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Y Okada

Publications and source records attributed to Y Okada.

At least 109 records · Page 6Linked to original sources
PubMed2001

Extra-anatomical bypass grafting for coarctation of the aorta associated with annuloaortic ectasia. Long-term outcome.

Two patients each with a rare combination of aortic coarctation and annuloaortic ectasia underwent successful single-stage repair in which the aortic root was reconstructed with a valved conduit, and an extra-anatomical bypass was made by grafting from the ascending to the abdominal aorta. Although the long-term outcome of such a long extra-anatomical bypass graft has not yet been established, the use of the graft for reducing the risk to coarctation-related complications during the early and late postoperative periods appears promising.

Adult↗
PubMed2001

Accumulation of latent transforming growth factor-beta binding protein-1 and TGF beta 1 in extracellular matrix of filtering bleb and of cultured human subconjunctival fibroblasts.

PURPOSE: To examine immunohistochemically whether extracellular matrix (ECM) of the filtering bleb and of cultured human subconjunctival fibroblasts contains latent TGF beta binding protein-1 (LTBP-1) and TGF beta. METHODS: An enucleated human eye that had undergone trabeculectomy and cultured human subconjunctival fibroblasts were processed for light microscopic immunohistochemistry. Antibodies against LTBP-1, collagen types, fibrillin-1 and TGF beta s were used. TGF beta 1 was located by detecting beta 1-latency associated peptide (LAP). RESULTS: LTBP-1, beta 1-LAP and fibrillin-1 were all located in the subepithelial ECM as well as in the basal epithelial cells of the conjunctiva over the filtering bleb. TGF beta 2 and beta 3 were immunolocated to epithelium and/or fibroblasts/keratocytes. ECM deposited in confluent fibroblast cultures was positive for beta 1-LAP, LTBP-1 and fibrillin-1, whereas sparse cells were negative. CONCLUSIONS: LTBP-1, beta 1-LAP and fibrillin-1 are co-localized to the ECM of the filtering bleb and of cultured conjunctival fibroblasts. Both conjunctival epithelium and fibroblasts are considered to be the source of TGF beta in healing bleb. ECM secreted by in vivo and in vitro subconjunctival fibroblasts may works as a scavenger or repository of TGF beta.

Carrier Proteins↗
PubMed2001

Surgical treatment for chronic pulmonary thromboembolism under cardiopulmonary bypass with selective cerebral perfusion.

The median sternotomy approach for the treatment of chronic pulmonary thromboembolism was recently improved by Daily, Jamieson, and coworkers who adopted it for use under cardiopulmonary bypass with intermittent circulatory arrest; however, we have sometimes found that the circulatory arrest time was too short to complete thromboendarterectomy. Therefore, we attempted to perform a selective cerebral perfusion technique to extend the endarterectomy time. Although we noted slight back-bleeding from the bronchial arteries, we were able to extend the endarterectomy time without causing any postoperative delirium. We conclude that the median sternotomy approach using cardiopulmonary bypass with selective cerebral perfusion may be the best option for extending the thromboendarterectomy time.

Aged↗
PubMed2001

Morphometric analysis, at electron microscope level, combined with hormone assay of nonfunctioning adrenocortical adenomas: comparison with aldosterone-producing adenomas.

