Is insulin a satiety signal? Insulin treatment antagonises starvation-induced increases in neuropeptide Y concentrations in the arcuate nucleus of the rat

Neuropeptide Y (NPY), the most powerful appetite stimulant known, is synthesised in hypothalamic arcuate nucleus (ARC). NPY levels rise in the ARC and in appetite-regulating hypothalamic nuclei in food-deprived rats, and may drive compensatory hyperphagia in starvation. Circulating insulin levels fall in starvation and insulin deficiency has been postulated to stimulate hypothalamic NPY; this supports the suggestion that insulin acts on the brain to inhibit feeding. We tested this hypothesis by determining whether the increase in NPY in the ARC of starved rats was suppressed by insulin treatment. Adult male Wistar rats were studied. Controls (n=8) were freely-fed and two other groups were food-deprived for 72 hours, both losing 20% of initial weight (p<O.OOI vs controls). One food·deprived group n=10) received insulin (5 U/kg/day) injected subcutaneously twice daily and both other groups recieved saline. Mean blood glucose values (measured in tail-prick samples) were 5.9± 0.1 mmoVI in controls, 4.6± 0.3 mmol/l in food-deprived (p<O.OOI. vs controls) and in insulin·treated 4.4± 0.3 mmol/I (p<O.OOI vs controls; NS vs food-deprived group). Final plasma insulin levels in insulin·treated rats were higher than in saline-treated food-deprived rats (46.6± 8.9 vs 28.9± 4.5 pmol/l; p<O.OOI) and comparable with controls (52.6± 16.2 pmol/l; p=NS). ARC NPY concentrations rose significantly above controls in food·deprived rats (14.18± 1.79 vs 8.4± 2.16 fmol/ug protein; p<O.OOI) and were intermediate in the insulin-treated food-deprived group (11.19± 1.36 fmol/ug protein: p<O.OI vs controls and p<O.OOI vs saline-treated, food deprived). Other hypothalamic regions showed no differences between groups. Insulin therefore antagonises fasting·induced increases in NPY concentrations in the ARC. This is consistent with the hypotheses that insulin deficiency stimulates hypothalamic NPY synthesis, and that peripheral insulin acts as a satiety factor by inhibiting hypothalamic NPY

A soy-yoghurt-honey product as a therapeutic functional food: mode of action and narrative review

Meal replacements and food supplements are now popular commercial weight loss and nutrition products. This review describes the efficacy, effectiveness, and therapeutic use of one such product - a soy-yoghurt-honey food formulation. The original formula of this product was created more than thirty years ago and since that time it has become well established as a food supplement supporting a healthy lifestyle. Therapeutic evidence for this product is based on numerous scientific studies and clinical trials, focusing particularly on weight management and associated metabolic risk factors and published as peer-reviewed articles. Given the availability of the product and the extent to which it has been experimentally evaluated, it is timely and important that the research is brought together under a single review to consolidate the understanding for the scientific and clinical communities. This review discusses the ingredients and the broad mechanisms of action, which are probably due to the biological properties of the three base components - soy, milk, and honey. It further summarizes and discusses the laboratory and clinical intervention studies, including the biochemical and metabolic mechanisms regarding the insulin- and lipid-lowering, anti-hypertensive, anti-inflammatory, antioxidant, and anti-microbial properties of the overall food and its base products

Towards Bedmap Himalayas: development of an airborne ice-sounding radar for glacier thickness surveys in High-Mountain Asia

The thickness of glaciers in High-Mountain Asia (HMA) is critical in determining when the ice reserve will be lost as these glaciers thin but is remarkably poorly known because very few measurements have been made. Through a series of ground-based and airborne field tests, we have adapted a low-frequency ice-penetrating radar developed originally for Antarctic over-snow surveys, for deployment as a helicopter-borne system to increase the number of measurements. The manoeuvrability provided by helicopters and the ability of our system to detect glacier beds through thick, dirty, temperate ice makes it well suited to increase greatly the sample of measurements available for calibrating ice thickness models on the regional and global scale. The Bedmap Himalayas radar-survey system can reduce the uncertainty in present-day ice volumes and therefore in projections of when HMA's river catchments will lose this hydrological buffer against drought

