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Sean Carroll

Publications and source records attributed to Sean Carroll.

12 recordsLinked to original sources
PubMed2006

Prognostic value of the VE/VCO2 slope calculated from different time intervals in patients with suspected heart failure.

BACKGROUND: Maximal exercises testing, whether involving cycling- or walking-based protocols, are often not well tolerated in patients with chronic heart failure (CHF). The peak oxygen consumption and the slope of the relation between ventilation (V(E)) and carbon dioxide production (V(CO(2))) are independent predictors of outcome and help risk stratification. The prognostic usefulness of submaximal exercise testing is not clear. The aim of the present study was to assess the prognostic value of the V(E)/V(CO(2)) slope when derived from data acquired from submaximal exercise. METHODS: 394 patients referred with breathlessness and suspected heart failure (74% male) (mean+/-S.D.) age 60+/-12 years; BMI 27+/-5 performed a CPET to determine peak V(O(2)) and the V(E)/V(CO(2)) slope. The V(E)/V(CO(2)) slope was calculated using least squares regression from data acquired from the first 25% of exercise (mean V(E)/V(CO(2)) slope+/-SD; 30.6+/-5.7), 50% (29.6+/-6.9), below the ventilatory compensation point (sub-VCP) (29.9+/-6.8), and all data points (full slope) (32.1+/-7.8). For each measure, patients were divided into quartiles and Kaplan-Meier curves were constructed to determine probability of death after 24 months. The prognostic value of the different classifications was assessed using the chi(2) statistic from the Mantel-Cox log-rank test. RESULTS: During a mean follow-up period of 41+/-19 months, 48 patients died. For the V(E)/V(CO(2)) slope, the log-rank statistic was greatest for the full slope (chi(2)=53.7; P=0.0001), followed by the sub-VCP (chi(2)=45.5; P=0.0001), 50% (chi(2)=41.9; P=0.0001), and 25% (chi(2)= 26.0; P=0.01). The pair-wise log-rank statistic between the fourth and third quartiles was also greatest using the full slope (chi(2)=25.4; P=0.001) followed in order by the sub-VCP (chi(2)=20.1; P=0.001), 50% (chi(2)=19.7; P=0.001), and 25% (chi(2)=14.2; P=0.05). Using the stratified slope measurements entered into a Cox regression analysis using a forward LR stepwise elimination procedure; only the full slope remained significant (P=0.0001). CONCLUSIONS: The V(E)/V(CO(2)) slope should be calculated from all data points to optimise prognostic sensitivity. Data acquired from the first 50% of exercise and below the VCP provide adequate prognostic surrogates in patients who may not be able to perform maximal exercise testing (i.e. in patients with a respiratory exchange ratio<1.10).

Aged↗
PubMed2006

Topical ciprofloxacin/dexamethasone superior to oral amoxicillin/clavulanic acid in acute otitis media with otorrhea through tympanostomy tubes.

OBJECTIVE: This study was a comparison of topical ciprofloxacin/dexamethasone otic suspension to oral amoxicillin/clavulanic acid suspension in children with acute otitis media with otorrhea through tympanostomy tubes. METHODS: This was a randomized, observer-masked, parallel-group, multicenter trial of topical ciprofloxacin/dexamethasone otic suspension versus amoxicillin/clavulanic acid suspension in 80 children aged 6 months to 12 years with acute otitis media with otorrhea through tympanostomy tubes of < or = 3 weeks' duration and visible otorrhea. Patients were randomly assigned to receive either 4 drops of topical ciprofloxacin 0.3%/dexamethasone 0.1% (Ciprodex Sterile Otic Suspension) into the affected ear(s) twice daily for 7 days or 600 mg of amoxicillin/42.9 mg of clavulanic acid oral suspension (Augmentin ES-600 Oral Suspension) every 12 hours for 10 days. Clinical signs and symptoms of acute otitis media with otorrhea through tympanostomy tubes were evaluated on days 1 (baseline), 3, 11 (end-of-therapy), and 18 (test-of-cure), and twice-daily assessments of otorrhea were recorded in patient diaries. RESULTS: The median time to cessation of otorrhea was significantly shorter with ciprofloxacin/dexamethasone otic suspension than with amoxicillin/clavulanic acid suspension (4.0 vs 7.0 days; n = 79). This resulted in significantly more clinical cures at the test-of-cure visit (85% vs 59%, respectively). Frequent adverse events (> 3%) related to ciprofloxacin/dexamethasone otic suspension included ear pain (5.1%) and related to amoxicillin/clavulanic acid suspension included diarrhea (19.5%), dermatitis (7.3%), and gastroenteritis (4.9%). CONCLUSIONS: Topical otic treatment with ciprofloxacin/dexamethasone otic suspension is superior to treatment with oral amoxicillin/clavulanic acid suspension and results in more clinical cures and earlier cessation of otorrhea with fewer adverse effects in children with acute otitis media with otorrhea through tympanostomy tubes.

