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2.
Biol Trace Elem Res ; 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38656680

RESUMO

Tobacco smoking is becoming one of the major worldwide concerns regarding environmental pollution as well as health threats. In 2005, the World Health Organization (WHO) released the Framework Convention On Tobacco Control (FCTC), which outlined protocols for controlling tobacco products. Oman was one of the leading countries to follow these protocols; however, Egypt has only followed these protocols recently in 2020. One of the main challenges in tobacco product control is the variation in their trace element's types and amounts from country to country owing to differences in agriculture techniques and used chemical additives. Smoking releases different toxic metal ions found in them into the air, and hence, analyzing trace amounts of metals in tobacco smoking products is becoming more critical. The proposed research aims to evaluate the current levels of 11 heavy metals (namely, As, Pb, Cd, Co, Cr, Be, Ba, Mn, Ni, Fe, and Hg) in 22 tobacco products available in Egypt and Oman using inductively coupled plasma optical emission spectroscopy and a direct mercury analyzer. Although some elements such as Be, Co, and Cd were absent, the positive detection of As and Pb and the levels of Ba, Cr, and Ni are still alarming, especially for heavy smokers. The obtained results were then statistically related to previously published data in 2017 to explore the effectiveness of implementing the FCTC protocols within the Egyptian market. The outcomes suggested a positive impact of FCTC protocol implementation in Egypt, besides the lower levels of elemental content for Omani products compared to the Egyptian market.

3.
RSC Adv ; 14(15): 10445-10451, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38567336

RESUMO

Avapritinib (AVA) is the first medication authorized by the US-FDA in 2020 for the management of gastrointestinal stromal tumours (GISTs) that can't be treated by surgery. Cancer is among the most common causes of death worldwide and is the second most common cause of death after cardiovascular disease. Therefore, a quick, easy, sensitive, and straightforward fluorimetric approach was used to analyse AVA in pharmaceutical materials and blood plasma (pharmacokinetic). The suggested technique relies on 2% sodium dodecyl sulphate (SDS, pH 4) micellar system augmentation of the fluorescence of the tested drug. The technique demonstrated high relative fluorescence intensity (RFI) at 430 nm after excitation at 340 nm. Concentrations ranging from 20.0-400.0 ng mL-1 with a limit of quantitation of 9.47 ng mL-1 were used to obtain luminescence data for the studied medicine. In addition, the quantum yield of the AVA fluorescence was increased with the gradual addition of a surfactant at a concentration above its critical micellar level. This knowledge has been exploited to enhance the effectiveness of a spectrofluorometric technique for the estimation of AVA in human plasma (98.95 ± 1.22%) and uniformity tests with greenness assessments. The conditions for enhanced fluorescence were optimized and fully validated using US-FDA and International Conference on Harmonization (ICH) rules. This innovative strategy was expanded for AVA stability research in human plasma across various circumstances. This approach is an eco-friendly solution compared to traditional testing methods that use hazardous chemicals.

4.
Cell Rep ; 42(8): 112960, 2023 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-37556322

RESUMO

The small ubiquitin-like modifier (SUMO) protease SENP6 disassembles SUMO chains from cellular substrate proteins. We use a proteomic method to identify putative SENP6 substrates based on increased apparent molecular weight after SENP6 depletion. Proteins of the lamin family of intermediate filaments show substantially increased SUMO modification after SENP6 depletion. This is accompanied by nuclear structural changes remarkably like those associated with laminopathies. Two SUMO attachment sites on lamin A/C are close to sites of mutations in Emery-Driefuss and limb girdle muscular dystrophy. To establish a direct link between lamin SUMOylation and the observed phenotype, we developed proximity-induced SUMO modification (PISM), which fuses a lamin A/C targeting DARPin to a SUMO E3 ligase domain. This directly targets lamin A/C for SUMO conjugation and demonstrates that enhanced lamin SUMO modification recapitulates the altered nuclear structure manifest after SENP6 depletion. This shows SENP6 activity protects the nucleus against hyperSUMOylation-induced laminopathy-like alterations.


