Sensitivity of the marine benthic copepod Tisbe biminiensis (copepoda, harpacticoida) to potassium dichromate and sediment particle size

For the future use of the marine benthic copepod Tisbe biminiensis in solid-phase sediment toxicological bioassays, the present study investigated the effect of muddy sediment from the Maracaípe estuary (northeastern Brazil), sediment particle size and the reference toxicant potassium dichromate on the species. Muddy sediment from Maracaípe can be used as control sediment, since it does not interfere in the copepod life-cycle and has metal contamination levels that are unlikely to produce any detrimental biological effects on benthic invertebrates. Neither survival nor fecundity was affected by grain size, suggesting that this species can be used with any kind of sediment from muddy to sandy. The sensitivity of T. biminiensis to K2Cr2O7 in acute tests was similar to that of other organisms. The LC50 (lethal concentration to 50% of the test organisms) medium values for T. biminiensis were 7.51, 4.68 and 3.19 mg L-1 for Cr in 48, 72 and 96 h, respectively. These results suggest that T. biminiensis is a promising organism for use in solid-phase sediment toxicity assessments.Visando o uso futuro do copépodo marinho bentônico Tisbe biminiensis em bioensaios toxicológicos de sedimentos na fase sólida, o presente estudo investigou o efeito do sedimento lamoso do estuário de Maracaípe (Nordeste do Brasil). Foram considerados a granolometria e o tóxico de referência dicromato de potássio sobre a espécie. O sedimento lamoso de Maracaípe pode ser usado como controle, uma vez que não interfere no ciclo de vida do copépodo e possui níveis de contaminação de metais que não causariam efeitos biológicos em invertebrados bentônicos. Nem a sobrevivência ou fecundidade foi afetada pelo tamanho do grão, sugerindo que esta espécie pode ser usada com qualquer tipo de sedimento, de lama a areia. A sensibilidade de T. biminiensis ao K2Cr2O7 em testes agudos foi similar a de outros organismos. Os valores de CL50 (concentração letal a 50% dos organismos) para T. biminiensis foram em média 7,51, 4,68 e 3,19 mg L-1 para o Cr em 48, 72 e 96h, respectivamente. Estes resultados sugerem que T. biminiensis é um organismo promissor para uso em avaliações de toxicidade com a fase sólida do sedimento

Kynurenine pathway in post-mortem prefrontal cortex and cerebellum in schizophrenia : relationship with monoamines and symptomatology

The cortico-cerebellar-thalamic-cortical circuit has been implicated in the emergence of psychotic symptoms in schizophrenia (SZ). The kynurenine pathway (KP) has been linked to alterations in glutamatergic and monoaminergic neurotransmission and to SZ symptomatology through the production of the metabolites quinolinic acid (QA) and kynurenic acid (KYNA). This work describes alterations in KP in the post-mortem prefrontal cortex (PFC) and cerebellum (CB) of 15 chronic SZ patients and 14 control subjects in PFC and 13 control subjects in CB using immunoblot for protein levels and ELISA for interleukins and QA and KYNA determinations. Monoamine metabolites were analysed by high-performance liquid chromatography and SZ symptomatology was assessed by Positive and Negative Syndrome Scale (PANSS). The association of KP with inflammatory mediators, monoamine metabolism and SZ symptomatology was explored. In the PFC, the presence of the anti-inflammatory cytokine IL-10 together with IDO2 and KATII enzymes decreased in SZ, while TDO and KMO enzyme expression increased. A network interaction analysis showed that in the PFC IL-10 was coupled to the QA branch of the kynurenine pathway (TDO-KMO-QA), whereas IL-10 associated with KMO in CB. KYNA in the CB inversely correlated with negative and general PANSS psychopathology. Although there were no changes in monoamine metabolite content in the PFC in SZ, a network interaction analysis showed associations between dopamine and methoxyhydroxyphenylglycol degradation metabolite. Direct correlations were found between general PANSS psychopathology and the serotonin degradation metabolite, 5-hydroxyindoleacetic acid. Interestingly, KYNA in the CB inversely correlated with 5-hydroxyindoleacetic acid in the PFC. Thus, this work found alterations in KP in two brain areas belonging to the cortico-cerebellar-thalamic-cortical circuit associated with SZ symptomatology, with a possible impact across areas in 5-HT degradation. The online version contains supplementary material available at 10.1186/s12974-021-02260-6

Biochemical and structural characterization of a novel arginine kinase from the spider <i>Polybetes pythagoricus</i>

