Showing papers by "Mario Thevis published in 2018"
TL;DR: It is suggested that HU, through its effects on foetal hemoglobin and possibly on NO delivery, would modulate RBC NO signalling pathway, RBC rheology and oxidative stress.
34 citations
TL;DR: Assay validation demonstrated adequate sensitivity, precise and reproducible results for all included target insulins, and proof-of-principle data were obtained by the analysis of DBS samples obtained from healthy volunteers in non-fasting state as well as a sample from a diabetic volunteer treated with the fast acting analog insulin Aspart.
Abstract: While dried blood spot (DBS) analysis concerning low molecular mass molecules has become more and more established in various fields of analytical chemistry, the utility of DBS in determining peptides and proteins from DBS is yet comparably limited. In consideration of the fact that the apparent benefits of DBS sampling are similar for analytes of lower and higher molecular mass, dedicated (non-generic) sample preparation procedures are required that meet the needs for detecting peptidic drugs and hormones in DBS. The analysis of insulin and its synthetic analogs by mass spectrometry has received increased attention in several fields such as doping controls, forensics, and drug metabolism and pharmacokinetics studies. Hence, a strategy facilitating the analysis of insulin and its synthetic or animal analogs (human, Lispro, Aspart, Glulisine, Glargine, Detemir, Tresiba, and porcine and bovine insulin) from DBS was developed. The successful analysis of these substances at physiologically relevant concentrations was realized after ultrasonication-assisted extraction, immunoaffinity purification, and liquid chromatographic separation followed by high resolution mass spectrometric detection (with or without ion mobility). Assay validation demonstrated adequate sensitivity (LOD 0.5 ng/mL for most insulins), as well as precise (< 25%) and reproducible results for all included target insulins. Additionally, proof-of-principle data were obtained by the analysis of DBS samples obtained from healthy volunteers in non-fasting state as well as a sample from a diabetic volunteer treated with the fast acting analog insulin Aspart.
28 citations
TL;DR: The dissociation patterns of three new SARM drug candidates referred to as GSK2881078, PF-06260414, and TFM-4 AS-1 as observed under electron ionization as well as electrospray ionization/collision-induced dissociation are discussed.
Abstract: Selective androgen receptor modulators (SARMs) have been identified as a promising class of drug candidates potentially applicable to diverse pathological conditions commonly associated with signif...
21 citations
TL;DR: The combination of well-established strategies for the determination of peptides, such as two-dimensional liquid chromatography, dimethyl sulfoxide-assisted electrospray ionization, high resolution mass spectrometric detection and a tailored reporter template, provides a high-throughput initial testing assay for lower molecular mass peptidic and peptide-related analytes.
Abstract: In this work, a novel initial testing assay based on liquid chromatography-mass spectrometry is presented, enabling the detection of peptidic drugs and drug candidates (< 2 kDa) prohibited in sports. The assay covers representatives and metabolites of gonadotropin releasing hormone and its analogs (GnRHs), growth hormone secretagogues (GHS), growth hormone releasing peptides (GHRPs), and the Vasopressin-analog Desmopressin. The general objective of this work was to reduce sample preparation efforts to a minimum while preserving highest possible sensitivity and specificity of the assay, demonstrating limits of detection between 50 and 200 pg/mL. Here, a "dilute-and-inject" strategy provides the simplest conceivable sample preparation procedure. Furthermore, the combination of well-established strategies for the determination of peptides, such as two-dimensional liquid chromatography, dimethyl sulfoxide (DMSO)-assisted electrospray ionization, high resolution mass spectrometric detection and a tailored reporter template, which facilitates data review enormously, provides a high-throughput initial testing assay for lower molecular mass peptidic and peptide-related analytes.
19 citations
TL;DR: The structure of a long-term metabolite of dehydrochloromethyltestosterone (DHCMT) was elucidated and 8 possible metabolites with a 17α-methyl-17β-hydroxymethyl - structures were synthesized and compared to a major DHCMT long- term metabolite detected in reference urine excretion samples.
Abstract: In doping control analysis, the characterization of urinary steroid metabolites is of high interest for a targeted and long-term detection of prohibited anabolic androgenic steroids (AAS). In this work, the structure of a long-term metabolite of dehydrochloromethyltestosterone (DHCMT) was elucidated. Altogether, 8 possible metabolites with a 17α-methyl-17β-hydroxymethyl - structures were synthesized and compared to a major DHCMT long-term metabolite detected in reference urine excretion samples. The confirmed structure of the metabolite was 4α-chloro-18-nor-17β-hydroxymethyl-17α-methyl-5α-androst-13-en-3α-ol.
19 citations
TL;DR: The main human metabolite, dihydroxylated LGD-4033, was detected in the horse samples and was also produced by the fungus, however, it was not a major metabolite for horse and fungus, which highlights the importance of performing metabolism studies in the species of interest.
19 citations
TL;DR: Both preparation techniques were suitable for quantifying NPS in organ tissues and body fluids.
