Electrochemical measurements of the levels of nitric oxide metabolites in the blood serum

Background: Sepsis is a serious clinical condition caused by a dysregulated immune response to infection resulting in multiple organ failure. In the pathogenesis of sepsis, especially that of septic shock, great importance is given to the endothelial marker of vascular regulation, nitric oxide (NO). In septic shock, dysregulation of the vascular tone plays a key role in the development of hypotension. Therefore, the control of the level of nitric oxide and its stable metabolites in critically ill patients is a very important task. Aim: the aim of this study was to evaluate the potential of the electrochemical nitrite detection in the patients blood serum. Methods: The levels of nitric oxide stable metabolites in the blood serum of healthy individuals (n=20) and septic patients (n=25) were studied by the electrochemical method using a composite electrode and by the spectrophotometric method using the Griess reagent. Results: The data in the groups of healthy people and patients with sepsis differ significantly (p 0.00001) both when measured using electrochemical and spectrophotometric methods. The median value of the current response in healthy people was 0.41 A (0.33; 0.55), and the total content of nitric oxide metabolites (NOx) was 26.8 mol/L (20.8; 31.0), while in patients with sepsis, these values were 0.79 A (0.61; 1.28) and 38.89 mol/L (29.64; 57.45), respectively. A negative correlation was found between the data obtained for practically healthy persons (r=-0.696, p=0.0007). Conclusion: The obtained results allow us to conclude that the nitrite measurement in the blood serum by amperometry using a composite electrode is promising as a diagnostic technique

Clinical and pathophysiologic aspects of ECMO-associated hemorrhagic complications

Extracorporeal membrane oxygenation (ECMO) is increasingly used to treat severe cases of acute respiratory or cardiac failure. Hemorrhagic complications represent one of the most common complications during ECMO, and can be life threatening. The purpose of this study was to elucidate pathophysiological mechanisms of ECMO-associated hemorrhagic complications and their impact on standard and viscoelastic coagulation tests. The study cohort included 27 patients treated with VV-ECMO or VA-ECMO. Hemostasis was evaluated using standard coagulation tests and viscoelastic parameters investigated with rotational thromboelastometry. Anticoagulation and hemorrhagic complications were analyzed for up to seven days depending on ECMO duration. Hemorrhagic complications developed in 16 (59%) patients. There were 102 discrete hemorrhagic episodes among 116 24-hour-intervals, of which 27% were considered to be clinically significant. The highest number of ECMO-associated hemorrhages occurred on the 2(nd)and 3(rd)day of treatment. Respiratory tract bleeding was the most common hemorrhagic complication, occurring in 62% of the 24-hour intervals. All 24-hours-intervals were divided into two groups: "with bleeding" and "without bleeding". The probability of hemorrhage was significantly associated with abnormalities of four parameters: increased international normalized ratio (INR, sensitivity 71%, specificity 94%), increased prothrombin time (PT, sensitivity 90%, specificity 72%), decreased intrinsic pathway maximal clot firmness (MCFin, sensitivity 76%, specificity 89%), and increased extrinsic pathway clot formation time (CFTex, sensitivity 77%, specificity 87%). In conclusions, early ECMO-associated hemorrhagic complications are related to one traditional and two novel viscoelastic coagulation abnormalities: PT/INR elevation, reduced maximum clot firmness due to intrinsic pathway dysfunction (MCFin), and prolonged clot formation time due to extrinsic pathway dysfunction (CFTex). When managing hemostasis during ECMO, derangements in PT/INR, MCFin and CFT(ex)should be focused on

Neurological disorders in patients with acute thallium poisoning

The largest study on neurological disorders in patients with laboratory-confirmed acute thallium poisoning was conducted in State Budgetary Healthcare Institution N.V.Sklifosovsky Research Institute of Emergency Medicine of Moscow Department of Health Care. For the first time affected patients were matched by route of poison exposure, time and severity of poisoning, and age. Neurological disorders as well as other symptoms typical for acute thallium poisoning are presented. Incidence of all symptoms and their severity depending on toxic agent concentration in biological liquids are presented. Thallium poisoning should be suspected if such symptoms as alopecia, myalgia of different localization (predominantly in chest and proximal leg muscles), peripheral paraparesis or tetraparesis, sensory polyneuropathy presenting with paresthesia accompanied by pain and/or hypesthesia transforming to mononeuropathy, coordination impairment presented by static or dynamic ataxia, and postural tremor coexist. Thallium determination in blood and urine is an informative diagnostic test. Pain, motor and coordination disturbances are first to regress, and tremor, sensory, cognitive and emotional disturbances preserve for a longer time. Polyneuropathies transform to mononeuropathies in time. Tremor can get worse despite thallium concentration in biological liquids decrease. Patents have cognitive and severe emotional impairment. Patients affected with thallium poisoning require long-term neurologist follow-up as well as rehabilitation

Impact of pathogen reduction methods on immunological properties of the COVID-19 convalescent plasma

Background and objectives: COVID-19 convalescent plasma is an experimental treatment against SARS-CoV-2. The aim of this study is to assess the impact of different pathogen reduction methods on the levels and virus neutralizing activity of the specific antibodies against SARS-CoV2 in convalescent plasma. Materials and methods: A total of 140 plasma doses collected by plasmapheresis from COVID-19 convalescent donors were subjected to pathogen reduction by three methods: methylene blue (M)/visible light, riboflavin (R)/UVB and amotosalen (A)/UVA. To conduct a paired comparison, individual plasma doses were divided into 2 samples that were subjected to one of these methods. The titres of SARS-CoV2 neutralizing antibodies (NtAbs) and levels of specific immunoglobulins to RBD, S- and N-proteins of SARS-CoV-2 were measured before and after pathogen reduction. Results: The methods reduced NtAbs titres differently: among units with the initial titre 80 or above, 81% of units remained unchanged and 19% decreased by one step after methylene blue; 60% were unchanged and 40% decreased by one step after amotosalen; after riboflavin 43% were unchanged and 50% (7%, respectively) had a one-step (two-step, respectively) decrease. Paired two-sample comparisons (M vs. A, M vs. R and A vs. R) revealed that the largest statistically significant decrease in quantity and activity of the specific antibodies resulted from the riboflavin treatment. Conclusion: Pathogen reduction with methylene blue or with amotosalen provides the greater likelihood of preserving the immunological properties of the COVID-19 convalescent plasma compared to riboflavin