•Association of education and change in cognitive performance is negligible.•Articles included in meta-analysis displayed high unexplained heterogeneity.•Theories of cognitive aging need to be ...updated with regards to this association.
Central theories of cognitive aging propose that education is an important protective factor for decline in cognitive performance in older age. We conducted a systematic review and meta-analysis of reported estimates of an association between educational attainment and change in performance in six cognitive domains (episodic memory, processing speed, verbal fluency, crystallized intelligence, fluid intelligence, and global ability) in the general population of older individuals. The systematic search (11th of October 2019) identified 92 eligible articles. The episodic memory domain had the highest number of estimates (37 estimates from 18 articles, n = 109,281) included in the meta-analysis. The fewest estimates (6 estimates from 6 articles, n = 5263) were included for fluid intelligence. Pooled mean estimates from an inverse-variance weighted random effects analysis were not statistically significant and indicated that any association between education and change in cognitive performance is likely of a negligible magnitude. The estimates for education’s role (one additional year) for change in cognitive performance ranged from -0.019 (95 % confidence interval, CI = -0.047, 0.010) to 0.004SD (CI = -0.003, 0.012) per decade. Even if the larger positive point estimates (i.e., protective effects) are selectively considered, the influence of education on change is still at least 12 times less important for the cognitive functioning of an older individual than the association between education and level of cognitive performance. Sensitivity analyses did not substantially alter these results. However, heterogeneity was substantial, and remained largely unexplained by mean age, mean educational attainment, Gini coefficient, GDP per capita, maximum follow-up period, and publication year. Overall, education is an important factor in aging due to its robust association with level of performance, but the current base of empirical evidence is not revealing a consistent and substantial association between educational attainment and changes in cognitive performance in the general population. Theories of cognitive aging must be updated to incorporate this pattern of findings.
Increased Secretion and Expression of Myostatin in Skeletal Muscle From Extremely Obese Women
Dustin S. Hittel 1 ,
Jason R. Berggren 2 ,
Jane Shearer 1 ,
Kristen Boyle 2 and
Joseph A. Houmard 2
1 ...Human Performance Laboratory, Faculty of Kinesiology, Roger Jackson Center for Health and Wellness, University of Calgary,
Calgary, Alberta, Canada
2 Human Performance Laboratory and Department of Exercise and Sport Science, East Carolina University, Greenville, North Carolina
Corresponding author: Dustin S. Hittel, dhittel{at}kin.ucalgary.ca
Abstract
OBJECTIVE— Obesity is associated with endocrine abnormalities that predict the progression of insulin resistance to type 2 diabetes.
Because skeletal muscle has been shown to secrete proteins that could be used as biomarkers, we characterized the secreted
protein profile of muscle cells derived from extremely obese (BMI 48.8 ± 14.8 kg/m 2 ; homeostasis model assessment HOMA 3.6 ± 1.0) relative to lean healthy subjects (BMI 25.7 ± 3.2 kg/m 2 ; HOMA 0.8 ± 0.2).
RESEARCH DESIGN AND METHODS— We hypothesized that skeletal muscle would secrete proteins that predict the severity of obesity. To test this hypothesis,
we used a “bottom-up” experimental design using stable isotope labeling by amino acids in culture (SILAC) and liquid chromatography/mass
spectometry/mass spectometry (LC-MS/MS) to both identify and quantify proteins secreted from cultured myotubes derived from
extremely obese compared with healthy nonobese women.
RESULTS— Using SILAC, we discovered a 2.9-fold increase in the secretion of myostatin from extremely obese human myotubes. The increased
secretion and biological activity of myostatin were validated by immunoblot (3.16 ± 0.18, P < 0.01) and a myoblast proliferation assay using conditioned growth medium. Myostatin was subsequently shown to increase
in skeletal muscle (23%, P < 0.05) and plasma (35%, P < 0.05) and to correlate ( r 2 = 0.6, P < 0.05) with the severity of insulin resistance.
CONCLUSIONS— Myostatin is a potent antianabolic regulator of muscle mass that may also play a role in energy metabolism. These findings
show that increased expression of myostatin in skeletal muscle with obesity and insulin resistance results in elevated circulating
myostatin. This may contribute to systemic metabolic deterioration of skeletal muscle with the progression of insulin resistance
to type 2 diabetes.
Footnotes
Published ahead of print at http://diabetes.diabetesjournals.org on 3 October 2008.
Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work
is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore
be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
Accepted September 19, 2008.
Received July 14, 2008.
