Miracle-dz/UniFAR-FTUs huggingface dataset:
Serum leptin concentrations in infants: effects of diet, sex, and adiposity.

BACKGROUND Leptin, the product of the obese (ob) gene, is a regulator of food intake and energy metabolism. Immunoreactive leptin was detected recently in breast milk and it has been hypothesized that leptin may be absorbed and may contribute to differences in body composition between breast-fed and formula-fed infants. OBJECTIVE The objective was to evaluate whether diet, adiposity, or sex affect plasma leptin in breast-fed and formula-fed infants. DESIGN Venous blood samples were drawn from healthy, exclusively breast-fed or formula-fed Swedish infants at 1, 4, and 6 mo of age (n = 193) and from 12-mo-old Finnish infants (n = 79). Anthropometric measurements were made and plasma samples were analyzed for leptin, insulin, and glucose. RESULTS There were no significant differences in plasma leptin between formula-fed and breast-fed infants at 1 and 4 mo of age, whereas formula-fed infants had significantly higher ( approximately 5%) leptin concentrations at 6 mo of age. Similar results were observed after correction for BMI. Plasma leptin was 15-25% higher in female than in male infants at 1, 4, and 12 mo of age (P < 0.05), also after correction for BMI. When all infants were analyzed together, a positive correlation (r = 0.34, P < 0.0001) was found between plasma leptin and BMI. Very low leptin concentrations were found in breast milk after centrifugation and the high concentrations reported previously were likely due to interference in the assay by milk fat. CONCLUSIONS Plasma leptin concentrations are not higher in breast-fed than in formula-fed infants; however, sex and adiposity affect leptin concentrations even at this early age.
Bioconversion of vaccenic acid to conjugated linoleic acid in humans.

BACKGROUND Vaccenic acid (11-trans octadecenoic acid; VA), a major trans fatty acid in the fat of ruminants, is produced in the rumen and converted in tissues to rumenic acid (9-cis, 11-trans octadecenoic acid; RA), an isomer of conjugated linoleic acid, by Delta(9)-desaturase. There are indications that this conversion also occurs in humans. OBJECTIVE The aim of this controlled intervention was to study the conversion of VA to RA in humans after consumption of diets with increasing amounts of VA. DESIGN Thirty healthy subjects consumed a baseline diet rich in oleic acid for 2 wk. The subjects were then divided into 3 groups (n = 10 per group) and provided a diet containing 1.5, 3.0, or 4.5 g VA/d for 9 d. All diets contained equal amounts of macronutrients and differed only in their fatty acid compositions. The fats were mixed into conventional foods, and nearly all food was provided during the study. RESULTS The proportion of VA in serum total fatty acids increased 94%, 307%, and 620% above baseline with the 1.5-, 3.0-, and 4.5-g diets, respectively. This was associated with a linear increase in the proportion of RA. The conversion rate was 19% on average, with significant interindividual differences with all 3 intakes of VA. The urinary excretion of 8-iso-prostaglandin F(2alpha) increased in all groups (P < 0.001). CONCLUSIONS The results quantify the desaturation of VA to RA in humans. Conversion is likely to contribute significantly to the amount of RA available to the body, and dietary intakes of VA should thus be taken into account when predicting RA status.
Dietary copper deficiency alters protein and lipid composition of murine lymphocyte plasma membranes.

Protein and lipid analyses were conducted on isolated erythrocyte and lymphocyte plasma membranes from 7-wk-old male C57BL copper-deficient and copper-supplemented mice to investigate mechanisms for the altered immunity that accompanies dietary copper deficiency. Beginning at parturition, dams were fed a diet low in copper (0.5 mg/kg) and the offspring were weaned to this diet. Half the dams and their respective offspring received supplemental copper (20 mg/L) in the drinking water (+Cu) and served as controls. Unsupplemented offspring (-Cu) had lower activity of cuproenzymes serum ceruloplasmin, spleen and thymus cytochrome-c oxidase and copper, zinc-superoxide dismutase. The -Cu mice exhibited anemia, splenomegaly and thymic atrophy. Based on the marker enzyme alkaline phosphodiesterase I (APDE-I), lymphocyte plasma membranes were enriched 7- to 10-fold for spleen and thymus, respectively, after discontinuous sucrose density centrifugation. The activity of APDE-I was higher in spleen and thymus samples from -Cu mice than from those of +Cu mice for both crude homogenates and purified plasma membranes. Proteins were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by silver staining. A yellow-appearing band, Mr 74,000, present in all splenic membrane samples from +Cu mice was not evident in the samples from -Cu mice. Fatty acid methyl esters (FAME) were quantified by gas chromatography. Compared to splenic membranes from +Cu mice, the samples from -Cu mice demonstrated significant changes in all FAME (lower 16:0, 18:0 and 20:3n-6 and higher 18:1n-9, 18:2n-6 and 20:4n-6), including a higher unsaturation index. FAME composition of erythrocyte ghosts from -Cu mice demonstrated similar changes. (ABSTRACT TRUNCATED AT 250 WORDS)
Multi-robot Coverage with Dynamic Coverage Information Compression