We performed electron microscopic studies of eight nonfunctioning adrenocortical adenomas (NFA) and nine aldosterone-producing adenomas (APA) obtained from surgical specimens. A comparison of these two types of adenomas was conducted by morphometric analysis of random electron micrographs. The organelles measured included mitochondria (M), smooth-surfaced endoplasmic reticulum (SER), rough-surfaced endoplasmic reticulum (RER), lipid vacuoles (LV), and lysosomes (Ly). The content of steroid hormones, including 17-alpha hydroxyprogesterone (17-OHP), aldosterone (Ald), and other steroid hormones, was measured in adenoma tissue from six NFA and eight APA. The percentages of the areas of the organelles M, SER, and RER per total cell area in the NFA were significantly lower than those in the APA. The average content of Ald in adenoma tissues in APA was markedly higher than that in the NFA, while the mean content of 17-OHP in the NFA was significantly higher than that in APA. In conclusion, NFA are morphometrically characterized by a reduction in organelles such as M, SER, and RER, compared with findings in APA. From the quantitative analysis of steroid hormones, it was suggested that NFA produce more precursor substances with less hormone activity than APA and that steroidgenesis in NFA is shifted to a glucocorticoid pathway, as indicated by the elevated 17-OHP concentration.

Adenoma↗
PubMed2001

Increased exocytosis of secretory granules in contrast to reduced serum hormone levels in pituitary adenomas of humans and rats treated with dopamine agonist.

The release of secretory granules outside the cells increased in frequency, in inverse proportion to the marked decrease in serum prolactin (PRL) levels in human prolactin-secreting adenomas (PRLomas) treated with bromocriptine (CB), a dopamine agonist. Rat pituitary adenomas induced by diethylstilbestrol also showed an increase in exocytosis of the granules despite a reduction in serum PRL levels after CB treatment. To elucidate this curious phenomenon, which is contrary to current general knowledge that serum hormone levels are sustained by the exocytosis of the secretory granules, we combined morphometric analysis with analyses using a cell fractionation technique and immunocytochemistry. The results indicated that the proteins in secretory granules consisted of 90% nonhormonal proteins and 10% PRL. CB treatment did not change the levels of the former, while the levels of the latter were markedly reduced. Immunocytochemistry, using a protein-A gold method, revealed that the secretory granules in rats treated with CB contained fewer PRL molecules than the controls. Serum PRL elevation caused by the exocytoses, estimated by counting the exocytotic granules, were markedly lower (less than 10%) in CB-treated rats than in the controls. It was suggested that, after CB treatment, the composition of secretory granules altered, or that nonhormonal constituents in the granules disintegrated more slowly, and that the granules became detectable at the site of release for a longer period. Consequently, although granules that appear ultrastructurally similar to those in untreated adenomas are observed to be more frequently released in treated adenomas, it seems that they no longer contribute to raising the serum PRL levels.

Adenoma↗
PubMed2001

Macrophage myeloperoxidase regulation by granulocyte macrophage colony-stimulating factor in human atherosclerosis and implications in acute coronary syndromes.

Inflammation and oxidative stress contribute to the pathogenesis of many human diseases including atherosclerosis. Advanced human atheroma contains high levels of the enzyme myeloperoxidase that produces the pro-oxidant species, hypochlorous acid (HOCl). This study documents increased numbers of myeloperoxidase-expressing macrophages in eroded or ruptured plaques causing acute coronary syndromes. In contrast, macrophages in human fatty streaks contain little or no myeloperoxidase. Granulocyte macrophage colony-stimulating factor, but not macrophage colony-stimulating factor, selectively regulates the ability of macrophages to express myeloperoxidase and produce HOCl in vitro. Moreover, myeloperoxidase-positive macrophages in plaques co-localized with granulocyte macrophage colony-stimulating factor. Pro-inflammatory stimuli known to be present in human atherosclerotic plaque, including CD40 ligand, lysophosphatidylcholine, or cholesterol crystals, could induce release of myeloperoxidase from HOCl production by macrophages in vitro. HOCl-modified proteins accumulated at ruptured or eroded sites of human coronary atheroma. These results identify granulocyte macrophage colony-stimulating factor as an endogenous regulator of macrophage myeloperoxidase expression in human atherosclerosis and support a particular role for the myeloperoxidase-expressing macrophages in atheroma complication and the acute coronary syndromes.

Arteriosclerosis↗
PubMed2001

Surgical results in patients with double outlet right ventricle: a 20-year experience.

