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Biomedical subjects

H Kai

Publications and source records attributed to H Kai.

At least 109 records · Page 6Linked to original sources
PubMed1992

The influence of neuraminidase treatment on tracheal smooth muscle contraction.

To examine the role of sialic acid in the respiratory tract, the influence of neuraminidase from Clostridium perfringens was investigated on contractions of isolated guinea-pig and rat trachea and on histamine release from guinea-pig lung tissue. Treatment with 2.0 units/ml of neuraminidase at 37 degrees C and pH 7.4 for 30 min caused an approximately 60% removal of total N-acetylneuraminic acid, a representative sialic acid, from muscle from guinea-pig and rat trachea. Neuraminidase concentration dependently induced histamine release from guinea-pig chopped lung tissue, but has no effect on contractions produced by acetylcholine, histamine and 5-hydroxytryptamine. Pretreatment with 2.0 units/ml of neuraminidase inhibited the contraction induced by antigen (ovalbumin) or compound 48/80. These findings suggest, at least in part, that sialic acids sensitive to neuraminidase are involved in the regulation of histamine release but not tracheal contraction.

Acetylcholine↗
PubMed1992

Both beta 1- and beta 2-adrenoceptors are involved in mediating phosphatidylcholine secretion in rat type II pneumocyte cultures.

A primary culture of rat type II pneumocytes was used for the pharmacological and functional characterization of beta-adrenoceptor subtypes. The beta-adrenoceptor agonists, isoprenaline, dobutamine and procaterol concentration dependently increased the secretion of phosphatidylcholine. These effects were attenuated by propranolol. The effect of dobutamine was attenuated by atenolol, and that of procaterol by ICI 118,551. Isoprenaline-induced secretion was attenuated by the combination of the two blockers but not by each one alone. In conclusion, both beta 1- and beta 2-adrenoceptor subtypes mediate phosphatidylcholine secretion in rat type II pneumocytes.

Adrenergic beta-Agonists↗
PubMed1992

Histological examination of surface repair tissue after successful osteotomy for osteoarthritis of the hip joint.

In this study biopsy specimens of the surface repair tissue from the weightbearing area of the hip joint were collected from 15 patients who had undergone successful valgus osteotomy, and these were examined histologically. In 6 of the 15 patients the specimens stained strongly with safranin-O in all three layers of the matrix. However, the repair tissue from another 6 patients showed strong staining only in the intermediate and deep layers, while that from 2 patients stained only in the deep layer. Specimens from 5 patients were stained for S-100 protein and positive cells were detected in all cases, demonstrating that the cells in the repair tissue were chondrocytes. However, there was no tide mark in the repair tissue and the arrangement of the cells differed from that in normal cartilage. Discontinuity of the subchondral bone was also noted. These findings make it likely that the repair tissue was of bone marrow origin.

Adult↗
PubMed1992

Aortic valve prolapse with aortic regurgitation assessed by Doppler color-flow echocardiography.

The incidence of and the Doppler color-flow echocardiographic characteristics of aortic valve prolapse with nonrheumatic aortic regurgitation were examined. Aortic valve prolapse was observed in 21 of 243 patients (15 men and 6 women) with aortic regurgitation as detected by Doppler color-flow echocardiography (rheumatic, 112; nonrheumatic, 131) in 1247 consecutive patients. Patients with aortic valve prolapse included three patients with essential hypertension and one with annuloaortic ectasia. The remaining 17 patients (7% of those with aortic regurgitation) had no other associated cardiovascular disease (idiopathic aortic valve prolapse). Prolapse of the mitral or the tricuspid valve or both was associated with aortic valve prolapse in seven patients. Aortic regurgitation jet was markedly deviated from the axis of left ventricular outflow tract toward the anterior mitral leaflet or the interventricular septum in 17 of 21 (81%) patients with aortic valve prolapse, whereas 28 of 110 (25%) patients with nonrheumatic aortic regurgitation without prolapse and 17 of 112 (15%) patients with rheumatic aortic regurgitation without prolapse showed the deviation of regurgitant jet (p < 0.001). In conclusion, idiopathic aortic valve prolapse is one of the significant causes of aortic regurgitation, and a marked deviation of regurgitant jet is a characteristic Doppler color-flow echocardiographic finding of aortic regurgitation that results from aortic valve prolapse.

