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Biomedical subjects

H Miyamoto

Publications and source records attributed to H Miyamoto.

At least 127 records · Page 7Linked to original sources
PubMed1999

[Intralobar pulmonary sequestration presenting increased serum CEA, CA 19-9, and CA 125, and associated with asymptomatic pulmonary aspergillosis].

A 44-year-old woman was admitted to our hospital for further evaluation of a consolidated shadow in the left lower lobe and the evaluation of serum tumor markers (CEA 46.3 ng/ml, CA 19-9 1911 U/ml, and CA 125 103 U/ml). Chest computed tomography revealed an irregular shaped, low density mass shadow in the left S10 region, suggesting the diagnosis of pulmonary sequestration or bronchial atresia. However digital subtraction angiography failed to demonstrate an anomalous feeding artery. We could not rule out the possibility that a malignant lesion was included in the consolidated shadow. A left thoracotomy revealed an intralobar pulmonary sequestration of the left lower lobe. Hyphae of aspergillus were found in the lumen of the cystic bronchus of the resected lung. Immunohistochemical studies showed strong expression of CEA, CA 19-9, and CA 125 by bronchial epithelia in the pulmonary sequenstration. The serum values of tumor markers returned to their normal ranges after surgery.

Adult↗
PubMed1999

[Percutaneous transluminal coronary angioplasty for restenosis following Palmaz-Schatz stenting: larger size balloons are more effective?].

Intracoronary stenting reduces the restenosis rate after percutaneous transluminal coronary angioplasty (PTCA). However, restenosis still occurs in 20% to 30% of patients after stenting. Management of in-stent restenosis has become a significant challenge in interventional cardiology. The efficacy of re-PTCA with a larger balloon was investigated for restenosis following Palmaz-Schatz stenting. Clinical and angiographic results were compared in 46 consecutive patients with in-stent restenosis after one Palmaz-Schatz stenting. Twenty patients underwent redilation with a slightly larger balloon than used at the stenting (Large group) and 26 underwent redilation with the same size balloon as at the stenting (Control group). The clinical factors, lesion characteristics, lesion length, reference diameter and minimal luminal diameter at re-PTCA for the in-stent restenosis did not differ significantly between the 2 groups. Minimal luminal diameter of the Large group after re-PTCA was significantly larger than that of the Control group (3.1 +/- 0.2 vs 2.9 +/- 1.2 mm, p < 0.05). Follow-up angiography showed that the minimal luminal diameter of the Large group was significantly larger (2.1 +/- 0.6 vs 1.7 +/- 0.6 mm, p < 0.05) and the re-restenosis rate of Large group tended to be lower than that of the Control group (15% vs 38%, p = 0.07). Re-PTCA for in-stent restenosis with a slightly larger balloon than used at the stenting reduces the re-restenosis rate.

Aged↗
PubMed1999

Targeted delivery of anti-angiogenic agent TNP-470 using water-soluble polymer in the treatment of choroidal neovascularization.

PURPOSE: The conjugation of drugs with water-soluble polymers such as poly(vinyl alcohol) (PVA) tends to prolong the half-life of drugs and facilitate the accumulation of drugs in tissues involving neovascularization. The purpose of this study was to evaluate the effect of TNP-470-PVA conjugate on the proliferation of endothelial cells in vitro and on experimental choroidal neovascularization (CNV) in vivo. METHODS: TNP-470 was conjugated in PVA by a dimethylaminopyridine-catalyzed reaction. The effects of TNP-470-PVA and free TNP-470 on the proliferation of human umbilical vein endothelial cells (HUVECs) and bovine retinal pigment epithelial cells (BRPECs) were evaluated by the tetrazolium-based colorimetric assay (XTT assay). Experimental CNV was induced by subretinal injection of gelatin microspheres containing basic fibroblast growth factor, into rabbits. Thirty rabbits were intravenously treated either with TNP-470-PVA (n = 8), free TNP470 (n = 5), free PVA (n = 5), or saline (n = 12) daily for 3 days, 2 weeks after implantation of gelatin microspheres. Fluorescein angiography was performed to detect the area with CNV, and the evaluation was made by computerized measurement of digital images. These eyes were also examined histologically. To observe the accumulation of conjugate, 3 rabbits with CNV received rhodamine B isothiocyanate-binding PVA (RITC-PVA), and the lesion was studied 24 hours later by fluorescein microscopy. RESULTS: The TNP-470-PVA inhibited the growth of HUVECs, similar to that of free TNP-470. The BRPECs were less sensitive to TNP-470-PVA than were the HUVECs. TNP-470-PVA significantly inhibited the progression of CNV in rabbits (P = 0.001). Histologic studies at 4 weeks after treatment demonstrated that the degree of vascular formation and the number of vascular endothelial cells in the subretinal membrane of the eyes treated with TNP-470-PVA were less than those of the control eyes. RITC-PVA remained in the area with CNV 24 hours after administration. CONCLUSIONS: These results suggest that TNP-470-PVA inhibited the proliferation of HUVECs more sensitively than that of BRPECs, and the targeted delivery of TNP-470-PVA may have potential as a treatment modality for CNV.

