Biomedical subjects

M Morimoto

Publications and source records attributed to M Morimoto.

At least 91 records · Page 5Linked to original sources

PubMed1998

Overview and initial results of the very long baseline interferometry space observatory programme

High angular resolution images of extragalactic radio sources are being made with the Highly Advanced Laboratory for Communications and Astronomy (HALCA) satellite and ground-based radio telescopes as part of the Very Long Baseline Interferometry (VLBI) Space Observatory Programme (VSOP). VSOP observations at 1.6 and 5 gigahertz of the milli-arc-second-scale structure of radio quasars enable the quasar core size and the corresponding brightness temperature to be determined, and they enable the motions of jet components that are close to the core to be studied. Here, VSOP images of the gamma-ray source 1156+295, the quasar 1548+056, the ultraluminous quasar 0014+813, and the superluminal quasar 0212+735 are presented and discussed.

Journal Article↗

PubMed1998

How to treat dural arteriovenous malformations or fistulas

The clinical symptoms of intracranial dural arteriovenous fistulas (AVFs) depend mainly on the site and venous drainage pattern of the lesion. The goal of treatment of the lesion is the permanent and complete elimination of the arteriovenous shunt. Transarterial embolization or stereotactic radiation may affect feeding arteries or nidus. The involved sinus can be obliterated by percutaneous or surgical transvenous embolization, or resected by surgery. In cases of patients with pure leptomeningeal drainage, surgical interruption of leptomeningeal drainage may be effective. Based on the experiences reported in the literature, transarterial embolization of accessible feeding arteries is the initial treatment to decrease arterial blood flow. Transvenous embolization may be effective depending on the venous drainage pattern. For the AVFs remaining after transarterial embolization, stereotactic radiosurgery is recommended if feasible. Transvenous embolization may be applied cautiously considering the risk of venous hypertension and intracranial hemorrhage. Direct microsurgery is indicated if stereotactic radiosurgery is not performed safely. For cases without dural sinus drainage, surgical interruption of leptomeningeal drainage may be applied safely. The decision to intervene in dural AVFs is based on the following factors: age and general condition of the patient, severity of the presenting symptoms, natural history of the lesion if left untreated, angiographic features on the location of dural AVFs and the venous drainage pattern, and morbidity and mortality of the procedure being considered.

Journal Article↗

PubMed1998

Lactic dehydrogenase virus infection enhances parasite egg production and inhibits eosinophil and mast cell responses in mice infected with the nematode Nippostrongylus brasiliensis.

The effects of lactic dehydrogenase virus (LDV) infection on the protective immune responses to the nematode Nippostrongylus brasiliensis were studied. Mice with chronic LDV infection showed significantly higher levels of parasite egg production than non-LDV-infected (control) mice after N. brasiliensis infection. Concurrent LDV infection also suppressed peripheral blood eosinophilia and the lung mastocytosis induced by this nematode. LDV infection showed higher expression levels of the interferon-gamma (IFN-gamma) mRNA in lymph nodes compared with control mice before N. brasiliensis infection. In addition, the IgG2a production in LDV-infected mice was higher than that in control mice before and after N. brasiliensis infection. These results suggest that LDV infection modulates protective immune responses against N. brasiliensis infection by the activation of T-helper type 1 cells.

Animals↗

PubMed1998

Interferon-gamma plays a role in pancreatic islet-cell destruction of reovirus type 2-induced diabetes-like syndrome in DBA/1 suckling mice.

Reovirus type 2 (Reo-2) infection in DBA/1 suckling mice causes insulitis, which leads to pancreatic islet-cell destruction, resulting in a diabetes-like syndrome. T-helper (Th) 1 cytokines are thought to play a key role in islet inflammation in insulin-dependent diabetes mellitus. We examined this hypothesis in the Reo-2-induced diabetes-like syndrome. We used reverse transcriptase polymerase chain reaction (PCR) and quantitative PCR techniques to examine mRNA expression of interferon (IFN)-gamma (Th1 type cytokine), and interleukin (IL)-4 (Th2 type cytokine) in splenic cells. We observed that in Reo-2 infected mice the level of IFN-gamma expression increases with the development of insulitis, whereas expression of message for IL-4 is minimal to detectable with the immuno-inflammatory process 10 days after infection. The treatment of monoclonal antibody (mAb) against mouse IFN-gamma during the expansion phase of insulitis (5-9 days after infection) inhibited the development of insulitis and the elevation of blood glucose concentrations in a dose dependent manner. Furthermore altered CD4+/CD8+ cell ratio compared with uninfected mice in the splenic cells by the infection was recovered to the ratio of uninfected mice by the treatment of mAb against mouse IFN-gamma, suggesting normalization of T cell balance in immune system. These results suggest that Reo-2-triggered autoimmune insulitis may be mediated by Th1 lymphocytes and IFN-gamma may play a role in islet inflammation leading to islet cell destruction.

