651 research outputs found
PERFORMANCE DETERMINING FACTORS IN ELITE SPRINTERS DURING SPRINT START AND TWO FOLLOWING SUCCESSIVE SUPPORTS
Sprint start out of the blocks and successive acceleration are technically challenging as the athlete goes from a bended to a forward leaning position. Therefore, the body center of mass (COM) has to be accelerated forward and upwards. Optimal sprinting performance relies on attaining maximal forward acceleration. However, adequate vertical acceleration must be generated to reach sufficient height to prepare for the following step (Weyand, 2000). Horizontal acceleration is mainly determined by the horizontal ground reaction force that will affect sprint velocity and therefore final sprint performance (Mero, 1988). Kinematics and kinetics of the start action and maximal sprinting were intensively studied; however little is known on the transition from the set position to the running position during the first two strides. This study aims to identify the factors in the start action as well as in the first and second contact after block clearance that determine sprinting performance in terms of speed and acceleration
HAM-5 functions as a MAP kinase scaffold during cell fusion in Neurospora crassa.
Cell fusion in genetically identical Neurospora crassa germlings and in hyphae is a highly regulated process involving the activation of a conserved MAP kinase cascade that includes NRC-1, MEK-2 and MAK-2. During chemotrophic growth in germlings, the MAP kinase cascade members localize to conidial anastomosis tube (CAT) tips every ∼8 minutes, perfectly out of phase with another protein that is recruited to the tip: SOFT, a recently identified scaffold for the MAK-1 MAP kinase pathway in Sordaria macrospora. How the MAK-2 oscillation process is initiated, maintained and what proteins regulate the MAP kinase cascade is currently unclear. A global phosphoproteomics approach using an allele of mak-2 (mak-2Q100G) that can be specifically inhibited by the ATP analog 1NM-PP1 was utilized to identify MAK-2 kinase targets in germlings that were potentially involved in this process. One such putative target was HAM-5, a protein of unknown biochemical function. Previously, Δham-5 mutants were shown to be deficient for hyphal fusion. Here we show that HAM-5-GFP co-localized with NRC-1, MEK-2 and MAK-2 and oscillated with identical dynamics from the cytoplasm to CAT tips during chemotropic interactions. In the Δmak-2 strain, HAM-5-GFP localized to punctate complexes that did not oscillate, but still localized to the germling tip, suggesting that MAK-2 activity influences HAM-5 function/localization. However, MAK-2-GFP showed cytoplasmic and nuclear localization in a Δham-5 strain and did not localize to puncta. Via co-immunoprecipitation experiments, HAM-5 was shown to physically interact with NRC-1, MEK-2 and MAK-2, suggesting that it functions as a scaffold/transport hub for the MAP kinase cascade members for oscillation and chemotropic interactions during germling and hyphal fusion in N. crassa. The identification of HAM-5 as a scaffold-like protein will help to link the activation of MAK-2 cascade to upstream factors and proteins involved in this intriguing process of fungal communication
Wheat amylase/trypsin inhibitors (ATIs): occurrence, function and health aspects
Amylase/trypsin inhibitors (ATIs) are widely consumed in cereal-based foods and have been implicated in adverse reactions to wheat exposure, such as respiratory and food allergy, and intestinal responses associated with coeliac disease and non-coeliac wheat sensitivity. ATIs occur in multiple isoforms which differ in the amounts present in different types of wheat (including ancient and modern ones). Measuring ATIs and their isoforms is an analytical challenge as is their isolation for use in studies addressing their potential effects on the human body. ATI isoforms differ in their spectrum of bioactive effects in the human gastrointestinal (GI), which may include enzyme inhibition, inflammation and immune responses and of which much is not known. Similarly, although modifications during food processing (exposure to heat, moisture, salt, acid, fermentation) may affect their structure and activity as shown in vitro, it is important to relate these changes to effects that may present in the GI tract. Finally, much of our knowledge of their potential biological effects is based on studies in vitro and in animal models. Validation by human studies using processed foods as commonly consumed is warranted. We conclude that more detailed understanding of these factors may allow the effects of ATIs on human health to be better understood and when possible, to be ameliorated, for example by innovative food processing. We therefore review in short our current knowledge of these proteins, focusing on features which relate to their biological activity and identifying gaps in our knowledge and research priorities
Two randomized crossover multicenter studies investigating gastrointestinal symptoms after bread consumption in individuals with noncoeliac wheat sensitivity: do wheat species and fermentation type matter?
