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Biomedical subjects

N Narita

Publications and source records attributed to N Narita.

At least 19 recordsLinked to original sources
PubMed2001

Distribution of muscle mass and maximal exercise performance in patients with COPD.

STUDY OBJECTIVE: To investigate the distribution of reduction in lean body mass (LBM) and whether LBM in legs (LBMlegs) can be a determinant of maximal exercise performance in COPD patients. METHODS: Thirty-eight male outpatients with COPD (mean +/- SD FEV1, 47.4 +/- 24.0% of predicted) who underwent complete pulmonary function testing were classified into two groups according to FEV1 expressed as a percentage of predicted value. Group A comprised 21 patients with mild-to-moderate airflow limitation (FEV(1) > or =35% predicted), and group B comprised 17 patients with severe airflow limitation (FEV1 < 35% predicted). LBM, which represents skeletal muscle mass, was measured by dual energy x-ray absorptiometry (DXA) and was assessed separately in arms, legs, and trunk. Maximal oxygen uptake VO2max was measured during maximal exercise on a cycle ergometer. RESULTS: LBM in each region was expressed as a percentage of ideal body weight (IBW). LBM in arms (LBMarms)/IBW, LBMlegs/IBW, and LBM in trunk (LBMtrunk)/IBW were significantly depleted in group B compared with group A (p < 0.01). LBMlegs expressed as a percentage of total LBM (LBMlegs/total LBM) was significantly lower in group B (p < 0.05), although there was no significant difference in LBMarms/total LBM and LBMtrunk/total LBM between the two groups. VO2max correlated significantly with LBMlegs/IBW in group A, but not in group B. By stepwise regression analysis, LBMlegs/IBW appeared to be a significant predictor of VO2max in group A, while not in group B. CONCLUSION: LBMlegs was a significant predictor of maximal exercise performance in patients with mild-to-moderate airflow limitation, but not in patients with severe airflow limitation who had disproportional reduction in LBMlegs.

Absorptiometry, Photon↗
PubMed2001

Serotonin transporter gene variation is a risk factor for sudden infant death syndrome in the Japanese population.

OBJECTIVE: Serotonin (5-HT) in the nervous system is a major factor in facilitation of the brain center for respiration. Variations in the promoter region of the 5-HT transporter (5-HTT) gene have been shown to potentially regulate 5-HT activity in the brain. Therefore, we aimed to identify the possibility that specific allele variants of the 5-HTT gene can be found as a genetic background for sudden infant death syndrome (SIDS). METHODS: Polymorphisms in the 5' regulatory region of the 5-HTT gene were determined in genomic DNA obtained from 27 SIDS victims and 115 age-matched health control participants. RESULTS: There were significant differences in genotype distribution and allele frequency of the 5-HTT promoter gene between SIDS victims and age-matched control participants. The L and XL alleles were more frequently found in SIDS victims than in age-matched control participants. CONCLUSION: Efficiency in the transportation of 5-HTT with the L allele is known to be higher than that with the S allele. The excitatory function by 5-HT is considered to be lower in the respiratory center of individuals with the L allele compared with those with S allele. The XL allele variant has shown another novel biological risk factor for SIDS.

Carrier Proteins↗
PubMed2001

[Effective use of camostat mesilate for chronic disseminated intravascular coagulation complicated by thoracoabdominal aortic aneurysm].

A 73-year-old man who had been receiving treatment for hypertension and angina pectoris was admitted to hospital following a transient ischemic attack. He was diagnosed as having chronic disseminated intravascular coagulation (DIC) complicated by a thoracoabdominal aortic aneurysm, and was treated with heparin sodium and a protease inhibitor. Although the DIC was controlled, the patient had to remain hospitalized in order to receive the medication by continuous infusion. Therefore, the heparin sodium and protease inhibitor were replaced by camostat mesilate, a drug suitable for oral administration and widely used for treatment of chronic pancreatitis. The drug proved effective for the chronic DIC, thus allowing the patient to receive regular treatment on an outpatient basis, and improving his quality of life.

Administration, Oral↗
PubMed2000

Mechanism of action of aragusterol a (YTA0040), a potent anti-tumor marine steroid targeting the G(1) phase of the cell cycle.

Aragusterol A (YTA0040), isolated from the Okinawan marine sponge of the genus Xestospongia, is a potent anti-tumor marine steroid that possesses a unique structural component. This compound showed broad-spectrum anti-proliferative activity against a panel of 14 human cancer cell lines (IC(50) = 0.01-1.6 microM). P-glycoprotein-mediated, multidrug-resistant cells showed cross-resistance to YTA0040 cells, whereas cisplatin-resistant non-small-cell lung-cancer (NSCLC) sublines showed a collateral sensitivity to YTA0040. In transplantable murine tumor models, YTA0040 displayed a broad spectrum and high degree of anti-tumor activity when administered i.p. or p.o. (life span T/C = 135-234%). In P388 murine leukemia cells, YTA0040 caused dose- and time-dependent suppression of nucleic acid and protein synthesis, with protein synthesis being more potently and rapidly inhibited than nucleic acid synthesis. Flow-cytometric analysis revealed that YTA0040 blocked the entry of human NSCLC-derived A549 cells into S phase, leading to arrest in the G(1) phase of the cell cycle. Western blot analysis demonstrated that YTA0040 caused a dose-dependent decrease in the levels of expression of hyperphosphorylated pRb and cyclin A in A549 cells. The level of p53 protein expression was decreased by YTA0040 treatment. A higher concentration of YTA0040 down-regulated the levels of expression of CDK2, CDK4, cyclin D1 and cyclin E. These findings indicated that YTA0040 arrested human NSCLC cells in late G(1) phase of the cell cycle through inhibition of pRb phosphorylation. Inhibition of pRb phosphorylation by YTA0040 resulted from down-regulation of levels of expression of the CDKs and cyclins involved in the G(1)/S transition and not from induction of p53 and/or the CDK inhibitor p21.

