Search PubMed⌕ Search

Biomedical subjects

S Hosaka

Publications and source records attributed to S Hosaka.

At least 109 records · Page 6Linked to original sources
PubMed1982

Enhancement by bracken of induction of tumours of the upper alimentary tract by N-propyl-N-nitrosourethan.

The effect of bracken on the induction of tumours of the upper alimentary tract by N-propyl-N-nitrosourethan (PNU) was studied in 7-week-old ACI rats. Group I received a solution of 400 pts/10(6) of PNU in their drinking water for 6 weeks; Groups II and III were given PNU as in Group I, and then from 1 week later were fed on diets containing 5 and 30% bracken, respectively, for 33 weeks; Groups IV and V were fed on diets containing 5 and 30% bracken, respectively, for 33 weeks, from 14 weeks after birth. A control group was given basal diet and water only. The experiment was terminated after 40 weeks. The induction of tumours of the upper alimentary tract by PNU was enhanced by bracken diet; i.e. the incidence of pharyngeal tumours in male rats was significantly higher (P less than 0.025) in Group II (10/13) than in Group I (3/13). The incidence and multiplicity of oesophageal tumours in female rats were also higher in Group III than in Group I (P less than 0.025 for incidence; P less than 0.05 for multiplicity). Histologically, the oesophageal tumours in female rats in Groups II and III were not only papillomas but also squamous-cell carcinomas, whereas those in females of Group I were all papillomas. Furthermore, the incidence of tumours of the forestomach in female rats was also higher (P less than 0.05) in Group II (11/13) than in Group I (4/12).

Adenocarcinoma↗
PubMed1982

Polymer microbeads bound to C3 fragments for detecting and labeling cells with C3 receptors.

Monodisperse microbeads (mbs) of a hydrophilic polymer with diameters of 4 microns and 0.2 micron were prepared. To these mbs, IgM or a sugar was bound covalently, and then the mbs were treated with fresh human or mouse serum. This led to the activation of complement and to the binding of C3 fragments to the mbs. C3 fragments fixed on mbs varied with the type of immobilized substance on the mbs and the incubation time of the mbs with fresh serum. Three kinds of mbs binding C3 fragments were prepared: mbs binding C3b, C3bi and C3d (C3hu-mbs); the ones binding C3bi and C3d (C3mu-mbs); and the ones binding only C3b (C3bhu-mbs). They formed rosettes with cells which had the corresponding receptor. When lymphocytes were incubated with C3hu- or C3bhu-mbs with a diameter of 0.2 micron, cap formation of each receptor was observed under a microscope. Once prepared, C3hu-, C3mu- and C3bhu-mbs were stable for more than 4 months.

Animals↗
PubMed1981

Carcinogenicity examination of quercetin and rutin in ACI rats.

Carcinogenicity of quercetin and rutin were examined in inbred ACI strain rats. Rats were given a diet containing 1% or 5% quercetin or 5% rutin for 540 days, or 10% quercetin and 10% rutin for 850 days. Rats in control groups were fed a normal basal diet. Most tumors found in experimental groups were also found in the corresponding control groups. Furthermore, there was no significant difference between the incidence of tumors in the experimental or control groups (P greater than 0.05). Thus, quercetin and rutin tested were not shown to be carcinogenic to ACI rats.

Animals↗
PubMed1981

Carcinogenic activity of 3-amino-1-methyl-5H-pyrido [4,3-b]indole (Trp-P-2), a pyrolysis product of tryptophan.

The carcinogenic activity of 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), a pyrolysis product of tryptophan, was studied in inbred strain ACI rats. Twenty rats received a diet containing 0.01% Trp-P-2 for 870 days. Nineteen rats survived for more than 400 days after the start of feeding, 1 rat developed a hemangioendothelial sarcoma of the liver, and 6 rats developed neoplastic liver nodules. These liver tumors were found only in female rats that died 666--870 days after the start of feeding. No liver tumors were found in control animals.

Animals↗
PubMed1981

Induction of intestinal tumors in rats by dextran sulfate sodium.

The carcinogenicity of dextran sulfate sodium was studied in inbred ACI rats. In group 1, 10 male rats were fed a 10% dextran sulfate sodium diet; in group 2, 14 male and 12 female rats were fed a 5% dextran sulfate sodium diet; and in the control group, 9 male and 9 female rats were given the basal diet without dextran sulfate sodium. After the start of the feeding regimen, all rats given the 10% dextran sulfate sodium diet died of severe diarrhea and anemia within 14 days and 15 of 23 surviving rats fed a 5% dextran sulfate sodium diet developed intestinal tumors between 134 and 215 days. These tumors were induced in the colon and cecum and consisted of adenomas, adenocarcinomas, and papillomas.

Adenocarcinoma↗
PubMed1981

Tumor induction in germ-free rats fed bracken (Pteridium aquilinum).

This study indicated that there was no significant difference in the incidence of intestinal tumors between germ-free and conventional rats fed a diet containing bracken, suggesting that gut microflora did not play a definite role in bracken tumorigenesis. However, bracken induced exclusively sarcoma but no adenocarcinoma in germ-free rats, whereas it induced predominantly adenocarcinoma in conventional rats.

