Top PDF Ice Slurry and Cold Drink Reduces Exercise Induced Physiological Strain in the Heat

Ice Slurry and Cold Drink Reduces Exercise Induced Physiological Strain in the Heat

Ice Slurry and Cold Drink Reduces Exercise Induced Physiological Strain in the Heat

Based on enthalpy of fusion, Siegel et al. (47) hypothesized that ingestion of ice slurry before exercise would create a “heat sink”, which would allow more metabolic heat to be transferred in the conversion of ice to water, resulting in a lowered core temperature. Therefore, he conducted a random and counterbalanced study with two trials. The 10 males that participated in the study either ingested 7.5 g/kg of ice slurry (-1 - 0°C) or cold water (4°C) in a 30-minute period before running to exhaustion in a hot and humid environment (34.0°C and 54.9% relative humidity). Time to exhaustion, pre and post-exercise core temperatures, skin temperature, heart rate, sweat rate, perceived exertion, and thermal sensation was measured. Time to exhaustion was greater in the ice slurry trial versus the cold water (50.2 minutes vs 40.7 minutes) and perceived exertion as well as thermal sensation was lower in the ice slurry trial versus the cold water trial. After ice slurry ingestion and before exercise core temperature was reduced by 0.66°C relative to only 0.25°C after cold water ingestion. Thus, it was concluded that an ice slurry beverage was an effective pre-cooling modality compared to water. However, both drinks were not the same temperature so it can’t be concluded that ice slurry acted as a greater heat sink compared to the same temperature liquid.
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Experimental Study on Ice Slurry  Refrigeration System with Pre Cooling  Heat Exchanger

Experimental Study on Ice Slurry Refrigeration System with Pre Cooling Heat Exchanger

In the present study, the ice slurry refrigeration system with pre-cooling heat exchanger (ISSH) is studied experimentally to achieve the system performance, ice crystal formation time and the tem- perature of ice crystal formation. The operating parameters considered in this paper include the concentration of salt solution, suction pressure, discharge pressure and Energy Efficiency Ratio (EER). The result shows that the temperature of critical time of ice crystal formation decreases with the increasing concentration of salt solution and that the ice crystal formation time increases with the increasing concentration of salt solution. In the same concentration of salt solution, the ice crystal formation temperature of ISSH is lower than that of basic ice slurry refrigeration sys- tem (BISS), and the ice crystal formation time of ISSH is shorter than that of BISS. On the whole, the EER of ice slurry refrigeration system with pre-cooling heat exchanger is higher than that of basic ice slurry refrigeration system.
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Changes in Intragastric Temperature Reflect Changes in Heat Stress Following Tepid Fluid Ingestion But Not Ice Slurry Ingestion

Changes in Intragastric Temperature Reflect Changes in Heat Stress Following Tepid Fluid Ingestion But Not Ice Slurry Ingestion

Abstract This study examined the effects of fluid and ice slurry ingestion on the relationship between intragastric temperature and rectal temperature in humans during physical activity. The purpose was to identify a technique to quantify changes in heat stress in situations when temperature probes are not feasible and when time constraints do not allow for a period long enough for an indigestible temperature capsule to reach the lower gastrointestinal tract. Eight moderately trained male runners inserted a rectal probe and ingested a telemetric capsule before randomized, crossover, pre-exercise ingestion of 7.5 mL?kg -1 ?BM -1 tepid fluid (22 ˚ C) or ice slurry (21 ˚ C). Beverage ingestion was followed by a self-paced endurance running time trial. Average intragastric temperature was significantly lower than average rectal temperature across the run following both fluid (37.9 ¡ 0.4 ˚ C vs. 38.4 ¡ 0.2 ˚ C; p50.003) and ice slurry ingestion (37.2 ¡ 0.9 vs. 38.3 ¡ 0.2; p50.009). However, a strong relationship was observed between measurements following fluid (r50.89) but not ice slurry (r50.18). The average bias ¡ limits of agreement during the run was 0.46 ¡ 0.50 following fluid and 1.09 ¡ 1.68 following ice slurry ingestion, which improved to 0.06 ¡ 0.76 and 0.65 ¡ 1.42, respectively when analyzed as delta scores. Intragastric temperature appears to not be a valid measure of absolute core body temperature at baseline or during exercise following either fluid or ice slurry ingestion. However, the relative changes in intragastric temperature during endurance exercise appears to be a strong indicator of systemic heat stress during exercise following ingestion of fluid at 22 ˚ C, but not ice slurry at 21 ˚ C.
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Industrial heat stress : Using ice slurry ingestion as a practical approach to reducing heat strain in workers

