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T Kitagawa

Publications and source records attributed to T Kitagawa.

At least 379 records · Page 21Linked to original sources
PubMed1990

Observation of the Fe4+ = O stretching Raman band for cytochrome oxidase compound B at ambient temperature.

Resonance Raman and visible absorption spectra were simultaneously observed for cytochrome oxidase reaction intermediates at 5 degrees C by using the artificial cardiovascular system (Ogura, T., Yoshikawa, S., and Kitagawa, T. (1989) Biochemistry 28, 8022-8027) and a device for Raman/absorption simultaneous measurements (Ogura, T., and Kitagawa, T. (1988) Rev. Sci. Instrum. 59, 1316-1320). The Fe4+ = O stretching (nu FeO) Raman band was observed at 788 cm-1 for compound B for the first time. This band showed the 16O/18O isotopic frequency shift (delta nu FeO) by 40 cm-1, in agreement with that for horseradish peroxidase compound II (nu FeO = 787 cm-1 and delta nu FeO = 34 cm-1). In the time region when the FeII-O2 stretching band for compound A and the nu FeO band for compound B were coexistent, a Raman band assignable to the Fe3+-O-O-Cu2+ linkage was not recognized.

Animals↗
PubMed1990

Resonance Raman study on mutant cytochrome P-450 obtained by site-directed mutagenesis.

Resonance Raman spectra were observed for the threonine-301 to serine or valine mutant as well as the wild type of rabbit liver microsomal cytochrome P-450 [laurate(omega-1)-hydroxylase] (P-450(omega-1], which were prepared through site-directed mutagenesis. The high-spin marker resonance Raman (RR) bands became similarly stronger for all the P-450s examined in the oxidized form upon addition of laurate, and the RR spectra in the higher frequency region of the oxidized, reduced and CO-adduct forms did not distinctly differ among the P-450s examined. Nevertheless, the Fe-CO stretching mode (vFe-CO) of the CO adduct exhibited an upshift for the valine mutant, suggesting positional proximity of Thr-301 to bound CO like Thr-252 of P-450cam, in agreement with the expectation from the sequence analysis. The vFe-CO band was shifted to higher frequency upon binding of normal alkyl fatty acids with C10 or longer alkyl chain but little affected by binding of shorter fatty acids.

Animals↗
PubMed1990

Cytotoxic effects of aflatoxin B1 and its association with cellular components in chicken embryo primary cultured cells.

We have examined the cytotoxicity and cellular incorporation of aflatoxin B1 (AFB1) in several types of established and primary cultured cells. The inhibition of DNA synthesis by AFB1 at 1 microgram/ml was about 0-30% in the established cell lines, including human hepatic cells. In chicken primary hepatocytes, however, DNA synthesis as well as RNA and protein syntheses were strongly inhibited by much lower concentrations of AFB1, e.g., 0.1 microgram/ml. In contrast, chicken primary fibroblasts showed almost no significant response to the toxin. Microsomal cytochrome P-450 activities in hepatic tissues were 10-20-fold higher than those in fibroblastic tissues. The amount of [3H]AFB1 incorporated into acid-insoluble materials in the primary hepatocytes was also 10-100-fold more than that in the primary fibroblasts. However, a significant amount of AFB1, which was enough to induce cytotoxic effects on the primary hepatocytes, could be incorporated into the primary fibroblasts when the concentrations of AFB1 were increased. Characterization of the AFB1-associated cellular components showed that most of them were DNA, RNA, and proteins in the primary hepatocytes, while in the primary fibroblasts a large portion of the incorporated AFB1 was recovered from lipid fractions. In addition, the selective binding of [3H]AFB1 to several proteins was observed only in the primary hepatocytes. The possible role of the AFB1-binding proteins are also discussed.

Aflatoxin B1↗
PubMed1990

A new liquid-phase enzyme immunoassay for rabbit IgM antibodies and its application for comparing the specificity of IgM and IgG antibodies contained in the same antiserum.