We consider the problem of distributed terrain or area coverage of an initially unknown environment using a set of mobile robots. We describe a distributed algorithm that is able to solve the distributed coverage problem without having each robot exchange its complete coverage map with other robots. The central part of our technique is a compression algorithm used by a robot to approximate the regions that have been previously covered and a fitness function that calculates the degree of accuracy of the approximated coverage information. The operation of our coverage algorithm is evaluated through experiments on simulated as well as physical Corobot robots. We have quantified the extent of overhead introduced by our coverage algorithm to prevent robots from performing repeated coverage. Overall, our results show that the robots are able to cover the environment within different environment settings while significantly reducing the amount of coverage information communicated between different robots.
Metal MEMS tools for beating-heart tissue removal

A novel robotic tool is proposed to enable the surgical removal of tissue from inside the beating heart. The tool is manufactured using a unique metal MEMS process that provides the means to fabricate fully assembled devices that incorporate micron-scale features in a millimeter scale tool. The tool is integrated with a steerable curved concentric tube robot that can enter the heart through the vasculature. Incorporating both irrigation and aspiration, the tissue removal system is capable of extracting substantial amounts of tissue under teleoperated control by first morselizing it and then transporting the debris out of the heart through the lumen of the robot. Tool design and robotic integration are described and ex vivo experimental results are presented.
Decreased tumor necrosis factor-induced adhesion of human monocytes to endothelial cells after moderate alcohol consumption.

BACKGROUND Moderate alcohol consumption protects against ischemic heart disease, possibly through an antiinflammatory effect. However, little is known about the mechanisms by which alcohol may interfere in the development of atherosclerosis. OBJECTIVE We analyzed the effects of 2 alcoholic beverages with high (red wine) or low (gin) polyphenolic content on human monocyte adhesion to an endothelial cell line (Ea.hy926). DESIGN This was a randomized, crossover trial with 8 healthy men. After a washout period, the subjects received 30 g ethanol/d as red wine or gin for 28 d. Before and after each intervention, a dietary survey and laboratory analysis were performed. Adhesion of human monocytes to endothelial cells was measured in basal and stimulated [by tumor necrosis factor alpha (TNF-alpha)] conditions. Adhesion molecules involved in monocyte-endothelium interactions were determined on the cell surface. RESULTS The mean expression of very late activation antigen 4 on monocytes significantly decreased after red wine intake [by 18% (95% CI: 33%, 3%); P = 0.022]. Monocyte adhesion significantly increased after TNF-alpha stimulation of endothelial cells. This increase, however, was 39% less (95% CI: 48%, 35%; P = 0.049) after gin intake than after the respective washout period and was nearly abolished by red wine intake [96% less than after the respective washout period (95% CI: 142%, 76%); P < 0.001]. The reduction after red wine intake was significantly different from that after gin intake (P = 0.014). CONCLUSIONS TNF-alpha-induced adhesion of monocytes to endothelial cells was virtually abolished after red wine consumption but was only partially reduced after gin consumption. This effect may be due to the down-regulation of adhesion molecules on the monocyte surface.
Ultrarapid delayed rectifier current inactivation in human atrial myocytes: properties and consequences.

The ultrarapid delayed rectifier current ( I K,ur) plays a significant role in human atrial repolarization and is generally believed to show little rate dependence because of slow and partial inactivation. This study was designed to evaluate in detail the properties and consequences of I K,urinactivation in isolated human atrial myocytes. I K,ur inactivated with a biexponential time course and a half-inactivation voltage of -7.5 ± 0.6 mV (mean ± SE), with complete inactivation during 50-s pulses to voltages positive to +10 mV (37°C). Recovery from inactivation proceeded slowly, with time constants of 0.42 ± 0.06 and 7.9 ± 0.9 s at -80 mV (37°C). Substantial frequency dependence was observed at 37°C over a clinically relevant range of frequencies. Inactivation was faster and occurred at more positive voltages at 37°C compared with room temperature. The voltage and time dependencies of Kv1.5 inactivation were studied in Xenopus oocytes to avoid overlapping currents and strongly resembled those of I K,ur in native myocytes. We conclude that, while I K,urinactivation is slow, it is extensive, and slow recovery from inactivation confers important frequency dependence with significant consequences for understanding the role of I K,ur in human atrial repolarization.
Diffractive optical elements made from photonic metamaterials

