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Introducción: La diarrea aguda es una entidad frecuente en pediatría, constituyendo una de las principales causas de mortalidad en países en desarrollo y en niños menores de cinco años. Si bien la alimentación representa uno de los pilares fundamentales en el tratamiento de la misma, no existe consenso entre los profesionales en cuanto a la indicación de leche deslactosada durante el curso del cuadro. Objetivos: Realizar una revisión sistemática para estudiar el impacto del consumo de leche deslactosada vs leche regular en la duración de la diarrea aguda infecciosa en niños. Materiales y métodos: Se realizó una revisión sistemática incluyendo artículos publicados desde el año 2008 al 2023, utilizando para la búsqueda las bases de datos PubMed, Lillacs, Cochrane Library y literatura gris. Se incluyeron estudios experimentales, observacionales, revisiones, guías de atención y metaanálisis, realizados en pacientes pediátricos sin patologías de base, cursando cuadro de diarrea aguda infecciosa, que compararan el uso de leche deslactosada frente a leche regular. Resultados: Se seleccionaron doce artículos. En 9 de ellos se constató una disminución en la duración de la diarrea en los pacientes que recibieron leche deslactosada con una diferencia de medias de 18 horas (en un rango entre 4 y 32.6 horas). No se reportaron diferencias estadísticamente significativas en la mortalidad entre el uso de una u otra fórmula láctea. En relación al uso de una u otra fórmula no se objetivaron variaciones en el peso estadísticamente significativas. La necesidad de hospitalización fue similar entre ambos grupos. Solo un artículo analizó la frecuencia o volumen de deposiciones sin encontrar diferencias significativas (AU)
Introduction:Acute diarrhea is frequent in pediatrics, and constitutes one of the main causes of mortality in developing countries and in children under five years of age. Although feeding is one of the fundamental pillars in the treatment of diarrhea, there is no consensus among professionals regarding the indication of lactose-free milk during the course of the symptoms. Objectives: To conduct a systematic review to study the impact of lactose-free milk vs. regular milk consumption on the duration of acute infectious diarrhea in children. Materials and methods: A systematic review was conducted including articles published between 2008 and 2023, using PubMed, Lillacs, Cochrane Library databases, and gray literature for the search. Experimental and observational studies, reviews, care guidelines and meta-analysis were included, conducted in pediatric patients without underlying diseases, with acute infectious diarrhea, comparing the use of lactose-free milk versus regular milk. Results: Twelve articles were selected. Nine of them showed a decrease in the duration of diarrhea in patients who received lactose-free milk with a mean difference of 18 hours (ranging from 4 to 32.6 hours). No statistically significant differences in mortality were reported between the use of one or the other milk formula. Regarding the use of one or the other formula, there were no statistically significant variations in weight. The need for hospital admission was similar between the two groups. Only one article analyzed stool frequency or volume with no significant differences (AU)
Sujet(s)
Humains , Nouveau-né , Nourrisson , Enfant d'âge préscolaire , Maladie aigüe , Résultat thérapeutique , Lait/composition chimique , Diarrhée du nourrisson/thérapie , Lactose/administration et posologie , Lactose/effets indésirablesRÉSUMÉ
Lactose intolerance refers to the poor absorption of lactose caused by insufficient number or low activity of lactase,which leads to one or more gastrointestinal symptoms.Newborns are mainly develop-mental and secondary lactase deficiency,with various clinical symptoms,which are easy to be missed and mis-diagnosed.Neonatal lactose intolerance is often diagnosed by fecal reducing sugar and pH determination and urinary galactose determination,but there are still many hospitals that have not carried out related inspection projects.Although there is currently a lack of specific guidelines for neonatal lactose intolerance,but in the context of promoting breastfeeding,reducing the abuse of special milk powder,and rational use of efficient,high-quality lactase is particularly important.In addition,a series of problems involved in the diagnosis and treatment of neonatal lactose intolerance in China need to be further explored.How to find a balance point in the treatment of lactose intolerance will be a direction for future research.
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ABSTRACT Background: Lactose tolerant test (LTT) is the most broadly used diagnostic test for lactose intolerance in Brazil, is an indirect, minimally invasive and a low-cost test that is widely available in primary care and useful in clinical practice. The C/T-13910 polymorphism in lactase persistence has been well characterized in Caucasian populations, but there are no studies evaluating the concordance between C/T-13910 polymorphism genotyping results and LTT results in Brazil, where the population is highly mixed. Objective: We aimed to evaluate agreement between presence of C/T-13910 polymorphism genotyping and malabsorption in LTT results. Methods: This is a retrospective analysis of a Brazilian population whose data were collected from a single laboratory database present in several Brazilian states. Results of individuals who underwent both genetic testing for lactose intolerance (C/T-13910 polymorphism genotyping) and an LTT from April 2016 until February 2019 were analysed to evaluate agreement between tests. Groups were classified according to age (<10-year-old (yo), 10-17 yo, ≥18 yo groups) and state of residence (São Paulo or Rio Grande do Sul). Results: Among the 404 patients evaluated, there was agreement between the genotyping and LTT results in 325 (80.4%) patients and discordance in 79 (19.6%) patients (k=0.42 -moderate agreement). Regarding the genotype, 47 patients with genotype C/C (lactase nonpersistence) had normal LTT results, and 32 with genotype C/T or T/T (indicating lactase persistence) had abnormal LTT results. Neither age nor state of residence (Rio Grande do Sul or São Paulo) affected the agreement between test results. Conclusion: Considering the moderate agreement between C/T-13910 polymorphism genotyping and LTT results (κ=0.42) in the Brazilian population, we hypothesize that an analysis of other polymorphisms could be a strategy to improve the agreement between genotyping and established tests and suggest that additional studies should focus on exploring this approach.
