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Biomedical subjects

K Yagi

Publications and source records attributed to K Yagi.

At least 433 records · Page 24Linked to original sources
PubMed1990

Characterization of immobilized hepatocytes as liver support.

Hepatocytes isolated from rat liver were immobilized within Ca-alginate. Immobilized hepatocytes could remove ammonia and other toxic substances causing hepatic coma, such as indole, phenol, bilirubin, and short chain fatty acids. Although free hepatocytes lost those activities within 2 days, immobilized hepatocytes maintained those activities for more than 7 days. Immobilized hepatocytes induced tyrosine aminotransferase (TAT) in the presence of dexamethasone and dibutyryl-cAMP and retained the ability to induce TAT for more than 7 days. Biologically active form of coagulation factor II, prothrombin could be synthesized and secreted into medium by immobilized hepatocytes. Moreover, immobilized hepatocytes produced glucose from lactate, alanine, fructose, and galactose. Like adult rat liver, growth-related function and liver-specific function in immobilized hepatocytes were reciprocally controlled by cell density. There are both alpha-, and beta-adrenergic receptors in membrane of liver cells, and the adrenergic action of epinephrine is alpha-predominant in adult rat liver. Monolayer-cultured hepatocytes can not maintain alpha-adrenergic response. However, immobilized hepatocytes maintained alpha-adrenergic response as shown in vivo. Those characteristics of immobilized and three-dimensionally cultured hepatocytes are regarded almost the same as liver cells in vivo. Furthermore, therapeutic effect of immobilized hepatocytes on the hepatic failure were confirmed in the experiment using hepatocytes damaged with D-galactosamine. Therefore, it is suggested that immobilized hepatocytes could be applied to a hybrid artificial liver support.

Alginates↗
PubMed1990

Effect of linoleic acid hydroperoxide on adenovirus DNA replication.

The effect of linoleic acid hydroperoxide on replication of adenovirus type 2 DNA in HeLa cells was examined. The level of the DNA was extremely reduced when the cells immediately after the infection with adenovirus type 2 were incubated for 24 h in the presence of 1 nmol/ml (measured by the thiobarbituric acid reaction and expressed in terms of malondialdehyde) of the hydroperoxide. The levels of the messenger RNA for adenovirus type 2 DNA polymerase and the expressed polymerase were equally reduced. The inhibition of DNA replication by lipid hydroperoxides in animal cells was discussed in relation to degenerative disorders.

Adenoviruses, Human↗
PubMed1990

Feasibility of subclassification of temporal lobe epilepsy (1989): an etiological overview.

Temporal lobe epilepsy with amygdalohippocampal seizures may have episodes of severe convulsions in childhood more frequently and the onset age is significantly lower compared to epilepsy with lateral temporal seizures. To the contrary, tumorous lesions are found more frequently in epilepsy with lateral temporal seizures. In view of the presumed known etiologies in relation to the localization of epileptogenic foci, the Classification of Epileptic Syndrome (1989), subdividing temporal lobe epilepsies into 2 groups, was found to be useful.

Adult↗
PubMed1990

[In vitro immunoglobulin synthesis by peripheral blood mononuclear cells from patients with myasthenia gravis].

In vitro immunoglobulin (Ig) synthesis was studied using peripheral blood mononuclear cells (PBM) from 12 patients with myasthenia gravis (MG). In cultured PBM, levels of secreted IgG, IgM and IgA measured by ELISA, as well as the number of IgG-, IgM-, and IgA-secreting cells determined by reversed plaque assay, were higher in MG than in controls; this was not dependent upon the stimulation of PBM with pokeweed mitogen (PWM). PBM from 9 of 12 MG patients synthesized anti-acetylcholine receptor (AChR) antibodies in vitro in the presence of PWM, while PBM from 7 controls did not. Patients whose PBM secreted lower levels of each Ig class also secreted fewer or no anti-AChR antibodies. Levels of anti-AChR antibodies secreted in vitro showed a high degree of correlation with titers of sera from patients (r = 0.86). The results suggest that the process of anti-AChR antibody synthesis by PBM in vitro is related to that of Ig synthesis, and that PBM plays, at least in part, an important role in the production of anti-AChR antibodies in MG.

Adult↗
PubMed1989

[Clinical evaluation of serum CA130 in patients with lung cancer].

CA130 is a glycoprotein which is recognized by monoclonal antibodies-(130-22 and 145-9) produced by immunization with human lung adenocarcinoma cell line (PC-9). CA130 is considered to be a new tumor marker, different from CA125, since it has a separate antigenic determinant. We used the D-7111 kit (Daiichi Radioisotope Laboratories, Ltd.) to measure the serum level of CA130 in 290 patients with lung cancer, 171 patients with noncancerous lung disease (N-CLD) and 93 healthy adults. In addition, CEA, CA19-9, CA125 and sialyl SSEA-1 antigen (SLX) were also measured for the same serum samples when possible. The cutoff level for CA130 was 35 U/ml. The overall positive rates for CA130 were 32% in the lung cancer patients, 23% in the N-CLD patients and 0% in the healthy adults. The positive rate in the lung cancer patients was significantly higher than in the N-CLD patients (p less than 0.05). As a function of the histological type of lung cancer, the positive rates for CA130 were 44% in 120 patients with adenocarcinoma, 17% in 115 patients with squamous cell carcinoma, 33% in 36 patients with small cell carcinoma, 42% in 12 patients with large cell carcinoma and 29% in 7 patients with miscellaneous cell type. The positive rate in the patients with adenocarcinoma was significantly higher than in the patients with squamous cell carcinoma (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1989

113Cd-NMR evidence for cooperative interaction between amino- and carboxyl-terminal domains of calmodulin.

