The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell‐released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV‐associated functional activities. Finally, a checklist is provided with summaries of key points.

To determine whether low bone density and other risk factors for osteoporosis are associated with stress fractures in athletes. Case-control study. Institutional sports injury clinic with primary and secondary care. Twenty-five athletes (nineteen women) with scintigraphically confirmed stress fractures matched for sex, age, weight, height, and exercise history with 25 control athletes with no history of bone injury. Bone mineral density measured by dual-energy x-ray absorptiometry was significantly lower in athletes with fractures than in control athletes: In the spine, bone mineral density was 1.01 +/- 0.14 g/cm2 in athletes with fractures and 1.11 +/- 0.13 g/cm2 in control athletes (P = 0.02). In the femoral neck, it was 0.84 +/- 0.09 g/cm2 in athletes with fractures and 0.90 +/- 0.11 g/cm2 in control athletes (P = 0.005). It was also significantly lower in the Ward triangle (P = 0.01) and the greater trochanter (P = 0.01). Eight athletes with fractures and no control athletes had less than 90% of predicted age-related spine density (P = 0.01), and three athletes with fractures had bone mineral densities that were 2 SDs or more below this predicted level. More athletes with fractures than control athletes had current menstrual irregularity (amenorrhea or oligomenorrhea) (P less than 0.005). Fewer athletes with fractures were using oral contraceptives (P less than 0.05). Seven-day diet records indicated similar energy and nutrient intakes, except athletes with fractures had lower calcium intakes (697 +/- 242 mg/d compared with 832 +/- 309 mg/d; P = 0.02). Dairy product intake was lower in athletes with fractures since leaving high school (P less than 0.05). The incidence of a family history of osteoporosis was similar in both groups. In athletes with similar training habits, those with stress fractures are more likely to have lower bone density, lower dietary calcium intake, current menstrual irregularity, and lower oral contraceptive use.

Twenty specialist marathon runners and 23 specialist ultra-marathon runners underwent maximal exercise testing to determine the relative value of maximum oxygen consumption (VO2max), peak treadmill running velocity, running velocity at the lactate turnpoint, VO2 at 16 km h-1, % VO2max at 16 km h-1, and running time in other races, for predicting performance in races of 10-90 km. Race time at 10 or 21.1 km was the best predictor of performance at 42.2 km in specialist marathon runners and at 42.2 and 90 km in specialist ultra-marathon runners (r = 0.91-0.97). Peak treadmill running velocity was the best laboratory-measured predictor of performance (r = -0.88(-)-0.94) at all distances in ultra-marathon specialists and at all distances except 42.2 km in marathon specialists. Other predictive variables were running velocity at the lactate turnpoint (r = -0.80(-)-0.92); % VO2max at 16 km h-1 (r = 0.76-0.90) and VO2max (r = 0.55(-)-0.86). Peak blood lactate concentrations (r = 0.68-0.71) and VO2 at 16 km h-1 (r = 0.10-0.61) were less good predictors. These data indicate: (i) that in groups of trained long distance runners, the physiological factors that determine success in races of 10-90 km are the same; thus there may not be variables that predict success uniquely in either 10 km, marathon or ultra-marathon runners, and (ii) that peak treadmill running velocity is at least as good a predictor of running performance as is the lactate turnpoint. Factors that determine the peak treadmill running velocity are not known but are not likely to be related to maximum rates of muscle oxygen utilization.