Desenvolvimento e caracterização de lipossomas peguilados para veiculação de L-asparaginase / Development and characterization of peg-grafted liposomes for lasparaginase encapsulation

A Leucemia Linfoide Aguda (LLA) é um câncer de maior incidência em crianças, e tem a Lasparaginase (ASNase) como fármaco amplamente utilizado no tratamento dos afetados. A ASNase catalisa a hidrólise do aminoácido L-asparagina (Asn), presente na corrente sanguínea, a ausência do aminoácido no meio extracelular leva à morte células leucêmicas, que necessitam deste aminoácido para as funções celulares. Fatores envolvendo a eficiência do tratamento com ASNase como reações adversas e curta meia-vida, principalmente devido ao reconhecimento pelo sistema imune e degradação por proteases, limitam a sua eficácia. A encapsulação da enzima em lipossomas pode conferir proteção à degradação, melhorar seu perfil farmacocinético e diminuir os efeitos adversos, de forma a melhorar o tratamento da LLA sendo este o objetivo desse trabalho. Lipossomas de DOPC (1,2-dioleoil-sn-glicero-3-fosfocolina) e DMPC (1,2-dimiristoil-snglicero-3-fosfocolina) foram desenvolvidos empregando-se o método de hidratação do filme lipídico e diferentes protocolos de preparo contendo ou não diferentes concentrações de 18:0 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polietilenogicol)-2000] (DSPE-PEG). Os lipossomas produzidos foram utilizados para encapsular a ASNase e os sistemas contendo ou não ASNase encapsulada foram caracterizados por espalhamento de luz dinâmico (DLS), potencial zeta, microscopia eletrônica de transmissão (MET) e criomicroscopia de transmissão. Adicionalmente, foram avaliados a taxa de encapsulação e o perfil de permeabilidade das vesículas à L-asparagina. As análises de DLS mostraram que as nanoestruturas formadas empregando-se agitação magnética a partir de sistemas contendo 10% e 20% de DSPE-PEG possuem diâmetro hidrodinâmico menor (~ 25 nm a 60 nm) que os mesmos sistemas sem o fosfolipídio peguilado (~190 nm a 222 nm), demonstrando a relação entre a diminuição do tamanho e o aumento da quantidade de fosfolipídio peguilado e possível formação de estruturas micelares ou bicelares. O emprego de agitação em vórtex para hidratação do filme lipídico, adição do antioxidante -tocoferol e redução da concentração de DSPE-PEG (5% e 10%) levou à formação de sistemas com diâmetro hidrodinâmico maior, sendo esse protocolo e concentrações de PEG definidos como padrão. As análises de MET comprovaram a formação de lipossomas com diâmetro hidrodinâmico semelhante ao observado por DLS; com a utilização da criomicroscopia foi possível observar os lipossomas sem deformações. Os lipossomas de DMPC/DSPE-PEG 10% apresentaram maior permeabilidade à L-asparagina ao longo do tempo e, portanto, poderiam funcionar como nanoreatores, depletando o aminoácido da circulação. Estudos in vitro com células tumorais devem ser realizados e em seguida estudos in vivo, para confirmar este potencial

L-asparaginase (ASNase) is a first-choice drug, combined with other drugs, in therapeutic schemes to treat Acute Lymphoblastic Leukemia (ALL) in children and adolescents. ASNase catalyzes the hydrolysis of L-asparagine (Asn) in the bloodstream; since ALL cells cannot synthesize this amino acid, protein synthesis is impaired leading to leukemic cells death by apoptosis. In spite of its therapeutic importance, treatment with ASNase is associated to side effects, mainly hypersensitivity and immunogenicity. Another drawback refers to degradation by plasma proteases that altogether with immunogenicity shortens the enzyme half-life. Encapsulation of ASNase in liposomes, vesicular nanostructures formed by the self-aggregation of phospholipids, is an attractive alternative that possibly will protect the enzyme from plasma proteases, resulting on better pharmacokinetics profile. In this work, we prepared by thin film hydration liposomal formulations of the phospholipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or 1,2-dimyristoyl-sn-glycero-3- phosphocholine (DMPC) containing or not different concentrations of 18:0 1,2-distearoyl-snglycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG), and encapsulated ASNase by electroporation. The systems containing or not ASNase were analyzed by Dynamic Light Scattering, zeta potential and Electron Microscopy. The encapsulation efficiency and vesicles permeability were also evaluated. According to the DLS analysis, the nanostructures formed by film hydration under magnetic stirring employing 10% or 20% DSPE-PEG presented smaller hydrodynamic diameter (~ 25 nm to 60 nm) than the same systems without the pegylated phospholipid (~ 190 nm to 222 nm), demonstrating the relation between size and the amount of pegylated phospholipid that results in formation of micellar or bicellar structures. The protocol was stabilize by hydration of the lipid film under vortex agitation, addition of the antioxidant - tocopherol and reduction of the concentration of DSPE-PEG (5% and 10%), what altogether led to the formation of nanostructures of higher hydrodynamic diameter and monodisperse systems. TEM analyzes confirmed the formation of liposomes with hydrodynamic diameter similar to that observed by DLS; with the use of cryomicroscopy it was possible to observe the liposomes without deformations. Liposomes of DMPC/DSPE-PEG 10% showed permeability to L-asparagine over time and, therefore, could function as nanoreactors, depleting the circulating amino acid

