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1.
BMC Complement Altern Med ; 18(1): 240, 2018 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-30134897

RESUMEN

BACKGROUND: Here, we determined in vitro antioxidant activity, total phenols and flavonoids and evaluated antiproliferative activity of three medicinal plant extracts: Trigonella foenum-graecum (Fenugreek), Cassia acutifolia (Senna) and Rhazya stricta (Harmal). METHODS: The leaves of the three medicinal plants were extracted with 70% ethanol. Antioxidant activities of the extracts were determined by using DPPH (1,1-diphenyl-2-picrylhydrazyl) assay. Total flavonoid and phenolic contents were determined using colorimetric assays. MTT assay was used to estimate the antiproliferative activities of the extracts against human hepatoma (HepG2) cancer cell line. In addition, the effects of R. stricta extract on cell cycle, colony formation, and wound healing of HepG2 cells and tube formation of HUVEC cells were assessed. RESULTS: Percentage inhibition of DPPH scavenging activity were dose-dependent and ranged between (89.9% ± 0.51) and (28.6% ± 2.07). Phenolic contents ranged between (11.5 ± 0.013) and (9.7 ± 0.008) mg GAE/g while flavonoid content ranged between (20.8 ± 0.40) and (0.12 ± 0.0.01) mg QE/g. Antiproliferative results of the extracts were found to be consistent with their antioxidant activity. Among the extracts evaluated, that of R. stricta showed the best antioxidant, antiproliferative and antimetastatic activities at low concentration. It also inhibited the colony-formation capacity of HepG2 cells and exhibited antiangiogenic activity. Cell cycle analysis showed significant arrest of cells at G2/M phase 12 and 48 h after treatment and significant arrest at G1/S phase after 24 h of treatment. Consistent data were observed in western blot analysis of protein levels of Cdc2 and its cyclin partners. CONCLUSIONS: These findings introduce R. stricta as a potentially useful anti-metastatic agent and a novel potential anti-tumour agent for hepatocellular carcinoma (HCC) treatment.


Asunto(s)
Antineoplásicos , Antioxidantes , Fabaceae/química , Extractos Vegetales , Antineoplásicos/química , Antineoplásicos/farmacología , Antioxidantes/química , Antioxidantes/farmacología , Compuestos de Bifenilo/metabolismo , Supervivencia Celular/efectos de los fármacos , Flavonoides/análisis , Células Hep G2 , Células Endoteliales de la Vena Umbilical Humana , Humanos , Medicina Tradicional , Fenoles/análisis , Picratos/metabolismo , Extractos Vegetales/química , Extractos Vegetales/farmacología , Hojas de la Planta/química , Plantas Medicinales/química
2.
Hemoglobin ; 38(1): 56-9, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24205932

RESUMEN

In populations with high prevalences of iron deficiency and thalassemia trait, many apparently healthy individuals have abnormal erythroid parameters, which may cause diagnostic problems in clinical practice. We studied the prevalence and causes of red cell parameter values outside their reference ranges in 394 healthy individuals of Bedouin Arab origin, who had complete blood counts (CBCs), hemoglobin (Hb) analyses and serum ferritin tests done. Their mean age ± standard deviation (SD) was 24.8 ± 4.9 years and 51.8% were females. Overall, 53.0% (209/394) had low Hb, MCV or MCH or high RDW. Anemia was present in 27.0% (55/204) of the women and 3.0% (6/190) of the men. Overall prevalence of MCV < 80.0 fL was 45.0% (176/394) and MCH < 27.0 pg was 48.0% (190/394); RDW > 14.0% was found in 21.0% (43/204) of women and 7.0% (14/190) of men. Of the women, 16.0% had iron deficiency anemia (33/204) and 65.0% had ferritin values of < 30.0 µg/L (133/204). The estimated prevalence of α-thalassemia (α-thal) trait in men was 32.0% (60/190) and that of ß-thalassemia (ß-thal) trait in both sexes was 3.0% (12/394). In conclusion, half of the healthy Emirati population have abnormal CBC values. For clinical purposes, they require reference standards for red cells that are derived from their own population. Screening of women for iron deficiency is justified due to a high prevalence of iron deficiency.


