A method for evaluating the fluctuations in the intensity of substance transport between blood and bones in the predominant direction.

The dynamics of fluctuations in the intensity of the blood-bone flow of substances in the predominant and opposite directions was evaluated using the percent radioactivity difference coefficient and its graphic presentation. The technology of calculating this coefficient is described.

A new method for evaluation of radioactive label transport intensity in the predominant direction between blood and liver.

The intensity of (75)Se transport in the predominant direction after intraperitoneal injection of [(75)Se]selenate was compared in 1- and 3-month-old rats receiving common vivarium ration or sucrose diet. The incorporation percent, blood/liver relative radioactivity, and relative radioactivity difference coefficient were evaluated in the blood and liver. The dynamics of label incorporation in the blood of rats fed common diets has two peaks (at 1-3 h and 12-24 h) and a drop at 6 h. Coefficient of difference in 1-month-old rats was characterized by a greater amplitude of fluctuations than in 3-month-old animals.

Effects of selenium-containing compounds and their metabolism in intact rats and in animals with bone fractures.

Blood content of MDA in rats increased 1 and 2 weeks after mandibular bone fracture at stages of cellular fibrous and chondroid callus and decreased 4 weeks after fracture at the stage of primary bone callus. Treatment with Se (intragastrically and electrophoretically) reduced this increase by activating selenium-containing glutathione peroxidase. In order to clear out the relationship between Se and carbohydrate metabolism in different ages, the distribution of Se between the blood and mandibular bone, diaphysis and metaepiphyseal zone of the femoral bone was studied using the bone/blood relative radioactivity coefficient after intraperitoneal injection of [(75)Se]selenate. In control 1-month-old rats the radioactivity had 2 peaks corresponding to 6 and 48 h. The first peak was presumably caused by Se adsorption on hydroxyapatite, the second by chemosorption on hydroxyapatite and protein binding. Only one peak of relative radioactivity (after 12-48 h) was observed in 3-month-old control rats, and it could be increased by sucrose diet. The relative radioactivity was higher in rats receiving sucrose ration for 2 months starting from the age of 1 month in comparison with the control.

Study of labeled carbonate metabolism in healthy organisms during reparative osteogenesis and denervation by the bone/plasma index.

We studied the effect of mandibular fracture and denervation on [(14)C]carbonate metabolism. A new index (bone/plasma relative radioactivity) reflecting the ratio between (14)C incorporation into bone and plasma was proposed. The percentage of label incorporation and bone/plasma relative radioactivity were measured from the 5th minute to the 192nd hour after intraperitoneal injection of labeled carbonate to 1-2-month-old albino rats. We revealed a biphasic reaction: rapid accumulation and elimination of the isotope form the bone; and slow accumulation followed by slow accumulation and elimination. Changes in carbonate metabolism after bone fracture corresponded to phases of reparative osteogenesis. At the stage of cellular-and-fibrous callus accumulation of labeled carbonate dominated over its elimination. At the stage of chondroid callus elimination dominated over accumulation. At the stage of primary osseous callus elimination dominated over accumulation, but did not surpass the control level. After fracture the index of bone/plasma relative radioactivity underwent general changes that were most pronounced in the zone of trauma. After denervation this index also decreased.

Labeled citrate metabolism in bone fractures and impaired innervation.

Changes in (14)C incorporation into regenerate after bone fracture and impairment of mandibular innervation, and injection of [3-(14)C]cytrate corresponded to the stages of reparative osteogenesis: after 1 week (14)C incorporation in the cellular-fibrous callus surpassed its release, after 2 weeks the rates of (14)C incorporation and release in the chondroid callus become similar, and after 4 weeks the release of the label predominated in the primary bone callus. Denervation reduced (14)C incorporation into regenerate, which impaired bone remodeling. Citrate in the bones is characterized by high metabolic activity.