Transtraumatic Epidural Electrostimulation of the Spinal Cord in a Pig Model.

The effect of transtraumatic epidural electrostimulation (TEES) above (T5) and below (L2) spinal cord injury in the lower thoracic region (T8-T9) in combination with treadmill exercise in pigs was evaluated using electrophysiological examination methods and behavioral tests. Two weeks after spinal cord injury, motor evoked potentials of m. soleus were recorded during electrostimulation at the level of T5 and L2 segments, which indicated activation of spinal cord structures above and below the focus of injury. After 6 weeks of TEES in combination with physical training, restoration of the characteristics of M-response and H-reflex of the soleus muscle in response to stimulation of the sciatic nerve, improvement of joint mobility, and appearance of voluntary motor activity in the hindlimbs were observed. Neuromodulation with TEES had been proven to be an effective way to stimulate posttraumatic spinal cord regeneration and can be used in the development of a neurorehabilitation protocol for patients with spinal cord injury.

A New Mass Burial of Cave Bears (Carnivora, Ursidae, Ursus kanivetz, Vereshchagin, 1973) from the Middle Urals.

Remains of a cave bear were studied from a new locality in the Prokoshev Cave in the Middle Urals (58°13´ N, 58°12´ E). Bones from all regions of the skeleton are present, bones are intact and without traces of human or animal activity. They all belong to the cave bear (Ursus kanivetz Vereshchagin, 1973). An AMS radiocarbon date of 53 375 ± 765 BP, IGANAMS-8632, was obtained from an adult mandible. The bones belonged to at least 18 individuals, including 4 individuals aged about one year, 1 aged about two years, 1 aged about three years, and 12 individuals over four years of age. Three skulls belonged to males and seven skulls belonged to females. The analysis has shown that the taphonomic type of this locality is a "mass burial." This is the first "mass burial" of the cave bear in the Urals, found in situ, untouched by humans.

Integrating multiple sensory systems to modulate neural networks controlling posture.

In this study we investigated the ability of sensory input to produce tonic responses in hindlimb muscles to facilitate standing in adult spinal rats and tested two hypotheses: 1) whether the spinal neural networks below a complete spinal cord transection can produce tonic reactions by activating different sensory inputs and 2) whether facilitation of tonic and rhythmic responses via activation of afferents and with spinal cord stimulation could engage similar neuronal mechanisms. We used a dynamically controlled platform to generate vibration during weight bearing, epidural stimulation (at spinal cord level S1), and/or tail pinching to determine the postural control responses that can be generated by the lumbosacral spinal cord. We observed that a combination of platform displacement, epidural stimulation, and tail pinching produces a cumulative effect that progressively enhances tonic responses in the hindlimbs. Tonic responses produced by epidural stimulation alone during standing were represented mainly by monosynaptic responses, whereas the combination of epidural stimulation and tail pinching during standing or epidural stimulation during stepping on a treadmill facilitated bilaterally both monosynaptic and polysynaptic responses. The results demonstrate that tonic muscle activity after complete spinal cord injury can be facilitated by activation of specific combinations of afferent inputs associated with load-bearing proprioception and cutaneous input in the presence of epidural stimulation and indicate that whether activation of tonic or rhythmic responses is generated depends on the specific combinations of sources and types of afferents activated in the hindlimb muscles.

Formation of locomotor patterns in decerebrate cats in conditions of epidural stimulation of the spinal cord.

Acute experiments on decerebrate cats were performed to study the mechanism of formation of the locomotor pattern in conditions of epidural stimulation of the spinal cord. These studies showed that only segments L3-L5 contributed to generating the stepping pattern in the hindlimbs. At the optimum frequency (5-10 Hz) of stimulation of these segments, formation of electromyographic burst activity in the flexor muscles was mainly due to polysynaptic reflex responses with latencies of 80-110 msec. In the extensor muscles, this process involved the interaction of a monosynaptic reflex and polysynaptic activity. In epidural stimulation, the stepping pattern was specified by spinal structures, while peripheral feedback had modulatory influences.

Initiation of locomotor activity in spinal cats by epidural stimulation of the spinal cord.

Acute and chronic experiments on lower spinal (T10-T12) cats were performed to investigate the effects of epidural stimulation of the dorsal surface of the spinal cord on the initiation of locomotor activity. A zone located at the border between segments L4 and L5 was identified, stimulation of which induces locomotor activity. The parameters of epidural stimulation of the spinal cord effective in activating the stepping movement generator were identified. Epidural stimulation leading to the initiation of movement activity was shown to depend on intracentral and peripheral mechanisms activating the segmental, intersegmental and propriospinal reflex systems of the spinal cord. A leading role was demonstrated for the propriospinal system of the dorsolateral funiculi in activating the generators of stepping movements in epidural stimulation of the spinal cord.

[Features of stepping pattern formation in decerebrated cats under epidural spinal cord stimulation]. / Osobennosti formirovaniia lokomotornykh patternov u detserebrirovannoi koshki pri épidural'noi stimuliatsii spinnogo mozga.

