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Biomedical subjects

K Tanji

Publications and source records attributed to K Tanji.

72 records · Page 4Linked to original sources
PubMed1995

Gap junctions between fibroblasts in rat myotendon.

We applied conventional and freeze-fracture electron microscopy to study intercellular contacts between the processes of fibroblasts in the myotendon of the rat exterior digitorium longus. The results showed well defined gap junctions between the cell processes, while other cell junctional structures such as tight junctions and desmosomes were not recognizable. The present study suggests that the gap junctions represent a structure to coordinate the activities of fibroblasts distributed in the myotendon of the muscle.

Animals↗
PubMed1994

Innervation of MyoD-converted human amniocytes and fibroblasts by fetal rodent spinal cord neurons.

MyoD is one member of a gene family involved in the regulation of myogenesis. MyoD transfection induces myogenesis in a variety of non-muscle cells. Human amniocytes and fibroblasts were infected with a MyoD-retrovirus vector, to determine whether the converted cells can mature normally to form functional muscle fibers. MyoD-converted cells were cocultured with fetal rat spinal cord. After 2-3 weeks of co-culture cross-striated, contracting muscle fibers were observed. Combined acetylcholinesterase cytochemistry and acetylcholine receptor labeling showed prominent staining at nerve-muscle contacts. Approximately half of the total creatine kinase activity was due to the muscle-specific isozyme. Innervated MyoD-converted cells might represent a new source of muscle cells for studying the molecular events leading toward the formation of functional muscle. This system also appears suitable for studying the pathogenesis of hereditary, often rare, myopathies affecting muscle-specific proteins, for which muscle tissue is frequently unavailable for in vitro analysis.

Adult↗
PubMed1994

Abnormalities in the expression of beta-spectrin in Duchenne muscular dystrophy.

We studied beta-spectrin using an immunologic probe in muscle samples from patients with Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), other disease controls, and normal controls. By immunohistochemistry in DMD samples, beta-spectrin showed reduced or interrupted staining of the entire cell surface or only patches of bright staining at the cell periphery. There were also alterations of beta-spectrin immunostain in fibers that were not degenerating or regenerating. By immunoblotting, the amount of beta-spectrin in muscle was reduced and varied from 52% to 78% of the normal controls. We found normal values of beta-spectrin in BMD and disease controls. These observations indicate that the expression of beta-spectrin in DMD is abnormal and that beta-spectrin immunolabeling is not a good marker for monitoring membrane integrity in DMD muscle.

Adolescent↗
PubMed1993

Analysis of dystrophin expression after activation of myogenesis in amniocytes, chorionic-villus cells, and fibroblasts. A new method for diagnosing Duchenne's muscular dystrophy.

BACKGROUND: DNA analysis of peripheral-blood leukocytes is routinely used to demonstrate mutations in the dystrophin gene in patients with Duchenne's or Becker's muscular dystrophy. In approximately 35 percent of patients, DNA studies are not informative; in these patients immunochemical analysis of a muscle-biopsy specimen can determine whether dystrophin, the protein product of the gene for Duchenne's dystrophy, is present at reduced levels or absent. DNA analysis can be performed in amniocytes or chorionic-villus cells to identify mutations of the dystrophic gene prenatally, but immunochemical testing for dystrophin cannot be performed because the protein is not expressed in these cells. METHODS: To circumvent this limitation in prenatal diagnosis, we induced myogenesis in 21 cultures of skin fibroblasts, 49 amniocyte cultures, and 6 chorionic-villus cell cultures by infecting the cells with a retrovirus vector containing MyoD, a gene regulating myogenesis. Transfection of MyoD into cells that do not normally develop into muscle cells results in the production of a protein that switches on myogenesis. We performed immunocytochemical analysis for dystrophin in the MyoD-converted muscle cells. RESULTS: We found that 60 of 61 myotube cultures from subjects with no family history of Duchenne's dystrophy expressed dystrophin. Both myotube cultures from the two patients with Becker's dystrophy also expressed dystrophin, but all cultures from nine patients and two fetuses with Duchenne's dystrophy were dystrophin-deficient. CONCLUSIONS: Immunocytochemical analysis of dystrophin in genetically altered non-muscle cells is feasible and may be applicable to the prenatal and postnatal diagnosis of Duchenne's muscular dystrophy when conventional DNA analysis is not informative.

