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Biomedical subjects

K Katagiri

Publications and source records attributed to K Katagiri.

At least 91 records · Page 5Linked to original sources
PubMed1990

Comparative sequential changes in serum and biliary levels of bile acid components after a single dose of D-galactosamine or partial hepatectomy in the rat.

In order to characterize changes in bile acid profile during liver cell damage and regeneration, levels of bile acids in serum and bile were determined by high performance liquid chromatography (HPLC) in F344 rats treated with a single dose of D-galactosamine (galactosamine, 300 mg/kg, i.p.) or subjected to two-thirds partial hepatectomy (PH). In the serum, galactosamine caused elevation of conjugated bile acids such as taurocholic acid (TCA) and tauro-beta-muricholic acid (T beta MCA) at the 24 and 48-h time points, whereas unconjugated bile acids including cholic acid (CA) at 24 h and hyodeoxycholic acid (HDCA) at 48 h were increased after PH. In the bile, elevation of TCA showed most remarkable elevation at the 24-h time point in the galactosamine-treated group. All components of biliary bile acids showed rapid decreases from 24 to 48 h. The results demonstrated that while liver tissue damaged by galactosamine is able to conjugate bile acids it allows leakage into the blood stream. In contrast, the results for rats subjected to PH indicated that liver cells during DNA synthesis are not capable of conjugating all free bile acids with taurine although a similar leakage occurs. It is concluded that obvious elevation of serum TCA or CA and biliary T beta MCA could be a useful indicator of hepatocellular proliferation.

Animals↗
PubMed1990

A novel diisopropylphosphofluoridate-sensitive phenylalanine arylamidase in human liver.

A diisopropylphosphofluoridate-sensitive (DFP-sensitive) arylamidase, which preferentially hydrolyzed Phe-p-nitroanilide (Phe-pNA), was purified from a crude extract of human liver by conventional chromatographic techniques. The purified enzyme gave a single band on SDS-polyacrylamide gel electrophoresis. The molecular weight of the enzyme was estimated to be 58,000 by SDS-polyacrylamide gel electrophoresis and 200,000 by chromatography on a column of Sephacryl S-300, suggesting that the enzyme is a trimer or a tetramer. The enzyme was inactivated in proportion to the amount of [3H]DFP incorporated with a [3H]DFP/subunit (58,000) molar ratio of 1.04. The data indicate that the enzyme belongs to the serine protease family.

Amino Acids↗
PubMed1989

Stimulation of rat liver growth by a 1,3-dithiole derivative, KZ-1026.

The oral administration of 2-(1,3-dithiol-2-ylidene)-1-phenyl-1,3-butanedione (KZ-1026) to normal rats at doses of 50, 100 and 200 mg/kg/day for 3 days accelerated liver enlargement in association with a dose-dependent increase in the total amounts of protein, RNA and DNA in the liver. The liver weight at 24 hr after the third dose of 200 mg/kg reached 174% of the control. With respect to the effect on liver enlargement, KZ-1026 differed from phenobarbital, since KZ-1026, unlike phenobarbital, increased hepatic DNA content without significant effects on P-450 and aminopyrine-N-demethylase. Incorporation of [3H]thymidine into liver DNA was stimulated by a single dose of KZ-1026 (200 mg/kg), and it peaked at 24 hr post dose (18 times the control), followed by an increase in the number of liver nuclei. Liver growth was also accompanied by an increasing hepatic reserve cell mass, expressed by the capacity of eliminating exogenous galactose from the blood stream. Pretreatment with KZ-1026 (200 mg/kg/day) for 3 days significantly improved the survival rate of subtotally hepatectomized rats from 39% to 78%. These findings indicate that KZ-1026 accelerates hepatocyte proliferation, resulting in an enhancement of liver functional mass in normal rats.

Animals↗
PubMed1988

Two different molecular pathways account for low IL-2 receptor and c-myc mRNA expression by lpr Lyt-2- L3T4- T cells.

We have previously shown that Lyt-2- L3T4- T cells from the lymph nodes of MRL/lpr/lpr mice could respond to 12-O-tetradecanoylphorbol-2-acetate (TPA) and A23187 by proliferation, IL-2 secretion, and IL-2R (IL-2R) expression. However, the optimal response was significantly less than that of normal T cells. To understand the molecular mechanisms underlying the relatively inert nature of these cells, the expression of the T cell early competence genes, IL-2R and c-myc, was examined by Northern blot analysis and nuclear run-on assays. In resting lpr Lyt-2- L3T4- T cells, IL-2R mRNA was not detected, whereas the expression of c-myc mRNA was slightly enhanced compared to that of normal T cells. TPA and A23187 synergistically induced both IL-2R and c-myc mRNA expression by the lpr Lyt-2- L3T4- T cells, as well as by normal T cells. However, the amounts of specific mRNA induced in the former were much less than those in the latter. Cycloheximide treatment caused the TPA/A23187-stimulated lpr cells to express large amounts of c-myc mRNA, but not IL-2R mRNA. The deficient expression of c-myc and its correction by cycloheximide treatment were also observed in Con A-stimulated lpr Lyt-2- L3T4- T cells. Run-on transcription assays revealed that the enhancing effect of cycloheximide was most likely at the posttranscriptional level. These findings suggest that two separate mechanisms differentiated by their sensitivity to cycloheximide can inhibit the accumulation of mRNA for early competence genes in lpr Lyt-2- L3T4- T cells. These mechanisms may prevent the full activation of the lpr T cells and lead to abnormal differentiation of these cells.

Animals↗
PubMed1988

Bovine endothelial cell plasminogen activator inhibitor. Purification and heat activation.

