Edgaras Stankevičius

Public Knowledge, Beliefs and Behavior on Antibiotic Use and Self-Medication in Lithuania

Irrational antibiotic use has led society to antibiotic resistance—a serious health problem worldwide. This study aimed to assess public knowledge, beliefs, and behavior concerning antibiotic use and self-medication in Lithuania. The cross-sectional survey method was processed using a validated questionnaire in different regions of Lithuania. In total, 1005 adults completed the questionnaire and were included in the study. More than half of the respondents (61.1%) had poor knowledge of antibiotics. Almost half of the respondents incorrectly identified antibiotics as being effective either against viral (26.0%) or mixed (bacterial and viral) infections (21.7%). The respondents with lower educational qualifications (OR = 2.515; 95% CI 1.464–4.319; p = 0.001) and those from rural areas (OR = 1.765; 95% CI 1.041–2.991; p = 0.035) were significantly less knowledgeable of antibiotics. There was no significant difference between genders, different age groups, or different parenthood status. The determined level of self–medication with antibiotics was 31.0%. The men (OR = 1.650; 95% CI 1.120–2.430; p = 0.011), the respondents from rural areas (OR = 2.002; 95% CI 1.343–2.985; p = 0.001), and those without children (OR = 2.428; 95% CI 1.477–3.991; p < 0.001) were more likely to use antibiotics in self-medication. Lithuanian residents’ knowledge of antibiotics is insufficient. More information about antibiotic use should be provided by physicians and pharmacists. Self-medication with antibiotics is a serious problem in Lithuania and requires considerable attention.

Non-endothelial endothelin counteracts hypoxic vasodilation in porcine large coronary arteries

BackgroundThe systemic vascular response to hypoxia is vasodilation. However, reports suggest that the potent vasoconstrictor endothelin-1 (ET-1) is released from the vasculature during hypoxia. ET-1 is reported to augment superoxide anion generation and may counteract nitric oxide (NO) vasodilation. Moreover, ET-1 was proposed to contribute to increased vascular resistance in heart failure by increasing the production of asymmetric dimethylarginine (ADMA). We investigated the role of ET-1, the NO pathway, the potassium channels and radical oxygen species in hypoxia-induced vasodilation of large coronary arteries.ResultsIn prostaglandin F2α (PGF2α, 10 μM)-contracted segments with endothelium, gradual lowering of oxygen tension from 95 to 1% O2 resulted in vasodilation. The vasodilation to O2 lowering was rightward shifted in segments without endothelium at all O2 concentrations except at 1% O2. The endothelin receptor antagonist SB217242 (10 μM) markedly increased hypoxic dilation despite the free tissue ET-1 concentration in the arterial wall was unchanged in 1% O2 versus 95% O2. Exogenous ET-1 reversed hypoxic dilation in segments with and without endothelium, and the hypoxic arteries showed an increased sensitivity towards ET-1 compared to the normoxic controls. Without affecting basal NO, hypoxia increased NO concentration in PGF2α-contracted arteries, and an NO synthase inhibitor, L-NOARG,(300 μM, NG-nitro-L-Arginine) reduced hypoxic vasodilation. NO-induced vasodilation was reduced in endothelin-contracted preparations. Arterial wall ADMA concentrations were unchanged by hypoxia. Blocking of potassium channels with TEA (tetraethylammounium chloride)(10 μM) inhibited vasodilation to O2 lowering as well as to NO. The superoxide scavenger tiron (10 μM) and the putative NADPH oxidase inhibitor apocynin (10 μM) leftward shifted concentration-response curves for O2 lowering without changing vasodilation to 1% O2. PEG (polyethylene glycol) catalase (300 u/ml) inhibited H2O2 vasodilation, but failed to affect vasodilation to O2 lowering. Neither did PEG-SOD (polyethylene glycol superoxide dismutase)(70 u/ml) affect vasodilation to O2 lowering. The mitochondrial inhibitors rotenone (1 μM) and antimycin A (1 μM) both inhibited hypoxic vasodilatation.ConclusionThe present results in porcine coronary arteries suggest NO contributes to hypoxic vasodilation, probably through K channel opening, which is reversed by addition of ET-1 and enhanced by endothelin receptor antagonism. These latter findings suggest that endothelin receptor activation counteracts hypoxic vasodilation.

