Density, proportion, and dendritic coverage of retinal ganglion cells of the common marmoset (Callithrix jacchus jacchus)

We performed a quantitative analysis of M and P cell mosaics of the common-marmoset retina. Ganglion cells were labeled retrogradely from optic nerve deposits of Biocytin. The labeling was visualized using horseradish peroxidase (HRP) histochemistry and 3-3'diaminobenzidine as chromogen. M and P cells were morphologically similar to those found in Old- and New-World primates. Measurements were performed on well-stained cells from 4 retinas of different animals. We analyzed separate mosaics for inner and outer M and P cells at increasing distances from the fovea (2.5-9 mm of eccentricity) to estimate cell density, proportion, and dendritic coverage. M cell density decreased towards the retinal periphery in all quadrants. M cell density was higher in the nasal quadrant than in other retinal regions at similar eccentricities, reaching about 740 cells/mm² at 2.5 mm of temporal eccentricity, and representing 8-14% of all ganglion cells. P cell density increased from peripheral to more central regions, reaching about 5540 cells/mm² at 2.5 mm of temporal eccentricity. P cells represented a smaller proportion of all ganglion cells in the nasal quadrant than in other quadrants, and their numbers increased towards central retinal regions. The M cell coverage factor ranged from 5 to 12 and the P cell coverage factor ranged from 1 to 3 in the nasal quadrant and from 5 to 12 in the other quadrants. These results show that central and peripheral retinal regions differ in terms of cell class proportions and dendritic coverage, and their properties do not result from simply scaling down cell density. Therefore, differences in functional properties between central and peripheral vision should take these distinct regional retinal characteristics into account.

Peripheral markers of oxidative stress in chronic mercuric chloride intoxication

The present study was designed to evaluate the time course changes in peripheral markers of oxidative stress in a chronic HgCl2 intoxication model. Twenty male adult Wistar rats were treated subcutaneously daily for 30 days and divided into two groups of 10 animals each: Hg, which received HgCl2 (0.16 mg kg-1 day-1), and control, receiving the same volume of saline solution. Blood was collected at the first, second and fourth weeks of Hg administration to evaluate lipid peroxidation (LPO), total radical trapping antioxidant potential (TRAP), and superoxide dismutase (Cu,Zn-SOD), glutathione peroxidase (GPx), glutathione-S-transferase (GST), and catalase (CAT). HgCl2 administration induced a rise (by 26%) in LPO compared to control (143 ± 10 cps/mg hemoglobin) in the second week and no difference was found at the end of the treatment. At that time, GST and GPx were higher (14 and 24%, respectively) in the Hg group, and Cu,Zn-SOD was lower (54%) compared to control. At the end of the treatment, Cu,Zn-SOD and CAT were higher (43 and 10%, respectively) in the Hg group compared to control (4.6 ± 0.3 U/mg protein; 37 ± 0.9 pmol/mg protein, respectively). TRAP was lower (69%) in the first week compared to control (43.8 ± 1.9 mM Trolox). These data provide evidence that HgCl2 administration is accompanied by systemic oxidative damage in the initial phase of the process, which leads to adaptive changes in the antioxidant reserve, thus decreasing the oxidative injury at the end of 30 days of HgCl2 administration. These results suggest that a preventive treatment with antioxidants would help to avoid oxidative damage in subjects with chronic intoxication.

Effect of Ginkgo biloba on the reproductive outcome and oxidative stress biomarkers of streptozotocin-induced diabetic rats

