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Biomedical subjects

T Sakuma

Publications and source records attributed to T Sakuma.

At least 91 records · Page 5Linked to original sources
PubMed1997

Appositional angle closure in eyes with narrow angles: comparison between the fellow eyes of acute angle-closure glaucoma and normotensive cases.

PURPOSE: To identify topologic features of eyes with acute primary angle-closure glaucoma before an attack as compared with those features in normotensive cases, assuming that untreated fellow eyes of acute primary angle-closure glaucoma are candidates for an acute attack. METHODS: A total of 50 eyes (12 fellow eyes of acute primary angle-closure glaucoma and 38 normotensive cases with a closure-possible narrow angle) were prospectively examined by ultrasound biomicroscopy under dark-room conditions. All eyes were examined before surgical or laser intervention and had normal pupillary reaction without any topical drugs. Four predetermined angle locations per eye were examined. Parameters regarding the chamber angle configuration were measured and compared between the two groups. RESULTS: Appositional angle closures were observed in 27 locations in fellow eyes and in 48 locations in normotensive eyes with a closure-possible narrow angle. The incidence was statistically different between the two groups (69.2% in the fellow eyes and 48% in the normotensive eyes). Appositional angle closures beginning at the entrance of the angle were more frequently detected in the fellow eye group. The distance between the iris root and the bottom of the angle was significantly different between the two groups. CONCLUSION: The fellow eyes of acute primary angle-closure glaucoma have different topologic features from normotensive narrow-angled eyes and a higher incidence of appositional closure that may predispose these eyes to an imminent acute attack.

Acute Disease↗
PubMed1996

Purification and cDNA cloning of porcine brain GDP-L-Fuc:N-acetyl-beta-D-glucosaminide alpha1-->6fucosyltransferase.

GDP-L-Fuc:N-acetyl-beta-D-glucosaminide alpha1-->6fucosyltransferase (alpha1-6FucT; EC 2.4.1.68), which catalyzes the transfer of fucose from GDP-Fuc to N-linked type complex glycopeptides, was purified from a Triton X-100 extract of porcine brain microsomes. The purification procedures included sequential affinity chromatographies on GlcNAcbeta1-2Manalpha1-6(GlcNAcbeta1-2Manalpha1- 2)Manbeta1-4GlcNAcbet a1-4GlcNAc-Asn-Sepharose 4B and synthetic GDP-hexanolamine-Sepharose 4B columns. The enzyme was recovered in a 12% final yield with a 440, 000-fold increase in specific activity. SDS-polyacrylamide gel electrophoresis of the purified enzyme gave a major band corresponding to an apparent molecular mass of 58 kDa. The alpha1-6FucT has 575 amino acids and no putative N-glycosylation sites. The cDNA was cloned in to pSVK3 and was then transiently transfected into COS-1 cells. alpha1-6FucT activity was found to be high in the transfected cells, as compared with non- or mock-transfected cells. Northern blotting analyses of rat adult tissues showed that alpha1-6FucT was highly expressed in brain. No sequence homology was found with other previously cloned fucosyltransferases, but the enzyme appears to be a type II transmembrane protein like the other glycosyltransferases.

Amino Acid Sequence↗
PubMed1996

A 100-kDa protein tyrosine phosphorylation is concurrent with beta 1 integrin-mediated morphological differentiation in neuroblastoma and small cell lung cancer cells.

IMR32, a neuroblastoma cell line, and CADO LC6, a small cell lung cancer (SCLC) cell line, extended neurite-like processes when cultured on fibronectin (FN)-coated surfaces or cultured in a serum-free medium. Monoclonal antibodies against the integrin beta 1 subunit inhibited this process formation, suggesting that their morphological change is initiated by beta 1 integrin-dependent signal transduction to the cell interior. Anti-phosphorylation level of a 100-kDa protein, but not 125-kDa focal adhesion kindase, correlated well with the morphological change in both cell lines. This 100-kDa protein phosphorylation did not accompany FN-induced morphological changes in NIH 3T3 fibroblasts or A549 adenocarcinoma cells. These findings suggest that neuroblastoma and SCLC may share beta 1 integrin-mediated signaling events distinct from nonneuronal cells.

