Fluid movement and availability following ingestion of glucose solutions at rest and after exercise

The consequences of ingesting different carbohydrate solutions on fluid movement and availability have not been systematically examined. In addition, the role of carbohydrate in the post-exercise rehydration period has received little attention despite the need for substrate replenishment following exercise and the role of carbohydrates in stimulating water absorption in the intestine. The aims of this thesis were to assess fluid absorption characteristics and availability of solutions containing increasing concentrations of glucose and to evaluate their role in the restoration and maintenance of fluid balance following a period of exercise-induced dehydration. The ingestion of a single bolus of a commercially available hypertonic 18% carbohydrate solution (chapter 3) and a hypertonic 10% glucose solution (chapter 4) resulted in reductions in plasma volume that are most likely due to acute net secretion of water into the intestinal lumen. When investigating recovery of whole body hydration status after sweat loss, a hypertonic 10% glucose-electrolyte solution maintained whole body fluid balance for a longer period than a hypotonic 2% glucose-electrolyte solution and an electrolyte only solution when a fixed volume of fluid was consumed during a rehydration period of one hour following cycle exercise in the heat (chapter 5). When fluid was consumed ad libitum over a two hour period following similar cycle exercise in the heat, a hypertonic 10% glucose-electrolyte solution was as effective in restoring and maintaining fluid balance as a 2% hypotonic glucose-electrolyte solution and an electrolyte only solution (chapter 6). The reduced rate of gastric emptying that accompanies the ingestion of high carbohydrate solutions was likely to be the primary cause for the difference in urine production reported between thetrials during this study (chapter 7). In conclusion, ingestion of hypertonic carbohydrate solutions results in a reduction in extracellular fluid volume that is most likely due to secretion of water into the intestinal lumen and the carbohydrate content of an ingested solution is of importance in the post-exercise rehydration period.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Sexual conflict over mating in lygaeus seed bugs

Sexual conflict has been proposed to be important for evolution, and is often implicated in population divergence and speciation through sexually antagonistic co-evolution (SAC). However, empirical tests of these ideas on field populations are few. How sexual conflict, and SAC, operates in the wild, remains an important unanswered question if we are to fully understand the role of sexual conflict in evolution in nature. Here, I studied sexual conflict over mating in the seed feeding bugs Lygaeus equestris and Lygaeus simulans. Firstly, I show that laboratory adapted populations of L. equestris that differ in the magnitude of sexual conflict also differ in aspects of their reproductive development and mating propensity, with the population displaying greater conflict load also mating more readily. Study of female receptivity to mating as an evolvable trait, that could be involved in conflict over mating, revealed moderate to low heritability at two age groups. To better understand variation in the expression of sexual conflict in the wild, field caught populations of L. equestris, ranging across its distribution, and also of its sister species, L. simulans, were assayed for the magnitude of sexual conflict over mating in common garden laboratory experiments. High female mating costs were apparent across the populations, but the magnitude of these costs did not vary. No consistent patterns of mating costs and life history variation were found however, arguing against close links between mating costs and life-history. Finally, I investigated whether populations displaying sexual conflict over mating have begun to diverge, and evolve reproductive isolation. I found no evidence of reproductive isolation, or variation in mating propensity, between populations of L. equestris when crossed in reciprocal no-choice mating trials. However, L. equestris and L. simulans did show pre-zygotic reproductive isolation albeit with asymmetries between the reciprocal crosses (L. simulans males were able to mate L. equestris females, but male L. equestris were largely unable to mate L. simulans females). As expected for close taxa that perhaps have not been diverged for long, pre-zygotic isolation was perhaps stronger than post-zygotic isolation, as F2 offspring were generated by some of the inter-specific crosses: gene flow can therefore occur between these species contrary to previous studies. My data suggest that sexual conflict over mating may reduce the likelihood of speciation through the evolution of male persistence, as well as promote it through population divergence

The Journal of the Friend's Historical Society vol. 67

01 Editorial; 02 'Providing a Moral Compass for the British People': The work of Joseph Tregelles Price, Evan Rees and The Herald of Peace; 03 John Edward Southall: Quaker and Welshman; 04 No 'Friends' of Home Rule?; 05 Mary Elmes (1908-2002), the first Irish 'Righteous'; 06 Recent Publications; 07 Biographies

The effect of glucose or fructose added to a semi-solid meal on gastric emptying rate, appetite and blood biochemistry

