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Biomedical subjects

R Sasaki

Publications and source records attributed to R Sasaki.

At least 271 records · Page 15Linked to original sources
PubMed1987

[Family study of cancer among gastrectomized patients].

The purpose of this study was to examine whether patients with gastric cancer differ from those with benign gastroduodenal diseases in terms of familial disposition. This series consisted of 1,233 patients with gastric cancer and 2,200 patients with benign gastroduodenal diseases, who had had a gastrectomy between 1972 and 1979 in one hospital. The family information on cancer deaths of first and second relatives of the patients was obtained at the time of operation. The age-adjusted relative risk of positive family history of cancer was higher among the patients with gastric cancer than that among those with benign gastroduodenal diseases. The patients with diffuse type of cancer had a higher risk of positive family history than those with intestinal type of cancer. The non-cancer patients with family history had a slightly higher risk, although not statistical significant, to die from cancer than those without family history. Higher frequency of blood type A was seen in gastric cancer patients with positive family history. These results suggest that certain types of gastric cancer may seem to be associated with genetic factor.

ABO Blood-Group System↗
PubMed1986

Effect of 5-azacytidine on the differentiation of human leukemia K-562 cells.

The treatment of K-562 cells with 10(-5) M to 10(-7) M 5-azacytidine induced a marked increase in benzidine-positive cells. Similarly, the exposure of K-562 cells to 2 X 10(-3) M butyric acid or 5 X 10(-7) M 1-beta-arabinofuranosylcytosine or 1 X 10(-3) M hydroxyurea induced an erythroid differentiation of K-562 cells. The activity of DNA-methyltransferase and the level of methylcytosine in newly synthesized DNA were significantly decreased when the cells were treated with 5-azacytidine or butyric acid, while 1-beta-arabinofuranosylcytosine or hydroxyurea had no inhibitory effect on DNA-methylation of K-562 cells. These results suggest that the inhibition of DNA-methylation is not necessarily a specific phenomenon for erythroid differentiation of K-562 cells.

Azacitidine↗
PubMed1986

Isolation and characterization of cDNA encoding rabbit reticulocyte 2,3-bisphosphoglycerate synthase.

We have isolated and sequenced a cDNA clone containing the entire coding region of rabbit reticulocyte 2,3-bisphosphoglycerate (DPG) synthase. The cDNA was verified by translation of the hybridization-selected RNA and by demonstrating identity of the deduced amino acid (aa) sequence to the sequences of CNBr peptides of the purified enzyme. The aa sequence of the enzyme was homologous to the reported sequence of the human enzyme [Haggarty et al., EMBO J. 2 (1983) 1213-1220], especially in the N-terminal half (aa 1-142). Northern blot analysis of rabbit reticulocyte poly(A)+ RNA revealed a single species of mRNA with about 1700 nucleotides.

Amino Acid Sequence↗
PubMed1986

Mitogen-induced changes in sialyltransferase activity in human normal and leukemic lymphocytes.

Phytohemagglutinin-P (PHA-P) and concanavalin A (Con A) induced an increase in sialyltransferase (S-T) activity of the blood lymphocytes within 24 hours. PHA-P induced the maximal increase in S-T activity in the lymphocytes at 10 micrograms/ml and with Con A at 5 micrograms/ml. PHA-P induced a greater response than that by Con A. An additional effect of these mitogens was not observed. The exposure of cell extracts to these mitogens did not induce the increase in S-T activity. PHA-P or Con A had no effect on the induction of terminal deoxynucleotidyl transferase (TdT) activity, TdT-positive cells or peanut agglutinin (PNA)-positive cells from blood lymphocytes. Therefore, the change of the lymphocytes induced by these mitogens does not indicate a reversion to more immature state of lymphocyte differentiation, but represents a process of the functional differentiation to more activated lymphocytes. These mitogens had only a slight effect on S-T activity of human T-lymphoid leukemia cell lines. The decreased effects of the mitogens on S-T activity of leukemic cells may reflect the change of the membranes due to malignant transformation or the incomplete membrane structure in undifferentiated leukemic cells.

Cell Line↗
PubMed1986

[Epidemiological aspects of cancer and dietary habits].

