Projected decrease in trail access in the Arctic.

Transportation systems in northern Canada are highly sensitive to climate change. We project how access to semi-permanent trails on land, water, and sea ice might change this century in Inuit Nunangat (the Inuit homeland in northern Canada), using CMIP6 projections coupled with trail access models developed with community members. Overall trail access is projected to diminish, with large declines in access for sea ice trails which play a central role for Inuit livelihoods and culture; limits to adaptation in southern regions of Inuit Nunangat within the next 40 years; a lengthening of the period when no trails are accessible; and an unequal distribution of impacts according to the knowledge, skills, equipment, and risk tolerance of trail users. There are opportunities for adaptation through efforts to develop skillsets and confidence in travelling in more marginal environmental conditions, which can considerably extend the envelope of days when trails are accessible and months when this is possible. Such actions could reduce impacts across emissions scenarios but their potential effectiveness declines at higher levels of global warming, and in southern regions only delays when sea ice trails become unusable.

Differential Impact of Index Stroke on Dementia Risk in African-Americans Compared to Whites.

OBJECTIVE: To compare whites and African-Americans in terms of dementia risk following index stroke. METHODS: The data consisted of billing and International Classification of Diseases, Ninth Revision diagnosis codes from the South Carolina Revenue and Fiscal Affairs office on all hospital discharges within the state between 2000 and 2012. The sample consisted of 68,758 individuals with a diagnosis of ischemic stroke prior to 2010 (49,262 white [71.65%] and 19,496 African-Americans [28.35%]). We identified individuals in the dataset who were subsequently diagnosed with any of 5 categories of dementia and evaluated time to dementia diagnosis in Cox Proportional Hazards models. We plotted cumulative hazard curves to illustrate the effect of race on dementia risk after controlling for age, sex, and occurrence of intervening stroke. RESULTS: Age at index stroke was significantly different between the 2 groups, with African-Americans being younger on average (70.0 [SD 12.5] in whites versus 64.5 [SD 14.1] in African-Americans, P < .0001). Adjusted hazard ratios revealed that African-American race increased risk for all 5 categories of dementia following incident stroke, ranging from 1.37 for AD to 1.95 for vascular dementia. Age, female sex, and intervening stroke likewise increased risk for dementia. CONCLUSIONS: African-Americans are at higher risk for dementia than whites within 5 years of ischemic stroke, regardless of dementia subtype. Incident strokes may have a greater likelihood of precipitating dementia in African-Americans due to higher prevalence of nonstroke cerebrovascular disease or other metabolic or vascular factors that contribute to cognitive impairment.

The role of environmental factors in search and rescue incidents in Nunavut, Canada.

OBJECTIVES: Unintentional injury is a leading cause of morbidity and mortality in Nunavut, where the importance of land-based activities and reliance on semi-permanent trails create unique risk profiles. Climate change is believed to be exacerbating these risks, although no studies have quantitatively examined links between environmental conditions and injury and distress in the Canadian Arctic. We examine the correlation between environmental conditions and land-based search and rescue (SAR) incidents across Nunavut. STUDY DESIGN: Case study. METHODS: Case data were acquired from the Canadian National Search and Rescue Secretariat. Gasoline sales from across the territory are then used to model land-use and exposure. We compare weather and ice conditions during 202 SAR incidents to conditions during 755 non-SAR days (controls) between 2013 and 2014. RESULTS: We show daily ambient temperature, ice concentration, ice thickness, and variation in types of ice to be correlated with SAR rates across the territory during the study period. CONCLUSIONS: These conditions are projected to be affected by future climate change, which could increase demand for SAR and increase injury rates in the absence of targeted efforts aimed at prevention and treatment. This study provides health practitioners and public health communities with clearer understanding to prepare, respond to, and prevent injuries across the Arctic.

Latent information in fluency lists predicts functional decline in persons at risk for Alzheimer disease.

