Biomedical subjects

K Kaneda

Publications and source records attributed to K Kaneda.

At least 199 records · Page 11Linked to original sources

PubMed1997

Protective effects of methylcobalamin, a vitamin B12 analog, against glutamate-induced neurotoxicity in retinal cell culture.

PURPOSE: To examine the effects of methylcobalamin on glutamate-induced neurotoxicity in the cultured retinal neurons. METHODS: Primary cultures obtained from the fetal rat retina (gestation days 16 to 19) were used for the experiment. The neurotoxicity was assessed quantitatively using the trypan blue exclusion method. RESULTS: Glutamate neurotoxicity was prevented by chronic exposure to methylcobalamin and S-adenosylmethionine (SAM), which is formed in the metabolic pathway of methylcobalamin. Chronic exposure to methylcobalamin and SAM also inhibited the neurotoxicity induced by sodium nitroprusside that release nitric oxide. By contrast, acute exposure to methylcobalamin did not protect retinal neurons against glutamate neurotoxicity. CONCLUSIONS: Chronic administration of methylcobalamin protects cultured retinal neurons against N-methyl-D-aspartate-receptor-mediated glutamate neurotoxicity, probably by altering the membrane properties through SAM-mediated methylation.

Animals↗

PubMed1997

[Back pain and neurological deficits in osteoporotic spinal fractures].

Generally osteoporotic compression fractures of the spine cause only localized pain and kyphosis without other significant complications. These fractures usually heal without difficulty by conservative treatment. However, it becomes to be accepted as a general concept that a small number of patients with osteoporotic fracture of the thoracolumbar spine result in delayed vertebral body collapse with neural compromise. We analyzed our series of osteoporotic-posttraumatic vertebral collapse. We had treated 51 consecutive patients with posttraumatic vertebral collapse following osteoporotic compression fractures of the thoracolumbar spine between Jan. 1987 and June 1994. Surgery consisted of anterior spinal reconstruction by strut grafting using a bioactive ceramic vertebral prosthesis (A-WGC) and autogenous rib in combination with the Kaneda device after resecting the collapsed vertebral bodies. After surgery, 80% of the patients with initial neurological deficits showed remarkable neurological recovery. The causes of neural compression were retropulsion of the posterior part of the collapsed vertebral body into the spinal canal and unstable kyphosis. The collapsed portion of the resected vertebral bodies was always less bloody or ischemic. Histology confirmed ischemic necrosis of the collapsed portion. The collapse would be resulted in by the compromised healing process due to repeated micro-traumas to the fragile trabecular bone following osteoporotic vertebral fracture. Autogenous iliac bone as well as fibula cannot be used as another alternative strut graft because of the fragility of the graft and grafted site. The anterior reconstruction with a bioactive ceramic vertebral prosthesis and the Kaneda device has been useful in osteonecrotic-posttraumatic vertebral collapse of the thoracolumbar spine.

Aged↗

PubMed1996

IFN-gamma-inducing factor up-regulates Fas ligand-mediated cytotoxic activity of murine natural killer cell clones.

NK cells, non-T non-B immune effector lymphocytes, are localized in many organs, including liver, as well as in the circulation. To investigate the regulatory mechanism of killing apparatus in hepatic NK cells, we established IL-2-dependent NK cell clones from liver lymphocytes of BALB/c nude mice. To generate the NK cell clones, we incubated liver lymphocytes with a high dose of IL-2 in the presence of irradiated Kupffer cells, as feeder cells and as the source of IL-12, originally identified as NK cell stimulatory factor. Unless liver lymphocytes were incubated with both IL-2 and Kupffer cells, no cell growth was observed. Hepatic NK cell clones were established from this cell line by limiting dilution. The surface phenotypes of cloned NK cells were IL-2R beta-chain+ CD16+ CD3- IgM-. The clones did not express NK2.1, which is expressed by a half of NK-enriched spleen cells of BALB/c mice. Although the cells contained dense granules reactive to mAb against perforin, they exerted no conventional cytolytic activity against YAC-1. They constitutively expressed Fas ligand (FasL) and specifically killed Fas-positive target cells by fragmenting DNA. This Fas-FasL-mediated killing activity was enhanced by IFN-gamma-inducing factor, a recently identified novel cytokine produced by activated Kupffer cells, but was not affected by other Kupffer cell-produced cytokines, such as IL-12, IL-1beta, and TNF-alpha. Taken together, these findings suggest that hepatic NK cells participate in the immune response as effector cells through the Fas-FasL system in collaboration with cytokines from Kupffer cells.

