Use of nucleotides in weanling rats with diarrhea induced by a lactose overload: effect on the evolution of diarrhea and weight and on the histopathology of intestine, liver and spleen

Until recently, dietary sources of nucleotides were thought not to be essential for good nutrition. Certain states with higher metabolic demands may require larger amounts that cannot be provided by endogenous production. The objective of the present study was to determine the action of nucleotides on the recovery from lactose-induced diarrhea in weaned rats. Thirty-six weanling Fisher rats were divided into two groups. Group 1 received a standard diet and group 2 received a diet containing lactose in place of starch. On the 10th day, six animals per group were sacrificed for histopathological evaluation. The remaining animals were divided into two other subgroups, each with 6 animals, receiving a control diet, a control diet with nucleotides (0.05% adenosine monophosphate, 0.05% guanosine monophosphate, 0.05% cytidine monophosphate, 0.05% uridine monophosphate and 0.05% inosine monophosphate), a diet with lactose, and a diet with lactose and nucleotides. On the 32nd day of the experiment all animals were sacrificed. Animals with diarrhea weighed less than animals without diarrhea. The introduction of nucleotides did not lead to weight gain. Mean diet consumption was lower in the group that continued to ingest lactose, with the group receiving lactose plus nucleotides showing a lower mean consumption. Animals receiving lactose had inflammatory reaction and deposits of periodic acid-Schiff-positive material in intestinal, hepatic and splenic tissues. The introduction of nucleotides led to an improvement of the intestinal inflammatory reaction. In lactose-induced diarrhea, when the stimulus is maintained - lactose overload - the nucleotides have a limited action on the weight gain and on recovery of intestinal morphology, although they have a protective effect on hepatic injury and improve the inflammatory response.

Dietary cellulose has no effect on the regeneration of hemoglobin in growing rats with iron deficiency anemia

The objective of the present study was to determine the effect of cellulose on intestinal iron absorption in rats during recovery from iron deficiency anemia. Twenty-one-day-old male Wistar-EPM rats were fed an iron-free ration for two weeks to induce anemia. At 5 weeks of age, the rats were divided into two groups (both groups receiving 35 mg of elemental iron per kg diet): cellulose group (N = 12), receiving a diet containing 100 g of cellulose/kg and control (N = 12), receiving a diet containing no cellulose. The fresh weight of the feces collected over a 3-day period between the 15th and 18th day of dietary treatment was 10.7 ± 3.5 g in the group receiving cellulose and 1.9 ± 1.2 g in the control group (P<0.001). Total food intake was higher in the cellulose group (343.4 ± 22.0 g) than in the control (322.1 ± 13.1 g, P = 0.009) during the 3 weeks of dietary treatment. No significant difference was observed in weight gain (cellulose group = 132.8 ± 19.2, control = 128.0 ± 16.3 g), hemoglobin increment (cellulose group = 8.0 ± 0.8, control = 8.0 ± 1.0 g/dl), hemoglobin level (cellulose group = 12.3 ± 1.2, control = 12.1 ± 1.3 g/dl) or in hepatic iron levels (cellulose group = 333.6 ± 112.4, control = 398.4 ± 168.0 µg/g dry tissue). We conclude that cellulose does not adversely affect the regeneration of hemoglobin, hepatic iron level or the growth of rats during recovery from iron deficiency anemia.

Cytotoxicity of chlorhexidine digluconate to murine macrophages and its effect on hydrogen peroxide and nitric oxide induction