Adolescent↗
PubMed1992

Preservation of endothelium-dependent vasodilation in the spastic segment of the human epicardial coronary artery by substance P.

The objective of this study was to determine if endothelium-dependent vasodilation is preserved in the spastic segment of the epicardial coronary artery. Segmental responses of the coronary artery to substance P were examined by the use of a quantitative angiographic technique in 21 patients with variant angina. Coronary diameter at the basal state did not differ between the spastic and the nonspastic segments (2.3 +/- 0.2 mm, 2.3 +/- 0.4 mm, p greater than 0.05). Changes in coronary diameter in response to substance P did not differ between segments with ergonovine-induced spasm and nonspastic segments. Maximal dilation averaged 27.1 +/- 9.5% in the spastic segment and 24.4 +/- 9.6% in the nonspastic segment (expressed as a percent increase over the value before drug administration). It appears that both the potential of the endothelium to release endothelium-dependent relaxing factor and the dilating response of the smooth muscle to endothelium-dependent relaxing factor are preserved, even in the spastic segment.

Angina Pectoris, Variant↗
PubMed1992

Clinical symptoms of open lock position of the condyle. Relation to anterior dislocation of the temporomandibular joint.

Nine cases of open lock position of the condyle of the temporomandibular joint (TMJ) are reported. In two patients recurrent dislocation of the TMJ was diagnosed clinically, and four had previous episodes of anterior dislocation. An arthrotomographic examination revealed that the condyles of the affected TMJs were located anterior to the anterior bands of the disks at an open-mouth position. An arthrographic fluoroscopic examination showed that the anterior bands mechanically obstructed the anteriorly displaced condyles from posterior movement into the articular fossae to various degrees at open-mouth position. One cause of anterior dislocation of the TMJ is thought to be fixation of the condyle in the open lock position resulting from a disturbance of a neuromuscular mechanism. In the two patients with dislocation, occlusal treatment eliminated muscular symptoms and the dislocations completely disappeared.

Adult↗
PubMed1992

Removal of extracellular Mg2+ suppresses sulfation of glycoconjugates secreted from rabbit trachea in culture.

The influences of extracellular Ca2+ and Mg2+ concentrations on the basal secretion of glycoconjugates from rabbit trachea in organ culture were examined. Over 80% of the 35S-labeled and [3H]glucosamine-labeled glycoconjugates secreted by the trachea were digested upon incubation with chondroitinase ABC. The basal secretion did not occur in the medium at 4 degrees C, indicating an energy-dependent process. The basal secretion at 37 degrees C of 35S-labeled glycoconjugates was prominently suppressed in Mg(2+)-free Tyrode solution but not in Ca(2+)-free Tyrode solution containing ethyleneglycol bis(2-aminoethylether)tetraacetic acid (EGTA). In contrast, the basal secretion of [3H]glucosamine-labeled glycoconjugates was not affected by the Mg2+ concentration in the medium. The results suggest that extracellular Mg2+ largely contributes to sulfation of glycoconjugates basally secreted from rabbit trachea.

Animals↗
PubMed1992

Radiological evaluation on allograft reconstruction of the acetabulum combined with supporting device in revision total hip replacement.

