bluuebunny/crossref_metadata_2025 huggingface dataset:
Resistance training-induced decrease in central arterial compliance is associated with decreased subendocardial viability ratio in healthy young men
Authors: Tagawa Kaname , Choi Youngju , Ra Song-Gyu , Yoshikawa Toru , Kumagai Hiroshi , Maeda Seiji
Published: December 2017

High-intensity resistance training decreases central arterial compliance (CAC). Subendocardial viability ratio (SEVR) is a useful tool that reflects the balance between coronary perfusion and left ventricular afterload. Animal studies have demonstrated that decreased CAC is associated with SEVR deterioration. Therefore, resistance training-induced decrease in CAC may be associated with changes in SEVR. The objective of the present study was to investigate the association between SEVR and CAC using both cross-sectional and longitudinal (i.e., resistance training) study designs. To achieve this, we first conducted a cross-sectional study to investigate the association between SEVR and CAC in 89 young men. Thereafter, a longitudinal study was performed to examine the effects of resistance training on SEVR and CAC in young men. A total of 28 young men were divided into 2 groups: control (n = 13) and training (n = 15). In the training group, subjects underwent supervised resistance training for 4 weeks (5 sets of 10 repetitions at 75% of 1-repetition maximum, 3 times/week). CAC and SEVR were then measured in all subjects. In the cross-sectional study, SEVR was significantly positively correlated with CAC, whereas resistance training significantly decreased both SEVR and CAC. Moreover, training-induced changes in CAC were significantly correlated with changes in SEVR. Thus, these results suggest that resistance training-induced decrease in CAC is associated with decreased SEVR in young men.
Short time effect of a single session of intense whole-body electromyostimulation on energy expenditure. A contribution to fat reduction?
Authors: Teschler Marc , Wassermann Alfred , Weissenfels Anja , Fröhlich Michael , Kohl Matthias , Bebenek Michael , von Stengel Simon , Kemmler Wolfgang
Published: December 2017

To determine the underlying mechanisms after 1 session of (intense) whole-body electromyostimulation (WB-EMS) on total energy expenditure (TEE) and resting metabolic rate (RMR), 16 subjects followed a standardized protocol of indirect calorimetry for up to 72 h in 12-h intervals. The single session significantly increased RMR by approximately 25% ± 10% (p < 0.001) and TEE by approximately 9.5% ± 1%, a net effect of ∼460 ± 50 kcal (WB-EMS vs. control group).
A divergent synthesis to generate targeted libraries of inhibitors for endo-N-acetylglucosaminidases
Authors: Seo Isaac K. , Woo Esther H. , Cecioni Samy , Vocadlo David J.
Published: December 2017

Cell active inhibitors of glycoside processing enzymes are valuable research tools that help us understand the physiological roles of this diverse class of enzymes. endo-N-Acetylglucosaminidases have gained increased attention for their important roles in both mammals and human pathogens; however, metabolically stable cell active inhibitors of these enzymes are lacking. Here, we describe a divergent synthetic strategy involving elaboration of a thiazoline core scaffold. We illustrate the potential of this approach by using the copper catalysed azide-alkyne click (CuAAC) reaction, in combination with a suitable catalyst to avoid poisoning by the thiazoline moiety, to generate a targeted panel of candidate inhibitors of endo-N-acetylglucosaminidases and chitinases.
Molecular structure and melting: implications for phase change materials
Authors: Noël John A. , Kahwaji Samer , White Mary Anne
Published: December 2017

Phase change materials (PCMs) offer a promising technology for thermal energy storage, load leveling, and peak shifting applications. A desirable PCM has a melting temperature within the temperature boundaries of its application and a high change in enthalpy on melting. Knowledge of the relationships between these thermodynamic properties and molecular structure would advance informed selection of PCM candidates for a given application. In the present investigation, the relationship between structure (length of alkyl chains) and melting properties has been investigated for isomeric esters, showing that esters containing longer individual alkyl chains have higher melting temperatures and higher enthalpy changes on melting. The melting entropy changes, however, are relatively independent of the alkyl chain distribution.
Sampling the stream landscape: improving the applicability of an ecoregion-level capture probability model for stream fishes
Authors: Mollenhauer Robert , Mouser Joshua B. , Brewer Shannon K.
Published: December 2017

Temporal and spatial variability in streams result in heterogeneous gear capture probability (i.e., the proportion of available individuals identified) that confounds interpretation of data used to monitor fish abundance. We modeled tow-barge electrofishing capture probability at multiple spatial scales for nine Ozark Highland stream fishes. In addition to fish size, we identified seven reach-scale environmental characteristics associated with variable capture probability: stream discharge, water depth, conductivity, water clarity, emergent vegetation, wetted width–depth ratio, and proportion of riffle habitat. The magnitude of the relationship between capture probability and both discharge and depth varied among stream fishes. We also identified lithological characteristics among stream segments as a coarse-scale source of variable capture probability. The resulting capture probability model can be used to adjust catch data and derive reach-scale absolute abundance estimates across a wide range of sampling conditions with similar effort as used in more traditional fisheries surveys (i.e., catch per unit effort). Adjusting catch data based on variable capture probability improves the comparability of data sets, thus promoting both well-informed conservation and management decisions and advances in stream-fish ecology.
Foot-and-mouth disease virus infection stimulates innate immune signaling in the mouse macrophage RAW 264.7 cells
Authors: Zhi Xiaoying , Lv Jianliang , Wei Yanquan , Du Ping , Chang Yanyan , Zhang Yun , Gao Yuan , Wu Run
Published: December 2017

