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1.
Team-based internet interventions are increasing in popularity as a way of promoting weight loss in large numbers of individuals. Given that social networks influence health behavior change, this study investigated the effects of teammates and social influence on individual weight loss during a team-based weight loss competition. Shape Up Rhode Island (SURI) 2009 was a 12-week online program open to adult residents of Rhode Island. Participants joined with a team and competed with other teams on weight loss and/or physical activity. Overweight/obese (OW/OB) individuals (N = 3,330; 76% female; age = 46.1 ± 10.8; BMI = 31.2 ± 5.3 kg/m(2)), representing 987 teams, completed the weight loss program. Multilevel modeling was used to examine whether weight loss clustered among teammates and whether percentage of teammates in the weight loss division and reported teammate influence on weight loss were associated with individual weight outcomes. OW/OB completers reported losing 4.2 ± 3.4% of initial body weight. Weight loss was similar among teammates (intraclass correlation coefficient (ICC) = 0.10, P < 0.001). Moreover, having a greater percentage of teammates in the weight loss division and reporting higher social influence for weight loss were associated with greater percent weight loss (P's ≤ 0.002). Similarly, achieving a clinically significant (5%) weight loss tended to cluster within teams (ICC = 0.09; P < 0.001) and having more teammates in the weight loss division and higher social influence for weight loss were associated with increased likelihood of achieving a 5% weight loss (odds ratio (OR) = 1.06; OR = 1.20, respectively). These results suggest that teammates affect weight loss outcomes during a team-based intervention. Harnessing and maximizing teammate influence for weight loss may enhance weight outcomes in large-scale team-based programs.  相似文献   

2.
Drosophila melanogaster males carrying either a ring- or a rod-shaped X-chromosome were injected or fed with Trenimon (triaziquone) at concentrations ranging from 5 X 10(-5) to 2 X 10(-2) mM. The F1 generation was assayed for the occurrence of total sex chromosome loss and of Y-chromosome markers. Sex-linked recessive lethal tests were carried out simultaneously. The data show that significant induction of ring-X loss occurs already at very low treatment concentrations (5 X 10(-5) -10(-4) mM) whereas rod-X loss or Y-marker loss is only seen at 2-5 X 10(-3) mM and higher. Induction of sex-linked recessive lethals is observed from 10(-4) -10(-3) mM on. These results add to existing evidence that loss of ring-X chromosomes, induced by some chemicals, may proceed by a mechanism different from the kind of events leading to chromosome breakage, as measured by rod-X loss and Y-marker loss.  相似文献   

3.
Although weight loss ameliorates many of the metabolic abnormalities associated with obesity, there has been reluctance to prescribe weight loss in obese, older individuals because of the fear that it will cause debilitating loss of muscle mass and impair physical function. To gain insight into the mechanisms responsible for the weight loss-induced changes in muscle mass, we measured the rate of muscle protein synthesis (by using stable isotope labeled tracer methodology) during basal, postabsorptive conditions and during mixed meal ingestion in eight obese, older adults: (i) before weight loss therapy, (ii) ~3 months after starting the weight loss intervention (i.e., during the active weight loss phase), when subjects had lost ~7% of their initial body weight, and (iii) after they had lost ~10% of their body weight and maintained this new body weight for ~6 months (~12 months after starting the weight loss intervention). The basal muscle protein fractional synthesis rate (FSR) was not affected by weight loss. Mixed meal ingestion stimulated the rate of muscle protein synthesis, and the anabolic response (i.e., increase in the protein synthesis rate above basal values) was greater (P < 0.05) during negative energy balance and active weight loss at 3 months (0.033 ± 0.012%·per hour, mean ± s.e.m.) than during weight maintenance before and at 12 months of weight loss therapy (0.003 ± 0.003 and 0.008 ± 0.012%·per hour, respectively). We conclude that during dietary calorie restriction and weight loss in older adults, the rate of muscle protein synthesis is not impaired. Thus, the loss of muscle mass must be mediated predominately by adverse effects of dietary calorie restriction on muscle proteolysis.  相似文献   

