Table of Contents
Articles
5' Azacytine enhances exogenous
gene expression in skeletal muscle
Maria Grazia D'Angelo, Carlo
Ausenda, Yvan Torrente, Andreina Bordoni, Stefania Corti, Maria
Paola Perini,
Monica Colucci, Giacomo P. Comi, Nereo Bresolin and
Guglielmo Scarlato
[Full
text pdf 829Kb]
Study of the
Electrically Evoked EMG and Torque Output during the Muscle
Fatigue Process in FES-Induced Static
and Dynamic
Contractions
Nan-Ying Yu, Jia-Jin J. Chen and Ming-Shaung Ju
[Full text
pdf 109Kb]
Changes in the
Sinthesis of Total Proteins Induced by Chronic Stimulation of
Skeletal Muscle
Bernadette Cummins and Stanley
Salmons [Full
text pdf 103Kb]
Rat cardiomyocytes with
TUNEL-positive nuclei induced by permanent ischemia show
increased plasma-membrane
permeability (PMP) -
monitored by a combined use of TUNEL method
and lanthanum ions
Tong Jie, Hiroshi Ikeda, Uta Hashizume, Chao Long
Yong, Tomohiro Takeo, Haruchi Nishimaki,
Kenji Masuda and Gen Itoh [Full
text pdf 359Kb]
Myo-News Content of BAM 8 (1-6),
1998; Author Index; Subject index; Acknowledgements; Information
for Authors
5’ Azacytidine Enhances Exogenous Gene Expression in Skeletal Muscle
Maria G. D’Angelo, Carlo Ausenda, Yvan Torrente, Andreina Bordoni, Stefania Corti, Roberto Del Bo(1), Maria P. Perini, Monica Colucci(1), Giacomo P. Comi, Nereo Bresolin, Guglielmo Scarlato
Institute of Clinical Neurology, Dino Ferrari Center, University of Milan, IRCCS Ospedale Maggiore Policlinico and (1) IRCCS Eugenio Medea, Bosisio Parini, Italy
Abstract
DNA methylation is one of the mechanism for regulating gene expression. Transfected cells in tissue culture are a mosaic of expression of the exogenous gene. 5’ azacytidine (Aza C), inhibiting nuclear DNA methyltransferase, causes an increase of expression of a-galactosidas (LacZ) in transfected CHO cells.
Murine muscle cell lines G8 and C2C12 were transfected by biolistic technique with plasmids carrying a reporter gene pCMVlacZ and pY3 that confers resistance to Hygromycin B. Resistant clones have been treated with different concentrations of 5’ azacytidine and analyzed by X-gal stain and Southern Blotting of DNA, after various time intervals up to one month. Hygromycin resistant cells were transplanted in the tibialis anterior muscle of living mice. Aza C was injected subcutaneously above the treated muscle. Histochemistry with X-gal was performed after different treatment periods, in order to evaluate the reporter gene expression timings.
The myogenic cell lines, after treatment with 5’ azacytidine in vitro, express the exogenous gene at different levels, with four fold enhancement in G8 cells, after 15 days from transfection. The enhancement of expression is directly derived from the inhibition of methylation as shown by DNA restriction analysis. Mouse muscular samples treated sub-cutaneously with 5’ azacytidine showed an enhancement of lacZ expression in vivo up to 20 days after transfection.
5’ azacytidine enhances the level and the time span of exogenous
gene expression in muscle cells facilitating gene therapy studies.
Key words: 5’ azacytidine, myogenic cell, methylation, gene
expression, in vivo treatment. Basic Appl. Myol. 9 ( ): x,
1999
Address correspondence to:
Dott. Maria Grazia D’Angelo, Istituto di Clinica Neurologica, Ospedale Maggiore Policlinico, Via F. Sforza 35, 20122 Milano, Italy, phone 0039 2 55033817, fax 0039 2 55190392, Email gpcomi@imiucca.csi.unimi.it.