Reacciones alérgicas por L-asparaginasa en niños con leucemia linfoide aguda / L-asparagibase allergic reactions in children with lymphoblastic acute leukemia

La L-asparaginasa es un medicamento utilizado en distintas fases de todos los protocolos de tratamiento actuales de la leucemia linfoide aguda (LLA). Se describen múltiples manifestaciones secundarias a la L asparaginasa entre las que las reacciones alérgicas son las más frecuente. Se estudiaron 144 niños con diagnóstico de LLA tratados en el Instituto de Hematología e Inmunología, entre 1998 y el 2013. En 30 pacientes (21 por ciento) se presentaron reacciones alérgicas, similar a lo descrito en la literatura. El 76,6 por ciento de ellos habían recibido una dosis acumulativa menor de 80 000 UI (media de 48 757) y el mayor número de las reacciones alérgicas (86,7 por ciento) se reportó entre las dosis 9 y 18 recibidas (media de 11 dosis). Se observó una mayor supervivencia en los enfermos que recibieron más dosis (19 - 26 dosis) (p = 0.003). La sobrevida libre de eventos fue también mayor en este grupo (p= 0.357)(AU)

ABSTRACT L-asparaginase is a medication used in different phases of all current treatment protocols for acute lymphoid leukemia. Multiple secondary manifestations to L- asparaginase are described, and allergic reactions are the most frequent. We studied 144 children with acute lymphoblastic leukemia treated at the Instituto de Hematología e Inmunología between 1998 and 2013. Thirty patients (21 percent) had allergic reactions, similar to what is described in literature; 76.6 percent of them had received a cumulative dose of less than 80 000 IU (average of 48 757); and the highest number of allergic reactions (86.7 percent) was reported between doses 9 and 18 received (mean of 11 doses). A greater global survival was observed in patients who received more doses (19 - 26 doses) (p=0.003). Event free survival was also higher in this group (p= 0.357)(AU)

Development of a UPLC-MS/MS method for the therapeutic monitoring of L-asparaginase

This study aimed to develop a UPLC-MS/MS method for determining plasma levels of L-aspartic acid and L-asparagine and the activity of L-asparaginase. L-aspartic acid, L-asparagine, and L-aspartic acid-2,3,3-d3 were extracted from human plasma by protein precipitation with sulfosalicylic acid (30%, v/v). The plasma samples were analyzed using an Imtakt Intrada amino acid analysis column with 25 mM ammonium formate and 0.5% formic acid in acetonitrile as the mobile phase with step gradient method at a flow rate of 0.5 mL/min. The injection volume was 5 µL, and the total run time was 15 min. Inter- and intra-batch accuracies (%) ranged from 96.62–106.0% for L-aspartic acid and 89.85–104.8%, for L-asparagine, and the coefficient of variation (CV%) did not exceed 7%. The validation results for L-aspartic acid and L-asparagine satisfied the specified criterion, however, the results for L-asparaginase activity assay showed a borderline validity. This study could be a foundation for further development of therapeutic drug monitoring systems using UPLC-MS/MS.

Eficacia y seguridad de L-asparaginasa erwinia y L-asparaginasa E. Coli pegilada en el tratamiento de pacientes con leucemia linfoblástica aguda que presentam hipersensibilidad a L-asparaginasa E. coli nativa / Efficacy and safety of L-asparaginase erwinia and L-asparaginase E. coli pegylated in the treatment of patients with acute lymphoblastic leukemia who are hypersensitive to L-asparaginase E. coli native

