Roux-en-Y gastric bypass surgery changes food reward in rats

Context

Roux-en-Y gastric bypass surgery (RYGB) is currently the most effective treatment for morbid obesity and clinical studies suggest that RYGB patients change food preferences and the desire to eat.

Objective

To examine hedonic reactions to palatable foods and food choice behavior in an established rat model of Roux-en-Y gastric bypass surgery (RYGB).

Methods and Design

Male Sprague-Dawley rats and selected line obesity-prone rats that were rendered obese on a high-fat diet underwent RYGB or sham surgery and were tested for ‘liking’ and ‘wanting’ of palatable foods at different caloric densities 4 – 6 months after surgery.

Results

Compared with sham-operated (obese) and age-matched lean control rats, RYGB rats of both models exhibited more positive orofacial responses to low concentrations of sucrose but fewer to high concentrations. These changes in ‘liking’ by RYGB rats were translated into a shift of the concentration-response curve in the brief access test, with more vigorous licking of low concentrations of sucrose and corn oil, but less licking of the highest concentrations. The changes in hedonic evaluation also resulted in lower long-term preference/acceptance of high-fat diets compared with sham-operated (obese) rats. Furthermore, the reduced ‘wanting’ of a palatable reward in the incentive runway seen in sham-operated obese SD rats was fully restored after RYGB to the level found in lean control rats.

Conclusions

The results suggest that RYGB leads to a shift in hedonic evaluation, favoring low over high calorie foods and restores obesity-induced alterations in ‘liking’ and ‘wanting’. It remains to be determined whether these effects are simply due to weight loss or specific changes in gut-brain communication. Given the emerging evidence for modulation of cortico-limbic brain structures involved in reward mechanisms by gut hormones, RYGB-induced changes in the secretion of these hormones could potentially be mediating these effects.

Real-life glycaemic profiles in non-diabetic individuals with low fasting glucose and normal HbA1c: the A1C-Derived Average Glucose (ADAG) study

AIMS/HYPOTHESIS

Real-life glycaemic profiles of healthy individuals are poorly studied. Our aim was to analyse to what extent individuals without diabetes exceed OGTT thresholds for impaired glucose tolerance (IGT) and diabetes.

METHODS

In the A1C-Derived Average Glucose (ADAG) study, 80 participants without diabetes completed an intensive glucose monitoring period of 12 weeks. From these data, we calculated the average 24 h glucose exposure as time spent above different plasma glucose thresholds. We also derived indices of postprandial glucose levels, glucose variability and HbA(1c).

RESULTS

We found that 93% of participants reached glucose concentrations above the IGT threshold of 7.8 mmol/l and spent a median of 26 min/day above this level during continuous glucose monitoring. Eight individuals (10%) spent more than 2 h in the IGT range. They had higher HbA(1c), fasting plasma glucose (FPG), age and BMI than those who did not. Seven participants (9%) reached glucose concentrations above 11.1 mmol/l during monitoring.

CONCLUSIONS/INTERPRETATION

Even though the non-diabetic individuals monitored in the ADAG study were selected on the basis of a very low level of baseline FPG, 10% of these spent a considerable amount of time at glucose levels considered to be 'prediabetic' or indicating IGT. This highlights the fact that exposure to moderately elevated glucose levels remains under-appreciated when individuals are classified on the basis of isolated glucose measurements.

Appetite control and energy balance regulation in the modern world: reward-driven brain overrides repletion signals

Powerful biological mechanisms evolved to defend adequate nutrient supply and optimal levels of body weight/adiposity. Low levels of leptin indicating food deprivation and depleted fat stores have been identified as the strongest signals to induce adaptive biological actions such as increased energy intake and reduced energy expenditure. In concert with other signals from the gut and metabolically active tissues, low leptin levels trigger powerful activation of multiple peripheral and brain systems to restore energy balance. It is not just neurons in the arcuate nucleus, but many other brain systems involved in finding potential food sources, smelling and tasting food, and learning to maximize rewarding effects of foods, that are affected by low leptin. Food restriction and fat depletion thus lead to a 'hungry' brain, preoccupied with food. By contrast, because of less (adaptive thrifty fuel efficiency) or lost (lack of predators) evolutionary pressure, the upper limits of body weight/adiposity are not as strongly defended by high levels of leptin and other signals. The modern environment is characterized by the increased availability of large amounts of energy-dense foods and increased presence of powerful food cues, together with minimal physical procurement costs and a sedentary lifestyle. Much of these environmental influences affect cortico-limbic brain areas concerned with learning and memory, reward, mood and emotion. Common obesity results when individual predisposition to deal with a restrictive environment, as engraved by genetics, epigenetics and/or early life experience, is confronted with an environment of plenty. Therefore, increased adiposity in prone individuals should be seen as a normal physiological response to a changed environment, not in the pathology of the regulatory system. The first line of defense should ideally lie in modifications to the environment and lifestyle. However, as such modifications will be slow and incomplete, it is equally important to gain better insight into how the brain deals with environmental stimuli and to develop behavioral strategies to better cope with them. Clearly, alternative therapeutic strategies such as drugs and bariatric surgery should also be considered to prevent or treat this debilitating disease. It will be crucial to understand the functional crosstalk between neural systems responding to metabolic and environmental stimuli, i.e. crosstalk between hypothalamic and cortico-limbic circuitry.

