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Biomedical subjects

H Asakawa

Publications and source records attributed to H Asakawa.

At least 91 records · Page 5Linked to original sources
PubMed1986

Sucrose-dependent cell adherence and cariogenicity of serotype c Streptococcus mutans.

Four strains of serotype c Streptococcus mutans differing in glucosyltransferase (GTase) and fructosyltransferase (FTase) activities were examined. These strains had been made resistant to streptomycin. FTase activity of an S. mutans clinical variant, MT6801R, which forms large mucoid colonies on sucrose-containing agar, was considerably higher than that of a typical serotype c strain, MT8148R, which forms small, rough colonies on the same agar. Two mutants, NG14 and NG7183, were induced from strain MT6801R by N-methyl-N'-nitro-N-nitrosoguanidine, and were found to be streptomycin-resistant. GTase and FTase activities of mutant NG14 were similar to those of the typical serotype c strain, while in mutant NG7183 the two enzyme activities were very low. Growing cells of these strains (except NG7183) adhered firmly to a glass surface in sucrose broth. Resting cells of all strains attached in small numbers to saliva-coated hydroxyapatite in the absence of sucrose. On the other hand, the presence of sucrose markedly enhanced the attachment of cells of strains MT8148R, MT6801R and NG14, but not NG7183. Cell-surface hydrophobicity and acid production of all strains were similar. Both strain MT8148R and NG14 colonized tooth surfaces and produced significant dental caries in specific-pathogen-free rats. Strain MT6801R had lower colonization ability and cariogenicity when compared with strains MT8148R and NG14. Furthermore, mutant NG7183 was able to colonize the tooth surfaces in small numbers, but failed to cause dental caries. These results indicate that sucrose-dependent cell adherence mediated by de novo glucan synthesis is necessary for the accumulation of serotype c S. mutans cells on the tooth surface and the induction of dental caries.

Adsorption↗
PubMed1985

Flow- and pressure-adapted portal arterialization in dogs.

The effects of portal arterialization after portacaval shunt were studied in dogs. Flow- and pressure-adapted portal arterialization was performed by mounting a Teflon cuff on an autogenous vein bypass graft between the hepatic stump of the portal vein and the right renal artery. Immediately following operation, the total hepatic blood flow and intrahepatic portal venous pressure were within normal range. Eight weeks after operation, the intrahepatic portal venous pressure remained within the preoperative range, while total hepatic blood flow had increased double or triple. However, structural change due to increased flow was absent in the liver, even sixteen months after operation. Body weight, liver enzyme chemistry, ICG clearance rate, and amino acid metabolism were well maintained for the entire period of investigation. These findings suggest that sequelae such as hepatic encephalopathy and impaired hepatic metabolism after portacaval shunt can be avoided by portal arterialization, in the presence of an appropriate flow and pressure.

Alanine Transaminase↗
PubMed1985

Isoferritins from tumorous and non-tumorous human liver.

Human ferritins purified from normal liver (LF) and from hepatocellular carcinoma (HF) showed different biochemical and immunological characteristics. Subunit preparations from the isoferritins showed differences in isoelectric focusing patterns, although both HF and LF were found to be composed of H and L subunits with apparently the same molecular weights. It is postulated that heterogeneities between the two isoferritins are not merely due to different proportions of H and L subunits, but also result from the existence of distinct species of the subunits bearing different surface electric charges.

Carcinoma, Hepatocellular↗
PubMed1985

[Evaluation of combined radiotherapy of gastric carcinoma].

Combined radiotherapy with chemotherapy was performed on 82 patients with advanced gastric carcinoma (T2-T4: M0). A small target volume, including the primary lesion and regional lymph nodes (N1), was irradiated with the dose of 60 Gy. The survival rate was 21% at two years and 6% at five. The prognosis was better in cases of less advanced carcinoma, types I and II carcinoma and radioresponsive tumor. As the conclusion, it was suggested that this combination therapy could be curative in a few patients and be valuable to prolong the life of some others.

Adenocarcinoma↗
PubMed1984

Clinical isolates of Streptococcus mutans serotype c with altered colony morphology due to fructan synthesis.

Streptococcus mutans MT6801 , MT6861 , and MT6879 , which form large mucoid colonies on mitis salivarius agar, were isolated from a mother and her two daughters. These isolates were identified as serotype c by immunodiffusion with serotype-specific antisera. The large colonies formed on sucrose-containing agar were found to contain water-soluble fructan . The cell-free fructosyltransferase ( FTase ) activity of the strains which formed large colonies was five to eight times higher than that of serotype c S. mutans which produced small, rough colonies typical of this serotype. Furthermore, greater quantities of fructan were synthesized from sucrose by growing cells of MT6801 when compared with MT8148 , a typical serotype c S. mutans. Glucosyltransferase and FTase could be isolated by chromatofocusing from culture supernatants of MT6801 and MT8148 . The FTase activity of both strains was eluted at pH 4.5, and glucosyltransferase was released by elution with an NaCl linear gradient. The eluted FTase activity of MT6801 was significantly higher than that of MT8148 . Strains MT6861 and MT6879 were also found to possess a similar property in terms of FTase activity. These results suggest that formation of large mucoid colonies by these strains is a consequence of high FTase activity.

