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Biomedical subjects

S Kobayasi

Publications and source records attributed to S Kobayasi.

At least 19 recordsLinked to original sources
PubMed2001

Radiation therapy for life- or function-threatening infant hemangioma.

PURPOSE: To assess the effectiveness and long-term results of radiation therapy in infants with life- or function-threatening hemangiomas. MATERIALS AND METHODS: Thirteen patients with life- or function-threatening hemangiomas (eight male, five female; age range, 0-8 months; median age, 2 months) were treated with radiation therapy. Life-threatening hemangiomas were treated with five fractions of radiation per week, and function-threatening hemangiomas were treated with two fractions per week. A median dose of 10 Gy was delivered to each hemangioma. The presence of residual hemangiomas, skin changes, functional problems, and growth delay was evaluated. RESULTS: All patients with Kasabach-Merritt syndrome (KMS) showed regression of the hemangioma and an increase in platelet counts to greater than 100,000 per cubic millimeter (1.0 x 10(11) per liter) within 40 days after radiation therapy. The treatment field was inadequate in two patients who required reirradiation or a change of treatment portal. With the exception of the patients with KMS, all but one patient experienced relief from symptoms in 40 days. Severe long-term radiation-related morbidity was noted in one patient who required reirradiation for a relapsed hemangioma. CONCLUSION: Radiation therapy (in doses of < or = 10 Gy in 2-Gy fractions) is indicated for life-threatening hemangiomas and for some function-threatening hemangiomas.

Adolescent↗
PubMed1999

Biological differences between reflux stimulated proliferative stomal lesions and N-methyl-N'-nitro-N-nitrosoguanidine induced carcinomas in Wistar rats.

The morphology and evolution of epithelial lesions that developed at a gastrojejunal stoma due to reflux of duodenal contents were compared with MNNG-induced carcinomas in the pyloric mucosa of rats in a long term experiment. Random bred male Wistar rats were given MNNG in drinking water (100 mg/l) for 12 weeks and then one group was submitted to a gastrojejunal anastomosis at the greater curvature in the oxyntic mucosa. Untreated rats underwent either gastrojejunostomy or gastrotomy. The animals were killed at the 24th and 66th weeks of the experiment. The lesions obtained in the pyloric mucosa and in the mucosa of the gastrojejunal stoma were analyzed histologically using hematoxylin and eosin staining and immunohistochemistry for pepsinogen isoenzyme 1. Duodenal reflux induced proliferative lesions at the gastrojejunal junction that increased in incidence and size with time. Histologically they consisted of benign epithelial proliferation of gastric type. No evidence of malignant transformation within the gastric components of the proliferative lesions at the gastrojejunal stoma was observed even at the 66th week. Adenocarcinomas induced by MNNG in the pyloric mucosa increased in size during the experiment and were morphologically and histochemically distinct from the proliferative lesions at the gastrojejunal junction. In conclusion, proliferative lesions at the gastrojejunal stoma stimulated by duodenal reflux are biologically distinct from adenocarcinomas induced by MNNG in the pyloric mucosa. They do not seem to be precursor lesions of gastric carcinogenesis, as they do not undergo malignant transformation even after long-term, up to 66 weeks, follow-up.

Adenocarcinoma↗
PubMed1999

[Clinical study of grade 3, superficial transitional cell carcinoma of the urinary bladder].

PURPOSE: To evaluate the treatment of grade 3 superficial (stage pTa and pT 1) transitional cell carcinoma (T.C.C.) of the urinary bladder, retrospective analysis was performed with special reference to tumor prognostic factors. MATERIALS AND METHODS: From July 1971 to september 1995, 51 cases with grade 3 superficial T.C.C. of the urinary bladder were treated. The survival rates and prognostic factors of these patient were analyzed. RESULTS: Five year survival rate of grade 3, superficial tumors was 92.3% and showed significantly better prognosis compared to patients with pT 2 and pT 3 tumors of grade 3 (p < 0.001). As a initial treatments, transurethral resection (TUR) was conducted in 45 patients (88%). Intravesical recurrence was observed in 20 of 45 patients (44%) and 12 of 20 patients (60%) were recurred within 1 year. Non-recurrent rates of the patients treated with TUR were 69.6% at 1 year, 58.8% at 3 year, 49.7% at 5 year, respectively. No significant differences were noted regarding factors of tumor size, figures and a number of tumor. Of the 51 patients, 10 (19.6%) progressed beyond stage T 2 and 6 died with the disease. Survival rates at 10 years follow up in patients with non-papillary and papillary tumor were 57.1% and 97.8%, respectively. CONCLUSION: These results suggested that TUR should be performed as a initial treatment for the patients with grade 3 superficial T.C.C. of the urinary bladder. However, non-papillary tumors should be considered of more intensive treatment like as radical cystectomy, adjuvant chemotherapy or irradiation.

