Canine rangeliosis due to Rangelia vitalii: from first report in Brazil in 1910 to current day - a review.

Canine rangeliosis (popular names: "nambi-uvú", i.e. ``bleeding ears''; "peste de sangue", i.e. ``bleeding plague''; and "febre amarela dos cães", i.e. ``yellow fever of dogs'') is a tick-borne haemolytic and haemorrhagic disease caused by the protozoan parasite Rangelia vitalii which infects erythrocytes, leukocytes, and endothelial cells of blood capillaries. Rangelia vitalii was first reported as a novel piroplasm of dogs in 1910 in Brazil, a discovery that was met with skepticism at that time. Canine rangeliosis has been diagnosed in domestic dogs not only in Brazil but also in other South American countries (Argentina and Uruguay). Rangelia vitalii infection has also been found incidentally in Brazil in wild dogs (Cerdocyon thous, the crab-eating fox). Despite the fact that researchers in the early 1900s suggested that R. vitalii was a hitherto unidentified piroplasm that would be transmitted by the tick Amblyomma aureolatum, it was not until 2012 that these hypotheses were actually confirmed by PCR and transmission studies. Molecular studies have shown that R. vitalii is related to the Babesia sensu strictu clade, but genetically different from other morphologically similar species of Babesia that infect dogs. Another difference between Babesia spp. and R. vitalii is the ability of R. vitalii to invade endothelial cells, erythrocytes, and leukocytes. Experimental infection in dogs has successfully reproduced the clinical picture and pathology of the natural disease. In this article, epidemiology, clinical signs, laboratory findings, pathogenetic mechanisms including oxidative stress and immune response, necropsy findings, microscopic lesions, diagnosis, and treatment of canine rangeliosis are reviewed. What is currently known about this protozoal disease since its first report over a century ago is presented herein.

Quercetin protects the impairment of memory and anxiogenic-like behavior in rats exposed to cadmium: Possible involvement of the acetylcholinesterase and Na(+),K(+)-ATPase activities.

The present study investigated the effects of quercetin in the impairment of memory and anxiogenic-like behavior induced by cadmium (Cd) exposure. We also investigated possible alterations in acetylcholinesterase (AChE), Na(+),K(+)-ATPase and δ-aminolevulinate dehydratase (δ-ALA-D) activities as well as in oxidative stress parameters in the CNS. Rats were exposed to Cd (2.5mg/kg) and quercetin (5, 25 or 50mg/kg) by gavage for 45days. Animals were divided into eight groups (n=10-14): saline/control, saline/Querc 5mg/kg, saline/Querc 25mg/kg, saline/Querc 50mg/kg, Cd/ethanol, Cd/Querc 5mg/kg, Cd/Querc 25mg/kg and Cd/Querc 50mg/kg. Results demonstrated that Cd impaired memory has an anxiogenic effect. Quercetin prevented these harmful effects induced by Cd. AChE activity decreased in the cerebral cortex and hippocampus and increased in the hypothalamus of Cd-exposed rats. The Na(+),K(+)-ATPase activity decreased in the cerebral cortex, hippocampus and hypothalamus of Cd-exposed rats. Quercetin prevented these effects in AChE and Na(+),K(+)-ATPase activities. Reactive oxygen species production, thiobarbituric acid reactive substance levels, protein carbonyl content and double-stranded DNA fractions increased in the cerebral cortex, hippocampus and hypothalamus of Cd-exposed rats. Quercetin totally or partially prevents these effects caused by Cd. Total thiols (T-SHs), reduced glutathione (GSH), and reductase glutathione (GR) activities decreased and glutathione S-transferase (GST) activity increased in Cd exposed rats. Co-treatment with quercetin prevented reduction in T-SH, GSH, and GR activities and the rise of GST activity. The present findings show that quercetin prevents alterations in oxidative stress parameters as well as AChE and Na(+),K(+)-ATPase activities, consequently preventing memory impairment and anxiogenic-like behavior displayed by Cd exposure. These results may contribute to a better understanding of the neuroprotective role of quercetin, emphasizing the influence of this flavonoid in the diet for human health, possibly preventing brain injury associated with Cd intoxication.

