The use of 4-Hexylresorcinol as antibiotic adjuvant.

Ever decreasing efficiency of antibiotic treatment due to growing antibiotic resistance of pathogenic bacteria is a critical issue in clinical practice. The two generally accepted major approaches to this problem are the search for new antibiotics and the development of antibiotic adjuvants to enhance the antimicrobial activity of known compounds. It was therefore the aim of the present study to test whether alkylresorcinols, a class of phenolic lipids, can be used as adjuvants to potentiate the effect of various classes of antibiotics. Alkylresorcinols were combined with 12 clinically used antibiotics. Growth-inhibiting activity against a broad range of pro- and eukaryotic microorganisms was determined. Test organisms did comprise 10 bacterial and 2 fungal collection strains, including E. coli and S. aureus, and clinical isolates of K. pneumoniae. The highest adjuvant activity was observed in the case of 4-hexylresorcinol (4-HR), a natural compound found in plants with antimicrobial activity. 50% of the minimal inhibitory concentration (MIC) of 4-HR caused an up to 50-fold decrease in the MIC of antibiotics of various classes. Application of 4-HR as an adjuvant revealed its efficiency against germination of bacterial dormant forms (spores) and prevented formation of antibiotic-tolerant persister cells. Using an in vivo mouse model of K. pneumoniae-induced sepsis, we could demonstrate that the combination of 4-HR and polymyxin was highly effective. 75% of animals were free of infection after treatment as compared to none of the animals receiving the antibiotic alone. We conclude that alkylresorcinols such as 4-HR can be used as an adjuvant to increase the efficiency of several known antibiotics. We suggest that by this approach the risk for development of genetically determined antibiotic resistance can be minimized due to the multimodal mode of action of 4-HR.

Association of Arterial Hypertension with Hepatobiliary Pathology: The Occurrence of Comorbidity and Features of Metabolic Processes.

Comorbidity of hypertension and hepatobiliary pathology has negative medical and social consequences, including an increase in the indicators of hospital admissions, disability and mortality. OBJECTIVE: The aim was to study the occurrence of hypertension combined with hepatobiliary diseases depending on social status, gender and age in 2003-2017 and their influence on indicators of metabolic processes in patients with a therapeutic profile. METHODS: A cross-sectional study using the inpatients' medical record database of the clinic of Federal Research Centre for Basic and Translational Medicine (Novosibirsk, Russia), which collects demographics, diagnoses (using ICD-10 codes), procedures and examinations of all inpatients from 2003-2017 was conducted. The incidence of comorbidity of hypertension and hepatobiliary pathology depending on age, gender and social status, based on the analysis of 13496 medical records was examined. A comparative analysis of biochemical parameters characterizing the main types of metabolism (lipid, protein, carbohydrate and purine) was carried out in 3 groups of patients: with hypertension; with hepatobiliary pathology, and with a combined pathology. RESULTS: During the years 2003-2005, there was the greatest frequency of this comorbidity in workers, in women, in the age group 60 years and older. In 2009-2017, the highest incidence was observed in the male administrative staff. In patients with this comorbidity, more pronounced changes in carbohydrate, protein, lipid and purine metabolism were found in comparison with groups of patients with isolated diseases. CONCLUSION: The results highlight the need to improve the system of prevention and treatment of comorbidity taking into account sex, age, occupation and features of metabolism.

[Combined rehabilitation in the patients presenting with dorsopathies of the lumbar spine and concomitant irritable bowel syndrome based at a therapeutic clinic].

