Effects of clopidogrel bisulfate on B16-F10 cells and tumor development in a murine model of melanoma.

Metastatic melanoma is a very aggressive skin cancer. Platelets are constituents of the tumor microenvironment and, when activated, contribute to cancer progression, especially metastasis and inflammation. P2Y12 is an adenosine diphosphate receptor that triggers platelet activation. Inhibition of P2Y12 by clopidogrel bisulfate (CB) decreases platelet activation, which is also controlled by the extracellular concentration and the metabolism of purines by purinergic enzymes. We evaluated the effects of CB on the viability and proliferation of cultured B16-F10 cells. We also used a metastatic melanoma model with C57BL-6 mice to evaluate cancer development and purine metabolism modulation in platelets. B16-F10 cells were administered intraperitoneally to the mice. Two days later, the animals underwent a 12-day treatment with CB (30 mg/kg by gavage). We have found that CB reduced cell viability and proliferation in B16-F10 culture in 72 h at concentrations above 30 µm. In vivo, CB decreased tumor nodule counts and lactate dehydrogenase levels and increased platelet purine metabolism. Our results showed that CB has significant effects on melanoma progression.

Effect of Thiazolidin-4-one Against Lipopolysaccharide-Induced Oxidative Damage, and Alterations in Adenine Nucleotide Hydrolysis and Acetylcholinesterase Activity in Cultured Astrocytes.

Astrocytes play multiple important roles in brain physiology. However, depending on the stimuli, astrocytes may exacerbate inflammatory reactions, contributing to the development and progression of neurological diseases. Therefore, therapies targeting astrocytes represent a promising area for the development of new brain drugs. Thiazolidinones are heterocyclic compounds that have a sulfur and nitrogen atom and a carbonyl group in the ring and represent a class of compounds of great scientific interest due to their pharmacological properties. The aim of this study was to investigate the effect of 3-(3-(diethylamino)propyl)-2-(4-(methylthio)phenyl)thiazolidin-4-one (DS27) on cell proliferation and morphology, oxidative stress parameters, activity of the enzymes ectonucleotidases and acetylcholinesterase (AChE) and interleukin 6 (IL-6) levels in primary astrocyte cultures treated with lipopolysaccharide (LPS), to model neuroinflammation. The astrocyte culture was exposed to LPS (10 µg/ml) for 3 h and subsequently treated with compound DS27 for 24 and 48 h (concentrations ranging to 10-100 µM). LPS induced an increase in astrocyte proliferation, AChE activity, IL-6 levels, oxidative damage, ATP and ADP and a reduction in AMP hydrolysis in rat primary astrocyte cultures. DS27 treatment was effective in reversing these alterations induced by LPS. Our findings demonstrated that DS27 is able to modulate cholinergic and purinergic signaling, redox status, and the levels of pro-inflammatory cytokines in LPS-induced astrocyte damage. These glioprotective effects of DS27 may be very important for improving neuroinflammation, which is associated with many brain diseases.

Detection of anti-Sarcocystis spp. antibodies in domestic cats, in southern Brazil.

Parasites of the genus Sarcocystis can infect several species of animals and cause multiple diseases such as equine protozoal myeloencephalitis. Felines are considered hosts of this protozoa; therefore, the present study aimed to detect anti-Sarcocystis spp.-specific antibodies in domestic cats that were under clinical evaluation, using the indirect immunofluorescence antibody test. Anti-Sarcocystis-specific immunoglobulin Gs were detected in 24 out of 497 (4.82%) cat serum samples. These findings support the fact that natural Sarcocystis infections do occur in cats. Furthermore, it highlights the importance of domestic cats as both intermediate and definitive hosts in the Sarcocystis life cycle, maintaining the parasite and serving as a source of infection for various other animals. To the best of our knowledge, this is the first study to identify antibodies against the genus Sarcocystis in cats from a region in southern Brazil.

Increased seroprevalence of anti-Toxoplasma gondii antibodies in dogs in southern Brazil after an outbreak of human toxoplasmosis.

