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T Takenaka

Publications and source records attributed to T Takenaka.

At least 37 records · Page 2Linked to original sources
PubMed2001

Scattering of a Hermite-Gaussian beam field by a chiral sphere.

Scattering of a Hermite-Gaussian beam field by a chiral sphere is analyzed. A Hermite-Gaussian beam field is expressed as a superposition of multipole fields at complex-source points. Electromagnetic fields are expanded in terms of the spherical vector wave functions. The unknown expansion coefficients for the scattered field and the internal field are determined by the boundary conditions. As numerical examples, the scattered near fields of the beam incidence are calculated, and the effects of the chirality and the radius of the chiral sphere on the fields are examined. The results for a Gaussian beam incidence are also compared with those of a plane-wave incidence.

Journal Article↗
PubMed2001

[Effects of adjuvants on the function of antigen presenting cells in the production of IgE in mice].

In an examination of the effects of adjuvants on the production of IgE, amounts of mRNAs for cytokines in antigen presenting cells(APCs) were assayed by RT-PCR and expressions of surface molecules on the cells were analyzed by flowcytometry when primed with antigen plus adjuvant. When mice were primed with ovalbumin plus alum, the levels of total and specific IgE were higher than those of mice primed with ovalbumin plus CFA. The APCs from mice primed with ovalbumin plus alum expressed higher levels of IL-1 mRNA than those in APCs from mice primed with ovalbumin plus CFA. B7 molecules were more expressed on the surface of the APCs from mice primed with ovalbumin plus CFA. The results suggested that these modulations of the functions of APCs affected the induction of helper T cell subsets in mice primed with different adjuvant.

Adjuvants, Immunologic↗
PubMed2000

Long-term enzyme correction and lipid reduction in multiple organs of primary and secondary transplanted Fabry mice receiving transduced bone marrow cells.

Fabry disease is a compelling target for gene therapy as a treatment strategy. A deficiency in the lysosomal hydrolase alpha-galactosidase A (alpha-gal A; EC ) leads to impaired catabolism of alpha-galactosyl-terminal lipids such as globotriaosylceramide (Gb3). Patients develop vascular occlusions that cause cardiovascular, cerebrovascular, and renal disease. Unlike for some lysosomal storage disorders, there is limited primary nervous system involvement in Fabry disease. The enzyme defect can be corrected by gene transfer. Overexpression of alpha-gal A by transduced cells results in secretion of this enzyme. Secreted enzyme is available for uptake by nontransduced cells presumably by receptor-mediated endocytosis. Correction of bystander cells may occur locally or systemically after circulation of the enzyme in the blood. In this paper we report studies on long-term genetic correction in an alpha-gal A-deficient mouse model of Fabry disease. alpha-gal A-deficient bone marrow mononuclear cells (BMMCs) were transduced with a retrovirus encoding alpha-gal A and transplanted into sublethally and lethally irradiated alpha-gal A-deficient mice. alpha-gal A activity and Gb3 levels were analyzed in plasma, peripheral blood mononuclear cells, BMMCs, liver, spleen, heart, lung, kidney, and brain. Primary recipient animals were followed for up to 26 weeks. BMMCs were then transplanted into secondary recipients. Increased alpha-gal A activity and decreased Gb3 storage were observed in all recipient groups in all organs and tissues except the brain. These effects occurred even with a low percentage of transduced cells. The findings indicate that genetic correction of bone marrow cells derived from patients with Fabry disease may have utility for phenotypic correction of patients with this disorder.

Animals↗
PubMed2000

Interleukin-12 promotes neurite outgrowth in mouse sympathetic superior cervical ganglion neurons.

To determine the role of cytokines in the nervous system, we examined the effect of interleukin-12(IL-12) on the nerve regeneration of mouse superior cervical ganglion cells (SCG). IL-12 enhanced the neurite outgrowth in a concentration-dependent manner. Immunocytochemical studies demonstrated the expression of IL-12 receptors in neuronal bodies and neurites. The mRNA expression of IL-12 receptors in SCG cells was confirmed by reverse transcription-polymerase chain reaction. Our data demonstrated the presence of IL-12 receptors in sympathetic neurons and suggest that IL-12 plays an important role in neuronal regeneration.