Animals↗

PubMed1996

Characterization of Borrelia sp. isolated from Ixodes tanuki, I. turdus, and I. columnae in Japan by restriction fragment length polymorphism of rrf (5S)-rrl (23S) intergenic spacer amplicons.

Borrelia isolated from various sources in Japan, including rare species of ixodid ticks, Ixodes tanuki, I. turdus, and I. columnae, were characterized by restriction fragment length polymorphism analysis and sequencing analysis of the 5S-23S rRNA intergenic spacer amplicon. Borrelia sp. isolated from I. tanuki, I. turdus and I. columnae generated restriction fragment length polymorphism patterns different from those of known B. burgdorferi sensu lato isolates previously reported. Furthermore, some B. afzelii and B. garinii isolated in Japan showed unique RFLP patterns which were not observed among European B. afzelii and B. garinii.

Animals↗

PubMed1996

Phase lag of the intersegmental motion in flexion-extension of the lumbar and lumbosacral spine. An in vivo study.

STUDY DESIGN: The lumbar and lumbosacral segmental motions were analyzed in vivo using cineradiographic method. OBJECTIVES: To reveal the in vivo motion behavior of the lumbar and lumbosacral segments and their contribution to the whole lumbar motion. SUMMARY OF BACKGROUND DATA: Relation between the lumbar motion and hip joint motion has been well investigated. The lumbar motion preceded the hip flexion in forward bending and delayed from extension of the hip joints in backward bending. However, it remains unclear how the lumbar and lumbosacral segmental motion contributed to the whole lumbar motion in vivo. METHODS: Eight healthy male subjects participated in this study. The lower lumbar and lumbosacral motion (L3-S1) was recorded using cineradiography during flexion and extension. Each trunk motion was carried out from the neutral position to the maximum position. Segmental rotation and translation were measured sequentially at the L3-L4, L4-L5, and L5-S1 motion segments. RESULTS: Intersegmental motion lags were observed between the lumbar and lumbosacral motion segments during flexion. The lower lumbar and lumbosacral motion (L3-S1) was initiated at the L3-L4 motion segment. The L4-L5 segmental motion delayed from the L3-L4 motion by an average of 6 degrees and preceded the L5-S1 motion by an average of 8 degrees. In extension, motions in the L3-L4 and L4-L5 segments were small, and the L5-S1 segmental motion only contributed to the total lower lumbar motion. CONCLUSIONS: The lumbar and lumbosacral segmental motions occurred not simultaneously but stepwise from the upper level with intersegmental motion lags during flexion. These intersegmental motion lags were much larger than the neutral zone in vitro, which implied the neutral zone in vivo should be different from the neutral zone in vitro.

Adolescent↗

PubMed1996

Biomechanical role of the posterior elements, costovertebral joints, and rib cage in the stability of the thoracic spine.