Industrial heat stress : Using ice slurry ingestion as a practical approach to reducing heat strain in workers

Working in hot and humid environments can challenge the body’s thermolytic processes. Physiologically, the metabolic heat created by work and the ability to dissipate this generated heat is dependent on the thermal and partial pressure gradients between the body and the environment. In order to protect personnel working under such extreme conditions, heat stress indices have been developed. Invariably, some of these indices account for metabolic activity, ambient conditions, clothing, and/or the physiological responses associated with these changes (Brake and Bates 2002; ISO 2004; ISO 2004; ISO 1989; McArdle, Dunham et al. 1947; Moran, Shitzer et al. 1998). Despite the development of several heat stress indices, the WBGT has generally been accepted by industry and is widely used, even though the shortcomings of the index have been well documented (McNeill and Parsons 1999; Mutchler, Malzahn et al. 1976; Taylor 2006). Acknowledging these criticisms, Study 1 of this thesis aimed at identifying a single heat stress index which could best predict the heat load experienced by personnel working in the LNG industry both on-and offshore. The results from that study revealed that the WBGT was in fact not the best index to predict heat strain among LNG workers and that the P 4 SR is the preferred index. A significant correlation between measured responses
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Heat Transfer in an Ice-Slurry Flow

Heat Transfer in an Ice-Slurry Flow

There are, however, also some problems associated with ice-slurry systems. Two are particu- larly important: stratification and the unification of ice particles after a certain time. Stratification is the separation of two phases due to a buoyancy force. In ice slurries the ice is lighter than the rest of the solution, and so in the case of improper mixing we get two phases, which causes an increase in the pressure drop or even stoppage of the flow and the whole cooling system. To prevent this it is neces- sary to use an ice slurry a short time after its produc- tion and to install mixing elements in the ice-slurry storage and pipes, which can have a negative im- pact on the whole system.
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CFD SIMULATION OF ICE SLURRY FLOW IN VERTICAL PIPE

CFD SIMULATION OF ICE SLURRY FLOW IN VERTICAL PIPE

Due to the energy, environmental and safety challenges, demand of secondary loop refrigeration systems increases. Refrigerant in the secondary loop system can be a single phase or two-phase fluids, however two-phase mixture as the secondary loop refrigerant take advantage of the high latent heat during the phase change process and less pumping power than single phase fluids. In the two-phase secondary loop refrigerants, ice slurry and carbon dioxide shows the huge potential. Ice slurry has a high energy storage density, higher heat transfer coefficient and it also reduces the system size (storage tank and pipelines), however carbon dioxide has some disadvantages as two-phase secondary loop refrigerant [1]. Due to these attractive features, the ice slurry gains much attention as a secondary loop refrigerant over other single phase fluids. Ice slurry can be defined as a dispersed ice particles in carrier liquid (either water or binary solution of water and freezing point depressant). In the ice slurry the size of the ice particles may vary from 0.1 mm to 1.0 mm, however smaller particle size more beneficial [2]. For the particular applications, the initial size of the particle, concentration and configuration of carrier liquid may vary.
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Alleviating Heat Strain During Exercise: Hand Cooling and Thermoregulation