INTRODUÇÃO: Antecedentes: El presente dictamen expone la evaluación de tecnología de la eficacia y seguridad del uso de L-asparaginasa Erwinia y L-asparaginasa E. coli pegilada para el tratamiento de pacientes con leucemia linfoblástica aguda que presentan hipersensibilidad a L-asparaginasa E. coli nativa. Aspectos Generales: La leucemia es el tipo de cáncer más común en niños, representando aproximadamente el 30% de todos los tipos de cáncer diagnosticados en niños; siendo la leucemia linfoblástica aguda (LLA) uno de los dos tipos de leucemias más comunes. Adicionalmente, alrededor del 60% de todos los casos de LLA ocurre en pacientes menores de 20 años. Así, LLA es un tipo de leucemia de alta importancia dentro de población joven. Tecnología Sanitaria de Interés: Las células neoplásicas en la leucemia linfoblástica aguda (LLA) no sintetizan las cantidades necesarias del aminoácido L-asparagina; por lo que requieren de funtes externas (i.e., L-asparagina extracelular). La L-asparaginasa, es una enzima que cataliza la conversión de L-asparagina más agua, en ácido aspártico y amoniaco, ocasionando que los niveles de L-asparagina extracelular disminuyan; y que por los tanto las células d ela LLA no cuenten con L-asparagina extracelular. Así, estas células neoplásicas se quedan sin fuentes de L-asparagina, y no pueden sintetizar proteínas de gran imporancia para su supervivencia, ocasionando su muerte. METODOLOGÍA: Estrategia de Búsqueda: Se realizó una búsqueda de la literatura a la eficacia y seguridad del uso de L-asparaginasa Erwinia y L-asparaginasa E. coli pegilada para el tratamiento de pacientes niños y adultos con leucemia linfoblástica aguda que presentan hipersensibilidad a L-asparaginasa E. coli nativa. Esta búsqueda se realizó utilizando los meta-buscadores: Translating Research into Practice (TRIPDATABASE) Y National Library of Medicine (Pubmed-Medline). RESULTADOS: Sinopsis de la Evidencia: Se realizó la búsqueda bibliográfica y de evidencia científica hasta marzo del 2017 para el sustento del uso de L-asparaginasa Erwinia en el tratamiento de leucemia linfoblástica aguda en pacientes niños y adultos que presentan hipersensibilidad a L-asparaginasa E. coli nativa. Se presente la evidencia disponible según el tipo de publicación priorizada en los criterios de inclusión (i.e., GP, ETS, RS y ECA fase III), siendo los ensayos de fase III o en su defecto ensayos controlados y aleatorizados la principal considerada. CONCLUSIONES: El presente dictamen evaluó la mejor evidencia disponible hasta marco 2017 en relación al uso de L-asparaginasa Erwinia y L-asparaginasa E. coli pegilada para el tratamiento de pacientes niños, adolescentes, y adultos con leucemia linfoblástica aguda, que presentan hipersensibilidad a L-asparaginasa E. coli nativa. El Instituto de Tecnologías Sanitarias-IETSI, aprueba el uso de L-asparaginasa Erwinia como parte del esquema quimioterápico utilizada para el tratamiento de pacientes niños, adolescentes, y adultos con leucemia linfoblástica aguda, que presentan hipersensibilidad grado 2 o más a L-asparaginasa E. coli nativa. La vigencia de este dictamen preliminar es de dos años a partir de la fecha de publicación. Asimismo, el Instituto de Tecnologías Sanitarias-IETSI, no aprueba el uso de L-asparaginasa E. coli pegilada en el tratamiento de pacientes niños, adolescentes, y adultos con leucemia linfoblástica aguda, que presentan hipersensiblidad grado 2 o más a L-asparaginasa E. coli nativa.

Correlation Between Gastric Emptying and Gastric Adaptive Relaxation Influenced by Amino Acids

BACKGROUND/AIMS: Amino acids have many physiological activities. We report the correlation between gastric emptying and gastric adaptive relaxation using tryptophan and amino acids with a straight alkyl chain, hydroxylated chain, and branched chain. Here we sought to further clarify the correlation between gastric emptying and gastric adaptive relaxation by using other amino acids. METHODS: In Sprague-Dawley rats, gastric emptying was evaluated by a breath test using [1-¹³C] acetic acid. The expired ¹³CO₂ pattern, T(max), C(max), and AUC(120min) values were used as evaluation items. Gastric adaptive relaxation was evaluated in a barostat experiment. Individual amino acids (1 g/kg) were administered orally 30 minutes before each breath test or barostat test. RESULTS: L-phenylalanine and L-tyrosine did not influence gastric emptying. All other amino acids, ie, L-proline, L-histidine, L-cysteine, L-methionine, L-aspartic acid, L-glutamic acid, L-asparagine, L-arginine, L-glutamine, and L-lysine significantly delayed and inhibited gastric emptying. L-Cysteine and L-aspartic acid significantly enhanced and L-methionine and L-glutamine significantly inhibited gastric adaptive relaxation. L-Phenylalanine moved the balloon toward the antrum, suggesting strong contraction of the fundus. T(max) showed a significant positive correlation (r = 0.709), and C(max) and AUC(120min) each showed negative correlations (r = 0.613 and 0.667, respectively) with gastric adaptive relaxation. CONCLUSION: From the above findings, it was found that a close correlation exists between gastric emptying and adaptive relaxation, suggesting that enhanced gastric adaptive relaxation inhibits gastric emptying.