Site-activated chelators targeting acetylcholinesterase and monoamine oxidase for Alzheimer's therapy

Chelators have the potential to treat the underlying cause of Alzheimer's disease (AD), but their therapeutic use is hampered by their poor targeting and poor permeability to the brain and/or toxic effects. Here, we report a new strategy for designing site-activated chelators targeting both acetylcholinesterase (AChE) and monoamine oxidase (MAO). We demonstrated that our lead 2 inhibited both AChE and MAO in vitro, but with little affinity for metal (Fe, Cu, and Zn) ions. Compound 2 can be activated by inhibition of AChE to release an active chelator M30. M30 has been shown to be able to modulate amyloid precursor protein regulation and beta-amyloid reduction, suppress oxidative stress, and passivate excess metal ions (Fe, Cu, and Zn). Compound 2 was less cytotoxic and more lipophilic than the brain-permeable chelator M30. Our new strategy is relatively simple and generally produces small and simple molecules with drug-like properties; it thus holds a potential use in designing site-activated multifunctional chelators with safer and more efficacious properties for treating other metal-related diseases such as Parkinson's disease and cancer where specific elimination of metals in cancer cells is required.

Improvement of the mdx mouse dystrophic phenotype by systemic in utero AAV8 delivery of a minidystrophin gene

Duchenne muscular dystrophy (DMD) is a devastating primary muscle disease with pathological changes in skeletal muscle that are ongoing at the time of birth. Progressive deterioration in striated muscle function in affected individuals ultimately results in early death due to cardio-pulmonary failure. As affected individuals can be identified before birth by prenatal genetic testing for DMD, gene replacement treatment can be started in utero. This approach offers the possibility of preventing pathological changes in muscle that begin early in life. To test in utero gene transfer in the mdx mouse model of DMD, a minidystrophin gene driven by the human cytomegalovirus promoter was delivered systemically by an intraperitoneal injection to the fetus at embryonic day 16. Treated mdx mice studied at 9 weeks after birth showed widespread expression of recombinant dystrophin in skeletal muscle, restoration of the dystrophin-associated glycoprotein complex in dystrophin-expressing muscle fibers, improved muscle pathology, and functional benefit to the transduced diaphragm compared with untreated littermate controls. These results support the potential of the AAV8 vector to efficiently cross the blood vessel barrier to achieve systemic gene transfer to skeletal muscle in utero in a mouse model of muscular dystrophy, to significantly improve the dystrophic phenotype and to ameliorate the processes that lead to exhaustion of the skeletal muscle regenerative capacity.

Application of low-volume zero-balanced ultrafiltration and its effect on blood propofol concentration: a randomized controlled trial

AIM

The aim of this study was to evaluate the effectiveness of low-volume zero-balanced ultrafiltration during cardiopulmonary bypass in heart valve replacement surgery.

METHODS

This was a randomized, double-blind, controlled study carried out in the operating room. Forty patients of ASA grade II-III, elected to undergo heart valve replacement surgery, were enrolled. All patients were randomly assigned to either a low-volume (35 mL/kg) zero-balanced ultrafiltration group (N.=20) or to a control group (N.=20). Blood propofol concentrations and entropy index were measured using cardiopulmonary bypass. Concentrations of plasma tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), interleukin-10 (IL-10), and cardiac troponin I were measured before and after the end of cardiopulmonary bypass and corrected according to hematocrit.