4.
Pregnancy rates, length of interovulatory intervals, and progesterone concentrations were examined in mares which had ultrasonically detected collections of fluid in the uterine lumen and in mares which lost the embryonic vesicle during Days 11 to 15 and did not become pseudopregnant. In mares with embryonic loss, the loss rate for mares with re-established pregnancies (9 18 ) was greater (P<0.05) than the loss rate for all pregnancies (38 154 ), indicating repeatability. Pregnancy rates were higher (P<0.01) in controls (100 177 ) than in mares with intrauterine fluid collections (2 34 ) or mares with embryonic loss (10 33 ), excluding the pregnancy associated with embryonic loss. The mean length (days) of the interovulatory interval was reduced (P<0.05) in mares with intrauterine fluid collections (20.4 +/-0.9) and in mares with embryonic loss both for the intervals in which loss occurred (19.6 +/-0.7) and for intervals in which pregnancy was not detected (21.0 +/-1.0; controls, 23.5 +/-0.6). Mean progesterone concentration (ng/ml) on Day 7 was lower (P<0.05) in mares with intrauterine fluid collections (8.8 +/-1.8) and in mares with embryonic loss (12.1 +/-1.1) than in pregnant controls (17.2 +/-0.9) and nonpregnant controls (17.5 +/-0.1). The embryonic loss seemed attributable to uterine-induced luteolysis in association with uterine inflammation, but the possibility of involvement of a primary luteal inadequacy or other factors in at least some of the mares was not eliminated.  相似文献   

5.
The role of lysosomes in exercise-induced hepatic protein loss.   总被引:4,自引:1,他引:3       下载免费PDF全文
Previous reports have shown that exercise causes a loss of liver protein. The purpose of the present study was to elucidate the mechanism of this exercise-induced protein loss. Exercise caused: (1) an increase in mechanical and osmotic lysosomal fragility; (2) a significant loss of hepatic water, glycogen, protein, phospholipid and RNA; (3) loss of protein from the soluble, mitochondrial and microsomal fractions: (4) loss of mitochondrial, microsomal and cytosolic, but not lysosomal, enzyme activity; (5) an increase in the number of autophagic vacuoles; (6) an increase in the lysosomal size. Taken together, these results suggest that the autophagolysosomal system is responsible for the exercise-induced hepatic protein loss.  相似文献   

6.
The purpose of this study was to investigate weight loss expectations and goals in a population sample of US adults who planned to make a weight loss attempt, and to examine predictors of those expectations and goals. Participants were 658 overweight and obese adults (55% women, mean age = 47.9 years, BMI = 31.8 kg/m(2)) who responded to a telephone survey about weight loss. Respondents reported weight loss expectations (i.e., reductions they realistically expected) and goals (i.e., reductions they ideally desired) for an upcoming "serious and deliberate" weight loss attempt. They also reported the expectations they had, and the reductions they actually achieved, in a previous attempt. Respondents' weight loss expectations for their upcoming attempt (8.0% reduction in initial weight) were significantly more modest than their goals for that attempt (16.8%), and smaller than the losses that they expected (12.0%), and achieved (8.9%) in their most recent past attempt (Ps 相似文献   

7.
To understand the role of fruit cuticle lipid composition in fruit water loss, an advanced backcross population, the BC(2)F(2) , was created between the Capsicum annuum (PI1154) and the Capsicum chinense (USDA162), which have high and low post-harvest water loss rates, respectively. Besides dramatic differences in fruit water loss, preliminary studies also revealed that these parents exhibited significant differences in both the amount and composition of their fruit cuticle. Cuticle analysis of the BC(2)F(2) fruit revealed that although water loss rate was not strongly associated with the total surface wax amount, there were significant correlations between water loss rate and cuticle composition. We found a positive correlation between water loss rate and the amount of total triterpenoid plus sterol compounds, and negative correlations between water loss and the alkane to triterpenoid plus sterol ratio. We also report negative correlations between water loss rate and the proportion of both alkanes and aliphatics to total surface wax amount. For the first time, we report significant correlations between water loss and cutin monomer composition. We found positive associations of water loss rate with the total cutin, total C(16) monomers and 16-dihydroxy hexadecanoic acid. Our results support the hypothesis that simple straight-chain aliphatic cuticle constituents form more impermeable cuticular barriers than more complex isoprenoid-based compounds. These results shed new light on the biochemical basis for cuticle involvement in fruit water loss.  相似文献   