Biochemical and hematological effects of acute and sub-acute administration to ethyl acetate fraction from the stem bark Scutia buxifolia Reissek in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Scutia buxifolia is a native tree of Southern Brazil, Uruguay, and Argentina, which is popularly known as "coronilha" and it is used as a cardiotonic, antihypertensive and diuretic substance. The aim of this study was to assess the acute and sub-acute toxicity of the ethyl acetate fraction from the stem bark Scutia buxifolia in male and female mice. MATERIALS AND METHODS: The toxicity studies were based on the guidelines of the Organization for Economic Cooperation and Development (OECD-guidelines 423 and 407). In an acute study, a single dose of 2000 mg/kg of Scutia buxifolia was administered orally to male and female mice. Mortality, behavioral changes, and biochemical and hematological parameters were evaluated. In the sub-acute study, Scutia buxifolia was administered orally to male and female mice at doses of 100, 200, and 400mg/kg/day for 28 days. Behavioral changes and biochemical, hematological, and histological analysis were evaluated. RESULTS: The acute administration of Scutia buxifolia did not cause changes in behavior or mortality. Male and female mice presented decreased levels of platelets. Female mice presented decreased levels of leukocytes. On the other hand, in a sub-acute toxicity study, we observed no behavioral changes in male or female mice. Our results demonstrated a reduction in glucose levels in male mice treated to 200 and 400mg/kg of Scutia buxifolia. Aspartate aminotransferase (ASAT) activity was increased by Scutia buxifolia at 400mg/kg in male mice. In relation to the hematological parameters, male mice presented a reduction in hemoglobin (HGB) and hematocrit (HCT) when treated to 400mg/kg of plant fraction. Female mice showed no change in these parameters. Histopathological examination of liver tissue showed slight abnormalities that were consistent with the biochemical variations observed. CONCLUSION: Scutia buxifolia, after acute administration, may be classified as safe (category 5), according to the OECD guide. However, the alterations observed, after sub-acute administration with high doses of ethyl acetate fraction from the stem bark Scutia buxifolia, suggest that repeated administration of this fraction plant can cause adverse hepatic, renal, and hematological effects.

Neuroprotective role of quercetin in locomotor activities and cholinergic neurotransmission in rats experimentally demyelinated with ethidium bromide.

AIM: The purpose of this study was to investigate whether the flavonoid quercetin can prevent alterations in the behavioral tests and of cholinergic neurotransmission in rats submitted to the ethidium bromide (EB) experimental demyelination model during events of demyelination and remyelination. MAIN METHODS: Wistar rats were randomly distributed into four groups (20 animals per group): Control (pontine saline injection and treatment with ethanol), Querc (pontine saline injection and treatment with quercetin), EB (pontine 0.1% EB injection and treatment with ethanol), and EB+Querc (pontine 0.1% EB injection and treatment with quercetin). The groups Querc and Querc+EB were treated once daily with quercetin (50mg/kg) diluted in 25% ethanol solution (1ml/kg) and the animals of the control and EB groups were treated once daily with 25% ethanol solution (1ml/kg). Two stages were observed: phase of demyelination (peak on day 7) and phase of remyelination (peak on day 21 post-injection). Behavioral tests (beam walking, foot fault and inclined plane test), acetylcholinesterase (AChE) activity and lipid peroxidation in pons, cerebellum, hippocampus, hypothalamus, striatum and cerebral cortex were measured. KEY FINDINGS: The quercetin promoted earlier locomotor recovery, suggesting that there was demyelination prevention or further remyelination velocity as well as it was able to prevent the inhibition of AChE activity and the increase of lipidic peroxidation, suggesting that this compound can protect cholinergic neurotransmission. SIGNIFICANCE: These results may contribute to a better understanding of the neuroprotective role of quercetin and the importance of an antioxidant diet in humans to provide benefits in neurodegenerative diseases such as MS.

