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Biomedical subjects

H Miyamoto

Publications and source records attributed to H Miyamoto.

At least 163 records · Page 9Linked to original sources
PubMed1997

Blood flow in the carotid artery during breath-holding in relation to diving bradycardia.

The present study investigated the mechanism of diving bradycardia. A group of 14 healthy untrained male subjects were examined during breath-holding either out of the water (30-33 degrees C), in heat-out immersion, or in whole-body submersion (27-29 degrees C) in a diving pool. Blood velocity, blood volume flow in the carotid artery, diastolic blood pressure and electrocardiogram were measured and recorded during the experiments. The peak blood velocity increased by 13.6% (P < 0.01) and R-wave amplitude increased by 57.1% (P < 0.005) when the subjects entered water from air. End-diastolic blood velocity (Ved) in the carotid artery increased significantly during breath-holding, e.g. Ved increased from 0.20 (SD 0.02) m.s-1 at rest to 0.33 (SD 0.04) m.s-1 (P < 0.001) at 50.0 s in breath-hold submersion to a 2.0-m depth. Blood volume flow in the carotid artery increased by 26.6% (P < 0.05) at 30 s and 36.6% (P < 0.001) at 40 s in breath-hold submersion to a 2.0-m depth. Diastolic blood pressure increased by 15.4% (P < 0.01) at 60 s during breath-holding in head-out immersion. Blood volume flow, Ved and diastolic blood pressure increased significantly more and faster during breath-holding in submersion than out of the water. There was a good negative correlation with the heart rate: the root mean square correlation coefficient r was 0.73 (P < 0.001). It was concluded that an increased accumulation of blood in the aorta and arteries at end-diastole and decreased venous return, caused by an increase in systemic peripheral resistance during breath-holding, underlies diving bradycardia.

Adult↗
PubMed1997

Expression of cytochromes P450aldo and P45011 beta in rat adrenal gland during late gestational and neonatal stages.

The development of the rat adrenal gland during late gestational and neonatal stages was studied by following the expression of aldosterone synthase cytochrome P450 (P450aldo) and glucocorticoid-synthesizing cytochrome P450 (P45011 beta). Cells expressing P450aldo, a functional marker for the mineralocorticoid-synthesizing zona glomerulosa, were not detected until day 20 of fetal age, i.e., 2 days before birth, although the zona glomerulosa cells were histologically recognizable at the 18th day of gestation. The intensity of P450aldo staining thereafter became stronger with age in the outer portion of the cortex. Cells expressing P45011 beta, a marker for the glucocorticoid-producing zona fasciculata, were present in the fetal adrenals on the 18th day. P45011 beta-positive cells were distributed over the whole adrenal gland and intermingled with the cells containing tyrosine hydroxylase, a marker enzyme for medullary cells. The P45011 beta-positive and tyrosine hydroxylase-positive cells began to separate on the 20th day, and were completely resolved from each other around the third day after birth. Expression of P450aldo and P45011 beta, together with that of tyrosine hydroxylase, thus serves as a suitable marker for studying the development of the adrenal gland.

Adrenal Glands↗
PubMed1997

Biodegradable scleral implant for intravitreal controlled release of fluconazole.

PURPOSE: To evaluate the feasibility of using a biodegradable polymeric scleral implant containing fluconazole (FLCZ), a bis-triazole antifungal agent, as a potential intravitreal-controlled drug delivery system. METHODS: The scleral implants, loaded with 10, 20, 30, and 50% FLCZ, were prepared with biodegradable polymers of poly (DL-lactide-co-glycolide). Those with all loading doses were used for the in vitro release studies; those with 30% FLCZ were used for the intravitreal release studies in pigmented rabbits. The in vitro and in vivo release rates of FLCZ from the implants were measured periodically with spectrophotometry and high performance liquid chromatography, respectively. The effects of the implants on ocular tissues were evaluated ophthalmoscopically, histologically, and electrophysiologically. RESULTS: The scleral implants loaded with 10, 20, and 30% doses gradually released FLCZ over 4 weeks in vitro; those with 50% FLCZ released most of the drug in one week. FLCZ concentration in the rabbit vitreous remained within the 99% inhibitory concentration for Candida albicans for 3 weeks after implantation. The scleral implant gradually biodegraded, and it disappeared by 4 months after implantation. The electrophysiologic and histopathologic findings demonstrated no substantial toxic reactions in the ocular tissues. CONCLUSION: The current study suggests that a biodegradable, polymeric scleral implant containing FLCZ may be a promising intravitreal drug delivery system to treat fungal endophthalmitis.