OBJECTIVE: We constructed random forest classifiers employing either the traditional method of scoring semantic fluency word lists or new methods. These classifiers were then compared in terms of their ability to diagnose Alzheimer disease (AD) or to prognosticate among individuals along the continuum from cognitively normal (CN) through mild cognitive impairment (MCI) to AD. METHOD: Semantic fluency lists from 44 cognitively normal elderly individuals, 80 MCI patients, and 41 AD patients were transcribed into electronic text files and scored by four methods: traditional raw scores, clustering and switching scores, "generalized" versions of clustering and switching, and a method based on independent components analysis (ICA). Random forest classifiers based on raw scores were compared to "augmented" classifiers that incorporated newer scoring methods. Outcome variables included AD diagnosis at baseline, MCI conversion, increase in Clinical Dementia Rating-Sum of Boxes (CDR-SOB) score, or decrease in Financial Capacity Instrument (FCI) score. Receiver operating characteristic (ROC) curves were constructed for each classifier and the area under the curve (AUC) was calculated. We compared AUC between raw and augmented classifiers using Delong's test and assessed validity and reliability of the augmented classifier. RESULTS: Augmented classifiers outperformed classifiers based on raw scores for the outcome measures AD diagnosis (AUC .97 vs. .95), MCI conversion (AUC .91 vs. .77), CDR-SOB increase (AUC .90 vs. .79), and FCI decrease (AUC .89 vs. .72). Measures of validity and stability over time support the use of the method. CONCLUSION: Latent information in semantic fluency word lists is useful for predicting cognitive and functional decline among elderly individuals at increased risk for developing AD. Modern machine learning methods may incorporate latent information to enhance the diagnostic value of semantic fluency raw scores. These methods could yield information valuable for patient care and clinical trial design with a relatively small investment of time and money.

Lexical factors and cerebral regions influencing verbal fluency performance in MCI.

OBJECTIVE: To evaluate assumptions regarding semantic (noun), verb, and letter fluency in mild cognitive impairment (MCI) and Alzheimer disease (AD) using novel techniques for measuring word similarity in fluency lists and a region of interest (ROI) analysis of gray matter correlates. METHOD: Fifty-eight individuals with normal cognition (NC, n=25), MCI (n=23), or AD (n=10) underwent neuropsychological tests, including 10 verbal fluency tasks (three letter tasks [F, A, S], six noun categories [animals, water creatures, fruits and vegetables, tools, vehicles, boats], and verbs). All pairs of words generated by each participant on each task were compared in terms of semantic (meaning), orthographic (spelling), and phonemic (pronunciation) similarity. We used mixed-effects logistic regression to determine which lexical factors were predictive of word adjacency within the lists. Associations between each fluency raw score and gray matter volumes in sixteen ROIs were identified by means of multiple linear regression. We evaluated causal models for both types of analyses to specify the contributions of diagnosis and various mediator variables to the outcomes of word adjacency and fluency raw score. RESULTS: Semantic similarity between words emerged as the strongest predictor of word adjacency for all fluency tasks, including the letter fluency tasks. Semantic similarity mediated the effect of cognitive impairment on word adjacency only for three fluency tasks employing a biological cue. Orthographic similarity was predictive of word adjacency for the A and S tasks, while phonemic similarity was predictive only for the S task and one semantic task (vehicles). The ROI analysis revealed different patterns of correlations among the various fluency tasks, with the most common associations in the right lower temporal and bilateral dorsal frontal regions. Following correction with gray matter volumes from the opposite hemisphere, significant associations persisted for animals, vehicles, and a composite nouns score in the left inferior frontal gyrus, but for letter A, letter S, and a composite FAS score in the right inferior frontal gyrus. These regressions also revealed a lateralized association of the left subcortical nuclei with all letter fluency scores and fruits and vegetables fluency, and an association of the right lower temporal ROI with letter A, FAS, and verb fluency. Gray matter volume in several bihemispheric ROIs (left dorsal frontal, right lower temporal, right occipital, and bilateral mesial temporal) mediated the relationship between cognitive impairment and fluency for fruits and vegetables. Gray matter volume in the right lower temporal ROI mediated the relationship between cognitive impairment and five fluency raw scores (animals, fruits and vegetables, tools, verbs, and the composite nouns score). CONCLUSION: Semantic memory exerts the strongest influence on word adjacency in letter fluency as well as semantic verbal fluency tasks. Orthography is a stronger influence than pronunciation. All types of fluency task raw scores (letter, noun, and verb) correlate with cerebral regions known to support verbal or nonverbal semantic memory. The findings emphasize the contribution of right hemisphere regions to fluency task performance, particularly for verb and letter fluency. The relationship between diagnosis and semantic fluency performance is mediated by semantic similarity of words and by gray matter volume in the right lower temporal region.

