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Biomedical subjects

S Hirata

Publications and source records attributed to S Hirata.

242 records · Page 14Linked to original sources
PubMedDate not supplied

Endotoxin is not an essential mediator in toxic shock syndrome.

The hypothesis that toxic shock syndrome toxin 1 (TSST-1) exerts its deleterious effects in toxic shock syndrome (TSS) primarily by enhancing the lethality of small amounts of endogenous endotoxin derived from mucosal colonization with gram-negative bacteria was assessed by evaluating two means of inactivating endotoxin in rabbit models of TSS. In both of these models, toxins and TSST-1 are allowed to diffuse constantly from a subcutaneous depot. Immunologic inactivation of endotoxin with antiserum to the core lipopolysaccharide did not change the clinical course or mortality among animals infected with live TSS-associated staphylococci or among animals with a subcutaneous depot of TSST-1. Anti-TSST-1 was successful in preventing disease and death in these models. Pharmacologic inactivation of endotoxin by pretreatment or continuous treatment with polymyxin B did not prevent illness or mortality in the toxin depot model. Endotoxin thus appears not to be an essential mediator in TSS, since TSS-like illness develops and progresses despite inactivation of endotoxin in animal model systems that are faithful both physiologically and clinically to TSS in humans.

Animals↗
PubMedDate not supplied

Effects of azoxymethane on X-ray induced intestinal metaplasia in Donryu rats.

The present study was undertaken to determine the effect of azoxymethane (AOM) administration on intestinal metaplasia induced by X-irradiation in male Donryu rats. Five-week-old animals were X-irradiated with two doses of 10 Gy each at a 3-day interval or three X-ray doses of 10 Gy at a 2-day interval and then received AOM injections i.m. at a dose of 15 mg/kg body weight once weekly for 3 weeks, 6 months after irradiation. Alkaline phosphatase positive foci were decreased after AOM treatments, but aberrant crypt like-foci appeared within areas of intestinal metaplasia. In contrast no induction was observed in normal-appearing gastric mucosa.

Alkaline Phosphatase↗
PubMedDate not supplied

No susceptibility of colon tissue implanted into the glandular stomach of rats to N-nitroso-N-methylurea carcinogenesis.

The present study was undertaken to determine the response of colonic mucosa implanted into the stomach fundus in 6-week-old male F344 rats to oral administration of N-nitroso-N-methylurea (MNU). In graft + MNU, 15% animals had tumors in the implanted colon tissue whereas a 26% incidence of gastric tumors was observed for the pyloric mucosa. In MNU alone, 30% of rats demonstrated gastric tumors. In graft alone 10% of tumors were observed in the grafted site but none in the pylorus. Thus while graft tissue may intrinsically have an elevated risk of tumor development, no susceptibility to MNU was observed in the present study.

Animals↗
PubMedDate not supplied

Induction of ovarian tumors by heavy ion irradiation in B6C3F1 mice.

Six-week-old B6C3F1 mice were exposed to 0.439 Gy heavy ion irradiation as a 290 MeV/u carbon-ion beam (LET 10 keV/micron) at 2 cm from the upper proximal point of a spread Bragg beam and autopsied 13.5 months after the irradiation. In males total tumor incidences, mainly liver tumors, were 37.0% in irradiated group and 25.0% in control (P>0.05). In females the total tumor incidences were 32.3%, mainly ovarian tumors, in the irradiated group and 0% in the controls. These results indicate that heavy ion irradiation induces ovarian tumors in females but does not target any organ in males.

Adrenal Glands↗
PubMedDate not supplied

Influence of concomitant miso or NaCl treatment on induction of gastric tumors by N-methyl-N'-nitro-N-nitrosoguanidine in rats.

Six-week old male Sprague-Dawley (CD) rats were treated with 100 ppm N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) for 16 weeks in their drinking water with control, miso or sodium chloride (NaCl) supplemented diets. All animals were autopsied 12 months after the beginning of the MNNG treatment. Despite higher intake of MNNG in the high dose miso and NaCl groups, the total tumor incidences were decreased compared to middle and lowest values. The glandular stomach adenocarcinoma incidences in the 10% and 5% miso groups were significantly decreased as compared to those in the 2.2% or 1.1% NaCl groups, with the same concentration of NaCl.

Animals↗
PubMedDate not supplied

Epidermal growth factor receptor expression correlates with poor prognosis in non-small cell lung cancer patients with p53 overexpression.

To determine whether cancer patients with tumor suppressor gene abnormality survive for a shorter time when their growth was stimulated by growth factors, we examined 290 non-small cell lung cancer (NSCLC) specimens for p53 and epidermal growth factor receptor (EGFR) protein expressions using immunohistochemical staining. The distribution of cases by pathological stage of tumor was 155 cases of stage I, 30 cases of stage II, 96 cases of stage III and 9 cases of stage IV. Pathological types were 142 adenocarcinomas, 127 squamous cell carcinomas, 17 large cell carcinomas and 4 other types of malignancy. Immunohistochemical staining was performed on the formalin fixed, paraffin-embedded materials with monoclonal antibodies DO-7 and clone EGFR.133. positive staining for EGFR was seen in 124 (42.8%) cases. More EGFR positive cases were found in squamous cell carcinomas than in non-squamous cell carcinomas (p=0.0121). Staining for p53 protein was observed in 147 (50.7%) specimens. Multivariate proportional hazard model analyses revealed EGFR protein expression as a risk factor in the patients with NSCLC (p=0.0240). Patients negative for both EGFR and p53 survived for a longer period of time (p=0.0427).

Adenocarcinoma↗
PubMedDate not supplied

Superficial undifferentiated small cell carcinoma of the esophagus showing an interesting growing pattern in histology.

We report a case of superficial undifferentiated small cell carcinoma of the esophagus. The histology of the tumor was interesting; there was squamous cell differentiation within the epithelial layer and undifferentiated small cells growing within the submucosal layer. The tumor had a negative Grimelius reaction, suggesting no differentiation into a hormone-producing carcinoma known as an apudoma (Amine Precursor Uptake and Decarboxylation (APUD)). The serum levels of ACTH and calcitonin were within normal limits. As the patient was elderly and had a history of pleural tuberculosis causing poor pulmonary function, and owing to the fulminant nature of this carcinoma, he underwent blunt dissection of the esophagus by posterior mediastinal gastric pull-up. The patient recovered quickly and was able to be discharged with a good quality of life until the tumor recurred as a liver metastasis 6 months later.

Aged↗