RESUMO Contexto: O teste de tolerancia à lactose (TTL) é ampliamente utilizado por ser minimamente invasivo e de baixo custo, disponível na atenção primária e muito útil na prática clínica. Está bem estabelecido o polimorfismo C/T-13910 na persistência da lactase em populações caucasianas, mas não há estudos avaliando a concordância entre os resultados da genotipagem do polimorfismo C/T-13910 e do TTL no Brasil, onde a população é altamente miscigenada. Objetivo: Avaliar a concordância entre a presença do polimorfismo C/T-13910 e a má absorção nos resultados do TTL. Métodos: Análise retrospectiva de dados coletados de um laboratorio presente em vários estados brasileiros. Os resultados dos pacientes que realizaram um teste genético para intolerância à lactose (genotipagem do polimorfismo C/T-13910) e um TTL de abril de 2016 a fevereiro de 2019 foram analisados para avaliar a concordância entre os testes. Os grupos foram classificados de acordo com a idade (<10 anos; 10-17 anos, ≥18 anos) e estado de residência (São Paulo ou Rio Grande do Sul). Resultados: Entre os 404 pacientes avaliados, houve concordância entre os resultados de genotipagem e TTL em 325 (80,4%) pacientes e discordância em 79 (19,6%) pacientes (K=0,42 - concordância moderada). Em relação ao genótipo, 47 pacientes com genótipo C/C (não persistência de lactase) apresentaram TTL normal e 32 com genótipo C/T ou T/T (indicando persistência da lactase) apresentaram TTL anormal. A idade e o estado de residência (Rio Grande do Sul ou São Paulo) não afetaram a concordância entre os resultados dos exames. Conclusão: Considerando a concordância moderada entre a genotipagem do polimorfismo C/T-13910 e os resultados de TTL (κ=0,42) na população brasileira, sugerimos que a análise de outros polimorfismos poderia ser uma estratégia para melhorar a concordância entre os testes.
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Abstract Background: Goat milk production has been increasing in northern Mexico; however, there is little information available about its quality. Objective: To compare goat milk quality during three seasons among creole goats in a traditional grazing system and stabled Saanen and French-Alpine goats. Methods: An experiment was performed in a completely randomized nested design with seasonality factor (fixed effects) with three levels (rain, transition, and drought) and breed factor (fixed effect with three levels (Creole, Saanen and French-Alpine)) nested within the season-of-the-year factor. Fifteen goats were randomly selected: five Creole in the extensive grazing system, five stabled Saanen, and five stabled French-Alpine. The factors assessed in milk were fat content, non-fat solids, protein, lactose, salts, density, freezing point, conductivity, and pH (using a Lactoscan® device). Results: With respect to season for all the breeds: fat, non-fat solids, protein, lactose, and salt contents were higher (p≤0.05) for goats sampled in the rainy season, followed by drought and transition seasons, respectively. The variables related to milk quality by breed and season showed that milk fat content of creole goats was greater (p≤0.05) in the drought season; salt and non-fat content (p≤0.05) in the three seasons of the year; density and protein increased (p≤0.05) in the transition and rainy seasons, while lactose was greater (p≤0.05) in drought and rainy seasons; protein was greater (p≤0.05) in transition and rainy seasons; and the freezing point was lower (p≤0.05) in the transition season. Regarding conductivity, French-Alpine milk was greater (p≤0.05) in the drought season. Conclusion: Season of the year significantly affects milk quality, with increased quality during the rainy season in creole grazing goats.
Resumen Antecedentes: La producción de leche de cabra se ha venido incrementando en el norte de México,; sin embargo, existe poca información sobre su calidad. Objetivo: Comparar la calidad de la leche de cabra durante tres épocas del año para cabras criollas en pastoreo y cabras puras de dos razas diferentes bajo estabulación. Métodos: El experimento se realizó mediante un diseño anidado completamente aleatorizado, con el factor época del año (efecto fijo) con tres niveles (lluvia, transición y sequia) y el factor raza (efecto fijo) con tres niveles (Criolla, Saanen y Alpino-Francesa) anidado dentro del factor época del año. En el sistema de pastoreo extensivo se eligieron al azar cinco cabras de raza Criolla, en el sistema estabulado se eligieron al azar cinco cabras de la raza Saanen y cinco de la raza Alpino-Francesa. La variables medidas fueron: contenido de grasa, sólidos no grasos, proteína, lactosa, sales, densidad, punto de congelación, conductividad y pH (utilizando el dispositivo Lactoscan®). Resultados: Respecto a la temporada del año para las tres razas se encontró que los contenidos en leche de grasa, sólidos no grasos, proteína, lactosa y sales fueron mayores (p≤0,05) en la época de lluvias, seguido por la leche muestreada en sequía y transición. Las variables por raza y temporada del año arrojaron que la grasa fue mayor (p≤0,05) en cabras criollas en sequía, solidos no grasos fue mayor (p≤0,05) en las tres temporadas del año en cabras criollas, la densidad aumentó (p≤0,05) en cabras criollas en transición y lluvia. La proteína fue mayor (p≤0,05) en cabras criollas en transición y lluvia, mientras que la lactosa fue mayor (p≤0,05) en cabras criollas en sequía y lluvia. El menor punto de congelación (p≤0,05) se presentó en cabras criollas en transición, la conductividad fue mayor (p≤0,05) en cabras Alpina-Francesa en sequía y la concentración de sales fue mayor (p ≤0,05) en cabras criollas durante las tres temporadas. Conclusión: Existe un marcado efecto de la temporada sobre la calidad de la leche, siendo la epoca de lluvias cuando se presenta mejor calidad en cabras criollas en pastoreo.
Resumo Antecedentes: No norte do México a produção de leite de cabra aumentou; no entanto, a qualidade do leite é desconhecida. Objetivo: Comparar a qualidade do leite de cabra durante três estações do ano com cabras crioulas em sistema de pastoreio tradicional e cabras Saanen e franco-alpinas em estábulos. Métodos: O experimento foi realizado através de um delineamento completamente casualizado com o fator de sazonalidade (efeitos fixos) com três níveis (chuva, transição e seca) e fator de raça (efeito fixo com três níveis (crioulo, Saanen e franco-alpino) aninhados dentro do fator estação do ano quinze cabras foram selecionadas aleatoriamente, cinco no sistema de pastejo extensivo, cinco Saanen e cinco Franco-Alpino no sistema estábulo. Os fatores avaliados no leite foram teor de gordura, sólidos desengordurados, proteína, lactose, sais, densidade, ponto de congelamento, condutividade e pH pelo aparelho Lactoscan®. Resultados: Em relação às estações do ano, nas três raças, mostrou que os teores de gordura, sólidos desengordurados, proteínas, lactose e sal foram maiores (p≤0,05) nas cabras cujo leite foi amostrado na ocasião um de chuvas seguido por aquele amostrado nas estações de seca e transição, respectivamente. As variáveis relacionadas à qualidade do leite de cabra por raça e ano, mostraram que nas cabras crioulas o teor de gordura foi maior (p≤0,05) na estação seca; teor de sal e gordura (p≤0,05) nas três estações do ano; a densidade aumentou significativamente e o teor de proteína foi maior (p≤0,05) nas estações de transição e chuvas, enquanto o valor de lactose foi maior (p≤0,05) nas estações seca e chuvosa; o teor de proteína foi maior (p≤0,05) nas estações de transição e chuvas; e o ponto de congelamento foi menor (p≤0,05) na estação de transição. Em relação à condutividade, o leite de cabra franco-alpino apresentou valor significativamente superior (p≤0,05) na seca. Conclusão: A qualidade do leite tem um efeito significativo por estação, sendo que a estação chuvosa aumentou a qualidade do leite em cabras crioulas em pastejo.