Asunto(s)
Índices de Eritrocitos , Hemoglobinopatías/sangre , Hemoglobinopatías/diagnóstico , Adolescente , Adulto , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Persona de Mediana Edad , Guías de Práctica Clínica como Asunto/normas , Estándares de Referencia , Emiratos Árabes Unidos , Adulto Joven
3.
ScientificWorldJournal ; 2012: 698597, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22778703

RESUMEN

We describe the baseline characteristics, management, and in-hospital outcomes of patients in the United Arab Emirates (UAE) with DM admitted with an acute coronary syndrome (ACS) and assess the influence of DM on in-hospital mortality. Data was analyzed from 1697 patients admitted to various hospitals in the UAE with a diagnosis of ACS in 2007 as part of the 1st Gulf RACE (Registry of Acute Coronary Events). Of 1697 patients enrolled, 668 (39.4%) were diabetics. Compared to patients without DM, diabetic patients were more likely to have a past history of coronary artery disease (49.1% versus 30.1%, P < 0.001), hypertension (67.2% versus 36%, P < 0.001), and prior revascularization (21% versus 11.4%, P < 0.001). They experienced more in-hospital recurrent ischemia (8.5% versus 5.1%; P = 0.004) and heart failure (20% versus 10%; P < 0.001). The mortality rate was 2.7% for diabetics and 1.6% for nondiabetics (P = 0.105). After age adjustment, in-hospital mortality increased by 3.5% per year of age (P = 0.016). This mortality was significantly higher in females than in males (P = 0.04). ACS patients with DM have different clinical characteristics and appear to have poorer outcomes.


Asunto(s)
Síndrome Coronario Agudo/mortalidad , Síndrome Coronario Agudo/terapia , Diabetes Mellitus/mortalidad , Diabetes Mellitus/terapia , Hospitalización/estadística & datos numéricos , Comorbilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Pronóstico , Factores de Riesgo , Análisis de Supervivencia , Tasa de Supervivencia , Resultado del Tratamiento , Emiratos Árabes Unidos/epidemiología
4.
Org Biomol Chem ; 9(24): 8301-12, 2011 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-22042341

RESUMEN

Stable analogs of bacterial transferase MraY substrate or product with a pyrophosphate surrogate in their structure are described. ß-ketophosphonates were designed as pyrophosphate bioisosteres and were investigated as UDP-GlcNAc mimics. The developed strategy allows introduction of structural diversity at a late stage of the synthesis. The biological activity of the synthesized compounds was evaluated on the MraY enzyme.


Asunto(s)
Bacillus subtilis/enzimología , Proteínas Bacterianas/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Organofosfonatos/farmacología , Transferasas/antagonistas & inhibidores , Proteínas Bacterianas/metabolismo , Biocatálisis , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Conformación Molecular , Organofosfonatos/síntesis química , Organofosfonatos/química , Estereoisomerismo , Relación Estructura-Actividad , Transferasas/metabolismo , Transferasas (Grupos de Otros Fosfatos Sustitutos)
5.
Nutr J ; 10: 59, 2011 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-21619670

RESUMEN

BACKGROUND: This study was designed to determine the glycemic indices of five commonly used varieties of dates in healthy subjects and their effects on postprandial glucose excursions in individuals with type 2 diabetes mellitus. METHODS: Composition analysis was carried out for five types of dates (Tamer stage). The weights of the flesh of the dates equivalent to 50 g of available carbohydrates were calculated. The study subjects were thirteen healthy volunteers with a mean (± SD) age of 40.2 ± 6.7 years and ten participants with type 2 diabetes mellitus (controlled on lifestyle measures and/or metformin) with a mean HbA1c (± SD) of 6.6 ± (0.7%) and a mean age (± SD) of 40.8 ± 5.7 years. Each subject was tested on eight separate days with 50 g of glucose (on 3 occasions) and 50 g equivalent of available carbohydrates from the 5 varieties of date (each on one occasion). Capillary glucose was measured in the healthy subjects at 0, 15, 30, 45, 60, 90 and 120 min and for the diabetics at 0, 30, 60, 90, 120, 150 and 180 min. The glycemic indices were determined as ratios of the incremental areas under the response curves for the dates compared to glucose. Statistical analyses were performed using the Mann-Whitney U test and repeated measures analysis of variance. RESULTS: Mean glycemic indices ± SEM of the dates for the healthy individuals were 54.0 ± 6.1, 53.5 ± 8.6, 46.3 ± 7.1, 49.1 ± 3.6 and 55.1 ± 7.7 for Fara'd, Lulu, Bo ma'an, Dabbas and Khalas, respectively. Corresponding values for those with type 2 diabetes were very similar (46.1 ± 6.2, 43.8 ± 7.7, 51.8 ± 6.9, 50.2 ± 3.9 and 53.0 ± 6.0). There were no statistically significant differences in the GIs between the control and the diabetic groups for the five types of dates, nor were there statistically significant differences among the dates' GIs (df = 4, F = 0.365, p = 0.83). CONCLUSION: The results show low glycemic indices for the five types of dates included in the study and that their consumption by diabetic individuals does not result in significant postprandial glucose excursions. These findings point to the potential benefits of dates for diabetic subjects when used in a healthy balanced diet. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov NCT01307904.


