PURPOSE: To provide quantitative data on the distribution of MyHCeom and compare the proportion of myosin heavy chain (MyHC) isoforms between the central and peripheral regions of human extraocular muscles (EOMs). METHODS: Medial rectus, lateral rectus, superior rectus, inferior rectus, superior oblique, and inferior oblique muscle samples were taken from three men with brain death. To examine the longitudinal distribution of myosin isoforms, the muscles were divided into central and peripheral portions of equal length. Electrophoresis and densitometry were used to quantify the distribution of MyHC isoforms. RESULTS: Electrophoresis of whole-muscle extracts of sampled EOMs revealed four MyHC bands that were identified as MyHCI, MyHCeom, MyHCIIa, and MyHCIIx. The proportion of MyHCeom was higher in the central region, whereas the proportion of MyHCIIa was higher in the peripheral region. The relative proportions of MyHCI, MyHCeom, and MyHCIIa were not significantly different among the EOMs. There was a tendency for higher levels of MyHCIIx in the inferior rectus muscle. CONCLUSIONS: The proportion of MyHCeom was higher in the central region of human EOMs. Further studies are needed to investigate the consequences of this distributional difference on the function of EOMs.
Brain Death ; Densitometry ; Electrophoresis ; Humans ; Male ; Muscles ; Myosin Heavy Chains ; Myosins ; Protein Isoforms

Medullomyoblastoma is a very rare central nervous system tumor and is regarded to be a variant of medulloblastoma showing a rhabdomyoblastic component. We found 32 cases of medullomyoblastoma in English literature. We recently experienced a case of a cerebellar medullomyoblastoma with neuronal differentiation in a 15-year-old girl who displayed headaches and vomiting. The tumor displayed extensive neuronal and myoblastic differentiation on microscopic and immunohistochemical examination. On ultrastructural study, the tumor obviously demonstrated rhabdomyoblastic features showing myofilaments composed of actin and myosin with well developed Z-bands.
Actins ; Adolescent ; Central Nervous System ; Female ; Headache ; Humans ; Medulloblastoma* ; Myoblasts ; Myofibrils ; Myosins ; Neurons* ; Vomiting

BACKGROUND: Osteopontin (OPN) is a cytokine associated with a cell-matrix via integrins. Fibroblast specific protein-1 (FSP-1), known as S100A4, has been implicated in cell migration by non-muscle myosin. We investigated whether the role of OPN and FSP-1/S100A4 expression in their contribution to the podocyte phenotype change to form podocyte bridge and cellular crescent. METHODS: Glomerular expression of OPN and FSP-1/S100A4 in renal biopsies of 16 patients with crescentic glomerulonephritis (CrGN) and 13 normal renal biopsies were studied by immunohistochemistry. RESULTS: The expression of OPN and FSP-1/S100A4 was increased in the podocytes of glomeruli, with and without crescents, in patients with CrGN. Neither OPN nor FSP-1/S100A4 was expressed in glomeruli from the normal controls (p<0.01). A significant positive correlation was found between the expression of OPN in glomerular tufts and cellular crescents, and the expression of OPN and FSP-1/S100A4 in glomerular tufts (p<0.05). CONCLUSIONS: The results suggest that OPN plays a role in early podocyte attachment to Bowman's capsule, and FSP-1/S100A4 potentiate podocyte contribution to cellular crescent formation by inducing cellular migration and growth.
Biopsy ; Bowman Capsule ; Cell Movement ; Fibroblasts ; Glomerulonephritis ; Humans ; Integrins ; Myosins ; Osteopontin ; Phenotype ; Podocytes

PURPOSE: Extraocular muscle (EOM) consists of two layers, the global and the orbital layer, which are readily distinguished by their histopathology. This study was conducted to investigate the changes of myosin heavy chain (MHC) and MHC isoforms of the global and the orbital layers of EOM after tenotomy. METHODS: Twenty four New Zealand white rabbits were used. The rectus muscles were harvested on day 3, week 1, week 2, week 3, week 4, and week 8 after EOM tenotomy. The change of MHC amount was measured using an electrophoresis. The changes of MHC isoforms were also measured quantitatively using western blot immunostaining. RESULTS: The amount of total MHC, fast MHC isoform, and slow MHC isoform decreased maximally at 1-week after EOM tenotomy and recovered at 4-week and 8-week after tenotomy. There was no significant change in the amount of the neonatal and developmental MHC isoform. CONCLUSIONS: Fast and slow MHC isoform changed mainly due to the changes in the global layer rather than in the orbital layer after EOM tenotomy.
Blotting, Western ; Electrophoresis ; Muscles ; Myosin Heavy Chains* ; Myosins* ; Orbit ; Protein Isoforms* ; Rabbits* ; Tenotomy*

