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Biomedical subjects

F Miura

Publications and source records attributed to F Miura.

At least 19 recordsLinked to original sources
PubMed1996

Impaired fibrinolysis early after percutaneous transluminal coronary angioplasty is associated with restenosis.

This study examined the role of fibrinolytic components in the process of restenosis after percutaneous transluminal coronary angioplasty (PTCA). Seventy-two patients with single-vessel disease who underwent successful PTCA were prospectively selected. Tissue plasminogen activator (TPA), free plasminogen activator inhibitor-1 (free PAI-1), TPA/PAI-1 complex, and total PAI-1 antigen levels were measured before, at 1 week after, and at 3 months after PTCA. Six months after PTCA, the study patients were divided into two groups: 41 patients without restenosis and 31 patients with restenosis. There were no significant differences with regard to sex, age, coronary risk factors, or morphologic changes in the target lesions between the two groups. There were no significant differences in plasma TPA, TPA/PAI-1 complex, or total PAI-1 levels at each sampling period, or in the time courses between the two groups, except for total PAI-1 levels at 1 week after PTCA. Although no significant differences in free PAI-1 levels before PTCA were observed, free PAI-1 levels after PTCA in the patients with restenosis were significantly higher than those in the patients without restenosis. In addition, each group had a significant change in the time course of free PAI-1 levels. The results suggest that impaired fibrinolysis early after PTCA might affect the repair process of vascular injury, which leads to restenosis, and also that serial determination of free PAI-1 levels could help predict restenosis.

Angioplasty, Balloon, Coronary↗
PubMed1996

Characteristics of vasospastic angina with exercised-induced ischemia--analysis of parameters of hemostasis and fibrinolysis.

To characterize the vasospastic angina patients with exercise-induced ischemia, we measured hemostasis (platelet factor 4; PF4, fibrinopeptide A; FPA) and fibrinolytic parameters (tissue plasminogen activator antigen; t-PA, free plasminogen activator inhibitor-1 antigen; free PAI-1) in 15 normal subjects and 33 vasospastic angina patients without significant coronary artery stenosis (less than 50% stenosis). All of the vasospastic angina patients began to feel chest pain within 3 months before diagnostic coronary angiography. Blood samples were obtained from all of the study patients at 8:30-9:30 am before exercise 201Tl emission computed tomography. Vasospastic angina patients were divided into 2 groups; 15 patients with exercise-induced ischemia (group 1) and 18 patients without exercise-induced ischemia (group 2). On coronary angiography, the severity of coronary artery stenosis at the site of spasm in group 1 (34 +/- 5%) was greater than that in group 2 (18 +/- 3%). Plasma FPA and PF 4 levels in group 1 were also significantly higher than those in normal subjects and group 2. Plasma t-PA and free PAI-1 levels in group 1 were significantly higher than those in normal subjects and group 2. Plasma levels of free PAI-1 group 2 were also significantly higher than those in normal subjects. The present study demonstrated that all of the patients with vasospastic angina had impaired fibrinolysis, and these patients with exercise-induced ischemia showed enhanced platelet activation, an enhanced coagulation system, and advanced atherosclerotic lesions. These results suggest that vasospastic angina with exercise-induced ischemia puts patients at increased risk for thrombus formation.

Adult↗
PubMed1993

Reflections on my involvement in orthodontic research.

Some years ago, Professor Takihashi, who was then the greatest living professor of orthodontics in Japan, called on us in Ann Arbor just before his retirement. I asked Dr. Takihashi who would replace him? and he replied, "There's a young man who will do better than I because he will be able to take Japanese orthodontics to the world and bring the world's orthodontics to Japan." That young man was Fujio Miura. Fujio Miura has, in the years since Takihashi spoke to me, written one of the most amazing records in the history of our specialty. His research is as far ranging as anyone's. For example, in biology he has written well on the ethnology of Japanese craniofacial morphology and that of the aborigines in Japan. He has written on developmental biology and on the tissue reaction of tooth movements. In metallurgy he has contrived alloys that have revolutionized our appliances, for he was a pioneer in the use of nickel-titanium wires. Fujio Miura invented direct bonding. Professor Miura has fulfilled Professor Takihashi's predictions well for he has become the most famous orthodontic professor in Japan's history. It is interesting to see that his students occupy most of the chairs of orthodontics in Japan and many elsewhere. Miura is an accomplished artist who has exhibited his work. This personable scholar probably attends more meetings of the American Association of Orthodontists Society than most American members, and he is equally at home in the European society, and many other orthodontic groups in the world.

