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Biomedical subjects

R Izumi

Publications and source records attributed to R Izumi.

At least 19 recordsLinked to original sources
PubMed1998

Morphology of single afferents of the saccular macula in cats.

The morphology of single saccular afferents was studied by the intracellular horseradish peroxidase (HRP) method. Four neurons were sufficiently stained to allow reconstruction of their axonal arborizations. The main axon of these neurons bifurcated into an ascending and a descending branch at the level of the lateral nucleus. The ascending branches of two axons gave off collaterals with boutons in the caudal part of the superior nucleus, while the other two ascending branches lacked such terminations. By contrast, characteristics of the descending axonal arborization patterns of all the four neurons were substantially the same. The descending branches coursed caudally through the lateral part of the descending nucleus, and gave off up to 14 collaterals with boutons that extended throughout this nucleus. These collaterals also reached the ventral part of the lateral nucleus, the lateral border of the medial nucleus, and group f. A few axon collaterals ramified even outside the border of the vestibular nuclei into the spinal trigeminal nucleus and the reticular formation surrounding it. Axon collaterals from the stem axon also terminated in the interstitial nucleus of the vestibular nerve. There was a noticeable absence of any projection to the y group.

Action Potentials↗
PubMed1998

Enhancement of GABA-mediated inhibition of rat medial vestibular nucleus neurons by the neurosteroid 20-hydroxyecdysone.

In vivo electrophysiological and patch-clamp studies were performed to determine whether 20-hydroxyecdysone (20-HE), a neurosteroid, influenced neuronal activities of the medial vestibular nucleus (MVN) using chloral hydrate-anesthetized rats and dissociated MVN neurons, respectively. Single neuronal activities of MVN were extracellularly recorded with a glass-insulated silver wire microelectrode attached along a seven-barreled micropipette. Each micropipette was filled with 20-HE, glutamate, bicuculline or 2 M NaCl. These chemicals were applied microiontophoretically to the immediate vicinity of the target neurons. Microiontophoretically applied 20-HE (20-80 nA) dose-dependently decreased rotation-induced firings of both type I and II neurons, which were identified according to their responses to horizontal sinusoidal rotations. Microiontophoretically applied bicuculline, a GABAA receptor antagonist, inhibited 20-HE-induced decreases in neuronal firing of MVN. These findings suggest that 20-HE potentiates the action of GABA, probably by acting directly on the GABAA receptor of MVN neurons. In addition, microiontophoretically applied 20-HE decreased firings induced by glutamate in both type I and II neurons. This decrease by 20-HE was also antagonized with bicuculline. Furthermore, the effects of 20-HE on GABA-induced currents in acutely dissociated MVN neurons were investigated using the whole-cell patch-clamp technique. Under voltage-clamp conditions, GABA (10 microM)-induced currents were potentiated in the presence of 20-HE (100 microM). These findings suggest that 20-HE inhibits MVN neurons by acting on the modulatory site on GABA receptor-ion channel complexes to potentiate GABA inhibition.

Animals↗
PubMed1998

[Evaluation of a new anti-cancer drug regimen for endometrial cancer].

BACKGROUND: The purpose of this study was to describe a new anti-cancer drug regimen for endometrial cancer. METHODS: The cytotoxicities of some anti-cancer drugs regimens against human endometrial cancer xenografted into nude mice (TEI, TET, TEU, TEN) have been studied. The activities of ADM, CDDP, CPM, CPT-11, TXL, CDDP + ADM, CDDP + CPM, CDDP + CPT-11, CDDP + TXL, CPT-11 + TXL were evaluated in comparison with a control group using saline. Three mice were used for each group, and when xenografted tumor reached 6 mm of its diameter, 1/5 LD50 of these drugs was administered into the periotoneal cavity mice once a week for three weeks. RESULTS: The effective regimens were CPT-11 + TXL, CDDP + CPT-11, CDDP + CPM, CDDP + TXL for the endometrial cancer. CONCLUSIONS: It is suggested that these new drugs regimens should be tested in clinical studies.

Animals↗
PubMed1998

[Evaluation of a new anti-cancer drug regimen for surface epithelial-stromal ovarian cancer].

