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Biomedical subjects

M Ogata

Publications and source records attributed to M Ogata.

At least 145 records · Page 8Linked to original sources
PubMed1996

[New method for automatic tracking of the endocardial boundary in clinical use].

This study attempted to detect the left ventricular endocardial boundary in six healthy men (volunteers) using a newly developed computerized two-dimensional echocardiography method. Automatic detection of the left ventricular endocardium was achieved by; sampling of pictures, noise reduction of the pictures, filtering, decision of the early loop, detection of the left ventricular endocardial boundary, smoothing the boundary, and correction of the boundary. This process requires only 2-3 sec. Areas of the short-axis cross-sections in systolic and diastolic phases of one cardiac cycle were obtained and the percent change rate of these areas on a cardiac cycle were calculated. These were compared with the results obtained by the manual method. The boundary of the left ventricular endocardium detected by the computerized method almost coincided with that found by the manual method. Areas and the change rates obtained were correlated with those by the manual method (areas: r = 0.86, % change rate of area: r = 0.94). This new method is suitable for clinical use.

Adult↗
PubMed1996

[Acute lymphoblastic leukemia with marked morphologic abnormalities after chemotherapy for gastric cancer].

A 76-year-old man was admitted to our hospital in February, 1994 because of fever and general fatigue. The patient had received radical gastrectomy for gastric cancer in August, 1987 and was subsequently treated with adjuvant chemotherapy using UFT for 25 months. On admission, the leukocyte count was 57,700/microliters with 74% blasts. Bone marrow aspiration revealed proliferation of blasts with marked giant cells and polynucleolar cells. The diagnosis of T-lineage of acute lymphoblastic leukemia (ALL) was then made by analysis of surface markers and T-cell receptor rearrangement. Although combination chemotherapy was initially effective, blasts rapidly reappeared in the peripheral blood, and the patient died of pneumonia in August, 1994. In the presented case, blasts showed marked morphologic abnormalities. It is well known that most cases of therapy-related leukemia deviate from the myeloid lineage, and rarely from the lymphoid lineage. In addition, morphologic abnormalities are rare in de novo ALL. Since such abnormalities were demonstrated in our patient, and UFT was administered for a long period, it is possible that this leukemia occurred as a second malignancy related to UFT treatment.

Aged↗
PubMed1996

[Effects of intravitreal levofloxacin on the rabbit retina].

Effects of intravitreal injection of levofloxacin (LVFX) on the electroretinogram (ERG), visual evoked potential (VEP), and retinal histology were studied in 23 albino and 23 pigmented rabbits to establish the non-toxic intravitreal dosage of LVFX. Doses of 200, 500, 1,000 or 2,000 micrograms of LVFX were injected intravitreally. The ERG and VEP were recorded before injection, and 3 hours, 2 days, 1 week, 2 weeks and 4 weeks after injection. The oscillatory potential transiently deteriorated with 1,000 and 2,000 micrograms doses of LVFX in albino and pigmented rabbits. No ERG changes were observed with 200 and 500 micrograms doses. No abnormal changes were observed in the VEP or retinal histology with any doses of LVFX. These results indicate that intravitreal injections of 200 and 500 micrograms of LVFX are nontoxic to the rabbit retina.

Animals↗
PubMed1996

Possibility of 5-HT3 receptor involvement in alcohol dependence: a microdialysis study of nucleus accumbens dopamine and serotonin release in rats with chronic alcohol consumption.