Optimization of asparaginase production from Zymomonas mobilis by continuous fermentation / Otimização da produção de asparaginase de Zymomonas mobilis por fermentação contínua

A asparaginase é uma enzima usada em tratamento clínico como agente quimioterapêutico e em tecnologia de alimentos na prevenção de formação de acrilamida em alimentos fritos e assados. Asparaginase é industrialmente produzida por micro-organismos, principalmente bactérias gram negativas. Zymomonas mobilis é uma bactéria gram negativa que utiliza glicose, frutose e sacarose como fonte de carbono e é conhecida por sua eficiência para produzir etanol, sorbitol, levana, ácido glicônico, e mais recentemente, tem despertado interesse no uso desse micro-organismo na produção de asparaginase. Este trabalho teve como objetivo otimizar a produção de asparaginase de Z. mobilis por fermentação contínua, pelo uso do delineamento experimental e da metodologia da superfície de resposta, testando as variáveis: sacarose, extrato de levedura e asparagina. A condição ótima alcançada, com produção de 117,45 UI L-1 foi na taxa de diluição 0,20 h-1, utilizando 0,5 g L-1 de extrato de levedura, 20 g L-1 de sacarose e 1,3 g L-1 de asparagina. Observou-se que a relação carbono:nitrogênio (1:0,025) exerceu forte influência na resposta da atividade de asparaginase. A utilização de Z. mobilis por fermentação contínua demonstrou ser uma alternativa promissora na produção biotecnológica da asparaginase.

Asparaginase is an enzyme used in clinical treatments as a chemotherapeutic agent and in food technology to prevent acrylamide formation in fried and baked foods. Asparaginase is industrially produced by microorganisms, mainly gram-negative bacteria. Zymomonas mobilis is a Gram-negative bacterium that utilizes glucose, fructose and sucrose as carbon source and has been known for its efficiency in producing ethanol, sorbitol, levan, gluconic acid and has recently aroused interest for asparaginase production. Current assay optimizes the production of Z. mobilis asparaginase by continuous fermentation using response surface experimental design and methodology. The studied variables comprised sucrose, yeast extract and asparagine. Optimized condition obtained 117.45 IU L-1 with dilution rate 0.20 h-1, yeast extract 0.5 g L-1, sucrose 20 g L-1 and asparagine 1.3 g L-1. Moreover, carbon:nitrogen ratio (1:0.025) strongly affected the response of asparaginase activity. The use of Z. mobilis by continuous fermentation has proved to be a promising alternative for the biotechnological production of asparaginase.

Three New Non-reducing Polyketide Synthase Genes from the Lichen-Forming Fungus Usnea longissima

Usnea longissima has a long history of use as a traditional medicine. Several bioactive compounds, primarily belonging to the polyketide family, have been isolated from U. longissima. However, the genes for the biosynthesis of these compounds are yet to be identified. In the present study, three different types of non-reducing polyketide synthases (UlPKS2, UlPKS4, and UlPKS6) were identified from a cultured lichen-forming fungus of U. longissima. Phylogenetic analysis of product template domains showed that UlPKS2 and UlPKS4 belong to group IV, which includes the non-reducing polyketide synthases with an methyltransferase (MeT) domain that are involved in methylorcinol-based compound synthesis; UlPKS6 was found to belong to group I, which includes the non-reducing polyketide synthases that synthesize single aromatic ring polyketides, such as orsellinic acid. Reverse transcriptase-PCR analysis demonstrated that UlPKS2 and UlPKS4 were upregulated by sucrose; UlPKS6 was downregulated by asparagine, glycine, and alanine.

Alterations of Amino Acid Level in Depressed Rat Brain

Amino-acid neurotransmitter system dysfunction plays a major role in the pathophysiology of depression. Several studies have demonstrated the potential of amino acids as a source of neuro-specific biomarkers could be used in future diagnosis of depression. Only partial amino acids such as glycine and asparagine were determined from certain parts of rats' brain included hippocampi and cerebral cortex in previous studies. However, according to systematic biology, amino acids in different area of brain are interacted and interrelated. Hence, the determination of 34 amino acids through entire rats' brain was conducted in this study in order to demonstrate more possibilities for biomarkers of depression by discovering other potential amino acids in more areas of rats' brain. As a result, 4 amino acids (L-aspartic acid, L-glutamine, taurine and gamma-amino-n-butyric acid) among 34 were typically identified as potentially primary biomarkers of depression by data statistics. Meanwhile, an antidepressant called Fluoxetine was employed to verify other potential amino acids which were not identified by data statistics. Eventually, we found L-alpha-amino-adipic acid could also become a new potentially secondary biomarker of depression after drug validation. In conclusion, we suggested that L-aspartic acid, L-glutamine, taurine, gamma-amino-n-butyric acid and L-alpha-amino-adipic acid might become potential biomarkers for future diagnosis of depression and development of antidepressant.