Toxoplasmosis is a worldwide disease caused by Toxoplasma gondii, which can infect diverse hosts, including dogs. Although T. gondii infection in dogs is usually subclinical, they are susceptible to infection and develop a specific immune response to the parasite. In 2018, the largest outbreak of human toxoplasmosis in the world occurred in Santa Maria, in southern Brazil; however, the impact of this outbreak on other hosts was not investigated at the time. Considering that dogs often share the same environmental sources of infection as humans, mainly water sources, and that in Brazil, the detection rates of anti-T. gondii immunoglobulin G (IgG) in dogs is very high, this study investigated the frequency of anti-T. gondii IgG in dogs in Santa Maria before and after the outbreak. A total of 2.245 serum samples were analyzed, 1159 collected before the outbreak and 1086 collected after the outbreak. Serum samples were tested for anti-T. gondii antibodies using an indirect immunofluorescence antibody test (IFAT). The infection detection of T. gondii was 16% (185/1159) before the outbreak and 43% (466/1086) after the outbreak. These results showed the infection of dogs with T. gondii and the high frequency of anti-T. gondii antibodies in dogs after the outbreak in humans in 2018, reinforcing water as a possible source of infection and the importance of including toxoplasmosis in the differential diagnosis of dogs.

Curcumin modulates neurogliogenesis and purinergic receptor expression in neural precursor cells infected with Toxoplasma gondii.

Toxoplasma gondii is an obligate intracellular parasite that causes toxoplasmosis, and its congenital transmission is of paramount concern. During embryonic development, infection with the parasite causes irreversible damage to the still-forming fetus's central nervous system (CNS). In the pathogenesis of neurotoxoplasmosis, purinergic receptors prejudice neuroprotection, neuroinflammation, and activation of microbicide mechanisms against the parasitic vacuole. This study used curcumin as a treatment for neural precursor cells (NPCs) infected with T. gondii. The congenital toxoplasmosis induction consisted of maternal infection with the VEG strain, and NPCs were obtained from the telencephalon of mouse embryos. Curcumin at increasing concentrations was administered in vitro to analyze NPC metabolic activity, cell number, and size, as well as neurogliogenesis, proving to be effective in recovering the size of infected NPCs. Curcumin partially re-established impaired neurogenesis. Purinergic A1, A2A, and P2X7 receptors may be related to neuroprotection, neuroinflammatory control, and activation of mechanisms for inducing the parasite's death. ERK 1/2 was highly expressed in infected cells, while its expression rates decreased after the addition of the treatment, highlighting the possible anti-inflammatory action of curcumin. These findings suggest that curcumin treats neurological perturbations induced by toxoplasmosis.

Increased frequency of detection of anti-Toxoplasma gondii antibodies in domestic cats after outbreak of human toxoplasmosis.

Toxoplasmosis affects various organisms, including humans. In 2018, the largest outbreak of human toxoplasmosis described so far was reported in southern Brazil, with 809 human cases reported, and water as the potentially primary source of infection. Therefore, in this study, we aimed to evaluate the seroprevalence of Toxoplasma gondii in naturally infected domestic cats before and after the human toxoplasmosis outbreak, as well as the potential for environmental contamination by the number of cats infected after the outbreak. We evaluated 381 serum samples from domestic cats in southern Brazil, using an indirect immunofluorescence assay, with samples considered positive at a titer of 1:20. We found that 73% (204/279) and 27% (75/279) of the samples analyzed before the outbreak were negative and positive, respectively. After the outbreak, 62% (69/112) were negative of the samples were and 38% (43/112) were positive. Notably, the proportion of positive samples before the outbreak before (27%) was significantly lower than that after the outbreak (38%; P = 0.020). Therefore, the increased seroprevalence of T. gondii in cats was probably correlated with the ingestion of contaminated water. Therefore, it is important to monitor animals, mainly definitive hosts, after toxoplasmosis outbreaks, considering that these animals can contaminate the environment and, consequently, humans.