Animals↗

PubMed1998

Expression of interferon receptor genes (IFNAR1 and IFNAR2 mRNA) in the liver may predict outcome after interferon therapy in patients with chronic genotype 2a or 2b hepatitis C virus infection.

Hepatitis C virus (HCV) genotype 2a or 2b is associated with a favorable outcome after interferon therapy. However, 19% to 33% of patients do not respond to therapy. We investigated whether interferon receptor gene (IFNAR1 and IFNAR2 mRNA) expression in the liver before interferon therapy predicts long-term response to therapy in patients with genotype 2a or 2b HCV infection. Twenty-seven patients who subsequently received interferon-alpha therapy underwent liver biopsies before interferon therapy. Hepatic IFNAR1 and IFNAR2 mRNA were determined using a reverse transcription-polymerase chain reaction assay. Twenty (74%) patients responded to interferon therapy, while the remaining seven (26%) patients were nonresponders. The expression rates of IFNAR1 and IFNAR2 mRNA in the liver were significantly higher in responders than nonresponders (p < 0.01, by chi-square test). The presence of either IFNAR1 or IFNAR2 mRNA predicted complete response to interferon treatment, with a positive predictive value of 100%. Multiple logistic regression analysis showed that IFNAR1 and/or IFNAR2 mRNA expression was the only significant predictor of the effectiveness of IFN therapy (p = 0.0002). We conclude that expression of interferon receptor genes in the liver is a useful index for predicting the long-term efficacy of interferon therapy in patients with chronic genotype 2a or 2b HCV infection.

Adult↗

PubMed1998

[A case of a urachal sinus with umbilical infection].

A case of the urachal sinus accompanied by umbilical infection is reported. A 21-day-old female infant was seen at the hospital because of umbilical granuloma, redness and umbilical purulent discharge. The separation of the umbilical cord in her neonate was delayed. IVP and CT examination revealed a urachal diverticulum from the urinary bladder to the umbilicus. The patient was diagnosed to have internal and external urachal sinus. In spite of systemic administration of antibiotic agents, the umbilical infection did not get well. After extruding of the external urachal sinus from the umbilicus, she had not had any symptoms. After 3 months the IVP did not revealed in urachal diverticulum.

Female↗

PubMed1998

Polysaccharides from Agaricus blazei stimulate lymphocyte T-cell subsets in mice.

Subset analysis of splenic lymphocytes using flow cytometry showed that the percentages of Thy1.2-(pan T-cells), L3T4-(CD4, helper T-cells), and Lyt2-(CD8, cytotoxic T-cells) positive cell populations were significantly increased in mice orally administered a hot water-soluble fraction from Agaricus blazei as compared with mice treated only with saline. 13C-NMR data indicates that the main component in the active polysaccharide is the complex of alpha-1,6- and alpha-1,4-glucan, which had already been shown to have anti-tumor activity against Sarcoma 180. It seems that the polysaccharide from Agaricus blazei may be an effective prophylactic, protecting humans against cancer by stimulating lymphocytes such as cytotoxic T-cells.

Adjuvants, Immunologic↗

PubMed1998

Macroscopic distribution of coronary atherosclerotic lesions in cholesterol-fed rabbits.

In the present study we macroscopically examined a change in the distribution of coronary atherosclerosis in cholesterol-fed rabbits. Rabbits were fed a cholesterol-enriched diet for 15 weeks, then replaced by a normal diet, and were sacrificed at 15, 24, 32 and 42 weeks after the start of the experiment. The coronary atherosclerosis in the cholesterol-fed rabbits was distributed more densely in the proximal portion than in the middle and distal portions, and the lesions were severe at 24 and 32 weeks after the start of the experiment. comparison of lesions in the three portions at these time points showed that the percentages of lesion areas in the proximal portion, the middle portion and the distal portion were approximately 51%, 21 to 25% and 0.2 to 3.7%, respectively. Macroscopic observation of the coronary atherosclerotic lesions showed that the lesions formed over the vessel lumen in the proximal portion within the range of approximately 5 mm from the orifice of the left coronary artery. In the middle portion, the lesions formed predominantly around the orifices of branches as small patchy lesions from 1 to 3 mm in diameter. These findings support previous histopathological reports that suggested that the incidence of stenosis in the proximal portion was high, and the incidence of lesion occurrence in the middle and the distal portions varied. The method, macroscopical investigation of the coronary artery, is useful for analyzing coronary atherosclerosis in the rabbit.