Identificación de Pseudomonas aeruginosa empleando el método del Número Más Probable / Identification of Pseudomonas aeruginosa using the Most Probable Number method

La detección de Pseudomonas aeruginosa está  cobrando una importancia cada vez mayor, debido a que su presencia en el agua, tanto de uso industrial, hospitalario, público y doméstico, puede ocasionar brotes de importantes enfermedades para el hombre. Objetivo: Identificar P. aeruginosa en muestras de aguas tratadas y no tratadas, en forma simultánea con la identificación de coliformes totales y fecales. Métodos: Utilizando el caldo asparagina para la identificación presuntiva de P. aeruginosa y agar cetrimida, como prueba confirmativa, además de las pruebas de oxidasa y catalasa, en este trabajo se muestran resultados obtenidos en la identificación de P. aeruginosa en 69 muestras de agua de cisterna, pozo, presa y residual doméstico. Resultados: Del total de muestras analizadas, resultaron positivas a P. aeruginosa el 59.42%. Hubo presencia compartida de P. aeruginosa y coliformes totales y fecales en un 33.3%. Conclusiones: El empleo de la técnica del Número Más Probable para la identificación de Pseudomonas aeruginosa utilizando los medios de cultivo caldo asparagina y agar cetrimida, constituye un método eficaz para la detección de estemicroorganismo en muestras de aguas de diferentes fuentes.

The detection of Pseudomonas aeruginosa in water samples is crucial because the contamination of water sources such as industrial, hospital, public and domestic is frequently the cause of important human outbreaks. In this work we evaluated the used of the asparagine broth and cetrimide agar produced in BioCen, Havana, Cuba, for the presumptive and confirmative identification of P. aeruginosa, respectively. Objective: To identify P. aeruginosa in samples of treated and not treated waters, in simultaneous with the identification of total and fecal coliforms. Methods: Sixty nine samples from cistern water, well, prey and domestic waste were taken. The presumptive identification was performed by Most Probable Number Technique using asparagine broth, confirmative test was carried out using cetrimide agar followed by oxidase and catalasa tests. Results: The presence of P. aeruginosa was identified in the 59.42% of the samples analyzed. It was also demonstrated the common presence of Pseudomonas aeruginosa and total and fecal coliforms in 33.33% of the samples. Conclusions: The employment the Most probable Number technique for the identification of Pseudomonas aeruginosa using the culture media asparagine broth and cetrimide agar, it constitutes an effective method for the detection of this microorganism in samples of waters of different sources.

Alterations of plasma aspartic acid, glycine and asparagine levels in patients with major depressive disorder / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To evaluate the changes of plasma levels of the excitatory amino acid neurotransmitter aspartic acid (Asp), inhibitory neurotransmitter glycine (Gly) and asparagine (Asn) in patients with major depressive disorder (MDD).</p><p><b>METHODS</b>Plasma samples were collected from 15 MDD patients (9 males and 6 females, aged 32-64 y) and 14 healthy subjects (7 males and 7 females, aged 30-65 y); and also collected from 7 MDD patients (5 males and 2 females) 2 months after antidepressant treatment. The plasma levels of amino acids were determined by high performance liquid chromatography with fluorescence detection method.</p><p><b>RESULTS</b>Plasma Asp and Gly levels were significantly lower in MDD patients than those in controls (P<0.04). There were positive correlations between plasma levels of Gly and Asp, and between Gly and Asn (P<0.005) in the control group; while in MDD patients, a significant positive correlation was found only between plasma levels of Gly and of Asp (P<0.001). MDD patients did not show significant changes in plasma Asp, Asn and Gly levels after antidepressant treatment compared to those before treatment.</p><p><b>CONCLUSION</b>The reduced plasma Asp and Gly levels may serve as a clinical biomarker for MDD.</p>

Development of a novel vaccine against canine parvovirus infection with a clinical isolate of the type 2b strain

PURPOSE: In spite of an extensive vaccination program, parvoviral infections still pose a major threat to the health of dogs. MATERIALS AND METHODS: We isolated a novel canine parvovirus (CPV) strain from a dog with enteritis. Nucleotide and amino acid sequence analysis of the isolate showed that it is a novel type 2b CPV with asparagine at the 426th position and valine at the 555th position in VP2. To develop a vaccine against CPV infection, we passaged the isolate 4 times in A72 cells. RESULTS: The attenuated isolate conferred complete protection against lethal homologous CPV infection in dogs such that they did not develop any clinical symptoms, and their antibody titers against CPV were significantly high at 7-11 days post infection. CONCLUSION: These results suggest that the virus isolate obtained after passaging can be developed as a novel vaccine against paroviral infection.