Acute Disease↗
PubMed2006

Verification phase as a useful tool in the determination of the maximal oxygen uptake of distance runners.

This study investigated the utility of a verification phase for increasing confidence that a "true" maximal oxygen uptake had been elicited in 16 male distance runners (mean age (+/-SD), 38.7 (+/- 7.5 y)) during an incremental treadmill running test continued to volitional exhaustion. After the incremental test subjects performed a 10 min recovery walk and a verification phase performed to volitional exhaustion at a running speed 0.5 km.h(-1) higher than that attained during the last completed stage of the incremental phase. Verification criteria were a verification phase peak oxygen uptake or= 3%) lower than the peak values attained in the incremental phase. Further research is required to improve the verification procedure before its utility can be confirmed.

Adult↗
PubMed2006

Progressive high-intensity resistance training and bone mineral density changes among premenopausal women: evidence of discordant site-specific skeletal effects.

Regular weight-bearing physical activity has been widely recommended for adult women and may be beneficial in preserving bone mineral density (BMD). However, there is conflicting evidence regarding the effects of resistance training on BMD in premenopausal women. Novel systematic review and meta-analysis evidence is presented on the effects of progressive high-intensity resistance training on BMD in premenopausal women. Structured computer searches of MEDLINE, EMBASE, PubMed, Web of Science, SportDiscus and Evidence Based Medicine Reviews Multifile were undertaken along with hand-searching of key journals and reference lists to locate relevant studies published up to September 2004. Criteria for included studies were published controlled studies and randomised controlled trials (RCTs) evaluating the effects of progressive, high-intensity resistance training studies on BMD in premenopausal women. Two authors reached consensus on all included and excluded studies. Study outcomes for analysis were radiographic BMD assessment from first follow-up at lumbar spine and femoral neck. Primary outcomes for analysis were absolute changes in BMD g/cm(2) at lumbar spine and femoral neck. Relative changes (percentage change) in BMD at lumbar spine were also assessed. Data were extracted from studies including study design, participant characteristics and treatment mode, intensity and duration, using electronic data extraction forms. Where necessary, relevant information was obtained by contacting study authors. Methodological quality of studies was assessed using a well recognised three-question instrument designed to assess bias. Informal assessment for small sample study effects and potential bias was undertaken through visual inspection of funnel plots. The weighted mean difference method (inverse of the variances) was used for combining study group estimates. Quantification of the effect of heterogeneity among study outcomes was assessed using the I(2) statistic. Random effects and fixed-effect models were applied according to observed study heterogeneity. Comparisons resulting in I(2) > 50.0% were considered heterogeneous. Where heterogeneity was observed, a random effects model was applied. Pooled estimates of effect were calculated using the Cochrane Collaboration's Review Manager (RevMan) 4.2.1 software.High-intensity progressive resistance training was shown to be efficacious in increasing absolute BMD at the lumbar spine (p < 0.00001) but not the femoral neck (p = 0.78) in premenopausal women. The weighted mean difference (WMD) using a fixed-effect model for six controlled trials investigating the lumbar spine BMD change was 0.014 g/cm(2) (95% CI 0.009, 0.019; p < 0.00001). The relative BMD change for this site was 0.98% (WMD [random effects], 95% CI 0.49, 3.91%; p = 0.04). In contrast, studies evaluating femoral neck BMD changes showed no significant BMD change (WMD [fixed effect], 0.001 g/cm(2) 95% CI -0.006, 0.008; p = 0.78). Funnel plot inspection of lumbar spine effects indicated that smaller studies demonstrated larger treatment effects. An asymmetry towards studies with positive BMD outcomes was also noted. The methodological quality score of all included studies was low and no study presented a valid intention-to-treat accounting for participant drop-out (attrition). As such, the modest overall treatment effects for resistance training on BMD among premenopausal women observed in this review may be biased and should be interpreted with caution. It is concluded that further RCTs of resistance training of sufficiently long duration and providing optimum type, intensity and volume of loading, with intention-to-treat analysis are now required.

