L-Arginine promotes gut hormone release and reduces food intake in rodents

Aims: To investigate the anorectic effect of L‐arginine (L‐Arg) in rodents. Methods: We investigated the effects of L‐Arg on food intake, and the role of the anorectic gut hormones glucagon‐like peptide‐1 (GLP‐1) and peptide YY (PYY), the G‐protein‐coupled receptor family C group 6 member A (GPRC6A) and the vagus nerve in mediating these effects in rodents. Results: Oral gavage of L‐Arg reduced food intake in rodents, and chronically reduced cumulative food intake in diet‐induced obese mice. Lack of the GPRC6A in mice and subdiaphragmatic vagal deafferentation in rats did not influence these anorectic effects. L‐Arg stimulated GLP‐1 and PYY release in vitro and in vivo. Pharmacological blockade of GLP‐1 and PYY receptors did not influence the anorectic effect of L‐Arg. L‐Arg‐mediated PYY release modulated net ion transport across the gut mucosa. Intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) administration of L‐Arg suppressed food intake in rats. Conclusions: L‐Arg reduced food intake and stimulated gut hormone release in rodents. The anorectic effect of L‐Arg is unlikely to be mediated by GLP‐1 and PYY, does not require GPRC6A signalling and is not mediated via the vagus. I.c.v. and i.p. administration of L‐Arg suppressed food intake in rats, suggesting that L‐Arg may act on the brain to influence food intake. Further work is required to determine the mechanisms by which L‐Arg suppresses food intake and its utility in the treatment of obesity

Development of a technique to minimise the wind-induced noise in shielded microphones

S.V. Alamshah, A.C.Zander, V.V. Lenchinehttp://www.acoustics.asn.au/conference_proceedings/AAS2013/papers/AAS2013-Information.pdfhttp://www.acoustics.asn.au/conference_proceedings/AAS2013

Prosthetic hemodialysis access-induced distal hand ischemia and its contributors in diabetics

Avoidance of hand ischemia in the construction of prosthetic access for hemodialysis in diabetics that have no suitable vein for arteriovenous fistula is appreciated. Taper type may be an appropriately matched conduit to prevent its occurrence. This is a prospective controlled trial of 38 selected diabetics requiring hemodialysis, who were referred to our clinic during a period of 6 months. The aim of the study was to evaluate the efficacy of tapered grafts in preventing distal hand hypoperfusion and determining its most likely contributors. In 18 intervening cases, taper 4 mm × 7 mm and in twenty cases (control group), standard 6 mm polytetrafluoroethylene as straight Brachial-Axillary access was used. Graft flow rates, artery and vein diameters, and mean arterial pressure were included for evaluation. Within the control group, 11 patients (55%) (7 cases Grade 1, 3 Grade 2, 1 Grade 3) and in intervening group, 2 cases (11%) (Grade 1, Grade 3) developed Steal syndrome. There was no significant difference in the mean flow rates (P = 0.82). Increased risk of distal hypoperfusion was observed in the control group when flow rates were more than 1000 ml/min. Arterial diameters (P = 0.011) and mean arterial pressure (P = 0.05) were found to be important contributing factors. Taper grafts causes reduced incidence of distal hand hypoperfusion. When artery diameter was <6 mm and mean arterial pressure lower than 100 mmHg and the index (brachial artery diameter × mean arterial pressure) was under 500, distal hand ischemia occurred in standard and tapper type. We therefore recommend selective usage of taper grafts in diabetics with diminished distal hand pulses, considering the contributing factors when fistula first is not feasible

L-Arginine increases post-prandial circulating GLP-1 and PYY levels in humans

Objective The satiating effect of protein compared with other nutrients has been well described and is thought to be mediated, in part, by gut hormone release. Previously, it has been shown that oral L‐arginine acts as a GLP‐1 secretagogue both in vitro and in vivo in rodents. Here, the effect of L‐arginine on gut hormone release in humans was investigated. Methods The hypothesis was tested in two separate studies. The first study assessed the tolerability of oral L‐arginine in healthy human subjects. The second study assessed the effect of oral L‐arginine on gut hormone release following an ad libitum meal. Subjects were given L‐arginine, glycine (control amino acid), or vehicle control in a randomized double‐blind fashion. Results At a dose of 17.1 mmol, L‐arginine was well tolerated and stimulated the release of plasma GLP‐1 (P < 0.05) and PYY (P < 0.001) following an ad libitum meal. Food diaries showed a trend toward lower energy intake and particularly fat intake following L‐arginine treatment. Conclusions L‐arginine can significantly elevate GLP‐1 and PYY in healthy human volunteers in combination with a meal. Further work is required to investigate whether L‐arginine may have utility in the suppression of appetite and food intake

The homeostatic dynamics of feeding behaviour identify novel mechanisms of anorectic agents

Better understanding of feeding behaviour will be vital in reducing obesity and metabolic syndrome, but we lack a standard model that captures the complexity of feeding behaviour. We construct an accurate stochastic model of rodent feeding at the bout level in order to perform quantitative behavioural analysis. Analysing the different effects on feeding behaviour of PYY3-36, lithium chloride, GLP-1 and leptin shows the precise behavioural changes caused by each anorectic agent. Our analysis demonstrates that the changes in feeding behaviour evoked by the anorectic agents investigated do not mimic the behaviour of well-fed animals, and that the intermeal interval is influenced by fullness. We show how robust homeostatic control of feeding thwarts attempts to reduce food intake, and how this might be overcome. In silico experiments suggest that introducing a minimum intermeal interval or modulating upper gut emptying can be as effective as anorectic drug administration

L‐arginine promotes gut hormone release and reduces food intake in rodents

Aims: To investigate the anorectic effect of L‐arginine (L‐Arg) in rodents. Methods: We investigated the effects of L‐Arg on food intake, and the role of the anorectic gut hormones glucagon‐like peptide‐1 (GLP‐1) and peptide YY (PYY), the G‐protein‐coupled receptor family C group 6 member A (GPRC6A) and the vagus nerve in mediating these effects in rodents. Results: Oral gavage of L‐Arg reduced food intake in rodents, and chronically reduced cumulative food intake in diet‐induced obese mice. Lack of the GPRC6A in mice and subdiaphragmatic vagal deafferentation in rats did not influence these anorectic effects. L‐Arg stimulated GLP‐1 and PYY release in vitro and in vivo. Pharmacological blockade of GLP‐1 and PYY receptors did not influence the anorectic effect of L‐Arg. L‐Arg‐mediated PYY release modulated net ion transport across the gut mucosa. Intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) administration of L‐Arg suppressed food intake in rats. Conclusions: L‐Arg reduced food intake and stimulated gut hormone release in rodents. The anorectic effect of L‐Arg is unlikely to be mediated by GLP‐1 and PYY, does not require GPRC6A signalling and is not mediated via the vagus. I.c.v. and i.p. administration of L‐Arg suppressed food intake in rats, suggesting that L‐Arg may act on the brain to influence food intake. Further work is required to determine the mechanisms by which L‐Arg suppresses food intake and its utility in the treatment of obesity