Study of the Electrically Evoked EMG and Torque Output During the Muscle Fatigue Process in FES-Induced Static and Dynamic Contractions
Nan-Ying Yu(1,3), Jia-Jin J. Chen(1), Ming-Shaung Ju(2)
(1) Institute of Biomedical Engineering, (2) Department of
Mechanical Engineering, National Cheng Kung University, Tainan,
Taiwan, R.O.C. and (3) Department of Rehabilitation Medicine,
Foo-Yin Institute of Technology
Abstract
This study compared the different fatigue processes of
electrically elicited static and dynamic muscle contractions of
quadriceps in five paraplegic subjects. An electrodynamometer was
utilized for recording the generated torque output and controlling
the isokinetic dynamic movements. Stimulus-evoked electromyography
(EMG), after artifact suppression, was used to observe the fatigue
process. Besides torque output, the measured EMG features included
peak to peak amplitude, rise time to peak and peak to peak
duration. The measurements were modeled by a hyperbolic tangent
function, which allowed observance of their time constants,
inflection times and relative residual levels during the fatigue
process. The time constants as well as the inflection time of
torque output and EMG features were compared between static and
dynamic contractions. The inflection times of torque output and
all EMG features measured during static contraction were found
larger than those of dynamic contraction. In EMG temporal
features, the inflection times of rise time to peak and peak to
peak duration in static contractions were also found significantly
larger than those of dynamic contractions. These conditions
indicated that, from either contractile (torque curves) or
excitation (EMG features) aspects, the electrically elicited
muscle contraction in dynamic movement is prone to fatigue earlier
and faster.
Key words: electromyography, functional electrical
stimulation, muscle fatigue, paraplegia. Basic Appl. Myol. 9 (1):
x, 1999
Address correspondence to:
Nan-Ying Yu, Institute of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan, 70101, R.O.C., phone 886 6 2757575 63423, fax 886 6 2343270, Email ying@jason.bme.ncku.edu.tw.
Changes in the Synthesis of Total Proteins Induced by Chronic Electrical Stimulation of Skeletal Muscle
Bernadette Cummins(1) and Stanley Salmons(2)
(1) Department of Anatomy, University of Birmingham, Edgbaston,
Birmingham, and (2) Department of Human Anatomy
and Cell Biology, University of Liverpool, Liverpool, UK
Abstract
Rates of protein synthesis were measured by constant infusion of 3H-tyrosine, in control fast and slow muscles of the rabbit hind limb, and in fast muscles subjected to chronic electrical stimulation.
Slow muscle had synthesis rates more than twice those of fast muscle, and its RNA content was 20% higher.
Stimulation of fast muscle brought about a striking phasic increase, lasting several weeks, in protein synthetic rates, RNA content and RNA activity. There was indirect evidence for an accompanying increase in the rate of protein degradation. In the long term, synthesis rates stabilized at levels similar to those found in slow muscle.
These results provide evidence of an overall increase in protein
turnover that is significant in relation to both experimental and
therapeutic applications of chronic electrical stimulation.
Key words: chronic stimulation, muscle, RNA, protein
synthesis. Basic Appl. Myol. 9 (1): x, 1999
Address correspondence to:
Professor S. Salmons, Department of Human Anatomy and Cell Biology, University of Liverpool, The New Medical School, Ashton Street, Liverpool L69 3GE, UK, E-mail s.salmons@liverpool.ac.uk.
Rat Cardiomyocytes with TUNEL-Positive Nuclei Induced by Permanent Ischemia Show Increased Plasma-Membrane Permeability (PMP) - Monitored by a Combined Use of TUNEL Method and Lanthanum Ions -
Tong Jie, Hiroshi Ikeda, Uta Hashizume, Chao Long Yong, Tomohiro Takeo, Haruki Nishimaki, Kenji Masuda and Gen ItFirst Department of Pathology, Aichi Medical University
Abstracts
The aim of this study was to clarify whether myocardial cells with DNA fragmentation induced by ischemia show increased plasma-membrane permeability (PMP), focusing on the early lesions of acute myocardial ischemia (AMI). Rat AMI was induced by a permanent occlusion of the left coronary artery. The TUNEL method was used for the demonstration of DNA fragmentation, and lanthanum ions (La) were employed for the increased PMP of cardiomyocytes. The increased PMP of cardiomyocytes having TUNEL-positive nuclei was determined by a combined use of the TUNEL method in frozen sections and electron microscopic identification of intracellular depositions of La.
Seven of 10 cardiomyocytes having TUNEL-positive nuclei revealed the deposition of La 2 hours after ischemia, and 10 of 13 showed La deposition 3 hours after ischemia. Almost all cardiomyocytes labeled with TUNEL stain showed intracellular deposition of La 4 and 6 hours after ischemia, respectively.
The evidence obtained from this experiment demonstrates that
almost all cardiomyocytes labeled with TUNEL stain simultaneously
show an increase of PMP in the AMI foci. In conclusion, the
mechanism of myocardial cell death caused by permanent ischemia is
due to a mixed form of apoptosis and necrosis.
Key words: rat myocardial ischemia, TUNEL method,
apoptosis, DNA fragmentation, lanthanum ions. Basic Appl. Myol. 9
(1): x, 1999
Address correspondence to:
Gen Itoh M.D., Ph.D., First Department of Pathology, Aichi Medical University, 21 Karimata Nagakute-cho, Aichi-gun, Aichi-ken 480-1195, Japan.