Asunto(s)
Diabetes Mellitus Tipo 2/sangre , Dieta para Diabéticos , Carbohidratos de la Dieta/metabolismo , Frutas , Índice Glucémico , Adulto , Glucemia/análisis , Femenino , Humanos , Masculino , Persona de Mediana Edad , Periodo Posprandial , Emiratos Árabes Unidos
6.
Bioorg Med Chem ; 18(12): 4560-9, 2010 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-20537545

RESUMEN

New inhibitors of the bacterial transferase MraY are described. Their structure is based on an aminoribosyl-O-uridine like scaffold, readily obtained in two key steps. The amino group can be coupled with proline or guanylated. Alternatively, these amino, prolinyl or guanidinyl groups can be introduced through a triazole linker. Biological evaluation of these compounds on MraY from Bacillus subtilis revealed interesting inhibitory activity for both amino compounds.


Asunto(s)
Antibacterianos/síntesis química , Proteínas Bacterianas/antagonistas & inhibidores , Inhibidores Enzimáticos/síntesis química , Transferasas/antagonistas & inhibidores , Antibacterianos/química , Antibacterianos/farmacología , Bacillus subtilis/enzimología , Proteínas Bacterianas/metabolismo , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Transferasas/metabolismo , Transferasas (Grupos de Otros Fosfatos Sustitutos) , Triazoles/síntesis química , Triazoles/química , Triazoles/farmacología
7.
Biophys J ; 97(5): 1390-7, 2009 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-19720027

RESUMEN

We investigated the specificity of interaction of a new type A lantibiotic, clausin, isolated from Bacillus clausii, with lipid intermediates of bacterial envelope biosynthesis pathways. Isothermal calorimetry and steady-state fluorescence anisotropy (with dansylated derivatives) identified peptidoglycan lipids I and II, embedded in dodecylphosphocholine micelles, as potential targets. Complex formation with dissociation constants of approximately 0.3 muM and stoichiometry of approximately 2:1 peptides/lipid intermediate was observed. The interaction is enthalpy-driven. For the first time, to our knowledge, we evidenced the interaction between a lantibiotic and C(55)-PP-GlcNAc, a lipid intermediate in the biosynthesis of other bacterial cell wall polymers, including teichoic acids. The pyrophosphate moiety of these lipid intermediates was crucial for the interaction because a strong binding with undecaprenyl pyrophosphate, accounting for 80% of the free energy of binding, was observed. No binding occurred with the undecaprenyl phosphate derivative. The pentapeptide and the N-acetylated sugar moieties strengthened the interaction, but their contributions were weaker than that of the pyrophosphate group. The lantibiotic decreased the mobility of the pentapeptide. Clausin did not interact with the water-soluble UDP-MurNAc- and pyrophosphoryl-MurNAc-pentapeptides, pointing out the importance of the hydrocarbon chain of the lipid target.


Asunto(s)
Bacterias/metabolismo , Bacteriocinas/metabolismo , Pared Celular/metabolismo , Bacillus/aislamiento & purificación , Bacillus/metabolismo , Bacteriocinas/aislamiento & purificación , Calorimetría , Compuestos de Dansilo/metabolismo , Fluorescencia , Polarización de Fluorescencia , Cinética , Monosacáridos/metabolismo , Movimiento (Física) , Oligopéptidos/metabolismo , Fosfatos de Poliisoprenilo/metabolismo , Unión Proteica , Rotación , Termodinámica , Factores de Tiempo , Uridina Difosfato Ácido N-Acetilmurámico/análogos & derivados , Uridina Difosfato Ácido N-Acetilmurámico/metabolismo
8.
Anal Biochem ; 391(2): 163-5, 2009 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-19442646

RESUMEN

The WecA transferase is an integral membrane protein and a member of the polyprenyl phosphate N-acetylhexosamine-1-phosphate transferase superfamily. It initiates the biosynthesis of various bacterial cell envelope components such as the lipopolysaccharide O-antigen. We report on the first large-scale enzymatic synthesis, purification, and characterization of the undecaprenyl-pyrophosphoryl-N-acetylglucosamine product of the WecA transferase. This is an essential lipid intermediate for the biosynthesis of various bacterial cell envelope components. Its availability in a pure form will allow the biochemical and structural characterization of the various enzymes requiring it as a substrate for the synthesis of cell wall polymers.


