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Biomedical subjects

H Okazaki

Publications and source records attributed to H Okazaki.

At least 91 records · Page 5Linked to original sources
PubMed1998

Significance of abnormal root mean square voltages in signal averaged electrocardiogram as a reliable predictor of sustained ventricular tachycardia.

The late potential is useful to predict patients with sustained ventricular tachycardia (VT). However, because positive predictive value for sustained VT is low, the validity of late potential for screening the patients to be studied by electrophysiological tests was not high. We examined 923 cases, including 63 cases of sustained VT. When we separated patients showing abnormal values of the root mean square voltage of the QRS end part 40 milliseconds (RMS40) into four groups, there was a tendency of a higher incidence of sustained VT with lower value of RMS40. When we conducted electrophysiological tests on 121 cases without sustained VT, it turned out a high induction rate of sustained VT in patients with low RMS40 values (RMS40 < 10 microV, 67%; < 20 microV, 30%; 20 microV, < or = 5%). We conclude abnormally low value (less than 10 microV) of RMS40 can be useful for screening the late potential-positive cases who are high risk for inducible sustained VT.

Electrocardiography↗
PubMed1998

Diesel exhaust particles stimulate human airway epithelial cells to produce cytokines relevant to airway inflammation in vitro.

BACKGROUND: Epidemiologic and experimental studies suggest that air pollution such as diesel exhaust particles (DEPs), one of the important air pollutants, may play a role in the increasing prevalence of allergic airway diseases. OBJECTIVE: We studied the effect of suspended particulate matter (SPM) and its main component, DEPs, on the production of IL-8 and granulocyte-macrophage colony-stimulating factor (GM-CSF) by human airway epithelial cells in vitro. METHODS: SPM obtained from high-volume air samplers and DEPs were added to cultured human nasal polyp-derived upper airway, normal bronchial, and transformed bronchial epithelial cells. Production of GM-CSF and IL-8 by airway epithelial cells was evaluated. RESULTS: Nontoxic doses of DEPs showed a significant stimulatory effect on IL-8 and GM-CSF production by these three kinds of epithelial cells in a dose- and time-dependent fashion. SPM had a stimulatory effect on GM-CSF, but not IL-8, production. These effects were abrogated by treatment with a protein synthesis inhibitor, cycloheximide, suggesting that the process required a de novo protein synthesis. On the double-chamber plates, airway epithelial cells responded to DEPs only when they were stimulated from the apical sides, which can be a model for in vivo environments. Neither charcoal nor graphite showed such stimulatory effects, indicating that the activity of DEPs did not derive from their particulate nature. Benzo(a)pyrene, one of the main aromatic hydrocarbons contained in DEPs, showed a stimulatory effect on the release of the cytokines, and this organic substance might have a causative effect on of the potency of DEPs. CONCLUSION: We conclude that SPM and DEPs, its main component, might be important air pollutants in the activation of airway epithelial cells for the release of cytokines relevant to allergic airway inflammation.

Allergens↗
PubMed1998

Papillary glioneuronal tumor: a new variant of mixed neuronal-glial neoplasm.

We describe the clinicopathologic features of nine cases of a unique papillary glioneuronal tumor (PGNT) exhibiting astrocytic as well as extensive and varied neuronal differentiation. The four male and five female patients studied ranged in age from 11 to 52 years (mean 27.7 years). They either presented with mild neurologic symptoms or were asymptomatic. Magnetic resonance imaging showed demarcated cystic, 1.5-cm to 7-cm contrast-enhancing masses; five involved the temporal lobe, two the parietal, and two the frontal. All but one were totally resected. No recurrence was noted despite a follow-up period of 3 years. Two microscopic components were evident: 1) compact pseudopapillae composed of hyalinized vessels covered by a single layer of glial fibrillary acid protein (GFAP)-positive astrocytes and 2) synaptophysin-positive neuronal cells of varying size, including neurocytes, ganglioid cells, and ganglion cells within neuropil. Immunostains for chromogranin-A were negative, as was in situ hybridization for chromogranin-A mRNA. Ultrastructurally, neuronal cells featured microtubule-containing processes and aberrant synaptic terminals, but dense core granules were rare. Overall, cellularity was moderate and atypia was minimal. No mitotic activity or necrosis was noted. The proportions of the two components varied, but essential morphologic findings were identical in all cases. In that the clinical, radiographic, and morphologic characteristics of PGNT are distinctive, it appears to represent a previously undescribed form of mixed neuronal-glial tumor of the central nervous system.

