MORPHOLOGICAL AND BEHAVIORAL ANALYSIS OF THE PROTECTIVE EFFECTS OF BACTERIAL MELANIN IN A RAT MODEL OF PARKINSON'S DISEASE.

A comparative study of the morphological and functional state of the microvasculature of the substantia nigra pars compacta of the brain (SNc) and bone marrow of rats was carried out using the rotenone model of Parkinson's disease (PD) and with subsequent administration of bacterial melanin (BM). The detection of microvasculature was carried out according to the histoangiological method of Chilingaryan. Animal behavior was studied using a cylinder test. An analysis of morphometric data showed that, in comparison with control animals, experimental animals with rotenone dysfunction showed an increase in capillary diameters and a general reduction in the capillary link in SNc. Behavioral tests have shown that the animals with rotenone intoxication exhibit a form of behavior inherent in PD (freezing, immobility, apathy). Under the influence of BM, the diameter of the capillaries in the SNc approaches the norm, and the capillary link is restored. Due to the protective effect of BM in rats with rotenone intoxication, the trophism of the brain tissue increases as a result of the approach of the lumen of the vessels to the norm and the opening of new branches in the capillary network, an increase in the density of capillaries, which ensures the safety of nerve cells. Animal behavior indicators are close to normal. A comprehensive analysis of cytogenetic data of rat bone marrow was also carried out. In animals with PD, compared to controls, there is a significant increase in the amount of polyploid cells (PC) and a decrease in the level of mitotic index (MI), which usually manifests itself in inflammatory processes and is accompanied by inhibition of bone marrow hematopoiesis. Under the influence of BM, a tendency towards normalization of MI was noted and a significant decrease in the percentage of PC was obtained, which possibly indicates its beneficial effect. The data obtained suggest that BM can be used as a therapeutic agent in the treatment of PD.

[Correlation between defects in medical care and data of causal analysis]. / Vzaimosvyaz' mezhdu defektami meditsinskoi pomoshchi i dannymi prichinno-sledstvennogo analiza.

The article is devoted to the current legal responsibility of medical staff. It is noted that this issue has not been sufficiently studied and requires further research. The article identifies an attempt to assess statistically significant correlation between defects of medical care provision and data of causal analysis as a research task. The practical experience on 215 conclusions of commission forensic medical examinations, in which doctors of surgical specialties were considered on «medical cases¼, has been summarized. A high statistically significant correlation between defects in treatment, diagnosis, organization of medical care, management of medical records and data of causal relationship has been established on the basis of performed scientific researches. The idea that, despite possible subjectivism, the causal relationship is confirmed by factual data on revealed defects in medical care obtained from the study, has been proven.

Bacterial melanin improves cognitive impairment induced by cerebral hypoperfusion in rats.

The effect of bacterial melanin (BM) solution on learning and memory impairment induced by chronic cerebral hypoperfusion in rats was studied. Male rats were injected intramuscularly with BM solution on the second day after bilateral permanent occlusion of the common carotid artery. Rats received 6 mg/ml (170 mg/kg) BM and performed significantly better in cognition tests compared with controls. The present findings demonstrate that the beneficial effects of BM injection on cognitive functions may be due to preventing neuropathological alterations, suppressing the inflammation process, stimulating vascularization and inhibiting oxidative damage. Obtained data suggest that BM has therapeutic potential for the treatment of neurodegeneration caused by ischemia.

Bacterial melanin increases electrical activity of neurons in Substantia Nigra pars compacta.

Bacterial melanin (BM) has been used in different series of experiments as a neuroprotector. It facilitates recovery and regeneration processes after CNS lesions. The action of BM after Substantia Nigra destruction is of major interest. Electrophysiological study tries to reveal the effects of this substance on the electrical activity of Substantia Nigra pars compacta (SNc) neurons. The substance significantly increases the firing rate of SN cdopaminergic neurons. BM increases the rate of excitatory responses after high frequency tetanic stimulation of ipsilateral caudate­putamen. Overall increase in firing rate of SN neurons can contribute to recovery processes after neuronal degeneration in SN.

Effects of bacterial melanin on movement, posture, and skilled balancing deficits after unilateral destruction of substantia nigra pars compacta in rats.

Sixteen adult male rats were initially trained to an instrumental conditioned reflex (ICR) and subjected to unilateral destruction of substantia nigra pars compacta. Part of the animals was injected with bacterial melanin solution on the next day of destruction. The other 8 rats served as the control group. Recovery rates for ICR and dynamics of paralyzed hindlimb movements were studied in both groups. Conditioned reflex and contralateral to lesion hindlimb movements recovered faster in rats injected with bacterial melanin after the destruction.

Effects of bacterial melanin on motor recovery and regeneration after unilateral destruction of Substantia Nigra pars compacta in rats.

We examined the potential neuroprotective action of bacterial melanin (BM) in rats after unilateral destruction of Substantia Nigra pars compacta (SNc) dopaminergic neurons. 24 rats were initially trained to an instrumental conditioned reflex (ICR) and then subjected to unilateral electrolytic destruction of SNc. Unilateral deficit in balancing hindlimb movements was observed in all rats after the destruction. On the next day after the destruction part of the animals (n=12) was intramuscularly injected with BM solution at the concentration 6 mg/ml (0.17 g/kg). The other 12 operated rats served as a control group. On the second day after the operation the testing of instrumental conditioned reflex was resumed in both groups. Comparison of recovery periods for the ICR in both groups showed that recovery of the reflex and balancing hindlimb movements in melanin treated rats took place in three postoperative testing days, whereas in control group the recovery was not complete after 23 testing days. Electrophysiological study was conducted in 12 intact rats to show the effects of BM on the activity of SNc neurons. The firing rate of neurons was significantly increased by the BM injection. Morpho-histochemical study of brain sections was conducted after the completion of behavioral experiments. In melanin injected rats the study revealed absence of destruction or electrode trace in Substantia Nigra pars compacta of melanin injected rats. BM stimulates regeneration and microcirculation in SNc. Increased electrical activity of SN neurons and regenerative efforts induced by BM accelerate motor recovery after unilateral SNc destruction.

Effect of arbuscular mycorrhizal fungi on phytoextraction by corn (Zea mays) of lead-contaminated soil.

The role of arbuscular mycorrhizal fungi (AMF) in lead (Pb) uptake by corn (Zea mays) grown in soil supplemented with Pb was examined. Plants were subjected to four Pb levels: 0 (control); 10 (low); 100 (medium); and 500 mg L(-1) (high). At each Pb level, plants were grown in soil without and with fungicide (benomyl) (20 mg kg(-1)) to suppress AMF activity. Benomyl significantly reduced AMF colonization at high. medium, and zero Pb exposures. Benomyl application resulted in significantly lower concentrations of phosphorus in leaves at low and medium Pb exposures. The benomyl-treated plants had higher Pb and manganese concentrations in leaves than plants not treated with benomyl. In addition, benomyl-treated plants had generally lower concentrations of zinc and copper in leaves than plants not treated with benomyl. These results suggest that the role of AMF in heavy metal uptake is metal specific. Based on this work, the use of benomyl on soils contaminated with Pb can be recommended in phytoextraction.