BACKGROUND: The objective of this study was to review our surgical strategy in children with double outlet right ventricle and to assess risk factors for early and late mortality and reoperation. METHODS: Patients (n = 124; June 1980 to January 2000; age range, 7 days to 16 years; mean, 2.8 years) who underwent repair of double outlet right ventricle. The patients were divided into three groups. Group 1 (n = 47) had noncomplex patients with atrioventricular concordance, a single ventricular septal defect, balanced ventricles, no straddling atrioventricular valves, and no major pulmonary artery anomalies. Group 2 (n = 39) included patients with double outlet right ventricle and a subpulmonary ventricular septal defect (Taussig-Bing). Group 3 (n = 38) had patients with complex anomalies including straddling atrioventricular valves, atrioventricular septal defects or a hypoplastic valve or ventricle, or a combination of atrioventricular septal defects and hypoplastic valve or ventricle. RESULTS: Four types of definitive repairs were performed: (1) intraventricular tunnel repair with a baffle from the left ventricle to the aorta (n = 53); (2) use of a valved or nonvalved conduit (n = 20); (3) arterial switch operation with a patch committing the left ventricle to the neo-aorta (n = 16); and (4) cavopulmonary shunt and Fontan procedures (n = 33). Two patients with late postoperative cardiomyopathy had heart transplantation. Potential risk factors included location of the largest ventricular septal defect, presence of additional ventricular septal defects, ventricular outflow obstruction or hypoplasia, or both ventricular outflow obstruction and hypoplasia, previous palliation, and type of definitive operation. There were six early deaths (4.8%) and four late deaths (3.2%), and two heart transplants (1.6%). Overall 15-year survival was 95.8%, 89.7%, and 89.5% for groups 1, 2, and 3, respectively (p = 0.08). Thirteen patients (11.4%) have required 15 reoperations. Mean follow-up for survivors was 76.6 +/- 52.8 months. Up-to-date follow-ups are available on 114 surviving patients. Ninety-five of these patients (83.3%) were in New York Heart Association class I, and the remaining 19 patients (16.7%) were in New York Heart Association class II. Freedom from reoperation was 87%, 72%, and 100% at 15 years for groups 1, 2, and 3, respectively (p = 0.11). CONCLUSIONS: Survival was high for all patients with double outlet right ventricle undergoing intraventricular tunnel repair, arterial switch operation, and repair with a conduit or a modified Fontan procedure. Careful attention to preoperative anatomy dictates the best surgical approach and will enhance outcomes.

Adolescent↗
PubMed2001

Cytoarchitecture of central chemoreceptors in the mammalian ventral medulla.

We reviewed the previous reports on the fine anatomy of the mammalian ventral medulla with special attention to the cytoarchitecture of the superficial chemosensitive regions to summarize what is known, what is not yet known, and what should be studied in the future. We also reviewed studies on anatomical relationship between neurons and vessels, and morphological studies on dendrites of respiratory or chemosensitive neurons. When we compared the morphological reports on the ventral and dorsal putative chemosensitive regions, similarities were found as follows. Chemosensitive cells were often found not only near the ventral surface but near the dorsal surface of the brainstem. Dendritic projection towards the surface was a common characteristic in the ventral and dorsal chemosensitive neurons. Morphological abnormality in the brainstem of sudden infant death syndrome victims was also summarized. On the basis of the previous reports we discussed the perspective on the future study on central chemoreception. Among various unanswered questions in central chemosensitivity studies, physiological significance of surface cells and surface extending dendrites is the most important topic, and must be thoroughly investigated.

Animals↗
PubMed2001

B-mode ultrasonographic investigations of morphological changes in endarterectomized carotid artery.