Modulation of Inflammatory Mediators and Microglial Activation Through Physical Exercise in Alzheimer's and Parkinson's Diseases.

Neuroinflammation is an inflammatory process in the central nervous system (CNS), in addition to being one of the main features of Alzheimer's disease (AD) and Parkinson's disease (PD). Microglia are known for their immune functions and have multiple reactive phenotypes related to the types of stages involving neurodegenerative diseases. Depending on the state of activation of microglia in the CNS, it can be neuroprotective or neurotoxic. In this context, AD is a neurodegenerative and neuroinflammatory disease characterized by the deposition of beta-amyloid plaques, formation of fibrillar tangles of tau protein, and loss of neurons due to neurotoxic activation of microglia. However, PD is characterized by the loss of dopaminergic neurons in the substantia nigra and accumulation of alpha-synuclein in the cortical regions, spinal cord, and brain stem, which occurs by microglial activation, contributing to the neuroinflammatory process. In this aspect, the activation of microglia in both pathologies triggers high levels of inflammatory markers, such as interleukins, and causes the neuroinflammatory process of the diseases. Thus, physical exercise is pointed out as neuroprotective, as it can act to strengthen neurogenesis and reduce the inflammatory process. Therefore, the present review addresses the neuroprotective effect of microglia after different types of physical exercise protocols and evaluates the activity and effects of inflammatory and anti-inflammatory parameters and mechanisms of AD and PD. This review will discuss the anti-inflammatory effects of physical exercise through microglia activation with neuroprotective activity and the role of pro-and anti-inflammatory cytokines in AD and PD.

Berberine increases the expression of cytokines and proteins linked to apoptosis in human melanoma cells.

BACKGROUND: Melanoma is the most lethal form of skin cancer, and its incidence has increased considerably in the last decades. Melanoma presents difficult treatment with strong resistance of tumor cells, due to its extremely invasive nature with high capacity to metastases. Berberine (BBR), an isoquinoline alkaloid, is a molecule found in several medicinal plants, and has been studied in several diseases, demonstrating antimicrobial, antidiabetic and anti-inflammatory properties and anti-tumorigenic effects. METHODS AND RESULTS: In SK-MEL-28 cells, 50 µM BBR treatment for 24 h decreased cell viability by 50 percent. This concentration generated cell death both by early apoptosis and necrosis, with an increase in the DNA damage index. BBR increased (*p < 0.05) the proportion of cells in G1/G0 phase and decreased (###p < 0.005) the percentage of cells in S phase. The alcaloid increased (****p < 0.001) ROS production compared to untreated controls with an increase in activated caspase 3 and phosphorylated p53 protein levels. In addition, BBR significantly enhanced ERK as well as both pro- and anti-inflammatory cytokine expression compared to untreated controls. CONCLUSIONS: BBR has important antiproliferative effects and may be alone or in adjunct therapy a promising candidate for melanoma treatment, a cancer with great incidence and high lethality.

Safety and efficacy of Lucilia cuprina maggots on treating an induced infected wound in Wistar rats.

Infection is one of the main complications that hinder wound healing. Currently, antibiotic-resistant bacteria, such as Methicilin-resistant Staphylococcus aureus (MRSA), are a concern worldwide for both humans and animals. Maggot therapy is re-emerging as an alternative to intractable wounds and may be an option to the traditional antibiotic treatment. Although the species of choice is Lucilia sericata, reports of clinical use have led us to evaluate the efficacy and safety of using Lucilia cuprina larvae on induced infected wounds in Wistar rats. In short, 32 male Wistar rats were divided into 4 groups: Group I - saline solution treated; Group II - antibiotic-treated; Group III - treated with larval debridement, and Group IV - without wound and treatment. Skin wounds were induced in groups I, II and III. All treatments were performed once and held for 48 h. Clinical, microbiological, histopathological, hematological, and biochemical analyses were done. Significant wound area contraction was found (>95%) in group III on day 9 compared to day 15 in group II. Complete elimination (0.0 ± 0.0 CFU/mL) of bioburden was achieved after the second treatment (day 6) in both the II and III groups, compared to an increase in Group I (6.51 ± 0.37 CFU/mL). A cleaner wound was also observed in the histopathological evaluation of group III, with adequate collagen formation and re-epithelialization on day 15. Furthermore, larvae increased blood platelet levels after the first treatment. L. cuprina larvae have proven safe and effective in accelerating wound treatment and eliminating MRSA.