RESULTS

Blood levels of cardiac troponin I, TNF-alpha, IL-6, and IL-10 after surgery were all significantly lower in the ultrafiltration group than in the control group (P<0.05) after the end of bypass. Blood propofol concentrations decreased significantly in both groups during cardiopulmonary bypass and remained significantly lower in the ultrafiltration group than the control group. However, there was no significant difference between the two groups in the entropy index (P=0.5583).

CONCLUSION

Low-volume zero-balanced ultrafiltration performed during cardiopulmonary bypass surgery significantly decreased post-bypass levels of the cytokines, TNF-alpha, IL-6, IL-10, and postoperative cardiac troponin I. Blood propofol concentration was also decreased; however, the depth of anesthesia was not affected significantly.

Single-center experience of 253 portal vein thrombosis patients undergoing liver transplantation in China

OBJECTIVE

We sought to review the etiopathogenesis, diagnosis, and surgical options for 253 patients with portal vein thrombosis (PVT) undergoing orthotopic liver transplantation (OLT) to assess the the impact of PVT on outcomes.

METHODS

We retrospectively analyzed the data from 2508 adult patients undergoing 2614 OLTs in our center from September 1998 to July 2007. PVT was scored according to the operative findings and Yerdel grading of PVT. No prisoners were used as donors for this study.

RESULTS

Two hundred fifty-three patients were diagnosed with PVT (10.09%): there were 104 grade I; 114, grade II; 29, grade III; and 6, grade IV PVT. Sex and previous splenectomy increased the risk for PVT. In grade I and II cases, we performed simple thrombectomy, eversion thrombectomy, or improved eversion thrombectomy (IET, innovated by our center), producing smooth postoperative recoveries with a 0% in-hospitality mortality. In grade III cases, 18 underwent successful IET. Of 11 subjects who had eversion thrombectomy, six failed, and the distal superior mesentery vein or dilated splanchnic collateral tributary had to be used as the inflow vessel in four patients, and portal vein arterialization were performed in the other two patients, all of whom experienced a smooth postoperative recovery except one who died of hepatic failure and pulmonary infection 2 weeks after the operation. The in-hospitality mortality was 3.45%. In grade IV cases, three underwent successful IET, but another three cases failed, with two of them requiring a renal vein as the inflow vessel, and other one undergoing portocaval hemitransposition, with one postoperative death due to hepatic failure and another of cancer recurrence, an in-hospitality mortality rate of 33.33%. The transfusion requirement among PVT patients was significantly higher than that in non-PVT patients (9.32 +/- 3.12 U vs 6.02 +/- 2.40 U; P < .01). Blood loss in PVT patients who underwent the IET technique was significantly lower than that for an eversion thrombectomy (2800.36 +/- 930.52 mL vs 5700.21 +/- 162.50 mL P < .05). The overall actuarial 1-year survival rate in PVT patients was similar to the controls (86.56% vs 89.40%; P > .05).

CONCLUSION

OLT was successfully performed for PVT patients. The grade of PVT decided the surgical strategy. Similar 1-year survival rates were attained between PVT patients and controls undergoing OLT.

Search for muon-neutrino to electron-neutrino transitions in MINOS

This Letter reports on a search for nu(mu) --> nu(e) transitions by the MINOS experiment based on a 3.14x10(20) protons-on-target exposure in the Fermilab NuMI beam. We observe 35 events in the Far Detector with a background of 27+/-5(stat)+/-2(syst) events predicted by the measurements in the Near Detector. If interpreted in terms of nu(mu) --> nu(e) oscillations, this 1.5sigma excess of events is consistent with sin2(2theta(13)) comparable to the CHOOZ limit when |Delta m2|=2.43x10(-3) eV2 and sin2(2theta(23))=1.0 are assumed.

A practical method for quantifying atherosclerotic lesions in rabbits

The rabbit has been widely used for the study of human atherosclerosis; however, the method for analysis of the atherosclerotic lesions has not been standardized between laboratories. The present study reports a practical method for quantifying the changes that occur in aortic atherosclerosis of rabbits. Male Japanese white rabbits were fed with either a standard chow or a diet containing 10% fat and 0.3% cholesterol for 16 weeks. Plasma concentrations of glucose, insulin, total cholesterol, triglycerides and high-density lipoprotein were measured. Aortic atherosclerotic lesions were assessed in quantitative fashion using an image analysis system that measured (1) the gross area of the entire aorta affected by atherosclerosis as defined by Sudan IV staining, (2) the microscopical intimal lesion defined by the elastic van Gieson stain and (3) the infiltration of macrophages and smooth muscle cell proliferation as determined immunohistochemically. The rabbits developed severe aortic atherosclerosis without apparent abnormality of glucose metabolism. The quantitative method described here will be useful for the further investigation of atherosclerosis in rabbits.

