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Biomedical subjects

T Miyabayashi

Publications and source records attributed to T Miyabayashi.

At least 19 recordsLinked to original sources
PubMed2003

Progressive changes in ophthalmic blood velocities in Beagles with primary open angle glaucoma.

OBJECTIVE: To measure changes in the ocular and orbital blood flow velocities by color Doppler imaging (CDI) in beagles with primary open angle glaucoma as the disease progressed from early to advanced stages. METHODS: CDI measurements were performed periodically on 13 glaucomatous Beagles during the nontreated mild, moderate and advanced stages of POAG over the course of 4 years. CDI was performed with the dogs lightly anesthetized (butorphanol 0.1 mg/kg IV, acepromazine maleate 0.02 mg/kg IV, and atropine sulfate 0.05 mg/kg) while the CD transducer was placed directly on the cornea anesthetized with 0.5% tetracaine hydrochloride. Intraocular pressure (IOP) by pneumatonography or TonoPen XL, heart rate and mean arterial blood pressure were measured at the beginning, middle and end of each study. The ophthalmic vessels examined included: external ophthalmic arteries and veins, long and short posterior ciliary arteries, anterior ciliary arteries and veins, primary retinal arteries, and vortex veins. Recordings of each vessel included peak systolic velocity (PSV), end diastolic velocity (EDV) and time averaged velocity (TAV), and when possible the resistive index (RI) and pulsatility index (PI) were computed. RESULTS: CDI abnormalities were present before intraocular pressure exceeded the normal range. As the animals aged, and the glaucoma progressed with higher levels of IOP, significant changes occurred in nearly all vessels, and generally included a major increase in RI (P < 0.001) and an increase in the PI (P < 0.001). Mean arterial blood pressure (105 +/- 18 mmHg) and heart rate (118 +/- 33/min) remained reasonably constant. The IOP gradually increased as the disease progressed (early and normotensive: 19.4 +/- 3.9 mmHg; moderate: 29.7 +/- 2 mmHg; and advanced: 44.5 +/- 6 mmHg). The ocular veins seemed most influenced early on in the disease. Late in the disease, ocular venous blood flow could not be consistently demonstrated. An increase in the PI of ocular veins occurred in the moderately and severely affected glaucomatous Beagles. As the IOP increased, there were trends of increasing resistive index and pulsatility index in most arteries, and periods of marked decreased velocities of the vortex and external ophthalmic veins in severe cases. CONCLUSION: CDI measurements in Beagles with primary open angle glaucoma during the course of 4 years indicate easily measurable and repeatable progressive blood flow abnormalities before the elevation of IOP and, thereafter, with gradually increased levels of IOP.

Animals↗
PubMed2001

Human homologues of Delta-1 and Delta-4 function as mitogenic regulators of primitive human hematopoietic cells.

Delta-mediated Notch signaling controls cell fate decisions during invertebrate and murine development. However, in the human, functional roles for Delta have yet to be described. This study reports the characterization of Delta-1 and Delta-4 in the human. Human Delta-4 was found to be expressed in a wide range of adult and fetal tissues, including sites of hematopoiesis. Subsets of immature hematopoietic cells, along with stromal and endothelial cells that support hematopoiesis, were shown to express Notch and both Delta-1 and Delta-4. Soluble forms of human Delta-1 (h Delta-1) and h Delta-4 proteins were able to augment the proliferation of primitive human hematopoietic progenitors in vitro. Intravenous transplantation of treated cultures into immune-deficient mice revealed that h Delta-1 is capable of expanding pluripotent human hematopoietic repopulating cells detected in vivo. This study provides the first evidence for a role of Delta ligands as a mitogenic regulator of primitive hematopoietic cells in the human. (Blood. 2001;97:1960-1967)

Adaptor Proteins, Signal Transducing↗
PubMed2001

A novel Fc receptor for IgA and IgM is expressed on both hematopoietic and non-hematopoietic tissues.