The innate immune system acts as the first line of defense against invasion by bacterial and viral pathogens. The role of macrophages in innate immune responses to foot-and-mouth disease virus (FMDV) is poorly understood. To determine the mechanism underlying activation of innate immunity after FMDV infection in macrophages, we performed FMDV infection in mouse macrophage RAW 264.7 cells and found that FMDV serotype O infection induced a cytopathic effect. We then evaluated the gene expression profile in macrophage RAW 264.7 cells after FMDV infection using systematic microarray analysis. Gene ontology annotation and enrichment analysis revealed that FMDV promoted expression in a group of genes that are enriched in innate immune response and inflammatory response processes. Further research demonstrated that FMDV serotype O infection enhanced NF-κB, Toll-like, and RIG-I-like receptor signaling pathways and proteins expression and increased transcription and expression of a series of cytokines and interferons, as proved by qRT-PCR, Western blot, ELISA, and dual-luciferase reporter assay. Our study concluded that FMDV infection triggers the innate immune response in macrophages after activation of multiple innate immune pathway receptors and proteins by FMDV serotype O, resulting in activation and secretion of a series of cytokines and interferons.
Entropic uncertainty relation under correlated dephasing channels
Authors: Karpat Göktuğ
Published: December 2017

Uncertainty relations are a characteristic trait of quantum mechanics. Even though the traditional uncertainty relations are expressed in terms of the standard deviation of two observables, there exists another class of such relations based on entropic measures. Here we investigate the memory-assisted entropic uncertainty relation in an open quantum system scenario. We study the dynamics of the entropic uncertainty and its lower bound, related to two incompatible observables, when the system is affected by noise, which can be described by a correlated Pauli channel. In particular, we demonstrate how the entropic uncertainty for these two incompatible observables can be reduced as the correlations in the quantum channel grow stronger.
Relationship between negative differential thermal resistance and asymmetry segment size
Authors: Kong Peng , Hu Tao , Hu Ke , Jiang Zhenhua , Tang Yi
Published: December 2017

Negative differential thermal resistance (NDTR) was investigated in a system consisting of two dissimilar anharmonic lattices exemplified by Frenkel–Kontorova (FK) lattices and Fremi–Pasta–Ulam (FPU) lattices (FK-FPU). The previous theoretical and numerical simulations show the dependence of NDTR are the coupling constant, interface and system size, but we find the segment size also to be an important element. It’s interesting that NDTR region depends on FK segment size rather than FPU segment size in this coupling FK-FPU model. Remarkably, we could observe that NDTR appears in the strong interface coupling strength case which is not NDTR in previous studies. The results are conducive to further developments in designing and fabricating thermal devices.
Physical and optical properties of calcium sulfate ultra-phosphate glass-doped Er2O3
Authors: Aliyu Aliyu Mohammed , Hussin R. , Deraman Karim , Ahmad N. E. , Danmadami Amina M. , Yamusa Y. A.
Published: December 2017

The influence of erbium on physical and optical properties of calcium sulfate ultra-phosphate glass was investigated using conventional melt quench process. Selected samples of composition 20CaSO4 (80 – x) P2O5– xEr2O3 with 0.1 [Formula: see text]x [Formula: see text] 0.9 mol.% were prepared and assessed. X-ray diffraction (XRD) techniques were used to confirm the amorphous nature of the said samples. The structural units of phosphate-based glass were assessed from Raman spectra as ultra-(Q3), meta-(Q2), pyro-(Q1) and orthophosphate (Q0) units. Depolymerization process of the glasses was testified for higher calcium oxide content and UV-visible for optical measurement. Thermal analysis have been investigated by means of thermogravimetric analysis. The results show the decomposition of materials in the temperature range of 25[Formula: see text]C–1000[Formula: see text]C. Er[Formula: see text] absorption spectra were measured in the range of 400–1800[Formula: see text]nm. PL measurement was carried out in order to obtain the excitation and emission spectra of the samples. The emission spectra excited at 779[Formula: see text]nm comprises of 518[Formula: see text]nm, 550[Formula: see text]nm and 649[Formula: see text]nm of transition 4F[Formula: see text], 4S[Formula: see text] and 2H[Formula: see text] excited states to 4I[Formula: see text] ground state. In physical properties, the density calculated using Archimedes method is inversely proportional to molar volume with increase in Er[Formula: see text] ions. Optical bandgap (E[Formula: see text]) were determined using Tauc’s plots for direct transitions where E[Formula: see text] (direct) decreases with increase in erbium content. The refractive index increases with decreasing molar volume; this may have a tendency for larger optical bandgap. The result obtained from the glass matrix indicates that erbium oxide-doped calcium sulfate ultra-phosphate may give important information for wider development of functional glasses.
Review on Automatic Lip Reading Techniques
Authors: Lu Yuanyao , Yan Jie , Gu Ke
Published: December 2017