The aim of the present study was to evaluate the effect of Ginkgo biloba treatment (EGb 761, 200 mg kg-1 day-1) administered from day 0 to 20 of pregnancy on maternal reproductive performance and on the maternal and fetal liver antioxidant systems of streptozotocin-induced diabetic Wistar rats. On day 21 of pregnancy, the adult rats (weighing approximately 250 ± 50 g, minimum number = 13/group) were anesthetized to obtain maternal and fetal liver samples for superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and total glutathione (GSH-t) determinations. The uterus was weighed with its contents. The diabetic (G3) and treated diabetic (G4) groups of rats presented significant maternal hyperglycemia, reduced term pregnancy rate, impaired maternal reproductive outcome and fetal-placental development, decreased GSH-Px (G3 = G4 = 0.6 ± 0.2) and SOD (G3 = 223.0 ± 84.7; G4 = 146.1 ± 40.8), and decreased fetal CAT activity (G3 = 22.4 ± 10.6; G4 = 34.4 ± 14.1) and GSH-t (G3 = G4 = 0.3 ± 0.2), compared to the non-diabetic groups (G1, untreated control; G2, treated). For G1, maternal GSH-Px = 0.9 ± 0.2 and SOD = 274.1 ± 80.3; fetal CAT = 92.6 ± 82.7 and GSH-t = 0.6 ± 0.5. For G2, G. biloba treatment caused no toxicity and did not modify maternal or fetal-placental data. EGb 761 at the nontoxic dose used (200 mg kg-1 day-1), failed to modify the diabetes-associated increase in maternal glycemia, decrease in pregnancy rate, decrease in antioxidant enzymes, and impaired fetal development when the rats were treated throughout pregnancy (21 days).

Antioxidant responses of Laeonereis acuta (Polychaeta) after exposure to hydrogen peroxide

The effects of H2O2 were evaluated in the estuarine worm Laeonereis acuta (Polychaeta, Nereididae) collected at the Patos Lagoon estuary (Southern Brazil) and maintained in the laboratory under controlled salinity (10 psu diluted seawater) and temperature (20°C). The worms were exposed to H2O2 (10 and 50 µM) for 4, 7, and 10 days and the following variables were determined: oxygen consumption, catalase (CAT) and glutathione peroxidase activity in both the supernatant and pellet fractions of whole body homogenates. The concentrations of non-protein sulfhydryl and lipid peroxides (LPO) were also measured. The oxygen consumption response was biphasic, decreasing after 4 days and increasing after 7 and 10 days of exposure to 50 µM H2O2 (P < 0.05). At the same H2O2 concentration, CAT activity was lower (P < 0.05) in the pellet fraction of worms exposed for 10 days compared to control. Non-protein sulfhydryl concentration and glutathione peroxidase activity were not affected by H2O2 exposure. After 10 days, LPO levels were higher (P < 0.05) in worms exposed to 50 µM H2O2 compared to control. The reduction in the antioxidant defense was paralleled by oxidative stress as indicated by higher LPO values (441% compared to control). The reduction of CAT activity in the pellet fraction may be related to protein oxidation. These results, taken together with previous findings, suggest that the worms were not able to cope with this H2O2 concentration.

Determination of low tetanus or diphtheria antitoxin titers in sera by a toxin neutralization assay and a modified toxin-binding inhibition test

A method for the screening of tetanus and diphtheria antibodies in serum using anatoxin (inactivated toxin) instead of toxin was developed as an alternative to the in vivo toxin neutralization assay based on the toxin-binding inhibition test (TOBI test). In this study, the serum titers (values between 1.0 and 19.5 IU) measured by a modified TOBI test (Modi-TOBI test) and toxin neutralization assays were correlated (P < 0.0001). Titers of tetanus or diphtheria antibodies were evaluated in serum samples from guinea pigs immunized with tetanus toxoid, diphtheria-tetanus or triple vaccine. For the Modi-TOBI test, after blocking the microtiter plates, standard tetanus or diphtheria antitoxin and different concentrations of guinea pig sera were incubated with the respective anatoxin. Twelve hours later, these samples were transferred to a plate previously coated with tetanus or diphtheria antitoxin to bind the remaining anatoxin. The anatoxin was then detected using a peroxidase-labeled tetanus or diphtheria antitoxin. Serum titers were calculated using a linear regression plot of the results for the corresponding standard antitoxin. For the toxin neutralization assay, L+/10/50 doses of either toxin combined with different concentrations of serum samples were inoculated into mice for anti-tetanus detection, or in guinea pigs for anti-diphtheria detection. Both assays were suitable for determining wide ranges of antitoxin levels. The linear regression plots showed high correlation coefficients for tetanus (r² = 0.95, P < 0.0001) and for diphtheria (r² = 0.93, P < 0.0001) between the in vitro and the in vivo assays. The standardized method is appropriate for evaluating titers of neutralizing antibodies, thus permitting the in vitro control of serum antitoxin levels.

