Comparison of High Fiber and Low Carbohydrate Diets on Owner-Perceived Satiety of Cats During Weight Loss

Food-seeking behaviors exhibited by cats during weight loss programs are frustrating to owners. Two categories of therapeutic weight loss diets are available for cats: High Fiber (HF) and Low Carbohydrate (LC). The objective of this study was to determine if cat owners perceive a difference in satiety when their cats are fed either a HF or LC diet during a weight loss regimen. Twenty-eight client-owned cats were randomly assigned to either an HF or LC canned diet and fed to 80% of their ideal weight resting energy requirements. Cats were rechecked at 2, 4, 6 and 8 weeks and food intake adjusted to maintain weight loss between 0.5-1% per week. Seventeen cats completed the 8-week weight loss study (HF = 10, LC = 7). Owners completed behavior questionnaires at each visit and were blinded to food assignments. The two diet groups did not differ significantly by age, sex, body condition score, caloric intake, or rate of weight loss during the study. The two diets did not differ by owner response to questionnaire. In conclusion, owners perceived cats to be equally satiated during weight loss regimens on both the HF and LC diets

Differential effects of dietary supplements on metabolomic profile of smokers versus non-smokers.

BackgroundCigarette smoking is well-known to associate with accelerated skin aging as well as cardiovascular disease and lung cancer, in large part due to oxidative stress. Because metabolites are downstream of genetic variation, as well as transcriptional changes and post-translational modifications of proteins, they are the most proximal reporters of disease states or reversal of disease states.MethodsIn this study, we explore the potential effects of commonly available oral supplements (containing antioxidants, vitamins and omega-3 fatty acids) on the metabolomes of smokers (n = 11) compared to non-smokers (n = 17). At baseline and after 12 weeks of supplementation, metabolomic analysis was performed on serum by liquid and gas chromatography with mass spectroscopy (LC-MS and GC-MS). Furthermore, clinical parameters of skin aging, including cutometry as assessed by three dermatologist raters blinded to subjects' age and smoking status, were measured.ResultsLong-chain fatty acids, including palmitate and oleate, decreased in smokers by 0.76-fold (P = 0.0045) and 0.72-fold (P = 0.0112), respectively. These changes were not observed in non-smokers. Furthermore, age and smoking status showed increased glow (P = 0.004) and a decrease in fine wrinkling (P = 0.038). Cutometry showed an increase in skin elasticity in smokers (P = 0.049) but not in non-smokers. Complexion analysis software (VISIA) revealed decreases in the number of ultraviolet spots (P = 0.031), and cutometry showed increased elasticity (P = 0.05) in smokers but not non-smokers.ConclusionsAdditional future work may shed light on the specific mechanisms by which long-chain fatty acids can lead to increased glow, improved elasticity measures and decreased fine wrinkling in smokers' skin. Our study provides a novel, medicine-focused application of available metabolomic technology to identify changes in sera of human subjects with oxidative stress, and suggests that oral supplementation (in particular, commonly available antioxidants, vitamins and omega-3 fatty acids) affects these individuals in a way that is unique (compared to non-smokers) on a broad level

Cardiovascular effects of fentanyl in conscious rats

Abstract.: The polymicrobial sepsis induced by cecal ligation and puncture (CLP) in the rat is widely used in shock research. For ethical reasons, narcotic analgesics are often administered in this model, with the potential risk of confounding effects. In conscious non-septic rats, we investigated the cardiovascular effects of a continuous i.v. infusion of fentanyl (20µg/kg per h) administered with fluid loading (10ml/kg per h) for 24h, a regimen commonly applied in rat CLP. Animals were randomly allocated to receive analgesia with fluid loading (Fentanyl group), or fluid loading alone (Control). All endpoints were assessed after 24h of infusion. At that time, Control animals had mild respiratory alkalosis, which was essentially abolished by fentanyl. Analgesia mildly elevated the plasma norepinephrine levels [median (interquartile range): Control 232pg/ml (0-292), Fentanyl 302pg/ml (234-676), P=0.045] but was devoid of any effect on blood pressure, heart rate, cardiac output (mean ±SD: Control 388±61ml/kg per min, Fentanyl 382±62ml/kg per min, P=0.87) and indices of left ventricular function derived from high-fidelity recordings of left ventricular pressure (dP/dt max: Control 11782±2324mmHg/s, Fentanyl 12107±2816mmHg/s, P=0.77). In ex vivo experiments carried out immediately after animal sacrifice, no differences were noted between the Control and Fentanyl groups in the sensitivity of endothelium-intact aortic rings to norepinephrine-induced vasoconstriction (-logEC50: Control 8.78±0.28, Fentanyl 8.83±0.26, P=0.52) or acetylcholine-induced vasodilatation (-logEC50: Control 7.00±0.37, Fentanyl 7.06±0.26±0.53, P=0.75). In conclusion, the present data provide no contraindication, and even some support for the ethical use of a high dose i.v. infusion of fentanyl in cardiovascular studies of conscious catheterized rats undergoing CLP or other painful procedure