As a significant component of the Human Computer Interface (HCI), automatic lip reading is designed for the purpose of understanding the content of speech by interpreting the movements of the lips. Although performance of automatic lip reading system is easily affected by challenging conditions such as noise, illumination and low resolution, enormous advancements in the relevant fields accompanied with enhancement in computer capability have improved the robustness of the system, making it more adaptable to the real environment. In this paper, we study the field and gives a detailed discussion on the actuality and the developing level of automatic lip reading. We emphatically introduce the feature extraction and recognition model algorithms. We also compare and analyze the various visual speech databases for their characteristics and functions in speech recognition systems. In addition, we describe the challenges and offer our insights into future research direction of automatic lip reading.
Characterization of signed Gauss paragraphs and skew-symmetric graded matrices
Authors: Rodríguez-Nieto José Gregorio
Published: December 2017

In this paper, we use theory of embedded graphs on oriented and compact [Formula: see text]-surfaces to construct minimal realizations of signed Gauss paragraphs. We prove that the genus of the ambient surface of these minimal realizations can be seen as a function of the maximum number of Carter’s circles. For the case of signed Gauss words, we use a generating set of [Formula: see text], given in [G. Cairns and D. Elton, The Planarity problem for signed Gauss world, J. Knots Theor. Ramif. 2(4) (1993) 359–367], and the intersection pairing of immersed [Formula: see text]-normal curves to present a short solution of the signed Gauss word problem. We relate this solution with the one given by Cairns and Elton. Moreover, we define the join operation on signed Gauss paragraphs to produce signed Gauss words such that both can be realized on the same minimal genus [Formula: see text]-surface.

We connect the characterization of signed Gauss paragraph with the recognition virtual links problem. Also we present a combinatorial algorithm to compute, in an easier way, skew-symmetric graded matrices [V. Turaev, Cobordism of knots on surfaces, J. Topol. 1(2) (2008) 285–305] for virtual knots through the concept of triplets [M. Toro and J. Rodríguez, Triplets associated to virtual knot diagrams, Rev. Integración (2011)]. Therefore, we can prove that the Kishino’s knot is not classical, moreover, we prove that the virtual knots of the family [Formula: see text] given in [H. A. Dye, Virtual knots undetected by [Formula: see text] and [Formula: see text]-strand bracket polynomials, Topol. Appl. 153 (2005) 141–160] are not classical knots.
Phase-sensitive Kerr nonlinearity of V-type atoms-doped dielectric slab
Authors: Younessi B. , Sahrai M. , Aghbulaghi R. , Poursamad J. B.
Published: December 2017

We investigate the linear and nonlinear dispersion and absorption properties of a weak probe field in a slab doped with V-type atoms. The effect of relative phase between applied fields on linear and nonlinear dispersion and absorption is discussed. It is demonstrated that the system is phase-sensitive when spontaneously generated coherence (SGC) exists. The effects of coupling field intensity, incoherent pump, and phase difference between probe and coupling fields on Kerr nonlinearity are also presented.
Games with Symmetric Incomplete Information and Asymmetric Computational Resources
Authors: Gavrilovich Misha , Kreps Victoria
Published: December 2017

We consider random public signals on the state of two-person zero-sum game with incomplete information on both sides (both players do not know the state of the game). To learn the state, each player chooses a finite automaton which receives the public signal; the player only sees the output of the automaton chosen. Supposing that the size of automata available to Player 1 is essentially bigger than that available to Player 2, we give an example of public signal with random length of output strings where the posterior belief of Player 1 is the state and the posterior belief of Player 2 is close to his original belief. Thus, we demonstrate that asymmetric information about the state of a game may appear not only due to a private signal but as a result of a public signal and asymmetric computational resources of players.

Besides, for a class of random signals with fixed length of output strings, we estimate the fraction of signals such that some automaton of given size may help Player 2 to significantly reestimate prior probability of the state. We show that this fraction is negligible if the size of automata of Player 2 is sufficiently smaller than length of output strings.
Minimum distance functions of complete intersections
Authors: Martínez-Bernal José , Pitones Yuriko , Villarreal Rafael H.
Published: December 2017

We study the minimum distance function of a complete intersection graded ideal in a polynomial ring with coefficients in a field. For graded ideals of dimension one, whose initial ideal is a complete intersection, we use the footprint function to give a sharp lower bound for the minimum distance function. Then we show some applications to coding theory.
Embedding the set of nondivisorial ideals of a numerical semigroup into ℕn
Authors: Spirito Dario
Published: December 2017

The set [Formula: see text] of the classes of nondivisorial ideals of a numerical semigroup [Formula: see text] can be endowed with a natural partial order induced by the set of star operations on [Formula: see text]. We study embeddings of [Formula: see text] into [Formula: see text], specializing on three families of numerical semigroups with radically different behavior.
Support varieties of baby Verma modules
Authors: Li Yiyang , Shu Bin , Yao Yufeng
Published: December 2017

Let [Formula: see text] be a connected reductive algebraic group over an algebraically closed field [Formula: see text] of prime characteristic [Formula: see text] and [Formula: see text]. For a given nilpotent [Formula: see text]-character [Formula: see text], let [Formula: see text] be a baby Verma module associated with a restricted weight [Formula: see text]. A conjecture describing the support variety of [Formula: see text] via that of its restricted counterpart is given: [Formula: see text]. Under the assumption of [Formula: see text](the Coxeter number) and [Formula: see text] [Formula: see text]-regular, this conjecture is proved when [Formula: see text] falls in the regular nilpotent orbit for any [Formula: see text] and the subregular nilpotent orbit for [Formula: see text] being of type [Formula: see text]. We also verify this conjecture whenever [Formula: see text] is of type [Formula: see text] and [Formula: see text] falls in the minimal nilpotent orbit.
Filter regular sequences and endomorphisms of local cohomology modules
Authors: Zangoiezadeh Ebrahim , Khashyarmanesh Kazem
Published: December 2017