Background: Many individuals reduce their bread intake due to the belief that wheat is the cause of their gastrointestinal (GI) symptoms. Different grains and processing methods may impact tolerability.
Objective: We investigated the effects of six different types of bread on GI symptoms in individuals with self-reported non-coeliac wheat sensitivity (NCWS).
Methods: Two parallel randomised double-blind crossover multicentre studies were conducted. NCWS individuals, in whom coeliac disease and wheat allergy were ruled out, received five slices of (study A, n=20) yeast fermented (YF) or (study B, n=20) sourdough fermented (SF) bread made of bread wheat, spelt or emmer on three separate intervention days. Each test day was preceded by a run-in period of 3 days and separated by a wash-out period of at least 7 days. GI symptoms were evaluated by change in symptom score (test day minus average of the 3-day run-in period) on a 0-100mm visual analogue scale (delta VAS). Responders were defined as an increase in delta VAS of at least 15mm for overall GI symptoms, abdominal discomfort, abdominal pain, bloating and/or flatulence.
Results: The overall change in GI symptoms did not differ between breads of different grains (YF p=0.267; SF p=0.144). The number of responders was also comparable for both YF (6 to wheat, 5 to spelt, and 7 to emmer, p=0.761) and SF breads (9 to wheat, 7 to spelt, and 8 to emmer, p=0.761).
Conclusion: The majority of NCWS individuals experienced GI symptoms for at least one of the breads, but on a group level, no differences were found between different grain types for either YF or SF breads.
Clinical Trial Registry: ClinicalTrials.gov, NCT0408447
Comparative compositions of metabolites and dietary fibre components in doughs and breads produced from bread wheat, emmer and spelt and using yeast and sourdough processes.
Wholemeal flours from blends of bread wheat, emmer and spelt were processed into bread using yeast-based and sourdough fermentation. The bread wheat flour contained significantly higher concentrations of total dietary fibre and fructans than the spelt and emmer flours, the latter having the lowest contents. Breadmaking using sourdough and yeast systems resulted in changes in composition from flour to dough to bread including increases in organic acids and mannitol in the sourdough system and increases in amino acids and sugars (released by hydrolysis of proteins and starch, respectively) in both processing systems. The concentrations of fructans and raffinose (the major endogenous FODMAPs) were reduced by yeast and sourdough fermentation, with yeast having the greater effect. Both systems resulted in greater increases in sugars and glycerol in emmer than in bread wheat and spelt, but the significance of these differences for human health has not been established
Genomic patterns resembling BRCA1- and BRCA2-mutated breast cancers predict benefit of intensified carboplatin-based chemotherapy
Introduction: BRCA-mutated breast cancer cells lack the DNA-repair mechanism homologous recombination that is required for error-free DNA double-strand break (DSB) repair. Homologous recombination deficiency (HRD) may cause hypersensitivity to DNA DSB-inducing agents, such as bifunctional alkylating agents and platinum salts. HRD can be caused by BRCA mutations, and by other mechanisms. To identify HRD, studies have focused on triple-negative (TN) breast cancers as these resemble BRCA1-mutated breast cancer closely and might also share this hypersensitivity. However, ways to identify HRD in non-BRCA-mutated, estrogen receptor (ER)-positive breast cancers have remained elusive. The current study provides evidence that genomic patterns resembling BRCA1- or BRCA2- mutated breast cancers can identify breast cancer patients with TN as well as ER-positive, HER2-negative tumors that are sensitive to intensified, DSB-inducing chemotherapy. Methods: Array comparative genomic hybridization (aCGH) was used to classify breast cancers. Patients with tumors with similar aCGH patterns as BRCA1- and/or BRCA2-mutated breast cancers were defined as having a BRCA-like(CGH) status, others as non-BCRA-like(CGH). Stage-III patients (n = 249) had participated in a randomized controlled trial of adjuvant high-dose (HD) cyclophosphamide-thiotepa-carboplatin (CTC) versus 5-fluorouracil-epirubicin-cyclophosphamide (FE90C) chemotherapy. Results: Among patients with BRCA-like(CGH) tumors (81/249, 32%), a significant benefit of HD-CTC compared to FE90C was observed regarding overall survival (adjusted hazard ratio 0.19, 95% CI: 0.08 to 0.48) that was not seen for patients with non-BRCA-like(CGH) tumors (adjusted hazard ratio 0.90, 95% CI: 0.53 to 1.54) (P = 0.004). Half of all BRCA-like(CGH) tumors were ER-positive. Conclusions: Distinct aCGH patterns differentiated between HER2-negative patients with a markedly improved outcome after adjuvant treatment with an intensified DNA-DSB-inducing regimen (BRCA-like(CGH) patients) and those without benefit (non-BRCA-like(CGH) patients)
