Search

Acinetobacter baumannii is a Gram-negative saprophytic rod inhabiting both moist niches and dry surfaces. The wide spread of the microbe in the environment by means of minimal nutritional requirements and exceptional survival capabilities give the opportunities to occupy hospital niches, and thus to create threats for hospitalized patients. This bacterium may be a part of the human microbiota as an opportunistic pathogen which upon the host’s weakening, causes less or more serious diseases. A. baumannii is an etiological factor of ventilator-associated pneumonia, which is especially dangerous for patients in intensive care units (in Poland every fifth patient suffers from such infection). Due to the increasing multidrug resistance of A. baumannii, this bacterium belongs to the group of priority pathogens. Fighting such dangerous bacteria is difficult due to their natural resistance as well as acquired resistance mechanisms in response to environmental threats. The unique ability of A. baumannii to cause diseases and acquire resistance to numerous antibiotics, make it necessary to control and prevent these infections.

Synthetic ionophores able to transport bicarbonate and chloride anions across lipid bilayers are appealing for their wide range of potential biological applications. We have studied the bicarbonate and chloride transport by carbazoles with two amido/thioamido groups using a bicarbonate-sensitive europium(III) probe in liposomes and found a highly remarkable concentration dependence. This can be explained by a combination of two distinct transport mechanisms: HCO3−/Cl− exchange and a combination of unassisted CO2 diffusion and HCl transport, of which the respective contributions were quantified. The compounds studied were found to be highly potent HCl transporters. Based on the mechanistic insights on anion transport, we have tested the antimicrobial activity of these compounds and found good correlation with their ion transport properties and a high activity against Gram-positive bacteria.

Wound management is the burning problem of modern medicine, significantly burdening developed countries’ healthcare systems. In recent years, it has become clear that the achievements of nanotechnology have introduced a new quality in wound healing. The application of nanomaterials in wound dressing significantly improves their properties and promotes the healing of injuries. Therefore, this review paper presents the subjectively selected nanomaterials used in wound dressings, including the metallic nanoparticles (NPs), and refers to the aspects of their application as antimicrobial factors. The literature review was supplemented with the results of our team’s research on the elements of multifunctional new-generation dressings containing nanoparticles. The wound healing multiple molecular pathways, mediating cell types, and affecting agents are discussed herein. Moreover, the categorization of wound dressings is presented. Additionally, some materials and membrane constructs applied in wound dressings are described. Finally, bacterial participation in wound healing and the mechanism of the antibacterial function of nanoparticles are considered. Membranes involving NPs as the bacteriostatic factors for improving wound healing of skin and bones, including our experimental findings, are discussed in the paper. In addition, some studies of our team concerning the selected bacterial strains’ interaction with material involving different metallic NPs, such as AuNPs, AgNPs, Fe3O4NPs, and CuNPs, are presented. Furthermore, nanoparticles’ influence on selected eukaryotic cells is mentioned. The ideal, universal wound dressing still has not been obtained; thus, a new generation of products have been developed, represented by the nanocomposite materials with antibacterial, anti-inflammatory properties that can influence the wound-healing process.

Laboratory investigations of an active vehicle suspension of an in-series structure of the slow-active type are presented in this paper. The multidimensional model is reduced to a case representing quarter car suspension. Control laws for active vibration reduction systems are usually determined based upon linear models of objects. Active suspensions are characterised by nonlinearity, connected most often with actuating systems and their energetic restrictions. This causes divergences between theoretical quality factors and those determined experimentally. The second essential problem is finding a compromise between opposed quality factors (for example, minimum power requirement and high efficiency of vibration reduction). Thanks to the use of the proper control law in the active vibration reduction system of vehicle suspension, the goal of ensuring a high level of ride comfort, good vehicle handling and incessant contact of the wheels with the road surface with a minimum power requirement may be attained. The authors, in seeking a compromise, determined classical LQR controllers for the proposed quality indicators realising the aims mentioned above. These controllers are determined for a linearised suspension model obtained from identification. Experimental characteristics are determined for all of the suspension control systems.

