Biomedical subjects

T Kitagawa

Publications and source records attributed to T Kitagawa.

At least 343 records · Page 19Linked to original sources

PubMed1991

Unusual CO bonding geometry in abnormal subunits of hemoglobin M Boston and hemoglobin M Saskatoon.

To clarify the role of the proximal histidine (F8-His), distal His (E7-His), and E11 valine (E11-Val) in ligand binding of hemoglobin (Hb), we have investigated the resonance Raman (RR) spectra of the carbon monoxide adduct of Hbs M (COHb M) in which one of these residues was genetically replaced by another amino acid in either the alpha or beta subunit. In the fully reduced state, all Hbs M gave v3 at approximately 1472 cm-1 and vFe-His at 214-218 cm-1, indicating that they have a pentacoordinate heme and the heme iron is bound to either E7-His or F8-His. The porphyrin skeletal vibrations of the COHb M were essentially unaltered by replacements of E7- or F8-His with tyrosine (Tyr) and of E11-Val by glutamic acid (Glu). The vCO, vFe-CO, and delta Fe-C-O frequencies of COHb M Iwate (alpha F8-His----Tyr), COHb M Hyde Park (beta F8-His----Tyr), and COHb M Milwaukee (beta E11-Val----Glu) were nearly identical with those of COHb A. In contrast, the RR spectra of COHb M Boston (alpha E7-His----Tyr) and COHb M Saskatoon (beta E7-His----Tyr) gave two new Raman bands derived from the abnormal subunits, vFe-CO at 490 cm-1 and vCO at 1972 cm-1, in addition to those from the normal subunits at 505 cm-1 (vFe-CO) and 1952 cm-1 (vCO). The CO adduct of the abnormal subunits exhibited apparently no photodissociation upon illumination of CW laser with a stationary cell under which the normal subunit exhibited complete photodissociation.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗

PubMed1991

High-energy proton beam radiation therapy for gynecologic malignancies. Potential of proton beam as an alternative to brachytherapy.

Fifteen patients with advanced gynecologic malignancies were treated with high-energy proton beam radiation therapy (RT) at the Particle Radiation Medical Science Center (PARMS), Tsukuba University, Japan, from 1983 to 1987. The potential of proton beam RT as an alternative to conventional brachytherapy was evaluated. Except for one local recurrence, 14 of 15 patients were locoregionally controlled for 15 to 57 months. Two-year local control rate and 2-year survival rate were 92.3% and 93.3%, respectively. Two cases of transient, radiation-induced proctitis (neither of which required surgical treatment) were the only complications despite a target dose that exceeded 8000 cGy in most cases. The results suggest that sharply localized, high-dose proton beam RT can produce an antitumor effect equivalent to that of conventional brachytherapy.

Aged↗

PubMed1991

Strain specific sensitivity to diethylnitrosamine-induced carcinogenesis is maintained in hepatocytes of C3H/HeN in equilibrium with C57BL/6N chimeric mice.

The C3H/HeN (C3H) and C57BL/6N (C57) mouse strains are known, respectively, for their high and low susceptibility to both spontaneous and chemically induced hepatocarcinogenesis. The present study was aimed at elucidating whether this difference is dependent on intrinsic features of the target hepatocytes or in the in vivo milieu and associated growth promoting factors to which the cells are exposed. C3H in equilibrium with C57 chimeric mice were produced and given injections of diethylnitrosamine (20 microgram/g body weight) at the age of 15 days. The animals were sacrificed 6 or 9 months thereafter, and the numbers and sizes of altered cell lesions were scored. The clonal growth of both cell types was immunohistochemically confirmed using anti C3H-specific antigen antibodies. Quantitative assessment revealed C3H lesions in the chimera livers to be far larger (5:1) than those of C57 derivation and associated with more frequent malignant progression as was evident histologically. Furthermore, foamy change and hyalin body formation, which have been described as characteristics of C3H and C57BL hepatic tumors, respectively, were also featured as differentiative characteristics in lesions of both cell types in chimera mice. Thus, the results clearly demonstrated that the principal mechanism(s) underlying strain difference in diethylnitrosamine-initiated hepatocarcinogenesis exists in the target cells and is not milieu-dependent.

Animals↗

PubMed1991

Rapid method for preparing a beta-glucan-specific sensitive fraction from Limulus (Tachypleus tridentatus) amebocyte lysate.