Amniotic Fluid↗
PubMed1993

Dystrophinopathy in two young boys with exercise-induced cramps and myoglobinuria.

Two young boys were referred for evaluation of metabolic myopathy because of elevated serum levels of creatine kinase, cramps and pigmenturia. Immunohistochemical studies of dystrophin in muscle biopsies showed reduced intensity of the stain with a patchy and discontinuous pattern in most fibers. In both patients dystrophin was undetectable by immunoblotting. DNA analysis of the dystrophin gene was not informative in one patient; in the other it revealed an in-frame deletion comprising exons 3-6. These observations suggest that the two patients are affected with an unusual phenotype of Becker muscular dystrophy. Dystrophin analysis should be included in the evaluation of patients with childhood-onset of recurrent myoglobinuria.

Child↗
PubMed1993

Immunolocalization of heat shock proteins in ragged-red fibers of patients with mitochondrial encephalomyopathies.

Monoclonal antibodies against the 60 kDa heat shock protein (HSP-60) and against ubiquitin (UB) were used to study the expression of these proteins in muscle samples from patients with qualitative and quantitative alterations of mitochondrial DNA (mtDNA). We found an enhanced expression of HSP-60 and UB that was preferentially localized in ragged-red fibers (RRFs). HSP-60 may act as a protein repair enzyme catalyzing the refolding of misfolded proteins in the matrix of mitochondria of RRFs. On the other hand, UB could promote the elimination of abnormal proteins by its covalent interaction to substrates.

Antibodies, Monoclonal↗
PubMed1993

MELAS point mutation with unusual clinical presentation.

Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) is a multisystemic mitochondrial disorder (Pavlakis et al. Advances in Contemporary Neurology. Philadelphia: Davis, 1988: 95-133) and most patients with the typical MELAS phenotype have a point mutation in mitochondrial DNA, an A to G transition at nucleotide 3243 (Goto et al. Nature 1990; 348; 651-653; Koboyashi et al. Biochem Biophys Res Commun 1990; 173: 816-822; Ciafaloni et al. Ann Neurol 1992; 31: 391-398). A 9-yr-old boy presenting with chronic asthma and depression was found to have abnormal mitochondria, partial defects of respiratory chain enzymes, and the MELAS point mutation.

Acid-Base Imbalance↗
PubMed1992

Induction by psychotropic drugs and local anesthetics of DnaK and GroEL proteins in Escherichia coli.

We examined effects of psychotropic drugs and local anesthetics on the synthesis of heat shock proteins in Escherichia coli. Chlorpromazine, a phenothiazine derivative, was shown to induce DnaK and GroEL proteins, major heat shock proteins in E. coli. The inductions of these proteins were not observed in an rpoH (= htpR) amber mutant strain, indicating that the heat shock sigma factor sigma 32 was required for their inductions. Northern blot hybridization analysis revealed that chlorpromazine induced increases of messenger RNAs for the DnaK and GroEL proteins. Thus, the induction occurred at the level of transcription. Chlorpromazine also induced non-heat shock proteins with molecular masses of 21 kDa, 20 kDa, and 17 kDa, even in the rpoH mutant strain. Other psychotropic drugs and local anesthetics, namely, dibucaine, lidocaine, imipramine, tetracaine and procaine, also induced DnaK and GroEL proteins and the small molecular weight proteins.

Anesthetics, Local↗
PubMed1992

Structural and functional mitochondrial abnormalities associated with high levels of partially deleted mitochondrial DNAs in somatic cell hybrids.

