Biomedical subjects

N Kurihara

Publications and source records attributed to N Kurihara.

At least 19 recordsLinked to original sources

PubMed1998

Immortalization of osteoclast precursors by targeting Bcl -XL and Simian virus 40 large T antigen to the osteoclast lineage in transgenic mice.

Cellular and molecular characterization of osteoclasts (OCL) has been extremely difficult since OCL are rare cells, and are difficult to isolate in large numbers. We used the tartrate-resistant acid phosphatase promoter to target the bcl-XL and/or Simian Virus 40 large T antigen (Tag) genes to cells in the OCL lineage in transgenic mice as a means of immortalizing OCL precursors. Immunocytochemical studies confirmed that we had targeted Bcl-XL and/or Tag to OCL, and transformed and mitotic OCL were readily apparent in bones from both Tag and bcl-XL/Tag mice. OCL formation in primary bone marrow cultures from bcl-XL, Tag, or bcl-XL/Tag mice was twofold greater compared with that of nontransgenic littermates. Bone marrow cells from bcl-XL/Tag mice, but not from singly transgenic bcl-XL or Tag mice, have survived in continuous culture for more than a year. These cells form high numbers of bone-resorbing OCL when cultured using standard conditions for inducing OCL formation, with approximately 50% of the mononuclear cells incorporated into OCL. The OCL that form express calcitonin receptors and contract in response to calcitonin. Studies examining the proliferative capacity and the resistance of OCL precursors from these transgenic mice to apoptosis demonstrated that the increased numbers of OCL precursors in marrow from bcl-XL/Tag mice was due to their increased survival rather than an increased proliferative capacity compared with Tag, bcl-XL, or normal mice. Histomorphometric studies of bones from bcl-XL/Tag mice also confirmed that there were increased numbers of OCL precursors (TRAP + mononuclear cells) present in vivo. These data demonstrate that by targeting both bcl-XL and Tag to cells in the OCL lineage, we have immortalized OCL precursors that form bone-resorbing OCL with an efficiency that is 300-500 times greater than that of normal marrow.

Acid Phosphatase↗

PubMed1998

Comparison of ipsilateral activation between right and left handers: a functional MR imaging study.

We used fMRI to compare the ipsilateral activation in the sensorimotor region (SMR) during dominant and non-dominant hand motor tasks between right and left handers. In right handers, the ipsilateral activation was significantly greater during non-dominant (left) hand task than dominant (right) hand task, while in left handers, it showed no significant difference. The ipsilateral activation was most pronounced in the precentral subregion (presumably corresponding to the premotor area) during either hand task in both groups. We conclude that the different patterns of ipsilateral activation might be mainly explained by the hemispheric dominance. The skill of the hand and complexity of tasks may be related to the predominant activation of the premotor area.

Adult↗

PubMed1998

Hemorrhage in pituitary adenoma: correlation of MR imaging with operative findings.

The aim of this study was to correlate MR imaging and operative findings of hemorrhage in pituitary macroadenomas. We retrospectively reviewed MR images of 113 surgically proven pituitary adenomas. All patients were examined on a 1.5-T MR system. The intensity of intratumoral cystic cavities was correlated with operative findings. In 15 patients with pituitary apoplexy, we determined relationship between interval of MR examination after apoplectic event and MR signal intensity. In 8 patients with repeated preoperative MR examination, we evaluated sequential changes of intratumoral hemorrhage. There were 54 cavities at surgery: 52 were hemorrhagic and 2 were nonhemorrhagic. Twenty-nine of 52 hemorrhagic cysts demonstrated high/low signal (H/L) fluid-fluid levels on T2-weighted image (T2WI). In 19 of them, two components could be separately seen at operation: the supernatant high-intensity area represented xanthochromic fluid, and the dependent low-intensity area represented liquefied hematoma. The H/L fluid-fluid level was observed predominantly in hematomas on MR images obtained after longer intervals. In patients with repeated MR examination, follow-up MR imaging revealed additional hemorrhage or new formation of fluid-fluid levels. It was surprising that 12 of 14 cysts preoperatively judged as nonhemorrhagic in fact contained hemorrhagic components. The preoperative MR images are well correlated to the operative findings in hemorrhagic pituitary macroadenomas. It proved that 52 of 54 cystic cavities had hemorrhagic component.

Adenoma↗

PubMed1998

Lymph node metastasis of early gastric cancer with submucosal invasion.

