The purpose of this study was to examine factors influencing susceptibility to upper respiratory tract infections (URTI) in 18-35-year-old men and women engaged in endurance-based physical activity during the winter months. Eighty individuals (46 males, 34 females) provided resting blood and saliva samples for determination of markers of systemic immunity. Weekly training and illness logs were kept for the following 4 months. Thirty subjects did not experience an URTI episode and 24 subjects experienced 3 or more weeks of URTI symptoms. These illness-prone subjects had higher training loads and had ∼2.5-fold higher interleukin (IL)-4 and IL-10 production by antigen-stimulated whole blood culture than the illness-free subjects. Illness-prone subjects also had significantly lower saliva S-IgA secretion rate and higher plasma IgM (but not IgA or IgG) concentration than the illness-free subjects. There were no differences in circulating numbers of leukocyte subtypes or lymphocyte subsets between the illness-prone and illness-free subjects. The production of IL-10 was positively correlated and the S-IgA secretion rate was negatively correlated with the number of weeks with infection symptoms. It is concluded that high IL-10 production in response to antigen challenge and low S-IgA secretion are risk factors for development of URTI in physically active individuals.

The purpose of this study was to examine the effects of a probiotic supplement during 4 mo of spring training in men and women engaged in endurance-based physical activities on incidence of upper respiratory tract infections (URTI) and mucosal immune markers. Sixty-six highly active individuals were randomized to probiotic (n = 33) or placebo (n = 33) groups and, under double-blind procedures, received probiotic (PRO: Lactobacillus salivarius, 2 × 1010 bacterium colony-forming units) or placebo (PLA) daily for 16 wk. Resting blood and saliva samples were collected at baseline and after 8 and 16 wk. Weekly training and illness logs were kept. Fifty-four subjects completed the study (n = 27 PRO, n = 27 PLA). The proportion of subjects on PRO who experienced 1 or more wk with URTI symptoms was not different from that of those on PLA (PRO .58, PLA .59; p = .947). The number of URTI episodes was similar in the 2 groups (PRO 1.6 ± 0.3, PLA 1.4 ± 0.3; p = .710). Severity and duration of symptoms were not significantly different between treatments. Blood leukocyte, neutrophil, monocyte, and lymphocyte counts; saliva IgA; and lysozyme concentrations did not change over the course of the study and were not different on PRO compared with PLA. Regular ingestion of L. salivarius does not appear to be beneficial in reducing the frequency of URTI in an athletic cohort and does not affect blood leukocyte counts or levels of salivary antimicrobial proteins during a spring period of training and competition.

BackgroundMost sub-Saharan African countries struggle to make safe surgery accessible to rural populations due to a shortage of qualified surgeons and the unlikelihood of retaining them in district hospitals. In 2002, Zambia introduced a new cadre of non-physician clinicians (NPCs), medical licentiates (MLs), trained initially to the level of a higher diploma and from 2013 up to a BSc degree. MLs have advanced clinical skills, including training in elective and emergency surgery, designed as a sustainable response to the surgical needs of rural populations.MethodsThis qualitative study aimed to describe the role, contributions and challenges surgically active MLs have experienced. Based on 43 interviewees, it includes the perspective of MLs, their district hospital colleagues—medical officers (MOs), nurses and managers; and surgeon-supervisors and national stakeholders.ResultsIn Zambia, MLs play a crucial role in delivering surgical services at the district level, providing emergency surgery and often increasing the range of elective surgical cases that would otherwise not be available for rural dwellers. They work hand in hand with MOs, often giving them informal surgical training and reducing the need for hospitals to refer surgical cases. However, MLs often face professional recognition problems and tensions around relationships with MOs that impact their ability to utilise their surgical skills.ConclusionsThe paper provides new evidence concerning the benefits of ‘task shifting’ and identifies challenges that need to be addressed if MLs are to be a sustainable response to the surgical needs of rural populations in Zambia. Policy lessons for other countries in the region that also use NPCs to deliver essential surgery include the need for career paths and opportunities, professional recognition, and suitable employment options for this important cadre of healthcare professionals.

The angiotensin-converting enzyme (ACE) I/D and α-actinin 3 (ACTN3) R/X polymorphisms have been suggested to influence variations in skeletal muscle function. This study investigated the association between ACE I/D and ACTN3 R/X polymorphisms and muscle strength and contractile properties in young UK Caucasian men. Measurements of the knee extensor muscles were taken from 79 recreationally active but non-strength-trained males on two occasions. Isometric knee extensor strength was measured using a conventional strength-testing chair. Maximal twitches were electrically evoked by percutaneous stimulation to assess time-topeak tension, half-relaxation time and peak rate of force development. The torque-velocity relationship was measured at four angular velocities (0, 30, 90 and 240 deg s −1 ) using isokinetic dynamometry, and the relative torque at high velocity was calculated (torque at 240 deg sas a percentage of that at 30 deg s −1 ). The ACE I/D and ACTN3 R/X polymorphisms were genotyped from whole blood by polymerase chain reaction. Serum ACE activity was assayed from serum using automated spectrophotometry. Physical characteristics were independent of either genotype. Absolute and relative high-velocity torque were not influenced by ACE or ACTN3 genotypes. Isometric strength and the time course of a maximal twitch were independent of ACE and ACTN3 genotypes. Serum ACE activity was significantly dependent on ACE genotype (P < 0.001), but was not associated with any measure of functional or contractile properties. Knee extensor functional and contractile properties, including high-velocity strength, were not influenced by ACE and ACTN3 polymorphisms in a cohort of UK Caucasian males. Any influence of these individual polymorphisms on human skeletal muscle does not appear to be of sufficient magnitude to influence function in free-living UK Caucasian men. Genetic factors are thought to determine 20-80% of the variation in a number of traits important to athletic performance (MacArthur & North, 2007), for example the relative proportion of fast-and slowtwitch skeletal muscle fibres (Simoneau & Bouchard, 1995; ∼45% due to inherited factors). The annual publication of the human gene map for performance and health-related fitness phenotypes (Rankinen et al. 2006) lists more than 150 genes or genetic regions associated with athletic performance and physical fitness traits. The angiotensin-converting enzyme (ACE) I/D polymorphism (Williams et al. 2005) and α-actinin 3 (ACTN3) R577X polymorphism (Mills et al. 2001) have recently been identified as potential influences contributing to variations in skeletal muscle composition, function and performance.The ACE gene has been the most extensively studied gene in the area of human performance phenotypes. A functional polymorphism of the ACE gene is defined as the presence (insertion, I allele) or absence (deletion, D allele) of a 287-amino-acid base pair Alu repeat sequence within intron 16 of the ACE gene on chromosome 17 (Rigat et al. 1990). The polymorphism results in th...