Naturally Drug-Loaded Chitin: Isolation and Applications.

Naturally occurring three-dimensional (3D) biopolymer-based matrices that can be used in different biomedical applications are sustainable alternatives to various artificial 3D materials. For this purpose, chitin-based structures from marine sponges are very promising substitutes. Marine sponges from the order Verongiida (class Demospongiae) are typical examples of demosponges with well-developed chitinous skeletons. In particular, species belonging to the family Ianthellidae possess chitinous, flat, fan-like fibrous skeletons with a unique, microporous 3D architecture that makes them particularly interesting for applications. In this work, we focus our attention on the demosponge Ianthella flabelliformis (Linnaeus, 1759) for simultaneous extraction of both naturally occurring ("ready-to-use") chitin scaffolds, and biologically active bromotyrosines which are recognized as potential antibiotic, antitumor, and marine antifouling substances. We show that selected bromotyrosines are located within pigmental cells which, however, are localized within chitinous skeletal fibers of I. flabelliformis. A two-step reaction provides two products: treatment with methanol extracts the bromotyrosine compounds bastadin 25 and araplysillin-I N20 sulfamate, and a subsequent treatment with acetic acid and sodium hydroxide exposes the 3D chitinous scaffold. This scaffold is a mesh-like structure, which retains its capillary network, and its use as a potential drug delivery biomaterial was examined for the first time. The results demonstrate that sponge-derived chitin scaffolds, impregnated with decamethoxine, effectively inhibit growth of the human pathogen Staphylococcus aureus in an agar diffusion assay.

[Sanation of biliary system using antiseptic decasan in complex treatment of cholangitis].

Experience of treatment of 17 patients, suffering cholangitis of various genesis, using antiseptic Decasan, is presented. Clinical efficacy of the preparation in complex treatment of cholangitis, confirmed by results of the bile bacteriological investigation, was noted.

[Use of antiseptic dekasan in complex treatment of peritonitis].

Experience in treatment of 91 patients with peritonitis on various genesis using antiseptic Dekasan are presented. A marked clinical efficacy compared with that of other antiseptics in the complex treatment of peritonitis was noted.

[Application of decamethoxin solution in the treatment of surgical peritonitis].

Basing on analysis of results of clinical and experimental investigations, there was established, that application of the cationic antiseptics solution (including 0.02% solution of decametoxin) for the abdominal cavity sanation permits to reduce the microbal soiling while sanation performance and as well so on--the postoperative complications rate and mortality in surgical peritonitis.

[Application of antiseptic decasan in purulent infections of pararectal region].

The results of studying of antiseptic preparation Decasan for the treatment of patients, suffering purulent infections of pararectal region, are adduced. Efficacy of Decasan was analyzed in 102 patients. The results of investigation obtained are trusting hig antiseptic efficacy of preparation, witnessing possibility of its application as a preparation of choice for the treatment of patients, suffering purulent infections of pararectal region.

[Dekasan application in treatment of infected pancreatic necrosis and its complications].

The experience of the use of domestic antiseptic dekasan for topical use in patients over the infected pancreatic necrosis and its complications. There was significant improvement in the results of patients treatment.

[Application of antiseptic dekasan in urgent abdominal surgery].

Experience in local application of antiseptic Dekasan in the complex treatment of abdominal infections of various origins are presented. The clinical and economic efficacy of the drug application is notice.

Diverse inhibitory actions of quaternary ammonium cholinesterase inhibitors on Torpedo nicotinic ACh receptors transplanted to Xenopus oocytes.

BACKGROUND AND PURPOSE: This work was aimed at comparing and analysing the effects and mechanisms of action of the quaternary ammonium cholinesterase inhibitors (QChEIs) BW284c51, decamethonium and edrophonium, on nicotinic ACh receptor (nAChR) function. EXPERIMENTAL APPROACH: nAChRs purified from Torpedo electroplax were transplanted to oocytes and currents elicited by ACh (I(ACh)) either alone or in presence of these QChEIs were recorded. KEY RESULTS: None of the QChEIs, by itself, elicited changes in membrane conductance; however, when co-applied with ACh, all of them decreased I(ACh) in a concentration-dependent way. The mechanisms of nAChR inhibition were different for these QChEIs. BW284c51 blockade was non-competitive and voltage-dependent, although it also affected the n(H) of the dose-response curve. By contrast, decamethonium and edrophonium inhibition, at -60 mV, was apparently competitive and did not modify either desensitisation or n(H). Decamethonium effects were voltage-independent and washed out slowly after its removal; by contrast, edrophonium blockade had strong voltage dependence and its effects disappeared quickly after its withdrawal. Analysis of the voltage-dependent blockade indicated that BW284c51 bound to a shallow site into the channel pore, whereas edrophonium bound to a deeper locus. Accordingly, additive inhibitory effects on I(ACh) were found among any pairs of these QChEIs. CONCLUSIONS AND IMPLICATIONS: The tested QChEIs bound to the nAChR at several and different loci, which might account for their complex inhibitory behaviour, acting both as allosteric effectors and, in the case of BW284c51 and edrophonium, as open channel blockers.