Dental Alloys↗
PubMed1992

[Responses of antidiuretic hormone (ADH) and atrial natriuretic polypeptide (ANP) to hypertonic saline infusion in essential hypertensive patients and normotensive subjects].

The demonstration that exogenous atrial natriuretic polypeptide (ANP) has markedly lowered plasma antidiuretic hormone (ADH) suggests a possible negative control of endogenous ANP on the secretion of ADH from the posterior hypophysis. To test this possibility and to clarify the role of ADH and ANP in the pathophysiology of essential hypertension (EHT), the responses of ADH and ANP to a hypertonic saline infusion were investigated in EHT patients and normotensive subjects (NT). Twenty inpatients with EHT (10 males and 10 females; 50.5 +/- 6.5y) and 10 NT subjects (5 males and 5 females; 50.6 +/- 7.8y) underwent a 20 min intravenous infusion of hypertonic saline (2.5% NaCl; 0.25ml/kg/min) in a fasting state. Blood samples were drawn before and 10, 20, 30, 45 and 60 min after the infusion and analyzed for ADH and ANP as well as plasma osmolarity (Posm), Na and albumin. Basal levels of ADH and ANP were not significantly different between NT and EHT. ADH was rapidly increased by the infusion in both groups; however, its percent increase was much higher in EHT than in NT during and after the infusion. Surprisingly, a highly significant negative correlation between ADH and ANP was found before and after the infusion in both groups. Although blood pressure was not changed significantly, the enhanced response of ADH to a sodium and volume load may play a role in part in the pathophysiology of EHT. In addition, it has been suggested that a possible suppression by ANP on the secretion of ADH may be one of the mechanisms of the diuretic action of ANP.

Adult↗
PubMed1992

Effect of 4-MET on bond strength and penetration of monomers into enamel.

The effect of 4-[2-(methacryloyloxy)ethoxycarbonyl]phthalic acid (4-MET) in self-curing acrylic resin initiated by BPO-amine on the bond strength to etched enamel was studied. Scanning electron microscopic (SEM) observations of resin-enamel interfaces were carried out to elucidate the bonding mechanism and the effect of 4-MET on the adhesion. 4-MET, which has both hydrophilic and hydrophobic groups, increased the bond strength of self-curing acrylic resin to etched enamel and improved the bonding stability. SEM pictures strongly suggested that 4-MET promoted interpenetration of monomers into enamel prism peripheries and their polymerization therein resulted in excellent adhesion to etched enamel.

Acid Etching, Dental↗
PubMed1992

Changes in the microvasculature after mechanical pressure on the hamster cheek pouch.

The reaction of the microvasculature in the periodontal ligament to mechanical pressure is considered a very important phenomenon with respect to the biological background to orthodontic tooth movement. For clarification of the microvascular reaction to mechanical pressure, an experimental model that incorporated a hamster cheek pouch was established. This in vivo model solves some of the problems of other experimental models of the microvasculature of the periodontal ligament. Blood plasma permeation in this model was examined by means of a blue dye (pontamine sky blue), and histological observation was performed by light and transmission electron microscopy. Increased vascular permeability was observed within 30 min after removal of the mechanical stimulation. The threshold weight resulting in dye leakage was between 1 and 5 g applied for 60 min. From the histological observations, some large gaps between the endothelial cells in venules were found, while most basement membranes remained undisturbed. These observations suggest that the plasma leakage was due to mild traumatic injury to the endothelial cells. Both leukocytes and platelets were observed in the gaps between the endothelial cells in the venule. These types of microvascular reactions to mechanical pressure could initiate tissue changes in the periodontal ligament during orthodontic tooth movement.

Animals↗
PubMed1992

Super-elasticity and thermal behavior of Ni-Ti alloy orthodontic arch wires.

Bending properties and thermal behavior of twenty commercial Ni-Ti alloy orthodontic arch wires were investigated quantitatively to characterize their suitability for clinical use. There was substantial difference among the load-deflection curves obtained by a three-point bending test. Some wires exhibited super-elasticity; load decreased little with decreasing deflection. Others showed good spring-back properties only; load was nearly proportional to deflection. Thermal behavior due to phase transformation of the alloy was examined by differential scanning calorimetry (DSC). Some of the wires did not have the correct transformation temperatures to exhibit super-elasticity at body temperature. Moreover, thermal behavior was closely related to super-elasticity. There were clear thermal peaks in the DSC curves of the super-elastic wires. However, wires without super-elasticity had no peak in the DSC curves.

Dental Alloys↗
PubMed1992

[A dental anthropological study of Chinese in Taiwan (3). Dental trait].