Kearns-Sayre syndrome (KSS) is a progressive and ultimately fatal human encephalomyopathy that is associated with large-scale deletions of mitochondrial DNA (mtDNA). To gain new insights into the developmental pathobiology of this disease, we studied the maintenance and expression of deleted mtDNAs (delta-mtDNAs) in somatic cell hybrids generated by fusion of HeLacot cells with a KSS fibroblast clone containing both wild-type and delta-mtDNAs. We observed that delta-mtDNAs were preferentially maintained over the KSS wild-type mtDNAs (wt-mtDNAs) in almost all isolated hybrid clones. Mitochondrial metabolism was not compromised in hybrids containing as much as 70-79% delta-mtDNAs. Two clones containing more than 99% delta-mtDNA were severely deficient in oxidative phosphorylation and exhibited abnormal, enlarged mitochondria. These clones had undetectable levels of mtDNA-encoded polypeptides, but contained normal amounts of a nuclear DNA-encoded mitochondrial protein. The data suggest a nonrandom pattern of mtDNA segregation in the triplasmic hybrids and a correlation among delta-mtDNA, structural mitochondrial abnormalities, and mitochondrial dysfunction.

Cell Division↗
PubMed1992

New morphological approaches to the study of mitochondrial encephalomyopathies.

Molecular genetics, biochemistry, immunology and morphology, are being applied in a coordinated fashion to unveil the molecular basis of the mitochondrial encephalomyopathies. Mutations of mitochondrial DNA (mtDNA) have been found in well characterized clinical groups of these disorders. New and old morphologic methods have been applied to investigate muscle biopsies from patients with mtDNA mutations. Important observations have been made on the cellular localization of normal and mutated mtDNA and on the expression of mtDNA-encoded polypeptides. These observations have provided insight into the pathogenesis of respiratory chain enzyme deficiency at the level of individual muscle fibers. Application of immunocytochemical and in situ hybridization techniques at the electron microscopic level will extend these studies to the level of individual mitochondria.

DNA, Mitochondrial↗
PubMed1992

Immunologic study of vinculin in Duchenne muscular dystrophy.

Using immunologic techniques, we studied vinculin, a cytoskeletal protein associated with the membrane-skeleton of the muscle fiber. We examined muscle biopsies from five patients with Duchenne muscular dystrophy (DMD), two with Becker's muscular dystrophy (BMD), three normal human muscle samples, and four biopsies from disease control patients. All DMD patients showed patchy and low-intensity immunostain at the sarcolemma of most fibers and, by immunoblot analysis, the content of vinculin was 42 to 61% of control values. There was no significant vinculin deficiency in samples from patients with BMD and other disease controls. The data suggest that vinculin content is reduced only in muscle where dystrophin is absent or sparse.

Adolescent↗
PubMed1992

Decrease by psychotropic drugs and local anaesthetics of membrane fluidity measured by fluorescence anisotropy in Escherichia coli.

The effects of psychotropic drugs and local anaesthetics on the fluidity of Escherichia coli cell membranes were examined. Chlorpromazine was shown to increase 1,6-diphenyl-1,3,5-hexatriene fluorescence anisotropy, indicating that it decreased the membrane fluidity. This increase was significant at a temperature of more than 24 degrees C. Dibucaine, lignocaine, imipramine, tetracaine and procaine also increased the fluorescence anisotropy.

Anesthetics, Local↗
PubMed1988

Coexisting adenocarcinoma and malignant lymphoma of the stomach: case report and review of the Japanese literature.

After a diagnosis of advanced carcinoma, a 77-yr-old female underwent gastrectomy. A 6 X 5 cm ulcerative mass in the angle was shown to be differentiated adenocarcinoma in the surrounding wall, and malignant lymphoma in the bottom. Carcinomatous infiltration was limited to the muscularis mucosae. Neither generalized lymphoma nor locoregional lymph node metastasis of either neoplasm was noted. A survey of 35 Japanese patients, including our own case with the two coexistent neoplasms in the stomach, revealed that the male-to-female ratio was 2.3:1, with no significant difference between the mean age of the sexes. The prevalence of adenocarcinoma in its early stage (60% of 35 patients) and of a histologically differentiated type (85% of 27 patients) of adenocarcinoma is quite different from that of usual Japanese gastric carcinoma, and it may suggest that there are some factors influencing the coexistent development of both neoplasms.

Adenocarcinoma↗
PubMed1986

A morphological study on the effects of collagen gel matrix on regeneration of severed rat sciatic nerve in silicone tubes.