Evaluation of hydration status calculated from differences in venous and capillary plasma dilution during stepwise crystalloid infusions: A randomized crossover study in healthy volunteers

BACKGROUND AND OBJECTIVE A mini volume loading test (mVLT) was proposed for estimating hydration status and interstitial fluid accumulation during stepwise infusion of crystalloids. The method is based on both the transcapillary reflux model and the hypothesis that when subjects are dehydrated, venous plasma dilution induced by a fluid challenge is higher than in the capillaries, and that difference is diminished when the fluid challenge is given to more hydrated individuals. Our objective was to test that hypothesis by evaluating the veno-capillary dilution difference during mVLT in subjects with different hydration status. MATERIALS AND METHODS In a prospective randomized crossover study, three mini fluid challenges were given to 12 healthy volunteers on two occasions. The subjects were either dehydrated or hydrated before the experiments. RESULTS In dehydrated subjects only, capillary plasma dilution was significantly lower than venous (P=0.015, 0.005 and 0.006) after each mini fluid challenge. CONCLUSIONS Veno-capillary dilution difference during mVLT depends on the hydration status. The mVLT method could possibly discriminate between the different states of hydration.

Src family protein tyrosine kinases modulate L-type calcium current in human atrial myocytes.

In the heart, L-type voltage dependent calcium channels (L-VDCC) provide Ca(2+) for the activation of contractile apparatus. The best described pathway for L-type Ca(2+) current (I(Ca,L)) modulation is the phosphorylation of calcium channels by cAMP-dependent protein kinase A (PKA), the activity of which is predominantly regulated in opposite manner by β-adrenergic (β-ARs) and muscarinic receptors. The role of other kinases is controversial and often depends on tissues and species used in the studies. In different studies the inhibitors of tyrosine kinases have been shown either to stimulate or inhibit, or even have a biphasic effect on I(Ca,L). Moreover, there is no clear picture about the route of activation and the site of action of cardiac Src family nonreceptor tyrosine kinases (Src-nPTKs). In the present study we used PP1, a selective inhibitor of Src-nPTKs, alone and together with different activators of I(Ca,L), and demonstrated that in human atrial myocytes (HAMs): (i) Src-nPTKs are activated concomitantly with activation of cAMP-signaling cascade; (ii) Src-nPTKs attenuate PKA-dependent stimulation of I(Ca,L) by inhibiting PKA activity; (iii) Gα(s) are not involved in the direct activation of Src-nPTKs. In this way, Src-nPTKs may provide a protecting mechanism against myocardial overload under conditions of increased sympathetic activity.

Femtosecond laser micro‐machined polyimide films for cell scaffold applications

Engineering of sophisticated synthetic 3D scaffolds that allow controlling behaviour and location of the cells requires advanced micro/nano‐fabrication techniques. Ultrafast laser micro‐machining employing a 1030‐nm wavelength Yb:KGW femtosecond laser and a micro‐fabrication workstation for micro‐machining of commercially available 12.7 and 25.4 μm thickness polyimide (PI) film was applied. Mechanical properties of the fabricated scaffolds, i.e. arrays of differently spaced holes, were examined via custom‐built uniaxial micro‐tensile testing and finite element method simulations. We demonstrate that experimental micro‐tensile testing results could be numerically simulated and explained by two‐material model, assuming that 2–6 μm width rings around the holes possessed up to five times higher Youngs modulus and yield stress compared with the rest of the laser intacted PI film areas of ‘dog‐bone’‐shaped specimens. That was attributed to material modification around the micro‐machined holes in the vicinity of the position of the focused laser beam track during trepanning drilling. We demonstrate that virgin PI films provide a suitable environment for the mobility, proliferation and intercellular communication of human bone marrow mesenchymal stem cells, and discuss how cell behaviour varies on the micro‐machined PI films with holes of different diameters (3.1, 8.4 and 16.7 μm) and hole spacing (30, 35, 40 and 45 μm). We conclude that the holes of 3.1 μm diameter were sufficient for metabolic and genetic communication through membranous tunneling tubes between cells residing on the opposite sides of PI film, but prevented the trans‐migration of cells through the holes. Copyright

A mini volume loading test for indication of preoperative dehydration in surgical patients.

