 8.48 × 10⁵ to 11.4 × 10⁵, represented 10 to 13% of the total high-molecular-weight ribosomal RNA.

It was elucidated that they were not artifacts arose during the cell homogenization, sub-cellular fractionation, RNA preparation and gel electrophoresis.

Labeling experiment in vivo showed that they were preferentially present in “old” ribosomes. It was predicted that these minor components were the intermediates in the degradation of 28S ribosomal RNA in vivo.

In the regenerating liver, where the degradation of proteins was reported to be blocked, the relative amount of the minor RNA components was decreased to about a half of that of normal liver. There was, however, no increase in their relative amount in the long-term starved rat liver, where RNA degradation should be going very rapidly.