71 research outputs found
A False Start in the Race Against Doping in Sport: Concerns With Cycling’s Biological Passport
Professional cycling has suffered from a number of doping scandals. The sport’s governing bodies have responded by implementing an aggressive new antidoping program known as the biological passport. Cycling’s biological passport marks a departure from traditional antidoping efforts, which have focused on directly detecting prohibited substances in a cyclist’s system. Instead, the biological passport tracks biological variables in a cyclist’s blood and urine over time, monitoring for fluctuations that are thought to indirectly reveal the effects of doping. Although this method of indirect detection is promising, it also raises serious legal and scientific concerns. Since its introduction, the cycling community has debated the reliability of indirect biological-passport evidence and the clarity, consistency, and transparency of its use in proving doping violations. Such uncertainty undermines the legitimacy of finding cyclists guilty of doping based on this indirect evidence alone. Antidoping authorities should address these important concerns before continuing to pursue doping sanctions against cyclists solely on the basis of their biological passports
Body fat mass and the proportion of very large adipocytes in pregnant women are associated with gestational insulin resistance.
Pregnancy is accompanied by fat gain and insulin resistance. Changes in adipose tissue morphology and function during pregnancy and factors contributing to gestational insulin resistance are incompletely known. We sought to characterize adipose tissue in trimesters 1 and 3 (T1/T3) in normal weight (NW) and obese pregnant women, and identify adipose tissue-related factors associated with gestational insulin resistance
Dynamics and Regulation of RecA Polymerization and De-Polymerization on Double-Stranded DNA
10.1371/journal.pone.0066712PLoS ONE86
Pancreatic cancerrelated cachexia: influence on metabolism and correlation to weight loss and pulmonary function
<p>Abstract</p> <p>Background</p> <p>Dramatic weight loss is an often underestimated symptom in pancreatic cancer patients. Cachexia- defined as an unintended loss of stable weight exceeding 10% – is present in up to 80% of patients with cancer of the upper gastrointestinal tract, and has a significant influence on survival. The aim of the study was to show the multiple systemic effects of cachexia in pancreatic cancer patients, in terms of resection rate, effects on pulmonary function, amount of fat and muscle tissue, as well as changes in laboratory parameters.</p> <p>Methods</p> <p>In patients with pancreatic cancer, clinical appearance was documented, including the amount of weight loss. Laboratory parameters and lung-function tests were evaluated, and the thickness of muscle and fat tissue was measured with computed tomography scans. Statistical analysis, including multivariate analysis, was performed using SPSS software. Survival curves were calculated using Kaplan-Meier analysis and the log-rank test. To test for significant differences between the examined groups we used Student's t-test and the Mann-Whitney U test. Significance was defined as p < 0.05.</p> <p>Results</p> <p>Of 198 patients with a ductal adenocarcinoma of the pancreas, 70% were suffering from weight loss when they presented for operation, and in 40% weight loss exceeded 10% of the stable weight. In patients with cachexia, metastases were diagnosed significantly more often (47% vs. 24%, P < 0.001), leading to a significantly reduced resection rate in these patients. Patients with cachexia had significantly reduced fat tissue amounts. Hence, dramatic weight loss in a patient with pancreatic cancer may be a hint of a more progressed or more aggressive tumour.</p> <p>Conclusion</p> <p>Pancreatic cancer patients with cachexia had a higher rate of more progressed tumour stages and a worse nutritional status. Furthermore, patients with cachexia had an impaired lung function and a reduction in fat tissue. Patients with pancreatic cancer and cachexia had significantly reduced survival. If weight loss exceeded 5% there was a significantly reduced resection rate to detect, but the changes were significantly more substantial if weight loss was 10% or more. We propose that a weight loss of 10% be defined as significant in pancreatic cancer.</p
Adipose tissue pathways involved in weight loss of cancer cachexia
White adipose tissue (WAT) constitutes our most expandable tissue and largest
endocrine organ secreting hundreds of polypeptides collectively termed adipokines.