STUDY DESIGN: This is a biomechanical study of the thoracic spine. Various ligaments and joints were resected sequentially and nondestructive cyclic loading tests were performed. Effects of each resection were analyzed biomechanically. OBJECTIVES: To investigate the role of the posterior elements, costovertebral joints, and rib cage in the stability of the thoracic spine. SUMMARY OF BACKGROUND DATA: There have been no experimental studies concerning the mechanical interaction between the thoracic spine and rib cage. METHODS: Eight canine rib cage-thoracic spine complexes, consisting of the sixth to eighth ribs, sternum, and T5-T9 vertebrae, were used. Six pure moments along three axes were applied to the specimens, and angular deformation of T6-T7 was recorded. After testing the intact specimen, resection of the stabilizers was conducted incrementally in the following manner: 1) removal of the posterior elements at T6-T7, 2) resection of the bilateral seventh costovertebral joints, and finally, 3) destruction of the rib cage. The same loading tests were repeated at each stage. The ranges of motion and neutral zones were calculated by digitization. RESULTS: A large increase in the range of motion in flexion-extension was observed after resection of the posterior elements and in lateral bending and axial rotation after resection of the costovertebral joints. A significant increase in the neutral zone in lateral bending and axial rotation was observed after bilateral resection of the costovertebral joints and destruction of the rib cage. CONCLUSIONS: The costovertebral joints and rib cage play an important role in providing stability to the thoracic spine. The state of the costovertebral joints and rib cage should be assessed to evaluate the stability of the thoracic spine.

Animals↗

PubMed1996

New anterior instrumentation for the management of thoracolumbar and lumbar scoliosis. Application of the Kaneda two-rod system.

STUDY DESIGN: The Kaneda multisegmental instrumentation is a new anterior two-rod system for the correction of thoracolumbar and lumbar spine deformities. This system consists of a vertebral plate and two vertebral screws for individual vertebral bodies and two semirigid rods to interconnect the vertebral screws. Clinical results of 25 thoracolumbar and lumbar scoliosis patients treated with this new instrumentation were analyzed. OBJECTIVES: To evaluate the efficacy of the new anterior instrumentation in correction and stabilization of thoracolumbar and lumbar scoliosis. SUMMARY OF BACKGROUND DATA: Since Dwyer first introduced the concept of anterior spinal instrumentation and fusion for scoliosis, anterior surgery has gradually gained acceptance. In 1976, a useful modification for the anterior spinal instrumentation, which reportedly provided means of lordosation and vertebral body derotation, was described. However, some authors reported a high tendency of the implant breakage, loss of correction, progression of the kyphosis, and pseudoarthrosis as the major complications. To overcome the disadvantages of Zielke instrumentation, the authors have developed a new anterior spinal instrumentation (two-rod system) for the management of thoracolumbar and lumbar scoliosis. METHODS: Anterior correction and fusion using Kaneda multisegmental instrumentation was performed in 25 patients with thoracolumbar or lumbar scoliosis. The average follow-up period was 3 years, 1 month (range, 2 years to 4 years, 7 months). There were 20 patients with idiopathic scoliosis (13 adolescents and seven adults) and five patients with other types of scoliosis, including congenital and other etiologies. All patients had correction of scoliosis by fusion within the major curve, and for 16 of the 25 patients, the most distal end vertebra was not included in the fusion (short fusion). Radiographic evaluations were performed to analyze frontal and sagittal alignments of the spine. RESULTS: The average correction rate of scoliosis was 83%. Over the instrumented levels, the correction rate was 90%. Preoperative kyphosis of the instrumented levels of 7 degrees was corrected to 9 degrees of lordosis. Sagittal lordosis of the lumbosacral area beneath the fused segments averaged 51 degrees before surgery and was reduced to 34 degrees after surgery. The trunk shift was improved from 25 mm before surgery to 4 mm at final follow-up evaluation. The average improvement in the lower end vertebra tilt-angle was 97% in those patients whose lower end vertebra was included in the fusion and 83% in patients whose lower end vertebra was not included in the fusion. Apical vertebral rotation showed an average correction rate of 86%. At final follow-up evaluation, all patients demonstrated solid fusion without implant-related complications. There was 1.5 degrees of frontal plane and 1.5 degrees of sagittal plane correction loss within the instrumented area at final follow-up evaluation. CONCLUSIONS: New anterior two-rod system showed excellent correction of the frontal curvature and sagittal alignment with extremely high correction capability of rotational deformities. Furthermore, correction of thoracolumbar kyphosis to physiologic lordosis was achieved. This system provides flexibility of the implant for smooth application to the deformed spine and overall rigidity to correct the deformity and maintain the fixation without a significant loss of correction or implant failure compared with conventional one-rod instrumentation systems in anterior scoliosis correction.

