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Biomedical subjects

T Ohsawa

Publications and source records attributed to T Ohsawa.

At least 73 records · Page 4Linked to original sources
PubMed1989

Lack of modifying effects of linolic acid hydroperoxides and their secondary oxidative products on combined 7,12-dimethylbenz[a]anthracene and 1,2-dimethylhydrazine-initiated mammary gland, ear duct and colon carcinogenesis in female Sprague-Dawley rats.

Effects of hydroperoxides, autoxidation products of linolic acid (HPO) and secondary oxidative products of HPO (SOP) (5% each in diet) were examined in female Sprague-Dawley rats. HPO and SOP administration was carried out during or subsequent to two injections of dimethylhydrazine (DMH) (40 mg/kg body wt s.c.), and a single i.g. dose of 7,12-dimethylbenz[a]anthracene (DMBA) (50 mg/kg body wt). No significant differences in the incidences of tumors in the mammary gland, colon, ear duct and hematopoietic system associated with HPO or SOP treatment were evident, during or after carcinogen exposure. The present results therefore indicate that the environmental contaminants, HPO and SOP, lack any potential for modification of mammary gland or colon carcinogenesis under the conditions of the investigation.

1,2-Dimethylhydrazine↗
PubMed1989

[MR imaging of femoral head avascular necrosis with STIR sequence].

The uncomplicated bone necrosis is usually demarcated by reactive interface (RI). To analyze signal characteristics of RI, MR imaging of the hip was done using short TI IR (STIR) as well as short/long TR pulse sequences at 0.22 tesla. On STIR sequence the RI was observed as a high-signal line or ring with the shape identical to that of short TR image. The double line sign was not seen in early stage. The best explanation of high signal intensity of RI on STIR is that it has prolonged T1 and T2 secondary to high water content. It is concluded that STIR is an unique way to demonstrate RI in early osteonecrosis.

Adult↗
PubMed1989

Prometaphase chromosomes in the tricho-rhino-phalangeal syndrome type I.

Prometaphase chromosome analysis was undertaken in a patient with familial tricho-rhino-phalangeal syndrome type I (TRPS-I). The patient had apparently normal chromosomes and produced counterevidence to part of Bühler's hypothesis. Thus, although some cases of typical TRPS-I may be derived from a deletion of 8q24.12, others might be caused by gene mutation or submicroscopic deletion involving the corresponding locus within the band 8q24.11----24.13.

Abnormalities, Multiple↗
PubMed1989

Immunotherapy using Freund's adjuvant and recombinant interleukin-2 combined with transarterial chemoembolization for hepatocellular carcinoma.

A new immunotherapy for hepatocellular carcinoma (HCC) using Freund's adjuvant and recombinant interleukin-2 (IL-2) combined with conventional transarterial chemoembolization therapy was performed. In 16 patients with HCC and one patient with metastatic liver cancer receiving this therapy, decrease and suppression of reelevation of alpha-fetoprotein after therapy was observed. Disappearance of tumor thrombi of HCC in the main portal vein was observed in a patient, and decrease of carcinoembryonic antigen was also observed in a patient with metastatic liver cancer. The present therapy using Freund's adjuvant and IL-2 is likely to open a new avenue for the treatment of patients with advanced liver cancer.

Aclarubicin↗
PubMed1989

Expression of tumor necrosis factor at a specific developmental stage of mouse embryos.

We investigated the expression of the tumor necrosis factor (TNF) gene during development of mouse embryos, and observed its transient expression on Days 9 and 10 of gestation. We also detected a 25-kDa protein showing immunological cross-reactivity with mouse TNF antibody in an extract of 10-day embryos. These results suggest that TNF plays a role in mammalian ontogenesis.

Animals↗
PubMed1989

Changes of mouse brain gangliosides during aging from young adult until senescence.