DIABETES
Abstract
This paper reports on laboratory-based treatability and field quality assurance (QA) testing completed on interbedded sands and silts at an industrial site heavily impacted by a ...chlorobenzene (CB)-rich nonaqueous phase liquid (NAPL) to depths of approximately 30 ft (9.1 m) below the ground surface (bgs). Total CB concentrations were measured up to 4,200 and 11,000 mg/kg in untreated sandy and silty soil samples, respectively. EPA 1316M testing indicated that the effective solubility of CB was on the order of 90–210 mg/L in two of the most impacted sand samples, the highest of which (from hotspot location 4370) was selected as the principal threat waste condition. A full depth 25 ft (7.6 m) soil core from this location was homogenized to form a soil surrogate containing approximately 1,500 mg/kg CB. Three stabilization/solidification (S/S) mix designs using Type I/II portland cement (PC) doses ranging from 5 to 10 wt% were then prepared using the soil surrogate. The unconfined compressive strength (UCS) and hydraulic conductivity (K) values after 28 days of curing were, respectively, on the order of 190–265 lb/in.2 (1.31–1.83 MPa) and 1.0 × 10−9 cm/s, easily meeting the performance criteria. All mix designs showed essentially the same EPA 1315M leaching response, with percent leaching reductions (%LRs) greater than 99% for CB and benzene (B) compared with the untreated sand. This was well above the minimum of 90% LR established for successful mix designs. During remedial construction, bucket and auger S/S-mixing techniques using 7.5 wt% PC were used to treat approximately 9,335 CY of impacted soils to depths up to 30 ft (9.1 m) bgs (12 bucket-mixed cells and 527 auger columns) in approximately 6 months. The UCS and K criteria were both satisfied. The relative vertical positioning of the EPA 1315M cumulative mass release curves for CB from the field QA samples appeared to be more strongly influenced by the total CB content than by K, because all S/S-treated samples were characterized by K < 1 × 10−6 cm/s (i.e., were diffusion-controlled). EPA 1315M testing of the field-mixed sample from hotspot location 4370 again indicated %LRs greater than 99% for both CB and B. Samples from a second location in the western portion of the ISS treatment area demonstrated similar results.
Results are presented from a chemostat study where the reductive dehalogenation of PCE was evaluated in the absence and presence of sulfate. Two chemostats inoculated with the Point Mugu culture, ...which contains strains of Dehalococcoides mccartyi, were operated at a 50 day HRT and fed PCE (1.12 mM) and lactate (4.3 mM). The control chemostat (PM-5L, no sulfate), achieved pseudo-steady-state transformation of PCE to ethene (98%) and VC (2%) at 2.4 nM of H2. Batch kinetic tests with chemostat harvested cells showed the maximum rate (k maxX) value for each dehalogenation step remained fairly constant, while hupL clone library analyses showed maintenance of a diverse D. mccartyi community. Sulfate (1 mM) was introduced to the second chemostat, PM-2L. Effective sulfate reduction was achieved 110 days later, resulting in 600 μM of total sulfide. PCE dechlorination efficiency decreased following complete sulfate reduction, yielding ethene (25%), VC (67%), and cis-DCE (8%). VC dechlorination was most affected, with k maxX values decreasing by a factor of 50. The decrease was associated with the enrichment of the Cornell group of D. mccartyi and decline of the Pinellas group. Long-term exposure to sulfides and/or competition for H2 may have been responsible for the community shift.
1 Human Performance Laboratory, 2 Department of Exercise and Sport Science, 3 Diabetes and Obesity Center, and 4 Department of Surgery, East Carolina University, Greenville, North Carolina
Submitted ...7 June 2007
; accepted in final form 3 February 2008
Obesity is associated with a decrement in the ability of skeletal muscle to oxidize lipid. The purpose of this investigation was to determine whether clinical interventions (weight loss, exercise training) could reverse the impairment in fatty acid oxidation (FAO) evident in extremely obese individuals. FAO was assessed by incubating skeletal muscle homogenates with 1- 14 Cpalmitate and measuring 14 CO 2 production. Weight loss was studied using both cross-sectional and longitudinal designs. Muscle FAO in extremely obese women who had lost weight (decrease in body mass of 50 kg) was compared with extremely obese and lean individuals (BMI of 22.8 ± 1.2, 50.7 ± 3.9, and 36.5 ± 3.5 kg/m 2 for lean, obese, and obese after weight loss, respectively). There was no difference in muscle FAO between the extremely obese and weight loss groups, and FAO was depressed (–45%; P 0.05) compared with the lean subjects. Muscle FAO also did not change in extremely obese women ( n = 8) before and 1 yr after a 55-kg weight loss. In contrast, 10 consecutive days of exercise training increased ( P 0.05) FAO in the skeletal muscle of lean (+1.7-fold), obese (+1.8-fold), and previously extremely obese subjects after weight loss (+2.6-fold). mRNA content for PDK4, CPT I, and PGC-1 corresponded with FAO in that there were no changes with weight loss and an increase with physical activity. These data indicate that a defect in the ability to oxidize lipid in skeletal muscle is evident with obesity, which is corrected with exercise training but persists after weight loss.
