Search PubMed⌕ Search

Biomedical subjects

K Hayashi

Publications and source records attributed to K Hayashi.

At least 325 records · Page 18Linked to original sources
PubMed2000

Identification of a novel 23kDa protein encoded by putative open reading frame 2 of TT virus (TTV) genotype 1 different from the other genotypes.

We report the entire open reading frames (ORFs) sequences of four TT virus (TTV) isolates, one genotype 2 (G2) and three G4 isolates. Despite a DNA virus, TTV possesses high rate of amino acid (aa) substitution: the aa sequence homology of ORF1 and 2 is lower than the nucleotide homology. The partial 'N22' region of ORF1 is suitable for genotyping of 'prototype TTV' isolates, because the phylogenetic tree from partial 'N22' sequence is consistent with that from the entire ORF1. Based on our sequence data, ORF2 from most isolates excluding G1 encode truncated 49 aa (pORF2a) because of an in-frame stop codon, although ORF2s from most G1 isolates encode 202 aa (pORF2ab). Just downstream the stop codon, another ORF encoding a protein of approximately 150 aa (pORF2b) is found, whose homology is quite low among these genotypes. Our in vitro transcription/translation study supports that all G1a and a part of G b without an in-frame stop codon dominantly encode pORF2ab, a novel 23 kDa protein, whereas the other genotypes with an in-frame stop codon encode pORF2b (17 kDa). Our data indicate TTV G1a and a part of G1b should have different characteristics from the other genotypes.

Amino Acid Sequence↗
PubMed2000

Types of synovial fold in the cervical facet joint.

Few detailed studies of synovial folds of cervical facet joints exist at the moment. This study was performed to provide anatomical data for each synovial fold in the cervical facet joints, using 20 cervical spines from C2 to C7 for dissection. Anatomic evaluation of the synovial folds included the gross morphology, in three dimensions, and the histology. Also, degenerative changes of the lower facet surface on which synovial folds occurred were evaluated. On the basis of gross morphology and histological composition, three types of synovial folds were identified. Type-1 synovial folds, shaped like a crescent, consisted principally of adipose tissue. Type-2 synovial folds had an apical region made up of dense fibrous tissue, with the base and middle region consisting of adipose tissue. In type-2 folds, the size and shape varied, including some elliptic-shaped synovial folds projecting well into the joint cavity. Type-3 synovial folds were thin with ragged free borders, and were formed exclusively of fibrous tissue. This study shows the variable appearance of synovial folds. Speculation was raised that the articular facet impingement of a large synovial fold and the subluxation of a smaller structure may play a possible role in the pathology of some disorders of the neck.

Adult↗
PubMed2000

Influence of astigmatism on multifocal and monofocal intraocular lenses.

PURPOSE: To examine the influence of astigmatism on the visual acuity of patients with multifocal and monofocal intraocular lenses. METHODS: Thirty eyes of 30 patients who underwent five-zone refractive multifocal intraocular lens implantation and 30 eyes of 30 age-matched patients who had monofocal intraocular lens implantation were included. The visual acuities of these patients at 5.0, 3.0, 2.0, 1.0, 0.7, 0.5, and 0.3 m were measured by means of an all-distance vision tester after addition of a cylindrical lens of 0, 0.5, 1.0, 1.5, 2.0, and 2.5 diopters. RESULTS: Mean visual acuity at all distances decreased in proportion to the diopters of astigmatism in both the multifocal and monofocal intraocular lens groups. When astigmatism was 0.5, 1.0, or 1.5 diopters, distance visual acuity in the multifocal group was significantly worse than that in the monofocal group; with astigmatism of 2.0 diopters or more, intermediate visual acuity was also worse in the multifocal group. In contrast, near visual acuity in the multifocal group was significantly better than that in the monofocal group at all astigmatic diopters. When astigmatism was within 1.0 diopter, visual acuity in the multifocal group reached 20/29 at distance and 20/50 at near. Mean contrast sensitivity was also worse in the multifocal group than in the monofocal group. CONCLUSIONS: Both distance and intermediate visual acuity deterioration caused by astigmatism was greater with a multifocal intraocular lens than with a monofocal intraocular lens, whereas near visual acuity was better with the multifocal intraocular lens. When astigmatism was within 1.0 diopter, eyes with a multifocal intraocular lens achieved good visual acuity at both distance and near.

