Nine volunteers, aged 27 to 41 years, were exposed to 370-day head-down tilting during which their tibia bones were examined by measuring acoustic parameters with the aid of exponential point concentrators located at a 15 mm distance. Although the bone acoustic profile showed individual variations, the decrease of the average ultrasound velocity in the middle part and the gradient of the ultrasound velocity in the distal part of the diaphysis occurred primarily in the first half of the bed rest study, thus reflecting changes in bone adaptation to mechanical loads (redistribution of elastic properties along the bone). The acoustic parameters measured noticeably responded to countermeasures used (or not used) during bed rest (exercise) and therefore can help obtain better prognostic information about bone is compared to the data accumulated by means of monophoton absorptiometry (mineral density measurement). This method can be well used for examining long bones in extended space flight.

Adult↗

PubMedDate not supplied

[Bone examination by noninvasive methods during prolonged hypokinesia].

The effect of 120-day bed rest on skeletal bones of 15 volunteers was investigated by noninvasive methods, viz. gamma-photon absorption, ultrasonic and neutron-activation analysis. The test subjects were divided into 4 groups one of which served as control and three others used different countermeasures (drugs, exercise or drugs in combination with exercise). Calcium loss in skeletal bones was not more than 0.5% per month; calcium loss in leg tubular bones was 1 to 2% per month in 6 test subjects; calcium loss in heel bones was on the average 3-4% per month in the control, exercise and combination groups. No strict correlation between the negative balance of calcium and mineral content in leg compact bones and foot spongy bones was found. There was a correlation between changes in the mineral content of leg bones and ultrasound propagation along certain compartments of the tibial median surface. In terms of negative and positive trends leg and foot bones were in better condition in the drug group. The techniques used were assessed with respect to their diagnostic and prognostic value.

Bone and Bones↗

PubMedDate not supplied

[Use of electric stimulation for activating the process of bone consolidation].

A method of electrostimulation aimed at activation of bone adhesion processes was developed and introduced into practice at the Latvian Research Institute of Traumatology and Orthopedics on the basis of data on bone bioelectric activity. The method was used in complex with external fixation of the fracture by Kalnbers' apparatus. The phase pattern of callus formation necessitated the employment of the appropriate potential of direct current. Cyclic potentials similar to piezopotentials of a normal bone in cyclic physiological load were used in the phase of functional reorganization. Positive results were achieved in 88.4% of 79 patients.

Bone and Bones↗