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Biomedical subjects

N Miyagi

Publications and source records attributed to N Miyagi.

At least 19 recordsLinked to original sources
PubMed2006

[Emergent coronary artery bypass grafting for a patient with cardiopulmonary arrest].

A 59-year-old man was admitted to our hospital due to sudden onset of unconsciousness caused by myocardial infarction with ventricular fibrillation. Emergent coronary angiography under intraaortic balloon pumping revealed 90% stenosis of the left main trunk and left anterior descending artery (LAD), and complete obstruction of the left circumflex artery (Cx) and right coronary artery (RCA). Emergent coronary artery bypass grafting (CABG) to LAD, Cx, and RCA was performed. During the postoperative course, the patient developed ventricular tachycardia/fibrillation. After implantation of an implantable cardioverter defibrillator (ICD), he was discharged on the postoperative day 36. The patient has now resumed normal daily life.

Coronary Artery Bypass↗
PubMed2001

Rapid normalization of marked dilatation of the cerebral duro-venous system in a newborn infant mimicking a great vein of Galen varix.

A newborn infant with a marked dilatation of the cerebral duro-venous system is presented. The patient was diagnosed as having a vein of Galen aneurysmal varix by a cranial ultrasound examination immediately following delivery. Computed tomographic angiography on the following day, however, showed a marked dilatation of the cerebral duro-venous system, including the great vein of Galen, superior sagittal sinus, torcular herophili and transverse sinuses. There were no arteriovenous fistulas at the vein of Galen. Dilatation of the duro-venous system and concomitant heart failure subsided rapidly after intravenous administration of indomethacin for the treatment of the patent ductus arteriosus on the fourth day of life. Dilatation of the duro-venous system in a newborn infant should be differentiated from any form of vein of Galen aneurysm.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

Effects of PEMF on a murine osteosarcoma cell line: drug-resistant (P-glycoprotein-positive) and non-resistant cells.

After pulsed exposure of Dunn osteosarcoma cells (nonresistant cells) to Adriamycin (ADR) at increasing concentrations and single-cell cloning of surviving cells, ADR-resistant cells were obtained. These resistant cells expressed P-glycoprotein and had resistance more than 10 times that of their nonresistant parent cells. Compared to the nonresistant cells not exposed to pulsing electromagnetic fields (PEMF) in ADR-free medium, their growth rates at ADR concentrations of 0.01 and 0.02 micrograms/ml, which were below IC50, were 83.0% and 61.8%, respectively. On the other hand, in the nonresistant cells exposed to PEMF (repetition frequency, 10 Hz; rise time, 25 microsec, peak magnetic field intensity, 0.4-0.8 mT), the growth rate was 111.9% in ADR-free medium, 95.5% at an ADR concentration of 0.01 micrograms/ml, and 92.2% at an ADR concentration of 0.02 micrograms/ml. This promotion of growth by PEMF is considered to be a result of mobilization of cells in the non-proliferative period of the cell cycle due to exposure to PEMF. However, at ADR concentrations above the IC50, the growth rate tended to decrease in the cells not exposed to PEMF. This may be caused by an increase in cells sensitive to ADR resulting from mobilization of cells in the non-proliferative period to the cell cycle. The growth rate in the resistant cells exposed to PEMF was significantly lower than that in the non-exposed resistant cells at all ADR concentrations, including ADR-free culture (P</=0.0114). Therefore, this study suggests that PEMF promotes the growth of undifferentiated cells but progressively suppresses the growth of more differentiated cells, i.e., PEMF controls cell growth depending on the degree of cell differentiation. This study also shows the potentiality of PEMF as an adjunctive treatment method for malignant tumors.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

Popliteal amyloidoma presenting with leg ischemia in a chronic dialysis patient.

The authors report a case of bilateral popliteal amyloidoma causing stenosis of the popliteal artery and vein. This patient had been treated with hemodialysis for 26 years. The diagnosis was made with MR angiography. A popliteal tumor of the right knee was resected surgically and the histologic examination showed deposition of amyloid. After resecting the popliteal tumor, the severe leg pain and intermittent claudication improved. This report suggests that popliteal amyloid tumors should be considered in a patient undergoing long-term hemodialysis who complains of leg pain and intermittent claudication.

Adult↗
PubMed2000

Cerebral hemodynamics after exogenous surfactant administration for respiratory distress syndrome in piglet model.