Adenocarcinoma↗
PubMed1996

Intracranial calcification on gradient-echo phase image: depiction of diamagnetic susceptibility.

PURPOSE: To differentiate calcification from hemorrhage on the basis of susceptibility at magnetic resonance imaging. MATERIALS AND METHODS: Gradient-recalled echo (GRE) phase imaging was performed at 1.5 T in 101 calcified areas (15 in the basal ganglia, 86 out of the basal ganglia) and 39 uncalcified locations (13 choroid plexus and pineal glands, 26 old hemorrhages). Experiments with a small lead particle and a numerical simulation were also performed. RESULTS: The majority of calcifications outside the basal ganglia (n = 63) revealed a phase shift that represents diamagnetic susceptibility and was similar to the phase shift in the lead particle and to the calculated phase shift for a diamagnetic sphere. All hemorrhages and almost all calcified basal ganglia revealed a phase shift that represents paramagnetic susceptibility. All uncalcified choroid plexus and pineal glands revealed no obvious phase shift. Any location without calcification did not reveal the diamagnetic phase shift. CONCLUSION: GRE phase imaging differentiated paramagnetic from diamagnetic susceptibility, which was specific for calcification.

Aged↗
PubMed1996

Preservation of alveolar epithelial fluid transport mechanisms in rewarmed human lung after severe hypothermia.

Although hypothermia abolishes alveolar fluid clearance in the in situ goat lung and in the ex vivo human lung, it is unknown whether alveolar fluid clearance resumes in lungs that are rewarmed after severe hypothermia. An isosmolar albumin solution was instilled into resected human lungs that were rewarmed to 37 degrees C after hypothermia (7 +/- 3 degrees C), and then alveolar fluid clearance was measured by the concentration of albumin in the alveolar fluid sample after 4 h. In control experiments in lungs that had not been cooled and rewarmed, alveolar fluid clearance was 11 +/- 2% over 4 h. In separate experiments, hypothermia completely abolished alveolar fluid clearance. However, alveolar fluid clearance resumed to a normal level of 12 +/- 1% over 4 h in the lungs that were rewarmed after hypothermia. Amiloride decreased alveolar fluid clearance by 47% in the rewarmed lungs. Terbutaline increased alveolar fluid clearance by nearly 300% in 2-h experiments in the rewarmed lungs (P < 0.05). The results of this study indicate that alveolar sodium-channel transport mechanisms are preserved in resected human lungs that are exposed to rewarming after hypothermia.

Aged↗
PubMed1996

Comparison of surface antigens on eosinophils from patients with eosinophilia.

Recent studies have suggested that there may be heterogeneity among human eosinophils. To study this further, surface antigens on blood eosinophils from patients with eosinophilia (23 bronchial asthma, 6 eosinophilic pneumonia, 1 Kimura's disease and 1 adult T-cell leukemia) and from 8 control subjects were examined using a new direct method for fluorescence detection of eosinophils. HLA-DR+ and CD4+ eosinophil counts were higher in patients with bronchial asthma and adult T-cell leukemia (ATL) than in patients from other groups and in control subjects. CD11b+ eosinophil counts in Kimura's disease and ATL were smaller than those in the other groups. CD45RO+ eosinophil counts in bronchial asthma and eosinophilic pneumonia were significantly higher (p < 0.05) compared with Kimura's disease, ATL and control subjects. CD44+ eosinophil counts in eosinophilic pneumonia were significantly higher (p < 0.05) compared with the other groups and control subjects. These results suggest the existence of functional heterogeneity in the different eosinophilic diseases, with eosinophils in bronchial asthma and eosinophilic pneumonia being more highly activated in migration, activation and immunoregulation. On the other hand, eosinophils in Kimura's disease and ATL might be functionally down-regulated. This heterogeneity of eosinophils may reflect differences in the pathogenesis of various eosinophilic diseases.