Assuntos
Lamina Tipo A , Peptídeo Hidrolases , Lamina Tipo A/metabolismo , Peptídeo Hidrolases/metabolismo , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Ubiquitina/metabolismo , Cisteína Endopeptidases/metabolismo , Proteômica , Sumoilação
5.
Anal Bioanal Chem ; 415(22): 5529-5538, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37432444

RESUMO

Copper (Cu) plays a role in maintaining healthy nerve cells and the immune system. Osteoporosis is a high-risk factor for Cu deficiency. In the proposed research, unique green, fluorescent cysteine-doped MnO2 quantum dots (Cys@MnO2 QDs) were synthesized and assessed for the determination of Cu in different food and hair samples. The developed quantum dots were synthesized with the help of cysteine using a straightforward ultrasonic approach to create 3D fluorescent Cys@MnO2 QDs. The resulting QDs' morphological and optical characteristics were carefully characterized. By adding Cu ions, the intensity of fluorescence for the produced Cys@MnO2 QDs was found to be dramatically reduced. Additionally, the applicability of Cys@MnO2 QDs as a new luminous nanoprobe was found to be strengthened by the quenching effect grounded on the Cu-S bonding. The concentrations of Cu2+ ions were estimated within the range of 0.06 to 7.00 µg mL-1, with limit of quantitation equal to 33.33 ng mL-1 and detection limit equal to 10.97 ng mL-1. The Cys@MnO2 QD technique was applied successfully for the quantification of Cu in a variety of foods, including chicken meat, turkey, and tinned fish, as well as in human hair samples. The chance that this novel technique could be a useful tool for figuring out the amount of cysteine in bio-samples is increased by the sensing system's remarkable advantages, which include being rapid, simple, and economical.


Assuntos
Pontos Quânticos , Cobre/química , Pontos Quânticos/química , Cisteína/química , Espectrometria de Fluorescência/métodos , Fatores de Tempo
6.
Medicina (Kaunas) ; 59(7)2023 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-37512045

RESUMO

Background: LGR5 is one of the most important stem cell markers for colorectal cancer (CRC), as it potentiates Wnt/Β-catenin signaling. The well-characterized deregulation of Wnt/Β-catenin signaling that occurs during adenoma/carcinoma sequence in CRC renders LGR5 a hopeful therapeutic target. We assessed the immunohistochemical expression of LGR5 and Β-catenin in normal colonic and tumorous lesions with a clinicopathological correlation. Methods: Tissue blocks and clinical data of 50 selected cases were included: 8 from normal mucosa, 12 cases of adenoma, and 30 cases of CRC, where sections were cut and re-examined and the immunohistochemical technique was conducted using anti-LGR5 and anti-Β-catenin to measure the staining density. Results: There was no expression of LGR5 in normal mucosa compared to samples of adenoma and CRC samples. The association analysis showed that CRC specimens were more likely to have strong LGR5 and Β-catenin expressions than the other two groups (p = 0.048 and p < 0.001, respectively). Specimens with high-grade dysplastic adenoma were more likely to express moderate-to-strong expression of LGR5 and Β-catenin (p = 0.013 and p = 0.036, respectively). In contrast, there were no statistically significant associations between LGR5 and Β-catenin expression with grade and stage. Conclusion: These results suggest and support the possible role of LGR5 as a potential marker of cancer stem cells in sporadic colorectal carcinogenesis in addition to a prognostic value for LGR5 and Β-catenin in adenomatous lesions according to immunohistochemical expression density. A potential therapeutic role of LGR5 in CRC is suggested for future studies based on its role in pathogenesis.


