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Biomedical subjects

H Asakawa

Publications and source records attributed to H Asakawa.

At least 73 records · Page 4Linked to original sources
PubMed1990

Interferon-gamma reduces actin filaments and inhibits thyroid-stimulating hormone-induced formation of microvilli and pseudopods in mouse monolayer thyrocytes.

To study the role of interferon-gamma (IFN gamma), which is released from activated lymphocytes in the development of lymphocytic thyroiditis, we investigated the effects of IFN gamma on the morphology of mouse thyrocytes, using scanning electron microscopy. Thyrocytes were cultured in monolayers for 5-7 days and incubated with TSH (10 mU/ml) for 1 h before fixation. IFN gamma (200 U/ml) was added to the culture medium for 1 h to 5 days before TSH stimulation. Coculture of thyrocytes with IFN gamma for more than 24 h inhibited TSH-induced morphological changes in the thyrocytes; IFN gamma inhibited the increase in the number of and elongation of microvilli and the appearance of pseudopods. IFN gamma also reduced the number of actin filaments in thyrocytes, as confirmed by immunofluorescence photometry. These results suggest that IFN gamma inhibits the morphological response of thyrocytes to TSH stimulation by the reduction of actin filaments.

Actins↗
PubMed1990

[Assessment of cisplatin in concurrent use with radiotherapy in esophageal carcinoma--joint research among nationwide multi-facilities, primary results. Research Committee for Radiation and Cisplatin Treatment of Esophageal Carcinoma].

The effect of cisplatin in concurrent use with radiotherapy for esophageal carcinoma has been assessed as a theme of joint research among nationwide 40 facilities for 18 months from October, 1985, to March, 1987. As the subjects, non-operative cases, recurrent cases and metastatic cases diagnosed as esophageal carcinoma were enrolled. Regimens in 4 kinds were used for treatment and CDDP was used concurrently with radiotherapy in all the regimens. The results of classifying and totalizing the effects in 73 cases, of whom the local effects were analyzed, turned out to be: CR-25 cases, CR rate being 34.2% and PR-33 cases, the effective rate being 79.5%. As a result of aggregating the effects by major axis of X-ray image, CR and effective rates were found as 60 and 90% in the cases with the axes less than 5 cm; 36 and 79% in the cases with axes more than 5 cm and less than 10 cm; and 19 and 76% in the cases with the axes more than 10 cm, all respectively.

Aged↗
PubMed1989

Retarding liver cancer growth in the rat by transient repeated hepatic dearterialization.

The effect of repeated ischemic episodes to experimental liver tumors is studied in a group of inbred Wistar-Furth rats. A vascular occluder model was developed specially for the purpose of delivering intermittent compressions to the hepatic artery in the rat. With five daily 1-hr occlusions of the hepatic artery, rats benefited from significantly reduced tumor growth rates compared with controls that underwent sham operation (P less than 0.05). In contrast to results from previous pig experiments, it is demonstrated by angiographic studies that repeated transient dearterialization does not entirely overcome the problem of collateral vessel formation in the rat. Tumor neovascularization continues irrespective of whether the tumor is being dearterialized. It is also observed that in both normal and tumor rats, collateral channels from the left gastric artery temporarily open up when the hepatic artery is obstructed but disappear on reestablishment of flow. As such types of collateral flow are beyond our control, it is imperative that future developments in vascular occlusion therapy should aim at shortening ischemia time and combining with chemotherapy.

Adenocarcinoma↗
PubMed1989

Effect of subculturing on expression of a cell-surface protein antigen by Streptococcus mutans.

Two freshly isolated strains, Xc and Yc, of Streptococcus mutans serotype c from human dental plaque were subcultured 100 times in Brain Heart Infusion broth. The cell-surface hydrophobicity of strain Xc markedly decreased after subculturing 60 times, but that of strain Yc remained unaltered. Radioimmunoassay showed a close correlation between surface hydrophobicity and the amount of a cell-surface protein antigen (PAc) of Mr 190,000. One hydrophilic variant (strain Xc100L), one relatively hydrophobic variant (strain Xc100H), and two hydrophobic variants (strains Yc100H1 and Yc100H2) were isolated from the 100-fold subcultures of hydrophobic strains Xc and Yc, respectively. SDS-PAGE showed that the amount of cell-associated and cell-free PAc of strain Xc100L was smaller than that of strains Xc and Xc100H. Strain Yc100H2 produced larger amounts of cell-associated PAc than strains Yc and Yc100H1. Resting cells of hydrophilic strain Xc100L attached in smaller numbers to saliva-coated hydroxyapatite than did other hydrophobic strains. RNA dot-blot analysis demonstrated a significant decrease in PAc-specific mRNA in strain Xc100L, as compared with strains Xc and Xc100H. Neither rearrangement nor deletion in the structural gene (pac) for PAc of these strains was observed by Southern blot analysis. These findings suggest that a mechanism which regulates the transcription of the pac gene participates in the quantitative variation of PAc after repeated subculturing.