By contrast to well-defined Fc gamma and Fc epsilon receptors, the structural and functional characteristics of Fc mu receptor are unclear. We have recently described a novel mouse Fc receptor, designated Fc alpha/mu receptor, and its human homologue, which bind both IgM and IgA. Here we show that the Fc alpha/mu receptor is expressed on mature, but not immature, B lymphocytes and acquires the ability to bind IgM and IgA antibodies after stimulation of B lymphocytes. Moreover, stimulation with phorbol 12-myristate 13-acetate increased endocytosis of IgM-coated microparticles mediated by the Fc alpha/mu receptor expressed on pro-B cell line Ba/F3 cells. We also show that the Fc alpha/mu receptor is expressed in secondary lymphoid organs, such as lymph node and appendix, kidney and intestine, suggesting an important role of the receptor for immunity in these organs.

Animals↗
PubMed2001

Quantitative analysis of chondroitin sulfate isomers in intervertebral disk chondrocyte culture using capillary electrophoresis.

Chondroitin sulfate (CS) isomers, 6-sulfate (CS6) and 4-sulfate (CS4), change their ratio to each other in cartilaginous tissues with aging. In this study, a quantitative measurement method of CS6 and CS4 was developed, using capillary electrophoresis (CE). Various buffer solutions, pH, and digestion times were studied, and the use of 0.1 M Tris-HCl at pH of 8.0 allowed the isolation of CS6 and CS4 from CS most efficiently when combined with chondrotinase ABC at a concentration of 1 mU/microg of the substrate during a 3 hr digestion period. Amounts of newly synthesized CS6 and CS4 in the intervertebral disk chondrocyte three-dimensional culture were quantified by this method after the proteoglycans were extracted by equilibrium density centrifugation.

Animals↗
PubMed2000

Fc alpha/mu receptor mediates endocytosis of IgM-coated microbes.

IgM is the first antibody to be produced in a humoral immune response and plays an important role in the primary stages of immunity. Here we describe a mouse Fc receptor, designated Fc alpha/microR, and its human homolog, that bind both IgM and IgA with intermediate or high affinity. Fc alpha/microR is constitutively expressed on the majority of B lymphocytes and macrophages. Cross-linking Fc alpha/microR expressed on a pro-B cell line Ba/F3 transfectant with soluble IgM or IgM-coated microparticles induced internalization of the receptor. Fc alpha/microR also mediated primary B lymphocyte endocytosis of IgM-coated Staphylococcus aureus. Thus, Fc alpha/microR is involved in the primary stages of the immune response to microbes.

Amino Acid Sequence↗
PubMed2000

[A Japanese language version of the health-promoting lifestyle profile].

The development and initial psychometric evaluation of a Japanese version of the Health-Promoting Lifestyle Profile II (HPLP II) is described. The 52-item instrument was translated into Japanese and was found to be culturally relevant and reliable in a pilot study. The Japanese version was then administered to adiverse but predominantly Japanese group of 337 subjects residing in northern Japan. The Japanese version of the HPLP II was evaluated using factor analysis and reliability measurement. Six factors similar to those isolated previously during psychometric assessment of the English language version were extracted. Those six dimensions comprise the HPLP II subscales of: 1. Health responsibility, 2. Spiritual growth, 3. Physical activity, 4. Interpersonal relations, 5. Nutrition, and 6. Stress management. The alpha reliability coefficient for the total scale was 0.94 and the 2-week retest reliability was 0.91; the alpha coefficients for the subscales ranged from 0.70 to 0.87. The Japanese language version of the HPLP II appears to have sufficient validity and reliability for use by researchers who wish to describe the health-promoting components of lifestyle among the Japanese population and to explore differences and similarities in the health-promoting lifestyle of Japanese and American subjects or those of other ethnic groups. Further evaluations of measurement with different populations appears warranted. This instrument will enable researchers to investigate patterns and determinants of health-promoting lifestyle, as well as the effects of interventions to alter the lifestyle.