8.
Little is known about the transition in behaviors from short-term weight loss to maintenance of weight loss. We wanted to determine how short-term and long-term weight loss and patterns of weight change were associated with intervention behavioral targets. This analysis includes overweight/obese participants in active treatment (n = 507) from the previously published PREMIER trial, an 18-month, multicomponent lifestyle intervention for blood pressure reduction, including 33 intervention sessions and recommendations to self-monitor food intake and physical activity daily. Associations between behaviors (attendance, recorded days/week of physical activity, food records/week) and weight loss of ≥5% at 6 and 18 months were examined using logistic regression. We characterized the sample using 5 weight change categories (weight gained, weight stable, weight loss then relapse, late weight loss, and weight loss then maintenance) and analyzed adherence to the behaviors for each category, comparing means with ANOVA. Participants lost an average of 5.3 ± 5.6 kg at 6 months and 4.0 ± 6.7 kg (4.96% of body weight) by 18 months. Higher levels of attendance, food record completion, and recorded days/week of physical activity were associated with increasing odds of achieving 5% weight loss. All weight change groups had declines in the behaviors over time; however, compared to the other four groups, the weight loss/maintenance group (n = 154) had statistically less significant decline in number of food records/week (48%), recorded days/week of physical activity (41.7%), and intervention sessions attended (12.8%) through 18 months. Behaviors associated with short-term weight loss continue to be associated with long-term weight loss, albeit at lower frequencies. Minimizing the decline in these behaviors may be important in achieving long-term weight loss.  相似文献   

9.
Alzheimer disease is characterized by neuronal loss and brain plaques of extracellular amyloid β (Aβ), but the means by which Aβ may induce neuronal loss is not entirely clear. Although high concentrations of Aβ (μM) can induce direct toxicity to neurons, we find that low concentration (nM) induce neuronal loss through a microglia-mediated mechanism. In mixed neuronal-glial cultures from rat cerebellum, 250 nM Aβ1-42 (added as monomers, oligomers or fibers) induced about 30% loss of neurons between 2 and 3 days. This neuronal loss occurred without any increase in neuronal apoptosis or necrosis, and no neuronal loss occurred with Aβ42-1. Aβ greatly increased the phagocytic capacity of microglia and induced phosphatidylserine exposure (an "eat-me" signal) on neuronal processes. Blocking exposed phosphatidylserine by adding annexin V or an antibody to phosphatidylserine or inhibiting microglial phagocytosis by adding either cytochalasin D (to block actin polymerization) or cyclo(RGDfV) (to block vitronectin receptors) significantly prevented neuronal loss. Loss of neuronal synapses occurred in parallel with loss of cell bodies and was also prevented by blocking phagocytosis. Inhibition of phagocytosis prevented neuronal loss with no increase in neuronal death, even after 7 days, suggesting that microglial phagocytosis was the primary cause of neuronal death induced by nanomolar Aβ.  相似文献   

10.
This study presents the first physiological information for a member of the wingless Mantophasmatodea, or Heelwalkers. This species shows cyclic gas exchange with no evidence of a Flutter period (more typical of discontinuous gas exchange in insects) and no indication that the spiracles are fully occluded during quiescent metabolism. Standard metabolic rate at 20 degrees C was 21.32+/-2.73 microl CO(2)h(-1) (mean+/-S.E.), with a Q(10) (10-25 degrees C) of 1.7. Increases in V()CO(2) associated with variation in mass and with trial temperature were modulated by an increase in burst period volume and a decline in cycle frequency. Total water loss rate, determined by infrared gas analysis, was 0.876+/-0.08 mg H(2)Oh(-1) (range 0.602-1.577, n=11) whilst cuticular water loss rate, estimated by linear regression of total water loss rate and metabolic rate, was 0.618+/-0.09 mg H(2)Oh(-1) (range 0.341-1.363, n=11). Respiratory water loss rate was therefore no more than 29% of the total rate of water loss. Both total water loss rate and estimated cuticular water loss rate were significantly repeatable, with intraclass correlation coefficients of 0.745 and 0.553, respectively.  相似文献   

