Relationship between sol–gel conditions and enzyme stability: a case study with β-galactosidase/silica biocatalyst for whey hydrolysis

The sol–gel process has been very useful for preparing active and stable biocatalysts, with the possibility of being reused. Especially those based on silica are well known. However, the study of the enzyme behavior during this process is not well understood until now and more, if the surfactant is involved in the synthesis mixture. This work is devoted to the encapsulation of β-galactosidase from Bacillus circulans in silica by sol–gel process, assisted by non-ionic Triton X-100 surfactant. The correlation between enzyme activity results for the β-galactosidase in three different environments (soluble in buffered aqueous reference solution, in the silica sol, and entrapment on the silica matrix) explains the enzyme behavior under stress conditions offered by the silica sol composition and gelation conditions. A stable β-galactosidase/silica biocatalyst is obtained using sodium silicate, which is a cheap source of silica, in the presence of non-ionic Triton X-100, which avoids the enzyme deactivation, even at 40 °C. The obtained biocatalyst is used in the whey hydrolysis for obtaining high value products from this waste. The preservation of the enzyme stability, which is one of the most important challenges on the enzyme immobilization through the silica sol–gel, is achieved in this study.     

The Costs of Creatinine Testing in the Context of a HIV Pre-Exposure Prophylaxis Demonstration Project in Eswatini

AIDS and Behavior - HIV treatment and prevention as well as other chronic disease care can require regular kidney function assessment based on a creatinine test. To assess the costs of creatinine...     

Exploring the safety and efficacy of adding ketoconazole to tacrolimus in pediatric renal transplant immunosuppression

BACKGROUNDGuatemala is a developing country in Central America with limited health resources. In order to expand successful renal transplant care to children and adolescents at the lowest possible cost, our pediatric renal transplant clinic uses a post-transplant tacrolimus-sparing strategy via inhibition of CYP3A4.AIMTo study the safety, efficacy and the associated cost reduction of ketoconazole in combination with tacrolimus in this pediatric population.METHODSA retrospective chart review was carried out among the cohort of pediatric renal transplant recipients treated at the Foundation for pediatric renal patients (Fundación para el Niño Enfermo Renal - FUNDANIER), a pediatric tertiary care renal transplant center in Guatemala City, Guatemala. Patient charts were reviewed to ascertain the number of transplant recipients who were transitioned from tacrolimus based immunosuppression to combination therapy with ketoconazole and tacrolimus. Twenty-five post-transplant patients that used ketoconazole combined with tacrolimus were identified. Anthropometric, clinical and laboratory data was collected from patient charts before and after the transition. RESULTSOf the 25 patient charts reviewed 12 (48%) patients were male and the average patient age was 13 years. Twenty-four (96%) transplants were from living donors. There was a non-significant difference between the mean tacrolimus doses six months and two months prior to ketoconazole: -0.10 ± 0.04 (95%CI: 0.007, -0.029), P = 0.23. However, the difference between the mean tacrolimus doses six months prior to ketoconazole initiation and six months after ketoconazole addition was significant: 0.06 ± 0.05 (95%CI: -0.034, -0.086) P < 0.001. All tacrolimus doses were reduced by 45% after the addition of ketoconazole. Therapeutic levels of tacrolimus ranged between 6.8-8.8 ng/mL during the study period and patients demonstrated an increase in estimated glomerular filtration rate. The combination of tacrolimus and ketoconazole resulted in a 21% reduction in cost.CONCLUSIONPatients experienced an effective dose-reduction of tacrolimus with the administration of ketoconazole. There was no relevant variations in tacrolimus serum levels, number of rejections, or significant liver toxicity. The strategy allowed a cost reduction in pediatric immunosuppressive therapy.     

Low-level Circulation of Enterovirus D68–Associated Acute Respiratory Infections,Germany, 2014

We used physician sentinel surveillance to identify 25 (7.7%) mild to severe infections with enterovirus D68 (EV-D68) in children and adults among 325 outpatients with acute respiratory infections in Germany during August–October 2014. Results suggested low-level circulation of enterovirus D68 in Germany. Viruses were characterized by sequencing viral protein (VP) 1 and VP4/VP2 genomic regions.     

Carob pulp preparation rich in insoluble dietary fibre and polyphenols increases plasma glucose and serum insulin responses in combination with a glucose load in humans

Dietary fibre consumption is associated with improved glucose homeostasis. In contrast, dietary polyphenols have been suggested to exert both beneficial and detrimental effects on glucose and insulin metabolism. Recently, we reported that a polyphenol-rich insoluble dietary fibre preparation from carob pulp (carob fibre) resulted in lower postprandial acylated ghrelin levels after a liquid meal challenge test compared with a control meal without supplementation. The effects may, however, differ when a different food matrix is used. Thus, we investigated the effects of carob fibre on glucose, insulin and ghrelin responses in healthy humans in combination with a glucose load. In a randomized single-blind cross-over study involving twenty healthy subjects (aged 22-62 years), plasma glucose, total and acylated ghrelin, and serum insulin were repeatedly assessed before and after the ingestion of 200 ml water with 50 g glucose and 0, 5, 10 or 20 g carob fibre over a period of 180 min. The intake of 5 and 10 g carob fibre increased the plasma glucose by 47 % and 64 % (P < 0.001), and serum insulin by 19.9 and 24.8 % (P < 0.001), compared with the control. Plasma acylated ghrelin concentrations did not change significantly after the consumption of carob-enriched glucose solution. Total ghrelin decreased only after 10 g carob fibre (P < 0.001) compared with control. In conclusion, we showed that polyphenol-rich carob fibre, administered within a water-glucose solution, increases postprandial glucose and insulin responses, suggesting a deterioration in glycaemic control.