RESUMEN
Vibrio parahaemolyticus is a moderately halophilic foodborne pathogen that is mainly distributed in marine and freshwater environments. The transition of V. parahaemolyticus between aquatic ecosystems and hosts is essential for infection. Both freshwater and host environments have low salinity. In this study, we sought to further investigate the effects of low salinity (0.5% NaCl) on the fitness and virulence of V. parahaemolyticus. We found that V. parahaemolyticus could survive in Luria-Bertani (LB) and M9 mediums with different NaCl concentrations, except for the M9 medium containing 9% NaCl. Our results further showed that V. parahaemolyticus cultured in M9 medium with 0.5% NaCl had a higher cell density than that cultured at other NaCl concentrations when it entered the stationary phase. Therefore, we compared the transcriptomes of V. parahaemolyticus wild type (WT) cultured in an M9 medium with 0.5% and 3% NaCl at the stationary phase using RNA-seq. A total of 658 genes were significantly differentially expressed in the M9 medium with 0.5% NaCl, including regulators, osmotic adaptive responses (compatible solute synthesis systems, transporters, and outer membrane proteins), and virulence factors (T3SS1 and T6SS1). Furthermore, a low salinity concentration in the M9 medium induced the expression of T3SS1 to mediate the cytotoxicity of V. parahaemolyticus to HeLa cells. Similarly, low salinity could also induce the secretion of the T3SS2 translocon protein VPA1361. These factors may result in the high pathogenicity of V. parahaemolyticus in low-salinity environments. Taken together, these results suggest that low salinity (0.5% NaCl) could affect gene expression to mediate fitness and virulence, which may contribute to the transition of V. parahaemolyticus between aquatic ecosystems and the host.
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Vibrio parahaemolyticus , Humanos , Vibrio parahaemolyticus/metabolismo , Sistemas de Secreción Tipo III/metabolismo , Cloruro de Sodio/farmacología , Cloruro de Sodio/metabolismo , Células HeLa , Presión Osmótica , Ecosistema , Perfilación de la Expresión Génica , Proteínas Bacterianas/metabolismoRESUMEN
Zearalenone (ZEA) is one of the most major food contaminants in cereal crops worldwide, risking health of both livestock and humans. This study aimed to assess the cytotoxicity and the underlying mechanism of ZEA on thymic epithelial cells. By using proteomics analysis, we identified 596 differentially expressed proteins in MTEC1 cells upon zearalenone exposure, of which 245 were upregulated and 351 were downregulated. Gene ontology (GO) analysis suggested that differentially expressed proteins were participated in protein synthesis, oxidative phosphorylation, and ATP binding. KEGG pathway enrichment analysis showed that differentially expressed proteins were mainly related to mitochndrial metabolism, such as citrate cycle (TCA cycle) and oxidative phosphorylation. We demonstrated that ZEA treatment was able to increase the intracellular reactive oxygen species (ROS) level, to decrease ΔΨm, ATP level, and the copy number of mtDNA, leading to necrotic cell death. Moreover, we showed that ZEA treatment inhibited cell proliferation and induced G2/M phase arrest by downregulation of proliferation-associated proteins ERK, p-ERK, CDK1, and p-CHK1. Taken together, we found that the toxicity of ZEA on thymic epithelial cells is mainly caused by the inhibition of mitochondrial dysfunction and cell proliferation. Our study might open new avenues for treatment strategies.
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Zearalenona , Adenosina Trifosfato/metabolismo , Animales , Células Epiteliales/metabolismo , Ratones , Proteómica , Especies Reactivas de Oxígeno/metabolismo , Zearalenona/toxicidadRESUMEN
Zearalenone (ZEA) was a mycotoxin biosynthesized by a variety of Fusarium fungi via a polypeptide pathway. ZEA has significant toxic reaction on immune cells. Thymic epithelial cells (TECs) as a crucial constituent of thymic stroma can provide unique microenvironment for thymocyte maturation, but the mechanism of ZEA affecting the TECs is poorly understood. The basic data about gene expression differences for the ZEA on thymic epithelial cell line 1 (MTEC1) will help us to elucidate this mechanism. Here, cell viability and proliferation assay and transcriptome sequencing on MTEC1 treated with ZEA were performed. 4188 differentially expressed genes (DEGs) between ZEA treated and control groups were identified, confirmed and analyzed. Our results showed that 10-50µg/ml ZEA significantly inhibited MTEC1 proliferation and arrested cell cycle at G2/M phase. Gene ontology and KEGG pathway analysis revealed that Chemokine, JAK-STAT and Toll-like receptor signaling pathway, were involved in the cell cycle pathway. 16 key genes involved in the cell cycle processes were validated and the results suggested that Mitotic catastrophe (MC) may take part in ZEA inhibition of METC1 cell proliferation. These data highlighted the importance of cell cycle pathway in MTEC1 treated with ZEA, and will contribute to get the molecular mechanisms of ZEA inhibition of MTEC1 cell proliferation.
