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Biomedical subjects

H Honda

Publications and source records attributed to H Honda.

At least 181 records · Page 10Linked to original sources
PubMed1998

Optimal MR cholangiopancreatographic sequence and its clinical application.

PURPOSE: To determine the appropriate acquisition parameters for magnetic resonance cholangiopancreatography (MRCP) with a half-Fourier rapid acquisition with relaxation enhancement (RARE) sequence; to determine the optimal MRCP technique by comparing half-Fourier RARE, steady-state free precession (SSFP) two-dimensional (2D) fast spin-echo (SE), and three-dimensional (3D) fast SE sequences; and to clarify the usefulness and limitations of MRCP in diagnosing pancreatic abnormalities. MATERIALS AND METHODS: Half-Fourier RARE MRCP images with varying parameters were compared by using a phantom. Duct conspicuity and contrast-to-noise ratios (C/Ns) were compared for the four MRCP techniques in a phantom and healthy volunteers. The optimal MRCP technique was used to study healthy volunteers and clinical cases. Receiver operating characteristic (ROC) curves were created for data analysis. RESULTS: A 5-mm-thick section without intersection gap was appropriate for half-Fourier RARE MRCP. Only half-Fourier RARE MRCP could depict a 1-mm duct. C/N was the highest with half-Fourier RARE, followed by 3D fast SE, 2D fast SE, and SSFP sequences. ROC curve analysis revealed no interobserver differences, and the area under the curve for detection of strictures of the main pancreatic duct was as high as 0.89. CONCLUSION: Half-Fourier RARE MRCP has the highest contrast and spatial resolution among the four techniques studied and may play an important role in diagnosing pancreatic abnormalities.

Adult↗
PubMed1998

17Beta-estradiol alters isoproterenol-induced relaxation in rat aortic rings.

Female Wistar rats were treated with 17beta-estradiol (E2) (10 microg, s.c.) or with sesame oil for 3 days. The relaxation induced by isoproterenol (10(-9)-3 x 10(-6) M) in aortae precontracted with norepinephrine was significantly suppressed in aortae from E2-treated rats compared with the relaxation in those from control rats. N(G)-Nitro-L-arginine, a nitric oxide synthase inhibitor, inhibited isoproterenol-induced relaxation in aortae from both E2-treated and control rats. Metyrapone, a cytochrome P-450 monooxygenase inhibitor, inhibited it in aortae from control rats, but metyrapone enhanced the maximum relaxation in aortae from E2-treated rats. These results suggest that E2 modulates isoproterenol-induced vasodilation through nitric oxide and cytochrome P-450-dependent metabolites.

Animals↗
PubMed1998

Autoimmune pancreatitis: CT and MR characteristics.

OBJECTIVE: Our goal was to elucidate the CT and MR imaging characteristics in patients with autoimmune pancreatitis, which is a reversible chronic pancreatitis with an autoimmune cause. CONCLUSION: On CT and MR imaging, a capsulelike rim, which is thought to correspond to an inflammatory process involving peripancreatic tissues, appears to be a characteristic finding of autoimmune pancreatitis. Also, diffuse pancreatic enlargement along with hypointensity on T1-weighted MR images and delayed enhancement on dynamic CT and MR studies are other features of this disorder.

Aged↗
PubMed1998

Value of MR cholangiopancreatography in evaluating choledochal cysts.

OBJECTIVE: The aim of this retrospective study was to clarify whether MR cholangiopancreatography (MRCP) is a suitable replacement for ERCP in evaluation of the choledochal cyst. MATERIALS AND METHODS: Sixteen patients (six adult and 10 pediatric) with choledochal cysts underwent MRCP using a half-Fourier acquisition single-shot turbo spin-echo sequence. Extent of the cyst, defects within the biliary tree, and presence or absence of the anomalous junction of the pancreaticobiliary duct were evaluated. Findings were compared with those of ERCP. RESULTS: MRCP better defined the proximal biliary tree than did ERCP in two patients. Defects within the biliary tree were diagnosed correctly on MRCP in eight patients; however, two defects within the distal common bile duct were missed in pediatric patients. The presence of the anomalous junction of the pancreaticobiliary duct was revealed accurately by MRCP in all adult patients but was revealed accurately in only four of the 10 pediatric patients. CONCLUSION: MRCP appears to offer diagnostic information that is equivalent to that of ERCP for assessment of choledochal cysts in adults. In pediatric patients, MRCP should not replace ERCP; however, MRCP can play an important role as a noninvasive examination and should be considered a first-choice imaging technique for evaluation of choledochal cysts.