Adolescent↗

PubMed1996

Effects of degeneration on the elastic modulus distribution in the lumbar intervertebral disc.

STUDY DESIGN: Local elastic moduli of sliced intervertebral disc specimens were studied after establishing the relation between the elastic modulus and indentation behaviors by model tests using polyurethane specimens. OBJECTIVES: This study presents a method to quantify the distribution of compressive elastic moduli in the lumbar intervertebral disc and to clarify the effects of degeneration on the distribution. SUMMARY OF BACKGROUND DATA: No study has been performed to evaluate the distribution of axial compressive elastic moduli, which is supposed to relate previous biomechanical, biological, and biochemical findings regarding the intervertebral disc. METHODS: Local compressive elastic moduli of the intervertebral disc were estimated by indentation tests. To evaluate the distribution of elastic moduli, indentation tests were performed at nodal points of a 10 mm x 10 mm network on a specimen. Nine cadaveric lumbar discs (L3-L4 and L4-L5) with various degrees of degeneration were tested. The age of subjects ranged 39 to 90 years (mean, 58.4 years). RESULTS: The distribution of elastic moduli in normal discs was symmetric about the midsagittal plane. The mean elastic modulus in the nucleus pulposus was 5.8 kPa and those of the anterior and posterior anulus fibrosus were 110.7 and 75.8 kPa, respectively. The elastic moduli in the lateral portions were the lowest in the normal anulus, and were close to the values of the nucleus. Compared to normal discs, degenerated discs showed irregular distributions of elastic moduli. The elastic moduli of the degenerated nucleus were higher than those in normal discs. CONCLUSIONS: The distribution of elastic moduli is much different between discs with and without degeneration.

Adult↗

PubMed1996

Dual actions of nitric oxide in N-methyl-D-aspartate receptor-mediated neurotoxicity in cultured retinal neurons.

This study was performed to elucidate the role of nitric oxide (NO) in N-methyl-D-aspartate (NMDA) receptor-mediated glutamate neurotoxicity in the retina. The experiments were done with primary retinal cultures obtained from 17- to 19-day-old rat fetuses. The NOS activity measured by monitoring the conversion of [3H]arginine to [3H]citrulline was approximately 5 pmol/min/mg protein. A 10-min exposure of the cultured cells to glutamate (1 mM) or NMDA (1 mM) followed by a 1-h incubation in a normal medium consistently resulted in 60% cell death. The concomitant addition of an inhibitor of NOS, Nomega-nitro-L-arginine (300 microM), with glutamate or NMDA reduced cell death by 70%. A brief exposure of the cells to sodium nitroprusside (SNP, 500 microM) or S-nitrosocysteine (SNOC, 500 microM), NO-generating agents, caused 60% cell death. Depletion of NO by reduced hemoglobin prevented the cell death induced by either glutamate, NMDA, or NO generating agents. Fifty microM SNOC alone had no effect on the cell viability. However, pretreatment with 50 microM SNOC as well as simultaneous application of 50 microM SNOC with NMDA inhibited cell death induced by NMDA. These findings indicate that a low concentration of NO plays a protective role in glutamate neurotoxicity via closing the NMDA receptor gated ion channel. However, elevated concentrations of NO, interacting with oxygen radicals, become toxic and mediate glutamate-induced neurotoxicity in the cultured retinal neurons.

Animals↗

PubMed1996

The role of spinal instrumentation in augmenting lumbar posterolateral fusion.