Hypersexuality and hemiballism due to subthalamic infarction.

OBJECTIVE: A 70-year-old right-handed man presented with a subthalamic infarction followed by persistent hypersexuality and hemiballism. A lacunar infarction 1 cm in diameter was observed on magnetic resonance imaging. We hypothesized that metabolic abnormalities would be detected in cortical areas related to his neurobehavioral symptoms. BACKGROUND: Statistical validation of the regional metabolic changes that may relate to neuropsychiatric symptoms has been elusive. Relating metabolic changes to neuropsychiatric symptoms is especially important in unique neurobehavioral cases. METHOD: Quantitative fluorodeoxyglucose positron emission tomography was obtained for a single-subject comparison with scans from 60 healthy subjects. RESULTS: Substantial glucose hypometabolism (p <0.001, uncorrected; [df = 56]) was identified in the subthalamic nucleus at the site of the lacunar infarction. Hypermetabolism (p <0.01) was identified within the basal forebrain and temporal lobes, anterior cingulate and medial prefrontal cortices (areas previously associated with hypersexuality), and striatum (p <0.001) ipsilateral to the stroke (areas known to relate to hemiballism). CONCLUSIONS: Single-subject statistical parametric mapping may improve our understanding of unique neurobehavioral cases.

Effect of pollination and exogenous ethylene on accumulation of ETR1 homologue transcripts during flower petal abscission in geranium (Pelargonium x hortorum L.H. Bailey).

We have isolated two cDNAs from geranium, PhETR1 and PhETR2. The deduced amino acid sequences of PhETR1 anti PhETR2 share 78% and 79% identity with ETR1 from Arabidopsis thaliana respectively. These genes are members of a multigene family and are expressed at moderate levels in leaves, pedicels, sepals, pistils and petals, and at very low levels in roots. PhETR1 and PhETR2 mRNAs are expressed in geranium florets long before they are receptive to pollination and transcript levels remain constant throughout floral development. Message levels of PhETR1 and PhETR2 in pistils and receptacles are unaffected by self-pollination or treatment with 1 micro/l ethylene that induces petal abscission. Our results indicate that the amount of PhETR1 and PHETR2 mRNA is not indicative of the level of sensitivity of geranium florets to ethylene.

Root formation in ethylene-insensitive plants.

Experiments with ethylene-insensitive tomato (Lycopersicon esculentum) and petunia (Petunia x hybrida) plants were conducted to determine if normal or adventitious root formation is affected by ethylene insensitivity. Ethylene-insensitive Never ripe (NR) tomato plants produced more below-ground root mass but fewer above-ground adventitious roots than wild-type Pearson plants. Applied auxin (indole-3-butyric acid) increased adventitious root formation on vegetative stem cuttings of wild-type plants but had little or no effect on rooting of NR plants. Reduced adventitious root formation was also observed in ethylene-insensitive transgenic petunia plants. Applied 1-aminocyclopropane-1-carboxylic acid increased adventitious root formation on vegetative stem cuttings from NR and wild-type plants, but NR cuttings produced fewer adventitious roots than wild-type cuttings. These data suggest that the promotive effect of auxin on adventitious rooting is influenced by ethylene responsiveness. Seedling root growth of tomato in response to mechanical impedance was also influenced by ethylene sensitivity. Ninety-six percent of wild-type seedlings germinated and grown on sand for 7 d grew normal roots into the medium, whereas 47% of NR seedlings displayed elongated tap-roots, shortened hypocotyls, and did not penetrate the medium. These data indicate that ethylene has a critical role in various responses of roots to environmental stimuli.