The present study was performed to examine the involvement of serotonin-3 (5-HT3) receptors in the rat nucleus accumbens (ACC) in alcohol dependence. In alcohol-treated rats, perfusion of 40 mM K+ and 100 mM ethanol (EtOH) through the microdialysis probe increased the extracellular levels of ACC dopamine (DA), compared with controls. Perfusion of the serotonin (5-HT) uptake inhibitor sertlarine enhanced the extracellular levels of ACC 5-HT in both groups. Increased 5-HT availability in the synaptic clefts on the ACC further activated ACC DA release in the alcohol-treated rats, in comparison with controls. In the final experiments, perfusion of the 5.0 microM 5-HT3 receptor agonist 2-methyl-5-HT (2-Me-5-HT) through the microdialysis probe enhanced the extracellular levels of ACC DA. Magnitude of 2-Me-5-HT-induced DA release was significantly higher in alcohol-treated rats than in controls. On the other hand, 40 mM K(+)- and 100 mM EtOH-induced extracellular 5-HT release in alcohol-treated rats were markedly inhibited. These results show that (1) chronic alcohol intake increases the sensitivity of 5-HT3 receptors, (2) 5-HT3 receptors regulate DA release in the ACC, (3) the dopaminergic neuronal systems associated with 5-HT3 ionophore in the ACC were upregulated after chronic alcohol exposure, and (4) chronic alcohol intake desensitizes the serotonergic neuronal systems in rat ACC. These findings suggest that neurochemical functions of 5-HT3 receptors in regulating DA release in the ACC after alcohol exposure compensate for the dysfunction of serotonergic activity to restore the original properties in processing alcohol tolerance and that the development of alcohol dependence may be mediated by ACC 5-HT3 receptors.

Alcoholism↗
PubMed1995

Modulation of TCR-mediated signaling pathway by thymic shared antigen-1 (TSA-1)/stem cell antigen-2 (Sca-2).

Thymic shared antigen-1 (TSA-1) is a glycosyl-phosphatidylinositol (GPI)-anchored differentiation Ag expressed on murine lymphocytes, and is identical to stem cell Ag-2 (Sca-2). Using newly established mAb against TSA-1/Sca-2, we have previously shown that surface TSA-1 expression is induced upon activation in T cells, and that anti-TSA-1 inhibits IL-2 production induced by anti-CD3 stimulation in T cell hybridomas. In the present study, we have analyzed the functional role of TSA-1 during T cell activation using normal T cells, T cell hybridomas, and transfected Jurkat cell lines that expressed either GPI-anchored or transmembrane form of TSA-1. Anti-TSA-1 inhibited IL-2 production from normal T cells stimulated with soluble anti-CD3 plus accessory cells. Anti-TSA-1 exhibited the inhibitory effect on T cells, but not on accessory cells, because anti-TSA-1 inhibited IL-2 production in Jurkat cells transfected with TSA-1 cDNA, but not in control transfectant. A transmembrane form of TSA-1 was expressed in Jurkat cells by fusing the extracellular portion of TSA-1 to the transmembrane and cytoplasmic regions of the class 1 Db. The analysis using this transfectant revealed that anti-TSA-1-mediated inhibition of IL-2 production did not require the GPI anchor of TSA-1. Finally, in addition to the inhibition of IL-2 production, tyrosine phosphorylation of CD3 zeta-chains observed following TCR stimulation, one of the important early activation events, was markedly reduced by anti-TSA-1. These results imply that TSA-1/Sca-2 plays an important regulatory role in the TCR signaling pathway of activated T cells in addition to its role in T cell differentiation.

Animals↗
PubMed1995

Identification of an I kappa B alpha-associated protein kinase in a human monocytic cell line and determination of its phosphorylation sites on I kappa B alpha.

Nuclear factor kappa B (NF-kappa B) is stored in the cytoplasm as an inactive form through interaction with I kappa B. Stimulation of cells leads to a rapid phosphorylation of I kappa B alpha, which is presumed to be important for the subsequent degradation. We have recently reported the establishment of a lipopolysaccharide (LPS)-dependent cell-free activation system of NF-kappa B in association with the induction of I kappa B alpha phosphorylation. In this study, we have identified a kinase in cell extracts from the LPS-stimulated human monocytic cell line, THP-1, that specifically binds and phosphorylates I kappa B alpha. LPS stimulation transiently enhanced the I kappa B alpha-bound kinase activity in THP-1 cells. Mutational analyses of I kappa B alpha and competition experiments with the synthetic peptides identified major phosphorylation sites by the bound kinase as Ser and Thr residues in the C-terminal acidic domain of I kappa B alpha. Moreover, we show that the peptide, corresponding to the C-terminal acidic domain of I kappa B alpha, blocked the LPS-induced NF-kappa B activation as well as inducible phosphorylation of endogenous I kappa B alpha in a cell-free system using THP-1 cells. These results suggested that the bound kinase is involved in the signaling pathway of LPS by inducing the phosphorylation of the C-terminal region of I kappa B alpha and subsequent dissociation of the NF-kappa B.I kappa B alpha complex.