The present study is a chronological morphological examination on the effects of collagen gel matrix on regeneration of severed sciatic nerves. The nerves (5 mm length) were resected, and both the distal and proximal stumps were inserted into a silicone tube with 5 mm gap in between. In the test side, the gap in the tube was then injected with liquid collagen which gels in the tissue when reconstructed with a certain buffer solution. The gap space in the tube of the control side was left empty. In a chronological examination of the tissue in the tube, considerably more rapid growth of sprouting axons toward the distal stump in the test side was revealed in comparison with the control side. The cells, including both fibroblasts and larger Schwann cells, were less in number. More orderly directions were observed in the collagen matrix than in the control tube. The result indicates that regeneration of the peripheral nerves in the silicone tube can be improved, by using appropriate exogenous fine materials, collagen matrix.

Animals↗
PubMed1986

Experimental study of WGA binding on the endothelial cell surface in cerebral ischemia.

The relationship between the saccharide chain on the endothelial cell surface and the permeability of intracerebral blood vessels has been studied. In the present study, wheat germ agglutinin (WGA) was perfused into capillaries in the area postrema of the normal Mongolian gerbil, where the blood brain barrier (BBB) is known to lack, and into intracerebral blood vessels, the BBB of which had been destroyed by experimentally induced brain ischemia. The light microscopic features of the sections from WGA-perfused brain tissues of the normal gerbil revealed that most of the blood vessels, including capillaries in the brain parenchyma, showed positive findings (the reaction induced a very distinct staining of the vascular wall) from which the course and structure of the fine vessels could be determined. The reaction to WGA on the diaphragma fenestra (DF) in capillaries in the area postrema was relatively weak, and DF without the reaction were occasionally revealed by electron microscopy. The gerbil, in which cerebral ischemia had been induced, also showed partial defect of the reaction with WGA on the luminal side of the endothelial cells. The results of the present experiment suggest some degree of correlation between the saccharide chains, including the specific monosaccharide of WGA, on the endothelial cell surface and permeability. It was considered that lectin can be used as an index for morphological observations, suggesting an alteration in function of the endothelial cell membrane. In addition, the perfusion method in this experiment suggested the possibility of distinguishing pinocytotic vesicles from pits of cell membranes.

Acetylglucosaminidase↗
PubMed1986

Lectin (UEA-1) reaction of capillary endothelium with reference to permeability in autopsied cases of cerebral infarction.

The relationship between endothelial reactivity to Ulex europaeus agglutinin-1 (UEA-1) and the permeability of the vascular wall in human autopsied cases of cerebral infarction was studied. Sections from the cerebral cortex were reacted with horseradish peroxidase UEA-1 to demonstrate the surface membrane of endothelial cells. Albumin in the neuropil of sections was demonstrated for the estimation of increased vascular permeability. The results showed that endothelial reactivity to UEA-1 was reduced in cases where death had occurred 3 to 5 days after onset of cerebral infarction. Reactivity was also diminished in cases where death had occurred after 13 and 25 days; these cases showed fresh ischemic lesions caused by re-attacks of infarction. Albumin extravasation into the neuropil was demonstrated in these intermediate cases. Chronic cases, dying after more than 52 days, showed no reduction of endothelial reactivity to UEA-1 and no albumin extravasation was proved. It was concluded that UEA-1 can be employed as a useful morphological marker for evaluation of endothelial function and vascular permeability.

Aged↗
PubMedDate not supplied

Histochemical study of human cremaster in varicocele patients.

Despite the cremaster's important role in thermoregulation, few morphological and biochemical studies of this muscle in humans have been reported, probably due to limitation of sampling. To gain further insight into the pathology of varicocele, the authors studied the histochemical changes of the cremaster from patients with varicocele. Cremaster was obtained from patients with male infertility and varicocele, grades 1-3. The samples were studied using routine histochemical stains. Fiber size variability and type I predominance were observed in all varicocele cases regardless of the grade, and also in control specimens. Muscle from patients with grades 2 and 3 varicocele showed small group atrophy. It would appear that the hemostasis associated with local tissue edema and hypoxemia may lead to nerve damage and denervation of the cremaster. If denervation of the cremaster persists despite the correction of varicocele, thermoregulation would remain disrupted.

Abdominal Muscles↗