RÉSUMÉ
OBJECTIVE To prepare the nanoporous flower-shaped lactose (FL)-loaded curcumin (Cur) solid lipid nanoparticles (SLN) inhalation powder (Cur-SLN-FL), and to investigate its inhibition effect on LPS-induced apoptosis of BEAS- 2B cells. METHODS Using different kinds (lactose, sucrose, mannitol, trehalose) and different amounts (2%, 3%, 5%) of freeze-dried protectants as objects, the suspension of Cur-SLN was micronized by freeze-drying technology into lyophilized powder, which was then mixed with FL and sieved by a 200-mesh sieve to obtain Cur-SLN-FL. The physicochemical properties of Cur-SLN-FL was characterized by scanning electron microscopy and laser particle size analyzer. Using BEAS-2B cells cultured in vitro as objects, LPS-induced apoptosis and the changes of mitochondrial membrane potential after treatment of Cur-SLN-FL were detected by Annexin Ⅴ/PI double staining method and JC-1 kit. RESULTS With 3% trehalose as Cur-SLN freeze-dried protective agent, the freeze-dried powder obtained was compact and full in shape, did not shrink and collapse, and was uniform in color and light-yellow powder, which could be completely dissolved in 30 s. When FL and Cur-SLN freeze-dried powder were mixed at a ratio of 1∶2, it had a higher deposition rate of secondary distribution ([ 40.92±0.02)%]. SEM results showed that Cur-SLN-FL had a flower-shaped appearance with an average particle size of (4.95±0.57) μm and an aerodynamic particle size of (4.03±0.40) μm. The critical relative humidity of Cur-SLN-FL was about 54%, and the evacuation rate was (90.34 ± 1.21)%; the quantity of fine particles that could be inhaled by Cur-SLN-FL in the 2-7 receiving discs was (47.5±0.7)%, and the measured aerodynamic particle size was (4.33±0.08) μm. The LD50 of Cur-SLN-FL to BEAS-2B cells was 5.809 mg/mL. The apoptosis rate of model cells was significantly reduced after treatment of Cur-SLN-FL, and the mitochondrial membrane potential was significantly increased (P<0.05). CONCLUSIONS The preparation process of Cur-SLN-FL is simple and feasible. Cur-SLN-FL can improve LPS-induced apoptosis of BEAS-2B cells, and this effect is related to the regulation of mitochondrial membrane potential.
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ObjectiveTo explore the effects of Wumeisan on gut lactase activity and microflora diversity of mice with dysbacteriosis diarrhea. MethodThe mice were randomly divided into 4 groups, namely, the normal group, the model group, and the low-dose and high-dose Wumeisan groups, with 8 mice in each group. The mouse model was made by gavage of mixed antibiotics for 7 d, and the low-dose and high-dose Wumeisan groups (5.98, 11.96 g·kg-1) were given gavage for 7 d continuously. The normal group and the model group were given the same volume of sterile water. The changes in the body weight, food intake, and diarrhea of mice were recorded. Feces were collected after the last administration, and the lactase activity was detected by the colorimetric method. The gut microbiota changes were detected by the 16S rRNA high-throughput sequencing technology. ResultCompared with those in the normal group, the mice in the model group had dilute and soft stools, reduced body mass, reduced food intake, reduced lactase activity, significantly reduced intestinal flora diversity, and significant changes in the relative abundance phylum and genus levels of flora. Compared with the model group, Wumeisan reduced the diarrhea rate of mice, promoted the rapid recovery of body weight and food intake, increased the lactase activity decreased by antibiotic, improved the community abundance and diversity of mice with dysbacteriosis, and made the species composition closer to that in the normal group. The abundance of three phyla (Bacteroidota, Proteobacteria, Verrucomicrobiota) and nine genera (Odoribacter, Enterococcus, Clostridium innocuum group, etc.) of mice with diarrhea were regulated by Wumeisan. Among them, norank f Muribaculaceae, norank f norank o Clostridia UCG-014, Lachnospiraceae NK4A136 group, and Odoribacter showed significant positive correlation with the body weight and lactase activity, and Escherichia-Shigella, Enterobacter, Enterococcus, and Clostridium innocuum group showed significant positive correlation with the diarrhea rate. Function prediction showed that the high-dose Wumeisan significantly reseted 6 functional levels of metabolism, genetic information processing, and human diseases, and had positive effects on endocrine and metabolic diseases, immune diseases, infectious disease, and parasitic infectious diseases. ConclusionWumeisan can relieve the symptoms of dysbacteriological diarrhea by increasing the lactase activity and regulating the gut microbiota composition.
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OBJECTIVE To investigate the effects and mechanism of curcumin (Cur) solid lipid nanoparticles (SLN) loaded with flower-shaped lactose (Cur-SLN-FL) for lung inhalation on lung inflammation in chronic obstructive pulmonary disease (COPD) model mice. METHODS Firstly, the irritation of Cur-SLN-FL to lung tissue was investigated, and the local safety of inhalation materials was determined. Then, 10 mice were randomly selected and injected with normal saline through the trachea, and the other 50 mice were all injected with porcine trypsin solution (concentration of 33.3 mg/mL, dosage of 1.0 mL/kg) to induce the COPD model. After normal feeding for 28 days, the mice were divided into sham operation group, model group, budesonide group (20 mg/kg), Cur-SLN-FL high-dose and low-dose groups (100, 50 mg/kg), with 10 mice in each group. The corresponding drugs were given to each group, once a day, for 14 consecutive days. Twenty-four hours after the last administration, the bronchoalveolar lavage fluid (BALF) of mice in each group was collected and the differential count of white blood cells was determined. Hematoxylin-eosin (HE) staining was used to observe the histopathology of the trachea and lung tissue in each group. Masson staining was used to detect collagen deposition in the lung tissue of mice in each group. Immunohistochemical method was used to detect the positive expressions of nucleotide-binding oligomerization domains-like receptor protein-3 (NLRP3), caspase-1 and interleukin-1β (IL-1β) in lung tissue of mice. Western blot assay was used to detect the protein expressions of NLRP3, caspase-1 and nuclear factor of kappa B(NF-κB) in lung tissue. RESULTS Cur-SLN-FL had no obvious pulmonary irritation. Compared with the sham operation group, the total number of white blood cells, neutrophils and eosinophils in BALF of the model group increased significantly, while the number of lymphocytes decreased significantly (P<0.05); ciliated columnar epithelium proliferated, thickened and exfoliated in the trachea, mucus accumulated in the cavity and interstitial inflammatory cells infiltrated in the lung tissue;the deposition of collagen fibers in lung tissue increased significantly, the positive expressions of NLRP3, caspase-1 and IL-1β in lung tissue increased significantly, and the expressions of NLRP3, caspase-1 and NF-κB protein in lung tissue all increased significantly (P<0.05). After giving Cur-SLN-FL, the above indexes were all improved to certain extent. CONCLUSIONS Cur-SLN-FL can improve the pulmonary inflammatory reaction in COPD model mice,and its mechanism may be through regulating the NLRP3 signaling pathway, inhibiting the expressions of caspase-1, NF-κB and IL-1β, thus alleviating the process of pulmonary fibrosis in COPD model mice.