11.
Species–area (SAR) and endemics–area (EAR) relationships are amongst the most common methods used to forecast species loss resulting from habitat loss. One critical, albeit often ignored, limitation of these area‐based estimates is their disregard of the ecological context that shapes species distributions. In this study, we estimate species loss using a spatially explicit mechanistic simulation model to evaluate three important aspects of ecological context: coexistence mechanisms (e.g. species sorting, competition–colonization tradeoffs and neutral dynamics), spatial distribution of environmental conditions, and spatial pattern of habitat loss. We found that 1) area‐based estimates of extinctions are sensitive to coexistence mechanisms as well as to the pattern of environmental heterogeneity; 2) there is a strong interaction between coexistence mechanisms and the pattern of habitat loss; 3) SARs always yield higher estimates of species loss than do EARs; and 4) SARs and EARs consistently underestimate the realized species loss. Our results highlight the need to integrate ecological mechanisms in area‐estimates of species loss.  相似文献   

12.
Congenital human cytomegalovirus (HCMV) occurs in 0.5–1% of live births and approximately 10% of infected infants develop hearing loss. The mechanism(s) of hearing loss remain unknown. We developed a murine model of CMV induced hearing loss in which murine cytomegalovirus (MCMV) infection of newborn mice leads to hematogenous spread of virus to the inner ear, induction of inflammatory responses, and hearing loss. Characteristics of the hearing loss described in infants with congenital HCMV infection were observed including, delayed onset, progressive hearing loss, and unilateral hearing loss in this model and, these characteristics were viral inoculum dependent. Viral antigens were present in the inner ear as were CD3+ mononuclear cells in the spiral ganglion and stria vascularis. Spiral ganglion neuron density was decreased after infection, thus providing a mechanism for hearing loss. The lack of significant inner ear histopathology and persistence of inflammation in cochlea of mice with hearing loss raised the possibility that inflammation was a major component of the mechanism(s) of hearing loss in MCMV infected mice.  相似文献   

13.
To examine the effects of aging on the density and distribution of somatostatin receptors (SS-R) in the rat brain, receptor autoradiography for SS-R was carried out in rats aged 3 and 24 months using 125I-labeled Tyr11-SS-14. Autoradiograms were quantitatively assessed by an image analyzer to evaluate changes in the expression of SS-R due to senescence. Statistically significant decreases in SS-R binding were found in specific regions of the brains of senescent rats as compared to young adult rats. The regions affected included the periaqueductal gray matter (73% loss versus young adult rats), the interpeduncular nucleus (73% loss), the pontine nucleus (63% loss), the superior colliculus (46% loss), the ventral tegmental area (46% loss), the temporal cortex (39% loss), the frontal cortex (34% loss), the hippocampus (33% loss), the amygdala (27% loss) and the claustrum (26% loss). There was no significant change in SS-R expression in the spinal cord with aging. Significant reductions in SS-R binding in these brain regions may be involved in the impairment of sensory and cognitive function that can occur with aging.  相似文献   

14.
Changes in markers of inflammation (MOI) and fat distribution with weight loss between African-American (AA) and white (W) women have yet to be characterized. The purpose of this study was to examine potential ethnic differences in MOI and regional fat distribution with weight loss, and identify the associations between these markers and changes in regional fat distribution with weight loss among AA and W women. Subjects were 126 healthy, premenopausal women, BMI 27-30 kg/m(2). They were placed on a weight-loss intervention consisting of diet and/or exercise until a BMI <25 was achieved. Fat distribution was measured with computed tomography, and body composition with dual-energy X-ray absorptiometry. Serum concentrations of tumor necrosis factor-α (TNF-α), soluble TNF receptor-I (sTNFR-I), sTNFR-II, C-reactive protein (CRP), and interleukin-6 (IL-6) were assessed. All MOI and adiposity measures significantly decreased with weight loss. Significant ethnic differences with weight loss were observed for fat mass, body fat, intra-abdominal adipose tissue (IAAT), sTNFR-I, and sTNFR-II. Mixed-model analysis indicated that adjusting for change in IAAT explained ethnic differences in change in TNF-α and the decrease in TNF-α with weight loss, while total fat mass only explained the decrease in sTNFR-I and sTNFR-II with weight loss. In conclusion, all MOI decreased following weight loss among W, whereas only IL-6 and CRP decreased following weight loss in AA. The most distinct phenotypic difference observed was a greater impact of weight loss on TNF-α in W compared to AA, which was directly associated with IAAT in W.  相似文献   

