Incubation of NAD(P)H2: glutathione oxidoreductase (EC 1.6.4.2) with flavin adenine dinucleotide for maximal stimulation in the measurement of riboflavin status

Immunological significance of prognostic alternative splicing signature in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) ranks the sixth prevalent tumors with high mortality globally. Alternative splicing (AS) drives protein diversity, the imbalance of which might act an important factor in tumorigenesis. This study aimed to construct of AS-based prognostic signature and elucidate the role in tumor immune microenvironment (TIME) and immunotherapy in HCC.

METHODS

Univariate Cox regression analysis was performed to determine the prognosis-related AS events and gene set enrichment analysis (GSEA) was employed for functional annotation, followed by the development of prognostic signatures using univariate Cox, LASSO and multivariate Cox regression. K-M survival analysis, proportional hazards model, and ROC curves were conducted to validate prognostic value. ESTIMATE R package, ssGSEA algorithm and CIBERSORT method and TIMER database exploration were performed to uncover the context of TIME in HCC. Quantitative real-time polymerase chain reaction was implemented to detect ZDHHC16 mRNA expression. Cytoscape software 3.8.0 were employed to visualize AS-splicing factors (SFs) regulatory networks.

RESULTS

A total of 3294 AS events associated with survival of HCC patients were screened. Based on splicing subtypes, eight AS prognostic signature with robust prognostic predictive accuracy were constructed. Furthermore, quantitative prognostic nomogram was developed and exhibited robust validity in prognostic prediction. Besides, the consolidated signature was significantly correlated with TIME diversity and ICB-related genes. ZDHHC16 presented promising prospect as prognostic factor in HCC. Finally, the splicing regulatory network uncovered the potential functions of splicing factors (SFs).

CONCLUSION

Herein, exploration of AS patterns may provide novel and robust indicators (i.e., risk signature, prognostic nomogram, etc.,) for prognostic prediction of HCC. The AS-SF networks could open up new approach for investigation of potential regulatory mechanisms. And pivotal players of AS events in context of TIME and immunotherapy efficiency were revealed, contributing to clinical decision-making and personalized prognosis monitoring of HCC.

Effects of methodological variation on assessment of riboflavin status using the erythrocyte glutathione reductase activation coefficient assay

Riboflavin status is usually measured as thein vitrostimulation with flavin adenine dinucleotide of the erythrocyte enzyme glutathione reductase, and expressed as an erythrocyte glutathione reductase activation coefficient (EGRAC). This method is used for the National Diet and Nutrition Surveys (NDNS) of the UK. In the period between the 1990 and 2003 surveys of UK adults, the estimated prevalence of riboflavin deficiency, expressed as an EGRAC value ≥ 1·30, increased from 2 to 46 % in males and from 1 to 34 % in females. We hypothesised that subtle but important differences in the detail of the methodology between the two NDNS accounted for this difference. We carried out an evaluation of the performance of the methods used in the two NDNS and compared against an ‘in-house’ method, using blood samples collected from a riboflavin intervention study. Results indicated that the method used for the 1990 NDNS gave a significantly lower mean EGRAC value than both the 2003 NDNS method and the ‘in-house’ method (P < 0·0001). The key differences between the methods relate to the concentration of FAD used in the assay and the duration of the period of incubation of FAD with enzyme. The details of the EGRAC method should be standardised for use in different laboratories and over time. Additionally, it is proposed that consideration be given to re-evaluating the basis of the EGRAC threshold for riboflavin deficiency.

