Biomedical subjects

Y Ide

Publications and source records attributed to Y Ide.

At least 37 records · Page 2Linked to original sources

PubMed1999

PEG-rHuMGDF ameliorates thrombocytopenia in carboplatin-treated rats without inducing myelofibrosis.

We examined the effects of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) on carboplatin-induced thrombocytopenia in rats. The focus was on whether myelofibrosis is associated with the PEG-rHuMGDF treatment in this chemotherapy model. After a single injection of carboplatin, rats received subcutaneous PEG-rHuMGDF at pharmacologic doses (1,3, or 30 micrograms/kg) or a vehicle daily for 7 days. PEG-rHuMGDF at more than 3 micrograms/kg ameliorated the thrombocytopenia at day 10. Histologically, no myelofibrosis was detected in the rats treated with PEG-rHuMGDF or vehicle. Subsequently, PEG-rHuMGDF at a suprapharmacologic dose (100 micrograms/kg) was subcutaneously administered to normal and to carboplatin-treated rats daily for 7 days. Histological analysis revealed that the treatment with PEG-rHuMGDF induced myelofibrosis in the normal rats but not in the carboplatin-treated rats. Additionally, the transforming growth factor-beta 1 (TGF-beta 1) levels in the extracellular fluid and the whole extract of the bone marrow were increased to a much lesser degree in the carboplatin-treated rats compared to the normal rats. These findings suggest that PEG-rHuMGDF is effective for carboplatin-induced thrombocytopenia. Proper control of platelet counts and TGF-beta 1 levels is essential so that myelofibrosis is not induced in clinical use.

Animals↗

PubMed1998

Pathological study of splenomegaly associated with cadmium-induced anemia in rats.

Splenomegaly was observed both in male and female Sprague-Dawley rats after 1 week of exposure to CdCl2 (0.6 mg Cd/kg/day). Spleen weight reached about double that in controls by 8 weeks of Cd exposure. Histopathological examination of the enlarged spleen revealed that iron- and lipid-laden histiocytes were clustered in the periarterial lymphatic sheath, and the red pulp appeared to be expanded. It is noteworthy that electron microscopy revealed marked poikilocytosis and Heinz body formation in red blood cells (RBCs) in both the sinus and cord. Histiocytes were swollen by a granular substance in the cytoplasm and also many secondary lysosomes. These morphological findings indicate that degradation of damaged RBCs induced by exposure to Cd might be promoted in the spleen and possibly cause splenomegaly. This RBC damage-hemolysis-splenomegaly sequence is also considered to be associated with the etiology of Cd-induced anemia. In addition to the abnormal RBC degradation, nuclei of lymphocytes in the Cd-exposed spleen exhibited high electron density, consistent with a preapoptotic state suggesting the immunosuppressive effect of Cd.

Anemia↗

PubMed1998

Altered membrane skeleton of red blood cells participates in cadmium-induced anemia.

Poikilocytosis of red blood cells (RBCs) was observed to be associated with anemia in rats given subcutaneous injections of cadmium (Cd). Phase-contrast light and scanning electron microscopic examinations revealed that acanthocytes appeared in the early stages of administration, and that the number of RBC fragments increased later. Ultrastructural analysis of RBC ghosts by negative staining demonstrated that the normal lattice structure of the membrane skeleton was abolished. The osmotic fragility curve of the Cd-exposed RBCs disclosed that most of the cells were less fragile than control RBCs. These data indicate that the RBC membrane skeleton is initially altered by Cd-exposure, followed by deformation of the cell, thus promoting intrasplenic hemolysis, and resulting in anemia.

Acanthocytes↗

PubMed1998

Examination of nerve distribution to masticatory muscles using a silicone permeation technique.

The detailed anatomical distribution of nerves throughout the human body has generally been studied by dissection of fixed cadavers in liquid. In this traditional method, it is difficult to maintain the position of nerves on their respective muscles. It is also difficult to keep the distributed form of the nerves. To understand the morphology of nerves, it is essential to determine their location and distribution precisely. In this study the masseter muscle was removed from a cadaver after fixation with formalin. The muscle was then permeated with silicone using the following procedure. The muscle fixed by 10% formalin was dehydrated with alcohol. After dehydration, alcohol was replaced with methylene chloride. The sample was permeated by silicone in a permeater. Following dissection, enamel was applied to the nerve by hand to fix its position. This new permeation method provided excellent localization of nerves innervating the muscle and has the added advantage of providing a three-dimensional structure of neural anatomy similar to the casting procedures used to visualize blood vessels.