Alleviating Heat Strain During Exercise: Hand Cooling and Thermoregulation

Flouris and Schlader [149] suggested that thermal perception is an important mediator of behavioural thermoregulation that integrates with RPE in its role as the predominant controller of exercise intensity. We found that RPE and thermal perception were improved by cooling during fixed-intensity exercise and is a key finding from our analysis. Prior to increases in core temperature, self-selected intensity of exercise is likely mediated by thermal perception and its influence on RPE, whereas when core and skin temperature are elevated cardiovascular strain is a key RPE input [149]. Studies included in the present meta-analysis used neck cooling, ice slurry and fluid ingestion. Cooling the neck during heat exposure elicits feelings of thermal comfort at rest [81], a finding extended to 2 [167, 236] of 3 neck cooling during exercise studies. We found an unclear effect for one study [168]; the reason for this is unknown as the neck cooling collar was the same and participants and environmental conditions were similar in all three investigations. The study, however, was designed to investigate time to exhaustion and final core temperature was >39 °C, therefore cardiovascular strain might have been the key RPE mediator rather than thermal perception, however, it is worth noting that RPE was similar between conditions. There was also a clear beneficial effect of ice slurry ingestion on thermal perception in one study [233] but not in another [164]. These differences might be attributed to the study design, specifically, a beneficial effect of set-planned [233] rather than ad libitum [164] ingestion of slurry. Lee et al. [235] reported similar between-trial responses for thermal perception (400 ml of 10°C fluid versus 37 °C fluid ingested at 15 min intervals), although the mean ambient temperature of 25.3 °C combined with an intensity of 50% V̇O 2max was among the least
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Alleviating Heat Strain During Exercise: Hand Cooling and Thermoregulation

Alleviating Heat Strain During Exercise: Hand Cooling and Thermoregulation

2.5.2 Perceptual responses Flouris and Schlader [149] suggested that thermal perception is an important mediator of behavioural thermoregulation that integrates with RPE in its role as the predominant controller of exercise intensity. We found that RPE and thermal perception were improved by cooling during fixed-intensity exercise and is a key finding from our analysis. Prior to increases in core temperature, self-selected intensity of exercise is likely mediated by thermal perception and its influence on RPE, whereas when core and skin temperature are elevated cardiovascular strain is a key RPE input [149]. Studies included in the present meta-analysis used neck cooling, ice slurry and fluid ingestion. Cooling the neck during heat exposure elicits feelings of thermal comfort at rest [81], a finding extended to 2 [167, 236] of 3 neck cooling during exercise studies. We found an unclear effect for one study [168]; the reason for this is unknown as the neck cooling collar was the same and participants and environmental conditions were similar in all three investigations. The study, however, was designed to investigate time to exhaustion and final core temperature was >39 °C, therefore cardiovascular strain might have been the key RPE mediator rather than thermal perception, however, it is worth noting that RPE was similar between conditions. There was also a clear beneficial effect of ice slurry ingestion on thermal perception in one study [233] but not in another [164]. These differences might be attributed to the study design, specifically, a beneficial effect of set-planned [233] rather than ad libitum [164] ingestion of slurry. Lee et al. [235] reported similar between-trial responses for thermal perception (400 ml of 10°C fluid versus 37 °C fluid ingested at 15 min intervals), although the mean ambient temperature of 25.3 °C combined with an intensity of 50% V̇O 2max was among the least
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Ice ingestion with a long rest interval increases the endurance exercise capacity and reduces the core temperature in the heat

Ice ingestion with a long rest interval increases the endurance exercise capacity and reduces the core temperature in the heat