BACKGROUND: A clinicopathological study of early gastric cancer with submucosal invasion was carried out in relation to lymph node metastasis. METHODS: A retrospective study was conducted of 245 patients with submucosal gastric cancer treated by gastrectomy combined with D2 lymph node resection between 1985 and 1994 in a university hospital. RESULTS: Lymph node metastasis was observed in 34 patients (14 per cent). The mortality rate due to recurrence in patients with lymph node metastasis (three of 34) was significantly higher than in those without lymph node metastasis (five (2 per cent) of 211) (chi2 = 3.95, 1 d.f., P < 0.05). Tumour size, depth of invasion, lymphatic involvement of cancer cells and preoperative diagnosis of advanced cancer correlated significantly with the presence of lymph node metastasis. When the submucosal carcinomas were classified into three categories according to depth of invasion by dividing the submucosal (sm) layer into three equal parts, sm1, sm2 and sm3, the incidence of lymph node metastasis increased from 2 per cent to 12 and 20 per cent respectively. CONCLUSION: When the pathological report reveals sm1 invasion after laparoscopic or endoscopic surgery, reoperation should not be necessary because sm1-carcinomas with diameters of less than 2 cm do not usually metastasize to the lymph nodes.

Adult↗

PubMed1998

[The role of heat shock protein 60 (HSP60) of Helicobacter pylori in adhesion of H. pylori to human gastric epithelial cell].

Adhesion of Helicobacter pylori to both human gastric carcinoma cell lines (MKN45, MKN28 and KATO III) and prepared primary human gastric epithelial cells were analyzed with flow-cytometry. All strains adhered to human gastric carcinoma cells. Especially, these strains strongly adhered to MKN45 cells. Adhesion of H. pylori strains to prepared primary human gastric epithelial cells was also observed. However, the adherence rates of H. pylori to these cells were different among the cells used. These results suggested that the host factor might be important for adhesion of the bacteria to human gasgric cells. In addition, H20 monoclonal antibody directed to H. pylori HSP60 inhibited the adhesion of H. pylori to both cells. These results indicate that H. pylori HSP60 might be associated with the adhesion of the bacteria to human gastric epithelial cells.

Bacterial Adhesion↗

PubMed1998

Churg-Strauss syndrome diagnosed and followed with gastrointestinal fiberscopic studies and electroneuromyography.

Churg-Strauss syndrome (CSS) is a disorder characterized by hypereosinophilia and systematic vasculitis occurring in individuals with bronchial asthma. We present a case of 24-year-old woman with CSS diagnosed by and followed with gastrointestinal fiberscopic examination and electroneuromyography. The duodenal biopsy showed granulomatous angiitis with eosinophilic infiltration, and the electroneuromyography showed peripheral nerve dysfunction. After steroid treatment, the duodenal erosion and ulcer were almost completely resolved. There was no improvement in electroneuromyography, but the patient was able to walk independently after intensive rehabilitative training.

Adult↗

PubMed1998

Clinical implication of protein levels of IL-5 in induced sputum in asthmatic patients.

To determine whether protein levels of interleukin-5 (IL-5) in induced sputum reflect the degree of eosinophilic inflammation, we evaluated the role of IL-5 on clinical characteristics in stable asthmatic patients. IL-5 level, differential eosinophil count, and level of eosinophil cationic protein (ECP) in induced sputum were all significantly higher for asthmatics than for normal controls. Both eosinophil counts and ECP levels in induced sputum were inversely correlated with the degree of airflow limitation (FEV1/FVC). In addition, patients with measurable IL-5 in sputum had significantly more eosinophils, higher levels of ECP in sputum, and lower FEV1 (percent predicted) than did patients with levels of IL-5 beneath the limit of detection. However, we found no significant difference in IL-5 levels between atopic and nonatopic asthmatics. IL-5 level in induced sputum is a good indicator of eosinophilic inflammation in atopic and nonatopic asthmatic patients.

Adult↗

PubMed1998

[Efficacy of combination of ondansetron injection and tablet in CAF-induced emesis in breast cancer patients].

