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Biomedical subjects

M Miyao

Publications and source records attributed to M Miyao.

At least 37 records · Page 2Linked to original sources
PubMed2000

Controlled release of vascular endothelial growth factor by use of collagen hydrogels.

In vivo profile of vascular endothelial growth factor (VEGF) release from collagen hydrogels was investigated comparing that of hydrogel degradation while angiogenesis induced by the released VEGF was assessed. Collagen sponges were chemically cross-linked with different amounts of glutaraldehyde for various time periods. When 125I-labeled collagen hydrogels incorporating VEGF were subcutaneously implanted into the back subcutis of mice, the hydrogel radioactivity decreased with time, the decrement profile depending on the cross-linking conditions. The radioactivity was retained for longer time periods as the glutaraldehyde concentration and cross-linking time increased. Implantation study of collagen hydrogels incorporating 125I-labeled VEGF revealed that the remaining VEGF radioactivity decreased with time and the retention period was prolonged with the decreased hydrogel biodegradation. The slower the hydrogel degradation, the longer the period of VEGF retention. The collagen hydrogel incorporating VEGF induced significant angiogenesis around the implanted hydrogel, in marked contrast to VEGF in the solution form and VEGF-free empty hydrogel. The retention period of angiogenesis became longer with a decrease of the in vivo degradation rate of hydrogels. It is possible that the slower degraded hydrogel achieves a longer period of VEGF release, resulting in prolonged angiogenetic effect. We concluded that in our hydrogel system, biologically-active VEGF was released as a result of in vivo degradation of the hydrogel.

Absorbable Implants↗
PubMed1999

Association of bone mineral density with a polymorphism of the peroxisome proliferator-activated receptor gamma gene: PPARgamma expression in osteoblasts.

The peroxisome proliferator-activated receptor gamma (PPARgamma) protein as well as its transcript was detected in primary osteoblasts derived from rat calvariae. To analyze the possible involvement of PPARgamma in the human bone metabolism, association between bone mineral density (BMD) and a polymorphism of PPARgamma gene was investigated in Japanese postmenopausal women. We examined a polymorphism corresponding to a silent C --> T transition located in exon 6 of the PPARgamma gene, that was previously reported to be associated with plasma leptin levels in the obese. The frequencies of the C and T alleles in the population studied here were 0.851 and 0.149, respectively. When we separated the subjects into two groups, one bearing at least one T allele (CT + TT) and the other which did not (CC), the former subjects had lower BMD (Z score of total body; 0.056 +/- 1.00. L2-4; -0.25 +/- 1.26, mean +/- standard deviation). These data suggest that there is an association between the restriction fragment length polymorphism (RFLP) of PPARgamma gene and BMD and the possible involvement of this single nucleotide polymorphism (SNP) in the cause of postmenopausal osteoporosis in Japanese women.

Aged↗
PubMed1999

Restoration of the high-potential form of cytochrome b559 of photosystem II occurs via a two-step mechanism under illumination in the presence of manganese ions

Spinach photosystem II membranes that had been depleted of the Mn cluster contained four forms of cytochrome (Cyt) b559, namely, high-potential (HP), HP', intermediate-potential (IP) and low-potential (LP) forms that exhibited the redox potentials of +400, +310, +170 and +35 mV, respectively, in potentiometric titration. When the membranes were illuminated with flashing light in the presence of 0.1 mM Mn2+, the IP form was converted to the HP' form by two flashes and then the HP' form was converted to the HP form by an additional flash. The quantum efficiency of the first conversion appeared to be quite high since the conversion was almost complete after two flashes. By contrast, the second conversion proceeded with low quantum efficiency and 40 flashes were required for completion. The effects of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) suggested that the first conversion did not require electron transfer from QA to QB while the second conversion had an absolute requirement for it. It was also suggested that the first conversion involved the reduction of the heme of Cyt b559, probably by QA-, and we propose that direct reduction by QA- induces a shift in the redox potential of the heme. The second conversion was also accompanied by the reduction of heme but it appeared that this conversion did not necessarily involve the reduction. The effects of DCMU on the reduction of heme suggested that the heme became reducible by QB- after the first conversion had been completed. This observation implies that the efficiency of electron transfer from QA to QB increased upon the conversion of the IP form to the HP' form, and we propose that restoration of the high-potential forms of Cyt b559 itself acts to make the acceptor side of photosystem II functional.

Journal Article↗
PubMed1999

Association study of parathyroid hormone gene polymorphism and bone mineral density in Japanese postmenopausal women.

