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Biomedical subjects

M Onishi

Publications and source records attributed to M Onishi.

At least 19 recordsLinked to original sources
PubMed1996

Identification of an oncogenic form of the thrombopoietin receptor MPL using retrovirus-mediated gene transfer.

Thrombopoietin and its receptor (MPL) are important regulators of megakaryopoiesis. We have identified an activating mutation of MPL using a combination of a retrovirus-mediated gene transfer and polymerase chain reaction-driven random mutagenesis. This point mutation causes a single amino acid substitution from Ser498 to Asn498 in the transmembrane region and abrogates factor-dependency of all interleukin-3-dependent cell lines tested. Murine interleukin-3-dependent Ba/F3 cells expressing the mutated but not the normal form of MPL were tumorigenic when transduced into syngeneic mice. Analysis of intracellular signaling pathways indicated that the mutant MPL protein constitutively activated two distinct signaling pathways, SHC-Raf-MAPK and JAK2-STAT3/STAT5.

Animals↗
PubMed1996

Applications of retrovirus-mediated expression cloning.

We have recently established a novel expression cloning system using retroviral vectors. The system is based on a high-efficiency packaging cell line, BOSC23, and a simplified retroviral vector, pBabeX, carrying no selection marker. cDNA libraries, constructed in the pBabeX vector, are transiently transfected into BOSC23 cells. The supernatant contains more than 3X10(6)/mL, which would cover large complexities of cDNA libraries. The retrovirus stock gave 100% infection efficiency in NIH3T3 cells and 5-40% infection efficiency in various hematopoietic cell lines. In contrast to the conventional expression cloning system, in which it is necessary to transfect cDNA libraries transiently into particular cell types such as COS cells, retrovirus-mediated expression cloning allows us to transduce cDNAs into a wide variety of cell types. This method therefore makes it possible to select cells expressing a cDNA of interest by various functional assays. When combined with polymerase chain reaction (PCR)-driven random mutagenesis, this system is also useful in searching for mutations of various molecules that will result in alterations of their functions.

3T3 Cells↗
PubMed1996

Cytolysis of B-16 melanoma tumor cells mediated by the myeloperoxidase and lactoperoxidase systems.

Halide-dependent cytolysis of B-16 melanoma cells mediated by myeloperoxidase and lactoperoxidase systems was observed by turbidimetry. A significant decrease in turbidity, which is indicative of cytolysis, was found when a system consisting of myeloperoxidase, a source of hydrogen peroxide (glucose+glucose oxidase), and chloride or bromide were added to a B-16 melanoma cell suspension in the pH 4.7-6.0 region. The myeloperoxidase could be replaced by lactoperoxidase in the system containing bromide, but not that containing chloride. B-16 melanoma cells exposed to myeloperoxidase or lactoperoxidase systems at pH 5.5 or 7.0 were implanted by subcutaneous inoculation into C57BL/6CrSlc mice. After 14 days, a significant suppression of the growth of black tumors was detected in the groups of mice inoculated with melanoma cells exposed to the systems containing myeloperoxidase, glucose, glucose oxidase and chloride or bromide, or the system containing lactoperoxidase, glucose, glucose oxidase and bromide, at pH 5.5, but no significant suppression was observed at pH 7.0. From these findings, we concluded that the exposure of B-16 melanoma cells to a system consisting of myeloperoxidase, hydrogen peroxide (generated by the glucose+glucose oxidase system) and chloride or bromide, or of lactoperoxidase, the hydrogen peroxide and bromide, at moderately acidic pH, causes cytolysis is accompanied by cell death.

Animals↗
PubMed1995

Efficient screening of retroviral cDNA expression libraries.

Expression cloning of cDNAs was first described a decade ago and was based on transient expression of cDNA libraries in COS cells. In contrast to transient transfection of plasmids, retroviral gene transfer delivers genes stably into a wide range of target cells. We utilize a simple packaging system for production of high-titer retrovirus stock from cDNA libraries to establish a cDNA expression cloning system. In two model experiments, murine interleukin (IL)-3-dependent Ba/F3 cells were infected with libraries of retrovirally expressed cDNA derived from human T-cell mRNA or human IL-3-dependent TF-1 cell line mRNA. These infected Ba/F3 cells were selected for the expression of CD2 by flow cytometry or for the alpha subunit of the human IL-3 receptor (hIL-3R alpha) by factor-dependent growth. CD2 (frequency, 1 in 10(4)) and hIL-3R alpha (frequency, 1 in 1.5 x 10(5)) cDNAs were readily detected in small-scale experiments, indicating this retroviral expression cloning system is efficient enough to clone low-abundance cDNAs by their expression or function.