A review of the role of assistive technology for people with dementia in the hours of darkness

Assistive Technology (AT) has been utilized to support people with dementia (PwD) and their carers in the home. Such support can extend the time that PwD can remain safely at home and reduce the burden on the tertiary healthcare sector. Technology can assist people in the hours of darkness as well as during the day. The objective of this literature review is to evaluate reported healthcare technologies appropriate to night time care. This paper summarises and categorises the current evidence base. In all, 131 abstracts were returned from a database search, yielding fifty four relevant papers which were considered in detail. While night-time specific studies identified very few papers (4 papers, 7%), most of the more general AT findings could be adopted to benefit night-time assistance. Studies have used technology for prompting and reminding as loss of time and forgetfulness are major problems; for monitoring daily activities in a sensor enriched environment and utilised location aware technologies to provide information to enhance safety. Technology also supports a range of therapies to alleviate symptoms. Therapies include the delivery of music and familial pictures for reminiscing, the use of light therapy to enhance wellbeing and the provision of mental tasks to stimulate the brain and maintain activity levels.

Christmas: Years Like This. Ingested foreign bodies and societal wealth: three year observational study of swallowed coins

OBJECTIVE

To examine the relation between coins ingested by children and the Dow Jones Industrial Average.

DESIGN

Observational study. Main outcome measures Total value of coins ingested and number of incidents of coins versus other objects swallowed, measured before and after the stock market crash of October 2008.

RESULTS

Eighteen objects, including 11 coins, were ingested (NASDAQ (numismatic and sundry detritus acquired) composite of 18). The total value of the 11 coins swallowed was $1.03 (FTSE 100 (fraction of the US$ or 100 cents) index of 103). The pecuniary extraction ratio (PE ratio) was 0.57 (9/16). Comparing values for a period before and after October 2008, the mean monthly NASDAQ composite (0.41 (SD 0.67) v 0.5 (0.85), P=0.75), FTSE 100 index in cents (2.3 (6.8) v 3.1 (7.8), P=0.77), and PE ratio (0.54 (0.52) v 0.66 (0.29), P=0.50) did not change. The mean end-of-month closing value of the Dow Jones, however, decreased significantly (12 537 (841.4) v 8388 (699.8), P<0.001)

CONCLUSION

There was no detectable difference in the total value of coins ingested, or ratio of coins to other objects swallowed, before or after a massive stock market crash.

Thermoelectric effect across the metal-insulator domain walls in VO2 microbeams

We report on measurements of Seebeck effect in single-crystal VO(2) microbeams across their metal-insulator phase transition. One-dimensionally aligned metal-insulator domain walls were reversibly created and eliminated along single VO(2) beams by varying temperature, which allows for accurate extraction of the net contribution to the Seebeck effect from these domain walls. We observed significantly lower Seebeck coefficient in the metal-insulator coexisting regime than predicted by a linear combination of contributions from the insulator and metal domains. This indicates that the net contribution of the domain walls has an opposite sign from that of the insulator and metal phases separately. Possible origins that may be responsible for this unexpected effect were discussed in the context of complications in this correlated electron material.

Surface-stabilized nonferromagnetic ordering of a layered ferromagnetic manganite

An outstanding question regarding the probing or possible device applications of correlated electronic materials (CEMs) with layered structure is the extent to which their bulk and surface properties differ or not. The broken translational symmetry at the surface can lead to distinct functionality due to the charge, lattice, orbital, and spin coupling. Here we report on the case of bilayered manganites with hole doping levels corresponding to bulk ferromagnetic order. We find that, although the hole doping level is measured to be the same as in the bulk, the surface layer is not ferromagnetic. Further, our low-energy electron diffraction and x-ray measurements show that there is a c-axis collapse in the outermost layer. Bulk theoretical calculations reveal that, even at fixed doping level, the relaxation of the Jahn-Teller distortion at the surface is consistent with the stabilization of an A-type antiferromagnetic state.