A combination of fecal calprotectin and human beta-defensin 2 facilitates diagnosis and monitoring of inflammatory bowel disease
Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) show a large overlap in clinical presentation, which presents diagnostic challenges. As a consequence, invasive and burdensome endoscopies are often used to distinguish between IBD and IBS. Here, we aimed to develop a noninvasive fecal test that can distinguish between IBD and IBS and reduce the number of endoscopies. We used shotgun metagenomic sequencing to analyze the composition and function of gut microbiota of 169 IBS patients, 447 IBD patients and 1044 population controls and measured fecal Calprotectin (FCal), human beta defensin 2 (HBD2), and chromogranin A (CgA) in these samples. These measurements were used to construct training sets (75% of data) for logistic regression and machine learning models to differentiate IBS from IBD and inactive from active IBD. The results were replicated on test sets (remaining 25% of the data) and microbiome data obtained using 16S sequencing. Fecal HBD2 showed high sensitivity and specificity for differentiating between IBD and IBS (sensitivity = 0.89, specificity = 0.76), while the inclusion of microbiome data with biomarkers (HBD2 and FCal) showed a potential for improvement in predictive power (optimal sensitivity = 0.87, specificity = 0.93). Shotgun sequencing-based models produced comparable results using 16S-sequencing data. HBD2 and FCal were found to have predictive power for IBD disease activity (AUC approximate to 0.7). HBD2 is a novel biomarker for IBD in patients with gastro-intestinal complaints, especially when used in combination with FCal and potentially in combination with gut microbiome data
Occurrence and temporal variations of TMDD in the river Rhine, Germany
Background, aim, and scope: The chemical substance 2,4,7,9-tetramethyl-5-decyne-4,7-diol (TMDD) is a non-ionic surfactant used as an industrial defoaming agent and in various other applications. Its commercial name is Surynol 104® and the related ethoxylates are also available as Surfynol® 420, 440, 465 and 485 which are characterized by different grades of ethoxylation of TMDD at both hydroxyl functional groups. TMDD and its ethoxylates offer several advantages in waterborne industrial applications in coatings, inks, adhesives as well as in paper industries. TMDD and its ethoxylates can be expected to reach the aquatic environment due its widespread use and its physico-chemical properties. TMDD has previously been detected in several rivers of Germany with concentrations up to 2.5 µg/L. In the United States, TMDD was also detected in drinking water. However, detailed studies about its presence and distribution in the aquatic environment have not been carried out so far. The aim of the present study was the analysis of the spatial and temporal concentration variations of TMDD in the river Rhine at the Rheingütestation Worms (443.3 km). Moreover, the transported load in the Rhine was investigated during two entire days and 7 weeks between November 2007 and January 2008.
Materials and methods: The sampling was carried out at three different sampling points across the river. Sampling point MWL1 is located in the left part of the river, MWL2 in the middle part, and MWL4 in the right part. One more sampling site (MWL3) was run by the monitoring station until the end of 2006, but was put out of service due to financial constrains. The water at the left side of the river Rhine (MWL1) is influenced by sewage from a big chemical plant in Ludwigshafen and by the sewage water from this city. The water at the right side of the river Rhine (MWL4) is largely composed of the water inflow from river Neckar, discharging into Rhine 14.9 km upstream from the sampling point and of communal and industrial wastewater from the city Mannheim. The water from the middle of the river (MWL2) is largely composed of water from the upper Rhine. Water samples were collected in 1-L bottles by an automatic sampler. The water samples were concentrated by use of solid-phase extraction (SPE) using Bond Elut PPL cartridges and quantified by use of gas chromatography-mass spectrometry (GC-MS). The quantification was carried out with the internal standard method. Based on these results, concentration variations were determined for the day profiles and week profiles. The total number of analyzed samples was 219.