3T3 Cells↗
PubMed1995

Analysis of antitumor properties of effector cells stimulated with a cell wall preparation (WPG) of Bifidobacterium infantis.

Intestinal Bifidobacterium species are thought to be beneficial in animal and human intestines. We studied the mechanisms of Bifidobacteria in antitumor activity using a cell wall preparation (WPG) of B. infantis (Cancer Res., 45, 1300, (1985)). WPG enhanced the in vitro antitumor activities of mouse peritoneal exudate cells elicited with proteose-peptone (P-PEC) and thioglycollate broth (TG-PEC), determined by cytostatic ([3H]thymidine uptake inhibition) and cytolytic ([3H]uridine release) assays. Tumor necrosis factor-alpha (TNF-alpha) and reactive nitrogen intermediates (RNI) play a role in such augmented cytotoxicity, because anti-TNF-alpha antibody almost completely blocked the increased cytolytic activity of P-PEC in the presence of WPG. Moreover, WPG induced RNI in the supernatant of TG-PEC in a dose-dependent manner. The mRNA expression of several cytokines (IL-1 beta, IL-6, IL-10, IFN-alpha and TNF-alpha) was induced in BALB/c mouse peritoneal cells 3 h after an intraperitoneal injection of WPG (3 h WPG-PEC). However, this expression disappeared from 24 h WPG-PEC, except for that of IFN-alpha. IFN-gamma was not induced. Kinetic studies of the tumor neutralizing activities of the WPG-PECs by means of the in vivo Winn assay revealed that the activity emerged at 1.5 h, became maximal at 3 h and disappeared at 24h. These results indicated that Bifidobacterial WPG is a Biological Response Modifier (BRM) with characteristics similar to those of other bacterial BRMs.

Animals↗
PubMed1994

Progression and regression of atherosclerotic findings in the descending thoracic aorta detected by enhanced computed tomography.

Reports evaluating the progression and regression of atherosclerosis by non-invasive procedure are still limited. We investigated the progression and regression of atherosclerotic intimal thickening of the descending thoracic aorta non-invasively measured by enhanced computed tomography in 83 patients (average age 51.0 years) at the beginning and end of a 2.5 year period. The patients were not taking anti-hypertensive, lipid-lowering or hypoglycemic drugs and therefore we consider them as a natural history cohort. At entry, the extent of aortic intimal thickening was 35.2% of the circumference of the cross-section of the wall, which increased to 39.7% after 2.5 years. Spontaneous progression was associated directly with age, elevated levels of total cholesterol, LDL-cholesterol, LDL/HDL cholesterol ratio, diastolic blood pressure, and inversely to HDL-cholesterol. There was little correlation with triglycerides, systolic blood pressure, fasting glucose or body mass index. In 65 of the patients, aortic atherosclerosis progressed, while in 9 patients it remained unchanged, and in a further 9 it regressed. The levels of lipid variables, apart from HDL-cholesterol, and diastolic blood pressure in the patients with spontaneous progression were significantly higher than in the unchanged and spontaneous regression. Thus, this study verified the natural history of aortic atherosclerosis non-invasively measured by enhanced CT.

Adult↗
PubMed1994

[Single dose toxicity study of lactitol (NS-4) in dogs].

Male beagle dogs were orally given lactitol, a hepatic encephalopathy drug, in a single dose of 7.5, 15.0 or 30.0 g/kg. Vomiting was seen within 30 minutes after dosing in all treated groups. Diarrhea was observed 3 or 5 hours after dosing in the 15.0 and 30.0 g/kg dose groups. There were no drug related effects on survival, food and water consumption, body weight gain or tissues and organs.

Administration, Oral↗
PubMed1994

[52-week oral toxicity study of lactitol (NS-4) in dogs followed by 9-week recovery test].