Animals↗
PubMed1997

Molecular determination of infection source of a sporadic Legionella pneumonia case associated with a hot spring bath.

To determine the infection source of a sporadic Legionella pneumonia case associated with a hot spring bath, we used five molecular methods, including repetitive element polymerase chain reaction (rep-PCR), arbitrarily primed PCR (AP-PCR), ribotyping, restriction endonuclease analysis (REA), and macrorestriction endonuclease analysis (MREA) by pulsed-field gel electrophoresis. L. pneumophila serogroup (SG) 3 strain EY 3702, isolated from an intratracheal specimen of a 71-year-old Japanese female who developed pneumonia after nearly drowning in a hot spring spa bath, produced rep-PCR and AP-PCR fingerprints identical to those of L. pneumophila SG 3 strains EY 3768 and EY 3769 isolated from the bath water. Four epidemiologically unrelated L. pneumophila SG 3 strains showed different rep-PCR or AP-PCR fingerprints from those of the three EY strains (EY 3702, 3768, and 3769). The three EY strains were also genotypically indistinguishable by ribotyping with EcoRI and PstI, by REA with EcoRI or HindIII, and by MREA with NotI. Based on these results, we identified the bath water of the hot spring spa as the source of infection of this patient, even though the viable number of the organisms in the bath water was low (3 CFU/100 ml) when determined 27 days after her nearly drowning.

Aged↗
PubMed1997

Outcomes of infants whose mothers are positive for human herpesvirus-6 DNA within the genital tract in early gestation.

It has been reported that HHV-6 (human herpesvirus-6) DNA has been identified within the female genital tract. However, the clinical significance of this finding has been unclear. The clinical outcome of the presence of HHV-6 DNA in the genital tract of pregnant women on their infants was evaluated in the present study. One hundred and ten pregnant women were enrolled. Vaginal swabs were collected between 4 and 8 weeks of gestation and the presence or absence of HHV-6 DNA was evaluated by nested polymerase chain reaction (nPCR). The swabs were cultured to isolate the virus. The women were divided into two groups: HHV-6 DNA-positive, and negative. The outcome variables of the infants of these two groups were statistically estimated at birth and at 1 month of age. Saliva and blood cells were collected from the infants at birth and at 1 month of age and were also evaluated by nPCR. HHV-6 DNA was detected in the vaginal swabs of 28 pregnant women (25.5%), but was not detected in any other samples, including saliva and blood cells from their infants. Virus could not be isolated from any vaginal samples. Any outcome variables were not significantly different between the two groups. The presence of HHV-6 DNA within the genital tract of pregnant women did not affect the health of their infants. It is suggested that HHV-6 transmission to infants through the genital tract of their mothers during pregnancy does not occur, or only very rarely.

Adult↗
PubMed1997

[Serological differences in Helicobacter pylori].

To study antigenic differences in Helicobacter pylori (H. pylori), we performed immunoblot (IB) analysis with monoclonal antibody, MAb102, and measured the serum antibody titer with captured ELISA method with MAb102 antibody. In IB analysis, specific 54 K antigen was detected in 39 strains derived from patients with gastritis, gastric ulcer, duodenal ulcer, and gastric carcinoma. But only one strain (GC32 strain) isolated from a patient with gastric cancer did not react with MAb102 antibody. In the result of antibody titer with captured ELISA method using other six strains of H. pylori as antigen, H. pylori strains were divided into 3 groups, group R (RD26, T7, and T13 strains), group E (England and MR31 strains), group T (T37 strain). However, four cases belonged to false negative in ELISA method. These cases could have been infected with H. pylori strains such as GC32 strain. These strains did not have 54 K antigen nor 54 K related antigen which is different in its antigenicity from the 54 K antigen of the six strains. Thus the GC35 strain and the strain(s), which infected these four cases, consisted of other group, group N. These results suggested that 54 K antigen is usually stable in many strains, but occasionally different in antigenicity in some strains.