Health Promotion↗
PubMed1999

Expression and function of members of a divergent nuclear receptor family in Caenorhabditis elegans.

Nuclear receptors (NRs) are a large class of ligand-regulated transcriptional modulators that have been shown to play roles in many developmental processes. The Caenorhabditis elegans genome is predicted to encode a large and divergent family of NR proteins. The functions of most of these genes are unknown. As a first step toward defining their roles, we have initiated an expression and functional survey of a subset of these genes. In this study, we demonstrate expression of 21 of 28 NR genes examined, indicating that a large fraction of the predicted genes likely encode functional gene products. We show that five genes are expressed predominantly in neuronal cells, while others are expressed in multiple cell types. Interestingly, we find that eight genes are expressed exclusively in the lateral hypodermal (seam) cells. These eight genes share a high degree of overall homology and cluster in a neighbor-joining tree derived from sequence analysis of the NRs, suggesting that they arose by gene duplication from a common ancestor. We show that overexpression of each of three members of this subfamily results in similar developmental defects, consistent with a redundant role for these genes in the function of the lateral hypodermal cells.

Animals↗
PubMed1998

Cloning and expressions of three mammalian homologues of Drosophila slit suggest possible roles for Slit in the formation and maintenance of the nervous system.

In Drosophila embryogenesis, the slit gene has been shown to play a critical role in CNS midline formation. However, no slit homologues have been reported in vertebrates. Here, we have identified mammalian homologues of the slit gene (human Slit-1, Slit-2, Slit-3, and rat Slit-1). Each Slit gene encodes a putative secreted protein, which contains conserved protein-protein interaction domains including leucine-rich repeats (LRR) and epidermal growth factor (EGF)-like motifs, like that of the Drosophila protein. Northern blot analysis revealed that the human Slit-1, -2, and -3 mRNAs are exclusively expressed in the brain, spinal cord, and thyroid, respectively. In situ hybridization studies indicated that the rat Slit-1 mRNA is specifically expressed in the neurons of fetal and adult forebrains. Our data suggest that Slit genes form an evolutionary conserved group in vertebrates and invertebrates, and that the mammalian Slit proteins may participate in the formation and maintenance of the nervous and endocrine systems by protein-protein interactions.

Amino Acid Sequence↗
PubMed1998

The contrecoup injury in a cat case of traffic accident: MRI findings.

The clinical application of MRI of a cat case of traffic accident was examined. On admission, the animal was unconscious and remained so for 2 days. Radiographs disclosed a fracture in the parietal bone. From the temporary unconscious status and the fracture, cerebral damage was suspected and an MRI examination was performed. The contrecoup injury in the cat case of traffic accident which could not be diagnosed by radiography was diagnosed by MRI examination.

Accidents, Traffic↗
PubMed1996

Quantitation of a new potent angiotensin II receptor antagonist, TCV-116, and its metabolites in human serum and urine.

A sensitive high-performance liquid chromatographic (HPLC) method is described for the determination of a new potent antihypertensive agent, TCV-116, and its two metabolites (M-I and M-II) in human serum or urine. After pre-treatment of the specimens, the analytes were determined using a column switching technique, except for the metabolites in urine which were determined by gradient elution mode HPLC. The quantitation limits for TCV-116, M-I and M-II were all 0.5 ng/ml in serum, and 0.5, 10 and 110 ng/ml in urine, respectively. The methods were applied to clinical trials of TCV-116.

Angiotensin II↗
PubMed1995

Development and validation of column-switching high-performance liquid chromatographic methods for the determination of a potent AII receptor antagonist, TCV-116, and its metabolites in human serum and urine.

