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Biomedical subjects

S Miyauchi

Publications and source records attributed to S Miyauchi.

At least 19 recordsLinked to original sources
PubMed2003

Hyaluronan synthase in trabecular meshwork cells.

BACKGROUND/AIMS: Hyaluronan is present in the trabecular meshwork where it is involved in the pathophysiology of aqueous outflow environment. In this study, the expression and regulation of hyaluronan synthase (HAS), which is the enzyme synthesising hyaluronan, in trabecular meshwork cells were investigated. METHODS: Cultured bovine trabecular meshwork cells (BTMCs) were used. HAS expression in BTMCs was examined by RT-PCR. The effects of transforming growth factor beta (TGF-beta) and platelet derived growth factor BB (PDGF-BB) on HAS expression in BTMCs were examined by quantitative RT-PCR. The HAS2 expression by TGF-beta and PDGF-BB at the protein level was also confirmed immunohistochemically. The production of hyaluronan from BTMCs was detected by high performance liquid chromatography (HPLC). RESULTS: Three HAS isoforms were expressed in BTMCs at the mRNA level. Among HAS isoforms, only the expression of HAS2 mRNA was increased by the administration of TGF-beta or PDGF-BB. HAS2 upregulation by these growth factors was also confirmed at the protein level. Further, hyaluronan production from BTMCs was stimulated by TGF-beta or PDGF-BB. CONCLUSION: Expression of HAS in trabecular meshwork may maintain the hyaluronan content in the aqueous outflow pathway. Its production is regulated by TGF-beta and PDGF-BB. The regulation of the expression of HAS in trabecular meshwork might be useful for modulating the aqueous outflow environment.

Animals↗
PubMed2001

Enzymatic hydrolysis of poly(lactide)s: effects of molecular weight, L-lactide content, and enantiomeric and diastereoisomeric polymer blending.

Nonblended poly(L-lactide) (PLLA) films having different molecular weights and nonblended poly(lactide) (PLA) films, enantiomeric blend films from PLLA and poly(D-lactide) (PDLA), and diastereoisomeric blend films of poly(DL-lactide) (PDLLA) with either PLLA or PDLA, having different L-lactide (LLA) contents (X(LLA)s) in the range of 0-0.99, were amorphous made by melt-quenching. The effects of molecular weight, X(LLA), and average L- and D-lactyl unit sequence length (l(L) and l(D), respectively) on the enzymatic hydrolysis of the films were investigated in the presence of proteinase K. The enzymatic hydrolysis rate (R(EH)) of PLLA estimated by gravimetry increased monotonically with the inverse of number-average molecular weight (M(n)). The extrapolation of R(EH) of PLLA to M(n)(-1) = 0, where no exo-chain-scission takes place, gave a positive R(EH) value (1.75 microg/(mm(2).h)), meaning that the enzymatic hydrolysis of PLLA proceeds via both endo- and exo-chain-scission. The R(EH) of the nonblended films as well as the enantiomeric and diastereoisomeric blend films decreased monotonically with the decease in X(LLA) and finally became zero for X(LLA) below 0.3. The R(EH) values of the blend films of PLLA and PDLLA with PDLA (l(D) = infinity) were lower than expected, while the R(EH) values of the blend films of PLLA with PDLLA (l(D) = 4) agreed completely with the expected values. These results reveal that the nonblended PLA films are enzymatically hydrolyzable when X(LLA) and l(L) are higher than 0.3 and 3, respectively, and l(D) is lower than 10 and that the presence of long D-lactyl unit sequences (l(D) > 4) as in PDLA hinders the enzymatic hydrolysis of long L-lactyl unit sequences even when long D- and L-lactyl unit sequences are present in the different molecules.

Biocompatible Materials↗
PubMed2001

Effects of chondroitin sulfate on colitis induced by dextran sulfate sodium in rats.

Chondroitin sulfate (CS) is currently marketed as a therapeutic drug for neurodynia, lumbago and arthrodynia. Recently, many clinical studies have demonstrated the therapeutic effects of orally administered CS against diseases with inflammation. Furthermore, these reports suggest CS plays an important role in the protection of the base of ulcers and has anti-inflammatory activity. We investigated the effects of CS against dextran sulfate sodium (DSS)-induced rat colitis. Rats were given 3% DSS solution for 10 days ad libitum. CS and 5-aminosalicylic acid (5-ASA) were orally administered daily. The doses of the CS groups were 20 or 100 mg/kg and that for the 5-ASA group was 100 mg/kg. Evaluations were made of bloody stools, areas of erosion and hematological data. CS improved the symptoms of bloody stools, erosion and increase of white blood cells. Especially, CS (100 mg/kg) group showed markedly more improvement than the 5-ASA group. We think that the major mechanism of the therapeutic effects of CS are the prevention of tissue damage by the protection of digestive mucosa and anti-inflammatory effects. Therefore, CS may have therapeutic value for alimentary tract diseases such as inflammatory bowel disease or ulcer.