BACKGROUND: The aim of this study was to assess morphological changes in the endarterectomized carotid region using B-mode ultrasonography (USG). METHODS: USG examinations were performed on 54 Japanese patients who underwent carotid endarterectomy (CEA). The endarterectomized regions were periodically investigated and the intima-media thickness (IMT) was measured. RESULTS: Postoperative USGs revealed an evident step formation (type I: 20.4%), a gentle slope (type II: 42.6%), or complete smoothness (type III: 37.0%) at the junction of the endarterectomized carotid region and the common carotid artery (CCA). The IMT of the CCA progressively increased from type I to type III. Patients were followed up for an average of 2.7 years. The new intima-media complex (IMC) was confirmed in all cases after 9 months; it was visualized as an isoechoic layer (7%) or a mixture of iso- and hypoechoic layers (93%). Changes in the IMT during the follow-up period were classified into three groups: no change (group I: 23.1%), decrease (group II: 15.4%), and increase (group III: 61.5%). CONCLUSIONS: USG is useful to clarify the complicated healing processes of the endarterectomized carotid artery.

Adult↗
PubMed2001

Surgical management of renal cell carcinoma invading into the liver: radical nephrectomy en bloc with right hepatic lateral sector.

Renal cell carcinoma demonstrates expansive growth and invasion of adjacent structures. Direct liver extension, although uncommon, is a dismal prognostic sign. We propose radical nephrectomy en bloc with right lateral sector (segments 6 and 7) of the liver. The operative procedure was performed in 2 male patients, 61 and 81 years of age, both with renal cell carcinoma and direct hepatic extension. The patients had no evidence of disease at 100 and 57 months after resection. This procedure may help cure selected patients with renal cell carcinoma invading the liver.

Aged↗
PubMed2001

Diagnostic results before and after introduction of autofluorescence bronchoscopy in patients suspected of having lung cancer detected by sputum cytology in lung cancer mass screening.

For the purpose of early detection, we have conducted population-based mass screening for lung cancer by sputum cytology since 1982. Although detection of lung cancer in its early stage is important for a good prognosis, it is often difficult to localize lesions in roentgenographically occult cancer. To clarify the role of autofluorescence bronchoscopy in localizing tumors in patients with roentgenographically occult cancer, we analyzed our diagnostic results. Fifty patients who had been detected by sputum cytology were screened by the light-induced fluorescence endoscope (LIFE)-Lung System from November 1997 to April 1999. We compared the results according to the screening methods: conventional bronchoscopy alone versus LIFE with conventional white-light bronchoscopy (November 1997 to April 1999). Twenty-eight cancerous lesions and 39 borderline lesions were detected by LIFE. Of the 39 borderline lesions, nine were detected only by LIFE. Multicentric lesions including cancer or dysplasia were also detected in 21 of the 50 patients by LIFE. The sensitivity by white-light bronchoscopy alone was 85.3%, whereas that of the LIFE-Lung System with white-light bronchoscopy was 94.1% (P=0.078). There were no cancerous lesions in the area observed as normal by LIFE. We also compared the diagnostic results of two localization methods: brushing of all bronchi (September 1986 to December 1990) and the LIFE-Lung System (November 1997 to April 1999). Although this was a historical comparison, the number of detected borderline lesions increased, which led to a high detection rate in patients with suspected-positive sputum (P=0.0006) by the LIFE-Lung System. In conclusion, the LIFE-Lung System is a safe and non-invasive system for detecting small intraepithelial lesions of the tracheobronchial tree. Autofluorescence bronchoscopy is more efficacious for localizing intraepithelial lesions and places fewer burdens on the patient than brushing of all bronchi.

Bronchoscopy↗
PubMed2001

Hyperthermia: is it an ominous sign after cardiac arrest?