Adult↗
PubMed1994

Gastric and small intestinal lesions after partial stomach resection with Billroth II or Roux-en-Y reconstruction in the rat.

The evolution and phenotypic expression of mucosal lesions of the gastric stump were investigated in male rats submitted to gastric resection with reconstruction by the Billroth II technique (BII with biliopancreatic reflux, BPR) or by the Roux-en-Y procedure (without BPR). Animals were studied at 24, 36, 54 and 64 weeks after surgery and the phenotypic expression of lesions analysed using routine hematoxylin and eosin staining, immunohistochemical staining for pepsinogen isoenzyme 1 and histochemical procedures for mucins (paradoxical concanavalin A, galactose oxidase Schiff (GOS) and sialidase GOS reactions). BPR was found to be responsible for the formation of adenomatous hyperplasia (AH), increasing in incidence and size with time, since the Roux-en-Y procedure failed to induce the gastric stump lesions observed after BII reconstruction. AHs always occurred in the transition of the gastrojejunal junction, a site offering special conditions for BPR influence, and were classified as gastric (G), intestinal (I) and G+I types according to their phenotypic expression. No pure I type AH was diagnosed at any time point. The G and G+I types developed at approximately equal incidences (i.e., G type 7/17, G+I type 10/17 at the 64th week). It was suggested that both gastric and intestinal mucosal elements were stimulated to proliferate by BPR, with the gastric mucosa tending to demonstrate AH. Intestinal type components of AH were found adjacent to the jejunum and not at the stomach margin, indicating an origin from intestinal mucosa. No metaplasia of the gastric mucosa was observed in any animal after partial gastric resection. In 101 rats submitted to the BII procedure, 5 mucinous adenocarcinomas were eventually diagnosed, mostly located in the subserosa of the gastrojejunal junction. All carcinomas expressed the phenotype of cells of the small intestine. Evidence of malignant transformation within the gastric components of AH was not observed even at the 64th week. In conclusion, all lesions induced by BPR in the rat remnant stomach are benign, and the few true cancers that arise in association are derived from the small intestine.

Animals↗
PubMed1993

Altered foci of hepatocytes in rats initiated with diethylnitrosamine after prolonged fasting.

The influence of fasting on the potential of diethylnitrosamine (DEN) to initiate liver carcinogenesis was tested in a medium-term assay using the development of putative preneoplastic altered foci of hepatocytes (AFH) as the endpoint. Male Wistar rats fasted for 48 hr were given a single ip injection of DEN (200 mg/kg body weight). Partial hepatectomies were carried out at wk 3 and the rats were killed at wk 8. Fasted rats exhibited a small increase in the numbers of AFH with glutathione S-transferase in the placental form and eosinophilic AFH when compared with non-fasted animals. However, after a 6-wk exposure to 0.05% sodium phenobarbital in the diet, there were no differences in the numbers of AFH between fasted and non-fasted animals. Fasting also increased DEN-dependent centrilobular cell necrosis and specifically drug metabolism as indicated in vivo by a decreased time of paralysis of the lower limbs induced by zoxazolamine (40 mg/kg body weight, ip) and by an unaltered sleeping time induced by sodium pentobarbital (40 mg/kg body weight, ip). The results indicate that although fasting during the initiation stage of carcinogenesis increases DEN hepatoxicity, it does not interfere quantitatively with the development of liver preneoplastic lesions.

Animals↗
PubMed1993

Study of the torque of the bacterial flagellar motor using a rotating electric field.

Bacterial flagella are driven by a rotary motor that is energized by an electrochemical ion gradient across the cell membrane. In this study the torque generated by the flagellar motor was measured in tethered cells of a smooth-swimming Escherichia coli strain by using rotating electric fields to determine the relationship between the torque and speed over a wide range. By measuring the electric current applied to the sample cell and combining the data obtained at different viscosities, the torque of the flagellar motor was estimated up to 55 Hz, and also at negative rotation rates. By this method we have found that the torque of the flagellar motor linearly decreases with rotation rate from negative through positive rate of rotation. In addition, the dependence of torque upon temperature was also investigated. We showed that torque at the high speeds encountered in swimming cells had a much steeper dependence on temperature that at the low speeds encountered in tethered cells. From these results, the activation energy of the proton transfer reaction in the torque-generating unit was calculated to be about 7.0 x 10(-20) J.