Alterations in the extracellular catabolism of nucleotides and platelet aggregation induced by high-fat diet in rats: effects of α-tocopherol.

The aim of this study was to assess whether α-tocopherol administration prevented alterations in the ectonucleotidase activities and platelet aggregation induced by high-fat diet in rats. Thus, we examined four groups of male rats which received standard diet, high-fat diet (HFD), α-tocopherol (α-Toc), and high-fat diet plus α-tocopherol. HFD was administered ad libitum and α-Toc by gavage using a dose of 50 mg/kg. After 3 months of treatment, animals were submitted to euthanasia, and blood samples were collected for biochemical assays. Results demonstrate that NTPDase, ectonucleotide pyrophosphatase/phosphodiesterase, and 5'-nucleotidase activities were significantly decreased in platelets of HFD group, while that adenosine deaminase (ADA) activity was significantly increased in this group in comparison to the other groups (P < 0.05). When rats that received HFD were treated with α-Toc, the activities of these enzymes were similar to the control, but ADA activity was significantly increased in relation to the control and α-Toc group (P < 0.05). HFD group showed an increased in platelet aggregation in comparison to the other groups, and treatment with α-Toc significantly reduced platelet aggregation in this group. These findings demonstrated that HFD alters platelet aggregation and purinergic signaling in the platelets and that treatment with α-Toc was capable of modulating the adenine nucleotide hydrolysis in this experimental condition.

Anthocyanins restore behavioral and biochemical changes caused by streptozotocin-induced sporadic dementia of Alzheimer's type.

AIMS: The aim of this study was to analyze if the pre-administration of anthocyanin on memory and anxiety prevented the effects caused by intracerebroventricular streptozotocin (icv-STZ) administration-induced sporadic dementia of Alzheimer's type (SDAT) in rats. Moreover, we evaluated whether the levels of nitrite/nitrate (NOx), Na(+),K(+)-ATPase, Ca(2+)-ATPase and acethylcholinesterase (AChE) activities in the cerebral cortex (CC) and hippocampus (HC) are altered in this experimental SDAT. MAIN METHODS: Male Wistar rats were divided in 4 different groups: control (CTRL), anthocyanin (ANT), streptozotocin (STZ) and streptozotocin+anthocyanin (STZ+ANT). After seven days of treatment with ANT (200mg/kg; oral), the rats were icv-STZ injected (3mg/kg), and four days later the behavior parameters were performed and the animals submitted to euthanasia. KEY FINDINGS: A memory deficit was found in the STZ group, but ANT treatment showed that it prevents this impairment of memory (P<0.05). Our results showed a higher anxiety in the icv-STZ group, but treatment with ANT showed a per se effect and prevented the anxiogenic behavior induced by STZ. Our results reveal that the ANT treatment (100µM) tested displaces the specific binding of [(3)H] flunitrazepam to the benzodiazepinic site of GABAA receptors. AChE, Ca(+)-ATPase activities and NOx levels were found to be increased in HC and CC in the STZ group, which was attenuated by ANT (P<0.05). STZ decreased Na(+),K(+)-ATPase activity and ANT was able to prevent these effects (P<0.05). SIGNIFICANCE: In conclusion, these findings demonstrated that ANT is able to regulate ion pump activity and cholinergic neurotransmission, as well as being able to enhance memory and act as an anxiolytic compound in animals with SDAT.

Oxidative stress parameters in blood, liver, and kidney of diabetic rats treated with curcumin and/or insulin.