A new liquid-phase enzyme immunoassay (EIA) has been developed to compare the specificities of IgM and IgG antibodies when they are both present in the same serum sample and directed towards a simple hapten. The hapten viomycin (VM) was used as the model antigen and antibodies to VM were raised in rabbits. In the immunoassay VM, labelled with the enzyme galactosidase as marker (VM-GAL), was mixed with rabbit anti-VM serum. First IgM anti-VM antibodies bound to VM-GAL were precipitated with a guinea pig anti-rabbit IgM serum and galactosidase activity was measured in the precipitate. Then IgG anti-VM antibodies bound to VM-GAL were precipitated from the supernatant with a goat anti-rabbit IgG serum and enzyme activity was measured in this precipitate. The guinea pig anti-rabbit IgM and goat anti-rabbit IgG were specific for IgM and IgG respectively and did not appear to cross-react. Nine analogues of VM were used as inhibitors in this immunoassay to compare the specificities of IgM and IgG antibodies for determinants on VM. The results suggest that recognition of the fine structure of VM by IgM is less strict than recognition by IgG.

Animals↗
PubMed1990

Diffuse intrasinusoidal metastasis of gastric carcinoma to the liver leading to fulminant hepatic failure. A case report.

An unusual case of gastric carcinoma with diffuse intrasinusoidal metastasis to the liver (DIML) presenting as fulminant hepatic failure is reported. The patient was a 59-year-old man admitted to the hospital complaining of dysphagia. Seven weeks after performance of total gastrectomy, he developed jaundice and consciousness disturbance and died 4 days later. The surgical material was diagnosed as advanced cancer (poorly differentiated adenocarcinoma) of the stomach and postmortem examination disclosed massive and diffuse infiltration of the tumor cells into the hepatic sinusoids with no grossly detectable metastatic nodules. It is important to be aware that, although uncommon, gastric carcinomas may cause fulminant hepatic failure attributable to DIML. The clinicopathologic features of such cases are detailed and a review of the relevant literature included.

Carcinoma↗
PubMed1990

Embryological development and prevalence of digital flexion creases.

The embryological development and morphology of digital flexion creases were studied in 178 human embryos and fetuses 6-20 weeks of gestational age. The results suggest the existence of two types of digital flexion creases, that differ from each other in their development. The regular creases, with the exception of the distal crease of the proximal interphalangeal creases, and the oblique and extra creases of the irregular creases, develop concurrently with the appearance of the digital pads by about 11 weeks of gestation. The remaining creases, i.e., the distal crease of the proximal interphalangeal creases and the accessory crease develop later unrelated to the pads but, apparently, secondary to the flexion movements of the hand. Our observations further suggest that, because of their high frequencies, the oblique creases on the ulnar side of digits I and II and on the radial side of digit V and the extra creases on the proximal phalanx of digits I, III, and IV should be considered as "regular" creases. Previously unreported pads were also found on the middle phalanges at about 11 weeks of gestation. Unlike the single, large pads with high elevation, typically found on the distal phalanges, those on the middle phalanges are multiple, small, and only slightly elevated. This observation provides further support to the concept of the relationship between the fetal digital pads and the development of the epidermal ridge patterns.

Fetus↗
PubMed1990

A highly sensitive enzyme-linked immunosorbent assay for etoposide using beta-D-galactosidase as a label.

A highly sensitive enzyme-linked immunosorbent assay (ELISA) for etoposide (EP) was developed, which is capable of accurately measuring as little as 40 pg EP/ml. Anti-EP sera were obtained by immunizing rabbits with EP conjugated with mercaptosuccinyl bovine serum albumin (MS.BSA) using N-[beta-(4-diazophenyl)ethyl]maleimide (DPEM) as a heterobifunctional coupling agent. An enzyme marker was similarly prepared by coupling EP with beta-D-galactosidase (beta-Gal; EC 3.2.23) via DPEM. This ELISA was specific for EP and showed a very slight cross-reactivity with its major metabolite, cis-hydroxy acid of EP (0.91%), but none with 4'-demethylepipodophyllotoxin and drugs commonly used with EP in combination chemotherapy for cancer treatment. The values for EP concentration detected by this assay were comparable with those detected by the high-performance liquid chromatography (HPLC) method. However, the ELISA was about 1,250 times more sensitive in detecting EP at lower concentrations. Using this assay, drug levels were easily determined in the blood and urine of rats for 7 h after i.v. administration of EP at a single dose of 3 mg/kg. Due to its sensitivity and specificity for EP, the ELISA should prove to be a valuable new tool for use in clinical pharmacological studies.