Energy buffering systems are key for homeostasis during variations in energy supply. Spiders are the most important predators for insects and therefore key in terrestrial ecosystems. From biomedical interest, spiders are important for their venoms and as a source of potent allergens, such as arginine kinase (AK, EC 2.7.3.3). AK is an enzyme crucial for energy metabolism, keeping the pool of phosphagens in invertebrates, and also an allergen for humans. In this work, we studied AK from the Argentininan spider Polybetes pythagoricus (PpAK), from its complementary DNA to the crystal structure. The PpAK cDNA from muscle was cloned, and it is comprised of 1068 nucleotides that encode a 384-amino acids protein, similar to other invertebrate AKs. The apparent Michaelis-Menten kinetic constant (Km) was 1.7 mM with a kcat of 75 s-1. Two crystal structures are presented, the apoPvAK and PpAK bound to arginine, both in the open conformation with the active site lid (residues 310-320) completely disordered. The guanidino group binding site in the apo structure appears to be organized to accept the arginine substrate. Finally, these results contribute to knowledge of mechanistic details of the function of arginine kinase.Instituto de Investigaciones Bioquímicas de La Plat

Biochemical and structural characterization of a novel arginine kinase from the spider <i>Polybetes pythagoricus</i>

Energy buffering systems are key for homeostasis during variations in energy supply. Spiders are the most important predators for insects and therefore key in terrestrial ecosystems. From biomedical interest, spiders are important for their venoms and as a source of potent allergens, such as arginine kinase (AK, EC 2.7.3.3). AK is an enzyme crucial for energy metabolism, keeping the pool of phosphagens in invertebrates, and also an allergen for humans. In this work, we studied AK from the Argentininan spider Polybetes pythagoricus (PpAK), from its complementary DNA to the crystal structure. The PpAK cDNA from muscle was cloned, and it is comprised of 1068 nucleotides that encode a 384-amino acids protein, similar to other invertebrate AKs. The apparent Michaelis-Menten kinetic constant (Km) was 1.7 mM with a kcat of 75 s-1. Two crystal structures are presented, the apoPvAK and PpAK bound to arginine, both in the open conformation with the active site lid (residues 310-320) completely disordered. The guanidino group binding site in the apo structure appears to be organized to accept the arginine substrate. Finally, these results contribute to knowledge of mechanistic details of the function of arginine kinase.Instituto de Investigaciones Bioquímicas de La Plat

Acute effects of a session of electroconvulsive therapy on brain-derived neurotrophic factor plasma levels

Brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) are neurotrophins that play critical roles in brain neuronal function. Previous studies have established the association between BDNF and NGF signaling and severe mental disorders, but changes in BDNF plasma levels and electroconvulsive therapy (ECT) response are controversial. The aim of his study was to explore the acute effects of a single session of ECT on these neurotrophins signaling. Plasma levels of BDNF and NGF and their tyrosine kinase-type receptors expression in peripheral blood mononuclear cells (PBMCs) were determined before and two hours after a single ECT session in 30 subjects with a severe mental disorder. Two hours after an ECT session we found a statistically significant decrease of BDNF plasma levels (p=0.007). We did not find significant acute effects on NGF plasma levels or receptors expression in PBMCs. We found a significant inverse correlation between the time of convulsion and BDNF plasma levels decrease (r=-0.041, p=0.024). We have identified a decrease in BDNF plasma levels after 2h of a single ECT session. These results indicate the interest for future research in the role of neurotrophins in the response and safety of ECT

Short-term exposure to carbamazepine causes oxidative stress on common carp (Cyprinus carpio)

Artículo científico en revista indizadaThe aim of this research was to determine the bioconcentration factor and if subacute exposure to carbama- zepine (2 mg L−1) modifies the oxidative state of liver, gills and brain of Cyprinus carpio. This was measured through the following biomarkers: hydroperoxide and protein carbonyl content, lipid peroxidation degree, as well as superoxide dismutase, catalase and glutathione peroxidase activity. Carbamazepine concentration in carp’s tissue was also determined by liquid chromatography with a diode arrangement detector. An increase in lipid peroxidation degree, hydroperoxide and protein carbonyl content, and a decrease in the activity of the antioxidant enzymes (P < 0.05) with respect to control was observed. Also, there is an increase in the con- centration of carbamazepina present in the organs with respect to the water in the system, which denotes bioconcentration of the drug. In conclusion, carbamazepine is bioconcentrated and produces oxidative stress on the common carp (C. carpio).Secretaría de Investigación y Posgrado del Instituto Politécnico Nacional (SIP-IPN 20170919)

