Importance of the lipid peroxidation biomarkers and methodological aspects FOR malondialdehyde quantification

Free radicals induce lipid peroxidation, playing an important role in pathological processes. The injury mediated by free radicals can be measured by conjugated dienes, malondialdehyde, 4-hydroxynonenal, and others. However, malondialdehyde has been pointed out as the main product to evaluate lipid peroxidation. Most assays determine malondialdehyde by its reaction with thiobarbituric acid, which can be measured by indirect (spectrometry) and direct methodologies (chromatography). Though there is some controversy among the methodologies, the selective HPLC-based assays provide a more reliable lipid peroxidation measure. This review describes significant aspects about MDA determination, its importance in pathologies and biological samples treatment.

LC-MS/MS method applied to preclinical pharmacokinetic investigation of olanzapine-loaded lipid-core nanocapsules

In spite of different methods reported in the literature to determine olanzapine in biological fluids, all of them used high volumes of plasma. Therefore, the purpose of this paper was to develop an LC-MS/MS method using small plasma volume (0.1 mL) to apply in a preclinical pharmacokinetic investigation. The method was linear over the concentration ranges of 10 - 1000 ng mL-1. Extraction recoveries, stability, and validation parameters were evaluated. Results were within the acceptable limits of international guidelines. A significant decrease in clearance led to a significant 2.26-times increase in AUC0 - 6h of olanzapine-loaded lipid-core nanocapsules compared with free-olanzapine.

CHARACTERIZING THE MECHANISM OF QUETIAPINE DISTRIBUTION IN LIPID-CORE NANOCAPSULES PSEUDO-PHASES USING A VALIDATED LC/UV METHOD

Quetiapine is an atypical antipsychotic used to treat schizophrenia. However, despite great interest for its chronic therapeutic use, quetiapine has some important side effects such as weight gain induction. The development of a quetiapine nanocarrier can potentially target the drug into central nervous system, resulting in a reduction of systemic side effects and improved patient treatment. In the present work, a simple liquid chromatography/ultraviolet detection (LC/UV) analytical method was developed and validated for quantification of total quetiapine content in lipid core nanocapsules as well as for determination of incorporation efficiency. An algorithm proposed by Oliveira et al. (2012) was applied to characterize the distribution of quetiapine in the pseudo-phases of the nanocarrier, leading to a better understanding of the quetiapine nanoparticles produced. The analytical methodology developed was specific, linear in the range of 0.5 to 100 µg mL−1 (r2 > 0,99), and accurate and precise (R.S.D < ±5%). The absolute recovery of quetiapine from the nanoparticles was approximately 98% with an incorporation efficiency of approximately 96%. The results indicated that quetiapine was present in a type III distribution according to the algorithm, and was mainly located in the core of the nanoparticle because of its logD in the formulation pH (6.86 ± 0.4).

Effect of adjuvants on the amount of air included in droplets generated by spray nozzles

The air included in droplets generated by spray nozzles directly int0erferes in transport, deposition and retention of the droplets after its impact on the target. The objective of this study was to analyze the interference of adjuvants in the amount of air included in droplets generated by spray nozzles. The treatments were composed by four spray solutions containing mineral oil, vegetable oil, surfactant and water, and three spray nozzles, two air induction type and one pre-orifice. The air included was calculated by the difference between the volume of spray mix (air plus liquid) and only the liquid, which was made by means of sprayed samples captured in a funnel and collected in a graduated cylinder. The surface tension was estimated by the gravimetric method using a precision scale and a graduated pipette. The surfactant provided the largest percentage of air included in the spray. For the surface tension, the mineral oil and the surfactant had the lowest values. It was concluded that the use of adjuvants had a direct influence on the percentage of air included. In addition, products with greater ability to reduce surface tension and to form homogeneous solutions provided the increase in the percentage of air included in the droplet.

Physical characteristics of oily spraying liquids and droplets formed on coffee leaves and glass surfaces

The physical characteristics of a spray liquid are important in getting a good droplet formation and control efficiency over a particular target. As a function of these characteristics, it is possible to decipher which is the best adjuvant based on the respective concentration used during the spray. Therefore, ten spraying liquids were prepared, which varied in concentrations of pesticide lufenuron + profenofos, mineral oil, water and manganese sulfate. Pendant droplets formed from these mixtures were measured to examine their impact on surface tension. Droplets were applied to the surface of coffee leaves and the surface tension, contact angle formed and the leaf area wetted by the droplet, were measured. A smooth glass surface was taken as a comparative to the coffee leaves. The highest concentrations of oil resulted in lower surface tension, smaller contact angles of droplets on leaf surfaces and larger areas wetted by the droplets. Both surfaces showed hydrophilic behavior.