Adult↗
PubMed1998

[Effect of bisoprolol, a beta 1-selective beta-blocker, on lipid and glucose metabolism and quality of life in elderly patients with essential hypertension].

The present study investigated the effect of bisoprolol, a beta 1-selective beta-blocker without intrinsic sympathomimetic activity (ISA), on lipid and glucose metabolism and quality of life (QOL) in elderly patients with essential hypertention. Bisoprolol at doses of 5-10 mg was administered once daily for 12 weeks to 60 non-elderly and 21 elderly outpatients with mild to moderate essential hypertension. In both groups bisoprolol significantly decreased both systolic and diastolic blood pressures and significantly reduced pulse rates to the same extent. The levels of serum cholesterol, HDL-cholesterol and triglyceride, and the response of plasma glucose and insulin to 75 g oral glucose load, were not changed in either group by the bisoprolol treatment. Bisoprolol significantly improved QOL in both groups. Bradycardia, a side effect attributable to bisoprolol, was noted in only one patient in the elderly group. These results suggest that bisoprolol is a safe and useful antihypertensive drug in elderly and non-elderly patients with essential hypertension.

Adrenergic beta-Antagonists↗
PubMed1998

Establishment, characterization, and chromosomal analysis of new leukemic cell lines derived from MT/p210bcr/abl transgenic mice.

The p210bcr/abl chimeric protein is implicated in the pathogenesis of Philadelphia chromosome-positive human leukemias. Previously, we generated transgenic mice expressing p210bcr/abl by the metallothionein enhancer/promoter (MT/p210bcr/abl) and observed that these mice reproducibly developed T cell leukemia. In this report, we describe the establishment, characterization, and chromosomal analysis of two novel leukemic cell lines derived from MT/p210bcr/abl leukemic mice. Both cell lines carried the transgene and showed the same gene rearrangement patterns as observed in the parental leukemic cells. Expression, tyrosine-phosphorylation, and enhanced kinase activity of the p210bcr/abl were also detected. RT-PCR/SSCP for p53 transcript revealed that one of the cell lines carried a mutation, in contrast to the normal pattern shown by the parental leukemic cells. In addition, the other cell line showed a karyotype of trisomy 15. These results suggest that the p53 mutation and chromosomal abnormality may confer a proliferative ability on leukemic cells in vitro. These new cell lines are considered to be a valuable model not only for examining the biologic properties of p210bcr/abl but also for investigating the malignant process that promotes the proliferation of the leukemic cells expressing p210bcr/abl. Furthermore, these cell lines could be used in therapeutic studies, including adoptive immunotherapy.

Animals↗
PubMed1998

[A case of paraesophageal omental herniation].

A 48-year-old woman underwent routine chest roentgenography and a mass shadow was seen in the posterior mediastinum. CT, MRI and celiac arteriography were performed, and paraesophageal omental herniation was diagnosed. Paraesophageal omental herniation is uncommon, and there have been no reports cases with complications. Therefore, this case is being followed-up carefully.

Celiac Artery↗
PubMed1998

[Intraarterial chemotherapy combined with radiation therapy for advanced cancer of the uterine cervix].

The results of intraarterial chemotherapy (IACT) combined with definitive radiation therapy for 23 advanced and bulky carcinomas of uterine cervix are reported. IA-CT with cisplatin 50 mg and doxorubicin 30 mg was administered by one shot method in bilateral internal iliac arteries. The protocol consisted of one to three treatment session every 3 weeks. Nine of eleven patients with clinical stage III achieved a complete local response (82%), and the 3- and 5-year survival in these cases were 72% and 72%, respectively. These results were superior to the response (58%), 3- and 5-year survivals (68%, 58%) obtained in 19 patients treated mainly with radiation therapy alone. The side effect of grade 2 and 3 for the intestine, such as ileus and hemorrhagic colitis, was noted in 3 patients (15%). In addition, 3 of 8 patients with radical surgery and postoperative radiation therapy after IA-CT developed insufficient fracture of pelvic bone. These complications accompanied by IA-CT combined with radiation therapy and/or surgery increased slightly, compared with that by the previous therapy without IA-CT, but were not critical. The results suggest that IA-CT following radiation therapy is effective to improve the prognosis of patients with Stage III cervical cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

A regional variation of acetylcholine-induced relaxation in different segments of rat aorta.