The brain gangliosides from young adult to senescent mice (BDF1 and C57BL/6) were studied. The total ganglioside concentrations of the whole brains were almost constant from young adulthood until the beginning of senescence, but decreased constant from young adulthood until the beginning of senescence, but decreased during senescence to about 80% of the constant level observed at the period before the beginning of senescence. In spite of the constancy of the ganglioside concentrations at the period before the beginning of senescence, the composition gradually changed, with an increase of GM1 and decreases of GD1b, GT1b and GQ1b. During the senescence, all of the gangliosides decreased in their concentrations, but GD1a, GT1b and GQ1b decreased to a markedly greater extent (GT1b greater than GD1a greater than GQ1b). The regional gangliosides in olfactory bulb, cerebrum cortex, cerebrum white matter, hippocampus, hypothalamus, cerebellum and medulla oblongata were compared between 3- and 30-month-old mice of both strains. Significant changes in ganglioside concentrations were observed in both strains in the cerebrum and the hippocampus. In the cerebrum white matter, cerebellum and medulla oblongata, GM1 and GM4 contents significantly increased in the senescent mice.

Aging↗
PubMed1989

Age and cell density dependent changes of gangliosides in human diploid fibroblasts.

The gangliosides in human diploid fibroblasts--TIG-1, TIG-7, and IMR-90--were analysed at different cell densities at early and late passages to clarify the relationship between age and cell density dependent changes of the gangliosides. In early passages, the ganglioside concentrations increased with increase in cell density. At late passages, however, the concentrations were lower than those at the early passages either in the growing or confluent phase, and slightly increased with increase in cell density. The pattern of ganglioside compositions were apparently different between early and late passage cells either in growing or confluent state. In the early passages, GM3 and GD3 were major constituents, and GM2, GD1a, or the other more complex gangliosides were detected as minor components. With increase in cell density, the content of GM3 decreased, whereas GD3 and the others increased. At the late passages, however, GM3 was the major component, and GD3, GM2, or GD1a were minor, but the others were hardly detectable. The ganglioside pattern did not change with increase in cell density. Thus, the age-dependent changes of gangliosides could be distinguished from the cell density dependent alterations.

Cell Count↗
PubMed1989

Follow-up study of atlanto-axial instability in Down's syndrome without separate odontoid process.

Clinical and roentgenologic studies were performed in 69 children with Down's syndrome, without the separate odontoid process, that could be followed for more than 5 years. At the follow-up examination, the atlanto-odontoid process interval (AOI) in flexion, neutral, and extension of the cervical vertebrae significantly decreased when compared with the one at the initial examination. This was particularly obvious up to 5 years of age. Although 14 of 69 cases (20.3%) had atlanto-axial instability at the initial examination, this decreased to four cases (5.8%) at the follow-up examination. However, there were two cases of atlanto-axial instability who were over 10 years of age. There was no significant difference in the minimum sagittal diameter (MSD) at the atlantal level between each position at both the initial and follow-up examinations. Moreover, there was a tendency for the MSD of the cases of positive instability at the follow-up examination to be smaller than those of the cases of negative instability. The degree of ligament laxity improved with increasing age and there was statistically the negative correlation. Although there was a tendency for the AOI to decrease with improvement of the degree of ligament laxity, the correlation could not be confirmed.

Aging↗
PubMed1989

The secretion of high molecular weight cathepsin B from cultured human liver cancers.

The biochemical characteristics of cathepsin B secreted from cultured human liver cancer cells were examined. The enzyme activity of culture medium against a synthetic substrate, N-carbobenzoxy-L-arginyl-L-arginine-4-methyl-coumaryl-7-amide, was dependent on the addition of cysteine, and the optimal pH was found to be 6.0. No activity was observed when the enzyme source was fresh medium not used for culture. These results suggest that the enzyme released from liver cancer cells is the thiol-protease cathepsin B. The molecular weight of the enzyme with 90% of the total activity was 40,000. Two cathepsin B molecules were found in liver tissue from patients with hepatocellular carcinoma (HCC); one was equivalent in size to the secreted enzyme, and a smaller one was the same as normal liver cathepsin B (27,000), which was also obtained from HCC-bearing cirrhotic liver. These results demonstrate that two molecules of cathepsin B are synthesized in liver cancer, and that the larger one is released into the surrounding tissue.