15.
Although catastrophic weight loss is no longer common in HIV-infected men, we hypothesized that a more gradual process of cachexia [loss of lean body mass (LBM) without severe weight loss, often accompanied by elevated resting energy expenditure (REE)] is still common and is driven by excessive production of the catabolic cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta). We performed a longitudinal analysis of an ongoing cohort study of nutritional status in 172 men with HIV infection. LBM loss of >1 kg occurred in 35% of the cohort, and LBM loss of >5% occurred in 12.2% over 8 mo of observation, but classical wasting (loss of approximately 10% of weight) was rare (2%). Both TNF-alpha (-150 g LBM. ng(-1) x ml(-1), P < 0.02) and IL-1 beta production (-130 g LBM x ng(-1) x ml(-1), P < 0.01) by peripheral blood mononuclear cells predicted loss of LBM. A rise in REE of >200 kcal/day was found in 17.7% of the subjects regardless of weight change. IL-1 beta (+9 kcal/day per ng/ml, P < 0.002) and TNF-alpha (+10 kcal/day per ng/ml, P < 0.02) production predicted Delta REE. Serum free testosterone was inversely associated with TNF-alpha production and was not an independent predictor of either Delta LBM or Delta REE after adjustment for cytokine production. Even though weight loss was rare in this cohort of patients treated with highly active antiretroviral therapy, loss of LBM was common and was driven by catabolic cytokines and not by inadequate dietary intake or hypogonadism.  相似文献   

16.
华南赤红壤无机复合肥氮磷淋失特征   总被引:12,自引:0,他引:12  
采用室内土柱淋溶模拟试验,研究了不同施肥水平下无机复合肥中氮和磷在华南赤红壤中的淋失特征.结果表明: 铵态氮、硝态氮和总氮淋失量均随施肥量增加而提高;肥料中氮的淋失率在36.8%~49.2%之间,总氮淋失量(y)与施肥量(x)之间的回归方程为y=0.3667x+66.483(R2=0.992);铵态氮和总氮的淋失主要集中在前5次淋洗,硝态氮的淋失持续时间更长.施肥量对可溶性磷淋失量无显著影响,但颗粒磷和总磷淋失量均随施肥量增加呈上升趋势;肥料磷淋失率在0.002%~0.010%之间,总磷淋失量(y)与施肥量(x)之间的回归方程为y=7e-5x+0.0538(R2=0.931);磷的淋失动态与氮显著不同,为缓慢的持续累积过程.硝态氮与铵态氮淋失量比值和可溶性磷与颗粒磷淋失量比值均随施肥量增加呈下降趋势.  相似文献   

17.
The present study was designed to establish whether plasma pregnancy-associated glycoprotein-1 (PAG-1) measurements during the early fetal period can be associated with early fetal loss. Blood samples were obtained and ultrasound controls performed on days 35, 42, 49, 56, and 63 of gestation or until pregnancy loss from 98 lactating dairy cows. Radioimmunoassay systems were used to determine PAG-1 and progesterone concentrations. Of the 98 pregnancies investigated 18 (18.4%) suffered early fetal loss: 15 (18.5%) in cows carrying singletons, and 3 (16.7%) in twin pregnancies. In cows suffering pregnancy loss, all living embryos registered on day 35 seemed normal in size and development in all weekly ultrasound controls before fetal expulsion. Using analysis of variance, plasma PAG-1 and progesterone values were not different between no loss and fetal loss groups for every gestation period. Based on the odds ratio, and considering only PAG-1 values obtained on day 35 of gestation, the risk of fetal loss was 10 and 6.8 times more likely in cows with low (<2.5 ng/ml) and high (>4 ng/ml) PAG-1 values, respectively, than in cows with medium PAG-1 values, used as reference. Of the 10 inseminating bulls included in the study, one was related to increased fetal loss by odds ratio of 21.7, whereas one bull was attributed fetal loss rate reduced by odds ratio of 12.5 (1/0.08) These findings can have a clear clinical application: PAG-1 measurements from one single sample taken on day 35 of gestation provided more useful information than a series of values obtained from day 35 to 63 of gestation, and can be indicators of subsequent fetal loss.  相似文献   