Animals↗
PubMed2001

Investigation of the short-term effect of chemonucleolysis with chondroitinase ABC.

Chondroitinase ABC (C-ABC) is expected to be a novel agent for chemonucleolysis. The effect of C-ABC was investigated by magnetic resonance (MR) and radiograph. C-ABC was administered into the lumbar intervertebral disks on the clinically normal beagles (n=5), in a dose of 50 microl (12.5 units as C-ABC). MR scans were performed pre-dose, and 1, 3, 7, 14 and 28 days after administration of C-ABC, and the signal intensity (SI) of the nucleus pulposus was measured. Radiographs were taken pre-dose, and 1, 2, 3, 4, 5, 6, 7, 14 and 28 days post-dose, to evaluate narrowing of the disk space in terms of height index (HI). In addition, the quantity of the chondroitin sulfate (CS) and the hyaluronic acid (HA) in the nucleus pulposus were measured by high performance liquid chromatography on day 28 after dosing. SI and HI continuously decreased, following the injection to 37.1% and 78.9% of the pre-dose values, respectively. Statistically significant differences (p<0.01) were observed between the C-ABC group and the control group in the respects on day 1 post-dose. CS and HA contents of the nucleus pulposus were noted to be significantly decreased on day 28 (p<0.01) in the treated group. This agent proved to degenerate proteoglycans in the nucleus pulposus, thus progressively reducing the interdiskal pressure from day 1 post-dose onwards. It is concluded that C-ABC is expected to afford its efficacy from early in the course of chemonucleolysis.

Animals↗
PubMed2001

Changes in molecular weight of hyaluronan and hyaluronidase activity in uterine cervical mucus in cervical ripening.

BACKGROUND: This study was undertaken to investigate changes in the forms of hyaluronan and hyaluronidase activity in cervical mucus during cervical ripening. METHODS: Uterine cervical mucus was obtained from 57 pregnant women (25 at preterm gestation, ten at term gestation, 11 within 1 week before labor, and 11 during the first stage of labor). We determined 1) concentration of hyaluronan, 2) hyaluronidase activity, and 3) molecular weight of hyaluronan in cervical mucus. Data are presented as mean and range. RESULTS: The hyaluronan concentration in mucus in the 1st stage of labor (1.58 microg/ml, 0.46-23.96) was significantly (p<0.05) higher than that in all other groups (preterm: 0.29, 0.10-0.88; term: 0.24, 0.11-0.80; within 1 week before labor: 0.30, 0.18-0.62). Hyaluronidase activity both within 1 week before labor group (3.03 min., 1.12-3.95) and in 1st stage of labor group (3.52, 0.43-5.15) was significantly (p<0.05) higher than that in preterm group (1.70, 0.00-5.47). The molecular weight of hyaluronan in cervical mucus in the 1st stage of labor (0.97x106, 0.86-1.41) was significantly (p<0.05) lower than in the preterm and term groups (preterm: 1.60, 1.21-2.20, term: 1.41, 1.21-2.20). There was a significant correlation between hyaluronidase activity and molecular weight of hyaluronan (p<0.05, r=-0.41, n=23). CONCLUSION: These findings suggest that either hyaluronidase or low-molecular weight hyaluronan could be one of the most important regulators in the process of cervical ripening.

Analysis of Variance↗
PubMed2001

Effects of sodium hyaluronate on epithelial healing of the vesical mucosa and vesical fibrosis in rabbits with acetic acid induced cystitis.

PURPOSE: To evaluate the effect of sodium hyaluronate on epithelial healing of the vesical mucosa and vesical fibrosis, and clarify the effect of the sodium hyaluronate solution concentration, we administered sodium hyaluronate in the bladder of rabbits with acetic acid induced cystitis. MATERIALS AND METHODS: Sodium hyaluronate at 3 concentrations (0.1%, 0.2% and 0.4%) was injected intravesically into rabbits with cystitis. Seven days after injection the effect of sodium hyaluronate was evaluated by bladder capacity measurement. Furthermore, the epithelial defective region of the mucosal membrane and bladder dry weight were determined and the condition of the epithelial membrane and extent of fibrosis were examined histologically. RESULTS: In all sodium hyaluronate treated groups a significant improvement in bladder capacity was observed compared to controls. In addition, a significant reduction was noted in the area of the epithelial defective region in the groups treated with 0.2% or 0.4% sodium hyaluronate and a significant decrease was noted in bladder dry weight in the group treated with 0.4% sodium hyaluronate. Histological examination revealed accelerated epithelial healing of the vesical mucosa and inhibited vesical fibrosis in the group treated with 0.4% sodium hyaluronate. CONCLUSIONS: Our findings suggest that sodium hyaluronate is effective for promoting epithelial healing of the vesical mucosa and inhibiting vesical fibrosis.

