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Biomedical subjects

T Kitagawa

Publications and source records attributed to T Kitagawa.

At least 559 records · Page 31Linked to original sources
PubMed1985

Resonance Raman study on photoreduction of cytochrome c oxidase: distinction of cytochromes a and a3 in the intermediate oxidation states.

Occurrence of photoreduction of bovine cytochrome c oxidase was confirmed with the difference absorption spectra and oxygen consumption measurements for the enzyme irradiated with laser light at 406.7, 441.6, and 590 nm. The resonance Raman spectra were obtained under the same experimental conditions as those adopted for the measurements of oxygen consumption and difference absorption spectra. The photoreduction was more effective upon irradiation at shorter wavelengths and was irreversible under anaerobic conditions. However, upon aeration into the cell, the original oxidized form was restored. It was found that aerobic laser irradiation produces a photo steady state of the catalytic dioxygen reduction and that the Raman scattering from this photo steady state probes cytochrome a2+ and cytochrome a3(3)+ separately upon excitations at 441.6 and 406.7 nm, respectively. The enzyme was apparently protected from the photoreduction in the spinning cell with the spinning speed between 1 and 1500 rpm. These results were explained satisfactorily with the reported rate constant for the electron transfer from cytochrome a to cytochrome a3 (0.58 s-1) and a comparable photoreduction rate of cytochrome a. The anaerobic photoreduction did give Raman lines at 1666 and 214 cm-1, which are characteristic of the ferrous high-spin cytochrome a3(2)+, but they were absent under aerobic photoreduction. The formyl CH = O stretching mode of the a3 heme was observed at 1671 cm-1 for a2+a3(2)+CO but at 1664 cm-1 for a2+a3(2)+CN-, indicating that the CH = O stretching frequency reflects the pi back-donation to the axial ligand similar to the oxidation state marker line (v4).

Animals↗
PubMed1985

Adult T-cell leukemia in two siblings. Acute crisis of smoldering disease in one patient.

Two cases of human T-cell leukemia virus (HTLV)-positive adult T-cell leukemia (ATL) in brother and sister are presented. Six of 15 members of this family were seropositive for antibodies for ATL-associated antigens (ATLA). The sister of the ATL patient developed overt ATL after 5 years and 8 months of smoldering ATL. Immunologic examinations during the smoldering phase were normal except for negative skin tests for purified protein derivative. Factors leading to the induction of ATL among HTLV carriers remain to be studied.

Acute Disease↗
PubMed1985

Resonance Raman spectra for catalytic intermediates of cytochrome c oxidase detected with a mixed flow transient apparatus.

A novel technique was employed to collect resonance Raman spectra of an oxygenated intermediate of cytochrome c oxidase. Instead of laser pulses of high peak power, which may cause photodissociation, a continuous wave laser and a mixed flow apparatus were used. An intermediate formed within 450 microseconds after the reaction of cytochrome c oxidase with molecular oxygen could be detected. From the spectra it could be deduced that the most likely candidate for the intermediate would be a transient oxygenated species having the Fe2+ - O2 or Fe4+ = O heme in cytochrome a3 and the Fe2+ heme in cytochrome a.

Animals↗
PubMed1985

A new solid support for sandwich enzyme immunoassays of human immunoglobulin G.

Two antibodies were prepared for use in a sandwich enzyme immunoassay of human IgG. Completely purified guinea pig anti-human IgG was labelled with beta-D-galactosidase (EC 3.2.1.23), using a heterobifunctional cross-linker named GMBS. Partially purified anti-human IgG was immobilized on a new solid support: Amino-Dylark balls. Optimal conditions for immobilizing the antibody, using glutaraldehyde as the coupling reagent, were studied in detail. With the enzyme-labelled antibody and the solid-phase anti-human IgG, a sandwich enzyme immunoassay of human IgG with a lower limit of detection at 10.5 pM (0.3 ng/tube) was developed. A comparative study of the EIA method and a laser nephelometric method showed a good correlation. The specificity of the assay was excellent: all 4 types of IgG tested showed the maximum 0.0001%; human IgA, IgM and albumin possessed the maximum 0.54% in their cross-reactivity values with human IgG.

Animals↗
PubMed1985

Cloning and the nucleotide sequence of rat glutathione S-transferase P cDNA.

A cDNA library prepared from poly(A)+ RNA of 2-acetylaminofluorene (AAF) induced rat hepatocellular carcinoma was screened by synthetic DNA probes deduced from a partial amino acid sequence of glutathione S-transferase P subunit that had been isolated from the tumor by two-dimensional gel electrophoresis. One of the four clones analyzed contained an mRNA region encoding the total amino acid sequence of this enzyme subunit and the complete 3'-noncoding region. The nucleotide sequence indicates that this enzyme subunit has 209 amino acids (calculated Mr=23,307) distinct from other glutathione S-transferase subunits such as Ya and Yc. Comparison of the amino acid sequences between these proteins indicates that glutathione S-transferase P subunit gene has been evolved from the ancestral gene at an earlier stage than the separation of Ya and Yc and that there are at least three domains having a considerable homology with each other in these enzymes. The very large increase of this mRNA in chemically induced hepatocellular carcinoma suggests a characteristic derepression of this gene during hepatocarcinogenesis.

Amino Acid Sequence↗
PubMed1985

Anticancer drug screening test with LDH in nude mouse bearing bone and soft part sarcoma.

