Effects of Normobaric and Hypobaric Hypoxia on Mitochondrial Related Gene Expression

Environmental stimuli such as temperature and hypoxia can influence cellular signaling in the skeletal muscle. Previously we have reported no changes in gene expression related to mitochondrial development with acute exposure to normobaric hypoxia. However, exposure to hypobaric hypoxia may elicit different physiological responses. Purpose: To determine the response of skeletal muscle mitochondrial related gene expression after 4 h of exposure to normobaric normoxia (NN), normobaric hypoxia (NH), and hypobaric hypoxia (HH) after exercise. Methods: Recreationally trained participants (8 male, 7 female) each completed three trials of 1-h cycling at 70% of Wmax. Following exercise, participants sat in an environmentally controlled chamber for a 4-h recovery period in NN (975 m), NH (4,420 m), or HH (4,420 m) environmental conditions. Muscle biopsies were taken from the vastus lateralis pre-exercise and after a 4-h environmental exposure period. Samples were analyzed using qRT-PCR to assess gene expression related to mitochondrial development. Results: There were no differences in mRNA between trials or times in PGC-1α (p = 0.804), GABPA (p = 0.650), ERRα (p = 0.956), or NRF1 (0.563). TFAM mRNA increased in NH from pre-exercise to post-exercise (p = 0.036) and NH was higher compared to NN (p = 0.011) and but not HH (p = 0.053). Conclusion: These data indicate that gene expression related to mitochondrial development is only marginally affected (TFAM) by the type of hypoxic environment after a 4-h treatment despite differences in arterial oxygen saturation

Higher Muscle Tissue Oxygenation When Exposed to Hypobaric Hypoxia Than Normobaric Hypoxia

There has been recent debate on the potential difference in physiological response between exposure to simulated altitude (normobaric hypoxia) and terrestrial altitude (hypobaric hypoxia). Purpose: To determine the difference in the physiological response to normobaric and hypobaric hypoxia during exercise. Methods: Eight recreationally active subjects (27 ± 5 y old, 73.1 ± 7.4 kg body weight, 170.6 ± 6.7 cm height, and 19.3 ± 9.2 % body fat) completed incremental cycling exercise to volitional fatigue in three separate environments: normobaric normoxia (NN; 350 m), normobaric hypoxia (NH; simulated 3094 m), and hypobaric hypoxia (HH; 3094 m). Heart rate, blood oxygen saturation, and muscle tissue oxygenation were measured at rest and continuously throughout the exercise trials. Results: Blood oxygen saturation (SpO2) was ~10% higher in NN compared to the two hypoxic conditions (p \u3c 0.001) at rest and all exercise stages, with no difference between NH and HH (p \u3e 0.05). Heart rate was higher at rest in HH (98 ± 13 bpm) compared to NN (83 ± 15 bpm, p = 0.011) and NH (84 ± 14 bpm, p = 0.001) which persisted until 165 watts at which point no difference was observed (p \u3e 0.05). Muscle tissue oxygenation was 17% higher in HH compared to NN and 19% higher than NH throughout exposure (p \u3c 0.05). Conclusion: This data indicates that the hypoxic stress resulting from normobaric and hypobaric hypoxia are not the sameand that hypobaric hypoxia may not result in hypoxia at the level of the tissue

Acute High Intensity Anaerobic Training and Rhabdomyolysis Risk

International Journal of Exercise Science 8(1) : 65-74, 2015. The current popularity of high intensity anaerobic training has caused concerns over the safety and prevalence of conditions such as rhabdomyolysis; thus it is important to understand the possible risks of participating in this type of activity. The purpose of this study was to determine the magnitude of muscle damage associated with a single high intensity anaerobic training session, and the relationship of this response to markers of fitness. Fifteen recreationally trained male participants (age 22.9 ± 4.3 y, mass 87.3 ± 15.6 kg, body fat 16.8 ± 6.4%, VO2 peak 50.1 ± 7.2 ml · kg-1 · min-1 ) completed a single anaerobic training session consisting of high intensity plyometrics and calisthenics. Prior to the exercise session, participants completed a maximal aerobic capacity test, body composition analysis, and a military physical fitness test (1 min push-ups, 54 ± 14; 1 min sit-ups, 45 ± 11; 1.5 mile run, 12:17 ± 0.067 min). Serum creatine kinase (CK) was measured prior to and 48 h following the exercise session. CK at 48 h (126.3 ± 68.9 U· L-1) did not reach the limits indicating rhabdomyolysis (~881-1479 U/L) but was elevated above resting (CK resting 90.5 ± 53.4). VO2 peak (L · m-1) had a positive correlation with CK levels (r = .51; p \u3c 0.05) but body mass or any other indicator of fitness did not correlate. An increase in serum CK levels occurred, but did not reach levels of rhabdomyolysis, suggesting that a single high intensity exercise session is safe for healthy individuals who exercise regularly