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Introducción: Los GOS son prebióticos naturales presentes en la leche materna que pue-den obtenerse enzimáticamente a partir de la lactosa de leche de vaca durante la fabricación de yogur. El producto lácteo resultante será reducido en lactosa y contendrá prebióticos y bacterias potencialmente probióticas. Sin embargo, mantendrá la baja relación Ca/Pi que aporta la leche de vaca, lo que podría alterar el remodelamiento óseo y la mineralización. Objetivo: comparar si un yogur reducido en lactosa que contiene GOS (YE) ofrece ventajas adicionales respecto de un yogur regular sin GOS (YR) sobre las absorciones (Abs) de Ca y Pi, retención y calidad ósea durante el crecimiento normal. Al destete, ratas machos fueron divididas en 3 grupos alimentados con AIN Ì93-G (C), YE o YR durante 28 días. Resultados: YE mostró el mayor aumento de lactobacilos fecales; producción de ácidos grasos de cadena corta especialmente p, profundidad de las criptas colónicas y menor pH cecal. El %AbsCa y %AbsPi aumentó en el siguiente órden: YE> YR> C (p < 0,05). El contenido de Ca y Pi en fémur, la densidad y contenido mineral óseos y los parámetros biomecánicos fueron similares en YE y C, mientras que YR mostró valores significativa-mente menores (p < 0,05). Conclusiones: YE aumentó las Abs y biodisponibilidad de minerales, alcanzando la retención y calidad ósea de C. El aumento en las Abs observado en YR no logró obtener la retención y calidad ósea de C. Conclusión: YE habría contrarrestado el efecto negativo del mayor aporte de Pi de la leche de vaca y sería una buena estrategia para lograr el pico de masa ósea y calidad del hueso adecuados, especialmente en individuos intolerantes a la lactosa. (AU)
Breast milk contains an optimal calcium/phosphate (Ca/Pi) ratio and GOS. These natural prebiotics can be enzymatically produced via cow's milk lactose inyogurt manufacture. This milk product is low in lactose and contains prebiotics and potentially probiotic bacteria but maintains a low Ca/Pi ratio that could alter bone remodeling and mineralization. We evaluated if a lactose-reduced yogurt containing GOS (YE) offers additional advantages over regular yogurt without GOS (YR) on Ca and Pi absorption (Abs), bone retention and quality during normal growth. Weaning male rats were divided into 3 groups fed AIN'93-G (C), YE or YR for 28 days. Results: YE showed the highest increase in fecal lactobacilli; short-chain fatty acids production, especially propionate and butyrate; intestine crypt depth, and the lowest cecal pH. AbsCa% and AbsPi% increased in this order: YE> YR> C (p <0.05). Ca and Pi content in femur, bone density and mineral content, and biomechanical parameters were similar in YE and C, while YR showed the significantly lowest value (p < 0.05). Conclusions: YE increased mineral Abs reaching the retention and bone quality of C. Although YR increased Abs, bone retention and quality did not achieve C values. Seemingly, YE compensated for the negative effect of the higher Pi supply and would be a good strategy to achieve adequate peak bone mass and bone quality, especially in lactose intolerant individuals. (AU)
Sujet(s)
Animaux , Rats , Oligosaccharides/métabolisme , Ostéogenèse/physiologie , Calcium alimentaire/pharmacocinétique , Phosphore alimentaire/pharmacocinétique , Absorption intestinale/physiologie , Lactose/métabolisme , Magnésium/pharmacocinétique , Tibia/anatomie et histologie , Yaourt/analyse , Calcium alimentaire/métabolisme , Absorptiométrie photonique , Densité osseuse , Interprétation statistique de données , Phosphore alimentaire/métabolisme , beta-Galactosidase/synthèse chimique , Rat Wistar , Lactobacillus delbrueckii/isolement et purification , Fémur/anatomie et histologie , Gros intestin/anatomie et histologie , Magnésium/métabolisme , Valeur nutritiveRÉSUMÉ
Introducción: los bebés deben beneficiarse de la leche materna, incluso cuando presentan intolerancia a la lactosa. Por esto, se debe recurrir a la obtención de leche materna deslactosada. Objetivo: analizar el efecto de la enzima beta galactosidasa en la hidrólisis de la lactosa de leche materna madura para bebés clínicamente diagnosticados con intolerancia a la lactosa. Materiales y método: estudio exploratorio, descriptivo y explicativo. El contenido de lactosa se cuantificó desde el inicio hasta el final del tratamiento, controlando temperatura, tiempos y cantidad de enzima ß-galactosidasa adicionada en la leche materna. Se recolectaron 1000 ml de leche materna, obtenidos del Banco de Leche del Hospital General de Medellín (Antioquia, Colombia). Resultados: las muestras donadas se encontraban pasteurizadas y posteriormente fueron sometidas a la acción de la enzima lactasa. Se cuantificó el contenido de lactosa sin la enzima, reportando en promedio 6,34 mg/100 ml ± 0,23. El mayor aporte de lactosa obtenido posterior a la exposición a la enzima (30 minutos) fue de 6,07 mg/ml ± 0,35 (correspondiente a 95 % del contenido inicial), finalizando con un aporte de 0,35 % a una concentración de 0,4 % tras 24 horas, porcentaje que representa 95 % de la hidrólisis total en la leche materna. Conclusiones: en todas las muestras analizadas de diferentes madres se pudo obtener leche materna con bajas concentraciones de lactosa tras 24 horas de haber sido sometidas a la acción de ß-galactosidasa. Lo anterior se establece como una alternativa para los bebés intolerantes a la lactosa, que permitiría no privarlos de todos los beneficios que ofrece este alimento.