The excitation of surface plasmon polaritons in metallic nanostructures significantly enhances light-matter interactions at sub-wavelength scales. This enables novel optical effects that rely on artificial materials, so-called metamaterials. Metamaterials are made from densely packed and sufficiently small nanostructured unit cells. The purpose of metamaterials is to act comparable to bulk materials but with effective properties that can be tailored by the geometry of the unit cells. However, recently it became obvious that many appealing applications are already in reach by employing an ultrathin layer of metamaterial. Exploiting the metamaterials’ primary optical properties in the form of their dispersive complex reflection and transmission coefficients, single functional layers instead of bulk metamaterials are already sufficient for achieving sophisticated device properties. In particular, if the unit cells change across the functional layer, a new class of devices can be perceived that shape the light in the far-field according to predefined patterns. These metamaterial layers, usually referred to as metasurfaces, possess major advantages when compared to traditional optical elements. Here, we provide an overview of the burgeoning field of research that explores metasurfaces to affect an incident field spatially and spectrally in a deterministic way to enable functional diffractive optical elements.
Emulsification and fatty acid chain length affect the kinetics of [14C]-medium-chain triacylglycerol utilization by neonatal piglets.

In vivo oxidation kinetics of medium-chain triglycerides (MCT) composed of [1-14C]hexanoate (tri-6:0) or [1-14C]octanoate (tri-8:0) were compared after being fed to day-old piglets (1.4 kg; n = 4/treatment). Animals were fitted with arterial and oro-gastric catheters and placed into respiration chambers held at 35 degrees C. The radiolabeled MCT were fed in equimolar amounts (6.5 mmol/kg0.75), in either nonemulsified form or as 30% (v/v) emulsions, using polyoxyethylene sorbitan monooleate as an emulsifier. Expired CO2 was quantified and specific radioactivity (Bq/mumol) determined at 20-min intervals over 24 h, and serial blood samples were drawn for measurement of plasma hexanoate and octanoate by HPLC. The rate [mumol/(h.kg0.75)] and extent (mmol/kg0.75) of MCT oxidative utilization (i.e., composite of digestion, absorption and oxidation) were calculated from the kinetics of 14CO2 expiration. Emulsification increased both the rate and extent of MCT oxidative utilization by > 20% regardless of fatty acid chain length (P < 0.05). Maximal MCT oxidation rates occurred at 3.5 h after feeding and were sufficient to meet up to 48% of the piglets' energy expenditure. The maximal rate of tri-6:0 oxidative utilization exceeded that of tri-8:0 by 37% (P < 0.05), but the extent of utilization was not affected by fatty acid chain length. Plasma medium-chain fatty acid concentrations were in agreement with these observations, being higher in pigs fed emulsified MCT than in pigs fed nonemulsified MCT (P < 0.05) and being higher in pigs fed tri-6:0 than in animals fed tri-8:0 (P < 0.05). Collectively, these data demonstrate that newborn piglets can effectively digest, absorb and oxidize MCT, that utilization is improved with emulsification, and that tri-6:0 is utilized more rapidly than tri-8:0.
Heart rate dynamics during accentuated sympathovagal interaction.

