A species of newt in the Salamandridae family in which the larvae transform into terrestrial eft stage and later into an aquatic adult. They occur from Canada to southern United States. Viridescens refers to the greenish color often found in this species.

A family of Urodela consisting of 15 living genera and about 42 species and occurring in North America, Europe, Asia, and North Africa.

The physiological renewal, repair, or replacement of tissue.

The farthest or outermost projections of the body, such as the HAND and FOOT.

A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.

Elongated, spindle-shaped, quiescent myoblasts lying in close contact with adult skeletal muscle. They are thought to play a role in muscle repair and regeneration.

Developmental events leading to the formation of adult muscular system, which includes differentiation of the various types of muscle cell precursors, migration of myoblasts, activation of myogenesis and development of muscle anchorage.

A genus of aquatic newts in the Salamandridae family. During breeding season many Triturus males have a dorsal crest which also serves as an accessory respiratory organ. One of the common Triturus species is Triturus cristatus (crested newt).

Contractile tissue that produces movement in animals.

Agents that have a damaging effect on the HEART. Such damage can occur from ALKYLATING AGENTS; FREE RADICALS; or metabolites from OXIDATIVE STRESS and in some cases is countered by CARDIOTONIC AGENTS. Induction of LONG QT SYNDROME or TORSADES DE POINTES has been the reason for viewing some drugs as cardiotoxins.

Embryonic (precursor) cells of the myogenic lineage that develop from the MESODERM. They undergo proliferation, migrate to their various sites, and then differentiate into the appropriate form of myocytes (MYOCYTES, SKELETAL; MYOCYTES, CARDIAC; MYOCYTES, SMOOTH MUSCLE).

Most abundant proteins in COBRA venom; basic polypeptides of 57 to 62 amino acids with four disulfide bonds and a molecular weight of less than 7000; causes skeletal and cardiac muscle contraction, interferes with neuromuscular and ganglionic transmission, depolarizes nerve, muscle and blood cell membranes, thus causing hemolysis.

Large, multinucleate single cells, either cylindrical or prismatic in shape, that form the basic unit of SKELETAL MUSCLE. They consist of MYOFIBRILS enclosed within and attached to the SARCOLEMMA. They are derived from the fusion of skeletal myoblasts (MYOBLASTS, SKELETAL) into a syncytium, followed by differentiation.

A salamander found in Mexican mountain lakes and accounting for about 30 percent of the urodeles used in research. The axolotl remains in larval form throughout its life, a phenomenon known as neoteny.

Distinct regions of mesenchymal outgrowth at both flanks of an embryo during the SOMITE period. Limb buds, covered by ECTODERM, give rise to forelimb, hindlimb, and eventual functional limb structures. Limb bud cultures are used to study CELL DIFFERENTIATION; ORGANOGENESIS; and MORPHOGENESIS.

Precursor cells destined to differentiate into skeletal myocytes (MYOCYTES, SKELETAL).

A myogenic regulatory factor that controls myogenesis. Though it is not clear how its function differs from the other myogenic regulatory factors, MyoD appears to be related to fusion and terminal differentiation of the muscle cell.

Renewal or physiological repair of damaged nerve tissue.

A paired box transcription factor that is involved in EMBRYONIC DEVELOPMENT of the CENTRAL NERVOUS SYSTEM and SKELETAL MUSCLE.

The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.

A strain of mice arising from a spontaneous MUTATION (mdx) in inbred C57BL mice. This mutation is X chromosome-linked and produces viable homozygous animals that lack the muscle protein DYSTROPHIN, have high serum levels of muscle ENZYMES, and possess histological lesions similar to human MUSCULAR DYSTROPHY. The histological features, linkage, and map position of mdx make these mice a worthy animal model of DUCHENNE MUSCULAR DYSTROPHY.

Repair or renewal of hepatic tissue.

Either of two extremities of four-footed non-primate land animals. It usually consists of a FEMUR; TIBIA; and FIBULA; tarsals; METATARSALS; and TOES. (From Storer et al., General Zoology, 6th ed, p73)

A front limb of a quadruped. (The Random House College Dictionary, 1980)

Acquired, familial, and congenital disorders of SKELETAL MUSCLE and SMOOTH MUSCLE.

Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.

A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.

A genus of the Ambystomatidae family. The best known species are the axolotl AMBYSTOMA MEXICANUM and the closely related tiger salamander Ambystoma tigrinum. They may retain gills and remain aquatic without developing all of the adult characteristics. However, under proper changes in the environment they metamorphose.

A myogenic regulatory factor that controls myogenesis. Myogenin is induced during differentiation of every skeletal muscle cell line that has been investigated, in contrast to the other myogenic regulatory factors that only appear in certain cell types.

A class of free-living freshwater flatworms of North America.

Nonparasitic free-living flatworms of the class Turbellaria. The most common genera are Dugesia, formerly Planaria, which lives in water, and Bipalium, which lives on land. Geoplana occurs in South America and California.