Assuntos
Adenoma , Neoplasias Colorretais , Humanos , Adenoma/patologia , Cateninas/metabolismo , Neoplasias Colorretais/tratamento farmacológico , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia
7.
Medicina (Kaunas) ; 58(12)2022 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-36556921

RESUMO

Background and Objectives: Fibrotic lung disease is one of the main complications of many medical conditions. Therefore, the use of anti-fibrotic agents may provide a chance to prevent, or at least modify, such complication. The aim of this study was to evaluate the protective pulmonary anti-fibrotic and anti-inflammatory effects of Dinebra retroflexa. Materials and methods: Dinebra retroflexa methanolic extract and its synthesized silver nanoparticles were tested on bleomycin-induced pulmonary fibrosis. Pulmonary fibrosis was induced by intratracheal instillation of bleomycin (5 mg/5 mL/kg-Saline) as a supposed model for induced lung fibrosis. The weed evaluation was performed by intratracheal instillation of Dinebra retroflexa methanolic extract and its silver nanoparticles (35 mg/100 mL/kg-DMSO, single dose). Results: The results showed that both Dinebra retroflexa methanolic extract and its silver nanoparticles had a significant pulmonary fibrosis retraction potential, with Ashcroft scores of three and one, respectively, and degrees of collagen deposition reduction of 33.8 and 46.1%, respectively. High-resolution UHPLC/Q-TOF-MS/MS metabolic profiling and colorimetrically polyphenolic quantification were performed for further confirmation and explanation of the represented effects. Such activity was believed to be due to the tentative identification of twenty-seven flavonoids and one phenolic acid along with a phenolic content of 57.8 mg/gm (gallic acid equivalent) and flavonoid content of 22.5 mg/gm (quercetin equivalent). Conclusion: Dinebra retroflexa may be considered as a promising anti-fibrotic agent for people at high risk of complicated lung fibrosis. The results proved that further clinical trials would be recommended to confirm the proposed findings.


Assuntos
Nanopartículas Metálicas , Fibrose Pulmonar , Humanos , Ratos , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/tratamento farmacológico , Bleomicina/efeitos adversos , Nanopartículas Metálicas/uso terapêutico , Prata/farmacologia , Suíça , Espectrometria de Massas em Tandem , Fitoterapia , Pulmão/patologia
8.
Molecules ; 27(24)2022 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-36557948

RESUMO

In our continuous study for some African plants as a source for antitrypanosomally and cytotoxic active drugs, nine different plants belonging to the Crassulaceae family have been selected for the present study. Sedum sieboldii leaves extract showed an antitrypanosomal activity against Trypanosoma brucei with an IC50 value of 8.5 µg/mL. In addition, they have cytotoxic activities against (HCT-116), (HEPG-2) and (MCF-7), with IC50 values of 28.18 ± 0.24, 22.05 ± 0.66, and 26.47 ± 0.85 µg/mL, respectively. Furthermore, the extract displayed inhibition against Topoisomerase-1 with an IC50 value of 1.31 µg/mL. It showed the highest phenolics and flavonoids content among the other plants' extracts. In order to identify the secondary metabolites which may be responsible for such activities, profiling of the polar secondary metabolites of S. sieboldii extract via Ultra-Performance Liquid Chromatography coupled to High-Resolution QTOF-MS operated in negative and positive ionization modes, which revealed the presence of 46 metabolites, including flavonoids, phenolic acids, anthocyanidins, coumarin, and other metabolites.


Assuntos
Antineoplásicos , Espectrometria de Massas em Tandem , Humanos , Cromatografia Líquida de Alta Pressão/métodos , Extratos Vegetais/química , Antineoplásicos/farmacologia , Flavonoides/química , População Africana
9.
J Biol Chem ; 298(12): 102690, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36372232

RESUMO

RNA Polymerase I (Pol I) synthesizes rRNA, which is the first and rate-limiting step in ribosome biogenesis. Factors governing the stability of the polymerase complex are not known. Previous studies characterizing Pol I inhibitor BMH-21 revealed a transcriptional stress-dependent pathway for degradation of the largest subunit of Pol I, RPA194. To identify the E3 ligase(s) involved, we conducted a cell-based RNAi screen for ubiquitin pathway genes. We establish Skp-Cullin-F-box protein complex F-box protein FBXL14 as an E3 ligase for RPA194. We show that FBXL14 binds to RPA194 and mediates RPA194 ubiquitination and degradation in cancer cells treated with BMH-21. Mutation analysis in yeast identified lysines 1150, 1153, and 1156 on Rpa190 relevant for the protein degradation. These results reveal the regulated turnover of Pol I, showing that the stability of the catalytic subunit is controlled by the F-box protein FBXL14 in response to transcription stress.