STUDY DESIGN: Using a sheep model, clinically practical posterolateral intertransverse process fusion was successfully achieved and biomechanically tested to determine the load-sharing environment provided by spinal instrumentation and posterolateral fusion mass following solid arthrodesis. OBJECTIVES: To quantify the in vivo load-sharing capacity of spinal instrumentation on augmenting the posterolateral intertransverse fusion. The hypothesis was that transpedicular screw fixation maintains the biomechanical contribution to the posterolateral fusion stability even after successful arthrodesis because of its providing anterior and middle column support. SUMMARY OF BACKGROUND DATA: Although many previous studies have documented the biological and biomechanical advantages of posterolateral fusion, it is known that posterolateral fusion without spinal instrumentation allowed significant remaining motion at the fused segment even after the solid arthrodesis. Whether spinal instrumentation, especially transpedicular screw fixation, augments in vivo posterolateral fusion stability after solid arthrodesis has not been previously investigated. METHODS: Radiographic, macroscopic, and biomechanical analyses of a posterolateral intertransverse process fusion model were performed on 18 sheep at 4 months postoperatively. The load-sharing contribution of the spinal instrumentation was calculated based on the stability with or without spinal instrumentation tested in five loading modalities. Histomorphometry of the vertebral body spanned by spinal instrumentation provided the information regarding the biological effect of the load-sharing capacity of spinal instrumentation on bone remodeling. RESULTS: All sheep who received posterolateral intertransverse process fusion demonstrated successful solid arthrodesis and high biomechanical quality of the posterolateral fusion mass when compared to previous posterolateral fusion models. The significant difference in stiffness between fixation and subsequent fixation removal was observed in flexion, despite maintaining high lateral bending stiffness equivalent to the fixation (with instrumentation) level. This significant load-sharing contribution of spinal instrumentation detected in flexion corresponded to 27% when compared to the fixation level. The qualitative and quantitative bone histology showed 64% of the volumetric density of bone in the fixation group when compared to that of the sham group as well as narrow trabeculae and reduced connection of trabeculae. CONCLUSIONS: The continuance in support offered by transpedicular screw fixation was assured in vivo after the solid posterolateral intertransverse process fusion. This was clearly demonstrated under eccentric loads in a sagittal plane, suggesting that transpedicular screw fixation was able to provide anterior and middle column support and resist eccentric loads.

Analysis of Variance↗

PubMed1996

Mechanical properties of the anterior cruciate ligament chronically relaxed by elevation of the tibial insertion.

The effects of stress deprivation on the mechanical properties of the anterior cruciate ligament were studied in a canine model. Fifty-eight mature mongrel dogs were divided into two groups. In the relaxed group (n = 30), the tibial insertion of the anterior cruciate ligament in each right knee was surgically elevated proximally 3 mm from the tibia; the elevation was anatomically reduced in the sham group (n = 28). In order to obtain control data, the left knee in each dog was left untreated. A femur-anterior cruciate ligament-tibia complex was excised from each knee for biomechanical tests at 6 or 12 weeks after surgery. To simplify data analysis, the treat/nontreat ratio (the ratio of the data obtained from the treated knee to that from the nontreated knee) was used. The cross-sectional area of the ligament increased significantly in both groups; the area in the relaxed group (average treat/nontreat ratio = 1.37) was significantly larger than that in the sham group (1.16) at 6 weeks but not at 12 weeks. The treat/nontreat ratio of tensile strength in the relaxed group significantly decreased to 0.67 and 0.58 at 6 and 12 weeks, respectively; in the sham group, it significantly decreased to 0.79 at 6 weeks but subsequently increased to 0.87 at 12 weeks. Only at 12 weeks was a significant difference observed between the two groups. This study demonstrated that, in the anterior cruciate ligament, stress deprivation results in a rapid increase in the cross-sectional area, although this effect disappears by 12 weeks, and in a decrease in mechanical strength, although a relatively long period of more than 6 weeks is required for the deterioration.

Animals↗

PubMed1996

Biomechanical effects of stress shielding of the rabbit patellar tendon depend on the degree of stress reduction.