Adult↗
PubMed1984

Radiation therapy of carcinoma in the rectum and sigmoid colon.

Radiation therapy combined with some anti-cancer drugs was performed in a total of 79 patients with carcinoma of the rectum and sigmoid colon, consisting of 41 primary, 25 recurrent and 13 postoperatively irradiated ones. Relief of subjective symptoms was observed in 50% or more of primary and recurrent patients. Radiation response of tumor was marked in 23 (56%) of primary ones. Five-year survival rate was 21% in the primary patients without any remote metastasis, 11% in the recurrent and 27% in the postoperatively irradiated. It was concluded that this combination therapy might be valuable for getting a cure in the primary patients with radioresponsive tumor (T1-T4: M0) and the patients with localized residual lesion, and for good palliation in the patients with far advanced and recurrent carcinoma.

Adenocarcinoma↗
PubMed1984

[Combined treatment of esophageal cancer with radiation and bleomycin. Part VI. Long-term results and 3-year survivors].

Combined treatment of esophageal cancer with radiation and bleomycin was given to 136 patients receiving curative treatment, in whom distant metastasis was not noticed before the start of this treatment and more than 50 Gy was irradiated. Actuarial survival rates of the patients were 62% at one-year, 33% at two-year, 23% at three-year and 14% at five-year. The local recurrence was noted in 53% and the remote metastasis was observed in 27% of them. These survival rates and three-year survivors were analyzed and discussed. They were closely related to advancement, radiological type and radiation response of tumor. It is concluded that this combined radiotherapy is useful to improve one to three-year survival rate but is not sufficient to increase the permanent cure rate. Curable indications for this therapy are T1-2, N0-1, M0 cases with the radioresponsive type of tumor.

Adult↗
PubMed1984

[Results of combined therapy of irradiation and bleomycin suppository for advanced uterine cervical cancer].

Efficacy, survival rats and adverse effects of the combined therapy of irradiation with intravaginal bleomycin suppositories were analyzed and discussed in 49 patients with uterine cervical cancer. The results were as follows: Histological examination of biopsy specimens from the uterine cervix taken just after the completion of this treatment showed favorable control over the primary lesions. However, the efficacy of the bleomycin suppositories was too mild to form a basis for treatment without intracavitary irradiation. Because of the low concentration of bleomycin in serum after suppository administration, it is thought that bleomycin would have little effect on distant metastases. Survival rates in stage III patients were 83% at 12 months, 77% at 24 months and 70% at 36 months. These were superior to those for irradiation alone. The major adverse effect of bleomycin suppositories was fever, reduction of the bleomycin dose in each suppository but controlled this to some extent Lung fibrosis or severe damage to the liver, kidney and bone marrow were not found.

Adult↗
PubMed1984

[Radiotherapy for esophageal carcinoma with broncho-esophageal fistula].

We studied treatment methods after fistula formation in 14 esophageal carcinoma patients with broncho-esophageal fistulae. Among 12 patients, 8 had no treatment, one was operated and 3 underwent radiotherapy using conventional fractionation. In only one case was there temporary closure of the fistula; none of the patients survived for more than 1 year. The other 2 patients were treated by the long protracted method (1.5 Gy/day). Long-term closure of the fistula was seen. These patients received additional low-dose rate teletherapy (1 Gy/hour, 7 Gy/day) and both survived for over 1 year.

Aged↗
PubMed1984

[Treatment of operable breast cancer by tumorectomy and irradiation].

Six patients with operable breast cancer were treated by tumorectomy followed by radiotherapy at Miyagi Seijinbyo Center between 1972 and 1982. All patients are alive but local recurrence at the irradiated breast and lung metastasis occurred in one patient each. Acute skin reaction was evident in two patients and slight fibrosis of the irradiated breast was observed in another patient. However, we encountered no severe complications in any of our patients. Cosmetic results were satisfactory with the exception of one patient who underwent mastectomy after local recurrence of the carcinoma.

Adenocarcinoma↗
PubMed1984

[Clinical evaluation of hypoxic cell sensitizer (Misonidazole)].