Animals↗
PubMed2000

Acetylcholine- and ergonovine-induced coronary microvascular spasm reflected by increased coronary vascular resistance and myocardial lactate production.

Diagnosis of coronary microvascular spasm remains largely speculative because it has been mostly based on chest pain and electrocardiographic ST-segment shift with slow filling of contrast medium into the coronary artery. A patient with resting chest pain and normal coronary angiograms underwent provocative tests with intracoronary acetylcholine (ACh) and ergonovine. During the tests, coronary diameter and flow velocity in the left anterior descending (LAD) coronary artery were measured with quantitative coronary angiography and intracoronary Doppler guide wire, respectively. Vascular resistance of the LAD and lactate production were determined separately. With injections of 100 microg of ACh and 20 microg of ergonovine, chest pain occurred with ST-segment elevation in the precordial leads in the absence of epicardial coronary spasm. Coronary vascular resistance increased by 2.2- and 1.6-fold of the baseline value with ACh and ergonovine, respectively. Myocardial lactate production was noted during the ST-segment elevation. Coronary microvascular spasm was verified by the increment in coronary vascular resistance and myocardial lactate production with concomitant ST-segment elevation in the presence of normal coronary angiograms.

Acetylcholine↗
PubMed2000

Prostaglandin E(2) enhances axonal transport and neuritogenesis in cultured mouse dorsal root ganglion neurons.

The effects of prostaglandin E(2) on axonal transport in cultured mouse dorsal root ganglion neurons were investigated by analysing the number of axonally transported particles under video-enhanced microscopy. Application of prostaglandin E(2) increased the number of particles transported in anterograde and retrograde directions. The EP(2) prostaglandin receptor agonist butaprost mimicked the effect of prostaglandin E(2), but the EP(1)/EP(3) prostaglandin receptor agonist 17-phenyl trinor prostaglandin E(2) and the EP(3) prostaglandin receptor agonist M&B 28767 had no effect. The membrane-permeable cyclic AMP analogue dibutyryl cyclic AMP and the adenylate cyclase activator forskolin mimicked the effect of prostaglandin E(2). The protein kinase A inhibitor H-89 reversibly reduced the number of particles in both anterograde and retrograde directions. The effects of prostaglandin E(2) and dibutyryl cyclic AMP were blocked by H-89. Taken together with previous biochemical studies showing that prostaglandin E(2) increases cyclic AMP levels, the present results suggest that prostaglandin E(2) enhances axonal transport via the EP(2) receptor and cyclic AMP-dependent protein kinase A pathway. We further investigated the role of prostaglandin E(2) in neurite growth. Prostaglandin E(2) increased both the number of cells exhibiting neurites and the neurite growth rate, operating by a similar mechanism to stimulation of axonal transport. Prostaglandin E(2) may modulate axonal transport to supply materials for morphogenesis as well as other functions in sensory neurons.

Animals↗
PubMed2000

Role of protein kinase C in angiotensin II-induced constriction of renal microvessels.

