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T Nagase

Publications and source records attributed to T Nagase.

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

Effects of lung volume on airway resistance during induced constriction in papain-treated rabbits.

It has been reported that both the elasticity of the cartilage and airway-parenchymal interdependence can modify shortening of the airway smooth muscle and airway narrowing during induced constriction. We hypothesized that induced softening of the cartilage could alter airway compliance and/or the forces of mechanical interdependence, resulting in an increased degree of airway narrowing in response to a contractile stimulus. To test this hypothesis, we compared the effects of changing lung volume on airway resistance (Raw) under baseline conditions and during methacholine (MCh)-induced constriction in papain-treated (n = 6) and control rabbits (n = 6). With use of the alveolar capsule technique, Raw was directly measured under baseline conditions at different levels of end-expiratory transpulmonary pressure (Ptp = 4-12 cmH2O). Then aerosolized MCh was delivered (0.2-25 mg/ml) and measurements were performed at different levels of Ptp (4 and 12 cmH2O). From measured tracheal flow and tracheal and alveolar pressure in open-chest animals during mechanical ventilation (tidal volume = 6 ml/kg, breathing frequency = 1 Hz), we calculated Raw by subtracting tissue resistance from lung resistance. Papain treatment significantly increased Raw both under baseline conditions and after induced constriction. We found that increasing Ptp decreased Raw before and after MCh in both groups; however, the effects of changing Ptp on Raw were less in papain-treated animals. These observations suggest that both cartilage elasticity and mechanical interdependence are important determinants of airway smooth muscle shortening. The observation that volume dependence of Raw was less in papain-treated animals is consistent with the hypothesis that papain effects significant changes in the parenchymal attachments.

Airway Resistance↗
PubMed1996

Lung tissue behavior in the mouse during constriction induced by methacholine and endothelin-1.

Recently, mice have been extensively used to investigate the pathogenesis of pulmonary disease because appropriate murine models, including transgenic mice, are being increasingly developed. However, little information about the lung mechanics of mice is currently available. We questioned whether lung tissue behavior and the coupling between dissipative and elastic processes, hysteresivity (eta), in mice would be different from those in the other species. To address this question, we investigated whether tissue resistance (Rti) and eta in mice would be affected by varying lung volume, constriction induced by methacholine (MCh) and endothelin-1 (ET-1), and high-lung-volume challenge during induced constriction. From measured tracheal flow and tracheal and alveolar pressures in open-chest ICR mice during mechanical ventilation [tidal volume = 8 ml/kg, frequency (f) = 2.5 Hz], we calculated lung resistance (RL), Rti, airway resistance (Raw), lung elastance (EL), and eta (= 2piRti/EL). Under baseline conditions, increasing levels of end-expiratory transpulmonary pressure decreased Raw and increased Rti. The administration of aerosolized MCh and intravenous ET-1 increased RL, Rti, Raw, and EL in a dose-dependent manner. Rti increased from 0.207 +/- 0.010 to 0.570 +/- 0.058 cmH2O.ml-1.s after 10(-7) mol/kg ET-1 (P < 0.01). After induced constriction, increasing end-expiratory transpulmonary pressure decreased Raw. However, eta was not affected by changing lung volume, constriction induced by MCh and ET-1, or high-lung-volume challenge during induced constriction. These observations suggest that 1) eta is stable in mice regardless of various conditions, 2) Rti is an important fraction of RL and increases after induced contriction, and 3) mechanical interdependence may affect airway smooth muscle shortening in this species. In mammalian species, including mice, analysis of eta may indicate that both Rti and EL essentially respond to a similar degree.

Airway Resistance↗
PubMed1996

Intercellular adhesion molecule-1 mediates acid aspiration-induced lung injury.