Amino Acid Sequence↗
PubMed1995

RP105, a novel B cell surface molecule implicated in B cell activation, is a member of the leucine-rich repeat protein family.

The RP105 Ag is a murine B cell surface molecule that transmits an activation signal into B cells following ligation with anti-RP105 mAb. The activation leads to protection of B cells from irradiation- or dexamethasone-induced apoptosis, and to B cell proliferation. A cDNA encoding the RP105 Ag was isolated. An encoded protein is a type I transmembrane protein consisting of 641 amino acids in a mature form. Northern hybridization with a probe specific for the cDNA clone detected a transcript with a size of approximately 3 kb. The transcript was observed in spleen, but not in thymus, kidney, muscle, heart, brain, or liver. Stable transfection of the cDNA clone conferred the expression of the RP105 Ag on a pro-B cell line, which was confirmed by immunofluorescence staining and immunoprecipitation with anti-RP105 mAb. The RP105 molecule possesses 22 tandem repeats of a leucine-rich motif. These repeated motifs are observed in members of the leucine-rich repeat protein family, and have been implicated in protein-protein interactions, such as cell adhesion or receptor-ligand binding. Amino- and carboxyl-flanking regions that are characteristically conserved among members of the family are located on both sides of tandemly repeated leucine-rich motifs in RP105 molecule. These results demonstrate that RP105 is a novel member of the leucine-rich repeat protein family, and the first member that is specifically expressed on B cells.

Amino Acid Sequence↗
PubMed1995

Adenosine kinase-deficient mutant of Saccharomyces cerevisiae.

A cordycepin-resistant mutant strain of Saccharomyces cerevisiae (CD-R2) was found to be deficient in adenosine kinase. This mutant accumulated S-adenosylhomocysteine during growth in the presence of exogenous adenosine and it grew in a pseudohyphal manner in the presence of this nucleotide.

Adenosine↗
PubMed1995

cDNA cloning and characterization of a novel receptor-type protein tyrosine phosphatase expressed predominantly in the brain.

Protein tyrosine phosphatase has the potential to control various cellular events by negatively regulating the extent of tyrosine phosphorylation. Here, we report the isolation of a murine receptor protein tyrosine phosphatase, PTPBR7, which is expressed almost exclusively in the brain. Though the cytoplasmic portion of PTPBR7 reveals high similarity to HePTP/LC-PTP and STEP, these are, unlike PTPBR7, non-receptor protein tyrosine phosphatases. Unlike most receptor protein tyrosine phosphatases, PTPBR7 has only one cytoplasmic phosphatase domain, and its extracellular domain reveals no obvious structural similarity to known molecules. Thus, PTPBR7 defines a new subfamily of receptor-type protein tyrosine phosphatases. The putative extracellular domain of PTPBR7 was expressed in COS-7 cells as a chimeric fusion protein with an immunoglobulin Fc portion (PTPBR7-Fc). PTPBR7-Fc was secreted in the culture supernatant, confirming the capability of the extracellular domain of PTPBR7 to translocate across the cytoplasmic membrane. The cytoplasmic portion of PTPBR7 was expressed as a fusion protein in bacteria and was demonstrated to have catalytic activity. The expression of PTPBR7 was detectable in brain and especially in cerebellum but undetectable in liver, lung, heart, kidney, thymus, bone marrow, and spleen. In situ hybridization analysis revealed the most prominent signal in Purkinje cells. The predominant expression of PTPBR7 in the brain suggests that PTPBR7 may have role(s) in neuronal cells.

Amino Acid Sequence↗
PubMed1995

NMR spectroscopic characterization of adinazolam mesylate: pH-dependent structure change in aqueous solution and active methylene.

