HC Condition Research Articles

Effects of coffee intake on skeletal muscle microvascular reactivity at rest and oxygen extraction during exercise: a randomized cross-over trial.

The effects of coffee ingestion on skeletal muscle microvascular function are not well understood. This study aimed to investigate the acute effects of coffee intake with varying levels of caffeine on skeletal muscle microvascular reactivity at rest and oxygen extraction during maximal incremental exercise in physically active individuals. Twenty healthy young male participants were administered coffee with low caffeine (3 mg/kg body weight; LC), high caffeine (6 mg/kg body weight; HC), and placebo (decaf) in different sessions. Skeletal muscle reactivity indexes, including tissue saturation index 10s slope (TSI10) and TSI half time recovery (TSI ½) following 5-minute ischemia were measured at rest and were measured at baseline and post-coffee consumption using near-infrared spectroscopy (NIRS). Post-coffee intake, NIRS was also used to measure microvascular oxygen extraction during exercise via maximal incremental exercise. Peak oxygen consumption and peak power output (Wpeak) were simultaneously evaluated. Post-coffee consumption, TSI10 was significantly higher in the LC condition compared to placebo (p = 0.001) and significantly higher in the HC condition compared to placebo (p < 0.001). However, no difference was detected between LC and HC conditions (p = 0.527). HC condition also showed significant less TSI ½ compared to placebo (p = 0.005). However, no difference was detected for microvascular oxygen extraction during exercise, despite the greater Wpeak found for HC condition (p < 0.001) compared to placebo. Coffee ingestion with high caffeine level (6 mg/kg body weight) significantly enhanced skeletal muscle reactivity at rest. However, the improvement of exercise performance with coffee intake is not accompanied by alterations in muscle oxygen extraction.

Examining the role of stimulus complexity in item and associative memory.

Episodic memory comprises memory for individual information units (item memory) and for the connections among them (associative memory). In two experiments using an object pair learning task, we examined the effect of visual stimulus complexity on memory encoding and retrieval mechanisms and on item and associative memory performance. Subjects encoded pairs of black monochrome object images (low complexity, LC condition) or color photographs of objects (high complexity, HC condition) via interactive imagery, and subsequently item and associative recognition were tested. In Experiment 1, event-related potentials (ERPs) revealed an enhanced frontal N2 during encoding and an enhanced late posterior negativity (LPN) during item recognition in the HC condition, suggesting that memory traces containing visually more complex objects elicited a stronger effort in reconstructing the past episode. Item memory was consistently superior in the HC compared to the LC condition. Associative memory was either statistically unaffected by complexity (Experiment 1) or improved (Experiment 2) in the HC condition, speaking against a tradeoff between resources allocated to item versus associative memory, and hence contradicting results of some prior studies. In Experiment 2, in both young and older adults, both item and associative memory benefitted from stimulus complexity, such that the magnitude of the age-related associative deficit was not influenced by stimulus complexity. Together, these results suggest that if familiar objects are presented in a form that exhibits a higher visual complexity, which may support semantic processing, complexity can benefit both item and associative memory. Stimulus properties that enhance item memory can scaffold associative memory in this situation.

Effect of catecholamines stimulation via hand cooling and the priming effect on the oxygen consumption kinetics