Introduction: Babies should benefit from breast milk, even when they are lactose intolerant. For this reason, parents should resort to obtaining lactose-free breast milk. Objective: To examine the effect of the enzyme ß-galactosidase on the hydrolysis of lactose in mature breast milk for babies clinically diagnosed with lactose intolerance. Materials and method: Exploratory, descriptive, and explanatory study. The lactose content was quantified from the beginning to the end of the treatment, controlling variables such as temperature, times, and the amount of ß-galactosidase enzyme added in breast milk. A total of 1000 ml of breast milk were obtained from the milk bank at Hospital General de Medellín (Antioquia, Colombia). Results: Donated samples were first pasteurized and subsequently subjected to the action of the enzyme lactase. The lactose content without the enzyme was quantified, reporting an average of 6.34 mg/100 mL±0.23. The highest contribution of lactose obtained after exposure to the enzyme was 6.07 mg/mL±0.35 (corresponding to 95% of the initial content), at 30 minutes, ending with a contribution of 0.35% at a concentration of 0.4% in 24 hours, percentage that represents 95% of total hydrolysis in breast milk. Conclusions: In all the examined samples from different mothers, it was possible to obtain breast milk with low concentrations of lactose 24 hours after these were exposed to the action of ß-galactosidase. This becomes an alternative for feeding lactose intolerant babies and not deprive them from all the benefits offered by breast milk.
Introdução: os bebês se devem beneficiar do leite materno, mesmo quando tenham intolerância à lactose, razão pela qual se deve recorrer à obtenção de leite materno sem lactose. Objetivo: analisar o efeito da enzima beta-galactosidase na hidrólise da lactose no leite materno maduro para bebês diagnosticados clinicamente com intolerância à lactose. Materiais e método: estudo exploratório, descritivo, explicativo. O teor de lactose foi quantificado do início ao fim do tratamento; temperatura, tempos e quantidade de enzima beta-galactosidase adicionada no leite materno foram controlados; foram coletados 1000ml de leite materno, obtidos no Banco de Leite do Hospital General de Medellín (Antioquia, Colômbia). VResultados: as amostras doadas foram pasteurizadas e posteriormente submetidas à ação da enzima lactase. O teor de lactose sem a enzima foi quantificado, relatando uma média de 6,34mg/100ml±0,23. A maior contribuição de lactose obtida após a exposição à enzima foi de 6,07mg/ml±0,35 (correspondendo a 95% do conteúdo inicial) em 30 minutos, finalizando com uma contribuição de 0,35% na concentração de 0,4% em 24 horas, percentual que representa 95% da hidrólise total no leite materno. Conclusões: em todas as amostras analisadas de diferentes mães, foi possível obter leite materno com baixas concentrações de lactose 24 horas após ser submetido à ação da beta galactosidase, como alternativa para bebês intolerantes à lactose e não os privar de todos os outros benefícios oferecidos por esse alimento ideal.
Sujet(s)
Femelle , Grossesse , Allaitement naturel , Lactase-phlorizin hydrolase , Lactose , Intolérance au lactose , Lait humainRÉSUMÉ
Homeopathy is highly controversial. The main reason for this is its use of very highly dilute medicines (high homeopathic potencies, HHP), diluted beyond the Avogadro/Loschmidt limit. Research using Nano Tracking Analysis has demonstrated the presence of particles in HHPs. This study aims to verify the results of a previous publication that identified the ionic composition of these particles in all dilutions. We used Scanning Electron Microscopy & Energy Dispersive X-Ray Spectroscopy (SEM-EDX) to examine dilutions of a commonly used homeopathic medicine, an insoluble metal, Cuprum metallicum, for the presence of particles (NPs). The homeopathic medicines tested were specially prepared according to the European pharmacopoeia standards. We compared the homeopathic dilutions/dynamizations of copper with simple dilutions and dynamized lactose controls. We observed an ionic diversity common to all preparations including HHPs but also significant differences in the relative quantity of each ion between manufacturing lines of homeopathic copper and lactose controls. The probability that the observed differences could have occurred chance alone (especially above Avogadro limit) can be rejected at p < 0.001. The essential component of these homeopathic medicines is sodium hydrogen carbonate, modulated by some other elements and by its quantity, size and shape. Homeopathic medicines made of Cuprum metallicum do contain material with a specific ionic composition even in HHPs diluted beyond the Avogadro/Loschmidt limit. This specificity can be attributed to the manufacturing process. This material demonstrates that the step-by-step process (dynamized or not) does not match the theoretical expectations of a dilution process. The starting material and dilution/dynamization method influences the nature of these NPs. Further measurements are needed on other raw materials using the same controls (solvent and simply diluted manufacturing lines) to support these findings. The role of sodium bicarbonate must be carefully studied in the future.
Sujet(s)
Dynamisation , Pharmacotechniques Homéopathiques , Nanoparticules , Spectrométrie d'émission X , Microscopie électronique à balayage , Cuprum , Hydrogénocarbonate de sodium , Cuivre , LactoseRÉSUMÉ
RESUMEN Objetivo: Determinar el efecto del consumo de 3 tipos de leche de vaca (sin lactosa, alta en proteínas y estándar) sobre carga glicémica (CG), respuesta glicémica (RG) e índice glicémico (IG) y el nivel de saciedad en adultos sanos. Metodología: En 11 sujetos sanos se aplicó la metodología propuesta por la norma ISO 26642 para determinar índice glicémico. Se obtuvo muestra de sangre capilar a los 0, 30, 45, 60, 90 y 120 minutos. Se evaluó el nivel de hambre, saciedad y plenitud mediante escala visual análoga (EVA). El análisis estadístico se hizo mediante Test de Friedman, Wilcoxon, ajustado por Bonferroni o ANOVA de medidas repetidas. Significancia estadística con valor p0,05). Conclusión: Si bien la leche sin lactosa presentó un alto índice glicémico, ésta no afectó el nivel de saciedad. Por otro lado, la leche alta en proteínas y estándar tienen un bajo índice glicémico.
ABSTRACT Objective: To determine the effect of consumption of 3 types of cow's milk (lactose free, high in protein, and standard) on glycemic load (GL), glycemic response (GR) and glycemic index (GI) and the level of satiety in healthy adults. Methodology: Eleven healthy subjects participated. The methodology proposed by the ISO 26642 standard was applied to determine GI. Capillary blood sample was obtained at 0, 30, 45, 60, 90 and 120 minutes. The level of hunger, satiety and fullness were evaluated using a visual analog scale (VAS). Statistical analysis was done using the Friedman, Wilcoxon test, adjusted by Bonferroni or repeated measures ANOVA. Statistical significance was set as p0.05). Conclusion: Although lactose-free milk had a high GI, it did not affect satiety. On the other hand, high protein and standard milk have a low GI.
