Perioperative administration of vedaprofen, tramadol or their combination does not interfere with platelet aggregation, bleeding time and biochemical variables in cats

A randomized double blind and placebo controlled design was used to investigate the hemostatic, biochemical, gastrointestinal and behavioral effects of pre- and postoperative administration of vedaprofen 0.5 mg/kg PO (V), tramadol 2 mg/kg SC (T), their association (VT) or placebo (P) in 40 adult female cats (3.0 +/- 0.32 kg; 1.8 +/- 0.7 years) distributed in groups of 10. Platelet aggregation and bleeding time were measured before and 52 11 after ovariohysterectomy. Serum urea, creatinine, alanine aminotransferase, alkaline phosphatase and gamma-glutamyl transferase concentrations were measured before and 7 days postoperatively. The occurrence of vomiting, frequency and consistency of feces, and behavior were observed for 7 days postoperatively. Morphine (0.5 mg/kg, IM) was used as rescue analgesic. Laboratory variables did not change. Vomiting was observed only after morphine administration. Mild euphoria was observed in T and VT. The perioperative use of vedaprofen and/or tramadol did not modify the hemostatic, biochemical and gastrointestinal function in cats. (C) 2009 ESFM and AAFP. published by Elsevier Ltd. All rights reserved.

The variance of the index (R) of aggregation of Clark and Evans

The exact formula for the variance of the Index (R) of aggregation of Clark and Evans is derived. Due to the fact that R is a dimensionless number, its variance is independent of population density, being only a function of the sample size and so can be manipulated. © 1985 Springer-Verlag.

Effect of electrolyte on the gelation and aggregation of SnO2 colloidal suspensions

Electrolytes may modify the physical-chemical characteristics of colloidal particle interfaces in suspension, which can favour gel or aggregate formation. The influence of NH4Cl loading on the aggregation and gelation of SnO2 colloidal suspensions was investigated using measurements of rheology, turbidity and infrared spectra. A rapid aggregate growth for samples with Cl- > 20 mM was observed. With increasing age, gelation was observed due to formation of interaggregate bonds. For concentration of Cl- between 20 and 9 mM, the aggregation process was slower allowing the formation of gel with a network which was not destroyed as the gel was submitted to a small rate of shear. As aging continues, the condensation reaction between OH groups gave rise to the formation of Sn-O bonds, irrespective of the electrolyte loading. © 1992 Elsevier Science Publishers B.V. All rights reserved.

Larval dispersal in Chrysomya megacephala, Chrysomya putoria and Cochliomyia macellaria (Dipt., Calliphoridae): Ecological implications of aggregation behaviour

In this study we investigate aggregated patterns as a consequence of post-feeding larval dispersal in three blowfly species, based on the frequency distribution of sampling units in the substrate having 0, 1, 2,..., n pupae. Statistical analysis revealed that aggregated patterns of distribution emerge as a consequence of larval dispersal, and Cochliomyia macellaria has higher levels of aggregation when compared to Chrysomya megacephala and C. putoria. Aggregation during dispersal is associated with a spatial pattern where most larvae in the species tend to pupariate near the food source. The possible consequences for the population ecology of these species are discussed.

Ultrastructure of the gland responsible for the synthesis of an aggregation pheromone in Rhynchophorus palmarum (L.) (Coleoptera: Curculionidae)

The ultrastructure of the glands responsible for synthesizing the aggregation pheromone rhynchophorol in the beetle Rhynchophorus palmarum (L.) was studied. Glands from live beetles were removed and examined under a light microscope using semithin sections (∼1μm) and under a transmission electron microscope (TEM) using ultrathin sections (60 nm). The glands show an alveolar structure without a reservoir and the cells making up the gland are arranged in a typical acinus pattern. The existence of two types of cells with different electron densities, secretion canaliculi, numerous mitochondria and smooth endoplasmic reticulum in abundance were observed. These latter organelles are characteristic of cells which synthetize non-proteinaceous substances and are thus, likely candidates for the producion of rhynchophorol.