Muscular Dystrophy, Animal: A group of genetic disorders causing progressive skeletal muscle weakness and degeneration, characterized by the lack of or defective dystrophin protein, which can also affect other organ systems such as heart and brain, occurring in various forms with different degrees of severity and age of onset, like Duchenne, Becker, Myotonic, Limb-Girdle, and Facioscapulohumeral types, among others.

Membranous appendage of fish and other aquatic organisms used for locomotion or balance.

An order of the Amphibia class which includes salamanders and newts. They are characterized by usually having slim bodies and tails, four limbs of about equal size (except in Sirenidae), and a reduction in skull bones.

A SKELETAL MUSCLE-specific transcription factor that contains a basic HELIX-LOOP-HELIX MOTIF. It plays an essential role in MUSCLE DEVELOPMENT.

Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)

Skeletal muscle fibers characterized by their expression of the Type I MYOSIN HEAVY CHAIN isoforms which have low ATPase activity and effect several other functional properties - shortening velocity, power output, rate of tension redevelopment.

Skeletal muscle fibers characterized by their expression of the Type II MYOSIN HEAVY CHAIN isoforms which have high ATPase activity and effect several other functional properties - shortening velocity, power output, rate of tension redevelopment. Several fast types have been identified.

Recording of the changes in electric potential of muscle by means of surface or needle electrodes.

Derangement in size and number of muscle fibers occurring with aging, reduction in blood supply, or following immobilization, prolonged weightlessness, malnutrition, and particularly in denervation.

In anatomical terms, "tail" is not used as a medical definition to describe any part of the human body; it is however used in veterinary medicine to refer to the distal portion of the spine in animals possessing tails.

Inbred C57BL mice are a strain of laboratory mice that have been produced by many generations of brother-sister matings, resulting in a high degree of genetic uniformity and homozygosity, making them widely used for biomedical research, including studies on genetics, immunology, cancer, and neuroscience.

Relatively undifferentiated cells that retain the ability to divide and proliferate throughout postnatal life to provide progenitor cells that can differentiate into specialized cells.

A heterogeneous group of inherited MYOPATHIES, characterized by wasting and weakness of the SKELETAL MUSCLE. They are categorized by the sites of MUSCLE WEAKNESS; AGE OF ONSET; and INHERITANCE PATTERNS.

An X-linked recessive muscle disease caused by an inability to synthesize DYSTROPHIN, which is involved with maintaining the integrity of the sarcolemma. Muscle fibers undergo a process that features degeneration and regeneration. Clinical manifestations include proximal weakness in the first few years of life, pseudohypertrophy, cardiomyopathy (see MYOCARDIAL DISEASES), and an increased incidence of impaired mentation. Becker muscular dystrophy is a closely related condition featuring a later onset of disease (usually adolescence) and a slowly progressive course. (Adams et al., Principles of Neurology, 6th ed, p1415)

The removal of a limb or other appendage or outgrowth of the body. (Dorland, 28th ed)

Mature contractile cells, commonly known as myocytes, that form one of three kinds of muscle. The three types of muscle cells are skeletal (MUSCLE FIBERS, SKELETAL), cardiac (MYOCYTES, CARDIAC), and smooth (MYOCYTES, SMOOTH MUSCLE). They are derived from embryonic (precursor) muscle cells called MYOBLASTS.

The nonstriated involuntary muscle tissue of blood vessels.

A genus of newts of the Salamandridae family found in North America in areas east of the 100th meridian. A common species is NOTOPHTHALMUS VIRIDESCENS.

Renewal or repair of lost bone tissue. It excludes BONY CALLUS formed after BONE FRACTURES but not yet replaced by hard bone.

All of the processes involved in increasing CELL NUMBER including CELL DIVISION.

Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.

The region of the lower limb in animals, extending from the gluteal region to the FOOT, and including the BUTTOCKS; HIP; and LEG.

A growth differentiation factor that is a potent inhibitor of SKELETAL MUSCLE growth. It may play a role in the regulation of MYOGENESIS and in muscle maintenance during adulthood.

Elements of limited time intervals, contributing to particular results or situations.

An alternative to amputation in patients with neoplasms, ischemia, fractures, and other limb-threatening conditions. Generally, sophisticated surgical procedures such as vascular surgery and reconstruction are used to salvage diseased limbs.

A state arrived at through prolonged and strong contraction of a muscle. Studies in athletes during prolonged submaximal exercise have shown that muscle fatigue increases in almost direct proportion to the rate of muscle glycogen depletion. Muscle fatigue in short-term maximal exercise is associated with oxygen lack and an increased level of blood and muscle lactic acid, and an accompanying increase in hydrogen-ion concentration in the exercised muscle.

The inferior part of the lower extremity between the KNEE and the ANKLE.

Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.

Restoration of integrity to traumatized tissue.

Congenital structural deformities of the upper and lower extremities collectively or unspecified.

Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.

The muscles that move the eye. Included in this group are the medial rectus, lateral rectus, superior rectus, inferior rectus, inferior oblique, superior oblique, musculus orbitalis, and levator palpebrae superioris.