UNLABELLED: Role of protein kinase C in angiotensin II-induced constriction of renal microvessels. BACKGROUND: Although angiotensin II (Ang II) exerts its action through multiple vasomotor mechanisms, the contribution of phosphoinositol hydrolysis products to Ang II-induced renal vasoconstriction remains undetermined. METHODS: The role of protein kinase C (PKC) in Ang II-induced afferent (AFF) and efferent (EFF) arteriolar constriction was examined using the isolated perfused hydronephrotic rat kidney. RESULTS: Ang II (0.3 nmol/L)-induced EFF constriction was refractory to inhibition of voltage-dependent calcium channels by pranidipine (1 micromol/L, 19 +/- 2% reversal) but was completely reversed by a PKC inhibitor, chelerythrine (1 micromol/L, 96 +/- 2% reversal). Furthermore, direct PKC activation by phorbol myristate acetate (PMA; 1 micromol/L) caused prominent EFF constriction, and this constriction was inhibited by manganese and free calcium medium. In contrast, Ang II-induced AFF constriction was completely abolished by pranidipine (98 +/- 4% reversal) and was partially inhibited by chelerythrine (55 +/- 3% reversal). Although PMA elicited marked AFF constriction, this constriction was insensitive to the calcium antagonist, but was totally inhibited by manganese or free calcium medium. CONCLUSIONS: PKC plays an obligatory role in Ang II-induced EFF constriction that requires extracellular calcium entry through nonselective cation channels. In contrast, in concert with our recent findings demonstrating a complete dilation by thapsigargin, Ang II-induced AFF constriction is mainly mediated by inositol trisphosphate (IP3) and voltage-dependent calcium channel pathways, but could not be attributed to the PKC-activated calcium entry pathway (for example, nonselective cation channels). Rather, Ang II-stimulated PKC may cross-talk to the IP3/voltage-dependent calcium channel pathway and could modulate the vasoconstrictor mechanism of the AFF. Thus, the role of PKC during Ang II stimulation differs in AFF and EFF, which may constitute segmental heterogeneity in the renal microvasculature.

Angiotensin II↗
PubMed2000

Influence of the timing of initiating antihypertensive therapy in hypertensive rats with renal failure.

The important contribution of hypertension to the progression of renal failure is well realized. However, it have been less discussed which drugs are suitable for the different stages of progressive renal failure. The present study examined the effects of timing of antihypertensive therapy using calcium channel blocker and angiotensin converting enzyme inhibitor in 5/6 nephrectomized spontaneously hypertensive rats (SHRs). Forty male 6 week old SHRs were divided into 5 groups (n=8 in each group), and they were placed on a high salt diet after 5/6 nephrectomy. Group 1, high salt diet without any drug. Group 2 received 0.2 mg/kg/day of amlodipine and group 3 received 0.2 mg/kg/day of enalapril mixed in the high salt diet from week 6 respectively. Similarly group 4 received the same doses of amlodipine, and group 5 received the same doses of enalapril from week 10. Each drug protected from increasing blood pressure in 4 groups, and no significant difference was observed between the effects of amlodipine and enalapril. Proteinuria was reduced with both drugs. In histopathological evaluation, glomerulosclerosis was controlled only in group 2, and arterio/olosclerosis was significantly suppressed in all treated groups except group 5. From these results, both amlodipine and enalapril are renal protective in early stage of renal failure with hypertension. However, in advanced stage of renal failure, amlodipine is superior in its renal protective effect.

Amlodipine↗
PubMed2000

Alternating combination chemotherapy C-MOPP (cyclophosphamide, vincristine, procarbazine, prednisone) and ABVd (adriamycin, bleomycin, vinblastine, dacarbazine) in clinical stage II-IV Hodgkin's disease: a multicenter phase II study (JCOG 8905). The Lymphoma Study Group of the Japan Clinical Oncology Group.

BACKGROUND: The main form of cytotoxic treatment for advanced Hodgkin's disease (HD) is conventional dose multiagents chemotherapy. As HD is not common in Japan, we conducted a phase II study of the commonly used combination chemotherapy (CCT) regimen established in the West for Japanese patients with advanced HD to confirm the efficacy and safety. METHOD: Between October 1989 and February 1993, a multicenter phase II study of alternating CCT C-MOPP (cyclophosphamide, vincristine, procarbazine, prednisone) and ABVd (adriamycin, vinblastine, bleomycin, dacarbazine) to evaluate its clinical usefulness for clinical stage (cS) II-IV HD was conducted by the Lymphoma Study Group of the Japan Clinical Oncology Group. RESULTS: Seventy-nine previously untreated patients were enrolled in the study. For 67 eligible patients, the response rate was 92.5% with 83.6% complete response (CR). For 40 cS II and 27 cS III/IV patients the response rate was 95.0% with 90.0% CR and 88.9% with 74.1% CR, respectively. The overall 5-year survival rate was 84.8%. Those of cS II and cS III/IV were 92.5 and 73.1%, respectively. There was no significant difference between cS II and cS III/IV (p = 0.1025). The progression-free 4-year survival rate was 72.8%. Those of cS II and cS III/IV were 77.5 and 65.7%, respectively. There was no significant difference between cS II and cS III/IV (p = 0.2483). Grade 4 toxicity by the criteria of the World Health Organization consisted of leukocytopenia in 28.4% of patients. There was GPT elevation in 4.5%, nausea/vomiting in 11.9% and CNS in 1.5% of patients, but there was no treatment-related death. CONCLUSION: The C-MOPP/ABVd regimen for Japanese patients with advanced HD is considered to be one of the effective CCTs according to the results of the present phase II study.