Animals↗
PubMed2000

Defective T cell function for inhibition of growth of Mycobacterium avium-intracellulare complex (MAC) in patients with MAC disease: restoration by cytokines.

To define the immunopathologic mechanism underlying pulmonary Mycobacterium avium-intracellulare complex (MAC) disease in patients without AIDS, the ability of CD4(+) and gammadelta T cells to induce growth inhibition of MAC in monocytes was compared between patients and healthy control subjects. T cell-dependent growth inhibition and production of interferon-gamma and macrophage colony-stimulating factor decreased in patients. CD4(+) T and gammadelta T cells from patients were equally defective in inducing anti-MAC activity. The combination of these cytokines restored the ability of patients' T cells to control MAC growth. In experiments with allogeneic cocultures of gammadelta T cells and infected monocytes from patients and control subjects, healthy control T cells could augment growth inhibition of MAC in monocytes from patients, whereas patients' T cells could not, even in the presence of healthy control monocytes. These results indicate that the defect in T cells may be associated with impaired protective immunity against MAC in these patients.

Aged↗
PubMed2000

Ectopic p16(ink4) expression enhances CPT-11-induced apoptosis through increased delay in S-phase progression in human non-small-cell-lung-cancer cells.

A tumor-suppressor gene, p16(INK4), which is deleted or mutated in tumors, regulates cell-cycle progression through a G(1)-S restriction point by inhibiting CDK4(CDK6)/cyclin-D-mediated phosphorylation of pRb. We have found that ectopic p16(INK4) expression increased cellular sensitivity of human non-small-cell-lung-cancer (NSCLC) A549 cells to a selective growth-inhibitory effect induced by the topoisomerase-I inhibitor 11, 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxy camptothecin (CPT-11) in vitro. In this study, we observed enhanced apoptosis characterized by DNA fragmentation in A549 cells transfected with p16(INK4) cDNA (A549/p16-1) and treated with CPT-11. This apoptosis was suppressed by the inhibitor of interleukin-1beta-converting enzyme (ICE/caspase-1) or ICE-like proteases, Z-Asp-CH2-DCB, as determined by DNA fragmentation and proteolytic cleavage of poly(ADP-ribose) polymerase, a natural substrate for CPP32/caspase-3. In A549/p16-1 cells, cytosolic peptidase activities that cleaved Z-DEVD-7-amino-4-trifluoromethylcoumarin increased during CPT-11-induced apoptosis and were suppressed by a highly specific caspase-3 and caspase-3-like inhibitor, Z-DEVD-fluoromethylketone. These findings indicate that p16(INK) is positively involved in the activation pathway of the caspase-3 induced by CPT-11. The increased delay in S-phase progression and subsequent induction of apoptosis were observed in CPT-11-treated A549/p16-1 cells on the basis of DNA histograms. Specific down-regulation of the cyclin-A protein level in A549/p16-1 cells was observed after CPT-11-treatment, whereas cyclin B, cdk2, and cdc2 protein levels were unaffected. These results suggest that ectopic p16(INK4) expression inappropriately decreases cyclin A and thereby terminates CPT-11-induced G(2)/M accumulation, which is followed by increased apoptosis in p16(INK4)-expressing A549 cells.

Antineoplastic Agents, Phytogenic↗
PubMed2000

Clinical evaluation of 99mTc-Technegas SPECT in thoracoscopic lung volume reduction surgery in patients with pulmonary emphysema.

UNLABELLED: 99mTc-Technegas (Tcgas) SPECT is useful for evaluating the patency of the airway and highly sensitive in detecting regional pulmonary function in pulmonary emphysema. The aim of this study is to evaluate regional ventilation impairment by this method pre and post thoracoscopic lung volume reduction surgery (LVRS) in patients with pulmonary emphysema. METHODS: There were 11 patients with pulmonary emphysema. The mean age of patients was 64.1 years. All patients were males. LVRS was performed bilaterally in 8 patients and unilaterally in 3 patients. Post inhalation of Tcgas in the sitting position, the subjects were placed in the supine position and SPECT was performed. Distribution of Tcgas on axial images was classified into 4 types, A: homogeneous, B: inhomogeneous, C: hot spot, D: defect. Three slices of axial SPECT images, the upper, middle and lower fields were selected, and changes in deposition patterns post LVRS were scored (Tcgas score). RESULTS: Post LVRS, dyspnea on exertion and pulmonary function tests were improved. Pre LVRS, inhomogeneous distribution, hot spots and defects were observed in all patients. Post LVRS, improvement in distribution was obtained not only in the surgical field and other fields, but also in the contralateral lung of unilaterally operated patients. In 5 patients some fields showed deterioration. The Tcgas score correlated with improvements in FEV1.0, FEV1.0% and %FEV1.0. CONCLUSION: Tcgas SPECT is useful for evaluating changes in regional pulmonary function post LVRS.