Concomitant sympathetic and vagal activation can occur in various physiological conditions, but there is limited information on heart rate (HR) behavior during the accentuated sympathovagal antagonism. Beat-to-beat HR and blood pressure were recorded during intravenous infusion of incremental doses of norepinephrine in 18 healthy male volunteers (mean age 23 ± 5 yr). HR and blood pressure spectra and two-dimensional Poincaré plots were generated from the baseline recordings and from the recordings at different doses of norepinephrine. The mean blood pressure increased (from 90 ± 7 to 120 ± 9 mmHg, P < 0.001), HR decreased (from 60 ± 9 to 48 ± 7 beats/min, P < 0.001), and the high-frequency spectral component of HR variability increased ( P < 0.001) during the norepinephrine infusion as evidence of accentuated sympathovagal interaction. Abrupt aperiodic changes in sinus intervals that were not related to respiratory cycles or changes in blood pressure occurred in 14 of 18 subjects during the norepinephrine infusions. These fluctuations in sinus intervals resulted in a complex or parabola-shaped structure of the Poincaré plots of successive R-R intervals and a widening of the high-frequency spectral peak. In four subjects, the abrupt fluctuations in sinus intervals were followed by a sudden onset of fixed R-R interval dynamics with a loss of respiratory modulation of HR, resulting in a torpedo-shaped structure of the Poincaré plots. These data show that HR behavior becomes remarkably unstable during accentuated sympathovagal interaction, resembling stochastic dynamics or deterministic chaotic behavior. These features of HR dynamics can be better identified by dynamic analysis of beat-to-beat behavior of R-R intervals than by traditional analysis techniques of HR variability.
Receptor-mediated vascular and metabolic actions of endothelin-1 in canine small intestine

King-VanVlack, Cheryl E. , Jeffrey D. Mewburn, and Christopher K. Chapler. Receptor-mediated vascular and metabolic actions of endothelin-1 in canine small intestine. Am. J. Physiol. 276 (Gastrointest. Liver Physiol. 39): G1131– G1136, 1999. —The effects of endothelin-1 (ET-1) infusion on blood flow (Q̇G) and O2 uptake (V̇O2G) were examined in the small intestine of anesthetized dogs (n 5 10). Arterial and venous flows of a gut segment were isolated, and the segment was perfused at constant pressure. Arterial and gut venous blood samples were taken, gut perfusion pressure and Q̇G were measured, and O2 extraction ratio (OERG) and V̇O2G were calculated. ET-1 was infused (0.118 μg·kg21 ·min21 ia) throughout the experiment. In group 1 (n 5 5), ETA receptors were blocked using BQ-123 (0.143 mg·kg21 ·min21 ia) followed by blockade of ETB receptors with BQ-788 (0.145 mg· kg21 ·min21 ia). The order of ETA and ETB receptor blockade was reversed in group 2 (n 5 5). In group 1, the decrease in Q̇G observed with ET-1 infusion was partially reversed with BQ-123; no further change occurred after BQ-788 administration. In group 2, addition of BQ-788 to the infusate further decreased Q̇G, whereas addition of BQ-123 returned Q̇G to a value not different from that with ET-1 infusion alone. These data indicated that ET-1-induced vasoconstriction in the gut was mediated via ETA receptors and that this constriction was buffered by activation of ETB receptors. V̇O2G decreased in proportion to the decrease in Q̇G with ET-1, decreased further with ET-1 plus ETB receptor blockade (group 2), and increased in proportion to the increases in Q̇G with ETA receptor blockade (both groups). No changes in OERG occurred during ETA and ETB receptor antagonism in either group. This study is the first to demonstrate that a flowlimited decrease in gut V̇O2G occurred with infusion of ET-1 in gut vasculature. An intriguing and novel finding was that, during O2 limitation, OERG was only 50% of that normally associated with ischemia in this tissue.
The measurement of ion mobility by using an axisymmetric ion-flow anemometer

The mobility of a negative ion cloud generated in atmospheric and in reduced air pressure was measured with an axisymmetric configuration of an ion-flow anemometer. The measuring apparatus consists of an emitter assembly, a collecting plate and a detecting ring. When a high voltage pulse was applied to the emitter assembly, an ion cloud was emitted and moves toward the collector. One of the results previously obtained was that the mobility of ion cloud changes with the amount of charge emitted, contrary to the constant value as customary believed. This experiment was further pursued by changing various parameters, such as electrode configuration and applied voltage. The amount of emitted charge from the emitter assembly can be varied by changing applied pulse voltage and/or pulse duration. The experimental results indicated that the mobility of ion increased with the amount of emitted charge and the extrapolated value to zero-charge agreed well with the published data. The values of mobility for different air condition, varying pressure and humidity were experimentally obtained. It was also shown that the mobility increases with the decreases of pressure and when humidity increases, the amount of charge emitted decreases, resulting in the reduced mobility.
Altered protein kinase C activation of Na+/Ca2+exchange in mesangial cells from salt-sensitive rats.