Resting metabolic rate, body composition and aerobic fitness comparisons between active and sedentary 54-71 year old males.

OBJECTIVE: To test the hypothesis that 55-70 y old male longterm exercisers (LE) have higher resting metabolic rates (RMR) than longterm nonexercisers (LNE). DESIGN: A power analysis demonstrated that this cross-sectional study required 12 subjects per group to detect a 10% RMR difference (kJ x kg FFM(-1) x d(-1)) between the LE and LNE (power = 0.8;alpha = 0.05). SUBJECTS: Twelve LE (X +/- s.d.; 63.5+/-3.4 y; 1.75+/-0.06 m; 69.01+/-8.24 kg; 20.4+/-4.9 %BF) and 12 LNE (63.6+/-5.6 y; 1.72+/-0.07 m; 79.44 12.4 kg; 29.6 4.4 %BF) were recruited from advertisements placed in a newspaper and on university and community noticeboards. INTERVENTIONS: Measurements were conducted for: RMR using the Douglas bag technique; body composition via a four compartment model which is based on determination of body density, total body water and bone mineral mass; and aerobic fitness using a submaximal work test on a cycle ergometer. RESULTS: The LE (93.00+/-7.16 kJ x kg(-1) x d(-1)) registered a significantly greater (P = 0.04) RMR than the LNE (84.70+/-11.23 kJ x kg(-1) x d(-1)) when energy expenditure was expressed relative to body mass, but this difference disappeared (P = 0.55) when the data were corrected for the non-zero intercept of the graph of RMR (MJ/d) against body mass. ANCOVA with FFM as the covariate also indicated that the RMR (MJ/d) difference between the groups was not statistically significant (P = 0.28). The adjusted means for the LE and LNE were 6.39 and 6.62 MJ/d, respectively. CONCLUSIONS: There are no RMR (MJ/d) differences between LE and LNE 54-71 y old males when statistical control is exerted for the effect of FFM and the higher value of the former group for RMR normalised to body mass disappears when this ratio is corrected for statistical bias.

Energy metabolism in sedentary and active 49- to 70-yr-old women.

This study examined differences between long-term exercising (LE) and long-term nonexercising (LNE) women [n = 24; age 56.4 +/- 6.2 (SD) yr] for resting metabolic rate (RMR) and energy expenditure in the free-living state by using doubly labeled water (DLW). There was a statistically significant difference (P = 0.0002) between the 12 LE (94.85 +/- 8.44 kJ . kg-1 . day-1) and 12 LNE (81.16 +/- 6.62 kJ . kg-1 . day-1) for RMR, but this difference was only marginally significant (P = 0.06) when the data (MJ/day) were subjected to an analysis of covariance with fat-free mass as the covariate. The DLW data indicated that the eight most active LE (12.99 +/- 3.58 MJ/day) expended significantly (P = 0.01) more energy than did the eight least active LNE (9.30 +/- 1.15 MJ/day). Energy expenditures ranged from 7.64 to 18.15 MJ/day, but there was no difference (P = 0.96) between the LE and LNE in energy expenditure during activity that was not designed to either improve or maintain fitness. These cross-sectional data on 49- to 70-yr-old women therefore suggest that 1) aerobic-type training results in a greater RMR per unit of body mass and also when statistical control is exerted for the effect of the metabolically active fat-free mass, 2) there is a large range in the energy intake necessary to maintain energy balance, and 3) aerobic training does not result in a compensatory reduction in energy expenditure during the remainder of the day.

Effect of pollination on accumulation of ACC synthase and ACC oxidase transcripts, ethylene production and flower petal abscission in geranium (Pelargonium x hortorum L.H. Bailey).