Suplementos nutricionales orales a base de nuevos complejos de cobre, magnesio, manganeso y zinc

Suplementos nutricionales orales a base de nuevos complejos de cobre, magnesio, manganeso y zinc Los oligoelementos cobre, magnesio, manganeso y zinc intervienen en numerosos procesos metabólicos, enzimáticos, inmunológicos y tisulares, forman parte estructural de proteínas y pueden participar en la regulación de la expresión genética. La deficiencia de estos elementos esenciales dificulta el apropiado funcionamiento del organismo e induce el desarrollo de diversas enfermedades. Se debe garantizar la incorporación de oligoelementos a través de la dieta; sin embargo, la cantidad suministrada no siempre es suficiente y el uso de suplementos nutricionales convencionales presenta dos problemas; el primero se atribuye a la asociación de los metales a sales inorgánicas que generan una baja absorción e intolerancias a nivel gástrico y el segundo corresponde a las interacciones antagonistas entre diversos metales componentes de la formulación. Como una alternativa a los problemas mencionados, en este trabajo se propone la elaboración de tabletas para la administración oral de nuevos complejos de cobre, zinc, magnesio y manganeso ligados a los aminoácidos glicina y asparagina. En la síntesis de estos complejos, cada ligando se unió a duplas de cationes no antagonistas, se verificó la formación de los complejos por espectroscopía infrarroja, calorimetría de barrido diferencial, análisis termogravimétrico y difracción de rayos X de polvos, y se determinaron los tiempos de desintegración y de disolución in-vitro a las formas farmacéuticas finales.

Oral dietary supplements with copper, magnesium, manganese and zinc-based new complexes Oligoelements such as copper, magnesium, manganese and zinc are involved in several metabolic, enzymatic and immunological processes. They are also important for the integral tissue proteins and could be involved in gene expression regulation. The deficiency of these essential elements hampers the appropriate function of the body and may cause various diseases. Therefore, it is important to guarantee the incorporation of these trace elements in the diet, but the quantity provided is not always adequate for the optimum body performance. Currently, conventional nutritional supplements have two major problems. The first one is attributed to the association of inorganic salts with metals which might cause low absorption and gastric intolerance. The second problem is caused when several metals are present in a formulation which could lead to possible antagonistic interactions. For this reason, this study explores the development of cations (i.e., copper, zinc, magnesium and manganese) and amino acids (i.e., glycine and asparagine) new complexes formulated into compacts for oral administration. In each reaction, ligands were linked to non-antagonistic cation pairs. The complex formation was characterized by infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis and powder X-ray diffraction analyses. Compact disintegration and in-vitro dissolution tests for these complexes were also determined.

Optimal Extraction Conditions of Anti-obesity Lipase Inhibitor from Phellinus linteus and Nutritional Characteristics of the Extracts

In an effort to develop novel mushroom-derived anti-obesity nutraceuticals, water and ethanol extracts containing the lipaseinhibitory compound from Phellinus linteus were prepared, and their nutritional components were determined. The optimal conditions for the extraction of P. linteus lipase inhibitor involved the treatment of the fruiting bodies with distilled water at 80degrees C for 72 hr and 80% ethanol at 100degrees C for 60 hr, respectively. The distilled water extract and ethanol extract contained 10.9% and 6.11% of crude protein, and 0.96% and 15.86% of crude fat, respectively. Additionally, the distilled water extract contained a large quantity of minerals, including 239.5 mg of K, 39.3 mg of Mg, and 39.3 mg of Na. The free amino acid content of the distilled water extracts was also higher than that of the ethanol extracts, and in particular, the distilled water extracts contained 5,139 mg of asparagine, 3,891 mg of tryptophan, 2,598 mg of alanine, and 2,066 mg of serine in 100 g of the distilled water extracts. 100 g of the distilled water and ethanol extracts were found to contain 12.31 g and 8.16 g of malic acid, respectively.

Cross-reactivity of Vaccine and Fields Strains of Bovine Coronaviruses in Korea

Bovine coronavirus (BCoV) causes severe diarrhea in newborn calves, and is associated with winter dysentery in adult cattle and respiratory infections in calves and feedlot cattle. Although the Korean BCoV vaccine strain, BC94, was isolated in 1995, there has still been no report of a molecular characterization of the vaccine strain. To characterize the vaccine strain, relationships between BC94 and field strains were investigated, based on sequence analysis and cross-immunity. We determined the complete sequences of the HE, N, and S genes from BC94 and four NVRQS isolates (SUN5, A3, 0501, 0502). Due to its major role in antigenicity, the spike proteins of the BCoVs were analyzed. BC94 showed distinctive genetic divergence from field isolates collected from 2002 to 2005. BC94, SUN5, and A3 had no virulence-specific sequence and there was a single amino acid change, from asparagine to lysine at residue 175, in the polymorphic region. Strains 0501 and 0502 had virulence-specific sequences at all seven sites. Although the recently isolated Korean BCoVs and BC94 were genetically different, the cleavage site of spike genes at 763~768 (KRRSRR) and the antigenic domain II of the spike protein, amino acid position 528, were conserved in all NVRQS isolates. The antigenic relatedness of KCD9, representative of recent Korean BCoVs, was compared with the Korean vaccine strain BC94. KCD9 showed cross-reactivity against BC94 by virus neutralization (VN) test. These results suggest that BC94 is antigenically closely related to field isolates and is still effective as a vaccine strain.