Normal flow-mediated vasodilatation of the brachial artery and carotid artery intima-media thickness in subclinical hypothyroidism

Subclinical hypothyroidism (SHT) is a disease for which exact therapeutic approaches have not yet been established. Previous studies have suggested an association between SHT and coronary heart disease. Whether this association is related to SHT-induced changes in serum lipid levels or to endothelial dysfunction is unclear. The aim of this study was to determine endothelial function measured by the flow-mediated vasodilatation of the brachial artery and the carotid artery intima-media thickness (IMT) in a group of women with SHT compared with euthyroid subjects. Triglycerides, total cholesterol, HDL-C, LDL-C, apoprotein A (apo A), apo B, and lipoprotein(a) were also determined. Twenty-one patients with SHT (mean age: 42.4 ± 10.8 years and mean thyroid-stimulating hormone (TSH) levels: 8.2 ± 2.7 µIU/mL) and 21 euthyroid controls matched for body mass index, age and atherosclerotic risk factors (mean age: 44.2 ± 8.5 years and mean TSH levels: 1.4 ± 0.6 µIU/mL) participated in the study. Lipid parameters (except HDL-C and apo A, which were lower) and IMT values were higher in the common carotid and carotid bifurcation of SHT patients with positive serum thyroid peroxidase antibodies (TPO-Ab) (0.62 ± 0.2 and 0.62 ± 0.16 mm for the common carotid and carotid bifurcation, respectively) when compared with the negative TPO-Ab group (0.55 ± 0.24 and 0.58 ± 0.13 mm, for common carotid and carotid bifurcation, respectively). The difference was not statistically significant. We conclude that minimal thyroid dysfunction had no adverse effects on endothelial function in the population studied. Further investigation is warranted to assess whether subclinical hypothyroidism, with and without TPO-Ab-positive serology, has any effect on endothelial function.

Liver lipid peroxidation and antioxidant capacity in cerulein-induced acute pancreatitis

The aim of this study was to evaluate the role of oxidative damage in pancreatitis-induced hepatic injury. Thirty-five rats were divided into five groups (each of 7 rats): control, cerulein (100 µg/kg body weight), cerulein and pentoxifylline (12 mg/kg body weight), cerulein plus L-NAME (10 mg/kg body weight) and cerulein plus L-arginine (160 mg/kg body weight). The degree of hepatic cell degeneration differed significantly between groups. Mean malondialdehyde levels were 7.00 ± 2.29, 20.89 ± 10.13, 11.52 ± 4.60, 18.69 ± 8.56, and 8.58 ± 3.68 nmol/mg protein for the control, cerulein, pentoxifylline, L-NAME, and L-arginine groups, respectively. Mean catalase activity was 3.20 ± 0.83, 1.09 ± 0.35, 2.05 ± 0.91, 1.70 ± 0.60, and 2.85 ± 0.47 U/mg protein for the control, cerulein, pentoxifylline, L-NAME, and L-arginine groups, respectively, and mean glutathione peroxidase activity was 0.72 ± 0.25, 0.33 ± 0.09, 0.37 ± 0.04, 0.34 ± 0.07 and 0.42 ± 0.1 U/mg protein for the control, cerulein, pentoxifylline, L-NAME, and L-arginine groups, respectively. Cerulein-induced liver damage was accompanied by a significant increase in tissue malondialdehyde levels (P < 0.05) and a significant decrease in catalase (P < 0.05) and GPx activities (P < 0.05). L-arginine and pentoxifylline, but not L-NAME, protected against this damage. Oxidative injury plays an important role not only in the pathogenesis of AP but also in pancreatitis-induced hepatic damage.