Adolescent↗
PubMed1996

Inhibitory effects of catechol derivatives on hydrophilic free radical initiator-induced hemolysis and their interaction with hemoglobin.

The effects of pyrocatechol and its monosubstituents on the hemolysis of bovine erythrocytes induced by the hydrophilic free radical initiator, 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH), were investigated. Relatively hydrophilic derivatives such as the 4-COO- substituent (protocatechuic acid), which are almost completely ionized at physiological pH, have a more inhibitory effect than the more hydrophobic derivatives such as the 4-C(CH3)3 substituent. In the presence of relatively low concentrations of the latter derivatives, the onset of hemolysis was retarded, but the hemolysis then proceeded more rapidly and the time, at which almost complete hemolysis occurred, was almost the same as that in their absence. Regression analysis on the relationships between the inhibitory effects of the derivatives and their redox potentials and hydrophobic parameters revealed that the inhibitory activity of the catechol derivatives on AAPH-induced hemolysis was controlled by low hydrophobicity as well as electron donor activity. In the presence of relatively hydrophobic catechol derivatives, oxidation of hemoglobin was observed. These findings suggest that interaction of these derivatives with hemoglobin after their penetration erythrocytes reduced the scavenging activity against free radicals. Their interaction with membrane or cytoplasmic components may cause the increased hemolysis rate after the onset of hemolysis at relatively low concentrations.

Amidines↗
PubMed1996

Sleep oxygen desaturation in late sequelae of pulmonary tuberculosis.

Thirty-eight patients with late sequelae of pulmonary tuberculosis (TB seq.) were studied to clarify the characteristics of sleep desaturation in comparison with 40 patients with chronic obstructive pulmonary disease (COPD). While awake, the TB seq. group had a lower % VC and a higher PaCO2. In both groups, the sleep lowest SaO2 was positively correlated with the awake SaO2. The regression line between the sleep lowest SaO2 and the awake baseline SaO2 in the TB seq. group was located below that in the COPD group. Awake PaCO2 was negatively related to the sleep lowest SaO2 only in the TB seq. group. These results indicate that the sleep lowest SaO2 values were lower in TB seq. than in COPD patients with the same levels of SaO2 while awake. Sleep studies are necessary to reveal the indication for nocturnal oxygen therapy in TB seq. patients, especially when they are hypercapnic in spite of their good awake oxygenation.

Aged↗
PubMed1996

[Reconstruction after wide resection of the chest wall: application of plates as rigid prosthetic materials].

Wide resection of the chest wall requires reconstruction with rigid prosthetic material to protect the thoracic organs and to avoid flail chest. We tried to use three kinds of plates for chest wall reconstruction in 4 cases: acrylic plate for 1, ultra-high-molecular-weight polyethylene (UHMWP) plate for 1 and methyl metacrylic resin (MMR) plate for 2. Marlex mesh was utilized to strengthen the rebuilt chest wall sandwiching rigid prosthesis in UHMWP plate and MMR plate. Except for somewhat local accumulation of serous fluid in two cases of acrylic plate and MMR plate, postoperative courses were uneventful in all cases. Acrylic plate which was used for patient with metastatic sternal tumor was easily damaged by heat. UHMWP plate which was used for patient with large benign sternal tumor was expensive and took a long time to make. On the other hand, MMR plates which were used for two patients with malignant lateral chest wall tumor were easy to handle on the spot and not expensive. MMR plate sandwiched by Marlex mesh seems to be more suitable and available for chest wall reconstruction.

Adolescent↗
PubMed1996

[Successful aorto-coronary bypass grafting and concomitant left ventricular myotomy-myectomy in a patient with coronary artery disease associated with hypertrophic obstructive cardiomyopathy].

