Abstract Background: Hypoxia inducible factor-1 (HIF-1) is considered as the most activated transcriptional factor in response to low oxygen level or hypoxia. HIF-1 binds the hypoxia response element (HRE) sequence in the promoter of different genes, mainly through the bHLH domain and activates the transcription of genes, especially those involved in angiogenesis and EMT. Considering the critical role of bHLH in binding HIF-1 to the HRE sequence, we hypothesized that bHLH could be a promising candidate to be targeted in hypoxia condition. Methods: We inserted an inhibitory bHLH (ibHLH) domain in a pIRES2-EGFP vector and transfected HEK293T cells with either the control vector or the designed construct. The ibHLH domain consisted of bHLH domains of both HIF-1a and Arnt, capable of competing with HIF-1 in binding to HRE sequences. The transfected cells were then treated with 200 μM of cobalt chloride (CoCl2) for 48 h to induce hypoxia. Real-time PCR and western blot were performed to evaluate the effect of ibHLH on the genes and proteins involved in angiogenesis and EMT. Results: Hypoxia was successfully induced in the HEK293T cell line as the gene expression of VEGF, vimentin, and β-catenin were significantly increased after treatment of untransfected HEK293T cells with 200 μM CoCl2. The gene expression of VEGF, vimentin, and β-catenin and protein level of β-catenin were significantly decreased in the cells transfected with either control or ibHLH vectors in hypoxia. However, ibHLH failed to be effective on these genes and the protein level of β-catenin, when compared to the control vector. We also observed that overexpression of ibHLH had more inhibitory effect on gene and protein expression of N-cadherin compared to the control vector. However, it was not statistically significant. Conclusion: bHLH has been reported to be an important domain involved in the DNA binding activity of HIF. However, we found that targeting this domain is not sufficient to inhibit the endogenous HIF-1 transcriptional activity. Further studies about the function of critical domains of HIF-1 are necessary for developing a specific HIF-1 inhibitor.

Abstract Gallic acid (GA), as a strong antioxidant, was selected in this study to investigate its possible nephroprotective effects against gentamicin (GM)-induced nephrotoxicity. Twenty-four rats were separated into three groups (n=8): group 1 (control group) received saline (0.5 mL/day), group 2 (GM group) received GM (100 mg/kg/day), and group 3 (treated group) received GM (100 mg/kg/day) and GA (100mg/kg/day). All treatments were performed intraperitoneally for 12 days. After 12 days, the rats were euthanized, and kidneys were removed immediately. For serum preparation, blood samples were collected before killing. Kidney paraffin sections were prepared from one of the kidneys and stained by the periodic acid-Schiff process. GA significantly decreased GM-induced renal histopathological injuries, including tubular necrosis, tubular cast, and leucocyte infiltration compared with the GM group. Additionally, GA significantly improved proteinuria, serum levels of urea and creatinine, and serum activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) compared with nephrotoxic animals. Furthermore, GA caused a significant improvement in the levels of cholesterol (Chol), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and cardiac risk ratios 1 and 2 in comparison with nephrotoxic animals. GA administration was observed to significantly improve the levels of lipid peroxidation, nitric oxide (NO), and glutathione (GSH) compared with the GM group. Finally, the activities and gene expression levels of catalase (CAT) and glutathione peroxidase (GPX) significantly increased following GA administration compared with the GM group. Our results indicated that GA has potential protective effects against GM nephrotoxicity by reducing oxidative stress in rats.