OBJECTIVE: The rapid improvement of lung function after exogenous surfactant treatment for respiratory distress syndrome (RDS) can affect the functions of several other systems, which includes cerebral blood flow volume (CBF). To evaluate the change in CBF after treatment with exogenous surfactant, we measured CBF in a newborn piglet model with RDS. METHOD: After the lung lavage with normal saline, ten animals under mechanical ventilation were administered either 120 mg/kg surfactant-TA (Surfacten) or air placebo. Heart rate, blood pressure, dynamic lung compliance (Cdyn), PaO2, PaCO2, and CBF were recorded before and every 15 min after surfactant treatment up to 120 min. RESULTS: Cdyn was improved significantly at 45 min and later after treatment; that of the control group remained unchanged. PaO2 increased and PaCO2 decreased significantly after surfactant treatment in both groups. However, the improvement was significantly less in the control group. CBF significantly decreased by about 30% in the control group, and by about 50% in the treated group at 120 min, with a significant difference between groups. Almost 70% of the changes in CBF were attributable to changes in PaCO2 by multivariate regression analysis. CONCLUSIONS: Treatment with exogenous surfactant improves lung compliance, and has little effect on CBF itself. The drop in levels of PaCO2 after treatment, however, had a strong relationship with decreases in CBF.

Animals↗
PubMed2000

Coordinate regulation of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 expression in human vascular smooth muscle cells.

The expression of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) by human vascular smooth muscle cells (SMC) was monitored as a function of the phenotypic modulation in vitro. Cell phenotype was manipulated by varying serum concentration and cell density. Synthetic phenotype was characterized by a minimum expression of the contractile proteins and a maximal proliferation rate. Contractile phenotype was quiescent and expressed a maximal level of contractile proteins. Synthetic cells expressed the highest levels of both MMP-1 and TIMP-1 and displayed maximal collagenolytic activity. No significant change was detected in MMP-2 expression or catalytic activity. Enzyme immunoassays revealed that MMP-1 expression fell by 77+/-2.4-95+/-0.5%, and that of TIMP-1 by 34+/-0.5-59+/-1.9%, as the cells acquired a contractile phenotype. The level of the MMP-1/TIMP-1 complex was similarly reduced by 78+/-2.9-85+/-1.6%. These data demonstrate that the expression of MMP-1 and TIMP-1 are coordinately regulated with SMC phenotype.

Adult↗
PubMed2000

[Effectiveness of carboplatin and etoposide selective intra-arterial chemotherapy for progressive soft-tissue sarcoma].

Four patients with advanced soft tissue sarcomas were treated by selective intra-arterial injection of carboplatin (450 mg/m2/2 hr) and etoposide (200 mg/m2/2 hr). After 2-4 courses of treatment, tumor size was remarkably reduced. Three of the 4 patients became candidates for limb-salvage surgery with a safety margin. During the treatment, patients showed no significant complications except for slight nausea and myelosuppression. This protocol might be a recommendable treatment for advanced soft tissue sarcomas.

Adult↗
PubMed1999

Overexpression of p21Waf-1 in vascular smooth muscle cells: regulation of proliferation, differentiation, and cell size.

Cyclin-dependent kinase inhibitor p21Waf-1 is recognized as a negative regulator of cell cycle progression, and it possibly mediates cell differentiation and apoptosis. To understand the role of p21Waf-1 in phenotypic modulation of vascular smooth muscle cells (SMC), we induced the overexpression of p21Waf-1 in cultured rat SMC. The recombinant adenovirus vector encoding p21Waf-1 (AdvCMVp21) was constructed by homologous recombination and the vector encoding beta-galactosidase (AdvCMVLacZ) was used as an experimental control. Administration of AdvCMVp21 suppressed serum-induced proliferation and cell cycle progression; however, the number of quiescent cells and the population of TUNEL-positive cells were not altered. Overexpression of p21Waf-1 did not affect the expression of contractile proteins and the availability of an endogenous growth factor signal p21Waf-1 may regulate cell cycle progression in SMC without affecting the apoptotic process and cell differentiation. Furthermore, the longitudinal diameter of AdvCMVp21 infected cells was increased compared with that of AdvCMVLacZ infected cells. Total protein content was also increased in AdvCMVp21 infected cells. Responses to the serum stimulation, proliferation and total protein synthesis may be independently regulated. Thus, the suppression of cell cycle progression by p21Waf-1 resulted in cellular hypertrophy of SMC.

Adenoviridae↗
PubMed1999

Cerebral blood flow during treatment for pulmonary hypertension.

AIM: To determine if the haemodynamics of systemic and cerebral circulation are changed during treatment for persistent pulmonary hypertension of the newborn (PPHN). METHODS: Fifteen term newborn piglets with hypoxia induced pulmonary hypertension were randomly assigned either tolazoline infusion (Tz), hyperventilation alkalosis(HAT), and inhaled nitric oxide (iNO). Mean pulmonary arterial pressure (PAP), mean systemic arterial pressure (SAP), and cerebral blood flow volume (CBF) were measured. RESULTS: During hypoxic breathing, PAP increased significantly in all groups. After treatment PAP decreased significantly in all groups, but no significant difference was observed between groups. SAP decreased significantly only in the Tz group, and CBF reduced significantly only in the HAT group. On the other hand, iNO did not change SAP or CBF. CONCLUSION: Inhaled NO might be ideal for the resolution of pulmonary hypertension.

