Candidemic complications in patients with intravascular catheters colonized with Candida species: an indication for preemptive antifungal therapy?

BACKGROUND: The impact of Candida-colonized catheter tips in patients without candidemia is unclear. METHODS: A retrospective study of patients with tip cultures positive for Candida was conducted over an 8-year period, to determine the outcomes in patients with Candida cultured from an intravascular catheter tip in the absence of preceding Candida-positive blood cultures. The primary outcome measure was definite candidemia. Secondary outcomes included possible candidemia and in-hospital mortality. A possible candidemia was defined as clinical signs and symptoms of invasive candidiasis without explanation other than a candidemia, but with negative blood cultures. RESULTS: Sixty-eight cultures from 64 patients were included in the study. Definite candidemia developed in three cases (4%) and possible candidemia developed in five cases (7%). In-hospital mortality was significantly increased in patients with definite or possible candidemia (63% vs. 22%, p=0.028). Risk factors for the development of definite or possible candidemia were catheter time in situ >8 days (odds ratio (OR) 6.0, 95% confidence interval (CI) 1.1-32.9) and abdominal surgery (OR 6.0, 95% CI 1.1-32.4). CONCLUSIONS: Intravascular catheter tip colonization in patients without preceding blood cultures with Candida is associated with candidemia in from 4% of patients (definite candidemia) up to 12% of patients (definite and possible candidemia combined). Considering the adverse prognosis associated with delayed treatment of candidemia, preemptive treatment based on catheter tip cultures might outweigh the disadvantages of costs and side effects of antifungal therapy.

Ability of different physical activity monitors to detect movement during treadmill walking.

This study assessed the ability of four different activity monitors to discriminate changes in treadmill walking velocity. The relationships between walking velocity and bodily movement and between bodily movement and energy expenditure determined by indirect calorimetry (IC-EE or METs) were determined. Twenty-eight subjects walked at 3.2, 4.0, 4.8, 5.6, and 6.4 km/h (0 % grade) for 30 min on separate occasions. The Tritrac-R3D (TT), Computer Science & Applications, Inc. (CSA), and Mini-Logger (ML) activity monitors that measure bodily acceleration in one or three planes, and a Yamax Digiwalker-500 (YX) that records footsteps, were secured at the waistline of each subject. CSA monitors were also worn at the wrist and ankle. Walking velocity and bodily movement were significantly related (r = 0.89 to 0.93) for TT, CSA, ML, and YX. Importantly, changing each walking velocity produced significant changes in bodily movement that was detected by each monitor. Bodily movement and IC-EE were significantly related for TT, CSA, ML, and YX (r = 0.47 to 0.94). Compared to IC-EE, and at all walking speeds, EE was significantly overestimated by the TT, and EE was significantly underestimated by the YX. These results indicate that the activity monitors can differentiate bodily movement associated with walking at slow speeds better than they can estimate energy expenditure associated with walking at slow speeds.

Evaluation of methods to assess physical activity in free-living conditions.

PURPOSE: The purpose of this study was to compare different methods of measuring physical activity (PA) in women by the doubly labeled water method (DLW). METHODS: Thirteen subjects participated in a 7-d protocol during which total daily energy expenditure (TDEE) was measured with DLW. Body composition, basal metabolic rate (BMR), and peak oxygen consumption were also measured. Physical activity-related energy expenditure (PAEE) was then calculated by subtracting measured BMR and the estimated thermic effect of food from TDEE. Simultaneously, over the 7 d, PA was assessed via a 7-d Physical Activity Recall questionnaire (PAR), and subjects wore secured at the waist, a Tritrac-R3D (Madison, WI), a Computer Science Application Inc. activity monitor (CSA; Shalimar, FL), and a Yamax Digi Walker-500 (Tokyo, Japan). Pearson-product moment correlations were calculated to determine the relationships among the different methods for estimating PAEE. Paired t-tests with appropriate adjustments were used to compare the different methods with DLW-PAEE. RESULTS: There was no significant difference between PAEE determined from PAR and DLW. The differences between the two methods ranged from -633 to 280 kcal.d(-1). Compared with DLW, PAEE determined from CSA, Tritrac, and Yamax was significantly underestimated by 59% (-495 kcal.d(-1)), 35% (-320 kcal.d(-1)) and 59% (-497 kcal.d(-1)), respectively. VO2peak explained 43% of the variation in DLW-PAEE. CONCLUSION: Although the group average for PAR-PAEE agreed with DLW-PAEE, there were differences in the methods among the subjects. PAEE determined by Tritrac, CSA, and Yamax significantly underestimate free-living PAEE in women.

Creatine supplementation and swimming performance.