Acetic Acid↗
PubMed2000

Body image as a visuomotor transformation device revealed in adaptation to reversed vision.

People adapt with remarkable flexibility to reversal of the visual field caused by prism spectacles. With sufficient time, this adaptation restores visually guided behaviour and perceptual harmony between the visible and tactile worlds. Although it has been suggested that seeing one's own body is crucial for adaptation, the underlying mechanisms are unclear. Here we show that a new representation of visuomotor mapping with respect to the hands emerges in a month during adaptation to reversed vision. The subjects become bi-perceptual, or able to use both new and old representations. In a visual task designed to assess the new hand representation, subjects identified visually presented hands as left or right by matching the picture to the representation of their own hands. Functional magnetic resonance imaging showed brain activity in the left posterior frontal cortex (Broca's area) that was unique to the new hand representations of both hands, together with activation in the intraparietal sulcus and prefrontal cortex. The emergence of the new hand representation coincided with the adaptation of perceived location of visible objects in space. These results suggest that the hand representation operates as a visuomotor transformation device that provides an arm-centred frame of reference for space perception.

Adaptation, Physiological↗
PubMed2000

What and when: parallel and convergent processing in motor control.

Successful motor behavior requires making appropriate response (response selection) at the right time (timing adjustment). Earlier psychological studies have suggested that the response selection and timing adjustment processes are performed serially in separate stages. We tested this hypothesis using functional magnetic resonance imaging. The subjects performed a choice reaction time task in four conditions: two (on-line response selection required or not) by two (on-line timing adjustment required or not). We found that the neural correlates for the two processes were indeed separate: the anterior medial premotor cortex (presupplementary motor area) was selectively active in response selection, whereas the cerebellar posterior lobe was selectively active in timing adjustment. However, the functional separation was only partial in that the lateral premotor cortex and the intraparietal sulcus were active equally for response selection and timing adjustment. The lateral premotor cortex was most active when both processes were required, suggesting that it integrates the information on response selection and the information on timing adjustment; alternatively, it might contribute to the allocation of attentional resources during dual information processing. The intraparietal sulcus was equally active when either response selection or timing adjustment was required, suggesting that it modifies, rather than integrates, these processes. Furthermore, our results suggest that these activations related to response selection and timing adjustment were distinct from sensory or motor processes.

Adult↗
PubMed2000

Human cerebellar activity reflecting an acquired internal model of a new tool.

Theories of motor control postulate that the brain uses internal models of the body to control movements accurately. Internal models are neural representations of how, for instance, the arm would respond to a neural command, given its current position and velocity. Previous studies have shown that the cerebellar cortex can acquire internal models through motor learning. Because the human cerebellum is involved in higher cognitive function as well as in motor control, we propose a coherent computational theory in which the phylogenetically newer part of the cerebellum similarly acquires internal models of objects in the external world. While human subjects learned to use a new tool (a computer mouse with a novel rotational transformation), cerebellar activity was measured by functional magnetic resonance imaging. As predicted by our theory, two types of activity were observed. One was spread over wide areas of the cerebellum and was precisely proportional to the error signal that guides the acquisition of internal models during learning. The other was confined to the area near the posterior superior fissure and remained even after learning, when the error levels had been equalized, thus probably reflecting an acquired internal model of the new tool.

Adult↗
PubMed2000

Activation of the cerebellum in co-ordinated eye and hand tracking movements: an fMRI study.

Dysfunction of the cerebellum leads to significant deterioration of movements performed under visual guidance and of co-ordinated eye and hand movement. Visually guided tracking tasks combine both of these control features, as the eyes and hand together track a visual target. To better understand the involvement of the cerebellum in tracking tasks, we used functional magnetic-resonance imaging to study the activation of cerebellar structures in visually guided tracking movements of the eye and hand. Subjects were tested performing ocular tracking, manual tracking without eye movement or combined eye and hand tracking of a smoothly moving visual target. Three areas were activated in the cerebellum: a bilateral region in the ansiform lobule of the lateral hemisphere, a region in the ipsilateral paramedian lobule and a region in the oculomotor vermis. The ansiform and paramedian areas were most strongly activated by hand movement, although the vermal site was also active. The reverse was found for ocular tracking, with predominantly vermal activation. Activation of these cerebellar cortical areas related to movement of eyes or hand alone was significantly enhanced when the subjects performed co-ordinated eye and hand tracking of a visual target. These results provide the first direct evidence from a functional-imaging study for cerebellar activation in eye and hand co-ordination.