Larval aggregation and competition for food in experimental populations of Chrysomya putoria (Wied.) and Cochliomyia macellaria (F.) (Dipt., Calliphoridae)

In blowflies, larval aggregation in patches of food can be both intra- and interspecific, depending upon the degree to which competitors are clumped among the patches. In the present study, the implications of spatial aggregation for larval competition was investigated in experimental populations of the introduced blowfly Chrysomya putoria and the native Cochliomyia macellaria, using data from survival to adulthood in a range of single- and double-species larval cultures. The reduction in C. macellaria survival rate in the presence of C. putoria suggests that the former species is the inferior competitor. The results on survival to adulthood for both species in single- and double-species cultures can be explained in the light of the relationship between the level of intra- and interspecific aggregation and the efficiency of the larval feeding process. The possible implications of these results for the population biology of both species in natural environments are discussed.

The thrombocyte aggregation process in the turtle Phrynopys hilarii (Chelonia). An ultrastructural study

This study investigates the thrombocyte aggregation process in the South American fresh water turtle (Phrynopys hilarii) using electron microscopy. Blood was taken from surgically exposed lateral neck vessels often turtles Phrynopys hilarii during the spring and summer seasons, when the mean temperature is 37°C. Blood samples were fixed with Karnovsky solution for processing by transmission electron microscopy. The turtle thrombocytes were spindle-shaped with lobulated nuclei. Prominent vesicles and canaliculi were found throughout the cytoplasm. The cytoplasm organelles showed an agranular endoplasmatic reticulum, Golgi complex near the centrioles and scattered free ribosomes. These cells are similar to bird thrombocytes but distinct from fish and frog thrombocytes. Blood clotting time was 5 min ± 30 sec measured by the Lee and White method. Structural alterations resulting from the aggregation process occurred after activation. Thrombocytes developed numerous filopodial projections, an increased number of vacuoles and changed from spindle to spherical shape. P. hilarii thrombocytes have different morphologic characteristics compared to other non-mammalian vertebrate cells. These cells can participate in the aggregation process, as observed in birds.

Aspectos estruturais da membrana eritrocitária

This article describes the structures and functions of the erythrocyte membrane and its importance in transfusional medicine. The erythrocyte membrane is one of the best known membranes in terms of structure, function and genetic disorders. As any other plasma membrane, it mediates transport functions. It also provides the erythrocytes with their resilience and deformability. According to the International Society of Blood Transfusion (ISBT), more than 500 antigens are expressed in the erythrocyte membrane, and around 270 are involved in transfusion reaction cases and hemolytic diseases of the fetus and newborn. In the ISBT classification, the high frequency series is represented by antigens in more than 99% of population (high prevalence antigen). In transfusion, the absence of these antigens determines severe problems as for example, one woman without the P antigen suffered 6 repetitive miscarriages due to placental insufficiency, which was caused by an antibody formed against the absent P antigen. Some important erythrocyte membrane proteins are described here including Band 3, Glycophorins and spectrin. The most abundant integral membrane protein is Band 3 and its main function is to mediate exchange of chloride and bicarbonate anions across the plasma membrane. The second most abundant integral membrane protein in the human erythrocyte is sialoglycoprotein glycophorin A (GPA). With its high sialic acid content, GPA is the main contributor to the net negative cell-surface charge and is thus critical for minimizing cell-cell interactions and preventing red cell aggregation. Glycophorin C (GPC) is the receptor for PfEBP-2 (baebl, EBA-140), the newly identified erythrocyte binding ligand of Plasmodium falciparum. The ternary complex of spectrin, actin and 4.1R defines the nodes of the erythrocyte membrane skeletal network, and is inseparable from membrane stability when under mechanical stress. This erythrocyte membrane review is important for a better understanding of transfusion reactions, where the antibody formation against high prevalence antigens makes compatible transfusions difficult. The study of antigen diversity and biochemical characterization of different proteins will contribute to healthcare, as well as diagnosis, development of technology such as monoclonal antibody production and the therapeutic conduct of many diseases.