We reviewed the radiographs of 25 hips of 20 patients who had received revisions of the acetabular components of total hip replacement supplemented by allograft for bone defects. Bone defects in 20 hips (80%) were classified into type D (cranio-central defect) according to Itoman's classification. In eight, sockets were installed directly on the allografts (group A). A metallic supporting device was used for reinforcing the grafts in 17 hips (group B). The position of the acetabular socket was measured on a radiograph, taken immediately after revision surgery and again at the latest follow-up. Using a MEM template, cranial and central migrations were determined. Mean cranial migration in hips of group A was 3.6 mm. Group B was 0.2 mm. Maintenance of thickness of the allografts was 60.6% in the cranial region and 75% in the central in group A. In the hips of group B, however, almost 100% of the initial thickness was maintained cranially and centrally. Allograft reconstruction of acetabular bone defect in revision total hip replacement is a beneficial procedure. The remaining pelvic bone is usually in poor condition, therefore, it is necessary to ensure primary fixation by the metallic supporting device.

Acetabulum↗
PubMed1991

Stimulation of pulmonary surfactant secretion by activating neutrophils in rat type II pneumocytes culture.

The influence of activating neutrophils on the secretion of phosphatidylcholine (PC), the predominant component of pulmonary surfactant, was examined using primary culture of rat type II pneumocytes. Simultaneous addition of neutrophils and opsonized zymosan, but not neutrophils or opsonized zymosan alone, to type II pneumocytes caused a significant increase in PC secretion without affecting the release of lactate dehydrogenase, a marker of cytotoxicity. The increase in PC secretion was dependent on the number of activating neutrophils. In addition, pretreatment of culture with the combination of superoxide dismutase and catalase inhibited the increase in PC secretion. These findings indicate that activating neutrophils stimulate the secretion of pulmonary surfactant and that the stimulation is mediated by oxygen radicals.

Animals↗
PubMed1990

Pulmonary surfactant secretion in the type II pneumocytes in inflamed condition.

Basal PC secretion in the type II pneumocytes from bronchitic rats was the same as that in the type II pneumocytes from normal rats. Neutrophils activated by opsonized zymosan or PMA, stimulated PC secretion in type II pneumocytes without causing any cell damage. The stimulation required close accession or attachment of neutrophils and type II pneumocytes and was not affected by the pretreatment with either SOD, catalase, AA861 or alpha 1-antitrypsin.

Animals↗
PubMed1990

Anti-allergic effect of N-acetylneuraminic acid in guinea-pigs.

The in-vivo anti-allergic effect of N-acetylneuraminic acid (NANA) in guinea-pigs passively sensitized with anti-ovalbumin rabbit serum has been studied. NANA (20 mg kg-1 i.v.) inhibited bronchial anaphylaxis and the release of histamine into bronchoalveolar lavage fluid. NANA dose-dependently inhibited heterologous passive cutaneous anaphylaxis and haemorrhaging in the passive Arthus reaction. However, it did not inhibit the release of histamine from sensitized minced lung tissue.

Anaphylaxis↗
PubMed1990

[Changes in lipid peroxides content and antioxidant enzyme activities on airway surface in SO2-induced bronchitic rats].

The changes in lipid peroxides (LP) content and antioxidant enzyme activities were investigated on airway surface during the aggravating process of bronchitis induced by SO2 exposure in rats. LP content in broncho-alveolar lavage fluid (BALF) has gradually increased from 3 weeks after starting of SO2 exposure. Whereas, the activities of antioxidant enzymes, superoxide dismutase and glutathione peroxidase, increased at 1 week and then gradually reduced from 3 weeks. The ratio of LP to each antioxidant enzyme activity in BALF of the exposed rats was higher than that of normal rats. Morphological changes of the lung, a decrease of PaO2 and an increase of PaCO2 of blood depended on the increase of LP on airway surface. These findings indicate that LP may be involved in the development of bronchitis.

Animals↗
PubMed1990

Influence of corticosterone on tracheal mucociliary transport in pigeons.

The effects of corticosteroids on tracheal mucociliary transport (MCT) were examined in pigeons. Intramuscular administration of corticosterone had no effect at 1.0 mg/kg, while at a larger dose of 5.0 mg/kg, it slightly, but significantly increased the MCT rate. Metyrapone significantly decreased the MCT rate, and the inhibitory action was blocked by 1.0 mg/kg corticosterone. The present study suggested that corticosteroids modulated the mucociliary clearance, especially under some diseases associated with a decreased level of endogenous corticosteroids.