Association of BST B1 restriction fragment length polymorphism (RFLP) of the parathyroid hormone (PTH) gene with bone mineral density (BMD) was examined in 383 healthy postmenopausal women in Japan who were unrelated. The RFLP was represented as B or b, the capital letter signifying the presence of and the small letter the absence of restriction site for BST B1. The frequency of each genotype-BB, Bb, and bb-was 82.5%, 16.7%, and 0.8%, respectively. When we statistically compared age, years after menopause, body height, and body weight between the BB genotype and the Bb genotype groups, there was no significant difference between the groups. However, the lumbar BMD and the score of BMD adjusted for age and body weight (Z score) were significantly lower in the group of genotype Bb than in the BB: 0.859 +/- 0.019 g/cm2 versus 0.925 +/- 0. 011 (mean +/- SE, P = 0.01) and -0.412 +/- 0.138 versus 0.067 +/- 0. 082 (mean +/- SE, P = 0.01). In addition, the Z score of total body BMD in the Bb genotype group was lower than that in the BB group. Comparison of serum and urinary biochemical bone metabolic markers suggested that the subjects with Bb genotype might be in a relatively higher state of bone turnover than those with BB genotype. These results suggest that the polymorphism in the PTH gene would be a useful genetic marker for lower BMD and the susceptibility for osteoporosis.

Absorptiometry, Photon↗
PubMed1999

Association of radial bone mineral density with CA repeat polymorphism at the interleukin 6 locus in postmenopausal Japanese women.

Twin studies have shown strong correlations between bone mass and genetic factors. Some of the genes involved could regulate bone metabolism and bone formation and resorption, all processes that determine bone mass. One candidate gene, interleukin 6 (IL-6), has been implicated in the pathogenesis of bone loss because it stimulates osteoclasts. We investigated a possible association between the CA repeat polymorphism at the IL-6 gene locus and the bone mineral density (BMD) of radial bone in 472 postmenopausal Japanese women. Genotypes were classified into six groups according to the number of CA repeats present, from 13 to 18. BMD was expressed as adjusted BMD, which was the body mass index (BMI)- and age-adjusted average BMD. The 73 women who possessed an A1 allele (134 bp, containing 18 repeats of CA) had significantly lower adjusted BMD than those participants (n = 399) who did not carry an allele of that size (mean +/- SD values, 0.294 +/- 0.064 vs 0.312 +/- 0.061 g/cm2; P = 0.0221). This result suggests that genetic variation at the IL-6 gene locus is associated with some determinants of BMD in postmenopausal women.

Adenine Nucleotides↗
PubMed1999

Acute relapsing encephalopathy mimicking acute necrotizing encephalopathy in a 4-year-old boy.

A 4-year-old boy showed two episodes of encephalitis/encephalopathy involving disturbed consciousness, convulsion, and paresis associated with the elevated levels of protein and myelin basic protein of the cerebrospinal fluid. MRI studies of the brain revealed symmetrical lesions in the brain stem and thalami at the first episode, and additional lesions were found in the cerebellum involving both the gray and white matter in the second episode. The intensities of MRI lesions were low in T I and high in T2. These episodes were followed by an elevation of the anti-viral antibody titers, for influenza A virus during the first episode and for adenovirus during the second. In the second episode, intravenous methylprednisolone therapy resulted in rapid improvement of his neurological signs.

Brain↗
PubMed1999

High-level expression of maize phosphoenolpyruvate carboxylase in transgenic rice plants.

Using an Agrobacterium-mediated transformation system, we have introduced the intact gene of maize phosphoenolpyruvate carboxylase (PEPC), which catalyzes the initial fixation of atmospheric CO2 in C4 plants into the C3 crop rice. Most transgenic rice plants showed high-level expression of the maize gene; the activities of PEPC in leaves of some transgenic plants were two- to threefold higher than those in maize, and the enzyme accounted for up to 12% of the total leaf soluble protein. RNA gel blot and Southern blot analyses showed that the level of expression of the maize PEPC in transgenic rice plants correlated with the amount of transcript and the copy number of the inserted maize gene. Physiologically, the transgenic plants exhibited reduced O2 inhibition of photosynthesis and photosynthetic rates comparable to those of untransformed plants. The results demonstrate a successful strategy for installing the key biochemical component of the C4 pathway of photosynthesis in C3 plants.

Gene Dosage↗
PubMed1999

Glutathione S-transferase P1 (GSTP1) polymorphism in patients with chronic obstructive pulmonary disease.