Chlorhexidine, even at low concentrations, is toxic for a variety of eukaryotic cells; however, its effects on host immune cells are not well known. We evaluated in vitro chlorhexidine-induced cytotoxicity and its effects on reactive oxygen/nitrogen intermediate induction by murine peritoneal macrophages. Thioglycollate-induced cells were obtained from Swiss mice by peritoneal lavage with 5 ml of 10 mM phosphate-buffered saline, washed twice and resuspended (10(6) cells/ml) in appropriate medium for each test. Cell preparations contained more than 95% macrophages. The cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay and the presence of hydrogen peroxide (H2O2) and nitric oxide (NO) by the horseradish peroxidase-dependent oxidation of phenol red and Griess reaction, respectively. The midpoint cytotoxicity values for 1- and 24-h exposures were 61.12 ± 2.46 and 21.22 ± 2.44 µg/ml, respectively. Chlorhexidine did not induce synthesis or liberation of reactive oxygen/nitrogen intermediates. When macrophages were treated with various sub-toxic doses for 1 h (1, 5, 10, and 20 µg/ml) and 24 h (0.5, 1, and 5 µg/ml) and stimulated with 200 nM phorbol myristate acetate (PMA) solution, the H2O2 production was not altered; however, the NO production induced by 10 µg/ml lipopolysaccharide (LPS) solution varied from 14.47 ± 1.46 to 22.35 ± 1.94 µmol/l and 13.50 ± 1.42 to 20.44 ± 1.40 µmol/l (N = 5). The results showed that chlorhexidine has no immunostimulating activity and sub-toxic concentrations did not affect the response of macrophages to the soluble stimulus PMA but can interfere with the receptor-dependent stimulus LPS.

Influence of He-Ne laser therapy on the dynamics of wound healing in mice treated with anti-inflammatory drugs

We determined the effects of helium-neon (He-Ne) laser irradiation on wound healing dynamics in mice treated with steroidal and non-steroidal anti-inflammatory agents. Male albino mice, 28-32 g, were randomized into 6 groups of 6 animals each: control (C), He-Ne laser (L), dexamethasone (D), D + L, celecoxib (X), and X + L. D and X were injected im at doses of 5 and 22 mg/kg, respectively, 24 h before the experiment. A 1-cm long surgical wound was made with a scalpel on the abdomens of the mice. Animals from groups L, D + L and X + L were exposed to 4 J (cm²)-1 day-1 of He-Ne laser for 12 s and were sacrificed on days 1, 2, or 3 after the procedure, when skin samples were taken for histological examination. A significant increase of collagen synthesis was observed in group L compared with C (168 ± 20 vs 63 ± 8 mm²). The basal cellularity values on day 1 were: C = 763 ± 47, L = 1116 ± 85, D = 376 ± 24, D + L = 698 ± 31, X = 453 ± 29, X + L = 639 ± 32 U/mm². These data show that application of L increases while D and X decrease the inflammatory cellularity compared with C. They also show that L restores the diminished cellularity induced by the anti-inflammatory drugs. We suggest that He-Ne laser promotes collagen formation and restores the baseline cellularity after pharmacological inhibition, indicating new perspectives for laser therapy aiming to increase the healing process when anti-inflammatory drugs are used.

Antinociceptive effect on mice of the hydroalcoholic fraction and (-) epicatechin obtained from Combretum leprosum Mart & Eich

Previous studies on Combretum leprosum, a tree growing in the Northeastern states of Brazil, have shown antinociceptive effects of the ethanol extract of its leaves and bark, but studies examining its constituents are rare. The objective of this study was to evaluate the antinociceptive effect of the hydroalcoholic fraction (HF) of one of its constituents, the flavonoid (-) epicatechin (EPI), administered orally to mice (20-30 g) in models of chemical nociception, and the possible mechanisms involved. Different doses of HF (62.5 to 500 mg/kg) and EPI (12.5 to 50 mg/kg) were evaluated in models of abdominal writhing, glutamate, capsaicin, and formalin in animals pretreated with different antagonists: naloxone, ondansetron, yohimbine, ketanserin, pindolol, atropine, and caffeine in the abdominal writhing test. To determine the role of nitric oxide, the animals were pretreated with L-arginine (600 mg/kg, ip) in the glutamate test. The HF was effective (P < 0.05) in all protocols at different doses and EPI was effective in the abdominal writhing, capsaicin and glutamate tests (P < 0.05) at doses of 25 and 50 mg/kg. However, in the formalin test it was only effective in the second phase at a dose of 25 mg/kg. The antinociceptive effect of HF was inhibited when HF was associated with yohimbine (0.15 mg/kg), ketanserine (0.03 mg/kg), and L-arginine (600 mg/kg), but not with the other antagonists. HF and EPI were effective in models of chemical nociception, with the suggested participation of the adrenergic, serotonergic and nitrergic systems in the antinociceptive effect of HF.