A 65-year-old man complained chest oppression at rest and dizziness. Echocardiography showed subaortic stenosis with outflow gradient of 100 mmHg, although interventricular septal thickness was only 12 mm and left ventricular posterior wall thickness was 11 mm, and mild mitral regurgitation. Selective coronary angiography demonstrated 90% stenosis in left main truncus, 50% stenosis in first diagonal branch, and hypoplastic right coronary artery. Emergent coronary artery revasculization concomitant with left ventricular myotomy myectomy was performed. Immediately after weaning off the cardiopulmonary pump, IABP was employed for cardiac assistance, because of residual left ventricular outflow pressure gradient, which was provoked by cathecholamine and amyl nitrite. He was discharged in 1 month in NYHA class I. Echocardiography 3 months after operation showed no residual outflow pressure gradient, no systolic anterior motion of mitral anterior leaflet, and mild approximately mitral regurgitation. Careful operative management, including myocardial protection and avoiding perforation of ventricular septum and postoperative medical care are mandatory to this group of patients. This case is the first successful coronary artery bypass grafting and concomitant left ventricular myotomy-myectomy reported in Japan.

Aged↗
PubMed1996

Relaxation of human isolated pulmonary arteries by amrinone.

Amrinone, a selective phosphodiesterase III inhibitor, has been developed as a nonglycoside, noncatecholamine agent with positive inotropic effect. In this study, we examined the effect of amrinone on human pulmonary arterial strips in vitro to understand its action on human pulmonary circulation. Amrinone (10(-5)-10(-3) g/ml) caused dose-dependent relaxation of human pulmonary arterial strips precontracted with 60 mM KCl. Preincubation with either meclofenamate (3.1 microM), a cyclooxygenase inhibitor, or L-N(G)-nitroarginine (100 microM), a competitive inhibitor of EDRF/NO, failed to inhibit amrinone-induced pulmonary vasodilation. The cyclic AMP (cAMP) levels in the supernatant of the lung vessel homogenates increased after incubation with amrinone (10(-3) g/ml). These findings indicate that amrinone causes vasodilation of human pulmonary artery in vitro, and suggest a possible role for cAMP in the mechanisms of amrinone-induced pulmonary vasodilation. Because it is suggested that amrinone has not only positive inotropic effect but also pulmonary vasodilative effect in human in this study, we speculate that amrinone could be an useful agent for the treatment of an increase in right heart afterload and consequent pulmonary hypertension and right heart failure after lung resection in human.

Adult↗
PubMed1996

[Compliance with long-term home oxygen therapy].

Long-term home oxygen therapy has been shown to benefit patients with hypoxemic chronic obstructive pulmonary disease. However, to obtain the expected maximal benefit it is important for the oxygen to be used correctly and for a sufficient length of time. We examined compliance with home oxygen therapy in patients with chronic obstructive pulmonary disease, pulmonary fibrosis, late sequelae of pulmonary tuberculosis, and pulmonary hypertension who used oxygen concentrations. Compliance was defined as the ratio of the amount of oxygen used to the amount prescribed. The average daily length of time the concentrator actually ran was measured from the concentrator meters. These were read every 6 months by an engineer from the company that installed the concentrator. Factors thought to affect compliance were studied. These factors included age, the degree of dyspnea, arterial blood gases, and pulmonary function. Weak positive correlations were found between compliance and age and between compliance and PaCO2. A weak negative correlation was observed between compliance and PaO2. Compliance in patients with chronic obstructive pulmonary disease was higher than in patients with pulmonary fibrosis or pulmonary hypertension. Among those given prescriptions for 24-hr oxygen therapy, compliant patients had more severe dyspnea on excertion than did noncompliant patients. These data suggest that the compliant patients had more severe gas exchange problems.