Let [Formula: see text] be a commutative Noetherian ring and [Formula: see text] be an ideal of [Formula: see text] such that [Formula: see text], where [Formula: see text] is the cohomological dimension of [Formula: see text] with respect to [Formula: see text] and [Formula: see text] is the grade of [Formula: see text]. We show that whenever, [Formula: see text] for all [Formula: see text] and all integers [Formula: see text] with [Formula: see text] and [Formula: see text], then there exists an exact sequence [Formula: see text] of endomorphisms of local cohomology modules, where [Formula: see text] and, for [Formula: see text], [Formula: see text] is the ring of fractions of [Formula: see text] with respect to multiplicatively closed subset [Formula: see text] of [Formula: see text].
Regular sequences and vanishing of the homological functors
Authors: Bahmanpour Kamal
Published: December 2017

Let [Formula: see text] be a Noetherian local ring of dimension [Formula: see text] and let [Formula: see text] be a nonzero finitely generated [Formula: see text]-module. Let [Formula: see text] be a positive integer and let [Formula: see text] be an [Formula: see text]-regular sequence. In this paper we shall present some equivalent conditions for the vanishing of the [Formula: see text]-modules [Formula: see text] and [Formula: see text].
Investigations on Photocatalytic, Antimicrobial and Magnetic Properties of Sol–Gel-Synthesized Ga-Doped ZnO Nanoparticles
Authors: Malhotra Jaskaran Singh , Sharma Arnav , Singh Arun Kumar , Kumar Sanjeev , Rana Bhupendra Singh , Kumar Sanjeev
Published: December 2017

Gallium (Ga)-doped zinc oxide (ZnO) nanoparticles were synthesized using simple and cost-effective sol–gel method. X-ray powder diffraction studies illustrated the crystalline nature of Ga-doped ZnO nanoparticles with hexagonal wurtzite structure. Fourier-transform infrared spectroscopy and energy dispersive X-ray fluorescence confirmed the Ga[Formula: see text] incorporation in ZnO. The photocatalytic activities of all the synthesized samples were performed on methylene blue dye solution exposed under UV light. The antibacterial activities of the synthesized nanoparticles were investigated against Aeromonas liquefaciens and Shigella flexeneri gram-negative pathogenic strains. The experimental results clearly demonstrated significant enhancement in photocatalytic and antimicrobial activity of ZnO nanoparticles doped with optimum concentration of Ga. Room temperature vibrating sample magnetometer measurements illustrated weak ferromagnetism in all the Ga-doped ZnO samples.
Some crystallographic Haar type composite dilation wavelets for P4 = C4 ⋉ ℤ2
Authors: Deshpande R. , Bhate H.
Published: December 2017

Composite dilation wavelets generate bases or frames using two groups of dilations. One group is associated with a set [Formula: see text] where [Formula: see text] is an expanding matrix with [Formula: see text] an integer. The second group is associated with the subgroup [Formula: see text] of matrices [Formula: see text] with [Formula: see text] Here, we present crystallographic Haar type composite dilation wavelets generated by such two dilation groups associated with [Formula: see text] Further, we provide matricial filters and reconstruction formulae at various scales.
Impacts Assessments without True Baselines: Assessing the Relative Effects of Training on the Performance of Water User Associations in Southern Tajikistan
Authors: Balasubramanya Soumya , Price Joseph P. G. , Horbulyk Theodore M.
Published: December 2017

Conducting rigorous evaluations of whether the process of creating new institutions affects their performance of mandated duties presents several challenges. Not only is assignment to process often not random, but when the process of creating new institutions starts, outcomes and other performance-influencing covariates are not measurable because the yet-to-be created institutions are not functioning at baseline. This paper compares the performance of 74 ‘treated’ water user associations (WUAs) in Tajikistan that were created using a longer training process with 67 ‘control’ WUAs that were created using shorter training, to assess the impact of training on WUA performance of mandated duties. First, propensity scores were constructed to estimate the probabilities of being ‘treated’ by treatment status. These results guided the application of the difference-in-difference technique with right-hand side covariates in a context where field measures of outcomes and other performance-influencing covariates were made after the new institutions were created and functioning. The first measures were taken within 12–18 months of the new institutions being functional and the second measures were taken 24 months after the first. This choice of methods introduces a bias due to measurement error causing an underestimate of the treatment effects, while controlling for biases due to time-invariant and time-varying unobservables. An alternative method that only compared the differences in outcomes at a single point in time after the new institutions were created would have provided an inaccurate estimate of the effects of the intervention. This is a context in which methods such as synthetic controls are impossible to employ due to the nature of the intervention, other macroeconomic structural changes, and severe data restrictions. The methodology employed here generates evidence that, while biased toward generating an underestimate of effect, can still be useful and informative for policy and management purposes, and for evaluating the impact of process on the functioning of new institutions in transition settings.
Plasma concentrations of total and free corticosterone during development in the rat.
Authors: Henning S J
Published: December 2017