Assuntos
Proteínas F-Box , Proteínas Ligases SKP Culina F-Box , Transcrição Gênica , Domínio Catalítico , Proteínas F-Box/genética , Proteínas F-Box/metabolismo , RNA Polimerase I/genética , RNA Polimerase I/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas Ligases SKP Culina F-Box/genética , Proteínas Ligases SKP Culina F-Box/metabolismo , Ubiquitinação , Humanos , Transcrição Gênica/genética
10.
Molecules ; 27(12)2022 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-35744781

RESUMO

In 2018, the discovery of carcinogenic nitrosamine process related impurities (PRIs) in a group of widely used drugs led to the recall and complete withdrawal of several medications that were consumed for a long time, unaware of the presence of these genotoxic PRIs. Since then, PRIs that arise during the manufacturing process of the active pharmaceutical ingredients (APIs), together with their degradation impurities, have gained the attention of analytical chemistry researchers. In 2020, favipiravir (FVR) was found to have an effective antiviral activity against the SARS-COVID-19 virus. Therefore, it was included in the COVID-19 treatment protocols and was consequently globally manufactured at large-scales during the pandemic. There is information indigence about FVR impurity profiling, and until now, no method has been reported for the simultaneous determination of FVR together with its PRIs. In this study, five advanced multi-level design models were developed and validated for the simultaneous determination of FVR and two PRIs, namely; (6-chloro-3-hydroxypyrazine-2-carboxamide) and (3,6-dichloro-pyrazine-2-carbonitrile). The five developed models were classical least square (CLS), principal component regression (PCR), partial least squares (PLS), genetic algorithm-partial least squares (GA-PLS), and artificial neural networks (ANN). Five concentration levels of each compound, chosen according to the linearity range of the target analytes, were used to construct a five-level, three-factor chemometric design, giving rise to twenty-five mixtures. The models resolved the strong spectral overlap in the UV-spectra of the FVR and its PRIs. The PCR and PLS models exhibited the best performances, while PLS proved the highest sensitivity relative to the other models.


Assuntos
Tratamento Farmacológico da COVID-19 , Algoritmos , Amidas , Antivirais/farmacologia , Antivirais/uso terapêutico , Calibragem , Humanos , Análise dos Mínimos Quadrados , Pirazinas/uso terapêutico
11.
R Soc Open Sci ; 9(6): 220250, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35706671

RESUMO

Angiotensin-converting enzyme inhibitors are one of the most widely used anti-hypertensive drugs which are used to reduce hypertension. In 2018, the United States Food and Drug Administration together with the European Medicine Agency declared the presence of carcinogenic nitrosamine impurities such as nitrosodiethylamine (NDEA) in some of the products, including valsartan (VLS) and losartan (LOS), and drugs' recall procedures were started. Thus, they should be controlled to be below the acceptable cancer risk level to ensure safety of the pharmaceutical products. Therefore, sensitive and reliable analytical methods were required for detection and quantitation of NDEA in bulk and finished drug products. Green analytical chemistry has received great interest to minimize the amount of organic solvents consumed without loss in chromatographic performance. A green and sensitive HPLC method was developed for the determination of NDEA in LOS and VLS using mobile phase of 0.02 M ammonium acetate adjusted to pH 7.2 and ethanol in gradient manner. Limits of detection and limits of quantification for NDEA were estimated to be 0.2 and 0.5 µg ml-1, respectively. The standardized limits of NDEA impurity in drug substances were set as 0.56 ppm, which indicates the feasibility of its determination by the proposed conventional method without need for expensive instrumentations (e.g. MS/MS detectors) that are not found in most pharmaceutical quality control laboratories.