Aged↗
PubMed1996

[Effects of subacute hypoxia on alveolar epithelial ion transport in rats].

To study the effects of subacute hypoxia on alveolar epithelial ion transport, alveolar fluid clearance was measured in isolated fluid-filled rat lungs. After instillation of a solution containing about 5% bovine albumin, an increase in alveolar fluid clearance was measured over 2 hours. Alveolar fluid clearance was lower when rats were kept in hypoxic conditions (FiO2 = 0.1) for 48 hours. Neither 10(-5) M amiloride (a Na(+)-channel blocker) nor 10(-3) M ouabain (an inhibitor of Na(+)-K(+)-ATPase) inhibited fluid clearance in the hypoxia group, but they did in the normoxia group. These results indicate that subacute hypoxia may down-regulate both the Na(+)-channl and Na(+)-K(+)-ATPase, and thus decrease the absorption of excess alveolar fluid.

Animals↗
PubMed1996

[Effect of time in culture on modulation of Na(+)-K(+)-ATPase activity in rat alveolar type II cells].

To determine the effect of time in culture on epithelial cell function, we evaluated the modulation of Na(+)-K(+)-ATPase activity in rat alveolar type II cells in culture. Ouabain sensitivity testing revealed that the alpha-1 predominance in the enzyme's isoforms was maintained over the 120 hours in culture. Basal Na(+)-K(+)-ATPase activity in the whole cell homogenate did not differ significantly between cells cultured for 48 hours and those cultured for 120 hours. Terbutaline (10 mM) did not activate Na(+)-K(+)-ATPase in the cells cultured for 48 hours, but, it significantly increased the activity of this enzyme in the cells cultured for 120 hours cells cultured for 48 hours, produced intracellular cyclic AMP after exposure to 10 mM of terbutaline. These results indicate that the coupling between Na(+)-K(+)-ATPase and the beta-adrenergic pathway in alveolar type II cells can be influenced by the time in cell culture.

Adrenergic beta-Agonists↗
PubMed1996

[Long-term effect of a beta-adrenergic agonist on sodium uptake into cultured rat alveolar type II cells].

To evaluate the long-term effect of a beta-adrenergic agonist on Na(+)-channel function in cultured rat alveolar type II cells, we measured 22Na+ uptake into type II cells cultured in the presence and absence of 0.1 mM terbutaline for up to 5 days. Terbutaline did not influence the growth, morphology, or protein content of the cells. Terbutaline increased amiloride-inhibitable 22Na+ uptake into the cells at day 2 in culture, but there was no significant difference at day 5. Because amiloride-inhibitable 22Na+ uptake reflects Na(+)-channel function, these data indicate that terbutaline may transiently upregulate Na(+)-channel function. This study provides direct evidence of a long-term effect of a beta-adrenergic agonist on Na(+)-channel function in alveolar type II cells.

Adrenergic beta-Agonists↗
PubMed1996

[Role of Na(+)-glucose cotransport in fluid absorption across alveolar epithelium in isolated rat lungs].

To evaluate the role of Na(+)-glucose cotransport in fluid absorption across alveolar epithelial walls in isolated rat lungs, we measured the inhibitory effects of amiloride (a Na+ channel blocker) and phlorizin (a Na(+)-glucose cotrasport blocker) on the fluid absorption rate in fluid-filled lungs. Amiloride (10(-5)-10(-4) M) reduced alveolar fluid absorption by 30%. This value was similar to that obtained in the presence of 10(-3) M phlorizin. The coefficient of Na(+)-glucose cotransport was estimated to be 2.5. The strong correlation between Na+ escape and fluid absorption (r = 0.907) was not affected by phlorizin. These findings suggest that the impact of Na(+)-glucose cotransport was similar to that of Na+ transport alone, and that glucose molecules transported by Na(+)-glucose cotransport do not play an important role in alveolar fluid absorption across rat alveolar epithelium.

Absorption↗