Asunto(s)
Acetilglucosamina/análogos & derivados , Proteínas de Escherichia coli/metabolismo , Fosfatos de Poliisoprenilo/biosíntesis , Polímeros/metabolismo , Transferasas (Grupos de Otros Fosfatos Sustitutos)/metabolismo , Acetilglucosamina/biosíntesis , Acetilglucosamina/aislamiento & purificación , Biocatálisis , Pared Celular/metabolismo , Fosfatos de Poliisoprenilo/aislamiento & purificación , Polímeros/química , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
9.
BMC Chem ; 13(1): 106, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31428743

RESUMEN

Cannabis products (marijuana, weed, hashish) are among the most widely abused psychoactive drugs in the world, due to their euphorigenic and anxiolytic properties. Recently, hair analysis is of great interest in analytical, clinical, and forensic sciences due to its non-invasiveness, negligible risk of infection and tampering, facile storage, and a wider window of detection. Hair analysis is now widely accepted as evidence in courts around the world. Hair analysis is very feasible to complement saliva, blood tests, and urinalysis. In this review, we have focused on state of the art in hair analysis of cannabis with particular attention to hair sample preparation for cannabis analysis involving pulverization, extraction and screening techniques followed by confirmatory tests (e.g., GC-MS and LC-MS/MS). We have reviewed the literature for the past 10 years' period with special emphasis on cannabis quantification using mass spectrometry. The pros and cons of all the published methods have also been discussed along with the prospective future of cannabis analysis.

10.
BMC Res Notes ; 12(1): 3, 2019 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-30602390

RESUMEN

OBJECTIVES: The present study aimed at determining the antioxidant activity, total phenols and flavonoids and to evaluate the antiproliferative activity of ethanolic extract of Matricaria recutita L. (chamomile). The antioxidant activities were measured using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay. The total phenolic content was measured by the Folin-Ciocalteu assay. The flavonoid content was determined using the aluminum chloride method. The MTT assay was used to estimate the antiproliferative activities against human hepatoma (HepG2) cancer cell line. We assessed the mode of action of the extract as a cancer preventive agent and reported its ability to regulate tumor angiogenesis by down regulating in a dose dependent manner the expression of some proteins involved in the process. RESULTS: The percentage inhibition of DPPH scavenging activity was dose-dependent ranging between (94.8% ± 0.03) at 1.50 mg/mL and (84.2% ± 0.86) at 0.15 mg/mL. It showed high polyphenols (21.4 ± 0.327 mg GAE/g) and high flavonoids content (157.9 ± 2.22 mg QE/g). Effect of extract was investigated against HepG2 cells. A dose-dependent reduction in cell viability was recorded in cells treated with the extract. The IC50 was ~ 300 µg/mL. It significantly inhibited the level of important prerequisite angiogenesis markers both in HepG2 cells and ex vivo.


Asunto(s)
Antineoplásicos/farmacología , Antioxidantes/farmacología , Flores , Matricaria , Extractos Vegetales/farmacología , Animales , Etanol , Células Hep G2 , Humanos , Masculino , Ratas , Ratas Wistar
11.
J Bacteriol ; 190(21): 7141-6, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18723618

RESUMEN

To date, the structural and functional characterization of proteins belonging to the polyprenyl-phosphate N-acetylhexosamine-1-phosphate transferase superfamily has been relentlessly held back by problems encountered with their overexpression and purification. In the present work and for the first time, the integral membrane protein WecA that catalyzes the transfer of the GlcNAc-1-phosphate moiety from UDP-GlcNAc onto the carrier lipid undecaprenyl phosphate, yielding undecaprenyl-pyrophosphoryl-GlcNAc, the lipid intermediate involved in the synthesis of various bacterial cell envelope components, was overproduced and purified to near homogeneity in milligram quantities. An enzymatic assay was developed, and the kinetic parameters of WecA as well as the effects of pH, salts, cations, detergents, and temperature on the enzyme activity were determined. A minimal length of 35 carbons was required for the lipid substrate, and tunicamycin was shown to inhibit the enzyme at submicromolar concentrations.


Asunto(s)
Proteínas de Escherichia coli/aislamiento & purificación , Proteínas de Escherichia coli/metabolismo , Transferasas (Grupos de Otros Fosfatos Sustitutos)/aislamiento & purificación , Transferasas (Grupos de Otros Fosfatos Sustitutos)/metabolismo , Electroforesis en Gel de Poliacrilamida , Activación Enzimática/efectos de los fármacos , Proteínas de Escherichia coli/genética , Concentración de Iones de Hidrógeno , Sales (Química)/farmacología , Especificidad por Sustrato , Transferasas (Grupos de Otros Fosfatos Sustitutos)/genética , Tunicamicina/farmacología
12.
Biochemistry ; 47(34): 8919-28, 2008 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-18672909

RESUMEN

The MraY transferase is an integral membrane protein that catalyzes an essential step of peptidoglycan biosynthesis, namely the transfer of the phospho-N-acetylmuramoyl-pentapeptide motif onto the undecaprenyl phosphate carrier lipid. It belongs to a large superfamily of eukaryotic and prokaryotic prenyl sugar transferases. No 3D structure has been reported for any member of this superfamily, and to date MraY is the only protein that has been successfully purified to homogeneity. Nineteen polar residues located in the five cytoplasmic segments of MraY appeared as invariants in the sequences of MraY orthologues. A certain number of these invariant residues were found to be conserved in the whole superfamily. To assess the importance of these residues in the catalytic process, site-directed mutagenesis was performed using the Bacillus subtilis MraY as a model. Fourteen residues were shown to be essential for MraY activity by an in vivo functional complementation assay using a constructed conditional mraY mutant strain. The corresponding mutant proteins were purified and biochemically characterized. None of these mutations did significantly affect the binding of the nucleotidic and lipidic substrates, but the k cat was dramatically reduced in almost all cases. The important residues for activity therefore appeared to be distributed in all the cytoplasmic segments, indicating that these five regions contribute to the structure of the catalytic site. Our data show that the D98 residue that is invariant in the whole superfamily should be involved in the deprotonation of the lipid substrate during the catalytic process.