Dynamics of Leishmania spp. infection in dogs from an unaffected region in transition to a visceral leishmaniasis transmission area, Rio Grande do Sul, Brazil.

In Brazil, visceral leishmaniasis (VL) has been expanding and urbanizing, mainly in non-endemic areas such as the State of Rio Grande do Sul. Considering that infected dogs are the main reservoirs of VL in urban areas, the present study aimed to evaluate the propagation of canine visceral leishmaniasis (CVL) infection from an unaffected region in transition to a VL transmission area. For this, 1159 and 1087 samples of canine serum from 2015 and 2021, respectively, were analyzed, using the indirect immunofluorescence test. In addition, necropsy reports between 2007 and 2021 were evaluated. The results showed a prevalence of anti-Leishmania spp. antibodies of 7.5% in the samples from 2015, while in 2021 samples, it was 23.5%, with an incidence of 0.4 cases per 100 dogs. It is noteworthy that in 2007, there was no record of CVL as the cause of death in the pathological reports, and in 2021, 41 diagnoses were made with the protozoan being a determinant of the death of the animal. These values indicate an increasing trend in the prevalence and incidence coefficients of CVL. The results of this study allowed us to verify the spread of the disease from an unaffected region to a transmission area of the agent, as well as provide subsidies for health authorities to implement improvements in the CVL control program in the municipality, to mitigate the emergence of human cases of the disease.

Multitarget Effect of 2-(4-(Methylthio)phenyl)-3-(3-(piperidin-1-yl)propyl)thiazolidin-4-one in a Scopolamine-Induced Amnesic Rat Model.

Cholinergic system dysfunction, oxidative damage, and alterations in ion pump activity have been associated with memory loss and cognitive deficits in Alzheimer's disease. 1,3-thiazolidin-4-ones have emerged as a class of compounds with potential therapeutic effects due to their potent anticholinesterase activity. Accordingly, this study investigated the effect of the 2-(4-(methylthio)phenyl)-3-(3-(piperidin-1-yl)propyl)thiazolidin-4-one (DS12) compound on memory, cholinergic and oxidative stress parameters, ion pump activity, and serum biochemical markers in a scopolamine-induced memory deficit model. Male Wistar rats were divided into four groups: I-Control; II-Scopolamine; III-DS12 (5 mg/kg) + scopolamine; and IV-DS12 (10 mg/kg) + scopolamine. The animals from groups III and IV received DS12 diluted in canola oil and administered for 7 days by gavage. On the last day of treatment, scopolamine (1 mg/kg) was administered intraperitoneally (i.p.) 30 min after training in an inhibitory avoidance apparatus. Twenty-four hours after scopolamine administration, the animals were subjected to an inhibitory avoidance test and were thereafter euthanized. Scopolamine induced memory deficits, increased acetylcholinesterase activity and oxidative damage, and decreased Na+/K+-ATPase activity in cerebral cortex and hippocampus. Pretreatment with DS12 prevented these brain alterations. Scopolamine also induced an increase in acetylcholinesterase activity in lymphocytes and whereas butyrylcholinesterase in serum and treatment with DS12 prevented these changes. In animals treated with DS12, no changes were observed in renal and hepatic parameters when compared to the control group. In conclusion, DS12 emerged as an important multitarget compound capable of preventing neurochemical changes associated with memory deficits.

Moringa oleifera modulates cholinergic and purinergic enzymes activity in BV-2 microglial cells.