Antigens, Bacterial↗
PubMed1989

Acute ischemic liver failure in the rat: a reproducible model not requiring portal decompression.

We report a model of acute ischemic liver failure which does not require temporary or permanent portal decompression. The model is induced by segmental ischemia of the median and left lateral lobes for 100 min by a vascular clamp applied on the afferent vessels. Declamping is followed by resection of the nonischemic right lateral and caudate lobes. No portal stasis occurs as blood flow to the right lateral and caudate lobes is maintained during the period of clamping. The 24-hour mortality is 76.5%. Evidence of severe liver damage is shown by histological and biochemical studies.

Acute Disease↗
PubMed1989

[A clinical study of the radiosensitization of aclarubicin].

Sixty six patients with an advanced or a relapsed cancer have been treated with a combination of radiation and aclarubicin (ACR). The average irradiation dose was 45 +/- 15 Gy, and the combined total dose of ACR ranged from 130 to 260 mg, depending upon the following differing schedules: 10 mg x 3 or 5/w, 20 mg x 2 or 3/w and 20 mg x 2/d x 2/w. The tumor response attained was 70%, including 30% who achieved a complete response. A high response rate also was observed in rather radioresistant cancerous tumor, such as those of the lung, stomach and esophagus. The adverse effects, such as anorexia, nausea, and so on, were found increase with an increase in the dose of ACR. It thus was concluded that for clinical usefulness, 10 mg of ACR should administered every other day in combination with a definite program of radiotherapy.

Aclarubicin↗
PubMed1988

Preparation of colloidal gold for staining proteins electrotransferred onto nitrocellulose membranes.

This paper describes a simple method of preparing colloidal gold for staining protein blots. Colloidal gold was prepared from 0.005 or 0.01% HAuCl4 by the addition of formalin as a reductant and potassium hydroxide. Staining of small cell carcinoma tissue extract blotted onto nitrocellulose membranes with this colloidal gold solution resulted in the appearance of a large number of clear wine-red bands. The sensitivity of gold staining was 60 times higher than that of Coomassie brilliant blue staining and almost comparable to that of silver staining of proteins in polyacrylamide gel. The sensitivity of this method was also satisfactory in comparison with that of enzyme immunoblotting. The colloidal gold prepared by this method is usable for routine work.

Blotting, Western↗
PubMed1988

Induction of insulitis by adoptive transfer with L3T4+Lyt2- T-lymphocytes in T-lymphocyte-depleted NOD mice.

To clarify the pathogenesis of insulitis in the nonobese diabetic (NOD) mouse, an animal model for human insulin-dependent diabetes mellitus, T-lymphocyte-depleted NOD mice (B mice) were adoptively transferred with spleen and lymph node cells from cyclophosphamide-treated NOD mice after separating the cells with monoclonal antibodies against various T-lymphocyte surface antigens plus complement. Light-microscopic and immunohistochemical studies were also performed to investigate the lymphocytic infiltrations. The incidence of insulitis detected in B mice was much lower when compared with that of the lesion naturally occurring in the NOD mouse. However, higher incidence of insulitis was inducible in B mice by transferring unfractionated lymphoid cells from NOD mice. When the Thy1+ cell-depleted fraction was transferred into the B mice, no increase in the incidence of insulitis was observed. The Lyt1+ or L3T4+ cell-eliminated fraction was also unable to transfer insulitis. Conversely, donor cells depleted of Lyt2+ components successfully induced insulitis in the recipient B mice. These data were consistent with the immunohistochemical study, which showed that the main phenotype of the cells infiltrating the islets was L3T4+. These results suggest the importance of L3T4+Lyt2- T-lymphocytes in the pathogenesis of insulitis in NOD mice.

Animals↗
PubMed1987

Control of traumatic liver hemorrhage in the cirrhotic rat by intraportal infusion of norepinephrine.

The effect of intraportal infusion of norepinephrine (NE) on primary hemostasis in the cirrhotic rat was investigated at standardized liver trauma. Cirrhosis was induced by simultaneous administration of increasing amounts of carbontetrachloride (CCl4) and phenobarbitone. Infusion of norepinephrine took place after cannulation of the gastroduodenal vein. Intraportal infusion of NE resulted in a significant increase in arterial blood pressure and portal pressure in all animals. No difference was observed between cirrhotic and control rats. Cirrhotic animals bled longer and more profusely as compared with the controls. Infusion of NE resulted in significant decrease in bleeding time and blood loss. NE did not affect hematocrit, hemoglobin, platelet, or white cell count. Platelet aggregation was not influenced by the compound. In conclusion, intraportal infusion of NE proved effective in decreasing hemorrhage at liver trauma in cirrhotic rats.