113Cd-NMR experiments were performed to characterize the nature of Cd2+ binding to calmodulin in the presence of a tetradecapeptide mastoparan or a 26-residue peptide M13 (calmodulin-binding region of skeletal muscle myosin light-chain kinase). The results indicate that binding of these peptides to calmodulin induces a positive cooperativity between Ca2+ binding to C- and N-terminal domains. The results imply that the activation of myosin light-chain kinase caused by the increase in Ca2+ concentration occurs as a result of cooperative interactions not only between two Ca2+ binding sites in each domain but also between the two domains. The interdomain interaction manifests itself only in the presence of such peptides.

Animals↗
PubMed1989

[Evaluation of sialyl SSEA-1 antigen in patients with lung cancer].

Stage-specific embryonic antigen-1 (SLX) is a glycolipid recognized by a monoclonal antibody (FH 6) which is produced by cells immunized with mice teratocarcinoma cell line. Using an SLX (Otsuka) kit from Ostuka Assay Laboratory, we measured the serum level of SLX in 96 patients with lung cancer, 305 patients with non-cancerous lung disease and 86 healthy adults, prospectively. When we adopted a cutoff level of 42U/ml (mean + 2S.D. in the healthy adults), the overall positive rates were 29.2% in the lung cancer patients, 15.1% in the non-cancerous patients and 0% in the healthy adults. The positive rate of the lung cancer patients was significantly higher than in the patients with non-cancerous lung disease (p less than 0.05). According to the histological type of lung cancer, the positive rates were 40.9% in 44 patients with adenocarcinoma, 18.4% in 37 patients with squamous cell carcinoma, 0% in 7 patients with small cell carcinoma, and 0% in 3 patients with large cell carcinoma. Staging of the lung cancer patients revealed positive rates for serum SLX of 5.6% in 18 stage I patients, 22.2% in 9 stage II patients, 33.3% in 21 stage IIIA patients, 33.3% in 27 stage IIIB patients, 42.9% in 21 stage IV patients. After we performed the immunostaining method for SLX using FH6, positive immunoactivity was demonstrated mainly in the cell membrane of adenocarcinoma cells. SLX seems to be a tumor-associated marker in patients with lung adenocarcinoma.

Adenocarcinoma↗
PubMed1989

Purification of ATP diphosphohydrolase from bovine aorta microsomes.

ATP diphosphohydrolase (EC 3.6.1.5) hydrolyzes pyrophosphate bonds of nucleoside di- and triphosphates in the presence of divalent cations. We purified the enzyme from the vessel wall of bovine aortas. The procedure gave a homogeneous preparation of ATP diphosphohydrolase for the first time from an animal source. Bovine aorta microsomes were treated with 50 mM bicarbonate buffer (pH 10.0) containing 0.025% Triton X-100. The enzyme was then solubilized from the microsomes with 0.5% Triton X-100 and purified to homogeneity by DEAE-Sepharose CL-6B chromatography and 5'AMP-Sepharose 4B affinity chromatography. The apparent molecular mass of the pure enzyme was 110 kDa. The activity recovered was 6% of that of the microsomes. The enzyme was more active with Ca2+ than Mg2+. The sensitivity of ADPase activity to divalent cations was higher than that of ATPase activity. The enzyme had broad substrate specificity to nucleoside di- and triphosphates.

Animals↗
PubMed1989

Expression of the mutant gene for L-gulono-gamma-lactone oxidase in scurvy-prone rats.

A mutant strain of Wistar rats with L-gulono-gamma-lactone oxidase deficiency has recently been established. To investigate this deficiency by DNA and RNA blot hybridization analyses, a fragment of a previously cloned cDNA encoding rat L-gulono-gamma-lactone oxidase was used as a probe. When genomic DNA of the mutant rat was digested with several restriction enzymes, the probe hybridized to fragments of the same sizes as those produced from DNA of normal rats. Poly(A)+RNA from the liver of the mutant rat was found to contain an L-gulono-gamma-lactone oxidase-specific mRNA of a normal size at a comparable level to that of normal rats. An in vitro translation experiment revealed that the mRNA programmed the synthesis of an enzyme protein which had the same molecular weight as that of the translational product of the normal mRNA, although the amount synthesized was markedly reduced as compared with that synthesized with the normal mRNA. In accordance with this observation, a very low but definite degree of L-gulono-gamma-lactone oxidase activity was detected in the microsomes of the mutant rat by a newly developed, highly sensitive method.

Animals↗
PubMed1989

Adriamycin entrapped in sulfatide-containing liposomes.

Sulfatide-containing liposomes composed of PC, cholesterol, and sulfatide in a molar ratio of 7:2:1 entrapped ADM most efficiently among the negatively-charged liposomes tested. A unilamellar vesicle entrapped 123 ADM molecules, of which 6 molecules are localized in the internal space of the vesicle, 4 molecules are embedded into the membrane matrix, and 113 molecules are bound to the inner surface of the liposomal membrane. Highly efficient entrapment of ADM by the liposomes seems to be due to their rigidity. By the experiment using ovarian tumor-bearing nude mice, it was found that the liposome-entrapped ADM was maintained at much higher blood level, at lower concentration in the heart, and at higher concentration in the tumor than the free drug. The antitumor activity of the liposome-entrapped ADM was comparable with that of the free drug. The body weight of the animals was not affected by the former, whereas it was drastically decreased by the latter.

Adenocarcinoma↗