BACKGROUND: Comorbidity constitutes a serious challenge for rehabilitative medicine. The comorbidity of the dorsopathy of the lumbar spine and irritable bowel syndrome mutually complicates the clinical course of both conditions, significantly reduces the patients' quality of life. and increases the costs of diagnostic procedures and restoration of the working capacity. The approaches to the non-pharmacological management of the patients presenting with these diseases remain to be developed. AIMS: The objective of the present study was to evaluate the effectiveness of the proposed combined non-medicinal rehabilitation modality which included a course of therapy with the application of modulated sinusoidal currents, total wrappings with the use of a Rapan saline solution, and sedative inhalations additionally introduced into the basic medicinal therapy of the patients presenting with dorsopathy of the lumbar spine combined with irritable bowel syndrome in the stationary phase. MATERIALS AND METHODS: A total of 59 patients at the age from 20 to 65 years suffering from dorsopathy of the lumbar spine and concomitant irritable bowel syndrome were examined and treated. All the patients were randomized into two groups, the main (n=21) and control (n=38) one, matched for the sex and age. The patients in the control group received the conventional medical treatment in accordance with the adopted medical and economic standards during 2 weeks. The patients of the main group received, in addition to the basal medicinal therapy, the proposed combined rehabilitative physiotherapeutic treatment that included a course of therapy with modulated sinusoidal currents, total wrapping with the use of a Rapan saline solution, and sedative inhalations of the of peony root extract. The effectiveness of these rehabilitation modalities was monitored before and after the course of therapy based on the estimation of bowel function dynamics, the severity of pain syndrome, and the patient's quality of life in terms of the health status with the use of the SF-36 questionnaire. RESULTS: The therapeutic and rehabilitative procedures resulted in a well apparent improvement of the genera condition in the patients of the main group associated with a greater degree of reduction of the incidence of specific clinical symptoms, more rapid relief of the pain syndrome, and a more pronounced improvement of the quality of life indices in comparison with the same variables in the patients comprising the control group. After the course of the treatment and rehabilitation, the incidence of spinal pain in the patients of the main group was significantly reduced by 87% (p=0.001) compared with those of the control group (32%; p=0.005). The frequency of abdominal pain decreased in the main group by 47% (p=0.021) versus the control group (by 27%; p=0.007). The quality of life indices increased 1.2 times in the main group but remained unaltered in the control group. DISCUSSION: The patients of the main group exhibited a more pronounced than in the control group positive dynamics of health conditions characterized by a well apparent reduction in the incidence of the major clinical symptoms of the disease, faster alleviation of the pain syndrome, and the marked improvement of the quality of life indices. CONCLUSIONS: The results of the study with the inclusion of therapy with modulated sinusoidal currents together with total wrapping using the Rapan saline solution and sedative inhalations into the program of the combined treatment of the patients presenting with dorsopathy of the lumbar spine and concomitant irritable bowel syndrome provide a basis for recommending this physiotherapeutic modality for personalized rehabilitation of this group of patients under conditions of a therapeutic clinic.

Adding dimension to cellular mechanotransduction: Advances in biomedical engineering of multiaxial cell-stretch systems and their application to cardiovascular biomechanics and mechano-signaling.

Hollow organs (e.g. heart) experience pressure-induced mechanical wall stress sensed by molecular mechano-biosensors, including mechanosensitive ion channels, to translate into intracellular signaling. For direct mechanistic studies, stretch devices to apply defined extensions to cells adhered to elastomeric membranes have stimulated mechanotransduction research. However, most engineered systems only exploit unilateral cellular stretch. In addition, it is often taken for granted that stretch applied by hardware translates 1:1 to the cell membrane. However, the latter crucially depends on the tightness of the cell-substrate junction by focal adhesion complexes and is often not calibrated for. In the heart, (increased) hemodynamic volume/pressure load is associated with (increased) multiaxial wall tension, stretching individual cardiomyocytes in multiple directions. To adequately study cellular models of chronic organ distension on a cellular level, biomedical engineering faces challenges to implement multiaxial cell stretch systems that allow observing cell reactions to stretch during live-cell imaging, and to calibrate for hardware-to-cell membrane stretch translation. Here, we review mechanotransduction, cell stretch technologies from uni-to multiaxial designs in cardio-vascular research, and the importance of the stretch substrate-cell membrane junction. We also present new results using our IsoStretcher to demonstrate mechanosensitivity of Piezo1 in HEK293 cells and stretch-induced Ca2+ entry in 3D-hydrogel-embedded cardiomyocytes.

Lipid-protein interactions: Lessons learned from stress.

Biological membranes are essential for normal function and regulation of cells, forming a physical barrier between extracellular and intracellular space and cellular compartments. These physical barriers are subject to mechanical stresses. As a consequence, nature has developed proteins that are able to transpose mechanical stimuli into meaningful intracellular signals. These proteins, termed Mechanosensitive (MS) proteins provide a variety of roles in response to these stimuli. In prokaryotes these proteins form transmembrane spanning channels that function as osmotically activated nanovalves to prevent cell lysis by hypoosmotic shock. In eukaryotes, the function of MS proteins is more diverse and includes physiological processes such as touch, pain and hearing. The transmembrane portion of these channels is influenced by the physical properties such as charge, shape, thickness and stiffness of the lipid bilayer surrounding it, as well as the bilayer pressure profile. In this review we provide an overview of the progress to date on advances in our understanding of the intimate biophysical and chemical interactions between the lipid bilayer and mechanosensitive membrane channels, focusing on current progress in both eukaryotic and prokaryotic systems. These advances are of importance due to the increasing evidence of the role the MS channels play in disease, such as xerocytosis, muscular dystrophy and cardiac hypertrophy. Moreover, insights gained from lipid-protein interactions of MS channels are likely relevant not only to this class of membrane proteins, but other bilayer embedded proteins as well. This article is part of a Special Issue entitled: Lipid-protein interactions.

Aerobic biological treatment of thermophilically digested sludge.