Exercise-Induced Interleukin-6 and Metabolic Responses in Hot, Temperate, and Cold Conditions

The purpose of this study was to determine the effects of exercise in hot, cold, and temperate environments on plasma interleukin-6 (IL-6). Eleven recreationally trained males (age = 25 ± 4 years, height = 178 ± 5 cm, weight = 79.4 ± 13.5 kg, body fat = 14.7 ± 3.6%, VO2 peak = 54.6 ± 11.5 ml kg-1 min-1) performed a 1 hr cycling bout in hot (33 °C), cold (7 °C), and temperate (20 °C) environments at 60% of Wmax followed by 3 hr of supine recovery in temperate conditions. Expired gases were measured every 15 min during exercise and once every hour during recovery. Heart rate was continuously measured throughout the trials. Blood samples were obtained from the antecubital vein pre-exercise, immediately post-exercise, and 3 hr post-exercise. Blood samples were analyzed for plasma concentrations of IL-6 using a commercial ELISA kit. Plasma IL-6 concentrations were significantly higher immediately post-exercise (14.8 ± 1.6 pg ml-1, p = 0.008) and 3 hr post-exercise (14.8 ± 0.9 pg ml-1, p = 0.018) compared to pre-exercise (11.4 ± 2.4 pg ml-1), across all trials. There were no differences in plasma IL-6 concentrations (p = 0.207) between temperature conditions.Oxygen consumption and heart rate were higher and respiratory exchange ratio was lower in the hot compared to other conditions (p \u3c 0.05). These data indicate that the temperature in which exercise occurs does not affect acute plasma IL-6 response despite differences in metabolic state

Effects of acute hypoglycemia on working memory and language processing in adults with and without type 1 diabetes

OBJECTIVE To examine the effects of hypoglycemia on language processing in adults with and without type 1 diabetes. RESEARCH DESIGN AND METHODS Forty adults were studied (20 with type 1 diabetes and 20 healthy volunteers) using a hyperinsulinemic glucose clamp to lower blood glucose to 2.5 mmol/L (45 mg/dL) (for 60 min, or to maintain blood glucose at 4.5 mmol/L (81 mg/dL) (euglycemia), on separate occasions. Language tests were applied to assess the effects of hypoglycemia on the relationship between working memory and language (reading span), grammatical decoding (self-paced reading), and grammatical encoding (subject-verb agreement). RESULTS Hypoglycemia caused a significant deterioration in reading span (P < 0.001; eta(2) = 0.37; Cohen d = 0.65) and a fall in correct responses (P = 0.005; eta(2) = 0.19; Cohen d = 0.41). On the self-paced reading test, the reading time for the first sentence fragment increased during hypoglycemia (P = 0.039; eta(2) = 0.11; Cohen d = 0.25). For the reading of the next fragment, hypoglycemia affected the healthy volunteer groupmore than the adults with type 1 diabetes (P = 0.03; eta(2) = 0.12; Cohen d = 0.25). However, hypoglycemia did not significantly affect the number of errors in sentence comprehension or the time taken to answer questions. Hypoglycemia caused a deterioration of subject-verb agreement (correct responses: P = 0.011; eta(2) = 0.159; Cohen d = 0.31). CONCLUSIONS Hypoglycemia caused a significant deterioration in reading span and in the accuracy of subject-verb agreement, both of which are practical aspects of language involved in its everyday use. Language processing is therefore impaired during moderate hypoglycemia

Critical analysis of the utility of initial pleural aspiration in the diagnosis and management of suspected malignant pleural effusion

INTRODUCTION:Current guidelines recommend an initial pleural aspiration in the investigation and management of suspected malignant pleural effusions (MPEs) with the aim of establishing a diagnosis, identifying non-expansile lung (NEL) and, at times, providing a therapeutic procedure. A wealth of research has been published since the guidelines suggesting that results and outcomes from an aspiration may not always provide sufficient information to guide management. It is important to establish the validity of these findings in a 'real world' population. METHODS:A retrospective analysis was conducted of all patients who underwent pleural fluid (PF) sampling, in a single centre, over 3 years to determine the utility of the initial aspiration. RESULTS:A diagnosis of MPE was confirmed in 230/998 (23%) cases, a further 95/998 (9.5%) were presumed to represent MPE. Transudative biochemistry was found in 3% of cases of confirmed MPE. Positive PF cytology was only sufficient to guide management in 45/140 (32%) cases. Evidence of pleural thickening on CT was associated with both negative cytology (&#x3C7;2 1df=26.27, p&lt;0.001) and insufficient samples (&#x3C7;2 1df=10.39, p=0.001). In NEL 44.4% of patients did not require further procedures after pleurodesis compared with 72.7% of those with expansile lung (&#x3C7;2 1df=5.49, p=0.019). In patients who required a combined diagnostic and therapeutic aspiration 106/113 (93.8%) required further pleural procedures. CONCLUSIONS:An initial pleural aspiration does not achieve either definitive diagnosis or therapy in the majority of patients. A new pathway prioritising symptom management while reducing procedures should be considered

