Enhancing Interrogation of Skeletal Muscle Samples for Informative Quantitative Data

Journal of Neuromuscular Diseases ◽

10.3233/jnd-210736 ◽

2021 ◽

pp. 1-13

Author(s):

Terence A. Partridge

Keyword(s):

Skeletal Muscle ◽

Homo Sapiens ◽

Practical Importance ◽

Analytical Techniques ◽

Sampling Bias ◽

Preclinical Research ◽

Muscle Sample ◽

Accurate Picture ◽

Research Findings ◽

Accurate Comparison

Careful quantitative analysis of histological preparations of muscle samples is crucial to accurate investigation of myopathies in man and of interpretation of data from animals subjected to experimental or potentially therapeutic treatments. Protocols for measuring cell numbers are subject to problems arising from biases associated with preparative and analytical techniques. Prominent among these is the effect of polarized structure of skeletal muscle on sampling bias. It is also common in this tissue to collect data as ratios to convenient reference dominators, the fundamental bases of which are ill-defined, or unrecognized or not accurately assessable. Use of such ‘floating’ denominators raises a barrier to estimation of the absolute values that assume practical importance in medical research, where accurate comparison between different scenarios in different species is essential to the aim of translating preclinical research findings in animal models to clinical utility in Homo sapiens. This review identifies some of the underappreciated problems with current morphometric practice, some of which are exacerbated in skeletal muscle, and evaluates the extent of their intrusiveness into the of building an objective, accurate, picture of the structure of the muscle sample. It also contains recommendations for eliminating or at least minimizing these problems. Principal among these, would be the use of stereological procedures to avoid the substantial counting biases arising from inter-procedure differences in object size and section thickness. Attention is also drawn to the distortions of interpretation arising from use of undefined or inappropriate denominators.

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Criminal Law Protection of Reproductive Health: Current Challenges

Economics taxes & law ◽

10.26794/1999-849x-2019-12-2-147-153 ◽

2019 ◽

Vol 12 (2) ◽

pp. 147-153

Author(s):

E. L. Sidorenko

Keyword(s):

Reproductive Health ◽

Human Genome ◽

Criminal Law ◽

Policy Development ◽

Practical Importance ◽

Criminal Policy ◽

Criminal Code ◽

Research Findings ◽

The Individual ◽

Criminal Legislation

The subject of the research is the specifics of the criminal law protection of reproductive health in the Russian legislation. The topic was chosen due to the increasing dynamics of crimes related to limitation on the reproductive rights of women and men and unauthorized manipulation of the human genome. Despite the growing need for providing a regulatory framework for this kind of relationships, the system of their criminal law protection is only beginning to take shape, therefore, a necessity arises to revise traditional approaches to the protection of the individual. Therefore, the purpose of the paper was to understand the system of criminal law protection of reproductive health in terms of its compliance with trends of medical practices and dynamics of socially significant diseases based on both traditional principles of scientific analysis and the results of applying sociological methods of data processing, which made it possible to identify the most significant directions of the Russian criminal policy development. Moreover, the critical analysis method was used in the research that showed the inconsistency of the system of criminal law prevention of criminal abortions, contamination with socially significant diseases and illegal use of the human genome. Based on the research findings, an author’s model of criminal prevention of attacks on reproductive health has been built and its systemic assessment is given. It is concluded that the legislator is inconsistent in assessing the attributes of an unlawful abortion; the accounting of contamination with certain socially significant diseases is inadequate; the laws prohibiting the use of the human genome need to be included into the Criminal Code of the Russian Federation. The conclusions formulated in the paper have practical importance and can be taken into account by the legislator in the reform of the current criminal legislation.