A rabbit model was used to discover whether the effects of stress shielding on the mechanical properties of the patellar tendon depend on the degree of stress reduction. Ninety mature female Japanese White rabbits were divided into three groups: completely stress-shielded partially stress-shielded and sham-operation and contralateral controls. In the experimental groups, tension applied to the patellar tendon was 0%, approximately 30%, and 100% of the normal tension, respectively, with a polyester artificial ligament. Tensile tests were carried out on patella-patellar tendon-tibia complexes harvested 1, 2, 3, 6, or 12 weeks after surgery. The tensile strength decreased in comparison with the sham-operation group to 50.2, 13.5, 9.7, and 20.7% in the completely stress-shielded group and to 75.2, 57.6, 59.6, 57.3, and 72.9% in the partially stress-shielded group. The tensile strength in the completely stress-shielded group was significantly less than that in the partially stress-shielded group at 1, 2, 3, and 6 weeks. The cross-sectional area of the patellar tendon significantly increased to 132, 206, 237, and 136% in the completely stress-shielded group and to 136, 170, 175, 155, and 127% in the partially stress-shielded group compared with the sham-operation group. The cross-sectional area of the completely stress-shielded tendon was significantly larger than that of the partially stress-shielded tendon at 1, 2, and 3 weeks. This study demonstrated that effects of stress shielding on the mechanical properties of the patellar tendon were dependent on the degree of stress shielding.

Animals↗

PubMed1996

Migration of an acupuncture needle into the medulla oblongata.

A case of a delayed lesion of the medulla oblongata caused by migration of an acupuncture needle is presented. The patient was a 60-year-old woman who had undergone embedded-type acupuncture needle treatment around 1975. In 1993 she was admitted to our hospital with a 3-week history of progressive motor and sensory disturbance of her right upper extremity. CT demonstrated that one needle had penetrated the medulla oblongata transversely at the level of the foramen magnum. The needle was removed surgically without any complications. This is the first report of an acupuncture needle migrating in the medulla oblongata.

Acupuncture Therapy↗

PubMed1996

Autoantibodies recognizing proteins copurified with PCNA in patients with connective tissue diseases.

OBJECTIVE: Proliferating cell nuclear antigen (PCNA), one of the target antigen recognized by lupus sera, has been reported to be present as a subnuclear multi-peptide complex. But autoantibodies reacting with components of PCNA complex are poorly understood. To study the specificity of those autoantibodies, immunoreactivities of autoimmune sera against purified PCNA antigen were studied. METHODS: PCNA antigens were purified from rabbit thymus extract by affinity column using murine monoclonal antibodies (mAbs) to PCNA, TOB7, TO17 and TO30. Immunoreactivities of autoimmune sera against purified PCNA were analyzed by WB. RESULTS: PCNA antigen purified by serum AK predominantly showed a 34 kD band specific for PCNA in SDS-PAGE. When antigens were purified by anti-PCNA mAb TOB7 and TO30 which are known to be targeting different epitopes on PCNA antigen, SDS-PAGE analysis showed various mol. wt of proteins in addition to the 34 kD PCNA while both AK and mAbs reacted only with 34 kD PCNA in WB. In WB using PCNA purified by TOB7, various immunoreactivities were observed at 150, 66, 58, 48, 45, 37, 32 and 16 kDa in sera from patients with connective tissue diseases. CONCLUSIONS: These results suggested that many of the proteins copurified with PCNA were also targets of autoimmune responses and these autoantibody expression may be induced through antigen-driven mechanisms.

Animals↗

PubMed1996

Inhibition of myofibroblastic transformation of cultured rat hepatic stellate cells by methylxanthines and dibutyryl cAMP.

Stellate cells isolated from rat liver and cultured on uncoated plastic plates in serum-containing medium started proliferating and transforming to myofibroblastic cells. However, stellate cells did not proliferate when cultured in the presence of 3-isobutyl-1-methylxanthine or dibutyryl cAMP (dBcAMP). These substances significantly reduced [3h] thymidine incorporation of the proliferating cells. Morphologically, stellate cells cultured in the presence of 3-isobutyl-1-methylxanthine or dibutyryl cAMP kept well-developed processes and lipid droplets while untreated cells exhibited myofibroblastic characteristics. Western blot analysis and immunocytochemical studies revealed that 3-isobutyl-1-methylxanthine and dBcAMP suppressed the expression of alpha-smooth muscle actin in stellate cells. 3-isobutyl-1-methylxanthine increased the cellular levels of cAMP from a basal value of 0.7 +/- 0.1 to 8.5 +/- 1.7 pmol/well in stellate cells. Thus, 3-isobutyl-1-methylxanthine and dBcAMP inhibit the myofibroblastic transformation of stellate cells in vitro in some cAMP-related mechanism.