Self-pollination of diploid zonal geranium (Pelargonium x hortorum L.H. Bailey) florets leads to a dramatic rise in ethylene production, followed by abscission within 4 h. Neither wounding of the stigma, pollination with tetraploid pollen, nor heat-killed self pollen could elicit as much ethylene production and petal abscission as self-pollination. A cDNA sharing sequence identity with ACC synthase (GACS2) and three different cDNAs sharing sequence identity with ACC oxidase (GACO1, GACO2, GACO3) were isolated from geranium pistils. Transcripts hybridizing with these probes increased slightly in response to self-pollination, but the degree of accumulation in response to various treatments did not correlate with ethylene production. When calculated on a per-plant-part basis, transcripts hybridizing with GACS2 were equally distributed among the stigma+style, sterile ovary, and ovary tissues, but transcripts hybridizing with the three ACC oxidase clones were differentially distributed. All transcripts were differentially expressed among the other tissues of the plant, with GACO1 being the most widely distributed. Ethylene production in geranium pistils was not autocatalytic. Propylene failed to induce ethylene production and ethylene did not induce the accumulation of ACC synthase or ACC oxidase transcripts. ACC accumulated in the stigma and style, and to a smaller extent in the sterile ovary, after pollination. These data support a model of pollination-induced ethylene production by post-transcriptional regulation of ethylene biosynthetic gene expression.

A dominant mutant receptor from Arabidopsis confers ethylene insensitivity in heterologous plants.

Ethylene (C2H4) is a gaseous hormone that affects many aspects of plant growth and development. Ethylene perception requires specific receptors and a signal transduction pathway to coordinate downstream responses. The etr1-1 gene of Arabidopsis encodes a mutated receptor that confers dominant ethylene insensitivity. Evidence is presented here that etr1-1 also causes significant delays in fruit ripening, flower sensecence; and flower abscission when expressed in tomato and petunia plants. The ability of etr1-1 to function in heterologous plants suggests that this pathway of hormone recognition and response is highly conserved and can be manipulated.

Relationship between maximum aerobic power and resting metabolic rate in young adult women.

The literature is inconclusive as to the chronic effect of aerobic exercise on resting metabolic rate (RMR), and furthermore there is a scarcity of data on young women. Thirty-four young women exhibiting a wide range of aerobic fitness [maximum aerobic power (VO2max) = 32.3-64.8 ml.kg-1.min-1] were accordingly measured for RMR by the Douglas bag method, treadmill VO2max, and fat-free mass (FFM) by using Siri's three-compartment model. The interclass correlation (n = 34) between RMR (kJ/h) and VO2max (ml.kg-1.min-1) was significant (r = 0.39, P < 0.05). However, this relationship lost statistical significance when RMR was indexed to FFM and when partial correlation analysis was used to control for FFM differences. Furthermore, multiple linear-regression analysis indicated that only FFM emerged as a significant predictor of RMR (kJ/h). When high- (n = 12) and low-fitness (n = 12) groups were extracted from the cohort on the basis of VO2max scores, independent t-tests revealed significant between-group differences (P < 0.05) for RMR (kJ.kg-1.h-1) and VO2max (ml.kg-1.min-1) but not for RMR (kJ/h), RMR (kJ.kg FFM-1.h-1), and FFM. Analysis of covariance of RMR (kJ/h) with FFM as the covariate also showed no significant difference (P = 0.56) between high- and low-fitness groups. Thus the results suggest that 1) FFM accounts for most of the differences in RMR between subjects of varying VO2max values and 2) the RMR per unit of FFM in young healthy women is unrelated to VO2max.

Differences in substrate metabolism between self-perceived 'large-eating' and 'small-eating' women.