Deciding case by case on family presence in the emergency care service

Objective: To understand how physicians and nurses experience and perceive the presence of families in the emergency care service. Methods: This was a qualitative study that used symbolic interactionism as a theoretical reference, and grounded theory as a methodological reference. Twenty professionals participated – equally representing physicians and nurses - working in two emergency rooms located in the south of Brazil. Data were collected between October of 2016 and February of 2017, by means of interviews. Results: The existence of a social culture of family exclusion was identifi ed, widely diffused and practiced by professionals. However, families sometimes remain with their loved ones in the emergency room, since professionals analyze and decide “case by case”, considering different aspects throughout the care process. Conclusion: Multiple aspects are related in determining family presence during emergency care for physicians and nurses. Thus, a single directive on the presence of the family is not prudent. In fact, it is suggested that each health unit develop its protocols, considering local particularities.Objetivo: Compreender como médicos e enfermeiros vivenciam e percebem a presença da família no serviço de atendimento emergencial. Métodos: Estudo qualitativo que utilizou o Interacionismo Simbólico como referencial teórico e a Teoria Fundamentada nos Dados como referencial metodológico. Participaram 20 profi ssionais – divididos equitativamente entre médicos e enfermeiros – que atuavam em duas Salas de Emergência localizadas no Sul do Brasil. Os dados foram coletados entre outubro de 2016 e fevereiro de 2017, por meio de entrevistas. Resultados: Identifi cou-se a existência de uma cultura social de exclusão familiar, amplamente difundida e praticada pelos profi ssionais. Contudo, às vezes, as famílias permanecem com seus entes queridos na Sala de Emergência, visto que os profi ssionais analisam e decidem “caso a caso”, considerando diferentes aspectos ao longo do processo assistencial. Conclusão: Para médicos e enfermeiros múltiplos aspectos estão relacionados na determinação da presença familiar durante o atendimento emergencial. Assim, não é aconselhável uma diretiva única para a presença da família. Em realidade, sugere-se que cada unidade de saúde elabore seus protocolos considerando as particularidades locais.Objetivo: Comprender cómo médicos y enfermeros experimentan y perciben la presencia familiar en el servicio de atención de urgencias. Métodos: Estudio cualitativo, aplicando el Interaccionismo Simbólico como referencial teórico, y la Teoría Fundamentada en los Datos como referencial metodológico. Participaron 20 profesionales –equitativamente divididos entre médicos y enfermeros– actuantes en dos Servicios de Urgencias del Sur de Brasil. Datos recolectados de octubre 2016 a febrero 2017 mediante entrevistas. Resultados: Se identifi có la existencia de una cultura social de exclusión familiar, ampliamente difundida y practicada por los profesionales. Igualmente, a veces, las familias permanecen con sus seres queridos en el Servicio de Urgencias, dado que los profesionales analizan y deciden “caso por caso”, considerando diferentes aspectos a lo largo del proceso de atención. Conclusión: Para médicos y enfermeros, múltiples aspectos se relacionan con la determinación de la presencia familiar durante la atención de urgencia. Por ello, no es aconsejable una directiva única sobre presencia familiar. En realidad, se sugiere que cada unidad de salud elabore sus protocolos considerando sus propias características

Biochemical and structural characterization of a novel arginine kinase from the spider <i>Polybetes pythagoricus</i>

Energy buffering systems are key for homeostasis during variations in energy supply. Spiders are the most important predators for insects and therefore key in terrestrial ecosystems. From biomedical interest, spiders are important for their venoms and as a source of potent allergens, such as arginine kinase (AK, EC 2.7.3.3). AK is an enzyme crucial for energy metabolism, keeping the pool of phosphagens in invertebrates, and also an allergen for humans. In this work, we studied AK from the Argentininan spider Polybetes pythagoricus (PpAK), from its complementary DNA to the crystal structure. The PpAK cDNA from muscle was cloned, and it is comprised of 1068 nucleotides that encode a 384-amino acids protein, similar to other invertebrate AKs. The apparent Michaelis-Menten kinetic constant (Km) was 1.7 mM with a kcat of 75 s-1. Two crystal structures are presented, the apoPvAK and PpAK bound to arginine, both in the open conformation with the active site lid (residues 310-320) completely disordered. The guanidino group binding site in the apo structure appears to be organized to accept the arginine substrate. Finally, these results contribute to knowledge of mechanistic details of the function of arginine kinase.Instituto de Investigaciones Bioquímicas de La Plat