Diabetes associated complications make management during exercise complex (Brugnara, Vinaixa, Murillo, Samino, Rodriguez, Beltran, Lerin, Davison, Correig & Novials, 2012). Research on the prevention of such challenges is of paramount importance. The aim of this study was to determine the effects of three different carbohydrate supplementation protocols on blood glucose levels after every 10 minutes of a 60 minute exercise bout at 65 to 75 % HRR on the treadmill as well as every half hour during a two hour post exercise recovery period. The three protocols implemented after a standardized pre-exercise meal were: control protocol (no carbohydrate supplementation), protocol 1 (one carbohydrate supplementation of 15 grams given at 30 minutes) and protocol 2 (two carbohydrate supplementation of 15 grams given at 30 minutes and 45 minutes). A total of 32 participants took part in the study (Mean age: 32.84 ±12.12). All participants were submitted to all three protocols. Statistical and practical significant differences were found between blood glucose levels of protocol 0 and protocol 1 (MDIF = 2.62 ± 3.99 mmol.L--‐1) at 20 minutes of the exercise duration (p=.024;d=0.42). Statistical and practical significant differences in blood glucose levels with protocol 0 rendering the higher glucose values were also found between protocols 0 and 2 at 10 minutes (MDIF = 3.44 ± 5.54 mmol.L--‐1; p=.001;d=0.62), 20 minutes (MDIF = 3.32 ± 5.23 mmol.L--‐1; p=.001;d=0.63) and 30 minutes of exercise (MDIF = 2.81 ± 5.40 mmol.L--‐1; p=.006;d=0.52) as well as between the mean minimum (M0 = 9.49 ± 4.51 mmol.L--‐1 and M2 = 7.28 ± 4.07 mmol.L--‐1; p=.013;d=0.46), mean maximum (M0 = 12.73 ± 5.51 mmol.L--‐1 and M2 = 10.07 ± 4.63 mmol.L--‐1; p=.015;d=0.46) and overall mean (M0 = 9.07 ± 4.88 mmol.L--‐1 and M2 = 8.53 ± 4.25 mmol.L--‐1; p=.011;d=0.48) with protocol 0 rendering the higher glucose values in all these comparisons. It was concluded that carbohydrate supplementation during exercise affects blood glucose levels positively particularly considering the significant difference found between protocol 0 and 2. Whilst protocol 2 also resulted in less fluctuations in the blood glucose levels during exercise and minimum, overall mean and maximum blood glucose values were closer to “normal/safe” range, there was no conclusive evidence that protocol 2 was better than protocol 1.