Acid-aspiration-induced injury is one of the leading causes of adult respiratory distress syndrome. Intercellular adhesion molecule-1 (ICAM-1) is a ligand for lymphocyte-function-associated antigen-1 alpha (LFA-1 alpha), and it has been shown to be required for leukocyte migration into inflamed areas. The purpose of this report was to investigate the role of the ICAM-1/LFA-1 alpha pathway in a rat model of acid-aspiration-induced injury. Animals received 3.0 ml/kg HCI (0.1N; pH, 1.0) intratracheally pretreated with control monoclonal antibodies (mAbs) (HCI group) or anti-ICAM-1 and LFA-1 alpha mAbs (Test group). In the HCI group, increases in lung resistance (RL) (229 +/- 23% baseline), lung wet-to-dry weight ratio (W/D) (11.9 +/- 0.4), protein concentration (TP) (0.447 +/- 0.054 mg/ml), and the number of neutrophils (PMN) (159.0 +/- 19.4 x 10(4)) of bronchoalveolar lavage fluid were observed. In the Test group, HCI-induced injury was significantly reduced (RL, 122 +/- 7% baseline; W/D, 7.2 +/- 0.1; TP, 0.277 +/- 0.016 mg/ml; PMN, 8.8 +/- 0.8 x 10(4)). The administration of mAbs to ICAM-1 and LFA-1 alpha after HCI instillation partially attenuated HCI-induced responses. These observations suggest that the ICAM-1/LFA-1 alpha pathway might be involved in the pathogenesis of adult respiratory distress syndrome caused by acid aspiration.

Animals↗
PubMed1996

Roles of calcitonin gene-related peptide (CGRP) in hyperpnea-induced constriction in guinea pigs.

It has been reported that hyperpnea-induced bronchoconstriction in guinea pigs is a potential model for exercise-induced asthma in humans. We hypothesized that calcitonin gene-related peptide (CGRP) could modulate leukotriene D4 (LTD4)-induced responses and be involved in the pathophysiology in this asthma model. We measured tracheal (Ptr) and alveolar pressure (PA) using alveolar capsules in open-chested, mechanically ventilated (f = 1 Hz, VT = 9 ml/kg, PEEP = 4 cm H2O) guinea pigs. Animals were intravenously pretreated with saline (SAL), CGRP(8-37) (CGRP receptor antagonist), CGRP, MK-571 (LTD4 receptor antagonist), MK-886 (5-lipoxygenase inhibitor), or CGRP(8-37) + MK-571, and then underwent dry gas hyperpnea challenge (HC, 95% 02-5% CO2, 150 breaths/min, 7 min). We calculated resistance of lung (RL), tissue (Rti), and airway (Raw). HC increased RL, Rti, and Raw in SAL controls (322 +/- 27, 430 +/- 59, 299 +/- 23% baseline, respectively). MK-571, MK-886, and CGRP significantly reduced the responses to HC, while CGRP(8-37) enhanced HC-induced responses. Pretreatment with CGRP(8-37) and MK-571 in combination attenuated HC-induced constriction. In addition, pretreatment with CGRP reduced responses induced by intravenous administration of LTD4. These observations suggest that CGRP might be involved in the pathophysiology of hyperpnea-induced constriction in guinea pigs via modulation of LTD4-elicited responses.

Animals↗
PubMed1996

[Longevity science research retrieval system using the thesaurus specifically developed for the science].

Gerontology is a new field including various disciplines such as medicine, engineering science, social science etc, and is sometimes called as "longevity science". Because of the wide area of the field, it is important to show the scope of the science and the development of its thesaurus contributes to this end. We developed a relevant thesaurus based on the research funded by Longevity Science Promotion Organization, and using the thesaurus, we also developed a database and retrieval system of the gerontology research. This system can be accessed on the Internet.

Aged↗
PubMed1996

Expression of immunoreactive activin A protein in remodeling lesions associated with interstitial pulmonary fibrosis.

The expression of activin A, one of the transforming growth factor-beta supergene family, was studied in various pulmonary conditions associated with interstitial pulmonary fibrosis (3 cases with diffuse alveolar damage, 6 cases with idiopathic pulmonary fibrosis, and 1 case with pulmonary fibrosis associated with rheumatoid arthritis) using immunohistochemical techniques on paraffin-embedded sections. Controls consisted of 10 cases with normal pulmonary parenchyma, and 2 cases with primary pulmonary hypertension and 1 case with secondary pulmonary hypertension were also studied. The lung specimens from normal parenchyma weakly expressed immunoreactive activin A on the bronchiolar epithelium. In marked contrast, all of the specimens from cases with diffuse alveolar damage and interstitial pulmonary fibrosis demonstrated strong expression of activin A on metaplastic epithelium, hyperplastic smooth muscle cells, desquamated cells, and alveolar macrophages. Pulmonary arteries from patients with primary or secondary pulmonary hypertension showed abundant immunoreactive activin A on smooth muscle cells. These findings suggest a potential role for this growth factor, activin A, in the pathogenesis of pulmonary tissue remodeling associated with interstitial pulmonary fibrosis.