Cross-reactivity of Vaccine and Fields Strains of Bovine Coronaviruses in Korea

Bovine coronavirus (BCoV) causes severe diarrhea in newborn calves, and is associated with winter dysentery in adult cattle and respiratory infections in calves and feedlot cattle. Although the Korean BCoV vaccine strain, BC94, was isolated in 1995, there has still been no report of a molecular characterization of the vaccine strain. To characterize the vaccine strain, relationships between BC94 and field strains were investigated, based on sequence analysis and cross-immunity. We determined the complete sequences of the HE, N, and S genes from BC94 and four NVRQS isolates (SUN5, A3, 0501, 0502). Due to its major role in antigenicity, the spike proteins of the BCoVs were analyzed. BC94 showed distinctive genetic divergence from field isolates collected from 2002 to 2005. BC94, SUN5, and A3 had no virulence-specific sequence and there was a single amino acid change, from asparagine to lysine at residue 175, in the polymorphic region. Strains 0501 and 0502 had virulence-specific sequences at all seven sites. Although the recently isolated Korean BCoVs and BC94 were genetically different, the cleavage site of spike genes at 763~768 (KRRSRR) and the antigenic domain II of the spike protein, amino acid position 528, were conserved in all NVRQS isolates. The antigenic relatedness of KCD9, representative of recent Korean BCoVs, was compared with the Korean vaccine strain BC94. KCD9 showed cross-reactivity against BC94 by virus neutralization (VN) test. These results suggest that BC94 is antigenically closely related to field isolates and is still effective as a vaccine strain.

Relationship between the antileukemic activity of L-asparaginase and Asn level around leukemic cells / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the antileukemic activity of L-asparaginase through determining the changes of 4 kinds of amino acids (Asn, Aspa, Glu and Gln) in cell culture medium.</p><p><b>METHODS</b>Following L-Asp treatment with designed concentrations and duration, the IC50 (inhibitory concentration 50%) of 8 kinds of common leukemia cell lines (U937, HL-60, Jurkat, NB4, THP-1, Namalwa, Karpass299, K562) were determined by CCK-8 assay. The changes of the 4 kinds of amino acids mentioned above were detected by high performance liquid chromatography (HPLC).</p><p><b>RESULTS</b>The asparagines in cell culture medium were rapidly exhausted when treated with 0.01 U/mL L-Asp for 4 hrs or 1 U/mL L-Asp for 5 minutes. There were significant differences in the sensitivities to L-Asp of different leukemia cell lines. The sensitivities to L-Asp of various cell lines were dose-dependent. Low concentration of L-Asp resulted in a low IC50 and the IC50 increased following the L-Asp concentration increased.</p><p><b>CONCLUSIONS</b>Different leukemia cell lines have different sensitivities to L-Asp, suggesting that exhaustion of asparagines around leukemia cells could not reflect the treatment efficacy of L-Asp. L-Asp antileukemic activity is dose-dependent, which suggests the importance of high-dose L-Asp on childhood acute lymphoblastic leukemia.</p>

Purification and characterization of vigna unguiculata cultiver asparaginase

Asparaginase [EC 3.5.1.1] activity was determined in non germinating seeds and germinating seeds of five Egyptian cowpea [Vigna unguiculatd] cultivars [Kareem 7, Dokki 331, Kafer El-Sheikh 1, Kaha 1 and Fodder]. The specific activities of germinating seeds asparaginase in different cultivars were higher than the specific activities of non germinated seeds of these cultivars. Asparaginase was purified from Fodder cultivar germinating seeds [the highest specific activity] and resolved into three peaks with asparaginase activities by DEAE sepharose, designated by asp I, asp II and asp III. The molecular weight of asp II was 70 kDa for native enzyme using gel filtration. By using SDS-PAGE electrophoresis, asp II had molecular weight about 35 kDa suggesting that a dimeric structure for asp II. AspII had a Km value 1.25 mM for asparagine and a pH optimum at 8.0. Asp II had a temperature optimum and heat stability at 40 °C. The fodder cultivar asp II activity was specific for L-asparagine and did not hydrolyze D-asparagine. It is not specific for L-glutamine. Ni[2+] and Co[2+] had activator effects on asp II but other metals ions had inhibitory effect

[Effect of potato cultivar on acrylamide formation in potato chips]