Efficacy of combination of ondansetron injection and tablet on CAF (cyclophosphamide, adriamycin, 5-fluorouracil) induced emesis were investigated in 10 breast cancer patients (33 courses). Complete suppression rate of nausea or vomiting were approximately 75%, approximately 90% respectively for every treatment day. According to judgement criteria, antiemetic rate of approximately 100% was achieved during the study period. As to food intake of each treatment day, in approximately 70% of treatment courses was assessed as '(patient was) able to eat most of the meal'. Trend in emetic episodes and food intake in each patient receiving several courses of CAF therapy were evaluated. As a result, those patients experiencing nausea or vomiting or had effect on their food intake, were found to be in the similar condition in the following course (s) of CAF. No adverse drug reaction nor clinical laboratory test abnormalities due to ondansetron was observed. In this investigation, combination of ondansetron injection and tablet was shown to sufficiently suppress CAF-induced nausea and vomiting, and their efficacy was confirmed. Still, the study suggested that number of emetic episodes or degree of anorexia differs according to each individual. Therefore we regard additional administration of ondansetron or concomitant use of steroids should be considered when necessary.

Administration, Oral↗

PubMed1998

Functional MR imaging of cortical activation of the cerebral hemispheres during motor tasks.

PURPOSE: We used functional MR imaging to evaluate cortical activation in the precentral, central, and postcentral regions of the contralateral and ipsilateral cerebral hemispheres during left- and right-handed motor tasks. METHODS: Ten healthy right-handed volunteers were studied with echo-planner MR imaging (1.5 T) while performing alternating finger apposition tasks with both hands. During the hand tasks, the areas of activated pixels were compared between subregions (precentral, central, and postcentral) of the contralateral and ipsilateral sensorimotor cortex. RESULTS: The activated area of the contralateral sensorimotor cortex was significantly larger than that of the ipsilateral cortex during tasks with either hand, whereas the ipsilateral activated area was significantly larger during the left-handed task than during the right-handed task. Ipsilateral activation was greatest in the precentral region, less in the central region, and least prominent in the postcentral region. CONCLUSIONS: Our results confirmed those of previous investigators that ipsilateral activation is more pronounced during left-sided movements than during right-sided movements. The variation in activation of the precentral, central, and postcentral subregions suggests different roles of the ipsilateral and contralateral hemispheres during motor tasks.

Adult↗

PubMed1997

Correlation of lesions in the hippocampal region noted on MR images with clinical features.

The purpose of our work was to compare the MR imaging findings of obvious hippocampal and/or juxtahippocampal lesions with corresponding clinical features. Magnetic resonance images of 63 patients with obvious lesions in the hippocampal and/or juxtahippocampal regions were reviewed and their findings were correlated with patients' clinical characteristics. Based on the MR and clinical findings, the patients were divided into four groups: (a) 26 patients with space occupying lesions or suspected vascular malformation frequently causing symptomatic temporal epilepsy; (b) 14 with hippocampal infarcts, which when left-sided or bilateral caused amnesia; (c) 11 with encephalitis and 5 with old temporal contusion usually accompanied by both amnesia and epilepsy; and (d) 7 with temporal atrophy and progressive dementia of subacute onset. Magnetic resonance imaging allows precise localization and evaluation of the clinical correlates of hippocampal and juxtahippocampal lesions, which frequently caused symptomatic temporal epilepsy and/or amnesic syndrome.

Adolescent↗

PubMed1997

CT and MR imaging of craniopharyngioma.

We reviewed imaging findings of CT and MR imaging in 20 cases of surgically confirmed craniopharyngioma in an attempt to determine their relation to patterns of tumor extent. The relationship between these patterns and the frequency of preoperative CT diagnosis and MR imaging diagnosis according to the surgical diagnosis were determined. The CT technique was superior to MR imaging in the detection of calcification. The MR imaging technique was superior to CT for determining tumor extent and provided valuable information about the relationships of the tumor to surrounding structures. Thus, CT and MR imaging have complementary roles in the diagnosis of craniopharyngiomas. In cases of possible craniopharyngioma, noncontrast sagittal T1-weighted images may enable the identification of the normal pituitary, possibly leading to the correct diagnosis.

Adolescent↗

PubMed1997

Relationship between isocapnic buffering and maximal aerobic capacity in athletes.

