Biomedical subjects

T Yamaguchi

Publications and source records attributed to T Yamaguchi.

At least 559 records · Page 31Linked to original sources

PubMed1998

Novel guide catheter for left coronary intervention via a right upper limb approach.

We designed a novel guide catheter specifically for interventions to the left coronary artery via a right upper limb approach. The catheter has a novel first loop design which utilizes the angle between the right subclavian and innominate arteries for support. The first loop introduces the catheter into the correct position and generates powerful and coaxial back-up power. We report successful implantation of Palmaz-Schatz stents in five cases using this 6 Fr. catheter.

Aged↗

PubMed1998

Carbon monoxide as a regulator of bile canalicular contractility in cultured rat hepatocytes.

This study aimed to examine the mechanism(s) by which carbon monoxide (CO), a product of heme oxygenase reaction, controls the contractility of bile canaliculus (BC) in hepatocytes. When BCs associated with the couplet cells in cultured rat hepatocyte suspension were observed using time-lapse video microscopy, they exhibited periodical contractions with a most-probable interval of 6 minutes under our experimental conditions. The addition of 1 micromol/L zinc protoporphyrin IX (ZnPP), a potent inhibitor of heme oxygenase, to the culture medium elicited a 40% shortening of the interval time together with an increase in intracellular calcium concentrations, while the same concentration of iron protoporphyrin IX did not induce such changes. The production of CO, which was 0.5 nmol/h/10(8) cells in the absence of ZnPP, diminished to less than 0.1 nmol/h/10(8) cells upon application of ZnPP. The ZnPP-elicited increases in both contractile frequency and intracellular calcium concentrations were attenuated by the addition of 1 micromol/L CO or 50 micromol/L 1,2-bis(2-aminophenoxy) ethane-tetraacetate, a calcium chelator. Clotrimazole or metyrapone, inhibitors of cytochrome P450-dependent monooxygenase activities, also attenuated the ZnPP-induced elevation of the contractile frequency. On the other hand, intracellular cyclic guanosine monophosphate (cGMP) contents were not altered significantly by the application of ZnPP or by CO. These results indicate that CO generated by heme oxygenase controls the BC function by changing intracellular calcium concentrations presumably through a mechanism involving the cytochrome P450 reaction.

Animals↗

PubMed1998

Rabbit models of bucket-handle-like meniscal tear.

After radial tears were artificially created in the periphery of the middle third of the lateral menisci in Japanese white male rabbits, the menisci were sampled postoperatively at 2, 4, 6, 12 and 24 weeks. We noted that radial tears often progressed to longitudinal tears, and the length of longitudinal tears increased with time. On the other hand, the areas in which radial tears had been artificially created were filled with granulation-like tissue. Radial tears thus created may lead to bucket-handle-like tears of the menisci.

Animals↗

PubMed1998

Subcarinal neurogenic tumor: report of a case.

We present herein the rare case of a 63-year-old man in whom a subcarinal tumor, demonstrated by enhanced chest computed tomograms (CT), was subsequently confirmed to be a neurilemmoma by histological examination following tumor resection through a diagnostic thoracoscopy. Magnetic resonance imaging (MRI) and transesophageal ultrasonogram findings excluded the possibility of malignant lymphoadenopathy. As the patient was also found to have an elevated level of the squamous cell carcinoma (SCC) tumor marker which did not resolve postoperatively, close follow-up will be required.

Humans↗

PubMed1998

Pulmonary histoplasmosis in a Japanese male: report of a case.

A case of pulmonary histoplasmosis, which is rare in Japan, is reported herein. A 43-year-old man who had worked in Mexico for 2 years and had come back to Japan 3 months earlier, presented at our hospital because of an abnormal shadow on his chest roentogenogram with no symptoms. His chest roentogenogram as well as chest computed tomograms revealed a 2-cm-diameter nodule in the anterior basal segment of his right lung and an enlargement of the subcarinal lymph node. Although these pictures seemed to indicate an advanced lung cancer, no malignant cells were found based on the brushing cytology findings after bronchoscopy. An exploratory thoracoscopic tumor resection and biopsy of the enlarged lymph node led to a histological diagnosis of an abscess due to histoplasma. The hospital course was uneventful. Postoperatively, amphotericin B was administered for 1 year. This is the eighth case of pulmonary histoplasmosis reported in Japan. A pulmonary nodule together with mediastinal lymphoadenopathy seems to be characteristic in these patients. Histoplasmosis should therefore be considered in the differential diagnosis, since overseas travel has now become common-place for the Japanese.