Strain engineering and one-dimensional organization of metal-insulator domains in single-crystal vanadium dioxide beams

Correlated electron materials can undergo a variety of phase transitions, including superconductivity, the metal-insulator transition and colossal magnetoresistance. Moreover, multiple physical phases or domains with dimensions of nanometres to micrometres can coexist in these materials at temperatures where a pure phase is expected. Making use of the properties of correlated electron materials in device applications will require the ability to control domain structures and phase transitions in these materials. Lattice strain has been shown to cause the coexistence of metallic and insulating phases in the Mott insulator VO(2). Here, we show that we can nucleate and manipulate ordered arrays of metallic and insulating domains along single-crystal beams of VO(2) by continuously tuning the strain over a wide range of values. The Mott transition between a low-temperature insulating phase and a high-temperature metallic phase usually occurs at 341 K in VO(2), but the active control of strain allows us to reduce this transition temperature to room temperature. In addition to device applications, the ability to control the phase structure of VO(2) with strain could lead to a deeper understanding of the correlated electron materials in general.

Signature of checkerboard fluctuations in the phonon spectra of a possible polaronic metal La1.2Sr1.8Mn2O7

Charge carriers in low-doped semiconductors may distort the atomic lattice around them and through this interaction form so-called small polarons. High carrier concentrations on the other hand can lead to short-range ordered polarons (large polarons) and even to a long-range charge and orbital order. These ordered systems should be insulating with a large electrical resistivity. However, recently a polaronic pseudogap was found in a metallic phase of La(2-2x)Sr(1+2x)Mn(2)O(7) (ref. 7). This layered manganite is famous for colossal magnetoresistance associated with a phase transition from this low-temperature metallic phase to a high-temperature insulating phase. Broad charge-order peaks due to large polarons in the insulating phase disappear when La(2-2x)Sr(1+2x)Mn(2)O(7) becomes metallic. Investigating how polaronic features survive in the metallic phase, here we report the results of inelastic neutron scattering measurements showing that inside the metallic phase polarons remain as fluctuations that strongly broaden and soften certain phonons near the wavevectors where the charge-order peaks appeared in the insulating phase. Our findings imply that polaronic signatures in metals may generally come from a competing insulating charge-ordered phase. Our findings are highly relevant to cuprate superconductors with both a pseudogap and a similar phonon effect associated with a competing stripe order.

Site-activated multifunctional chelator with acetylcholinesterase and neuroprotective-neurorestorative moieties for Alzheimer's therapy

A novel strategy to develop site-activated multifunctional chelators for targeting multiple etiologies of Alzheimer's disease is reported. The novel prochelator HLA20A with improved cytotoxicity shows little affinity for metal ions until it is activated by binding and inhibiting acetylcholinesterase (AChE), releasing an active chelator HLA20 that modulates amyloid precursor protein (APP) regulation and beta-amyloid (Abeta) reduction, suppresses oxidative stress, and passivates excess metal ions (Fe, Cu, and Zn) in the brain.

Magnetic correlations in the extended kagome YBaCo4O7 probed by single-crystal neutron scattering

We have studied the frustrated system YBaCo4O7.0 generally described as an alternating stacking of kagome and triangular layers of magnetic ions on a trigonal lattice, by single-crystal neutron diffraction experiments above the Néel ordering transition. Experimental data reveal pronounced magnetic diffuse scattering, which is successfully modeled by direct Monte Carlo simulations. Long-range magnetic correlations are found along the c axis, due to the presence of corner-sharing bipyramids, creating quasi-one-dimensional order at finite temperature. In contrast, in the kagome layers (ab plane), the spin-spin correlation function, displaying a short-range 120 degrees configuration, decays rapidly as typically found in spin liquids. YBaCo4O7 experimentally realizes a new class of two-dimensional frustrated systems where the strong out-of-plane coupling does not lift the in-plane degeneracy, but instead acts as an external "field."

Gamow-Teller strength distributions in 48Sc by the 48Ca(p,n) and 48Ti(n,p) reactions and two-neutrino double-beta decay nuclear matrix elements

The double-differential cross sections for the 48Ca(p,n) and 48Ti(n,p) reactions were measured at 300 MeV. A multipole decomposition technique was applied to the spectra to extract the Gamow-Teller (GT) components. The integrated GT strengths up to an excitation energy of 30 MeV in 48Sc are 15.3+/-2.2 and 2.8+/-0.3 in the (p,n) and (n,p) spectra, respectively. In the (n,p) spectra additional GT strengths were found above 8 MeV where shell models within the fp shell-model space predict almost no GT strengths, suggesting that the present shell-model description of the nuclear matrix element of the two-neutrino double-beta decay is incomplete.