The purpose of this study was to determine if oral creatine (CR) ingestion, compared to a placebo (PL), would enable swimmers to maintain a higher swimming velocity across repeated interval sets over 2 weeks of supplementation. Fourteen female and 18 male university swimmers consumed a PL during a 2-week baseline period. Using a randomized, double-blind design, during the next 2 weeks subjects consumed either CR or PL. Swimming velocity was assessed twice weekly during 6 X 50-m swims and once weekly during 10 X 25-yd swims. There was no effect of CR on the 10 X 25-yd interval sets for men and women and no effect on the 6 X 50-m interval sets for women. In contrast, for men, CR significantly improved mean overall swimming velocity in the 6 X 50-m interval after 2 weeks of supplementation, whereas PL had no effect. Although ineffective in women, CR supplementation apparently enables men to maintain a faster mean overall swimming velocity during repeated swims each lasting about 30 s; however, CR was not effective for men in repeated swims each lasting about 10 - 15 s.

Evaluation of a commercial accelerometer (Tritrac-R3 D) to measure energy expenditure during ambulation.

This study evaluated the ability of a commercially available accelerometer (Tritrac-R3 D) to measure energy expenditure in 16 subjects at rest (pre- and post-exercise) and during three different intensities of steady-state exercise (40-70% of peak oxygen consumption [VO2peak]) while ambulating on a treadmill (no grade). Oxygen consumption and the respiratory exchange ratio from indirect calorimetry and the vector magnitude of triaxial accelerations were used to estimate energy expenditure using the manufacturers' equations. There was a significant relationship between indirect calorimetry-derived energy expenditure and the energy expenditure derived from the accelerometer (r=0.96). Using analysis of variance, there was no difference in the energy expenditure derived by the two methods at rest before exercise and during the three different intensities of ambulatory exercise. There was a significant difference between energy expenditure derived via indirect calorimetry and with the accelerometer during rest after exercise, probably due to the failure of the accelerometer to accurately estimate the energy expenditure associated with the progressive decline in post-exercise oxygen consumption. Thus, this commercially available accelerometer appears to provide statistically acceptable estimates of energy expenditure at rest and during zero-grade treadmill ambulation up to about 70% VO2peak. This may indicate its acceptable utility for large-scale population studies of physical activity involving this mode of movement. The failure of the accelerometer to accurately estimate energy expenditure during recovery from exercise may contribute to an underestimation of energy expenditure in some physically active individuals.

Exercise training and the glucose transport system in obese SHHF/Mcc-fa(cp) rats.

The effects of a similar exercise training stimulus on maximal insulin-stimulated (MIS) plasma membrane glucose transporter number and glucose transport were determined in lean and obese SHHF/Mcc-facp rats. Six-week-old lean and obese male rats were randomly divided into four groups: lean sedentary (LSed), obese sedentary (OSed), lean exercise (LEx), and obese exercise (OEx). An 8- to 12-wk treadmill running program equalized daily muscular work for LEx and OEx. Plasma membranes were isolated from control and MIS muscles of mixed fiber types. MIS significantly increased glucose transport (3.4- and 2.8-fold) in LSed and OSed, respectively. MIS significantly increased glucose transporter number (2.5-fold) in LSed, but there was no increase in glucose transporter number in OSed. Peak oxygen uptake and citrate synthase activity were increased a similar amount for LEx and OEx groups, demonstrating a similar training stimulus. MIS significantly and similarly increased glucose transport in LEx and OEx (4.4- and 5.1-fold, respectively). The effects of MIS on plasma membrane glucose transporter number in the exercise-trained rats were similar to the responses observed in the sedentary lean and obese groups. MIS significantly increased glucose transporter number (2.6-fold) in LEx, whereas there was no increase in glucose transporter number in OEx. The reduction in MIS glucose transport in OSed appears to be related to a defect in the processes associated with the translocation of glucose transporters to the plasma membrane. Exercise training of the obese rats apparently did not alter this defect. Similar increases in peak oxygen uptake, citrate synthase, and MIS glucose transport in LEx and OEx groups suggest that insulin resistance does not limit the ability of the glucose transport system to adapt to exercise training in the obese male SHHF/Mcc-facp rats.

Fat loading: the next magic bullet?

The depletion or reduction of bodily carbohydrate reserves is associated with fatigue during endurance exercise. Various carbohydrate supplementation and exercise regimens have been used experimentally to increase carbohydrate reserves before exercise or to maintain the availability of carbohydrate for oxidation during exercise. On the other hand, the improved endurance capability observed after aerobic training has been attributed to an increased oxidation of fat relative to carbohydrate; this carbohydrate sparing presumably delays the point at which reduced carbohydrate reserves cause fatigue. This effect has led to the suggestion that a greater availability of fat during exercise can improve performance via the carbohydrate-sparing effect of "fat loading." Although this is a plausible hypothesis, it is not supported by a sufficient number of valid, credible, and replicated studies. Thus, it appears prudent to advise endurance athletes to consume a diet that is largely carbohydrate to optimize training and competitive performance and, more importantly, to promote optimal health.