This study was performed to clarify the relationship between isocapnic buffering and maximal aerobic capacity (VO2max) in athletes. A group of 15 trained athletes aged 21.1 (SD 2.6) years was studied. Incremental treadmill exercise was performed using a modified version of Bruce's protocol for determination of the anaerobic threshold (AT) and the respiratory compensation point (RC). Ventilatory and gas exchange responses were measured with an aeromonitor and expressed per unit of body mass. Heart rate and ratings of perceived exertion were recorded continuously during exercise. The mean VO2max, oxygen uptake (VO2) at AT and RC were 58.2 (SD 5.8) ml x kg(-1) x min(-1), 28.0 (SD 3.3) ml x kg(-1) x min(-1) and 52.4 (SD 6.7) ml x kg(-1) x min(-1), respectively. The mean values of AT and RC, expressed as percentages of VO2max, were 48.3 (SD 4.2)% and 90.0 (SD 5.2)%, respectively. The mean range of isocapnic buffering defined as VO2 between AT and RC was 24.4 (SD 4.5) ml x kg(-1) x min(-1), and the mean range of hypocapnic hyperventilation (HHV) defined as VO2 between RC and the end of exercise was 5.8 (SD 3.0) ml x kg(-1) x min(-1). The VO2max per unit mass was significantly correlated with AT (r = 0.683, P < 0.01). In addition, VO2max/mass was closely correlated with both the range of isocapnic buffering (r = 0.803, P < 0.001) and RC (r = 0.878, P < 0.001). However, no correlation was found between VO2max per unit mass and the range of HHV (r = 0.011, NS.). These findings would suggest that the prominence of isocapnic buffering, in addition to the anaerobic threshold, may have been related to VO2max of the athletes. The precise mechanisms underlying this proposed relationship remain to be elucidated.

Adult↗

PubMed1997

Molting hormonal and larvicidal activities of aliphatic acyl analogs of dibenzoylhydrazine insecticides.

Dibenzoylhydrazines are the nonsteroidal ecdysone agonists. Using comparative molecular field analysis, we previously found that the alkyl side chain of 20-hydroxyecdysone (20E) is three-dimensionally superposable with one of their two aryl moieties. To identify the aryl moiety that is better superposable on the alkyl chain, we synthesized compounds in which one of the two aryl groups of tebufenozide (N-t-butyl-N-3,5-dimethylbenzoyl-N'-4-ethylbenzoylhydrazine) is replaced by alkyl groups such as C4H9, C5H11, and C6H13. The molting hormonal activity of these compounds was measured using cultured integuments prepared from rice stem borers, Chilo suppressalis Walker, in terms of stimulation of incorporation of N-acetyl-[14C]glucosamine. N-t-Butyl-N-3,5-dimethylbenzoyl-N'-acylhydrazines with a hexanoyl or heptanoyl group were about 20-fold higher than that of 20E, whereas N-acyl-N-t-butyl-N'-4-ethylbenzoylhydrazines with a hexanoyl or heptanoyl group were much weaker than 20E. Their larvicidal activity was also measured against rice stem borers. The former series of compounds were much more active than the other series as well as 20E. Thus, the benzoyl moiety of dibenzoylhydrazines, which is bound to the secondary nitrogen atom (-NH-), is replaceable by aliphatic acyl groups without greatly affecting the biological activities.

Acylation↗

PubMed1997

Supratentorial primary intra-axial tumors in children. MR and CT evaluation.

PURPOSE: To evaluate the MR and CT features of pediatric supratentorial intra-axial tumors with respect to differential diagnosis and the role of each investigation modality. MATERIAL AND METHODS: MR and CT findings in 40 children with 12 types of pathologically proven histological tumors were reviewed. RESULTS: The location of tumors might be one clue to differential diagnosis. In our material, cysts (60%), calcifications (45%), and intratumoral hemorrhages (27%) were found in the tumors. Characteristic features noted in some lesions included: peritumoral hemosiderin deposition in cavernous angiomas; intratumoral flow void in a choroid plexus carcinoma and in glioblastomas; and hemicerebral atrophy in germinomas. A comparison between malignant and benign tumors showed perifocal edema and a mass effect to be significantly more common in malignant lesions. Homogeneous enhancement suggested a benign tumor and an inhomogeneous pattern represented malignancy, while the lack of obvious enhancement did not always suggest benignity. Intratumoral calcium deposition was a not uncommon finding in malignant tumors. CONCLUSION: In most cases, the exact diagnosis should be made by histological examination but it is important for treatment planning that the appropriate depiction of tumor extension and tissue characterization be made by MR and CT.

Adolescent↗

PubMed1997

Heat-shock protein 60 homologue of Helicobacter pylori is associated with adhesion of H. pylori to human gastric epithelial cells.