Adult↗

PubMed1998

Serum level of carboxyterminal propeptide of type I procollagen in haemodialysis patients.

Serum concentrations of carboxyterminal propeptide of type I procollagen (PICP) and carboxyterminal parathyroid hormone (C-PTH) were measured in 33 haemodialysis patients. Serum levels of PICP and C-PTH in the haemodialysis group were significantly higher than those in the controls. Although there was no correlation between serum C-PTH and creatinine, a positive correlation was found between PICP and creatinine. This indicates that the measurement of PICP in serum is useful for monitoring metabolic bone diseases in haemodialysis patients.

Adult↗

PubMed1998

[Evaluation of cerebral circulation during cardiopulmonary bypass using near-infrared spectroscopy].

Cerebral oxygenation level during cardiopulmonary bypass (CPB) was measured using near-infrared spectroscopy as a monitor of cerebral circulation in 30 patients. Six adult cases with thoracic aortic aneurysm were operated on using selective cerebral perfusion (SCP). CPB was established under moderate hypothermic temperature in 9 adult cases (hypothermic group, lowest blood temperature during CPB; 25 degrees C) and under normothermic temperature in 9 adult cases (normothermic group, lowest blood temperature during CPB; 34 degrees C). In congenital cases (n = 6), CPB was established under moderate hypothermic temperature (congenital group, lowest blood temperature; 25 degrees C). The oxyhemoglobin (HbO2) level showed a significant positive correlation with cerebral blood flow during SCP (r = 0.715). There was no significant correlation between SjO2 and HbO2 in the SCP group. The HbO2 levels in the hypothermic group after 30 and 60 min, from the initiation of CPB and 30 min. before the weaning of CPB were significant lower than the control level (p < 0.05). HbO2 levels in the congenital group after 0, 30 and 60 min. from the initiation of CPB and 30 min. before the weaning of CPB were significantly lower than the control level (p < 0.01). The deoxyhemoglobin (HbR) level in the hypothermic group after 30 and 60 from the initiation of CPB and 30 min. before the wearing of CPB were significantly higher than the pre level (p < 0.05). The mixed venous saturation (SvO2) in the normothermic group showed significant lower levels than those in the hypothermic group (p < 0.01). However, there was no significant difference in HbO2 levels between the two groups. In conclusion, these results suggest that near-infrared spectroscopy may be a noninvasive and useful technique for the cerebral circulation monitoring during CPB.

Adolescent↗

PubMed1998

YM90K, an AMPA receptor antagonist, protects against ischemic damage caused by permanent and transient middle cerebral artery occlusion in rats.

The neuroprotective effect of YM90K, a potent AMPA receptor antagonist, was examined in rats with permanent and transient occlusion of middle cerebral artery (MCA) using intraluminal suture occlusion method. In rats with permanent MCA occlusions, two types of occluders were used to compare the efficacy of YM90K. When a 4-0 (diameter: 0.19 mm) suture was used, YM90K (20 mg kg(-1) h(-1) i.v. infusion for 4 h) significantly reduced infarct volume (P<0.05) and neurologic deficits (P<0.05) 24 h after MCA occlusion. Infarct volume was also reduced by YM90K at the same dose (P<0.01) when severe ischemia was induced by a 3-0 (diameter: 0.23 mm) suture. In rats with transient (3 h) MCA occlusions, a 10-mg kg(-1) h(-1) dose of YM90K that did not show significant protection in rats with permanent MCA occlusion offered neuroprotective effects. These data demonstrate that YM90K provides cerebral neuroprotection against a wide range of ischemic insults.

Animals↗

PubMed1998

BAL surfactant protein A and Clara cell 10-kDa protein levels in healthy subjects.

