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Food Chem ; 337: 127759, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32777568


High-resolution ultrasonic spectroscopy (HR-US) was applied for real-time monitoring of ß-casein hydrolysis by trypsin at various conditions for the first time. The technique is based on the precision measurement of hydration changes proportional to the number of peptide bond hydrolyzed. As HR-US exhibits ultrasonic transparency for most solution, the analysis did not require optical transparency like for 2,4,6-trinitrobenzenesulfonic acid (TNBS) assay. Appropriate enzymatic models were fitted with degree of hydrolysis (dh) profiles to provide kinetic and mechanistic description of proteolysis in terms of initial hydrolysis rate, r0, and rate constant of hydrolysis, kh, and enzyme inactivation, kd. Maximal r0 and dh were obtained at 45 °C and pH 8. The exponential dependence of kinetic parameters allowed determination of the activation (EA = 50.3 ± 7 kJ/mol) and deactivation (ED = 62.23 ± 3 kJ/mol) energies of hydrolysis. The ultrasonic assay provided rapid detection of trypsin activity even at sub-nanomolar concentration.

Sensors (Basel) ; 20(19)2020 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-33003538


This review is focused on the application of surface and volume-sensitive acoustic methods for the detection of milk proteases such as trypsin and plasmin. While trypsin is an important protein of human milk, plasmin is a protease that plays an important role in the quality of bovine, sheep and goat milks. The increased activity of plasmin can cause an extensive cleavage of ß-casein and, thus, affect the milk gelation and taste. The basic principles of surface-sensitive acoustic methods, as well as high-resolution ultrasonic spectroscopy (HR-US), are presented. The current state-of-the-art examples of the application of acoustic sensors for protease detection in real time are discussed. The application of the HR-US method for studying the kinetics of the enzyme reaction is demonstrated. The sensitivity of the acoustics biosensors and HR-US methods for protease detection are compared.

J Neurosci Nurs ; 50(5): 308-312, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30138153


Venous thromboembolism (VTE) is a frequent and potentially fatal complication of immobility caused by cerebrovascular disease. This review examines the efficiency of deep vein thrombosis (DVT) prophylaxis methods. Patients with stroke initiated on DVT prophylaxis were compared with those who did not have any prophylaxis. Integrative review research design was used and included articles from 2010 to 2016. Search terms such as "DVT prophylaxis" and "stroke" were used to identify scientific publications. Of 173 studies identified, 12 articles were included and rated using the Canadian Medical Association and Center for Evidence-Based Medicine Level of Evidence ranking system. Of DVT prophylaxis methods identified, intermittent pneumatic compression device was superior to antiembolic stockings. Current data showed that the stockings were insufficient in preventing VTE. Heparin and low-molecular-weight heparin were efficient chemoprophylaxis in reducing the incidence of VTE. The combination of chemical and mechanical DVT prevention is recommended.

Anticoagulantes/uso terapêutico , Heparina de Baixo Peso Molecular/uso terapêutico , Acidente Vascular Cerebral/complicações , Trombose Venosa/tratamento farmacológico , Medicina Baseada em Evidências , Humanos , Dispositivos de Compressão Pneumática Intermitente , Fatores de Risco