Five male and 5 female beagle dogs were orally given lactitol, a hepatic encephalopathy drug, for 52 weeks at doses of 0, 0.25, 1.25 or 6.25 g/kg/day. A 9 week recovery test was conducted after the discontinuation of the drug treatment. Soft stool, diarrhea, and vomiting were seen in the 1.25 and 6.25 g/kg groups. In the 6.25 g/kg group, bloody stool and increased water consumption were also observed. Urinalysis showed larger amount of the urine volume in the 6.25 g/kg group. The cecum weight of this group was increased without any morphological changes. There were no drug related effects on survival, body weight gain and food consumption. Electrocardiographic, ophthalmoscopic, hematologic and biochemical examinations failed to show any abnormalities related to the drug treatment. The above mentioned changes were satisfactorily reversible. Based on the results obtained, the NOAEL of this study was suggested to be 0.25 g/kg/day.

Administration, Oral↗
PubMed1993

CD4dull+ hematopoietic progenitor cells in murine bone marrow.

CD4+ cells comprise approximately 3% to 6% of murine bone marrow (BM) cells. The majority are CD4dull+, but there are two distinct sub populations: CD4 brightly positive Gr-1- cells (CD4hiGr-1-) and CD4+ Gr-1+ cells (CD4loGr-1lo). CD4hiGr-1- cells are considered to be mature T cells by cell surface antigen expression and morphology. CD4loGr-1lo cells, which comprise approximately 0.6% of the BM cells, express small amount of B220 and Thy1 antigens. Interestingly, colony-forming units (CFU)-spleen and CFU-C are not enriched in this population. However, when injected into lethally irradiated mice, CD4loGr-1lo cells were shown to differentiate into T-cell, B-cell, and myelo-monocyte lineages when assayed 26 weeks after transplantation. Furthermore, donor-derived CD4loGr-1lo cells were present in the recipients' BM at least 16 weeks after transplantation. These observations suggest that murine CD4loGr-1lo cells in BM have self-renewal capability and retain the ability to differentiate into at least three lineages in long-term hematopoiesis.

Animals↗
PubMed1993

[The effect of fluticasone propionate topically dosed prior to the pollen scattering season on cellular infiltration into the surface of nasal mucous membrane in patients with Japanese cedar pollinosis].

In order to examine fluticasone propionate's mechanism of inhibiting nasal allergic symptoms, topical dosing of FP to patients with Japanese cedar pollinosis was started before the pollen scattering season, and the kinetics of basophilic cells and eosinophils which infiltrated into the surface of nasal mucous membrane were observed. Patients with Japanese cedar pollinosis were divided into two groups. Before and in the early period of the pollen scattering season, one group received FP and the other group a placebo, topically into the nostrils. In the mid and late season, both groups were treated with FP topical dosing. The study was carried out in the double blind manner. In the pre-, early and late season, specimens were scraped from the nasal mucosal surface, basophilic cell and eosinophil counts in the specimens were measured, and histamine and ECP contents in the specimens were also determined. Topical use of FP starting pre-season significantly inhibited symptoms of Japanese cedar pollinosis, as well as accumulation of basophilic cells and eosinophils in the nasal mucosal surface. Histamine and ECP contents in the nasal specimens tended to decrease with the topical use of FP.

Administration, Topical↗
PubMed1992

Evaluation of morphological changes of the atherosclerotic aorta by enhanced computed tomography.

Enhanced and non-enhanced computed tomography (CT) were performed in 405 subjects (222 men; 183 women; mean age 57 years). Intimal atherosclerotic changes of the aorta were quantified by enhanced CT, revealing the atheromatous intima to be projecting and thick-walled, while non-enhanced CT demonstrated aortic calcification. We measured the degree of aortic intimal changes at various segments of the aorta. In 224 cases, CT was performed from the aortic root to the bifurcation of the abdominal aorta. Intimal changes were found predominantly at the aortic arch, the middle descending thoracic and the infrarenal abdominal aorta. As for the intimal changes, aortic calcification and aortic pulse wave velocity were significant atherosclerotic characteristics. The aortic diameter did not show a significant association with intimal change. Among the various atherosclerotic risk factors, intimal change was significantly associated with age, systolic blood pressure, serum total cholesterol and diabetes mellitus, whereas gender, diastolic blood pressure, relative weight and cigarette use were not significantly related. For coronary artery disease and arteriosclerosis obliterans, aortic intimal changes constituted a significant atherosclerotic feature. In cerebrovascular disease, however, aortic intimal change did not play a significant role.

Adolescent↗
PubMed1992

Primary mediastinal diffuse large cell lymphoma initially presented with pericardial infiltration.