This study evaluated the effects of curcumin and/or insulin on antioxidant enzyme activity in blood, liver, and kidney, as well as on lipid peroxidation and delta aminolevulinic dehydratase (δ-ALA-D) activity, and a histopathological analysis of streptozotocin-induced diabetic rats. The animals were divided into six groups (n = 6): control/saline (C); control/curcumin (CCur); diabetic/saline (D); diabetic/insulin (DIns); diabetic/curcumin (DCur); and diabetic/insulin/curcumin (DInsCur). After 30 days of treatment with curcumin and/or insulin, the animals were sacrificed and the liver, kidney, and serum were used for experimental determinations. Results of histopathological analysis showed that the treatment with insulin ameliorate renal and hepatic lesions from both DIns and DInsCur groups. TBARS levels were significantly increased in serum, liver, and kidney in D group and the administration of curcumin and insulin prevented this increase in DIns and DCur groups. The activities of catalase (CAT), superoxide dismutase, and δ-ALA-D presented a significant decrease in the liver and kidney D group when compared to C group (P < 0.05). The animals treated with curcumin and insulin presented an increase of CAT activity, revealing a positive interaction between both substances. The treatments with curcumin or insulin prevented oxidative stress in blood, through modulation of enzymatic antioxidant defenses. These findings contributed to the comprehension that antioxidants from medicinal plants could be used as adjuvant in the treatment of this endocrinopathy and not as single therapy.

Neuroprotective effect of anthocyanins on acetylcholinesterase activity and attenuation of scopolamine-induced amnesia in rats.

Anthocyanins are a group of natural phenolic compounds responsible for the color to plants and fruits. These compounds might have beneficial effects on memory and have antioxidant properties. In the present study we have investigated the therapeutic efficacy of anthocyanins in an animal model of cognitive deficits, associated to Alzheimer's disease, induced by scopolamine. We evaluated whether anthocyanins protect the effects caused by SCO on nitrite/nitrate (NOx) levels and Na(+),K(+)-ATPase and Ca(2+)-ATPase and acetylcholinesterase (AChE) activities in the cerebral cortex and hippocampus (of rats. We used 4 different groups of animals: control (CTRL), anthocyanins treated (ANT), scopolamine-challenged (SCO), and scopolamine+anthocyanins (SCO+ANT). After seven days of treatment with ANT (200mgkg(-1); oral), the animals were SCO injected (1mgkg(-1); IP) and were performed the behavior tests, and submitted to euthanasia. A memory deficit was found in SCO group, but ANT treatment prevented this impairment of memory (P<0.05). The ANT treatment per se had an anxiolytic effect. AChE activity was increased in both in cortex and hippocampus of SCO group, this effect was significantly attenuated by ANT (P<0.05). SCO decreased Na(+),K(+)-ATPase and Ca(2+)-ATPase activities in hippocampus, and ANT was able to significantly (P<0.05) prevent these effects. No significant alteration was found on NOx levels among the groups. In conclusion, the ANT is able to regulate cholinergic neurotransmission and restore the Na(+),K(+)-ATPase and Ca(2+)-ATPase activities, and also prevented memory deficits caused by scopolamine administration.

Trypanosoma evansi infection impairs memory, increases anxiety behaviour and alters neurochemical parameters in rats.

The aim of this study was to investigate neurochemical and enzymatic changes in rats infected with Trypanosoma evansi, and their interference in the cognitive parameters. Behavioural assessment (assessment of cognitive performance), evaluation of cerebral L-[3H]glutamate uptake, acetylcholinesterase (AChE) activity and Ca+2 and Na+, K+-ATPase activity were evaluated at 5 and 30 days post infection (dpi). This study demonstrates a cognitive impairment in rats infected with T. evansi. At 5 dpi memory deficit was demonstrated by an inhibitory avoidance test. With the chronicity of the disease (30 dpi) animals showed anxiety symptoms. It is possible the inhibition of cerebral Na+, K+-ATPase activity, AChE and synaptosomal glutamate uptake are involved in cognitive impairment in infected rats by T. evansi. The understanding of cerebral host­parasite relationship may shed some light on the cryptic symptoms of animals and possibly human infection where patients often present with other central nervous system (CNS) disorders.

Adenosine levels in serum and adenosine deaminase activity in blood cells of dogs infected by Rangelia vitalii.