BACKGROUND: Enzymes that contribute to the local detoxification in alveoli and bronchioles have an important role in the defence mechanism against tobacco smoke. It has been suggested that genetic susceptibility to smoking injury may confer a risk for the development of chronic obstructive pulmonary disease (COPD). The polymorphisms in glutathione S-transferase P1 (GSTP1), a xenobiotic metabolising enzyme, were investigated in patients with COPD. METHODS: Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were performed to genotype GSTP1 polymorphisms in exon 5 (Ile105Val) and exon 6 (Ala114Val). Blood samples were taken from 53 patients with COPD and 50 control subjects at the Tokyo University Hospital, the Juntendo University Hospital, and the Tokyo Kenbikyoin Clinic for use in the study. RESULTS: The proportion of GSTP1/Ile105 homozygotes was significantly higher in the patients with COPD than in the control subjects (79% vs 52%). The odds ratio for GSTP1/Ile105 homozygotes versus all other genotypes was 3.5 (95% CI 2.7 to 4.6) for COPD. Polymorphism at residue 114 of GSTP1 was not found in either group. CONCLUSIONS: Genetic polymorphism of exon 5 of GSTP1 may be associated with COPD because the GSTP1/Ile105 genotype is predominantly found in COPD. It is suggested that the GSTP1/Ile105 genotype may be less protective against xenobiotics in tobacco smoke.

Aged↗
PubMed1999

Vascularization into a porous sponge by sustained release of basic fibroblast growth factor.

Vascularization into a poly(vinyl alcohol) (PVA) sponge was investigated using basic fibroblast growth factor (bFGF). This growth factor was impregnated into biodegradable gelatin microspheres for its sustained release and then the bFGF-containing microspheres or free bFGF were incorporated into PVA sponges. Following subcutaneous implantation into the back of mice, the bFGF-containing gelatin microspheres induced vascularization in and around the sponge to a significantly greater extent than that of free bFGF from 3 days after implantation. Significant ingrowth of fibrous tissue into the sponge was also observed when bFGF-containing microspheres were added to the sponge in contrast to free bFGF. Tissue ingrowth occurred into the deeper portion of the sponge over time while it accompanied formation of new capillaries. Empty gelatin microspheres had no effect on vascularization and the level of fibrous tissue ingrowth into the sponge was similar to that of the control group. It was concluded that incorporation of gelatin microspheres containing bFGF into the PVA sponge was effective in prevascularization of the sponge pores.

Animals↗
PubMed1999

Extensive involvement of the myocardium and the cardiac conduction system in a case of Wegener's granulomatosis.

A 61-year-old female who had shown Raynaud's phenomenon and articular swelling for 10 years, was admitted to hospital because of fever of unknown origin (FUO) and dry cough. She was diagnosed by skin biopsy to have a collagen disease or overlap syndrome. Anemia developed rapidly and FUO persisted, but blood culture was negative. Although indomethacin and prednisolone were administered for the progression of clinical signs and symptoms, severe dyspnea developed, resulting in bradycardia, followed by recurrent episodes of ventricular tachycardia. In spite of extensive treatment for her arrhythmia she died on the 9th hospital day. An autopsy revealed generalized Wegener's granulomatosis with extensive cardiac involvement. Necrotizing angitis and severe granulomatous inflammatory foci affected characteristically the common bundle of His and right bundle branch in addition to the ordinary myocardium.

Electrocardiography↗
PubMed1999

[Characteristics of the medical status and living conditions of the homeless registered as tuberculosis patients in Nagoya City].

An Investigation by questionnaire was conducted in 1996 to know the tuberculosis (TB) status and living conditions of 50 homeless people registered as TB patients at one of Nagoya city's 16 health centers. 1. All patients had one or more symptoms of TB, 64% of them showed positive TB bacilli on smear, and 35.3% of them had a previous history of TB treatment. However, only 15.2% suspected they had TB at the onset of symptoms. 2. Main reasons of seeking medical treatment: 28.6% arrived by ambulance after falling down from exhaustion, 25.7% had consulted with welfare agencies after the onset of symptoms, and 20.0% had been diagnosed during the treatment of other diseases. 3. When they were admitted to the hospital they had many concerns: 29.0% loss of income, 19.4% living expenses, 19.4% smoking prohibition, 12.9% admission fee, and 9.7% privacy. 4. They lived in the following: 42.9% construction camps, 20.0% parks or streets, 17.1% single room occupancy hotels, 17.1% daily or monthly paid apartments, and 11.4% sauna baths. 5. Past medical histories of the subjects included 40.6% injuries by labor accidents, and 25.0% stomach ulcers. Current diseases were 15.6% mental diseases, 15.6% liver diseases, 15.6% diabetes mellitus, and 9.4% alcoholic dependence. Seventy percent of them consumed alcohol daily (average pure ethanol 125 ml per day). 6. From the results outlined above, the following proposals relating to TB control of the homeless should be considered. 1) Educating the homeless as to the need for a health check when TB symptoms are present. 2) Opening a clinic for the homeless for easy access to consultation on TB. 3) Directly observed therapy short-course, for TB in the homeless. 4) Health examination of the employees of single-room occupancy hotels and sauna baths which are used frequently by the homeless. 5) A fundamental countermeasure to deal with alcoholic dependency among the homeless.