BACKGROUND: The purpose of this study was to describe a new anti-cancer drug regimen for epithelial ovarian cancer. METHODS: The cytotoxicities of some anti-cancer drugs regimens against human epithelial ovarian cancer xenografted into nude mice (TOM, TOH, TON) have been studied. The activities of CDDP, CPT-11, TXL, CDDP + CPM, CDDP + CPT-11, CDDP + TXL, CPT-11 + CPM, CPT-11 + TXL, and TXL + CPM were evaluated comparing with a control group using saline. Three mice were used for each group, and when the xenografted tumor reached 6 mm in diameter, 1/5 LD50 of these drugs was administered into the peritoneal cavity of mice once a week for three weeks. RESULTS: The three most effective regimens were CPT-11 + TXL, CDDP + CPM, and CDDP + CPT-11 for epithelial ovarian cancer.

Adenoma↗
PubMed1997

Odontogenic myxofibroma arising from the periodontal ligament in the maxillary molar region.

A rare case of odontogenic myxofibroma, which arose from the periodontal ligament and expanded into the oral cavity resulting in an epulis-like lesion in a 52-year-old man, is reported including details of studies using lectin histochemistry, transmission electron microscopy (TEM), and immunohistochemistry. Most of the tumor cells, which appeared spindle-like with abundant rough endoplasmic reticulum and some microfilaments by TEM, showed immunoreactivity for mesenchymal markers. Some tumor cells, which were polygonal and contained many microfilaments and some filament bundles, were immunoreactive for muscle markers. The present case was considered to consist of many fibroblasts and some myofibroblasts.

Bicuspid↗
PubMed1997

[Effect on 5'-deoxy-5-fluorouridine (5'-DFUR) of pyrimidine nucleoside phosphorylase (PyNPase), matrix metalloprotease and serum IAP values. Hokuriku Colorectal Cancer Chemotherapy Study Group].

PyNPase activity, MMPs activity and serum IAP values were measured in tumor tissues from colorectal cancer patients who had been divided into two groups, one given preoperative 5'-DFUR and the controls. PyNPase activity of the preoperative administration group was approximately equivalent to that of the controls. In the control group, correlations were assessed between PyNPase activity and activities of MMP1 and MMP3. To assess the effect of 5'-DFUR on the activity of MMPs, we divided patients into two groups, a high and a low PyNPase activity group. Although there was no correlation with MMPs activity of the preoperative administration group and the control group in the low PyNPase activity group, the activities of MMP1 and MMP9 of the control group were significantly higher in the high PyNPase activity group. Moreover, the serum IAP value of the administration group was significantly lower than that of the control group. These results indicated that PyNPase activity was thus suggested to be somehow related to MMPs activity and serum IAP values.

Adult↗
PubMed1997

[Evaluation of a new anti-cancer drug regimen against uterine cervical cancer in nude mice].

The purpose of this study was to describe a new anti-cancer drug regimen for uterine cervical cancer. The cytotoxicities of some anti-cancer drugs regimens against the human uterine cervical cancer xenografted into nude mice have been studied. The activities of CDDP, CPT-11, TXL, CDDP + BLM, CDDP + MMC, CPT-11 + BLM, CPT-11 + CDDP, CDDP + 5-FU, CPT-11 + MMC, CPT-11 + TXL and CDDP + TXL for squamous cell carcinoma (TCR, TCK, TCG), and CDDP, MMC, TXL, CDDP + TXL, CDDP + MMC and MMC + TXL for adenocarcinoma (TCO, TCM, TCY), were evaluated comparing with a control group using saline. Five mice were used for each groups. When the xenografted tumor reached 6 mm in diameter, 1/5 LD50 of these drugs were administered into the peritoneal cavity of the mice once a week for three weeks. The effective regimens were CDDP + MMC, CDDP + BLM, CDDP + CPT-11 and CPT-11 + MMC for squamous cell carcinoma of the uterine cervix. CDDP + MMC, CDDP + TXL, MMC + TXL and CDDP were effective for endocervical adenocarcinoma. It was suggested that these new drug regimens should be used in clinical studies.

Adenocarcinoma↗
PubMed1997

[Antinociceptive activity of intracisternal clonidine in the mouse].