Analysis of Variance↗
PubMed2000

Ectopic calcification following tibial fracture: property analysis.

We present a patient whose ectopic calcification following deep posterior compartment syndrome was studied by electron microscopy, chemical analyses, and X-ray diffraction. The patient complained of a toe flexion deformity following a tibial fracture which he sustained 18 years earlier. Damage to the peroneal artery was demonstrated by magnetic resonance angiography, suggesting that the patient had had deep posterior compartment syndrome in the past. A large radiopaque mass, identified in the flexor hallucis longus muscle by radiographs and computed tomography, was resected, resulting in a dramatic improvement of the toe deformity. The resected material was analyzed in detail. It included no osseous tissue, and was not birefringent under a polarizing microscope, being compatible with ectopic calcification rather than ossification. On electron microscopy the material was found to be an assembly of tiny rods. Chemical and X-ray diffraction analyses suggested a carbonate-containing apatite as the most probable substance.

Adult↗
PubMed2000

Hyaluronan in synovial fluid of patients with loose total hip prosthesis. Comparison with hyaluronan in patients with hip osteoarthritis and idiopathic osteonecrosis of femoral head.

The concentration and molecular weight of hyaluronan (HA) in the synovial fluid of the hip joint were determined in 13 patients (aged 62.8 +/- 9.4 years) who had undergone prior total hip arthroplasty(THA), 23 patients (aged 65.0 +/- 8.2 years) with osteoarthritis of the hip joint (OA), and 13 patients (aged 40.2 +/- 2.7 years) with idiopathic osteonecrosis of the femoral head (ION). A sample of synovial fluid was obtained during revision THA because of loosening of the total hip prosthesis for the THA group, and during the first replacement surgery or osteotomy for the OA and ION groups. The concentration of HA in the synovial fluid was 0.64 +/- 0.42 mg/ml in the THA group, 1.07 +/- 0.28 mg/ml in the OA group, and 1.30 +/- 0.56 mg/ml in the ION group. The concentration of HA in the synovial fluid of the THA patients was significantly lower than that of the OA and ION patients (P = 0.0156 vs OA, P = 0.003 vs ION). The molecular weight of HA was 309 +/- 88.3 x 10(4) Da in the THA group, 377 +/- 201 x 10(4) Da in the OA group, and 240 +/- 148 x 10(4) Da in the ION group; these values do not differ significantly (P = 0.259 vs OA, P = 0.174 vs ION). Among the THA patients, there was no relation between the concentration of HA and the age of the patient, length of time since the first operation, or type of prosthesis fixation; there was also no relation between the molecular weight of HA and each of these factors. These results suggest that a pseudosynovial membrane is regenerated after THA, and that it produces HA of the same molecular weight as that in patients with OA and ION, although in smaller quantities.

Adult↗
PubMed2000

Does chondroitin sulfate defend the human uterine cervix against ripening in threatened premature labor?

OBJECTIVE: This study was undertaken to investigate changes in chondroitin sulfate levels in the cervix and the physiologic role of chondroitin sulfate isomers in the process of cervical ripening. STUDY DESIGN: Uterine cervical mucus samples were obtained from 57 women (7 nonpregnant women, 19 at preterm gestation, 9 at term gestation, 16 during the first stage of term labor, and 6 with threatened premature labor). Chondroitin sulfate isomer (chondroitin 0-sulfate, 4-sulfate, and 6-sulfate) concentrations in cervical mucus were measured by high-performance liquid chromatography. The effect of exogenous chondroitin sulfate on hyaluronidase activity in cervical mucus was evaluated by gel permeation chromatography of fluorolabeled hyaluronic acid. RESULTS: Chondroitin sulfate concentrations in cervical mucus were increased significantly (P <. 05) in the threatened premature labor group compared with the preterm and term groups. However, the same finding was not observed in the first stage of term labor. Exogenous chondroitin sulfate inhibited hyaluronidase activity in mucus. CONCLUSION: Chondroitin sulfate may defend against cervical ripening in threatened premature labor.

Cervical Ripening↗
PubMed2000

Analysis of liquid accumulated in the distended capsular bag in early postoperative capsular block syndrome.