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Sarcomere length operating range of vertebrate muscles during movement

Journal of Experimental Biology ◽

10.1242/jeb.204.9.1529 ◽

2001 ◽

Vol 204 (9) ◽

pp. 1529-1536 ◽

Cited By ~ 20

Author(s):

T.J. Burkholder ◽

R.L. Lieber

Keyword(s):

Skeletal Muscle ◽

Sarcomere Length ◽

Narrow Range ◽

Analytical Techniques ◽

Operating Range ◽

Physiological Importance ◽

Rigor State ◽

Secondary Purpose ◽

Length Measurements ◽

Length Changes

The force generated by skeletal muscle varies with sarcomere length and velocity. An understanding of the sarcomere length changes that occur during movement provides insights into the physiological importance of this relationship and may provide insights into the design of certain muscle/joint combinations. The purpose of this review is to summarize and analyze the available literature regarding published sarcomere length operating ranges reported for various species. Our secondary purpose is to apply analytical techniques to determine whether generalizations can be made regarding the “normal” sarcomere length operating range of skeletal muscle. The analysis suggests that many muscles operate over a narrow range of sarcomere lengths, covering 94+/−13 % of optimal sarcomere length. Sarcomere length measurements are found to be systematically influenced by the rigor state and methods used to make these measurements.

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Quantitative study of motor endplates in muscle fibres dissociated by a simple procedure

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1980.0112 ◽

1980 ◽

Vol 209 (1177) ◽

pp. 555-562 ◽

Cited By ~ 7

Keyword(s):

Skeletal Muscle ◽

Binding Sites ◽

Simple Procedure ◽

Muscle Fibres ◽

Single Muscle ◽

Muscle Sample ◽

Motor Endplates ◽

Large Numbers ◽

Muscle Types ◽

Receptor Number

Large numbers of single muscle fibres can be obtained reproducibly from glutaraldehyde-fixed skeletal muscle by the method described here. With suitable modifications, one can estimate acetylcholine receptor number (α-bungarotoxin binding sites) and endplate area in parallel portions produced from the same muscle sample, so that small differences (e. g. with growth or between muscle types) become detectable. Micro-dissection further increases the precision of evaluation of junctional, perijunctional and extrajunctional binding sites. Other applications are illustrated.

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Explaining and Controlling Regression to the Mean in Longitudinal Research Designs

Journal of Speech Language and Hearing Research ◽

10.1044/1092-4388(2003/104) ◽

2003 ◽

Vol 46 (6) ◽

pp. 1340-1351 ◽

Cited By ~ 26

Author(s):

Xuyang Zhang ◽

J. Bruce Tomblin

Keyword(s):

Measurement Error ◽

Longitudinal Research ◽

Formal Analysis ◽

Sampling Bias ◽

Regression To The Mean ◽

Regression Effects ◽

Regression Effect ◽

Research Designs ◽

Research Findings ◽

The Mean

This tutorial is concerned with examining how regression to the mean influences research findings in longitudinal studies of clinical populations. In such studies participants are often obtained because of performance that deviates systematically from the population mean and are then subsequently studied with respect to change in the trait used for this selection. It is shown that in such research there is a potential for the estimates of change to be erroneous due to the effect of regression to the mean. The source of the regression effect is shown to arise from measurement error and a sampling bias of this measurement error in the process of selecting on extreme scores. It is also shown that regression effects are greater with measures that are less reliable and with samples that are selected with more extreme scores. Furthermore, it is shown that regression effects are particularly prominent when measures of change are based on changes in dichotomous states formed from quantitative, normally distributed traits. In addition to a formal analysis of the regression to the mean, the features of regression to the mean are demonstrated via a simulation.

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Glucose infusion causes insulin resistance in skeletal muscle of rats without changes in Akt and AS160 phosphorylation

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00133.2007 ◽

2007 ◽

Vol 293 (5) ◽

pp. E1358-E1364 ◽

Cited By ~ 34

Author(s):

Andrew J. Hoy ◽

Clinton R. Bruce ◽

Anna Cederberg ◽

Nigel Turner ◽

David E. James ◽

...

Keyword(s):