Effect of (-)-∆9-tetrahydrocannabinoid on the hepatic redox state of mice

(-)-∆9-Tetrahydrocannabinol (∆9-THC), a psychoactive component of marijuana, has been reported to induce oxidative damage in vivo and in vitro. In this study, we administered ∆9-THC to healthy C57BL/6J mice aged 15 weeks in order to determine its effect on hepatic redox state. Mice were divided into 3 groups: ∆9-THC (N = 10), treated with 10 mg/kg body weight ∆9-THC daily; VCtrl (N = 10), treated with vehicle [1:1:18, cremophor EL® (polyoxyl 35 castor oil)/ethanol/saline]; Ctrl (N = 10), treated with saline. Animals were injected ip twice a day with 5 mg/kg body weight for 10 days. Lipid peroxidation, protein carbonylation and DNA oxidation were used as biomarkers of oxidative stress. The endogenous antioxidant defenses analyzed were glutathione (GSH) levels as well as enzyme activities of superoxide dismutase, catalase, glutathione S-transferase, glutathione reductase, and glutathione peroxidase (GPx) in liver homogenates. The levels of mRNA of the cannabinoid receptors CB1 and CB2 were also monitored. Treatment with ∆9-THC did not produce significant changes in oxidative stress markers or in mRNA levels of CB1 and CB2 receptors in the liver of mice, but attenuated the increase in the selenium-dependent GPx activity (Δ9-THC: 8%; VCtrl: 23% increase) and the GSH/oxidized GSH ratio (Δ9-THC: 61%; VCtrl: 96% increase), caused by treatment with the vehicle. Δ9-THC administration did not show any harmful effects on lipid peroxidation, protein carboxylation or DNA oxidation in the healthy liver of mice but attenuated unexpected effects produced by the vehicle containing ethanol/cremophor EL®.

Evidence for eosinophil recruitment, leukotriene B4 production and mast cell hyperplasia following Toxocara canis infection in rats

It is well known that eosinophilia is a key pathogenetic component of toxocariasis. The objective of the present study was to determine if there is an association between peritoneal and blood eosinophil influx, mast cell hyperplasia and leukotriene B4 (LTB4) production after Toxocara canis infection. Oral inoculation of 56-day-old Wistar rats (N = 5-7 per group) with 1000 embryonated eggs containing third-stage (L3) T. canis larvae led to a robust accumulation of total leukocytes in blood beginning on day 3 and peaking on day 18, mainly characterized by eosinophils and accompanied by higher serum LTB4 levels. At that time, we also noted increased eosinophil numbers in the peritoneal cavity. In addition, we observed increased peritoneal mast cell number in the peritoneal cavity, which correlated with the time course of eosinophilia during toxocariasis. We also demonstrated that mast cell hyperplasia in the intestines and lungs began soon after the T. canis larvae migrated to these compartments, reaching maximal levels on day 24, which correlated with the complete elimination of the parasite. Therefore, mast cells appear to be involved in peritoneal and blood eosinophil infiltration through an LTB4-dependent mechanism following T. canis infection in rats. Our data also demonstrate a tight association between larval migratory stages and intestinal and pulmonary mast cell hyperplasia in the toxocariasis model.

Protective effects of organoselenium compounds against methylmercury-induced oxidative stress in mouse brain mitochondrial-enriched fractions

We evaluated the potential neuroprotective effect of 1-100 µM of four organoselenium compounds: diphenyl diselenide, 3’3-ditri-fluoromethyldiphenyl diselenide, p-methoxy-diphenyl diselenide, and p-chloro-diphenyl diselenide, against methylmercury-induced mitochondrial dysfunction and oxidative stress in mitochondrial-enriched fractions from adult Swiss mouse brain. Methylmercury (10-100 µM) significantly decreased mitochondrial activity, assessed by MTT reduction assay, in a dose-dependent manner, which occurred in parallel with increased glutathione oxidation, hydroperoxide formation (xylenol orange assay) and lipid peroxidation end-products (thiobarbituric acid reactive substances, TBARS). The co-incubation with diphenyl diselenide (100 µM) completely prevented the disruption of mitochondrial activity as well as the increase in TBARS levels caused by methylmercury. The compound 3’3-ditrifluoromethyldiphenyl diselenide provided a partial but significant protection against methylmercury-induced mitochondrial dysfunction (45.4 ± 5.8% inhibition of the methylmercury effect). Diphenyl diselenide showed a higher thiol peroxidase activity compared to the other three compounds. Catalase blocked methylmercury-induced TBARS, pointing to hydrogen peroxide as a vector during methylmercury toxicity in this model. This result also suggests that thiol peroxidase activity of organoselenium compounds accounts for their protective actions against methylmercury-induced oxidative stress. Our results show that diphenyl diselenide and potentially other organoselenium compounds may represent important molecules in the search for an improved therapy against the deleterious effects of methylmercury as well as other mercury compounds.