Activins↗
PubMed1996

Object-oriented analysis and design of an ECG storage and retrieval system integrated with an HIS.

For a hospital information system, object-oriented methodology plays an increasingly important role, especially for the management of digitized data, e.g., the electrocardiogram, electroencephalogram, electromyogram, spirogram, X-ray, CT and histopathological images, which are not yet computerized in most hospitals. As a first step in an object-oriented approach to hospital information management and storing medical data in an object-oriented database, we connected electrocardiographs to a hospital network and established the integration of ECG storage and retrieval systems with a hospital information system. In this paper, the object-oriented analysis and design of the ECG storage and retrieval systems is reported.

Computers↗
PubMed1995

A human homolog of the mitochondrial protein import receptor Mom19 can assemble with the yeast mitochondrial receptor complex.

Import of preproteins into mitochondria requires transport machineries in both mitochondrial membranes that have been characterized in Saccharomyces cerevisiae and Neurospora crassa. By cDNA analysis, we identified a human protein of 16 kDa with significant overall homology to the fungal mitochondrial import receptor Mom19, including the three typical characteristics: a hydrophobic N-terminal segment, a tetratrico peptide motif in the middle and a negatively charged C-terminus. The human Mom19 homolog is expressed in all tissues analyzed. When synthesized in vitro, the human Mom19 homolog is targeted to isolated yeast mitochondria and specifically associates with the outer membrane receptor complex, suggesting that indeed a mitochondrial import receptor was identified.

Amino Acid Sequence↗
PubMed1995

Structure-activity relationships of cyclic pentapeptide endothelin A receptor antagonists.

Analogues of the natural product endothelin A (ETA) receptor antagonists cyclo(-D-Trp1-D-Glu2-Ala3-D-Val4-Leu5-) (1) and cyclo(-D-Trp1-D-Glu2-Ala3-D-alloIle4-Leu5-) (2) were prepared and tested for inhibitory activity against [125I]endothelin (ET-1) binding to protein ETA receptors. The DDLDL chirality sequence of the natural products appeared to be critical for inhibitory activity because conversion of either D-Trp or D-Glu (or both) in 1 to the corresponding L-isomer(s) abolished this property. Systematic modifications at each position of the natural products clarified the structure-activity relationships and led to highly potent and selective ETA receptor antagonists. Most replacements of D-Trp1 and Leu5 with other amino acids caused a significant loss of inhibitory activity. In contrast, replacement of D-Glu2 with D-Asp2 enhanced the activity. With regard to the Ala3 position, all analogues with imino acids, independent of being cyclic or acyclic, showed higher affinities than did the amino acid analogues. In addition, most replacements with amino acids, which had various functional groups in their side chains, did not significantly modify ETA binding affinity. The D-Val4/D-alloIle4 position was very important for inhibitory activity, and a beta-position branched D-amino acid or a D-heteroarylglycine was preferable at this position. Among synthesized cyclic pentapeptides, compound 36 (BQ-518) was the most potent ETA receptor antagonist, with a pA2 of 8.1 against ET-1-induced vasoconstriction in isolated porcine coronary arteries. This compound also showed the greatest selectivity between ETA and ETB receptors (IC50 for human ETA = 1.2 nM, IC50 for human ETB = 55 microM). In contrast, compound 8 (BQ-123) is a highly soluble, potent, and selective ETA receptor antagonist (pA2 = 7.4, IC50 for human ETA = 8.3 nM, IC50 for human ETB = 61 microM). The sodium salt of 8 is practically freely soluble in saline. These compounds are useful tools for not only in vitro but also in vivo pharmacological studies.

Amino Acid Sequence↗
PubMed1995

Prediction of the coding sequences of unidentified human genes. IV. The coding sequences of 40 new genes (KIAA0121-KIAA0160) deduced by analysis of cDNA clones from human cell line KG-1.