The purpose of this study was to determine the relationship between the overall changes in concentration of plasma pyridoxal 5'-phosphate (PLP), red blood cell PLP (rbc PLP) and plasma glucose during an oral glucose tolerance test (OGTT) in persons with diabetes mellitus (DM), and to test the hypothesis that the decrease in plasma PLP concentration that occurs with increasing plasma glucose would be explained by a subsequent increase in rbc PLP concentration. A second objective was to compare the distribution of PLP between the red blood cell and the plasma (as measured by the rbc PLP/ plasma PLP ratio) in persons with diabetes to the distribution in non-diabetic controls. The third objective was to measure fasting plasma alkaline phosphatase (AP) activity, and to compare it to fasting plasma PLP concentrations, fasting rbc PLP concentrations, and the rbc PLP/plasma PLP ratio. The purpose of this third objective was to test the hypothesis that an increased plasma AP activity in persons with DM would be associated with decreased plasma PLP and increased rbc PLP concentrations. The study included 8 persons (3F; 5M) with insulin dependent diabetes mellitus (IDDM), 9 persons (5F; 4M) with non-insulin dependent diabetes mellitus (NIDDM) and 18 healthy control individuals (9F; 9M). All subjects were given a 75 gm oral D-glucose dose, and blood was drawn at 0 (fasting), 30, 60 and 120 minutes after the glucose load. Plasma glucose, PLP, insulin, and rbc PLP concentrations were measured at all time points during the OGTT. Fasting plasma alkaline phosphatase (AP) activity, percent glycosylated hemoglobin (%GlyHb), and the ratio between fasting rbc PLP and fasting plasma PLP were also determined. In general, females with DM were in poorer diabetic control as compared to males with DM. Mean fasting glucose levels, %GlyHb and body mass index (BMI) were highest in females with DM as compared to all other groups, and fasting insulin was nearly 2x higher in females with NIDDM as compared to males with NIDDM. There was an overall decrease in plasma PLP during the OGTT with increasing plasma glucose, which agrees with results from other studies. The overall decrease in plasma PLP (as measured by the negative, cumulative area under the curve: -AUC plp) was significantly correlated with the overall increase in plasma glucose (as measured by the positive, cumulative area under the curve: +AUC glu) for all study groups. The relationship was stronger in all males, and control females as compared to females with diabetes (p< 0.001 vs. p< 0.01, respectively). This difference was in part explained by lower mean fasting PLP levels in females with DM (19.3 nmol/L), as compared to males with DM (47.2nmol/L) and male and female controls (35.4 nmol/L and 34.0 nmol/L, respectively). The changes in rbc PLP during the OGTT were minimal, and did not significantly correlate with the increase in plasma glucose or the decrease in plasma PLP. Thus, the acute drop in plasma PLP concentration that occurred during the OGTT was not explained by a subsequent increase in rbc PLP concentration, as had been hypothesized. However, the higher than normal % glycosylated hemoglobin levels along with elevated rbc PLP concentrations in persons with diabetes as compared to controls suggests that chronically elevated blood glucose can contribute to increased rbc PLP concentrations. This was the first study to date that has measured rbc PLP in persons with diabetes mellitus. Rbc PLP values for persons with DM were 20-40% greater than respective control values at all time points during the OGTT. These differences between mean rbc PLP in persons with DM as compared to control groups were all statistically significant (p< 0.05) with the exception of the difference in the mean fasting rbc PLP value for females with NIDDM as compared to controls. The mean values ± standard deviations (SD) for fasting rbc PLP (nmol/L) were as follows: Females-IDDM, 49.5 ± 6.5; NIDDM, 39.3 ± 4.9; controls, 31.4 ± 9.0; Males-IDDM, 37.8 ± 10.9; NIDDM, 45.6 ± 12.3; controls, 28.3 ± 4.4. The ratio of fasting rbc PLP concentration to fasting plasma PLP concentration was 2-3x higher in females with DM as compared to control females and all male groups. Females with IDDM had a ratio of 3.2, and the ratio for females with NIDDM was 2.2. The ratios for all male groups, and control females were approximately 1:1, with a range of 0.8-1.2. The mean fasting plasma AP activity was within the normal range for all study groups. However, females with DM had higher AP activity (0.543 μkat/L) as compared to female controls and males with DM (0.408 μkat/L, .425 μkat/L, respectively p<0.05). There were no significant differences in mean fasting plasma AP activity between any male group (range 0.390-0.465 μkat/L). These results suggest that increased plasma glucose levels, increased AP activity, and overall poor glycemic control contribute to decreased plasma PLP concentrations, increased rbc PLP concentrations, and possibly to changes in the PLP distribution within the body. / Graduation date: 1994

Call number: LD2668 .T4 1938 L51

Leung Siu Wai. / Bibliography: leaves 135-150 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1984

Digitized by Kansas Correctional Industries

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 61-67). Also available via the Internet.

Thesis (MSc (Biomedical Sciences))--Cape Peninsula University of Technology, 2018. / Background: Early detection of individuals who are at risk of developing Glucose Intolerance would decrease the morbidity and mortality associated with this disease. MicroRNA is one of the most widely studied biomolecules involved in epigenetic mechanisms, hence it offers unique opportunities in this regard. Circulating microRNAs are associated with disease pathogenesis during the asymptomatic stage of disease. This has therefore attracted a lot of attention as a potential biomarker for identifying individuals who have an increased risk of developing Glucose Intolerance. The identification of high risk biomarkers for Glucose Intolerance will go a long way to eliminate the possible complications that arise due to late diagnosis and treatment of Glucose Intolerance. This could ultimately lead to better ways to prevent, manage and control the Glucose Intolerance epidemic that is rampant worldwide. The aim of the study is to investigate expression of circulating microRNA’s in blood of mixed ancestry subjects with glucose intolerance. Methods: A quantitative cross-sectional study design involving 36 individuals [who were age, gender and BMI (Body Mass Index) matched] from a total population of 1989 participants of mixed ancestry descent, residing in Bellville South, South Africa was used. Participants were classified as controls (normoglycemic), pre-diabetic (preDM) and diabetic (DM) (screen detected diabetic) according to WHO criteria of 1998. MicroRNAs were extracted from serum using the Qiagen miRNeasy Serum/Plasma Kit (ThermoFisher). The purified micro RNAs were reverse-transcribed to cDNA (complementary deoxyribonucleic acid) using the Qiagen RT2 First Strand Kit. Then, using Qiagen miScript SYBR Green PCR kit and miScript miRNA PCR arrays (ThermoFisher), the real time polymerase chain reaction was done to determine the expression profile the circulating micro RNAs present in the serum of the participants. Results: The 36 participants were evenly divided into 3 groups of 12 participants each as mentioned earlier. There were significant differences between groups in the waist (cm) (p=0.0415) and waist/hip ratio (p=0.0011) with highest values in the DM group and lowest in the normal group. Clinical parameters varied significantly according to glycemic status. As expected, the FBG (mmol/L) (p<0.0001), 2 HRs Post Glucose (mmol/L) (p<0.0001), HbA1c (%) (p=0.0009), Fasting Insulin (mIU/L) (p=0.0039), were all highest in the DM and lowest in the control group. In contrast, the 2 HRs Post Insulin (mIU/L) (p = 0.0027) was highest in the preDM group and lowest in the normal group, while the Glucose/Insulin ratio (p=0.0477) was highest in the normal group and lowest in the preDM group. Triglycerides (mmol/L) (p=0.0043) and Total Chol (mmol/L) (p=0.0429) were significantly increased through the three groups, with highest values in the DM group and lowest in the normal group. Furthermore, 12 of the 84 miRNAs studied were expressed through all the 3 groups and they exhibited both inverse and positive correlations between the clinical parameters, especially the glucose parameters (Fasting blood glucose, 2 hours post glucose, Fasting blood insulin, 2 hours post insulin and Glycated Hemoglobin).

