Itraconazole in human medicine and veterinary practice.

Diagnosis and management of fungal infections are challenging in both animals and humans, especially in immunologically weakened hosts. Due to its broad spectrum and safety profile when compared to other antifungals, itraconazole (ITZ) has been widely used in the treatment and prophylaxis of fungal infections, both in human and veterinary medicine. The dose and duration of management depend on factors such as the type of fungal pathogen, the site of infection, sensitivity to ITZ, chronic stages of the disease, the health status of the hosts, pharmacological interactions with other medications and the therapeutic protocol used. In veterinary practice, ITZ doses generally vary between 3 mg/kg and 50 mg/kg, once or twice a day. In humans, doses usually vary between 100 and 400 mg/day. As human and veterinary fungal infections are increasingly associated, and ITZ is one of the main medications used, this review addresses relevant aspects related to the use of this drug in both clinics, including case reports and different clinical aspects available in the literature.

Feline sporotrichosis: Characterization of cutaneous and extracutaneous lesions using different diagnostic methods.

Sporotrichosis is a mycotic infection of the cutaneous and subcutaneous tissues caused by Sporothrix spp. that can also cause extracutaneous manifestations. This study aimed to characterize cutaneous and extracutaneous sporotrichosis lesions in cats. Over 1 year, 102 cats rescued by the Zoonoses Control Center of Belo Horizonte, Brazil, euthanized with clinical suspicion of feline sporotrichosis were evaluated. After euthanasia, the animals were evaluated by macroscopic, cytological, histopathological, and immunohistochemistry (IHC) examinations; fungal culture; and polymerase chain reaction (PCR). Sporothrix infection was identified by at least one diagnostic technique in all cats (n = 102) evaluated by postmortem examination, including 26/28 cases (93%) evaluated by IHC, 66/90 cases (73%) evaluated by cytology, 70/102 cases (68.6%) evaluated by histopathology, and 62/74 cases (84%) evaluated by fungal culture. Two cats had positive results only by fungal culture. Cytology and histopathology examinations were effective in diagnosing sporotrichosis, although IHC was needed to confirm the diagnosis in cats with low fungal loads. Sporothrix brasiliensis was confirmed by the sequencing of 3 samples. Skin lesions were characterized mainly by pyogranulomatous to granulomatous dermatitis (frequently with subcutaneous inflammation) with different intensities of Sporothrix spp. yeast. Extracutaneous findings associated with sporotrichosis included rhinitis or rhinosinusitis, lymphadenitis, pneumonia, meningitis, periorchitis, conjunctivitis, and glossitis. Extracutaneous infections were observed in 74/102 cases, and a possible association between the chronicity of the disease and the higher pathogenicity of this fungal species in cats requires further investigation.

The hypoxia-inducible factor EPAS1 is required for spermatogonial stem cell function in regenerative conditions.

In this study we explored the role of hypoxia and the hypoxia-inducible transcription factor EPAS1 in regulating spermatogonial stem cell (SSC) function in the mouse testis. We have demonstrated that SSCs reside in hypoxic microenvironments in the testis through utilization of the oxygen-sensing probe pimonidazole, and by confirming the stable presence of EPAS1, which is degraded at >5% O2. Through the generation of a germline-specific Epas1 knockout mouse line, and through modulation of EPAS1 levels in primary cultures of spermatogonia with the small drug molecule Daprodustat, we have demonstrated that EPAS1 is required for robust SSC function in regenerative conditions (post-transplantation and post-chemotherapy), via the regulation of key cellular processes such as metabolism. These findings shed light on the relationship between hypoxia and male fertility and will potentially facilitate optimization of in vitro culture conditions for infertility treatment pipelines using SSCs, such as those directed at pediatric cancer survivors.

Epidemiological study of canine transmissible venereal tumor (CTVT) in Brazil, 2000-2020.