The antinociceptive activities of clonidine have been determined against three qualitatively different noxious stimuli in the mouse. The methods used to evaluate this activity were selected to include tests which employ different types of noxious stimuli, i.e. heat (hot plate), chemical (acetic acid-induced writhing) and mechanical (tail pinch). Test drug and control treatments were given by cisternal injection in a dose volume of 10 microliters.mouse-1. The results presented here show that clonidine has potent antinociceptive properties against several types of noxious stimuli. Clonidine produced steep dose-response lines in all tests. The response to the writhing assays were completely inhibited by 1.0 microgram.mouse-1 of clonidine. In contrast in both the hot plate and tail pinch assay, however, clonidine did not produce a consistent antinociceptive effect at a dose of 200 micrograms.mouse-1. Utilizing these three different types of assays, the rank order of antinociceptive potency for clonidine in different noxia was the writhing >> hot plate > tail pinch. It was concluded from these results that clonidine has potent antinociceptive properties against chemical visceral stimuli.

Adrenergic alpha-Agonists↗
PubMed1997

Characterization of a newly established human tumor cell line (TEN) from a patient with clear cell carcinoma of the uterine body and its sensitivity to anti-cancer agents.

A cell line derived from human endometrial clear cell adenocarcinoma was newly established and named TEN. The tumor cells were obtained from uterine body of a 74-year-old who had been undergone an abdominal simple hysterectomy. The histologic features of the tumor cells showed abundant clear cytoplasm with diastase digested glycogen granule growing in solid nest and tubular pattern. The TEN cells were continuously propagated in vitro during the past 45 months and they were at 75th passage. They grew in a monolayered sheet with a doubling time of about 53 hours. The TEN cells resembled the structure of the original tumor and had abundant glycogen granules, lipid droplets in the cytoplasm. The histopathology of the transplanted tumor in SCID mice resembled that of the original tumors. The TEN cells secreted a high content of CA125. Immunohistochemically, the TEN cells had c-erbB-2 and Cathepsin D immunoreactivity in some parts of the cell population. But they did not have estrogen, progesterone and EGF receptor. Sensitivities of the TEN cells to a variety of anti-cancer drugs were examined. In in-vitro tests, MTT assays employed. The results suggested that the TEN cells were not sensitive to any of 13 agents. On the other hand, in-vivo sensitivity test of transplanted tumor in SCID mice, the tumors were sensitive to CPT-11 and paclitaxel. We conclude that the TEN cell line will be effective material for chemosensitivities against the endometrial clear cell adenocarcinoma.

Adenocarcinoma, Clear Cell↗
PubMed1996

Production of polyclonal antibody specific for human natriuretic peptide receptor B.

Polyclonal antibody against human natriuretic peptide receptor B (NPR-B) was produced using as immunogen a soluble chimeric protein consisting of the extracellular domain of the receptor fused with Fc portion of human IgG. The antibody was purified with protein A column, and then subjected to an adsorption of anti-Fc antibody using IgG column. The purified antibody recognized human NPR-B but not the related receptor NPR-A. The antibody inhibited C-type natriuretic peptide (CNP)-mediated intracellular cGMP accumulation in a dose-dependent manner. With regard to specific activity for the neutralization, the antibody purified with IgG column was significantly stronger than that before the adsorption step, indicating that the purification of the antibody with IgG column was extremely effective to remove the contaminating anti-Fc antibody from anti-NPR-B antibody. Western blot analysis using the purified antibody revealed that while the native NPR-B exists as an oligomer, the truncated NPR-B lacking most of its cytoplasmic domain is a monomer. This finding suggests that the cytoplasmic region may be involved in the oligomerization of the receptor. The results in this study demonstrate that soluble IgG fusion protein is very effective and useful for generating specific antibodies to the proteins expressed on cell surface.

Animals↗
PubMed1996

The immunosuppressive effects of a leukotriene B4 receptor antagonist on liver allotransplantation in rats.

The immunosuppressive effects of a leukotriene B4 (LTB4) receptor antagonist, ONO4057, on liver allotransplantation in rats were evaluated, and the levels of prostaglandin E2 (PGE2) in the liver tissue during rejection of the allografts examined. The rats were divided into four groups: group 1: Lewis rats (LEW) given a sham operation with dimethyl sulfoxide (DMSO); group 2: LEW given syngenic orthotopic liver transplantation (OLT) from LEW, with DMSO; group 3: LEW given allogenic OLT from ACI rats (ACI), with DMSO; and group 4: LEW given allogenic OLT from ACI, with ONO4057 as 10, 30, or 100 mg/kg per day dissolved in DMSO to subgroups 4a, 4b, and 4c, respectively. Histological examinations were performed, survival times monitored, and liver tissue PGE2 levels 3, 5, 7, and 14 days after transplantation measured. The mean graft survival times in groups 4a, b, and c, at 37.5 +/- 10.4, 52.2 +/- 24.4, and 34.0 +/- 4.9 days (mean +/- SEM), respectively, were significantly longer than that in group 3 (at 13.0 +/- 3.2 days). Moreover, the levels of tissue PGE2 in the liver allografts in group 4a were significantly higher than those in group 3 on days 5 and 7. These results suggest that ONO4057 has an immunosuppressive effect on liver allotransplantation since it reduces the activities of LTB4 which augments immune responses, and also because it indirectly increases the PGE2 level.