Models of the upper and lower dental arches of 125 Chinese children in Taiwan with acceptable normal permanent dentition were surveyed in order to understand the developmental grades of dental traits from the viewpoint of dental anthropology. Developmental grades of dental traits were classified, calculated, statistically analysed by x2 test and results were summarized. Upper anterior teeth showed high frequency of shovel form; upper lateral incisors showed less tendency of regression. Interstitial cusp, lingual cusp, paracusp, central prominence and occlusal groove of lower premolars developed prominently. Upper molars showed low frequency of Carabelli cusps. Hypocone of upper second molars showed strong tendency of regression, but metacone had low regression tendency and a strong degree of compression. Compared to Japanese, Central American and South American Indians and Caucasians, the development of dental traits of Chinese in Taiwan was more similar to that of Japanese than to others. The characteristics of dental trait of Chinese in Taiwan and Japanese also showed greater similarity to Central and South American Indians than to Caucasians.

Anthropology, Physical↗
PubMed1991

A possible contribution of endogenous atrial natriuretic peptide to proteinuria in patients with chronic renal failure.

Plasma levels of immunoreactive atrial natriuretic peptide (IR-ANP) were measured with a specific radioimmunoassay in 19 undialysed patients with chronic renal failure. At the beginning, an extremely high level of plasma hANP (50 fmol/ml) seen in a patient was rejected with Smirnov's test and was excluded from further statistics. The plasma IR-ANP levels in these patients were significantly higher than those of 19 normal subjects matched with age and sex (10.9 +/- 1.6 vs 5.3 +/- 0.6 fmol/ml, mean +/- SEM, p less than 0.01), and positively correlated with mean blood pressure (r = 0.44, p less than 0.05) and the cardiothoracic ratio (r = 0.65, p less than 0.01), but did not correlate with creatinine clearance (r = -0.38, n.s.). Further, a significant correlation was observed between plasma IR-ANP and urinary protein output (r = 0.47, p less than 0.05). On the other hand, urinary protein output did not correlate significantly with variables such as mean blood pressure, the cardiothoracic ratio or creatinine clearance. Since it has been suggested that ANP enhances glomerular capillary permeability, increased ANP responding to volume overload in those patients may play an important role in increasing urinary protein excretion.

Adult↗
PubMed1991

[Genetic and environmental characteristics in dento-craniofacial morphology--using materials from survey on Latin American Indians].

Most previous researches of hereditary characteristics of the craniofacial skeleton have used the twin-study method. In this study, dental anthropological materials were used to clarify genetic and environmental characteristics of the dento-craniofacial morphology. The sample consisted of four groups including Mexican Indians (N = 71), Peruvian Indians (N = 41) and their ancient ancestors: skulls of Mexican Indians (N = 33) and Peruvian Indians (N = 34). These groups shared the common origin of the Mongoloid race. Morphological similarity and difference among these groups were examined by principal component analysis and Student t-test using the dento-craniofacial data based on roentgenographic cephalograms and dental casts. The morphological similarity means the genetic characteristics which maintained during time differences between ancient and present times and throughout regional differences between Mexico and Peru. The morphological difference means the environmental characteristics which produced during the time differences and throughout the regional differences. Results were as follows: (1) The genetic morphological characteristics were found predominantly in the anterior cranial base, the dental arch form and to a certain extent in the basal portion of the mandible and the vertical dimension of the naso-maxillary complex. (2) The environmental characteristics were found predominantly in the muscular portion of the mandible, the alveolar portions of the maxilla and the mandible, the length of the dental arch and to a certain extent in the antero-posterior dimension of the maxilla.

Adult↗
PubMed1991

[Dental anthropological study of Mongoloid in China].

The purpose of this study was to evaluate the craniofacial and occlusal characteristics of the inhabitants in China. The material consisted of cephalograms, pantomograms, dental casts and anthropological measurements taken from 517 inhabitants: 416 Han Chinese in Beijing, Shanghai, Guangzhou and Changchun and 101 Mongolians in Hohhot. The data were compared among the above five regions and also with the Japanese data. The findings were summarized as follows: I. Craniofacial characteristics; a) The Han Chinese and the Mongolians showed brachycephaly. b) The inhabitants in Guangzhou showed a tendency of bimaxillary protrusion with a smaller facial height, and the inhabitants in Changchun showed a larger gonial angle with a larger facial height than those of the other regions. c) The Mongolians had a larger value of the saddle angle and of the bi-gonial breadth. d) Compared with the Japanese, their craniofacial complex was characterized by a larger facial angle, smaller mandibular plane angle and a smaller gonial angle. II. Occlusal characteristics; a) The inhabitants in China had a similar tendency in the dental arch form and in the dental trait frequency. b) The inhabitants in Beijing had a larger mesiodistal crown-diameter of the anterior teeth than those in the other regions. c) Compared with the Japanese, their teeth were characterized by a smaller mesiodistal crown-diameter (especially on the upper first molar), higher frequency of shovel-shape and lower frequency of Carabelli's tuberculum.