Animals↗
PubMed1999

[Is Palmaz-Schatz stenting effective for second restenosis?].

The long-term outcome after coronary stent placement in restenotic lesions after balloon angioplasty (percutaneous transluminal coronary angioplasty: PTCA)may be less favorable compared to stent treatment of de novo lesions, but the role of stents in restenotic lesions after 2 prior PTCA procedures is unknown. Elective Palmaz-Schatz stent placement was performed in 124 consecutive patients. Stents were placed in 70 patients(56%) in the native coronary arteries for de novo lesions(de novo group), in 33 patients (27%)for restenotic lesions after one prior PTCA(restenosis group), and 21 patients(17%)for restenotic lesions after 2 prior PTCA(second restenosis group). The 3 groups were well matched with respect to lesion type, lesion length, and reference diameter. Stent size was similar in the 3 groups. Follow-up angiograms taken about 6 months after stenting were available for all patients. The restenosis rate after stenting was similar for the de novo group and restenosis group(19% vs 27%, NS). The second restenosis group tended to have a higher restenosis rate after stenting than the de novo group(38% vs 19%, p = 0.06). The frequency of diffuse type in-stent restenosis of the second restenosis group tended to be higher than that of the de novo group(63% vs 13%, p = 0.08). Our results suggest that the restenosis rate after stenting was higher in patients with repeated restenosis. Therefore, other therapeutic methods should be considered.

Angioplasty, Balloon, Coronary↗
PubMed1999

[An analysis of nutritional status and pulmonary hypertension in patients with sequela of pulmonary tuberculosis and chronic obstructive pulmonary disease].

The prognostic value of hypercapnia and/or pulmonary hypertension differs in patients with sequela of pulmonary tuberculosis (TBseq) and those with chronic obstructive pulmonary disease (COPD) who are receiving home oxygen therapy (HOT). In an attempt to identify the factors, if any, that might explain this difference, we first compared nutritional status, respiratory function test results, dyspnea indexes, and other data for hypercapnic patients (PaCO2 > or = 45 Torr) and normocapnic patients (PaCO2 < 45 Torr) receiving HOT. Second, we examined the relationship between the degree of pulmonary hypertension and several respiratory function parameters for patients in each disease category. In 44 patients with TBseq, nutritional status estimated by body mass index and serum albumin was significantly better in the hypercapnic patients than in the normocapnic patients. However, this difference was not observed in 37 patients with COPD. In 30 patients with TBseq, the degree of pulmonary hypertension correlated significantly only with PaO2; in 32 patients with COPD, however, significant correlations were observed not only with PaO2 but also with PaCO2, %VC, and FEV1. These differences distinguishing groups of patients with the 2 diseases may provide an explanatory basis for the difference in prognostic value of hypercapnia and/or pulmonary hypertension in patients receiving HOT.

Aged↗
PubMed1999

[Acute respiratory failure caused by inhalation of waterproofing spray fumes].

A 25-year-old woman was admitted to our hospital because of dry cough, slight fever, and severe dyspnea 5 hrs after inhalation of waterproofing spray. She had used the spray indoors near an oil heater, and then had smoked with spray-contaminated fingers. Chest roentgenograms revealed diffuse interstitial shadows mixed with patchy alveolar infiltration, and computed tomographic (CT) scans confirmed diffuse infiltration in both lungs. Marked leukocytosis and severe hypoxemia were noted. A transbronchial lung biopsy performed 4 days later demonstrated extensive alveolitis characterized by edema in alveolar septa and marked neutrophil migration into alveoli as well as alveolar septa. Oxygen therapy and the administration of methylprednisolone (1 g/day) achieved a complete recovery in about 1 week. We speculated that acute lung injury in this patient may have been induced by direct inhalation not only of the waterproofing spray itself, but also of spray by-products resulting from heat-decomposition. When using waterproofing spray, precautions should be taken to avoid inhaling the spray fumes or the more toxic by-products of thermal degradation.