By separating Limulus amebocyte lysate by cation-exchange chromatography with an SP-Toyopearl 650C column, a fraction insensitive to endotoxin, yet specifically sensitive to beta-glucan, was successfully obtained in the unadsorbed portion. This fraction showed beta-glucan dose-dependent clotting enzyme activity, although no sensitivity to endotoxin. This beta-glucan-dependent reaction showed no interference in the presence of endotoxin, with the fraction also showing sensitivity towards various kinds of beta-glucan, i.e. curdlan, pachyman, laminaran and lichenan. The sensitivity towards curdlan was approximately 10(-10) g/ml.

Animals↗

PubMed1991

Observation of the O-O stretching Raman band for cytochrome P-450cam under catalytic conditions.

Dioxygen stretching (voo) Raman band was observed for the oxy form of Pseudomonas putida cytochrome P-450 (P-450cam) generated at room temperature under catalytic conditions, that is, in the presence of D-camphor, beta-NADH, putidaredoxin, and putidaredoxin reductase, by using the mixed flow transient Raman apparatus. At the same time the visible absorption spectra were monitored for the transient species. It was found that the voo frequency is little altered by binding of putidaredoxin to P-450cam, although the reduction rate of the oxy form becomes faster. Another intermediate with an oxygen isotope-sensitive band was not found in a time region until 2 s after mixing of the reduced enzyme with oxygen.

Camphor 5-Monooxygenase↗

PubMed1991

Site-directed mutagenesis in haemoglobin. Functional role of tyrosine-42(C7) alpha at the alpha 1-beta 2 interface.

To clarify the functional role of Tyr-42(C7) alpha, which forms a hydrogen bond with Asp-99(G1) beta at the alpha 1-beta 2 interface of human deoxyhaemoglobin, we engineered two artificial mutant haemoglobins (Hb), in which Tyr-42 alpha was replaced by Phe (Hb Phe-42 alpha) or His (Hb His-42 alpha), and investigated their oxygen binding properties together with structural consequences of the mutations by using various spectroscopic probes. Like most of the natural Asp-99 beta mutants, Hb Phe-42 alpha showed a markedly increased oxygen affinity, a reduced Bohr effect and diminished co-operativity. Structural probes such as ultraviolet-region derivative and oxy-minus-deoxy difference spectra, resonance Raman scattering and proton nuclear magnetic resonance spectra indicate that, in Hb Phe-42 alpha, the deoxy T quaternary structure is highly destabilized and the strain imposed on the Fe-N epsilon (proximal His) bond is released, stabilizing the oxy tertiary structure. In contrast with Hb Phe-42 alpha, Hb His-42 alpha showed an intermediately impaired function and only moderate destabilization of the T-state, which can be explained by the formation of a new, weak hydrogen bond between His-42 alpha and Asp-99 beta. Spectroscopic data were consistent with this assumption. The present study proves that the hydrogen bond between Tyr-42 alpha and Asp-99 beta plays a key role in stabilizing the deoxy T structure and consequently in co-operative oxygen binding.

Hemoglobins↗

PubMed1991

Role of activated c-H-ras oncogene in the induction and progression of immortal liver epithelial cell lines derived from normal C3H mice.

The nature of 15 immortal mouse liver epithelial cell (MLEC) lines established from normal C3H mice was investigated specifically in terms of ras oncogene activation. Neither transforming activity nor point mutation within codon 61 of c-H-ras could be demonstrated in any of the cell lines by DNA transfection in a NIH/3T3 cell system or by the direct sequencing method after polymerase chain reaction, respectively. Acrylamide gel migration analysis of ras p21 products did not show any shift from the normal. Transplantation experiments demonstrated only 2 out of the 15 lines to be tumorigenic in nude mice. When 4 of the non-tumorigenic MLEC lines were transfected with cloned activated c-H-ras containing a point mutation within codon 61, they all became tumorigenic, the resultant neoplasms being hepatocellular carcinomas often associated with albumin mRNA expression. Our results thus indicate that ras activation is not necessary for immortalization or even for transformation of mouse liver cells in culture, and that ras activation may be an event during the progression process in mouse hepatocarcinogenesis in vivo.

Animals↗

PubMed1991

Allelotype study of primary hepatocellular carcinoma.

Accumulation of mutations in oncogenes and tumor suppressor genes transforms a normal cell to a malignant cell by allowing it to escape from normal control of growth. In order to learn (a) how many tumor suppressor genes are involved in the tumor progression of hepatocellular carcinoma, (b) whether there is any association among allelic losses of chromosomes, or (c) whether integration of hepatitis B virus into host DNA influences any particular chromosomal losses, we have examined loss of heterozygosity with 44 restriction fragment length polymorphism markers in 46 cases of hepatocellular carcinoma. The markers represented all chromosomal arms except 5p, 8p, 9p, 18p, and acrocentric chromosomes. Allelic losses in tumors indicated that five tumor suppressor genes, located on chromosomes 5q, 10q, 11p, 16q, and 17p, may be involved in this cancer. However, no significant associations were observed among the various allelic losses or between the integration of hepatitis B virus and chromosomal losses. Furthermore, a deletion map for chromosome 16q indicated the localization of a tumor suppressor gene between q22 and q24 and that for chromosome 17p suggested the existence of a second tumor suppressor gene in addition to the p53 gene.