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Proliferación Celular/efectos de los fármacos , Células Epiteliales/efectos de los fármacos , Timo/efectos de los fármacos , Transcripción Genética/efectos de los fármacos , Zearalenona/toxicidad , Animales , Técnicas de Cultivo de Célula , Ciclo Celular/efectos de los fármacos , Línea Celular , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Perfilación de la Expresión Génica , Secuenciación de Nucleótidos de Alto Rendimiento , Ratones , Timo/patologíaRESUMEN
The gender-biased thymus involution and the importance of microRNAs (miRNAs, miRs) expression in modulating the thymus development have been reported in many studies. However, how males and females differ in so many ways in thymus involution remains unclear. To address this question, we investigated the miRNA expression profiles in both untreated 3- and 12-month-old female and male mice thymuses. The results showed that 7 and 18 miRNAs were defined as the sex- and age-specific miRNAs, respectively. The expression of miR-181c-5p, miR-20b-5p, miR-98b-5p, miR-329-3p, miR-341-5p, and miR-2137 showed significant age-difference in mice thymus by quantitative polymerase chain reaction. High expression levels of miR-2137 were detected in mice thymic epithelial cells and gradually increased during the process of thymus aging. MiR-27b-3p and miR-378a-3p of the female-biased miRNAs were confirmed as the sex- and estrogen-responsive miRNAs in mice thymus in vivo. Their potential target genes and the pathway were identified by the online software. Possible regulation roles of sex- and age-specific miRNA expression during the process of thymus aging were discussed. Our results suggested that these miRNAs may be potential biomarkers for the study of sex- and age-specific thymus aging and involution.
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Envejecimiento/metabolismo , Regulación del Desarrollo de la Expresión Génica/fisiología , MicroARNs/metabolismo , Caracteres Sexuales , Timo/metabolismo , Animales , Femenino , Masculino , Ratones , Ratones Endogámicos BALB CRESUMEN
In view of the extensive use of nanoparticles in countless applications, a fast and effective method for assessing their potential adverse effects on the environment and human health is extremely important. At present, in vitro cell-based assays are the standard approach for screening chemicals for cytotoxicity because of their relative simplicity, sensitivity, and cost-effectiveness compared with animal studies. Regrettably, such cell-based viability assays encounter limitations when applied to determining the biological toxicity of nanomaterials, which often interact with assay components and produce unreliable outcomes. We have established a cell-impedance-based, label-free, real-time cell-monitoring platform suitable for use in a variety of mammalian cell lines that displays results as cell index values. In addition to this real-time screening platform, other traditional cytotoxicity assays were employed to validate cytotoxicity assessments. We suggest that the cell impedance measurement approach is effective and better suited to determining the cytotoxicity of nanomaterials for environmental safety screening. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1170-1182, 2017.