Results: The results of this study provide information on the temporal concentration variability of TMDD in river Rhine in a cross section at one particular sampling point (443.3 km). TMDD was detected in all analyzed water samples at high concentrations. The mean concentrations during the 2 days were 314 ng/L in MWL1, 246 ng/L in MWL2, and 286 ng/L in MWL4. The variation of concentrations was low in the day profiles. In the week profiles, a trend of increasing TMDD concentrations was detected particularly in January 2008, when TMDD concentrations reached values up to 1,330 ng/L in MWL1. The mean TMDD concentrations during the week profiles were 540 ng/L in MWL1, 484 ng/L in MWL2, and 576 ng/L in MWL4. The loads of TMDD were also determined and revealed to be comparable in all three sections of the river. The chemical plant located at the left side of the Rhine is not contributing additional TMDD to the river. The load of TMDD has been determined to be 62.8 kg/d on average during the entire period. By extrapolation of data obtained from seven week profiles the annual load was calculated to 23 t/a.
Discussion: The permanent high TMDD concentrations during the investigation period indicate an almost constant discharge of TMDD into the river. This observation argues for effluents of municipal wastewater treatment plants as the most likely source of TMDD in the river. Another possible source might be the degradation of ethoxylates of TMDD (Surfynol® series 400), in the WWTPs under formation of TMDD followed by discharge into the river. TMDD has to be considered as a high-production-volume (HPV) chemical based on the high concentrations found in this study. In the United States, TMDD is already in the list of HPV chemicals from the Environmental Protection Agency (EPA). However, the amount of TMDD production in Europe is unknown so far and also the biodegradation rates of TMDD in WWTPs have not been investigated.
Conclusions: TMDD was found in high concentrations during the entire sampling period in the Rhine river at the three sampling points. During the sampling period, TMDD concentrations remained constant in each part of the river. These results show that TMDD is uniformly distributed in the water collected at three sampling points located across the river. ‘Waves’ of exceptionally high concentrations of TMDD could not be detected during the sampling period. These results indicate that the effluents of WWTPs have to be considered as the most important sources of TMDD in river Rhine.
Recommendations and perspectives: Based also on the occurrence of TMDD in different surface waters of Germany with concentrations up to 2,500 ng/L and its presence in drinking water in the USA, more detailed investigations regarding its sources and distribution in the aquatic environment are required. Moreover, the knowledge with respect to its ecotoxicity and its biodegradation pathway is scarce and has to be gained in more detail. Further research is necessary to investigate the rate of elimination of TMDD in municipal and industrial wastewater treatment plants in order to clarify the degradation rate of TMDD and to determine to which extent effluents of WWTPs contribute to the input of TMDD into surface waters. Supplementary studies are needed to clarify whether the ethoxylates of TMDD (known as Surfynol 400® series) are hydrolyzed in the aquatic environment resulting in formation of TMDD similar to the well known cleavage of nonylphenol ethoxylates into nonylphenols. The stability of TMDD under anaerobic conditions in groundwater is also unknown and should be studied
Gall-bladder dysmotility - A risk factor for gall-stone formation in hypertriglyceridaemia and reversal on triglyceride-lowering therapy with bezafibrate and fish oil