Reversible Silencing of CFTR Chloride Channels by Glutathionylation

The cystic fibrosis transmembrane conductance regulator (CFTR) is a phosphorylation- and ATP-dependent chloride channel that modulates salt and water transport across lung and gut epithelia. The relationship between CFTR and oxidized forms of glutathione is of potential interest because reactive glutathione species are produced in inflamed epithelia where they may be modulators or substrates of CFTR. Here we show that CFTR channel activity in excised membrane patches is markedly inhibited by several oxidized forms of glutathione (i.e., GSSG, GSNO, and glutathione treated with diamide, a strong thiol oxidizer). Three lines of evidence indicate that the likely mechanism for this inhibitory effect is glutathionylation of a CFTR cysteine (i.e., formation of a mixed disulfide with glutathione): (a) channels could be protected from inhibition by pretreating the patch with NEM (a thiol alkylating agent) or by lowering the bath pH; (b) inhibited channels could be rescued by reducing agents (e.g., DTT) or by purified glutaredoxins (Grxs; thiol disulfide oxidoreductases) including a mutant Grx that specifically reduces mixed disulfides between glutathione and cysteines within proteins; and (c) reversible glutathionylation of CFTR polypeptides in microsomes could be detected biochemically under the same conditions. At the single channel level, the primary effect of reactive glutathione species was to markedly inhibit the opening rates of individual CFTR channels. CFTR channel inhibition was not obviously dependent on phosphorylation state but was markedly slowed when channels were first “locked open” by a poorly hydrolyzable ATP analogue (AMP-PNP). Consistent with the latter finding, we show that the major site of inhibition is cys-1344, a poorly conserved cysteine that lies proximal to the signature sequence in the second nucleotide binding domain (NBD2) of human CFTR. This region is predicted to participate in ATP-dependent channel opening and to be occluded in the nucleotide-bound state of the channel based on structural comparisons to related ATP binding cassette transporters. Our results demonstrate that human CFTR channels are reversibly inhibited by reactive glutathione species, and support an important role of the region proximal to the NBD2 signature sequence in ATP-dependent channel opening

Cryo-EM Structures of HIV-1 trimer bound to CD4-mimetics M48U1 and BNM-III-170 adopt a CD4-bound open conformation

Human Immunodeficiency Virus-1 (HIV-1), the causative agent of AIDS, impacts millions of people. Entry into target cells is mediated by the HIV-1 envelope (Env) glycoprotein interacting with host receptor CD4, which triggers conformational changes allowing binding to a coreceptor and subsequent membrane fusion. Small molecule or peptide CD4-mimetic drugs mimic CD4’s Phe43 interaction with Env by inserting into the conserved Phe43 pocket on Env subunit gp120. Here, we present single-particle cryo-EM structures of CD4-mimetics BNM-III-170 and M48U1 bound to a BG505 native-like Env trimer plus the CD4-induced antibody 17b at 3.7Å and 3.9Å resolution, respectively. CD4-mimetic-bound BG505 exhibits canonical CD4-induced conformational changes including trimer opening, formation of the 4-stranded gp120 bridging sheet, displacement of the V1V2 loop, and formation of a compact and elongated gp41 HR1C helical bundle. We conclude that CD4-induced structural changes on both gp120 and gp41 Env subunits are induced by binding to the gp120 Phe43 pocket

Plasma Membrane Insertion of KCa2.3 (SK3) is Dependent Upon the SNARE Proteins, Syntaxin-4 and SNAP23

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. We previously demonstrated endocytosis of KCa2.3 is caveolin-1-, dynamin II- and Rab5-dependent. KCa2.3 then enters Rab35/EPI64C- and RME-1-containing recycling endosomes and is returned to the plasma membrane (PM). Herein, we report on the mechanism by which KCa2.3 is inserted into the PM during recycling and following exit from the Golgi. We demonstrate KCa2.3 colocalizes with SNAP-23 and Syntaxin-4 in the PM of HEK and endothelial cells by confocal immunofluorescence microscopy. We further show KCa2.3 can be co-immunoprecipitated with SNAP-23 and Syntaxin-4. Overexpression of either Syntaxin-4 or SNAP-23 increased PM expression of KCa2.3, whereas shRNA-mediated knockdown of these SNARE proteins significantly decreased PM KCa2.3 expression, as assessed by cell surface biotinylation. Whole-cell patch clamp studies confirmed knockdown of SNAP-23 significantly decreased the apamin sensitive, KCa2.3 current. Using standard biotinylation/stripping methods, we demonstrate shRNA mediated knockdown of SNAP-23 inhibits recycling of KCa2.3 following endocytosis, whereas scrambled shRNA had no effect. Finally, using biotin ligase acceptor peptide (BLAP)-tagged KCa2.3, coupled with ER-resident biotin ligase (BirA), channels could be biotinylated in the ER after which we evaluated their rate of insertion into the PM following Golgi exit. We demonstrate knockdown of SNAP-23 significantly slows the rate of Golgi to PM delivery of KCa2.3. The inhibition of both recycling and PM delivery of newly synthesized KCa2.3 channels likely accounts for the decreased PM expression observed following knockdown of these SNARE proteins. In total, our results suggest insertion of KCa2.3 into the PM depends upon the SNARE proteins, Syntaxin-4 and SNAP-23