The timing in which ice is ingested may be import- ant for optimizing its effects. In most previous studies, subjects ingested ice over a 30-min period at a stan- dardized rate that ranged from 5 min. However, Onit- suka et al. [14] found that when participants reminded at rest, their rectal temperature (Tre) kept on decreas- ing for approximately 20 min after following the end of 7.5 g kg body mass (BM) −1 ice slurry ingestion. Similarly, Naito and Ogaki [15] reported that intermit- tent ice ingestion at 1.25 g kgBM −1 every 5 min for 30 min continued to decrease the Tre until approxi- mately 20 min after the end of ingestion; in their study, the Tre was reduced by 0.56 ± 0.20 °C compared to ingestion as a single bolus. Previous studies have suggested that the greater the magnitude by which the core temperature is reduced, the greater the perform- ance benefit [7]. Thus, we thought that intermittent ice ingestion would be an even more effective strategy if subsequent exercise was started after a lower Tre had been achieved. It is possible that a novel pre- cooling strategy with a long rest interval (LRI; 20 min) after ice ingestion may reduce the pre-exercise core temperature and improve the endurance cycling cap- acity compared with a traditional strategy involving only a short rest interval (SRI; 5 min).
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Administration of Tomato Juice or Aqueous Components of Tomato Reduces Fatigue  Induced by Acute Treadmill Exercise

Administration of Tomato Juice or Aqueous Components of Tomato Reduces Fatigue Induced by Acute Treadmill Exercise

extent than water. Carbohydrates in the form of muscle and liver glycogen and blood glucose are the primary source of energy during exercise; one reason for declines in exercise performance is the depletion of muscle glycogen levels. Furthermore, hypoglycemia can occur during prolonged exercise, which can contribute to fati- gue by limiting the supply of energy to working muscles. This can be countered by carbohydrate supplementa- tion, which effectively improves endurance [9] [10]. In contrast, OAs had no effect of indicators of fatigue. Based on these findings, we speculate that EAAs or sugars are the components of tomato juice that are responsi- ble for the observed anti-fatigue effects. However, the amounts were much lower than those reported to reduce fatigue [9]-[12], giving rise to the possibility of synergistic effects or the contribution of other unidentified sub- stances.
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Sustainable solutions to mitigate occupational heat strain – an umbrella review of physiological effects and global health perspectives

Sustainable solutions to mitigate occupational heat strain – an umbrella review of physiological effects and global health perspectives

Timing and location of the interventions In terms of both mitigating physiological strain and im- proving performance, cooling before [ 66 , 80 , 89 , 90 , 92 , 93 ], as opposed to during [ 72 , 75 , 80 , 89 , 90 ], physical activity in the heat was found to be more effective (Fig. 3 ). This find- ing may be due to the types of cooling interventions avail- able before compared to during activity (e.g. whole-body cold water immersion was the most effective personal cool- ing intervention but cannot be employed during activity). This may also be because cooling interventions applied dur- ing exercise reduce the natural heat loss responses [ 156 ], whereas at rest, when cooling responses are not yet acti- vated and cannot be reduced, cooling interventions allow for the reduction of core temperature, resulting in an in- ternal heat sink [ 133 , 135 ]. It is also important to note that in most of the original investigations contributing to the systematic reviews, most exertional protocols lasted be- tween 1 and 2 h, and therefore activities of longer durations (such as an + 8 h work day), the internal heat sink effect may play a less significant role. Conversely, metabolic rates during occupational tasks are typically lower than those ob- served during athletic events [ 157 ], and therefore, the bene- ficial effects of precooling may be extended. Further, as the original studies informing these reviews were generally of an athletic context, clothing conditions differed consider- ably to real-world conditions (with less clothing generally being warn during athletics). However, it should be noted that precooling with ice slurries and cold water immersion has been found to be highly effective for short duration oc- cupational tasks requiring highly insulating PPE (e.g. fire- fighters, those wearing hazmat suits, etc.) [ 158 ].
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Physiological response to exercise in the Icelandic horse