Causal association between dietary habits and cancer is supported by both epidemiological and laboratory studies and dietary factor is at present one of the most important risks in carcinogenesis. However, the mechanisms of long low-dose exposure to dietary metabolites in carcinogenesis are little known, and there could be many other factors intervening over a long latent period, even if initiation and promotion of cancer occurred as a result of such dietary factors. The purpose of this paper was to review very preliminary reports on epidemiological studies carried out by Ogata-Segi among Japanese in Japan and by Haenszel among Japanese-Americans in Hawaii, together with those of others in the recent years and to evaluate the role of dietary factors in carcinogenesis. Recent epidemiological studies have repeatedly confirmed such dietary effects on cancers, but short-term intervention trials based on certain nutrients such as vitamins and minerals failed to demonstrate any suppressive effects among human populations. A number of other prospective studies on dietary intervention are in progress, but it appears to be difficult to obtain direct evidence from such studies on the population level, due to a lack of knowledge of the complicated metabolic processes of nutrients and their carcinogenic influence on cells and tissues.

Body Weight↗
PubMed1986

[A case of complete remission from acute myelogenous leukemia in second relapse achieved using an intermediate-dose cytosine arabinoside (ID Ara-C) regimen].

A 57-year-old-male patient with acute myelogenous leukemia in second relapse who was refractory to BHAC . AMP [behenoyl arabinosyl cytosine (BHAC), aclacinomycin, 6-mercaptopurine and prednisolone (PSL)] and BHAC . DVP [BHAC, daunomycin, vincristine and PSL] was treated with an intermediate-dose cytosine arabinoside (ID Ara-C) regimen. This schedule consisted of a 1-h infusion of Ara-C at a dose of 500 mg/m2 every 12 h for 6 d (days 3-8), in combination with doxorubicin 50 mg/m2 on day 1 and vincristine 1 mg/m2 on day 2. The patient achieved a complete remission 23 days after completion of Ara-C and was treated with ID Ara-C (Ara-C days 3-6) as a consolidation. Remission duration was only 2.5 months. Plasma Ara-C concentrations were assayed by HPLC and the peak level was 6.7 micrograms/ml. Side effects were mild nausea, vomiting, alopecia and moderate skin rash.

Cytarabine↗
PubMed1986

[Dietary habits among smokers].

Differences in dietary habits between smokers and non-smokers were examined, using the data of well-designed case-control study of colon cancer. Smokers took much more coffee, beef and sake than non-smokers, and smokers tended to take meals irregularly. These dietary habits showed dose-response relationship in the amount of smoking. Odds ratio of proportion of smokers with the above four factors to those without any factors was 10.5, and those with two or three factors were 2-6. These results suggest that the interaction of smoking and dietary habits should be analysed in epidemiological study on cancer.

Adult↗
PubMed1985

Characterization of extramedullary tumors in a case of Ph-positive chronic myelogenous leukemia: possible involvement of immature T lymphocytes.

A 42-year-old male with chronic myelogenous leukemia (CML) developed acute transformation associated with subcutaneous tumors. Histopathologic examinations of the tumors were done on two occasions; the first study revealed reticulum cell sarcoma-like features, and the second suggested a blastoma. Chromosomal analysis showed that the cells of the tumors originated from the CML clone. The cells had a negative reaction for myeloperoxidase by electron microscopy. Furthermore, biochemical and surface marker studies revealed that the tumor cells contained a significant terminal transferase activity. However, they did not express E- or EAC-rosette receptors, Ia-like antigens, or common ALL antigens.

Adult↗
PubMed1985

Factors influencing ascorbate free radical formation.

Several constituents of serum and related substances were examined in order to find factors influencing ascorbate radical formation. Human ceruloplasmin and albumin catalyzed singly ascorbate oxidation and caused a remarkable increase in ESR intensity of the ascorbate radical. Although, however, the combination of these two factors showed synergic effects on catalysis of ascorbate oxidation, the radical intensity significantly decreased. Fibrinogen and fetuin showed inhibitory effects on catalysis of ascorbate oxidation, whereas transferrin, citric acid, or other related substances exhibited no effect. A new factor which inhibited ascorbate oxidation was found in a serum fraction. These results indicate there is a counterbalanced equilibrium in the redox process of ascorbate in serum and the intensity of ascorbate radical is influenced by the summation of the complicated effects of many factors.

Ascorbic Acid↗