Diffusion↗

PubMed1998

Anatomical study of the maxillary tuberosity in Japanese men.

The placement of dental implants in the molar region of the maxilla is often difficult because of the presence of the maxillary sinus. It has recently been postulated that the pillar of bone consisting of the maxillary tuberosity, the pterygoid process of the sphenoid bone, and the pyramidal process of the palatine bone, which is located at the posterior part of the maxilla, is suitable for fixing implants in the maxilla. In this study, we morphometrically examined the figure of the pillar of bone in dentate and edentulous maxillary bone specimens. The posterior part of the maxilla, including the pterygoid process of the sphenoid bone and pyramidal process of the palatine bone was embedded in polyester resin. Serial transverse sections 500 microns thick were prepared, and soft X-ray photographs were taken. Three-dimensional images of the pillar of bone were reconstructed from the contour in the soft X-ray images, and the height inclination angles, and volume of the pillar were measured. In dentulous specimens, the imaginary approximation line of the center of the gravity of the pillar of bone in the posterior part of the maxilla was inclined antero-posteriorly at an angle of 76.5 +/- 3.0 degrees from the anterior to posterior direction against the Frankfurt horizontal plane and bucco-palatally at 17.2 +/- 2.7 degrees to the medial direction against the sagittal plane. In edentulous specimens, the pillar of bone was inclined antero-posteriorly at 67.3 +/- 5.0 degrees against the Frankfurt horizontal plane and bucco-palatally at 14.1 +/- 2.1 degrees against the sagittal plane. The volume of the pillar of bone was greater in edentulous specimens than those in the dentulous specimens. The present results will enable setting up a standard for implant surgery dentulous specimens.

Alveolar Process↗

PubMed1998

Mechanical properties of buccal compact bone of the mandibular ramus in human adults and children: relationship of the elastic modulus to the direction of the osteon and the porosity ratio.

With recent advances in computers, the finite element method has been used for stress analysis of bone. In particular, the dynamic behavior of the jaw bone has been a subject of interest and analyzed by this method. However as the elastic modulus needed for this method, a uniform value is used without considering differences according to site or direction. Therefore, we measured the elastic modulus at various sites and in various directions of the mandible in adults and children. In addition, the association between the elastic modulus and histological structures was evaluated. Ten specimens of dried mandible from human adults and children were used. The elastic modulus was measured in two regions prepared by equally dividing the ramus of the mandible into lower and upper regions. Samples of 6 mm x 960 microns x 425 microns were collected from the buccal compact bone. The elastic modulus was measured using a three-point bending test. After measurement, the direction of the osteon was examined using SEM. The porosity ratio was also measured after CMR were taken. In both adults and children, anisotropy in the elastic modulus of each direction in the upper region was similar to the anisotropy in unidirectional fiber reinforced composite materials, but not in the lower region. The elastic modulus decreased slightly with an increase in the angle of the direction of osteons to the longitudinal axis of specimens. The direction of osteon may significantly influence anisotropy in the elastic modulus. The elastic modulus in adults was higher than in children in all directions. The porosity ratio in adults was smaller than that in children in all directions. The difference in the porosity ratio between adults and children may significantly influence the value of the elastic modulus.

Adult↗

PubMed1998

A study of the internal structure of the mandibular ramus in Japanese.

To clarify the internal structure of the mandibular ramus in Japanese adults, we performed bone morphometry. Specimens were obtained from four areas: the mid-area between the mandibular foramen and the lowest point of the mandibular notch, areas immediately above and below the mandibular foramen, and the mid-area between the mandibular foramen and the mandibular angle. The mandibular ramus was divided into the anterior and posterior parts, and morphometric analysis was performed on the four areas in each part. The percentage of the trabecular bone area in spongy bone was higher in the anterior part than in the posterior part. In both the anterior and posterior parts, the percentage of trabecular bone was the highest in the most inferior area. Trabecular bone was thicker in the anterior part than in the posterior part. Both in the anterior and posterior parts, trabecular bone was the thickest in the most inferior area. The arrangement of trabecular bone was more complicated in the anterior part than in the posterior part. Trabecular bone was most frequently arranged in the anteroposterior direction. In the superior area of the posterior part, much trabecular bone ran from the posterior buccal side toward the anterior lingual side. Compact bone was thicker in the anterior part than in the posterior part and on the buccal side than on the lingual side. No age-related changes were observed in any element of trabecular bone structure.

