Cx40 Levels Regulate Hypoxia-Induced Changes in the Migration, Proliferation, and Formation of Gap Junction Plaques in an Extravillous Trophoblast Cell Model.

BACKGROUND: Extravillous trophoblasts (EVTs) form stratified columns at the placenta-uterus interface. In the closest part to fetal structures, EVTs have a proliferative phenotype, whereas in the closest part to maternal structures, they present a migratory phenotype. During the placentation process, Connexin 40 (Cx40) participates in both the proliferation and migration of EVTs, which occurs under hypoxia. However, a possible interaction between hypoxia and Cx40 has not yet been established. METHODS: We developed two cellular models, one with "low Cx40" (Jeg-3), which reflected the expression of this protein found in migratory EVTs, and one with "high Cx40" (Jeg-3/hCx40), which reflected the expression of this protein in proliferative cells. We analyzed the migration and proliferation of these cells under normoxic and hypoxic conditions for 24 h. Jeg-3 cells under hypoxia increased their migratory capacity over their proliferative capacity. However, in Jeg-3/hCx40, the opposite effect was induced. On the other hand, hypoxia promoted gap junction (GJ) plaque formation between neighboring Jeg-3 cells. Similarly, the activation of a nitro oxide (NO)/cGMP/PKG-dependent pathway induced an increase in GJ-plaque formation in Jeg-3 cells. CONCLUSIONS: The expression patterns of Cx40 play a crucial role in shaping the responses of EVTs to hypoxia, thereby influencing their migratory or proliferative phenotype. Simultaneously, hypoxia triggers an increase in Cx40 gap junction (GJ) plaque formation through a pathway dependent on NO.

[Optical and mechanical properties of translucent zirconium as an optimal restorative material in fixed prosthesis: A review of the literature]. / Propiedades ópticas y mecánicas del zirconio translúcido como material restaurador óptimo en prótesis fija: Una revisión de la literatura.

Introduction: The main consequence of not treating tooth decay in time is the total or partial loss of the tooth. One of the alternatives to replace the lost tooth and return the functions is through fixed prostheses. Today there are 3 generations of yttrium-stabilized zirconium polycrystals (Y-TZP). Seeing that in the third Generation the yttrium content was increased to approximately 5% in moles (5Y), stabilizing the materials approximately 50% of cubic phase and 50% of tetragonal phase, thus giving a translucent zirconium (5Y) with a high aesthetics and greater naturalness to the dental crown. Objective: To identify the different optical and mechanical properties of translucent zirconium compared to other restorative materials used in fixed prostheses. Materials and methods: This narrative review evaluated 115 scientific articles from the Medline information sources (via PubMed), Science Direct, Scopus, SciELO and LILACS from the last 5 years, published in Spanish, Portuguese and English. We included 51 articles that met the selection criteria which were randomized clinical trials and observational studies, in vitro studies and in vivo studies that evaluated the optical and mechanical properties of translucent zirconium as an optimal restorative material in fixed prostheses. We excluded systematic reviews, case reports and editorials. Results: It was observed that zirconium being a relatively new material and in constant evolution has studies mostly in vitro, among which stand out those that speak both of the mechanical and optical properties that vary depending on the generation to which the material belongs, as well as the adhesiveness of the material which is for now not viable, therefore, it is essential that more studies be carried out on this material. Conclusions: We can mention that zirconium has evolved over time, providing better optical properties, but as a consequence it has been reducing flexural strength and fracture toughness. However, this material provides good biocompatibility with oral structures. On the other hand, translucent zirconium according to studies is a non-recordable material, so new methods are sought to improve its adhesion.

Connexins in melanoma: Potential role of Cx46 in its aggressiveness.

Melanoma is the most aggressive skin cancer, and in metastatic advanced states, it is completely refractory to chemotherapy. Therefore, it is relevant to understand the molecular bases that rule their aggressiveness. Connexins (Cxs) are proteins that under normal physiological conditions participate in intercellular communication, via the exchange of signaling molecules between the cytoplasm and extracellular milieu and the exchange of ions/second messengers between the cytoplasm of contacting cells. These proteins have shown important roles in cancer progression, chemo- and radiotherapy resistance, and metastasis. Accordingly, Cx26 and Cx43 seem to play important roles in melanoma progression and metastasis. On the other hand, Cx46 is typically expressed in the eye lens, where it seems to be associated with oxidative stress protection in fiber lens cells. However, in the last decade, Cx46 expression has been associated with breast and brain cancers, due to its role in potentiation of both extracellular vesicle release and cancer stem cell-like properties. In this review, we analyzed a potential role of Cx46 as a new biomarker and therapeutic target in melanoma.

