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As N-nitrosaminas são compostos orgânicos caracterizados pela ligação de um grupo nitroso a um grupo amina e potencial carcinogênico em exposições por longos períodos. Recentemente, a presença de N-nitrosaminas foi identificada em insumos farmacêuticos ativos (IFAs) e/ou medicamentos como valsartana (anti-hipertensivo), nizatidina, ranitidina (antiulcerosos) e metformina (antidiabético), acarretando no recolhimento de diversos lotes de produtos disponíveis no mercado. Desde então, ações de controle têm sido implementadas pelas agências reguladoras, visando à proteção da saúde do paciente. O objetivo deste trabalho foi elaborar uma revisão narrativa sobre N-nitrosaminas em medicamentos, abordando mecanismos de formação, recomendações regulatórias e aspectos toxicológicos e analíticos de monitoramento. Para isto, foram utilizadas como fontes de consulta bases de dados de órgãos oficiais de saúde, nacionais e internacionais, dentre outras. Verificou-se que a causa mais discutida para a ocorrência de N-nitrosaminas em medicamentos é o emprego de agentes nitrosantes durante a síntese de fármacos. Sendo assim, a principal estratégia de controle é baseada no gerenciamento de risco quanto à formação e toxicidade, para que melhorias nos processos produtivos possibilitem a mitigação destas impurezas. As análises laboratoriais confirmatórias de identificação e quantificação de N-nitrosaminas envolvem técnicas de elevada sensibilidade, destacando-se a cromatografia gasosa ou líquida acoplada à espectroscopia de massas.

Nitrosamines are organic compounds characterized by the chemical bonding of a nitroso group to an amine group, and carcinogenic potential in long-term exposure. Recently, the presence of nitrosamines was identified in active pharmaceutical ingredients (APIs) and/or finished pharmaceutical products (FPPs) such as valsartan (antihypertensive), nizatidine, ranitidine (antiulcer) and metformin (antidiabetic), resulting in the recall of several batches of marketed drugs. Since then, regulatory agencies implemented the control of nitrosamines in drugs, aiming to protect the patient's health. This work conducted a narrative review of nitrosamines in drugs, the mechanisms of formation, regulatory recommendations, and toxicological and analytical aspects of monitoring. For this review, national and international databases of official health agencies were used as reference sources, among others. It was found that the most discussed cause for the occurrence of nitrosamines in drugs is the use of nitrosating agents during the synthesis of APIs. Therefore, the main control strategy is based on risk management regarding formation and toxicity, and the implementation of adjustments in manufacturing processes that enable the mitigation of these impurities. Confirmatory analysis for the identification and quantification of nitrosamines requires highly sensitive techniques, as gas or liquid chromatography coupled with mass spectroscopy.

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The appropriate dosing regimens of secukinumab for psoriatic arthritis (PsA) are not well defined. We performed a meta-analysis to evaluate the efficacy and safety of different dosing regimens of secukinumab in the treatment of PsA. A systematic search was conducted using major electronic databases to identify relevant randomized controlled trials (RCTs) comparing secukinumab 300 mg versus secukinumab 150 mg in patients with PsA. Meta-analysis was performed using Review Manager software (version 5.3). Six studies with a total of 1141 patients were included. At week 24, secukinumab 300 mg was associated with a higher American College of Rheumatology 20% response (ACR 20), ACR 50, PASI 75 response rate, and dactylitis resolution rate than secukinumab 150 mg, especially in the anti-TNF-IR subgroup. At week 52, secukinumab 300 mg was associated with a higher psoriasis area and severity index (PASI) 75 and PASI 90 response rate than secukinumab 150 mg. There was no significant difference between secukinumab 300 mg and secukinumab 150 mg in the risk of any adverse events (AEs) and serious AEs at either week 24 or week 52. Secukinumab 300 mg was significantly more effective than 150 mg, especially for patients with PsA who have failed TNF therapy, and it was well tolerated.