Doel: Onderzoeken van de pathofysiologische mechanismen die de kans op galstenen verhogen bij hypertriglyceridemie (HTG) en het vergelijken van de effecten van triglycerideverlagende therapie met bezafibraat en visolie op determinanten van cholelithiasis (biliaire lipidesamenstelling en galblaasmotoriek) bij HTG-patiënten.Opzet: Gekruiste opzet met ‘random’-volgorde.Patiënten en methoden: De galblaasmotoriek werd postprandiaal en tijdens cholecystokinine(CCK)-infusie echografisch onderzocht. De determinanten van cholelithiasis en de serumlipiden werden vergeleken tussen 9 HTG-patiënten en 10 normolipidemische controlepersonen van hetzelfde geslacht, dezelfde leeftijd en ‘body mass’-index. Bij de HTG-patiënten werden de effecten van bezafibraat en gezuiverde omega-3-olie (‘visolie’) bepaald.Resultaten: De serumtriglyceride(TG)-spiegel van de HTG-patiënten was 14-voudig verhoogd, vergeleken met de controlepersonen. De lipidesamenstelling van de gal, de nuchtere galblaasvolumen en de serum-CCK-spiegels verschilden niet tussen HTG-patiënten en controlepersonen. De galblaaslediging was verminderd bij HTG-patiënten versus controlepersonen tijdens CCK-infusie (–22) en ook na een maaltijd (–37; beide p < 0,001). De postprandiale serum-CCK-spiegels waren significant hoger bij HTG-patiënten. Zowel bezafibraat als visolie verlaagde de serum-TG-spiegel (–68 en –51 ten opzichte van de uitgangswaarde; beide: p < 0,01). Nuchtere CCK-spiegels verschilden niet, terwijl de CCK-geïnduceerde galblaaslediging onder bezafibraat toenam met 29 (p < 0,001) en met visolie met 13 (p = 0,07). De postprandiale galblaasmotoriek verbeterde tijdens zowel bezafibraat- (+47) als visoliebehandeling (+25; beide: p < 0,02), waarschijnlijk gedeeltelijk door een toegenomen gevoeligheid van de galblaas voor CCK (voor beide: p < 0,05 vergeleken met de uitgangsfase). Bezafibraat, in tegenstelling tot visolie, verhoogde de molaire cholesterol-galzuurratio (+40; p ≤ 0,05), terwijl beide behandelingen geen effect hadden op de cholesterolsaturatie-index.Conclusies: De verminderde galblaasmotoriek bij HTG-patiënten lijkt het gevolg te zijn van verminderde gevoeligheid voor CCK, wat kan bijdragen aan het verhoogde risico op galsteenvorming. Bij HTG-patiënten verbetert triglycerideverlagende therapie met visolie of bezafibraat de verminderde galblaasmotoriek zonder nadelig effect op de biliaire cholesterolverzadiging.Objective. To unravel the mechanisms responsible for the increased risk of gall-stone disease in hypertriglyceridaemia (HTG) and to compare the effects of triglyceride-lowering therapy with bezafibrate and fish oil on determinants of cholelithiasis (biliary-lipid composition and gall-bladder motility) in HTG patients. Design. Randomised cross over. Patients and methods. Gall-bladder motility (ultrasonography) was studied postprandially and during infusion of cholecystokinin (CCK). Determinants of cholelithiasis and serum lipids were compared between 9 HTG patients and 10 age, sex and body-mass index matched normolipidaemic controls. The effects of bezafibrate and purified omega-3-oil ('fish oil') in HTG patients were studied. Results. HTG patients showed 14-fold higher serum-triglyceride (TG) levels than controls. Biliary-lipid composition, fasting gall-bladder volumes, and CCK levels did not differ between HTG patients and controls. Gall-bladder emptying was reduced in HTG patients compared with controls during CCK infusion (-22%) as well as in response to a meal (-37%; both p < 0.001). Postprandial CCK levels were significantly higher in HTG patients. Both bezafibrate and fish oil reduced serum TG levels (-68 and -51% versus baseline, respectively; both p < 0.01). Fasting CCK levels were not affected whereas CCK-induced gall-bladder emptying increased during bezafibrate (+29%; p < 0.001) and tended to increase upon fish-oil therapy (+13%; p = 0.07). Postprandial gall-bladder motility improved at least partly with bezafibrate and fish oil (+47 and +25% versus baseline, respectively; both p < 0.02) due to increased gallbladder sensitivity to CCK (both p < 0.05 versus baseline). Bezafibrate but not fish oil increased the molar ratio of cholesterol to bile acids (+40%; p ≤ 0.05), but no effects on the cholesterol-saturation index were seen with either treatment. Conclusions. We suggest that impaired gall-bladder motility occurs in HTG patients due to decreased sensitivity to CCK, which may add to the enhanced risk of gall-stone disease in HTG patients. Triglyceride-lowering therapy by both fish oil and bezafibrate improves gall-bladder dysmotility without adversely affecting biliary-cholesterol saturation.</p
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