OBJECTIVE: To compare different aspects of intermediary metabolism in self perceived 'small-eating' females and self-perceived near normal weight 'large-eating' females and relate the data to those reported for Pima Indians who have the world's highest prevalence of non-insulin dependent diabetes mellitus and obesity. DESIGN: Make repeat measurements of rates of oxygen consumption, carbon dioxide production and blood metabolites in 'large-' and 'small-eating' females at rest, during different activities and after ingestion of a standardised liquid meal. SUBJECTS: Nine self perceived, 'large-eating' females and nine self perceived 'small-eating' females. MEASUREMENTS: Resting metabolic rates (RMR), respiratory quotient (RQ) values and plasma insulin, glucagon insulin-like growth factor (IGF-1), dehydroepiandrosterone sulphate (DHEA-SO4) and glucose. RESULTS: RMR (adjusted for FFM) averaged 3891 +/- 93 J/min in the 'small-eaters' and 3375 +/- 107 J/min in the 'large-eaters' for ten consecutive measurements conducted at 30 min intervals during the control period for the measurement of the thermic effect of food. Over this period the average RQ for the 'small-eating' women (0.81) was significantly greater than that of the 'large-eating' women (0.78). The two groups responded similarly to an oral glucose tolerance test but the concentration of DHEA-SO4 in plasma was 35% higher in the 'small-eaters'. CONCLUSION: The 'small-eating' women may have a greater risk of weight gain but they counteract this tendency by maintaining high activity levels.

The contribution of glucose cycling to the maintenance of steady-state levels of lactate by hepatocytes during glycolysis and gluconeogenesis.

When hepatocytes from fasted rats were incubated with 10 mM glucose, there was a linear accumulation of lactate and pyruvate for about 80 min after which steady-state concentrations of these metabolites became established. The rate of glycolysis, determined with [6-3H]glucose, was constant over the entire incubation period and was 50% greater than that calculated from carbon balance studies. This suggests that one-third of the glycolytic products formed were recycled to glucose. To enable study of the factors associated with the generation and maintenance of the lactate steady state and to measure accurately the carbon balance, incubations were performed using supraphysiological concentrations of glucose (20-80 mM). Under these conditions the initial rate of lactate accumulation and its concentration at steady state were shown to be dependent on the concentration of extracellular glucose. Rates of glycolysis were also measured using 40 mM [6-3H]glucose and [U-14C]glucose added alone, or in combination with a steady-state lactate concentration (3 mM). There was no effect on the rate of glycolysis determine with [6-3H]glucose, even when lactate was present in the medium. The difference in rates between measurements with the two isotopes reflect the apparent degree of glucose recycling which in the absence and presence of added lactate increased from 0.26 to 0.54 mumol C3 equivalents min-1.g-1 respectively. Identical studies employing [U-14C]lactate showed that glucose and CO2 were the major products of lactate metabolism under steady-state conditions and that the formation of lactate from [U-14C]glucose exactly balanced the rate of lactate removal as a result of oxidation and gluconeogenesis. These studies provide evidence for the concomitant operation of glycolysis and gluconeogenesis, even in the presence of high glucose concentrations. They also demonstrate that lactate steady states are achieved not by the cessation of glycolysis but rather by the removal of lactate and pyruvate at a rate equal to that of their production.

Barriers to the acceptance of in vitro alternatives.

UNLABELLED: Despite a considerable effort by the scientific community over many years, the replacement of traditional animal tests by in vitro alternatives has not yet been achieved. Why are in vitro alternatives not more widely accepted by scientists and regulators? Barriers to acceptance, both overt and covert, must be recognized and surmounted if further progress is to be made. At least seven barriers to acceptance of an in vitro method will be discussed. VALIDATION: has it been adequately validated? Scientific: is it based on good science? Legislative: can it replace an OECD Guideline? DEVELOPMENT: has it been developed in another laboratory? Psychological: will it make traditional skills redundant? Litigation: will it stand up to legal scrutiny in court? Regulatory: will regulators modify their traditional hazard assessment criteria?

US-guided automated large-core breast biopsy.

