Browsing by Subject "glucose"

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  • Surin, Alexander M.; Khiroug, Serguei; Gorbacheva, Lubov R.; Khodorov, Boris I.; Pinelis, Vsevolod G.; Khiroug, Leonard (2013)
    ATP in neurons is commonly believed to be synthesized mostly by mitochondria via oxidative phosphorylation. Neuronal mitochondria have been studied primarily in culture, i.e., in neurons isolated either from embryos or from neonatal pups. Although it is generally assumed that both embryonic and postnatal cultured neurons derive their ATP from mitochondrial oxidative phosphorylation, this has never been tested experimentally. We expressed the FRET-based ATP sensor AT1.03 in cultured hippocampal neurons isolated either from E17 to E18 rat embryos or from P1 to P2 rat pups and monitored [ATP]c simultaneously with mitochondrial membrane potential ΔΨm; TMRM) and NAD(P)H autofluorescence. In embryonic neurons, transient glucose deprivation induced a near-complete decrease in [ATP]c, which was partially reversible and was accelerated by inhibition of glycolysis with 2-deoxyglucose. In the absence of glucose, pyruvate did not cause any significant increase in [ATP]c in 84% of embryonic neurons, and inhibition of mitochondrial ATP synthase with oligomycin failed to decrease [ATP]c. Moreover, ΔΨm was significantly reduced by oligomycin, indicating that mitochondria acted as consumers rather than producers of ATP in embryonic neurons. In sharp contrast, in postnatal neurons pyruvate added during glucose deprivation significantly increased [ATP]c (by 54 ± 8%), whereas oligomycin induced a sharp decline in [ATP]c and increased ΔΨm. These signs of oxidative phosphorylation were observed in all tested P1-P2 neurons. Measurement of ΔΨm with the potential-sensitive probe JC-1 revealed that neuronal mitochondrial membrane potential was significantly reduced in embryonic cultures compared to the postnatal ones, possibly due to increased proton permeability of inner mitochondrial membrane. We conclude that, in embryonic, but not postnatal neuronal cultures, ATP synthesis is predominantly glycolytic and the oxidative phosphorylation-mediated synthesis of ATP by mitochondrial F1Fo-ATPase is insignificant. © 2013 Surin, Khiroug, Gorbacheva, Khodorov, Pinelis and Khiroug.
  • Rantapuska, Elias; Freese, Riitta Irene; Jääskeläinen, Iiro; Hytönen, Kaisa (2017)
    We build on the social heuristics hypothesis, the literature on the glucose model of self-control, and recent challenges on these hypotheses to investigate whether individuals exhibit a change in degree of trust and reciprocation after consumption of a meal. We induce short-term manipulation of hunger followed by the trust game and a decision on whether to leave personal belongings in an unlocked and unsupervised room. Our results are inconclusive. While, we report hungry individuals trusting and reciprocating more than those who have just consumed a meal in a high trust society, we fail to reject the null with small number of observations (N = 101) and experimental sessions (N = 8). In addition, we find no evidence of short-term hunger having an impact on charitable giving or decisions in public good game.
  • Miettinen, Helena E.; Rönö, Kristiina; Koivusalo, Saila; Stach-Lempinen, Beata; Pöyhönen-Alho, Maritta; Eriksson, Johan G.; Hiltunen, Timo P.; Gylling, Helena (2014)
  • Wei, Wei (Helsingin yliopisto, 2020)
    The literature review deals with the status and the causes of bread waste all over the world. More importantly, the current managements of increasing bread waste. Enzymatic hydrolysis by α-amylase and amyloglucosidase is a potential treatment, which transforms bread waste into syrups for further revaluation with functional compounds. The aim of the experimental work was to determine the influence of enzymatic hydrolysis conditions (hydrolysis time, hydrolysis temperature, enzyme dosage of α-amylase and amyloglucosidase) on glucose content and free amino nitrogen (FAN) content of resulting hydrolysate from bread waste. Furthermore, the effect of lactic acid fermentation on glucose content was studied when bread waste was subjected to simultaneous hydrolysis and fermentation with Pediococcusclaussenii (E-032355T). Glucose content varied greatly under different hydrolysis conditions from nearly 17% to only 5%, while FAN content was barely influenced. pH value had slight changes and no Bacillus cereus bacteria was found. A well fitted model for glucose content was obtained with an excellent power of interpretation, prediction and optimization. Enzyme dosage was the principal factor having a significant effect on hydrolysis efficiency, followed by temperature and time. With optimized hydrolysis conditions (50 mg/kg α-amylase and 2500 mg/kg amyloglucosidase, 30℃, 19 hours), the glucose content 16.31% was achieved, and the result was in accordance with the value 16.39% predicted by the model. Moreover, a 2.2% increase of glucose yield was detected when waste bread was subjected to simultaneous hydrolysis and fermentation compared to the control sample (bread waste was treated only with hydrolysis under the same condition). The well growth of used lactic acid bacteria (LAB) strains Pediococcusclaussenii (E-032355T) resulted in lower pH, which further improved enzymes activities and increased glucose content of the hydrolysate.
  • Satokari, Reetta (2020)
    The so-called Western diet is rich in saturated fat and sugars and poor in plant-derived fibers, and it is associated with an increased risk of metabolic and cardiovascular diseases, as well as chronic (low grade) inflammation. The detrimental effects of poor diet are in part mediated by gut microbiota, whose composition, functionality and metabolic end products respond to dietary changes. Recent studies have shown that high intake of sugars increase the relative abundance of Proteobacteria in the gut, while simultaneously decreasing the abundance of Bacteroidetes, which can mitigate the effects of endotoxin, as well as reinforce gut barrier function. Thus, a high sugar intake may stagger the balance of microbiota to have increased pro-inflammatory properties and decreased the capacity to regulate epithelial integrity and mucosal immunity. Consequently, high dietary sugar can, through the modulation of microbiota, promote metabolic endotoxemia, systemic (low grade) inflammation and the development of metabolic dysregulation and thereby, high dietary sugar may have many-fold deleterious health effects, in addition to providing excess energy.