Physiological response to exercise in the Icelandic horse

Figure 1. Comparison of tölt and trot in Paper II. Two horses on the track at the same time, one in trot (bay) and one in tölt (chestnut). 4.1.3 A simulated 100 m flying pace race (Paper III) A cross-over design was used in Paper III, with nine horses and two riders. On day one, five horses performed a simulated 100 m flying pace race (SPR) with rider 1 and the other four horses performed with rider 2. On day 5 the SPR was performed again, with the riders changed over. The exercise test was preceded by a 10 min warm-up, 5 min in walking and 5 min in tölt and trot in circles of different sizes in both directions (clockwise and counterclockwise). A true 100 m flying pace race is performed outdoors, individually on a straight track, and riders have two attempts with a few minutes of rest in between to get an approved (correct gait) pace run. The SPR was performed outdoors on a 400 m straight gravel riding track (Figure 2) and consisted of two runs, of which at least 100 m was in flying pace at full speed according to rules of FEIF (2012b). The horses were ridden (individually), in any gait the rider wished for the first 49 m (preparation period) but paced when crossing the 50 m line, i.e. “with flying start” (FEIF, 2012b) and then paced in racing speed for the timed 100 m (over the finishing line), and finally slowed down during 25 to 50 m (in total approximately 150-200 m run). The horses were walked for 5 min between the two pace runs. The horses were followed for 30 min recovery period. The horses were mounted (with rider and tack) during warm-up, exercise test and
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Bubble and Heat Transfer Phenomena in Viscous Slurry Bubble Column

Bubble and Heat Transfer Phenomena in Viscous Slurry Bubble Column

For the SBCR design, the understanding on the mixing among gas, liquid and particles, individual phase hol- dup and heat and mass transfer in the column are certainly essential. In addition, the flow behavior of gas phase is known to act a pivotal role in determining the heat transfer coefficient, since the gas bubbles, which exist as a dispersed phase, flow stochastically and randomly in the viscous slurry medium which is composed of solvent with particles [4]-[6]. Gas holdup is directly affected by gas velocity and particle concentration and is generally found to decrease with an increase of particle concentration in a SBCR [7]-[9]. With the addition of particles in bubble column, there will be an increase in the apparent viscosity of suspension [10] [11]. However, the charac- teristics of the heat transfer in the column have been estimated mainly by local heat transfer coefficients. In gen- eral, the local heat transfer coefficient has significant influence on bubbles which passed the surface of the probe. These bubbles could split with addition of particles in a column.
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DEVELOPMENT OF A PERCEPTUAL HYPERTHERMIA INDEX TO EVALUATE HEAT STRAIN DURING TREADMILL EXERCISE. Michael Gallagher, Jr.

DEVELOPMENT OF A PERCEPTUAL HYPERTHERMIA INDEX TO EVALUATE HEAT STRAIN DURING TREADMILL EXERCISE. Michael Gallagher, Jr.

Maughan et al. 42 summarizes in their review that performance on physical and mental tasks are significantly reduced by heat stress and dehydration. This response is due to the additional stress imposed on the cardiovascular system that may be a detriment to the central nervous system. Cheung 14 described a fundamental problem with previous research that assessed brain activity during hyperthermia. They noted that few studies tracked the effect of thermal stress on cognitive and task performance impairments in the presence of concomitant changes in physiological and/or perceptual thermal strain. As part of their training, the Australian Defense Forces have been exposed to “debilitating” tropical environments that negatively impacts physiological performance. Hocking et al. 28 observed that in addition to these physiological detriments, thermal strain did not impact cognition of those military personnel. It was found that even through subjects experienced increased cardiovascular strain, the psychometric test batteries showed no significant performance detriments yet there was a marked difference in the electrical responses of the brain when thermally strained. Cheung 14 suggests that while cognitive impairment may be sensitive to thermal stress, it may also be negated or minimized by other compensatory mechanisms that limit performance degradation. This may help explain conflicting results among studies examining hyperthermia (and the resulting hypohydration) on cognitive function.
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Pre-Exercise ORS drink and muscle efficiency by bicycle ergography