A previous study reported a relationship between the expression of heat-shock protein 60 (HSP60) by Helicobacter pylori and its adhesion to human gastric carcinoma (MKN45) cells. To examine whether the HSP60 homologue of H. pylori is associated with the adhesion of H. pylori to human gastric epithelial cells, an inhibition assay of adhesion of H. pylori to MKN45 cells was performed by flow cytometric analysis with monoclonal antibody (MAb) designated as H20 recognising HSP60 of H. pylori. The rate of adhesion of H. pylori pretreated with MAbH20 to MKN45 cells was lower than that of untreated H. pylori. Primary human gastric epithelial cells from a patient with gastric cancer were also prepared for comparison in the inhibition assay with MAbH20. H. pylori adhered to the primary human gastric epithelial cells, and this adhesion was significantly inhibited by MAbH20. These results suggest that the H. pylori HSP60 homologue recognised by MAbH20 might be associated with the adhesion of H. pylori to primary human gastric epithelial cells as well as to cultured gastric cancer cells.

Adhesins, Bacterial↗

PubMed1997

Effect of exercise training and detraining on gas exchange kinetics in patients with chronic obstructive pulmonary disease.

Symptom-limited incremental exercise tests are used to estimate the training effect on patients with chronic obstructive pulmonary disease (COPD). However, there is a need for objective parameters for measurement on submaximal exercise testing. The purpose of this study was to assess the usefulness of measurement of oxygen uptake (VO2) kinetics during a constant work rate exercise test of patients with COPD after exercise training. Eleven patients with COPD performed exercise tests before and after cycle ergometer training on 3 days per week for 8 weeks; they then went without training for 5 months and performed the same tests. They performed an incremental exercise test to symptom-limited maximum and a constant work rate exercise test for 6 min on a cycle ergometer. The time constant of VO2 during the onset of constant work rate exercise was significantly decreased (from 63.5 +/- 7.8 s to 53.2 +/- 8.0 s) after exercise training (P = 0.021), but was significantly increased (to 73.4 +/- 14.9 s) after 5 months without training (P = 0.001). The oxygen pulse at steady state during constant work rate exercise testing was significantly increased after exercise training but decreased 5 months later. The change in blood lactate from rest to steady state during constant work rate exercise was significantly decreased after exercise training, but increased 5 months later. Measurement of the time constant of VO2 and oxygen pulse during constant work rate exercise are useful for the objective evaluation of the training effect of patients with COPD.

Aged↗

PubMed1997

Adenosine modulates endothelin-induced bronchoconstriction in guinea pig airway.

The present study was designed to determine whether endogenous and exogenous adenosine modulates endothelin (ET)-induced bronchoconstriction. Exogenous adenosine enhances ET-induced bronchoconstriction. Following pretreatment with adenosine deaminase and theophylline to eliminate or antagonize endogenous adenosine, ET-1-induced bronchoconstriction was significantly attenuated, but not that of ET-3. In conclusion, this is the first report of an enhancement of ET-induced bronchoconstriction of guinea pig airways by endogenous and exogenous adenosine. Our findings may be useful in designing specific adenosine receptor antagonists as therapeutic agents in the management of bronchial asthma.

Acetylcholine↗

PubMed1997

Synergistic effect of nitric oxide and vasoactive intestinal peptide on bronchoprotection against histamine in anesthetized guinea pigs.

Vasoactive intestinal peptide (VIP) and nitric oxide (NO) are considered to be nonadrenergic, noncholinergic (NANC) inhibitory neurostransmitters in the airways. It seems likely that these neurotransmitters may be coreleased and act as functional antagonists against bronchoconstrictor stimuli. In the present study, we examined the synergistic effect of NO and VIP on bronchoprotection against histamine in anesthetized guinea pigs. The NO donor, S-nitroso-N-acetylpenicillamine (SNAP) significantly inhibited histamine-induced bronchoconstriction in a dose-dependent manner. VIP also inhibited histamine-induced bronchoconstriction in a dose-dependent manner, but this bronchoprotective effect was short-lived. Additionally, VIP (10(-9) M) had no significant bronchoprotective effect, but a subthreshold dose of SNAP (10(-7) M) significantly potentiated VIP (10(-9) M)-induced bronchoprotection against histamine. Moreover, SNAP (10(-7) M) significantly enhanced VIP (10(-7) M)-induced bronchoprotection for a longer period of time. On the other hand, VIP (10(-9) M) also significantly potentiated SNAP-induced bronchoprotection against histamine. In conclusion, combination therapy with NO donor and VIP receptor agonist may have important advantages in the treatment of bronchial asthma, and both NO and VIP may contribute in complementary fashion to the NANC-induced relaxant response in guinea pig airways.

Anesthesia↗