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Concept: Crossover study


 To assess whether, as has been hypothesised since medieval times, acute fear can curdle blood.

Concepts: Blood, Crossover study, Coagulation


BACKGROUND: Bacteraemia is an important cause of morbidity and mortality in critically ill children. Our objective was to assess whether daily bathing in chlorhexidine gluconate (CHG) compared with standard bathing practices would reduce bacteraemia in critically ill children. METHODS: In an unmasked, cluster-randomised, two-period crossover trial, ten paediatric intensive-care units at five hospitals in the USA were randomly assigned a daily bathing routine for admitted patients older than 2 months, either standard bathing practices or using a cloth impregnated with 2% CHG, for a 6-month period. Units switched to the alternative bathing method for a second 6-month period. 6482 admissions were screened for eligibility. The primary outcome was an episode of bacteraemia. We did intention-to-treat (ITT) and per-protocol (PP) analyses. This study is registered with (identifier NCT00549393). FINDINGS: 1521 admitted patients were excluded because their length of stay was less than 2 days, and 14 refused to participate. 4947 admissions were eligible for analysis. In the ITT population, a non-significant reduction in incidence of bacteraemia was noted with CHG bathing (3·52 per 1000 days, 95% CI 2·64-4·61) compared with standard practices (4·93 per 1000 days, 3·91-6·15; adjusted incidence rate ratio [aIRR] 0·71, 95% CI 0·42-1·20). In the PP population, incidence of bacteraemia was lower in patients receiving CHG bathing (3·28 per 1000 days, 2·27-4·58) compared with standard practices (4·93 per 1000 days, 3·91-6·15; aIRR 0·64, 0·42-0·98). No serious study-related adverse events were recorded, and the incidence of CHG-associated skin reactions was 1·2 per 1000 days (95% CI 0·60-2·02). INTERPRETATION: Critically ill children receiving daily CHG bathing had a lower incidence of bacteraemia compared with those receiving a standard bathing routine. Furthermore, the treatment was well tolerated. FUNDING: Sage Products, US National Institutes of Health.

Concepts: Epidemiology, Clinical trial, Mortality rate, Medical statistics, Crossover study, Incidence, Chlorhexidine


OBJECTIVE: To compare a towel under, a warm water pad under or a forced warm air blanket over dogs as techniques to reduce heat loss during a standardized anesthetic. STUDY DESIGN: Prospective, randomized, crossover study. ANIMALS: Eight, healthy, mixed breed dogs weighing 16.3-19.6 kg. METHODS: Dogs were anesthetized four times for 90 minutes. Dogs were placed on a steel table (treatment TA), with a cotton towel (treatment TO) or a circulating warm water pad (treatment WP) between the dog and the table, or with, a towel under the dog and covered with a forced warm air blanket (treatment WAB). Rectal temperature (RT) was recorded at 5 minute intervals. Changes in temperature (ΔRT) were calculated as the RT at a given point subtracted from the RT before anesthesia (baseline) and compared over time. RESULTS: After 90 minutes of anesthesia, the ΔRT was 3.42 °C ± 0.29 for TA, 2.78 °C ± 0.43 for TO, 1.98 °C ± 0.29 for WP, and 0.91 °C ± 0.27 for WAB. Significant differences in ΔRT occurred between TA and WAB at 20 minutes (0.94 °C ± 0.42, p = 0.0206), between TO and WAB at 30 minutes (1.16 °C ± 0.62, p = 0.0063), between WP and WAB at 50 minutes (0.96 °C ± 0.98, p = 0.0249), between TA and WP at 35 minutes (1.19 °C ± 0.54, p = 0.0091), between TO and WP at 70 minutes (1.12 °C ± 0.56, p = 0.0248), and between TA and TO at 75 minutes (0.96 °C ± 0.62, p = 0.0313). These differences in ΔRT between each treatment persisted from the times indicated until the end of the anesthesia. CONCLUSION AND CLINICAL RELEVANCE: During anesthesia, forced warm air blankets were superior to other methods tested for limiting heat loss. An efficient heat loss technique should be used for anesthesia longer than 20 minutes duration in medium sized dogs.