Spraying systems and traveling speed in the deposit and spectrum of droplets in cotton plant

ABSTRACT Tractor traveling speed can influence the quality of spraying depending on the application technology used. This study aimed to evaluate the droplet spectrum, the deposition and uniformity of spray distribution with different spraying systems and traveling speeds of a self-propelled sprayer in two phenological stages of the cotton plant (B9 and F13). The experimental design was randomized blocks and treatments were three spraying techniques: common flat spray tips; tilted flat jet with air induction, at 120 L ha-1; and rotary atomizer disk, 20 L ha-1, combined with four traveling speeds: 12, 15, 18 and 25 km h-1, with four replications. Spraying deposition was evaluated for both leaf surfaces from the cotton plant apex and base (stage B9) and middle part of the plant (stage F13) with a cupric marker. A laser particle analyzer also assessed the droplet spectrum. The centrifugal power spray system produces more homogeneous droplet spectrum and increased penetration of droplets into the canopy in both phenological stages. Variation on the operating conditions necessary for increased traveling speed negatively influences the pattern of spraying deposits.

Effects of splenic allograft in lipid profile of non-splenectomized rats: the immune and metabolic role of the "double spleen"

OBJECTIVE: To elucidate the role of the spleen and splenic allograft in lipid control and evaluate its effect on the lipid profile of rats.METHOD: 32 male Wistar rats were randomly assigned into four groups: control group (1), total splenectomy group (2), splenectomy and implantation of allograft group (3) and double spleen group (4). Each group was subdivided into two subgroups: A and B, based on the death of the animals after 30 or 120 days of monitoring. The procedures in groups 2, 3 and 4 were made simultaneously, and splenectomized animals, groups 2 and 3 were donors, respectively, for the animals of groups 3 and 4. In group 4 the spleen was preserved and the animals received implants from the spleens of rats from group 3. The regeneration of splenic tissue was evaluated by macroscopic and microscopic analyzes of the grafts and own spleens, as well as with measurements of VLDL, HDL, LDL, total cholesterol and triglycerides.RESULTS: after 120 days, Group 4 showed levels of total cholesterol and LDL lower than the other groups. Group 1 had higher levels of lipids.CONCLUSION: The technique of double spleen was effective in the control of lipid metabolism, corroborating the function of the spleen as a reserve of lipids.

Impact of Roux-en-Y gastric bypass on lipid and inflammatory profiles

Objective: To evaluate the behavior of acute phase proteins and lipid profile in patients undergoing Roux-en-Y gastric bypass. Methods : We conducted a prospective study, consisting of three moments: M1 - preoperative (24 hours before surgery); M2 - 30 days after surgery; and M3 - 180 days after surgery. We carried measured height and BMI, as well as determined the concentrations of acute phase proteins (C-reactive protein (CRP), albumin and Alpha-1-acid glycoprotein) and total cholesterol, LDL-c, HDL-c and triacylglycerol. Results : participants comprised 25 individuals, with a mean age of 39.28 ± 8.07, 72% female. At all times of the study there was statistically significant difference as for weight loss and BMI. We found a significant decrease in CRP concentrations between the moments M1 and M3 (p = 0.041) and between M2 and M3 (p = 0.018). There was decrease in Alpha-1-GA concentrations between M1 and M2 (p = 0.023) and between M1 and M3 (p = 0.028). The albumin values increased, but did not differ between times. Total cholesterol and triacylglycerol decreased significantly ay all times. LDL-c concentrations decreased and differed between M1 and M2 (p = 0.001) and between M1 and M3 (p = 0.001). HDL-c values increased, however only differing between M1 and M2 (p = 0.050). Conclusion : Roux-en-Y gastric bypass promoted a decrease in plasma concentrations of CRP and Alpha-1-acid glycoprotein, improving lipid and inflammatory profiles.