To determine the influence of muscle mass and absolute work on glucose tolerance and insulin sensitivity following exercise, glucose and insulin responses to an oral glucose tolerance test (OGTT) were analyzed in twelve subjects at baseline and 16 to 18 hrs following three different exercise trials performed on a cycle ergometer: 1) two-legged exercise at 60% of two-leg maximal oxygen uptake (VO2max), 2) one-legged exercise at 60% of the oneleg VO2max, and 3) a second one-leg trial at 60% of one-leg VO2max with work matched to the work obtained during the two-leg trial. Each trial was preceeded by two days of inactivity and a three day diet replication. Analysis of serum glucose concentrations during the post-exercise OGTTs demonstrated that glucose tolerance was unaffected by either the amount of active tissue incorporated in the exercise and/or the amount of work completed by the active tissue. On the other hand, serum insulin concentrations following the two-leg trial decreased 23.5% from 347.62 ±37.98 to 266.05 :L41.62 gU/ml in comparison to the one-leg trial (p < 0.05). The incorporation of a smaller muscle mass which completed an equal amount of absolute work as the larger muscle mass (i.e. one-leg work matched trial) resulted in a large (19%), but nonsignificant reduction in the total insulin compared to the one-leg relative work trial. In addition, total insulin following the two-leg and the one-leg work matched trials were reduced by 19% and 14%, respectively, in comparison to baseline. However, they did not reach statistical significance. The results of this study indicate that the incorporation of a larger muscle mass during an acute bout of aerobic exercise results in a reduction in serum insulin in response to a post-exercise oral glucose challenge. In addition, increasing the absolute work of a muscle mass results in similar reductions in serum insulin regardless of the amount of muscle mass involved in the exercise. While glucose tolerance was unaltered by either the amount of active tissue and/or the amount of work completed by the active tissue. / School of Physical Education

Considerable research has been performed on the effects of exercise and glucose tolerance, however, most of this work has examined aerobic exercise designs. This study examines the immediate post-exercise glucose turnover in eight male subjects exposed to a single bout of running and PRE. Both exercise protocols were designed to be of similar duration and at an intensity representing a typical exercise session. This study was conducted in an effort to offer individuals with NIDDM an alternative to the established aerobic forms of exercise for improved glucose control. Each subject completed two preliminary procedures, which consisted of a maximal graded exercise test and a session where a 1 RM was established on six different Cybex variable resistance machines. Subjects then completed a baseline oral glucose tolerance test (OGTT) in which eight blood samples were analyzed for glucose, insulin, hemoglobin, and hematocrit. Two exercise protocols, separated by 3 to 10 days, consisting of a 40 minute treadmill run at 75% VO2max and a 40 minute, 3 set x 10 repetition based on 75% of the1 RM, were performed and followed 45 minutes later by another OGTT. The results demonstrated that there were no apparent differences in blood glucose or insulin levels post-exercise between the exercise modes. However, the form of exercise did seem to have a varied effect on insulin production. The results of the OGTT demonstrated an explicit difference in the insulin response between the lifting and running trials, with the lifting trial being significantly higher than the resting or running trials. The increased insulin levels observed in the lifting trial may be indicative of increased secretion from the pancreas or that the secreted insulin is simply not being used. The insulin resistance observed in the lifting trial may be due to the muscles inability to respond to insulin or some other metabolic factor(s) released during exercise. Additional studies should be performed on different populations to examine the effects of PRE and running in a effort to better understand the mechanisms responsible for glucose uptake. / School of Physical Education

Studies on rat islet preparations have shown melatonin inhibits MAO activity and thereby reduces glucose mediated insulin release. The objective of this work is to investigate the effects of melatonin on insulin release, and on glucose mediated insulin release in the intact and in the pinealectomized rat.