The aim of the study was to assess the effect of the prolonged intake of three beta-blocking drugs (propranolol, metoprolol and nebivolol) on the sexual behavior and penile microcirculation of rabbits. Drugs were administered p.o. for 9 weeks and every three weeks in each group (n=13) one subgroup (n=7) performed behavioral tests, whereas in the second subgroup (n=6) penile microcirculation was measured with a laser Doppler flowmeter. The copulation studies revealed significant impairment of sexual function only in the propranolol treated group. The measured behavioral parameters suggest that at a given dose propranolol affects more performance rather than arousal aspects of rabbits' sexual behavior. In the course of the whole study no significant difference was observed among groups in penile blood flow. The data indicate that among the beta-blockers given only propranolol interferes with sexual behavior, and that beta-blockers do not appear to have a negative effect on penile microcirculation.

In conclusion, we would like to emphasize that photodynamic therapy can be used as a convenient and promising tool in the treatment of various malignancies in the head and neck area. It has to be stressed that PDT is still less effective in the treatment of more advanced cases of head and neck cancer. As the method of treatment which improves the quality of life, its usefulness can be considered as well as palliative treatment of non-operative cases. Although the method is not free of several side effects, such skin phototoxicity, burning, slight pain and edema in the irradiated location. All these side effects are transient and usually they disappear within 24 hours. The photodynamic treatment always results in excellent cosmetic effects without scarring or marring which are usually encountered after routine surgical operation.

In the present study we have checked whether photodynamic therapy (PDT) may influence concentration of basic Fibroblast Growth Factor (bFGF) in in vivo conditions. We have implanted malignant tumor, i.e. BFS1 fibrosarcoma into BALB/c mice and have them treated using well established photosensitizer, hematoporphyrin derivative and new compound, hydroxygallium (III) phthalocyanine tetrasulfonic acid tetrasodium salt, BON-6. The administration of those compounds was followed by light irradiation using a halogen lamp at proper wavelengths. Our results indicate that in vivo photodynamic therapy may cause a significant decrease in bFGF concentration and this phenomenon is accompanied by prolongation of survival of treated animals.

Numerous studies have shown that lysosomal proteinases play an important role in carcinogenesis. The enzymatic activity of tumor-associated proteases is counter-balanced by specific inhibitors. Photodynamic therapy (PDT) is a technique which involves photoexcitation of sensitizing drugs retained in neoplastic tissue that is subsequently destroyed. Intraperitoneal injections of hematoporphyrin derivative (HpD) were given at a dose of 20 mg/kg in rats transplanted with mammary carcinoma. A halogen lamp was used 24 hours later at 630 +/- 20 nm and total dose--200 J/sq.cm. Cysteine proteinase inhibitor (CPI) was dissolved in saline and injected subcutaneously in doses of 50 mg and 200 mg per animal. The effectiveness of the treatment was evaluated with regard to survival time and tumor response and to depth of necrosis. In several cases tumors completely disappeared following HpD-PDT + CPI. The number of complete tumor responses was higher when PDT + 200 mg of CPI was used, i.e. 6 out of 10 rats. Promising results have also been obtained with regard to survival time of treated animals and to induction of tumor necrosis. We may presume that a combination of PDT and proteinase inhibitors could be a useful tool in further anticancer studies and, hopefully, in anticancer therapy.

Photodynamic therapy (PDT) has been used in the treatment of laryngeal lesions. The disorders comprised primary dysplasia and leukoplakia of the vocal cords. The patients after diagnosis were subjected to the therapy. Six hours prior to the light irradiation the patients received 4% solution of delta-aminolevulinic acid (ALA) during 30 minutes inhalation. After 6 hours all the changes were irradiated using 400 nm wavelength light from 300 W halogen lamp (range: 380-420 nm) in order to visualize them. Next, the wavelength was tuned to 650 nm (range 620-680 nm) and the total dose 120 J/cm2 for all cases. Control examinations in patients revealed complete response of the lesions within 2-3 months after PDT.