Accommodation, Ocular↗
PubMed2000

A newly designed tensile tester for cells and its application to fibroblasts.

A tensile test system for cells has been designed and applied to fibroblasts from the rabbit patellar tendon. It consists of a thermostatic test chamber, an inverted fluorescence microscope, micromanipulators, a direct drive linear actuator, a cantilever-type load cell, and a video dimension analyzer (VDA). The test chamber and the microscope are mounted on a vibration isolator. A cell floated in Hanks' balanced salt solution of 37 degrees C is gripped with a pair of micropipettes which have very fine tips (outer diameter = 20 approximately 30 microm, inner diameter = 3 approximately 5 microm) and are coated with a cell adhesive, Cell-Tak, at their ends. One of the micropipettes is fixed to the load cell; the other one is attached to the linear actuator which is used to stretch the cell. Load applied to the cell is measured with the load cell, while elongation of the cell is determined with the VDA using the images of the ends of the micropipettes as markers. The measurement accuracy of the load cell was +/-0.05 microN. All the fibroblasts tested were firmly attached to the micropipettes during tensile testing, and showed local non-uniform deformation. The maximum load and elongation to failure of the cells were 0.9+/-0.2 microN and 86+/-24 microm, respectively.

Animals↗
PubMed2000

Measurements of 1,2-diacylglycerol and ceramide in hearts subjected to ischemic preconditioning.

An accumulation of recent evidence suggests that the mechanism in ischemic preconditioning (IPC) may involve the activation of protein kinase C (PKC) regulatory pathway. In this study, we examined whether the content of 1,2-diacylglycerol (1,2-DAG) and ceramide, which are intracellular second messengers regulating PKC activity, change during IPC in isolated perfused rat hearts, and whether the observed change in 1,2-DAG is accompanied with alteration in its fatty acid composition. Hearts subjected to IPC, consisting of 5-min transient global ischemia followed by 5-min reperfusion, presented a significant functional recovery during subsequent 40-min reperfusion following 40-min global ischemia compared with non-preconditioned hearts. An increase in 1,2-DAG content was observed in hearts subjected to 5-min transient ischemia compared with non-ischemic control hearts, however this was not seen in hearts harvested after 5-min reperfusion following 5-min ischemia. While fatty acid composition in 1,2-DAG was virtually unchanged in hearts subjected to 5-min ischemia, saturated 1,2-DAG decreased and monounsaturated/polyunsaturated 1,2-DAG increased in hearts reperfused for 5-min following 5-min ischemia compared with the non-ischemic control hearts. Ceramide mass did not change significantly, suggesting that the contribution of ceramide may be small in IPC. These data are in concert with the hypothesis that 1,2-DAG is a second messenger in IPC and the changes in fatty acid composition of 1,2-DAG may add new insight concerning signal transduction pathway in IPC.

Animals↗
PubMed2000

Gibbestatin B inhibits the GA-induced expression of alpha-amylase expression in cereal seeds.