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The appropriate dosing regimens of secukinumab for psoriatic arthritis (PsA) are not well defined. We performed a meta-analysis to evaluate the efficacy and safety of different dosing regimens of secukinumab in the treatment of PsA. A systematic search was conducted using major electronic databases to identify relevant randomized controlled trials (RCTs) comparing secukinumab 300 mg versus secukinumab 150 mg in patients with PsA. Meta-analysis was performed using Review Manager software (version 5.3). Six studies with a total of 1141 patients were included. At week 24, secukinumab 300 mg was associated with a higher American College of Rheumatology 20% response (ACR 20), ACR 50, PASI 75 response rate, and dactylitis resolution rate than secukinumab 150 mg, especially in the anti-TNF-IR subgroup. At week 52, secukinumab 300 mg was associated with a higher psoriasis area and severity index (PASI) 75 and PASI 90 response rate than secukinumab 150 mg. There was no significant difference between secukinumab 300 mg and secukinumab 150 mg in the risk of any adverse events (AEs) and serious AEs at either week 24 or week 52. Secukinumab 300 mg was significantly more effective than 150 mg, especially for patients with PsA who have failed TNF therapy, and it was well tolerated.

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This study aimed to explore: 1) DNA methylation in the promoter regions of Wilms tumor gene 1 (WT1), NK6 transcription factor related locus 1 gene (NKX6-1) and Deleted in bladder cancer 1 (DBC1) gene in cervical cancer tissues of Uygur women in Xinjiang, and 2) the correlation of gene methylation with the infection of HPV16/18 viruses. We detected HPV16/18 infection in 43 normal cervical tissues, 30 cervical intraepithelial neoplasia lesions (CIN) and 48 cervical cancer tissues with polymerase chain reaction (PCR) method. Methylation in the promoter regions of the WT1, NKX6-1 and DBC1 genes in the above-mentioned tissues was measured by methylation-specific PCR (MSP) and cloning sequencing. The expression level of these three genes was measured by real-time PCR (qPCR) in 10 methylation-positive cervical cancer tissues and 10 methylation-negative normal cervical tissues. We found that the infection of HPV16 in normal cervical tissues, CIN and cervical cancer tissues was 14.0, 36.7 and 66.7%, respectively. The infection of HPV18 was 0, 6.7 and 10.4%, respectively. The methylation rates of WT1, NKX6-1 and DBC1 genes were 7.0, 11.6 and 23.3% in normal cervical tissues, 36.7, 46.7 and 30.0% in CIN tissues, and 89.6, 77.1 and 85.4% in cervical cancer tissues. Furthermore, WT1, NKX6-1 and DBC1 genes were hypermethylated in the high-grade squamous intraepithelial lesion (CIN2, CIN3) and in the cervical cancer tissues with infection of HPV16/18 (both P< 0.05). The expression of WT1, NKX6-1 and DBC1 was significantly lower in the methylation-positive cervical cancer tissues than in methylation-negative normal cervical tissues. Our findings indicated that methylation in the promoter regions of WT1, NKX6-1 and DBC1 is correlated with cervical cancer tumorigenesis in Uygur women. The infection of HPV16/18 might be correlated with methylation in these genes. Gene inactivation caused by methylation might be related to the incidence and development of cervical cancer.

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Abstract This study aimed to explore: 1) DNA methylation in the promoter regions of Wilms tumor gene 1 (WT1), NK6 transcription factor related locus 1 gene (NKX6-1) and Deleted in bladder cancer 1 (DBC1) gene in cervical cancer tissues of Uygur women in Xinjiang, and 2) the correlation of gene methylation with the infection of HPV16/18 viruses. We detected HPV16/18 infection in 43 normal cervical tissues, 30 cervical intraepithelial neoplasia lesions (CIN) and 48 cervical cancer tissues with polymerase chain reaction (PCR) method. Methylation in the promoter regions of the WT1, NKX6-1 and DBC1 genes in the above-mentioned tissues was measured by methylation-specific PCR (MSP) and cloning sequencing. The expression level of these three genes was measured by real-time PCR (qPCR) in 10 methylation-positive cervical cancer tissues and 10 methylation-negative normal cervical tissues. We found that the infection of HPV16 in normal cervical tissues, CIN and cervical cancer tissues was 14.0, 36.7 and 66.7%, respectively. The infection of HPV18 was 0, 6.7 and 10.4%, respectively. The methylation rates of WT1, NKX6-1 and DBC1 genes were 7.0, 11.6 and 23.3% in normal cervical tissues, 36.7, 46.7 and 30.0% in CIN tissues, and 89.6, 77.1 and 85.4% in cervical cancer tissues. Furthermore, WT1, NKX6-1 and DBC1 genes were hypermethylated in the high-grade squamous intraepithelial lesion (CIN2, CIN3) and in the cervical cancer tissues with infection of HPV16/18 (both P< 0.05). The expression of WT1, NKX6-1 and DBC1 was significantly lower in the methylation-positive cervical cancer tissues than in methylation-negative normal cervical tissues. Our findings indicated that methylation in the promoter regions of WT1, NKX6-1 and DBC1 is correlated with cervical cancer tumorigenesis in Uygur women. The infection of HPV16/18 might be correlated with methylation in these genes. Gene inactivation caused by methylation might be related to the incidence and development of cervical cancer.