RÉSUMÉ
La lactosa es el principal carbohidrato de la leche materna. Es un disacárido conformado por glucosa y galactosa. Su producción en la glándula mamaria es independiente de la dieta materna. Además de proveer energía, es la única fuente de galactosa de la dieta, necesaria para la síntesis de macromoléculas como oligosacáridos, glicoproteínas y glicolípidos. Favorece la absorción y retención de calcio, magnesio y cinc. Su digestión por la enzima lactasa y posterior absorción tienen lugar en intestino delgado. El déficit de lactasa, que puede ser primario congénito (muy infrecuente), primario tardío o secundario por lesión intestinal, puede generar intolerancia con síntomas como dolor, distensión abdominal, flatulencia y diarrea. En el colon, bifidobacterias y lactobacilos pueden hidrolizarla. El manejo nutricional de la intolerancia deberá hacerse siempre preservando la lactancia materna. La reducción o suspensión de la lactosa deberá ser transitoria y se reemplazarán alimentos suspendidos por otros con adecuados aportes calóricos, proteicos y de minerales y vitaminas.
Lactose is the main carbohydrate present in humanmilk. It is a disaccharide made up of glucoseand galactose. It is produced in the mammaryglands, regardless of maternal diet. In addition toproviding energy, it is the only source of dietarygalactose, necessary for macromolecule synthesis,including oligosaccharides, glycoproteins, andglycolipids. It favors calcium, magnesium, andzinc absorption and retention. Its digestion bylactase and subsequent absorption occurs inthe small intestine. Lactase deficiency may beclassified into congenital primary (very rare),late-onset primary or secondary due to an injuryof the intestine; it may cause intolerance withpain, abdominal distension, abdominal gas, anddiarrhea. In the colon, it may be hydrolyzed bybifidobacteria and lactobacilli. The nutritionalmanagement of intolerance should alwayspreserve breastfeeding. Lactose reduction orelimination should be transient, and eliminatedfood should be replaced with other similar incalorie, protein, mineral, and vitamin content.
Sujet(s)
Humains , Intolérance au lactose/diagnostic , Lactase/métabolisme , Régime alimentaire , Lactose/métabolisme , Lait humain/métabolismeRÉSUMÉ
@#Introduction: People with lactose intolerance are suggested to consume dietary items containing less lactose, such as goat’s milk. This study aimed to investigate the effects of goat’s milk powder on the health of lactose intolerant middle-aged adults. Methods: A total of 60 subjects were recruited into this randomised controlled trial. They were divided into four groups and received different dietary interventions (goat’s milk, goat’s milk with curcumin, goat’s milk with coffee, lactose-free milk) for five weeks. Health effects were compared between pre- and post-intervention. Anthropometric and biochemical parameters (blood glucose, insulin, lipid profile, C-reactive protein, and lactoferrin) were evaluated. Dietary intake was recorded using a food record. Results: Fifty-one lactose intolerant subjects completed the study. After ingestion of goat’s milk, there were significant reductions in body fat (p=0.033) and a significant increase in the percentage of muscle (p=0.021). Waist circumference (WC) decreased in both the goat’s milk with curcumin and goat’s milk with coffee groups (p<0.05 for all). Unfortunately, high-density lipoprotein cholesterol (HDL-C) dropped after the five-week intervention in the goat’s milk group (p=0.002). Lactoferrin level of the goat’s milk group was higher than other groups at post-intervention (p<0.001). Besides, the goat’s milk with coffee group seemed to consume more carbohydrates after completing the intervention (p=0.034). Conclusion: A five-week intake of goat’s milk reduced the risk of abdominal obesity among middle-aged adults. In addition, it resulted in improved lactoferrin levels.
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O objetivo deste trabalho foi preparar e caracterizar nanocarreadores via auto-organização a partir da pectina de citros e lisozima para o encapsulamento da ß-lactose. Foram estudadas três condições de interação entre os biopolímeros variando a razão molar pectina/lisozima (3:1, 2:1, 1:1, 1:2 e 1:3), o pH e o tempo de aquecimento. A confirmação da interação foi determinada por espectroscopia no infravermelho por transformada de Fourier (FTIR) e por calorimetria de varredura diferencial (DSC). Os espectros de infravermelho evidenciaram que ligações de hidrogênio foram as principais forças envolvidas na formação dos nanocarreadores e sugeriram a ausência de ß-lactose livre na superfície das nanopartículas. Os termogramas evidenciaram que as nanopartículas formadas na presença de ß-lactose têm maior estabilidade térmica do que as nanopartículas sem ß-lactose. Para ambas as formulações estudadas, na presença e na ausência de ß-lactose, a formação das nanopartículas ocorreu entre os valores de pKa e ponto isoelétrico (pI) da pectina e lisozima, respectivamente, sendo a melhor razão de interação pectina/lisozima 1:2, em pH 10, a 80 ºC por 30 min. As nanopartículas foram formadas via auto-organização e todos as partículas apresentaram distribuição de tamanho homogênea, formato esférico, diâmetro inferior a 100 nm e carga superficial negativa. A morfologia e o tamanho das partículas pouco alteraram com a incorporação da -lactose. A eficiência de encapsulação (EE) da ß-lactose foi superior a 96% para as concentrações estudadas. Ensaios preliminares in vitro, em células epiteliais de câncer de cólon (HCT-116), evidenciaram que as nanopartículas formadas são capazes de adentrar no meio intracelular, possivelmente, por via endocitose
This work aimed to prepare and characterize nanocarriers via self-assembly using citrus pectin and lysozyme for ß-lactose encapsulation. Three interaction conditions between the biopolymers were studied, varying the pectin/lysozyme molar ratio (3:1, 2:1, 1:1, 1:2 and 1:3), pH and heating time. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) determined the interaction's confirmation. The infrared spectra showed that hydrogen bonds were the main forces involved in the formation of nanocarriers and suggested the absence of free ß-lactose on the surface of the nanoparticles. The thermograms showed that nanoparticles formed in the presence of ß-lactose have greater thermal stability than nanoparticles without ß-lactose. For both formulations studied, in the presence and absence of lactose, the formation of nanoparticles occurred between the pKa and isoelectric point (pI) values of pectin and lysozyme, respectively, with the best pectin/lysozyme interaction molar ratio 1:2, at pH 10, at 80 °C for 30 min. Nanoparticles were formed via self-assembly, and all particles presented homogeneous size distribution, spherical shape, diameter less than 100 nm, and negative surface charge. The morphology and size of the particles changed little with the incorporation of ß-lactose. The encapsulation efficiency (EE) of ß-lactose was higher than 96% for the concentrations studied. Preliminary in vitro assays in colon cancer epithelial cells (HCT-116) showed that the nanoparticles formed are capable of entering the intracellular medium, possibly via endocytosis
Sujet(s)
Lysozyme/analyse , Pectine/analyse , Biopolymères/effets indésirables , Calorimétrie , Calorimétrie différentielle à balayage/méthodes , Spectroscopie infrarouge à transformée de Fourier/méthodes , Tumeurs du côlon , Nanoparticules , Concentration en ions d'hydrogène , LactoseRÉSUMÉ
Introdução: A intolerância à lactose é síndrome decorrente da má digestão do dissacarídeo lactose por deficiência da enzima lactase, gerando sintomas principalmente gastrintestinais. Ela envolve 4 causas principais: deficiência congênita de lactase; deficiência de lactase de desenvolvimento; intolerância primária à lactose; e deficiência secundária à lactase. Objetivo: Revisão da apresentação clínica da intolerância à lactose e os principais métodos disponíveis para seu diagnóstico clínico. Método: Revisão narrativa da base de dados PubMed, por meio das palavras-chave "lactose intolerance" e "genetic test" utilizando o descritor boleano and. Foram incluídos somente artigos em língua inglesa e publicados entre os anos de 2017 e 2022, totalizando 8 artigos. Resultado: O diagnóstico de intolerância à lactose relaciona-se com o seu tipo e utiliza-se dos principais métodos: teste oral de tolerância à lactose, teste genético, teste do hidrogênio expirado. Conclusão: Quanto aos métodos de diagnóstico, o teste do hidrogênio expirado é o de escolha, por não ser invasivo, possuir execução fácil e baixo custo. Entretanto, ele não dispensa associação com outras técnicas diagnósticas. O teste genético também é muito útil e sua vantagem é que não há necessidade da realização do teste oral de tolerância.