Microglia are immune cells that are resident in central nervous system. Activation of microglial cells are detrimental to the survival of neurons. Thus, prevention of microglia activation and/or protection against microglia activation could be potential therapeutic strategy towards the management of inflammation-mediated neurodegenerative diseases. Moringa oleifera is widely consumed as food and used in folklore medicine for treating several diseases. This study was convened to investigate the effect of aqueous extract of Moringa oleifera on cell viability, cholinergic and purinergic enzymes in BV-2 microglial cultured cell. Aqueous extract of Moringa oleifera was prepared, lyophilized and reconstituted in 0.5% dimethylsulphoxide (DMSO). Cells were treated with Moringa oleifera extracts (0.1-100 µg/mL) and assessed for cell viability and nitric oxide production. Furthermore, the effect of Moringa oleifera on enzymes of cholinergic (acetylcholinesterase) and purinergic (nucleoside triphosphate diphosphohydrolase; NTPDase, 5' nucleotidase and adenosine deaminase; ADA) systems in BV-2 microglial cells were determined. Incubation of BV-2 microglia cell with M. oleifera extract maintained cell viability, modulated cholinergic and purinergic enzymes activity. The phenolic compounds found in M. oleifera extracts, include chlorogenic acid, rutin; quercetin pentoside, kaempferol derivative and quercetin derivative. Thus, this study suggest that the potential therapeutic effect of the phenolic compounds found in M. oleifera may have been responsible for the maintenance of cell viability in BV-2 microglia cells and modulation of cholinergic as well as purinergic enzymes activity.

Antioxidant, hepatoprotective, genoprotective, and cytoprotective effects of quercetin in a murine model of arthritis.

Rheumatoid arthritis is a highly debilitating inflammatory autoimmune disease which is characterized by joint destruction. The present study sought to investigate the effect of quercetin in rats with complete Freund's adjuvant-induced arthritis. Animals were divided into control/saline, control/quercetin (5 mg/kg, 25 mg/kg, and 50 mg/kg) arthritis/saline, and arthritis/quercetin (5 mg/kg, 25 mg/kg, and 50 mg/kg); the treatments were administered for 45 days. Biochemical, oxidative stress, genotoxicity, and cytotoxicity parameters were evaluated. All doses of quercetin reduced the levels of aspartate aminotransferase, thiobarbituric acid-reactive substances, and reactive oxygen species; however, only treatment with 25 or 50 mg/kg increased catalase activity. Total thiol and reduced glutathione levels were not significantly affected by the induction nor by the treatments. Genotoxicity assessed by DNA damage, and cytotoxicity through picogreen assay, decreased after treatments with quercetin. Our results present evidence of the antioxidant, cytoprotective, genoprotective and hepatoprotective, and effects of quercetin, demonstrating its potential as a candidate for coadjuvant therapy.

Ellagic Acid Inhibits Neuroinflammation and Cognitive Impairment Induced by Lipopolysaccharides.

Neuroinflammation is a predisposing factor for the development of cognitive impairment and dementia. Among the new molecules that are currently being studied, ellagic acid (EA) has stood out for its neuroprotective properties. The present study investigated the effects of ellagic acid in the object recognition test, oxidative stress, cholinergic neurotransmission, glial cell expression, and phosphorylated Tau protein expression. For this, 32 male Wistar rats received an intraperitoneal (IP) application of lipopolysaccharides (LPS) at a dose of 250 µg/kg or 0.9% saline solution (SAL) for 8 days. Two hours after the IP injections, the animals received 100 mg/kg of EA or SAL via intragastric gavage. Behavioral parameters (open field test and object recognition) were performed on days 5, 6, and 7 of the experimental periods. The results showed that the treatment with EA in the LPS group was able to inhibit cognitive impairment, modulate the immune system response by significantly reducing glial cell expression, attenuating phosphorylated Tau and oxidative damage with consequent improvement in the antioxidant system, as well as preventing the increase of acetylcholinesterase activity. Thus, the neuroprotective effects of EA and its therapeutic potential in cognitive disorders secondary to neuroinflammation were demonstrated.