Animals↗
PubMed1990

Sequential study on spontaneous colony formation by bone marrow cells during butylnitrosourea-induced leukemogenesis in the rat.

The spontaneous colony (SC)-forming activity of bone marrow cells of rats during butylnitrosourea (BNU) treatment was studied sequentially in an attempt to analyze stages of leukemogenesis. Aspirated bone marrow cells from female Sprague-Dawley (SD) rats that had been given continuous access to drinking water containing 400 ppm BNU were examined at intervals of 3-5 weeks for colony formation of granulomonocytic cells with or without supplemental colony-stimulating factor (CSF). Granulocytic leukemia was first observed at week 12, and the cumulative incidence reached 80% by week 30. SCs were obtained in 56% of rats in the early stage (3 weeks) and in up to 59% of rats in the late stages (20-25 weeks). However, in the middle stages colony formation was rare, even with the addition of CSF. When adherent cells were removed from the bone marrow cells, the SC-forming activity in the early stage was almost entirely lost, whereas much of that in the late stage remained. It is possible that in the former case, overproduction of endogenous CSF by adherent cells under the influence of BNU treatment could be involved. In contrast, late stage SC formation may be associated with the generation of altered cells, including leukemic or preleukemic elements, which have increased capacity for autonomous growth. The loss of SC-forming activity in the middle stage appeared to be attributable to an extreme reduction in endogenous CSF due to marked devastation of the bone marrow. Technical improvement in adjusting more precisely the level of CSF in the culture medium is required to enable further analysis of leukemogenesis, focused on the colony-forming activity of target cells.

Animals↗
PubMed1990

Absence of H-ras point mutation at codon 12 in N-methyl-N-nitrosourea-induced hepatocellular neoplasms in the rat.

In order to assess the possibility that activated ras-associated hepatic carcinomas might be much rarer in rats than mice because of the more frequent or rapid occurrence of powerful carcinogenic event(s) other than ras point mutations in the former animals, precancerous lesions and hepatocellular carcinomas induced by a weak hepatocarcinogen N-methyl-N-nitrosourea (MNU) in the rat liver were analyzed for the presence or absence of ras point mutations. MNU was chosen because it is well known that MNU-induced rat mammary carcinomas contain activated H-ras at very high frequency. Male Fisher rats were treated with a single dose of MNU after partial hepatectomy, and then administered dietary phenobarbital or repeated s.c. injections of carbon tetrachloride as promoting procedures. Analyses by oligonucleotide hybridization, MnlI-restriction-fragment-length polymorphism and NIH3T3 cell transfection assays revealed neither H-ras point mutations nor transforming ability of the DNA from 36 MNU-induced rat hepatic neoplasms. The results were in agreement with previous results for rat hepatocellular carcinomas induced by other potent liver carcinogens and did not support our hypothesis that the frequency of finding ras activation might be dependent on the strength of the carcinogen.

Animals↗
PubMed1990

A supernumerary cusp in the human pulmonary valve.

A supernumerary cusp of the valve of the pulmonary trunk was found in a 75-year old, male Japanese. The valve was composed of 4 cusps of different size and shape. The supernumerary cusp was located between the right and left cusps. We found this case from a series of 1,100 consecutive necropsies.

Aged↗
PubMed1990

Metabolic changes following gastroplasty in Prader-Willi syndrome--a case report.