Canine transmissible venereal tumor (CTVT) is a contagious neoplasm, mainly transmitted through coitus. This round cell mesenchymal tumor is common in Brazil, often located in the genitalia although extragenital presentations may also occur, such as cutaneous, oral, and nasal forms. The objective of this study was to perform an epidemiological analysis of CTVT from published data in the recent academic literature to systematically demonstrate the distribution of CTVT in Brazil, identify the frequency of this neoplasm and its main diagnostic tests, and characterize its main clinical manifestations in Brazil. For such purpose, it was analyzed the scientific publications with cases of CTVT in Brazil, in English or Portuguese, published between 2000-2020. The CTVT was identified in 19 Brazilian states plus the Federal District, totaling 3,622 cases across the national territory, with the largest number of cases recorded in the Southeast region. The cytological exam was the most used for the diagnosis of CTVT (89.2 %), followed by histopathological (37.8 %) and immunohistochemistry (13.5 %)1 . Predominant epidemiological aspects of CTVT identified in the study were: Mixed breed dogs (75.2 %), females (62.5 %), in adulthood (between 2 and 7 years) and dogs with free extra outdoor access (91.1 %). Genital presentation was the most frequent in the literature (86 %), followed by cutaneous (21.8 %), nasal (10 %), oral and lymph nodes presentations (10-5 %) and less frequent manifestations as ocular and anal/perianal (< 5 %). CTVT is a neoplasm widely distributed in Brazil, highly frequent and with several forms of clinical presentation, which can be underdiagnosed if there is no adequate knowledge of this tumor and its epidemiological characteristics. The extragenital manifestations of the neoplasm need further studies for its better characterization and more precise definition of its frequencies.

Implementation of an Animal Sporotrichosis Surveillance and Control Program, Southeastern Brazil.

We report the implementation of an animal sporotrichosis surveillance and control program that evaluates strategies to identify suspected and infected cats in a municipality in southeastern Brazil. All adopted measures reinforced the program, although strategies had different abilities to detect the presence of infection.

Mandible lymphoma: an aggressive osteolytic lesion

Background: Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-hodgkin's lymphoma. In oral cavity represents approximately 2% of all malignancies. Case presentation: This report describes a rare mandibular involvement of DLBCL. A 56 year-old man was referred for evaluation of left mandible pain. In the anamnesis, the patient informed to be treating tooth pain in lasting 6 months. On oral evaluation, an intense mobility of the left mandibular second molar and a swelling in posterior left mandible were observed. Computed tomography showed a large osteolytic lesion affecting both mandibular body and ramus. An incisional biopsy was performed and according to histopathological and imumnohistochemical features, DLBCL was diagnosed. The treatment consisted of 8 cycles of R-CHOP and adjuvant radiotherapy. He is asymptomatic after 6 years. Conclusion: This case showed a rare bone presentation of DLBCL and such tumor should be considered as differential diagnosis of osteolytic lesion of the mandible.

Leishmania infantum pyridoxal kinase evaluated in a recombinant protein and DNA vaccine to protects against visceral leishmaniasis.

Leishmania infantum pyridoxal kinase (PK) protein was characterized after an immunoproteomics screening performed with the sera from patients suffering visceral leishmaniasis (VL). Since it was recognized by sera of mammalian hosts infected by a viscerotropic Leishmania species, PK could emerge as a new vaccine candidate against disease, due to its antigenicity and immunogenicity. In this context, in the present study, the effects of the immunization using PK were evaluated when administered as a DNA plasmid (pDNAA3/PK) or recombinant protein (rPK) plus saponin. The immune response elicited by both vaccination regimens reduced in significant levels the parasite load in spleen, liver, draining lymph nodes and bone marrow, being associated with the development of Th1-type immune response, which was characterized by high levels of IFN-γ, IL-12, GM-CSF, and specific IgG2a antibody, besides low production of IL-4, IL-10, and protein and parasite-specific IgG1 antibodies. CD8+ T cells were more important in the IFN-γ production in the pDNAA3/PK group, while CD4+ T cells contributed more significantly to production of this cytokine in the rPK/Saponin group. In addition, increased IFN-γ secretion, along with low levels of IL-10, were found when PBMCs from VL patients after treatment and healthy individuals were stimulated with the protein. In conclusion, when administered either as a DNA plasmid or recombinant protein plus adjuvant, PK can direct the immune response towards a Th1-type immune profile, protecting mice against L. infantum challenge; therefore, it can be seen as a promising immunogen against human VL.

Evaluating nuclear translocation of surface receptors: recommendations arising from analysis of CD44.

