Biomedical subjects

Y Yamano

Publications and source records attributed to Y Yamano.

At least 55 records · Page 3Linked to original sources

PubMed2000

Low-intensity pulsed ultrasound accelerates bone maturation in distraction osteogenesis in rabbits.

We investigated the effects of low-intensity pulsed ultrasound on distraction osteogenesis in a rabbit model. Callotasis of the right tibia was performed in 70 male Japanese white rabbits using mini-external fixators. In the first part of the study in 64 animals using normal distraction (waiting period seven days; distraction rate 0.5 mm/12 hours; distraction period ten days), we evaluated the distraction site by radiography, measurement of the bone mineral density (BMD), mechanical testing, and histology. In the second part in six rabbits using fast distraction (waiting period 0 days; distraction rate 1.5 mm/12 hours; distraction period seven days) the site was evaluated radiologically. Half of the animals (35) had received ultrasound to their right leg (30 mW/cm2) for 20 minutes daily after ceasing distraction (ultrasound group), while rigid fixation only was maintained in the other half (control group). With normal distraction, the hard callus area, as shown by radiography, the BMD, and the findings on mechanical testing, were significantly greater in those receiving ultrasound than in the control group. Histological analysis showed no tissue damage attributable to exposure to ultrasound. With fast distraction, immature bone regeneration was observed radiologically in the control group, while bone maturation was achieved in the ultrasound group. We conclude that ultrasound can accelerate bone maturation in distraction osteogenesis in rabbits, even in states of poor callotasis.

Animals↗

PubMed2000

Tibiofemoral movement 3: full flexion in the living knee studied by MRI.

We studied active flexion from 90 degrees to 133 degrees and passive flexion to 162 degrees using MRI in 20 unloaded knees in Japanese subjects. Flexion over this arc is accompanied by backward movement of the medial femoral condyle of 4.0 mm and by backward movement laterally of 15 mm, i.e., by internal rotation of the tibia. At 162 degrees the lateral femoral condyle lies posterior to the tibia.

Adult↗

PubMed2000

Expression of differentiated phenotype in the pseudo-tendon sheath formed by a silicon rod.

We examined the cartilaginous gene expression in the inner layer of the pseudo-tendon sheath formed by an silicon rod. While cartilaginous gene expression was not detected in the outer layer of the tissue, gene expressions of aggrecan and type II collagen were detected in the inner layer of the the newly formed pseudo-tendon sheath around the silicon rod. Relative expression of aggrecan and Type II collagen were 0.15 and 0.28, respectively, compared to that of GAPDH. The expression of type II collagen was 0.57-folds of that of type I collagen. In these tissues, a sliding surface was formed by a silicon rod and the surrounding tissues, and its mechanical stress may induce cartilaginous gene expression. Mechanical stress together with various growth factors and cytokines may be critically important for the formation of more physiological tendon sheath structures. Therefore, we will further examine the changes detected in the tissues and evaluate mechanical stress for formation of the tendon sheath.

Adult↗

PubMed2000

Effects of mechanical stress on expression of differentiated phenotypes of chondrocytes.

In the patients with dislocated hip arthropathy, cartilage gene expression was confirmed in weight-bearing inner layer tissues of the joint capsule. Because these inner layer tissues of the joint capsule formed joint-like structures with the femoral head for a long period, cartilaginous genes may have been expressed in the weight-bearing inner surface of the joint capsule. There was a difference in expression of the genes between weight-bearing and non-weight-bearing parts. From a quantitative comparison between GAPDH and aggrecan gene expression, aggrecan gene expression was 30-fold higher in the weight-bearing part than in the non-weight-bearing part. Aggrecan gene expression was not detected in outer layer tissues of the joint capsule. Type II collagen and TGF-beta genes were also detected, and both genes showed differences in expression between the weight-bearing and non-weight-bearing parts like the aggrecan gene. This may have been because mechanical stress caused cartilaginous differentiation in undifferentiated mesenchymal tissues in the inner layer of the joint capsule. Cell differentiation and proliferation caused by mechanical stress are indicate key role to osteoarticular tissues, and it is considered important for orthopedic treatment to evaluate the process in detail.

Aged↗

PubMed2000

Reconstruction of a double nail deformity: a case report.

We report the successful reconstruction of a double nail deformity after fingertip injury. Double nail growth is rather rare. In our case it was not of congenital origin. Double nail deformity results from implantation of the nail matrix associated with damage to the finger tip. We excised the second nail and reconstructed the remaining nail bed using a part of the excised one. The vertical growth of the first nail was also corrected. Four months later, successful regeneration of the nail was observed.