Short-term levosimendan treatment protects rat testes against oxidative stress

The objective of this study was to evaluate the effect of short-term levosimendan exposure on oxidant/antioxidant status and trace element levels in the testes of rats under physiological conditions. Twenty male Wistar albino rats were randomly divided into two groups of 10 animals each. Group 1 was not exposed to levosimendan and served as control. Levosimendan (12 µg/kg) diluted in 10 mL 0.9% NaCl was administered intraperitoneally to group 2. Animals of both groups were sacrificed after 3 days and their testes were harvested for the determination of changes in tissue oxidant/antioxidant status and trace element levels. Tissue malondialdehyde (MDA) was significantly lower in the levosimendan group (P < 0.001) than in the untreated control group and superoxide dismutase and glutathione peroxidase (GSH-Px) levels were significantly higher in the levosimendan group (P < 0.001). Carbonic anhydrase, catalase and GSH levels were not significantly different from controls. Mg and Zn levels of testes were significantly higher (P < 0.001) and Co, Pb, Cd, Mn, and Cu were significantly lower (P < 0.001) in group 2 compared to group 1. Fe levels were similar for the two groups (P = 0.94). These results suggest that 3-day exposure to levosimendan induced a significant decrease in tissue MDA level, which is a lipid peroxidation product and an indicator of oxidative stress, and a significant increase in the activity of an important number of the enzymes that protect against oxidative stress in rat testes.

Lipid peroxidation, detoxification capacity, and genome damage in mice after transplacental exposure to pharmaceutical drugs

Data on genome damage, lipid peroxidation, and levels of glutathione peroxidase (GPX) in newborns after transplacental exposure to xenobiotics are rare and insufficient for risk assessment. The aim of the current study was to analyze, in an animal model, transplacental genotoxicity, lipid peroxidation, and detoxification disturbances caused by the following drugs commonly prescribed to pregnant women: paracetamol, fluconazole, 5-nitrofurantoin, and sodium valproate. Genome damage in dams and their newborn pups transplacentally exposed to these drugs was investigated using the in vivo micronucleus (MN) assay. The drugs were administered to dams intraperitoneally in three consecutive daily doses between days 12 and 14 of pregnancy. The results were correlated, with detoxification capacity of the newborn pups measured by the levels of GPX in blood and lipid peroxidation in liver measured by malondialdehyde (HPLC-MDA) levels. Sodium valproate and 5-nitrofurantoin significantly increased MN frequency in pregnant dams. A significant increase in the MN frequency of newborn pups was detected for all drugs tested. This paper also provides reference levels of MDA in newborn pups, according to which all drugs tested significantly lowered MDA levels of newborn pups, while blood GPX activity dropped significantly only after exposure to paracetamol. The GPX reduction reflected systemic oxidative stress, which is known to occur with paracetamol treatment. The reduction of MDA in the liver is suggested to be an unspecific metabolic reaction to the drugs that express cytotoxic, in particular hepatotoxic, effects associated with oxidative stress and lipid peroxidation.

Características químicas dos mingaus desidratados de arroz e soja

O presente trabalho teve por objetivo caracterizar quimicamente os mingaus desidratados de arroz e soja nas respectivas proporções 100:0, 90:10, 80:20, 70:30, 60:40 e 50:50% e verificar a possibilidade do uso de alguns destes mingaus como ingredientes na formulação de alimentos infantis com base nos resultados discutidos. O processo utilizado para sua obtenção foi decorticagem dos grãos de soja, branqueamento, desintegração e homogeneização do arroz e soja, assim como secagem por atomização. A caracterização química foi realizada através das seguintes determinações: composição centesimal, composição de minerais e de aminoácidos, e atividade do inibidor de tripsina. Com o aumento das proporções de soja (de 0 a 50%), os mingaus desidratados tiveram aumento nos teores de proteína, extrato etéreo, cinzas, fibra bruta, fósforo, cálcio, potássio, magnésio, ferro, cobre, zinco, selênio, manganês e molibdênio, porém diminuição nos teores de carboidrato, sódio e cromo. Contudo, os valores de cobalto não foram alterados. Os teores de potássio, magnésio, ferro e cobre foram altos e os teores de cromo, selênio, manganês e molibdênio foram suficientes em 100g de mingaus desidratados de arroz e soja com 40 e 50% de soja, atendendo 100% das recomendações da RDA para lactentes, podendo estes formulados para alimentos infantis. Houve uma melhoria nos escores de aminoácidos essenciais com as crescentes proporções de soja, exceto para os aminoácidos sulfurados. A composição em aminoácidos foi adequada e comparável ao padrão da FAO/WHO para lactentes, exceto para lisina e metionina. Em relação a lisina, os mingaus desidratados com 30, 40 e 50% de soja mostraram os maiores escores para pré-escolares, não havendo deficiência para escolares. Por outro lado, a metionina não foi deficiente para pré-escolares e escolares. A atividade residual do inibidor de tripsina não foi observada nos mingaus desidratados estudados.