CD44 is a transmembrane receptor that acts as adhesion protein, fundamentally recognizing hyaluronan, an essential component of the extracellular matrix. It has a well-established functional association with cancer metastasis, particularly the CD44 variant forms which are considered essential markers of cancer stem cells. CD44 itself lacks intrinsic kinase activity but rather engages in signalling through specific interactions with kinases and other signalling components. Proteolysis within its transmembrane region also leads to release of the CD44 cytoplasmic domain, which can translocate to the nucleus and regulate transcription. A third signalling modality has been reported where the intact CD44 receptor translocates to the nucleus. Here, we investigated the latter using imaging techniques together with biochemical analyses. Our findings support observations where CD44 is cleaved prior to nuclear translocation and challenges the evidence for the presence of intact CD44 receptors in the cell nucleus. Conclusions regarding the presence of intact CD44 in the cell nucleus as a signalling modality, therefore, require re-evaluation. We highlight artefacts and common technical issues associated with these experiments that can lead to misinterpretation.

Molecular typing of Leptospira interrogans serovar Hardjo isolates from leptospirosis outbreaks in Brazilian livestock.

BACKGROUND: Leptospirosis is caused by pathogenic spirochetes of the genus Leptospira spp. This zoonotic disease is distributed globally and affects domestic animals, including cattle. Leptospira interrogans serogroup Sejroe serovar Hardjo and Leptospira borgpetersenii serogroup Sejroe serovar Hardjo remain important species associated with this reproductive disease in livestock production. Previous studies on Brazilian livestock have reported that L. interrogans serovar Hardjo is the most prevalent leptospiral agent in this country and is related to clinical signs of leptospirosis, which lead to economic losses in production. Here, we described the isolation of three clinical strains (Norma, Lagoa and Bolivia) obtained from leptospirosis outbreaks that occurred in Minas Gerais state in 1994 and 2008. RESULTS: Serological and molecular typing using housekeeping (secY and 16SrRNA) and rfb locus (ORF22 and ORF36) genes were applied for the identification and comparative analysis of Leptospira spp. Our results identified the three isolates as L. interrogans serogroup Sejroe serovar Hardjo and confirmed the occurrence of this bacterial strain in Brazilian livestock. Genetic analysis using ORF22 and ORF36 grouped the Leptospira into serogroup Sejroe and subtype Hardjoprajitno. Genetic approaches were also applied to compare distinct serovars of L. interrogans strains by verifying the copy numbers of the IS1500 and IS1533 insertion sequences (ISs). The IS1500 copy number varied among the analyzed L. interrogans strains. CONCLUSION: This study provides evidence that L. interrogans serogroup Sejroe serovar Hardjo subtype Hardjoprajitno causes bovine leptospirosis in Brazilian production. The molecular results suggested that rfb locus (ORF22 and ORF36) could improve epidemiological studies by allowing the identification of Leptospira spp. at the serogroup level. Additionally, the IS1500 and IS1533 IS copy number analysis suggested distinct genomic features among closely related leptospiral strains.

Trends in animal rabies surveillance in the endemic state of Minas Gerais, Brazil.

Rabies is a viral zoonosis affecting mammal species and causes large economic losses. Included among the neglected diseases, it is still insufficiently addressed by governments and the international community, despite formal surveillance and control programs. This study used a dataset of 10,112 rabies diagnoses in animals provided by the Brazilian passive surveillance system from 2001 to 2012. The positivity rate of the tested samples was 26.4%, and a reduction in the total samples sent during the last six years was observed. The kernel density map indicated case concentration in the south region and a decrease in density of rabies cases in the second period studied (2007 to 2012). The directional trend of positive rabies diagnoses remained in the south region, as shown by the standard deviational ellipse. The spatial scan statistic identified three large clusters of positive diagnoses, one in the first period (2001-2006) and two in the second period (2007-2012), indicating an expansion of risk areas. The decrease in rabies cases from 2006 to 2012 does not necessarily reflect lower viral circulation or improvement in actions by epidemiological surveillance; this decrease could indicate a deficiency in epidemiological surveillance during the observation period due to the increase in the silent areas. Surveillance should maintain an increasing or constant number of tests during the years in addition to a reduction in the number of outbreaks of rabies, which would indicate a lower positivity rate. The findings in this study indicate deterioration in the effectiveness of the passive surveillance for rabies. The number of rabies cases, total number of tests performed and positivity rate are good indicators for evaluating passive surveillance. This paper can function as a guide for the assessment and improvement of the actions in passive surveillance of rabies.

Biocatalysis for desymmetrization and resolution of stereocenters beyond the reactive center: How far is far enough?