Adolescent↗
PubMed2000

Role of leukocytes in radicular pain secondary to herniated nucleus pulposus.

Some studies have assessed inflammatory cells such as macrophages, lymphocytes, and neutrophils in herniated lumbar disc tissues using histologic analysis. However, there is no consensus regarding the relationships between clinical symptoms, including radicular pain and the presence of inflammatory cells. It has been shown that autologous nucleus pulposus relocated on the lumbar nerve root in rats produces time dependent and reversible mechanical hyperalgesia, which is thought to be a pain related behavior in peripheral neuropathic pain models. The purpose of this study was to determine whether leukocytes play a role in the mechanical hyperalgesia induced by the nucleus pulposus and to characterize the role of leukocytes in radicular pain attributable to lumbar disc herniation. Nitrogen mustard was used to induce and evaluate leukocytopenia in rats. Sensitivity to mechanical noxious stimuli was measured quantitatively, and inflammatory cells in granulation tissue around the nerve root were examined histologically. The nucleus pulposus produced neither mechanical hyperalgesia nor abundant inflammatory cells in rats with nitrogen mustard induced leukocytopenia. Neuropathic pain produced by the nucleus pulposus, when placed on the nerve root, may be related to inflammatory cell infiltration induced by relocation of the nucleus pulposus, rather than the nucleus pulposus itself.

Animals↗
PubMed2000

Osteopontin expressed by renal tubular epithelium mediates interstitial monocyte infiltration in rats.

In this study, we have shown that intravenously administered antisense oligodeoxynucleotide (ODN) was demonstrated to be taken up by tubular epithelium, after which it blocked mRNA expression of target genes in normal and nephritic rats. Therefore, we injected osteopontin (OPN) antisense ODN to Goodpasture syndrome (GPS) rats every second day between days 27 and 35, the time when renal OPN expression increased and interstitial monocyte infiltration was aggravated. In parallel to blockade of tubular OPN expression, this treatment significantly attenuated monocyte infiltration and preserved renal plasma flow in GPS rats at day 37, compared with sense ODN-treated and untreated GPS rats. No significant changes were observed in OPN mRNA level by RT-PCR and histopathology of the glomeruli after ODN treatment, which was compatible with an absence of differences in the urinary protein excretion rate. In conclusion, OPN expressed by tubular epithelium played a pivotal role in mediating peritubular monocyte infiltration consequent to glomerular disease.

Animals↗
PubMed2000

Evolution of left ventricular involvement in arrhythmogenic right ventricular cardiomyopathy.

Left ventricular (LV) involvement in arrhythmogenic right ventricular cardiomyopathy (ARVC) is fairly well known, but the evolution of LV involvement during long-term follow-up has not been well documented. We describe such evolution in a patient followed for 9 years. Evolution was confirmed by a progressive perfusion defect of the LV wall in myocardial scintigrams and by the development of LV asynergy with ventricular aneurysm formation in left ventriculograms. As the right ventricle progressively enlarged, we concluded that ARVC is a diffuse and progressive myocardial disease that affects both ventricles.

Adult↗
PubMed2000

Chronic use of continuous dosing of long-term nitrates does not prevent cardiac events in patients with severe acute myocardial infarction.