Construction of a recombinant adenovirus co-expressing truncated human prostate-specific membrane antigen and mouse 4-1BBL genes and its effect on dendritic cells

Our aim was to construct a recombinant adenovirus co-expressing truncated human prostate-specific membrane antigen (tPSMA) and mouse 4-1BBL genes and to determine its effect on dendritic cells (DCs) generated from bone marrow suspensions harvested from C57BL/6 mice for which the effect of 4-1BBL on DCs is not clear, especially during DCs processing tumor-associated antigen. Replication deficient adenovirus AdMaxTM Expression System was used to construct recombinant adenovirus Ad-tPSMA-internal ribosome entry site-mouse 4-1BBL (Ad-tPSMA-IRES-m4-1BBL) and Ad-enhanced green fluorescent protein. Day 7 proliferating DC aggregates generated from C57BL/6 mice were collected as immature DCs and further mature DCs were obtained by lipopolysaccharide activated immature DCs. After DCs were exposed to the recombinant adenovirus with 250 multiplicity of infection, the expression of tPSMA and m4-1BBL proteins were detected by Western blot, and the apoptosis and phenotype of DCs were analyzed by flow cytometry. Cytokines (IL-6 and IL-12) in the supernatant were detected by enzyme-linked immunosorbent assay (ELISA). Proliferation of T cells was detected by allogeneic mixed lymphocyte reactions. The tPSMA and m4-1BBL proteins were expressed correctly. The apoptosis rate of DCs transfected with Ad-tPSMA-IRES-m4-1BBL was 14.6%, lower than that of control DCs. The expression of co-stimulatory molecules [CD80 (81.6 ± 5.4%) and CD86 (80.13 ± 2.81%)] up-regulated in Ad-tPSMA-IRES-m4-1BBL-pulsed DCs, and the level of IL-6 (3960.2 ± 50.54 pg/mL) and IL-12 (249.57 ± 12.51 pg/mL) production in Ad-tPSMA-IRES-m4-1BBL-transduced DCs were significantly higher (P < 0.05) than those in control DCs. Ad-tPSMA-IRES-m4-1BBL induced higher T-cell proliferation (OD450 = 0.614 ± 0.018), indicating that this recombinant adenovirus can effectively enhance the activity of DCs.

Nutritional characteristics of amazonian fish fat (Colossoma macropomum) and its effect on lipid metabolism of rats fed hypercholesterolemic diets

The effects of fat from tambaqui (Colossoma macropomum), an Amazonian fish, on some nutritional and lipid parameters in rats were evaluated. Weaned Wistar rats were fed for 6 weeks with hypercholesterolemic diets containing 7.5% of soybean oil (SO), cod liver oil (CO), lard (LA), or tambaqui fat (TF). Food consumption, weight gain, and food conversion were measured weekly. Plasma triglycerides was determined at the beginning and on the 6th week of experiment. Plasma cholesterol was determined at 0, 2, 4 and 6 weeks. After the sacrifice, hepatic lipids (triglycerides and cholesterol) and plasma triglycerides, total cholesterol and HDL fractions were determined. Food consumption and weight gain were the same for all groups. There were no differences in plasma triglycerides among the four groups in the 1st and 6th weeks. Regarding the cholesterolemia, TF animals were similar to those fed SO diet, significantly lower than in LA group but higher compared to the CO group. The levels of very low density lipoprotein + low density lipoprotein (VLDL+LDL) were higher in the TF and LA groups compared to the CO and SO groups. However, TA fed animals had high-density lipoprotein (HDL) cholesterol levels higher than the CO group. The ratio (VLDL+LDL)/HDL was higher in the LA group when compared with the remaining groups. In the TA group, the triglycerides and cholesterol concentrations in the liver were similar to the SO group. It may be concluded that tambaqui fat is a good dietary source of lipids as a substitute for lard and similar to soybean oil, as far as atherosclerosis risks is concerned.