Acute Disease↗
PubMed1998

Effects of a time-varying strong magnetic field on transient increase in cytosolic free Ca2+ induced by bradykinin in cultured bovine adrenal chromaffin cells.

We tested the effects of exposure to a time-varying magnetic field changing between 0.07 and 1.7 T at an interval of 3 s on transient increase in intracellular Ca2+ stimulated by bradykinin in bovine adrenal chromaffin cells. Addition of bradykinin induced the increase in intracellular Ca2+ within a few minutes. The exposure to the magnetic field perfectly suppressed the increase in intracellular Ca2+ in Ca2+-free medium. The inhibition occurred for 15 min when the maximum magnetic flux density was more than 1.4 T. These results suggest that the exposure inhibits Ca2+ release from intracellular Ca2+ stores.

Animals↗
PubMed1998

Delta5-androstenediol is a natural hormone with androgenic activity in human prostate cancer cells.

It is known that androst-5-ene-3beta,17beta-diol (Adiol), a precursor of testosterone (T), can activate estrogen target genes. The androgenic activity of Adiol itself, however, is poorly understood. Using a transient transfection assay, we here demonstrate in human prostate cancer cells that Adiol can activate androgen receptor (AR) target genes in the presence of AR, and that AR coactivator ARA70 can further enhance this Adiol-induced AR transcriptional activity. In contrast to this finding, an active metabolite of dehydroepiandrosterone, 7-oxo-dehydroepiandrosterone, does not activate AR target gene in the absence or presence of ARA70. Thin layer chromatography analysis reveals that T, dihydrotestosterone, and 17beta-estradiol are undetectable in human prostate cancer DU145 cells after treatment with Adiol. Additionally, a proteolysis assay shows that a distinct ligand-receptor conformational difference exists between T-AR and Adiol-AR. Together, the above findings and the fact that T, but not Adiol, can induce transcriptional activity in a mutant AR (mtAR708), suggest that, without being metabolized into T, Adiol itself may represent a natural hormone with androgenic activity in human prostate cancer cells. Because two potent antiandrogens, hydroxyflutamide (Eulexin), and bicalutamide (casodex), that are widely used for the treatment of prostate cancer, fail to block Adiol-mediated induction of AR transcriptional activity in prostate cancer cells, the effectiveness of so-called "total androgen blockage," a standard treatment for prostate cancer, may need to be reevaluated.

Androgens↗
PubMed1998

Retinoblastoma, a tumor suppressor, is a coactivator for the androgen receptor in human prostate cancer DU145 cells.

The retinoblastoma protein may function as a tumor suppressor by controlling the progression of the normal cell cycle. Inactivation of Rb has been regarded as an important event in prostate carcinogenesis. However, the detailed mechanism of how Rb is linked to androgen-androgen receptor (A-AR), the major factor in promotion of prostate tumor growth, remains unclear. Using GST-Rb pull down assay and mammalian two-hybrid system, we report here that Rb can bind specifically to AR in an androgen-independent manner. Transient transfection assay demonstrates that cotransfection of AR and Rb can further induce AR transcriptional activity 4-fold in the presence of 1 nM dihydrotestosterone in DU145 cells. Interestingly, cotransfection of Rb and ARA70, the first identified AR coactivator, with AR can additively induce AR transcriptional activity 13-fold (from 5-fold to 64-fold). In conclusion, our discovery that Rb can function as a coactivator to induce AR transcriptional activity in prostate cells may represent the first data to link a negative growth regulatory protein function in a positive manner, by inducing the transcriptional activity of AR.

Cell Cycle↗
PubMed1998

Promotion of agonist activity of antiandrogens by the androgen receptor coactivator, ARA70, in human prostate cancer DU145 cells.