Ecto-adenosinedeaminase (E-ADA) plays an important role in the production and differentiation of blood cells as well as in the control of extracellular adenosine levels. Infectious diseases can influence the synthesis of new cells or cause cell destruction, as occurs in canine rangeliosis, which results in anemia, thrombocytopenia, leukocytosis, and/or leukopenia. Thus, this study aimed to evaluate E-ADA activity in sera, erythrocytes, lymphocytes, and adenosine levels in sera samples of dogs infected by Rangelia vitalii. Twelve animals were divided into 2 groups: noninfected (n = 5) and infected by R. vitalii (n = 7). Animals were infected with 2 ml of blood containing the parasite, and parasitemia was estimated daily for 20 days by microscopic examination of peripheral blood smears. Blood collection was performed on days 0, 10, and 20 post-infection (PI) in order to evaluate the evolution of the disease. The blood collected was used to assess the activity of E-ADA. We observed an increase of E-ADA activity in sera (day 20 PI) and erythrocytes (days 10 and 20 PI) in the infected group (P < 0.05). E-ADA activity in lymphocytes was decreased on day 10, when the parasitemia was high, and increased after 20 days, when the number of circulating parasites was low. HPLC measured adenosine levels in the serum and found a reduction on days 10 and 20 PI. In conclusion, our results showed that E-ADA activity was altered in sera, lymphocytes, and erythrocytes of dogs experimentally infected by R. vitalii as well as the serum concentration of adenosine. These alterations may contribute to the pathogenesis of anemia and immune response in infected dogs.

Hematologic and bone marrow changes in dogs experimentally infected with Rangelia vitalii.

BACKGROUND: Rangelia vitalii is a tick-transmitted piroplasm that causes both hemolytic and hemorrhagic disease in dogs in Brazil. OBJECTIVE: The aim of this study was to evaluate the response of the bone marrow in dogs experimentally infected with R vitalii during the acute stage of the disease. METHODS: For this study, 2 groups of a total of 12 young dogs were used. Group A was composed of healthy dogs (n = 5), and group B consisted of animals infected with R vitalii (n = 7). Blood samples were collected on days 0, 10, 20, and 30 post-inoculation and stored in EDTA tubes for a full hematology profile, including a reticulocyte count. On days 10 and 20, bone marrow samples were collected, stained, and examined. RESULTS: In infected dogs anemia was identified on days 10 and 20 post-inoculation (P < .01), and on day 20 reticulocytosis was present. Infected dogs had leukopenia due to neutropenia and eosinopenia, along with lymphocytosis and monocytosis, when compared with control animals. In bone marrow, the myeloid:erythroid ratio was significantly decreased (P < .05) in infected dogs due to increased erythroid precursors. CONCLUSIONS: Dogs experimentally infected with R vitalii develop regenerative extravascular hemolytic anemia accompanied by erythroid hyperplasia in the bone marrow. During the acute phase of the disease, leukopenia due to neutropenia and eosinopenia suggests intense tissue recruitment of these cells in response to the endothelial damage caused by this parasite.

Pre-treatment with curcumin modulates acetylcholinesterase activity and proinflammatory cytokines in rats infected with Trypanosoma evansi.

The potent activity against Trypanosomes and health beneficial effects of curcumin (Cur) has been demonstrated in various experimental models. In this study, we evaluated the in vivo effect of Cur as trypanocide and as potential anti-inflammatory agent, through the evaluation of immunomodulatory mechanisms in rats infected with Trypanosoma evansi. Daily oral Cur was administered at doses of 0, 20 or 60mg/kg as preventive treatment (30 and 15days pre infection) and as treatment (post infection). The treatment of the groups continued until the day of euthanasia. Fifteen days after inoculation, parasitemia, plasma proinflammatory cytokines (IFN-γ, TNF-α, IL-1, IL-6), anti-inflammatory cytokines (IL-10) and blood acetylcholinesterase activity (AChE) were analyzed. Pretreatment with Cur reduced parasitemia and lethality. Cur inhibited AChE activity and improved immunological response by cytokines proinflammatory, fundamental during T. evansi infection. We found that Cur is not so important as an antitrypanosomal activity but as immunomodulator agent. These findings reveal that the preventive use of Cur stimulates anti-inflammatory mechanisms, reducing an excessive inflammatory response.