Increase in selenium requirements with physical activity loads in well-trained athletes is not linear

Selenium requirements in athletes are supposed to be increased with energy expenditure (EE) to preserve selenium status and an optimal antioxidant balance. The question of whether selenium intakes are related to EE and whether plasma selenium status induces up-regulation in erythrocyte endogenous antioxidant defense and decreases plasma oxidative damage markers in athletes was addressed. 118 well-trained athletes completed 7 d food and activities records in a cross-sectional study. Blood was sampled on day 8. Among the athletes, 23% of the males and 66% of the females had selenium intakes below two-third of the French RDA. Plasma selenium concentrations in most of less trained athletes were lower than the postulated concentration to be required to maximize erythrocyte GSH-Px activity. Athletes with the highest daily EE had the highest selenium intakes, percentage of vegetal protein intakes and plasma selenium concentrations. Only 2.6% of the athletes exhibited low plasma selenium concentrations (< 0.75 micromol/l). The relation between plasma selenium and EE was polynomial (r = 0.50; P < 0.005). Erythrocyte GSH-Px activity in athletes was not linked to selenium status. Selenium requirements are increased in athletes without being linearly related to EE.

Selenium status in an iodine deficient population of the West Ivory Coast

Selenium is an essential trace element which is part of the active site of seleno-dependent glutathione peroxidase and type 1 deiodinase. Therefore, it plays a key role in thyroid hormone metabolism. The present work was undertaken in order to evaluate selenium status in two Ivory Coast populations: the first with high (Glanlé) and the second with low (Abidjan) prevalence of iodine deficiency. Selenium, glutathione peroxidase, glutathione reductase, glutathione and diglutathione were determined in blood and/or urine. In plasma and erythrocytes, selenium and glutathione peroxidase were dramatically low in Glanlé. Compared to Abidjan, selenium, glutathione peroxidase, vitamin E and riboflavin status were decreased whereas diglutathione was increased in Glanlé. The results clearly demonstrate a selenium deficiency and suggest an oxidant stress in Glanlé. Causes and consequences of this selenium deficiency and oxidant stress remain to be determined.

Adaptation of coenzyme stimulation assays for the nutritional assessment of vitamins B1, B2 and B6 using the Cobas Bio centrifugal analyser

Adaptation of coenzyme stimulation assays for the nutritional assessment of thiamine, riboflavin and pyridoxine on the Cobas Bio centrifugal analyser are described. Whole blood was collected into acid-citrate dextrose, which preserves the erythrocytes, prior to assay for several days. Washed erythrocytes stored at -70 degrees C and subsequently thawed, showed altered enzyme activities. The methods offer improved precision over existing procedures and take advantage of the high throughput capabilities of the instrumentation.

Comparison of riboflavin, vitamin A, and zinc status of Chinese populations at high and low risk for esophageal cancer

In two surveys in The Peoples Republic of China, blood samples were collected for nutritional studies in two counties where the risks of esophageal cancer are very different. The first survey was done in May 1980 in Linxian County (Henan Province) where the risk of esophageal cancer is very high. Blood samples were obtained from 111 persons (58 men, 53 women) who were selected randomly from 528 subjects that underwent endoscopical examination. The second survey was done in May 1981 in Jiaoxian County (Shandong Province) where the risk of esophageal cancer is reported to be relatively low. Blood samples were obtained from 120 persons (66 men, 54 women) who were selected randomly from 252 subjects that had also had undergone endoscopy. The blood samples were used to measure the nutritional status of riboflavin (erythrocyte glutathione reductase activation coefficient), vitamin A (retinol and carotene concentrations), and zinc (plasma and hair zinc concentrations). Only riboflavin status was significantly different in the two communities. The distribution of erythrocyte glutathione reductase activation coefficient values suggested that riboflavin status was much better in the low-risk community. Also in May 1981, a few more blood samples were obtained from some of the participants of the previous year's study in Linxian. A slight improvement in riboflavin and zinc status was detected. We considered the possibility that these changes may have been linked to the socioeconomic changes currently taking place in rural areas. Data were also collected from food allocation records in 15 production brigades in Linxian and 13 production brigades in Jiaoxian in the same years. The records used represented the food consumption of 3,491 and 2,552 persons, respectively, and were used to calculate daily food and nutrient intakes in the two communities. Dietary analyses highlighted the vegetarian nature of the diet, the low consumption of riboflavin, and the virtual dependence on carotene for vitamin A. Both communities consumed very little in the way of animal products or fruit, but intake of these items was higher in Jiaoxian.