Adolescent↗
PubMed1998

Progressive viral-induced cirrhosis: serial MR imaging findings and clinical correlation.

PURPOSE: To determine which magnetic resonance (MR) imaging findings of cirrhosis change as disease severity progresses. MATERIALS AND METHODS: Seventy-six abdominal MR imaging studies in 38 patients (two per patient) with Child-Pugh grade A cirrhosis were retrospectively reviewed. All patients were followed up clinically and with MR imaging for 12 months or longer. MR images were used to determine volume indexes of the spleen and of each liver segment, as well as changes in hepatic contour, iron or fat deposition, and presence of varices and collateral vessels. RESULTS: During follow-up in patients with progressive cirrhosis (n = 13), the volume indexes of the anterior, posterior, and medial segments of the liver decreased significantly (P = .011, .013, .002, respectively), and the number of varices and collateral vessels increased significantly (P = .018). In patients with stable cirrhosis (n = 25), the volume indexes of the spleen, caudate lobe, and lateral segment increased significantly (P = .032, .018, .003, respectively). The atrophic index was significantly greater in progressive cirrhosis than in stable cirrhosis (P = .009). CONCLUSION: Progressive atrophy of the right hepatic lobe and the medial segment correlated with progression of clinical severity of cirrhosis, whereas increasing size of the caudate lobe and the lateral segment correlated with stability.

Adult↗
PubMed1998

Effect of hypoxia on pulmonary blood flow-segmental vascular resistance relationship in perfused cat lungs.

To investigate the effect of alveolar hypoxia on the pulmonary blood flow-segmental vascular resistance relationship, we determined the longitudinal distribution of vascular resistance while increasing blood flow during hyperoxia or hypoxia in perfused cat lungs. We measured microvascular pressures by the micropipette servo-null method, partitioned the pulmonary vessels into three segments [i.e., arterial (from main pulmonary artery to 30- to 50-micron arterioles), venous (from 30- to 50-micron venules to left atrium), and microvascular (between arterioles and venules) segments] and calculated segmental vascular resistance. During hyperoxia, total resistance decreased with increased blood flow because of a reduction of microvascular resistance. In contrast, during hypoxia, not only microvascular resistance but also arterial resistance decreased with increase of blood flow while venous resistance remained unchanged. The reduction of arterial resistance was presumably caused by arterial distension induced by an elevated arterial pressure during hypoxia. We conclude that, during hypoxia, both microvessels and arteries >50 micron in diameter play a role in preventing further increases in total pulmonary vascular resistance with increased blood flow.

Animals↗
PubMed1998

Acute acalculous cholecystitis in systemic lupus erythematosus: a case report and review of the literature.

A 27-year-old woman with systemic lupus erythematosus (SLE) was found to have acute acalculous cholecystitis. At the time of admission, the patient was not under corticosteroid or immunosuppressive therapy. Computed tomography (CT) and ultrasonography revealed findings in the gall bladder consistent with acute acalculous cholecystitis. Her abdominal pain completely disappeared following corticosteroid therapy, with dramatic improvement in the images of CT and ultrasonography. Six similar cases of SLE complicated with acute acalculous cholecystitis have been reported in the literature and they were all treated surgically by cholecystectomy or cholecystostomy. This is the first case report in which acute acalculous cholecystitis accompanying SLE was treated successfully by corticosteroid without surgical intervention.

Acute Disease↗
PubMed1998

The diameter of callus in leg lengthening: 28 tibial lengthenings in 14 patients with achondroplasia.