Bone Density↗
PubMed2005

Percentage fat in overweight and obese children: comparison of DXA and air displacement plethysmography.

OBJECTIVE: To compare percentage body fat (percentage fat) estimates from DXA and air displacement plethysmography (ADP) in overweight and obese children. RESEARCH METHODS AND PROCEDURES: Sixty-nine children (49 boys and 20 girls) 14.0+/-1.65 years of age, with a BMI of 31.3+/-5.6 kg/m2 and a percentage fat (DXA) of 42.5+/-8.4%, participated in the study. ADP body fat content was estimated from body density (Db) using equations devised by Siri (ADP(Siri)) and Lohman (ADP(Loh)). RESULTS: ADP estimates of percentage fat were highly correlated with those of DXA in both male and female subjects (r=0.90 to 0.93, all p<0.001; standard error of estimate=2.50% to 3.39%). Compared with DXA estimates, ADP(Siri) and ADP(Loh) produced significantly (p<0.01) lower estimates of mean body fat content in boys (-2.85% and -4.64%, respectively) and girls (-2.95% and -5.15%, respectively). Agreement between ADP and DXA methods was further examined using the total error and methods of Bland and Altman. Total error ranged from 4.46% to 6.38% in both male and female subjects. The 95% limits of agreement were relatively similar for all percentage fat estimates, ranging from +/-6.73% to +/-7.94%. DISCUSSION: In this study, conversion of Db using the Siri equation led to mean percentage fat estimates that agreed better with those determined by DXA compared with the Lohman equations. However, relatively high limits of agreement using either equation resulted in percentage fat estimates that were not interchangeable with percentage fat determined by DXA.

Absorptiometry, Photon↗
PubMed2004

Insignificance.

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Journal Article↗
PubMed2004

What is the relationship between exercise and metabolic abnormalities? A review of the metabolic syndrome.

Prevention of the metabolic syndrome and treatment of its main characteristics are now considered of utmost importance in order to combat the epidemic of type 2 diabetes mellitus and to reduce the increased risk of cardiovascular disease and all-cause mortality. Insulin resistance/hyperinsulinaemia are consistently linked with a clustering of multiple clinical and subclinical metabolic risk factors. It is now widely recognised that obesity (especially abdominal fat accumulation), hyperglycaemia, dyslipidaemia and hypertension are common metabolic traits that, concurrently, constitute the distinctive insulin resistance or metabolic syndrome. Cross-sectional and prospective data provide an emerging picture of associations of both physical activity habits and cardiorespiratory fitness with the metabolic syndrome. The metabolic syndrome, is a disorder that requires aggressive multi-factorial intervention. Recent treatment guidelines have emphasised the clinical utility of diagnosis and an important treatment role for 'therapeutic lifestyle change', incorporating moderate physical activity. Several previous narrative reviews have considered exercise training as an effective treatment for insulin resistance and other components of the syndrome. However, the evidence cited has been less consistent for exercise training effects on several metabolic syndrome variables, unless combined with appropriate dietary modifications to achieve weight loss. Recently published randomised controlled trial data concerning the effects of exercise training on separate metabolic syndrome traits are evaluated within this review. Novel systematic review and meta-analysis evidence is presented indicating that supervised, long-term, moderate to moderately vigorous intensity exercise training, in the absence of therapeutic weight loss, improves the dyslipidaemic profile by raising high density lipoprotein-cholesterol and lowering triglycerides in overweight and obese adults with characteristics of the metabolic syndrome. Lifestyle interventions, including exercise and dietary-induced weight loss may improve insulin resistance and glucose tolerance in obesity states and are highly effective in preventing or delaying the onset of type 2 diabetes in individuals with impaired glucose regulation. Randomised controlled trial evidence also indicates that exercise training decreases blood pressure in overweight/obese individuals with high normal blood pressure and hypertension. These evidence-based findings continue to support recommendations that supervised or partially supervised exercise training is an important initial adjunctive step in the treatment of individuals with the metabolic syndrome. Exercise training should be considered an essential part of 'therapeutic lifestyle change' and may concurrently improve insulin resistance and the entire cluster of metabolic risk factors.

Cross-Sectional Studies↗