Alkalosis, Respiratory↗
PubMed1999

Postnatal change of renal artery blood flow velocity and its relationship with urine volume in very low birth weight infants during the first month of life.

Although the renal artery blood flow velocity has been investigated recently using the ultrasound Doppler method, little is known about the longitudinal change of renal artery blood flow velocity and its relationship with urine volume in very low birth weight infant. Thus, we measured renal artery blood flow velocities by means of the pulse Doppler method in 28 very low birth weight infants. Maximum, minimum, and mean blood flow velocities were determined at postnatal days 0, 1, 2, 3, 4, 5, 6, 13, 20, and 27. The resistance index was also calculated. The maximum and mean blood flow velocities increased gradually after birth, and were significantly higher at 13, 20, and 27 days after birth. The minimum blood flow velocity and the resistance index were relatively constant during the study period. The mean blood flow velocities were also analyzed for any correlation with urine volume. There was a poor correlation between urine volume (ml/kg/day) and mean blood flow velocity (cm/s) (Y = 2.38X + 57.4, Y: urine volume, X: mean blood flow velocity, n = 161, r = 0.338, P < 0.01). However, if the mean renal artery blood flow velocity was less than 10 cm/s, oliguria was observed in most cases. The measurement of the renal artery blood flow velocities appears to be useful in understanding the background condition of renal function in very low birth weight infants.

Aging↗
PubMed1999

Transumbilical embolization of a congenital dural arteriovenous fistula at the torcular herophili in a neonate. Case report.

A neonate, in whom a congenital cerebral vascular anomaly had been diagnosed prenatally, exhibited progressive high-output congestive heart failure soon after birth. Cerebral angiography revealed a congenital dural arteriovenous fistula (AVF) with a huge dural lake located at the torcular herophili. In addition to the meningeal blood supply, an unusual pial blood supply from all cerebellar arteries was observed to feed the fistula. The patient was treated by repeated transarterial and transvenous embolization through the umbilical venous route. To the authors' knowledge, neither the existence of a congenital dural AVF at the torcular herophili presenting with an enormous pial blood supply or the technique of trans-umbilical venous intervention has been reported in the literature.

Arteriovenous Fistula↗
PubMed1998

Correlation between bone mineral density and intervertebral disc degeneration.

STUDY DESIGN: Intervertebral disc area, disc bulge ratio, and bone mineral density were measured in 86 postmenopausal women and the data analyzed. OBJECTIVE: To examine quantitatively the correlation between intervertebral disc degeneration and bone mass. SUMMARY OF BACKGROUND DATA: In results of previous studies, an inverse correlation between osteoporosis and spondylosis has been reported. In these studies, only radiographic findings were used to evaluate spondylosis; changes in the intervertebral disc itself were not investigated. METHODS: To determine bone mass, total-body bone mineral density, lumbar bone mineral density, and age-matched control values of bone mineral density were measured by dual-energy X-ray absorptiometry in all cases. To evaluate intervertebral disc degeneration, disc area and disc bulge ratio (calculated by measuring the areas protruding from lines connecting the middle points of the anterior and posterior borders of the vertebral bodies) were obtained from four discs, using magnetic resonance images of the lumbar spine. The correlation between bone mass data and disc area data was analyzed. RESULTS: Bone mineral density showed a significant decrease with increasing age. Disc area and disc bulge ratio had no relation to age. There was a negative correlation between total-body bone mineral density, lumbar bone mineral density, and age-matched control values versus disc area, and a positive correlation between all bone mineral density data and the disc bulge ratio. CONCLUSIONS: According to the results of the analysis by disc morphology and bone mass, especially total body bone mineral density, bone mass has an inverse correlation to intervertebral disc degeneration--i.e., reduction and disc bulge--which is important when considering degenerative spinal diseases and osteoporosis.

Absorptiometry, Photon↗
PubMed1998

Expression of the cyclin-dependent kinase inhibitor, p21Waf-1/Cip-1/Sdi-1, in human vascular smooth muscle cells in the proliferating state.