Asunto(s)
Bacillus subtilis/metabolismo , Proteínas Bacterianas/metabolismo , Peptidoglicano/biosíntesis , Transferasas (Grupos de Otros Fosfatos Sustitutos)/metabolismo , Transferasas/metabolismo , Secuencia de Aminoácidos , Bacillus subtilis/enzimología , Bacillus subtilis/genética , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Sitios de Unión , Activación Enzimática/efectos de los fármacos , Prueba de Complementación Genética , Concentración de Iones de Hidrógeno , Cloruro de Magnesio/farmacología , Modelos Biológicos , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Mutación , Transferasas/química , Transferasas/genética , Transferasas (Grupos de Otros Fosfatos Sustitutos)/química , Transferasas (Grupos de Otros Fosfatos Sustitutos)/genética , Transformación Genética
13.
J Steroid Biochem Mol Biol ; 180: 118-128, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29432962

RESUMEN

Research shows that immunoassay techniques are not the best choice for the estimation of vitamin D in human blood samples. The main reasons are that some immunoassays are not able to distinguish between 25-OHD3 and 25-OHD2 vitamin D metabolites. Furthermore, immunoassays cannot differentiate between 25OHD and inactive epimers of vitamin D. Vitamin D epimers and isobars have been known to overlap with the 25OHD signals and give false positives when tested. Liquid chromatography tandem-mass spectrometry (LC-MS/MS) can differentiate between 25OHD3 and 25OHD2. Separating epimers and isobars (which have the same molecular weight) from vitamin D is achieved through chromatographic separation from actual 25OHD peaks, although this could also cause inaccuracies in vitamin D measurements. The main aim of this study was to develop and validate an improved LC-MS/MS method (using a Shimadzu 8060 system) that could accurately detect and quantitate up to 10 different metabolites of vitamin D, as well as differentiate the epimers and isobars. The secondary aim was to apply the developed LC-MS/MS method for the accurate measurement of blood vitamin D levels in the Emirati population. The Shimadzu 8060 system was run using positive ion electrospray ionization (ESI) in Dynamic Multiple Reaction Monitoring (DMRM) mode for quantification. The method involved blood sample collection from 80 Emirati volunteers, followed by serum extraction and liquid-liquid extraction. The chromatography column used for the analysis was an Ascentis Express F5. Precursor and product ions were detected using a Shimadzu 8060 LC-MS/MS system, and 10 metabolites of vitamin D were detected and quantified, including epimers and isobars. The method validation showed good sensitivity, recovery, linearity, precision, specificity, and accuracy. Furthermore, the data showed that vitamin D epimer 3-epi-25OHD and isobar 7-α-hydroxy-4-cholesten-3-one (7αC4) accounted for a significant portion of vitamin D results in the Emirati population. We report a more reliable, reproducible, and robust LC-MS/MS method for the accurate detection of 25OHD (vitamin D) in the Emirati population. The method has the capacity to detect and separate 10 metabolites of vitamin D as well as separate 25OHD from co-eluting epimers and isobars. The method has also been successfully implemented in gauging vitamin D deficiency in the Emirati population. Thus, this improved LC-MS/MS method could prove very useful in accurately estimating the levels of vitamin D in the Emirati population and in further clinical studies.


Asunto(s)
Biomarcadores/sangre , Cromatografía Liquida/métodos , Espectrometría de Masas en Tándem/métodos , Deficiencia de Vitamina D/diagnóstico , Vitamina D/sangre , Vitaminas/sangre , Adulto , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Persona de Mediana Edad , Emiratos Árabes Unidos/epidemiología , Deficiencia de Vitamina D/sangre , Deficiencia de Vitamina D/epidemiología , Adulto Joven
14.
Biochimie ; 127: 249-57, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27312048