Introduction&#x0D; Priming effect has been shown to accelerate the oxygen consumption (V̇O2) kinetics. This phenomenon could be explained by muscle oxygen (O2) enhanced delivery, motor unit recruitment or intracellular O2 enhanced utilization (Goulding et al. 2023). Catecholamines such as epinephrine (E) and norepinephrine (NE) are known to impact the cardiovascular system as well as the respiratory system and metabolic effects (Zouhal et al. 2008). The aim of this study is two folds. Observing the effect of increased E and NE induced by cold-water hand immersion on V̇O2 kinetic during heavy intensity exercise bout (HCWR). Compare the effect of cold-water hand immersion and previous HCWR on V̇O2 kinetic to see if the sympathetic system could partially explain the priming effects.&#x0D; Methods&#x0D; Ten healthy active males (mean ± SD, age 23 ± 5 years, body mass 71 ± 6.5 kg) participated in this study. An incremental test was performed on ergometer to prescribe the intensity for the HCWR exercise (∆ 25%). Participants did an 8 min HCWR normal bout (NO), followed by 8 min rest and a second bout (SB) and hand cooling bout (HC) at heavy intensity in a randomized order. For the HC condition, participants put hands in cold water (0°C) for 2 min then directly did the HCWR. Blood samples has been taken at rest, before and directly after the HCWR.&#x0D; Results&#x0D; Just before exercise, all conditions were different, but HC E (1.095 ± 0.64 nmol/ml) increased by 347% while HC NE (6.98 ± 1.89 nmol/ml) matched values from SB NE (6.89 ± 2.22 nmol/ml). At the end of exercise, no significant difference has been found between NO E (1.44 ± 1.06) and HC E (1.54 ± 1.38 nmol/ml) while SB E (2.35 ± 1.55 nmol/ml) was significantly higher than both conditions but no differences have been found between HC (20.15 ± 8.76 nmol/ml) and SB (20.41 ± 9.74 nmol/ml) NE. V̇O2 kinetic has been sped up for both HC and SB by increasing the absolute primary prime amplitude of HC (33.88 ± 0.96 ml/min/kg),SB (34.60 ± 0.86ml/min/kg) compared to NO (32.75 ± 0.65 ml/min/kg) and reducing the prime amplitude of HC (3.22 ± 0.51 ml/min/kg), SB (2.90 ± 0.64 ml/min/kg) vs NO (3.87 ±0 .56 ml/min/kg) of the slow component of V̇O2.&#x0D; Discussion/Conclusion&#x0D; Catecholamines stimulation via hand cooling accelerated the V̇O2 kinetics enhancing the primary phase and reducing the slow component. This effect seemed to follow the priming effect but with less intensity. Increased O2 delivery appeared to be a common feature of both conditions, Motor neuron excitability due to increased NE was also a likely hypothesis, as both HC and SB had the same values just before exercise. Finally, intra-muscular enhancement illustrated by improved intracellular partial pressure kinetics and mitochondrial O2 utilization might explain the effects of catecholamines and part of the priming effect. Mitochondrial “warm-up” could be influenced by both catecholamines and priming effect resulting in a better production of adenosine triphosphate.&#x0D; References&#x0D; Goulding, R. P., Burnley, M., &amp; Wüst, R. C. I. (2023). How priming exercise affects oxygen uptake kinetics: From underpinning mechanisms to endurance performance. Sports Medicine, 53, 959-976. https://doi.org/10.1007/s40279-023-01832-1&#x0D; Zouhal, H., Jacob, C., Delamarche, P., &amp; Gratas-Delamarche, A. (2008). Catecholamines and the effects of exercise, training and gender. Sports Medicine 38, 401-423. https://doi.org/10.2165/00007256-200838050-00004

Effects of alternating heat and cold stimulation using a wearable thermo-device on subjective and objective shoulder stiffness

BackgroundTechnological innovations have allowed the use of miniature apparatus that can easily control and program heat and cold stimulations using Peltier elements. The wearable thermo-device has a potential to be applied to conventional contrast bath therapy. This study aimed to examine the effects of alternating heat and cold stimulation (HC) using a wearable thermo-device on subjective and objective improvement of shoulder stiffness.MethodsTwenty healthy young male individuals (20.3 ± 0.6 years) participated in this study. The interventions were randomly conducted under four conditions, including HC, heat stimulation, cold stimulation, and no stimulation on their bilateral trapezius muscle, after a 30-min typing task. Each intervention was administered at least 1 week apart. The analyzed limb was the dominant arm. Muscle hardness was assessed using a portable muscle hardness meter, as well as the skin temperature over the stimulated area. After each condition, the participants were asked for feedback regarding subjective improvement in refreshed feelings, muscle stiffness, and muscle fatigue using an 11-point numerical rating scale.ResultsWith regard to muscle hardness, only the HC condition significantly decreased from 1.43 N to 1.37 N (d = 0.44, p < 0.05). Additionally, reduced muscle hardness in HC condition was associated with the degree of skin cooling during the intervention (cold max: r = 0.634, p < 0.01; cold change: r = −0.548, p < 0.05). Subjective improvement in refreshed feelings, muscle stiffness, and muscle fatigue was determined in the HC and heat stimulation conditions compared with the no stimulation condition (p < 0.01 and p < 0.05, respectively). Moreover, the HC condition showed significantly greater improvements in muscle stiffness and fatigue compared to the cold stimulation condition (p < 0.05).ConclusionsThe current study demonstrated that HC promoted not only better subjective symptoms, such as muscle stiffness and fatigue, but also lesser muscle hardness. Furthermore, an association was observed between the degree of skin temperature cooling and reduced muscle hardness during HC. Further investigations on the ratio and intensity of cooling should be conducted in the future to establish the optimal HC protocol for muscle stiffness or fatigue.Trial registrationUMIN000040620. Registered 1 June 2020

Overload of anxiety on postural control impairments in chronic stroke survivors: The role of external focus and cognitive task on the automaticity of postural control.