12.
Anal Methods ; 13(23): 2596-2602, 2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-34019051

RESUMO

Fluorescence spectroscopy has gained much attention over the last few years. Its advantages cover both analytical performance as well as ecological greenness. The quality control of pharmaceuticals requires sensitive, fast and economic methodologies to provide a high throughput at desirable costs. The low energy and decreased solvent consumption make this technique green as well as economic, and hence it is much preferred by pharmaceutical industries. Remdesivir is a recent antiviral, previously used for the treatment of Ebola virus infections, which was approved by the US-FDA in 2020 for treatment of infections caused by SARS-CoV-2 virus. Formulation and wide-scale production of this drug started recently and hence methodologies related to its quality control are highly required. A smart spectrofluorimetric method was validated as per the US-FDA guidelines for the facile estimation of Remdesivir. The assay of Remdesivir was based on its native fluorescence measurements at pH 4 and wavelengths of 244/405 nm. Calibration was achieved over the range of 1.0-65.0 ng mL-1. Different variables affecting the proposed methodology were studied to achieve maximum sensitivity, at limits of detection and quantification of 0.287 and 0.871 ng mL-1, respectively. The developed method is regarded as the first spectrofluorimetric one for the estimation of Remdesivir. The developed method was also utilized for the determination of the drug in its formulated IV infusion and in spiked human plasma. Statistical analysis verified that this method is accurate and reproducible. Moreover, the ecological impact of the developed procedures was evaluated on two recently reported assessment metrics, the Green Analytical Procedure Index (GAPI) and AGREE-analytical greenness metric, to emphasize the greenness of the procedure.


Assuntos
Tratamento Farmacológico da COVID-19 , Preparações Farmacêuticas , Monofosfato de Adenosina/análogos & derivados , Alanina/análogos & derivados , Antivirais , Humanos , SARS-CoV-2 , Espectrometria de Fluorescência
13.
Ann Med Surg (Lond) ; 60: 425-430, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33251000

RESUMO

BACKGROUND: Routine histopathological examination (RHPE) of all gallbladder specimens is required to detect the presence of gallbladder carcinoma (GBC) or any other pathology. The work aims to study the incidence and the clinical significance of detecting unusual gallbladder findings upon the RHPE of the referred cholecystectomy specimens to a histopathology laboratory section at a referral hospital in Saudi Arabia during one year period. MATERIALS AND METHODS: From May 2019 to May 2020, all histopathology reports of 444 consecutive gallbladder specimens after elective and emergency cholecystectomies were retrospectively analyzed and divided into two groups; usual findings and unusual findings which were reviewed blindly by two other pathology consultants. Frequencies, descriptive statistics, normality test, and correlations were run. The Interrater reliability between clinical and histopathological diagnosis was assessed statistically by kappa test. RESULTS: The results of histopathological examination of these gallbladder specimens showed that chronic cholecystitis was found in 296 out of 444 total cases (66.7%), acute cholecystitis in 52 cases (11.7%), and other associated usual findings in 85 cases (19%). Three cases (0.7%) of incidental carcinomas and other three cases (0.7%) of dysplasia. Eosinophilic carcinomas were detected in two cases (0.45%), gallbladder complete septum was found in one case, and one case of Phrygian cap anomaly. All patients with gallbladder carcinoma were diagnosed incidentally during the histopathological examination. CONCLUSIONS: RHPE of cholecystectomy materials are required to confirm the final diagnosis and document any other pathology. Failure to detect incidental occult carcinoma may be catastrophic, given the poor prognosis.