Finger Injuries↗

PubMed2000

A preliminary evaluation of intra- and interindividual variations of hOGG1 messenger RNA levels in peripheral blood cells as determined by a real-time polymerase chain reaction technique.

The hOGG1 (8-oxoguanine-DNA glycosylase) gene may contribute to further understanding of the relation between oxidative DNA damage and carcinogenesis. A real-time PCR technique was used to determine mRNA levels in peripheral blood cells to assess the possibility of using hOGG1 mRNA as a biomarker in epidemiological studies. To evaluate the intra- and interindividual variation of hOGG1 mRNA levels in peripheral blood cells, we measured them in five healthy nonsmokers three times over a 1-year period. The beta-actin mRNA level in each subject was set equal to 100, and the levels of hOGG1 mRNA were found to range from 1.6-17.6. The intraindividual variation range was 1.8-6.4. Although the difference in the mRNA levels between the sampling dates was not significant (P = 0.73), a significant difference in mRNA levels was found between the subjects (P < 0.01). The subjects seemed to fall into groups according to their individual levels. This preliminary study may provide initial information on the hOGG1 mRNA level of peripheral blood cells as a biomarker in epidemiological studies on oxygen radicals, oxygen radical-related agents, and cancer.

Adult↗

PubMed2000

Callotasis for post-traumatic shortening and deformity of leg.

We have been performed callotasis, including hemicallotasis, in cases of more than 30 mm limb lengthening and more than 15 degrees angular deformity. There were 21 cases in this series. The mean age was 29.8 years old. Ilizarov external fixator (EF) was used in 13 cases and Orthofix EF in 8. The operation site was femur in 12 cases and tibia in 9 cases. Pre-existed complications were noted to occur in 10 cases. Callotasis was indicated in 17 cases, and the average length gain was 28.4 mm. Hemicallotasis was indicated in 5 cases, and the mean degree of correction angle was 18 degrees. Among available types of EF, Orthofix EF was suitable for proximal femoral callotasis, while Ilizarov EF was suitable for corrective deformity using hemicallotasis and tibial callotasis. The bone healing process of callotsis was better in the absence than presence of pre-existed complication. Also, we performed bone transportation using Ilizarov EF in cases of pseudoarthrosis with leg shortening and in all cases where bone grafting was unnecessary.

Adolescent↗

PubMed1999

Cartilaginous differentiation in the joint capsule.

The proliferation and differentiation of cells are greatly influenced by their environment. Many growth factors and cytokines are reported to be environmental factors that affect the proliferation and differentiation of cells. Mechanical stress is also considered to influence these physiological reactions. The joint capsule, which is a part of the joint tissue, plays a very important role in the stability of the joint and in maintaining the intracapsular phenomenon. In patients with dislocated hip arthropathy, this capsule is involved in the weightbearing function by forming a sliding surface between the capsule and the femoral head articular cartilage. The surface of the tissue macroscopically shows cartilaginous change, which indicates cartilaginous differentiation caused by mechanical stress. We examined the cartilage-specific proteoglycan component, which is composed of cartilaginou matrix at the differentiation site. We investigated proteoglycan production, molecular size, and the gene expression of cartilaginous substrate. At the inner layer of the weightbearing area of the joint capsule, proteoglycan production was significantly higher than that of other noncartilaginous tissue. We also identified the gene expression of cartilaginous proteoglycan using the reverse transcription polymerase chain reaction (RT-PCR) method.

Aggrecans↗

PubMed1999

Minimum structure of peptidoglycan required for induction of antibacterial protein synthesis in the silkworm, Bombyx mori.

Various peptidoglycan fragments, different in mode of cross-linking and molecular size, were isolated, and the elicitor activity was tested for induction of antibacterial protein synthesis in larvae of Bombyx mori. Linear uncross-linked peptidoglycans from Bacillus licheniformis and Micrococcus luteus were effective elicitors, similar to the directly cross-linked peptidoglycan from B. licheniformis cell wall. The fragments of uncross-linked peptidoglycan with a sugar chain length of four or more were active elicitors, but the disaccharide unit had no elicitor activity. The minimum structure of peptidoglycan required for induction of antibacterial protein synthesis was determined to be two repeating N-acetylglucosamine-N-acetylmuramic acid units with peptide side chains.

Animals↗

PubMed1999

Determination of mechanical properties of impacted human morsellized cancellous allografts for revision joint arthroplasty.