We investigated the relation between callus diameter during bone distraction and the occurrence of late fracture and deformity. We retrospectively reviewed 28 tibial lengthenings in 14 patients with achondroplasia. The minimal diameter of the lengthened zone was measured on radiographs, when the sliding mechanism of the lengthening device was released, and the callus diameter ratio in two planes (CDR; diameter of the callus/diameter of the tibia at the level of the osteotomy end) was calculated. The CDR correlated negatively with the distracted length. Late fracture or late angular deformity occurred in 6 of the 28 lengthenings. When the CDR was 85% or more in both planes, these complications did not occur, but when the CDR was 80% or less in either plane, they occurred in 6 of 20 bones. Careful attention should therefore be given not only to the continuity of the callus but also to its diameter.

Achondroplasia↗
PubMed1998

[SMANCS-TAE combined with PEI in the treatment for hepatocellular carcinoma].

From January 1996 to August 1997, 24 patients with advanced hepatocellular carcinoma (HCC) equal to or more than 2 cm (mean +/- SD; 4.1 +/- 3.0 cm) in main tumor diameter were treated by SMANCS-TAE (20 cases) or SMANCS-TAI (4 cases) combined with PEI. Six cases had solitary lesion, 16 cases had multiple lesions, and 2 cases had massive lesions. After this combination therapy, 21 of 24 cases had complete tumor necrosis. During 3 to 19 months follow up period, 12 cases had cancer-free survival (SMANCS-TAI; 3 cases), and 9 cases had tumor recurrences (3 cases were local recurrences and 6 cases involved new lesions). Two cases died of hepatic infarction and cancer death, however, the remaining 22 cases were surviving. SMANCS-TAE combined with PEI is useful treatment for advanced large or multiple HCC lesions in patients who are poor surgical risks.

Aged↗
PubMed1998

A close temporal relationship of liver disease to antiribosomal P0 protein antibodies and central nervous system disease in patients with systemic lupus erythematosus.

OBJECTIVE: To determine whether there is a close temporal relationship of liver disease to serum IgG and/or IgM antiribosomal P0 protein antibodies (anti-P0) and central nervous system (CNS) lupus in patients with systemic lupus erythematosus (SLE). METHODS: The study included 70 patients with active SLE. Of these, 30 had IgG and/or IgM anti-P0 and 14 had CNS lupus other than psychiatric disease (nonpsychiatric CNS lupus). Of these 14 patients, 11 had anti-P0. Laboratory manifestations of liver disease were retrospectively analyzed. RESULTS: Liver disease not attributed to any cause other than SLE (SLE liver disease) was present in 8 of the 11 patients with anti-P0 with nonpsychiatric CNS lupus (72.7%), in none of the 19 patients with anti-P0 without nonpsychiatric CNS lupus (0%), and in one of the 40 patients without anti-P0 (2.5%). The prevalence of SLE liver disease was significantly greater in patients with anti-P0 with nonpsychiatric CNS lupus than in the other 2 groups (p < 0.0001). Mean levels of liver enzymes (lactate dehydrogenase, glutamic oxaloacetic transaminase, glutamate pyruvate transaminase, gammaglutamyl transpeptidase) were significantly higher in patients with anti-P0 with nonpsychiatric CNS lupus than in the other 2 groups. Serial studies in 3 patients showed that the appearance of anti-P0 and liver dysfunction slightly preceded the onset of nonpsychiatric CNS lupus. CONCLUSION: Anti-P0 may be related to the pathogenesis of CNS lupus and SLE liver disease found simultaneously in SLE. The appearance of anti-P0 and liver dysfunction may predict onset of CNS lupus.

Adolescent↗
PubMed1997

Activation of protein-tyrosine kinase Pyk2 is downstream of Syk in FcepsilonRI signaling.

