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Erythropoietin ( EPO) rapidly decreases on return to sea level ( SL) after chronic altitude exposure. Acute hypoxia may provide an additional stimulus to prevent the decline in EPO. Proinflammatory cytokines, interleukin-6 ( IL-6), and tumor necrosis factor alpha ( TNFα) have been shown to inhibit EPO production. Optimal normobaric hypoxic exposure has not been established; therefore, investigation of methods eliciting the greatest response in EPO to limit physiological stress is required. Eight men (age 27 ± 4 years, body mass 77.5 ± 9.0 kg, height 179 ± 6 cm) performed four passive exposures to different normobaric hypoxic severities [FiO2: 0.209 ( SL), FiO2: ~0.135 (3600 m), FiO2: ~0.125 (4200 m) and FiO2: ~0.115 (4800 m)] in a hypoxic chamber for 2 h. Venous blood was drawn pre-exposure and then at 1, 2, 4, 6, and 8 h to determine EPO concentration ([ EPO]), IL-6, and TNFα. During 4200 and 4800 m, [ EPO] increased from 5.9 ± 1.5 to 8.1 ± 1.5 mU/ mL ( P = 0.009) and 6.0 ± 1.4 to 8.9 ± 2.0 mU/ mL ( P = 0.037), respectively, with [ EPO] increase peaking at 4 h (2 h post-exposure). There were no differences in IL-6 or TNFα during or post-exposure. Increased [ EPO] was found 2 h post hypoxic exposure as result of 2 h of normobaric hypoxia ≥4200 m. There was no dose-response relationship in [ EPO] between simulated hypoxia severities. [ABSTRACT FROM AUTHOR]

Ecological specialization to restricted diet niches is driven by obligate, and often maternally inherited, symbionts in many arthropod lineages. These heritable symbionts typically form evolutionarily stable associations with arthropods that can last for millions of years. Ticks were recently found to harbour such an obligate symbiont, Coxiella- LE, that synthesizes B vitamins and cofactors not obtained in sufficient quantities from blood diet. In this study, the examination of 81 tick species shows that some Coxiella- LE symbioses are evolutionarily stable with an ancient acquisition followed by codiversification as observed in ticks belonging to the Rhipicephalus genus. However, many other Coxiella- LE symbioses are characterized by low evolutionary stability with frequent host shifts and extinction events. Further examination revealed the presence of nine other genera of maternally inherited bacteria in ticks. Although these nine symbionts were primarily thought to be facultative, their distribution among tick species rather suggests that at least four may have independently replaced Coxiella- LE and likely represent alternative obligate symbionts. Phylogenetic evidence otherwise indicates that cocladogenesis is globally rare in these symbioses as most originate via horizontal transfer of an existing symbiont between unrelated tick species. As a result, the structure of these symbiont communities is not fixed and stable across the tick phylogeny. Most importantly, the symbiont communities commonly reach high levels of diversity with up to six unrelated maternally inherited bacteria coexisting within host species. We further conjecture that interactions among coexisting symbionts are pivotal drivers of community structure both among and within tick species. [ABSTRACT FROM AUTHOR]

Twelve males completed three incremental, discontinuous treadmill tests in the heat [31.9(1.0) °C, 61.9(8.9)%] to determine speed at two fixed blood lactate concentrations (2 and 3.5 mmol/L), running economy ( RE), and maximum oxygen uptake ( [ABSTRACT FROM AUTHOR]

The current study assessed sex differences in thermoregulatory and physiological adaptation to short-term ( STHA) and long-term heat acclimation ( LTHA). Sixteen (eight males; eight females) participants performed three running heat tolerance tests ( RHTT), preceding HA ( RHTT1), following 5 days HA ( RHTT2) and 10 days HA ( RHTT3). The RHTT involved 30-min running (9 km/h, 2% gradient) in 40 °C, 40% relative humidity. Following STHA, resting rectal temperature ( Trrest) (males: −0.24 ± 0.16 °C, P ≤ 0.001; females: −0.02 ± 0.08 °C, P = 0.597), peak rectal temperature ( Trpeak) (males: −0.39 ± 0.36 °C, P ≤ 0.001; females −0.07 ± 0.18 °C, P = 0.504), and peak heart rate (males: −14 ± 12 beats/min, P ≤ 0.001; females: −5 ± 3 beats/min, P = 0.164) reduced in males, but not females. Following STHA, sweat rate relative to body surface area ( SRBSA) increased (428 ± 269 g/h/m2, P = 0.029) in females, but not males (−11 ± 286 g/h/m2, P = 0.029). Following LTHA, Trrest (males: −0.04 ± 0.15 °C, P = 0.459; females: −0.22 ± 0.12 °C, P ≤ 0.01) and Trpeak (males: −0.05 ± 0.26 °C, P = 0.590; females: −0.41 ± 0.24 °C, P ≤ 0.01) reduced in females, but not males. Following LTHA, SRBSA increased in males (308 ± 346 g/h/m2, P = 0.029), but not females (44 ± 373 g/h/m2, P = 0.733). Males and females responded to STHA; however, females required LTHA to establish thermoregulatory and cardiovascular stability. HA protocols should be designed to target sex differences in thermoregulation for optimal adaptation. [ABSTRACT FROM AUTHOR]