In April 2002, a research group at Stockholm University and the Swedish Food Administration announced that significant amounts of acrylamide might be formed during common heat processing of foods. Since acrylamide is classified as "probably carcinogenic to humans" by the International Agency for Research on Cancer [IARC], these findings were considered as alarming. The most important food sources of dietary acrylamide are fried potato products like chips and French fries, which are popular snacks in Iran. The aim of this study was to investigate the effects of reducing sugars and amino acids in three 'potato cultivars on acrylamide formation in potato chips produced on a laboratory scale. Potato chips samples were produced on lab-scale from three potato cultivars namely Sante, Agria and Omidbakhsh by frying at 180°C for 4.15 min. Reducing sugars [glucose and fructose] and asparagine concentration in raw potato samples were determined using HPLC. A suitable and valid method was set up for determination of acrylamide in the chips samples by gas chromatography/mass spectrometry, GC/MS. The reducing sugars and acrylamide contents were significantly different among potato chips samples produced from different cultivars [p<0.05]. The highest amount of reducing sugars was found in cultivar Sante [3513 mg/kg] followed by Agria [2111 mg/kg] and Omidbakhsh [1622 mg/kg], respectively. On the other hand, cultivar Omidbakhsh had the highest amount of asparagine [1871 mg/kg]. The highest amount of acrylamide [8825 mg/kg] was formed in the chips from cultivar Sante and the lowest amount was formed in the chips from cultivar Omidbakhsh [5112 micro g/kg]. A high content of asparagine in raw potatos was not necessarily an indication of high content of acrylamide in the produced chips. The two cultivars with higher content of reducing sugars, showed the higher potential for acry1amide formation in the chips. This indicates that the concentration of reducing sugars is a more important parameter than asparagine content in the formation of acrylamide in potato chips. The selection of proper potato cultivars with naturally lower contents of precursors of acrylamide specially reducing sugars is important factor to reduce the acrylamide formation during production of potato chips. With respect to the results obtained from this study, it is suggested that cultivar Omidbakhsh is the most suitable cultivar in Iran for the industrial production of potato chips with low levels of acrylamide

Caracterização bioquímica e molecular de possíveis alvos terapêuticos do metabolismo de aminoácidos em Tripanossomatídeos / Biochemical and molecular characterization of possible tarepeutic targets against Trypanosomatids in the amino acid metabolism

Trypanosoma cruzi e Leishmania spp. são parasitas de grande relevância médica nas Américas e em países da Europa e Ásia. Esses organismos apresentam um ciclo de vida heteroxeno infectando hospedeiros vertebrados e invertebrados e, portanto, precisam se adaptar às diferentes condições ambientais. Dessa forma, diversas enzimas metabólicas, proteínas e transportadores participam no ajuste do metabolismo às condições ambientais e flutuações na disponibilidade de nutrientes do meio. Nesse aspecto, os aminoácidos são de importância vital para o metabolismo de tripanossomatídeos, porém pouco se sabe da dinâmica do transporte desses nutrientes para dentro da célula e existem algumas lacunas no estudo de algumas enzimas envolvidas no metabolismo de aminoácidos. Portanto, uma dos objetivos desse trabalho foi caracterizar bioquimicamente o transporte de L- glutamato, um aminoácido importante para o ciclo de vida desses organismos e as formas presentes no inseto de diversos tripanossomatídeos utilizam L-glutamato no metabolismo energético. A incorporação de glutamato ao longo do tempo foi estudada em formas promastigotas de Leishmania amazonensis, foi possível observar que a incorporação é saturável e apresenta uma faixa de linearidade durante os primeiros 120 segundos de incubação com aminoácido radioativamente marcado, atingindo um platô após 15 minutos...Os tripanossomatídeos são capazes de metabolizar L-glutamato para produção de energia, o fato de L. amazonensis incorporar L-glutamato com eficiência é um indicativo da relevância desse aminoácido no metabolismo desses parasitas. O outro objetivo do trabalho, se relaciona com a busca de alvos terapeêuticos em potencial no metabolismo de aminoácidos em Trypanosoma cruzi. A asparagina é de importância vital para a síntese correta de protéinas e para processos de modificações pós-traducionais como N-glicosilação...Além disso, também identificamos uma sequência codificante correspondente a enzima L-Asparaginase (L-Asp)...

Effect of glycosylation at Asn302 of pro-urokinase on its stability in culture supernatant / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the effect of glycosylation at Asn302 of pro-urokinase (pro-UK) on the stability in culture supernatant.</p><p><b>METHODS</b>Nonglycosylated pro-UK was constructed by site-directed mutagenesis of Asn302 to Ala302. The pro-UK mutant and native pro-UK were transfected into dhfr(-)-CHO cells, and serum-free culture supernatant was harvested and incubated at 4 degrees C and 37 degrees C, respectively. The pro-UK activity in culture supernatant was measured by the optical density (OD) increase with time (12 hours) at 405 nm. Without thermolysin activation, the percentage of single chain pro-UK was measured.</p><p><b>RESULTS</b>After 48 hours of incubation at 4 degrees C, the activities of pro-UK mutant and native pro-UK decreased 3.7% and 2.9% respectively, and at 37 degrees C decreased 37.9% and 23.5%, respectively. The total activity of native pro-UK was significantly higher than that of nonglycosylated mutant at 37 degrees C. The single-chain percentage of native pro-UK was higher than that of nonglycosylated mutant at both 4 degrees C and 37 degrees C.</p><p><b>CONCLUSION</b>Higher temperature increases the proteolysis of pro-UK. The glycosylation site on Asn302 is beneficial to pro-UK stability in culture supernatant.</p>