14.
J Sep Sci ; 43(16): 3224-3232, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32510825

RESUMO

Minimizing the amount of organic solvents without loss in chromatographic performance has been an important step toward greening analytical methodologies. Mobile-phase composition is the key for maintaining separation efficiency in liquid chromatography while decreasing the procedure hazardousness. If sodium dodecyl sulfate is mixed with Brij-35 in the mobile phase, they could be used as a green alternative for using organic modifiers. In this research, the effect of changing the relative amounts of both surfactants was studied on the chromatographic performance and separation efficiency of ten antihypertensive drugs belonging to different categories. The use of surfactants has many advantages including low cost and toxicity, safe environmental disposal, unique selectivity besides high solubilization capabilities. The optimum separation was maintained using a mobile phase (0.01 M Brij-35, 0.08 M sodium dodecyl sulfate and 0.01 M sodium dihydrogen phosphate/pH 5) on reversed-phase C18 core-shell column at flow rate 1.5 mL/min and temperature 30°C. The method was successfully applied for the determination of the drugs in various marketed dosage forms. International Conference of Harmonization guidelines were followed to validate the developed method. Additionally, the method was verified on the Green Analytical Procedure Index in regards to the greenness and found to be an excellent green alternative method.


Assuntos
Anti-Hipertensivos/análise , Química Verde , Cromatografia Líquida de Alta Pressão , Cromatografia de Fase Reversa , Micelas , Estrutura Molecular
15.
J Invest Dermatol ; 140(6): 1154-1165.e5, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31705877

RESUMO

We performed a small interfering RNA screen to identify targets for cutaneous squamous cell carcinoma (cSCC) therapy in the ubiquitin/ubiquitin-like system. We provide evidence for selective anti-cSCC activity of knockdown of the E3 ubiquitin ligase MARCH4, the ATPase p97/VCP, the deubiquitinating enzyme USP8, the cullin-RING ligase (CRL) 4 substrate receptor CDT2/DTL, and components of the anaphase-promoting complex/cyclosome (APC/C). Specifically attenuating CRL4CDT2 by CDT2 knockdown can be more potent in killing cSCC cells than targeting CRLs or CRL4s in general by RBX1 or DDB1 depletion. Suppression of the APC/C or forced APC/C activation by targeting its repressor EMI1 are both potential therapeutic approaches. We observed that cSCC cells can be selectively killed by small-molecule inhibitors of USP8 (DUBs-IN-3/compound 22c) and the NEDD8 E1 activating enzyme/CRLs (MLN4924/pevonedistat). A substantial proportion of cSCC cell lines are very highly MLN4924-sensitive. Pathways that respond to defects in proteostasis are involved in the anti-cSCC activity of p97 suppression. Targeting USP8 can reduce the expression of growth factor receptors that participate in cSCC development. EMI1 and CDT2 depletion can selectively cause DNA re-replication and DNA damage in cSCC cells.


Assuntos
Carcinoma de Células Escamosas/tratamento farmacológico , Neoplasias Cutâneas/tratamento farmacológico , Carcinoma de Células Escamosas/patologia , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Ciclopentanos/farmacologia , Ciclopentanos/uso terapêutico , Ensaios de Seleção de Medicamentos Antitumorais , Endopeptidases/genética , Endopeptidases/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/antagonistas & inibidores , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Proteínas F-Box/antagonistas & inibidores , Proteínas F-Box/genética , Proteínas F-Box/metabolismo , Técnicas de Silenciamento de Genes , Humanos , Terapia de Alvo Molecular/métodos , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , RNA Interferente Pequeno/metabolismo , Neoplasias Cutâneas/patologia , Ubiquitina Tiolesterase/antagonistas & inibidores , Ubiquitina Tiolesterase/genética , Ubiquitina Tiolesterase/metabolismo , Enzimas Ativadoras de Ubiquitina/antagonistas & inibidores , Enzimas Ativadoras de Ubiquitina/genética , Enzimas Ativadoras de Ubiquitina/metabolismo
16.
Mol Cell ; 75(3): 483-497.e9, 2019 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-31253574