Excess proliferation of vascular smooth muscle cells (SMC) is an important aspect of atherogenesis. Cell-cycle regulatory proteins such as cyclin and cyclin-dependent kinases are vital for cell-cycle progression. To understand the role of the cyclin-dependent kinase inhibitor, p21Waf-1/Cip-1/Sdi-1 (p21Waf-1), on human atherogenesis, we tested p21Waf-1 expression in human atherosclerotic lesions and cultured SMC. Immunohistochemical staining revealed that SMC in neointimal lesions expressed p21Waf-1. No evidence of the p53 protein could be detected. By Western blotting, cultured SMC obtained from a neonate revealed that a higher level of p21Waf-1 expression correlated with a higher expression of proliferating cell nuclear antigen and a lower expression of the contractile protein than that observed in cells obtained from aged donors. When the phenotypes of SMC were changed by modification of serum concentration and cell densities, p21Waf- expression was maximal in serum-stimulated SMC at low cell densities despite the low expression of p53. Furthermore, serum stimulation transiently increased the p21Waf-1 expression of quiescent SMC, which was synchronized with the transition from the G0/G1 to the S phase as well as with cyclin D1 expression. These results may suggest that the negative regulator of cell-cycle progression also plays a role in regulating the appropriate cell-cycle progression in SMC. Growth stimuli may induce both growth-promoting and growth-inhibitory factors in SMC. The balance between these two opposing factors may play an important role in the determination of cell-cycle progression.

Arteriosclerosis↗
PubMed1998

Fibroblast growth factor-2 and -9 regulate proliferation and production of matrix metalloproteinases in human gliomas.

Fibroblast growth factor (FGF) signaling has been recognized in human gliomas. We tested the effect of FGF-2 and FGF-9 on the proliferation and the expression of matrix metalloproteinases (MMPs) and their inhibitor (TIMP-1) in vitro. Both FGFs showed mitogenic activity on U251MG and NMC-G1 cells. MMP-1 expression and collagenolytic activity of NMC-G1 but not of U251MG, and TIMP-1 expression of both cells were stimulated by FGFs. MMP-2 expression, gelatinolytic activity, and chemoinvasion on the matrigel were not altered. FGFs may regulate proliferation and microenvironmental factors independently in each glioma type.

Brain Neoplasms↗
PubMed1993

Low friction total knee arthroplasty with the alumina ceramic condylar prosthesis.

This paper evaluates the failure and wear properties of the alumina ceramic posterior cruciate condylar total knee prosthesis, and reports the preliminary clinical results of this prosthesis. Thirteen sets of the alumina ceramic prostheses were used for destruction and wear tests. The average ultimate load in the static destruction tests showed 2.63 x 10(4) Newtons in the femoral component, and 1.28 x 10(4) Newtons in the tibial component. The average ultimate energy in the impact destruction tests showed 22.1 Joules in the femoral components, and 20.3 Joules in the tibial components. The wear test demonstrated that the average depth of wear was 0.04 mm in the alumina ceramic prostheses, and 0.20 mm in the Vitallium prostheses. Observation of the UHMWPE wear surface with a scanning electron microscope indicated many deep scratches and a scooped concave lesion in the Vitallium prostheses; there were few deep scratches in the alumina ceramic prostheses. Thirty patients underwent 32 total knee arthroplasties using the alumina ceramic posterior cruciate condylar prosthesis between 1988 and 1990. The results were evaluated as excellent for 59%, good for 28%, fair for 10%, and poor for 3%. Critical roentgenographic review demonstrated no cases of loosening or sinking after arthroplasties using the alumina ceramic prosthesis. Radiolucent lines were observed only in 4 knees (12%) cases. All were observed around the tibial components, but were less than 1 mm in thickness. The frequency of the radiolucent lines is less than that observed in the Vitallium prosthesis at the same followup period. The alumina ceramic posterior cruciate condylar prosthesis may have sufficient durability and excellent wear properties for low friction total knee arthroplasty.

Aluminum Oxide↗
PubMed1990

The Cohen syndrome: does mottled retina separate a Finnish and a Jewish type?

A new familial cases of the Cohen syndrome in two brothers of one-half second-cousin parents is reported. Typical clinical manifestations of the syndrome; i.e., mental deficiency, hypotonia, characteristic facial appearance, long, narrow hands and feet with elongated fingers, and mottled retinae were present in both patients. Both patients also had leukopenia. Clinical manifestations of the Cohen syndrome in patients are highly variable, and mottled retina has been observed in 22 of 87 patients (25%). However, an association of mottled retina in patients with the Cohen syndrome is likely to be related to the families and ethnic groups. Among 19 familial cases, mottled retina was observed in all affected sibs from five families, but in 13 families none of the affected sibs had the mottled retina. All Finnish patients had the mottled retina, but this was noted in only one of 39 Jewish patients. Based on these data, we hypothesize that two alleles at the gene locus for the Cohen syndrome exhibit different clinical manifestations: one is a Finnish type with mottled retina, and the other is a Jewish type without retinal anomalies.

Abnormalities, Multiple↗