Changes in WAT mass induce alterations in adipocyte secretion and function, which
are linked to disturbed whole-body metabolism. Although the mechanisms controlling
this are not clear they are dependent on changes in gene expression, a complex process
which is regulated at several levels. Results in recent years have highlighted the role of
small non-coding RNA molecules termed microRNAs (miRNAs), which regulate gene
expression via post-transcriptional mechanisms. The aim of this thesis was to
characterize global gene expression levels and describe novel miRNAs and adipokines
controlling the function of human WAT in conditions with pathological increases or
decreases in WAT mass. Obesity and cancer cachexia were selected as two models
since they are both clinically relevant and characterized by involuntary changes in
WAT mass.
In Study I, expressional analyses were performed in subcutaneous WAT from cancer
patients with or without cachexia and obese versus non-obese subjects. In total, 425
transcripts were found to be regulated in cancer cachexia. Pathway analyses based on
this set of genes revealed that processes involving extracellular matrix, actin
cytoskeleton and focal adhesion were significantly downregulated, whereas fatty acid
metabolism was upregulated comparing cachectic with weight-stable cancer subjects.
Furthermore, by overlapping these results with microarray data from an obesity study,
many transcripts were found to be reciprocally regulated comparing the two conditions.
This suggests that WAT gene expression in cancer cachexia and obesity are regulated
by similar, albeit opposing, mechanisms.
In Study II, the focus was on the family of
fibroblast growth factors (FGFs), members of which have recently been implicated in
the development of obesity and insulin resistance. A retrospective analysis of global
gene expression data identified several FGFs (FGF1/2/7/9/13/18) to be expressed in
WAT. However, only one, FGF1, was actively secreted from WAT and predominantly
so from the adipocyte fraction. Moreover, FGF1 release was increased in obese
compared to non-obese subjects, but was not normalized by weight loss. Although the
clinical significance of these findings is not yet clear, it can be hypothesized that FGF1
may play a role in WAT growth, possibly by promoting fat cell proliferation and/or
differentiation.
In Study III, we identified adipose miRNAs regulated in obesity. Out
of eleven miRNAs regulated by changes in body fat mass, ten controlled the production
of the pro-inflammatory chemoattractant chemokine (C-C motif) ligand 2 (CCL2)
when overexpressed in fat cells and for two, miR-126 and -193b, signaling circuits
were defined.
In Study IV, a novel adipokine, semaphorin 3C (SEMA3C), was
identified by combining transcriptome and secretome data. Detailed studies focusing on
SEMA3C revealed that this factor was secreted from adipocytes and induced the
expression of extracellular matrix and matricellular genes in preadipocytes.
Furthermore, SEMA3C mRNA levels correlated with interstitial fibrosis and insulin
resistance in WAT derived from subjects with a wide range in BMI.
In summary, the results presented in this thesis have delineated transcriptional
alterations in WAT in two clinically relevant conditions, obesity and cancer cachexia.