The present study is to investigate structural changes of adinazolam mesylate in aqueous solution under various pH conditions by NMR spectroscopy. By plotting of the signal integration and chemical shifts of the side chain, pKa values for imine hydrolysis and the side chain amine were determined. Conformational analysis of the side chain was performed with deuterium-induced isotope effects on chemical shifts, nuclear Overhauser effects, relaxation times, and energy calculations. Hydrogen/deuterium exchange due to an active methylene at the 4-position under basic conditions was revealed.

Antidepressive Agents↗
PubMed1995

Effects of norfloxacin on the retina in rabbits.

BACKGROUND: Fluoroquinolones have a strong affinity with melanin, and their ocular effects have been reevaluated. Norfloxacin, one of the fluoroquinolones, has broad-spectrum activity against aerobic gram-positive and gram-negative bacteria. We examined the retinal toxicity and intraocular pharmacokinetics of intravitreal norfloxacin in rabbits. METHODS: Twenty-three albino and 23 pigmented rabbits were divided into three groups to evaluate retinal toxicity and two groups to investigate the intraocular pharmacokinetics. Each of these five groups was further divided into two subgroups (albino rabbits and pigmented rabbits). RESULTS: With 500 micrograms norfloxacin, the oscillatory potential of the electroretinogram was transiently and selectively deteriorated in albino and pigmented rabbits, whereas the electroretinogram remained unchanged with 50 micrograms in pigmented rabbits. No changes were observed in the visual evoked potential or on histology of the retina 7 days after an intravitreal injection of 50 or 500 micrograms norfloxacin. The electroretinogram and the retinal histology became abnormal 7 days after four intravitreal injections of 500 micrograms norfloxacin at 7-day intervals. As regards the intraocular pharmacokinetics after an intravitreal injection, the norfloxacin concentration in the chorioretina was as high as that in the vitreous 3 h after injection and was much higher than that in the vitreous 7 days after injection. Similar results were obtained after multiple injections. CONCLUSIONS: These results indicate a high concentration of norfloxacin in the melanin-containing ocular tissues.

Animals↗
PubMed1995

A simple and rapid method for preliminary evaluation of in vivo efficacy of anti-HIV compounds in mice.

In vivo efficacy of anti-HIV compounds is affected by various factors such as bioavailability, metabolism, clearance, and toxicity. Here we report a simple and rapid method that might be useful for preliminary evaluation of in vivo efficacy of anti-HIV compounds. MT-4 cells carrying proviral HTLV-1 were infected with HIV-1 in vitro and injected into the peritoneal cavity of SCID mice or BALB/c mice. Inoculated cells survive for 1-2 days, and support one to two cycles of viral replication which can be monitored by RT activity or p24 content in the supernatants of peritoneal wash fluids. Test compounds were administered either orally or subcutaneously. AZT, DDC and DDI, the nucleoside-type RT inhibitors currently in clinical use, all showed potent anti-HIV-1 activities in this mouse/MT-4 assay. HEPT (E-EBUdM), a non-nucleoside RT inhibitor, also showed potent anti-HIV-1 activity in vivo, whereas TIBO (R82913), another non-nucleoside RT inhibitor, was less active. In protease inhibitors KNI-272 and Ro 31-8959 showed good in vivo activities, while KNI-144, a compound closely related to KNI-272, showed poor in vivo activity. This mouse/MT-4 assay, although having a number of shortcomings as an animal model for HIV-1 infection, may be of some practical utility for preliminary evaluation of in vivo efficacy of potential anti-HIV compounds.

Animals↗
PubMed1995

Laparoscopy-guided extracorporeal resection of early gastric carcinoma.