Berberine induces apoptosis in glioblastoma multiforme U87MG cells via oxidative stress and independent of AMPK activity.

Glioblastoma multiforme (GM) is the most prevalent tumor among gliomas and presents the highest mortality rate among brain tumors. Berberine (BBR) is an alkaloid isoquinoline found in medicinal plants such as Coptis chinensis. Studies have been showed that BBR presents protective activity in mesenchymal cells and neurons, and antitumor properties in breast cancer and hepatocarcinoma. The aim of this study was to investigate the antitumor effects of BBR in GM U87MG cells, as well as to identify, whether such effects are mediated by oxidative stress and canonical apoptotic pathways. After treatment with several concentrations of BBR (10, 25, 100 and 250 µM) for 24, 48 and 72 h of exposure, BBR reduce cell viability of U87MG cells in a concentration- and time-dependent manner. Afterwards, it was observed that BBR, starting at a concentration of 25 µM of 24 h exposure, significantly suppressed proliferation and increased early apoptosis (53.5% ± 11.15 of annexin V+ propidium iodide- cells) compared to untreated cells (7.5% ± 4.6). BBR-induced apoptosis was independent from AMPK activity and did not change total caspase-3 and p-p53 levels. Moreover, BBR (25 µM/24 h) increased oxidative stress in U87MG cells, evidenced by high levels of reactive oxygen species, thiobarbituric acid reactive substance and protein carbonylation. Considering the antitumor effects of BBR in U87MG cells, this compound may be a potential candidate for adjuvant GM treatment.

Hydroalcoholic extract of leaf of Arachis hypogaea L. (Fabaceae) did not induce toxic effects in the repeated-dose toxicity study in rats.

Arachis hypogaea L. (peanut) leaf is traditionally used for the treatment of insomnia in Asia. However, studies describing the safety and toxicity profile for this plant preparation are limited. Thus, the goal of this study was to investigate the toxicity of peanut leaf hydroalcoholic extract (PLHE) repeated treatment. The extract was administered orally (100, 300 or 1000 mg/kg) in male and female Wistar rats for 28 days (OECD guideline 407). PLHE treatment did not cause mortality or weight variation in the animals. Also, there was no alteration on locomotor activity (open field test), motor coordination (rotarod test), or anxiety behaviour (elevated plus-maze test). Male rats had a reduction in relative liver weight (100 mg/kg) and an increase in total kidney weight (1000 mg/kg), but there was no change in biochemical and haematological parameters after PLHE treatment. Free extracellular double-stranded DNA (dsDNA) levels was also evaluated, but PLHE treatment did not increase this parameter in rat organs. Also, the dose of 1000 mg/kg of PLHE significantly increased the total thiols in the liver of females compared with the control animals. Thus, PLHE did not induce toxicity after repeated exposure for 28 days in rats.

Interferon gamma/interleukin-4 modulation, anti-inflammatory and antioxidant effects of hesperidin in complete Freund's adjuvant (CFA)-induced arthritis model of rats.

BACKGROUND: This study sought to assess the effect of hesperidin on serum inflammatory cytokines and oxidative damage in liver of complete Freund's adjuvant (CFA)-induced arthritic rats. METHOD: Fifty-six adult female Wistar rats (220-250 g) were acclimatized for two weeks. Intraplantar injection of CFA was done for the induction of arthritis and confirmed on the 14th day prior to oral administration of 40 and 80 mg/kg of hesperidin or dexamethasone for 45 days. RESULT: The result showed that treatment with both doses of hesperidin and dexamethasone in the joint of arthritic rats significantly (p < .05) diminished paw swelling/edema and arthritis score as well as enhanced latency in thermal hyperalgesia test. In addition, hesperidin treatment in arthritis rats showed significant (p < .01) improvement in red blood cells and platelets counts as well as hemoglobin and hematocrit compared to the arthritis control rat group. Furthermore, hesperidin treatment significantly (p < .05) reduced serum interferon gamma (IFN-γ) and interleukin-4 (IL-4) levels in arthritic rat. In addition, treatment with hesperidin significantly (p < .05) decreased the liver of thiobarbituric acid reactive species and reactive oxygen species levels but raised the levels of total and non-protein thiols of rat induced with CFA. The reduced activities of liver δ-aminolevulinate dehydratase, catalase, glutathione-S transferase in arthritic rats were significantly (p < .05) increased with hesperidin treatment in arthritic rats. This study suggests that hesperidin demonstrated an anti-arthritic effect via modulation of serum IFN-γ and IL-4 levels as well as protection against oxidative damage. CONCLUSION: Hence, hesperidin could be a potential immune-modulatory, anti-inflammatory and anti-oxidant agent.