The expression of alpha-amylase in aleurone layers of barley is known to be induced by gibberellin A3 (GA). In the present study, gibbestatin B (GNB) was isolated from Streptomyces sp. C-39 as an inhibitor of the GA-induced expression of alpha-amylase in barley and rice, with IC50 values of 125 and 70 microM, respectively. GNB suppressed accumulation of GA-induced barley high-pI type B and rice RAmylA alpha-amylase transcripts. However, GNB showed no inhibitory activity on GUS expression in transgenic tobacco harboring the auxin-inducible par B promoter:: GUS fusion gene. The transcription of an abscisic acid (ABA)-inducible gene, HVA1, was unaffected by GNB. In addition, GNB prevented aleurone cells from cell death induced by GA. In tobacco and Arabidopsis plants, GNB suppressed the germination and retarded the growth of seedlings without toxicity. The growth of gai, spy and abi mutants was also retarded by GNB. Normal plants treated with GA-biosynthesis inhibitors and GA-defective and GA-signaling mutants normally have dwarf dark green leaves. However, dwarfed healthy green leaves were observed in normal plants treated with GNB. GA-induced stem elongation of plants was also detected in the presence of GNB. These analyses indicate that GNB inhibits the GA-induced expression of alpha-amylase by regulating one of the steps involved in ABA signaling, but not by acting as a weak ABA analog.

Abscisic Acid↗
PubMed2000

Skull metastasis of hepatocellular carcinoma associated with acute epidural hematoma: a case report.

BACKGROUND: Although epidural hematoma is well documented in trauma patients, its association with other etiologies, such as neoplasms, is not widely known. Here the authors report a case of acute epidural hematoma that originated from a metastatic hepatocellular carcinoma (HCC) in the skull. CASE DESCRIPTION: A 70-year-old male was admitted to our hospital with left-sided hemiparesis. Preoperative computed tomography (CT) revealed a lenticular high-density area adjacent to the right parietal bone, consistent with an acute epidural hematoma. A subsequent magnetic resonance image (MRI) showed a skull tumor adjacent to the epidural hematoma. Removal of the tumor and evacuation of the hematoma were performed and the pathological diagnosis was metastatic HCC. Postoperatively, the patient gradually recovered but he died of pneumonia 2 months later. CONCLUSION: This report represents an additional example of a rare case of metastatic skull tumor associated with acute epidural hematoma. The authors suggest that metastatic skull tumors may be one of the important differential diagnoses in patients with acute epidural hematoma.

Acute Disease↗
PubMed2000

Changes in anterior chamber angle width and depth after intraocular lens implantation in eyes with glaucoma.

OBJECTIVE: To examine the changes in anterior chamber angle width and depth induced by intraocular lens (IOL) implantation in eyes with angle-closure glaucoma (ACG), in eyes with open-angle glaucoma (OAG), and in eyes with no evidence of glaucoma or ocular hypertension. DESIGN: A comparative, nonrandomized, interventional study. PARTICIPANTS: Seventy-seven eyes with ACG, 73 eyes with OAG, and 74 control eyes undergoing cataract extraction and IOL implantation. INTERVENTION: All eyes underwent phacoemulsification and soft acrylic IOL implantation. MAIN OUTCOME MEASURES: The angle width and depth of the anterior chamber were measured using a Scheimpflug videophotography system before surgery, and at 1 week and at 1, 3, 6, 9, and 12 months after surgery. RESULTS: Before surgery, the mean anterior chamber angle width and depth in the ACG group was less than that in either the OAG or control groups by approximately 10 degrees in angle width and 1.0 mm in depth (P < 0.0001). After cataract extraction and IOL implantation, the angle width and depth increased significantly in all three groups (P < 0.0001). Although the width and depth in the ACG group were still smaller than that in the other groups, the differences decreased to 2 degrees for angle width and 0.3 mm for depth. In addition, no significant differences were found in these values between the OAG and control groups before or after surgery. Furthermore, no significant changes were observed in the angle width or depth in any of the three groups throughout the postoperative observation period. As expected, the mean preoperative intraocular pressure (IOP) in the ACG and OAG groups was higher than that in the control group. After cataract surgery, however, the mean IOP decreased significantly and was almost the same in all three groups at 1, 6, and 12 months after surgery. CONCLUSIONS: The width and depth of the anterior chamber angle in eyes with ACG increased significantly after cataract extraction and IOL implantation and became similar to that in eyes with OAG and that in normal eyes, which may lead to the decrease in IOP seen in the postoperative period. No significant changes were observed in angle width and depth in any of the three groups after surgery.