Association between Lipid Accumulation Product and Hirsutism in Patients with Polycystic Ovary Syndrome

Objective Polycystic ovary syndrome (PCOS) is the most common endocrine metabolic disorder in women between menarche and menopause. Clinical hyperandrogenism is the most important diagnostic criterion of the syndrome, which manifests as hirsutism in 70% of cases. Hirsute carriers of PCOS have high cardiovascular risk. Lipid accumulation product (LAP) is an index for the evaluation of lipid accumulation in adults and the prediction of cardiovascular risk. The aim of this study was to evaluate the association between LAP and hirsutism in women with PCOS. Methods This was a cross-sectional observational study of a secondary database, which included 263 patients who had visited the Hyperandrogenism Outpatient Clinic from November 2009 to July 2014. The exclusion criteria were patients without Ferriman-Gallwey index (FGI) and/or LAP data. We used the Rotterdam criteria for the diagnosis of PCOS. All patients underwent medical assessment followed by measurement and recording of anthropometric data and the laboratory tests for measurement of the following: thyroid-stimulating hormone, follicle-stimulating hormone, prolactin, total testosterone, sex hormone binding globulin, 17-α-hydroxyprogesterone (follicular phase), glycohemoglobin A1c, and basal insulin. In addition, the subjects underwent lipid profiling and oral glucose tolerance tests. Other laboratory measurements were determined according to clinical criteria. LAP and the homeostatic model assessment index (HOMA-IR) were calculated using the data obtained. We divided patients into two groups: the PCOS group with normal LAP (< 34.5) and the PCOS group with altered LAP (> 34.5) to compare the occurrence of hirsutism. For statistical analysis, we used SPSS Statistics for Windows(r) and Microsoft Excel programs, with descriptive (frequencies, percentages, means, and standard deviations) and comparative analyses (Student's t-test and Chi-square test). We considered relations significant when the p-value was≤0.05. Results LAP was high in most patients (n = 177; 67.3%) and the FGI indicated that 58.5% of the patients (n = 154) had hirsutism. The analysis by LAP quartiles showed a positive correlation (p = 0.04) among patients with a high FGI and an upper quartile LAP (> 79.5) when compared with those with LAP < 29.0 (lower quartile). Conclusion This study demonstrated an association between high LAP and hirsutism. The FGI could represent a simple and low-cost tool to infer an increased cardiovascular risk in women with PCOS.

Membrane properties of structurally modified ceramides : effects on lipid lateral distribution and sphingomyelin-interactions in artificial bilayer membranes

Ceramides comprise a class of sphingolipids that exist only in small amounts in cellular membranes, but which have been associated with important roles in cellular signaling processes. The influences that ceramides have on the physical properties of bilayer membranes reach from altered thermodynamical behavior to significant impacts on the molecular order and lateral distribution of membrane lipids. Along with the idea that the membrane physical state could influence the physiological state of a cell, the membrane properties of ceramides have gained increasing interest. Therefore, membrane phenomena related to ceramides have become a subject of intense study both in cellular as well as in artificial membranes. Artificial bilayers, the so called model membranes, are substantially simpler in terms of contents and spatio-temporal variation than actual cellular membranes, and can be used to give detailed information about the properties of individual lipid species in different environments. This thesis focuses on investigating how the different parts of the ceramide molecule, i.e., the N-linked acyl chain, the long-chain sphingoid base and the membrane-water interface region, govern the interactions and lateral distribution of these lipids in bilayer membranes. With the emphasis on ceramide/sphingomyelin(SM)-interactions, the relevance of the size of the SMhead group for the interaction was also studied. Ceramides with methylbranched N-linked acyl chains, varying length sphingoid bases, or methylated 2N (amide-nitrogen) and 3O (C3-hydroxyl) at the interface region, as well as SMs with decreased head group size, were synthesized and their bilayer properties studied by calorimetric and fluorescence spectroscopic techniques. In brief, the results showed that the packing of the ceramide acyl chains was more sensitive to methyl-branching in the mid part than in the distal end of the N-linked chain, and that disrupting the interfacial structure at the amide-nitrogen, as opposed to the C3-hydroxyl, had greater effect on the interlipid interactions of ceramides. Interestingly, it appeared that the bilayer properties of ceramides could be more sensitive to small alterations in the length of the long-chain base than what was previously reported for the N-linked acyl chain. Furthermore, the data indicated that the SM-head group does not strongly influence the interactions between SMs and ceramides. The results in this thesis illustrate the pivotal role of some essential parts of the ceramide molecules in determining their bilayer properties. The thesis provides increased understanding of the molecular aspects of ceramides that possibly affect their functions in biological membranes, and could relate to distinct effects on cell physiology.

Computer programs for analysis of droplets sprayed on water sensitive papers

The use of water-sensitive papers is an important tool for assessing the quality of pesticide application on crops, but manual analysis is laborious and time-consuming. Thus, this study aimed to evaluate and compare the results obtained from four software programs for spray droplet analysis in different scanned images of water-sensitive papers. After spraying, papers with four droplet deposition patterns (varying droplet spectra and densities) were analyzed manually and by means of the following computer programs: CIR, e-Sprinkle, DepositScan and Conta-Gotas. The diameter of the volume and number medians and the number of droplets per target area were studied. There is a strong correlation between the values measured using the different programs and the manual analysis, but there is a great difference between the numerical values measured for the same paper. Thus, it is not advisable to compare results obtained from different programs.