This study was performed to investigate the effects of the chronic use of continuous, not eccentric, dosing of nitrates on cardiac events in patients with severe acute myocardial infarction. A total of 1,303 patients with healed myocardial infarction were divided into two groups: treatment with nitrates or nontreatment. Primary end points were nonfatal and fatal recurrent myocardial infarction, death from congestive heart failure and sudden death. Among the 725 patients treated with nitrates, 45 patients (6.2%) experienced cardiac events during the observation period, whereas only 17 of the 578 patients treated without nitrates (2.9%) had cardiac events. This difference was statistically significant (p < 0.01; odds ratio 2.18, 95% confidence interval 1.24-3.86). In Killip class II-IV patients, the incidence of cardiac events in patients with nitrates was significantly greater than in patients without nitrates (18.8 vs. 3.5%, p < 0.05). The chronic use of continuous, not eccentric, dosing of nitrates did not prevent cardiac events in patients with severe acute myocardial infarction.

Acute Disease↗
PubMed2000

Coronary artery-left ventricle fistula complicating balloon angioplasty--a case report.

The authors describe a coronary artery fistula complicated balloon angioplasty. The proximal left anterior descending coronary artery was dilated, but a septal branch was occluded by thrombus. Angioplasty was used on the septal branch, but a pseudoaneurysm communicating with the left ventricle occurred. Follow-up angiography revealed spontaneous closure of the fistula.

Aged↗
PubMed2000

Retrospective analysis showing less cardiac events in post-myocardial infarction patients treated with metoprolol. Secondary Prevention Group.

This analysis was carried out to clarify the capacity of metoprolol to prevent cardiac events in Japanese post-myocardial infarction patients during a follow-up period of 16.3 months. Cardiac events occurred in 44 of 650 patients treated without beta-blockers (6.8%) and in 13 of 432 patients treated with metoprolol (3.0%), which represents a significant decline in the incidence of cardiac events among patients receiving metoprolol (p<0.01, odds ratio 0.43, 95% confidence interval 0.23-0.80). Because this was a retrospective analysis, there were unavoidable differences in the backgrounds of the patients in the 2 groups. Subgroup analyses, each focusing on a specific patient characteristic, were therefore performed. These showed that metoprolol effectively reduced cardiac events in many subgroups. Furthermore, multivariate analysis carried out to exclude any modification based on the differences in patient background confirmed metoprolol to be effective in reducing subsequent cardiac events in post-myocardial infarction patients. A large, randomized, placebo-controlled clinical trial needs to be performed in the Japanese population to confirm the present result.

Adrenergic beta-Antagonists↗
PubMed2000

Effect of celiprolol on cardiac hypertrophy in hypertension.

The present study was undertaken to clarify whether celiprolol and atenolol, beta1-selective beta blockers with and without intrinsic sympathomimetic activity (ISA), respectively, might improve ischemic damage in the isolated perfused hearts of spontaneously hypertensive rats (SHR), and whether long-term treatment with celiprolol may reduce left ventricular hypertrophy (LVH) in patients with essential hypertension. Atenolol (50 mg/kg/day) or celiprolol (300 mg/kg/day) for 7 weeks significantly reduced the blood pressure in SHR to the same degree, and both drugs decreased the heart rate, but the magnitude of the fall in heart rate was significantly higher with atenolol treatment than with celiprolol treatment. Both treatments significantly reduced the ratio of LV weight to body weight in SHR and significantly improved the coronary reserve in SHR to the same extent. Both treatments significantly improved the extent of recovery of the pressure-rate product and the extent of percent recovery of the coronary flow after reperfusion following 30 min of ischemia in SHR. Celiprolol treatment in patients with essential hypertension for 12 months significantly decreased interventricular septal thickness (IVST)+LV posterior wall thickness (PWT) and LV mass index (LVMI), but there was no significant correlation between IVST+PWT or LVMI and blood pressure before and after treatment. IVST+PWT and LVMI were significantly decreased after 3 months of treatment and these LVH indices were significantly smaller after 6 and 12 months of treatment than after 3 months of treatment. In conclusion, both celiprolol and atenolol treatment reduced LVH and improved the ischemic damage in SHR. In essential hypertensive patients with LVH, celiprolol treatment effectively reduced blood pressure and achieved LVH regression.

Adrenergic beta-Antagonists↗