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Background: Chrysanthemum plants are subject to serious viral diseases. The viruses cause severe losses of the quantity and quality of chrysanthemum. The most problematic pathogen of chrysanthemum is typically considered Chrysanthemum virus B (CVB). Thus, a method for the simultaneous detection of CVB is needed. Results: We used gene-specific primers, which were derived from the coat protein gene region of the virus, for reverse transcription to obtain cDNA. Nested amplification polymerase chain reaction (PCR) was employed to detect the viral gene. This method was sensitive enough to detect the virus at up to 10-9 dilution of the cDNA. Conclusion: A highly specific and sensitive nested PCR-based assay has been described for detecting CVB. This new method is highly specific and sensitive for the detection of CVB, which is known to infect chrysanthemum plants in the fields. Further, this protocol has an advantage over traditional methods as it is more cost-effective. This assay is ideal for an early stage diagnosis of the disease.

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Background: 3-Ketosteroid-∆¹-dehydrogenase (KSDD), a flavoprotein enzyme, catalyzes the bioconversion of 4-androstene-3,17-dione (AD) to androst-1,4-diene-3,17-dione (ADD). To date, there has been no report about characterization of KSDD from Mycobacterium neoaurum strains, which were usually employed to produce AD or ADD by fermentation. Results: In this work, Corynebacterium crenatum was chosen asa new host for heterologous expression of KSDD from M. neoaurum JC-12 after codon optimization of the KSDD gene. SDS-PAGE and western blotting results indicated that the recombinant C. crenatum harboring the optimized ksdd (ksdd n) gene showed significantly improved ability to express KSDD. The expression level of KSDD was about 1.6-fold increased C. crenatum after codon optimization. After purification of the protein, we first characterized KSDD from M. neoaurum JC-12, and the results showed that the optimum temperature and pH for KSDD activity were 30°C and pH 7.0, respectively. The Km and Vmax values of purified KSDD were 8.91 µM and 6.43 mM/min. In this work, C. crenatum as a novel whole-cell catalyst was also employed and validated for bioconversion of AD to ADD. The highest transformation rate of AD to ADD by recombinant C. crenatum was about 83.87% after 10 h reaction time, which was more efficient than M. neoaurum JC-12 (only 3.56% at 10 h). Conclusions: In this work, basing on the codon optimization, overexpression, purification and characterization of KSDD, we constructed a novel system, the recombinant C. crenatum SYPA 5-5 expressing KSDD, to accumulate ADDfromADefficiently. This work provided new insights into strengthening sterol catabolism by overexpressing the key enzyme KSDD, for efficient ADD production.

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The influence of silicate on the transport and deposition of bacteria (Escherichia coli) in packed porous media were examined at a constant 20 mM ionic strength with different silicate concentrations (from 0 to 1 mM) at pH 7. Transport experiments were performed in two types of representative porous media, both bare quartz sand and iron mineral-coated quartz sand. In bare quartz sand, the breakthrough plateaus in the presence of silicate in suspensions were lower and the corresponding retained profiles were higher than those without silicate ions, indicating that the presence of silicate in suspensions decreased cell transport in bare quartz sand. Moreover, the decrease of bacteria transport in quartz sand induced by silicate was more pronounced with increasing silicate concentrations from 0 to 1 mM. However, when EPS was removed from cell surfaces, the presence of silicate in cell suspensions (with different concentrations) did not affect the transport behavior of bacteria in quartz sand. The interaction of silicate with EPS on cell surfaces negatively decreased the zeta potentials of bacteria, resulting in the decreased cell transport in bare quartz sand when silicate was copresent in bacteria suspensions. In contrast, the presence of silicate in suspensions increased cell transport in iron mineral-coated sand. Silicate ions competed with bacteria for the adsorption sites on mineral-coated sand, contributing to the increased cell transport in mineral-coated sand with silicate present in cell suspensions.

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