Aged↗

PubMed1998

Attachment of the sphenomandibular ligament to bone during intrauterine embryo development for the control of mandibular movement.

The present study examined the relationship between jaw movement and the site of attachment of the sphenomandibular ligament, which is involved in the control of lateral jaw movement. Major fibers of this ligament are attached to the sphenoid spine and the mandibular lingula. During early stages of embryonic development, however, this ligament is not attached to the sphenoid spine. No consensus has yet been reached concerning the time at which this ligament becomes attached to this spine. The present study was performed to resolve this question and to analyze the relationship of this event of jaw movement. Attachment of the sphenomandibular ligament to the sphenoid spine was observed in fetuses at a gestational age of about 8 months (32 weeks). This may be because fetuses undergo functional changes (initiation of jaw movement such as mastication and swallowing) at this gestational age. This finding suggests that the attachment of the sphenomandibular ligament to the sphenoid spine may be related to fetal jaw movements.

Embryonic and Fetal Development↗

PubMed1998

Morphometric study of skin grooves of the head and neck.

The skin surface contains furrows called wrinkles, Langer's lines, and skin grooves that are characteristic ultrastructures of the skin. When a skin incision line is determined, these features should be considered. Many studies have examined skin wrinkles, the number of which increases with age. Langer's lines have also been studied extensively in cadavers. However, these studies may not consistently reflect Langer's lines in living individuals. Most of the studies of skin grooves have examined dermatoglyphics such as fingerprinting, palm printing, and sole printing. Very few studies have examined skin grooves in other areas or quantified their characteristics. The present study analyzed skin grooves of the head and neck in relationship to age, sex, and region. Subjects consisted of 50 nursery school children aged 6 years, 50 college students aged 20 years, and 50 adults aged over 60 years. Impressions were obtained from: 1) forehead, 2) root of the nose, 3) lateral ocular angle, 4) cheek, and 5) neck. The samples were cut into cubes (5.0 x 5.0 x 1.0 mm) and ion-coated with Au-Pdin by a cool sputter coater. Then scanning electron micrographs (x 50) were taken and analyzed by computer morphometry CB-TASPER. Densities of skin grooves and the specific length representing the complexity of grooves per unit area were analyzed using computer morphometry CB-TASPER software. The density of skin grooves differed according to the area, especially among samples taken from the forehead, root of the nose, and the neck. Females had more grooves than males, particularly in the neck region. Skin grooves decreased with age; they appear to change and be absorbed by increasing wrinkles, thus becoming indistinct.

Adult↗

PubMed1998

Histological study of the healing process of the attachment site of rat masseter muscle following injury.

The masseter muscle functions by attaching itself to the mandible. Thus, it is important to study the relationship between the masseter muscle and mandible to clarify the complex movement of the jaw. In this study, the chronological changes in the attachment site of the masseter muscle to the mandible following injury were observed in rats. These findings suggest that, in order for the masseter muscle to recover after injury, the tendinous fibers must be repaired, so that the entire muscle can be protected and recover functionality to some degree.

Animals↗

PubMed1997

Hepatitis C virus NS5A protein is phosphorylated in vitro by a stably bound protein kinase from HeLa cells and by cAMP-dependent protein kinase A-alpha catalytic subunit.

Hepatitis C virus (HCV) has a positive-strand RNA genome that codes for a polyprotein precursor, which is processed co- and post-translationally by cellular and viral proteinases into three structural and at least six non-structural (NS) proteins. The NS5A protein, expressed in mammalian cells, exists in two phosphorylated forms of 56-kDa and 58-kDa. In this study, we provide evidence for a stable association between NS5A and a protein kinase from HeLa cells and hepatocellular carcinoma (HepG2) cells by co-immunoprecipitation and by affinity to immobilized glutathione-S-transferase (GST)-NS5A fusion protein produced in E. coli. This protein kinase could phosphorylate in vitro the native NS5A on serine residues, (GST)-NS5A, histone H1, and casein as substrates. In addition, the GST-NS5A was also phosphorylated in vitro by the cAMP-dependent protein kinase A-alpha catalytic subunit.

Binding Sites↗

PubMed1997

Reduced auditory P300 amplitude, medial temporal volume reduction and psychopathology in schizophrenia.