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Nanopartículas del Metal/toxicidad , Células A549 , Animales , Apoptosis/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Humanos , Ensayo de Materiales , Ratones , Células 3T3 NIH , Estrés Oxidativo , Tamaño de la PartículaRESUMEN
Chemotherapeutic agents can upregulate autophagy which contributes to the acquisition of chemoresistance and the recurrence of cancer. The involvement of hHR23A in chemoresistance is unknown. In this study, we provide evidence suggesting that hHR23A may regulate autophagy. Knockdown of hHR23A decreased cell growth and increased the resistance in A549 cells to the DNA-damaging agents, cisplatin and oxaliplatin. Measurement of EGFP-LC3 puncta (a marker of autophagy) revealed that autophagy was increased in hHR23A-depleted cells. This effect was augmented by exposure to cisplatin or oxaliplatin. In contrast, the overexpression of hHR23A reversed the levels of autophagy-related proteins to control levels in hHR23A-knockdown cells. Moreover, we observed direct interactions among hHR23A, Beclin 1, and LC3. Finally, 3-methyladenine (3-MA)-induced inhibition of autophagy was found to reverse the sensitivity of hHR23A-knockdown cells to the tested DNA-damaging agents. These results collectively indicated that hHR23A-depleted cells exhibit enhanced autophagy when treated with DNA-damaging agents, perhaps suggesting a basis for the involvement of hHR23A in the acquired chemoresistance of cancer cells. Our study thus reveals a previously unrecognized autophagic function for hHR23A and suggests that it could be a potential therapeutic target for chemosensitizing resistant cancer cells.
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Autofagia/efectos de los fármacos , Cisplatino/farmacología , Enzimas Reparadoras del ADN/metabolismo , Proteínas de Unión al ADN/metabolismo , Compuestos Organoplatinos/farmacología , Células A549 , Adenina/análogos & derivados , Adenina/farmacología , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Apoptosis/genética , Autofagia/genética , Beclina-1/metabolismo , Proliferación Celular/efectos de los fármacos , Proliferación Celular/genética , Enzimas Reparadoras del ADN/genética , Proteínas de Unión al ADN/genética , Resistencia a Antineoplásicos/efectos de los fármacos , Resistencia a Antineoplásicos/genética , Citometría de Flujo , Humanos , Immunoblotting , Microscopía Confocal , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/metabolismo , Oxaliplatino , Unión Proteica , Interferencia de ARNRESUMEN
The expression profiles of miRNAs in thymus tissues from mice of different age have been demonstrated in our previous study. After an integrated analysis of the miRNA expression profiles, we demonstrated that the expression of miR-181a-5p was significantly decreased in thymic epithelial cells (TECs) from 10- to 19-month-old mice when compared with that in TECs from 1-month-old mice by quantitative reverse transcriptase polymerase chain reaction. We hypothesized that miR-181a-5p in TECs might be associated with the age-related thymus involution through regulating some genes or signaling pathway. To test this hypothesis, the mouse medullary thymic epithelial cells (MTEC1) were used. Transfection with miR-181a-5p mimic promoted the proliferation of MTEC1 cells, but did not affect apoptosis. The effect was reversed when the expression of miR-181a-5p was suppressed in MTEC1 cells. Furthermore, the transforming growth factor beta receptor I (Tgfbr1) was confirmed as a direct target of miR-181a-5p by luciferase assay. Moreover, it was found that overexpression of miR-181a-5p down-regulated the phosphorylation of Smad3 and blocked the activation of the transforming growth factor beta signaling. Nevertheless, an inversely correlation was observed between the expression of Tgfbr1 and miR-181a-5p in TECs derived from mice of different age. Collectively, we provide evidence that miR-181a-5p may be an important endogenous regulator in the proliferation of TECs, and the expression levels of miR-181a-5p in TECs may be associated with the age-related thymus involution.