BackgroundDespite the high prevalence of anxiety among chronic stroke survivors and evidence of its negative effects on postural control in healthy subjects, it is unclear whether anxiety also affects postural control in these patients. Recent evidence of improved postural control of healthy subjects by distracting the attention using an external focus (EF) or cognitive task, raises the question of whether similar benefits would be observed in stroke survivors. Thus, the current study aimed to investigate the effects of anxiety and distracting the attention on postural control of chronic stroke survivors in terms of both postural sway measures and neuromuscular regulation.MethodsPostural sway measures and ankle muscle activity of chronic stroke survivors with the high and low level of anxiety (HA-stroke (n = 17), and LA-stroke (n = 17), respectively) and age-, sex-, height-, and weight-matched healthy subjects (n = 17) were assessed while standing on rigid and foam surfaces under following conditions: baseline, internal focus (IF), EF, simple and hard cognitive tasks (SC and HC, respectively).ResultsStroke survivors, particularly HA-stroke participants, showed greater postural sway measures (i.e. postural instability) and enhanced co-contraction of ankle muscles (i.e. stiffening of the neuromuscular system) compared with healthy subjects. As opposed to baseline and IF conditions, postural instability and neuromuscular stiffening significantly reduced in EF condition and decreased more in cognitive task conditions, particularly HC condition.ConclusionsThe results suggest that anxiety enhances stroke-induced postural instability promoting improper neuromuscular control of posture with stiffening strategy, which can be alleviated by EF and cognitive tasks.

1288-PUB: Acute Inflammatory Response of Breaking Up Prolonged Sitting with Stair Climbing Exercise Snacks

Understand the acute inflammatory disturbances is important for preventing early diabetes and obesity-related complications. This study aimed to determine whether breaking up prolonged sitting into brief several shorter bouts spread throughout the day (“exercise snacks”) associated a short-term dietary intervention (low- or high-carbohydrate) have the potential to alter the acute inflammatory response. Ten male and female healthy weight (Lean) and overweight-obese (OW) participants were randomized to non-training control group with either low-carbohydrate snack (9h sitting; LC) or matched for total energy high-carbohydrate snacks consumption (9h; sitting) and a high-carbohydrate snacks consumption plus stair-climbing intervention (8X15-30seconds; ACTIVE). The same high-glycemic index meals were consumed at 0, 3 and 6h at each condition. Blood samples were collected at baseline, 180, 360 and 540 minutes to assess Interleukin-6 (IL-6), Tumor necrosis factor-α (TNF-α) and Salivary Immunoglobulin A (SIgA) levels. Mixed models for repeated measures were undertaken to examine differences according to condition x time and with Bonferroni post-hoc test. Change in TNF-α levels was not different within or between conditions from both Lean and OW group (p=0.512). For IL-6 there were a main effect of time at 540min [X2(11)=23.15; p=0.01] only in HC condition for OW group. Regarding to SIgA, Lean group showed higher level of SIgA on Active compared to LC and HC condition in all time-points (p=0.001). In addition, adults with OW showed elevated SIgA levels on LC and HC condition (p=0.001) when compared with same condition from Lean group. Our data suggests that breaking up nine hours of prolonged sitting implicated in reduction of acute inflammatory IL-6 plasma levels. In addition, acute manipulation on diet (low- and high-carbohydrate) resulted in alterations in the response of SIgA, increasing its levels in overweight/obese adults. Disclosure C. Cabral-santos: None. H. Rafiei: None. F. S. Lira: None. J. P. Little: None. Funding Natural Sciences and Engineering Research Council of Canada; Fundação de Amparo a Pesquisa do Estado de São Paulo (2018/17648-7)

Membrane lipid remodeling is required for photosystem II function under low CO2.