NTPDase and 5'-nucleotidase activities from synaptosomes and platelets of rats exposed to cadmium and treated with N-acetylcysteine.

The purpose of the present investigation was to evaluate the hydrolysis of adenine nucleotides on synaptosomes and platelets obtained from rats exposed to cadmium (Cd) and treated with N-acetylcysteine (NAC). Rats received Cd (2 mg/kg) and NAC (150 mg/kg) by gavage every other day for 30 days. Animals were divided into four groups (n = 4-6): control/saline, NAC, Cd, and Cd/NAC. The results of this study demonstrated that NTPDase and 5'-nucleotidase activities were increased in the cerebral cortex synaptosomes of Cd-poisoned rats, and NAC co-treatment reversed these activities to the control levels. In relation to hippocampus synaptosomes, no differences on the NTPDase and 5'-nucleotidase activities of Cd-poisoned rats were observed and only the 5'-nucleotidase activity was increased by the administration of NAC per se. In platelets, Cd-intoxicated rats showed a decreased NTPDase activity and no difference in the 5'-nucleotidase activity; NAC co-treatment was inefficient in counteracting this undesirable effect. Our findings reveal that adenine nucleotide hydrolysis in synaptosomes and platelets of rats were altered after Cd exposure leading to a compensatory response in the central nervous system and acting as a modulator of the platelet activity. NAC was able to modulate the purinergic system which is interesting since the regulation of these enzymes could have potential therapeutic importance. Thus, our results reinforce the importance of the study of the ecto-nucleotidases pathway in poisoning conditions and highlight the possibility of using antioxidants such as NAC as adjuvant against toxicological conditions.

Serum proteinogram, acute phase proteins and immunoglobulins in dogs experimentally infected with Rangelia vitalii.

The present study aimed to evaluate the serum proteinogram, acute phase proteins (APPs) and immunoglobulins (Igs) of dogs experimentally infected by Rangelia vitalii in the acute phases of the disease. Banked serum samples collected on days 0, 10 and 20 during a previously reported R. vitalii experimental infection were used to analyze the serum proteinogram, APPs (C-reactive protein - CRP and alpha-1-acid glycoprotein - AGP) and Igs (IgM, IgG, IgA and IgE) in the current study. Total protein and albumin level were significantly (P<0.05) decreased at day 10 PI and 20 PI in infected sera compared to the control sera. Alpha-1 globulin (day 10 PI) and gamma globulin (day 20 PI) were increased (P<0.01) in infected sera. Alpha-2 globulin (days 10 and 20 PI) and beta-2 globulin (day 10 PI) were decreased (P<0.05) in infected sera compared to control sera. Beta-1 globulin fraction did not differ statistically between sera. Serum CRP and AGP concentrations were significantly increased (P<0.05) at days 10 and 20 PI in infected sera. IgG was increased at days 10 (P<0.05) and 20 PI (P<0.01) in infected sera. Furthermore, it was also observed an increase (P<0.01) in the levels of IgM, IgA, and IgE in infected sera than control sera. We conclude that R. vitalii infection causes alterations in the proteinogram, and increases in the levels of APPs and Igs. Further studies are essentials to define the causes of these pathological changes in this disease.

Protective effects of anthocyanins on the ectonucleotidase activity in the impairment of memory induced by scopolamine in adult rats.