The kinetic resolution of racemates and desymmetrization are the most common approaches to the preparation of enantiomerically enriched compounds. These procedures allow the access of high valuable, chiral building blocks for many purposes in academic or industrial R&D endeavors. Nevertheless, the scope of stereochemistry recognition in biotransformations usually occurs at the site of the transformation or when it is close to it (not more than 3 bonds). However, there are a growing number of enzymatic transformations which surpass the limits of stereorecognition of remote chiral (or prochiral) centers. In this account, we would like to present some aspects of biocatalyzed remote resolutions and remote desymmetrizations to call attention for these challenging transformations.

Macrophage migration inhibitory factor engages PI3K/Akt signalling and is a prognostic factor in metastatic melanoma.

BACKGROUND: Macrophage migration inhibitory factor (MIF) is a widely expressed cytokine involved in a variety of cellular processes including cell cycle regulation and the control of proliferation. Overexpression of MIF has been reported in a number of cancer types and it has previously been shown that MIF is upregulated in melanocytic tumours with the highest expression levels occurring in malignant melanoma. However, the clinical significance of high MIF expression in melanoma has not been reported. METHODS: MIF expression was depleted in human melanoma cell lines using siRNA-mediated gene knockdown and effects monitored using in vitro assays of proliferation, cell cycle, apoptosis, clonogenicity and Akt signalling. In silico analyses of expression microarray data were used to correlate MIF expression levels in melanoma tumours with overall patient survival using a univariate Cox regression model. RESULTS: Knockdown of MIF significantly decreased proliferation, increased apoptosis and decreased anchorage-independent growth. Effects were associated with reduced numbers of cells entering S phase concomitant with decreased cyclin D1 and CDK4 expression, increased p27 expression and decreased Akt phosphorylation. Analysis of clinical outcome data showed that MIF expression levels in primary melanoma were not associated with outcome (HR = 1.091, p = 0.892) whereas higher levels of MIF in metastatic lesions were significantly associated with faster disease progression (HR = 2.946, p = 0.003 and HR = 4.600, p = 0.004, respectively in two independent studies). CONCLUSIONS: Our in vitro analyses show that MIF functions upstream of the PI3K/Akt pathway in human melanoma cell lines. Moreover, depletion of MIF inhibited melanoma proliferation, viability and clonogenic capacity. Clinically, high MIF levels in metastatic melanoma were found to be associated with faster disease recurrence. These findings support the clinical significance of MIF signalling in melanoma and provide a strong rationale for both targeting and monitoring MIF expression in clinical melanoma.

Dual processing of FAT1 cadherin protein by human melanoma cells generates distinct protein products.

The giant cadherin FAT1 is one of four vertebrate orthologues of the Drosophila tumor suppressor fat. It engages in several functions, including cell polarity and migration, and in Hippo signaling during development. Homozygous deletions in oral cancer suggest that FAT1 may play a tumor suppressor role, although overexpression of FAT1 has been reported in some other cancers. Here we show using Northern blotting that human melanoma cell lines variably but universally express FAT1 and less commonly FAT2, FAT3, and FAT4. Both normal melanocytes and keratinocytes also express comparable FAT1 mRNA relative to melanoma cells. Analysis of the protein processing of FAT1 in keratinocytes revealed that, like Drosophila FAT, human FAT1 is cleaved into a non-covalent heterodimer before achieving cell surface expression. The use of inhibitors also established that such cleavage requires the proprotein convertase furin. However, in melanoma cells, the non-cleaved proform of FAT1 is also expressed at the cell surface together with the furin-cleaved heterodimer. Moreover, furin-independent processing generates a potentially functional proteolytic product in melanoma cells, a persistent 65-kDa membrane-bound cytoplasmic fragment no longer in association with the extracellular fragment. In vitro localization studies of FAT1 showed that melanoma cells display high levels of cytosolic FAT1 protein, whereas keratinocytes, despite comparable FAT1 expression levels, exhibited mainly cell-cell junctional staining. Such differences in protein distribution appear to reconcile with the different protein products generated by dual FAT1 processing. We suggest that the uncleaved FAT1 could promote altered signaling, and the novel products of alternate processing provide a dominant negative function in melanoma.

Environmental novelty and illumination modify ethanol-induced open-field behavioral effects in mice.