This paper deals with the characterization of mechanical properties of impacted morsellized cancellous allograft (IMCA) produced by dynamic compaction of allograft femoral heads ground by commercially available bone mills, i.e. rotating rasp and reciprocating type bone mills. Various ranges and profiles of particle size in the graft aggregates were obtained using these bone mills, and the effect of number of compaction as well as the distribution of particle sizes on the mechanical properties of IMCA under quasistatic compression and shear loading conditions was discussed. The morsellized cancellous allograft prepared by the reciprocating type bone mill showed a broad distribution of particle sizes, and gave IMCA superior mechanical properties to the graft with a more uniform size distribution, or prepared by the rotating rasp type bone mills. The increase of number of compaction also improved the mechanical properties of IMCA in compression.

Journal Article↗

PubMed1999

Differences between changes in serum thyrotropin-binding inhibitory antibodies and thyroid-stimulating antibodies in the course of antithyroid drug therapy for Graves' disease.

There has recently been controversy regarding whether the measurement of thyrotropin-binding inhibitory antibodies (TBIAb) is useful in the management of Graves' disease. Another method of assessing Graves' disease by measuring adenylate cyclase activity in thyroid cells, known as thyroid-stimulating antibodies (TSAb), differs from TBIAb not only in terms of assay but also in immunoglobulin type according to recent studies. In this study, the concentrations of TBIAb and TSAb were compared in serial serum samples collected from 29 patients with Graves' hyperthyroidism during 12 months of antithyroid drug therapy. Before therapy, there was a correlation between TBIAb and TSAb (r = 0.59). The radioactive iodine uptake (RAIU) was not significantly correlated with either TBIAb or TSAb (r = 0.20 and r = 0.29, respectively), and the serum free thyroxine (FT4) concentration was also not significantly correlated with either TBIAb or TSAb (r = 0.06 and r = 0.22, respectively). In patients with Graves' ophthalmopathy, TSAb levels were higher than in patients without ophthalmopathy (1015%+/-851% vs. 456%+/-323%, p<0.01), but the TBIAb levels were not significantly different. After antithyroid treatment, TBIAb did not decrease significantly (from 42.1%+/-20.8% to 20.5%+/-19.5%, p = 0.29). On the other hand, TSAb was significantly decreased after 12 months of treatment (from 649%+/-611% to 294%+/-205%, p< 0.05). These findings indicate that TBIAb and TSAb are not identical, and that TSAb has a closer relationship to thyroid function than TBIAb. In the clinical setting, determination of the serum TSAb level may provide a more accurate index of the thyroid status in Graves' disease patients receiving antithyroid therapy.

Adult↗

PubMed1999

Localization of metallothioneins-I & -II and -III in the brain of aged dog.

Localization of metallothionein (MT) -I & -II and MT-III and its significance in the brain aging in dogs were examined using immunohistological and molecular pathological techniques. MT-I & -II immunohistochemistry showed positive staining in the hypertrophic astrocytes throughout the aged dog brains; these MT-I & -II immunoreactive astrocytes were predominant in the cerebral cortex and around the blood vessels in the brain. These findings dominated in the brain regions with severe age-related morphological changes. In situ hybridization using MT-I mRNA riboprobes also demonstrated signals for MT-I mRNA in these hypertrophic astrocytes. Immunohistochemistry using a guinea pig antiserum against a synthetic polypeptide of canine MT-III demonstrated positive MT-III immunoreactivity predominantly in neurons in the Zn-rich regions such as hippocampus and parahippocampus. The findings were supported by in situ hybridization using MT-III mRNA riboprobes. Both MT-III immunoreactivity and signals for MT-III mRNA were demonstrated in neurons in the brain regardless of the intensity of the age-related changes. These results suggest, first, MT-I & -II may be induced in relation to the progress of the age-related morphological changes in the brain, playing an important role in the protection of the brain tissue from the toxic insults responsible for the brain aging, and second, MT-III may play a role in maintenance of Zn-related essential functions of the brain.

Aging↗

PubMed1999

Estrogen supplementation for bone dematuration in young epileptic man treated with anticonvulsant therapy; a case report.

We encountered a young man treated with anticonvulsant therapy who had greatly reduced bone mineral density. An 18-year-old man was admitted to our hospital for shoulder pain and further evaluation of decreased bone mineral density. He had been treated with anticonvulsants, including phenytoin, phenobarbital, valproic acid and zonisamide for seizures. Although testosterone was found within the normal range for adult men, the serum estrogen concentration was below the detection limit (< 10 pg/ml) and his wrist epiphyses were not yet closed. After 10 months of treatment with the conjugated estrogen, both his height and weight showed improvement, while his bone mineral density and bone age were increased. These findings suggested that estrogen therapy had a significant effect on his skeletal growth and bone maturation in man. This is the first report showing the beneficial effect of estrogen supplementation in an epileptic man receiving treatment with anticonvulsants.