Aerobic biological treatment of digested sludge was studied in a continuously operated laboratory set-up. An aerated reactor was filled with thermophilically digested sludge from the Moscow wastewater treatment plant and inoculated with special activated sludge. It was then operated at the chemostat mode at different flow rates. Processes of nitrification and denitrification, as well as dephosphatation, occurred simultaneously during biological aerobic treatment of thermophilically digested sludge. Under optimal conditions, organic matter degradation was 9.6%, the concentrations of ammonium nitrogen and phosphate decreased by 89 and 83%, respectively, while COD decreased by 12%. Dewaterability of digested sludge improved significantly. The processes were found to depend on hydraulic retention time, oxygen regime, and temperature. The optimal conditions were as follows: hydraulic retention time 3-4 days, temperature 30-35 degrees C, dissolved oxygen levels 0.2-0.5 mg/L at continuous aeration or 0.7-1 mg/L at intermittent aeration. Based on these findings, we propose a new combined technology of wastewater sludge treatment. The technology combines two stages: anaerobic digestion followed by aerobic biological treatment of digested sludge. The proposed technology makes it possible to degrade the sludge with conversion of approximately 45% volatile suspended solids to biogas, to improve nitrogen and phosphorus removal in reject water from sludge treatment units, and to achieve removal of malodorous substances after 8-9 days of anaerobic-aerobic sludge treatment.

Identification of a 28 kDa secretory protein from rat olfactory epithelium as a thiol-specific antioxidant.

The 28 kDa secretory protein is one of the abundant water-soluble proteins in olfactory epithelium of mammals. Analysis of partial amino acid sequence of the 28 kDa protein strongly suggested that it belongs to a new family of highly conserved antioxidant proteins requiring thiol for their antioxidant activity (TSA/AhpC family). In the present study, we found the 28 kDa protein to have thiol-dependent antioxidant activity, thereby protecting radical-sensitive proteins such as glutamine synthetase and hemoglobin from oxidative modification caused by thiol-dependent metal ion-catalyzed oxidation system. The purified 28 kDa protein did not possess catalase or glutathione peroxidase activities, and required thiols to exhibit its antioxidant activity. The 28 kDa protein is the first member of the family of thiol-specific antioxidants identified in olfactory epithelium and the first secretory protein shown to be thiol-specific antioxidant.

Importance of RpoS and Dps in survival of exposure of both exponential- and stationary-phase Escherichia coli cells to the electrophile N-ethylmaleimide.

The mechanisms by which Escherichia coli cells survive exposure to the toxic electrophile N-ethylmaleimide (NEM) have been investigated. Stationary-phase E. coli cells were more resistant to NEM than exponential-phase cells. The KefB and KefC systems were found to play an important role in protecting both exponential- and stationary-phase cells against NEM. Additionally, RpoS and the DNA-binding protein Dps aided the survival of both exponential- and stationary-phase cells against NEM. Double mutants lacking both RpoS and Dps and triple mutants deficient in KefB and KefC and either RpoS or Dps had an increased sensitivity to NEM in both exponential- and stationary-phase cells compared to mutants missing only one of these protective mechanisms. Stationary- and exponential-phase cells of a quadruple mutant lacking all four protective systems displayed even greater sensitivity to NEM. These results indicated that protection by the KefB and KefC systems, RpoS and Dps can each occur independently of the other systems. Alterations in the level of RpoS in exponentially growing cells correlated with the degree of NEM sensitivity. Decreasing the level of RpoS by enriching the growth medium enhanced sensitivity to NEM, whereas a mutant lacking the ClpP protease accumulated RpoS and gained high levels of resistance to NEM. A slower-growing E. coli strain was also found to accumulate RpoS and had enhanced resistance to NEM. These data emphasize the multiplicity of pathways involved in protecting E. coli cells against NEM.

Survival of Escherichia coli cells exposed to iodoacetate and chlorodinitrobenzene is independent of the glutathione-gated K+ efflux systems KefB and KefC.

The KefB and KefC systems of Escherichia coli cells are activated by iodoacetate (IOA) and chlorodinitrobenzene (CDNB), leading to a rapid drop in the intracellular pH. However, survival of exposure to IOA or CDNB was found to be essentially independent of KefB and KefC activation. No correlation was found between the toxicity of the compound and its ability to elicit protective acidification via activation of KefB and KefC.

Survival during exposure to the electrophilic reagent N-ethylmaleimide in Escherichia coli: role of KefB and KefC potassium channels.

The role of the KefB and KefC potassium efflux systems in protecting Escherichia coli cells against the toxic effects of the electrophile N-ethylmaleimide has been investigated. Activation of KefB and KefC aids the survival of cells exposed to high concentrations (> 100 microM) of NEM. High potassium concentrations reduce the protection afforded by activation of KefB and KefC, but the possession of these systems is still important under these conditions. The Kdp system, which confers sensitivity to the electrophile methylglyoxal, did not affect the survival of cells exposed to NEM. Survival is correlated with the reduction of the cytoplasmic pH upon activation of the channels. In particular, the kinetics of the intracellular pH (pHi) change are crucial to the retention of viability of cells exposed to NEM; slow acidification does not protect cells as effectively as rapid lowering of pHi. Cells treated with low levels of NEM (10 microM) recover faster if they activate KefB and KefC, and this correlates with changes in pHi. The pHi does not significantly alter the rate of NEM metabolism. The possible mechanisms by which protection against the electrophile is mediated are discussed.