RESUMO
OBJECTIVE: The purpose of this study was to assess knowledge and attitudes regarding end-of-life care (ELOC) among senior medical students at the University of Puerto Rico School of Medicine. METHODS: This was a cross-sectional study in which a questionnaire was administered to senior medical students from February through March 2017. The questionnaire included a knowledge and an attitudinal scale, and socio-demographic information. RESULTS: Eighty-one students with a mean age of 26 years participated. The majority were female (60.5%; n = 49) and most participants (81.5%; n = 63) correctly answered more than 70% of the questions on the knowledge scale. However, less than half (45.7%; n = 37) perceived that they had the knowledge necessary for EOLC. More male than female students (68.3% and 30.6%, respectively) felt that they were adequately prepared for working with patients requiring EOLC, a difference that was significant (P < .05). Most participants (81.0%; n = 66) had experienced the loss (due to death) of a significant person, and 66.0% (n = 53) felt that they had benefited from their experiences regarding being able to handle death. CONCLUSION: The study shows that participants had adequate knowledge about and positive attitudes toward EOLC but believed that they were lacking in knowledge, especially female students. These findings suggest the need to design and implement strategies to develop and strengthen self-efficacy in medical students regarding management of patients at the end of life.
Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Estudantes de Medicina/psicologia , Assistência Terminal/psicologia , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Porto Rico , Faculdades de Medicina , Inquéritos e QuestionáriosRESUMO
We investigated for the first time the expression of melanoma cell adhesion molecule (MCAM) and its involvement in the differentiation of 3T3-L1 fibroblasts to adipocytes. We found that MCAM mRNA increased subsequent to the activation of the master regulator of adipogenesis, PPARγ, and this increase was maintained in the mature adipocytes. On the other hand, MCAM knockdown impaired differentiation and induction of PPARγ as well as expression of genes activated by PPARγ. However, events that precede and are necessary for early PPARγ activation, such as C/EBPß induction, ß-catenin downregulation, and ERK activation, were not affected in the MCAM knockdown cells. In keeping with this, the increase in PPARγ mRNA that precedes MCAM induction was not altered in the knockdown cells. In conclusion, our findings suggest that MCAM is a gene upregulated and involved in maintaining PPARγ induction in the late but not in the early stages of 3T3-L1 fibroblasts adipogenesis.
Assuntos
Adipócitos/metabolismo , Adipogenia , Diferenciação Celular , Fibroblastos/metabolismo , Regulação da Expressão Gênica , PPAR gama/biossíntese , Células 3T3-L1 , Adipócitos/citologia , Animais , Antígeno CD146/genética , Antígeno CD146/metabolismo , Fibroblastos/citologia , Técnicas de Silenciamento de Genes , Camundongos , PPAR gama/genéticaRESUMO
Glyphosate-based herbicides (GF) are extensively used for weed control. Thus, it is important to investigate their putative toxic effects. We have reported that GF at subagriculture concentrations inhibits proliferation and differentiation to adipocytes of 3T3-L1 fibroblasts. In this investigation, we evaluated the effect of GF on genes upregulated during adipogenesis. GF was able to inhibit the induction of PPAR gamma, the master gene in adipogenesis but not C/EBP beta, which precedes PPAR gamma activation. GF also inhibited differentiation and proliferation of another model of preadipocyte: mouse embryonic fibroblasts. In exponentially growing 3T3-L1 cells, GF increased lipid peroxidation and the activity of the antioxidant enzyme, superoxide dismutase. We also found that proliferation was inhibited with lower concentrations of GF when time of exposure was extended. Thus, GF was able to inhibit proliferation and differentiation of preadipocytes and to induce oxidative stress, which is indicative of its ability to alter cellular physiology.