Alleles↗

PubMed1991

Retrospective survey of urea cycle disorders: Part 1. Clinical and laboratory observations of thirty-two Japanese male patients with ornithine transcarbamylase deficiency.

In a retrospective survey done from 1978-1988 in Japan, 32 male patients with ornithine transcarbamylase (OTC) deficiency were identified. We classified a neonatal and 2 late-onset groups, depending on clinical manifestations and the age at onset; group 1 (0-28 days; N = 10), group 2 (29 days-5 years; N = 13), and group 3 (greater than 5 years; N = 9). Compared to findings in the group 2 patients, there was a higher rate of mortality and a higher incidence of mental retardation in association with a great decrease in enzyme activity in group 1. In group 3, the mortality rate and enzyme activities were similar to those in group 1. However, patients in this group were asymptomatic prior to the first episode. Enzyme activities were measured mostly in autopsy samples. The serum citrulline levels (enzyme product) were highest in this group. Thus, the mutant enzymes were apparently labile with greater activities in vivo than in vitro. Treatments, including a protein-restricted diet, arginine supplementation, and sodium benzoate administration, resulted in a favorable prognosis for survivors with partial enzyme deficiency. We wish to emphasize that the incidence of late onset of this disease is higher than heretofore considered.

Child, Preschool↗

PubMed1991

Recurrent valvular pneumoperitoneum caused by a minute gastric ulcer--a case report.

A rare case of valvular pneumoperitoneum is reported. A 49-year-old Japanese man underwent an emergency laparotomy under a tentative diagnosis of perforating panperitonitis on the 19th post-open heart surgery day. A large volume of free intraperitoneal gas was revealed, but no identification of gastrointestinal perforation. On the 17th postlaparotomy day, pneumoperitoneum recurred. On the 41st postlaparotomy day, a tiny gastric perforation was detected with an oral contrast medium. The patient died of liver failure due to serum hepatitis. The autopsy revealed a minute gastric ulcer scar 2 mm in diameter in the mucosa of the fornix, which was thought to have caused the valvular pneumoperitoneum. A literature review was made of 8 reports on 11 cases. In two cases of valvular pneumoperitoneum, the perforating site could not be found even during laparotomy. It is suggested that either gastrointestinal series or endoscopy must be carefully repeated in order to identify the perforating site.

Humans↗

PubMed1991

New operative method for distal aortopulmonary septal defect.

A new technique is described for repairing distal aortopulmonary septal defect with aortic origin of the right pulmonary artery in a 26-day-old neonate. To prevent the narrowing of the proximal right pulmonary artery in the distal aortopulmonary septal defect caused by conventional intraluminal prosthetic patch reconstruction, rerouting of the right pulmonary artery using native aortic wall tissue without artificial material was performed. This method seems to be superior to the conventional method, especially during the neonatal period.

Anastomosis, Surgical↗

PubMed1991

Cytogenetic analysis of hepatic cell lines derived from SV40-T antigen gene-harboring transgenic mice.

A total of five hepatic cell lines were established from SV40-T transgenic mice at different stages of development. Karyotype analysis performed on these cell lines revealed 1) chromosomal instability manifested by numerous karyotypic alterations, 2) non-random numerical changes of chromosome number 18 and 3) frequent occurrence of marker chromosomes in four of the five lines. These findings indicate that genetic abnormalities occur very frequently in hepatocytes of the transgenic mice, most probably caused by the mutagenic action of T-antigen, raising the possibility that they play essential roles in initiation and progression in this model of murine hepatocarcinogenesis.

Animals↗

PubMed1991

Low frequency of ras activation in 2-acetylaminofluorene- and 3'-methyl-4-(dimethylamino)azobenzene-induced rat hepatocellular carcinomas.