This has allowed the identification of novel adipokines and microRNAs with potential
pathophysiological importance. These findings form the basis for further studies aiming
at understanding the central role of WAT in disorders associated with metabolic
complications
Determination of Inactive Powers in a Single-Phase AC Network
Based on the development of the theory of reactive power and distortion power, starting with the works of Fryze and Budeanu, it has been found that the contradictions in the definition of the components of inactive powers are caused by errors in the introduced intermediate concepts and corresponding calculations when switching to nonlinear and non-sinusoidal AC circuits. The materials of the works of modern researchers and the numerical calculations carried out made it possible to trace the differences between reactive power and distortion power, to confirm the orthogonality properties of the active, reactive power, and distortion power components. The paper defines the conditions for achieving a power balance in an AC network with nonlinear loads, compiled and tested criteria leading to the absence of distortion power in a single-phase AC network. Using the time base of the projection of the generalized vectors in vector diagrams, it is shown that compliance with the criteria for the absence of distortion power does not determine the mutual similarity of the voltage curve with the current curve for a nonlinear load. It has been found that the well-known term “distortion power” has an unfortunate wording, since this power, although it characterizes the interaction of harmonics of currents and voltages with different ordinal numbers, is not determined by the visual similarity or the degree of distortion of the load current waveforms relative to the supply voltage curve
Novel essential amino acid supplements enriched with L-leucine facilitate increased protein and energy intakes in older women: a randomised controlled trial
Background: Inadequate protein intake (PI), containing a sub-optimal source of essential amino acids (EAAs), and reduced appetite are contributing factors to age-related sarcopenia. The satiating effects of dietary protein per se may negatively affect energy intake (EI), thus there is a need to explore alternative strategies to facilitate PI without compromising appetite and subsequent EI. Methods: Older women completed two experiments (EXP1 and EXP2) where they consumed either a Bar (565 kJ), a Gel (477 kJ), both rich in EAAs (7.5 g, 40% L-leucine), or nothing (Control). In EXP1, participants (n=10, 68±5 years, mean±SD) consumed Bar, Gel or Control with appetite sensations and appetite-related hormonal responses monitored for one hour, followed by consumption of an ad libitum breakfast (ALB). In EXP2, participants (n=11, 69±5 years) ingested Bar, Gel or Control alongside an ALB. Results: In EXP1, EI at ALB was not different (P=0.674) between conditions (1179±566, 1254±511, 1206±550 kJ for the Control, Bar, and Gel respectively). However, total EI was significantly higher in the Bar and Gel compared to the Control after accounting for the energy content of the supplements (P<0.0005). Analysis revealed significantly higher appetite Area under the Curve (AUC) (P<0.007), a tendency for higher acylated ghrelin AUC (P=0.087), and significantly lower pancreatic polypeptide AUC (P=0.02) in the Control compared with the Bar and Gel. In EXP2, EI at ALB was significantly higher (P=0.028) in the Control (1282±513 kJ) compared to the Bar (1026±565 kJ) and Gel (1064±495 kJ). However, total EI was significantly higher in the Bar and Gel after accounting for the energy content of the supplements (P<0.007). Conclusions: Supplementation with either the Bar or Gel increased total energy intake whether consumed one hour before or during breakfast. This may represent an effective nutritional means for addressing protein and total energy deficiencies in older women
Modeling the energetic cost of cancer as a result of altered energy metabolism: implications for cachexia
A prospective investigation of swallowing, nutrition, and patient-rated functional impact following altered fractionation radiotherapy with concomitant boost for oropharyngeal cancer
Altered fractionation radiotherapy for head and neck cancer has been associated with improved locoregional control, overall survival, and heightened toxicity compared with conventional treatment. Swallowing, nutrition, and patient-perceived function for altered fractionation radiotherapy with concomitant boost (AFRT-CB) for T1–T3 oropharyngeal squamous cell carcinoma (SCC) have not been previously reported. Fourteen consecutive patients treated with AFRT-CB for oropharyngeal SCC were recruited from November 2006 to August 2009 in a tertiary hospital in Brisbane, Australia. Swallowing, nutrition, and patient-perceived functional impact assessments were conducted pretreatment, at 4–6 weeks post-treatment, and at 6 months post-treatment. Deterioration from pretreatment to 4–6 weeks post-treatment in swallowing, nutrition, and functional impact was evident, likely due to the heightened toxicity associated with AFRT-CB. There was significant improvement at 6 months post-treatment in functional swallowing, nutritional status, patient-perceived swallowing, and overall function, consistent with recovery from acute toxicity. However, weight and patient perception of physical function and side effects remained significantly worse than pretreatment scores. The ongoing deficits related to weight and patient-perceived outcomes at 6 months revealed that this treatment has a long-term impact on function possibly related to the chronic effects of AFRT-CB
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