Lung surfactant protein A (SP-A) and Clara cell 10-kDa protein (CC10) are the most abundant proteins produced locally in the lower respiratory tract, as assessed in bronchoalveolar lavage (BAL) analysis. However, it is not known what factors influence SP-A and CC10 levels in BAL fluids, and the relationship between SP-A and CC10 levels in BAL fluids has been unclear. We measured SP-A and CC10 concentrations in BAL fluids from 11 healthy nonsmokers and 12 healthy smokers by enzyme-linked immunosorbent assays using specific antibodies. Mean SP-A and CC10 levels in BAL fluids of healthy smokers were significantly lower than those of healthy nonsmokers. SP-A values correlated significantly with CC10 and phospholipid values in BAL fluids. On BAL examinations using three 50-ml aliquots, the mean SP-A level in the second lavage was 2.0-fold and 2.4-fold, respectively, of that in the first and third lavages, and the mean CC10 level in the first lavage was 5.0-fold and 5.6-fold, respectively, of that in the second and third lavages. We conclude that BAL fluid SP-A and CC10 levels are influenced by the BAL methods and by cigarette smoking. There is a significant positive correlation between SP-A and CC10 values in BAL fluids of healthy subjects.

Adult↗

PubMed1998

Reciprocal expression of bcl-2 and p53 oncoproteins in urothelial dysplasia and carcinoma of the urinary bladder.

In order to investigate if and when the bcl-2 oncoprotein is activated in bladder tumorigenesis and its relationship with p53 overexpression and patient survival, we studied bcl-2 and p53 expression immunohistochemically in matched normal urothelium, dysplasia and cancer specimens selected by step-sectioning from 54 radically resected bladders for non-metastatic transitional cell carcinoma (TCC). In normal urothelium and mild dysplasia, bcl-2 was restricted to the basal cell compartment, while in moderate and severe dysplasia its expression was detectable also in the upper regions. Excess bcl-2 immunoreactivity was found in 27 (50%) of carcinomas, and a larger proportion of high-grade TCCs showed bcl-2 expression compared with that of low-grade TCCs (P < 0.05). Overexpression of p53 protein showed a increasing trend toward the progression of bladder tumorigenesis (P < 0.01) and a significant reciprocal correlation was found between bcl-2 and p53 expression in either various dysplasias (P < 0.01) or carcinoma (P < 0.05). With the evolution from mild dysplasia to carcinoma in individual cases, loss of bcl-2 expression was more frequently observed in superficial (P < 0.02) or low-grade carcinoma (P < 0.05) than in muscle-invasive or high-grade carcinoma. Furthermore, patients with negative immunostaining for both bcl-2 and p53 in cancer lesions had a significantly more favorable prognosis compared with those with positive immunostaining for the oncoproteins (P < 0.05), although bcl-2 by itself did not predict patient survival. We suggest that aberrant activated bcl-2, which is seen earlier than p53, appears to facilitate bladder tumorigenesis and to enhance tumor aggression in some extent.

Aged↗

PubMed1998

Radiographic and histologic patterns of calcification in chondromyxoid fibroma.

OBJECTIVE: To evaluate the frequency of radiologic and histologic manifestations of matrix calcification in chondromyxoid fibromas. PATIENTS: Forty-four cases of chondromyxoid fibroma were reviewed. The age range of the patients was 3-70 years (average 29 years). RESULTS: Calcification was found microscopically in 15 cases (34.1%). In five cases (12.5%) it was demonstrated on plain films or CT. The age range of the patients with microscopic evidence of calcified matrix was 14-70 years (mean 46 years), while that of the patients with non-calcified lesions was 3-59 years (average 21 years). All but two of the patients who showed microscopic calcification in the tumors were over 40 years of age. Four microscopic patterns of calcification were observed: coarse granular, circumscribed, trabecular, and "chicken-wire." CONCLUSIONS: Calcification in chondromyxoid fibroma was found more frequently than in previously reported studies. There was a tendency for this phenomenon to occur in the tumors of older patients, particularly those over 40 years old, and in chondromyxoid fibromas situated in flat bones, including ribs.

Adolescent↗

PubMed1998

Interleukin-15 effectively potentiates the in vitro tumor-specific activity and proliferation of peripheral blood gammadeltaT cells isolated from glioblastoma patients.