Animals↗
PubMed1987

Serological relationships between serotype-III Streptococcus sanguis and Lancefield group-H streptococci.

Certain strains of Streptococcus sanguis and group-H streptococci have been shown to have similar physiological properties and serological specificities. Serological studies revealed that serotype-III S. sanguis shared a common antigen with the so-called "British" group-H streptococci, but not with the "American" group-H streptococci. Serotype-III antigen was extracted in cold 5% trichloroacetic acid from isolated cell walls of S. sanguis ATCC 10558, and purified chromatographically. The purified serotype-III antigen consisted of neutral and amino sugars and some phosphorus, and was negatively charged. Hapten inhibition of the quantitative precipitin reaction between serotype-III antigen and antiserum indicated the strong possibility of alpha-glucosidic linkages being an immunodeterminant of the antigen.

Antigens, Bacterial↗
PubMed1987

Ultrastructure of extracellular polysaccharides produced by serotype c Streptococcus mutans.

The ultrastructure of extracellular polysaccharides produced in colonies by two clinical isolates and that of a nitrosoguanidine-induced mutant of serotype c Streptococcus mutans with different polysaccharide-synthesizing abilities were compared electron-microscopically. A large amount of polysaccharide was produced from sucrose by colonies of typical serotype c strain MT8148R and a clinical variant MT6801R with an enhanced fructan-synthesizing ability. Transmission electron-microscopy (TEM) revealed that the polysaccharides consisted of three structural components, i.e., globular, single-stranded filamentous, and double-stranded fibrillar structures. These structures were ascribed to production of fructan, water-soluble glucan, and water-insoluble glucan, respectively. On the other hand, two kinds of structures, a globular body and an amorphous substance, were observed by scanning electron-microscopy (SEM). The former was composed of fructan, while the latter contained a mixture of water-soluble and water-insoluble glucans which formed filamentous and double-stranded fibrillar structures under TEM. Very small quantities of polysaccharides were formed in colonies of mutant NG7183, which was derived from S. mutans MT6801R. This strain was found to possess low glucan- and no fructan-synthesizing abilities. The polysaccharides produced in colonies of mutant NG7183 were composed only of filamentous and double-stranded fibrils under TEM. A small amount of amorphous substance was observed by SEM in colonies of NG7183.

Dextranase↗
PubMed1987

beta-Hexosaminidase in plasma and liver after partial hepatectomy in normal and cirrhotic rats.

The liver and plasma level of the lysosomal enzyme beta-hexosaminidase was analyzed in partially (about 70%) hepatectomized rats with normal liver or carbon tetrachloride (CCl4)-induced cirrhosis. The enzyme level of the liver did not show marked changes after partial hepatectomy in either normal or cirrhotic rats. In contrast, the plasma basal level was significantly higher in cirrhotic rats and increased to a peak at 6 h, followed by a decrease to a minimum level 24 h after operation. The enzyme returned to its high plasma basal level at 36 h after partial hepatectomy, when the liver had recovered to 70% of its initial weight. In rats with normal liver the plasma beta-hexosaminidase showed another pattern, with a rapid increase at 6 h and thereafter gradually reaching a peak at 36 h after hepatectomy. We conclude that the cells responsible for increased plasma beta-hexosaminidase in cirrhotic rats are situated in the liver.

Alanine Transaminase↗
PubMed1987

[Analysis of 5-year survivors of esophageal cancer treated with radiation and chemotherapy].

From 1967 to 1980, 240 cases of esophageal cancer, consisting of 153 curative and 87 palliative cases, were treated with a combination of radiation and chemotherapy. The five-year survival rate in 124 curative cases given a dose of more than 50 Gy was 12.9%, and 17 cases survived more than 5 years. In the 5-year survivors, T1 in the advancement of tumors, less than 7 cm in length, and cancer of both the serrated and tumorous types were characteristic factors, indicating a good prognosis. These cases were irradiated with a dose of 60-70 Gy and the tumors showed a high response to irradiation.

Aged↗
PubMed1987

[Prognosis of 5-year survivors of esophageal cancer treated with radiation and chemotherapy].

Seventeen 5-year survivors, treated with a combination of radiation and chemotherapy, were followed up from 5 to 10 years. Out of them, 10 cases died within 10 years after the completion of radiotherapy. Late local recurrence and remote metastasis of esophageal cancer were observed in 3 cases, and other malignancies of the stomach, lung and esophagus were found in 3 other cases. Furthermore, the cause of death was late radiation injuries (radiation myelopathy and pulmonary fibrosis) in 2 cases and intercurrent disease in 2 others. Dysphagia due to cicatricial structure of the esophagus occurred in 5 cases.

Aged↗