PURPOSE: To study the changes in the amount and isoform pattern of the myosin heavy chain (MyHC) in rabbit extraocular muscle (EOM) fibers after recession. METHODS: Sixteen New Zealand white rabbits were used. Recession surgery was performed on the right superior rectus (SR) muscle by 3 mm in eight rabbits, and performed by 8 mm in other eight rabbits. The left SR muscles were left intact as the control groups. The SR muscles in both eyes were harvested from two rabbits from each recession group at 3 days and 1, 2, and 4 weeks after surgery. The changes in MyHC amount and isoform pattern were analyzed by gel electrophoresis. RESULTS: Total MyHC content decreased from 1 week after surgery in the 3-mm recessed group and from 3 days in the 8-mm group. The type IIb MyHC (MyHCIIb) plus EOM-specific MyHC (MyHCeom) showed similar proportional changes to the total MyHC at the different time points after surgery. CONCLUSIONS: The fast MyHCIIb plus the superfast MyHCeom decreased after EOM recession, and these results appear to be related to the changes in the global layer rather than in the orbital one. This suggests that the global layer might be the fast and the superfast twitch portions of rabbit EOM, which perform the fast saccades in ocular movements.
Electrophoresis ; Eye ; Muscles ; Myosin Heavy Chains ; Myosins ; Orbit ; Protein Isoforms ; Rabbits ; Saccades

PURPOSE: To study the changes in the amount and isoform pattern of the myosin heavy chain (MyHC) in rabbit extraocular muscle (EOM) fibers after recession. METHODS: Sixteen New Zealand white rabbits were used. Recession surgery was performed on the right superior rectus (SR) muscle by 3 mm in eight rabbits, and performed by 8 mm in other eight rabbits. The left SR muscles were left intact as the control groups. The SR muscles in both eyes were harvested from two rabbits from each recession group at 3 days and 1, 2, and 4 weeks after surgery. The changes in MyHC amount and isoform pattern were analyzed by gel electrophoresis. RESULTS: Total MyHC content decreased from 1 week after surgery in the 3-mm recessed group and from 3 days in the 8-mm group. The type IIb MyHC (MyHCIIb) plus EOM-specific MyHC (MyHCeom) showed similar proportional changes to the total MyHC at the different time points after surgery. CONCLUSIONS: The fast MyHCIIb plus the superfast MyHCeom decreased after EOM recession, and these results appear to be related to the changes in the global layer rather than in the orbital one. This suggests that the global layer might be the fast and the superfast twitch portions of rabbit EOM, which perform the fast saccades in ocular movements.
Electrophoresis ; Eye ; Muscles ; Myosin Heavy Chains ; Myosins ; Orbit ; Protein Isoforms ; Rabbits ; Saccades

Previously characterized as a backward motor, myosin VI (MYO6), which belongs to myosin family, moves toward the minus end of the actin track, a direction opposite to all other known myosin members. Recent researches have illuminated the role of MYO6 in human cancers, particularly in prostate cancer. However, the role of MYO6 in glioma has not yet been determined. In this study, to explore the role of MYO6 in human glioma, lentivirus-delivered short hairpin RNA (shRNA) targeting MYO6 was designed to stably down-regulate its endogenous expression in glioblastoma cells U251. Knockdown of MYO6 signifi cantly inhibited viability and proliferation of U251 cells in vitro. Moreover, the cell cycle of U251 cells was arrested at G0/G1 phase with the absence of MYO6, which could contribute to the suppression of cell proliferation. In conclusion, we firstly identified the crucial involvement of MYO6 in human glioma. The inhibition of MYO6 by shRNA might be a potential therapeutic method in human glioma.
Actins ; Cell Cycle ; Cell Proliferation ; Glioblastoma ; Glioma* ; Humans* ; Myosins* ; Prostatic Neoplasms ; RNA, Small Interfering

