Experimental designs for optimizing the purification of immunoglobulin G by mixed-mode chromatography.

The main aim of this study was to define the optimal adsorption and elution conditions for the purification of human immunoglobulin G (IgG) by mixed-mode chromatography using the multimodal resin Capto MMC. To this end, Central Composite Experimental Design (ED) was performed for both the adsorption and desorption stages. In the first case, the conditions were systematically studied in batch mode while in the latter case, these were performed in column. For both studies, the experimental design was conducted using high-purity human IgG samples. Buffer pH and concentration as well as the salt concentration were the parameters under study in the ED. Adsorption kinetics and equilibrium experiments were performed under the best conditions defined in the ED (phosphate buffer 60 mmol/L, pH 6.75, no salt). The equilibrium experimental data were fit to the Langmuir equation, with maximum uptake qmax equal to 549.2 mg/g. The qmax value found for IgG in Capto MMC was quite high as compared to other chromatographic techniques that employ single modes of interaction. Regarding elution, the best conditions were obtained with acetate buffer (56.40 mmol/L), pH 5.2 and 0.2 mol/L NaCl. An ultimate recovery of 46.96% for high-purity IgG was achieved. Thus, the effectiveness of Capto MMC for IgG adsorption and recovery could be confirmed. Moreover, electrophoretic runs in the human serum indicated that although co-elution of HSA and IgG proteins occurs, substantial HSA removal and a high IgG recovery were achieved in the elution step.

Physicochemical characterization and antioxidant activity of decolorized Moringa oleifera Lam leaf flour

BACKGROUND: Maringa oleifera leaves are rich in antioxidant substances; however, when lyophilized leaves were used in flour form in meat products, they presented no antioxidant effect and even accelerated the oxidation process of the product. Thus, the objective of this study was to evaluate the effect of chlorophyll extraction on the physicochemical composition and antioxidant activity of Moringa leaves. METHODS: Moringa leaves were dried and ground in order to obtain uniform flour. A treatment using chlorophyll extraction (decolorized) was tested versus a control treatment(non-decolorized) for proximate composition, instrumental color, and antioxidant activity using ANOVA followed by Tukey'stest. RESULTS: Higher crude fiber, ash, and protein contents were observed for decolorized flour (19.41 and 38.13%, 11.87 and14.02%, and 28.81 and 31.33%, respectively) when compared to those for the control. Chlorophyll extraction significantly affected (p< 0.05) the instrumental color of the leaves flour. The half maximal effective concentration (EC50) of both decolorized and control flour was 3.74 and 4.30 mg/L, respectively. The equivalent of antioxidant per gramof non-decolorized leaves was higher than that observed for the decolorized leaves (0.36 and 0.32 g/g DPPH, respectively). The antioxidant activity (AA%) of the extract from non-decolorized leaves was higher in the concentrations of 5 and 2.5 mg/0.1 mL, while the decolorized leaves was higher in the extract concentration 5 and 2 mg/0.1 ml. CONCLUSION: The decolorization process affected the chemical composition and color of Moringa oleifera leaves flours however did not improve its antioxidant activity

Aflatoxins ingestion and canine mammary tumors: There is an association?

The aim of this study was to determine the presence of mycotoxins on dogs feed and to explore the potential association between mycotoxins exposure and the chance of mamary tumors in a case-control study. The study included 256 female dogs from a hospital population, 85 with mammary tumors (case group) and 171 without mammary tumors (control group). An epidemiological questionnaire was applied to both groups, and the data were analyzed by the EpiInfo statistical package. For the study, 168 samples of the feed offered to dogs were analyzed for the presence of aflatoxins, fumonisins and zearalenone by high-performance liquid chromatography. Mycotoxins were found in 79 samples (100%) in the case group and 87/89 (97.8%) in the control group. Mycotoxins were detected in all types of feed, regardless feed quality. Level of aflatoxin B1 (p = 0.0356, OR = 2.74, 95%, CI 1.13 to 6.60), aflatoxin G1 (AFG1) (p = 0.00007, OR = 4.60, 95%, CI = 2.16 to 9.79), and aflatoxin G2 (AFG2) (p = 0.0133, OR = 9.91, 95%, CI 1.21 to 81.15) were statistically higher in case of mammary cancer. In contrast, neutering was a protective factor for mammary cancer (p = 0.0004, OR = 0.32, 95%, CI = 0.17 to 0.60).

Cytotoxicity and expression of genes involved in the cellular stress response and apoptosis in mammalian fibroblast exposed to cotton cellulose nanofibers.

Cellulose nanofibers (CNF) have mechanical properties that make them very attractive for applications in the construction of polymeric matrices, drug delivery and tissue engineering. However, little is known about their impact on mammalian cells. The objective of this study was to evaluate the cytotoxicity of CNF and their effect on gene expression of fibroblasts cultured in vitro. The morphology of CNF was analyzed by transmission electron microscopy and the surface charge by Zeta potential. Cell viability was analyzed by flow cytometry assay and gene expression of biomarkers focused on cell stress response such as Heat shock protein 70.1 (HSP70.1) and Peroxiredoxin 1 (PRDX1) and apoptosis as B-cell leukemia (BCL-2) and BCL-2 associated X protein (BAX) by RT-PCR assay. Low concentrations of CNF (0.02-100 µg ml(-1)) did not cause cell death; however, at concentrations above 200 µg ml(-1), the nanofibers significantly decreased cell viability (86.41 ± 5.37%). The exposure to high concentrations of CNF (2000 and 5000 µg ml(-1)) resulted in increased HSP70.1, PRDX1 and BAX gene expression. The current study concludes that, under the conditions tested, high concentrations (2000 and 5000 µg ml(-1)) of CNF cause decreased cell viability and affect the expression of stress- and apoptosis-associated molecular markers.

Cellulose micro/nanofibres from Eucalyptus kraft pulp: preparation and properties.

There is growing interest in cellulose nanofibres from renewable sources for several industrial applications. However, there is a lack of information about one of the most abundant cellulose pulps: bleached Eucalyptus kraft pulp. The objective of the present work was to obtain Eucalyptus cellulose micro/nanofibres by three different processes, namely: refining, sonication and acid hydrolysis of the cellulose pulp. The refining was limited by the low efficiency of isolated nanofibrils, while sonication was more effective for this purpose. However, the latter process occurred at the expense of considerable damage to the cellulose structure. The whiskers obtained by acid hydrolysis resulted in nanostructures with lower diameter and length, and high crystallinity. Increasing hydrolysis reaction time led to narrower and shorter whiskers, but increased the crystallinity index. The present work contributes to the different widespread methods used for the production of micro/nanofibres for different applications.

[Poliomyelitis in Sergipe]. / A poliomielite em Sergipe.

A retrospective study of poliomyelitis in Sergipe, Northeast of Brazil, is presented by the authors. The study was divided in three periods, taking in consideration the notification rate of positive cases and emphasizing the period from 1979 to 1989 through the study of 159 consecutive cases. The following information was gathered for each case: sex, age, origin, former immunization status and clinical development. Also evaluated were annual incidence, relationship of incidence/vaccinal coverage and geographic distribution. Comments were made about the change in the wild poliovirus circulation (P1 to P3) and about epidemiological outbreaks occurred in 1984 and 1986, and problems related to the lack of immunity in children with complete vaccinal scheme. Poliomyelitis was considered to be controlled in the State of Sergipe but the necessity of maintenance of effective epidemiological vigilance for all cases of acute and flabby paralysis in children under 14 years is emphasized.