Cx46 hemichannel modulation by nitric oxide: Role of the fourth transmembrane helix cysteine and its possible involvement in cataract formation.

Under normal conditions, connexin (Cx) hemichannels have a low open probability, which can increase under pathological conditions. Since hemichannels are permeable to relatively large molecules, their exacerbated activity has been linked to cell damage. Cx46 is highly expressed in the lens and its mutations have been associated to cataract formation, but it is unknown whether Cx46 has a role in non-genetic cataract formation (i.e. aging and diabetes). Nitric oxide (NO) is a key element in non-genetic cataract formation and Cx46 hemichannels have been shown to be sensitive to NO. The molecular mechanisms of the effects of NO on Cx46 are unknown, but are likely to result from Cx46 S-nitrosation (also known as S-nitrosylation). In this work, we found that lens opacity was correlated with Cx46 S-nitrosation in an animal model of cataract. Consistent with this result, a NO donor increased Cx46 S-nitrosation and hemichannel opening in HLE-B3 cells (cell line derived from human lens epithelial cells). Mutagenesis studies point to the cysteine located in the fourth transmembrane helix (TM4; human C212, rat C218) as the NO sensor. Electrophysiological studies performed in Xenopus oocytes revealed that rat Cx46 hemichannels are sensitive to different NO donors, and that the presence of C218 is necessary to observe the NO donors' effects. Unexpectedly, gap junctions formed by Cx46 were insensitive to NO or the reducing agent dithiothreitol. We propose that increased hemichannel opening and/or changes in their electrophysiological properties of human Cx46 due to S-nitrosation of the cysteine in TM4 could be an important factor in cataract formation.

Trypanosoma cruzi diversity in the Gran Chaco: mixed infections and differential host distribution of TcV and TcVI.

The transmission cycles of Trypanosoma cruzi in the Gran Chaco are complex networks involving domestic and wild components, whose interrelationships are not well understood. Knowing the circuit of transmission of the different Discrete Typing Units (DTUs) of T. cruzi in the complex environment of the Chaco region is relevant to understanding how the different components (reservoirs, vectors, ecotopes) interact. In the present study we identified the DTUs infecting humans and dogs in two rural areas of the Gran Chaco in Argentina, using molecular methods which avoid parasite culture. Blood samples of humans and dogs were typified by PCR-DNA blotting and hybridization assays with five specific DNA probes (TcI, TcII, TcIII, TcV and TcVI). PCR analyses were performed on seropositive human and dog samples and showed the presence of T. cruzi DNA in 41.7% (98/235) and 53% (35/66) samples, respectively. The identification of infective DTUs was determined in 83.6% (82/98) and 91.4% (32/35) in human and dog samples, respectively. Single infections (36.7% - 36/98) and a previously not detected high proportion of mixed infections (47.9% - 47/98) were found. In a 15.3% (15/98) of samples the infecting DTU was not identified. Among the single infections TcV was the most prevalent DTU (30.6% - 30/98) in human samples; while TcVI (42.8% - 15/35) showed the highest prevalence in dog samples. TcV/TcVI was the most prevalent mixed infection in humans (32.6% - 32/98); and TcI/TcVI (14.3% - 5/35) in dogs. Significant associations between TcV with humans and TcVI with dogs were detected. For the first time, the presence of TcIII was detected in humans from this region. The occurrence of one human infected whit TcIII (a principally wild DTU) could be suggested the emergence of this, in domestic cycles in the Gran Chaco.

[Reactivity of GST-SAPA antigen of Trypanosoma cruzi against sera from patients with Chagas disease and leishmaniasis]. / Reactividad del antígeno GST-SAPA de Trypanosoma cruzi frente a sueros de pacientes con enfermedad de Chagas y leishmaniasis.