Column-switching HPLC methods have been developed and validated for the determination of a new antihypertensive prodrug, TCV-116 (I), and its metabolites, CV-11974 (II) and CV-15959 (III), in human serum and urine. Initial sample cleanup was achieved by extracting the analytes into an organic solvent. After chromatographing on an ODS column with a mobile phase consisting of acetonitrile and an acidic phosphate buffer, the zone of the analyte's retention was heart-cut onto a second ODS column with a mobile phase of acetonitrile and a phosphate buffer at a higher pH. Complete separation of the analytes and the endogenous peaks was accomplished by the two-dimensional chromatography. Good precision and linearity of the calibration standards, as well as the inter-day and intra-day precision and accuracy of quality control samples, were achieved. The limit of quantitation (LOQ), using 0.5 ml of serum, was 2 ng/ml for I, 0.8 ng/ml for II, and 0.5 ng/ml for III. The LOQ for urine sample was 10 ng/ml for II and III. Stability of the analytes during storage, extraction, and chromatography processes was established. The results illustrate the versatile application of column switching to method development of multiple analytes in various biological matrices. The methods have been successfully used for the analyses of I and its metabolites in thousands of clinical samples to provide pharmacokinetic data.

Angiotensin II↗
PubMed1994

Ultrasonographic diagnosis of pyelonephritis in a cow.

A 2-year-old Holstein cow was examined because of a 2-month history of anorexia, decreased milk production, and a white vaginal discharge. Results of physical, laboratory, and ultrasound examinations were consistent with pyelonephritis. Through ultrasound examination, the right kidney and ureter were identified as structurally involved. Right nephrectomy was performed. Eight months after nephrectomy, the cow was clinically normal. In this cow, ultrasonography helped to determine disease severity, to direct the course of treatment, and to improve the accuracy of diagnosis and prognosis.

Animals↗
PubMed1994

Scintigraphic and ultrasonographic diagnosis of soft tissue injury in a thoroughbred horse.

A 2.5-year-old female Thoroughbred horse was referred to the veterinary teaching hospital for right front limb lameness of 1 year duration. Physical examination and diagnostic nerve blocks failed to localize the origin of the lameness. Scintigraphy with 99mTc-MDP suggested increased radionuclide uptake in the palmar metacarpal soft tissues of the right front limb. Ultrasonographic examination revealed hypoechoic lesions in the superficial digital flexor tendon and the suspensory ligament, suggesting tendinitis and desmitis. Combined imaging modalities improved detection and characterization of the cause of a long-standing obscure lameness.

Animals↗
PubMed1993

Complications after ultrasound-guided biopsy of abdominal structures in dogs and cats: 246 cases (1984-1991).

Medical records of 195 dogs and 51 cats that underwent a total of 233 ultrasound-guided biopsies and 70 ultrasound-guided fine-needle aspirations were reviewed for diagnostic quality of the specimens obtained and for procedural complications. Three animals (1.2%) had major postbiopsy complications. All 233 animals that underwent ultrasound-guided biopsy were examined ultrasonographically immediately after biopsy. Thirteen (5.6%) were determined to have minor localized hemorrhage. Of the 233 biopsy specimens, 226 (97%) were considered to be of adequate quality for histologic interpretation. Results of cytologic examination of 59 (84.3%) of 70 specimens obtained by fine-needle aspiration correlated with the final diagnosis made during surgical exploration or at necropsy.

Animals↗
PubMed1993

Use of iohexol as a gastrointestinal contrast agent in three dogs, five cats, and one bird.

Barium sulfate suspension is routinely used as contrast medium for upper gastrointestinal procedures. It has been contraindicated for use in cases of suspected perforation. In such instances, water-soluble iodides are recommended for use. Most of the water-soluble iodides available for use in veterinary medicine at this time are hyperosmolar. This results in in transit dilution of the contrast column. The dilution of the contrast agent within the intestines may prevent visualization of a perforation, especially if the perforation is in the distal portion of the small intestine. Iohexol a nonionic water-soluble iodide of low osmolality, is currently used in veterinary medicine for myelography. We have used it as the contrast agent for upper gastrointestinal studies in cases of suspected obstruction or perforation, with good results, and no adverse effects have been associated with its use. Opacity of the contrast column was adequate, and segmentation or flocculation of the column was not apparent.

Animals↗