A vertical banded gastroplasty was performed in an adult female patient with Prader-Willi syndrome in an attempt to prevent the metabolic deterioration caused by polyphagia. After her operation, the patient felt satiated with the scheduled amount of food and one month later, her fasting blood sugar concentration (FBS) decreased from 521 to 125 mg/dl, and her urinary sugar excretion (US) from 257 to 9 g/day. Both glucose tolerance and insulin secretion were also improved. However, these parameters subsequently became worse after dietary control was lost since the surgical procedure alone was unable to continue to suppress the insatiable desire to eat food. Both her glucose tolerance and insulin secretion by the 31st postoperative month were better than before the surgery, but worse than at one month after the surgery. At the end of the surgery, but worse than at one month after the surgery. At the end of the 34th postoperative month, even under the temporary administration of 0.625 mg/day of glibenclamide, her FBS was 158 mg/dl and US, 38.1 g/day. Her body weight had also increased to over her preoperative value. Based on these results, we conclude that the effect of gastroplasty to prevent metabolic deterioration in our patient with Prader-Willi syndrome gradually diminishes.

Adult↗
PubMed1990

A case of coexisting malignant carcinoid tumor and adenocarcinoma in the papilla of Vater.

A 47-year-old Japanese woman in whom obstructive jaundice had already been diagnosed, was found to have a dome-shaped elevated tumor approximately 3 cm in diameter located in the area very close to the papilla of Vater on endoscopical and radiographical investigations. Histopathologically, the resected tumor was composed mainly of solid nests of atypical argyrophilic cells, and partially of an area of well differentiated tubular adenocarcinoma, showing mutual transition in the mucosal layer. Both immunohistochemical and ultrastructural analyses confirmed the difference in character of tumor cells between these two areas: neuroendocrine cell carcinoma and tubular adenocarcinoma of common type in the intestine. To the best of our knowledge, this is only the third case reported to be a coexisting malignant carcinoid tumor and adenocarcinoma arising in the periampullary region.

Adenocarcinoma↗
PubMed1990

Development of transgenic mice containing woodchuck hepatitis virus DNA.

We produced transgenic mice containing woodchuck hepatitis virus DNA with tandem repeat structure capable of producing virus and viral antigens. Poly(A)+ RNAs probably corresponding to pregenome and viral antigens were detected in their liver. These mice have now been healthy for one year. However, there is the possibility of inducing immunologically mediated hepatitis. We anticipate these transgenic mice may present a useful model system for studying the significance of chronic hepatitis in hepatocellular carcinoma development.

Animals↗
PubMed1990

Immunogenetics of early-onset insulin-dependent diabetes mellitus among the Japanese: HLA, Gm, BF, GLO, and organ-specific autoantibodies--the J.D.S. study.

The Japan Diabetes Society (JDS) conducted a multicenter study on the immunogenetics of early-onset insulin-dependent diabetes mellitus (IDDM) of the Japanese. Human leukocyte antigen (HLA), properdin factor B (BF), immunoglobulin heavy-chain complex (Gm), and glyoxalase of erythrocytes (GLO) were typed, and organ-specific autoantibodies, including islet cell antibody (ICA), were assayed in 159 Japanese IDDM patients and their family members and in 258 healthy Japanese controls. The HLA-DRw9 phenotype and HLA-Bw61/DRw9 haplotype were significantly increased among the patients with autoantibodies other than ICA but with no autoimmune diseases (RR = 5.84, cP less than 0.001; and RR = 7.45, P less than 0.001), whereas the HLA-DR4 phenotype and HLA-Bw54/DR4 haplotype were significantly increased in those without either the autoantibodies or autoimmune diseases (RR = 2.64, cP less than 0.001; and RR = 4.55, P less than 0.001). The HLA-DR4 phenotype was significantly increased in the patients with autoimmune thyroid diseases (RR = 6.21, cP less than 0.05). In all groups of patients, the HLA-DR2 phenotype was significantly decreased, and the relative risk of the HLA-DRw9/DR4 genotype was highest among all HLA-DR genotypes. No significant association was found between HLA type and the duration or incidence of ICA. Gm types of g and gft were significantly increased in the patients with the autoantibodies (RR = 2.11, P less than 0.05; and RR = 34.11, P less than 0.05), whereas the BF-F phenotype was significantly decreased in the patients either with or without autoantibodies (RR = 0.43, P less than 0.05; and RR = 0.46, P less than 0.05). There was no association between IDDM and GLO type. These data indicate that immunogenetic bases underlying IDDM of the Japanese are heterogeneous, as are those in Caucasians.