Membrane lipid remodeling in plants and microalgae has a crucial role in their survival under nutrient-deficient conditions. Aquatic microalgae have low access to CO2 , an essential carbon source for photosynthetic assimilates; however, 70-90mol% of their membrane lipids are sugar-derived lipids (glycolipids) such as monogalactosyldiacylglycerol (MGDG). In this study, we discovered a new system of membrane lipid remodeling responding to CO2 in Synechocystis sp. PCC 6803, a unicellular, freshwater cyanobacterium. As compared with higher CO2 (HC; 1% CO2 ), under ambient air (lower CO2 : LC), phosphatidylglycerol (PG) content was increased at the expense of MGDG content. To explore the biological significance of this alteration in content, we generated a transformant of Synechocystis sp. PCC 6803 overexpressing sll0545 gene encoding a putative phosphatidic acid phosphate (oxPAP), which produces diacylglycerol that is used for the synthesis of glycolipids, and examined the effect on membrane lipid remodeling and phototrophic growth responding to LC. Photosystem II (PSII) activity and growth rate were inhibited under LC in oxPAP cells. PG content was substantially reduced, and MGDG and sulfoquinovosyldiacylglycerol contents were increased in oxPAP cells as compared with control cells. These phenotypes in oxPAP cells were recovered under the HC condition or PG supplementation. Increased PG content may be required for proper functioning of PSII under LC conditions.

Sacrificial Anion Reduction Mechanism for Electrochemical Stability Improvement in Highly Concentrated Li-Salt Electrolyte

Li-salt concentration has been recently proposed as an important control parameter of reduction stability of electrolytes in lithium-ion battery (LIB). Here we theoretically investigated low (LC) and high (HC) concentration systems of LiN(SO2CF3)2 (Li-TFSA) salt in acetonitrile (AN) solution, to elucidate the mechanism of improving the low reduction stability of AN at the HC condition, by density functional theory based molecular dynamics (DFT-MD) sampling of the solvation character with extra electron(s). We demonstrated that TFSA anions sacrificially accept the reductive electron at the HC condition, which is ascribed to formation of specific network structure and the resulting shift of electron affinity of the anions. We also found that, even in the LC condition, TFSA eventually decomposes with one electron reduction. This sacrificial anion reduction hinders two electron reductive decomposition of AN, leading to improved electrochemical stability. The mechanism may give a guiding principle for the desi...

Light-modulated responses of growth and photosynthetic performance to ocean acidification in the model diatom Phaeodactylum tricornutum.

Ocean acidification (OA) due to atmospheric CO2 rise is expected to influence marine primary productivity. In order to investigate the interactive effects of OA and light changes on diatoms, we grew Phaeodactylum tricornutum, under ambient (390 ppmv; LC) and elevated CO2 (1000 ppmv; HC) conditions for 80 generations, and measured its physiological performance under different light levels (60 µmol m−2 s−1, LL; 200 µmol m−2 s−1, ML; 460 µmol m−2 s−1, HL) for another 25 generations. The specific growth rate of the HC-grown cells was higher (about 12–18%) than that of the LC-grown ones, with the highest under the ML level. With increasing light levels, the effective photochemical yield of PSII (Fv′/Fm′) decreased, but was enhanced by the elevated CO2, especially under the HL level. The cells acclimated to the HC condition showed a higher recovery rate of their photochemical yield of PSII compared to the LC-grown cells. For the HC-grown cells, dissolved inorganic carbon or CO2 levels for half saturation of photosynthesis (K1/2 DIC or K1/2 CO2) increased by 11, 55 and 32%, under the LL, ML and HL levels, reflecting a light dependent down-regulation of carbon concentrating mechanisms (CCMs). The linkage between higher level of the CCMs down-regulation and higher growth rate at ML under OA supports the theory that the saved energy from CCMs down-regulation adds on to enhance the growth of the diatom.

