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Biomedical subjects

H Saeki

Publications and source records attributed to H Saeki.

At least 181 records · Page 10Linked to original sources
PubMed1984

[Histological classification and prognosis of mammary cancer-histological classification devised by the Japan Mammary Cancer Society and WHO classification].

Between 1966 and 1977, 427 patients with mammary cancer underwent surgery at the Shikoku Cancer Center Hospital. Using these subjects, the histological classification devised by the Japan Mammary Cancer Society was compared with the WHO classification. Since the WHO classification places 80.4% of all cases into the category of invasive duct carcinoma, the significance of the histological classification as a factor in predicting prognosis is reduced. Thus, some other subclassification is needed for practical application. We classified invasive duct carcinoma according to cellular atypism (CAT), structural atypism (SAT) and infiltration mode (INF), and examined their relationship to the 5-year survival rate; there was a positive correlation.

Breast Neoplasms↗
PubMed1983

Stimulation of tyrosinase activity of cultured melanoma cells by lysosomotropic agents.

The tyrosinase (EC 1.14.18.1) activity of cell-free extracts (TyH) of B16 melanoma cells cultured in the presence of 5 to 10 mM ammonium chloride was considerably higher than that of cells from control cultures. This increase in TyH in the presence of ammonium chloride seemed to be due to de novo synthesis of the enzyme, because it was inhibited by 1 microgram/ml of cycloheximide. In the presence of the latter, however, ammonium chloride did increase the tyrosinase activity of living cells in culture (TyC) resulting in about threefold increase in the TyC/TyH ratio, a measure of the extent of tyrosinase reaction exerted by the enzyme present in living cells. This higher TyC/TyH ratio induced by ammonium chloride was also observed in the absence of cycloheximide. Similar increases in TyH, TyC, and TyC/TyH occurred in the presence of methylamine or ethylamine instead of ammonium chloride, but not in the presence of tetraethylammonium chloride, and also in culture medium of higher pH. The apparently similar effects of lysosomotropic bases and medium of higher pH on the TyC/TyH ratio suggest that there are some mechanisms that control the intramelanosomal pH lower than the cytoplasmic pH.

Ammonium Chloride↗
PubMed1983

Presence of 3-amino-beta-carbolines (3-amino-9H-pyrido[3,4-b]indoles), effectors in the induction of sister-chromatid exchanges, in protein pyrolysates.

3-Amino-9H-pyrido[3,4-b]indole (3-aminonorharman) and 3-amino-1-methyl-9H-pyrido[3,4-b]indole (3-aminoharman), effectors for induction of sister-chromatid exchanges in human lymphoblastoid cells, were identified in pyrolysates of casein by high-performance liquid chromatography and UV spectrophotometry, together with some other mutagenic/carcinogenic carbolines. In pyrolysates from a preparation of zein, which contained little tryptophan, only norharman and harman were found in small amounts.

Animals↗
PubMed1983

Directional difference of urethral pressure profile in anterior, posterior and lateral components of canine urethra.

The urethral pressure profile (UPP) was recorded in anterior, posterior, and right and left lateral portions of the canine urethra using a newly designed catheter with only one eye around the circumference of the tip for UPP recording. Our single-eye catheter made it possible to measure UPP in the four aspects separately and confirmed that there was a directional difference in UPP.

Animals↗
PubMed1980

Synthesis and degradation of tyrosinase in cultured melanoma cells.

The tyrosinase (EC 1.14.18.1) activity of cultured B-16 mouse melanoma cells (C2M) in the stationary phase depends greatly on whether the culture medium contains glucose or galactose. The activity in medium containing galactose was about ten times that in medium containing glucose at pH 7.2. This difference in tyrosinase activity was concluded to be due to a shift of balance between synthesis and degradation of the enzyme. Experiments were conducted with stationary phase cultures in the presence of cycloheximide. The melanoma cells did not synthesize tyrosinase in medium containing glucose in the stationary phase. But when they were cultured under identical conditions, except that glucose was replaced by galactose, they continued to synthesize tyrosinase. The rate of synthesis in medium containing galactose at pH 6.3 was one third of that in the same medium at about pH 7, in which the increase in specific activity of tyrosinase per day was about 30 nmoles/mg cell protein per hr. The rate of degradation of the enzyme was practically the same in medium containing glucose as in medium containing galactose, and largely depended on the pH of the culture medium. At pH 6.3, the half-life was about one third of that at pH 7.2, where it was about 1.8 days. The degradation at acidic pH values was much reduced by ammonium salt and was strongly inhibited by the protease inhibitor, leupeptin.

Ammonium Chloride↗
PubMed1979

1-N-Alkyl analogs of butirosin.

Butirosin (Ia), 5''-amino-5''-deoxy-(Ic), 3',4'-dideoxy-(Ie), and 5''-amino-3',4',5''-trideoxy-butirosin A (If) were converted into the corresponding 1'''-deoxo derivatives, Ib, Id, Ig, and Ih by borane reduction. In addition, xylostasin (IIIa) was converted into its 1-N-ethyl derivative (IIIb) by reductive ethylation. Their antibacterial activities were discussed.

Anti-Bacterial Agents↗
PubMed1978

Effects of pH and type of sugar in the medium on tyrosinase activity in cultured melanoma cells.

The tyrosinase (EC 1.14.18.1) activity of cultured mouse melanoma cells B16 in the stationary phase of growth, depends greatly on the pH of the medium and the kind of sugar present. The enzyme activity of a homogenate of cells grown at pH 7.2 in Eagles's MEM supplemented with 10% new born calf serum and con taining galactose in place of glucose, was about ten times that of a homogenate of cells cultured at pH 6.3 in the same medium. The tyrosinase activity changed reversibly on changing the pH of the culture medium. When cultured at a constant pH of 7.2, cells grown with 1 mM galactose had about five times higher tyrosinase activity than cells grown with 1 mM glucose. Only a small amount of lactate accumulated in cultures with glucose and it had little effect on the enzyme activity. These two findings explain the very low tyrosinase activity of cells cultured in medium with 5 mM glucose: the low activity is due to the presence of glucose and to the low pH resulting from conversion of glucose to lactic acid.

Catechol Oxidase↗
PubMed1977

Effects of sugars on melanogenesis in cultured melanoma cells.

A permanent cell line C2M of mouse melanoma B16 was highly melanized in a modified Eagle's MEM supplemented with 10% calf serum, when the medium contained 1 mM galactose and 10 mM pyruvate instead of 5.5 mM glucose. The activity of the key anzyme for melanogenesis, tyrosinase (EC 1.14.18.1), of living cells cultured in the galactose-pyruvate medium was consistently 27 times higher than that of cells in normal MEM. This high level of tyrosinase activity was maintained in the stationary phase, in contrast to the activity of cells in normal medium, which decreased sharply in the stationary phase. It seems likely that tyrosinase activity is suppressed by the presence of glucose rather than stimulated by galactose. This modified medium should be useful obtaining a high level of tyrosinase activity in living cells in culture and in cell-free extracts.

Animals↗