Cathepsin B↗
PubMed1989

Nephrotoxicity of pyrroloquinoline quinone in rats.

When pyrroloquinoline quinone (PQQ) was intraperitoneally injected into rats daily for 4 days at a dose of 11.5 mg/kg body weight/injection, functional and morphologic changes of the kidneys were clearly observed. The most prominent finding was necrotic and degenerative changes of the proximal tubular epithelium as well as hematuria and an elevation of serum creatinine concentration.

Animals↗
PubMed1988

Effects of ganglioside GM1 on DNA synthesis in isolated nuclei and on the activity of DNA polymerase alpha derived from S-phase HeLa cells.

Ganglioside GM1 inhibited either DNA synthesis in isolated nuclei or the activity of DNA polymerase alpha fractionated from S-phase HeLa cells. The concentrations of GM1 necessary for 50% inhibition were about 5 microM and 10 microM for nuclei and DNA polymerase alpha, respectively. The GM1 inhibition of the enzyme activity was suppressed by the addition of 0.05% Triton X-100. Neither gangliotetraosylceramide (asialo-GM1) nor free N-acetylneuraminic acid inhibited the enzyme activity. These facts suggest that GM1, probably in the form of micelles, could influence the enzyme activity by behaving as a polyanionic macromolecule. The kinetic studies indicate that the GM1 inhibition of the enzyme activity was not competitive with the substrate, deoxythymidine triphosphate, but rather with the template DNA. Binding of GM1 and DNA polymerase alpha was suggested by the cocentrifugation of GM1 and the enzyme fraction after their preincubation. It was also observed that other acidic glycolipids, i.e., brain sulphatide and seminolipid, also inhibited the enzyme activity, whilst neutral galactosylceramide did not. The inhibitory influences of these sulphate esters of glycolipids were, similarly to GM1, suppressed by the addition of 0.05% Triton X-100.

Cell Nucleus↗
PubMed1988

Ultrasonographic characteristics of small hepatocellular carcinoma.

The ultrasonographic characteristics of hepatocellular carcinomas (HCC) were investigated. Four typical features of HCCs, "mosaic internal echo pattern", "halo", "lateral shadow" and "posterior echo enhancement", were not recognized in minute HCCs smaller than 2 cm in diameter. These characteristics developed as the tumors grew. Only hypoechoic space-occupying lesions can be considered as small HCCs. In differentiating small HCCs from hypoechoic non-malignant space-occupying lesions in the cirrhotic liver, the ratios of short to long dimensions of the lesions seemed to be important since the ratios of HCCs were significantly larger than those of non-malignant lesions. The fact that 3 hyperechoic small HCCs could not be diagnosed even by celiac arteriography has suggested to us that ultrasonically guided biopsies should be performed in order to differentiate from small hemangiomas. Serum alpha-fetoprotein (AFP) levels of 1/3 of the patients with HCCs were below 100 ng/ml, indicating that it is impossible to detect small HCCs only by measuring serum AFP.

Carcinoma, Hepatocellular↗
PubMed1987

Exogenous GM1 ganglioside caused G1-arrest of human diploid fibroblasts. Flow cytometric studies.

Exogenous GM1 ganglioside (II3 NeuAc-Gg0se4-Cer) inhibited growth and DNA synthesis of human diploid fibroblasts, TIG-1 cells. We examined the effect of exogenous GM1 on their cell cycle traverse by flow cytometry. When the cells were partially synchronized by serum deprivation, addition of GM1 at the time of refeeding caused about 70% reduction of their reentry into S phase from the level observed in the control culture untreated with the ganglioside. However, the addition of GM1 6 h later caused only about 30% reduction of the reentry from the control level. These results suggest that the exogenous ganglioside blocks the cell cycle traverse in an early G1 period. This is consistent with the fact that GM1-treated cells showed a high level of histone H1(0) similar to that observed in G1-arrested cells in confluent culture.

Cell Cycle↗