Aged↗
PubMed2000

Non-muscle myosin IIB-like immunoreactivity is present at the drebrin-binding cytoskeleton in neurons.

Dendritic spines are extremely motile, providing a structural mechanism for synaptic plasticity. Actin-myosin interaction is thought to be responsible for the change in the shape of spine. We have already reported that drebrin, an actin-binding protein, inhibits actin-myosin interaction and is enriched in the dendritic spine of mature neurons. In this study, we prepared the actin cytoskeleton of dendritic spines as an immunoprecipitate with anti-drebrin antibody from adult guinea-pig brain, immunized mice with the cytoskeleton, and obtained a monoclonal antibody (MAb) called MAb G650. MAb G650 reacted with non-muscle myosin IIB, but it did not react with muscle myosin II or non-muscle myosin IIA. Immunoblotting with this antibody revealed that drebrin-binding cytoskeleton contains this myosin IIB-like immunreactivity. Immunohistochemistry using MAb G650 demonstrated that this myosin IIB-like immunreactivity can be detected in the neuronal cell bodies and their apical dendrites, where drebrin is hardly detected. These data demonstrate that a myosin subtype associated with drebrin-binding actin filaments in the dendritic spines is myosin IIB, although this myosin is widely distributed in somato-dendritic subdomains of neurons. Furthermore, it is indicated that the cytoskeletons in dendritic spine were uniquely characterized with actin-binding proteins such as drebrin, but not with myosins.

Animals↗
PubMed2000

A case of chronic hepatitis C developing insulin-dependent diabetes mellitus associated with various autoantibodies during interferon therapy.

We report a case of chronic hepatitis C presenting insulin-dependent diabetes mellitus (IDDM) associated with various autoantibodies including possible anti-insulin receptor antibody (AIRA) during interferon (IFN) therapy. A 57-year-old man having chronic hepatitis C virus (HCV) infection with chronic thyroiditis received IFN therapy. The thyroid function was well-controlled by administration of thyroid hormone, although thyroid autoantibodies were positive. At 15 weeks after starting IFN (reaching 530 million units of total dose), marked thirst happened, with increased fasting plasma glucose level (488 mg/dl) and decreased daily urinary C peptide immunoreactivity level (less than 4.2 microg/day). IDDM occurred with anti-nuclear antibody (ANA), anti-DNA antibody and possible AIRA, and thyroid autoantibodies titers increased, but without pancreatic islet cell antibody and anti-glutamic acid decarboxylase antibody. Administration of IFN was stopped and insulin treatment was started, but plasma glucose level was not controlled well. AIRA became negative 2 months later, however, insulin antibody (IA) was positive when tested after 18 months. Serum HCV RNA has been negative, and a normal level of serum transaminase has been observed since IFN therapy. It is likely that IFN therapy induced the immunological disturbance and resulted in occurrence of various autoantibodies and IDDM in the patient.

Antibodies, Antinuclear↗
PubMed2000

Mechanical properties of collagen fascicles from in situ frozen and stress-shielded rabbit patellar tendons.