Insulin Resistance ◽

Skeletal Muscle ◽

Glucose Uptake ◽

Insulin Signaling ◽

Glycogen Synthase ◽

Glycogen Synthesis ◽

Glucose Infusion ◽

Metabolic Effects ◽

Synthesis Rate ◽

Muscle Sample

Hyperglycemia is a defining feature of Type 1 and 2 diabetes. Hyperglycemia also causes insulin resistance, and our group (Kraegen EW, Saha AK, Preston E, Wilks D, Hoy AJ, Cooney GJ, Ruderman NB. Am J Physiol Endocrinol Metab Endocrinol Metab 290: E471–E479, 2006) has recently demonstrated that hyperglycemia generated by glucose infusion results in insulin resistance after 5 h but not after 3 h. The aim of this study was to investigate possible mechanism(s) by which glucose infusion causes insulin resistance in skeletal muscle and in particular to examine whether this was associated with changes in insulin signaling. Hyperglycemia (∼10 mM) was produced in cannulated male Wistar rats for up to 5 h. The glucose infusion rate required to maintain this hyperglycemia progressively lessened over 5 h (by 25%, P < 0.0001 at 5 h) without any alteration in plasma insulin levels consistent with the development of insulin resistance. Muscle glucose uptake in vivo (44%; P < 0.05) and glycogen synthesis rate (52%; P < 0.001) were reduced after 5 h compared with after 3 h of infusion. Despite these changes, there was no decrease in the phosphorylation state of multiple insulin signaling intermediates [insulin receptor, Akt, AS160 (Akt substrate of 160 kDa), glycogen synthase kinase-3β] over the same time course. In isolated soleus strips taken from control or 1- or 5-h glucose-infused animals, insulin-stimulated 2-deoxyglucose transport was similar, but glycogen synthesis was significantly reduced in the 5-h muscle sample (68% vs. 1-h sample; P < 0.001). These results suggest that the reduced muscle glucose uptake in rats after 5 h of acute hyperglycemia is due more to the metabolic effects of excess glycogen storage than to a defect in insulin signaling or glucose transport.

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Genetic Markers Associated with Power Athlete Status

Journal of Human Kinetics ◽

10.2478/hukin-2019-0053 ◽

2019 ◽

Vol 68 (1) ◽

pp. 17-36 ◽

Cited By ~ 4

Author(s):

Agnieszka Maciejewska-Skrendo ◽

Paweł Cięszczyk ◽

Jakub Chycki ◽

Marek Sawczuk ◽

Wojciech Smółka

Keyword(s):

Skeletal Muscle ◽

Genetic Markers ◽

Athletic Performance ◽

Great Influence ◽

Pressure Control ◽

Psychological Traits ◽

Endurance Strength ◽

Research Findings ◽

And Function ◽

Genetic Profiles

AbstractAthletic performance is a multifactorial phenotype influenced by environmental factors as well as multiple genetic variants. Different genetic elements have a great influence over components of athletic performance such as endurance, strength, power, flexibility, neuromuscular coordination, psychological traits and other features important in sport. The current literature review revealed that to date more than 69 genetic markers have been associated with power athlete status. For the purpose of the present review we have assigned all genetic markers described with reference to power athletes status to seven main groups: 1) markers associated with skeletal muscle structure and function, 2) markers involved in the inflammatory and repair reactions in skeletal muscle during and after exercise, 3) markers involved in blood pressure control, 4) markers involved in modulation of oxygen uptake, 5) markers that are regulators of energy metabolism and cellular homeostasis, 6) markers encoding factors that control gene expression by rearrangement of chromatin fibers and mRNA stability, and 7) markers modulating cellular signaling pathways. All data presented in the current review provide evidence to support the notion that human physical performance may be influenced by genetic profiles, especially in power sports. The current studies still represent only the first steps towards a better understanding of the genetic factors that influence power-related traits, so further analyses are necessary before implementation of research findings into practice.

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Lost in Translation - Bridging the preclinical and clinical worlds concepts, Examples, Successes, and Failures in Translational Medicine

10.31219/osf.io/ujzwe ◽

2019 ◽

Author(s):

Attila A Seyhan

Keyword(s):