Pre-Exercise ORS drink and muscle efficiency by bicycle ergography

During exercise, consuming beverages containing electrolytes and carbohydrates can provide benefits over water alone. After exercise, the aim is to restore any fluid and electrolyte deficit. The hypohydration that occurs during exercise is usually described as hyper osmotic hypovolemia. Depending upon the metabolic rate, environmental conditions and clothing worn, exercise can bring on significant elevations in body temperatures. Besides containing water, sweat contains electrolytes that are lost which, when not suitably replaced, dehydration and hyponatremia can increase and can cause a negative impact on the individual’s exercise performance. Sweat electrolyte losses depend on the total sweat losses and sweat electrolyte concentrations. Sweat sodium concentration averages ~35 mEq/hr (range 10–70 mEq/hr). Sweat concentrations of potassium averages 5 mEq/ L (range 3–15 mEq/L) , calcium averages 1 mEq/L (range 0.3–2 mEq/L), magnesium average 0.8 mEq/L (range 0.2–1.5 mEq/L), and chloride averages 30 mEq/L (range 5–60 mEq/L). Sweat glands reabsorb sodium and chloride, but the ability to reabsorb these electrolytes does not increase proportionally with the sweat rate. 12
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Determination of Contents of Cold Drink -Class 12 Chemistry Project

Determination of Contents of Cold Drink -Class 12 Chemistry Project

PURPOSE In recent days, soft drink brands were put into various questions regarding their purity. News flashed that they contain harmful pesticide, which arouse many interest in knowing its contents because I have been drinking them for years. I wanted to confirm that whether the charge imposed on these brands are true or not.

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Physiological response to exercise in the Icelandic horse

Physiological response to exercise in the Icelandic horse

The peak haematocrit levels reached in Papers I, III and IV (see section 5.5.1) were low compared with those measured after high intensity exercise in the field at similar time points in e.g. Standardbred trotters (mean ± SE: 60 ± 1 %; Jansson & Dahlborn, 1999) and Thoroughbreds (mean: 63 ± 1 %; Evans et al., 1993). It has been shown that haematocrit values are numerically highest during maximum exercise (at fatigue) and start to decline immediately as the intensity of exercise decreases (Bayly et al., 2006). Therefore blood samples have to be collected during intensive exercise to evaluate true maximum haematocrit levels in the Icelandic horse. It is known that maximum haematocrit in Standardbred and Thoroughbred racehorses can reach 60-68% post high intensity exercise (Persson, 1983; Snow et al., 1983b; Evans et al., 1993) and 60% in Quarterhorses (Reynolds et al., 1993). Most of the increase in Hct during exercise is related to splenic release, but there is also an effect of substantial fluid shifts out of plasma during exercise (Persson, 1967; Carlson, 1983). Maximum reference values of haematocrit for different horse breeds are not easy to find in the literature, apart from for Thoroughbreds, Standardbreds and Quarterhorses. However, the blood circulatory capacity of different horse breeds has been related to spleen and heart weight, with racing breeds (Thoroughbreds and Standardbreds) having significantly (P<0.01) greater relative spleen size than other breeds (stock types, Arabian and draft types) and significantly (P<0.01) greater relative heart size than both stock and draft types (Kline & Foreman, 1991). This could indicate that horse breeds other than racing types, e.g. the Icelandic horse, might also have lower maximum Hct, but this needs further study.
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PREVENTATIVE EXERCISE PROGRESSION FOR HAMSTRING STRAIN