A plasminogen activator inhibitor (PAI) was purified from bovine endothelial cell conditioned medium by a simple procedure in the absence of protein denaturant. The yield was 2.2 mg from 1.61 conditioned medium in a typical experiment. The purified inhibitor showed a single band on sodium dodecyl sulfate/polyacrylamide gel electrophoresis and reverse fibrin autography with an apparent molecular mass of 45 kDa. The amino-terminal 40-amino-acid sequence was determined and found to be 70% similar to the reported corresponding sequence of human PAI-1. The amino acid composition also revealed a close relationship between bovine PAI and human PAI-1. The purified PAI was substantially inactive (570 U/mg) but it could be activated by treatment with protein denaturants such as 1% SDS (1.8 X 10(5) U/mg) and 4 M guanidine-HCl (1.5 X 10(5) U/mg). A more effective activation of this latent PAI was achieved by heat treatment at 100 degrees C for 2.5 min, generating the specific activity of 1.0 X 10(6) U/mg. The heat-activated PAI lost its activity during incubation at 56 degrees C for 30 min, but repeated heat at 100 degrees C for 2.5 min could regenerate about 70% of the initial activity. Treatment at 37 degrees C, 56 degrees C and 80 degrees C, however, failed to activate the latent PAI at all. These findings suggest that the buried reactive site of the latent PAI is exposed as a result of a heat-induced, specific conformational change, but tends to be masked again during renaturation under mild conditions, i.e. the PAI protein takes on preferentially a latent form.

Amino Acid Sequence↗
PubMed1988

Effect of ursodeoxycholate on the biliary excretion of cefotiam and sulbenicillin in patients with percutaneous transhepatic biliary drainage.

The effects of ursodeoxycholate administration on the biliary excretion of the antibiotics cefotiam and sulbenicillin were studied in five patients with stable hepatic function receiving percutaneous transhepatic biliary drainage for obstructive jaundice. Cefotiam (I g) and sulbenicillin (2 g) were administered intravenously before and after ursodeoxycholate administration, and the maximum concentrations of the antibiotics in the bile and total amounts excreted in the bile during the 4 h after administration were determined. After ursodeoxycholate administration, both the maximum concentration of cefotiam in the bile and the amount excreted increased significantly. Ursodeoxycholate also increased the peak concentration and total excretion of sulbenicillin. For both cefotiam and sulbenicillin, the amount of antibiotic excreted in the bile during the 4 h after administration showed a significant correlation with the amount of bile acids excreted in the bile. This strongly suggests a common mechanism for the biliary excretion of these antibiotics and bile acids. Ursodeoxycholate administration is a benign way to increase both the concentration and the total amount of antibiotic excreted in the bile. Therefore, it may be useful in the treatment of serious biliary tract infections, especially in patients receiving biliary drainage.

Aged↗
PubMed1987

Interleukin 2 responses of lpr and normal L3T4-/Lyt-2- T cells induced by TPA plus A23187.

The major population of cells that accumulate abnormally in MRL/Mp-lpr/lpr lymphoid tissue is Thy-1+, L3T4-, and Lyt-2-. To clarify the functional potential of these cells, we examined their proliferation, interleukin 2 (IL 2) receptor expression, and IL 2 secretion by using as stimulants the combination of 12-O-tetradecanoylphorbol-2-acetate and A23187 (a calcium ionophore). Although the lpr T cells were capable of responding to these stimulants, the nature of the response and of the concentrations of ligand required differed sharply from the responses of normal adult T cells, and of adult L3T4-Lyt-2- thymocytes. There was a strong similarity but not identity when responses of 16 day fetal thymocytes were compared with those of lpr L3T4-Lyt-2- cells. The unusual functional properties of the lpr cells, such as high A23187 dose requirement for maximal proliferation, low percentage of IL 2 receptor-expressing cells, and low levels of IL 2 secretion, suggested that these cells are arrested at a stage of development similar to that of 16-day fetal thymocytes and before adult L3T4-/Lyt-2- thymocytes.

Animals↗
PubMed1987

Age-related changes of the dermatan sulfate containing small proteoglycans in bovine tendon.

Sulfated proteoglycans of fetal, newborn and adult bovine tendon are extracted with neutral salt and then with 4 M guanidine HCl in the presence of proteinase inhibitors. Dermatan sulfate containing small proteoglycans are separated from chondroitin sulfate rich proteoglycans by CsCl-gradient centrifugation, by affinity chromatography using concanavalin A and by molecular sieve chromatography. These proteoglycans are comprised of a core protein with an average Mr of about 53,000 on polyacrylamide gel electrophoresis with SDS and of dermatan sulfate side chains with Mr 25,000-38,000 by gel chromatography. The tryptic peptides patterns observed in the small proteoglycans from newborn calf and adult bovine tendon are identical but are distinct from those of embryonic calf tendon. The patterns of the tryptic peptides of the core proteins from embryonic calf tendon are similar to those from the dermatan sulfate proteoglycans of calf skin. These results indicated that genetically independent genes of the core proteins from dermatan sulfate proteoglycans in tendon tissues were expressed by aging.

Aging↗
PubMed1987

Production of hepatitis B virus surface antigen particles by the human hepatoma cell line huGK-14 in a serum-free medium.

The human hepatoma cell line, huGK-14, containing integrated hepatitis B virus (HBV) DNAs, produced a large number of 23 nm spherical particles of HBV surface antigen (HBsAg) in a serum-free medium. These particles closely resembled the HBsAg particles found in the sera of HBV carriers and elicited a high antibody response in guinea pigs. The huGK-14 cells in a serum-free medium would provide a new, economic source of HBV vaccine.

Antibody Formation↗