extreme obesity; fat oxidation; gastric bypass surgery; mitochondria; physical activity
Address for reprint requests and other correspondence: J. A. Houmard, 363 Ward Sports Medicine Bldg., East Carolina University, Greenville, NC 27858 (e-mail: houmardj{at}ecu.edu )
Abstract
Fifteen soil–cement mix designs, cured for up to 270 days, were tested on sand and peaty sands from a Waterfront Toronto Brownfields site having a total petroleum hydrocarbon (TPHC) ...concentration of approximately 20,000 mg/kg. The peaty sand was created using fibrous peat and sands from the site blended at a 25:75 v/v ratio to reflect the lithology targeted for stabilization/solidification (S/S). Portland slag–cement blends (6–14 wt%) added to wet soil with 0.5 wt% bentonite applied to the sandy soil provided 28-day unconfined compressive strengths (UCSs) of the order of 400–2,500 kPa, which increased to approximately 700–4,300 kPa by 56 days. The performance of the peaty sands was lower: 8–25 wt% cement blends with 0.5 wt% bentonite had UCSs of approximately 140–1,725 kPa at 28 days and 175–3,400 kPa by 56 days. Brazilian tensile strengths of the S/S-treated soils were 10%–16% of UCSs. The minimum cement doses to pass the freeze/thaw test (12 cycles; ASTM D560) after 28 days were 10 and 25 wt% for the sandy and peaty sand soils, respectively. For similar reagent doses, the sandy soil mixes were typically 3–130 times less permeable than the peaty sand mixes after 28 days curing, with all mix designs except one having a hydraulic conductivity less than 10−6 cm/s. Total (n) and effective (neff) porosity testing conducted at 210 days showed that the sandy soil mixes had values of n and neff that were, respectively, 20% and 85%–90% less than the peaty sand mixes. The maximum values of neff of the S/S-treated sands and peaty sands were 9% and 14%, respectively. Computed tomography (CT) of the S/S-treated soils at 210 days confirmed the porosity trends and provided insight into the freeze/thaw failures of the peaty sands. TPHC leaching of the untreated soils and select 28-day cured mix designs as a function of the liquid/solid (L/S) ratio were similar, consistent with other studies where particle crushing of the S/S-treated materials occurred.
AbstractThis paper is the first in a series presenting engineering data sets that successfully supported the permit approval process in a US midwestern state bordering the Great Lakes to use ...air-cooled blast furnace (ACBF) slag for phosphate removal in passive stormwater runoff systems. The ACBF slag aggregates under consideration function as reactive base/subbase layers beneath porous pavement installations. Mineralogically, the ACBF slag was dominated by akermanite (Ca2MgSi2O7) and gehlenite (Ca2Al2SiO7), with a considerable amorphous phase as determined by quantitative X-ray diffraction (QXRD). ACBF slag samples taken from three different northern Indiana steel mills were tested for the United States Environmental Protection Agency (USEPA) target analyte list (TAL) metals after digestion for total content and after deionized water (DIW) leaching. Comparisons between the three strongly alkaline ACBF slags showed remarkable similarity, with many analytes below quantifiable limits due to their low levels. Synthetic precipitation leaching procedure (SPLP), toxicity characteristic leaching procedure (TCLP), and pH-dependent leaching (USEPA Method 1313) tests were also conducted. Comparisons of total content and SPLP concentrations with typical soils and soil-like media showed that the ACBF slag was often associated with a higher environmental quality. Above pH=8, the USEPA Method 1313 leaching of the Resource Conservation and Recovery Act metals was either not detected or was compliant with US federal drinking water criteria, illustrating that the naturally alkaline ACBF slag media are safe to use for passive water treatment. Moreover, acute ecotoxicity testing on ACBF slag leachates using C. dubia and P. promelas showed greater than 90% survival rate.