Animals↗

PubMed1998

Elastic properties of living fibroblasts as imaged using force modulation mode in atomic force microscopy.

Using the force modulation mode in atomic force microscopy, we measured elastic properties of living mouse fibroblasts (NIH3T3) in a culture medium. The topographic images of the cellular surface and the corresponding elastic images of the cellular surface were able to be captured simultaneously with high spatial resolution. The consecutive images were useful for examining time-dependent changes in the cellular surface. We observed that some cells continued to shrink and change their softness for 2 hours. Then the force modulation mode in atomic force microscopy shows potential use in analyzing time-dependent regional elastic properties of living cells with high spatial resolution.

3T3 Cells↗

PubMed1998

Evaluation of organic solvent-induced inflammation modulated by neuropeptides in the abdominal skin of hairless rats.

In this study, the severity and time course of inflammation induced by 4 organic solvents (acetone, cyclohexane, toluene and m-xylene), and the effect of neuropeptides during the inflammation were investigated in the hairless rat abdominal skin. Plasma extravasation used as a parameter of inflammation was measured by Evans blue and 125I-bovine serum albumin (BSA). Total volume of plasma extravasation induced by 4 organic solvents in 240-min exposure was as follows: toluene > m-xylene > cyclohexane > acetone = 0. While hydrophobic solvents (toluene, m-xylene, cyclohexane) induced plasma extravasation, the hydrophilic solvent, acetone, did not induce plasma extravasation. It was suggested that the severity and time course of plasma extravasation depend on chemical characteristics of the organic solvents. In immunohistochemical study, substance P (SP)-immunoreactive nerve fibers (IRNF) and calcitonin gene-related peptide (CGRP)-IRNF were intact during 240-min exposure to acetone. In contrast, cyclohexane, toluene, and m-xylene reduced the number of SP-IRNF and CGRP-IRNF in 10 min exposure and further reduced immunoreactivity. In hairless rats treated with systemic capsaicin, the above plasma extravasation was significantly reduced, along with SP-IRNF and CGRP-IRNF; however, protein gene product 9.5 (PGP 9.5)-IRNF was nearly intact. These results indicated that certain organic solvents induce instance of inflammation that vary widely in terms of their severity and time course, and that these differences are correlated with neuropeptides.

Abdomen↗

PubMed1998

Effect of MDR antagonists on the cidal activity of vincristine for cells expressing MDR-1 is superior to those expressing MRP.

In an attempt to identify the target protein, P-GP or mrp, of each MDR antagonist, verapamyl (Ver), dipyridamole (Dip), or cyclosporin A (Cy-A), this study was designed to compare the activity of the three afore-mentioned drugs and to test their combined effect on the cidal activity of vincristine (VCR) in five types of wild and the corresponding VCR-resistant cultured cell lines from human leukemia and lymphoma. Three of the VCR-resistant cell lines are characterized by the overexpression of mdr-1, while two cell lines overexpress mrp. We found that all three antagonists additively to synergistically enhanced the cidal activity of VCR for the five wild-type and VCR-resistant cell lines in a dose dependent manner when used singly. Combinations consisting of a 20% inhibitory concentration (IC20) of VCR plus two antagonists also showed additive to synergistic effects on both wild and VCR-resistant cell lines. It is of interest that the combined effect of IC20 VCR plus MDR antagonists on the three VCR-resistant cell lines expressing mdr-1 was significantly superior to those of the two cell lines expressing the mrp gene. These results suggest that the combined effect of MDR antagonists work better than their single use and that the MDR antagonists work more efficiently in cells showing drug resistance through mdr-1 than in those utilizing mrp.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1998

[Subsegmental transcatheter hepatic arterial embolization under balloon occlusion of the corresponding hepatic vein with SMANCS].