Animals↗

PubMed1996

Expression of neural cell adhesion molecule (N-CAM) in perisinusoidal stellate cells of the human liver.

Neural cell adhesion molecule (N-CAM) is distributed in most nerve cells and some non-neural tissues. The present immunohistochemical study has revealed, for the first time, the expression of N-CAM in perisinusoidal stellate cells of the human liver. Liver specimens were stained with monoclonal antibody against human Leu19 (N-CAM) by a streptoavidin-biotin-peroxidase-complex method. Light- and electron-microscopic analyses have shown that N-CAM-positive nerve fibers are distributed in the periportal and intermediate zones of the liver lobule. Perisinusoidal stellate cells in these zones are also positive for N-CAM. N-CAM is expressed on the surface of the cell, including cytoplasmic projections. Close contact of N-CAM-positive nerve endings with N-CAM-positive stellate cells has been observed. On the other hand, stellate cells in the centrilobular zone exhibit weak or no reaction for N-CAM. Perivascular smooth muscle cells and fibroblasts in the portal area and myofibroblasts around the central veins are negative for N-CAM. The present results indicate that the perisinusoidal stellate cells in the periportal and intermediate zones of the liver lobule characteristically express N-CAM, unlike other related mesenchymal cells, and suggest that the intralobular heterogeneity of N-CAM expression by stellate cells is related to the different maturational stages of these cells.

Antibodies, Monoclonal↗

PubMed1996

Expression of heat-shock protein 47 in mouse liver.

Expression of heat-shock protein 47 in intact and fibrotic liver and in hepatic constituent cells was investigated in mice. Immunohistochemical study of intact liver and Western blot analysis of the protein from isolated liver cells revealed that stellate cells and smooth muscle cells of interlobular vessels, but not hepatocytes, Kupffer cells, or endothelial cells, expressed heat-shock protein 47. The protein was found in both vitamin-A-storing stellate cells and myofibroblast-like cells. The amount of the protein in cultured stellate cells was reduced by dexamethasone but was not regulated by quercetin, transforming growth factor beta, interferon gamma, or retinoic acid. In CCl4-treated or bile-duct-ligated mouse liver, the number of cells positive for heat-shock protein 47 markedly increased in the centrilobular area or around the periportal area, respectively, and the level of heat-shock protein 47 also increased.

Animals↗

PubMed1996

Morphological study of endothelin-1-induced contraction of cultured hepatic stellate cells on hydrated collagen gels.

Hepatic stellate cells become activated and aquire contractility on being cultured. In order to characterize the morphology of contracted and relaxed stellate cells, we performed light- and electron-microscopic analyses of cultured stellate cells on collagen gels. Incubation of stellate cells with medium alone, 10 nM endothelin (ET)-1, or 1 mM N6,2' dibutyryladenosine 3':5'-cyclic monophosphate (dBcAMP) for 48 h induced contraction of the underlying collagen gels to 83%, 57%, and 97%, respectively, of their original size. Stellate cells relaxed by dBcAMP exhibited a round cell body and extended several long thin cytoplasmic processes with several varicosities. Culture with ET-1 accelerated spreading of the stellate cells on collagen gels and decreased the number of processes. Each such flattened stellate cell attached itself to the underlying collagen matrix by bending its cell body. Collagen fibers around the cell were pulled toward the cell and stretched. Thus, the present study has revealed that ET-1-stimulated cultured stellate cells adduct associated collagen fibers by the retraction of cytoplasmic processes and the bending of their spread cell bodies.

Animals↗