Although hormone therapy with antiandrogens has been widely used for the treatment of prostate cancer, some antiandrogens may act as androgen receptor (AR) agonists that may result in antiandrogen withdrawal syndrome. The molecular mechanism of this agonist response, however, remains unclear. Using mammalian two-hybrid assay, we report that antiandrogens, hydroxyflutamide, bicalutamide (casodex), cyproterone acetate, and RU58841, and other compounds such as genistein and RU486, can promote the interaction between AR and its coactivator, ARA70, in a dose-dependent manner. The chloramphenicol acetyltransferase assay further demonstrates that these antiandrogens and related compounds significantly enhance the AR transcriptional activity by cotransfection of AR and ARA70 in a 1:3 ratio into human prostate cancer DU145 cells. Our results suggest that the agonist activity of antiandrogens might occur with the proper interaction of AR and ARA70 in DU145 cells. These findings may provide a good model to develop better antiandrogens without agonist activity.

Androgen Antagonists↗
PubMed1998

From estrogen to androgen receptor: a new pathway for sex hormones in prostate.

While all three coactivators ARA70, steroid receptor coactivator 1, and RAC3/ACTR can enhance androgen receptor (AR) transcriptional activity at 1 nM dihydrotestosterone, we here demonstrate that only ARA70 can induce AR transcriptional activity >30-fold in the presence of 10 nM 17beta-estradiol (E2), but not diethylstilbestrol. The significance of this newly described E2-induced AR transcriptional activity in DU145 human prostate cancer cells was further strengthened by finding patients with Reifenstein partial-androgen-insensitive syndrome that fail in the E2-AR-ARA70 pathway. Together, our data suggest, for the first time, testosterone/dihydrotestosterone may not be the only ligands for the AR. E2 represents another important natural ligand for AR that may play an essential role for the AR function and the development of the male reproductive system.

Amino Acid Sequence↗
PubMed1998

Two distinct kinds of tubular organelles involved in the rapid recycling and slow processing of endocytosed transferrin.

The tubular structures of endosomes are thought to mediate the sorting and recycling of endocytosed macromolecules. These structures have been reported to show considerable morphological variety. However, it is not clear whether they are functionally identical. To address this question, we applied quantitative imaging analysis to characterize tubular organelles loaded with a recycling protein marker, fluorescent transferrin, in living human carcinoma HEp2 cells, using laser scanning confocal microscopy. High-resolution images of the cells demonstrated two types of tubular structures with a distinct morphology and showing a time dependency in their appearance: the fine tubular element and the extensive tubular element. Fine tubular elements 2-10 microns long were distributed throughout the cytoplasm after 10 min of loading with the tracer. Extensive tubular elements 5-20 microns long radiated from the cytocenter after 2 h of loading, but not after 10 min. Time-lapse imaging analysis demonstrated that the half-life of transferrin in the fine and extensive tubular elements was 12 min and approximately 50 min, respectively, at 33 degrees C. Double labeling experiments using fluorescent transferrin and epidermal growth factor indicated that the extensive tubular element was neither a late endosome nor a lysosome. From these results, we conclude that the fine tubular and extensive tubular elements are distinct organelles: the former comprising the sorting endosome and recycling compartment which mediate the rapid recycling of transferrin, and the latter being part of a novel pathway of slower transferrin processing.

Biological Transport↗
PubMed1998

Correlation of plasma protein separation patterns obtained by two-dimensional polyacrylamide gel electrophoresis and by capillary electrophoresis.

We used three different electrophoretic techniques for the analysis of human plasma proteins: (i) two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), with sodium dodecyl sulfate (SDS) used only in slab gel electrophoresis; (ii) capillary isoelectric focusing (CIEF) with no denaturants; (iii) linear polyacrylamide (LPA)-filled capillary electrophoresis with SDS (SDS-CE). With technique (i), data on isoelectric point and molecular size of plasma proteins can be obtained. Techniques (ii) and (iii) are suited to obtain quantitative information on proteins. The separation principle used in technique (ii) is closely related to that used in the first dimension of technique (i), and that used in technique (iii) related to that in the second dimension of technique (i). Therefore, we could successfully correlate protein separation patterns obtained by 2-D PAGE and those obtained by capillary electrophoresis. The advantages of correlating data obtained by various electrophoretic techniques in the course of constructing a comprehensive database on human plasma proteins are discussed.

Blood Proteins↗
PubMed1998

Entry and intracellular localization of Legionella dumoffii in Vero cells.