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MicroARNs/genética , Timo/citología , Timo/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Envejecimiento/genética , Envejecimiento/metabolismo , Animales , Apoptosis/genética , Apoptosis/fisiología , Línea Celular , Proliferación Celular/genética , Proliferación Celular/fisiología , Supervivencia Celular/genética , Supervivencia Celular/fisiología , Regulación hacia Abajo , Células Epiteliales/metabolismo , Ratones , Ratones Endogámicos BALB C , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Receptor Tipo I de Factor de Crecimiento Transformador beta , Receptores de Factores de Crecimiento Transformadores beta/genética , Receptores de Factores de Crecimiento Transformadores beta/metabolismo , Transducción de Señal/genética , Proteína smad3/genética , Proteína smad3/metabolismo , TranscriptomaRESUMEN
MicroRNAs are highly conserved non-coding small RNAs participating in almost all kinds of biological activities. MiR-181a has been reported to be involved in the differentiation of porcine primary preadipocytes, but the profound effect of miR-181a-5p on 3T3-L1 adipocyte differentiation and proliferation is still unclear. In this study, we found that supplementation of miR-181a-5p in 3T3-L1 cells significantly promoted the adipogenesis and inhibited cell proliferation with increased expression of adipogenic marker genes including peroxisome proliferator-activated receptor gamma (Pparγ), CCAAT/enhancer-binding protein alpha (C/ebpα), fatty acid-binding protein 4 (Fabp4), and Adiponectin, accompanied by an accumulation of lipid droplet, an increase of triglyceride content, and a decrease of cell proliferation. Furthermore, by using the luciferase assay, Smad7 and Tcf7l2, two important members of transforming growth factor-ß (TGFß) and Wnt signaling pathway, were proven to be the direct target genes of miR-181a-5p. Moreover, supplementation of miR-181a-5p in 3T3-L1 cells altered the expressions of proteins involved in the TGFß signaling pathway, such as TGFBR1, p-SMAD3, SMAD4, c-MYC, and p15. Taken together, these results indicate that miR-181a-5p promotes 3T3-L1 preadipocyte differentiation and adipogenesis through regulating TGFß/Smad and Wnt signaling pathway by directly targeting Smad7 and Tcf7l2.
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Adipogénesis/genética , MicroARNs/fisiología , Proteína smad7/genética , Proteína 1 Similar al Factor de Transcripción 7/genética , Células 3T3-L1 , Adipocitos/citología , Animales , Diferenciación Celular/fisiología , RatonesRESUMEN
MiR-195 has been implicated in inhibiting cell proliferation in different types of tumors. Whether it contributes to the process of thymic epithelial cells (TECs) proliferation remains unclear. In this study, we found that miR-195a-5p was highly up-regulated in the TECs isolated from the aging mice. Further experiments showed that miR-195a-5p mimic transfection inhibited the proliferation of mouse medullary thymic epithelial cell line 1 (MTEC1), whereas the transfection of miR-195a-5p inhibitor in MTEC1 had the opposite effect. In addition, miR-195a-5p had no obvious effect on MTEC1 apoptosis. Furthermore, Smad7, a negative regulator of transforming growth factor ß pathway, was confirmed as a direct target of miR-195a-5p by luciferase assays. Taken together, our results indicate that miR-195a-5p inhibits MTEC1 proliferation, at least in part, via down-regulation of Smad7.
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Proliferación Celular/fisiología , MicroARNs/fisiología , Proteína smad7/metabolismo , Timo/citología , Animales , Apoptosis , Células Epiteliales/metabolismo , Ratones , Ratones Endogámicos BALB C , MicroARNs/metabolismo , Timo/metabolismoRESUMEN
Previous evidence has indicated that the microRNA-125b (miR-125b) family plays important roles in the regulation of cancer cell growth, development, differentiation, and apoptosis. However, whether they contribute to the process of adipocyte differentiation remains unclear. In the present study, we revealed that the expression level of miR-125b-5p, a member of miR-125b family, was dramatically up-regulated during differentiation of 3T3-L1 preadipocyte into mature adipocyte. Supplement of miR-125b-5p into 3T3-L1 cells promoted adipogenic differentiation as evidenced by increased lipid droplets and mRNA levels of adipocyte-specific molecular markers, including peroxisome proliferators-activated receptor γ, CCAAT/enhancer-binding protein α, fatty acid-binding protein 4, and lipoprotein lipase, and by triglyceride accumulation. CCK-8 assay showed that miR-125b-5p supplementation significantly inhibited cell proliferation. Flow cytometry analysis showed that miR-125b-5p impaired G1/S phase transition as well as the mRNA and protein expression of G1/S-related genes, such as Cyclin D2, Cyclin D3, and CDK4. Nevertheless, it had no effect on apoptosis. Additionally, by target gene prediction, we demonstrated that smad4 may be a potential target of miR-125b-5p in mouse 3T3-L1 preadipocytes, accounting for some of miR-125b-5p's functions. Taken together, these data indicated that miR-125b-5p may serve as an important positive regulator in adipocyte differentiation, at least partially through down-regulating smad4.