Decamethonium bromide-mediated inhibition of embryonic muscle development.

This study determined the effect of decamethonium bromide (DMBr), a non-competitive blocker of the neuromuscular junction, on skeletal muscle development during chick embryogenesis. Decamethonium bromide caused generalized edema and high mortality with treated embryos rarely surviving beyond day 16 of incubation. Muscle degeneration was grossly evident on the muscles of abdomen, pectoral girdle, and leg. Semi-thin sections showed a high infiltration of macrophages in treated embryos and a massive degenerative process. Electron microscopy showed that both fast and slow fibers formed in the control and treated embryos, but those of the treated embryos failed to form myofibrils. Other organ systems, such as the heart and the gut, appeared histologically normal throughout the course of treatment. To investigate possible nerve independent action of DMBr on muscle development we determined the effect of this compound on the growth and differentiation of the C2C12 skeletal muscle cell line. DMBr treatment of C2C12 cell cultures did not affect the growth or survival of the cells, even at a tenfold higher concentration than that used in ovo, but myosin heavy chain expression was dramatically inhibited. We conclude that DMBr has a nerve independent blocking inhibition effect on myosin heavy chain synthesis in the developing avian embryo besides the recognized role as a non-competitive post-synaptic blocker of the neuromuscular junction.

Muscle and tendon size relationships in a paralyzed chick embryo model of clubfoot.

Clubfoot is a birth defect that may be related to muscle weakness or imbalance. The purpose of this study was to examine the relationships among muscle and tendon size and embryonic motility in a paralyzed chick embryo model of clubfoot and arthrogryposis. Decamethonium bromide, a neuromuscular blocking agent, was administered to a series of embryos in five dosage groups, producing a cohort of embryos with various degrees of paralysis and atrophy of tendons and muscle. Embryonic movement frequency was monitored, and after death in late gestation, the cross-sectional areas of the calf musculature and the gastrocnemius tendon proximal to the ankle were measured histologically. Significant correlations were found between embryonic motility and both muscle (r2 = 0.52) and tendon (r2 = 0.77) areas. In addition, a significant correlation (r2 = 0.74) was found between muscle and tendon areas, suggesting that a measurement of one may be used to predict the other.

NMDA as well as non-NMDA receptors mediate the neurotransmission of inspiratory drive to phrenic motoneurons in the adult rat.

The neurotransmission of bulbospinal respiratory drive is believed to involve primarily non-NMDA receptors located in the phrenic motonucleus (PMN). This conclusion is based on studies carried out mainly on in vitro brainstem-spinal cord preparations of the neonatal rat. The present study was undertaken to investigate the transmitter/receptor mechanisms in the PMN which are involved in the neurotransmission of inspiratory drive, using an in vivo adult rat model. Microinjections of glutamate, NMDA and AMPA into the PMN elicited an increase in the phrenic nerve (PN) background discharge. These injections did not alter significantly the frequency of spontaneously occurring PN bursts confirming that mechanisms responsible for respiratory rhythm reside in the supraspinal structures. Microinjections of an NMDA receptor blocker (AP-7), in concentrations that did not alter the responses to a non-NMDA receptor agonist (AMPA), reduced the PN amplitude significantly. Similarly, microinjections of a potent non-NMDA receptor blocker (NBQX), in concentrations that did not alter responses to NMDA, reduced the PN amplitude significantly. Sequential microinjections, within an interval of 5 min, of AP-7 and NBQX into the PMN, resulted in a dramatic reduction in the spontaneous PN bursts. The reduction of PN amplitude started immediately after the microinjection of AP-7 and NBQX, either alone or in combination, and reached a maximum within 5-10 min. These results indicate that, unlike in the neonatal rat, both NMDA and non-NMDA receptors located in the PMN play a significant role in the neurotransmission of the inspiratory drive in the adult rat.

[Use of decamethoxine in the complex treatment of chronic bronchitis]. / Primenenie dekametoksina v kompleksnom lechenii khronicheskogo bronkhita.

Seventy-two patients with chronic bronchitis were examined and divided into 3 groups. Group I consisted of patients with chronic catarrhal bronchitis (CCB) group II of those with chronic purulent bronchitis (CPB), group III of subjects with bronchitis associated with purulent destructive pulmonary diseases. All the patients received combined treatment with decamethoxin as an antibacterial modality. It was found that decamethoxin promotes elimination of the infection of the bronchial secretion in 60% of chronic bronchitis suffers, the incidence of microorganisms resistent to several antibiotics reduced 2-fold. Local use of decamethoxin as an antibacterial and antiinflammatory drug in multimodality treatment of chronic purulent bronchitis proved highly effective.