Activation of ras protooncogenes in 11 2-acetylaminofluorene (AAF)-induced hepatocellular carcinomas (HCCs) or liver cell lines and 9 3'-methyl-(dimethylamino)azobenzene (3'-Me-DAB)-induced HCCs in rats was examined using the NIH3T3 cell transfection assay and oligonucleotide hybridization analysis. Only one cell line established from a AAF-treated rat liver demonstrated transforming activity with a point mutation and ATTA transversion at the second position of H-ras codon 61. The rates of ras activation were thus very low for both AAF- and 3'-Me-DAB-induced rat HCCs, the results thus extending and confirming the findings indicating that ras activation in rat HCCs induced by various type of carcinogens is infrequent.

2-Acetylaminofluorene↗

PubMed1991

Normal brain damage after radiotherapy of brain tumours.

A total of 106 patients were examined for adverse effects to the brain from 60Co or proton radiotherapy. Radiation induced change (RIC) developed within the irradiated field 40-60 months after doses of 800-1000 neuNSD or 70 TDF and in 10-20 months after doses of more than 1700 neuNSD or 100 TDF. The incidence of RIC increased significantly with increasing age. Furthermore pathological changes like oedema and infarction in the brain tissue may be an important factor for the development of RIC in the central nervous system (CNS).

Adult↗

PubMed1991

A nationwide survey on transient hyperammonemia in newborn infants in Japan: prognosis of life and neurological outcome.

A nationwide survey of transient hyperammonemia in newborns was carried out in Japan. A total of 18 patients, consisting of 12 male and 6 female infants, were reported from 11 facilities. These neonates exhibited hyperammonemia with plasma ammonia levels in the range from 124 to 6256 micrograms/dl. Four newborn infants of the 18 died in the neonatal period, and an additional one died in the early infancy. Among the 13 infants who were alive at the time of this survey, 6 had neurological sequelae, including mental retardation, spastic quadriplegia and epilepsy. The multivariate analysis revealed that the Apgar score at 1 minute, peak plasma ammonia concentration, birth weight and sex were significant factors affecting the prognosis of life.

Ammonia↗

PubMed1991

Radiotherapy in inoperable stage I lung cancer.

In 38 cases of Stage I lung cancer, for which surgery was not indicated because of poor cardiopulmonary function or other reason, radical irradiation yielded excellent results. The five year survival rate was 42.1%, the 10-year survival rate 28.4% and the 15-year survival rate 17.1%. Postradiation complications which can be life-threatening, were acceptably low in incidence, and there was no radiation-related death. The results support the concept of radical irradiation being acceptable as a treatment modality for Stage I lung cancer if the patients concerned cannot have surgery because of poor cardiopulmonary function or some other reason.

Female↗

PubMed1991

New enzyme immunoassays for specific assay and general detection of Trypanosoma cruzi, epimastigotes.

A highly specific competitive enzyme-linked immunosorbent assay for the epimastigote of Tulahuen strain was developed by using the usual 3 immunological reagents, a rabbit antiserum specific for T. cruzi, epimastigote of Tulahuen strain, beta-D-galactosidase-labeled goat anti-rabbit immunoglobulin G and the solid-phase cell fragments of the epimastigote of Tulahuen strain. A new method, the selected antibody enzyme immunoassay (SAEIA) which generally detected all strains of the epimastigote tested with the same working range, was developed by changing only the solid-phase antigen to the epimastigote of Y strain among the 3 immunological reagents. Both assays permitted us to measure accurately as little as 1,000 parasites per assay tube. Scope of the SAEIA was limited to the epimastigote. Both life-cycle forms of T. cruzi which appear in mammals, amastigote and trypomastigote, and other kinetoplastids showed low cross-reaction values by the assay. The assay principle of the new method and a preliminary study to apply the SAEIA for finding the field T. cruzi-infected insect vectors were also reported.

Animals↗

PubMed1991

In vitro progression-associated c-H-ras activation in neoplastic hepatocyte lines established from SV40-T antigen gene-harboring transgenic mice.

In order to investigate the molecular mechanisms of multistep hepatocarcinogenesis in SV40-T antigen gene-harboring transgenic mice, 9 hepatocellular carcinoma (HCC) lines and 10 "preneoplastic" hepatocyte lines were established from the animals and their biological and molecular changes during culture were investigated. Three of the 9 HCC lines showed progression during culture in terms of growth rate and growth capability in soft agar and in nude mice. This progression was associated with the appearance of activated c-H-ras oncogene. Including these 3 lines, H-ras activation was observed in a total of 7 of the 9 HCC lines (78%), whereas it was found only in 1 of 10 (10%) "preneoplastic" hepatocyte lines. These data thus indicate that H-ras activation may be an event occurring at a relatively late stage of hepatocarcinogenesis in this transgenic mouse system and that it may serve towards completion of the carcinogenic process together with the T-antigen.

Animals↗