Autoantibodies↗
PubMed1990

The A3 allele of the HLA-DQA1 locus is associated with susceptibility to type 1 diabetes in Japanese.

Analysis of the frequencies of class II HLA-DR and HLA-DQ alleles by serological and DNA typing in 49 Japanese patients with type 1 (insulin-dependent) diabetes and 31 Japanese controls indicates the following. (i) Susceptibility is more strongly associated with the HLA-DQ subregion than with the HLA-DR subregion. (ii) Of the class II alleles detected, the A3 allele of the DQA1 locus was the most strongly associated with disease. Ninety-six percent of the patients were positive for the A3 allele compared to 53% of the controls (P = 0.001; relative risk = 19.7; confidence limits = 3.72-188.64). (iii) The DQw8 allele of the DQB1 locus, which is associated with susceptibility to type 1 diabetes in Caucasians and Blacks, was not increased in frequency in Japanese patients (22%) versus controls (19%). (iv) Asp-57-encoding DQB1 alleles are associated with reduced susceptibility to type 1 diabetes in Caucasians. The major predisposing haplotypes in Japanese are DR4 and DR9. By DNA sequence analysis, both of these Japanese haplotypes have Asp-57-encoding DQB1 alleles. Oligonucleotide dot blot analysis showed that all, except 1, of the 49 Japanese patients and all of the 31 controls have at least one Asp-57-encoding DQB1 allele. In addition, 40% of the patients were homozygous for Asp-57-encoding DQB1 alleles versus 35% of the controls. The high frequencies of Asp-57-encoding DQB1 alleles in this ethnic group may account for the rarity of type 1 diabetes in Japan.

Alleles↗
PubMed1990

Detection of activated c-H-ras oncogene in hepatocellular carcinomas developing in transgenic mice harboring albumin promoter-regulated simian virus 40 gene.

Hepatocellular carcinomas (HCCs) developing in transgenic mice harboring an albumin promoter-regulated simian virus 40 (SV40) tumor antigen gene were analyzed for activating point mutations of the c-H-ras oncogene. Oligonucleotide hybridization studies utilizing enzymatically amplified DNA sequences of paraffin-embedded tumor tissues revealed that 10 out of 25 HCCs contained either an A-to-T or an A-to-G conversion at the second position of codon 61. Northern blot studies confirmed expression of SV40 gene mRNAs in the tumor tissues of both mutation-positive and mutation-negative HCCs. These findings in association with earlier results thus strongly suggest that mutational activation of cellular oncogene may play an important role in SV40-initiated multistage hepatocarcinogenesis in vivo.

Albumins↗
PubMed1990

Red and blue distinctive mucin-histochemical types of Japanese colorectal mucosa.

Mucin-histochemical characteristics of normal human colorectal mucosa were investigated utilizing Culling et al.'s staining method which distinguishes the mode of C8-O-acylation of sialomucins. Normal mucosae of cecum, ascending, transverse and descending colon and rectum were obtained from autopsy and biopsy material. Japanese colorectal mucosa stained either entirely red or entirely blue, in contrast to previous reports dealing with Caucasians where all the normal mucosa reportedly stained red. The ratio of red to blue colon cases varied to some extent with age, i.e. it was found to be 1:1 in children aged 0 to 4, 2:1 in the 5-20 age group, and 4:1 in people older than 21 years, suggesting a tendency of shift from blue to red during early life in Japan. Each individual Japanese adult colorectal mucosa may thus be classified into either red or blue type mucin-histochemically.

Adolescent↗