GammadeltaT cells play a regulatory role in both primary and metastatic tumor growth in humans. The mechanisms responsible for the activation and proliferation of circulating gammadeltaT cells should be fully understood prior to their adoptive transfer to cancer patients. We have examined in vitro functional effects of interleukin-15 (IL-15) on highly purified gammadeltaT cells isolated from glioblastoma patients. GammadeltaT cells constitutively express the heterotrimeric IL-2 receptor (IL-2R) alpha betagamma, but the levels of IL-2Rbeta or gamma expression were not increased by incubation with saturating amounts of IL-15. IL-15 was shown to induce a maximal gammadeltaT cell proliferation, although at much higher concentrations (at least 2000 U/ml) than IL-2 (100 U/ml). Submaximal concentrations of IL-15 plus low concentrations of IL-2 produced an additive proliferative response. In contrast to the IL-2-induced response, this activity was completely or partially abrogated by anti-IL-2Rbeta, or anti-IL-2Rgamma antibodies, but not by anti-IL-2R alpha antibodies. Incubation of gammadeltaT cells in the presence of IL-15 resulted not only in the appearance of NK and LAK activity, but also in specific autologous tumor cell killing activity, an additive effect being seen with IL-15 and IL-2. This IL-15-induced tumor-specific activity could be significantly blocked by anti-IL-2Rgamma and anti-IL-2R-beta mAb, but not by anti-IL-2R alpha mAb. Thus, in contrast to IL-2, IL-15 activates tumor-specific gammadeltaT cells through the components of IL-2Rbeta and IL-2Rgamma, but not IL-2R alpha. These enhanced in vitro tumor-specific and proliferative responses of gammadeltaT cells seen with IL-15 suggest a rational adjuvant imunotherapeutic use of gammadeltaT cells in cancer patients.

Antibodies, Monoclonal↗

PubMed1998

Effects of hyaluronic acid on meniscal injury in rabbits.

Using a model of meniscal injury in rabbit, the effects of hyaluronic acid (HA) injection into the joint on the rate of filling area and the cell shape in the defects were studied. After a cylindrical defect was made in the anterior horn of the lateral meniscus, HA was injected into the joint once a week. At 1 and 6 weeks after the beginning of the weekly injections, the meniscus was compared with a control, which was injected with phosphate buffer instead of HA. The healing in the defect progressed with time. HA administration caused a significant increase in the rate of filling area in the defect. The cell population in the repair tissue changed from fibroblast-like cells to chondrocyte-like cells with the progress of repair. At 6 weeks, the ratio of chondrocyte-like cells to all cells in the repair tissue of the HA-treated meniscus was higher than that of control. These data indicate that HA increases the healing rate of meniscal injury.

Animals↗

PubMed1998

A new L527R mutation of the betaIGH3 gene in patients with lattice corneal dystrophy with deep stromal opacities.

Mutations in the betaIGH3 gene on chromosome 5q31 cause five distinct autosomal dominant corneal dystrophies: granular Groenouw type I, Reis-Bücklers', lattice type I and IIIA. and Avellino corneal dystrophies. We present here a new mutation of the betaIGH3 gene in patients with late-onset lattice corneal dystrophy manifest as a deep stromal opacity. To test the previously reported R124C, R124H, P501T, R555W, and R555Q mutations of the betaIGH3 gene, 30 patients and 11 normal relatives from 16 independently ascertained families with lattice corneal dystrophy, 49 patients and 12 normal relatives from 40 independently ascertained families with other corneal dystrophies, and 40 unrelated normal volunteers, were analyzed. A L527R (CTG/CGG) mutation of the betaIGH3 gene was found in 6 unrelated patients with lattice corneal dystrophy. A retrospective review of the patients' records showed that the opacities were deep in the stromal layer and of late onset. The mutation was a heterozygous single base-pair transversion from T to G of the second nucleotide position of codon 527. This caused the substitution of arginine for leucine. These six patients did not have mutations in codons 124, 501, or 555. The L527R mutation was not detected in the other corneal dystrophies or 40 normal volunteers. Although phenotypic variations in the size and shape of the deposits were found, all patients with the L527R mutation showed deposits deep in the stromal layer. We conclude that there are now at least six different mutations that have been detected in the betaIGH3 gene on chromosome 5q31 and that lead to corneal dystrophy.

Aged↗

PubMed1998

Increased urinary excretion of bilirubin metabolites in association with hyperbilirubinemia after esophagectomy.

