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Biomedical subjects

S Hirota

Publications and source records attributed to S Hirota.

At least 217 records · Page 12Linked to original sources
PubMed1991

Appearance of a carcinoid-like pattern in rat hepatic tumors induced by 3'-methyl-4-dimethyl-aminoazobenzene.

This study investigated the histological distribution of argyrophilic cells in experimental hepatic neoplasms, the number of these cells, and the proportion of neoplasms with such cells. Seventy 6-week-old male Donryu rats were given a 0.06% 3'-methyl-4-dimethyl-aminoazobenzene (3'-MeDAB) diet for 10 weeks, followed by an ordinary diet for an additional 10 weeks. Of the 70 rats, 50 were used for this investigation; 29 had hepatic tumors, 18 had cholangiofibrosis, and the other three had oval cell proliferation only. Hepatic tissues were stained with Grimelius and Fontana-Masson stains as well as routine hematoxylin-eosin stain. Argyrophilic cells were found in the hepatic neoplasms of 8 rats without argentaffin cells, while cholangiofibrosis was associated with argentaffin cells in almost all cases. Of the 8 rats with argyrophilic cells, three had an abundant population of these cells. The argyrophilic cells were found in areas of the neoplasms with a glandular, trabecular, tubular, or poorly differentiated pattern. Electron microscopy revealed that the neoplastic cells with a positive argyrophil reaction contained small round electron-dense endocrine granules. In addition, in the areas of cholangiofibrosis, two different types of gut endocrine cells were present (G and EC cells). These results suggest that 3'-MeDAB might induce hepatic carcinoid under certain conditions, though we have yet to confirm the development of a pure hepatic carcinoid due to this substance.

Animals↗
PubMed1991

Possibility of heat sterilization of liposomes.

Several kinds of liposomes were sterilized at 121 degrees C for 20 min. They tended to aggregate after heat sterilization (HS) in saline, while no aggregation was observed in an isotonized sugar or polyol solution. The dispersions containing egg phosphatidylcholine (EggPC) with a high peroxide value (POV) turned slightly yellowish after HS. This color change was prevented by using EggPC with a low POV, hydrogenated EggPC (H-EggPC) or dipalmitoylphosphatidylcholine (DPPC). Nitrogen gas bubbling at neutral pH also prevented the color change, but vitamin E did not. The particle size of the EggPC liposomes extruded through a 0.4 micron membrane filter did not change significantly after HS, whereas the H-EggPC or DPPC liposomes extruded through a 0.8 micron membrane filter tended to be reduced in size. On this change the type of medium had a considerable influence. The anionic 6-carboxyfluorescein leaked from the negatively charged liposomes (EggPC/cholesterol (Chol)/egg phosphatidylglycerol) during HS, while no leakage was observed from the positively charged liposomes (EggPC/Chol/stearylamine) not only during HS but also during a long period of storage. It was suggested that sterilization of liposomes by heating was practicable as well as that by filtration, if the liposomes were prepared as follows: the charged liposomes made of lipids with low POV's were dispersed in a sugar or polyol solution adjusted to nearly pH 6.5, where the amount of dissolved oxygen was minimized. An ionic water-soluble drug had to be encapsulated in the oppositely charged liposomes.

Color↗
PubMed1991

Bone marrow-derived cultured mast cells and peritoneal mast cells as targets of a growth activity secreted by BALB/3T3 fibroblasts.

When fibroblast cell lines were cultured in contact with bone marrow-derived cultured mast cells (CMC), both NIH/3T3 and BALB/3T3 cell lines supported the proliferation of CMC. In contrast, when contact between fibroblasts and CMC was prohibited by Biopore membranes or soft agar, only BALB/3T3 fibroblasts supported CMC proliferation, suggesting that BALB/3T3 but not NIH/3T3 cells secreted a significant amount of a mast cell growth activity. Moreover, the BALB/3T3-derived growth activity induced the incorporation of [3H]thymidine by CMC and the clonal growth of peritoneal mast cells in methylcellulose. The mast cell growth activity appeared to be different from interleukin 3 (IL-3) and interleukin 4 (IL-4), because mRNAs for these interleukins were not detectable in BALB/3T3 fibroblasts. Although mast cells are genetically deficient in tissues of W/Wv mice, CMC did develop when bone marrow cells of W/Wv mice were cultured with pokeweed mitogen-stimulated spleen cell-conditioned medium. Because BALB/3T3 fibroblast-conditioned medium (BALB-FCM) did not induce the incorporation of [3H]thymidine by W/Wv CMC, the growth activity in BALB-FCM appeared to be a ligand for the receptor encoded by the W (c-kit) locus. Because CMC and peritoneal mast cells are obtained as homogeneous suspensions rather easily, these cells may be potentially useful as targets for the fibroblast-derived mast cell growth activity.