The tension of the isolated thoracic aorta of the rat was measured isometrically to determine if there is a regional variation of the relaxation to acetylcholine (ACh). Endothelium-derived nitric oxide (NO)-dependent relaxation to ACh in the thoracic aorta precontracted with norepinephrine was significantly greater in the middle and distal segments than in the proximal segments. The relaxation to ACh was inhibited by NG-nitro-L-arginine methyl ester, an inhibitor of NO synthase. The relaxation to the NO donor sodium nitroprusside did not differ between the same three segments of the thoracic aorta. These results suggest that there are regional variations in the ACh-induced release of endothelium-derived NO in the rat thoracic aorta.

Acetylcholine↗
PubMed1997

Isolation of cDNA for an NADP-malic enzyme from Aloe arborescens.

NADP-malic enzyme catalyzes the reaction of decarboxylation from malate. In CAM plants, functions of this enzyme diverged to include both photosynthetic and non-photosynthetic roles. A full length cDNA for an NADP-malic enzyme was isolated from an 'obligate' CAM plant aloe (Aloe arborescens). The cDNA contains an ORF encoding 592 amino acid residues, whose sequence is highly homologous to the known plant NADP-malic enzymes. This gene is constitutively expressed in all organs in a low level. The amount of the transcript exhibited no diurnal variation, suggesting that this gene is not involved in photosynthetic functions.

Aloe↗
PubMed1997

Toxic shock-like syndrome caused by non-group A beta-hemolytic streptococci.

Two patients with rapidly developing shock, multisystem organ failure, and destructive soft-tissue infection caused by groups G and C streptococci are described. Both patients died rapidly despite aggressive treatment. The clinical characteristics cannot be distinguished from those of toxic shock-like syndrome, but Streptococcus pyogenes was not recovered. These strains did not produce any previously identified type of streptococcal pyrogenic exotoxins. These findings suggest that toxic shock-like syndrome can be caused not only by group A but also groups G and C streptococci. The causative strains of toxic shock-like syndrome may have something in common with unknown virulent factors for this syndrome.

Aged↗
PubMed1997

The phosphatidylinositol 3' kinase pathway is required for the survival signal of leukocyte tyrosine kinase.

Leukocyte tyrosine kinase (LTK) is a receptor tyrosine kinase which belongs to the insulin receptor superfamily and is mainly expressed in pre-B lymphocytes and neuronal tissues. Recently, we demonstrated that LTK utilizes Shc and IRS-1 as two major substrates and while both equally activate the Ras pathway, only IRS-1 suppresses apoptosis of hematopoietic cells, suggesting the existence of another unidentified signaling pathway downstream of IRS-1, which is relevant to the anti-apoptotic activity. In the present study, we found that wortmannin, a specific inhibitor of phosphatidylinositol 3' (PI3)-kinase, abolished the survival effects of LTK. Although c-Cbl is found to be phosphorylated by LTK and therefore is a second candidate linking LTK with the PI3-kinase pathway along with IRS-1, we found that the p85 subunit of PI3 kinase directly binds to tyrosine 753 of LTK, which is located within a YXXM motif, a consensus binding amino acid sequence for the SH2 domain of p85, but fails to bind to IRS-1 or c-Cbl. Ba/F3 cells which stably express the EGF receptor-LTK chimeric receptor carrying a mutation at tyrosine 753 fell into apoptotic death even in the presence of EGF, indicating that the PI3 kinase pathway is required for the survival effects of LTK.

Androstadienes↗
PubMed1997

Behavioral and P3 amplitude enhancement in schizophrenia following feedback training.

In order to clarify the remediability of behavioral and electrophysiological abnormalities in schizophrenia, hit rate, reaction time, and P3 amplitude from auditory event-related potentials were evaluated before and after feedback training of a task in 14 schizophrenics and 12 age-matched normal controls. Although mean changes in the three indices due to the training were nonsignificant in both schizophrenic and normal control groups as a whole, the changes in hit rate and reaction time correlated significantly with the P3 amplitude change in the schizophrenic (r = 0.60 and -0.58, respectively) but not in the normal control group. The P3 amplitude change also correlated with the P3 amplitude before the training only in the schizophrenic group (r = -0.68), suggesting that the training was more effective for the schizophrenic patients with marked P3 amplitude reduction. The observed P3 amplitude increase due to training may represent an electrophysiological correlate of a remediable aspect of behavioral deficits in schizophrenics, which may underlie the effectiveness of nonpharmacological treatments.

