PVA and PCL nanofibers are suitable for tissue covering and regeneration.

The aim of the study was to evaluate the safety and efficacy of a new therapeutic approach to skin defects resulting from split thickness grafting. Within the study, nanofiber-based dressings fabricated using polyvinyl alcohol (PVA) and poly-ε-caprolactone (PCL) were used, with different mass density. The study was performed in 1 female minipig. Nine defects (approx. 4x4 cm) were made in the superficial skin layer. The tested materials were applied to the squared skin defect and covered by a Jelonet paraffin gauze, sutured in the corners of the defects. The animal was monitored daily during the healing process (21 days). On day 5, 12, and 27, the healing of the wound was evaluated, and a biopsy was performed for further histologic testing. At the end of the study (on day 27 after the procedure), the animal was euthanized, and a standard pathologic evaluation was performed. We can conclude that the nanofiber scaffold which was well tolerated, could be used as a smart skin cover which could be functionalized with another bioactive substances directly on the surgeon table, among potential bioactive substances belong platelet derivatives, antibiotics, etc.

Changes in the composition of fatty acids and lipofuscin-like pigments during development of rat heart.

Postnatal heart development is characterized by critical periods of heart remodeling. In order to characterize the changes in the lipophilic fraction induced by free radicals, fatty acids and their oxidized products, lipofuscin-like pigments (LFP), were investigated. Fatty acids were analyzed by gas chromatography and LFP were studied by fluorescence techniques. A fluorophore characterized by spectral methods was further resolved by HPLC. Major changes in the composition of fatty acids occurred immediately after birth and then during maturation. Fluorescence of LFP changed markedly on postnatal days 1, 4, 8, and 14, and differed from the adult animals. LFP comprise several fluorophores that were present since fetal state till adulthood. No new major fluorophores were formed during development, just the abundances of individual fluorophores have been modulated which produced changes in the shape of the spectral arrays. HPLC resolved the fluorophore with excitation maximum at 360 nm and emission maximum at 410 nm. New chromatographically distinct species appeared immediately on postnatal day 1, and then on days 30 and 60. Consumption of polyunsaturated fatty acids immediately after birth and subsequent formation of LFP suggests that oxidative stress is involved in normal heart development.

Remodeling of fetoplacental arteries in rats due to chronic hypoxia.

The increased fetoplacental vascular resistance due to chronic hypoxia cannot be explained by simple hypoxic vasoconstriction, as it sustains to some degree after recovery in normobaric environment. To verify a hypothesis that fetoplacental arteries undergo remodeling of their walls similar to remodeling of pulmonary arteries in hypoxic pulmonary hypertension, we used a model of the chronically hypoxic rat placenta. Han Wistar pregnant rats were exposed to 14-day hypoxia (10% of oxygen) during the 6th to 19th day of pregnancy. Chronic hypoxia elicited in both intraplacental (prelabyrinthine) and chorionic plate (insertion) arteries significant narrowing of their lumina. Irregular thickening of their adventitia due to an increase in collagen fibers as well as ground substance was observed; reticular fibers were fragmented. Because of remodeling of fetoplacental arteries, a model of chronically hypoxic rat placenta could simulate human preplacental hypoxia and consequent effects.

Effect of an adrenergic agonist and a cholinergic antagonist on the airway epithelium.

The ultrastructure of the rabbit tracheal epithelium was studied 30 minutes after intratracheal administration of two puffs of salbutamol and ipratropium bromide, respectively. The injury to the tracheal epithelium due to the treatment with both bronchospasmolytic drugs was considered moderate to severe. In both experimental groups, the degree of goblet cells' stimulation did not differ significantly, the ciliated cells were less damaged compared with the goblet ones and the morphological signs of the impaired self-cleaning ability were revealed.

Ultrastructure of the tracheal epithelium in rabbits after acetylcholine administration.

The ultrastructure of the tracheal epithelium was studied 5 and 20 min after intravenous (i.v.) administration of 0.5 mg of acetylcholine. As a result of this treatment, the goblet cells were overstimulated and damaged, and the mechanism of their secretion was accelerated. Only a mild pathological alteration was encountered in the ciliated cells. According to our classification, the degree of secretory element damage was severe, the injury to the ciliary border was moderate. The morphological signs of the severe impairment of the self-cleaning ability of the epithelium were inspissated mucus and very numerous bacteria in the area among free cilia.

Comparison of the effect of a high and low dose of atropin on the ultrastructure of the tracheal epithelium.

The ultrastructure of rabbit tracheal epithelium was studied 20 min after injection of 0.04 and 0.5 mg of atropin. The tracheae were lined with altered ciliated pseudostratified columnar epithelium. The degree of damage to the epithelial cells was dose dependent. The injury to the tracheal epithelium due to treatment with 0.04 mg of atropin was considered mild. The administration of the higher dose of atropin caused moderately severe epithelial damage. Both experimental groups exhibited morphological signs of impaired self-cleaning ability.

An abnormally high occurrence of malformed kinocilia in the tracheal epithelium of a clinically healthy rabbit.

An abnormally high occurrence of malformed kinocilia containing axonemes with different number or arrangement of microtubules compared with the typical 9+2 pattern of motile cilia was encountered in the tracheal epithelium of one clinically healthy rabbit. The malformed cilia amounted to 6.87% of all kinocilia. Individual types of ciliary malformations were further classified. The frequency of ciliary malformations was compared with that in all other rabbits the ciliary border of which has been quantitatively evaluated in our laboratory. Using Grubbs test the extremely low probability of occurrence of such a high number of malformed kinocilia in the rabbits' population was verified. The studied rabbit suffered from a mild form of the immotile cilia syndrome, but the loss of less than 10% of moving cilia did not lead to the expression of the clinical signs of the impaired function of cilia in the organism.