BACKGROUND AND OBJECTIVE Previously, a mini volume loading test (mVLT) detected signs of dehydration in healthy volunteers after an overnight fast. Our objective was to investigate whether mVLT could indicate preoperative dehydration in patients after an overnight fast. MATERIALS AND METHODS The mVLT was performed in 36 elective primary total knee arthroplasty patients. Each subject received three fluid challenges before anesthesia induction. These consisted of 5 mL/kg boluses of Ringers acetate infused over 3-5 min and followed by a 5-min period without fluids. Invasive (arterial, venous) and noninvasive (capillary) measurements of hemoglobin concentration were performed before and after each fluid challenge, as well as after a 20-min period without fluids which followed the last bolus. Arterial, venous and capillary plasma dilutions were calculated in every data point. Dilution values were used to calculate the plasma dilution efficacy of each fluid challenge. RESULTS Venous dilution was higher than capillary after the first fluid challenge (P=0.030), but lower than capillary after 20 min period following the last bolus (P=0.009). Arterial dilution was lower than capillary (P=0.005) after 20 min following the last bolus. Veno-capillary and arterio-capillary plasma dilution efficacy differences decreased (P=0.004 and P=0.033, respectively) from positive to negative during mVLT. These are signs of re-hydration from pre-existing dehydration according to a transcapillary reflux model. CONCLUSIONS Signs of dehydration were observed during mVLT in patients after pre-operative overnight fast. A revised transcapillary reflux model was proposed to explain the results.

Hyperthermia Differently Affects Connexin43 Expression and Gap Junction Permeability in Skeletal Myoblasts and HeLa Cells

Stress kinases can be activated by hyperthermia and modify the expression level and properties of membranous and intercellular channels. We examined the role of c-Jun NH2-terminal kinase (JNK) in hyperthermia-induced changes of connexin43 (Cx43) expression and permeability of Cx43 gap junctions (GJs) in the rabbit skeletal myoblasts (SkMs) and Cx43-EGFP transfected HeLa cells. Hyperthermia (42°C for 6 h) enhanced the activity of JNK and its target, the transcription factor c-Jun, in both SkMs and HeLa cells. In SkMs, hyperthermia caused a 3.2-fold increase in the total Cx43 protein level and enhanced the efficacy of GJ intercellular communication (GJIC). In striking contrast, hyperthermia reduced the total amount of Cx43 protein, the number of Cx43 channels in GJ plaques, the density of hemichannels in the cell membranes, and the efficiency of GJIC in HeLa cells. Both in SkMs and HeLa cells, these changes could be prevented by XG-102, a JNK inhibitor. In HeLa cells, the changes in Cx43 expression and GJIC under hyperthermic conditions were accompanied by JNK-dependent disorganization of actin cytoskeleton stress fibers while in SkMs, the actin cytoskeleton remained intact. These findings provide an attractive model to identify the regulatory players within signalosomes, which determine the cell-dependent outcomes of hyperthermia.