In this series of projects regarding the accumulation of sequence information of unidentified human genes, we newly deduced the sequences of 40 full-length cDNA clones of human cell line KG-1, and predicted the coding sequences of the corresponding genes, named KIAA0121 to 0160. The results of a computer search of public databases indicated that the sequences of 13 genes were unrelated to any reported genes, while the remaining 27 genes carried sequences which showed some similarities to known genes. Obvious unique sequences noted were as follows. A stretch of triplet repeats was contained in each of three genes: These were GAG(Glu) in KIAA0122 and KIAA0147, and TCC(Ser) in KIAA0150. A stretch of 10 amino acid-residues was repeated 21 times in KIAA0139, and a homologous sequence of 76-78 nucleotides was found repeated 6 times in the untranslated region of KIAA0125. Northern hybridization analysis demonstrated that 13 genes were expressed in a cell- or tissue-specific manner. Although a vast number of expressed sequence tags (ESTs) have been registered for comprehensive analysis of cDNA clones, our sequence data indicated that their distribution is very unbalanced: e.g. while no EST hit 7 genes, 85 ESTs fell in a single gene.

Amino Acid Sequence↗
PubMed1995

c-Myb repression of c-erbB-2 transcription by direct binding to the c-erbB-2 promoter.

The c-myb proto-oncogene product (c-Myb) is a transcriptional activator that can bind to the specific DNA sequences. Although c-Myb also represses an artificial promoter containing the Myb binding sites, natural target genes transcriptionally repressed by c-Myb have not been identified. We have found that the human c-erbB-2 promoter activity is repressed by c-Myb or B-Myb in a chloramphenicol acetyltransferase co-transfection assay. Domain analyses of c-Myb suggested that Myb represses the c-erbB-2 promoter activity by competing with positive regulators of the c-erbB-2 promoter. In in vitro transcription assays, Myb proteins containing only the DNA binding domain could repress c-erbB-2 promoter activity. Two Myb binding sites in the c-erbB-2 promoter were critical for transcriptional repression by c-Myb. One of the two Myb binding sites overlaps the TATA box, and DNase I footprint analyses indicated that c-Myb can compete with TFIID. These results suggest that Myb-induced trans-repression of the c-erbB-2 promoter partly involves competition between Myb and TFIID.

Base Sequence↗
PubMed1995

Prediction of the coding sequences of unidentified human genes. III. The coding sequences of 40 new genes (KIAA0081-KIAA0120) deduced by analysis of cDNA clones from human cell line KG-1.

We isolated full-length cDNA clones from size-fractionated cDNA libraries of human immature myeloid cell line KG-1, and the coding sequences of 40 genes were newly predicted. A computer search of the GenBank/EMBL databases indicated that the sequences of 14 genes were unrelated to any reported genes, while the remaining 26 genes carried some sequences with similarities to known genes. Significant transmembrane domains were identified in 17 genes, and protein motifs that matched those in the PROSITE motif database were identified in 11 genes. Northern hybridization analysis with 18 different cells and tissues demonstrated that 10 genes were apparently expressed in a cell-specific or tissue-specific manner. Among the genes predicted, half were isolated from the medium-sized cDNA library and the other half from the small-sized cDNA library, and their average sizes were 4 kb and 1.4 kb, respectively. As judged by Northern hybridization profiles, small-sized cDNAs appeared to be expressed more ubiquitously and abundantly in various tissues, compared with that of medium-sized cDNAs.

Cell Line↗
PubMed1995

A comparison of ventilation components in young and elderly men during exercise.

To elucidate the influence of age on ventilation components during exercise, we investigated the change in fractional contribution of abdomen or thorax during exercise in 12 elderly (71.9 +/- 5.3, mean +/- SD years) and 12 young (25.0 +/- 4.9 years) normal male subjects using respiratory-inductive plethysmography. At rest, abdominal/thoracic contribution was not different between elderly and young. During exercise, abdominal contribution to total ventilation was decreased in the young compared to that at rest (rest: 53.6 +/- 2.9% vs exercise: 50.4 +/- 1.9-48.9 +/- 1.8%; p < .01), but significantly increased in the elderly (rest: 53.9 +/- 1.8% vs exercise: 57.3 +/- 1.7-59.8 +/- 2.0%; p < .01). Only in the elderly, respiratory frequency was increased during exercise compared to that at rest (rest: 20.1 +/- 0.8 [/min] vs exercise; 25.6 +/- 1.5-27.8 +/- 1.6 [/min]; p < .05). The breathing pattern in the elderly during exercise was partly simulated in the young by reducing thoracic compliance using chest strapping. This study demonstrates the greater participation of diaphragmatic motion together with rapid shallow breathing during lower graded exercise in the elderly as compared with the young. This ventilatory pattern during exercise may result from a stiffening of the thorax with advancing age.