OBJECTIVE: To know the effects of stress shielding on the biomechanical properties of collagen fascicles obtained from in situ frozen patellar tendons (an autograft model). DESIGN: Collagen fascicles of approximately 300 microm in diameter were obtained from in situ frozen rabbit patellar tendons and also from in situ frozen and stress-shielded ones, and their mechanical properties and fibroblast density were determined. BACKGROUND: Stress shielding changes the mechanical properties of in situ frozen patellar tendons in which there exist no fibroblasts. The mechanisms of this phenomenon have not been studied well. METHOD: Patellar tendons of both in situ frozen group and in situ frozen and stress-shielded group were frozen in situ by liquid nitrogen to kill fibroblasts. Then, in the in situ frozen and stress-shielded group, no tension was applied to the tendons for 2, 3, and 6 weeks, while normal tension was applied to the tendons of the in situ frozen group. Tensile properties of the collagen fascicles obtained from these tendons were determined using a microtensile tester, and were compared to the collagen fascicles from non-frozen, stress-shielded patellar tendons. RESULTS: Tangent modulus and tensile strength of collagen fascicles from the in situ frozen and stress-shielded group progressively decreased with the time of stress shielding; however, these decreases were much smaller than those of the fascicles obtained from non-frozen, stress-shielded tendons. Although there were few fibroblasts in the patellar tendon of the in situ frozen and stress-shielded group at 2 weeks, the modulus and strength of the fascicles from the posterior portion were significantly lower than those in the in situ frozen group. In addition, the reduction of strength caused by stress shielding was much smaller in collagen fascicles than in bulk patellar tendons. CONCLUSION: The mechanical properties of collagen fascicles in in situ frozen tendons (an autograft model) are affected by stress shielding even under acellular condition. RelevanceThe in situ frozen, stress-shielded patellar tendon is a model of augmented autografts which are clinically used for the reconstruction of injured anterior cruciate ligaments. The sub-macroscopic studies of the tendon are useful to understand the mechanisms of the reduction of graft strength and its gradual recovery observed after reconstruction.

Animals↗
PubMed2000

Effects of growth on the response of the rabbit patellar tendon to stress shielding: a biomechanical study.

OBJECTIVE: To know the effect of stress deprivation on the dimensions and mechanical properties of the patellar tendon during growth. DESIGN: The dimensions and tensile properties of stress-shielded patellar tendons were studied in growing rabbits and compared to those in mature animals. BACKGROUND: Although the effects of stress deprivation on the remodeling of ligaments and tendons have been studied in various animal models, the effect of growth on the remodeling has not been studied well. METHOD: A stress shielding technique was applied to 1-, 2-, and 3-month-old Japanese white rabbits to completely remove stress in the patellar tendons for 4, 7, and 14 days. Changes in the dimensions and mechanical properties as well as fibroblast density of the tendon were determined. RESULTS: The tensile strength and tangent modulus of the patellar tendons were markedly decreased by stress shielding, while the cross-sectional area was significantly increased, with the largest changes in 1-month-old rabbits. Fibroblast density also increased; however, the degree of increase was highest in 3-month-old rabbits. CONCLUSION: The changes in the dimensions and mechanical properties of the patellar tendons induced by stress shielding were greater in younger animals. RELEVANCE: The biomechanical response of tendons and ligaments to stress deprivation induced by, for example, limb immobilization is greater and occurs earlier in younger subjects, which is important for the surgical treatment and rehabilitation protocol of joint diseases in young subjects.

Age Factors↗
PubMed2000

cDNA cloning and sequencing of phospholipase A2 from the pyloric ceca of the starfish Asterina pectinifera.

Three cDNA from the pyloric ceca of the starfish Asterina pectinifera, (namely, cDNA 1, 2, and 3), encoding phospholipase A2 (PLA2), were isolated and sequenced. These cDNAs were composed of 415 bp with an open reading frame of 414 bp at nucleotide positions 1-414, which encodes 138 amino acids including N-terminal Met derived from the PCR primer. The amino acid sequence deduced from the cDNA 1 was completely consistent with the sequence determined with the starfish PLA2 protein, while those deduced from cDNA 2 and cDNA 3 differed at one and twelve amino acid residual positions, respectively, from the sequence of the PLA2 protein, suggesting the presence of multiple forms in the starfish PLA2. All of the sequences deduced from cDNA 1, 2, and 3 required two amino acid deletions in pancreatic loop region, and sixteen insertions and three deletions in beta-wing region when aligned with the sequence of mammalian pancreatic PLA2. In phylogenetic tree, the starfish PLA2 should be classified into an independent group, but hardly to the established groups IA and IB. The characteristic structure in the pancreatic loop and beta-wing regions may account for the specific properties of the starfish PLA2, e.g. the higher activity and characteristic substrate specificity compared with commercially available PLA2 from porcine pancreas.

