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This paper presents a preliminary study of the effects of the anesthetics propofol, remifentanil, and vecuronium bromide on the rheological properties of glycated erythrocytes in vitro, modeling the glycation by hyperglycemia observed in diabetes. Viscoelastic and aggregation kinetic parameters of erythrocytes were determined using an erythrocyte rheometer and an optical chip aggregometer developed in our laboratory. The results showed significant alterations in the membrane surface viscosity, the elastic modulus, and the erythrocyte deformability index for the different anesthetics studied. Also, the kinetics aggregation parameters showed different types of alterations due to the effect of anesthetics. This preliminary study suggests that the use of these anesthetics in diabetic patients could induce hemorheological alterations that disturb the microcirculation. For this reason, it is recommended to deepen these investigations to prevent complications in surgical procedures.

En este estudio se analizaron los parametros viscoelasticos y de agregacion en globulos rojos humanos sometidos a los procedimientos habituales de irradiacion gamma con fines transfusionales. Las muestras fueron irradiadas a diferentes dosis a fin de determinar los posibles cambios hemorreologicos que pudieran afectar a la salud de los pacientes y su relacion con las modificaciones bioquimicas observadas. Los resultados obtenidos muestran alteraciones en el tiempo de agregacion, en la viscosidad superficial de membrana y en el tamano de los agregados eritrocitarios en las muestras irradiadas, sugiriendo que el dano producido por la radiacion ionizante afecta a las propiedades fisicas de la membrana del globulo rojo en diferentes niveles.

Several studies report flow disturbance and microcirculation disorders upon anesthesia treatment. These alterations are often related to blood rheology changes. In this work, it was attempted to make a detailed description of the alterations in erythrocyte mechanical properties by the action of propofol, remifentanil, and vecuronium. For this, an in vitro study was performed on red blood cell samples from healthy donors incubated with solutions of propofol (4 μg/ml whole blood), remifentanil (10 ng/ml plasma), and vecuronium (0.15 μg/ml plasma). Erythrocyte viscoelastic parameters were determined by octuplicate using a Reometro Eritrocitario. Also, a Wilcoxon signed rank-test with Yates correction for continuity was performed to analyze the overall alteration in the mechanical properties of erythrocytes. Statistical analysis showed that the three studied anesthetics changed the erythrocyte mechanical properties at different parts of the membrane. These results would imply an interaction of these anesthetics with the erythrocyte membrane. Finally, this could conduce to alterations in microcirculation.

Background: T. spiralis establishes an intimate contact with the host erythrocytes during the newborn larvae migration through the bloodstream to their encystment in the muscle. Objective: In the present work we study the alterations in the mechanical and aggregation properties of red blood cells produced in Vitro by newborn larvae at low concentrations (100, 250, 500, and 1000 larvae/mL). Methods: The study was performed by incubating human erythrocytes with an equal volume of different concentrations of newborn larvae for 30 minutes, with controlled agitation. To evaluate the erythrocyte alterations by the action of the larvae, the Erythrocyte Rheometer, the Optical Chip Aggregometer, and the Digital Image Analysis were used. Results: In the treated erythrocyte samples, a decrease in isolated cell numbers and an increase in the aggregates were observed respect to the control at the higher larval concentration (1000 larvae/mL). The deformability index, the elastic modulus and surface viscosity showed no significant differences with the control; however, the storage modulus of the erythrocyte membrane decreased significantly with the increase in larval concentration. Erythrocyte aggregation parameters showed that the aggregation index increased with the larvae concentration present in the incubation, highlighting the presence of larger aggregates and clusters. The time to attain half of the maximum aggregation diminished, which implies faster aggregation kinetics. Conclusion: The results observed in Vitro describe the red blood cell alterations that could be produced during in vivo infection in the host. Fil: Ponce de León, Patricia Carolina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina Fil: Toderi Cicchini, Martín Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina Fil: Castellini, Horacio Virginio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Riquelme, Bibiana Doris. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina

During diabetes, the characteristic hyperglycemia can induce red blood cell glycation. Several researchers have proposed different protocols to perform an in vitro model to study this phenomenon. In this article, some of the most important in vitro glycation protocols available in the bibliography were compared to each other. The incubation parameters as the suspension medium, glucose concentration, red blood cell concentration, time, and temperature were analyzed. Also, several assays were carried out in our laboratory, and glycated hemoglobin, erythrocyte aggregation and viscoelasticity were determined for the protocol validation. Based on the bibliographic analysis and our experimental results, an optimal protocol for in vitro glycation of red blood cells is presented.

Fil: Riquelme, Bibiana Doris. Universidad Nacional de Rosario. Facultad de Ciencias Bioquimicas y Farmaceuticas. Instituto de Fisica Rosario (IFIR-CONICET); Argentina.

The complex life cycle of Trichinella spiralis includes the migration of newborn larvae through the bloodstream to their encystment in muscle. The parasite establishes an intimate contact with the erythrocytes of the host both during the migration of the newborn larvae and when encysting, as this parasite causes intense vascularization in the muscle cell. The goal of this work was to study the effects of various concentrations of T. spiralis muscle larvae (ML) on erythrocyte membranes. The treatment was performed by incubating human erythrocytes with equal volume of different concentrations of ML for 30 minutes, with controlled agitation (37°C). The control erythrocytes (with no contact with the larvae) were incubated in the same way with an equal volume of physiological solution. To evaluate the alterations to the erythrocytes by the action of the larvae and in the respective controls, an Erythrocyte Rheometer and a Digital Image Analysis technique were used. The results indicated that when the larval concentration was higher, the aggregation and erythrocyte membrane alterations were also higher. Also, the erythrocyte deformability index and the erythrocyte elasticity increased. The values of isolated cell coefficient varied from 0.51 in the treatment with 100 larvae/ml to 0.91 in the incubation with 1000 larvae/ml. This experiment shows that T. spiralis muscle larvae affect significantly the red blood cell aggregation and the erythrocyte viscoelastic properties.