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Tejido Adiposo/citología , Diferenciación Celular , Proliferación Celular , MicroARNs/fisiología , Células 3T3-L1 , Animales , RatonesRESUMEN
INTRODUCTION: Work-related musculoskeletal disorders (WMSDs) are disorders of the musculoskeletal system that have the highest prevalence among workers worldwide. Workers in gas stations usually work in poor ergonomic working conditions, including prolonged standing and repetitive posturing. OBJECTIVE: The study aimed to investigate the prevalence of WMSDs and fatigue and to identify the predictors of WMSDs among gas station workers. DESIGN: The present study was a cross-sectional study. SETTING AND PARTICIPANTS: 2962 gas station workers from an oil and gas company in China, with ages ranging from 17 to 75 years old, 55.47% female. RESULTS: The prevalence of WMSDs within the 12 months prior to the study was 73.23%, with the highest prevalence in the neck, shoulders, ankles and feet. Furthermore, a correlation was observed between fatigue, stress and WMSDs. Fatigue and job role were the strongest predictors of WMSDs, with an OR range of 2.211-3.413. CONCLUSIONS: This research identified the detrimental impact of WMSDs and fatigue on gas station workers, indicating the critical need for interventions to reduce WMSDs and relieve fatigue.
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Fatiga , Enfermedades Musculoesqueléticas , Enfermedades Profesionales , Humanos , Estudios Transversales , Femenino , Adulto , China/epidemiología , Masculino , Persona de Mediana Edad , Fatiga/epidemiología , Enfermedades Profesionales/epidemiología , Enfermedades Profesionales/etiología , Adulto Joven , Enfermedades Musculoesqueléticas/epidemiología , Enfermedades Musculoesqueléticas/etiología , Prevalencia , Adolescente , Anciano , Estrés Laboral/epidemiología , Industria del Petróleo y GasRESUMEN
Logistics personnel in Chinese universities are facing unbalanced costs and benefit from overloaded work with minimum wages, which impede school development and their well-being. However, the logistics staff population has been neglected in past investigations pertaining to psychological health conditions. The present study aimed to examine the positive well-being, work-related rumination, and work engagement of logistics staff, their correlations, and the factors affecting well-being in 282 Chinese university logistics staff via the Smith Well-being Questionnaire, the Work-Related Rumination Questionnaire, and the Utrecht Work Engagement Scale. The results indicated low levels of well-being and high levels of work-related rumination and work engagement among Chinese university logistics staff. The presence of positive attitudes towards life and work and high levels of work engagement predicts enhanced well-being, while the presence of negative characteristics and work-related rumination predicts decreased well-being. In situations where the working hours and work duties are challenging to change, universities can regularly schedule psychological counselling sessions for logistics staff to improve their well-being.
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Tech giants are large, well-known internet and technology companies. Employees of such companies are generally expected to work fast and for long periods of time, causing them to experience high occupational fatigue. The relationship between occupational fatigue and well-being is complex. Furthermore, in the context of the workplace, unhealthy eating behaviour may be used as a mechanism to cope with fatigue and stress. This study explored the relationship between occupational fatigue, well-being and unhealthy eating behaviour within this specific professional population. Study 1 used qualitative research methods, in which in-depth interviews were conducted with staff working at 13 tech giants in Shenzhen, China (N = 50). The findings revealed that work-related stress and occupational fatigue are common among employees working for tech giants. Additionally, factors such as unhealthy eating behaviour, workload, working hours and workplace interpersonal relationships were found to influence occupational well-being. Study 2 involved a cross-sessional survey of 237 employees of tech giants. The results indicated that occupational fatigue negatively impacts occupational well-being and that unhealthy eating behaviours play a moderating role between occupational fatigue and occupational well-being. These findings highlight the significance of adopting appropriate measures to improve the situation and cope with the effects of occupational fatigue by managing unhealthy eating behaviours.