A 33-year-old Japanese woman visited our hospital with progressive dyspnea. A chest roentgenogram and a chest computed tomogram revealed a mediastinal tumor and pericardial effusion. Ultrasound cardiography revealed the existence of cardiac tamponade. She was successfully treated with emergency pericardial drainage, thoracocentesis and chemotherapy. The histological diagnosis of diffuse large B cell lymphoma was established with the tumor specimen obtained by transcutaneous fine needle aspiration biopsy and through immunohistochemical analysis. This is a rare case of primary mediastinal diffuse large cell lymphoma with initial presentation of a symptom related to pericardial effusion.

Adult↗
PubMed1992

[A case of traumatic right diaphragmatic hernia diagnosed by pleurography].

The diagnosis of traumatic diaphragmatic hernia is relatively easy on the left side, but is often difficult on the right, partly because the herniated organ is usually the liver. Recently, we experienced a relatively rare case of traumatic right diaphragmatic hernia and found that pleurography was useful for its diagnosis. This case is reported here together with some discussion of the literature.

Accidents, Traffic↗
PubMed1991

MK-801 fails to modify the effect of methamphetamine on dopamine release in the rat striatum.

The effect of MK-801 at a dose of 0.5 mg kg-1, i.p., on methamphetamine-induced (MAP; 4 mg kg-1, i.p.) dopamine (DA) release was examined in the striatum of freely moving rats using an in-vivo microdialysis method. Combined treatment of MK-801 with MAP did not modify the MAP-induced increase in extracellular DA levels or the decrease in 3,4-dihydroxyphenylacetic acid levels. These findings suggest that MK-801 fails to modify the acute effect of MAP on DA release in the striatum. The blocking effect of MK-801 on the development of MAP-induced behavioral sensitization is unlikely to be mediated by DA neurons.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1989

Potentiality of protamine sulfate as mutagen.

The mutagenicity of protamine sulfate has been clarified based on chromosomal aberration of cultured chinese hamster lung cells (cell line) in direct and metabolic activation methods and microbial mutagenesis (Ames test). In chromosomal aberration test, protamine sulfate caused cytotoxicity in the high doses (2500 and 5000 micrograms/ml) in the presence of rat liver homogenates (S-9). But very negligible or no cytotoxicity occurred in direct method at high dose (5000 micrograms/ml). Structural aberration of chromosome was not occurred in either of the methods. In microbial mutagenesis study, protamine sulfate did not show any cytotoxicity to microbes up to the dose of 5000 micrograms per plate. Furthermore, it did not have any effect in microbes like mutagens or like some toxic agent. The study reveals that protamine sulfate is not mutagen.

Animals↗
PubMed1989

[Systolic time intervals in mitral valve prolapse syndrome].

Systolic time intervals (STI) were measured in 135 patients with mitral valve prolapse syndrome (MVP). These patients were categorized as Group II (no or trivial mitral regurgitation) and Group III (moderate or severe regurgitation). The controls consisted of 120 normal subjects (Group I). The Group II patients tended to have increased ETc and shortened PEP. The Group III patients tended to have prolonged Q-I and decreased QIIc and ETc, reflecting mitral regurgitation. It was suggested that autonomic nervous system, especially sympathetic nerve, may play a role in changes of STI of the Group II patients.

Adolescent↗
PubMed1989

[Anticonvulsant effects of bifemelane hydrochloride on kindled seizures from the amygdala and hippocampus in rats].

The anticonvulsant affects of bifemelane hydrochloride, a novel therapeutic drug for cerebrovascular dementia, were investigated in the kindling model of epilepsy in rats. The results obtained were as follows. (i) Both the seizure stage and afterdischarge duration of kindled seizures from the amygdala and hippocampus were significantly suppressed following systemic injection of bifemelane hydrochloride (5-30 mg/kg) in a dose-dependent manner. (ii) The efficacy of anticonvulsant action on kindled seizures from the hippocampus was more potent than from the amygdala. (iii) The maximum anticonvulsant effects were observed between 1 and 4 h after injection, and this time course was very similar to that of the previously reported increasing effects of bifemelane hydrochloride on noradrenaline levels in the rat brain. Thus, it is suggested that these anticonvulsant effects in kindling may be mediated by central noradrenergic systems. These results indicate that bifemelane hydrochloride has a potent anticonvulsant action on kindled seizures and may be useful for dementia patients with epilepsy or other seizure disorders.

Amygdala↗