In Vitro and in Vivo Evidence of an Anti-Angiogenic Effect of Lenalidomide in Chronic Lymphocytic Leukemia

AbstractAbstract 1782The exact mechanism of anti-tumor activity of the immunomodulatory drug lenalidomide remains undefined, but it implies the activation of immune effector cells. Little is known concerning the anti-angiogenic properties of lenalidomide in chronic lymphocytic leukemia (CLL) patients.A total of 27 relapsed/refractory CLL patients were treated within a multicenter Phase II trial. Peripheral blood mononuclear cells and plasma samples were collected before and during treatment. Lenalidomide treatment schedule began with 5 mg daily doses and increased by 5 mg daily every two weeks, up to 25 mg daily or maximum tolerated dose. Several angiogenesis-related cytokines were measured by ELISA in plasma. Circulating endothelial cells (CEC), endothelial progenitor cells (EPC), apoptotic CEC (APO-CEC), and activated CEC (aCEC) were evaluated by flow cytometry. In vitro experiments were performed on CLL cells purified from peripheral blood by using CD19Microbeads. Cells were cultured alone (CLL only) or on a EC monolayer (HC condition).First, CLL cells from 9 patients treated in vitro with up to 10 μmol/L of lenalidomide did not show any direct cytotoxic effect. However, an anti-leukemic effect was observed in vivo in our cohort of heavily pre-treated CLL patients. We found a reduction of white blood cell count (WBC, 1×109/L) from 39.9±8.0 before treatment to 15.2±5.2 and 16.0±5.2 after 4 and 12 months of treatment respectively and a decrement of absolute number of lymphocytes from 25.6±6.4 before treatment to 7.9±2.7 and 5.4±2.4 after 4 and 12 months of treatment (p<0.05, Wilcoxon test). To evaluate whether lenalidomide exerts its anti-CLL effect disrupting leukemic cross-talk with endothelial cells, we co-cultured CLL cells (n=9) on EC layer in presence or absence of increasing doses of lenalidomide. All CLL cells cultured on EC layer displayed a significant survival advantage (mean viability, 16% vs. 47% in CLL alone and HC) that was reduced by lenalidomide treatment (28%) (p<0.001).We then evaluated the effect of lenalidomide treatment on circulating endothelial cells in treated CLL patients (n=27). We found that the absolute number of CEC and EPC decreased from 8.2±1.5/μL and 4.7±1.0/μL pre-therapy to 2.1±0.6/μL and 1.0±0.5/μL after 4 months respectively (p=0.002 for CEC and p=0.01 for EPC). Moreover, the percentage of APO-CEC increased from 51% to 84% of the total CEC (p<0.0001). No differences were found in the aCEC subset during treatment. Moreover, we examined the effect of lenalidomide treatment on a panel of angiogenesis-related factors. The plasma levels of vascular endothelial growth factor (VEGF) and thrombospondin-1 (THBS1) showed a significant decrease by month 4 compared to pre-treatment levels (VEGF, 77±13 to 43±8 pg/mL, p=0.014; THBS1, 662±80 to 416±75 ng/mL, p=0.01). Angiogenin plasma levels increased after 4 months of treatment from 441±16 ng/mL to 460±21 ng/mL (p=0.025). No significant differences were detected in plasma levels of basic fibroblast growth factor (bFGF,) and Angiopoietin-1 (Ang1). Angiopoietin-2 (Ang2) showed an increase during the first phase of treatment from 5183 to 8126 pg/mL (p=0.001).Furthermore, patients were grouped under the clinical classification of stable/progressive disease (not responders, NR n=6) and partial response (responders, R n=10). There was an Increased percentage of aCEC detected in NR patients (54% vs. 74% in R and NR at baseline respectively, p=0.039). We also found that VEGF plasma levels significantly decreased during treatment exclusively in the R subset (83±26 pg/mL at baseline to 26±6 pg/mL after 4 months, p=0.007). Moreover, bFGF plasma levels showed a strong decrease in R patients from 168±105 pg/mL at baseline to 41±11 and 19±8 pg/mL after one week and 4 months of treatment (p=0.017 and p=0.005 respectively), whereas increased levels were measured in NR patients from 120±58 pg/mL at baseline to 426±195 and 234±147 pg/mL.Our study provides evidence that the mechanism of action of lenalidomide in CLL patients is mediated not only through the activation of immune effector cells, but also through the modulation of angiogenesis-related factors and disruption of CLL cross-talk with endothelial cells. Of interest, we identified plasmatic factors (VEGF and bFGF) that are correlated with clinical response to lenalidomide. Disclosures:Off Label Use: Lenalidomide, a thalidomide analogue, is an immunomodulatory drug (IMiD) with antitumoural activity reported in various malignant disorders including multiple myeloma and myelodysplastic syndrome (MDS). At preclinical level, lenalidomide has shown to decrease the production of several prosurvival cytokines. This drug is also reported to modulate an effector cell immune response through the activation of T and natural killer (NK) cells, inducing apoptosis directly on tumour cells. Currently available data indicate that Lenalidomide is active also in heavily pre-treated CLL patients with unfavourable prognostic factors. However, in order to optimize the therapeutic index of Lenalidomide treatment in CLL patients, it will be necessary to identify features of tumour cells that differ between responder and non responder patients. Hence, we reported results from a multicenter, phase II study designed in order to identify potential predictive factors correlating with response to Lenalidomide treatment in relapsed/refractory CLL. Marasca:CELGENE CORPORATION: Honoraria, Research Funding.

