"Solvent/non-solvent" treatment as a method for non-covalent immobilization of gelatin on the surface of poly(l-lactic acid) electrospun scaffolds.

In the present study, we report a simple and efficient method of gelatin immobilization on the surface of PLA electrospun fibers using pre-treatment with a mixture of toluene and ethanol allowing to form swelled surface layer followed by gelatin adsorption from its solution in PBS. Our results demonstrate that gelatin immobilization leads to a decrease in the water contact angle from 120° to 0°, enhances scaffold strength up to 50%, and doubles the number of adhered cells and their average area. We observed that the maximum amount of gelatin (0.07 ± 0.01 mg per cm3 of the scaffold) was immobilized during the first five minutes of exposure to the gelatin solution. Modified scaffolds demonstrated increased strength.

Experimental Study of a Radiopharmaceutical Agent Based on Modified Fatty Acid Labeled with Technetium-99m.

Using rat model of coronary occlusion, we studied pharmacokinetics and the efficiency of a new radiopharmaceutical agent 99mTc-PDA-DTPA intended for diagnostics of changes in myocardial metabolism and its analogue 123I-PMPDA. 99mTc-PDA-DTPA was eliminated mostly by the kidneys and maximal concentration in the heart was attained within 60 min after intravenous injection; no accumulation in the area of myocardial infarction was observed. The studied substance was inferior to its analogue 123I-PMPDA by the quality of scintigraphic visualization of the heart.

[Evaluation of manganese-trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetate complex (Cyclomang) as paramagnetic contrast agent for magnetic resonance imaging].

Preclinical evaluation of a 0.5 M solution of the manganese(II)- trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetate complex (Mn-DCTA, Cyclomang) has been carried out with a view to substitution of potentially toxic gadolinium-containing paramagnetic contrast agents for clinical MRI routines. The toxicological tests of Mn(II)-DCTA were performed on mice and rats. Liquid phantoms were used for evaluating the relaxivity of Mn(II)-DCTA in comparison to that of Gd(III)-DTPA and Mn-DTPA. The diagnostic imaging properties of Mn(II)-DCTA were quantitatively assessed on dogs with cerebral meningeomas (n = 10). The LD50 upon single administration in rats was above 17 ml/kg, thus slightly exceeding the corresponding values for of Gd(III)-DTPA and Mn-DTPA. The relaxivity of Mn(II)-DCTA amounted to R1 = 3.68 (mM(-1) x s(-1)) and did not differ significantly from the values known for Gd-DTPA and Mn-DTPA. Mn(II)-DCTA ensured high-intensity contrast of tumor areas in brain of dogs. It is concluded that Mn(II)-DCTA can be employed as a paramagnetic contrast agent in routine MRI studies and is worth further clinical evaluation.

[Preclinical investigation of Mn(II)-diethylenetriaminepentaacetate (Mangapentetate) as paramagnetic contrast agent for magnetic resonance tomography].

The preclinical evaluation of 0.5 M solution of a manganese(II)-DTPA complex (Mangapentetate, Pentamang) has been carried out in order to test the ability of manganese to be used as substitute for potentially toxic gadolinium in paramagnetic contrast agents in the MRI clinical routines. The toxicologic tests of the Mn(II) - DTPA were carried out in mice, rats, and rabbits. Liquid phantoms served for direct comparison of the ability of Mn(II) - DTPA to increase the intensity of T1-weighted SE-images to the contrast properties of the Gd(III) - DTPA (Magnevist). Normal healthy rabbits (n = 12) were used for quantification of the imaging ability of Mn(II) - DTPA. The value of LD50 in rabbits was above 10 ml/kg, rather close to that one of Gd(III) - DTPA. An increase in intensity of the T1-weighted images induced by addition of Mn(II) - DTPA in phantom tests did not differ significantly from the values obtained with Gadopentetate. Mn(II) - DTPA delivered prominent enhancement of normal kidneys in healthy rabbits as well as chest tumors in dogs.

[Preclinical toxicological evaluation of Pentamang and Mangascan].

We have carried out a preclinical toxicological investigation (acute toxicity evaluation) of Mangascan (0.5 M solution of manganese(II) - EDTA complex) and Pentamang (0.5 M solution of manganese(II) - DTPA complex), a new paramagnetic contrast agents for MRI procedures. In 14 days after single intravenous introduction of Mangascan (10.0 ml/kg) or Pentamang (5.0 ml/kg) to rats, no any toxic influence of the studied agents was detected in the general condition, bone marrow, cardiovascular and central nervous systems, and liver and kidney functions of experimental animals. No pathological changes were observed in the functional activity and morphology of the internal organs and systems. The results showed that both Mangascan and Pentamang belong to the class of low toxicity substances.