Partial substitution of nitrite by chitosan and the effect on the quality properties of pork sausages

The aim of the study was to evaluate the influence of partial nitrite replacement by chitosan on the quality of Ham Visking (a type of pork sausages). Five Ham Visking formulations were elaborated modifying the sodium nitrite (0.011; 0.016 or 0.0212%) and chitosan concentrations (0.25 or 0.5%) in the products. Sausages were stored at 4 ºC and physicochemical, microbiological, and sensorial evaluations were performed in order to estimate their shelf life. Chitosan can be used in pork sausages without affecting ensory attributes such as color although the panelists detected textural differences among the samples with chitosan, which suggests that there is some influence of deacetylation degree of chitosan on the textural behavior of sausages which still needed to be explained for a successful application of chitosan in meat products. The reduction of residual sodium nitrite did not affect the color and flavor of such products, but the use of chitosan increasedsignificantly the shelf life of sausages.

Starch edible coating of papaya: effect on sensory characteristics

The coating of papayas with Cassava Starch (CS) and carboxymethyl starch (CMS) is an alternative to extend the shelf life of these fruits. This study evaluated the effect of the three different levels of CS and CMS (1, 3, and 5%) on sensory characteristics of papayas during storage. Nine selected and trained assessors evaluated 13 sensory attributes using the Multiple Comparison Test. The appearance and flavor attributes of the papayas treated with CS and CMS were compared to the control or reference sample (R - fruit without coating) using a nine-point scale, which varied from 1: less intense than R; 5: equal to R; 9: more intense than R. The samples were coded with three digit numbers and evaluated with repetition by a panel of assessors. In general, appearance was more affected by the coatings than flavor. Fruits coated with 3 and 5% of both coatings kept the green color longer than the other coating’s concentrations, and at 5% the color of the fruits was less uniform on the last evaluation day. The 3 and 5% CS coating gave greater brightness to the fruits. 5% CMS favored the presence of fungi and damaged the fruit surface at the 14th day of storage. The CS coating at 5% presented peeled surface during all experimental time. Changes in fruits’ flavor were perceived at the 12th and 14th days of storage. A less characteristic flavor and a bitter taste were noticed in the fruits coated with CS and CMS at 5% at the 12th day of storage.

Impact of dams and irrigation schemes in Anopheline (Diptera: Culicidae) bionomics and malaria epidemiology

Irrigation schemes and dams have posed a great concern on public health systems of several countries, mainly in the tropics. The focus of the present review is to elucidate the different ways how these human interventions may have an effect on population dynamics of anopheline mosquitoes and hence, how local malaria transmission patterns may be changed. We discuss different studies within the three main tropical and sub-tropical regions (namely Africa, Asia and the Pacific and the Americas). Factors such as pre-human impact malaria epidemiological patterns, control measures, demographic movements, human behaviour and local Anopheles bionomics would determine if the implementation of an irrigation scheme or a dam will have negative effects on human health. Some examples of successful implementation of control measures in such settings are presented. The use of Geographic Information System as a powerful tool to assist on the study and control of malaria in these scenarios is also highlighted.

ORGANIC NITROGEN IN A TYPIC HAPLUDOX FERTILIZED WITH PIG SLURRY

The application of pig slurry may have a different effect on nitrogen dynamics in soil compared to mineral fertilization. Thus, the aim of this study was to determine the different forms of organic N in a Latossolo Vermelho distroférrico (Typic Hapludox) and their relationship to N uptake by crops in response to 10 years of annual application of pig slurry and mineral fertilizer. The treatments were application rates of 0, 25, 50, 100, and 200 m3 ha-1 of pig slurry, in addition to mineral fertilizer, organized in a randomized block design with four replications. The N contents were determined in the plant tissue and in the forms of total N and acid hydrolyzed fractions: ammonium-N, hexosamine-N, α-amino-N, amide-N, and unidentified-N. Annual application of pig slurry or mineral fertilizer increased the total-N content in the 0-10 cm depth layer. The main fractions of organic N in the soil were α-amino-N when pig slurry was applied and unidentified-N in the case of mineral fertilizers. Pig slurry increased the N fractions considered as labile: α-amino-N, ammonium-N, and amide-N. The increase in these labile organic N fractions in the soil through pig slurry application allows greater N uptake by the maize and oat crops in a no-tillage system.