Effects of stocking density and sustained aerobic exercise on growth, energetics and welfare of rainbow trout

Two stocking densities, “low” (L, between ~19 and ~25kgm−3) and “high” (H, between ~75 and ~100kgm−3) were compared for effects on specific growth rate (SGR), feed conversion, energetics and welfare of rainbow trout reared at 14°C either in static water (S) or swimming in a gentle current of ~0.9 bodylengths s−1 (C). Trout (initial mass ~110g) were reared for 9weeks in circular tanks (volume 0.6m3), in triplicate of four conditions (LS, LC, HS, HC). Fish were fed ad-libitum daily; waste pellets were swirl-collected at the outflow to calculate feed intake. SGR was measured each three weeks for the last six weeks of the trial. The tanks functioned as intermittent-stopped flow respirometers, to permit metabolic rate to be measured as instantaneous oxygen uptake once per hour. Mean (±SD) SGR was significantly lower at H than L (1.51±0.03 vs 1.44±0.04% day−1, respectively, n=6) and lowest in HC. When compared over a similar interval of mass gain, H groups had approximately 25% higher metabolic rates than L, with the highest rates in the HC condition. As a result, fish in the H groups dissipated a greater amount of feed energy as metabolism and, across all groups, there was a direct negative relationship between the quantity of energy dissipated and their SGR. There was no evidence of a neuroendocrine stress response, plasma cortisol was around 1ngml−1 in all conditions. An acute crowding stress increased plasma cortisol to above 120ngml−1 in all groups, but C groups recovered to control levels within 8h whereas S groups required 20h. Respirometry on individuals revealed that H fish had approximately 14% higher metabolic rates than L fish, indicating that increased metabolic rate in rearing tanks was in part physiological. The H groups had approximately 15% lower critical swimming speeds than the L groups which, together with their raised metabolic rate, indicated a physiological impairment. Thus, high density reduced SGR by raising energy dissipation, at least partially as a physiological response by the fish, although there was no evidence of an endocrine stress response. The only beneficial effect of C was in recovery from acute stress.

Integration or Predictability? A Further Specification of the Functional Role of Gamma Oscillations in Language Comprehension

Gamma-band neuronal synchronization during sentence-level language comprehension has previously been linked with semantic unification. Here, we attempt to further narrow down the functional significance of gamma during language comprehension, by distinguishing between two aspects of semantic unification: successful integration of word meaning into the sentence context, and prediction of upcoming words. We computed event-related potentials (ERPs) and frequency band-specific electroencephalographic (EEG) power changes while participants read sentences that contained a critical word (CW) that was (1) both semantically congruent and predictable (high cloze, HC), (2) semantically congruent but unpredictable (low cloze, LC), or (3) semantically incongruent (and therefore also unpredictable; semantic violation, SV). The ERP analysis showed the expected parametric N400 modulation (HC < LC < SV). The time-frequency analysis showed qualitatively different results. In the gamma-frequency range, we observed a power increase in response to the CW in the HC condition, but not in the LC and the SV conditions. Additionally, in the theta frequency range we observed a power increase in the SV condition only. Our data provide evidence that gamma power increases are related to the predictability of an upcoming word based on the preceding sentence context, rather than to the integration of the incoming word’s semantics into the preceding context. Further, our theta band data are compatible with the notion that theta band synchronization in sentence comprehension might be related to the detection of an error in the language input.