Organisms of some Legionella species are known to internalize and multiply within epithelial cell lines. During the study on interaction between Legionella spp. and Vero cells, we found that L. dumoffii Tex-KL (ATCC 33343) can enter into Vero cells approximately four to 20 times more often than five other strains of four species of legionella. The mode of entry between L. dumoffii Tex-KL and L. pneumophila Philadelphia-1 was compared and studied by treating Vero cells with reagents which inhibit phagocytosis and endocytosis. Monodansylcadaverine, cytochalasin D and nocodazol were used as inhibitors of receptor-mediated endocytosis, microfilament-dependent phagocytosis and polymerization of microtubules, respectively. The uptake of L. dumoffii Tex-KL required receptor-mediated endocytosis by Vero cells, while the uptake of L. pneumophila Philadelphia-1 used mainly microfilament-dependent phagocytosis. Polymerization of microtubules was necessary for Vero cells for the uptake of both strains of legionella. An electron microscopic examination revealed that some organisms of the L. dumoffii strain Tex-KL escaped from endosomal vacuoles into cytoplasm in the early stage of infection, and proliferated in the cytoplasm. At that period, most of the bacteria were surrounded by rough endoplasmic reticula. In contrast, L. pneumophila Philadelphia-1 proliferated only within ribosome-lined endosome. We suggest that L. dumoffii Tex-KL internalize and proliferate in Vero cells in a different way to L. pneumophila Philadelphia-1, and that there is a variety of the mode of interaction between Legionella spp. and epithelial cells.

Actin Cytoskeleton↗
PubMed1998

[Some techniques for the correction of the congenital heart disease with autologous flap].

14 living flaps in 8 children were used to repair for the congenital heart disease, because artificial material and xeno grafts were shrunk in growing children but living flaps were going to glow with children. It were possible to use the living flaps to reconstruct of pulmonary outflow in truncus arteriosus, for septoplasty in partial anomarous of pulmonary venous return and reconstruction of unloofed coronary sinus in endocardial defect with triatriatum and intraatrial tunnel in TCPC or Fontan type operation.

Cardiac Surgical Procedures↗
PubMed1998

[Clinical advantages and myocardial protection of normothermal CPB--comparison with hypothermal CPB].

We studied the clinical advantages and myocardial protection of normothermal CPB with comparing to hypothermal CPB. 22-cases of adult CABG were classified under two groups, according to the temperature of CPB. (Normothermal group: 37 degrees C, Hypothermal group: 32 degrees C) In both groups, the assistant CPB time after aortic declamp, the use of cardioversion that meaned the spontaneous recovery to sinus rhythm appeared or not, the dose of cathecholamines in- and post-operation, and the amounts of postoperative bleeding (after 6 h and 12 h) were compared as the clinical results and the data of CPK-MB, Myocin LC-II, and Troponin-T were measured as the effects of myocardial protection. The method of myocardial protection was the intermittent antegrade cold blood cardioplegia with terminal warm blood for all cases. As a result, the assistant CPB time after aortic declamp, the use of cardiovasion, and the amounts of postoperative bleeding (both of 6 h and 12 h) were less in normothermal group rather than in hypothermal group. (p < 0.05). However we had no differences about the dose of cathecholamines in post-operation and the data of three items between two groups. So, it suggests that the sufficient effects of myocardial protection could be obtained in normothermal CPB as in hypothermal CPB. Therefore we conclude that normothermal CPB could provide some clinical advantages, such as shortening CPB time, recovery of sinus rhythm, and prevention of postoperative bleeding, compared to hypothermal CPB and sufficient myocardial protection.

Blood Loss, Surgical↗
PubMed1998

Structure of the erythrocyte membrane skeleton as observed by atomic force microscopy.

The structure of the membrane skeleton on the cytoplasmic surface of the erythrocyte plasma membrane was observed in dried human erythrocyte ghosts by atomic force microscopy (AFM), taking advantage of its high sensitivity to small height variations in surfaces. The majority of the membrane skeleton can be imaged, even on the extracellular surface of the membrane. Various fixation and drying methods were examined for preparation of ghost membrane samples for AFM observation, and it was found that freeze-drying (freezing by rapid immersion in a cryogen) of unfixed specimens was a fast and simple way to obtain consistently good results for observation without removing the membrane or extending the membrane skeleton. Observation of the membrane skeleton at the external surface of the cell was possible mainly because the bilayer portion of the membrane sank into the cell during the drying process. The average mesh size of the spectrin network observed at the extracellular and cytoplasmic surfaces of the plasma membrane was 4800 and 3000 nm2, respectively, which indicates that spectrin forms a three-dimensionally folded meshwork, and that 80% of spectrin can be observed at the extracellular surface of the plasma membrane.

Cell Fractionation↗