A sensitive protein-binding assay has been used to measure plasma concentrations of total corticosterone during postnatal development in the rat. These concentrations were extremely low on days 6--12, showed a significant rise by day 14, and then continued to rise until peaking on day 24. Plasma titers of corticosteroid-binding globulin rose even more dramatically from day 12 onward. Consequently, the percentage of total plasma corticosterone, which was protein-bound, showed a gradual rise from 78% on day 12 to 98% on day 24. Despite this trend, when concentrations of free corticosterone were calculated, they were found to have a developmental profile very similar to that of total corticosterone. Assay of jejunal lactase and sucrase in the same animals that were used for the corticosterone studies showed that the ontogenic rise of both total and free corticosterone preceded the developmental changes in the activities of these enzymes by approximately 2 days. The data suggest that the rise in free corticosterone that begins on day 14 acts as a cue for enzymic changes in both liver and intestine.
Hyperpolarization as a mediator of insulin action: increased muscle glucose uptake induced electrically
Authors: Zierler K. , Rogus E. M.
Published: December 2017

Insulin hyperpolarizes. This raises the questions: is hyperpolarization a means by which insulin exerts some of its other effects, and can electrically induced hyperpolarization mimic insulin action on membrane functions? A technique was devised to study the latter question. The technique permits electrical hyperpolarization of a segment of whole muscle. Rat caudofemoralis muscle was threaded into a triple sucrose-gap chamber. Continuous flow of sucrose displaced interstitial fluid of muscle segments in the gaps. In one electrolyte compartment between gaps was placed an anode and in the other a cathode. The muscle segment in the anodal compartment was hyperpolarized continuously for 30 min, probably by about 1.5 mV. Uptake of deoxyglucose was increased in the hyperpolarized muscle segment. This increase, by 39%, was highly significant. It was probably smaller than the twofold increase elicited by insulin (100 mU/ml), but not than the possible effect produced by 10 mU/ml. The effect of hyperpolarization was specific for the D-glucose transport system because uptake of L-glucose was not altered.
Interorgan relationships for glutamine metabolism in normal and acidotic rats
Authors: Schrock H. , Goldstein L.
Published: December 2017

The interorgan relationships for glutamine were investigated in normal, chronically acidotic, and diabetic ketoacidotic rats. In the normal rat, muscle tissue is the major site that releases glutamine into the circulation, and the nonhepatic splanchnic bed (mainly gut) is the major site of glutamine uptake. The liver of normal, postabsorptive rats takes up glutamine also. The kidneys have no significant affect on circulating glutamine in normal rats. In chronic NH4Cl and HCl acidosis, muscle glutamine release doubles. In addition, the liver decreases glutamine uptake and releases glutamine into the circulation. Muscle and liver supply, respectively, about 55 and 45% of the increased glutamine demand of the kidneys during chronic acidosis. No significant changes could be detected in the nonhepatic splanchnic bed during acidosis. In diabetic ketoacidotic rats, the increased demand for glutamine by the kidneys is almost entirely supplied by muscle. No significant changes occur in liver or nonhepatic splanchnic bed.
Theophylline-estrogen interaction in the rat uterus: role of the ovary
Authors: Steinsapir J. , Rojas A. M. , Tchernitchin A.
Published: December 2017

Uterine edema induced by 0.1 microgram/100 g body wt of estradiol further increases in the presence of theophylline. Theophylline alone or in the presence of 0.001, 0.01, 0.1, and 1 microgram/100 g body wt of estradiol increases uterine RNA and protein content 6 h after its administration, as compared with the same doses of estradiol alone. Both phenomena disappear in the ovariectomized immature rat, suggesting that theophylline potentiates the action of gonadotropins, increasing the synthesis of endogenous ovarian estrogens by the immature ovary. Theophylline decreases the number of eosinophils in the blood and concurrently decreases estrogen-induced uterine eosinophilia at doses of 0.01, 0.1, 1, 10, and 30 micrograms/100 g body wt of estradiol. Estrogen binding by uterine eosinophils in vitro increases in the presence of theophylline. This effect of theophylline could also explain the increase in vivo in estrogen-induced uterine edema.
Muscle mitochondrial bioenergetics, oxygen supply, and work capacity during dietary iron deficiency and repletion
Authors: Davies K. J. , Maguire J. J. , Brooks G. A. , Dallman P. R. , Packer L.
Published: December 2017

Relationships between muscle oxidative capacity, anemia, endurance, whole-body maximal O2 consumption (VO2 max), and VO2 max work load (maximal treadmill speed at 15% grade, rat weight constant) were investigated in iron deficiency and during dietary iron repletion. Young rats were made severely iron deficient by a diet containing 2 mg iron/kg. Control animals received the same diet but with 50 mg iron/kg. Blood hemoglobin was decreased to 3.6 +/- 0.5 g/dl compared to 13.7 +/- 0.6 in control animals. The combination of decreased mitochondrial enzyme specific activities and a 30% reduction in the mitochondrial content of muscle resulted in 60-85% decreases in muscle oxidative capacities. VO2 max and VO2 max work load were both 50% lower in deficient rats, whereas endurance capacity was 90% lower in deficient animals than controls. The iron sufficient control diet was then given to deficient rats and the course of dietary repletion followed. Hemoglobin increased substantially within 3 days in parallel with VO2 max and VO2 max work load. No significant improvements in mitochondrial bioenergetic functions, mitochondrial content of muscle, muscle oxidative capacity, or endurance capacity occurred until the 5th day. We conclude that VO2 max and VO2 max work load capacity were not limited by muscle oxidative capacity. Conversely, endurance capacity was not restricted by oxygen supply, but was primarily determined by the oxidative capacity of muscle.
Nutrient-induced intracellular calcium movement in rat pancreatic B cell
Authors: Lebrun P. , Malaisse W. J. , Herchuelz A.
Published: December 2017