PREVENTATIVE EXERCISE PROGRESSION FOR HAMSTRING STRAIN

Plyometric exercise is based on the principle of utilizing the muscle’s stretch reflex with stores energy through its eccentric phase of contraction. If utilized quickly, the energy stored can produce more force output during the concentric event. This brief moment between the two phases is the amortization phase. When performing plyometric exercise it is essential to perform a rapid eccentric phase to decrease the amortization time. They should be progressed systematically for proper overload; typically low intensity with high volume up to high intensity with low volume. It is also important to warm up properly in a plyometric fashion, which can be incorporated in the dynamic warm up. An appropriate plyometric warm up for these particular exercises include:
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The Effects of Low Intensity Endurance  Activity on Various Physiological  Parameters and Exercise Induced Oxidative Stress in Dogs

The Effects of Low Intensity Endurance Activity on Various Physiological Parameters and Exercise Induced Oxidative Stress in Dogs

Following an endurance sled dog race changes in serum biochemistry were opposite compared to those seen following low intensity endurance exercise, i.e., decreased albumin, total protein and sodium, and increased phosphorus. The only similarity between the findings in sled dogs and our study dogs was increased chloride and decreased potassium. Elevations in HCT, total protein, albumin, sodium, chloride and blood urea nitrogen can be explained in part by dehydration and inter compartmental fluid shifts causing hemoconcentration [1] [3]. Sympathetic induced splenic contraction occurs in agility dogs and Greyhounds and is thought to partially ex- plain elevations in hematocrit post exercise [1] [29]. However, our increases were mild compared to those ob- served in Greyhounds. Thus it would appear that both of these processes occurred in the study dogs with com- plete recovery 20 hours post-exercise.
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Heat-killed Tsukamurella inchonensis reduces lipopolysaccharide-induced inflammatory responses in activated murine peritoneal macrophages

Heat-killed Tsukamurella inchonensis reduces lipopolysaccharide-induced inflammatory responses in activated murine peritoneal macrophages

and likely contributes to the long-term cognitive and neuroanatomical sequelae of sepsis, such as be- havioural deficits and neuronal loss (Semmler et al. 2007). The reports of Riedemann et al. (2003) and Gennari and Alexander (1995) indicate that limit- ing the biological activity of IL-6 improves survival. In the present study, we have shown that T. in- chonensis inhibited LPS-induced TNF-α in a dose- dependent manner. This inhibition did not have effect on macrophage viability. The slight increase in TNF-α levels seen in the low dose group is likely due to non-specific effects or macrophage activa- tion, which has been shown to occur in isolated peritoneal macrophages (Howard et al. 2009). Dexamethasone impedes the production of TNF by endotoxin-stimulated macrophages, but pre- treatment of macrophages with dexamethasone prior to endotoxin stimulation was essential for effective inhibition (Morrison 1987). Tumor ne- crosis factor-α, one of the most important pro- inflammatory cytokines, is secreted mainly from activated monocyte/macrophages in response to diverse extracellular stimuli, and plays a ma- jor role in inflammatory diseases such as septic shock and rheumatoid arthritis (Nagahira et al. 2001). Tumor necrosis factor is intrinsically py- rogenic, similar to IL-1. It also has the ability to induce IL-1 with its consequent spectrum of po- tent biological activities (Dinarello et al. 1986). Lipopolysaccharide is known to be a strong stim- ulator of TNF-α production (Ohnishi et al. 1994). Lipopolysaccharide-stimulated TNF-α production in monocyte/macrophages is positively regulated at the transcriptional and translational levels (Beutler 1990). Interferon-γ has been shown to augment TNF biosynthesis (Beutler 1990), apparently acting to up-regulate both the transcriptional and post- transcriptional responses to LPS. Current evidence indicates that macrophages play an important role in the pathogenesis of inflammatory responses through their ability to produce proinflammatory cytokines (Delgado et al. 1999). Proinflammatory cytokines, which include TNF-α and IL-6, are gen- erated in tissues infected by microbial pathogens as well as in tissues subjected to generalised trauma such as ischaemia/reperfusion injury. Production of inflammatory mediators serves a necessary func- tion by facilitating wound healing, partly by recruit- ing various immune cell populations.
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