Thermal denaturation and aggregation of hemoglobin of Glossoscolex paulistus in acid and neutral media

The thermal denaturation and aggregation of the HbGp, in the oxy- and cyanomet-forms, was investigated by DSC, AUC, DLS, optical absorption and CD, in the pH range from 5.0 to 7.0. Oxy-HbGp has a denaturation process partially reversible and dependent on the temperature. DSC melting curve is characterized by a single peak with Tc value of 333.4±0.2K for oxy-HbGp, while two peaks with Tc values of 332.2±0.1 and 338.4±0.2K are observed for cyanomet-HbGp, at pH 7.0. In acidic pH oxy- and cyanomet-HbGp are more stable showing higher Tc values and aggregation. AUC data show that, HbGp, at pH 7.0, upon denaturation, remains undissociated at 323K, presenting oligomeric dissociation at 333 (12±3% of tetramer and 88±5% of whole HbGp) and 343K (70±5% of monomer and 30±2% of trimer). DLS data show that the lag period before aggregation is dependent on the temperature and HbGp concentration. Optical absorption and CD results show that the increase of temperature leads to the oxy-HbGp oxidation and aggregation, above 331K, in acidic pH. CD data, for HbGp, present a greater thermal stability in acid medium than at neutral pH, with similar Tc values for both oxidation forms. Our data are consistent with previous studies and represents an advance in understanding the thermal stability of oligomeric HbGp structure. © 2012 Elsevier B.V.

Dimerization of aurein 1.2: Effects in structure, antimicrobial activity and aggregation of Cândida albicans cells

Antimicrobial peptides (AMPs) are a promising solution to face the antibiotic-resistant problem because they display little or no resistance effects. Dimeric analogues of select AMPs have shown pharmacotechnical advantages, making these molecules promising candidates for the development of novel antibiotic agents. Here, we evaluate the effects of dimerization on the structure and biological activity of the AMP aurein 1.2 (AU). AU and the C- and N-terminal dimers, (AU)2K and E(AU)2, respectively, were synthesized by solid-phase peptide synthesis. Circular dichroism spectra indicated that E(AU)2 has a coiled coil structure in water while (AU)2K has an α-helix structure. In contrast, AU displayed typical spectra for disordered structures. In LPC micelles, all peptides acquired a high amount of α-helix structure. Hemolytic and vesicle permeabilization assays showed that AU has a concentration dependence activity, while this effect was less pronounced for dimeric versions, suggesting that dimerization may change the mechanism of action of AU. Notably, the antimicrobial activity against bacteria and yeast decreased with dimerization. However, dimeric peptides promoted the aggregation of C. albicans. The ability to aggregate yeast cells makes dimeric versions of AU attractive candidates to inhibit the adhesion of C. albicans to biological targets and medical devices, preventing disease caused by this fungus. © 2013 Springer-Verlag Wien.

Influence of risk behavior aggregation in different categories of physical activity on the occurrence of cardiovascular risk factors

Background: We aimed to verify the association of risk behavior aggregation in different categories of physical activity (PA) with the presence of cardiovascular risk factors (RF) employees at a public university. Method. We analyzed data of 376 employees, which were visited in their workplace for measurement of weight, height and questionnaires to identify the risk behaviors and risk factors. Chi-square test was used to analyze the association between the dependent and independent variables and binary logistic regression was used to construct a multivariate model for the observed associations. Results: Associations were found between the aggregation of following risk behaviors: smoking, alcohol consumption and physical inactivity, considered in different categories of PA, and the increase in RF, except for the presence of hypertriglyceridemia. Individuals with two or more risk behaviors in occupational PA category are more likely to be hypertensive (3.04 times) and diabetes (3.44 times). For the free time PA category, these individuals were 3.18 times more likely to have hypercholesterolemia and for locomotion PA, more likely to be hypertensive (2.42 times) and obese (2.51 times). Conclusion: There are association between the aggregation of two or more risk behaviors and the presence of cardiovascular RF. © 2013 Bernardo et al.; licensee BioMed Central Ltd.