Skeletal Muscle Metabolism in Endurance Athletes with Near-Infrared Spectroscopy

. Purpose: To determine whether near-infrared spectroscopy (NIRS) measurements of muscle mitochondrial function could detect the expected differences between endurance-trained athletes (n = 8) and inactive subjects (n = 8). Methods: Muscle oxygen consumption (mV O 2 ) of the vastus lateralis was measured with continuous-wave NIRS using transient arterial occlusions. The recovery rate of mV O 2 after electrical stimulation was fit to an exponential curve, with the time constant (T c ) used as an index of mitochondrial capacity. Whole-body peak oxygen uptake was determined by indirect calorimetry during a continuous ramp protocol on a cycle ergometer. Results: Whole-body peak oxygen uptake values for endurance-trained and inactive controls were 73.5 T 9.1 and 33.7 T 5.9 mLIkg j1 Imin j1 , respectively (P G 0.001). The recovery rates of mV O 2 after exercise for endurance training were 18.4 T 3.2 and 18.8 T 2.5 s, whereas those for inactive controls were 32.4 T 5.2 and 34.9 T 5.9 s for the shallow and deep channels, respectively (P G 0.001 for comparison between groups). Resting mV O 2 was 0.52%Is j1 T 0.22%Is j1 for endurance athletes and 0.77%Is j1 T 0.82%Is j1 for inactive controls (P = 0.42). Conclusions: The recovery rates of mV O 2 after exercise in endurance athletes were almost twofold faster than inactive subjects measured with NIRS, consistent with previous studies using muscle biopsies and magnetic resonance spectroscopy. Our results support the use of NIRS measurements of the recovery of oxygen consumption to assess muscle oxidative capacity. Key Words: NIRS, MITOCHONDRIAL CAPACITY, ELECTRICAL STIMULATION, OXIDATIVE METABOLISM, ENDURANCE TRAINING, MAXIMAL OXYGEN UPTAKE, COMPETITIVE CYCLISTS O xidative metabolism is the primary method of energy production in skeletal muscle, and changes in oxidative muscle metabolism have been shown to be useful in understanding muscle function in both healthy and diseased conditions MATERIALS AND METHODS Subjects. Sixteen subjects (12 men and 4 women) were tested in this study. Subjects were selected to have either

The effects of activating a “baby brain” stereotype on pregnant women’s cognitive functioning

Throughout pregnancy and into the immediate postpartum period, women are generally perceived to be incompetent, stressed, and forgetful. However, the neuropsychological “baby brain” literature remains unclear and contradictory. Across two studies, we provide the first experimental tests of whether perceived cognitive impairment in pregnancy can be explained by stereotype threat theory, which proposes that awareness of negative stereotypes about one’s ingroup can harm performance. In Study 1 (N = 364), we tested stereotype threat effects in a 2 (stereotype threat versus no threat) × 3 (pregnant women versus new mothers versus never-pregnant female control) design. We observed a main effect of group on memory performance (pregnant women and new mothers performed worse than controls), but no other main or interactive effects. Study 2 (N = 409) aimed to extend these research questions with mathematics ability, memory, and attention as the dependent variables. Again, we found that a stereotype threat manipulation did not impair pregnant women and new mothers’ cognitive performance, nor was there any interactive effects. Groups also did not differ in their performance. We discuss these results in the context of stereotype threat mechanisms, calling into question whether a stereotype threat paradigm can be applied effectively to pregnancy-related stereotypes. This work has implications for the advancement of stereotype threat as a theory and contributes to the reappraisal of the utility of stereotype threat as a way of understanding how stereotypes affect performance

Muscle Oxygen Changes following Sprint Interval Cycling Training in Elite Field Hockey Players