Abdomen↗
PubMed1995

Endoscope-assisted rib cartilage harvesting.

The seventh and eighth costal cartilages were harvested through a small 1.5 to 2 cm skin incision made in the midinframammary fold in female patients and the inferior border of the seventh coastal cartilage in male patients using an endoscope (total, 5 patients). The lateral half of the costal cartilage is dissected subperichondrially under direct visualization through the access incision, and the residual half is dissected subperichondrially using an endoscope. The advantages of using an endoscope to harvest costal cartilage include a better remote access incision site and a reduced risk of perforations of the pleura and bleeding through endoscopically-magnified visualization. This technique is particularly useful when the patient is a woman.

Adolescent↗
PubMed1995

In vivo effects of endothelin A- and B-receptor antagonists in guinea pigs.

Endothelin (ET)-1, a novel 21-amino acid constrictor peptide, has been recently reported to have a potential pathophysiological role in asthma. We hypothesized that ET-1 might affect guinea pig lung via different ET receptor subtypes, i.e., ETA and ETB, in vivo. To test this hypothesis, we investigated the effects of ET-1 on airways in anesthetized, open-chest, mechanically ventilated [frequency (f) = 1 Hz; tidal volume (VT) = 9 ml/kg; positive end-expiratory pressure (PEEP) = 4 cmH2O] guinea pigs in the absence or the presence of ETA and ETB selective antagonists, i.e., BQ-123 and BQ-788, respectively. We affixed alveolar capsules to the lungs to measure alveolar pressure and calculated the elastance of lung (EL) and the resistance of lung (RL), tissue (Rti), and airway (R(aw)) under control conditions and after intravenous administration of ET-1 (10(-8) mol/kg). ET-1 induced a concentration-dependent increase in RL, Rti, R(aw), and EL.BQ-123 (2 mg/kg) partially blocks delta RL and delta R(aw) during ET-1 induced constriction, while delta Rti and delta EL were not significantly affected. BQ-788 (2 mg/kg) significantly inhibited delta RL, delta Rti, delta R(aw), and delta EL during ET-1-induced constriction. The combination of BQ-123 and BQ-788 completely ablated the response to ET-1. These data suggest that both ET receptor subtypes, i.e., ETA and ETB, may have physiological roles in guinea pig airways in response to ET-1, a potential mediator of asthma.

Airway Resistance↗
PubMed1995

Dynamic elastance and tissue resistance of isolated liquid-filled rat lungs.

The effect of the surface forces of the alveolar air-liquid interface on the dynamic behavior of lung tissue was investigated in five isolated liquid-filled rat lungs. The lungs were subjected to 0.04-Hz sinusoidal oscillation (1.5-ml tidal volume) at lung volume (VL) levels ranging from volume at zero pressure (V0) + 4 ml to V0 + 10 ml. Oscillations were performed at each VL after inflation of the lungs from V0. Alveolar pressure (PA) was measured with an alveolar capsule attached to the visceral pleura. Dynamic elastance (Edyn), tissue resistance (Rti), and hysteresivity [eta = Rti omega/Edyn, where omega is angular frequency (2 pi x frequency)] were computed from PA and VL changes. Edyn was 59.6 +/- 4.3 Pa/ml at V0 + 4 ml and varied little up to V0 + 7 ml. Thereafter, Edyn increased markedly with VL, reaching 102 +/- 16 Pa/ml at V0 + 10 ml. No significant difference was found between elastance computed from PA and that computed from pressure recorded at the airway opening. Rti was 35.2 +/- 3.6 Pa.s.ml-1 and exhibited a VL dependence similar to that of Edyn. As a result, eta was 0.16 and did not vary significantly in the explored VL range. We conclude that PA can be reliably measured in the liquid-filled lung by means of alveolar capsules. In the liquid-filled lung, Edyn was smaller than and eta was similar to values reported for air-filled lungs. Hence, surface tension accounts for a considerable part of elastance and Rti of the air-filled lung within the volume range of normal breathing.

Animals↗