RESUMO

In mammals, ∼100 deubiquitinases act on ∼20,000 intracellular ubiquitination sites. Deubiquitinases are commonly regarded as constitutively active, with limited regulatory and targeting capacity. The BRCA1-A and BRISC complexes serve in DNA double-strand break repair and immune signaling and contain the lysine-63 linkage-specific BRCC36 subunit that is functionalized by scaffold subunits ABRAXAS and ABRO1, respectively. The molecular basis underlying BRCA1-A and BRISC function is currently unknown. Here we show that in the BRCA1-A complex structure, ABRAXAS integrates the DNA repair protein RAP80 and provides a high-affinity binding site that sequesters the tumor suppressor BRCA1 away from the break site. In the BRISC structure, ABRO1 binds SHMT2α, a metabolic enzyme enabling cancer growth in hypoxic environments, which we find prevents BRCC36 from binding and cleaving ubiquitin chains. Our work explains modularity in the BRCC36 DUB family, with different adaptor subunits conferring diversified targeting and regulatory functions.


Assuntos
Proteína BRCA1/genética , Reparo do DNA/genética , Proteínas de Ligação a DNA/genética , Enzimas Desubiquitinantes/genética , Chaperonas de Histonas/genética , Neoplasias/genética , Sítios de Ligação/genética , Proteínas de Transporte/genética , Núcleo Celular/genética , Núcleo Celular/imunologia , Citoplasma/genética , Citoplasma/imunologia , Quebras de DNA de Cadeia Dupla , Reparo do DNA/imunologia , Enzimas Desubiquitinantes/imunologia , Células HeLa , Humanos , Imunidade Celular/genética , Complexos Multiproteicos/química , Complexos Multiproteicos/genética , Neoplasias/imunologia , Proteínas Associadas à Matriz Nuclear/genética , Ligação Proteica/genética , Ubiquitina/genética , Proteases Específicas de Ubiquitina/genética , Ubiquitinação/genética
17.
Int J Biol Macromol ; 129: 31-40, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30716378

RESUMO

A novel glucose isomerase gene from the thermophilic Caldicoprobacter algeriensis, encoding a polypeptide of 438 residues, was identified, cloned and successfully expressed in E. coli. The purified enzyme (GICA) was a homotetramer of about 200 kDa displaying the highest activity at pH 7.0 and 90 °C and retaining 97% of its maximum activity at pH 6.5. The enzyme showed an excellent thermostability with a half-life of 6 min at 100 °C. Interestingly, GICA had a very high affinity of 40 mM and catalytic efficiency of 194 min-1 mM-1 toward d-glucose at 90 °C. A maximum of 54.7% d-glucose to d-fructose conversion was achieved by GICA at 85 °C making it an attractive candidate for HFCS-55 production. The primary sequence inspection and molecular modeling studies revealed that the thermal stability of GICA could be attributed to the presence of extra charged residues at the surface like E108 and Q408 increasing surface charge interactions. Moreover, a serine at position 56 near to P58 could establish hydrogen bond strengthening the dimer attachment. The high catalytic efficiency and affinity of GICA could be ascribed to the presence of amino acid like E108 and K62 that created more charges around the catalytic site entry.


Assuntos
Aldose-Cetose Isomerases/química , Aldose-Cetose Isomerases/metabolismo , Bactérias/enzimologia , Termodinâmica , Aldose-Cetose Isomerases/genética , Sequência de Aminoácidos , Bactérias/classificação , Bactérias/genética , Fenômenos Químicos , Clonagem Molecular , Ativação Enzimática , Estabilidade Enzimática , Frutose/metabolismo , Expressão Gênica , Xarope de Milho Rico em Frutose/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Modelos Moleculares , Conformação Molecular , Filogenia , Proteínas Recombinantes , Relação Estrutura-Atividade , Temperatura
18.
J Family Community Med ; 25(1): 13-19, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29386957