Adolescent↗
PubMed1991

[Acoustical analysis of occlusal sound--transfer functions of oral cavities and characteristics of waveform of occlusal sound].

The purpose of this study is to clarify the acoustical characteristics of the occlusal sound. An FFT analyzer was used to analyze the transfer functions of the oral cavities. The characteristics of the waveform of the occlusal sound were investigated by the time-frequency analysis. The results obtained were as follows: (1) There were three peaks in the low frequency area of the transfer functions of the oral cavities. The duration of the impulse responses of the oral cavities had a wide variation among the individuals. (2) The waveform of the occlusal sound by air-conduction was proved to consist of two components. One was the teeth collision sound produced by the collision of the teeth in the oral cavity and emitted directly out from the oral cavity. The other was the reverberation considered to be formed mainly by the resonance system in the oral cavity. (3) By the time-frequency analysis, the teeth collision sound could be distinguished clearly from the reverberation; the former was recognized as the component where the energy existed up to the high frequency area, while the latter was recognized as the component where the energy existed only in the low frequency area. (4) It was suggested that the teeth collision sound, after separating from the reverberation, should be analyzed for the purpose of obtaining further information about the functional condition of the occlusion from the occlusal sound.

Adult↗
PubMed1991

[A dental anthropological study of Chinese in Taiwan. I). Craniofacial morphology].

The cephalometric films were collected from 30 boys and 30 girls of 12 years of age, and from 36 males and 34 females of 18 years of age; all of whom were Chinese in Taiwan, all possessed acceptable occlusion to survey the craniofacial morphology and characteristics associated with dental anthropology. Data were analysed by the computer program at the Department of Orthodontics of Japan Tokyo Medical and Dental University. Data were compared with Japanese, North American Caucasians, Central and South American Indians from papers. It was concluded that: 1) Chinese in Taiwan were similar to Japanese, Central and South American Indians, in that; all possessed a shorter frontal cranial base and depth of face, and were completely different from North American Caucasians. The direction of growth showed counter-clockwise rotation in the four Mongoloid races; however, Caucasians showed straight--down growth. The four Mongoloid races had more frontal position of A,B point and more labial inclination of anterior tooth axis than Caucasians. 2) Chinese in Taiwan were similar to Japanese, but were different from Central and South American Indians, in having a flatter infraorbital outline, longer facial height, flattened mandibular plane angle and a more frontal position of chin. 3) Chinese in Taiwan were characteristically different from Japanese by having a smaller interincisal angle, lower frontal facial height, mandibular angle and mandibular plane angle. In summary, the results indicated that Chinese in Taiwan are characterized by having a wide but short face pattern, a retroposition of the mandible ramus, a more upright mandible angle and a prominent labial inclination of anterior tooth axis.

Adolescent↗
PubMed1991

[A dental anthropological study of Chinese in Taiwan (2). Teeth size, dental arch dimensions and forms].

Both upper and lower dental study models were collected from 30 boys (12 years old) and 30 girls (12 years old) with acceptable normal occlusion to understand the characteristics of the crown size, dental arch width and length such as (1) mesiodistal diameters of crown size from central incisor to first molar, (2) the width and length of dental arch and basal arch and (3) the morphology of dental arch form. After statistical analysis, data were compared with Japanese, Central and South American Indians and North American Caucasians from papers. The results were: (1) There was no statistical difference in teeth size between males and females, except the upper first molar of males was larger than that of females, lower central incisor of males was smaller than that of females. (2) The dimensions of dental arch of males were larger than that of females in general, especially such items as width and length of basal arch. (3) The crown size of Chinese male was in generally smaller than that of four other races, especially the upper canine, lower central incisor and first molar. The crown size of Chinese females showed that although the lower first molar was smaller than that of Central and South American Indians, but the upper first premolar, lower canine and central incisor were larger than that of Japanese. Upper lateral incisor was larger than that of South American Indians. Compared to that of North American Caucasians, Chinese females had a smaller upper central incisor and a larger upper first premolar. (4) The dimensions of dental arch in Chinese were very similar to Japanese, South and Central American Indians, but wider and shorter than Central and South American Indians. (5) The superimposition of dental arch form showed that the four races of Mongoloids had similar ovoid dental arch forms.

Asian People↗