Drug Development ◽

Biomedical Research ◽

Development Process ◽

Public Funding ◽

Human Studies ◽

Attrition Rate ◽

Drug Development Process ◽

Preclinical Research ◽

Attrition Rates ◽

Research Findings

The biopharmaceutical companies involved in developing drugs for human diseases are facing considerable challenges, both politically and fiscally. There is growing pressure from the general public, funding agencies, and the policymakers for scientists and industry to improve drug development process, better bridge basic and translational human studies, and ultimately improve the process of the development of more effective, safer, and less costly drugs.The crisis involving the scale of the reproducibility and translatability of preclinical research to human studies and high attrition rate of drug development process is widely recognized both in academia and industry. Despite all this, the high attrition rates of drug development and the magnitude of the reproducibility and translatability problems with the preclinical research findings to human studies remain a fact.Recent reports in literature also suggest that many published research findings in preclinical research are misleading, not as robust as they claim, or cannot be reproduced and hence cannot be translated to human studies. The reasons are complex and challenging. Potential culprits range from the complexity of modern biomedical research to the limitations of tools, the trivial methodological differences, to poor experimental designs, inappropriate data analysis, misuse of statistics, the poor predictability of animal results in humans, as well as training and perverse incentives in academia.There are many reports suggesting solutions to overcome these roadblocks in biomedical research. However, how scientists, researchers, and the biopharmaceutical industry deal with this problem depends on the understanding of the root causes of the problem and the strategies and approaches to solving this problem to improve biomedical research.The purpose of this article is to conduct a thorough literature review to evaluate the nature of some of the problems leading to high attrition rates of drug development and to provide some suggestion to overcome the obstacles that impede the drug development process.

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Antisense oligonucleotides targeting angiotensinogen: insights from animal studies

Bioscience Reports ◽

10.1042/bsr20180201 ◽

2019 ◽

Vol 39 (1) ◽

Cited By ~ 3

Author(s):

Chia-Hua Wu ◽

Ya Wang ◽

Murong Ma ◽

Adam E. Mullick ◽

Rosanne M. Crooke ◽

...

Keyword(s):

Antisense Oligonucleotides ◽

Therapeutic Approach ◽

Animal Studies ◽

Preclinical Research ◽

Angiotensin Peptides ◽

Research Findings

Abstract Angiotensinogen (AGT) is the unique substrate of all angiotensin peptides. We review the recent preclinical research of AGT antisense oligonucleotides (ASOs), a rapidly evolving therapeutic approach. The scope of the research findings not only opens doors for potentially new therapeutics of hypertension and many other diseases, but also provides insights into understanding critical physiological and pathophysiological roles mediated by AGT.

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Cardiac troponin-I is not expressed in fetal and healthy or diseased adult human skeletal muscle tissue

Clinical Chemistry ◽

10.1093/clinchem/41.12.1710 ◽

1995 ◽

Vol 41 (12) ◽

pp. 1710-1715 ◽

Cited By ~ 196

Author(s):

G S Bodor ◽

D Porterfield ◽

E M Voss ◽

S Smith ◽

F S Apple

Keyword(s):

Skeletal Muscle ◽

Cardiac Troponin ◽

Human Skeletal Muscle ◽

Troponin I ◽

Tissue Bank ◽

Cardiac Troponin I ◽

Muscle Disease ◽

Adult Skeletal Muscle ◽

Muscle Sample ◽

Creatine Kinase Mb

Abstract Cardiac troponin-I (cTnI) is not found in sera of patients with skeletal muscle disease in the absence of myocardial injury. It is not known, however, whether trace amounts of cTnI are expressed in regenerating human skeletal muscle, as has been observed with creatine kinase MB. Using immunohistochemical and biochemical techniques, we investigated cTnI expression in various human muscle tissues: human heart tissue (n = 5), normal adult skeletal muscle (n = 3), and fetal heart (n = 3) and skeletal muscle (n = 3) obtained, respectively, during heart transplant, from autopsy, or from a tissue bank. Specimens from diagnostic tissue biopsies were used as diseased skeletal muscle: polymyositis (PM), n = 13; Duchenne muscular dystrophy (DMD), n = 6. Frozen sections 8 microns thick were stained immunohistochemically for either cTnI or TnI (cardiac or skeletal) by using monoclonal antibodies (MAb) 2B1.9 (cTnI specific) or 3C5.10 (reactive with all TnI isoforms), respectively. cTnI was measured in tissue homogenates by an immunofluorometric assay. Cardiac muscle was stained by both MAbs. Normal fetal and adult skeletal muscle, and samples from all of the PM and DMD patients, stained only with the nonspecific MAb (3C5.10), confirming the sole presence of skeletal TnI. No cTnI was detectable by immunoassay in any skeletal muscle sample. We conclude that cTnI is not expressed in human skeletal muscle during development or during regenerative muscle disease processes such as PM or DMD.

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