Amino Acid Sequence↗
PubMed2000

Carbon dioxide laser vaporization for turbinate: optimal conditions and indications.

UNLABELLED: Carbon dioxide (CO2) laser vaporization for turbinate has rapidly gained acceptance in Japan for the treatment of allergic rhinitis. OBJECTIVE: The aim of this study was to examine the effects of laser output, patient age, and the presence of a deviated nasal septum on treatment outcome in patients with intractable allergic rhinitis. METHODS: The inferior turbinates were irradiated at an output of 3 or 5 W for 0.1 s. RESULTS: Of 67 patients, 43 (64.2%) were judged to have symptoms which improved markedly or moderately after a single treatment. Treatment was more effective with a laser output of 5 W than with an output of 3 W. However, treatment was judged less effective in patients aged 15 years or less than in older patients. The presence of a slightly deviated nasal septum had no effect on treatment outcome. CONCLUSION: Although assessing outcome on the basis of symptoms is difficult, we believe that these findings will suggest the optimal conditions and indications for laser surgery for allergic rhinitis.

Adolescent↗
PubMed2000

Involvement of angiotensin II and endothelin-1 in the development of submandibular gland hypertrophy in response to isoproterenol in rats.

We investigated whether angiotensin II (Ang II) and endothelin-1(ET-1) are involved in submandibular hypertrophy in response to repeated treatment with isoproterenol (ISO) in rats. The immunoreactive Ang II (IRAng II) and immunoreactive ET-1 (IRET-1) contents of ISO-induced hypertrophy were significantly higher than those of control glands. Treatment of isolated gland tissues with ISO (1 microM) or dobutamine (1 microM) caused significant increases in the IRAng II and IRET- 1 contents of the glands compared with controls. These increases were suppressed by pretreatment with enalapril (3 microM) or captopril (3 microM). Treatment with Ang II (10 microM) also caused an increase in IRET-1 content. Our findings suggest that Ang II and ET-1 are involved in the submandibular gland hypertrophy that develops in rats repeatedly treated with ISO, and that these biologically active peptides may act as growth factors. They also imply that the tissue renin-angiotensin system and Ang II specific receptors are present in the submandibular glands.

Adrenergic beta-Agonists↗
PubMed2000

Fourier analysis of irregular astigmatism after implantation of 3 types of intraocular lenses.

PURPOSE: To evaluate irregular astigmatism after silicone, acrylic, and poly(methyl methacrylate) (PMMA) intraocular lens (IOL) implantation using Fourier analysis of videokeratography data. METHODS: Two hundred forty eyes having phacoemulsification and IOL implantation were randomly assigned to 1 of 3 groups: 3.5 mm incision and silicone IOL, 4.1 mm incision and acrylic IOL, or 6.5 mm incision and PMMA IOL. All eyes had videokeratographic examinations preoperatively and 2, 4, and 10 days and 1 and 3 months postoperatively. The dioptric data of the central cornea were decomposed into spherical equivalent, regular astigmatism, and irregular astigmatism (decentration and higher-order irregularity) components using Fourier analysis. RESULTS: Regular astigmatism in the PMMA group was greater than in the silicone and acrylic groups. Decentration in all 3 groups increased significantly postoperatively but virtually returned to preoperative levels by 10 days. No significant difference was observed among the 3 groups. Higher-order irregularity significantly increased after surgery in all 3 groups. The higher-order irregularity in the PMMA group persisted for up to 1 month, while that in the silicone and acrylic groups returned to preoperative levels by 4 days, resulting in significant differences between these groups 10 days and 1 month after IOL implantation. CONCLUSION: Irregular astigmatism, both the decentration and higher-order irregularity components, increased significantly after 3 types of scleral tunnel incisions for silicone, acrylic, or PMMA IOL implantation but returned to preoperative levels soon after surgery except for the higher order irregularity after PMMA IOL implantation.

Acrylic Resins↗