Concepts: Crossover study, Thermodynamics, Heat, Anesthesia, Selective breeding, Dog breed, Anesthetic, Mixed-breed dog


Eight weeks of a high protein diet (>3 g/kg/day) coupled with a periodized heavy resistance training program has been shown to positively affect body composition with no deleterious effects on health. Using a randomized, crossover design, resistance-trained male subjects underwent a 16-week intervention (i.e., two 8-week periods) in which they consumed either their normal (i.e., habitual) or a higher protein diet (>3 g/kg/day). Thus, the purpose of this study was to ascertain if significantly increasing protein intake would affect clinical markers of health (i.e., lipids, kidney function, etc.) as well as performance and body composition in young males with extensive resistance training experience.

Concepts: Protein, Clinical trial, Human, Nutrition, Function, Crossover study, Clinical research, High protein diet


The aim of this exploratory study was to assess the safety and clinical effects of autologous umbilical cord blood (AUCB) infusion in children with idiopathic autism spectrum disorder (ASD). Twenty-nine children 2 to 6 years of age with a confirmed diagnosis of ASD participated in this randomized, blinded, placebo-controlled, crossover trial. Participants were randomized to receive AUCB or placebo, evaluated at baseline, 12, and 24 weeks, received the opposite infusion, then re-evaluated at the same time points. Evaluations included assessments of safety, Expressive One Word Picture Vocabulary Test, 4th edition, Receptive One Word Picture Vocabulary Test, 4th edition, Clinical Global Impression, Stanford-Binet Fluid Reasoning and Knowledge, and the Vineland Adaptive Behavior and Socialization Subscales. Generalized linear models were used to assess the effects of the response variables at the 12- and 24-week time periods under each condition (AUCB, placebo). There were no serious adverse events. There were trends toward improvement, particularly in socialization, but there were no statistically significant differences for any endpoints. The results of this study suggest that autologous umbilical cord infusions are safe for children with ASD. Tightly controlled trials are necessary to further progress the study of AUCB for autism. Stem Cells Translational Medicine 2018.

Concepts: Pharmacology, Clinical trial, Crossover study, Clinical research, Umbilical cord, Cord blood, Wharton's jelly, Autism spectrum


Nicotinamide adenine dinucleotide (NAD+) has emerged as a critical co-substrate for enzymes involved in the beneficial effects of regular calorie restriction on healthspan. As such, the use of NAD+precursors to augment NAD+bioavailability has been proposed as a strategy for improving cardiovascular and other physiological functions with aging in humans. Here we provide the evidence in a 2 × 6-week randomized, double-blind, placebo-controlled, crossover clinical trial that chronic supplementation with the NAD+precursor vitamin, nicotinamide riboside (NR), is well tolerated and effectively stimulates NAD+metabolism in healthy middle-aged and older adults. Our results also provide initial insight into the effects of chronic NR supplementation on physiological function in humans, and suggest that, in particular, future clinical trials should further assess the potential benefits of NR for reducing blood pressure and arterial stiffness in this group.

Concepts: Clinical trial, Enzyme, Blood, Heart, The Canon of Medicine, Crossover study, Nicotinamide adenine dinucleotide, Avicenna


The current study examined the adaptive response to both endurance (END) and sprint interval training (SIT) in a group of twenty-one recreationally active adults. All participants completed three weeks (four days/ week) of both END (30 minutes at ~65% VO2peak work rate (WR) and SIT (eight, 20-second intervals at ~170% VO2peak WR separated by 10 seconds of active rest) following a randomized crossover study design with a three-month washout period between training interventions. While a main effect of training was observed for VO2peak, lactate threshold, and submaximal heart rate (HR), considerable variability was observed in the individual responses to both END and SIT. No significant positive relationships were observed between END and SIT for individual changes in any variable. Non-responses were determined using two times the typical error (TE) of measurement for VO2peak (0.107 L/min), lactate threshold (15.7 W), and submaximal HR (10.7bpm). Non-responders in VO2peak, lactate threshold, and submaximal HR were observed following both END and SIT, however, the individual patterns of response differed following END and SIT. Interestingly, all individuals responded in at least one variable when exposed to both END and SIT. These results suggest that the individual response to exercise training is highly variable following different training protocols and that the incidence of non-response to exercise training may be reduced by changing the training stimulus for non-responders to three weeks of END or SIT.