The purpose of these studies was to determine whether there is a defect in protein kinase C (PKC) regulation of the Na+/Ca2+exchanger in cultured mesangial cells (MC) from Dahl/Rapp salt-sensitive (S) and salt-resistant (R) rats. R and S MCs were cultured, grown on coverslips, and loaded with fura 2 for measurement of single cell cytosolic calcium concentration ([Ca2+]i) in a microscope-based photometry system. Studies were performed in cells that were exposed to serum (serum fed) and in cells that were serum deprived for 24 h. Baseline [Ca2+]ivalues measured in a Ringer solution containing 150 mM NaCl were similar between R and S MCs in both serum-fed and serum-deprived groups, although baseline [Ca2+]ivalues were uniformly higher in the serum-deprived groups. Exchanger activity was assessed by reducing extracellular Na (Nae) from 150 to 2 mM, which resulted in movement of Na+ out of and Ca2+ into these cells (reverse-mode Na+/Ca2+exchange). PKC was activated in these cells with 15-min exposure to 100 nM phorbol 12-myristate 13-acetate (PMA). In the absence of PMA, the change in [Ca2+]i(Δ[Ca2+]i) with reduction in Nae was similar between R and S MCs in both serum-fed and serum-deprived groups, although the magnitude of Δ[Ca2+]iwas enhanced by serum deprivation. In both serum-fed and serum-deprived groups, PMA significantly increased Δ[Ca2+]iin R but not S MCs. Upregulation of exchanger activity in R MCs could be abolished by prior 24-h exposure to PMA, a maneuver that downregulates PKC activity. Other studies were performed to evaluate exchanger protein expression using monoclonal and polyclonal antibodies. Immunoblots of PMA-treated cells revealed an increase in the levels of 70- and 120-kDa proteins in the crude membrane fraction of R but not S MCs, an increase which was abrogated by prior 24-h PMA pretreatment and corresponded to reduction in the 70-kDa protein in the crude cytosolic fraction. These data demonstrate that PKC enhances Na+/Ca2+exchange activity in MCs from R but not from S rats, suggesting that there may be a defect in the PKC-Na+/Ca2+exchange regulation pathway in MCs of S rats.
Regulation of the Na+/H+exchanger in fibroblasts overexpressing the Na+/Ca2+exchanger.

To assess the role of Ca2+in regulation of the Na+/H+exchanger (NHE1), we used CCL-39 fibroblasts overexpressing the Na+/Ca2+exchanger (NCX1). Expression of NCX1 markedly inhibited the transient cytoplasmic Ca2+ rise and long-lasting cytoplasmic alkalinization (60-80% inhibition) induced by α-thrombin. In contrast, coexpression of NCX1 did not inhibit this alkalinization in cells expressing the NHE1 mutant with the calmodulin (CaM)-binding domain deleted (amino acids 637-656), suggesting that the effect of NCX1 transfection involves Ca2+-CaM binding. Expression of NCX1 only slightly inhibited platelet-derived growth factor BB-induced alkalinization and did not affect hyperosmolarity- or phorbol 12-myristate 13-acetate-induced alkalinization. Downregulation of protein kinase C (PKC) inhibited thrombin-induced alkalinization partially in control cells and abolished it completely in NCX1-transfected cells, suggesting that the thrombin effect is mediated exclusively via Ca2+ and PKC. On the other hand, deletion mutant study revealed that PKC-dependent regulation occurs through a small cytoplasmic segment (amino aids 566-595). These data suggest that a mechanism involving direct Ca2+-CaM binding lasts for a relatively long period after agonist stimulation, despite apparent short-lived Ca2+ mobilization, and further support our previous conclusion that Ca2+- and PKC-dependent mechanisms are mediated through distinct segments of the NHE1 cytoplasmic domain.
Racial differences in skeletal calcium retention in adolescent girls with varied controlled calcium intakes.

BACKGROUND Higher bone mass in blacks than in whites has been related to greater calcium utilization efficiency. Dietary calcium requirements for maximal skeletal calcium accretion during puberty may differ between the races. OBJECTIVE This study compared the relation between calcium intake and calcium retention in black and white adolescent girls. DESIGN A range of controlled calcium intakes (760-1981 mg Ca/d) were used in 3-wk controlled balance studies. Some subjects were studied more than once; a total of 182 observations from 55 black girls and 66 white girls were analyzed. RESULTS Blacks had 185 +/- 32 mg/d greater mean skeletal calcium retention than did whites (P < 0.0001) at all calcium intakes as a result of significantly greater net calcium absorption (P < 0.001) and lower calcium excretion (P < 0.0001). CONCLUSIONS Dietary calcium requirements did not differ with race. Higher calcium retention at all calcium intakes during adolescence may underlie the higher bone mineral content of adult blacks than of adult whites.