The ingestion of fructose is of interest due to previously reported differences in gastrointestinal, appetite, and metabolic effects when compared to glucose ingestion when ingested in liquid solution. The aim of this study was to examine these variables when fructose and glucose are added to a semi-solid meal. Seven healthy male participants completed three experimental trials involving the ingestion of 300 mL of semi-skimmed milk mixed with 40 g of instant porridge mix (CON) and with the addition of either 40 g of glucose (GLU) or fructose (FRU). Subjective feelings of appetite were assessed for 2 h after ingestion with blood samples collected at regular intervals. Gastric emptying rate was assessed using the 13C breath test method. Half emptying time was not different between trials (CON = 159 ± 51 min; GLU = 197 ± 46 min; FRU = 198 ± 67 min: P = 0.117). No differences were observed for any subjective measurements of appetite (P > 0.05) while blood glucose was elevated (P < 0.05) 20 min after ingestion on both GLU and FRU with this tending to be higher on GLU than FRU. FRU resulted in greater (P < 0.05) blood lactate concentrations than on the other trials. The results of this study demonstrate that gastric emptying rate of glucose and fructose is similar when ingested in a semi-solid meal. In addition, there is little difference in appetite response between these sugars, however, there are some differences in metabolic response which deserve further study

A Comparison of Intermittent and Continuous Exercise Bouts at Different Intensities on Appetite and Postprandial Metabolic Responses in Healthy Men

Exercise intensity affects many potential postprandial responses, but there is limited information on the influence of exercise modality. Therefore, the aim of this study was to investigate if the nature of exercise at two different intensities would affect gastric emptying rate (GER), appetite and metabolic responses following ingestion of a semi-solid meal. Twelve healthy men completed, in a random order, four 60-min cycles at 60% VO2peak (MOD), 40% VO2peak (LOW) and in a continuous (CON) or intermittent (INT) manner. INT consisted of 20 × 1-min exercise bouts with 2-min rest breaks. INT and CON were matched for total work output at each intensity. GER of the post-exercise meal was measured for 2 h using the 13C-breath method. Blood glucose, substrate utilisation and appetite ratings were measured at regular intervals throughout all trials and 24-h energy intake (EI) post-trials was assessed. GER-Delta over Baseline (DOB) was lower (p 0.05). 24-h post-trial EI was similar between LOW-CON vs. LOW-INT (p > 0.05), although MOD-INT vs. MOD-CON 3500 ± 1419 vs. 2556 ± 989 kCal: p < 0.001 was elevated. In summary, MOD-INT exercise delays GER without stimulating perceived appetite in the 2 h period after meal ingestion, although EI was greater in the 24-h post-trial

The Effect of Glucose or Fructose Added to a Semi-solid Meal on Gastric Emptying Rate, Appetite, and Blood Biochemistry

The ingestion of fructose is of interest due to previously reported differences in gastrointestinal, appetite, and metabolic effects when compared to glucose ingestion when ingested in liquid solution. The aim of this study was to examine these variables when fructose and glucose are added to a semi-solid meal. Seven healthy male participants completed three experimental trials involving the ingestion of 300 mL of semi-skimmed milk mixed with 40 g of instant porridge mix (CON) and with the addition of either 40 g of glucose (GLU) or fructose (FRU). Subjective feelings of appetite were assessed for 2 h after ingestion with blood samples collected at regular intervals. Gastric emptying rate was assessed using the 13C breath test method. Half emptying time was not different between trials (CON = 159 ± 51 min; GLU = 197 ± 46 min; FRU = 198 ± 67 min: P = 0.117). No differences were observed for any subjective measurements of appetite (P &gt; 0.05) while blood glucose was elevated (P &lt; 0.05) 20 min after ingestion on both GLU and FRU with this tending to be higher on GLU than FRU. FRU resulted in greater (P &lt; 0.05) blood lactate concentrations than on the other trials. The results of this study demonstrate that gastric emptying rate of glucose and fructose is similar when ingested in a semi-solid meal. In addition, there is little difference in appetite response between these sugars, however, there are some differences in metabolic response which deserve further study

The effect of brisk walking in the fasted versus fed state on metabolic responses, gastrointestinal function, and appetite in healthy men