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Immunotherapy targeting immune checkpoints (ICPs), such as programmed death-ligand-1 (PD-L1), is used as a treatment option for advanced or metastatic non-small cell lung cancer (NSCLC). However, overall response rate to anti-PD-L1 treatment is limited due to antigen heterogeneity and the immune-suppressive tumor microenvironment. Human leukocyte antigen-G (HLA-G), an ICP as well as a neoexpressed tumor-associated antigen, is previously demonstrated to be a beneficial target in combination with anti-PD-L1. In this study, a nanobody-based trispecific T cell engager (Nb-TriTE) is developed, capable of simultaneously binding to T cells, macrophages, and cancer cells while redirecting T cells toward tumor cells expressing PD-L1- and/or HLA-G. Nb-TriTE shows broad spectrum anti-tumor effects in vitro by augmenting cytotoxicity mediated by human peripheral blood mononuclear cells (PBMCs). In a humanized immunodeficient murine NSCLC model, Nb-TriTE exhibits superior anti-cancer potency compared to monoclonal antibodies and bispecific T cell engagers. Nb-TriTE, at the dose with pharmacoactivity, does not induce additional enhancement of circulating cytokines secretion from PMBCs. Nb-TriTE effectively prolongs the survival of mice without obvious adverse events. In conclusion, this study introduces an innovative therapeutic approach to address the challenges of immunotherapy and the tumor microenvironment in NSCLC through utilizing the dual ICP-targeting Nb-TriTE.
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BACKGROUND: Occupational health factors such as shift work, sleep, fatigue, and work environment jeopardise the health and safety of gas station workers. This calls for new research to investigate how the working environment and characteristics impact the occupational health of workers at gas stations. However, minimal research has been conducted in this field, especially those involving psychological and behavioural factors, occupational stress, and so forth. OBJECTIVE: This review was performed to investigate the present condition of the occupational risk of gas station workers in this safety-critical position. METHODS: Five databases (Web of Science, ScienceDirect, PubMed, Google Scholar, and PsycINFO) were searched for relevant peer-reviewed studies. Results were selected according to these criteria: studies on fatigue, shift work, sleep, and physical and mental health of gas station employees; published on or before November 11, 2021; papers in English. RESULTS: Twenty studies were considered for the final analysis. The results showed that shift work at gas stations leads to psychological and physiological problems. The psychological consequences included anxiety, stress, and depression, while the physiological consequences included biochemical changes and lifestyle consequences. CONCLUSION: Shift work and the specific working environment of gas station employees adversely affect their sleep, stress levels, physical and mental health, and turnover intention. This systematic review allowed us to consider the occupational risk factors that can lead to sickness or accidents and contribute to reducing these risk factors. Realistic countermeasures ought to be established and interventions must be explored to mitigate risks to life, property, and the environment in operating gas stations.
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Salud Laboral , Estrés Laboral , Humanos , Salud Mental , Sueño , Fatiga/etiologíaRESUMEN
Spigelian hernias are a rare lateral ventral abdominal hernia that carry a high risk of strangulation due to their smaller sizes, and require surgical intervention. In more complex cases involving an anticoagulated patient, perioperative management of anticoagulation must be monitored and reviewed to avoid potential pitfalls. We present an 81-year-old woman who presented with right groin pain, and was requiring warfarin anticoagulation due to her cardiac history. The spigelian hernia was diagnosed and reduced laparoscopically, and the defect was repaired and reinforced by mesh. However, the patient suffered from catastrophic complications postoperatively related to her anticoagulation management. Spigelian hernias require surgical interventions. However, in an anticoagulated patient with significant comorbidities, perioperative anticoagulation needs to be closely monitored to balance the risk of thromboembolic disease with acceptable postoperative bleeding risks.