RESUMEN

The MraY transferase catalyzes the first membrane step of bacterial cell wall peptidoglycan biosynthesis, namely the transfer of the N-acetylmuramoyl-pentapeptide moiety of the cytoplasmic precursor UDP-MurNAc-pentapeptide to the membrane transporter undecaprenyl phosphate (C55P), yielding C55-PP-MurNAc-pentapeptide (lipid I). A paralogue of MraY, WecA, catalyzes the transfer of the phospho-GlcNAc moiety of UDP-N-acetylglucosamine onto the same lipid carrier, leading to the formation of C55-PP-GlcNAc that is essential for the synthesis of various bacterial cell envelope components. These two enzymes are members of the polyprenyl-phosphate N-acetylhexosamine 1-phosphate transferase superfamily, which are essential for bacterial envelope biogenesis. Despite the availability of detailed biochemical information on the MraY enzyme, and the recently published crystal structure of MraY of Aquifex aeolicus, the molecular basis for its catalysis remains poorly understood. This knowledge can contribute to the design of potential inhibitors. Here, we report a detailed catalytic study of the Bacillus subtilis MraY and Thermotoga maritima WecA transferases. Both forward and reverse exchange reactions required the presence of the second substrate, C55P and uridine monophosphate (UMP), respectively. Both enzymes did not display any pyrophosphatase activity on the nucleotide substrate. Moreover, we showed that the nucleotide substrate UDP-MurNAc-pentapeptide, as well as the nucleotide product UMP, can bind to MraY in the absence of lipid ligands. Therefore, our data are in favour of a single displacement mechanism. During this "one-step" mechanism, the oxyanion of the polyprenyl-phosphate attacks the ß-phosphate of the nucleotide substrate, leading to the formation of lipid product and the liberation of UMP. The involvement of an invariant aspartyl residue in the deprotonation of the lipid substrate is discussed.


Asunto(s)
Bacillus subtilis/enzimología , Biocatálisis , Homología de Secuencia de Aminoácido , Thermotoga maritima/enzimología , Transferasas/metabolismo , Aminas/farmacología , Metabolismo de los Lípidos , Especificidad por Sustrato , Transferasas/antagonistas & inhibidores , Transferasas/química
15.
World J Gastroenterol ; 21(2): 644-52, 2015 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-25593494

RESUMEN

AIM: To measure biochemical parameters in stomach biopsies and test their suitability as diagnostic biomarkers for gastritis and precancerous lesions. METHODS: Biopsies were obtained from the stomachs of two groups of patients (n = 40) undergoing fiber-optic endoscopy due to upper gastrointestinal symptoms. In the first group (n = 17), only the corpus region was examined. Biopsies were processed for microscopic examination and measurement of mitochondrial O2 consumption (cellular respiration), cellular adenosine triphosphate (ATP), glutathione (GSH), and caspase activity. In the second group of patients (n = 23), both corpus and antral regions were studied. Some biopsies were processed for microscopic examination, while the others were used for measurements of cellular respiration and GSH level. RESULTS: Microscopic examinations of gastric corpus biopsies from 17 patients revealed normal mucosae in 8 patients, superficial gastritis in 7 patients, and chronic atrophic gastritis in 1 patient. In patients with normal histology, the rate (mean ± SD) of cellular respiration was 0.17 ± 0.02 µmol/L O2 min(-1) mg(-1), ATP content was 487 ± 493 pmol/mg, and GSH was 469 ± 98 pmol/mg. Caspase activity was detected in 3 out of 8 specimens. The values of ATP and caspase activity were highly variable. The presence of superficial gastritis had insignificant effects on the measured biomarkers. In the patient with atrophic gastritis, cellular respiration was high and ATP was relatively low, suggesting uncoupling oxidative phosphorylation. In the second cohort of patients, the examined biopsies showed either normal or superficial gastritis. The rate of cellular respiration (O2. µmol/L min(-1) mg(-1)) was slightly higher in the corpus than the antrum (0.18 ± 0.05 vs 0.15 ± 0.04, P = 0.019). The value of GSH was about the same in both tissues (310 ± 135 vs 322 ± 155, P = 0.692). CONCLUSION: The corpus mucosa was metabolically more active than the antrum tissue. The data in this study will help in understanding the pathophysiology of gastric mucosa.


Asunto(s)
Caspasas/metabolismo , Metabolismo Energético , Gastritis Atrófica/enzimología , Glutatión/metabolismo , Estómago/enzimología , Adenosina Trifosfato/metabolismo , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Apoptosis , Biomarcadores/metabolismo , Biopsia , Respiración de la Célula , Endoscopía Gastrointestinal , Estudios de Factibilidad , Femenino , Mucosa Gástrica/enzimología , Gastritis Atrófica/diagnóstico , Humanos , Masculino , Persona de Mediana Edad , Consumo de Oxígeno , Valor Predictivo de las Pruebas , Estudios Prospectivos , Antro Pilórico/enzimología , Estómago/patología , Adulto Joven
16.
Angiology ; 65(7): 585-9, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23921507