Adult↗
PubMed1997

Development of a new seminested PCR method for detection of Legionella species and its application to surveillance of legionellae in hospital cooling tower water.

The presence of PCR inhibitors in water samples is well known and contributes to the fact that a practical PCR assay has not been developed for legionella surveillance. In this study, we devised a new seminested PCR assay for detection of Legionella spp. in water samples as a means of overriding the PCR inhibitors without loss of sensitivity. The seminested PCR assay utilized primers to amplify the 16S rRNA gene (LEG primers) of 39 Legionella spp. The assay was specific to legionellae, and the sensitivity was 1 fg of extracted Legionella DNA in laboratory examination. To evaluate the feasibility and sensitivity of the PCR assay in identifying the presence of legionellae, it was used to survey Legionella contamination in the water of 49 cooling towers of 32 hospitals. A commercially available EnviroAmp Legionella kit and a culture method were also used in the survey for comparison with the seminested PCR assay. The detection rates of legionellae in the samples were 91.8% (45 of 49) by the PCR assay and 79.5% (39 of 49) by the culture method. The EnviroAmp kit revealed that 30.6% of the water samples (15 of 49) contained inhibitors of the PCR amplification. However, the seminested PCR assay could produce the Legionella-specific DNA bands in 14 of the 15 samples. Although 8 of the 14 samples were positive in the first-step PCR, 6 of the 14 samples became positive in the second-step PCR. These results suggest that the effect of PCR inhibitors in samples, if any, can be reduced because of the dilution of the sample in the second-step PCR and that sensitivity of detection can be increased by the second-step PCR. Thus, the seminested PCR assay with LEG primers to amplify the 16S rRNA gene of 39 Legionella spp. was a practical and sensitive method to detect Legionella spp. in water samples.

Air Conditioning↗
PubMed1997

Therapeutic effect of cytomedicine on mesangio-proliferative glomerulonephritis in human interleukin-6 transgenic mice.

We previously demonstrated that IgG1 plasmacytosis in human interleukin-6 transgenic mice (hIL-6 Tgm) was suppressed by the implantation of SK2 hybridoma cells (SK2 cells, which secrete anti-hIL-6 monoclonal antibodies) microencapsulated in a semipermeable and biocompatible device. In this study, we demonstrated that the mesangio-proliferative glomerulonephritis in hIL-6 Tgm was also improved by the same treatment. These results strongly support the concept of cytomedicine, which is a novel drug delivery system (DDS) using living cells. However, an electron microscopy study showed that cytomedicine has a limited duration of effectiveness because of the disappearance of space for cell proliferation in the microcapsule. Thus, the control of cell proliferation in a device must be developed to prolong the function and effectiveness of cytomedicine.

Animals↗
PubMed1997

Monoclonal antibodies against pig ovarian follicular granulosa cells induce apoptotic cell death in cultured granulosa cells.

Two monoclonal antibodies capable of inducing granulosa cell apoptosis were produced against granulosa cells prepared from antral follicles of pig ovaries. The healthy follicles, 4-5 mm in diameter, were dissected from the ovaries of gilts, and then granulosa cells were isolated. BALB/c female mice were immunized with the isolated granulosa cells. Antibodies against the granulosa cells were detected by immunofluorescent staining using frozen ovarian sections. The isolated spleen cells prepared from immunized mice producing antibodies against the granulosa cells were fused with Sp2/O-Ag 14 mouse myeloma cells by standard hybridization techniques. Two hybridoma clones, PFG-1 and PFG-2, which produced specific IgM antibodies against granulosa cells were selected. Western blotting analysis revealed that PFG-1 and PFG-2 antibodies specifically recognized cell-membrane proteins with molecular weights of 55 and 70 kD and isoelectric points of 5.9 and 5.4, respectively. The monoclonal antibodies immunohistochemically reacted with granulosa cells of healthy follicles. When the isolated granulosa cells prepared from healthy follicles were cultured in medium containing 0.1 or 10 micrograms/m/PFG-1 or PFG-2 antibodies, respectively, the cells underwent apoptosis as determined by nuclear morphology, DNA electrophoresis and flow cytometric analysis. In conclusion, these two monoclonal antibodies against granulosa cells have cell-killing activity in cultured granulosa cells.