Biomechanical Phenomena↗
PubMed1993

Intra-GBM site of the functional filtration barrier for endogenous proteins in rats.

The passage of various endogenous proteins [such as albumin, transferrin, immunoglobulin G (IgG), and immunoglobulin M (IgM)] across GBM was studied in vivo in normal Munich-Wistar rats. Glomeruli were fixed by three different methods: in situ drip-fixation, perfusion- and immersion-fixation; then they were processed for immunogold electron microscopy. The most reproducible results were obtained with in situ drip-fixation. Albumin, transferrin and IgG penetrated into GBM, but IgM did not. Morphometry revealed that density of albumin increased towards the inner 1/5 to 1/3 of GBM (junction of lamina rara interna and lamina densa) and decreased towards the subepithelial region of GBM, whereas density of IgG and transferrin was the highest at the subendothelial site and declined towards the subepithelial side of GBM. These findings suggest that central and/or outer zone of GBM constitute the main filtration barrier for albumin, and that subendothelial zone may contribute also to the charge-selective barrier. It is also suggested that the subendothelial zone acts more effectively as a filtration barrier for IgG and transferrin than for albumin. In the outer zone of GBM, which roughly corresponds to lamina rara externa visualized by conventional electron microscopy, the relative density of IgG and transferrin was higher than that of albumin. Since the pI of albumin was lower than that of IgG and transferrin, this finding suggests that subepithelial zone of GBM also acts as a charge-selective barrier. In conclusion, the main GBM filtration barrier for albumin might be the central and outer zones of GBM, and that for transferrin and IgG might be the entire width of GBM.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1993

Reduction of cell proliferative activities of gastric stump adenomatous hyperplasias after bile reflux diversion in rats.

Previously we reported the majority of lesions induced by bile reflux, in the absence of chemical carcinogens, in the rat remnant stomach to consist primarily of gastric type and secondarily of intestinal type cells, and that they are reversible after diversion of bile reflux. The present study was designed to evaluate changes in proliferative activities in cells of each type under these conditions. The frequency of adenomatous hyperplasia (AH) induced in the gastric stump mucosa by duodenal content reflux after Billroth II partial gastrectomy (BII) increased until the 54th week of the experiment. Roux-en-Y (RY) surgical procedure which prevents duodenal reflux performed at the 24th or 36th week after BII led to a decrease in AH. Cell content of the lesions was analyzed using routine H&E staining, immunohistochemical staining for pepsinogen isoenzyme 1 and histochemical procedures for mucins (paradoxical concanavalin A, galactose oxidase Schiff and sialidase galactose oxidase Schiff reactions) and proliferation in each compartment evaluated by an immunohistochemical method using bromodeoxyuridine (BrdU) and a monoclonal antibody against BrdU. At the 54th week the number of BrdU-labeled cells per normal pyloric column was significantly (P < 0.05) increased to 10.63/pit after the BII operation, while it diminished to 5.23/pit after RY diversion, this being the same level as with the RY procedure alone. AH maintained a high rate of BrdU incorporation at 12.7% after BII operation, which was also significantly reduced (P < 0.01) to 7.0% by the RY surgery. The intestinal type cell showed highest (22.2%), the surface mucous type cell showed the next (16.5%) and the pyloric gland type cell showed lowest (5.2%) BrdU labeling indices after BII operation. All the cell types in AH showed similar proportional decreases in BrdU incorporation after RY diversion. Thus surgical intervention reverses the cell proliferation caused by bile reflux in the gastric stump.

Adenocarcinoma, Mucinous↗
PubMed1992

Toxic dilatation of the colon in Chagas' disease.

Toxic megacolon occurs in colitis of differing aetiology. This report describes 15 patients with chagasic megacolon with this complication. The clinical signs and symptoms in all patients were pain and progressive abdominal distension accompanied by fever, severe toxaemia and shock. Seven patients developed this clinical pattern after manual removal of faeces. The remaining patients had pain and abdominal distension followed by signs of severe toxaemia when first examined. Nine patients underwent total colectomy with ileostomy (one death), four partial colectomy (all died) and two received medical treatment (both died). At autopsy, three of the four patients undergoing partial colectomy had residual colitis and enteritis. The surgical procedure of choice for this complication of chagasic megacolon is total colectomy.

