In vitro examination of degenerative evolution of adrenergic nerve endings in pulmonary inflammatory [corrected] processes in newborns.

Morphological aspect of tracheal preparations and pulmonary tissue was studied in vitro. The material was obtained from autopsy of newborns that died from different causes. Examinations were made in different gestational periods (immature 23-29 weeks; premature 30-37 weeks; mature >38 weeks). Material for examination was obtained up to 6 hours after death. Pulmonary and tracheal tissue was incubated for fixation in buffered formalin (10%). Special histochemical and histoenzymatic methods were used for coloring of pulmonary and tracheal tissue and the activity of ATP-ase and dopaoxidase was monitored. Cut out models were made in series of 7 micro, 10 micro and 20 micro. In peripheral axons of tracheobronchial pathways, degenerative alterations of adrenergic nerve endings in lung inflammatory processes were documented. These morphologic neuronal changes were described: Walerians degeneration, neuro-axonal degeneration and segment demyelinisation. These changes are well seen with argentafine coloring (Sevier-Munger modification for nerve endings) and with dopaoxidase reaction. In mature newborns that died from respiratory distress syndrome, we found different forms of metabolic and toxic degenerative damage in peripheral axons, such as: segment demyelinisation, neurotubular fragmentation, Schwann cell proliferation, fragmentation and bulging out of axonal neurotubules and neurofilaments. In tracheo-bronchial tissue, chromafine granules are homogeneously distributed on Lamina propria layer and through glandular structures. This gives as a contradiction, according to some authors, that adrenergic nerve fibers for muscle tissue are absent and that adrenaline and noradrenaline diffuse in muscle tissue from interstice.

In vitro examination of ontogenesis of developing neuronal cells in vagal nuclei in medulla oblongata in newborns.

The development of neuron cells in vagal nerve nuclei in medulla oblongata was studied in vitro in live newborns and stillborns from different cases. Morphological changes were studied in respiratory nuclei of dorsal motor centre (DMNV) and nucleus tractus solitarius (NTS) in medulla oblongata. The material from medulla oblongata was fixated in 10 micro buffered formalin solution. Fixated material was cut in series of 10mu thickness, with starting point from obex in +/- 4 mm thickness. Special histochemical and histoenzymatic methods for central nervous system were used: cresyl echt violet coloring, tolyidin blue, Sevier-Munger modification and Grimelius coloring. In immature newborns (abortions and immature) in dorsal motor nucleus of the vagus (DMNV) population stages S1, S2, S3 are dominant. In neuron population in vagal sensory nuclei (NTS) stages S1, S2 are dominant. In more advanced stages of development of newborns (premature), in DMNV stages S3 and S4 are seen and in NTS stages S2 and S3 are dominant. In mature phase of newborns (maturity) in vagal nucleus DMNV stages S5 and S6 are dominant, while in sensory nucleus NTS stages S4 and S5 are dominant. These data suggest that neuron population in dorsal motor nucleus of the vagus (DMNV) are more advanced in neuronal maturity in comparison with sensory neuron population of vagal sensory nucleus NTS. This occurrence shows that phylogenetic development of motor complex is more advanced than the sensory one, which is expected to take new information's from the extra uterine life after birth (extra uterine vagal phenotype).

Examination of ontogenetic-morphologic growth of adrenergic receptor system in the isolated preparation of trachea in vitro.

Morphological development of the bronchial respiratory system of the living newborns and dead newborns was studied. Tracheal smooth musculature was studied in 19 experimental preparations which were obtained from autopsy of newborns that died from different causes. Based on the morphological research of the isolated preparation of human trachea the following was stated: numerical density of the tracheal ganglions is higher in the premature. Decrease of ganglion cells number is noticed in mature newborns. This can be explained with the fact that in the phase of intensive ramification, ganglions penetrate from the serous layers in the deeper layers of the trachea--in the direction of epithelium. Main diameter of tracheal ganglions is bigger in premature; this is proportional with the developmental phase of newborns. Based on histological, histochemical and hystoenzymatic analyses, three types of synaptic-axonal neurotransmitter vesicles are visualized in our material: small granularvesicles (SGV), large granular vesicles (LGV) and aminoacid vesicles, with gamma-amino butyric acid and glycine (GABA). Vesicles give positive reaction with argentaffin, argyrophilin and dopa-oxidase. Argentaffin and argyrophile reactions are positive in synapses, hydrocyte cartilage, epithelium, smooth musculature, SGV, LGV, GABA of the tracheal-bronchial pathways. ATP is positive in hydrocyte cartilages and tracheobronchial mucus glands. On airways most of the nerve endings are vesicular (motor) type. Non-vesicular (sensory) types of nerve endings are present in perichondrial localization. These morphological data indicate interaction between adrenergic, cholinergic and third nonadrenergic-noncholinergic system in airways.

Postnatal - physiological research of the bronchial receptor system development on the isolated preparation of the human trachea in vitro.

Research was done on pharmacological-physiological development of the bronchial receptor system on the smooth muscles of trachea in the newborn children, alive-born and stillborn children. Monitored was the response on: acetylcholine, dopamine, histamine and serotonin in different molar concentrations 10(-4), 10(-3), 10(-2), 10 mol/dm(-3), micromol/dm(-3)). Research was done on tonus of tracheal smooth muscles of 23 tracheal preparations taken by autopsy after death from different factors. Based on pharmacological-physiological research on the preparations of human isolated trachea it was find out that: acetylcholine stimulation effect is significant (p>0,01) in 38-41 weeks of pregnancy comparing with that in 30-37 weeks of pregnancy (p>0,01), while dopamine stimulation effect is significant (p>0,05) in 30-37 pregnancy weeks comparing with the effect of acetylcholine and dopamine on the still-born infants of the same pregnancy period (p<0,01). Histaminic receptors were developed during intrauterine life after 38 weeks of pregnancy (p>0,025). Serotonin has caused contraction of the bronchial smooth muscles after 30 pregnancy weeks, but response was not significant (p<0,01). This suggests that cholinergic and adrenergic system of the airways in alive newborn infants develops in parallel intrauterine, contrary to other systems which develop in certain extrauterine life phases.