We evaluated the muscle fiber characteristics, the mean proportion of muscle fiber types and its range of individual difference in human vertebral muscle. Muscle samples used were from subjects who had a relatively brief history of spinal dysfunction such as compression fracture, disc hernia etc., and obtained from precisely defined superficial and deep sites on both sides of the vertebral column. In particular, samples were collected from three different levels of the column and flash-frozen sections of biopsied adult vertebral muscles were stained for H–E, trichrome, PAS, regular and reversed myosin ATPase, and SDH. Discrimination of muscle fiber types in H–E and trichrome stained sections was not evident. Three types of muscle fibers were, however, evident in PAS-stained sections according to the degree of positivity in observed vertebral muscles. The mean proportion of musele fiber types was different in regular and reversed myosin ATPase, and SDH stains and the majority of fiber types in human vertebral muscles was type I in three different levels of vertebral clumn. There was a decreasing tendency in percentage of type I fibers at both superficial and deep levels as the vertebral column descended. The size of muscle fibers was relatively larger in deep levels than in superficial levels of vertebral muscles. The human vertebral muscle showed moderately individual and regional differences in the mean size of fiber types. The evaluation for the combination patterns of various enzyme histochemical activities showed that the common musele fiber types(type I, II A and II B) were moderately reduced in the mean proportions and unusual rare muscle fiber types increased in number. And the decreasing tendency in the mean proportion of type as the vertebral column descended was not evident in the combination patterns of histochemical activities
Adult ; Coloring Agents ; Discrimination (Psychology) ; Fractures, Compression ; Hernia ; Humans ; Individuality ; Muscles ; Myosins ; Spine

There have been numerous hypotheses about the pathogenesis of idiopathic scoliosis, but it is still unclear. There are some reports that abnormalities of contractile proteins may play a role in the pathogenesis of idiopathic scoliosis. The purpose of this report is to study the quantitative abnormalities of contractile proteins in muscles and nonactivated and activated platelets, and to determine whether or not the abnormalities in contractile proteins may play a role in the pathogenesis of idiopathic scoliosis. The materials were 21 idiopathic scoliosis patients aged from 13 years to 28 years(average 19.2 years) and 20 persons aged from 17 years to 25 years(average 20.1 years) as a control group. The electrophoretic analysis(SDS-PAGE method) was done on platelets both unstimulated and stimulated with thrombin and also on proteins of paraspinal muscles and gluteus maximus of idiopathic scoliosis patient and paraspinal muscles of control group. The results are as follows. 1. The myosin/actin ratios of triton-insoluble fractions to paraspinal muscles in convex sides of main curvatures of scoliosis patients(1.69±0.81) were significantly decreased compared to those of concave sides(2.55±1.28), gluteus maximus muscles(2.56±1.70) and control group(2.61±1.01). 2. There were no significant differences between scoliosis group and control group in the actin/myosin ratios of triton-insoluble fractions of the platelets both nonactivated and activated by thrombin. In conclusion, abnormalities of contractile protein in paraspinal muscles of convex side may play a role in the pathogenesis of idiopathic scoliosis, rather than abnormalities of systemic contractile protein.
Actins ; Blood Platelets ; Contractile Proteins ; Humans ; Muscles ; Myosins ; Paraspinal Muscles ; Scoliosis ; Thrombin

May-Hegglin anomaly (MHA) is an autosomal dominant disorder characterized by macrothrombocytopenia and leukocyte inclusions. In 1992, we reported the first Korean case of MHA family. Again, in this family, we identified a nonsense C5797T mutation (R1933X) in the MYH9 gene, encoding non-muscle myosin heavy chain A. To the best of our knowledge, our genetic study in this MHA family is the first report of mutation resulting in the truncation of 28 of 34 amino acids of the carboxy-terminal tailpiece of the myosin heavy chain in Korea.
Amino Acids ; Humans ; Inclusion Bodies ; Korea ; Leukocytes ; Myosin Heavy Chains ; Myosins