INFLUENCE OF THE GLYPHOSATE FORMULATIONS ON WETTABILITY AND EVAPORATION TIME OF DROPLETS ON DIFFERENT TARGETS

ABSTRACTEfficiency of weed control can be increased if the herbicide formulation provides higher target coverage and evaporation time that enable an adequate distribution of herbicide on the target plant, allowing the absorption to continue even after the droplets evaporation. The aim of this research was to assess the influence of glyphosate formulations on the wetted area and evaporation time of droplets on different targets. Tests were conducted with droplets sizing from 500 μm containing three formulations of glyphosate (isopropylamine salt, ammonium salt and potassium salt) deposited on three surfaces, two leaves (Bidens pilosa and Cenchrus echinatus) and glass slides. Sequential images analyses were used to quantify the evaporation time and the wetted area. An experimental system was utilized that was composed of a droplet generator, a stereo microscope with a camera to capture images, as well as an environmental chamber controlled for temperature and relative humidity. The kind of glyphosate formulations and target surfaces are crucial in the wetted area and evaporation time. The isopropylamine salt decreased the wetted area and evaporation time when compared with ammonium salt and potassium salt for all the surfaces deposited on. Bidens pilosa allows an increased wetted area for all the glyphosate formulations when compared to Cenchrus echinatus and glass slides.

Application Volumes and Sizes of Droplets for the Application of Diquat Herbicide in the Control of Eichhornia crassipes

The objective of this study was to evaluate the efficiency of application and the efficacy of control of water hyacinth (Eichhornia crassipes) with the use of the diquat herbicide done with two application volumes associated to three droplets classes. Three experiments were conducted; in the first, the application efficiency was evaluated; in the second, the control efficiency and; in the third, the droplet spectrum. They were conducted in a completely randomized design with five, four and six replicates, respectively. The treatments were arranged in a 2 x 3 factorial design, with two application volumes (100 and 200 L ha-1) and three droplets classes (fine, extremely coarse and ultra-coarse) to the first and second experiment and the third comprised two diquat concentrations in spray solution (2 and 4 g i.a. L-1) and three droplets classes (fine, extremely coarse and ultra-coarse). The application efficiency was determined by the coverage by droplets, spray deposition and active ingredient of the herbicide (diquat). The efficacy was measured by the control and the percentage of plants with regrowth at 50 days after application. The spectrum of droplets produced per each nozzle model used to obtain the droplets classes were analyzed. According to the parameters analyzed, using the droplets classes extremely thick and ultra thick can provide greater certainty in the application of diquat in the aquatic environment associated with the deposition of the active and sufficient coverage to control Eichhornia crassipes with both application volumes

Inhibition of lipid peroxidation and iron (II)-dependent DNA damage by extracts of Pothomorphe peltata (L.) Miq

Leaves of Pothomorphe peltata (L.) Miq. (Piperaceae) are used locally as anti-inflammatory, antipyretic, hepatoprotective and diuretic infusions and to treat external ulcers and local infections in several parts of the Peruvian, Bolivian and Brazilian Amazon region. The antioxidant activity of different extracts of P. peltata was studied using the hydroperoxide-initiated chemiluminescence assay in liver homogenates, and the methanolic extract was found to have the highest antioxidant activity, with an IC50 = 4 µg/ml. Aqueous and dichloromethane extracts did not show antioxidant activity. The extracts were further evaluated using the thiobarbituric acid-reactive substances (TBARS) assay. Finally, an assay of DNA sugar damage induced by Fe (II) salt was used to determine the capacity of the extracts to suppress the oxidative degradation of DNA. All the extracts showed antioxidant activity in the latter two bioassays. The methanolic extract showed the highest activity in reducing oxidative damage to DNA, with an IC50 = 5 µg/ml. Since this extract was highly effective in reducing chemiluminescence and DNA damage, and because the latter activity could be due to the presence of compounds that bind to DNA, DNA-binding activity was studied using the DNA-methyl green (DNA-MG) bioassay. A 30% decrease in the initial absorbance of DNA-MG complex was observed in the methanolic extract at 1000 µg/ml, suggesting the presence of compounds that bind to genetic material. No DNA-binding activity was observed in the aqueous or dichloromethane extracts