BACKGROUND AND STUDY AIMS: Though endoscopic mucosal resection is successful for early gastric carcinoma, the indication for endoscopic mucosal resection appears to exclude larger early gastric carcinomas. We report here on our experience in resecting early gastric carcinoma using laparoscopy-guided partial resection of the stomach extracorporeally. PATIENTS AND METHODS: Seven patients with early gastric carcinoma were treated surgically under laparoscopic guidance. After an inspection of the abdominal cavity by laparoscope through an umbilical port, a gastrofiberscope was then inserted into the stomach perorally, and confirmation of the site of the carcinoma was provided by illuminating the interior gastric wall endoscopically. The gastric wall portion including the carcinoma was then exteriorized through a small upper midline incision, and resected. The gastrotomy was sutured extracorporeally, and then repositioned inside the abdomen. RESULTS: All the carcinomas were successfully resected extracorporeally, with cancer-free margins. Postoperative courses were uneventful, and the average period of hospitalization after the operation was ten days. CONCLUSIONS: This type of laparoscopy-guided partial resection of the stomach is expected to become more widely adopted as a treatment for early gastric carcinoma.

Adenocarcinoma↗
PubMed1995

An isolated perforation of the jejunum caused by child abuse. A case report.

Presented is the case of a 10-month-old boy who died of general peritonitis due to an isolated perforation of the proximal jejunum. The autopsy findings included multiple bruises and abrasions inflicted at different times, probable bite marks, an old cerebral contusion tear, malnutrition, and an involution of the thymus, this evidence cumulatively suggesting that the decedent was a battered child. The abdomen showed a general peritonitis, and the wall of the jejunum was ruptured on the antimesenteric surface, 2 cm from the duodenojejunal junction (the ligament of Treitz). Microscopically, the ruptured area showed a linear rent in the mucosa and muscularis, and the narrow necrotic lesion was surrounded by normal-appearing bowel tissue. Therefore, it appeared that an external force had compressed the jejunum against the spine, thus rupturing the jejunum near the duodenojejunal junction, a point of fixation.

Child Abuse↗
PubMed1995

Prospective analysis of a rapid trauma ultrasound examination performed by emergency physicians.

The objective of this prospective study was to determine the sensitivity, specificity, and accuracy of the rapid trauma ultrasound examination, performed by emergency physicians, for detecting free peritoneal and thoracic fluid in patients presenting to a level I trauma center with major blunt or penetrating torso trauma. Emergency medicine residents and faculty were trained to perform an ultrasound examination of the torso evaluating for free intraperitoneal, retroperitoneal, pleural, and pericardial fluid. In the 245 study patients, emergency physicians examined 975 intracavitary spaces and demonstrated 64 positive findings for free fluid as documented by computed tomography scan, diagnostic peritoneal lavage, exploratory laparotomy, chest radiography, tube thoracostomy, or formal two-dimensional echocardiography. The rapid trauma ultrasound examination was 90% sensitive, 99% specific, and 99% accurate. Ultrasonography can serve as an accurate diagnostic adjunct in detecting free peritoneal and thoracic fluid in trauma patients. Appropriately trained emergency physicians can accurately perform and interpret these trauma ultrasound examinations.

Abdominal Injuries↗
PubMed1995

Teleology of motion sickness.

We investigated motion sickness evoked by walking while wearing horizontally reversing goggles. The subjects were 36 healthy adults and 90 children aged 4 to 15 years. Most adults soon displayed not only severe sickness, but also dizziness and instability. Instability was certified by Graybiel's ataxia tests in 10 adults. Young children aged 4 to 5 years rarely became sick; however, they showed marked ataxia manifested as drunken gait, falling, or failure to stand up. In older children, autonomic nervous symptoms became manifest and more severe, but ataxia became less severe since locomotion was stopped by uncomfortable symptoms. The present study strongly suggests that motion sickness makes animals learn loss of spatial orientation, which inevitably produces loss of balance.

Adolescent↗
PubMed1995

[A surviving case of disseminated tuberculosis complicated with severe respiratory failure, pancytopenia, DIC, drug induced fever and pneumothorax in an elderly patient].

We reported a survival case of a 78-year-old female with disseminated tuberculosis complicated with severe respiratory failure, pancytopenia, DIC, drug induced fever and pneumothorax. Atypical symptoms and presence of chronic illness make the early diagnosis of disseminated tuberculosis in the elderly difficult. In this report, we emphasized that both a high awareness of possible clinical diagnoses and the performance of some clinical procedures including bronchoalveolar lavage were useful. Disseminated tuberculosis in the elderly with multiple complications which is rare condition, was discussed.

Aged↗