Influence of Treatment for Disruptive Behavior Disorders on Adrenal and Gonadal Hormones in Youth

The study examined whether psychosocial intervention for children diagnosed with a disruptive behavior disorder (DBD; n = 84) changed concentrations of cortisol and testosterone across a 3-year follow-up when compared to a matched, nonclinical, healthy comparison (HC; n = 69) group. Boys and girls (6–11 years) with a DBD were randomly assigned to one of two arms of a multimethod intervention. Hierarchical linear modeling revealed that children undergoing psychosocial intervention for a DBD experienced a significant decline in diurnal cortisol change over time (p < .05) when compared to the HC condition. Boys with a DBD diagnosis had significantly lower mean cortisol concentrations prior to treatment (p < .05) and showed a significantly steeper increase in mean cortisol over time (p < .05) when compared to HC boys. Treatment effects for diurnal cortisol change were replicated in the boys-only analysis. No treatment effects were noted for testosterone in either analysis.

Effect of Meal Composition and Exercise Training on Glucose and Insulin Excursions Over 12 h

Increasing meal frequency may help weight loss and regulation of blood glucose levels. However, the impact of meal composition and exercise training on glucose or insulin levels throughout the day is unclear. PURPOSE: Thus the purpose of this study was twofold: 1. To compare the differences in the glucose and insulin excursions in response to frequent high carbohydrate meals vs. high protein meals, and 2. To establish the effect of short-term exercise training on the glucose and insulin response to frequent high carbohydrate meals. METHODS: Ten obese men and women were studied on two occasions, where they consumed 6 meals every 2 h (250 kcal/meal). On one occasion they consumed a high carbohydrate meal (HC)-14% protein, 21% fat, and 65% carbohydrate-1500 kcal), and on the second occasion they consumed a high protein meal (HP)- 45% protein, 35% carbohydrate, 20% fat-1500 kcal) in a randomized order. In addition, all subjects completed 15 days of exercise training (1 h/day, 70% VO2 max) and then repeated the HC study day. Blood glucose and insulin levels were measured every 10 min for 12 h. RESULTS: The HC meal resulted in a higher glucose level (total area under the curve-AUC) over the 12 hr than the HP meal (395±18 vs. 364±10 mmol/L*min, respectively, P<0.05). Likewise insulin AUC was greater during the HC condition (192,966±19,918 pmol/L*min) than the HP condition (162,519±22,772 pmol/L*min, P<0.05). Dividing the meals into 2 h increments did not reveal any pattern of response in glucose or insulin concentrations across the day. Exercise training did not significantly alter the total AUC over 12 h for either the glucose or insulin concentrations. CONCLUSIONS: In obese individuals, a higher protein meal given frequently results in lower glucose and insulin concentrations over the course of 12 h as compared to a higher carbohydrate meal. Short term exercise training had no effect on the glucose or insulin excursions over the course of a day. Supported by NIH R21DK084467-01

Duathlon Performance Unaltered by Short-Term Changes in Dietary Fat and Carbohydrates

This study investigated the effects of short-term dietary changes on metabolism and duathlon performance. Eleven men underwent a high-fat (HF; >65% fat from energy) or a high-carbohydrate (CHO; HC) diet (>60% CHO from energy). Energy intake was individualized, and commercially available foods were prepared and packaged for each participant 48 hr before they completed a laboratory-based duathlon (5-km run, 30 km cycling, and 10-km run). Blood samples were obtained before, immediately after, and 1 and 2 hr after the duathlon for determination of glucose, insulin, and glucagon. Oxygen consumption, ratings of perceived exertion (RPE), and respiratory-exchange ratio were assessed, and fat and CHO oxidation were estimated before, during, and after the duathlon. Dietary records indicated a significant difference in fat content ingested before the duathlons (p < .05). Time to complete the duathlon did not differ between the HC- and the HF-diet trials. CHO-oxidation rate was higher during the HC-diet trial than during the HF-diet trial (p = .006). Fat-oxidation rates were higher in the HF-diet trial than in the HC-diet trial (p = .001). No differences in RPE were found between dietary trials. Blood glucose concentration was higher immediately after the duathlon in the HC-diet trial than in the HF-diet trial and remained higher 1 and 2 hr after the duathlon (p < .05). Duathlon performance was not altered by short-term changes in dietary fat or CHO composition despite higher blood glucose concentrations under the HC condition.