Introduction: Lactose intolerance is a syndrome resulting from maldigestion of the disaccharide lactose due to lactase enzyme deficiency causing symptoms mainly gastrointestinal. It involves 4 main causes: congenital lactase deficiency; developmental lactase deficiency; primary lactose intolerance; and secondary lactase deficiency. Objective: Review of the clinical presentation of lactose intolerance and the main methods available for its clinical diagnosis. Methods: Literature review in the PubMed database, using the keywords "lactose intolerance" and "genetic test" and using the Boolean data type and. Only articles in English and published between the years 2017 and 2022 were included, totalizing 8 articles. Results: The diagnosis of lactose intolerance is related to its type and uses the main diagnostic tests: oral lactose tolerance, genetic, expired hydrogen. Conclusion: Regarding diagnostic methods, the expired hydrogen test is the one of choice, as it is not invasive, is easy to perform and has low cost. However, it does not dispense association with other diagnostic techniques. Genetic testing is also very usefull and its advantage is that there is no need to use the oral lactose tolerance test.
RÉSUMÉ
Homeopathy is highly controversial. The main reason for this is its use of very highly dilute medicines (high homeopathic potencies, HHP), diluted beyond the Avogadro/Loschmidt limit. Research using several different methods has demonstrated the presence of particles, including nanoparticles of source material, in HHPs. This study aims to verify the results of a previous publication that detected the presence of particles in all dilutions. We used the Nano Tracking Analyzer (NTA) to examine dilutions of a commonly used homeopathic medicine, an insoluble metal, Cuprum metallicum, for the presence of particles. The homeopathic medicines tested were specially prepared according to the European pharmacopoeia standards. We compared the homeopathic dilutions/dynamizations with simple dilutions and controls including a soluble medicine. We observed the presence of solid material in all preparations including HHPs (except for pure water). The measurements showed significant differences in particle sizes distribution between homeopathic manufacturing lines and controls. Homeopathic medicines do contain material with a specific size distribution even in HHPs diluted beyond the Avogadro/Loschmidt limit. This specificity can be attributed to the manufacturing and potentization process. This material demonstrates that the step-by-step process (dynamized or not) does not match the theoretical expectations in a dilution process. The starting material and dilution/dynamization method influences the nature and concentration of these NPs.
Sujet(s)
Dynamisation , Pharmacotechniques Homéopathiques , Nanoparticules , Chlorure de potassium , Cuprum , Kali Muriaticum , Cuivre , LactoseRÉSUMÉ
BACKGROUND Biosurfactants are surface active molecules produced by microorganisms which have the ability to disrupt the plasma membrane. Biosurfactant properties are important in the food, pharmaceu tical and oil industries. Lactic acid bacteria can produce cell-bound and excreted biosurfactants. RESULTS The biosurfactant-producing ability of three Lactobacillus strains was analyzed, and the effects of carbon and nitrogen sources and aeration conditions were studied. The three species of lactobacillus eval uated were able to produce biosurfactants in anaerobic conditions, which was measured as the capacity of one extract to reduce the surface tension compared to a control. The decreasing order of biosurfactant production was L. plantarum>Lactobacillus sp.>L. acidophilus. Lactose was a better carbon source than glu cose, achieving a 23.8% reduction in surface tension versus 12.9% for glucose. Two complex nitrogen sources are required for growth and biosurfactant production. The maximum production was reached at 48 h under stationary conditions. However, the highest level of production occurred in the exponential phase. Biosurfactant exhibits a critical micelle concentration of 0.359 ± 0.001 g/L and a low toxicity against E. coli. Fourier transform infrared spectroscopy indicated a glycoprotein structure. Additionally, the kinetics of fermentation were modeled using a logistic model for the biomass and the product, achieving a good fit (R2 > 0.9). CONCLUSIONS L. plantarum derived biosurfactant production was enhanced using adequate carbon and nitrogen sources, the biosurfactant is complex in structure and because of its low toxicity could be applied to enhance cell permeability in E. coli
Sujet(s)
Acide lactique/métabolisme , Lactobacillus plantarum/métabolisme , Cinétique , Acide lactique/composition chimique , Lactobacillus plantarum/composition chimique , Modèles chimiquesRÉSUMÉ
ABSTRACT BACKGROUND: Worldwide, colorectal cancer (CRC) and gastric cancer (GC) are the third and the fifth most prevalent, respectively. Diarrhea is a common symptom in patients on chemotherapy or radiotherapy treatment and can reduce treatment tolerance. Surgical resections and chemotherapy change the intestinal microbiota that can lead to lactose intolerance, small intestinal bacterial overgrowth (SIBO). OBJECTIVE: The aim of the study was to evaluate the frequency of diarrhea in patients with CRC and GC on chemotherapy with SIBO or intolerance of lactose. METHODS: This is a descriptive and observational study with patients of both sexes, over 18 years old, in treatment in the Gastro-Oncology outpatient clinic of the Federal University of São Paulo. Patients with a confirmed diagnosis of CRC or GC during chemotherapy treatment were included. To detect bacterial overgrowth and lactose intolerance, breath hydrogen test with lactulose and lactose was done. Number and aspects of the evacuations and toxicity degree were collected. For the nutritional assessment, weight and height were performed to calculate the BMI. and the Patient Generated Subjective Global Assessment (PG-SGA). RESULTS: A total of 33 patients were included, 29 with CRC and 3 with GC. Most of them were male (57.57%), mean age of 60.03±10.01 years and in chemotherapy with fluoropyrimidine and oxaliplatin (54.5%). Diarrhea was present in 57.6% and 30.3% had toxicity grade 2. According to the BMI, 78.9% were eutrophics, obese or overweight, but according to PG-SGA, 84.9% had moderate or severe nutritional risk grade. Between patients, 45% had lactose intolerance and 9% SIBO. Diarrhea grade 2-3 was observed in 66.6% of patients with SIBO and 66.7% of that with lactose intolerance. No statistical difference was observed between patients with SIBO or lactose intolerance and grade of diarrhea. CONCLUSION: Diarrhea was a frequent symptom in chemotherapy patients with gastric or colorectal cancer independent of the presence of SIBO or lactose intolerance. Surgery and chemotherapy treatment impacted in the intestinal habit of patients. Diagnosis of other causes of diarrhea may contribute to a better tolerance to treatment and quality of life.