Thermotolerance, to which heat shock protein-72 ( Hsp72) contributes, is an acquired state achieved following heat acclimation ( HA), eliciting cellular adaption and protection against thermal stress. Optimal HA methods achieving the greatest heat shock response ( HSR) are equivocal; therefore, investigation of methods provoking the greatest sustained HSR is required to optimize cellular adaptation. Twenty-four males performed short-term HA ( STHA; five sessions) and long-term HA ( LTHA; STHA plus further five sessions) utilizing fixed-intensity ( FIXED; workload = 50% [ABSTRACT FROM AUTHOR]

A large part of international economics research is devoted to the theory of Purchasing Power Parity (PPP). There have been numerous attempts by economists over the years to devise an accurate, reliable and convenient measure for this theory – the most famous of these being the “Big Mac index” compiled by The Economist. In the spirit of the “Big Mac index”, this paper introduces another alternative measure of PPP here, using the prices of postage stamps for international mail delivery, that is just as, if not more, attractive as any other current measure. [ABSTRACT FROM AUTHOR]

Hematological and plasma biochemical values of wild grasscutters were evaluated to determine their potential to transmit zoonotic pathogens. Three 5-mL blood samples were collected from each of 1000 grasscutters caught in the wild for hematology, biochemical, and parasitological tests. Hematological and biochemical values were compared with those from captive-reared grasscutters. There are significantly ( P < 0.05) higher lymphocyte, eosinophil, and basophil values for wild grasscutters compared to those that are captive reared. Parasitological examination revealed a 15% prevalence of blood protozoa in the wild grasscutters. Blood pathogens encountered were Trypanosoma sp. (66.7%) and Plasmodium sp. (33.3%), with 20.7% mixed infection. Sex does not significantly ( P > 0.05) affect blood protozoa infection, while season does. We therefore concluded that wild grasscutters serve as efficient reservoir hosts for agents of African trypanosomiasis and malaria in the tropical humid rainforest region of Nigeria. [ABSTRACT FROM AUTHOR]

The incidence of cysticercosis due to Taenia saginata in both local and exotic breeds of cattle slaughtered for meat in southeastern Nigeria between November 1999 and April 2002 is reported. The examination of various organs of 25,800 cattle in 10 major abattoirs of this region showed that 6750 (26.2%) were infected with Cysticercus (C.) bovis. The prevalence rates varied from one abattoir to another while the rates of cysticercosis in local and exotic breeds varied significantly ( P > 0.05). Sixty percent of all the infected animals had cysts. The tongue, cardiac, and masseter muscles were the main predilection sites of the cysts. Out of 11,720 male cattle, examined, 3215 (27.4%) had cysts of C. bovis while 160 (13.6%) of the 1180 female animals investigated were infected. There was an inverse relationship between the ages of the animals and prevalence of infection with C. bovis ( r=−0.8743, P < 0.05). Monthly occurrence of the cysts in the animals revealed an upsurge of infected animals during the dry season. The epidemiology and epizootiology of Taenia saginata and C. bovis in relation to the veterinary service agencies and public health planners in southeastern Nigeria are highlighted. [ABSTRACT FROM AUTHOR]

The article focuses on science curriculum that was established in primary schools and junior secondary schools in Papua New Guinea. Science education in the country was strongly influenced by foreign countries including Australia alongside expatriate staff from England, the Philippines and the United Nations. Educators in the country admit that they are uncertain of the future of the subject because of growing pressure to improve the curriculum. On top of that, they are required to provide students skills and knowledge.

SIRT1 is an NAD + -dependent deacetylase that functions in a variety of cells and tissues to mitigate age-associated diseases. However, it remains unknown if SIRT1 also acts to prevent pathological changes that accrue in motor neurons during aging and amyotrophic lateral sclerosis (ALS). In this study, we show that SIRT1 expression decreases in the spinal cord of wild-type mice during normal aging. Using mouse models either overexpressing or lacking SIRT1 in motor neurons, we found that SIRT1 slows age-related degeneration of motor neurons' presynaptic sites at neuromuscular junctions (NMJs). Transcriptional analysis of spinal cord shows an overlap of greater than 90% when comparing alterations during normal aging with changes during ALS, revealing a substantial upregulation in immune and inflammatory response genes and a downregulation of synaptic transcripts. In addition, overexpressing SIRT1 in motor neurons delays progression to end-stage disease in high copy SOD1 G93A mice. Thus, our findings suggest that there are parallels between ALS and aging, and interventions to impede aging may also slow the progression of this devastating disease., (© 2018 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.)