Alanine Transaminase↗
PubMed1996

Inhibition of 5-lipoxygenase promotes the regeneration of the liver after partial hepatectomy in normal and icteric rats.

The role of leukotriene (LT) on liver regeneration after hepatectomy is still unknown. LTB4 stagnates in the liver with obstructive jaundice, because LTB4 is excreted in the bile; therefore, LTB4 may have an effect on liver regeneration after hepatectomy with obstructive jaundice. Release of obstructive jaundice and simultaneous 70% hepatectomy was performed in rats to study the effect of 5-lipoxygenase inhibitor (AA-861) on liver regeneration. Group 1 underwent hepatectomy with administration of 0.1 mL dimethyl sulfoxide (DMSO), group 2 underwent hepatectomy with administration of AA-861 (20 mg/kg/d) dissolved in 0.1 mL DMSO, group 3 underwent hepatectomy with administration of AA-861 (40 mg/kg/d) dissolved in 0.1 mL DMSO, group 4 underwent release of obstructive jaundice and hepatectomy with administration of 0.1 mL DMSO, and group 5 underwent relief of obstructive jaundice and hepatectomy with administration of AA-861 (20 mg/kg/d). DMSO or AA-861 was administered 24 hours before, during, and 24 hours after hepatectomy in each group. Whole blood LTB4 and serum alanine aminotransferase (ALT), total bilirubin, and bromodeoxyuridine labeling index (LI) were measured before and after hepatectomy. The LTB4 level increased during obstructive jaundice and after hepatectomy. LTB4 and serum ALT levels were significantly lower after hepatectomy in the rats that were administered AA-861, and a significantly higher LI was observed at 24 hours after hepatectomy in rats receiving AA-861. Inhibition of 5-lipoxygenase promotes liver regeneration and decreases hepatocyte injury after hepatectomy associated with obstructive jaundice.

Alanine Transaminase↗
PubMed1996

[Phase II study of paclitaxel (BMS-181339) in patients with ovarian cancer by 3-hour intravenous infusion].

A phase II study of Paclitaxel in patients with ovarian cancer by 3-hour intravenous infusion was undertaken by a cooperative study group of 30 institutes. Of 66 cases enrolled, 57 cases were evaluable for efficacy, and 63 cases were evaluable for safety. In spite of the fact that all cases for efficacy evaluation were previously treated with chemotherapy including platinum-based drugs, 2 cases of complete response (CR) and 15 cases of partial response (PR) were observed, with a response rate of 29.8% (The 95% confidence interval of response rate was 18.4-43.4%). Paclitaxel also showed 28.2% (11/39) response rate in patients refractory to treatment by platinum-based drugs. Histologically, the response rates were 28.9% (11/38) in serous adenocarcinoma, 40.0% (2/5) in clear cell adenocarcinoma and 25.0% (1/4) in mucinous adenocarcinoma. As the major laboratory abnormalities, leukopenia, neutropenia and decrease in hemoglobin were observed with incidence rates of 98.4% (62/63), 95.2% (59/62) and 85.7% (54/63), respectively. However, these abnormalities were clinically manageable by either withdrawal of medication, administration of antibiotics, G-CSF or metachysis etc. In addition, thrombocytopenia, elevation in GOT and GPT were seen with moderate incidence. Peripheral neuropathy was a major adverse symptom with an incidence of 79.4% (50/63), followed by alopecia, myalgia, arthralgia and fever. However, the majority of these adverse reactions were less than grade 3. From these findings, we confirmed that 3-hour intravenous infusion of Paclitaxel was a clinically useful chemotherapeutic agent in patients with ovarian cancer.

Adult↗
PubMed1996

[Differentiation of antinociceptive effects of mu, delta and kappa agonists using heat, chemical and mechanical nociception].