AIMS: We investigated whether the treatment with anthocyanins prevents the scopolamine-induced memory deficits and whether ectonucleotidase activities and purine levels are altered in the cerebral cortex (CC) and hippocampus (HC) in this model of mnemonic deficit in rats. MAIN METHODS: The animals were divided into 4 experimental groups: control (vehicle), anthocyanins (Antho), scopolamine (SCO), and scopolamine plus anthocyanins (SCO+Antho). After seven days of treatment, they were tested in the inhibitory avoidance task and open field test and submitted to euthanasia. The CC and the HC were collected for biochemical assays. The effect of treatment with Antho (200 mgkg(-1), i.p.) was investigated in rats trained to a stable level of performance and post-treated with SCO (1 mgkg(-1), i.p. 30 min after training). KEY FINDINGS: The treatment with SCO decreased the step-down latency in inhibitory avoidance task. Antho prevented the scopolamine-induced memory impairment and also the increase of NTPDase activity in the CC and HC. Furthermore, the treatment with anthocyanins prevents the decrease in 5'-nucleotidase activity and the increase in adenosine deaminase activity induced by SCO in HC. In addition, the treatment with Antho prevented the decrease in ATP levels induced by SCO in the CC and HC. SIGNIFICANCE: Our results show that scopolamine may affect purinergic enzymatic cascade or cause alterations in energy metabolism inducing loss of memory. In contrast Antho could reverse these changes, suggesting a neuroprotective effect of Antho on ectonucleotidase activities and neuronal energetic metabolism.

Cholinesterase as inflammatory markers in a experimental infection by Trypanosoma evansi in rabbits.

The aim of this study is to evaluate the role of cholinesterases as an inflammatory marker in acute and chronic infection by Trypanosoma evansi in rabbits experimentally infected. Twelve adult female New Zealand rabbits were used and divided into two groups with 6 animals each: control group (rabbits 1-6) and infected group (rabbits 7-12). Infected group received intraperitoneally 0.5 mL of blood from a rat containing 108 parasites per animal. Blood samples used for cholinesterases evaluation were collected on days 0, 2, 7, 12, 27, 42, 57, 87, 102 and 118 days post-inoculation (PI). Increased activity (P<0.05) of butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) were observed in the blood on days 7 and 27, respectively and no differences were observed in cholinesterase activity in other periods. No significant difference in AChE activity (P>0.05) was observed in the encephalic structures. The increased activities of AChE and BChE probably have a pro-inflammatory purpose, attempting to reduce the concentration of acetylcholine, a neurotransmitter which has an anti-inflammatory property. Therefore, cholinesterase may be inflammatory markers in infection with T. evansi in rabbits.

Hematological indices and activity of NTPDase and cholinesterase enzymes in rats exposed to cadmium and treated with N-acetylcysteine.

The present study aimed to investigate the influence of N-acetylcysteine (NAC) on cadmium (Cd) poisoning by evaluating Cd concentration in tissues, hematological indices as well as the activity of NTPDase, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes of rats exposed to Cd and co-treated with NAC. For this purpose, the rats received Cd (2 mg/kg) and NAC (150 mg/kg) by gavage every other day for 30 days. Animals were divided into four groups (n = 6-8): control/saline, NAC, Cd, and Cd/NAC. Cd exposure increased Cd concentration in plasma, spleen and thymus, and NAC co-treatment modulated this augment in both lymphoid organs. Cd exposure reduced red blood cell count, hemoglobin content and hematocrit value. Cd intoxication caused a decrease in total white blood cell count. NAC treatment per se caused an increase in lymphocyte and a decrease in neutrophil counts. On contrary, Cd exposure caused a decrease in lymphocyte and an increase in neutrophil and monocyte counts. NAC reversed or ameliorated the hematological impairments caused by Cd poisoning. There were no significant alterations in the NTPDase activity in lymphocytes of rats treated with Cd and/or NAC. Cd caused a decrease in the activities of lymphocyte AChE, whole blood AChE and serum BChE. However, NAC co-treatment was inefficient in counteracting the negative effect of Cd in the cholinesterase activities. The present investigation provides ex vivo evidence supporting the hypothesis that Cd induces immunotoxicity by interacting with the lymphoid organs, altering hematological parameters and inhibiting peripheral cholinesterase activity. Also, it highlights the possibility to use NAC as adjuvant against toxicological conditions.

Biochemistry detection of acetylcholinesterase activity in Trypanosoma evansi and possible functional correlations.