Several insulin secretagogues increase 45Ca efflux from islets prelabeled with the tracer in the presence of glucose, an effect attributable to stimulation of 40Ca entry into islet cells. When the islets are prelabeled in the absence instead of presence of glucose, the 45Ca becomes more readily releasable, and the secretory response to nutrient or ionic secretagogues is decreased. Such a decrease is more marked in response to glucose than other secretagogues because the prior nutrient deprivation also impairs the metabolism of glucose in islet cells. In the islets prelabeled in the absence of glucose, both glyceraldehyde and 2-ketoisocaprote dramatically stimulated 45Ca efflux. This effect persists in the absence of extracellular Ca2+ or presence of the calmodulin-antagonist trifluoperazine. It may correspond to a nutrient-induced intracellular Ca2+ movement, the existence of which would be unmasked in islets prelabeled in the absence of glucose. This so-far-undetected Ca2+ movement may play a role in the secretory response to nutrient secretagogues.
Brown adipose tissue of rats with obesity-inducing ventromedial hypothalamic lesions
Authors: Hogan S. , Coscina D. V. , Himms-Hagen J.
Published: December 2017

Male and female Holtzman rats were made hyperphagic and obese with bilateral radiofrequency heat lesions of the ventromedial hypothalamic (VMH) area. When VMH rats were maintained at 28 degrees C, their brown adipose tissue (BAT) DNA, protein, and cytochrome oxidase contents were normal although more stored lipid was present, as judged from a threefold increase in wet weight. Thermogenic activity of BAT mitochondria was normal in male VMH rats, as judged from the unchanged level of guanosine diphosphate (GDP) binding (known to be a sensitive index of the functional activity of the thermogenic proton conductance pathway), and reduced in female VMH rats. When rats with VMH lesions were exposed to cold (4 degrees C for 24 h), the visible hyperemia of their BAT and normal large increase in mitochondrial GDP binding indicated normal thermogenic responsiveness. We conclude that the medial nuclei of the hypothalamus and associated afferent or efferent nerve tracts do not represent an essential central nervous system link for cold-induced, sympathetic-mediated activation of BAT thermogenesis. It is possible, however, that diet-induced, sympathetic-mediated activation of BAT function and growth might require an intact VMH region because no enhancement of BAT mitochondrial function normally associated with hyperphagia was detected in these hyperphagic VMH-lesioned animals.
Steroidogenesis by avian ovarian cells: effects of luteinizing hormone and substrate availability
Authors: Marrone B. L. , Hertelendy F.
Published: December 2017

The production of progesterone (P) and estrogen (E) by enzymatically dispersed granulosa and theca cells from chicken preovulatory follicles was examined in 3-h incubations. Accumulation of the P produced by granulosa cells was significantly reduced by the addition of theca cells, whereas E production was increased. The decrease in P accumulation was shown to be due to extensive metabolism of P by theca cells. There were no synergistic effects of luteinizing hormone (LH) and any substrate tested on E production by theca cells. Maturation of granulosa cells was characterized by an increased sensitivity to LH stimulation of P production, but there was no change in pregnenolone conversion to P. Conversely, maturation of theca cells was accompanied by decreased in both sensitivity to LH and the ability to convert substrates to E. The results are discussed in terms of the contribution of each cell type in the production of steroids by chicken follicles during maturation.
Effects of food deprivation and refeeding on total protein and actomyosin degradation
Authors: Li J. B. , Wassner S. J.
Published: December 2017

Total protein and actomyosin degradation rates were determined in perfused rat hemicorpus preparations. By simultaneously measuring the release of two nonmetabolizable amino acids phenylalanine and N tau-methylhistidine from the hemicorpus, the respective rates of total protein and actomyosin degradation could be calculated. When rats were deprived of food for 48 h, the rate of total protein degradation increased to 148% of the fed controls. If rats were food deprived and then refed for 24 h, the degradation rate decreased to only 79% of the rate of fed controls. Measurement of N tau-methylhistidine release indicated that food deprivation led to a dramatic increase in the rate of actomyosin degradation (427% of fed), whereas refeeding decreased the actomyosin degradation rate to that of the fed controls. Calculations of the fractional degradation rates show that actomyosin breaks down at a much slower rate than the nonactomyosin proteins (1.5 vs. 20.8%/day in preparations from fed rats, and 6.2 vs. 28.2%/day in preparations from food-deprived rats). Therefore, the contribution of actomyosin breakdown to total muscle protein breakdown is small in the fed state (11%) and increased threefold after food deprivation. The addition of insulin to the perfusion medium decreased the rate of total protein degradation by 18% in preparations from food-deprived rats with no significant effect on actomyosin degradation. Thus, in vitro, insulin's major effect may be to decrease the degradation of more rapidly turning over, nonactomyosin proteins. Protein degradation, as well as protein synthesis, contributes to the adaptation of muscle to starvation and refeeding.(ABSTRACT TRUNCATED AT 250 WORDS)
Influence of exercise on urea, creatinine, and 3-methylhistidine excretion in normal human subjects
Authors: Calles-Escandon J. , Cunningham J. J. , Snyder P. , Jacob R. , Huszar G. , Loke J. , Felig P.
Published: December 2017