Scaffold design for artificial tissue with bone marrow stem cells

OBJECTIVE The aim of this study was to test polymeric materials (collagen, fibrin, polyimide film, and polylactic acid) for single- and multi-layer scaffold formation. MATERIALS AND METHODS In our study, we used rabbit bone marrow stem cells (rBMSCs) and human mesenchymal stem cells (hMSCs) with materials of a different origin for the formation of an artificial scaffold, such as a collagen scaffold, fibrin scaffold produced from clotted rabbit plasma, electrospun poly(lactic acid) (PLA) mats, polyimide film (PI), and the combination of the latter two. Cell imaging was performed 3-14 days after cell cultivation in the scaffolds. Time-lapse imaging was used to determine hMSC mobility on the PI film. RESULTS Cell incorporation in collagen and clotted fibrin scaffolds was evaluated after 2-week cultivation in vitro. Histological analysis showed that cells penetrated only external layers of the collagen scaffold, while the fibrin clot was populated with rBMSCs through the entire scaffold thickness. As well, cell behavior on the laser micro-structured PI film was analyzed. The mobility of hMSCs on the smooth PI film and the micro-machined surface was 20±2μm/h and 18±4μm/h, respectively. After 3-day cultivation, hMSCs were capable of spreading through the whole 100±10μm-thick layer of the electrospun PLA scaffold and demonstrated that the multilayer scaffold composed of PI and PLA materials ensured a suitable environment for cell growth. CONCLUSIONS The obtained results suggest that electrospinning technology and femtosecond laser micro-structuring could be employed for the development of multi-layer scaffolds. Different biopolymers, such as PLA, fibrin, and collagen, could be used as appropriate environments for cell inhabitation and as an inner layer of the multi-layer scaffold. PI could be suitable as a barrier blocking cell migration from the scaffold. However, additional studies are needed to determine optimal parameters of inner and outer scaffold layers.

Impedance plethysmography as an alternative method for the diagnosis of peripheral arterial disease.

BACKGROUND AND OBJECTIVE In the diagnosis of peripheral artery disease (PAD), the ankle-brachial index (ABI) is considered as the standard, and other noninvasive methods have received too little attention. Therefore, the aim of the study was to determine the diagnostic accuracy of impedance plethysmography in diagnosing PAD and to compare this method with other methods. MATERIALS AND METHODS A total of 66 patients with a mean age of 76.1±9.6 years who had been treated for various cardiovascular diseases at Kaunas Clinical Hospital during 2011-2012 were enrolled into the study. All the patients were screened for PAD. Impedance plethysmography was performed with a new-generation Niccomo™ device. The receiver operating characteristic analysis was employed to determine the diagnostic accuracy of 4 parameters of impedance plethysmography: crest time (CT), crest width (CW), pulse amplitude (Pampl), and alternating blood flow (ABF). RESULTS There were a significant correlation between the ABI and the CT (r=-0.699, P<0.001), between the ABI and the ABF (r=0.552; P<0.001), and between the ABI and the Pampl only among men (r=0.652; P<0001). No correlation was found between the ABI and the CW. Among all the parameters, the CT had the highest sensitivity and specificity (73.2% and 96.0%, respectively). Other parameters had the following sensitivities and specificities: ABF, 61.0% and 96.0%; and Pampl, 90.0% and 20.0%, respectively. CONCLUSIONS Impedance plethysmography, especially its parameter CT, is an alternative noninvasive method in diagnosing PAD and could be used for the screening of patients with PAD.

Response inhibition, set shifting, and complex executive function in patients with chronic lower back pain

OBJECTIVE The aim of our study was to evaluate how response inhibition, set shifting, and complex executive function (represented by risky decision-making) are altered in chronic lower back pain patients. MATERIALS AND METHODS A total of 29 patients with chronic lower back pain (CLBP >6 months) aged 49-69 years and 30 healthy volunteers matched for age, gender, and education were enrolled in a case-control study. The study was conducted in the Departments of Neurology and Neurosurgery of Panevėžys Regional Hospital, Lithuania. Pain was evaluated by the visual analog scale, Pakula Pain Questionnaire (Lithuanian analog of McGill Pain Questionnaire), and Fibromyalgia Tender Points Examination. A battery of neuropsychological tests used included Stroop Test Victoria version, Trail Making Test parts A and B, and Game of Dice Task (GDT). RESULTS CLBP patients did not score significantly worse in any examined neuropsychological tests. Response Inhibition correlated inversely with number of tender points in CLBP patients. GDT performance showed no significant difference in net score (number of safe minus risky decisions). Unexpectedly, both groups favored risky decisions. CONCLUSIONS We found no statistically significant difference in response inhibition, set shifting, or complex executive function between CLBP patients and healthy older adults. Moreover, a risky decision-making pattern found in the Lithuanian population may underscore the importance of cultural context when examining complex executive function. However, further studies are needed to prove this point.