Animals↗
PubMed1991

[Lymphoscintigraphy with 99mTc-DTPA-HSA: detection of metastases to iliopelvic lymph nodes].

The purpose of this study was to evaluate 99mTc-DTPA-HSA as an iliopelvic lymphoscintigraphic agent in 5 normal volunteers and 10 patients with metastases of malignant tumors (cancer, 9; and malignant lymphoma, 1) to the iliopelvic lymph nodes. The subjects underwent intradermal injection of 185 MBq of 99mTc-DTPA-HSA into digital web spaces of the feet. Massage was applied at the injection sites for 30 sec; the subjects then walked around for 2 min. Whole-body scintigrams were obtained 5 min after injection. The whole-body scanning speed was 20 cm/min. The tracer transport was prompt. Within 15 min after injection, the tracer reached the termination of the thoracic duct in all normal volunteers. Normal whole-body images of excellent quality delineated the lymph nodes and channels almost without background radioactivity. The images of 9 patients with metastases of cancer showed clearly the following abnormal patterns: a) obstruction of lymphatic system (5/9, 55.6%); b) absence of visualization of the thoracic duct (44.4%); c) decreased uptake in lymph nodes (88.9%); d) visualization of collateral circulation (44.4%); e) tracer extravasation into more proximal soft tissue (22.2%). The image in the patient with malignant lymphoma showed increased uptake in the enlarged lymph nodes in addition to the all abnormal findings mentioned above. We concluded that 99mTc-DTPA-HSA is an excellent radiopharmaceutical for iliopelvic lymphoscintigraphy.

Adult↗
PubMed1990

[Experimental study of ferromagnetic induction heating combined with hepatic arterial embolization for treatment of liver tumors].

The induction heating to ferromagnetic implants (Ferromagnetic Induction Heating: FIH) has been developed for the purpose of selective hyperthermia on deep-seated tumors. In this investigation, the procedure of FIH combined with hepatic arterial embolization (HAE) was experimentally studied on VX2 liver tumor of rabbit. The induction heating unit is composed of radiofrequency generator (500 KHZ, 6-12 KW) and circular applicator (60 cm in diameter). Ferromagnetic implant used was pure iron particles (100 mu in size), which were suspended in tenacious polysaccharide solution to be injectable through a needle. After HAE with gelatin sponge powder had been made, iron particle suspension was injected into the cavity of tumor with subsequent exertion of induction heating (9KW) for 15 minutes. The measurement of temperature was made on the tumor and the liver parenchyma by fluoroptic thermometer with thin, flexible probe which readily passed through a needle. The temperature measured at peripheral area of tumor elevated at range from 2.5 to 7.1 degrees C, corresponding to the dose of iron particles injected; 2.5 degrees C with 1 g, 4.9 degrees C with 2 g, 7.1 degrees C with 3 g. In contrast, the temperature of liver parenchyma elevated at range of less than 2.5 degrees C, to indicate a successful selective heating of liver tumor. An additional experiment for the effect of heat on normal liver of rabbit were made using a microwave heating system. The histological and serologic examinations after heating of below 40 degrees C did not show any abnormal findings. After heating of 42-43 degrees C, however, serum GOT and GPT transiently elevated more than 3 times to that of before heating. Histologically, there were extensive degeneration and necrosis of liver tissue. From the results we concluded that FIH combined with HAE could provide an intensive therapeutic effect for treatment of well-localized liver tumors with minimal damages to the liver parenchyma, because of selective heating of the tumor.

Animals↗
PubMed1990

[Application of an angiographic catheter with side holes to intra-arterial drug infusion--improvement of drug distribution by occlusion of the catheter tip].