To evaluate the effects of exercise on net protein catabolism, the losses of urea in sweat and urine and urinary creatinine and 3-methylhistidine (3MH) excretion were determined in eight healthy subjects during cycle ergometer exercise performed at approximately 45% of VO2max for 90 min. The subjects ingested a meat-free diet for 5 days starting 3 days before and continuing for 1 day after the day of exercise. During exercise, total urea excretion (urine + sweat losses) increased 100% above pre- and postexercise values. Thirty percent of the total urea excretion during exercise was in the form of sweat losses. Total protein breakdown (as reflected by urea excretion), however, could account for less than 5% (21 +/- 4 kcal) of total calorie expenditure during the exercise (567 +/- 83 kcal). Urinary creatinine excretion increased by 50% during exercise. Urinary excretion of 3MH also tended to rise, but the ratio of urinary 3MH to creatinine showed no change in response to exercise. We conclude that 1) light to moderate exercise results in an increase in net protein catabolism and an increase in creatinine excretion; 2) sweat losses are an important route for urea excretion during exercise; 3) there is no evidence of a disproportionate increase in breakdown of myofibrillar contractile proteins; and 4) in spite of the increase in the rate of protein catabolism, protein is only a minor source of energy during light to moderate exercise.
Effect of epinephrine on glucose metabolism in humans: contribution of the liver
Authors: Sherwin R. S. , Sacca L.
Published: December 2017

Epinephrine causes a prompt increase in blood glucose concentration in the postabsorptive state. This effect is mediated by a transient increase in hepatic glucose production and an inhibition of glucose disposal by insulin-dependent tissues. Epinephrine augments hepatic glucose production by stimulating glycogenolysis and gluconeogenesis. Although its effect on glycogenolysis rapidly wanes, hyperglycemia continues because the effects of epinephrine on gluconeogenesis and glucose disposal persist. Epinephrine-induced hyperglycemia is markedly accentuated by concomitant elevations of glucagon and cortisol or in patients with diabetes. In both cases, the effect of epinephrine on hepatic glucose production is converted from a transient to a sustained response, thereby accounting for the exaggerated hyperglycemia. During glucose feeding, mild elevations of epinephrine that have little effect on fasting glucose levels cause marked glucose intolerance. This exquisite sensitivity to the diabetogenic effects of epinephrine is accounted for by its capacity to interfere with each of the components of the glucoregulatory response, i.e., stimulation of splanchnic and peripheral glucose uptake and suppression of hepatic glucose production. Our findings suggest that epinephrine is an important contributor to stress-induced hyperglycemia and the susceptibility of diabetics to the adverse metabolic effects of stress.
Induction of sugar uptake response to insulin by serum depletion in fusing L6 myoblasts
Authors: Klip A. , Li G. , Logan W. J.
Published: December 2017

The L6 muscle cell line is proposed as an excellent cell culture system for studying glucose transport and its regulation by serum and insulin throughout myogenesis. The rate of hexose uptake decreased after cell fusion. Fetal calf serum (5 h) stimulated hexose uptake, and serum deprivation depressed it. Both effects were prevented by cycloheximide. Insulin stimulated the uptake of either 2-deoxy-D-glucose or 3-O-methyl-D-glucose provided that the basal rate was previously depressed by serum deprivation. The response to the hormone was significant only after the onset of cell fusion. Stimulation of transport was observed within the first 10 min after insulin administration and was insensitive to cycloheximide. Half-maximal stimulation of uptake was obtained with 5 X 10(-8) M insulin in 1% albumin solutions. Basal and insulin-stimulated uptake showed equal sensitivity to cytochalasin B. However, they differed in their sensitivity to extracellular Ca2+: basal transport was depressed, whereas insulin-stimulated transport was further enhanced in Ca2+-free media. Advantages of the cell culture system are discussed.
Role of the kidney in metabolism of gonadotropins in rats
Authors: Emmanouel D. S. , Stavropoulos T. , Katz A. I.
Published: December 2017

The role of the kidney in the metabolic disposal of homologous gonadotropins [renal luteinizing hormone (rLH) and renal follicle-stimulating hormone (rFSH)] was studied in rats. In analogy with other protein hormones, renal mechanisms contributed importantly to their metabolic clearance rates (MCR), which were profoundly and comparably decreased following nephrectomy (by 94 and 78% for rLH and rFSH, respectively). Absolute MCR and renal organ clearance rates of gonadotropins were, however, markedly lower and urinary clearance rates proportionally higher than those of nonglycosylated protein hormones reported previously. Nonetheless, handling of both LH and FSH by the kidney probably involves, in addition to their excretion in the urine, also intrarenal degradation because their urinary clearance rates accounted for at most a third of their respective MCR, considerably less than the striking reduction of MCR seen after acute renal ablation. Moreover, losses of LH immunoreactivity across the renal circulation were over and above those accountable for by urinary excretion alone. Thus, handling of gonadotropins by the kidney differs from that of nonglycoprotein hormones both in magnitude and in that it involves, in addition to intrarenal degradation, also substantial urinary excretion, a pattern that appears to be representative of the way the kidney disposes of glycoprotein hormones in general.
Brown adipose tissue after ventromedial hypothalamic lesions in rats
Authors: Saito M. , Minokoshi Y. , Shimazu T.
Published: December 2017