Recently, subsegmental transcatheter hepatic arterial embolization under balloon occlusion of the corresponding hepatic vein has been performed to treat hepatic infarction in subregion hepatocellular carcinoma (HCC). Here, we report subsegmental transcatheter hepatic arterial embolization under balloon occlusion of the corresponding hepatic vein with styrene maleic acid neocarzinostatin lipiodol (SMANCS) (SMANCS-TAE under balloon occlusion of the corresponding hepatic vein). This study included 9 patients with HCC who underwent SMANCS-TAE under balloon occlusion of the corresponding hepatic vein. In all patients, the therapeutic effects (TE) were evaluated according to the criteria of direct response to liver cancer treatment on abdominal computed tomography (CT) 3 weeks after surgery. In 7 patients who could be followed for more than one year, there was no postoperative relapse at the site of treatment. Furthermore, this procedure facilitated the detection of accumulation of SMANCS not only in the tumor but also in the subregion of the tumor in patients with HCC involving immature arterial tumor neoplastic vessels. In patients with large HCC complicated by severe heart failure showing a poor general condition, this procedure allowed treatment to be completed without complication. SMANCS-TAE under balloon occlusion of the corresponding hepatic vein, which can also embolize the portal vein by applying targeting chemotherapy with SMANCS, may cause necrosis not only in the tumor but also in noncancerous liver tissues. This procedure may be an indication for a larger number of cases than standard TAE, facilitating more complete local treatment.

Antineoplastic Agents↗

PubMed1998

[SMANCS-TAE combined with PEI in the treatment for hepatocellular carcinoma].

From January 1996 to August 1997, 24 patients with advanced hepatocellular carcinoma (HCC) equal to or more than 2 cm (mean +/- SD; 4.1 +/- 3.0 cm) in main tumor diameter were treated by SMANCS-TAE (20 cases) or SMANCS-TAI (4 cases) combined with PEI. Six cases had solitary lesion, 16 cases had multiple lesions, and 2 cases had massive lesions. After this combination therapy, 21 of 24 cases had complete tumor necrosis. During 3 to 19 months follow up period, 12 cases had cancer-free survival (SMANCS-TAI; 3 cases), and 9 cases had tumor recurrences (3 cases were local recurrences and 6 cases involved new lesions). Two cases died of hepatic infarction and cancer death, however, the remaining 22 cases were surviving. SMANCS-TAE combined with PEI is useful treatment for advanced large or multiple HCC lesions in patients who are poor surgical risks.

Aged↗

PubMed1998

Expression of c-kit and stem cell factor mRNA in liver specimens from healthy adult dogs.

OBJECTIVE: To determine expression of c-kit and stem cell factor (SCF) mRNA in liver specimens from healthy adult dogs and to investigate whether differentiation of mast cells in the liver of dogs is supported by the c-kit receptor tyrosine kinase/SCF system. ANIMALS: 3 healthy adult Beagles. PROCEDURE: The nucleic acid sequence of the canine c-kit fragment of the intracellular tyrosine kinase domain was determined. Magnitudes of c-kit and SCF mRNA expression in liver samples was determined by means of northern blot analysis, using probes based on canine sequences. To determine which cells were expressing c-kit and SCF mRNA, in situ hybridization was performed. RESULTS: Expression of c-kit and SCF mRNA in liver samples was weak but appreciable. In situ hybridization revealed that c-kit and SCF mRNA expression was restricted to mast cells and plasma cells, respectively. CONCLUSION: Expression of SCF mRNA was detected in liver from healthy adult dogs. The c-kit receptor tyrosine kinase/SCF system may, possibly in combination with other growth factor and receptor systems, be involved in proliferation and differentiation of liver mast cells in dogs.

Animals↗

PubMed1998

[Pulmonary artery injury caused by mal-manipulation of a pulmonary artery catheter].

A 71-year-old male was scheduled for aortic valve replacement. After tracheal intubation under high-dose fentanyl anesthesia, a pulmonary artery balloon catheter was inserted via the right internal jugular vein. However, after withdrawing the catheter with the balloon inflated, we found abrupt massive bleeding from the endotracheal tube. Fortunately, hemorrhage stopped with PEEP (20-25 cmH2O). Bronchofiberscopy could not detect the bleeding point. Chest X-ray showed the pulmonary artery balloon catheter in the right pulmonary artery and atelectasis of the middle and lower lobes. Five days later, he was extubated without rehemorrhage. Three weeks after hemorrhage, the patient successfully underwent an aortic valve replacement, and was discharged on the 25th post-operative day.