Objective
Determination of lactate in fetal scalp blood (FBS) during labour has been recognised since the 1970s. The internationally accepted cutoff of >4.8 mmol/l indicating fetal acidosis is ...exclusive for the point‐of‐care device (POC) LactatePro™, which is no longer in production. The aim of this study was to establish a new cutoff for scalp lactate based on neonatal outcomes with the use of the StatstripLactate®/StatstripXpress® Lactate system, the only POC designed for hospital use.
Design
Observational study.
Setting
January 2016 to March 2020 labouring women with indication for FBS were prospectively included from seven Swedish and one Australian delivery unit.
Population
Inclusion criteria: singleton pregnancy, vertex presentation, ≥35+0 weeks of gestation.
Method
Based on the optimal correlation between FBS lactate and cord pH/lactate, only cases with ≤25 minutes from FBS to delivery were included in the final calculations.
Main outcome measures
Metabolic acidosis in cord blood defined as pH <7.05 plus BDecf >10 mmol/l and/or lactate >10 mmol/l.
Results
A total of 3334 women were enrolled of whom 799 were delivered within 25 minutes. The areas under the receiver operating characteristics curves (AUC) and corresponding optimal cutoff values were as follows; metabolic acidosis AUC 0.87 (95% CI 0.77–0.97), cutoff 5.7 mmol/l; pH <7.0 AUC 0.83 (95% CI 0.68–0.97), cutoff 4.6 mmol/l; pH <7.05 plus BDecf ≥12 mmol/l AUC 0.97 (95% CI 0.92–1), cutoff 5.8 mmol/l; Apgar score <7 at 5 minutes AUC 0.74 (95% CI 0.63–0.86), cutoff 5.2 mmol/l; and pH <7.10 plus composite neonatal outcome AUC 0.76 (95% CI 0.67–0.85), cutoff 4.8 mmol/l.
Conclusion
A scalp lactate level <5.2 mmol/l using the StatstripLactate®/StatstripXpress® system will safely rule out fetal metabolic acidosis.
Tweetable
Scalp blood lactate <5.2 mmol/l using the StatstripLactate®/StatstripXpress system has an excellent ability to rule out fetal acidosis.
Tweetable
Scalp blood lactate <5.2 mmol/l using the StatstripLactate®/StatstripXpress® system has an excellent ability to rule out fetal acidosis.
This article includes Author Insights, a video available at https://vimeo.com/bjog/authorinsights16924
It has previously been demonstrated that short-term foreign language learning can lead to structural brain changes in younger adults. Experience-dependent brain plasticity is known to be possible ...also in older age, but the specific effect of foreign language learning on brain structure in language-and memory-relevant regions in the old brain remains unknown. In the present study, 160 older Swedish adults (65–75 years) were randomized to complete either an entry-level Italian course or a relaxation course, both with a total duration of 11 weeks. Structural MRI scans were conducted before and after the intervention in a subset of participants to test for differential change in gray matter in the two groups in the inferior frontal gyrus, the superior temporal gyrus, and the hippocampus, and in white matter microstructure in the superior longitudinal fasciculus (SLF), inferior longitudinal fasciculus (ILF), fronto-occipital fasciculus, and the hippocampal (HC) section of the cingulum. The study found no evidence for differential structural change following language training, independent of achieved vocabulary proficiency. However, hippocampal volume and associative memory ability before the intervention were found to be robust predictors of vocabulary proficiency at the end of the language course. The results suggest that having greater hippocampal volume and better associative memory ability benefits vocabulary learning in old age but that the very initial stage of foreign language learning does not trigger detectable changes in brain morphometry in old age.
We developed a broad-ranging method for identifying key hydrogen-producing and consuming microorganisms through analysis of hydrogenase gene content and expression in complex anaerobic microbial ...communities. The method is based on a tiling hydrogenase gene oligonucleotide DNA microarray (Hydrogenase Chip), which implements a high number of probes per gene by tiling probe sequences across genes of interest at 1.67 × -2 × coverage. This design favors the avoidance of false positive gene identification in samples of DNA or RNA extracted from complex microbial communities. We applied this technique to interrogate interspecies hydrogen transfer in complex communities in (i) lab-scale reductive dehalogenating microcosms enabling us to delineate key H(2)-consuming microorganisms, and (ii) hydrogen-generating microbial mats where we found evidence for significant H(2) production by cyanobacteria. Independent quantitative PCR analysis on selected hydrogenase genes showed that this Hydrogenase Chip technique is semiquantitative. We also determined that as microbial community complexity increases, specificity must be traded for sensitivity in analyzing data from tiling DNA microarrays.
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