Objective To investigate the effect of brisk walking in the fasted versus fed state on gastric emptying rate (GER), metabolic responses and appetite hormone responses. Subjects/methods Twelve healthy men completed two 45 min treadmill walks, fasted (FASTED) and followed consumption of a standardised breakfast (FED). GER of a standardised lunch was subsequently measured for 2 h using the 13C-breath test method. Blood samples were collected at baseline, post-breakfast period, pre-exercise, immediately post exercise, pre-lunch then every 30 min following lunch for 2 h. Circulating concentrations of acylated ghrelin (GHR), glucagon-like peptide-1 (GLP-1), peptide tyrosine tyrosine (PYY), pancreatic polypeptide (PP), glucose, insulin, triglycerides, non-esterified fatty acids (NEFA) and cholesterol were measured. Subjective feelings of appetite were assessed at 15 min intervals throughout. Substrate utilisation was measured every 30 min, and continuously throughout exercise by indirect calorimetry. Results No differences were observed for GER T½ (FASTED 89 ± 22 vs. FED 89 ± 24 min, P = 0.868) nor Tlag (FASTED 55 ± 15 vs. FED 54 ± 14 min, P = 0.704). NEFA concentrations were higher in FASTED at pre-exercise, post exercise and 30 min post exercise (pre-lunch) (all P < 0.05) but no differences were observed for glucose, cholesterol or triglycerides. Carbohydrate oxidation was greater at all time-points during FED exercise (all P < 0.05). Minimal changes in appetite were observed post lunch ingestion with no differences in PYY or GHR observed between trials. GLP-1 concentrations were greater in FED post-breakfast and pre-exercise (P < 0.05), though no differences were observed after lunch. A greater concentration of PP was observed in FED from pre-exercise to 30 min post lunch consumption (all P < 0.05). Insulin concentrations were higher in FED pre-exercise but higher in FASTED 1.5 h post lunch (P < 0.05). Conclusion These findings suggest that gastrointestinal function, hunger and appetite regulatory hormones are not sensitive to low-intensity bouts of physical activity and holds positive implications for weight management practices

The effect of exercise intensity on gastric emptying rate, appetite and gut derived hormone responses after consuming a standardised semi-solid meal in healthy males

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This study investigated the acute circulating gut hormone, appetite and gastric emptying rate responses to a semi-solid meal following exercise at different intensities. Twelve men completed three trials in a randomised-crossover design, consisting of continuous cycling at 70% ˙VO2Peak(HIGH), 40% ˙VO2Peak(LOW) or rest (CONTROL). Baseline samples were collected after an overnight fast before undertaking the 60 min exercise or rest period, followed by 30 min rest before consumption of a standardised semi-solid meal (~242 kcal). During the 2 h postprandial period, gastric emptying rate of the meal was examined using the13C-breath test method, appetite was measured using visual analogue scales, and serum concentrations of acylated ghrelin, pancreatic polypeptide, peptide YY, glucagon-like peptide-1, insulin, glucose, triglycerides, total cholesterol and non-esterified fatty acids were assessed. Subjective appetite response was not different between trials (p > 0.05). Half emptying time of the meal was 89 ± 13, 82 ± 8 and 94 ± 31 min on CONTROL, LOW and HIGH, respectively (p = 0.247). In healthy un-trained adult males, responses to exercise at intensities of 70% and 40% ˙VO2Peakdid not differ to a non-exercise control for measurements of subsequent gastric emptying, circulating gut hormone response or appetite. These results suggest that exercise intensity has little effect on post-exercise appetite response to a semi-solid meal

The effect of short-term dietary fructose supplementation on gastric emptying rate and gastrointestinal hormone responses in healthy men

This study aimed to examine gastric emptying rate and gastrointestinal hormone responses to fructose and glucose ingestion following 3 days of dietary fructose supplementation. Using the 13C-breath test method, gastric emptying rates of equicaloric fructose and glucose solutions were measured in 10 healthy men with prior fructose supplementation (fructose supplement, FS; glucose supplement, GS) and without prior fructose supplementation (fructose control, FC; glucose control, GC). In addition, circulating concentrations of acylated ghrelin (GHR), glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and insulin were determined, as well as leptin, lactate, and triglycerides. Increased dietary fructose ingestion resulted in accelerated gastric emptying rate of a fructose solution but not a glucose solution. No differences in GIP, GLP-1, or insulin incremental area under curve (iAUC) were found between control and supplement trials for either fructose or glucose ingestion. However, a trend for lower ghrelin iAUC was observed for FS compared to FC. In addition, a trend of lower GHR concentration was observed at 45 min for FS compared to FC and GHR concentration for GS was greater than GC at 10 min. The accelerated gastric emptying rate of fructose following short-term supplementation with fructose may be partially explained by subtle changes in delayed postprandial ghrelin suppression

Surgical management of mediastinal liposarcoma extending from hypopharynx to carina: Case report

We describe the complete resection of a giant, well-differentiated mediastinal liposarcoma extending retropharynx to envelop the aortic arch, trachea and esophagus following preoperative radiotherapy