Both spontaneous and drug-induced animal behaviors can be modified by exposure to novel stimuli or different levels of environmental illumination. However, research into how these factors specifically impact ethanol (ETH)-induced behavioral effects is currently lacking. We aimed to investigate the effects of these two factors, considered separately or in conjunction, on ETH-induced acute hyperlocomotor effect and its sensitization in adult male Swiss mice. Mice were placed in a novel or familiar open-field under normal light (200 lx) or low light (9 lx) immediately after receiving an ip injection of either 1.8 g/kg ETH or saline (SAL). After 7 days, all animals received an ip challenge injection of 1.8 g/kg ETH, and were placed in the open-field under the same light conditions described above. Novelty increased central locomotion and decreased grooming, while low light increased grooming. Acute ETH administration increased both total and peripheral locomotion and these effects were potentiated by low light. Both low light and novelty were able to facilitate ETH-induced locomotor sensitization, which was detected by the central locomotion parameter. However, there was no synergism between the effects of these two modulating factors on ETH-induced behavioral sensitization. We conclude that both the acute behavioral effects of ETH and behavioral sensitization induced by previous administration of this drug can be critically modified by environmental factors. In addition, our study stresses the importance of using different behavioral parameters to evaluate the interaction between environmental factors and ETH effects.

Neurotoxicity of cadmium on immature hippocampus and a neuroprotective role for p38 MAPK.

The developing brain is very sensitive to damage by toxic agents, many of which only manifest in adulthood. Cadmium [Cd(II)] is an environmental pollutant which is widely used in industry and is a constituent of tobacco smoke. Exposure to Cd(II) has been linked to detrimental effects on mammalian cells including neural cells. We have investigated the action of Cd(II) on immature hippocampus by assessing cell viability and modulation of AKT/PKB and mitogen-activated protein kinase (MAPK) family members including extracellular signal-regulated kinase (ERK)-1/2, p38 MAPK and c-Jun N-terminal kinases (JNK). Hippocampal slices from immature rats (postnatal day 14; PN14) were incubated with Cd(II) (5-200 microM) for 3h and the effects on protein phosphorylation were analyzed by western blotting. Phosphorylation of p38(MAPK) was enhanced by Cd(II) at all doses tested. Cd(II) also stimulated the phosphorylation of ERK1/2 in a concentration-dependent manner. However, the phosphorylation of JNK and AKT was not altered by the metal. Moreover, Cd(II) reduced cell viability, as measured by MTT reduction. Inhibition of p38 MAPK by SB203580 aggravated the acute Cd(II)-induced impairment of cell viability, whereas inhibition of MEK by PD98059 did not alter the effects of Cd(II). The present data suggest that in immature hippocampal cells p38 MAPK may be a part of signaling pathway that counteracts acute Cd(II) neurotoxicity. In conclusion, our results showed that Cd(II) impairs cell viability and disturbs MAPKs pathways in an important developmental stage for synaptic organization.

Biochemical alterations in juvenile carp (Cyprinus carpio) exposed to zinc: glutathione reductase as a target.

The aim of this study was to investigate biochemical changes in juvenile carp (Cyprinus carpio) exposed to zinc chloride (10, 30 and 100 microM) for a period of 48 h. Zinc exposure caused a concentration-dependent reduction in glutathione reductase (GR) activity in gills, liver and brain. Gill glutathione S-transferase (GST) was reduced when animals were exposed to the highest concentration of 100 microM zinc. The phosphorylation of p38(MAPK) increased in the brain of fish exposed to zinc 100 microM, while phosphorylation of the extracellular signal-regulated protein kinase 1/2 (ERK1/2) and c-Jun N-terminal protein kinase 1/2 (JNK1/2) remained unchanged. Expression of proteins HSP60 and HSP70 were not affected by zinc exposure. Considering the significant concentration-dependent inhibition of GR in all tissues analyzed, this enzyme could be a potential biomarker of exposure to zinc, which has to be confirmed.

Cadmium stimulates MAPKs and Hsp27 phosphorylation in bovine adrenal chromaffin cells.