This study was conducted to investigate the rationale for postoperative hyperbilirubinemia after major surgery. The serum bilirubin values and urinary excretion of bilirubin metabolites (BM) were monitored in 11 patients who underwent esophagectomy via right thoracotomy for esophageal cancer. Both the serum bilirubin values and the urinary excretion of BM increased postoperatively in all patients. The maximum serum bilirubin level in four patients with septic complications, two of whom developed pneumonia and two, anastomotic leakage (group A), was significantly higher at 5.25+/-4.16 mg/dl than in the remaining patients without septic complications (group B), at 2.11+/-0.07 mg/dl. The peak value of urinary BM was 99.5+/-88.2 micromol/day in group A and 23.5 +/-26.7 micromol/day in group B. The correlation between the level of serum bilirubin and urinary BM excretion was found to be significant. Thus, the metabolism of bilirubin was increased by extensive surgical stress and septic insult.

Aged↗

PubMed1998

Lipoprotein disorder in brain infarction and hemorrhage.

The cholesterol, triglyceride, and apolipoprotein B content of very low-, intermediate-, low-, and high-density lipoprotein fractions (separated by ultracentrifugation) and plasma were measured in healthy controls and patients with atherothrombotic infarction (26), lacunar infarction (26), and brain hemorrhage (14). In both atherothrombotic and lacunar infarction, increased plasma and low-density lipoprotein apolipoprotein B and a decreased low-density lipoprotein cholesterol/apolipoprotein B ratio were noted. In brain hemorrhage patients, a decreased ratio was also observed. These findings suggest that increased small dense low-density lipoprotein is a characteristic risk factor for atherothrombotic and lacunar infarction.

Adult↗

PubMed1998

Some characteristics of a cellular receptor for virulent infectious bursal disease virus by using flow cytometry.

A flow cytometric virus binding assay that directly visualizes the binding of infectious bursal disease virus (IBDV) to its target cells was established. The chicken B lymphoblastoid cell line, LSCC-BK3, which is permissive for IBDV infection, bound high levels of the virus. Another B lymphoblastoid cell line, LSCC-1104-B1, bound low levels of the virus, although it was nonpermissive. No virus binding was detected in nonpermissive T lymphoblastoid cell lines. In the binding assay to heterogeneous cell populations of chicken lymphocytes, IBDV (a highly virulent OKYM strain) bound to 94% cells in the lymphocytes prepared from the bursa of Fabricius, 37% cells in those prepared from the spleen, 3% cells in those prepared from the thymus, and 21% cells in those prepared from the blood. Most of the cells, which bound the virus, were surface immunoglobulin M (SIgM)-positive, but a small number of them were SIgM-negative. Additionally, the binding of IBDV to the LSCC-BK3 cells was affected by treatment of the cells with proteases and N-glycosylation inhibitors. These findings may indicate that the IBDV host range is mainly controlled by the presence of a virus receptor composed of N-glycosylated protein associated with the subtle differentiation stage of B-lymphocytes represented mostly by SIgM-bearing cells.

Animals↗

PubMed1998

Interleukin 15 activity in the rectal mucosa of inflammatory bowel disease.

BACKGROUND & AIMS: Interleukin (IL)-15 has been found to share many immunoregulatory activities in lymphocytes with IL-2. The aim of this study was to investigate IL-15 activity in organ cultures, localization of IL-15 messenger RNA (mRNA), and proliferation of lamina propria mononuclear cells (LPMCs) in response to recombinant IL-15 using the mucosal tissues obtained from patients with inflammatory bowel disease (IBD). METHODS: The contents of IL-15, tumor necrosis factor alpha, and IL-2 in the culture supernatant of the rectal mucosal tissues were determined by an enzyme-linked immunosorbent assay. Expression of IL-15 mRNA was analyzed by in situ hybridization, and proliferative response of LPMCs to recombinant IL-15 was determined by [3H]thymidine incorporation into DNA. RESULTS: Significantly greater IL-15 activity was detected in active IBD, and this elevation was also observed in inactive ulcerative colitis. In contrast, greater tumor necrosis factor alpha activity was observed only in active IBD, and IL-2 was not detected in organ cultures. In situ hybridization showed IL-15 mRNA in macrophages and epithelial cells in active IBD specimens, and recombinant IL-15 induced a dose-dependent proliferative response in LPMCs. CONCLUSIONS: Mucosal IL-15 may be involved in the pathogenesis of IBD as one of the important mediators in activation of mucosal immune cells.

Adolescent↗