Animals↗
PubMed1980

Mechanical properties of the soft contact lens of poly(methyl methacrylate-N-vinylpyrrolidone).

The mechanical properties of the hydrogel membrane of poly(methyl methacrylate-N-vinylpyrrolidone) were studied for the purpose of making soft contact lenses for extended wear. The dependence of tensile fracture energy, flexibility, and recovery from deformation on the water content and thickness of the hydrogel membrane was studied. Reducing the thickness of a lens was found to exert a more advantageous effect than increasing its water content on maximizing the tensile fracture energy under the condition of an adequate supply of oxygen to the cornea through the contact lens. As long as its water content is controlled between 63 and 78%, the contact lens made of poly(methyl methacrylate-N-vinylpyrrolidone) has the flexibility on the same order as that of conventional soft contact lenses of poly(2-hydroxyethyl methacrylate). The rate of recovery from deformation increases with water content, and the residual elongation is negligible in the range of water content over about 70%. It is concluded that practical requirements for use of these contact lenses, determined by these three mechanical properties, can be satisfied at the same time if the water content of the contact lens is adjusted at about 70%.

Contact Lenses, Hydrophilic↗
PubMed1980

Characterization of mutagenic principles and carcinogenicity of dill weed and seeds.

Among the various kinds of spices tested, the aqueous extracts of dill weed from Anethum graveolens L. and dill seeds from A. sowa D.C. (Umbelliferae), exhibited a mutagenicity to Salmonella typhimurium, strains TA98 and TA100. The aqueous methanol extracts were fractionated by the mutation assay using the strain TA98 with S-9 Mix. Isorhamnetin 3-sulfate (persicarin) and quercetin 3-sulfate were characterized as the mutagenic principles. Carcinogenicity was not observed for dill weed and seeds when the diets containing these in 33% were administered for 450 and 410 days, respectively, to the inbred strain ACI rats.

Animals↗
PubMed1980

Effect of leupeptin, a protease inhibitor, on the development of spontaneous tumors in strain A mice.

The effect of leupeptin, a protease inhibitor, on the development of spontaneous tumors was studied in strain A mice. Three-week-old mice were divided into two groups: one group was fed on diet containing 0.1% leupeptin and the other was fed on basal diet. The experiment was terminated 480 days after the start of a administration of the leupeptin diet. Almost all animals survived until the end of the experiment. In the group given the leupeptin diet, 15 of 50 mice developed liver tumors (14 of 25 males and 1 of 25 females). In the control group, only male mice developed liver tumors (4 of 23 males). There was a significant difference between the incidences of liver tumors in males fed leupeptin diet and basal diet, but there was not in the case of females.

Animals↗
PubMed1980

Effects of cytochalasin B and colchicine on the motility and growth of Yoshida sarcoma cells in vitro.

The effects of cytochalasin B (CB) and colchicine on the motility and growth of cultured Yoshida sarcoma cells are studied by cinematographic methods. CB was found to reduce the average locomotory rate of motile Yoshida sarcoma cells and to enhance the frequency of non-motile cells. On the other hand, colchicine enhanced only the frequency of non-motile cells and did not affect the locomotory rate of motile cells. CB inhibited the growth of Yoshida sarcoma cells at the concentration range of 0.6 to 5 microgram/ml.

Animals↗
PubMed1979

[Critical study on dead cases in recurrent early stomach cancer (author's transl)].

35 deaths of 299 operated early stomach cancers have been studied retrospectively. These cases can be grouped in the following categories: 2 deaths directly due to operation, 7 due to recurrence of carcinoma, 19 due to other diseases including cancer in other sites and 7 cases in which the real causes of death could not be elucidated. Special attention was paid on the 7 recurrent cases: In 4 of 7 patients the histological study revealed lymph and blood vessels invasion in their resected stomachs, lymphnodes metastases in 5 patients and positive cut-end in 2 patients. 5 of 7 patients died within 3 years after operation.

Adult↗
PubMed1979

Induction of hepatic tumors in rats by senkirkine and symphytine.

The carcinogenicity of the pyrrolizidine alkaloids senkirkine and symphytine was studied in male inbred ACI rats. Animals were divided into 3 groups: Group I received ip injections of freshly prepared senkirkine at a dose of 10% of the median lethal dose (LD50) twice weekly for 4 weeks and then once a week for 52 weeks. Group II received ip injections of symphytine at a dose of 10% of the LD50 by the same injection schedule as in group I. The control group was given ip injections of a 0.9% NaCl solution following the same injection schedule as in experimental groups. All group I rats survived for more than 290 days after the start of injections, and 9 of 20 rats developed liver cell adenoma. All group II animals survived for more than 330 days after the start of injections. Of 20 rats, 4 had liver tumors, 3 had hemangioendothelial sarcomas, and 1 had liver cell adenoma. The hemangioendothelial sarcomas showed metastasis in the lungs of 2 rats. The control group had no liver tumors.

Animals↗