Assuntos
Adipócitos/efeitos dos fármacos , Adipogenia/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Glicina/análogos & derivados , Herbicidas/farmacologia , PPAR gama/genética , Células 3T3-L1 , Adipócitos/citologia , Adipócitos/metabolismo , Animais , Proteína beta Intensificadora de Ligação a CCAAT/genética , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Embrião de Mamíferos , Fibroblastos/citologia , Fibroblastos/metabolismo , Regulação da Expressão Gênica , Glicina/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Camundongos , Estresse Oxidativo , PPAR gama/antagonistas & inibidores , PPAR gama/metabolismo , Cultura Primária de Células , Transdução de Sinais , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , GlifosatoRESUMO
Heavy metals contamination has become an important risk factor for public health and the environment. Chromium is a frequent industrial contaminant and is also used in orthopaedic joint replacements made from cobalt-chromium-alloy. Since hexavalent chromium (Cr(VI)) was reported as genotoxic and carcinogenic in different mammals, to further evaluate its cytotoxicity, we investigated the effect of this heavy metal in the proliferation and differentiation to adipocytes of 3T3-L1 fibroblasts. These cells, after the addition of a mixture containing insulin, dexamethasone and methylisobutylxanthine, first proliferate, a process known as mitotic clonal expansion (MCE), and then differentiate to adipocytes. In this differentiation process a key transcription factor is induced: peroxisome proliferator-activated receptor gamma (PPAR gamma). We found that treatment of 3T3-L1 fibroblasts with potassium chromate inhibited proliferation in exponentially growing cells and MCE as well as differentiation. A decrease in PPAR gamma content, evaluated by western blot and immunofluorescence, was found in cells differentiated in the presence of chromium. On the other hand, after inhibition of differentiation with chromium, when the metal was removed, differentiation was recovered, which indicates that this may be a reversible effect. We also found an increase in the number of micronucleated cells after treatment with Cr(VI) which is associated with genotoxic effects. According to our results, Cr(VI) is able to inhibit proliferation and differentiation to adipocytes of 3T3-L1 fibroblasts and to increase micronucleated cells, which are all indicative of alterations in cellular physiology and therefore, contributes to further elucidate the cytotoxic effects of this heavy metal.
Assuntos
Adipócitos/citologia , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Cromo/toxicidade , Fibroblastos/efeitos dos fármacos , Células 3T3-L1 , Adipócitos/efeitos dos fármacos , Animais , Poluentes Ambientais/toxicidade , Fibroblastos/citologia , Fibroblastos/fisiologia , CamundongosRESUMO
Glyphosate-based herbicides are extensively used for weed control all over the world. Therefore, it is important to investigate the putative toxic effects of these formulations which include not only glyphosate itself but also surfactants that may also be toxic. 3T3-L1 fibroblasts are a useful tool to study adipocyte differentiation, this cell line can be induced to differentiate by addition of a differentiation mixture containing insulin, dexamethasone and 3-isobutyl-1-methylxanthine. We used this cell line to investigate the effect of a commercial formulation of glyphosate (GF) on proliferation, survival and differentiation. It was found that treatment of exponentially growing cells with GF for 48h inhibited proliferation in a dose-dependent manner. In addition, treatment with GF dilution 1:2000 during 24 or 48h inhibited proliferation and increased cell death, as evaluated by trypan blue-exclusion, in a time-dependent manner. We showed that treatment of 3T3-L1 fibroblasts with GF increased caspase-3 like activity and annexin-V positive cells as evaluated by flow cytometric analysis, which are both indicative of induction of apoptosis. It was also found that after the removal of GF, remaining cells were able to restore proliferation. On the other hand, GF treatment severely inhibited the differentiation of 3T3-L1 fibroblasts to adipocytes. According to our results, a glyphosate-based herbicide inhibits proliferation and differentiation in this mammalian cell line and induces apoptosis suggesting GF-mediated cellular damage. Thus, GF is a potential risk factor for human health and the environment.