To evaluate the efficacy of ultrasound (US)-guided automated large-core percutaneous needle breast biopsy, biopsy of 181 ultrasonographically suspicious breast lesions was performed by using a long-throw biopsy gun and 14-gauge needles with continuous US guidance. A "freehand" technique with either 5.0- or 7.5-MHz linear-array transducers was used. Needle core diagnoses were compared with surgical diagnoses in the 49 lesions subsequently surgically excised. The remaining 132 cases were followed for 12-36 months. Agreement between needle-core and surgical diagnoses in the 49 lesions was 100%. This group included 34 cancers (28 infiltrating ductal, two mucinous, one mixed infiltrating ductal and lobular, and one each of intraductal, infiltrating lobular, and tubular carcinoma). To date, no cancers have been found in the other 132 cases. The procedure time averaged 20 minutes, and no complications occurred. With an accuracy approaching that of excisional biopsy, US-guided needle core biopsy provides an alternative to surgery.

Effects of fatty acid oxidation on glucose utilization by isolated hepatocytes.

We have studied the inhibitory action of long- and short-chain fatty acids on hepatic glucose utilization in hepatocytes isolated from fasted rats. The rates of hepatic glucose phosphorylation and glycolysis were determined from the tritiated products of [2-3H] and [6-3H]glucose metabolism, respectively. The difference between these was taken as an estimate of the 'cycling' between glucose and glucose-6-phosphate. In the presence of 40 mM glucose this cycling was estimated at 0.68 mumol/min/g wet wt. Glucose phosphorylation was unaffected during palmitate and hexanoate oxidation to ketone bodies but glycolysis was inhibited. The rate of glucose cycling was increased during this phase to 1.25 mumol/min/g. Following the complete metabolism of the fatty acids, glycolysis was reinstated and cycling rates returned to control levels. Hepatic glucose cycling appears to be an important component of the glucose/fatty acid cycle.

No differences in rates of energy expenditure between post-obese women and their matched, lean controls.

Rates of energy expenditure at rest, during different daily activities and following a standardized liquid meal were compared in eight post-obese women, with a mean weight loss of 21.5 kg (range 14.1 to 33.3 kg) and eight controls who had never been overweight. Age, height, body mass index, fat-free mass and average daily energy intake were similar for both experimental groups. Resting metabolic rate averaged 23.04 cal/min/kg FFM (s.e.m. 1.14) in the post-obese and 22.70 cal/min/kg FFM (s.e.m. 0.64) in the controls on their first visit to the laboratory. Metabolic rates in the two groups rose in parallel as energy expenditure was increased by sitting, standing and walking at three different speeds (2.4, 3.9 and 5.4 km/h). At the highest walking speed energy expenditure averaged 95.30 cal/min/kg FFM (s.e.m. 4.18) in the post-obese and 93.42 cal/min/kg FFM (s.e.m. 2.97) in the control women. Comparisons of postprandial thermogenesis revealed no significant differences between the two groups. The results of the present study do not support the thesis that rates of energy expenditure, whether at rest, during different activities, or after eating, are reduced in post-obese women.

Muscle metabolism during 30, 60 and 90 s of maximal cycling on an air-braked ergometer.

This study examined the anaerobic and aerobic contributions to muscle metabolism during high intensity short duration exercise. Six males [mean (SD): age 25.0 (6.0) years, height 179.0 (8.2) cm, mass 70.01 (7.42) kg, VO2max 4.63 (0.53) l.min-1, body fat 12.7 (2.3)%] performed three counterbalanced treatments of 30, 60 and 90 s of maximal cycling on an air-braked ergometer. All treatments were also performed on days when biopsies were not taken from the vastus lateralis muscle and cannulae not inserted into a forearm vein to ascertain whether these procedures adversely affected performance. The mean results can be summarised as follows: (Table: see text). The muscle lactate and O2 deficit data suggested that 60 and 90 s were more appropriate durations than 30 s for assessing the anaerobic capacity on an air-braked cycle ergometer. The mean power outputs also indicated that the invasive procedures did not adversely affect performance [corrected].