RESUMO

BACKGROUND: Despite clear evidence indicating the health hazards of water tobacco smoking (WTS), there is a remarkable increase in the frequency of WTS in the Middle East and the Gulf region, particularly among young girls and women. The objective of this survey was to examine the prevalence of and the reasons for addiction to WTS and study in depth the factors contributing to the increased frequency of WTS among Saudi females. MATERIALS AND METHODS: This study was conducted in different cafés and restaurants in Jeddah using a mixed method approach. A quantitative approach was carried out by a cross-sectional design, in which adult WTS Saudi females (n = 332) were selected from ten cafés. In addition, a qualitative approach was pursued involving five focus group discussions and three in-depth interviews of heavy smokers. Frequencies and percentages were calculated for the categorical variables, and Chi-square test and regression analysis were performed to establish association. Key themes were identified and built upon for the qualitative part. RESULTS: The mean age of female water-pipe (WP) smokers was 32.5 ± 11.9 years. Addicted to WTS were 39.6% of the women. Significant predictors of smokers' addiction to WTS according to regression analysis (p < 0.05) were increased frequency of WTS, perception that it improved mood, and insistence on carrying one's own WP to restaurants and cafés. Smoking frequency increased in pleasant weather (p = 0.025) and better mood (p = 0.033). This study showed that students and working women were more addicted to WTS (p < 0.001). Those who smoked daily preferred to smoke at home especially when alone (p < 0.001), while the preferred place for those who smoked weekly was restaurants in the company of their friends (p < 0.001). Most of the participants in this study believed that WTS was less harmful and less addictive than cigarette smoking. The only driving force to quit WTS was the effects on their beauty/skin. CONCLUSION: WTS is a public health problem, especially among young girls. Peer pressure, view that it is a fashion symbol, carrying one's own WP and wrong belief that WP was less harmful, improved mood, and effect of the weather are main factors leading to unintentional dependency on WTS. The only driving force to stop WTS is the effect it has on beauty/skin. It is important to understand the reasons behind the upsurge of WTS in this group for appropriate policy for intervention for its prevention and cessation.

19.
Neuro Endocrinol Lett ; 37(1): 46-52, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26994385

RESUMO

OBJECTIVES: Glutathione S-transferase pi (GSTP1) is a candidate enzyme that may be involved in colorectal cancer susceptibility. Polymorphism of GSTP1 gene may cause changes in expression or structure which lead to alteration in the efficiency of catalytic function of the enzyme variants, i.e., deficient detoxification of carcinogens and consequently influences coloreActal cancer development. The present report examined the possible impact of GSTP1 (Ilel05Val) polymorphism and the risk of colorectal cancer. METHODS: Samples of paraffin embedded tissues from 83 patients with colorectal cancer as well as thirty five non-cancerous colon tissues were collected from the archive of the pathology department at King Abdulaziz University in Saudi Arabia. All cancer and control samples were subjects to DNA extraction then amplification. DNA genetic analyzer from Applied Biosystems was used to sequence the product of amplification for genotypes determination. RESULTS: None of the genotypes of GSTP1 was associated with the risk of colorectal cancer development. There were no statistical differences in the frequencies of GSTP1 genotypes between colorectal cancer cases and controls. CONCLUSION: The incidence of (Val/Val) genotype in colorectal cancer cases was three folds higher than controls. This finding is not statistically significant, but it could be of clinical consequence that it may increase the risk of colorectal cancer in Saudi Arabia.


Assuntos
Neoplasias Colorretais/genética , Predisposição Genética para Doença , Glutationa S-Transferase pi/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Substituição de Aminoácidos/genética , Estudos de Casos e Controles , Neoplasias Colorretais/epidemiologia , Feminino , Frequência do Gene , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Arábia Saudita/epidemiologia , Valina/genética
20.
Emerg Infect Dis ; 21(8): 1422-5, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26196891

RESUMO

We determined the presence of neutralizing antibodies to Middle East respiratory syndrome coronavirus in persons in Qatar with and without dromedary contact. Antibodies were only detected in those with contact, suggesting dromedary exposure as a risk factor for infection. Findings also showed evidence for substantial underestimation of the infection in populations at risk in Qatar.


Assuntos
Camelus/virologia , Infecções por Coronavirus/epidemiologia , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Exposição Ocupacional/estatística & dados numéricos , Zoonoses/epidemiologia , Animais , Anticorpos Antivirais/sangue , Camelus/imunologia , Humanos , Exposição Ocupacional/efeitos adversos , Catar/epidemiologia , Risco
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