RESUMEN

We investigated the association between in-hospital and peri-hospital mortality and body mass index (BMI)/waist circumference (WC) in a prospective acute coronary syndrome (ACS) registry in the Arabian Gulf. No significant associations with in-hospital mortality were found. Normal BMI had highest peri-hospital mortality, notably those with high WC. In logistic regression of mortality on obesity measures and potential confounders, the effects of obesity measures were no longer significant. In-hospital death increased by 5% with age and decreased by 42% in males. Mortality increased 3.7-fold with ST-elevation myocardial infarction (STEMI) and 3.0-fold with heart failure (HF) but decreased by 33% with dyslipidemia. Peri-hospital death increased by 4% with age and decreased by 30% in males. Mortality increased 2.8-fold with STEMI and 2.4-fold with HF. In- and peri-hospital mortality in ACS is significantly associated with age, gender, STEMI, HF, and dyslipidemia but not obesity measures.


Asunto(s)
Síndrome Coronario Agudo/mortalidad , Síndrome Coronario Agudo/terapia , Índice de Masa Corporal , Obesidad/mortalidad , Obesidad/terapia , Síndrome Coronario Agudo/complicaciones , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Femenino , Mortalidad Hospitalaria , Hospitalización/estadística & datos numéricos , Humanos , Masculino , Persona de Mediana Edad , Obesidad/complicaciones , Estudios Prospectivos , Sistema de Registros , Factores de Riesgo , Caracteres Sexuales
17.
BMC Pharmacol Toxicol ; 14: 15, 2013 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-23448291

RESUMEN

Atorvastatin (a 3-hydroxy-3-methylglutaryl coenzyme-A reductase inhibitor) is a widely used cholesterol-lowering drug, which is recognized for its potential hepatotoxicity. This study investigated in vitro effects of this agent on hepatic tissue respiration, ATP content, caspase activity, urea synthesis and histology. Liver fragments from Taylor Outbred and C57Bl/6 mice were incubated at 37°C in Krebs-Henseleit buffer continuously gassed with 95% O2: 5% CO2 in the presence and absence of atorvastatin. Phosphorescence O2 analyzer that measured dissolved [O2] as a function of time was used to monitor cellular mitochondrial O2 consumption. The caspase-3 substrate N-acetyl-asp-glu-val-asp-7-amino-4-methylcoumarin was used to monitor caspase activity. The rates of hepatocyte respiration (µM O2 min(-1) mg(-1)) in untreated samples were 0.15±0.07 (n=31). The corresponding rates for samples treated with 50 nM (therapeutic concentration), 150 nM or 1.0 µM atorvastatin for ≤13 h were 0.13±0.05 (n=19), p=0.521. The contents of hepatocyte ATP (pmol(-1) mg(-1)) in untreated samples were 40.3±14.0 and in samples treated with 1.0 µM atorvastatin for ≤4.5 h were 48.7±23.9 (p=0.7754). The concentrations of urea (mg/dL mg(-1), produced over 50 min) for untreated samples were 0.061±0.020 (n=6) and for samples treated with 1.0 µM atorvastatin for ≤6 h were 0.072±0.022 (n=6), p=0.3866. Steadily, hepatocyte caspase activity and histology were unaffected by treatments with up to 1.0 µM atorvastatin for ≤6 h. Thus, the studied murine model showed preserved hepatocyte function and structure in the presence of high concentrations of atorvastatin.


Asunto(s)
Hepatocitos/efectos de los fármacos , Ácidos Heptanoicos/farmacología , Inhibidores de Hidroximetilglutaril-CoA Reductasas/farmacología , Hígado/efectos de los fármacos , Pirroles/farmacología , Adenosina Trifosfato/metabolismo , Animales , Atorvastatina , Caspasas/metabolismo , Metabolismo Energético , Hepatocitos/metabolismo , Técnicas In Vitro , Hígado/anatomía & histología , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Oxígeno/metabolismo , Urea/metabolismo
18.
BMC Res Notes ; 6: 70, 2013 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-23442607