The antinociceptive properties of mu (D-Ala2, N-Me-Phe4, Gly5-ol, enkephalin, DAGO), delta (D-Ala2, D-leu5, enkephalin, DADL) and kappa (dynorphin, DYN) were assessed using hot plate (heat), acetic acid-induced writhing (chemical) and tail pinch (mechanical) assays in mice. Test drug and control treatments were given by cisternal injection in a dose volume of 10 microliters.mouse-1. DAGO and DADL produced steep dose-response lines in all the tests. DYN did not produce a consistent antinociceptive effect on the tail pinch test. Utilizing these three different types of assays, the rank order of antinociceptive potency for these three opioids was DAGO > DADL > DYN. The responses to the hot plate and writhing assays were completely inhibited by the same dose of DAGO. DADL displayed equal antinociceptive effects in the hot plate and writhing tests. In the tail pinch assay, however, antinociceptive potency of DAGO was 1/3 less than in other two assays, and DADL was also 1/10 less than in the others. The rank order of antinociceptive potency for DYN in different noxia was the writhing > hot plate >> tail pinch. It was concluded that there are differences in the potency of mu-, delta- and kappa-agonists even when the intensities of chemical and heat noxia are equal. It was also proposed that antinociceptive potencies against mechanical noxia is greatly different among mu-, delta- and kappa-agonists.

Acetic Acid↗
PubMed1996

[Evaluation of hemodynamics of pelvic veins in pregnant women by the ultrasonic pulsed doppler flow velocity analysis].

By means of pulsed Doppler ultrasound, external iliac vein (EIV) velocimetries were carried out on non-pregnant, pregnant and postpartum women. 1. According to the results of a phantom simulation study, the difference between measured values and theoretical values increased when the angle of incidence was over 50 degrees. 2. The coefficient variation of the measured value for ten pregnant women was 4.4 to 9.8%. 3. EIV velocity was 21.4 +/- 7.7cm/sec for non-pregnant women, 20.8 +/- 9.5cm/sec in the 1st trimester, showing no significant difference between the two groups. In the 2nd trimester, it was 8.8 +/- 5.6cm/sec decreasing slightly (p < .001), and 6.1 +/- 3.3cm/sec in the 3rd trimester showing a further decrease (p < 0.01). At 24 hours postpartum, it was 12.7 +/- 4.3cm/sec, an increase over the 3rd trimester (p < 0.001), but it was lower than in non-pregnant women (p < 0.001). At 4 weeks postpartum, it was 19.3 +/- 5.3cm/sec, showing no significant difference from non-pregnant women. The results suggested the following. 1. EIV velocimetry by pulsed Doppler ultrasound is reliable for clinical studies. 2. EIV velocity decreased significantly in the 2nd and 3rd trimesters and recovered to the same level as non-pregnant women by 4 weeks postpartum.

Adult↗
PubMed1996

[A case of advanced gastric cancer showing complete disappearance of cancer cells in multiple liver metastases due to low-dose PMUE therapy].

A case of gastric cancer with liver metastasis who responded well to low-dose PMUE (CDDP, MMC, UFT, etoposide) therapy is reported. A 65-year-old man underwent distal partial gastrectomy with D2 lymph node dissection under the diagnosis of type 5 gastric cancer with multiple liver metastases. Pathological findings revealed papillary adenocarcinoma in the primary lesion and metastatic lymph nodes (No. 8a). Low-dose PMUE therapy after resection of primary lesion was effective for the liver metastases. Exacerbation was suspected, so the lesions of metastases were resected again after 2 years and 11 months postoperative course. All 4 resected lesions of metastases became old fibrous tissue with hyalinization, and 2 of 4 lesions were necrotic and surrounded by fibrous connective tissue. None of these 4 lesions included viable cancer cells. The patient has now been followed with no evidence of exacerbation. It was suggested that low-dose PMUE therapy was effective for liver metastasis of gastric cancer, especially the differentiated type.

Adenocarcinoma, Papillary↗
PubMed1996

[Early cancer in the uterus and ovaries].

Concept of early cancer in gynecology is not well established to date because of the wide variation in biological behaviors of gynecologic tumors. The "early cancer" should be basically diagnosed on the concept that the tumor should be curable, that means a tumor of which growth is limited to the original portion of the organ, i.e. uterine cervix, uterine corps and ovaries, and also no lymph node metastasis could be estimated. The concepts, diagnostic modalities and management strategies of early cancer in uterine cervix, uterine corps and ovaries are discussed.

Female↗