[Formation of ossification nucleus in the femoral head in hamsters exposed to laser radiation].

The purpose of the study was to detect the relation between the formation of ossification nucleus in the epiphysis and the ingrowth of vessels into it, using laser radiation of femoral heads. The study was performed in 30 golden hamsters, 20 of them starting at 10 days after birth were exposed to daily irradiation of the right hip joint (during 3-80 days). The left joint was used as control. The radiation was performed with Agnis laser device (radiation power--2 mW, impulse frequency--2500 Hz, exposure duration--8 min, optical fiber diameter--4 mm). Femoral bones of experimental and control animals were histologically studied at days 13 till 90. Laser radiation was found could delay vessel growth from diaphysis into epiphysis for up to 13 days, and the beginning of ossification nucleus formation in the femoral head--for up to 5 days. This suggests the direct relation of the development of bone ossification nucleus in the epiphysis and growing of vessels into its cartilage, since no other factors retarding the vessel growth and formation of bone nucleus were used.

[Deceleration of vascular growth--a cause of varus hip deformity]. / Zamedlenie rosta sosudov--prichina varusnoi deformatsii bedra.

The aim of this study was to examine the peculiarities of femoral proximal epiphysis formation following the early disruption of its blood supply. The experiments were performed using 20 albino rats that were operated at postnatal day 18 having their diaphysis and acetabular arteries cut in one extremity (the other extremity serving as control). Starting at postoperational month 2 and up to month 12, 1-2 animals were sacrificed monthly by ether overdosage. Femoral and pelvic bones were removed from both control and experimental extremities, fixed in neutral formalin, decalcified, dehydrated and embedded in celloidin. The sections were stained with hematoxylin and eosin. It was established that a deceleration of vascular growth compromised the nutrition of the cartilage of the femoral proximal epiphyseal growth plate. This resulted in the delay of chondrocyte differentiation and prevented the timely formation of the bone in the area of femoral collum, causing the development of varus deformity.

[Participation of bone marrow stromal precursor cells and bone regeneration during transosseous osteosynthesis]. / K voprosu ob uchastii stromal'nykh kletok-predshestvennikov kostnogo mozga i regeneratsii kosti pri chreskostnom osteosinteze.

Changes in the proliferative activity and in the number of bone marrow stromal precursor cells (SPC) in the dog long bone fixed with Ilizarov's apparatus were studied by cloning in monolayer cultures over a period of leg lengthening. It was demonstrated that in 1-1 1/2-year-old dogs the number of dividing SPC in the tibia increased up to 95% by termination of the distraction (60 days). Concurrently, the colony-forming efficiency (CFE) increased 11-fold. In the contralateral tibia (CFE significantly rose during the distraction, while in the humeri it decreased 2.5-fold as compared to control. A conclusion is drawn about participation of SPC in bone regeneration.