Chronobiological approach to study microsymbiont catalase activity in female reproductive tract

Catalase is a heme-containing enzyme belonging to protection factors that destroys peroxide compounds. The presence of catalase activity is an important ability of microorganisms that allows them to be protected from unfavorable factors as well as adapt to macroorganism conditions. Catalase along with superoxide dismutase plays an important role in pathogen resistance to phagocyte oxygen-dependent bactericidal mechanisms. The aim of the study was to investigate microsymbiont catalase activity from female reproductive tract in normocenosis and candidiasis dysbiosis using the chronobiological approach. The study was conducted on clinical isolates, isolated from female reproductive tract microsymbiocenosis. The catalase activity was determined by spectrophotometry based on 24 hour-long hydrogen peroxide reduction with 3-hours interval in winter season. Dynamic hydrogen peroxide was assessed in 3–5 experiment replicates. In some Lactobacillus spp., catalase was found containing no heme group — pseudocatalase. Chronobiological approach allowed to reveal enzyme activity from all microsymbionts. The dominant and associative microbiota isolated from healthy females was characterized by circadian (24 hours) rhythms of catalase activity early in the morning — 5 a.m. (р 0.05). Hydrogen peroxide decomposes spontaneously or via non-enzymatic catalysts, and microorganisms cope with this situation under such conditions. In microsymbionts characteristic of female reproductive tract dysbiosis, and usually found in large numbers along with decreased Lactobacillus spp. ultradian rhythms with 12- and 8-hour harmonics of catalase activity with acrophase were recorded in the morning (8 a.m.) and evening hours (8 p.m.). The minimum values of enzyme production in all cultures were recorded at 12 p.m. and 5 p.m. Therefore, the contribution of the rhythm of the studied parameter at varying degree of vaginal sterility reflects the adaptive pathogen capabilities to the conditions of existence and can be the basis for studying related regulatory mechanisms. Mesor and amplitude phase stability are universal rhythmometric parameters used to evaluate patient’s condition independent of species assignment

Intensive Care Unit Admission Parameters Improve the Accuracy of Operative Mortality Predictive Models in Cardiac Surgery

BACKGROUND: Operative mortality risk in cardiac surgery is usually assessed using preoperative risk models. However, intraoperative factors may change the risk profile of the patients, and parameters at the admission in the intensive care unit may be relevant in determining the operative mortality. This study investigates the association between a number of parameters at the admission in the intensive care unit and the operative mortality, and verifies the hypothesis that including these parameters into the preoperative risk models may increase the accuracy of prediction of the operative mortality. METHODOLOGY: 929 adult patients who underwent cardiac surgery were admitted to the study. The preoperative risk profile was assessed using the logistic EuroSCORE and the ACEF score. A number of parameters recorded at the admission in the intensive care unit were explored for univariate and multivariable association with the operative mortality. PRINCIPAL FINDINGS: A heart rate higher than 120 beats per minute and a blood lactate value higher than 4 mmol/L at the admission in the intensive care unit were independent predictors of operative mortality, with odds ratio of 6.7 and 13.4 respectively. Including these parameters into the logistic EuroSCORE and the ACEF score increased their accuracy (area under the curve 0.85 to 0.88 for the logistic EuroSCORE and 0.81 to 0.86 for the ACEF score). CONCLUSIONS: A double-stage assessment of operative mortality risk provides a higher accuracy of the prediction. Elevated blood lactates and tachycardia reflect a condition of inadequate cardiac output. Their inclusion in the assessment of the severity of the clinical conditions after cardiac surgery may offer a useful tool to introduce more sophisticated hemodynamic monitoring techniques. Comparison between the predicted operative mortality risk before and after the operation may offer an assessment of the operative performance

The interaction between preoperative platelet count and function and its relationship with postoperative bleeding in cardiac surgery

Platelet function tests (PFTs) before cardiac surgery are predictive of postoperative bleeding and can guide a correct timing of surgery in patients under P2Y12 inhibitors. Thrombocytopenia affects PFT and may determine postoperative bleeding. The present study aims to investigate the relationship between platelet count and function, and its role in determining postoperative bleeding in cardiac surgery patients pre-treated with P2Y12 inhibitors. The study includes 589 consecutive cardiac surgery patients, tested before surgery with platelet count and multiple electrode aggregometry (MEA) ADPtest (investigating P2Y12 receptor platelet reactivity) and TRAPtest (investigating the thrombin-dependent platelet reactivity). Platelet function was linearly associated (P = 0.001) with platelet count at the ADPtest and the TRAPtest, demonstrating a positive association in the whole spectrum of platelet count. The ADPtest (P = 0.001) and platelet count (P = 0.001) were negatively associated with postoperative bleeding, whereas the TRAPtest was not. At a multivariable analysis, the ADPtest (P = 0.026) and platelet count (P = 0.006) remained independent predictors of postoperative bleeding. The platelet transfusion rate was 5.7% in patients with ADPtest ≥30 U and platelet count ≥150 000 cells/µL, 14.3% in patients with ADPtest ≥30 U and platelet count <150 000 cells/µL, 38.9% in patients with ADPtest <30 U and platelet count ≥150 000 cells/µL, and 50% in patients with ADPtest <30 U and platelet count <150 000 cells/µL (P = 0.001). Platelet function at MEA is dependent on the platelet count not only in the case of thrombocytopenia, but also in the whole range of platelet count; preoperative platelet count and function are determinants of postoperative bleeding, with a larger effect on platelet transfusions attributable to a poor P2Y12-dependent platelet function

Platelet Contribution to Clot Strength in Thromboelastometry: Count, Function, or Both?

In thromboelastometry (ROTEMTM) the difference in amplitude between the EXTEM and the FIBTEM is considered an index of platelet contribution to clot strength (PCSamp). The difference in elasticity (PCSel) is rarely used. We investigated the ability of PCSamp and PCSel in reflecting platelet count and function in 103 patients undergoing cardiac surgery, simultaneously measuring ROTEM and platelet function tests (multiple electrode aggregometry ADPtest and TRAPtest, MultiplateTM). PCSamp and PCSel were tested for association with platelet count and function. The PCSamp showed a low (R coefficient 0.32–0.39) association with platelet count and function (ADPtest), whereas the PCSel showed higher values of association (R coefficient 0.55–0.71) with the same variables. No association was found between PCS and TRAPtest. In a multivariable model, both the platelet count (R coefficient 0.60, P = 0.001) and the ADPtest (R coefficient 0.36, P = 0.001) were independently associated with the PCSel. The discrimination properties of the PCSel for the prediction of a low platelet count/function were very good (c-statistics 0.837). In clinical practice, the difference in elasticity between EXTEM and FIBTEM should replace the difference in amplitude