Linear and non-linear viscoelasticity of red blood cells was characterized using a new Optical Erythrocyte Rheometer based on laser diffractometry technique. Optical and mechanical models were developed to obtain representative parameters for clinical application.

The study of red blood cell (RBC) aggregation is of great interest because of its implications for human health. Altered RBC aggregation can lead to microcirculatory problems as in vascular pathologies, such as hypertension and diabetes, due to a decrease in the erythrocyte surface electric charge and an increase in the ligands present in plasma. The process of erythrocyte aggregation was studied in stasis situation (free shear stresses), using an optical chip based on the laser transmission technique. Kinetic curves of erythrocyte aggregation under different conditions were obtained, allowing evaluation and characterization of this process. Two main characteristics of blood that influence erythrocyte aggregation were analyzed: the erythrocyte surface anionic charge (EAC) after digestion with the enzyme trypsin and plasmatic protein concentration in suspension medium using plasma dissolutions in physiological saline with human albumin. A theoretical approach was evaluated to obtain aggregation and disaggregation ratios by syllectograms data fitting. Sensible parameters ( Amp 100 , t 1 \ 2 ) regarding a reduced erythrocyte EAC were determined, and other parameters (AI, M-Index) resulted that are representative of a variation in the plasmatic protein content of the suspension medium. These results are very useful for further applications in biomedicine. Fil: Toderi Cicchini, Martín Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Castellini, Horacio Virginio. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina Fil: Riquelme, Bibiana Doris. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina

Acid gelation of proteins is commonly used in the food industry and it can be induced by the addition of glucono-delta-lactone (GDL). The aim of this work was to use textural analysis of images in order to assess possible changes in the microstructure of bovine sodium caseinate (NaCAS) and soy protein isolate (SPI) acid gels. The gelation rate of NaCAS related to the amount of GDL was evaluated. Also, the effect of the presence of NaCAS hydrolyzates obtained at different hydrolysis times by the enzyme of Bacillus sp. P7 was studied. Finally, SPI acid gels were evaluated in the presence of whey soy protein isolate (WSP) in different ratios. The gel images were obtained by conventional optical microscopy and texture parameters were obtained by using specific programs which were developed in Python language. Shannon entropy, smoothness, mean normalized grey level variance and uniformity were analyzed as estimators of the texture of the images obtained. Results obtained in the evaluated systems showed that these parameters were able to represent the structural changes in the gel network, as changes in size of pores or in degree of compactness. Also, these results were contrasted with rheological properties of the systems evaluated.

Drugs used during anesthesia might induce disturbance on microcirculation due to their systemic cardiovascular actions and to direct hemorheological effects. A comparative investigation of the hemorheological alterations related to in vitro propofol treatment of red blood cells (RBCs) from healthy and diabetic volunteers is presented here. Viscoelasticity and aggregation of RBCs from type 2 diabetic patients (DBT) and healthy donors (HD) were studied from RBCs incubated with propofol near steady-state concentration. 'S parameter', which measures the aggregation degree, was obtained using digital analysis of microscopic images. Erythrocyte viscoelasticity parameters were determined using an Erythrocyte Rheometer. Results obtained from DBT samples showed an increase of 10% or more in aggregation due to the propofol action. The phase shift between erythrocyte response and oscillating shear stress applied at 1 Hz was altered by propofol treatment of erythrocyte from HD and DBT. Propofol could produce slight alterations in the rheological behavior of erythrocyte from HD and DBT, at concentrations near those of steady state. Moreover, this anesthetic could induce an adverse effect in DBT, particularly on erythrocyte aggregation. The observed hemorheologic alteration would increase the possibility of microcapillary obstruction. Hence, this type of study [0] would prove relevant to avoid possible postoperative complications.

Traditional techniques to evaluate the aggregation of red blood cells by optical methods require large sample volume and provide parameters that vary significantly from one method to another. A simplified variant of a chip system previously developed by Shin et al. (2009) 1 based on light transmission for measuring erythrocyte aggregation is presented. Through a detailed analysis of intensity versus time curves, relevant information about erythrocyte aggregation and its variables is obtained. Parameters that provide more accuracy for the diagnosis of patients in order to have an immediate application in Clinical Medicine are proposed.

Drugs used during anesthesia could enhance microvascular flow disturbance, not only for their systemic cardiovascular actions but also by a direct effect on the microcirculation and in particular on hemorheology. This is particularly important in high-risk surgical patients such as those with vascular disease (diabetes, hypertension, etc.). Therefore, in this work we propose a set of innovative parameters obtained by digital analysis of microscopic images to study the in vitro hemorheological effect of propofol and vecuronium on red blood cell from type 2 diabetic patients compared to healthy donors. Obtained innovative parameters allow quantifying alterations in erythrocyte aggregation, which can increase the in vivo risk of microcapillary obstruction.