Raul Jorge Hernan Castro-Gomez

Analysis of peripheral T cells and the CC chemokine receptor (CCR5) delta32 polymorphism in prostate cancer patients treated with carboxymethyl-glucan (CM-G)

β-Glucan, derived from Saccharomyces cerevisiae, is a biological response modifier which affects the innate and adaptive immune responses. The CCR5 chemokine receptor is crucial for immune cell responses. In this study, the effects of the carboxymethylated form of β-glucan (CM-G) on the lymphocyte population of CCR5 genotype patients with prostate cancer (PCa), undergoing androgen deprivation therapy (ADT) was assessed. The CCR5 genotype and lymphocyte population was investigated by cytometry flow in 30 Brazilian patients with advanced PCa who were treated with CM-G for 28 days. The analysis of the CCR5 chemokine receptor revealed that the wild-type genotype Wt/Wt was present in 80% of patients, while the heterozygotic genotype Wt/delta32 was present in 20% of patients. After CM-G administration, a significant increase in CD3+, CD4+ and CD8+ T lymphocytes was observed in patients who displayed the wild-type genotype for the CCR5 chemokine receptor. No association was found between patients age or length of ADT and increase in T lymphocyte cells. The results demonstrated the ability of CM-G to stimulate CD4+ and CD8+ T cells in the peripheral blood of patients carrying a wild-type CCR5 genotype, suggesting an interaction between immunomodulation by CM-G and the CCR5 receptor.

Saccharomyces uvarum mannoproteins stimulate a humoral immune response in mice

Yeasts discarded in industrial processes can be used as a nutritional supplement and to extract cellular components with biotechnological aims. In this study, the humoral immune response of Swiss mice treated with mannoproteins (MP) from the yeast Saccharomyces uvarum was evaluated. The mice were treated with MPs at different doses and times and inoculated with 2% sheep red blood cells. An increase in total Ig in mice treated with 100 μg of MP at the time of immunization or 24 h before was observed in the primary immune response; in the secondary immune response, an increase was observed in total Ig values for all groups, and an increase of IgG was observed in the mice treated with MPs (100 μg) at the time of immunization or 24 h before. These results show that S. uvarum MPs present an immunostimulatory action on the humoral immune response in mice.

Avaliação da mutagenicidade e antimutagenicidade de um biopolímero extraído do microorganismo Agrobacterium radiobacter em camundongos Swiss

This study evaluated the mutagenic and ant mutagenic action of a biopolymer of glucose extracted from Agrobacterium radiobacter (Biopolymer of Agrobacterium radiobacter). The experiment was conducted with Swiss male mice divided into eight groups. Treatment with the biopolymer was performed in a single dose by gavage at a dose of concomitant phosphate buffer groups in the evaluation of mutagenicity, or the agent of inducing DNA damage, cyclophosphamide, the concentration of 50 mg/kg (body weight --b.w.), in groups of assessment ant mutagenic. We used the micronucleus test in peripheral blood. The blood sample was held 24 and 48 h after application of the test substances. Statistical analysis showed that the biopolymer has no mutagenic activity and it is effective in preventing damage to DNA. The percentages of damage reduction in groups of ant mutagenic were 83.9%, 89.1% and 103.1% in 24 h and 101.24%, 98.14% and 120.64% at doses of 48 to 75, 150 and 300 mg/kg (b.w.) respectively. The high percentage of damage reduction associated with the absence of mutagenic effects indicates the possibility of biopolymer chemoprotection action. It can also be considered a functional food candidate to be used as co-adjuvant chemotherapy to prevent side effects.

Utilisation of response surface methodology to optimise the culture medium for Bacillus thuringiensis subsp. israelensis

Bacillus thuringiensis israelensis (Bti) is a sporulating Gram-positive bacterium that produces protein crystals with insecticide activity against Diptera. The aim of the present work was to optimise the culture medium for this bacterium, based on mathematical and statistical concepts (factorial designs and response surface methodology). The variables studied were carbon and nitrogen source concentrations. The main response analysed was toxicity, evaluated by means of bioassay with Aedes aegypti. The nutrient sources were first selected and then optimised. Ground Bombyx mori pupae, ammonium sulphate and glucose were the most suitable sources of organic nitrogen, inorganic nitrogen and organic carbon, respectively. The toxicity of optimised medium (LC50 = 0.703 ppm, v/v) was higher than that the medium used as reference (LC50 = 3.01 ppm, v/v), which is commonly used in the laboratory culture of Bti. Besides, the optimised medium showed a cost 7.36 times less than that of an alternative medium, based on soybean flour and sugarcane molasses. Factorial design and response surface methodology were effective methods for culture medium optimisation. The results will contribute to the development of local production and utilisation of agroindustrial waste locally.

Modulation of vascular function and anti-aggregation effect induced by (1 → 3) (1 → 6)-β-d-glucan of Saccharomyces cerevisiae and its carboxymethylated derivative in rats