Aged↗
PubMed2000

The relation of fat-free mass to maximum exercise performance in patients with chronic obstructive pulmonary disease.

To assess the factors determining maximum exercise performance in patients with chronic obstructive pulmonary disease (COPD), we examined nutritional status with special reference to body composition and pulmonary function in 50 stable COPD patients. Nutritional status was evaluated by body weight and body composition, including fat mass (FM) and fat-free mass (FFM) assessed by bioelectrical impedance analysis (BIA). Exercise performance was evaluated by maximum oxygen uptake (Vo(2max)) on a cycle ergometer. A total of 50 patients (FEV(1) = 0.98 L) was divided randomly into either a study group (group A, n = 25) or validation group (group B, n = 25). Stepwise regression analysis was performed in group A to determine the best predictors of Vo(2max) from measurements of pulmonary function and nutritional status. Stepwise regression analysis revealed that Vo(2max) was predicted best by the following equation in group A: Vo(2max) (mL/min) = 10.223 x FFM (kg) + 4.188 x MVV (L/min) + 9.952 x DL(co) (mL/min/mmHg) - 127.9 (r = 0.84, p < 0. 001). This equation was then cross-validated in group B: Measured Vo(2max) (mL/min) = 1.554 x Predicted Vo(2max) (mL/min) - 324.0 (r = 0.87, p < 0.001). We conclude that FFM is an important factor in determining maximum exercise performance, along with pulmonary function parameters, in patients with COPD.

Aged↗
PubMed2000

Pulmonary veno-occlusive disease in pulmonary Langerhans' cell granulomatosis.

This report describes unusual clinical and pathological findings in a 29-yr-old female with pulmonary Langerhans' cell granulomatosis (LCG). During a 7-yr clinical course her condition deteriorated despite corticosteroid therapy, and she died of respiratory failure and pulmonary hypertension. At autopsy, there were widespread pulmonary veno-occlusive disease (PVOD) lesions as well as abundant advanced and healed lesions of pulmonary LCG composed of multiple cysts and stellate fibrosis. The present case demonstrates that pulmonary Langerhans' cell granulomatosis should be considered as a possible cause of pulmonary veno-occlusive disease.

Adult↗
PubMed2000

[Dissecting aneurysm of the middle cerebral artery: case report].

We present a surgical case of a dissecting aneurysm of the right middle cerebral artery associated with subarachnoid hemorrhage and intracranial hemorrhage. A 61-year-old woman with consciousness disturbance and left hemiplegia was referred to our hospital. She had suffered severe headache for a week. CT scan showed a subarachnoid hemorrhage in the right Sylvian fissure and intracranial hemorrhage in the right putamen. The right carotid angiogram revealed string sign in M1 portion and occlusion at M2 lower branch of the right middle cerebral artery. On the 12th day, we undertook surgery to confirm whether it was a dissecting aneurysm or not. In the operation, it was reddish in the M1 portion corresponding to the "string sign" and dark-purplish in the lower M2 portion corresponding to an "aneurysm-like lesion". To prevent bleeding, the arterial wall in the M1 portion was coated using muscle. Though the left hemiplegia was unchanged, the postoperative course was uneventful. The patient was transferred to another hospital and underwent rehabilitation. There has been no reccurrence during the four years since surgery. The middle cerebral artery dissecting aneurysm is extremely rare. We presented this case with review of the literature.

Aortic Dissection↗
PubMed2000

[A case of a pituitary mass in association with sarcoidosis].

We report a case of a pituitary mass associated with sarcoidosis. Natural regression of the mass was demonstrated after the replacement of corticosteroid hormone. A seventy-one-year old man presented with blurred vision and general fatigability, and admitted to our hospital. He was diagnosed to have ophthalmic and pulmonary sarcoidosis. Two months later, he consulted our hospital again, with complaints of fatigability and vomiting. Laboratory data showed hyponatremia, and CT scan revealed a suprasellar mass. He had no neurological deficits. Diabetes insipidus was not observed. Magnetic resonance image showed a heterogeneously enhanced intrasellar and suprasellar dumbbell shaped mass and thickening of the pituitary stalk. Hormonal examination revealed corticosteroid insufficiency and hypothyroidism, possibly caused by the pituitary mass. Replacement of corticosteroid hormone significantly improved his fatigability. Two months later, follow-up MRI showed regression of the pituitary mass. Based on the clinical and radiological findings, pituitary mass was strongly suggested to be caused by sarcoidosis. We recommend prompt steroid treatment for such a pituitary mass and strict follow-up MRI study.

Aged↗