This study examined the effects of Sprint Interval Cycling (SIT) on muscle oxygenation kinetics and performance during the 30-15 intermittent fitness test (IFT). Twenty-five women hockey players of Olympic standard were randomly selected into an experimental group (EXP) and a control group (CON). The EXP group performed six additional SIT sessions over six weeks in addition to their normal training program. To explore the potential training-induced change, EXP subjects additionally completed 5 x 30s maximal intensity cycle testing before and after training. During these tests near-infrared spectroscopy (NIRS) measured parameters; oxyhaemoglobin + oxymyoglobin (HbO2+ MbO2), tissue deoxyhaemoglobin + deoxymyoglobin (HHb+HMb), total tissue haemoglobin (tHb) and tissue oxygenation (TSI %) were taken. In the EXP group (5.34±0.14 to 5.50±0.14m.s-1) but not the CON group (pre = 5.37± 0.27 to 5.39±0.30m.s-1) significant changes were seen in the 30-15IFTperformance. EXP group also displayed significant post-training increases during the sprint cycling: ΔTSI (-7.59±0.91 to -12.16±2.70%); ΔHHb+HMb (35.68±6.67 to 69.44 ±26.48μM.cm); and ΔHbO2+ MbO2 (-74.29±13.82 to -109.36±22.61μM.cm). No significant differences were seen in ΔtHb (-45.81±15.23 to -42.93±16.24). NIRS is able to detect positive peripheral muscle oxygenation changes when used during a SIT protocol which has been shown to be an effective training modality within elite athletes

Cryptococcus: from environmental saprophyte to global pathogen.

Cryptococcosis is a globally distributed invasive fungal infection that is caused by species within the genus Cryptococcus which presents substantial therapeutic challenges. Although natural human-to-human transmission has never been observed, recent work has identified multiple virulence mechanisms that enable cryptococci to infect, disseminate within and ultimately kill their human host. In this Review, we describe these recent discoveries that illustrate the intricacy of host-pathogen interactions and reveal new details about the host immune responses that either help to protect against disease or increase host susceptibility. In addition, we discuss how this improved understanding of both the host and the pathogen informs potential new avenues for therapeutic development

Cryptococcal meningitis: epidemiology, immunology, diagnosis and therapy.

HIV-associated cryptococcal meningitis is by far the most common cause of adult meningitis in many areas of the world that have high HIV seroprevalence. In most areas in Sub-Saharan Africa, the incidence of cryptococcal meningitis is not decreasing despite availability of antiretroviral therapy, because of issues of adherence and retention in HIV care. In addition, cryptococcal meningitis in HIV-seronegative individuals is a substantial problem: the risk of cryptococcal infection is increased in transplant recipients and other individuals with defects in cell-mediated immunity, and cryptococcosis is also reported in the apparently immunocompetent. Despite therapy, mortality rates in these groups are high. Over the past 5 years, advances have been made in rapid point-of-care diagnosis and early detection of cryptococcal antigen in the blood. These advances have enabled development of screening and pre-emptive treatment strategies aimed at preventing the development of clinical infection in patients with late-stage HIV infection. Progress in optimizing antifungal combinations has been aided by evaluation of the clearance rate of infection by using serial quantitative cultures of cerebrospinal fluid (CSF). Measurement and management of raised CSF pressure, a common complication, is a vital component of care. In addition, we now better understand protective immune responses in HIV-associated cases, immunogenetic predisposition to infection, and the role of immune-mediated pathology in patients with non-HIV associated infection and in the context of HIV-associated immune reconstitution reactions

Pathways forward to a more inclusive future whilst honouring the past

Some cultures teach people to only look at the exceptional, we encourage more looking at the ordinary and the everyday and realizing how exceptional that is. We need everyday stories. Hearing stories from women who have been leaders in OLEs for many years and those who are participants, for example, Christy Smith in Chap. 25 who describes her pathway to be an outdoor woman, demonstrates the importance of maintaining women’s access to OLEs. Looking forward, there ought to be many more stories on Twitter, in the popular press, and academia. There is hope. Arlene, Kathy, Hope, Harriet Tubman, and so many women have embodied much of what we all strive for: enthusiasm, joy, perseverance, competence, integrity, and passion. Women and allies can continue to influence OLEs, and we can continue to learn about our history