Adult↗

PubMed1999

Isolation of 9Z beta-carotene from Dunaliella bardawil and its stereoselective synthesis.

An isolation of 9Z beta-carotene from Dunaliella bardawil was accomplished by low-pressure column chromatography with Ca(OH)2 column. Furthermore, it was stereoselectively synthesized by Wittig reaction between the C10-phosphonium salt 2 and 9Z beta-apo-8'-carotenal 1, which was prepared by Emmons-Horner reaction of 9Z beta-ionylideneacetaldehyde 3 with phosphonates 6 and 7 or 8a and 9.

Chlorophyta↗

PubMed1999

Anteroposterior and rotational movement of femur during knee flexion.

This study was designed to analyze anteroposterior and rotational movement of femoral condyles during knee flexion from 15 degrees to 90 degrees using magnetic resonance imaging. After a pilot study, scans were made in 10 healthy male Japanese volunteers. When centers of the circular profiles of posterior femoral condyles were used as reference points, the medial and lateral femoral condyles displaced posteriorly 1.9 +/- 0.8 mm and 2.3 +/- 0.5 mm, respectively (mean +/- standard error). Duplicate examinations on two separate occasions revealed the accuracy of this procedure was in the range of 1 to 2 mm. These results have confirmed that femoral rollback occurs in the unloaded normal knee during flexion from 15 degrees to 90 degrees, but its magnitude is small (2 mm). The results obtained in this in vivo measurement of anteroposterior movement of the femoral condyles have relevance for total knee replacement design.

Adult↗

PubMed1999

Effect of sliding locus on subsurface crack formation in ultra-high-molecular-weight polyethylene knee component.

The objective of this study was to evaluate the effect of sliding locus on fatigue destruction of ultra-high-molecular-weight polyethylene (UHMWPE) in order to design a durable total knee arthroplasty (TKA) articulation. Two-dimensional sliding fatigue testing was performed under two simplified patterns of articulating interface sliding locus. Scanning acoustic tomography (SAT) was used for observation of subsurface cracks in UHMWPE specimens. A high rate of subsurface crack formation was observed when the movement was reciprocated on two different loci, in contrast with that on a single linear locus. This finding suggests that crack formation or propagation in UHMWPE components is accelerated not only by the compressive stress but also by complicated articulating movement locus.

Biocompatible Materials↗

PubMed1999

Expression of cartilage specific genes by human capsular cartilaginous cells.

The amount of proteoglycan production in tissue that was considered to have cartilaginously differentiated due to mechanical stress and cartilage specific gene expression were investigated. The inner layer of the joint capsule which forms a sliding surface with the femoral head in the case of dislocated hip arthoropathy showed higher proteoglycan production compared to that in the surrounding non-cartilaginous tissue. On examining gene expression, although large cartilaginous proteoglycan is originally absent in this region, gene expression of aggrecan and versican which are able to bind to hyaluronan was observed. Further, gene expression of decorin and link protein was also examined. These findings in the inner layer of joint capsule forming sliding surface with the femoral head suggested the importance of mechanical stress in cartilaginous differentiatiog of mesenchymal tissue.

Cartilage↗

PubMed1998

Measurements of zeta potentials of particulate biomaterials in protein-rich hyaluronan solution with changes in pH and protein constituents.

This study was undertaken to determine the zeta potentials of particulate biomaterials in three types of protein-rich hyaluronan solution with changes in pH; a microelectrophoretic method was used. For the purpose of determining the pH value of synovial fluid in various inflammatory conditions, we collected synovial fluid samples from joints with osteoarthritis (OA), rheumatoid arthritis (RA), and those undergoing revisions arthroplasties. The mean values of the pH in the synovial fluid from joints with OA, RA, and revision arthroplasty were shown to be 7.9, 7.5, and 8.1, respectively. The pH-zeta potential curves obtained differed, depending on the biomaterial and the medium. Addition of gamma-globulin to the medium reduced the absolute value of the zeta potentials of some of the biomaterials. The findings of this study suggest that the electrophoretic behaviors of the particulate biomaterials tested in this study are affected by the protein constituents of and pH changes in protein-rich synovial fluid. The values we obtained will be useful as reference standards and will also aid in the study of the surface phenomena of biomaterials.

Biocompatible Materials↗