Clinical effectiveness and toxicity of Misonidazole were analyzed and discussed in 22 cases of carcinoma of uterine cervix, 17 cases of esophageal cancer and 11 with other malignancies treated by radiation. By clinical and histologic examination in the controlled trial, it was shown that radiation response of tumor was slightly sensitized in the treated group with this drug, compared with that in the control group. It was confirmed that there was no significant difference between radiation response of tumor in both groups. Peripheral neuropathy was a complication in 10% and toxicodermatitis in 12% even if the total dose administered was below 10 g/m2. From these results, it was strongly suggested that this drug is not suitable in combination with simple fractionated irradiation as a hypoxic cell sensitizer.

Aged↗
PubMed1983

Possibly unique subunit(s) of human ferritins responsible for tissue specificity.

The biochemical characteristics of human placental and hepatic ferritins were compared. By DEAE cellulose column chromatography, placental ferritin was found to contain more acidic isoferritins, while hepatic ferritin was richer in basic isoferritins. The electrofocusing patterns of subunits revealed that placental ferritin contained at least one unique subunit on the acidic side and might lack one subunit on the basic side as compared with hepatic ferritin. It is hypothesized that microheterogeneities, immunological as well as biochemical, existing between placental and hepatic ferritins cannot be explained merely in terms of different proportions of known acidic and basic subunits, but appear to have resulted from the existence of the unique acidic subunit of placental ferritin and possibly also a unique basic subunit of hepatic ferritin.

Chromatography, DEAE-Cellulose↗
PubMed1982

Combination therapy of gastric carcinoma with radiation and chemotherapy.

The concurrent combination therapy of radiation and chemotherapy was performed in a total of 134 cases of stomach cancer. Radiation response of tumor was remarkable in 35 (37%) of 95 cases, irradiated more than 5,000 rad. Yearly survival rates in 81 cases, in which the scheduled curative treatment was completed, were 63% in one, 31% in two, 21% in three, 17% in four and 13% in five years. These rates were intimately correlated to tumor size and cancer type. However, this combination therapy accompanied some fatal complications in a few percent. From the results, it was concluded that this combination therapy should be valuable to prolong the life of patients high gastric cancer, and that the curable indications for this treatment should be T1-T3: M0 cases with radio-responsive tumor.

Adenocarcinoma↗
PubMed1982

[Cytological studies of esophageal carcinoma and gastric carcinoma receiving radiation and chemotherapy].

The cytology of the endoscopic biopsy materials from 85 cases of esophageal cancer were analyzed for effects of the combined radiotherapy with Bleomycin. Cancer cells were remarkably decreased in number after the combination therapy. Unaffected cancer cells declined to negligible levels in 64 of 79 esophageal cancer cases irradiated more than 6,000 rad. Out of 42 gastric cancer cases treated with only anticancer drugs, 37 cases exhibited hardly cytologic changes in the smears of biopsied materials. About the remnant 5 cases, cancer cells showed partially cytoplasmic swelling, nuclear enlargement and nuclear abnormal stain. The smears of the biopsy and resected specimens from 64 gastric cancer cases with radiation and chemotherapy were cytologically discussed. The combination therapy increased the amount of both necrotic materials and neutrophils in the smears. The cytoplasms of treated cancer cells were swollen, vacuolated and stained abnormally. The nuclei of cancer cells became enlarged, multiple, piknotic and/or stained pale. Nuclear swelling was more prominent in cancer cells of differentiated adenocarcinomas. Cancer cells were decreased in number almost in inverse proportion to irradiation dose. Unaffected cancer cells were disappeared in 13 of 24 cases irradiated more than 6,000 rad, in 7 of 35 cases irradiated in the range 3,000 to 6,000 rad, in none of 5 cases irradiated less than 3,000 rad.

Antineoplastic Agents↗
PubMed1982

[Radiotherapy combined with tegafur for inoperable advanced gastric cancer].

A total of 58 cases with inoperable advanced gastric carcinomas were treated by radiotherapy combined with tegafur, and the result was analyzed mainly from the aspects of life expectancies and some prognostic factors. Median survival time of all cases was 8.9 months. Actuarial survival rates at one, two, three, four and five years were 45%, 22%, 14%, 14% and 11% respectively. Cancer type, histologic type, tumor size and radiation effect on the primary lesion were chosen as the prognostic factors, and examined using median survival time as a parameter. Borrmann IV type cancer showed an unequivocally poor prognosis, whereas no significant prognostic differences were seen among other types. Poorly differentiated adenocarcinoma gave a poor prognosis. Radiation effect on the primary lesion seemed to have a positive correlation with prognosis, while life expectancies became shorter with the increase of tumor size. It seems, from the present study, that this combination therapy contributes a great deal to life prolongation of patients with inoperable advanced gastric carcinomas.

Aged↗