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Anticoagulantes/efectos adversos , Enoxaparina/efectos adversos , Hematoma/diagnóstico , Hernia Ventral/cirugía , Hemorragia Posoperatoria/diagnóstico , Anciano de 80 o más Años , Diagnóstico Diferencial , Resultado Fatal , Femenino , Hematoma/inducido químicamente , Hernia Ventral/complicaciones , Humanos , Laparoscopía , Dolor/etiología , Hemorragia Posoperatoria/inducido químicamente , Mallas QuirúrgicasRESUMEN
Among other functions, the Chk1 protein plays an essential role in coordinating the cellular stress response by determining cell cycle arrest. The levels of Chk1 expression and activity are critical for its functions, especially in cell cycle progression, genomic integrity, cell viability and tissue development. Chk1 protein expression should therefore be tightly controlled both during normal growth and under stress situations. However, it is still unknown how Chk1 protein levels are regulated during normal cell cycle progression. In this study, we show that the effect of hHR23A on Chk1 protein turnover could impact the cell cycle progression observed in hHR23A-knockdown cells. Our results reveal that hHR23A associates with Chk1 through its UBA domains, and that knockdown of hHR23A increases and stabilizes the protein level of Chk1 and its phosphorylation at S347. Knockdown of hHR23A results in proliferation defects and S-phase accumulation. DNA damage reduces the interaction between Chk1 and hHR23A, releasing Chk1 from hHR23A and enhancing S-phase accumulation. Based on these novel findings, we propose that hHR23A acts as a carrier to promote Chk1 degradation through the Ubiquitin Proteasome System. These results strengthen the model in which DNA damage induces Chk1 phosphorylation on chromatin followed by releasing phospho-Chk1 from the chromatin into soluble nucleus and the cytoplasm where Chk1 activates the cell cycle checkpoints; and finally, Chk1 is degraded and checkpoint signaling is terminated.
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Puntos de Control del Ciclo Celular/genética , Enzimas Reparadoras del ADN/genética , Proteínas de Unión al ADN/genética , Proteínas Quinasas/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Proteínas de Ciclo Celular/metabolismo , Línea Celular Tumoral , Proliferación Celular/genética , Supervivencia Celular , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Daño del ADN/genética , Replicación del ADN/genética , Humanos , Fosforilación/genética , Proteínas Quinasas/genética , Estructura Terciaria de Proteína , Interferencia de ARN , ARN Interferente Pequeño/genética , Fase S/genética , Transducción de SeñalRESUMEN
Bear bile was used as a traditional medicine or tonic in East Asia, and ursodeoxycholic acid (UDCA) is the most important compound in bear bile. Further, synthetic UDCA is also used in modern medicine and nutrition; therefore, its further functional effects warrant research, in vitro methods could be used for the fundamental research of its anticancer effects. In this study, the apoptotic effects of UDCA in human oral squamous carcinoma HSC-3 cells through the activation of caspases were observed by the experimental methods of MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) assay, DAPI (4',6-diamidino-2-phenylindole) staining, flow cytometry analysis, RT-PCR (reverse transcription-polymerase chain reaction) assay and Western blot assay after HSC-3 cells were treated by different concentrations of UDCA. With 0 to 400 µg/mL UDCA treatment, UDCA had strong growth inhibitory effects in HSC-3 cells, but had almost no effect in HOK normal oral cells. At concentrations of 100, 200 and 400 µg/mL, UDCA could induce apoptosis compared to untreated control HSC-3 cells. Treatment of 400 µg/mL UDCA could induce more apoptotic cancer cells than 100 and 200 µg/mL treatment; the sub-G1 DNA content of 400 µg/mL UDCA treated cancer cells was 41.3% versus 10.6% (100 µg/mL) and 22.4% (200 µg/mL). After different concentrations of UDCA treatment, the mRNA and protein expressions of caspase-3, caspase-8, caspase-9, Bax, Fas/FasL (Fas ligand), TRAIL (TNF-related apoptosis-inducing ligand), DR4 (death receptor 4) and DR5 (death receptor 5) were increased in HSC-3 cells, and mRNA and protein expressions of Bcl-2 (B-cell lymphoma 2), Bcl-xL (B-cell lymphoma-extra large), XIAP (X-linked inhibitor of apoptosis protein), cIAP-1 (cellular inhibitor of apoptosis 1), cIAP-2 (cellular inhibitor of apoptosis 2) and survival were decreased. Meanwhile, at the highest concentration of 400 µg/mL, caspase-3, caspase-8, caspase-9, Bax, Fas/FasL, TRAIL, DR4, DR5, and IκB-α expression levels were the highest, and Bcl-2, Bcl-xL, XIAP, cIAP-1, cIAP-2, survival, and NF-κB expression levels were the lowest. These results proved that UDCA could induce apoptosis of HSC-3 cancer cells through caspase activation, and the higher concentration of UDCA had stronger effects in vitro. UDCA might be a good nutrient for oral cancer prevention.