RESUMEN

BACKGROUND: The aim of this study was to develop liver tissue preparation suitable for investigating toxins. Hepatocyte respiration, ATP content, urea synthesis, caspase activity and morphology were measured as a function of in vitro incubation time. Mice were anesthetized by sevoflurane inhalation. Small liver fragments were then rapidly excised and incubated at 37°C in Krebs-Henseleit buffer (continuously gassed with 95% O2: 5% CO2) for up to 6 h. Phosphorescence O2 analyzer was used to determine the rate of cellular mitochondrial O2 consumption (kc, µM O2 min-1 mg-1). Cellular ATP was measured using the luciferin/luciferase system. The caspase-3 substrate N-acetyl-asp-glu-val-asp-7-amino-4-methylcoumarin (Ac-DEVD-AMC) was used to monitor intracellular caspase activity; cleaved AMC moieties (reflecting caspase activity) were separated on HPLC and detected by fluorescence. FINDINGS: Respiration was inhibited by cyanide, confirming the oxidation occurred in the respiratory chain. The values of kc (mean ± SD) for 0≤ t ≤6 h were 0.15 ± 0.02 µM O2 min-1 mg-1 (n = 18, coefficient of variation, CV = 13%), ATP content 131 ± 69 pmol mg-1 (1≤ t ≤6 h, n = 16, CV = 53%), synthesized urea 0.134 ± 0.017 mg/dL mg-1 in 50 min (0≤ t ≤6 h, n = 14, CV = 13%), and AMC peak area 62,540 ± 26,227 arbitrary units mg-1 (1≤ t ≤6 h, n = 3, CV = 42%). Hepatocyte morphology and organelles were reasonably persevered. CONCLUSIONS: The described liver tissue preparation demonstrates stable hepatocyte structure, ultrastructure and biomarkers for up to 6 h, permitting in vitro studies.


Asunto(s)
Hígado/efectos de los fármacos , Pruebas de Toxicidad , Adenosina Trifosfato/metabolismo , Animales , Caspasa 3/metabolismo , Cromatografía Líquida de Alta Presión , Metabolismo Energético , Técnicas In Vitro , Masculino , Ratones , Ratones Endogámicos C57BL , Mitocondrias Hepáticas/enzimología , Mitocondrias Hepáticas/metabolismo , Consumo de Oxígeno , Espectrometría de Fluorescencia
19.
Asia Pac J Clin Nutr ; 22(4): 565-73, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24231017

RESUMEN

The consumption of dates with coffee is common among Arabs and may affect postprandial hyperglycemia ex-cursion. The study aimed to determine the effect of coffee on the glycemic index of a common variety of dates (Khalas) tested in healthy and type 2 diabetes mellitus individuals. Study subjects were thirteen healthy volunteers (mean age: 40.2±6.7 years) and ten diabetic participants with a mean HbA1c of 6.6±(0.7%) and a mean age of 40.8±5.7 years. Each subject participated in five days of tests with 50 g of glucose and 50 g equivalent of available carbohydrates from the dates (with/without coffee). Capillary glucose was measured in the healthy subjects at 0, 15, 30, 45, 60, 90 and 120 min, and for the diabetics at 0, 30, 60, 90, 120, 150 and 180 min. Glycemic indices were determined as ratios of the incremental areas under the response curves for the interventions. Statistical analyses were performed using the independent samples and paired t-tests. Mean±SE glycemic indices of the Khalas dates for the healthy individuals were 55.1±7.7 and 52.7±6.2 without and with coffee consumption, respectively. Similar values were observed for those with diabetes (53.0±6.0 and 41.5±5.4). Differences between glycemic indices of Khalas with or without coffee were not significant (p=0.124). There were no significant differences in glycemic index between the diabetic and healthy subjects (p=0.834 and p=0.202 without and with coffee respectively). In conclusion, at least in the short term, coffee does not adversely affect capillary glucose levels following Khalas dates consumption in healthy and diabetic volunteers.


Asunto(s)
Arecaceae/química , Cafeína/administración & dosificación , Café , Diabetes Mellitus Tipo 2/sangre , Frutas/química , Índice Glucémico/efectos de los fármacos , Adulto , Glucemia/análisis , Carbohidratos de la Dieta/efectos adversos , Femenino , Hemoglobina Glucada/análisis , Humanos , Hiperglucemia/prevención & control , Masculino , Persona de Mediana Edad
20.
Angiology ; 64(1): 9-14, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22569405

RESUMEN

Gender differences exist in many aspects of acute coronary syndrome (ACS), including presentation and delay in diagnosis and treatment. The aim of the study was to evaluate gender-related differences in ACS patients in the United Arab Emirates (UAE). We analyzed a subset (n = 1697) of the Gulf Registry of Acute Coronary Events (Gulf RACE) data collected in 2007 of patients with ACS from 18 UAE hospitals. Women were significantly older (mean age: 64.0 ± 12.4 years for females and 50.9 ± 10.6 years for males, P < .001), more often had cardiac risk factors and were significantly less treated with ß-blockers and reperfusion therapy. The adjusted mortality rate of women was 4.6% versus 1.2% in men (P < .001). Heart failure was higher in females compared with men (24.6% vs 12.5%; P < .001). Reasons for the high in-hospital mortality in women need to be investigated further.


Asunto(s)
Síndrome Coronario Agudo/diagnóstico , Síndrome Coronario Agudo/epidemiología , Síndrome Coronario Agudo/mortalidad , Femenino , Identidad de Género , Mortalidad Hospitalaria , Humanos , Masculino , Estudios Prospectivos , Factores de Riesgo , Factores Sexuales , Resultado del Tratamiento , Emiratos Árabes Unidos/epidemiología
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