OBJECTIVE: To clarify the clinical characteristics of hyperthermia at an early stage after resuscitation from cardiac arrest (CA). MATERIALS AND METHODS: We reviewed the medical records of 43 adult patients with non-traumatic out-of-hospital CA, who survived for longer than 24 h after admission to our intensive care unit (ICU) between January, 1995, and December, 1998. The patients were divided into two groups: a clinical brain death (CBD) group (n=23) and a non-CBD group (n=20), and various factors relating to hyperthermia were compared between the two groups. RESULTS: The mean value of peak axillary temperatures within 72 h of admission was 39.8+/-0.9 degrees C for the CBD group, which was significantly greater than 38.3+/-0.6 degrees C for the non-CBD group (P<0.0001). The time of occurrence of the peak axillary temperature was at 19+/-16 h of admission in the CBD group and 20+/-18 h in the non-CBD group (not significantly different). There were no significant differences in risk factors relating to the occurrence of hyperthermia between the two groups, except for the number of patients who received epinephrine at ICU. In 23 patients with a peak axillary temperature of > or =39 degrees C during the first 72 h of hospitalization, brain death was diagnosed in 20 patients, whereas only 3 of 20 patients having a peak axillary temperature of <39 degrees C developed brain death (odds ratio, 37.8; 95% confidence interval, 6.72-212.2). CONCLUSION: Hyperthermia at an early stage after resuscitation from CA may be associated with the outcome of brain death.

Aged↗
PubMed2001

Significance of elevated serum interleukin-8 in patients resuscitated after cardiopulmonary arrest.

The objectives of this study were to analyze changes in serum interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha) levels in patients that restored spontaneous circulation after cardiopulmonary arrest (CPA), and to clarify the cause and significance of elevated serum cytokines after resuscitation. Twenty-eight patients who were admitted to our hospital after out of hospital CPA were studied. Patients' IL-8 levels and TNF-alpha levels in serum increased to a peak within 12 h and within 6 h after the return of spontaneous circulation (ROSC), respectively. Serum IL-8 levels in patients who died or became brain dead within 1 week after ROSC were significantly higher than those in other patients. In stepwise multiple regression analysis, maximum IL-8 values were significantly correlated with maximum TNF-alpha values within post-ROSC 24 h, with the total dose of administered epinephrine and with peripheral neutrophil counts. It is especially noteworthy that the total dose of epinephrine administered during and after resuscitation markedly influenced the elevation of serum IL-8 after ROSC. The increases in serum IL-8 induced by excessive administration of epinephrine might be harmful in the ROSC-patients resuscitated after CPA.

Cardiopulmonary Resuscitation↗
PubMed2001

Characteristics of plasma extracellular SOD in burned patients.

The aim of this study was to examine three types of superoxide dismutase (SOD) in plasma after burns, and especially to clarify the characteristics of plasma extracellular SOD (EC-SOD) in burned patients. A total of 71 blood samples were collected from 18 patients on arrival, day 1, day 3 and day 5 after burns. We measured three types of SOD (Mn, Cu/Zn, EC) in plasma using ELISA, and the relationships among the three types of SOD concentrations were examined. We next analyzed the characteristics of plasma EC-SOD using stepwise multivariate regression analysis. Any plasma SOD isoenzyme concentration measured after burns was beyond the normal range and EC-SOD accounted for the major part of plasma SODs. EC-SOD and Cu/Zn-SOD were positively correlated, whereas Mn-SOD was not related to the other SODs. Also, plasma EC-SOD was significantly related to existence of inhalation injury, %TBSA and age, respectively. The plasma EC-SOD might therefore play some roles in the pathophysiology of burned patients.

Adult↗
PubMed2001

Effect of lactate on the synaptic potential, energy metabolism, calcium homeostasis and extracellular glutamate concentration in the dentate gyrus of the hippocampus from guinea-pig.