Several chemical and immunohistochemical techniques can be used for the detection of acetylcholinesterase (AChE) activity. In this experiment we aimed to detect AChE activity in Trypanosoma evansi. For this, the parasites were isolated from the blood of experimentally infected rats using a DEA-cellulose column. Enzymatic activity was determined in trypomastigote forms at 0, 0.2, 0.4, 0.8 and 1.2 mg/mL of protein concentrations by a standard biochemical protocol. At all concentrations tested, the study showed that T. evansi expresses the enzyme AChE and its activity was proportional to the concentration of protein, ranging between 0.64 and 2.70 µmol of AcSCh/h. Therefore, we concluded that it is possible to biochemically detect AChE in T. evansi, an enzyme that may be associated with vital functions of the parasite and also can be related to chemotherapy treatments, as further discussed in this article.

Complete blood count and acetylcholinesterase activity of lymphocytes of demyelinated and ovariectomized rats treated with resveratrol.

Resveratrol is a phytoestrogen that has many beneficial actions. This study aimed to evaluate the effect of resveratrol on the complete blood count (CBC) and the acetylcholinesterase (AChE) activity of lymphocytes of ovariectomized rats experimentally demyelinated by ethidium bromide (EB). Forty adult female Wistar rats (60 days, 200-220 g) were divided randomly into five groups (n = 4) to evaluate the demyelination phase and five groups (n = 4) to evaluate the remyelination phase. In each phase, the groups consisted of sham rats-G1; ovariectomized rats, not demyelinated, treated only with vehicle (ethanol 25%)-G2; demyelinated ovariectomized rats treated only with vehicle-G3; ovariectomized rats, not demyelinated, treated with resveratrol-G4; and demyelinated ovariectomized rats treated with resveratrol-G5. Only during the remyelination phase, CBC showed a significant difference (p < 0.05) in the number of monocytes between G2 and G5 groups. In the demyelination phase, there was a significant decrease (p < 0.05) in the AChE activity in the G4 group, while the G5 group was statistically similar to the G1, G2 and G4 groups. In the remyelination phase, there were no significant differences in the AChE activity among the groups. The treatment for 7 days with resveratrol with or without the experimental demyelization with EB appears to influence the AChE activity of lymphocytes, without changing the number of these cells in the circulation. However, in the remyelination phase, there seems to be stabilization in its effect on the lymphocyte AChE activity.

Activities of ectonucleotidases and adenosine deaminase in platelets of dogs experimentally infected with Rangelia vitalii.

Rangeliosis is a disease which affects dogs in Brazil, caused by a piroplasm known as Rangelia vitalii. This disease causes a lot of clinico-pathological features, including the coagulation disorders associated with bleeding. The cause of these changes has not yet been determined. Considering the association of purinergic system and hemostasis this study aimed to evaluate the activity of enzymes that hydrolyze ATP, ADP and AMP; and deamination of adenosine in platelets from dogs experimentally infected with R. vitalii. For this study, 12 healthy young dogs (females) were used, separated in two groups. Group A (n=5) were uninfected controls, and group B were experimentally infected with R. vitalii (n=7). After being inoculated with R. vitalii-infected blood, animals were monitored by blood smear examinations, which showed intra-erythrocytic forms of the parasite after five days post-inoculation (PI). Blood samples were collected to quantitate and separate platelets (Day 0, 12 and 21 PI) and to measure the enzymatic activities (Day 12 and 21 PI). The activity of NTPDase, 5'-nucleotidase and adenosine deaminase (ADA) was measured in platelets. A reduction (P<0.01) in the number of platelets was observed in R. vitalii-infected blood at Days 12 and 21 PI. At Day 12 PI, a reduction (P<0.01) in the hydrolysis of ATP, ADP and AMP, and deamination of adenosine was observed in dogs infected with R. vitalii. At Day 21 PI the ADA activity remained decreased, unlike the activity of NTPDase which increased (P<0.05). Based on these results we can conclude that ATP, ADP and AMP hydrolysis and adenosine deamination were altered in platelets of R. vitalii-infected dogs. Considering the importance of the purinergic system in hemostasis, it is believed that those changes contribute to the coagulation disorders and bleeding observed in R. vitalii-infected dogs and discussed in this manuscript.