Twenty-five schizophrenic patients diagnosed by DSM-III-R underwent event-related potentials and magnetic resonance imaging scans. Latency and amplitude of P300 waveform were measured using an auditory odd-ball paradigm. Anterior and posterior volumes of the superior temporal gyrus and medial temporal structure were measured from contiguous coronal images using the level of the mammillary body as an anatomical landmark. Principal component analysis of P300 latency and amplitude disclosed two orthogonal independent factors each: overall latency and residual, and amplitudes from posterior and anterior recordings, respectively. Structural volumes consisted of four orthogonally independent factors: left superior temporal volume, anterior medial temporal volume, right superior temporal volume, and posterior medial temporal volume. The factor score of the P300 amplitude from posterior recordings correlated with the factor score of volumetric changes in the anterior medial temporal structures. The present study failed to replicate a previously reported association between auditory P300 amplitude and superior temporal volume. Furthermore, the factor score of the P300 amplitude was correlated with the severity of clinical ratings of attentional impairments and positive thought disorder. These findings demonstrate that the information processing dysfunction of schizophrenia indicated by reduced P300 amplitude is associated with structural abnormality in the medial temporal lobe.

Adult↗

PubMed1997

The amino terminal deletion mutants of hepatitis C virus nonstructural protein NS5A function as transcriptional activators in yeast.

To investigate the biological function of hepatitis C virus (HCV)-NS5A, the NS5A was fused at its N-terminus with the DNA binding domain (DBD) of yeast transcriptional activator GAL4 (GAL4-DBD). The GAL4-DBD alone had no transcriptional activation function. However, a mutant of the GAL4-DBD/NS5A fusion protein, in which 129 amino acid residues were deleted from the N-terminus of NS5A, exhibited strong transcriptional activation in yeast cells, bearing the Escherichia coli lacZ reporter gene encoding the beta-galactosidase under the transcriptional control of GAL4 promoter and TATA box. Further mutational analysis of NS5A revealed that the region between the amino acid residues 130 to 352 were critical for optimal level of transactivation. This region includes two acidic domains and one proline-rich region which have been shown to be involved in the function of several transcriptional activators.

Gene Expression Regulation, Viral↗

PubMed1997

Immuno-scanning electron microscope characterization of large tubules in human deciduous dentin.

BACKGROUND: This study was undertaken to elucidate the type and origin of collagen fibrils which construct the large tubules in deciduous coronal dentin by scanning electron microscope and anti-types I and III collagen antibody procedures. METHODS: The studies were performed on human deciduous teeth. The teeth were fixed in 4% paraformaldehyde solution and then fractured either mesio-distally parallel to the long axis of the tooth or transversely perpendicular to the long axis of the tooth crown. The specimens were three-dimensionally observed employing the scanning electron microscope to distinguish the content of large tubules. Polyclonal antibodies of anti-type I and anti-type III collagen with 20 nm colloidal gold, and secondary electron imaging and backscatter electron imaging of high-resolution field emission scanning electron microscopy were used to examine the types of collagen fibrils. RESULTS: The large tubules extended from the vicinity of the incisal edge of the dentino-enamel junction to the pulp cavity. Inside the large tubules, fibers in compact bundles run parallel to the longitudinal axis of the tubules. The fiber bundles consisted of collagen fibrils which were 50-150 nm in diameter with typical cross striation. Immuno-scanning electron microscopy showed type I collagen-labelling gold particles and type III collagen-labelling gold particles to be abundant on the fibrils. Types I and III collagen-labelling gold particles were present on the banded collagen fibrils regardless of their diameter. CONCLUSIONS: It was found that type III collagen is present together with type I collagen on the fibrils constructing the large tubules of the human deciduous dentin. This immunohistochemical study suggested that the fibrils constructing the large tubules were derived from the von Korff fibers, and types I and III collagens formed copolymers.

Child↗

PubMed1997

Pure akinesia manifested neuroleptic malignant syndrome: a clinical variant of progressive supranuclear palsy.

An autopsy case of pure akinesia (PA) is reported. The patient manifested L-dopa-unresponsive akinesia without accompanying rigidity, tremor, eye movement disorder or dementia from the age of 58 years. Brain magnetic resonance T2-weighted imaging at the age of 63 showed high intensity areas in the subthalamic regions, but brain atrophy was not observed. She received amantadine-HCl and L-threo-3,4-dihydroxyphenylserine (L-DOPS) for 5 years. At the age of 66, she died of the severe illness accompanied by consciousness disturbances, hyperthermia, muscle rigidity, abnormal blood pressure and elevated serum enzymes which were derived from the muscle. We considered her condition to be neuroleptic malignant syndrome (NMS). Pathologically the brain revealed degeneration in the subthalamic nucleus, globus pallidus and substantia nigra. Neurofibrillary tangles were detected in the temporal cortex, hippocampus, amygdaloid body and spinal cord, as well as in the basal ganglia, thalamus and brain stem. These findings were consistent with that of progressive supranuclear palsy (PSP); the change in the ventral pons was insignificant, suggesting that PA may have minimum involvement in the ventral pons. The skeletal muscle showed scattered necrosis that was compatible with NMS. As far as we know, this is the first report of NMS accompanied with PA.

