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M M Umnova

Publications and source records attributed to M M Umnova.

35 records · Page 2Linked to original sources
PubMed1978

[Comparative analysis of the regenerative activity o the muscular and neural tissues after trauma and after transplantation of minced muscle].

Regenerative processes in the body muscle of fish Variocorhinus capoeta sevangi were studied both after the excision of a portion of three muscle segments and following autografting minced muscle into the defect formed. Muscle trauma resulted in a damage field, including the defect and the adjacent degeneration zone. The inflammation, necrotic mass resolution and regeneration of the nerve and muscle tissues were lengthy. Formation of myogenic elements started during the 3rd week only. Individual regenerating nerve fibers in the damage zone appeared 2 months later. Filling the defect with minced muscle accelerated the regeneration. The grafted muscle fiber fragments were not only involved in the regenerative process, but also stimulated the plastic activity of the muscle and nerve tissues of the grafted bed.

Animals↗
PubMed1977

[Autotransplantation of whole muscles in reptiles].

Whole gastrocnemius muscles were autotransplanted (replanted) to tortoises testudo horsfieldi, 300-500 g in weight. The grafts were examined 2 weeks to 6 months after the transplantation. In 5 to 6 months the replanted muscles were similar in colour and form to the intact symmetrical muscles, constituting 77% of the latter in weight. Regeneration in the grafts proceeded at a slower rate than in mammals. The separation of myoblasts from the degenerating muscle fibers was intensive during the first month and continued for up to 2 months after the transplantation. Differentiation of myogenic elements into cross-striated muscle fibers and graft vascularization were recorded. Most of the grafts were characterized by a muscle type of structure at the final stage of the experiment; however, the muscle fibers diameter varied greatly.

Animals↗
PubMed1977

[Influence of the nervous system on the process of transplantation regeneration of skeletal muscle].

Completely excised Testudo horsfieldi gastrocnemius muscles were regrafted to the same site both with the nerve brought in contact with the graft and under denervation. The restoration of contractility and innervation of the grafts from the contacting nerve started one month after the operation and had not been completed 6 months after the operation. The grafts had a muscular structure type only after the restoration of innervation; otherwise, the connective tissue developed in the grafts. Two months after the operation a significant difference in the weight of the innervated and denervated grafts was recorded. With regard to restoration of innervation and graft weight indices, T. horsfieldi proved to be intermediate between the previously examined rat and frog.

Animals↗
PubMedDate not supplied

[Ultrastructure of the neuromuscular junctions in the rat soleus muscle under varying gravity conditions].

Changes in the ultrastructure of neuromuscular junctions have been considered as an index to adaptation of Wistar rats (whose pre- and postnatal ontogenesis proceeded on a centrifuge under constant rotation until the age of two months) to the hypergravity conditions (2G) and, then, to earth gravity (1G): on the 2nd and 15th days after centrifuge stoppage. The dynamic of synaptic vesicles was shown: their number increased at 2G and gradually decreased at 1G. Local damage of muscle fibers, partial separation of the motor axonal terminal from intrafusal fiber, and membrane twisting were noted at the increased gravity-dependent static load (2G). Neuromuscular junctions with signs of remodeling occurred more frequently in the experimental rats than in the control ones. It was proposed that adaptation of rats to 1G gravity after a prolonged sojourn under the hypergravity conditions (2G) was not completed within the studied period.

Animals↗
PubMedDate not supplied

[Ultrastructure of type 2A extrafusal muscle fibers and intrafusal fibers of the muscle spindle (m. quadriceps femoris) from the adult rat after long-term swimming].

We compared the ultrastructure of type 2A extrafusal muscle fibers, the nuclear chain, and other intrafusal fibers of muscle spindle (muscle stretch mechanoreceptor) in adult rats after a prolonged swimming (5-10 h/day, 10 days). The Golgi apparatus was expressed moderately in type 2A extrafusal fibers and hypertrophied in the motor B zone of nuclear chain intrafusal fibers. Intense development of the Golgi apparatus in the nuclear chain intrafusal fiber appears to be related to glycogenolysis in the autophagous vacuoles, involvement in the lysosome activity, and plasma membrane renewal. "Recapitulation" of the mechanism of glycogen autophagy, which is observed in newborn rats during mobilization of glycogen from the liver and muscle, was demonstrated in adult rats under the influence of physical load in the nuclear chain and nuclear bag 2 intrafusal fibers and in type 2A extrafusal fibers. This is accounted for by a weak differentiation of the intrafusal muscle fibers: structurally, they are similar to myotubes and have specific features of blood supply and innervation. Individual features of experimental adult rats may also play a certain role.

Animals↗
PubMedDate not supplied

[Ultrastructure of muscle spindles (Mechanoreceptors) of Rat m. soleus after support unloading and its combination with hypergravity].

We used electron microscopy to evaluate the effect of support unloading of m. soleus in adult Wistar rats (restrained in an antiorthostatic posture for 23-24 h/day within 24 days) on the ultrastructure of the intrafusal fibers and motor neuromuscular junctions of the muscle spindles, as well as the efficiency of intermittent hypergravity (+2Gz; 1 h/day for 19 days in a centrifuge in hypokinetic cages) as a countermeasure used in conditions of support unloading of this muscle. In the absence of support on the hind limbs, most of intrafusal fibers of m. soleus preserved the typical ultrastructure, while the axon terminals of the neuromuscular junctions accumulated a lot of synaptic vesicles (including large vesicles); the coated vesicles were absent due to unloading of the muscle and its muscle spindles (no contractions of the intrafusal fibers). A short-term effects of hypergravity at the background of support unloading of m. soleus mostly induced static loading of the muscle inducing different responses of the intrafusal fibers in different regions of the muscle spindles: local lysis of myofilaments was observed in single intrafusal fibers of the equatorial and intracapsular motor regions, while myofibrils remained intact in most fibers in the intra- and extracapsular regions of the spindles. The revealed adaptive response of the intrafusal fibers is, on the one hand, due to their specific innervation and ultrastructure and, on the other hand, to positive effect of hypergravity on the motor and extracapsular regions of the muscle spindles. Hypergravity decreased the number of synaptic vesicles and induced appearance of the coated vesicles in the axon terminals of the neuromuscular junctions of the intrafusal fibers in the animals restrained in an antiorthostatic posture (support unloading of m. soleus), which is due to increased functional load of the muscle. The ultrastructure of the muscle fibers adequately reflected the functional status of the postural m. soleus both during support unloading and support unloading combined with hypergravity load.

Actin Cytoskeleton↗
PubMedDate not supplied

[The absence of support loading on the rat m. soleus leads to an increase in the number of intrafusal muscle fibres in muscle spindles].

The ultrastructure of muscle spindles (incapsulated mechanoreceptors of stretch of extrafusal muscle fibres) of m. soleus in adult Wistar rats after repeated unloading of support on hind limbs with preservation of support loading on fore limbs has been studied by transmissing electron microscopy. It was shown that, along with muscle spindles with the ordinary number of intrafusal muscle fibres (four), m. soleus contains spindles with an increased number of intrafusal fibers (five to six). It was assumed that the increase in the number of intrafusal muscle fibers is due to the proliferation of their satellite cells.

Animals↗