Cadmium (Cd(2+)) is a common environmental pollutant, which is widely used in industry and is a constituent of tobacco smoke. Exposure to this heavy metal has been linked to a wide range of detrimental effects on mammalian cells. In this study, the action of Cd(2+) on protein phosphorylation in bovine adrenal chromaffin cells (BACCs) was examined. Cells were incubated with (32)Pi in the presence of Cd(2+) (1-50 microM) and proteins were separated by one- or two-dimensional electrophoresis. An increase in the phosphorylation of BACCs proteins, without changing cell viability, was observed in response to Cd(2+) (5-50 microM). Particularly at three spots, with molecular weight of 25kDa and isoeletric point range 4.0-4.5, which were identified as phosphorylated isoforms of the heat shock protein of 27kDa (Hsp27). Phosphorylation of the p38(MAPK), a member of mitogen-activated protein kinase (MAPK) family, was stimulated by Cd(2+) over the same concentration range and it was the major upstream protein kinase involved in the phosphorylation of all three spots of Hsp27. Cd(2+) also stimulated the phosphorylation of other MAPK family member, the extracellular signal-regulated kinase (ERK)-1/2. Therefore, primary adrenal chromaffin cells are a target for Cd(2+) and both the ERK1/2 and the p38(MAPK) are activated. Additionally, Hsp27 is highly phosphorylated in response to the metal exposure, due to p38(MAPK) activation. These biochemical effects of Cd(2+) might disrupt the normal secretory function of these cells.

Exposure of C6 glioma cells to Pb(II) increases the phosphorylation of p38(MAPK) and JNK1/2 but not of ERK1/2.

Pb(II) is a neurotoxic pollutant that produces permanent cognitive deficits in children. Pb(II) can modulate cell signaling pathways and cell viability in a variety of cell types. However, these actions are not well demonstrated on glial cells, which represent an important target for metals into the central nervous system. The present work was undertaken to determine the ability of Pb(II) in modulating the activity of mitogen activated protein kinases (MAPKs) in cultures of C6 rat glioma cells, a useful functional model for the study of astrocytes. Additionally, cell viability was analyzed by measurement of MTT reduction. Cells were exposed to lead acetate 0.1, 1, 10 microM for 24 and 48 h. MAPKs activation - in particular ERK1/2, p38(MAPK) and JNK1/2 - were analyzed by western blotting. Results showed that 10 microM Pb(II) treatment for 24 h caused a discrete stimulation of p38(MAPK) phosphorylation. However, 1 and 10 microM Pb(II) treatment for 48 h provoked a significant stimulation in the phosphorylation state of p38(MAPK) and JNK1/2. The phosphorylation state of ERK1/2 was not modified by any Pb(II) treatment. Moreover, data indicate that at 48 h treatment even 1 microM Pb(II) can be cytotoxic, causing impairment on cell viability. Therefore, depending on a long incubation period, a significant concomitant activation of p38(MAPK) and JNK1/2 by Pb(II) took place in parallel with the impairment of C6 glioma cells viability.

Lead stimulates ERK1/2 and p38MAPK phosphorylation in the hippocampus of immature rats.

Lead (Pb(2+)) is widely recognized as a neurotoxicant whose mechanisms of action are not completely established. We have previously demonstrated that Pb(2+) can activate the p38(MAPK) pathway and increase the phosphorylation of Hsp27 in bovine adrenal chromaffin cells and human SH SY5Y cells over a short incubation period (1 h). In the present work we analyzed the effects of Pb(2+) administered in vivo on the level and the phosphorylation state of ERK1/2 and p38(MAPK) in the hippocampus of immature rats. Rats were treated with lead acetate (2, 8 or 12 mg/kg, i.p.) or saline (control) over the 8th to 12th postnatal days, and hippocampal slices were prepared on the 14th day. The Pb(2+) level in the lead-treated animals increased 2.5-6-fold in the blood (3.0-6.0 microg/dl) and 2.0-3.0-fold in the forebrain (78-103 ng/g wet weight), compared to control (saline). The phosphorylation of both ERK1/2 and p38(MAPK) was significantly increased by prior exposure to Pb(2+) in vivo. In in vitro experiments, hippocampal slices from 14-day-old rats were exposed to Pb(2+) (1-10 microM) for 1 and 3 h. There were no changes in the phosphorylation state of ERK and p38(MAPK) for 1-h incubation, whereas a significant increase of ERK1/2 and p38(MAPK) phosphorylation by Pb(2+) (5 microM) was observed for the 3-h incubation. Cell viability measured using MTT was not modified in any of the conditions tested. These results indicate that the phosphorylation of hippocampal ERK1/2 and p38(MAPK) is stimulated by lead in a period of rapid brain development, an effect that may underlie, at least in part, the neurotoxicty elicited by this metal.