RESUMO CONTEXTO: Mundialmente, o câncer colorretal (CCR) e gástrico (CG) são a terceira e a quinta causa de câncer mais prevalente, respectivamente. A diarreia é um sintoma comum entre os pacientes em quimioterapia ou radioterapia e pode reduzir a tolerância ao tratamento. Quimioterapia e ressecções cirúrgicas causam alterações da microbiota intestinal que podem levar a intolerância à lactose e ao supercrescimento bacteriano do intestino delgado (SBID). OBJETIVO: Avaliar a presença de diarreia nos pacientes com câncer colorretal e gástrico em quimioterapia e a presença de SBID ou intolerância à lactose. MÉTODOS: Foi realizado um estudo descritivo, observacional com pacientes ambulatoriais de ambos os sexos, maiores de 18 anos, em tratamento no ambulatório de gastro-oncologia da Universidade Federal de São Paulo. Foram incluídos pacientes com diagnóstico confirmado de CCR ou CG durante tratamento quimioterápico. Para detectar supercrescimento bacteriano e intolerância à lactose, foram realizados testes respiratórios com lactulose e lactose respectivamente. Número, aspecto das evacuações e grau de toxicidade foram coletados. Para a avaliação nutricional foram aferidos peso e altura para cálculo do IMC e para avaliação do risco nutricional foi realizada a avaliação subjetiva global produzida pelo próprio paciente (ASG-PPP). RESULTADOS: Foram incluídos 33 pacientes, 29 com CCR e 3 com CG. A maioria era do sexo masculino (57,5%) com média de idade 60,03±10,01 anos e em tratamento quimioterápico com fluoropirimidina e oxaliplatina (54,5%). Diarreia foi relatada por 57,6% dos pacientes sendo em 30% grau 2. Pelo IMC, 78,9% apresentavam eutrofia, sobrepeso ou obesidade grau 1, mas pela ASG-PPP 84,9 apresentavam risco nutricional moderado ou severo. Entre os pacientes 9% apresentavam SBID e 45% intolerância à lactose. Diarreia grau 2-3 foi observada em 66,6% daqueles pacientes com SBID e 66,7% dos com intolerância à lactose. Não encontramos diferenças estatísticas entre os pacientes com SBID ou intolerância à lactose e intensidade de diarreia. CONCLUSÃO: Diarreia foi um sintoma frequente entre os pacientes com câncer gástrico ou colorretal em quimioterapia independente da presença de SBID ou intolerância à lactose. Cirurgia e quimioterapia impactaram no hábito intestinal dos pacientes. O diagnóstico de outras causas de diarreia pode contribuir para a melhor tolerância do tratamento e qualidade de vida.
Sujet(s)
Humains , Mâle , Femelle , Adolescent , Sujet âgé , Tumeurs de l'estomac , Tumeurs colorectales/traitement médicamenteux , Intolérance au lactose/diagnostic , Qualité de vie , Tests d'analyse de l'haleine , Hydrogène , Intestin grêle , Lactose , Adulte d'âge moyenRÉSUMÉ
BACKGROUND: Phospholipase D (PLD) is used as the biocatalyst for phosphatidylserine (PS) production. In general, PLD was expressed in insoluble form in Escherichia coli. High-level soluble expression of PLD with high activity in E. coli is very important for industrial production of PLD. RESULTS: Streptomyces chromofuscus PLD coding gene was codon-optimized, cloned without signal peptide, and expressed in E. coli. The optimal recombinant E. coli pET-28a+PLD/BL21(DE3) was constructed with pET-28a without His-tag. The highest PLD activity reached 104.28 ± 2.67 U/mL in a 250-mL shake flask after systematical optimization. The highest PLD activity elevated to 122.94 ± 1.49 U/mL by feeding lactose and inducing at 20 C after scaling up to a 5.0-L fermenter. Substituting the mixed carbon source with 1.0 % (w/v) of cheap dextrin and adding a feeding medium could still attain a PLD activity of 105. 81 ± 2.72 U/mL in a 5.0-L fermenter. Fish peptone from the waste of fish processing and dextrin from the starch are both very cheap, which were found to benefit the soluble PLD expression. CONCLUSIONS: After combinatorial optimization, the high-level soluble expression of PLD was fulfilled in E. coli. The high PLD activity along with cheap medium obtained at the fermenter level can completely meet the requirements of industrial production of PLD.
Sujet(s)
Phospholipases/métabolisme , Streptomyces/enzymologie , Solubilité , Streptomyces/génétique , Température , Codon , Techniques de chimie combinatoire , Escherichia coliRÉSUMÉ
BACKGROUND: Milk whey, a byproduct of the dairy industry has a negative environmental impact, can be used as a raw material for added-value compounds such as galactooligosaccharides (GOS) synthesis by bgalactosidases. RESULTS: B-gal42 from Pantoea anthophila strain isolated from tejuino belonging to the glycosyl hydrolase family GH42, was overexpressed in Escherichia coli and used for GOS synthesis from lactose or milk whey. Crude cell-free enzyme extracts exhibited high stability; they were employed for GOS synthesis reactions. In reactions with 400 g/L lactose, the maximum GOS yield was 40% (w/w) measured by HPAEC-PAD, corresponding to 86% of conversion. This enzyme had a strong predilection to form GOS with b(1 ? 6) and b (1 ? 3) galactosyl linkages. Comparing GOS synthesis between milk whey and pure lactose, both of them at 300 g/L, these two substrates gave rise to a yield of 38% (60% of lactose conversion) with the same product profile determined by HPAEC-PAD. CONCLUSIONS: B-gal42 can be used on whey (a cheap lactose source) to produce added value products such as galactooligosaccharides.