BACKGROUND β-D-Glucans are polysaccharides found in the cell walls of yeasts, such as Saccharomyces cerevisiae, and they have been studied because of their beneficial effects on health, mainly in terms of immunomodulation. However, information on the action of these polymers on vascular and platelet function is still scarce. This study evaluate the effect of (1 → 3) (1 → 6) β-D-glucan (βG-Sc) and its carboxymethylated derivative (CM-G) on vascular and platelet function in rats. METHODS The animals received daily oral treatments with βG-Sc (20 mg/kg) and CM-G (20 mg/kg) for eight days. Next, cytokine quantification, vascular reactivity and adenosine diphosphate (ADP)- and collagen-induced platelet aggregation studies were performed. In vitro platelet aggregation and P-selectin exposition assays were conducted using 100 and 300 μg/mL CM-G. RESULTS The CM-G-treated group had less IL-8 than did the control. In reactivity experiments, CM-G and βG-Sc treatments did not change the contractile response of the vessel induced by PHE. Moreover, only CM-G improved the vasorelaxation response to Nitroprusside (SPN, a nitric oxide donor). The in vitro aggregation studies showed that at the highest concentration (300 μg/mL), CM-G inhibited the agonist-induced platelet aggregation with an effect similar to that of acetylsalicylic acid and without affecting P-selectin exposition. The treatments with βG-Sc or CM-G inhibited the platelet aggregation stimulated by ADP, but only βG-Sc treatment was effective in affect the collagen-stimulated aggregation. CONCLUSIONS These findings suggest that CM-G modulate positively the vascular function, mainly in responses NO-dependent. CM-G and βG-Sc have an anti-aggregation effect, being CM-G more selective to ADP-induced platelet aggregation.BACKGROUND β-d-Glucans are polysaccharides found in the cell walls of yeasts, such as Saccharomyces cerevisiae, and they have been studied because of their beneficial effects on health, mainly in terms of immunomodulation. However, information on the action of these polymers on vascular and platelet function is still scarce. This study evaluate the effect of (1→3) (1→6) β-d-glucan (βG-Sc) and its carboxymethylated derivative (CM-G) on vascular and platelet function in rats. METHODS The animals received daily oral treatments with βG-Sc (20mg/kg) and CM-G (20mg/kg) for eight days. Next, cytokine quantification, vascular reactivity and adenosine diphosphate (ADP)- and collagen-induced platelet aggregation studies were performed. In vitro platelet aggregation and P-selectin exposition assays were conducted using 100 and 300μg/mL CM-G. RESULTS The CM-G-treated group had less IL-8 than did the control. In reactivity experiments, CM-G and βG-Sc treatments did not change the contractile response of the vessel induced by PHE. Moreover, only CM-G improved the vasorelaxation response to Nitroprusside (SPN, a nitric oxide donor). The in vitro aggregation studies showed that at the highest concentration (300μg/mL), CM-G inhibited the agonist-induced platelet aggregation with an effect similar to that of acetylsalicylic acid and without affecting P-selectin exposition. The treatments with βG-Sc or CM-G inhibited the platelet aggregation stimulated by ADP, but only βG-Sc treatment was effective in affect the collagen-stimulated aggregation. CONCLUSIONS These findings suggest that CM-G modulate positively the vascular function, mainly in responses NO-dependent. CM-G and βG-Sc have an anti-aggregation effect, being CM-G more selective to ADP-induced platelet aggregation.

Characterisation and microstructure of reduced-fat chicken patties made with a novel polymer from Agrobacterium radiobacter k84.

Chicken patties elaborated with a novel polymer from Agrobacterium radiobacter k84 (ARB) were characterised during 60days of frozen storage. After cooking, formulations without ARB (F0), with ARB 5 g/100 g (F5) and ARB 10 g/100 g (F10) presented 4.23%, 2.83% and 0.11% fat, respectively. No differences were observed to water holding capacity, cooking yield and shear force among formulations. Microstructural analysis showed formation of meat emulsion for F5 and gel for F10. Colour and chicken flavour decreased with increase of ARB; no difference was found for tenderness among the formulations. Overall acceptance showed higher scores for F0 when compared to F5 and F10. Lipid oxidation was not a limiting factor for stability of patties; all formulations presented suitable microbiological quality over the assessed period. These results suggest ARB as a promising fat substitute, capable of maintain the quality aspects of chicken patties, although a negative impact in colour has been found.

A Newly Isolated Carboxymethyl-Glucan (CM-G) Restores Depressed Baroreflex Sensitivity in Renovascular Hypertensive Rats

This study was designed to investigate the effects of a newly synthesized carboxymethyl-glucan (CM-G) on blood pressure (BP), baroreflex sensitivity (BRS) and sympathetic vascular modulation in renovascular hypertensive rats. Male Wistar rats were divided into four groups: Sham (n = 10); 2K1C (subjected to renal artery clipping to induce renovascular hypertension, n = 10); Sham + CM-G (treated with CM-G, n = 7) and 2K1C + CM-G (treated with CM-G, n = 7). The daily treatment with CM-G (40 mg/kg) was performed for 2 weeks. Blood pressure, heart rate (HR), systolic BP variability, baroreflex sensitivity (BRS) and sympathetic vascular tone were evaluated. After six weeks of renal artery clipping, 2K1C rats exhibited arterial hypertension (171 ± 11 vs. 118 ± 4 mmHg, p < 0.05), impaired BRS (-1.30 ± 0.10 vs. -2.59 ± 0.17 bpm.mmHg-1, p < 0.05) and enhanced sympathetic activity as shown by the hexamethonium test (-60 ± 5 vs. -33 ± 2 ΔmmHg, p < 0.05) when compared to sham rats. Oral administration of CM-G in renovascular hypertensive rats reduced hypertension (126 ± 4 vs. 171 ± 11 mmHg, p < 0.05) and improved the BRS (-2.03 ± 0.16 vs. -1.30 ± 0.10 bpm.mmHg-1, p < 0.05) in 2K1C rats when compared to placebo. Those effects seem to be caused by a reduction in sympathetic activity. The present study revealed for the first time that CM-G treatment reduces arterial hypertension and restores arterial baroreflex sensitivity via a reduction in the sympathetic tone in conscious renovascular hypertensive rats.