  • Lallukka, S.; Yki-Jarvinen, H. (2016)
    Non-alcoholic fatty liver disease (NAFLD) covers a spectrum of liver disease from simple steatosis to non-alcoholic steatohepatitis (NASH) and cirrhosis. NAFLD is commonly associated with features of the metabolic/insulin resistance syndrome ('Metabolic/Obese NAFLD') and may therefore predict type 2 diabetes (T2DM). For this review, we searched for prospective studies examining whether NAFLD predicts T2DM, and if so, whether this occurs independently of factors such as age and obesity. These studies included NAFLD diagnosed by ultrasonography (n = 6) or liver enzymes (n = 14). All ultrasonography studies found NAFLD to predict the risk of T2DM independently of age, and in 4 out of 6 studies NAFLD was also a predictor independently of BMI. NAFLD was a predictor of T2DM in all 14 studies where NAFLD was diagnosed by liver enzymes. In 12 of these studies, ALT or AST or GGT were significant predictors of T2DM risk, independently of age and BMI. NAFLD, however, is heterogeneous and may also be caused by common genetic variants. The I148M variant in PNPLA3 and the E167K variant in TM6SF2 are both associated with increased liver fat content, but not features of the metabolic/insulin resistance syndrome. These genetic forms of NAFLD predict NASH and cirrhosis but not T2DM. Taken together these data imply that 'Metabolic/Obese NAFLD' predicts T2DM independently of age and obesity and support the role of hepatic insulin resistance in the pathogenesis of this disease. (C) 2016 Elsevier Ltd. All rights reserved.
  • Wu, Teddy Y.; Putaala, Jukka; Sharma, Gagan; Strbian, Daniel; Tatlisumak, Turgut; Davis, Stephen M.; Meretoja, Atte (2017)
    Background-Hyperglycemia may be associated with worse outcome after intracerebral hemorrhage (ICH). We assessed the association of early glycemic trajectory on ICH mortality and edema growth. Methods and Results-We included patients from the Helsinki ICH study with glucose measurements at least once between both 0 to 24 and 24 to 72 hours from onset. Hyperglycemia was defined as blood glucose >= 8 mmol/L (144 mg/dL) based on the local threshold for treatment. Glycemic trajectory was defined on maximum values 0 to 24 and 24 to 72 hours after ICH: (1) persistent normoglycemia in both epochs; (2) late hyperglycemia (only between 24 and 72 hours); (3) early hyperglycemia (only before 24 hours); and (4) persistent hyperglycemia in both epochs. Logistic regression with known predictors of outcome estimated the association of glycemic trajectory and 6-month mortality. A generalized linear model assessed the association of glycemic trajectory and interpolated 72-hour edema extension distance. A total of 576 patients met eligibility criteria, of whom 214 (37.2%) had persistent normoglycemia, 44 (7.6%) late hyperglycemia, 151 (26.2%) early hyperglycemia, and 167 (29.0%) persistent hyperglycemia. Six-month mortality was higher in the persistent (51.1%) and early (26.3%) hyperglycemia groups than the normoglycemia (19.0%) and late hyperglycemia (3.6%) groups. Persistent hyperglycemia was associated with 6-month mortality (odds ratio 3.675, 95% CI 1.989-6.792; P <0.001). Both univariate (P=0.426) and multivariable (P=0.493) generalized linear model analyses showed no association between glycemic trajectory and 72-hour edema extension distance. Conclusion-Early hyperglycemia after ICH is harmful if it is persistent. Strategies to achieve glycemic control after ICH may influence patient outcome and need to be assessed in clinical trials.
  • Brännback, Emilia (Helsingin yliopisto, 2020)
    Considering that dogs originate from wolves, who are carnivores, one may speculate whether high amounts of carbohydrates are beneficial to dogs’ health. The aim of this master’s thesis was to compare two different type of diets regarding glucose markers in dogs. Fasting blood samples were taken before and after a diet intervention for the analysis of blood glycosylated hemoglobin (HbA1c), glucose, insulin and glucagon concentrations to compare the differences between dogs fed a high-carbohydrate diet (dry food diet) and a diet containing no dietary carbohydrates (raw food diet). Also bodyweight was evaluated before and after the trial. This master’s thesis was part of a larger study that investigated associations between diet and atopic dermatitis in Staffordshire bull terrier dogs at the University of Helsinki. The dietary intervention lasted for 50-188 days (median 136 days). The high-carbohydrate diet contained: 42% carbohydrates, 23% proteins and 34% fats of total metabolic energy dry matter. Two different low-carbohydrate diets were used. One was a pork-chicken-lamb diet, which contained: 0%: carbohydrates, 25% proteins and 75% fats of total metabolic energy dry matter, and the other was a beef-turkey-salmon, which contained: 0% carbohydrates, 30% proteins and 70% fats of total metabolic energy dry matter. Water was allowed ad libitum. The results showed that feeding a carbohydrate-rich dry food to pet dogs for 4,5 months increased the percentage of HbA1c. In contrast, a raw food diet with low carbohydrate content did not affect the percentage of HbA1c. Both blood glucose and glucagon concentrations decreased within the raw food diet group; while they were not affected in the dry food diet group. No statistical changes in insulin concentrations were found. Based on the results of this study it can be concluded that a high-carbohydrate diet, and a low-carbohydrate, respectively, have different effects on glucose metabolism in dogs. More research is needed to understand how this affects the dog’s health.