Aggregation of the FcepsilonRI, a member of the immune receptor family, induces the activation of proteintyrosine kinases and results in tyrosine phosphorylation of proteins that are involved in downstream signaling pathways. Here we report that Pyk2, another member of the focal adhesion kinase family, was present in the RBL-2H3 mast cell line and was rapidly tyrosine-phosphorylated and activated after FcepsilonRI aggregation. Tyrosine phosphorylation of Pyk2 was also induced by the calcium ionophore A23187, by phorbol myristate acetate, or by stimulation of G-protein-coupled receptors. Adherence of cells to fibronectin dramatically enhanced the induced tyrosine phosphorylation of Pyk2. Although Src family kinases are activated by FcepsilonRI stimulation and tyrosine-phosphorylate the receptor subunits, the activation and tyrosine phosphorylation of Pyk2 were downstream of Syk. In contrast, tyrosine phosphorylation of Pyk2 by stimulation of G-protein-coupled receptors was independent of Syk. Therefore, the FcepsilonRI-induced tyrosine phosphorylation of Pyk2 is downstream of Syk and may play a role in cell secretion.

Cell Adhesion↗
PubMed1997

Successful one-stage complete removal of an entire intravenous leiomyomatosis in the heart, vena cava, and uterus.

The patient was a 61-year-old woman who had intravenous leiomyomatosis (IVL) extending into the right ventricle of the heart from the uterus. Tumors in the heart and the inferior vena cava were removed under cardiopulmonary bypass and then after terminating the cardiopulmonary bypass, tumors in the abdominal cavity including uterine leiomyoma were removed. This is the first case of extended IVL in which all tumors were successfully removed at one time. If a tumor is found in the right ventricle in a woman who had or currently has uterine leiomyoma, IVL should be suspected. Complete one-stage removal of tumors can be performed using cardiopulmonary bypass, and the present patient has shown a favorable outcome.

Female↗
PubMed1997

Increase in heart rate after radiofrequency catheter ablation is mediated by parasympathetic nervous withdrawal and related to site of ablation.

To assess the mechanism for the increased sinus rate after radiofrequency catheter ablation performed for atrioventricular nodal reentrant tachycardia (AVNRT), we studied heart rate variability before and after radiofrequency catheter ablation in 17 patients with AVNRT and in 38 patients with an accessory pathway. The accessory pathway was located at the left ventricular free wall, the right ventricular free wall, or the posterior interventricular septum. An increased sinus rate was observed in patients with AVNRT or with the accessory pathway at the posterior septum or left free wall after radiofrequency ablation. In these groups, high-frequency power, root mean square of successive difference and percent of adjacent cycles that were more than 50 ms apart, all of which are indices reflecting parasympathetic nervous activity, were decreased. The ratio of low-frequency to high-frequency power reflecting sympathovagal balance, was increased in patients with AVNRT or with an accessory pathway at the posterior septum or left free wall. Increases in sinus rate were correlated with decreases in high-frequency power, and percent of adjacent cycles more than 50 ms apart that the increase in heart rate was due to parasympathetic nervous withdrawal.

Adolescent↗
PubMed1997

Increased IL-6 and IL-8 in bronchoalveolar lavage fluids (BALF) from patients with sarcoidosis: correlation with the clinical parameters.

A variety of cytokines have been implicated in the pathogenesis of pulmonary sarcoidosis, but the exact roles of IL-6 and IL-8 are not yet clear. We studied these cytokine levels in BALF from patients with pulmonary sarcoidosis, idiopathic pulmonary fibrosis (IPF), systemic screlosis (SSc) with interstitial lung disease and control subjects. IL-6 and IL-8 levels were significantly elevated in sarcoidosis, IPF and SSc with interstitial lung disease compared with control subjects. Subjects with sarcoidosis had significantly increased levels of both cytokines compared with controls when the cytokine values were corrected by the total albumin content and the two cytokine levels correlated with each other (r = 0.876). BALF IL-6 levels correlated with percent lymphocytes and percent CD3+ cells. Moreover, when sarcoidosis patients were divided into three groups, those who needed steroid therapy or had progressive disease showed increased cytokine levels in BALF over stable or improved patients. These observations suggest that locally derived IL-6 and IL-8 were increased in sarcoidosis and correlated with activity of this granulomatous lung disease.

Adult↗