Female↗
PubMed1999

[Neurophysiological correlates of learning disabilities in Japan].

In the present study, we developed a new event-related potentials (ERPs) stimulator system applicable to simultaneous audio visual stimuli, and tested it clinically on healthy adults and patients with learning disabilities (LD), using Japanese language task stimuli: hiragana letters, kanji letters, and kanji letters with spoken words. (1) The origins of the P300 component were identified in these tasks. The sources in the former two tasks were located in different areas. In the simultaneous task stimuli, a combination of the two P300 sources was observed with dominance in the left posterior inferior temporal area. (2) In patients with learning disabilities, those with reading and writing disability showed low amplitudes in the left hemisphere in response to visual language task stimuli with kanji and hiragana letters, in contrast to healthy children and LD patients with arithmetic disability. (3) To evaluate the effect of methylphenidate (10 mg) on ADD, paired-associate ERPs were recorded. Methylphenidate increased the amplitude of P300.

Acoustic Stimulation↗
PubMed1998

Cloning of a cDNA encoding an importin-alpha and down-regulation of the gene by light in rice leaves.

The import of nuclear proteins into nuclei begins with recognition of nuclear localization signal-harboring proteins and binding to a nuclear pore targeting complex. A cDNA for an importin-alpha protein, a subunit of the complex, was isolated from rice plants. The amino acid sequence deduced from the nucleotide sequence of the cDNA exhibited a high homology to those of importin-alpha proteins from many organisms such as Arabidopsis thaliana, Saccharomyces cerevisiae, human, mouse, Xenopus laevis and Drosophila melanogaster. Down-regulation of the transcription by light was shown in the leaves of light- and dark-grown seedlings by RNA blot analysis. The down-regulation was specific to leaves, whereas no light effect was observed in root tissues or calli, in which higher levels of the transcript were detected.

Amino Acid Sequence↗
PubMed1998

A novel importin alpha from rice, a component involved in the process of nuclear protein transport.

In eukaryotes, nuclear proteins that are transported into nuclei have nuclear localization signals (NLSs), which are recognized by proteins called importin alpha. We isolated a rice cDNA, #61L, and the corresponding gene that encodes a protein, which shows significant homology to the importin alpha. Although the encoded protein had only 23-27% amino acid identity to the importin alphas from various organisms including plants, the fusion protein with glutathione S-transferase showed a specific binding activity to the NLS of SV40 T-antigen. These results suggest that the rice #61L protein is a novel importin alpha in plants.

Amino Acid Sequence↗
PubMed1998

Polymorphism of insulin-like growth factor I gene and bone mineral density.

The polymorphism of insulin-like growth factor-I (IGF-I) gene was examined in Japanese postmenopausal women to analyze the genetic background for osteoporosis. In this study, the dinucleotide (cytosine-adenine; CA) repeat sequence lying upstream of the transcription initiation site of this gene was examined. We named the most frequent allele including (CA) 19 as J allele. There were 6 alleles (J-4 containing 17 CA repeats: (CA)17, [J-2 (CA)18, J (CA)19, J + 2 (CA)20, J + 4 (CA)21, J + 6 (CA)22]) in the Japanese population. The genotype distribution was different from that of Caucasians. There was no different in bone mineral density (BMD) between the group with one or two alleles of each genotype and that without that genotype. When we separate the subjects into three groups having two alleles, one allele, and no alleles, the three subjects who possess the allele 'J-2' in both strands had low BMD (Z score of L2-4; -1.24 +/- 0.56, total body; -0.943 +/- 0.59, mean +/- SE). On the other hand, sequence of IGF-I gene in this study was different from reported sequence of IGF-I gene; that was 2 base pair (bp) deletion following 3'end of CArepeat (-645adenine/-646guanine). The present study showed that there was no association between the microsatellite polymorphism of IGF-I gene and BMD in Japanese postmenopausal women, but some possibility remains that the microsatellite polymorphism of IGF-I gene is useful to detect a kind of particular osteoporosis.

Absorptiometry, Photon↗