The mechanisms of stepping pattern formation initiated by epidural spinal cord stimulation in decerebrated cats, were investigated. It is shown that the ability to produce the stepping pattern involve the L3-L5 segments. In flexor muscle, the formation of stepping pattern under optimal stimulation frequency (5-10 Hz) of these segments is provided by polysynaptic activity with the latency 80-110 ms. In extensor muscle, this process is realized through interaction of monosynaptic reflex and polysynaptic activity. The stepping pattern under epidural stimulation is determined by spinal structures with modulation influence of the peripheral feedback.

[The effect of complex barometric exposure on hemodynamics during simulation of the physiological impacts microgravity in animals]. / Vliianie kompleksnogo barovozdeistviia na gemodinamiku u zhivotnykh pri modelirovanii fiziologicheskikh éffektov mikrogravitasii.

In experiments with anesthetized cats effects of breathing under negative pressure (BNP, -5 cm of water column) combined with lower body negative pressure (LBNP, -20 cm of water column) on the cardiorespiratory reactions to postural simulation of the hemodynamic shifts in microgravity were studied. Evidence was obtained that this complex barometric exposure of tilted animals (-30 degrees) imitated the central and peripheral hemodynamics characteristic of tilt at the calculated inclination of +6 degrees up to +12 degrees. Extrapolation of the experimental data on the orthodox physiological model of microgravity (HDT, -6 degrees) allows an assumption that the protocol of complex barometric exposure tested in this experiment transforms the hemodynamic parameters under study to the levels close to those in the vertical body. Results of the investigation infer an additive character of the complex barometric exposure (LBNP + BNP) and its utility as a model of orthostatic g-loads.

[Initiation of locomotor activity in spinalized cats by epidural stimulation of the spinal cord]. / Initsiatsiia lokomotornoi aktivnosti spinalizirovannykh koshek pri épidural'noi stimuliatsii spinnogo mozga.

An area initiating locomotor activity under conditions of the spinal cord surface stimulation (SCS) was found at the upper border of the lumbar enlargement (L4-5 spinal segments). Parameters of the SCS for activation of the spinal stepping generator (SSG) were identified. Activation of the SSG under the SCS was shown to occur because of interaction of the spinal and peripheral mechanisms. Primary role in the SSG initiation during the SCS belongs to the propriospinal system of the dorsolateral funiculi.

[Treatment of femoral neck fractures using carbon implants]. / Lechenie perelomov bedrennoi kosti s pomoshch'iu uglerodnykh implantatov.

The article generalizes the experience in the use of endoprostheses of carbon materials in fractures of the femoral neck in elderly individuals. Twenty-seven cases are discussed, the average age of the patients was 76 years. Owing to the possibility of forming from carbon materials a device which meets the functional demands of the organs and tissues, such widely encountered complications in endoprosthesis as stretching of the implant's pedicle and destruction of the device were avoided.

[Joint prosthetics using carbon implants]. / Protezirovanie sustavov uglerodnymi implantatsiiami.

A group of "Intost" materials based on carbon were developed by the I. M. Sechenov Moscow Medical Academy jointly with the Research Institute of Graphite. After experimental studies the materials were authorized for use in clinical practice for implantation. A concept of the design of endoprostheses of the joints from "Intost" was developed, on the basis of which unipolar combined endoprostheses of the hip joint (127 cases), metatarsophalangeal articulation (27 cases), humeral and metacarpophalangeal articulations (two cases each), and condyles of the tibia (5 cases) were made and applied in clinical practice. A detailed analysis is given of ten years of experience gained with the use of the combined unipolar endoprosthesis of the hip joint manufactured from "Intost-1" and "Intost-3". Long-term beneficial results were obtained in 95% of patients. Endoprosthesis is recommended for the treatment of fractures and false joints of the neck of the femur in elderly and senile patients.

[Filling-in of bone margin defects with carbon implants]. / Zameshchenie kraevykh defektov kosti uglerodnymi implantami.

The article contains data of using carbon implants of syntactic foam to replace marginal defects of bone tissue of finger phalanges and metacarpal bones after excision of enchondromas. Sixteen clinical observations are reported.

[Local hypothermia of the spinal cord in the postoperative period]. / Lokal'naia gipotermiia spinnogo mozga v posleoperatsionnom periode.

The authors analyse their observations over 19 patients with acute and neglected trauma of the spinal cord. The patients' ages ranged from 19 to 53 years. The planned and emergency operations on the 19 patients comprised laminectomy with the use of an optic magnifier and some plastic operations on the spinal cord with the use of microsurgical techniques (suturing of roots, opening intracerebral cysts, etc.). Local hypothermia was applied in the postoperative period for the prevention of hemorrhage and oedema of the spinal cord, for relief of spasms and pain, and for the inhibition of auto-immune processes in the spinal cord. The authors confirm that local hypothermia of the spinal cord does not affect body functions and exerts a selective effect on the area exposed to hypothermia. The general positive effect of local hypothermia of the spinal cord in the postoperative period is also pointed out.