PRODUÇÃO DE IMUNORREAGENTES PARA USO EM UM TESTE IMUNOENZIMÁTICO DE DETECÇÃO DE SALMONELLA EM ALIMENTOS

O objetivo deste trabalho foi o desenvolvimento de imunorreagentes policlonais convenientes para uso em um teste imunoenzimático para detecção rápida de Salmonella em alimentos. Foram produzidos seis anti-soros policlonais anti-Salmonella contendo as aglutininas e, h; 1,6; i; 1,2; f,g,s e m,t. Como antígenos, foram empregadas culturas formolizadas de quatro sorotipos de Salmonella (S. Typhimurium fases 1 e 2, S. Anatum fases 1 e 2, S. Agona monofásica e S. Oranienburg monofásica) cultivadas em caldo tripticase de soja. O teste imunoenzimático utilizado foi o indireto, empregando-se anti-IgG-peroxidase como conjugado e OPD-H2O2 como sistema cromógeno. Os testes imunoenzimáticos foram conduzidos com os anti-soros policlonais individuais absorvidos e não-absorvidos, bem como empregando-se um anti-soro polivalente, correspondente a um "pool" de anti-soros absorvidos e não-absorvidos com culturas puras de Salmonella e outras enterobactérias. A absorção dos soros eliminou as reações cruzadas com todas as enterobactérias testadas nesse estudo, apresentadas tanto por alguns anti-soros individuais quanto pelo polivalente. Entre os seis anti-soros estudados, os que apresentaram melhor desempenho foram o f,g,s não-absorvido e o polivalente absorvido.

Avaliação físico-química de águas minerais comercializadas na região de Campinas, SP

Com o objetivo de avaliar a qualidade de águas minerais, foram analisadas amostras, adquiridas em supermercados, de oito fontes localizadas no Estado de São Paulo entre agosto de 1999 e maio de 2000, com coletas trimestrais. Os resultados das análises físico-químicas mostraram que as amostras possuíam, em sua maioria, composição química dentro dos limites permitidos pela legislação brasileira, exceto quatro amostras, que apresentaram resultados na análise de cor acima de 5 unidades PtCo, uma amostra com pH fora da faixa recomendada de 4,0 a 9,0 e uma amostra com alcalinidade em hidróxidos em duas épocas de análise. Os resultados obtidos para as diferentes amostras variaram de acordo com as seguintes faixas: pH de 6,39 a 9,92, alcalinidade de 0,0 a 189,1mg L-1 de bicarbonato, dureza de 0,00 a 136,00mg L-1 de carbonato de cálcio, cor de 0,0 a 9,0 unidades de PtCo, turbidez de 0,00 a 2,00 FTU de turvação, sulfato de 0,00 a 55,67mg L-1, sulfeto de 0,00 a 0,002mg L-1, cloreto de 0,00 a 23,53mg L-1, fluoreto de 0,02 a 0,8mg L-1, alumínio de 0,01 a 0,09mg L-1, bário de 0,00 a 0,26mg L-1, cálcio de 0,53 a 28,35mg L-1, crômio de 0,00 a 0,01mg L-1, ferro de 0,00 a 0,03mg L-1, potássio de 0,39 a 3,27mg L-1, sódio de 0,53 a 97,29mg L-1, magnésio de 0,00 a 9,10mg L-1, manganês de 0,00 a 0,05mg L-1, zinco de 0,00 a 0,03mg L-1, chumbo de 0,00 a 0,01mg L-1 e lítio de 0,00 a 0,02mg L-1. Os elementos cádmio, cobre e cobalto apresentaram-se abaixo dos limites de detecção dos métodos.