18.
Objective: We examined predictors of weight loss with topiramate, an anticonvulsant associated with weight loss in adults. Research Methods and Procedures: In this uncontrolled, prospective clinical trial, topiramate was added to existing anticonvulsants in adults (40 to 110 kg) with partial‐onset seizures. Primary measurements were change from baseline weight after 3 months and 1 year in patients completing 1 year of topiramate treatment (N = 38). Physiological and metabolic measures were analyzed for correlation with weight loss during topiramate treatment. Results: In patients who completed 1 year of topiramate treatment, baseline weight was reduced in 82% at 3 months and in 86% at 1 year. Mean body weight was reduced 3.0 kg (3.9% of baseline) at 3 months and 5.9 kg (7.3%) at 1 year. In obese patients [body mass index (BMI) ≥ 30 kg/m2], mean weight loss was 4.2 kg (4.3%) at 3 months and 10.9 kg (11.0%) at 1 year. Weight loss was primarily caused by reduction in body fat mass. For all patients, weight loss at 3 months correlated most strongly with reduced caloric intake (p = 0.02). At 1 year, caloric intake had returned to baseline levels; weight loss correlated most strongly with higher baseline BMI (p = 0.0007). Discussion: Our results suggest that weight loss occurs in most adults treated with topiramate and is sustained for at least 1 year. Reduced caloric intake may account, in part, for weight loss during early treatment. The pattern of weight loss differs according to baseline BMI, with obese patients experiencing greater weight loss during continued therapy.  相似文献   

19.
The aim of this study was to investigate the interactions of implant position, implant–abutment connection and loading condition influencing bone loss of an implant placed in the maxilla using finite element (FE) analysis and mathematical bone remodeling theory. The maxilla section contours were acquired using CT images to construct FE models containing RS (internal retaining-screw) and the TIS (taper integrated screwed-in) implants placed in SC (along the axis of occlusal force) and RA (along the axis of residual ridge) positions. The adaptive strain energy density (SED) algorithm was combined with FE approach to study the preliminary bone remodeling around implant systems under different load conditions. The simulated results showed that the implant position obviously influenced the bone loss. An implant placed in the RA position resulted in substantially increased bone loss. Implant receiving a lateral load slightly increased bone loss compared with an axial load. The implant type did not significantly influence bone loss. It was found that buccal site suffered the most bone loss around the implant, followed by distal, lingual and mesial sites. The implant position primarily influenced bone loss and it was found most obviously at the buccal site. Implant placed along the axial load direction of a proposed prosthesis could obtain less bone loss around the implant. Attaining proper occlusal adjustments to reduce the lateral occlusal force is recommended in implant–bone–prosthesis system. Abutments of internal engagement with or without taper-fit did not affect the bone loss in the surrounding bone.  相似文献   

20.
ABSTRACT. The marked weight loss that follows adult eclosion in Heliothis zea (Boddie) (Lepidoptera: Noctuidae) was found to be the result of diuresis. This diuretic weight loss amounted to 18.2% of the emergence weight in females and 22.5% in males. Ligation between head and thorax immediately following emergence resulted in a significant reduction in this weight loss. Injection of homogenates of brain (BR) or suboesophageal ganglion (SOG) partially restored the weight loss in ligated insects, indicating potential neurohormonal regulation of this phenomenon.
Because injection of homogenates of nervous and neuroendocrine tissues other than BR and SOG did not result in increased weight loss over controls, the activity present in BR and SOG was probably a tissue-specific phenomenon. We speculate that a factor at least partially responsible for the enhanced diuretic weight loss is present in the fused BR/SOG.  相似文献   

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