Animals↗
PubMed1997

Lectin histochemistry in rat liver fibrosis induced by heterologous serum sensitization.

The localization of carbohydrates in rat livers with fibrosis induced by heterologous serum was examined by lectin histochemical and biochemical techniques. Twenty-four lectins were used to visualize the different carbohydrates in paraffin sections of normal and fibrotic liver tissues. No differences in staining patterns of these lectins were observed between normal and fibrotic livers in hepatocyte cell membranes including bile canaliculi, sinusoidal endothelial, or bile ductal cells. Kupffer cells strongly stained with Vicia villosa agglutinin (VVA) were seen only in the periportal zone of the normal liver, but they were observed in the periportal zone and scattered throughout the pseudolobular zone in the fibrotic liver. The cytoplasm of some hepatocytes was strongly stained by Bandeiraea simplicifolia lectin-I (BSL-I). BSL-I positive hepatocytes in normal liver were localized in the periportal zone, but those in the fibrotic liver were scattered in the periportal and perifibrous zones. After polyacrylamide gel electrophoresis of liver glycoproteins, differences in molecular sizes of BSL-I positive glycoproteins (79 and 81 kD) were detected by lectin blotting. Cell density of perifibrous BSL-I positive hepatocytes may be useful as a diagnostic parameter for liver fibrosis and/or cirrhosis. Two distinct staining patterns with twelve lectins were observed in fibrotic septa of the fibrotic liver. The fibrotic septa were stained with six characteristic lectins, and the centrilobular septa were stained with all these twelve of lectins. Histopathological assessment of the centrilobular fibrotic septa stained with these characteristic lectins may contribute to the diagnosis and prognosis of hepatic fibrosis.

Animals↗
PubMed1997

[A surgical case report--rare association of tetralogy of Fallot with cor triatriatum, unroofed coronary sinus and persistent left superior vena cava].

We experienced the rare association of Tetralogy of Fallot with cor triatriatum, unroofed coronary sinus and persistent left superior vena cava. Only one case of this association has ever been reported in the literature. We successfully performed a total correction which consisted of a resection of the intra-left atrial fibrous membrane, reconstruction of the LSVC return pathway to the right atrium with PTFE graft, atrial partition with a bovine pericardial patch and the conotruncal repair for Tetralogy of Fallot. Cardiac catheterization 6 months after operation demonstrated the smooth drainage from LSVC into the right atrium without pressure gradient. His postoperative course has been uneventful.

Cardiac Surgical Procedures↗
PubMed1997

[Investigation into mediastinal lymph node metastasis of lung cancer and rationale for decision of the extent of mediastinal dissection].