PURPOSE: To analyze the transparent liquid between the posterior lens capsule and the posterior chamber intraocular lens (PC IOL) in early postoperative capsular block syndrome and discuss the mechanism of posterior capsule distention. SETTING: Department of Ophthalmology, Tokyo University School of Medicine, and Tokyo Research Institute, Seikagaku Corporation, Tokyo, Japan. METHODS: This study evaluated 3 cases of capsular block syndrome presenting with transparent liquid in the distended capsular bag 1 day after cataract surgery. The transparent liquid material between the posterior capsule and PC IOL was aspirated and analyzed using high-performance liquid chromatography (HPLC). Also, sodium hyaluronate was diluted using a dialyzer to determine whether the aqueous humor was drawn into the capsular bag by an osmotic gradient across the capsule. RESULTS: The elution time of the samples was almost the same as that of sodium hyaluronate 1.0% (Healon) The concentration of the samples ranged from 3.29 to 9. 01 mg/mL by HPLC analysis. The sodium hyaluronate absorbed the physiological salt solutions through the dialyzer and expanded to 1. 9 times its original volume. CONCLUSIONS: These results indicate that the main ingredient of the transparent liquid in capsular bags is sodium hyaluronate and that the distention is caused by aqueous humor being drawn into the capsular bag by an osmotic gradient across the capsule when the capsulorhexis diameter is smaller than that of the PC IOL and by viscoelastic material retained and trapped in the bag intraoperatively.

Aged↗
PubMed2000

Increased levels of serum interleukin-18 in Graves' disease.

We have previously reported that serum soluble interleukin-2 receptor (sIL-2R) and IL-12 levels were significantly increased in hyperthyroid Graves' disease. In this study, we investigated serum IL-18 levels in patients with either Graves' disease or Hashimoto's thyroiditis. The serum IL-18 levels in Graves' disease were significantly increased in the hyperthyroid state and were decreased during treatment with methimazole or propylthiouracil. On the other hand, the levels in Hashimoto's thyroiditis in the hypothyroid state showed no significant differences from those in healthy subjects. When liothyronine sodium was administered orally to healthy subjects, serum IL-18 levels were not changed. Positive correlations between serum IL-18 and IL-12, IL-12 and sIL-2R, and sIL-2R and IL-18 levels were noted in Graves' disease. These results suggest that Th1 cytokines might play an important regulatory role in Graves' disease.

Adolescent↗
PubMed2000

Estimating neural sources from each time-frequency component of magnetoencephalographic data.

We have developed a method that incorporates the time-frequency characteristics of neural sources into magnetoencephalographic (MEG) source estimation. This method, referred to as the time-frequency multiple-signal-classification algorithm, allows the locations of neural sources to be estimated from any time-frequency region of interest. In this paper, we formulate the method based on the most general form of the quadratic time-frequency representations. We then apply it to two kinds of nonstationary MEG data: gamma-band (frequency range between 30-100 Hz) auditory activity data and spontaneous MEG data. Our method successfully detected the gamma-band source slightly medial to the N1m source location. The method was able to selectively localize sources for alpha-rhythm bursts at different locations. It also detected the mu-rhythm source from the alpha-rhythm-dominant MEG data that was measured with the subject's eyes closed. The results of these applications validate the effectiveness of the time-frequency MUSIC algorithm for selectively localizing sources having different time-frequency signatures.

Acoustic Stimulation↗
PubMed2000

Studies on 8-methoxyquinolones: synthesis and antibacterial activity of 7-(3-amino-4-substituted)pyrrolidinyl derivatives.

A series of 8-methoxyquinolones bearing 3-amino-4-methylpyrrolidines or 3-amino-4-fluoromethylpyrrolidines at the C-7 position was synthesized and their physicochemical and biological properties were evaluated. All of the compounds synthesized showed more potent activity than LVFX (3) against both gram-positive and negative bacteria. Increases in lipophilicity of these compounds had desirable effects on their potency of single intravenous toxicity and pharmacokinetic profiles in animals. Among the compounds synthesized, 1-fluorocyclopropyl derivatives 17 and 20, and 7-(cis-3-amino-4-fluoromethylpyrrolidinyl) derivative 19 (DC-756h) showed negative responses in the micronucleus test in mice while 1-cyclopropyl-7-(3-aminopyrrolidinyl) derivative 16 showed a positive response. These results suggested that the introduction of a fluorine atom into the 3-aminopyrrolidinyl substituent resulted in favorable influence on genetic toxicity as well as into the N-1 cyclopropyl substituent.

Animals↗