Aged↗

PubMed1998

[Epidural anesthesia for cesarean section in a twin pregnant patient with severe aortic stenosis].

A 35-year-old twin primigravida with aortic stenosis underwent cesarean section under epidural anesthesia. She had her ventricular septal defect repaired at 3 years of age. Preoperative ultrasonic study revealed severe aortic stenosis in which valve area was 0.77 cm2 and pressure gradient between the left ventricle and the aorta was 80 mmHg. We persuaded her and her husband to discontinue pregnancy and recommended aortic valve replacement surgery. They rejected our suggestions, and cesarean section was scheduled at 29 weeks' gestation. We chose epidural anesthesia. A 20-gauge catheter and a pulmonary artery catheter were inserted to monitor the hemodynamics. Two lumbar epidural catheters were placed at the L 1-2 and L 4-5 intervertebral spaces. Sixteen milliliters of 1.5% mepivacaine were injected, producing anesthesia up to T 6 level. The babies were delivered, and postnatal conditions of both infants were satisfactory. Methoxamine 1 mg was administered four times when systolic blood pressure decreased to 80 mmHg following deliveries. Otherwise, peripartal hemodynamics was stable, and she was transferred to the intensive care unit (ICU). Postoperative pain was controlled with epidural infusion of fentanyl. She did not complain of chest pain perioperatively and was discharged from the ICU next day.

Adult↗

PubMed1997

Effect of chronic ethanol feeding on lipid peroxidation and protein oxidation in relation to liver pathology.

Liver lipid peroxidation, nonheme iron, antioxidants, and protein oxidation were investigated in experimental alcohol-induced liver disease in the rat. Wistar male rats were intragastrically and continuously infused for 4 weeks with a high-fat diet plus an ethanol or an isocaloric amount of dextrose, maintaining a high blood alcohol level (200-300 mg%). This model induced fatty liver, spotty necrosis, and focal inflammation. This pathology was associated with an enhanced lipid peroxidation and a decrease in the major antioxidant factors. Hepatic alpha-tocopherol and glutathione concentrations were significantly decreased in ethanol-fed rats. Glutathione peroxidase (GPx) was also decreased, whereas glutathione S-transferase (GST) was unaffected. The nonheme iron level was significantly decreased. Protein oxidation was assessed through three parameters: protein thiols, protein carbonyl groups, and the activity of glutamine synthetase (GS), a centrilobular enzyme particularly susceptible to free-radical-mediated damage. Ethanol-fed rats had decreased protein thiol concentrations and reduced GS activity, together with increased protein carbonyls. A significant correlation between GS activity and the pathological score was observed. This study confirms the ethanol-related increase in lipid peroxidation and shows that ethanol impairs the hepatic antioxidant potential. Furthermore, evidence of oxidative protein damage is given, including decreased activity of a key enzyme of ammonia metabolism. These protein disturbances may contribute to the pathogenesis of the observed liver damage.

Animals↗

PubMed1997

Lipid peroxidation, CYP2E1 and arachidonic acid metabolism in alcoholic liver disease in rats.

The role of cytochrome P450 metabolism of fatty acids and lipid peroxidation in the alterations of the fatty acid composition of the liver and liver pathology was investigated. The CYP2E1 inhibitors partially prevented CYP2E1 induction by ethanol and completely blocked lipid peroxidation. However, the liver pathology induced by ethanol was only partially prevented as was the decrease in arachidonic acid in total liver lipid, triglycerides and cholesterol esters. This means that liver peroxidation induced by ethanol can not completely account for the liver pathology or the decrease in arachidonic acid caused by ethanol. Lauric acid omega-1 hydroxidation by the liver microsomes in vitro was increased by ethanol and partially blocked by CYP2E1 inhibitors. However, although ethanol feeding increased the total hydroxidation and epoxidation of arachidonic acid, these were not inhibited by CYP2E1 inhibitors. Thus the ethanol-induced arachidonic acid depletion is not likely due to CYP2E1 metabolism of arachidonic acid, since the severity of liver pathology correlated negatively with the decrease in arachidonic acid in the ethanol-fed rats. The increase in its metabolism by microsomes and decrease in synthesis may be an important mechanism of ethanol-induced liver injury.

Animals↗