Assuntos
Adipócitos/citologia , Fibroblastos/efeitos dos fármacos , Glicina/análogos & derivados , Herbicidas/toxicidade , Células 3T3 , Animais , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Fibroblastos/citologia , Glicina/toxicidade , Camundongos , GlifosatoRESUMO
Adipogenesis is stimulated in 3T3-L1 fibroblast by a combination of insulin, dexamethasone, and methylisobutylxanthine (MIX). Mitotic clonal expansion (MCE) precedes differentiation of 3T3-L1 fibroblast to adipocytes. MIX increases cAMP content, which is the activator of protein kinase A (PKA). However, PKA-independent cAMP signaling has also been described. In this paper, it was found that H89, an inhibitor of PKA, was able to block MCE but not differentiation of 3T3-L1 fibroblast. Consistently, MCE did not occur in the absence of MIX in the differentiation mixture but was recovered by overexpression of a catalytic subunit of PKA. In addition, the transfection of 3T3-L1 fibroblast with a dominant-negative mutant of PKA inhibited MCE. On the other hand, differentiation of 3T3-L1 fibroblast to adipocytes did not occur when MIX was not present in the differentiation mixture and it could not be recovered by overexpression of a catalytic subunit of PKA. Differentiation was restored by addition of either dibutyryl-cAMP (db-cAMP) or 8 CPT-2 Me-cAMP. The latter activates cAMP-EPAC but not PKA signaling. These results indicate that cAMP-PKA-independent signaling, is required for 3T3-L1 fibroblasts differentiation to adipocytes and MIX signaling through cAMP-PKA is necessary for MCE, although MCE is not essential for adipogenesis.
Assuntos
Células 3T3-L1 , Diferenciação Celular/fisiologia , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , AMP Cíclico/fisiologia , Fibroblastos/fisiologia , 1-Metil-3-Isobutilxantina/farmacologia , Adipogenia/efeitos dos fármacos , Adipogenia/fisiologia , Animais , Diferenciação Celular/efeitos dos fármacos , AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/antagonistas & inibidores , Dexametasona/farmacologia , Fibroblastos/efeitos dos fármacos , Insulina/farmacologia , Isoquinolinas/farmacologia , Camundongos , Mitose/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Sulfonamidas/farmacologia , Teofilina/análogos & derivados , Teofilina/farmacologiaRESUMO
Different cytochromes P450 are involved in steroid biosynthesis. These cytochromes have heme as the prosthetic group. We previously reported that ACTH, an activator of glucocorticoid biosynthesis in adrenal, requires heme biosynthesis for a maximal response. In the present study, we investigated the effect of ACTH, and the effect of two activators of the adrenal mineralocorticoid synthesis, endothelin-1 and low sodium diet on 5-aminolevulinate-synthase (ALA-s) mRNA. ALA-s is the rate-limiting enzyme in heme biosynthesis. It was found that infusion of rats with ACTH for 1 h caused an increase of adrenal ALA-s mRNA and activity accompanied by an increase in plasma corticosterone. CYP21, a cytochrome involved in the synthesis of both corticosterone and aldosterone, was not modified at the RNA level in adrenal glands by 1 h of ACTH infusion. Consistently, infusion of endothelin-1 for 1 h increased ALA-s mRNA and aldosterone content in adrenal gland without modifying CYP21 mRNA levels. To study if ALA-s is also regulated by the main physiological stimuli that increase adrenal mineralocorticoid secretion, we fed rats with low salt diet for 2 or 15 days. Low salt diet treatment increased adrenal gland ALA-s mRNA levels. On the other hand, the rapid stimulation of ALA-s mRNA by ACTH which acts through cyclic AMP was confirmed in H295R human adrenocortical cells, the only human adrenal cell line that has a steroid secretion pattern and regulation similar to primary cultures of adrenal cells. Our findings suggest that the acute activation of adrenal steroidogenic cytochromes by trophic hormones involves an increase in heme biosynthesis which will favor the production of active cytochromes.