The placental renin-angiotensin system and oxidative stress in pre-eclampsia

There is an inverse correlation between human birthweight and umbilical venous angiotensin II (AngII) concentrations. Oxidative stress and increased pro-renin receptor (PRR) both enhance the cleavage of angiotensin I from angiotensinogen (AGT). Pre-eclampsia, a hypertensive disorder of pregnancy, manifests as high blood pressure and proteinuria, and is a state of increased oxidative stress. Objectives, study design and main outcome measures Hypothesis: Pre-eclampsia will be associated with increased placental expression of components of the renin–angiotensin system, which could result in reduced infant birthweight. Biopsies were taken 1 cm from the placental edge from 27 normotensive controls and 23 pre-eclamptic White European women. Immunohistochemistry was performed for AGT, PRR, glutathione peroxidase 3 (GPx3) and the AT1R and AT2R AngII receptors. Protein expression was semi-quantitatively assessed (H-score). Results: AT1R expression was significantly increased in pre-eclamptic placentae, and negatively correlated with birthweight (r = −0.529, P = 0.009). AT1R expression was also negatively correlated with GPx3 expression overall (r = −0.647; P = 0.005). AT2R expression positively correlated with AGT (r = 0.615, P = 0.002) in the pre-eclamptic placentae only. Conclusions: The raised AT1R expression in pre-eclampsia, together with inadequate antioxidant protection, possibly through lower GPx activity, might enhance the vasoconstrictor effect of locally-generated AngII, contributing to the restricted fetal growth characteristic of pre-eclampsia. Conversely, the AT2R:AGT association within the pre-eclamptic placenta may provide a compensatory mechanism

Search for single top quarks in the tau+jets channel using 4.8 fb−1^{-1} of ppˉp\bar{p} collision data

We present the first direct search for single top quark production using tau leptons. The search is based on 4.8 fb$^{-1}$ of integrated luminosity collected in $p\bar{p}$ collisions at $\sqrt{s}$=1.96 TeV with the D0 detector at the Fermilab Tevatron Collider. We select events with a final state including an isolated tau lepton, missing transverse energy, two or three jets, one or two of them $b$ tagged. We use a multivariate technique to discriminate signal from background. The number of events observed in data in this final state is consistent with the signal plus background expectation. We set in the tau+jets channel an upper limit on the single top quark cross section of \TauLimObs pb at the 95% C.L. This measurement allows a gain of 4% in expected sensitivity for the observation of single top production when combining it with electron+jets and muon+jets channels already published by the D0 collaboration with 2.3 fb$^{-1}$ of data. We measure a combined cross section of \SuperCombineXSall pb, which is the most precise measurement to date.Comment: 12 pages, 5 figure

b-Jet Identification in the D0 Experiment

Algorithms distinguishing jets originating from b quarks from other jet flavors are important tools in the physics program of the D0 experiment at the Fermilab Tevatron p-pbar collider. This article describes the methods that have been used to identify b-quark jets, exploiting in particular the long lifetimes of b-flavored hadrons, and the calibration of the performance of these algorithms based on collider data.Comment: submitted to Nuclear Instruments and Methods in Physics Research

Search for pair production of the scalar top quark in the electron-muon final state

We report the result of a search for the pair production of the lightest supersymmetric partner of the top quark ($\tilde{t}_1$) in $p\bar{p}$ collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider corresponding to an integrated luminosity of 5.4 fb$^{-1}$. The scalar top quarks are assumed to decay into a $b$ quark, a charged lepton, and a scalar neutrino ($\tilde{\nu}$), and the search is performed in the electron plus muon final state. No significant excess of events above the standard model prediction is detected, and improved exclusion limits at the 95% C.L. are set in the the ($M_{\tilde{t}_1}$,$M_{\tilde{\nu}}$) mass plane

Measurement of the dijet invariant mass cross section in proton anti-proton collisions at sqrt{s} = 1.96 TeV

The inclusive dijet production double differential cross section as a function of the dijet invariant mass and of the largest absolute rapidity of the two jets with the largest transverse momentum in an event is measured in proton anti-proton collisions at sqrt{s} = 1.96 TeV using 0.7 fb^{-1} integrated luminosity collected with the D0 detector at the Fermilab Tevatron Collider. The measurement is performed in six rapidity regions up to a maximum rapidity of 2.4. Next-to-leading order perturbative QCD predictions are found to be in agreement with the data.Comment: Published in Phys. Lett. B, 693, (2010), 531-538, 8 pages, 2 figures, 6 table

Measurement of Z/gamma*+jet+X angular distributions in ppbar collisions at sqrt{s}=1.96 TeV

We present the first measurements at a hadron collider of differential cross sections for Z+jet+X production in delta phi(Z, jet), |delta y(Z, jet)| and |y_boost(Z, jet)|. Vector boson production in association with jets is an excellent probe of QCD and constitutes the main background to many small cross section processes, such as associated Higgs production. These measurements are crucial tests of the predictions of perturbative QCD and current event generators, which have varied success in describing the data. Using these measurements as inputs in tuning event generators will increase the experimental sensitivity to rare signals.Comment: Published in Physics Letters B 682 (2010), pp. 370-380. 15 pages, 6 figure

Search for the standard model Higgs boson in tau final states

We present a search for the standard model Higgs boson using hadronically decaying tau leptons, in 1 inverse femtobarn of data collected with the D0 detector at the Fermilab Tevatron ppbar collider. We select two final states: tau plus missing transverse energy and b jets, and tau+ tau- plus jets. These final states are sensitive to a combination of associated W/Z boson plus Higgs boson, vector boson fusion and gluon-gluon fusion production processes. The observed ratio of the combined limit on the Higgs production cross section at the 95% C.L. to the standard model expectation is 29 for a Higgs boson mass of 115 GeV.Comment: publication versio