Antiproliferative and apoptotic effects of caffeic acid on SK-Mel-28 human melanoma cancer cells.

Cutaneous melanoma (CM) is an extremely aggressive cancer presenting low survival and high mortality. The vast majority of patients affected by this disease does not respond or show resistance to the chemotherapeutic drugs, which makes the treatment ineffective. In this sense, the necessity for the development of new agents to assist in CM therapy is extremely important. One of the sources of great interest in this search are compounds of natural origin. Among these compounds, caffeic acid has demonstrated a broad spectrum of pharmacological activities as well as antitumor effects in some types of cancer. Therefore, the objective of this work was to investigate the possible antitumor effect of caffeic acid on the SK-Mel-28 cell line, human CM cells. Cells were cultured in flasks with culture medium containing fetal bovine serum, antibiotic, and antifungal, and maintained in ideal conditions. Cells were treated with 25 µM, 50 µM, 100 µM, 150 µM and 200 µM of caffeic acid and dacarbazine at 1 mg/mL. We verified the effect on cell viability and cell death, apoptosis, cell cycle, colony formation and gene expression of caspases. Results showed a decrease in cell viability, cell death induction by apoptosis, inhibition of colony formation, modulation of cell cycle and alterations in gene expression of caspases after caffeic acid treatment. These results suggest an antitumor effect of the compound on SK-Mel-28 cells. This study provides original information on mechanisms by which caffeic acid may play a key role in preventing tumor progression in human melanoma cells.

Surface immunoglobulins of erythrocytes and platelets in dogs naturally infected by Rangelia vitalii.

Rangelia vitalii is a protozoan of the Babesiidae family that parasitizes domestic and wild dogs in South American countries. The main laboratory findings in blood samples from animals infected by R. vitalii are anemia and thrombocytopenia. The aim of this study was to detect IgM and IgG immunoglobulins on the surface of red blood cells and platelets, as well as to determine the percentage of reticulated platelets and reticulocytes in dogs naturally infected by R. vitalii. Blood samples from twenty dogs seen at the Veterinary Hospital of the Federal University of Santa Maria (UFSM) were divided into two groups: the diseased group consisted of blood samples from 10 animals with the diagnosis of rangeliosis, and the healthy group (control) consisted of samples from 10 healthy animals. All diseased dogs showed normocytic normochromic anemia but showed no differences (p > 0.05) in reticulocyte counts compared to healthy dogs. Moreover, IgM and IgG immunoglobulins were detected on the surface of the plasma membrane of red blood cells from both groups, but the amounts did not differ between groups (p > 0.05). Thrombocytopenia in infected animals was classified as severe. The percentage of reticulated platelets was higher (p < 0.001) in diseased dogs than in healthy animals. Diseased animals showed more IgM immunoglobulins bound to the surface of platelets than did the healthy group (p < 0.001). However, the amount of IgG bound to the surface of platelets was not different between groups. In conclusion, we showed that R. vitalii caused immune-mediated thrombocytopenia since IgM immunoglobulins were found on the surface of platelets of diseased dogs. We suggest that the binding of immunoglobulins on platelet surfaces contributes to early destruction of these cells and, consequently, alterations in hemostasis. An increase in reticulated platelets was noted in response to thrombocytopenia, indicating active thrombopoiesis.