Animals↗
PubMed1989

Endothelin-induced Ca-independent contraction of the porcine coronary artery.

Front surface fluorometry and porcine coronary arterial strips loaded with fura-2 were used to investigate the effect of endothelin on cytosolic Ca concentrations, [Ca]i, and on contractile force, the objective being to elucidate the mechanism of action. Both in the presence and absence of extracellular Ca, endothelin induced rapid and dose-dependent increases in [Ca]i and in contraction. When caffeine-sensitive and histamine-sensitive intracellular Ca stores were depleted, in Ca-free medium, a transient contraction but no increase in [Ca]i followed the subsequent application of endothelin. This Ca-independent component was largely inhibited by the relative protein kinase C inhibitor, H-7, but not inhibited by W-7, calmodulin antagonist. This component is probably linked to activation of protein kinase C.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1989

Endothelin-sensitive intracellular Ca2+ store overlaps with caffeine-sensitive one in rat aortic smooth muscle cells in primary cultures.

We made use of quin2 microfluorometry to determine the effects of endothelin (ET) on cytosolic free Ca2+ concentrations [Ca2+]i) in rat aortic smooth muscle cells in primary culture. In Ca2+-containing medium, ET induced a rapid and sustained elevation of [Ca2+]i. In the latter component, in particular, the elevation of [Ca2+]i was inhibited by diltiazem. In Ca2+-free medium, ET induced a rapid and transient [Ca2+]i elevation, which was not inhibited by diltiazem. When the caffeine-sensitive intracellular Ca2+ store was practically depleted by repeated treatment with caffeine in Ca2+-free media, ET did not elevate [Ca2+]i. Thus, it was suggested that ET induces [Ca2+]i elevation not only by extracellular Ca2+-dependent, mechanisms but also by releasing Ca2+ from the intracellular store, and that the ET-sensitive Ca2+ store may overlap with the caffeine-sensitive one, in cultured vascular smooth muscle cells.

Aminoquinolines↗
PubMed1989

Increased production and/or secretion of pulmonary surfactant in rats by long term sulfur dioxide exposure.

Influence of long term SO2 exposure on the pulmonary surfactant in rats was studied by means of chemical analysis and microscopic verification. At a time after termination of the exposure period, the general symptom in rats was similar to that of bronchitis. The content of disaturated phosphatidylcholine, a main functional component of the pulmonary surfactant, significantly increased not only in broncho-alveolar lavage fluid but also in pulmonary microsomal fraction by long term SO2 exposure. Microscopic verification of alveolar type II cells from the bronchitic rats demonstrated the development of rough surface endoplasmic reticulums and an increase of the number of osmiophillic bodies. The results suggest that pulmonary surfactant production and/or secretion are activated in rats with bronchitis caused by long term SO2 exposure.

Animals↗
PubMed1989

Protective effect of surface-active phospholipids against the acid-inducing inhibition of the tracheal mucociliary transport.

Little is known about the physiological role of surface active phospholipids (SAP) in the central respiratory tract. In the present study, the effect of SAP on acid-inducing inhibition of particle transport by the tracheal mucociliary function was investigated in unanesthetized pigeons. SAP and acids were directly nebulized to the surface of the trachea. The composition of SAP was based on that of the pulmonary surfactant. The experiment was carried out under application of acetylcholine providing a constant mucociliary transport. SAP significantly diminished HCl- and H2SO4-inducing inhibitions of the mucociliary transport. Benzalkonium chloride also reduced the inhibition. The results suggest that SAP may be a protecting factor of the mucociliary clearance and that SAP may be connected with hydrophobicity not only of the alveolar surface but of the tracheal epithelium.

1,2-Dipalmitoylphosphatidylcholine↗