With the use of human LDH as a marker, growth and remission of four human osteosarcomas (KOS-1, KOS-2, KOS-3, OST) and a malignant fibrous histiocytoma (KMF) transplanted into nude mice were monitored during chemotherapies (Adriamycin [doxorubicin], cisplatin, mitomycin C, cyclophosphamide and vincristine). Four osteosarcomas were effectively treated with Adriamycin and cisplatin, and KMF was treated with Adriamycin, cisplatin, and mitomycin C. Changes in human LDH levels paralleled changes in tumor size and these could be used to predict the death of the animals due to tumor (P less than 0.01). Furthermore, the enzyme increased transiently after administration of the effective drugs.

Animals↗
PubMed1985

Reciprocal effects of phenothiazines and naphthalene sulfonamides on the external ATP-dependent permeability change in Chinese hamster ovary cells.

External ATP causes a great increase in passive permeability to phosphorylated metabolites in several transformed cells, but not in untransformed cells. We have previously demonstrated that the external ATP-dependent permeability change was induced in Chinese hamster ovary cells, CHO-K1, only in the presence of a mitochondrial inhibitor (rotenone, KCN) or a cytoskeleton-attacking agent, vinblastine (Kitagawa, T. and Akamatsu, Y. Biochim. Biophys. Acta 649, 76-82 (1981); 734, 25-32 (1983]. A similar ATP-dependent permeability change was also induced in CHO cells when the cells were treated with 10-30 microM trifluoperazine. This permeability change, like the previously mentioned ones, was found to be reversible and the treated cells remained viable. The permeability change induced by ATP and trifluoperazine was independent of changes in cellular ATP concentration and this property was the same as that of the permeability change with external ATP and vinblastine. Since trifluoperazine is known to interact with calmodulin and to inhibit calmodulin-dependent cellular functions, these results may indicate that calmodulin associated with the cytoskeleton plays an important role in control of the permeability change, although nonspecific perturbation by the drug of the membranes cannot be ruled out. Chlorpromazine and a naphthalene sulfonamide, W-7, also induced an ATP-dependent permeability change. However, these drugs, like mitochondrial inhibitors, reduced the cellular ATP concentration to induce the permeability change. Thus, a clear difference in the action of these drugs in intact cells was also shown in this study. Possible mechanisms for the ATP-dependent permeability change in mammalian cells are discussed.

Adenosine Triphosphate↗
PubMed1985

Relationship between serum and histochemical markers for hepatitis B virus and rate of viral integration in hepatocellular carcinomas in Japan.

The relationship between serological and histochemical markers of hepatitis B virus (HBV) and viral integration in hepatocellular carcinomas (HCCs) in Japan was investigated. Special attention was paid to the exclusion of false-positive results due to bacterial contamination of autopsy materials. Of 85 patients with HCC, 23 were positive for serum HBsAg, 18 were positive for serum HBV antibodies and the remaining 44 were negative for serum HBV markers. Among the 23 HCCs from HBsAg carriers, 19 (82.6%) had integrated HBV DNA in the tumor DNA. In contrast, of the 18 HCCs from HBV antibody-positive patients, only one was positive for HBV DNA integration; this particular HCC was from a long-term HBsAg carrier who became a non-carrier by seroconversion at a later age. Of 44 HCCs from patients negative for serum HBV markers, 3 had integrated HBV DNA. Of these 3 cases, 2 were, however, histochemically positive for HBsAg in non-cancerous portions of the liver. Thus, our present results show a high integration rate of HBV DNA in HCCs of carrier patients and an extremely low rate of viral integration in HCCs of non-carrier patients. The latter finding contrasts strongly with previous results gained from analysing materials from patients in Europe and Africa. No histological differences were apparent between HCCs with or without viral integration.

Antibodies, Viral↗
PubMed1985

Sensitive enzyme immunoassay for the quantification of aclacinomycin A using beta-D-galactosidase as a label.

A sensitive enzyme immunoassay method (EIA) for an anticancer drug, aclacinomycin A (ACM), has been developed. With a double-antibody technique, ACM at a concentration as low as 100 pg/tube can be detected. An antibody to ACM was obtained by immunizing rabbits with an antigen prepared by coupling ACM with mercaptosuccinylated bovine serum albumin via N-maleoyl aminobutyric acid (MABA) as a coupling agent. Enzyme labeling of ACM was performed with beta-D-galactosidase (beta-Gal; EC 3.2.1.23) via m-maleoyl benzoic acid (MBA). The standard curve of the assay was linear on a logit-log plot over a concentration range of 30 pg to 10 ng. The antibody detected ACM and its metabolites, MA144 M1 (M1), MA144 N1 (N1), MA144 S1 (S1), and aklavin (T1) equally well, but was only minimally reactive with aklavinone (D1) and 7-deoxyaklavinone (C1), thus suggesting that this EIA can detect the total amounts of ACM and its biologically active glycosides among metabolites of ACM. This EIA is practically free from interference by any other anticancer drugs. Using this assay, serum levels of ACM equivalents can be determined accurately after administration of the drug to rats at a single dose of 10 mg/kg. Since ACM is now undergoing clinical trial, the EIA of the drug will be a valuable tool in clinical pharmacological studies.

Aclarubicin↗
PubMed1985

Annulate lamellae of the jejunal absorptive cells in 21-day-starved rats.

The ultrastructure of annulate lamellae of the jejunal absorptive cells in control and 21 d starved rats was investigated. Annulate lamellae were only rarely encountered in the jejunal absorptive cells of control rats, and then frequently in small stacks continuous with the rough-surfaced endoplasmic reticulum. In contrast, there was a relatively frequent incidence of annulate lamellae in the jejunal absorptive cells of 21 d starved rats, and larger stacks of annulate lamellae were also observed in spite of marked ultrastructural changes of these cells. The annulate lamellae were also continuous with the rough-surfaced endoplasmic reticulum, which was degenerating. The degenerative process of the absorptive cells following starvation might be related to the origin and function of the annulate lamellae.

Animals↗