Concepts: Crossover study, Exercise, Adaptive immune system, Variable, Running, Interval training, Renaissance music, Adaptive response


Interventions for autism are limited. The synthetic hormone oxytocin may provide a potential treatment to improve core social and behavioral difficulties in autism, but its efficacy has yet to be evaluated in young children who potentially may benefit to a greater extent. We investigated the efficacy, tolerability and safety of oxytocin treatment in young children with autism using a double-blind, randomized, placebo-controlled, crossover, clinical trial. Thirty-one children with autism received 12 International Units (IU) of oxytocin and placebo nasal spray morning and night (24 IU per day) for 5 weeks, with a 4-week washout period between each treatment. Compared with placebo, oxytocin led to significant improvements on the primary outcome of caregiver-rated social responsiveness. Overall, nasal spray was well tolerated, and the most common reported adverse events were thirst, urination and constipation. This study is the first clinical trial to support the potential of oxytocin as an early intervention for young children with autism to help improve social interaction deficits.Molecular Psychiatry advance online publication, 27 October 2015; doi:10.1038/mp.2015.162.

Concepts: Pharmacology, Clinical trial, Crossover study, Effectiveness, Oxytocin, Clinical research, Placebo, Adverse event


BACKGROUND: The consumption of beetroot juice on a low nitrate diet may lower blood pressure (BP) and therefore reduce the risk of cardiovascular events. However, it is unknown if its inclusion as part of a normal diet has a similar effect on BP. The aim of the study was to conduct a randomized controlled trial with free-living adults to investigate if consuming beetroot juice in addition to a normal diet produces a measureable reduction in BP. METHOD: Fifteen women and fifteen men participated in a double-blind, randomized, placebo-controlled, crossover study. Volunteers were randomized to receive 500 g of beetroot and apple juice (BJ) or a placebo juice (PL). Volunteers had BP measured at baseline and at least hourly for 24-h following juice consumption using an ambulatory blood pressure monitor (ABPM). Volunteers remained at the clinic for 1-h before resuming normal non-strenuous daily activities. The identical procedure was repeated 2-wk later with the drink (BJ or PL) not consumed on the first visit. RESULTS: Overall, there was a trend (P=0.064) to lower systolic blood pressure (SBP) at 6-h after drinking BJ relative to PL. Analysis in men only (n=13) after adjustment for baseline differences demonstrated a significant (P<0.05) reduction in SBP of 4 -- 5 mmHg at 6-h after drinking BJ. CONCLUSIONS: Beetroot juice will lower BP in men when consumed as part of a normal diet in free-living healthy adults.Trial registration: ACTRN12612000445875.

Concepts: Clinical trial, Randomized controlled trial, Blood pressure, Crossover study, Artery, Clinical research, Ambulatory blood pressure, Sphygmomanometer


Bread is consumed daily by billions of people, yet evidence regarding its clinical effects is contradicting. Here, we performed a randomized crossover trial of two 1-week-long dietary interventions comprising consumption of either traditionally made sourdough-leavened whole-grain bread or industrially made white bread. We found no significant differential effects of bread type on multiple clinical parameters. The gut microbiota composition remained person specific throughout this trial and was generally resilient to the intervention. We demonstrate statistically significant interpersonal variability in the glycemic response to different bread types, suggesting that the lack of phenotypic difference between the bread types stems from a person-specific effect. We further show that the type of bread that induces the lower glycemic response in each person can be predicted based solely on microbiome data prior to the intervention. Together, we present marked personalization in both bread metabolism and the gut microbiome, suggesting that understanding dietary effects requires integration of person-specific factors.

Concepts: Clinical trial, Bacteria, Gut flora, Nutrition, Effect, Crossover study, Effectiveness, Bread