To improve distribution of drug by intraarterial infusion a new catheter system with sideholes, tip of which was able to be occluded by an embolus, was developed. Inner diameter of the catheter was 0.038 inch. Tip of the catheter was so smoothly tapered to 0.025 inch in inner diameter that it could be occluded by an embolus of 0.038 inch in diameter. After occlusion of the tip, drug flowed out rectangly to catheter axis from only sideholes, resulting that drug flowed out was mixtured by blood stream to make a uniform distribution of it.

Catheterization↗
PubMed1990

[Clinical study of preoperative radiotherapy of bladder cancer].

From May 1982 to Nov. 1987, 33 patients with bladder carcinoma were treated with preoperative radiotherapy (20 Gy/5fr) and total cystectomy. The over all 3-year survival rate was 70%. For T1 and T2, 3-year survival rate was 100%, but only 55% and 0% for T3 and T4 respectively. In 23 out of 33 patients, preoperative T-stage was confirmed by TUR-BT. Down-Staging was recognized in 7 out of 23 patients (30%). They were 0 out of 1 patients for Tcis (0%), 2 of 3 for T1 (67%), 3 of 6 for T2 (50%), 2 of 11 for T3 (18%) and 0 of 2 for T4 (0%). This protocol of preoperative radiotherapy is thought to be favorable for T1 and T2 bladder carcinoma, but inadequate for T3 and T4 tumors. Consequently, it is considered that higher dose radiotherapy and postoperative chemotherapy are necessary for T3 and T4 bladder carcinoma.

Adult↗
PubMed1990

Necessity of IgE antibodies and mast cells for manifestation of resistance against larval Haemaphysalis longicornis ticks in mice.

Genetically mast cell-deficient WBB6F1-W/Wv mice showed an apparent defect in manifestation of the resistance against larval Haemaphysalis longicornis ticks, but their serum IgE levels increased more than 100-fold after the second tick infestation. Immune sera obtained from the WBB6F1-W/Wv mice were adoptively transferred to the other WBB6F1-W/Wv mice which had received intracutaneous injections of WBB6F1-+/+ mouse-derived cultured mast cells. Because the resistance against ticks was detectable only when both mast cells and IgE antibodies were available, immediate hypersensitivity reaction appeared to have a physiologic role in the manifestation of the resistance against H. longicornis ticks.

Animals↗
PubMed1990

Sequential malignant transformation of cardiac myxoma.

We describe a case of cardiac myxoma in a 44-year-old Japanese man, who died after developing metastases in the skin, brain and muscle. A satellite tumor which was attached to the wall of the abdominal aorta induced marked hypertension due to obstruction of the renal arteries. Although the primary heart tumor had typical histological features of benign cardiac myxoma, the recurrent heart tumor, which was partly resected three months before the patient's death, showed apparently malignant characteristics resembling malignant fibrous histiocytoma (MFH). Since the histological features of the initial and recurrent tumors were different, the grade of malignancy was investigated using the cellularity of the tumor as an arbitrary criterion. A gradual but significant increase in the cellularity was observed over the course of five years. Immunohistochemically, tumor cells in the muscle metastasis contained vimentin and factor VIII-related antigen, and multinucleated giant cells in the recurrent heart tumor contained desmin, which is rarely detectable in MFH. Therefore, we considered that the present case represented malignant transformation of benign cardiac myxoma.

Adult↗
PubMed1990

Crystalline light-chain deposition and amyloidosis in the thyroid gland and kidneys of a patient with myeloma.

A 48-year-old Japanese woman died of multiple myeloma (lambda light-chain type) with chronic renal failure. Histological examination revealed deposition of a homogeneous substance and crystals in the kidneys and thyroid gland. The homogeneous substance was stained with Congo red after permanganate treatment but did not stain with antibody to amyloid A protein, and it was recognized as AL-type amyloid. Crystals were not stained with Congo red, but crystals were stained with antibody to the lambda light chain. Since AL-type amyloid is considered to be derived from a myeloma light chain, the present case showed two different types of deposition, both of which were derived from the same myeloma protein.

Amyloid↗
PubMed1990

[Eccentric projection for the observation of the root canals of the upper premolars].