Towards understanding the role of glycolysis on synaptic function, we examined the effect of lactate on synaptic potential, energy metabolism, Ca(2+) homeostasis and extracellular glutamate in the dentate gyrus of guinea-pig hippocampus. Postsynaptic population spikes were recorded from the granule cell layer of the dentate gyrus in guinea-pig hippocampal slices after replacing glucose with lactate in the perfusion medium. Population spikes were not maintained and spontaneously recovered around 35min after the replacement of glucose with lactate. However, ATP levels of the dentate gyrus remained unchanged while those during the glucose-free condition decreased to 73% of the initial levels at 60min. Intracellular Ca(2+) was measured with the calcium indicator dye fura-2 AM, and the population spike was recorded simultaneously. Ca(2+) levels increased concomitantly with the early decay of synaptic potentials, and recovered partially with the spontaneous recovery of synaptic potentials. The time course of decay of population spikes and the increase of Ca(2+) levels during lactate replacement were similar to those during glucose deprivation. Increase in Ca(2+) levels during lactate replacement was completely blocked by the ryanodine receptor/calcium release channel antagonist dantrolene. Glutamate was released more significantly in the medium during lactate replacement than with normal Ringer solution, and less than that during glucose deprivation. Addition of the N-methyl-D-aspartate blocker, D-(-)-2-amino-5-phosphonovaleric acid, and the L-type calcium channel blocker, nimodipine, but not dantrolene blocked spontaneous recovery of population spikes. The results indicate that lactate can maintain energy levels in hippocampal slices, but cannot maintain ion homeostasis in granule cells of the dentate gyrus. Glycolysis plays an important role in maintaining ion homeostasis, and activation of N-methyl-D-aspartate and L-type calcium channels is necessary for support of synaptic function by lactate utilization.

2-Amino-5-phosphonovalerate↗
PubMed2001

Lens epithelial cell regeneration of a capsule-like structure during postoperative healing in rabbits.

PURPOSE: To determine whether lens epithelial cells (LECs) can regenerate the lens capsule during healing after lens extraction and intraocular lens (IOL) implantation. SETTING: Department of Ophthalmology, Wakayama Medical College, Japan. METHODS: Extracapsular lens extraction and IOL implantation were performed in 5 adult albino rabbits. Lens capsules were examined histologically and immunohistochemically 3 and 5 months later. RESULTS: Lens epithelial cells proliferated and regenerated lens fibers within the capsular bag. A multilayered homogenous capsule-like structure was present in the equatorial region. The structures contained type IV collagen but not type I collagen. CONCLUSION: Lens epithelial cells can regenerate lens capsule-like structures during healing after lens extraction. Postoperative LECs without phenotypic conversion to a fibroblastic type may produce this structure.

Animals↗
PubMed2001

Comparison of Scheimpflug images of posterior capsule opacification and histological findings in rabbits and humans.

PURPOSE: To compare the posterior capsule opacification in Scheimpflug photographic images produced by an electronic anterior eye segment analysis system with the histopathological findings in rabbits and humans. SETTING: Department of Ophthalmology, Wakayama Medical College, Japan. METHODS: Opacified posterior capsules were photographed using the EAS-1000 system (Nidek) and were then extracted during vitreous surgery for proliferative diabetic retinopathy or proliferative vitreoretinopathy in 2 patients. In rabbits, phacoemulsification and aspiration (PEA) with intraocular lens (IOL) implantation was performed. The IOL was implanted in the bag or in the sulcus. After intervals of healing, the posterior capsule was photographed with the EAS-1000 and the animals were then killed. In both clinical and experimental specimens, the posterior capsule was processed for light microscopic histology and immunohistochemistry. RESULTS: Opacified human capsules were well imaged by the EAS-1000. Histology showed that lens epithelial cells proliferated with and without an accumulation of extracellular matrix. Details such as rolling of the capsulotomy edge were seen well. Regenerated lens fibers of Soemmering's ring were seen as a mass within the capsule. In the rabbit model, Scheimpflug images accurately represented the capsules as they appeared histologically. CONCLUSION: The EAS-1000 system provided faithful, relatively high-resolution images that corresponded to the histologic findings in the posterior capsules after PEA-IOL surgery in humans and rabbits.

Aged↗