Serologic diagnosis of Trypanosoma cruzi infection is important due to the limited sensitivity of direct parasitologic methods for diagnosis in the indeterminate and chronic phases of disease. SAPA antigen has been used in several studies and has been shown to be a good marker for use in the diagnosis of T. cruzi infection. Chagas disease and leishmaniasis are endemic in northern Salta with overlapping zones of transmission, which frequently leads to T. cruzi-Leishmania spp. mixed infections. Diagnosis is complicated by the fact that there is significant cross-reactivity when non-specific antigens are used. We evaluated the reactivity of GST-SAPA antigen in the ELISA test (ELISA-SAPA) against sera from persons infected with T. cruzi (n = 154), leishmaniasis (n = 66), mixed infections (29), and healthy controls (n = 28) using commercial ELISA and IHA kits as reference tests. For ELISA-SAPA the sensitivity, specificity and kappa index were calculated for detection of T. cruzi infection. Among sera from patients infected with leishmaniasis, 30.5% of co-infections were detected. ELISA-SAPA sensitivity was 97.1% (confidence interval 95%: 94.5-99.9), specificity was 100% (confidence interval 95%: 99.4-100), and kappa index was 96% (confidence interval 95%: 93-99%), for detection of T. cruzi infection. Sensitivity, specificity and kappa indices have shown a high efficiency of ELISA-SAPA.

Reactividad del antígeno GST-SAPA de Trypanosoma cruzi frente a sueros de pacientes con enfermedad de Chagas y leishmaniasis / Reactivity of GST-SAPA antigen of Trypanosoma cruzi against sera from patients with Chagas disease and leishmaniasis

El diagnóstico serológico de la infección producida por Trypanosoma cruzi es de especial relevancia dado que los métodos parasitológicos tienen, en las fases indeterminada y crónica, una sensibilidad limitada. El antígeno SAPA fue usado en diversos estudios y demostró ser un buen candidato para el diagnóstico de la infección por T. cruzi. La enfermedad de Chagas y la leishmaniasis son endémicas en el norte de Salta, con posibles zonas de solapamiento. Este hecho suele dar lugar a infecciones mixtas T. cruzi-Leishmania spp., con la consecuente probabilidad de diagnóstico cruzado cuando se usan antígenos no específicos. Se evaluó la reactividad del antígeno GST-SAPA en la prueba de ELISA (ELISA-SAPA) frente a sueros de personas infectadas por T. cruzi (n = 154), con leishmaniasis (n = 66), infecciones mixtas (n = 29) y controles negativos (n = 28), usando como pruebas de referencia para el diagnóstico de la infección por T. cruzi kits comerciales de ELISA y HAI. Se calculó la sensibilidad, especificidad e índice de concordancia kappa de la prueba de ELISA-SAPA, para la detección de infección por T. cruzi. Entre los sueros de pacientes con leishmaniasis estudiados se detectó un 30.5% de infecciones mixtas. Para la detección de infección por T. cruzi, ELISA-SAPA mostró una sensibilidad del 97.1% (intervalo de confianza del 95%: 94.5-99.9), una especificidad del 100% (intervalo de confianza del 95%: 99.5-100) y un índice de concordancia kappa de 96 (intervalo de confianza del 95%:93-99%), comparado con las pruebas serológicas comerciales. Los valores de sensibilidad, especificidad y concordancia calculados muestran una alta eficiencia de ELISA-SAPA.

Serologic diagnosis of Trypanosoma cruzi infection is important due to the limited sensitivity of direct parasitologic methods for diagnosis in the indeterminate and chronic phases of disease. SAPA antigen has been used in several studies and has been shown to be a good marker for use in the diagnosis of T. cruzi infection. Chagas disease and leishmaniasis are endemic in northern Salta with overlapping zones of transmission, which frequently leads to T. cruzi-Leishmania spp. mixed infections. Diagnosis is complicated by the fact that there is significant cross-reactivity when non-specific antigens are used. We evaluated the reactivity of GST-SAPA antigen in the ELISA test (ELISA-SAPA) against sera from persons infected with T. cruzi (n = 154), leishmaniasis (n = 66), mixed infections (29), and healthy controls (n = 28) using commercial ELISA and IHA kits as reference tests. For ELISA-SAPA the sensitivity, specificity and kappa index were calculated for detection of T. cruzi infection. Among sera from patients infected with leishmaniasis, 30.5% of co-infections were detected. ELISA-SAPA sensitivity was 97.1% (confidence interval 95%: 94.5-99.9), specificity was 100% (confidence interval 95%: 99.4-100), and kappa index was 96% (confidence interval 95%: 93-99%), for detection of T. cruzi infection. Sensitivity, specificity and kappa indices have shown a high efficiency of ELISA-SAPA.