Information on the length and the shape of the root canals is necessary in dental care. They are obtained from X-ray examination of teeth. However, it is useful to apply eccentric projection for optimization in dental radiography. We observed 135 teeth and 355 films of extracted upper premolars, and tried to establish the standard of eccentric projection for the observation of root canals of the upper premolars, on the basis of the calculations and the experiments. 1. Shapes of root canals in the upper premolars are classified into 3 types with 3 subtypes. The rate of teeth with one root was 69.6%, but the rate of teeth with two root canals was 43%. These indicate the necessity of the eccentric projection in dental radiography, although there is a limit to the ability of X-ray film for confirmation of real condition of the root canals. 2. Optimal eccentric projection angle was 20 degrees-25 degrees. There is no significant difference between the paralleling technique and bisecting technique. There is no significant difference between the mesial and distal eccentric projection. But, the mesial eccentric projection is more effective for the observation of whole root and the ease of radiographic technique than the distal eccentric projection.

Bicuspid↗
PubMed1990

[A case of candida endocarditis with consecutive measurement of serum mannan and D-arabinitol concentrations].

We encountered a case of an 83-year-old patient with candida endocarditis. He had been diagnosed as having aortic regurgitation with moderately calcified aortic valve 5 years previously, and had received medication. He was admitted to our hospital because of pancreatic cancer. He had high fever from the time of his admission and antibiotics produced no effect. Candida albicans was detected in arterial blood culture. We also detected antibody against Candida albicans, and investigated serum mannan and the D-arabinitol creatinine ratio several times. We performed echo-cardiographic examination and recorded a vegetation at the aortic valve. Rising antibody titers against Candida albicans, mannan antigenemia and an elevated creatinine ratio were also observed. So we concluded that these examinations were also effective in the diagnosis of candida infection. Finally, this patient died of cerebral hemorrhage and was autopsied. Macroscopic findings showed mass-like vegetation involving the aortic valve, and microscopic findings showed candida organisms scattered within the vegetation.

Aged↗
PubMed1990

Differences in irradiation susceptibility and turnover between mucosal and connective tissue-type mast cells of mice.

Although precursors of mast cells are derived from the bone marrow, phenotypes of mast cells are influenced by the tissues in which final differentiation occurs. Connective tissue-type mast cells (CTMC) and mucosal mast cells (MMC) are different in morphological, biochemical, immunological, and functional criteria. The purpose of the present study was to obtain information about the differentiation process of MMC. First, we compared changes in irradiation susceptibility in mice during the differentiation process of CTMC and MMC. The decrease in irradiation susceptibility was remarkable in the CTMC differentiation process, but it was moderate in that of MMC. Some morphologically identifiable CTMC in the peritoneal cavity had proliferative potential and were highly radioresistant, whereas such a radioresistant population of MMC was not detectable in the gastric mucosa. Second, we estimated the turnover of CTMC and MMC by determining the proportion of mast cells that were labeled with continuously administered bromodeoxyuridine. The turnover of MMC was significantly faster than that of CTMC. The absence of the radioresistant mast cell population in the gastric mucosa appeared to be related to the short life span of MMC.

Animals↗
PubMed1989

[Experimental study of arterial damage induced by anti-cancer drug infusion].

In order to clarify the cause of arterial changes after intra-arterial infusion of anti-cancer drugs (AI-AD) experiments were made on the arteries of rabbits. Histopathologic sections, 7 days after AI-AD revealed endothelial damage characterized by pyknosis, hyalinization with edematous change of the intimal layer. Proliferation of the endothelial cells was also observed. The cause of narrowing or occlusion of the arteries was considered to occur with thrombus formation surrounded by the proliferated endothelial cells and this suggested that thrombolytic agents would be effective to prevent these arterial changes.

Animals↗
PubMed1989

[Experimental study of embolo-hyperthermia for treatment of liver tumor--induction heating to ferromagnetic particles injected into tumor tissue].

Hepatic arterial embolization was performed on VX2 liver tumor of rabbit with subsequent induction heating to the tumor. Prior to the heating, iron particle suspension was injected into tumor tissue as a target of induction heating (500 KHZ, 9 KW). The temperatures of the tumor and liver parenchyma were measured with fluoroptic thermometer. Elevation of the tumor temperature during initial heating for 6 minutes were well correlated to the dose of iron particles injected; 1.4 degrees C with 1 g, 3.0 degrees C with 2 g, and 4.9 degrees C with 3 g. The temperature of liver parenchyma were below 39 degrees C even with 3 g injection.

Animals↗