Adult↗
PubMed1992

Purification and characterization of an antibiotic substance produced from Rhizopus oligosporus IFO 8631.

We obtained a purified antibiotic protein from the submerged cultivation broth of Rhizopus oligosporus IFO 8631 by using CM-Cellulofine chromatography and HPLC. The antibiotic did not show a broad spectrum of activity, but it was very active against some of the Bacillus species, especially against Bacillus subtillis (B. natto) at a very low concentration (less than 1 ppm). It also showed activity against other gram-positive bacteria, including Staphylococcus aureus and Streptococcus cremoris. The purified antibiotic was a simple protein of about 5,500 in molecular weight, the amino acid component being characteristically high in cystine content. This high cystine content contributed to the stability of the antibiotic over a wide pH range and against strong heating (50% of the activity remained after boiling for 1 hr).

Amino Acids↗
PubMed1991

Reversibility of adenomatous hyperplasia in the gastric stump after diversion of bile reflux in rats.

Morphological and phenotypical patterns of proliferative epithelial lesions induced in the gastric stump mucosa by duodenal content reflux after Billroth II partial gastrectomy (BII) were evaluated in rats. Control animals were either sham-operated or submitted at different times after BII to Roux-en-Y (RY) surgical procedure which prevents duodenal reflux. The lesions were analysed using routine haematoxylin and eosin staining, immunohistochemical staining for pepsinogen isoenzyme 1 and histochemical procedures for mucins (paradoxical Concanavalin A, galactose oxidase Schiff and sialidase galactose oxidase Schiff reactions). Mucosal hyperplasia (H) was observed in the group submitted to BII procedure 6 weeks after surgery. Adenomatous hyperplasia (AH) also appeared 6 weeks after induction of the reflux and its incidence and size increased until the 54th week of the experiment. RY procedure performed in the normal animals at the beginning of the experiment or at the 24th week after BII gastrectomy led to a significantly lower incidence of AH which was related to the moment of surgery. Most of H was due to pyloric mucosal hyperplasia. AH consisted mainly of gastric type glands but in some animals glands of the intestinal type were present probably originating from the intestinal mucosa. Six mucinous adenocarcinomas were observed, all of them of intestinal type. This study demonstrates that AH induced by BII procedure is a reversible lesion and that the anomalous epithelial proliferation in the stoma may lead to adenocarcinomas.

Anastomosis, Roux-en-Y↗
PubMed1989

[Clinical effects of Juzendaiho-to on immunologic and fatty metabolic states in postoperative patients with gastrointestinal cancer].

Juzen-daiho-to is one of the Chinese traditional medicines which is usually applied with patients suffering from anemia or chronic exhaustive disease. Twenty-three patients after gastrectomy and 16 patients after colectomy were studied for NK cell activity, blastogenesis by PHA, several T-lymphocyte subsets, serum triglyceride and serum lipo-protein before drug administration at one, three, six, nine months and one year after the start of drug administration respectively. A remarkable elevation in NK cell activity was noted 3 and 6 months after the drug administration. Statistical analysis shows a significant converse correlation between NK cell activity and lipo-protein value in the group given Juzendaiho-to.

Animals↗
PubMed1989

[Efficacy of etoposide in bone metastasis of breast cancer].

We have used ADM, MMC, CDDP and other drugs for a case of bone metastasis of breast cancer, but the bone destruction was advanced and she could not walk. We have also used etoposide, a new chemotherapeutic drug, for the same case. Two months later bone sclerosis was seen by X-ray film and pain disappeared. Bone sclerosis then advanced after 6 months, she has begun to stand, and after 8 months she has been able to walk with a cane. There was no severe side effect. Etoposide was very effective for bone metastasis of the breast cancer.

Bone Neoplasms↗
PubMed1988

Light scattering measurements of the gels of gelatin and acto heavy meromyosin solutions by sample rotation method.

The gelation processes of gelatin and acto heavy meromyosin solutions were investigated by a new method of light scattering. The sample was given a constant slow rotation around a vertical axis in a typical dynamic light-scattering setup. The measurements were made on solutions in which polystyrene latex spheres were added as the scattering probes. When a sample reached the gel state, the intensity of the light scattered from the sample fluctuated highly. The relative standard deviation of the intensity fluctuation has been shown to be a good measure of gelation. In addition, computer simulations of this scattering system were found to simulate well the experimental results.

Computer Simulation↗