Brain↗

PubMed1997

The effects of an intrathecal NMDA antagonist (AP5) on the behavioral changes induced by colorectal inflammation with turpentine in rats.

Visceral pain, especially that associated with inflammation of visceral organs, is poorly understood and difficult to treat clinically. The purpose of this study was to investigate the effects of intrathecal 2-amino-5-phosphonovaleric acid (AP5, a competitive NMDA antagonist) upon a visceromotor response to distension of colonic tissue inflamed by exposure to turpentine. All experiments were conducted under pentobarbital anesthesia. Animals were prepared with a laminectomy from T12 to L1 to facilitate intrathecal drug administration. Colonic distension thresholds for a visceromotor response were determined in the presence and absence of AP5. Animals were divided into two groups. The NS group received 50 microl of saline intrathecally and the AP5 group 10 mM of AP5 in 50 microl saline. After baseline measurements, intrathecal drugs were administered. Five minutes later, the effects of intrathecal drugs were measured, then 1 ml of 25% turpentine was administered anorectally. Subsequent measurements were made every 5 minutes for the next 90 minutes. Visceromotor thresholds to colorectal distension (CRD) were significantly decreased 50 min after turpentine administration in the NS group. There was no threshold change in the AP5 group. This study suggests that the administration of the competitive NMDA receptor antagonist AP5 in this model blocks the effect of turpentine sensitization on visceromotor response to CRD. The absence of AP5 effects in animals not sensitized by turpentine suggests that NMDA systems may be involved in the sensitization.

2-Amino-5-phosphonovalerate↗

PubMed1997

The role of transforming growth factor-beta in PEG-rHuMGDF-induced reversible myelofibrosis in rats.

Pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) injected at a suprapharmacologic dose (100 microg/kg) daily for 5 d in normal rats caused marked increases in marrow megakaryocytes and platelet counts at 6-8 d followed by gradual decreases to control levels at 10-20 d. Interestingly, in addition to the expected thrombopoiesis, PEG-rHuMGDF was associated with myelofibrosis with a predominance of reticulin fibres at day 10 followed by complete normalization by day 20. At 6-8 d, the levels of transforming growth factor-beta1 (TGF-beta1) in the extracellular fluid of the marrow, the platelet poor plasma, and the platelet extract were increased 23-, 7- and 2-fold, respectively. The elevated levels of TGF-beta1 were gradually reduced to baseline levels at 13-20 d in accordance with the normalization of myelofibrosis and thrombopoiesis. An ultrastructural analysis showed that large fragments of megakaryocytes were deposited in the marrow parenchyma of PEG-rHuMGDF-treated rats at day 6. PEG-rHuMGDF administration at pharmacologic doses (1 and 10 microg/kg) did not induce the deposition of reticulin fibres in the marrow. These findings suggest that TGF-beta1 leaked from megakaryocytes is involved in the development of the PEG-rHuMGDF-induced myelofibrosis and that this is a reversible process related to the regulation of the excess production of platelets.

Animals↗

PubMed1997

Perspectives on the role of the lateral pterygoid muscle and the sphenomandibular ligament in temporomandibular joint function.

The lateral pterygoid muscle plays an important role in the movement of the mandible and has been studied from several points of view, including structural and functional anatomy. What matters clinically is the relative position of the muscle fibers attached medially to the mandibular condyle. In the following study, we observed not only the attachment of the lateral pterygoid muscle fibers to the articular disk, but also the relative position of the mandibular condyle to a base line set up on the mandibular condyle. According to our observations, the lateral pterygoid muscle fibers attach to the articular disk at the inner point of the medial pole. Based on this finding, we can say that the muscle fibers can both draw the articular disk anteriorly and balance it by supporting it posteriorly. That is to say, the lateral pterygoid muscle has two actions: to elevate the articular disk anteriorly and to support the articular disk. Furthermore, the sphenomandibular ligament has continuity with the articular disk tissue medially. This relationship suggests that the ligament fibers attached to the articular disk draw the disk posteriorly in its course of mandibular closing, thus enabling the articular disk to move smoothly.

Adult↗