The interscapular brown adipose tissue (IBAT) from obese rats with lesions of the ventromedial hypothalamus (VMH) was approximately 5 times heavier than those from controls. This hypertrophy of IBAT was associated with a marked enlargement of constituent adipocytes and their apparent transformation from multiloculated structure of lipid droplets into the uniloculated structure. The rate of fatty acid synthesis in IBAT of the obese rats was less than one-tenth of that in control rats and approximated the value in white adipose tissue (WAT) when they were starved for 24 h. When rats were fed, the synthetic rate was increased, but the lipogenic response of IBAT in the obese rats was much greater than that in controls, the extent of the response being comparable to that of WAT. The IBAT temperature rose rapidly on electrical stimulation of the sympathetic nerves to the tissue in control rats, whereas the temperature response was reduced markedly in the obese rats. It was suggested that thermogenesis in BAT was impaired in obese rats with VMH lesions by decreasing triglyceride turnover in BAT, probably due to dysfunction of the sympathetic nervous system and a consequent transformation of BAT into WAT.
Thermic effect of food after ingested versus tube-delivered meals
Authors: Hill J. O. , DiGirolamo M. , Heymsfield S. B.
Published: December 2017

We compared, in six subjects, the thermic effect of food (TEF) after the ingestion of a test meal with that observed after the delivery of an equivalent test meal directly into the stomach through a nasogastric tube. TEF was measured after each test meal (i.e., ingested or tube delivered) until postprandial metabolic rate was not different from fasting metabolic rate (as measured at approximately the same time of day on a previous day). TEF after the tube-delivered meal was not significantly different in magnitude or duration from TEF after the ingested meal. The two types of meals also resulted in similar changes in respiratory quotient. These results suggest that the majority of TEF arises after the food reaches the stomach and that very little of TEF is produced by sensory factors or by the mechanical aspects of eating.
Recycling of an amino acid label with prolonged isotope infusion: implications for kinetic studies
Authors: Schwenk W. F. , Tsalikian E. , Beaufrere B. , Haymond M. W.
Published: December 2017

To investigate whether recycling of a labeled amino acid would occur after 24 h of infusion, two groups of normal volunteers were infused with [3H]leucine and alpha-[14C]-ketoisocaproate for 4 h and [2H3]leucine for either 4 or 24 h (groups I and II, respectively). Entry of [2H3 )leucine at steady state into the plasma space was indistinguishable from its infusion rate for group I but 30% higher (P less than 0.001) than this rate for group II, demonstrating significant recycling of label. After discontinuation of the infusions, isotope disappearance from the plasma space was followed for 2 h. The 3H and 14C decay data for both groups suggest that plasma leucine and alpha-ketoisocaproate are derived from a single intracellular pool in the postabsorptive state. In group I, the 3H and 2H labels decayed identically; whereas, in group II, the decay of [2H3]-leucine and alpha-[2H3]ketoisocaproate was slower (P less than 0.01) than the decay of [3H]leucine and alpha-[3H]ketoisocaproate, confirming re-entry of label after a 24-h infusion. Therefore kinetic values calculated from models assuming no recycling of labeled amino acids are most likely not quantitative and must be interpreted with care when flux does not change or decreases.
Regulation of plasma vasopressin in insulin-dependent diabetes mellitus
Authors: Zerbe R. L. , Vinicor F. , Robertson G. L.
Published: December 2017

Patients with uncontrolled insulin-dependent diabetes mellitus have elevations in plasma vasopressin that cannot be accounted for totally by recognized osmotic or nonosmotic stimuli. To investigate the possibility that regulation of vasopressin secretion is abnormal in this disease, we characterized the vasopressin response to osmotic and hemodynamic stimuli in five uncomplicated, well-controlled insulin-dependent diabetics, and compared the results with those found in nondiabetic volunteers. During osmotic stimulation with hypertonic saline, plasma vasopressin increased in close linear correlation with plasma osmolality or sodium in both groups. However, in the diabetics, the lines describing the relationships between plasma sodium and vasopressin were shifted significantly to the left of normal, suggesting resetting of the osmostat. This shift was not due to abnormal stimulation by hyperglycemia, because increasing plasma glucose and osmolality by intravenous infusion of hypertonic dextrose produced no increase in plasma vasopressin in diabetics or normals. Tilt tests produced a slightly exaggerated increase in plasma vasopressin in diabetics, but their basal and upright pulse rate, blood pressure, plasma renin activity, norepinephrine, and hematocrit were all normal. The results indicate that in diabetic patients the osmoreceptor for osmotic regulation of vasopressin secretion is reset in such a way that higher plasma vasopressin levels are observed at comparable levels of plasma sodium. The exact cause and consequence of this abnormality remain to be determined.