Motor function deteriorates with advancing age, increasing the risk of adverse health outcomes. While it is well established that skeletal muscles and neuromuscular junctions (NMJs) degenerate with increasing age, the effect of aging on α-motor neurons and their innervating synaptic inputs remains largely unknown. In this study, we examined the soma of α-motor neurons and innervating synaptic inputs in the spinal cord of aged rhesus monkeys and mice, two species with vastly different lifespans. We found that, in both species, α-motor neurons retain their soma size despite an accumulation of large amounts of cellular waste or lipofuscin. Interestingly, the lipofuscin profile varied considerably, indicating that α-motor neurons age at different rates. Although the rate of aging varies, α-motor neurons do not atrophy in old age. In fact, there is no difference in the number of motor axons populating ventral roots in old mice compared to adult mice. Moreover, the transcripts and proteins associated with α-motor neurons do not decrease in the spinal cord of old mice. However, in aged rhesus monkeys and mice, there were fewer cholinergic and glutamatergic synaptic inputs directly abutting α-motor neurons, evidence that aging causes α-motor neurons to shed synaptic inputs. Thus, the loss of synaptic inputs may contribute to age-related dysfunction of α-motor neurons. These findings broaden our understanding of the degeneration of the somatic motor system that precipitates motor dysfunction with advancing age., (© 2018 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.)

Background: hypoxia has been shown to increase glucose uptake in skeletal muscle using the contraction-stimulated pathway, independent of the actions of insulin. Yet, the same stress has also been linked with causing insulin resistance and hyperglycaemia. The aim of this study was to examine the effects of acute hypoxia with and without exercise on insulin sensitivity (S(I)(2*) in individuals with type 2 diabetes., Methods: eight type 2 diabetic patients completed 60 min of the following: (1) normoxic rest; (2) hypoxic rest [O(2) = 14.6 (0.4)%]; (3) normoxic exercise and (4) hypoxic exercise [O(2) = 14.6 (0.4)%]. Exercise trials were set at 90% of lactate threshold. Each condition was followed by a labelled intravenous glucose tolerance test to provide estimations of insulin sensitivity (S(I)(2*) and β-cell function., Results: Two-compartmental analysis showed that insulin sensitivity (S(I)(2*) was higher following hypoxic rest compared with normoxic rest (p = 0.047). Insulin sensitivity (S(I)(2*) was also higher following hypoxic exercise [4.37 (0.48) × 10(-4) /min (µU/mL)] compared with normoxic exercise [3.24 (0.51) × 10(-4) /min (µU/mL)] (p = 0.048). Acute insulin response to glucose was reduced following hypoxic rest versus normoxic rest (p = 0.014)., Conclusions: this study demonstrated that (1) hypoxic-induced improvements in glucose tolerance in the 4 h following exposure can be attributed to improvements in peripheral insulin sensitivity (S( I)(2*) and (2) exercise and hypoxia have an additive effect on insulin sensitivity (S(I)(2*) in type 2 diabetic patients. Acute hypoxia may therefore improve short-term glycaemic control in individuals with type 2 diabetes. The application of these findings in the clinic will require further investigation., (2010 John Wiley & Sons, Ltd.)

The purpose of this study was to test the hypothesis that intermittent supramaximal running would be negatively affected when performed in a hot humid environment. Twelve physically active, male volunteers took part in this study. The exercise model was performed under three environmental trial conditions, randomly assigned and separated by 1 week. This included performing: (a) a standardized warm-up in the cool environment and a repeated sprint test in the cool environment (CC); (b) a standardized warm-up in the cool environment and a repeated sprint test in a hot, humid environment (CH); and (c) a standardized warm-up in a hot, humid environment and a repeated sprint test in a hot, humid environment (HH). The repeated sprint test involved 20 s runs, each at increasing-intensity, with 100s passive recovery between successive sprints. Capillary blood samples were taken post-warm-up and at 1, 3 and 6 min post-repeated sprint test for the determination of plasma lactate, ammonia and glucose concentrations and the percentage change in plasma volume. Rectal, aural and mean skin temperature were measured continuously throughout each trial condition. Sweat loss was estimated from the change in body mass. Sweat loss was significantly greater in the HH trial than in the CH trial and in the CH trial than in the CC trial (P < 0.0001). Performance was significantly better in the CC trial than in the CH and HH trials (CC vs. CH and HH: 151 +/- 4 vs. 144 +/- 5 and 140 +/- 5 s, respectively, P = 0.02). For the post-exercise data, significant differences were found between the CC and the CH and HH trials in rectal (P = 0.007), aural (P < 0.001) and mean skin temperatures (P < 0.001). No significant differences were found in post-repeated sprint test lactate and ammonia concentrations, or in plasma volume among trial conditions, but glucose concentrations were higher in the CH and HH trials than in the CC trial (P = 0.005). No significant differences were found in performance, body temperature or any blood measurement between the CH and HH trials. Intermittent supramaximal running performance was detrimentally affected by a hot, humid environment, resulting in performance being significantly less in the CH and HH trials than in the CC trial.