Growth and Photosynthetic Responses of One C3and Two C4Chenopodiaceae Plants to Three CO2Concentration Conditions

Growth and photosynthetic responses of one <TEX>$C_3$</TEX> and two <TEX>$C_4$</TEX> plants in the family Chenopodiaceae in three <TEX>$CO_2$</TEX> concentration <TEX>$([CO_2])$</TEX> conditions-low (about <TEX>$243{\mu}mol\;mol^{-1}$</TEX>, LC), present (about 378, PC), and high (about 465, HC)-were investigated in open top chambers. The relative growth rate (RGR) and net assimilation rate in the <TEX>$C_3$</TEX> plant, Chenopodium album, increased with increasing <TEX>$[CO_2]$</TEX>, though the RGR was not enhanced significantly in the HC condition. The leaf area ratio and leaf weight ratio of the <TEX>$C_3$</TEX> plant drastically decreased with increasing <TEX>$[CO_2]$</TEX>, suggesting that the <TEX>$C_3$</TEX> plant invests more biomass to leaves in lower <TEX>$[CO_2]$</TEX> conditions. The two <TEX>$C_4$</TEX> plants, Atriplex glauca and A. lentiformis, showed relatively small changes in those growth parameters. These photosynthetic-pathway-dependent responses suggest that growth patterns of <TEX>$C_3$</TEX> and <TEX>$C_4$</TEX> plants have been altered by past increases in atmospheric <TEX>$[CO_2]$</TEX> but that there will be relatively little further alteration in the future high-<TEX>$CO_2$</TEX> world.

Role of taurine in osmoregulation during endurance exercise.

Taurine is released by contracting muscles, but its actual role remains unspecified. In this study, we investigated whether the exercise-stimulated release of taurine from muscle into the plasma regulates the modification of osmolality induced by intramuscular osmolyte production. Six subjects performed 90 min of cycling exercise (at 70% maximum power output) on two occasions, with (HC) or without (DC) fluid intake. Taurine content was determined in plasma, blood cells and urine before and after the endurance events, together with plasma osmolality. Plasma osmolality increased by 4% in the DC experiment ( P<0.01), but remained stable in the HC condition. The exercise also induced changes in the mean (SD) plasma taurine content to a greater degree in HC [+63 (26)%] than in DC [+33 (18)%; P<0.05], supporting the hypothesis that taurine is released into the plasma via an osmoregulatory process. However, the higher plasma taurine content in HC was not related to changes in renal taurine. In addition, the increase of taurine in plasma was not related to its release from blood cells since their taurine concentration increased by 70% both in HC [429 (77) to 680 (82) microM; P=0.003] and in DC [451 (57) to 731 (34) microM; P<0.001]. The lack of correlation between plasma volume modification and the mass ratio of taurine would exclude a major role for taurine exchange in plasma volume regulation. Sodium ( R=0.967, P<0.001), chloride ( R=0.917, P<0.001) and osmolality ( R=0.924, P<0.001) seem to be the main regulators of plasma volume changes during exercise. In conclusion, changes in the plasma taurine content during endurance exercise is related to an osmoregulatory process, but this alone does not control plasma volume changes.

Different CO2 levels during incubation interact with hatching time and ascites susceptibility in two broiler lines selected for different growth rate

Embryos from ascites sensitive (AS) and resistant lines (AR) were subjected during the third week of incubation to a high CO2 (0.4%) (HC) or normal CO2 level of 0.2% (NC) in the incubators. The effect on embryonic and hatching parameters and growth, ascites sensitivity and related physiological parameters was followed. At NC conditions AR embryos hatch earlier than AS ones but this difference completely disappeared under HC condition, since hatching time of the AS line was reduced. Moreover, AS embryos showed slightly lower T4 and T3 levels than AR embryos. Embryos of both lines incubated at HC had higher plasma T3 concentrations than those incubated at NC. Chickens that had been incubated at HC level showed less ascites mortality than those incubated at NC. RV/TV ratios were higher in NC birds compared with HC ones. It is concluded that different ventilation levels during incubation interact with total incubation time and thereby influence ascites susceptibility.

危機状況からの脱出行動における同調性と固着性に関する実験的研究

The purpose of the present study was to investigate the effects of “fear” and “credibility of others' behavior (subject's belief that someone knows the correct escape route)” on conformity and fixation of the subject's choice of an escape route. The experiment was conducted in a 2 (fear=FE vs. non-fear=NF)×2 (high credibility=HC vs. low credibility=LC) factorial design. In the early stage of the experiment, the degree of conformity was greater in the FE condition than in the NF condition. However, in the later stage, conformity gradually fell down in the FE condition but not in the NF condition. The increase rate in conformity was higher in the HC condition than in the LC condition. The degree of fixation on a given route was higher in the FE condition than in the NF condition.