Adult↗
PubMed1997

Identification of PU.1 and Sp1 as essential transcriptional factors for the promoter activity of mouse tec gene.

Tec is a cytoplasmic protein-tyrosine kinase abundantly expressed in hematopoietic precursor cells. To investigate the mechanism regulating the expression of Tec molecule, we cloned and analysed 5' flanking region of mouse tec gene up to -2kb from the transcriptional initiation site. Luciferase assays using successive deletion mutants demonstrated that regions from -364 to -323 and from -122 to -63, which contain the consensus binding sequences for PU.1 (GGAA) and Sp1 (GGGCGG), respectively, are important for the transcriptional activity. Gel-shift and supershift assays revealed that PU.1 and Sp1 bind to the these regions through their consensus binding motifs. In addition, introduction of mutations into these motifs resulted in marked decrease in the promoter activity. These results indicate that PU.1 and Sp1 are essential for the transcriptional activity of the tec promoter and suggest that the cooperation of PU.1 and Sp1 plays a substantial role in the preferential expression of the Tec molecule in the hematopoietic lineages.

Animals↗
PubMed1997

Antisense repression of proto-oncogene c-Cbl enhances activation of the JAK-STAT pathway but not the ras pathway in epidermal growth factor receptor signaling.

Many growth factors including epidermal growth factor (EGF) induce tyrosine phosphorylation of the c-Cbl proto-oncogene product, whose function, however, remains unclear. Recently, Sli-1, a Caenorhabditis elegans homologue of c-Cbl, was found to be a negative regulator of let-23-mediated vulval induction pathway, suggesting that c-Cbl may negatively regulate EGF receptor (EGFR)-mediated signaling. In this study, by an antisense RNA approach, we examined the effects of expression level of c-Cbl on EGFR signaling and showed that overexpression of c-Cbl reduces and antisense repression of c-Cbl enhances autophosphorylation of EGF receptors and activation of the JAK-STAT pathway. However, in contrast to the Sli-1 protein, the expressed amount of c-Cbl does not affect activation of the Ras pathway, suggesting that the EGFR-mediated signaling pathways are differently regulated by c-Cbl among nematodes and mammals.

3T3 Cells↗
PubMed1997

Modification of human left ventricular relaxation by small-amplitude, phase-controlled mechanical vibration on the chest wall.

BACKGROUND: Direct clinical manipulation to improve an impairment of left ventricular (LV) relaxation has not been reported. We investigated whether the LV relaxation rate in humans could be modulated by phase-controlled mechanical vibration applied to the patient's anterior chest wall and whether there are some quantitative differences in the responses of normal (N), hypertrophied (H), and failing (F) ventricle. METHODS AND RESULTS: In 46 patients (N, 10; H, 18 [hypertrophic cardiomyopathy]; F, 18 [heart failure]), the vibrator was attached to the precordium and a 50-Hz, 2-mm sinusoidal mechanical vibration was applied, with the timing restricted from the onset of isovolumic relaxation to end-diastole during cardiac catheterization. Heart rate and peak LV pressure showed no difference with vibration. However, in all patients, precordial vibration caused an acceleration of the LV pressure fall. The magnitude of the induced reduction of the time constant of LV pressure decay (delta T) was larger (P < .01) in H and F than in N (4.6 +/- 2.3, 4.0 +/- 1.6, and 0.6 +/- 1.5 ms for H, F, and N, respectively). Delta T correlated strongly with the magnitude of impaired relaxation and the magnitude of transmitted vibration to the ventricle. CONCLUSIONS: Phase-controlled, small-amplitude vibration on the chest wall can directly modulate LV relaxation rate, especially in those with hypertrophy or failing ventricle.

Adult↗
PubMed1997

Expression of Fas antigen is not associated with apoptosis in human myopathies.

To determine whether the Fas-Fas-ligand mediated apoptosis occurs in the pathologic process of human muscle diseases, we examined the expression of Fas antigen, Fas-ligand messenger RNA, and chromosomal DNA fragmentation in the muscle cells of patients with a variety of human muscle disorders. The present study demonstrated that the Fas antigen of a whole molecule was expressed on the muscle fibers of patients with muscle wasting diseases. However, the apoptotic process did not occur in the muscle cells, and there was no evidence of Fas-ligand synthesis in the diseased muscle tissue. Our data suggest that the expression of Fas antigen on fibers in diseased muscle is related to unknown biological functions other than "apoptosis" in the process of muscle fiber injury.

Adult↗