The dominant Anopheles vectors of human malaria in Africa, Europe and the Middle East: occurrence data, distribution maps and bionomic précis

<p>Abstract</p> <p>Background</p> <p>This is the second in a series of three articles documenting the geographical distribution of 41 dominant vector species (DVS) of human malaria. The first paper addressed the DVS of the Americas and the third will consider those of the Asian Pacific Region. Here, the DVS of Africa, Europe and the Middle East are discussed. The continent of Africa experiences the bulk of the global malaria burden due in part to the presence of the <it>An. gambiae </it>complex. <it>Anopheles gambiae </it>is one of four DVS within the <it>An. gambiae </it>complex, the others being <it>An. arabiensis </it>and the coastal <it>An. merus </it>and <it>An. melas</it>. There are a further three, highly anthropophilic DVS in Africa, <it>An. funestus</it>, <it>An. moucheti </it>and <it>An. nili</it>. Conversely, across Europe and the Middle East, malaria transmission is low and frequently absent, despite the presence of six DVS. To help control malaria in Africa and the Middle East, or to identify the risk of its re-emergence in Europe, the contemporary distribution and bionomics of the relevant DVS are needed.</p> <p>Results</p> <p>A contemporary database of occurrence data, compiled from the formal literature and other relevant resources, resulted in the collation of information for seven DVS from 44 countries in Africa containing 4234 geo-referenced, independent sites. In Europe and the Middle East, six DVS were identified from 2784 geo-referenced sites across 49 countries. These occurrence data were combined with expert opinion ranges and a suite of environmental and climatic variables of relevance to anopheline ecology to produce predictive distribution maps using the Boosted Regression Tree (BRT) method.</p> <p>Conclusions</p> <p>The predicted geographic extent for the following DVS (or species/suspected species complex*) is provided for Africa: <it>Anopheles </it>(<it>Cellia</it>) <it>arabiensis</it>, <it>An. </it>(<it>Cel.</it>) <it>funestus*</it>, <it>An. </it>(<it>Cel.</it>) <it>gambiae</it>, <it>An. </it>(<it>Cel.</it>) <it>melas</it>, <it>An. </it>(<it>Cel.</it>) <it>merus</it>, <it>An. </it>(<it>Cel.</it>) <it>moucheti </it>and <it>An. </it>(<it>Cel.</it>) <it>nili*</it>, and in the European and Middle Eastern Region: <it>An. </it>(<it>Anopheles</it>) <it>atroparvus</it>, <it>An. </it>(<it>Ano.</it>) <it>labranchiae</it>, <it>An. </it>(<it>Ano.</it>) <it>messeae</it>, <it>An. </it>(<it>Ano.</it>) <it>sacharovi</it>, <it>An. </it>(<it>Cel.</it>) <it>sergentii </it>and <it>An. </it>(<it>Cel.</it>) <it>superpictus*</it>. These maps are presented alongside a bionomics summary for each species relevant to its control.</p

Effects of 7°C environmental temperature during a 3-week training period

Approximately three weeks is required for cold temperature acclimation to occur. However, the effects of cold temperature acclimation on fitness and performance remain unknown. Purpose: To determine the impact of cold environmental temperature on training adaptations, fitness measurements, and aerobic performance. Methods: Two groups of twelve inactive male subjects completed 1-hour of cycling in fourteen temperature acclimation trials of either a cold (7°C) or room temperature (20°C) environmental temperature. A performance trial and tolerance trial occurred pre- and post-acclimation. The performance trials assessed VO2peak and body composition. Skin and core temperature were recorded during the 1-hour tolerance trials. Tympanic temperature, heart rate, and power output were recorded during the acclimation trials. Results: No difference occurred in tympanic temperature or heart rate from start to end of the acclimation trials or between temperatures (p\u3e0.05). Power increased during the acclimation (p\u3c0.001) but was not different between temperatures (p=0.169). VO2peak increased and percent body fat decreased from pre-acclimation to post-acclimation performance trials (p\u3c0.001) but neither were different between temperature groups (p\u3e0.05). Core and skin temperature did not change between the tolerance trials or between temperature groups (p\u3e0.05). Heart rate decreased (p\u3c0.001) and sweat rate increased (p=0.050) between the tolerance trials but were not different between temperatures (p\u3e0.05). Conclusion: These data indicate that a three-week acclimation period increases markers of fitness and aerobic performance, but no difference occurs between temperatures. Training period length and fitness status of the subjects may impact results and should be further investigated in cold environmental temperatures