UNLABELLED: From the study on the regional lymphatic drainage and investigation into mediastinal lymph node metastasis of lung cancer, we have decided the extent of mediastinal dissection as follows; 1) For right lung cancer, as the routine procedure, extended systematic ipsilateral mediastinal dissection including the left tracheobronchial region, the anterior and the posterior ipsilateral mediastinum through a conventional thoracotomy. 2) For left lung cancer, as the routine procedure, systematic bilateral mediastinal dissection through a median sternotomy. 3) For the patients with advanced lymph node metastasis (the highest mediastinal or the cervical node involvement) or direct extension into the upper mediastinum of cancer in any side of the lungs, the lower half of modified radical neck dissection combined with systematic bilateral mediastinal dissection through a cervical collar incision and median sternotomy. RESULTS: 1. The noteworthy location and incidences of mediastinal lymph node involvement were as follows; 1) Among 34 patients of right lung cancer with pN2-3 M0 disease, in 5 patients the anterior mediastinal node involvement and in 6 patients (18%) the contralateral tracheobronchial node involvement were found by the pathological investigation at surgery. 2) The incidences of contralateral mediastinal node involvement at median sternotomies were 20% of 15 patients of the left upper lobe primary and 57% of 7 patients of the left lower lobe primary. 2. Postoperative survival rates calculated with Kaplan-Meier method; 1) The five-year survival rates were 67% in 22 patients with pT1-2N2M0; 72% in 20 patients with pT1-2N2-3 alpha (one level) M0 and 65% in 13 patients with pT1-2N2-3 alpha (multi level) M0. 2) The five-year survival rate of 8 patients with N3 gamma whose cancer were diagnosed as cN0-3 alpha preoperatively and resected completely was 60%. In conclusion, these results encourage us to continue this study because we can believe that our systematic mediastinal dissection beyond the anatomical difficulties would bring better prognoses in the patients with pN2-3 disease.

Humans↗
PubMed1997

[A case of primary orbital chondrosarcoma].

The case of a twenty-year-old male with orbital chondrosarcoma is reported. He visited National Defense Medical College Hospital because of reduced vision in the right eye since two months previously. His corrected visual acuity was 8/20 in the right eye and 20/20 in the left eye. Fifteen degrees lateral displacement of the right globe and limitation of right ocular movement were recognized. Right fundus examination revealed optic disc edema and protuberant nasal fundus. Orbital computed tomography (CT) demonstrated a high density area between the inner part of the right orbit and the ethmoid sinus. Magnetic resonance imaging (MRI) showed a smoothly outlined and low intensity (T1) space occupying lesion. This lesion was irregularly enhanced by gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA). This orbital tumor was removed by an anterior approach. Histopathological examination revealed well-differentiated chondrosarcoma (grade 1) as determined by small prominent chondromatous cell projection into the collagen fibrous stroma, and existence of binucleate cells in the hypercellular region. After the operation the disc edema disappeared and his corrected right visual acuity improved to 20/20.

Adult↗
PubMed1997

[Successful aortic root replacement with pulmonary autograft (Ross) in two cases of congenital aortic stenosis].

Two cases of 7 and 23 year of age with congenital aortic stenosis associated with the small valve annulus underwent successful aortic root replacement with pulmonary autograft (Ross procedure). Preoperative pressure gradient and the valve size were 120 and 80 mmHg, and 16 and 18 mm, respectively. Even with the small native aortic annulus, pulmonary autografts could be implanted to aortic annulus without autograft distortion by the method of total aortic replacement. The right ventricular outflow reconstruction was performed with PTFE-valved bovine pericardial conduit with securing the posterior muscular edge by a strip of autologous aortic wall. Postoperative course in both patients was uneventful without any rhythm disturbances. During the 12 and 14 months of follow-up, both patients were in excellent clinical condition with no evidence of autograft valve regurgitation and functional deterioration of valved conduit. This procedure was thought to be a preferable method of young cases with congenital aortic stenosis.

Adult↗
PubMed1997

[A mesenchymal malignant mesothelioma that changed from mixed type to purely sarcomatous type].

A 65-year-old man was admitted to the hospital because of an abnormal shadow on a chest roentgenogram. A diagnosis of mixed-type malignant mesothelioma was made after transcutaneous needle biopsy and thoracoscopic biopsy. The tumor was considered to be inoperable because it had diffusely invaded surrounding tissue, and therefore the patient was treated with chemotherapy only. About one year later, he died of acute pneumonia. At autopsy, a mesenchymal malignant mesothelioma that did not have an epithelial component was found. We know of no previous report of a case in which a tumor with a biopsy-proven epithelial component apparently changed to a purely sarcomatous type. No satisfactory explanation for this phenomenon has been offered.

Aged↗