RESUMO Contexto - O refluxo gastroesofágico é a doença esofágica mais comum em Pediatria. Objetivo - O objetivo deste estudo foi comparar parâmetros de refluxo em pacientes com sintomas típicos e atípicos de refluxo gastroesofágico na população pediátrica usando impedância intraluminal multicanal e monitoramento 24 horas do pH esofágico. Métodos - Neste estudo prospectivo, 43 pacientes com idade inferior a 18 anos com suspeita de refluxo gastroesofágico foram observados. Os pacientes foram divididos em dois grupos com base nos principais sintomas de apresentação (típicos versus atípicos). Foram realizados em todos os pacientes, monitoramento de 24 horas do pH e impedância intraluminal multicanal para comparar esses dois grupos em relação a associação de sintomas e refluxo. Número de refluxos, pH relacionados com refluxo, tempo total de refluxo, refluxo maior do que 5 minutos, tempo mais longo de refluxo, pH mais baixo no refluxo, índice de refluxo foram registrados e comparados. Comparação de dados foi feita usando SPSS. Resultados - A idade média dos pacientes foi 5.7±3.4 anos e 65,1% eram do sexo masculino. Dos 43 pacientes, 24 tinham sintomas típicos e 19 atípicos. A média de eventos de refluxo detectados por impedância intraluminal multicanal foi maior do que a detectada pelo monitoramento do pH (308.4±115.8 vs 69.7±66.6) com P=0,037, que é estatisticamente significativo. O índice médio de sintoma e a probabilidade de associação do sintoma foram 35.01% ± 20.78% e 86.42% ± 25.79%, respectivamente em impedância intraluminal multicanal contra 12,73% ± 12,48% e 45% ± 42,29% em monitoramento do pH (P valor &lt; 0,001). O número de refluxos ácidos foi 46,26±47,16 e 30,9±22,09 para sintomas típicos e atípicos, respectivamente. O índice médio de sintoma foi de 18,12% ± 13,101% e 8,30% ± 10,301% em sintomas típicos e atípicos em respectivamente P=0,034). A limpeza do bolus foi maior no grupo de sintomas atípicos quando comparados a sintomas típicos. (P<0,05) Conclusão -O Índice de sintoma foi significativamente maior nos pacientes com sintomas atípicos em comparação com os de sintomas típicos. Maior número de refluxos ácidos foi encontrado em crianças com sintomas atípicos de refluxo. Maior duração da limpeza do bolus foi encontrada no grupo com sintomas atípicos de refluxo.

ABSTRACT Background - Gastroesophageal reflux disease is the most common esophageal disorder in pediatrics. Objective - The aim of this study was to compare reflux parameters of typical and atypical symptoms of gastroesophageal reflux disease using 24-hour esophageal pH monitoring and multichannel intraluminal impedance in pediatric population. Methods - In this prospective study, 43 patients aged less than 18 year with suspected gastroesophageal reflux disease were enrolled. The patients were divided into two groups based on the main presenting symptoms (typical versus atypical). Twenty four-hour pH monitoring and multichannel intraluminal impedance were performed in all the patients for comparing these two group regarding association of symptoms and reflux. Number of refluxes, pH related reflux, total reflux time, reflux more than 5 minutes, longest time of the reflux, lowest pH at reflux, reflux index were recorded and compared. Data comparison was done using SPSS. Results - The mean age of the patients was 5.7±3.4 years and 65.1% were male. Out of 43 patients 24 cases had typical symptoms and 19 had atypical symptoms. The mean reflux events detected by multichannel intraluminal impedance was more than mean reflux events detected by pH monitoring (308.4±115.8 vs 69.7±66.6) with P value of 0.037, which is statistically significant. The mean symptom index and symptom association probability were 35.01% ± 20.78% and 86.42% ± 25.79%, respectively in multichannel intraluminal impedance versus 12.73% ± 12.48% and 45.16% ± 42.29% in pH monitoring (P value <0.001). Number of acid reflux was 46.26±47.16 and 30.9±22.09 for atypical and typical symptoms respectively. The mean symptom index was 18.12% ± 13.101% and 8.30% ± 10.301% in atypical and typical symptoms respectively (P=0.034). Bolus clearance was longer in atypical symptoms compared typical symptoms(P<0.05). Conclusion - Symptom index was significantly higher in atypical symptoms compared to typical symptoms. Higher number of acid reflux was found in children with atypical symptoms of reflux. Longer duration of bolus clearance was found in group with atypical symptoms of reflux.