Abstract: An organ distribution investigation was carried out on two deceased (A and B) who consumed 4-methylethcathinone (4-MEC), methylenedioxypyrovalerone (MDPV), methoxetamine (MXE) and α-pyrrolidinopentiophenone (α-PVP). The detection of the aforementioned drugs in the specimens was performed on a liquid chromatography–tandem mass spectrometry system. Two different extraction methods were compared with each other—a quick, easy, cheap, effective, rugged and safe (QuEChERS) approach and an automated Instrument Top Sample Preparation-solid phase extraction (ITSP-SPE). Standard addition method was used to quantify the drugs. 4-MEC, MDPV and MXE were detected in all collected tissues and body fluids of the two deceased. α-PVP was also detectable in deceased A. Deceased A showed femoral blood concentrations of 97 µg/L 4-MEC, 396 µg/L MDPV, 295 µg/L MXE and 4 µg/L α-PVP measured after extraction by QuEChERS and 118 µg/L 4-MEC, 342 µg/L MDPV, 385 µg/L MXE and 4 µg/L α-PVP measured after ITSP-SPE. Deceased B revealed heart blood concentrations of 8 µg/L 4-MEC, 3 µg/L MDPV and 2 µg/L MXE after extraction by QuEChERS and 8 µg/L 4-MEC and 1 µg/L MXE after ITSP-SPE. Both preparation techniques were suitable for quantifying NPS in organ tissues and body fluids. With respect to the autopsy findings, the cause of death of deceased A was determined to be an acute intoxication with NPS. No certain cause of death could be ascertained for deceased B.
15 citations
TL;DR: The chemical structures of the two most promising glucuronidated metabolites were verified by in-house synthesis of both metabolites and confirmed by nuclear magnetic resonance analysis and both were successfully implemented into the currently applied analytical method for the detection of anabolic agents.
Abstract: A steroidal compound was recently detected in a seized black market product and was identified as (17α,20E)-17,20-[(1-methoxyethylidene) bis (oxy)]-3-oxo-19-norpregna-4,20-diene-21-carboxylic acid methyl ester (YK11). This compound is described to possess selective androgen receptor modulator- and myostatin inhibitor-like properties. As YK11 is an experimental drug candidate and a non-approved substance for humans, scientific data on its metabolism is scarce. Due to its steroidal backbone and the arguably labile orthoester-derived moiety positioned at the D-ring, substantial metabolic conversion in vivo was anticipated. To unambiguously detect urinary metabolites of YK11, an elimination study with six-fold deuterated YK11 was conducted. Post-administration specimens were analyzed using hydrogen isotope ratio mass spectrometry coupled to single quadrupole mass spectrometry to identify metabolites alongside basic mass spectrometric data. Further characterization of those metabolites relevant to sports drug testing was accomplished using gas chromatography-high resolution-high accuracy mass spectrometry. Fourteen deuterated urinary metabolites were detected comprising unconjugated, glucuronidated, and sulfoconjugated metabolites. As expected, no intact YK11 was observed in the elimination study urine samples. While the unconjugated metabolites disappeared within 24 hours post-administration, both glucuronidated and sulfated metabolites were traceable for more than 48 hours. The chemical structures of the two most promising glucuronidated metabolites (5β-19-nor-pregnane-3α,17β,20-triol and 5β-19-nor-pregnane-3α,17β-diol-20-one) were verified by in-house synthesis of both metabolites and confirmed by nuclear magnetic resonance analysis. In order to elucidate their potential in sports drug testing, both were successfully implemented into the currently applied analytical method for the detection of anabolic agents.
14 citations
TL;DR: These synthesized SARM-derived metabolites can readily be utilized as reference standards for routine mass spectrometry-based doping control analysis of at least three commonly used performance-enhancing drugs to unambigously identify misconduct.
Abstract: Selective androgen receptor modulators (SARMs) are a class of androgen receptor drugs, which have a high potential to be performance enhancers in human and animal sports. Arylpropionamides are one of the major SARM classes and get rapidly metabolized significantly complicating simple detection of misconduct in blood or urine sample analysis. Specific drug-derived metabolites are required as references due to a short half-life of the parent compound but are generally lacking. The difficulty in metabolism studies is the determination of the correct regio and stereoselectivity during metabolic conversion processes. In this study, we have elucidated and verified the chemical structure of two major equine arylpropionamide-based SARM metabolites using a combination of chemical synthesis and liquid chromatography-mass spectrometry (LC-MS) analysis. These synthesized SARM-derived metabolites can readily be utilized as reference standards for routine mass spectrometry-based doping control analysis of at least three commonly used performance-enhancing drugs to unambigously identify misconduct.
13 citations
TL;DR: Multidimensional gas chromatography was applied and the method was validated by determining the parameters linear range, limit of quantification, intra- and interday precision, accuracy and specificity utilizing linear mixing models and demonstrating that the method is suitable for an application in routine doping control analysis.
13 citations
TL;DR: The aim of this study was to develop a mass spectrometric detection assay for doping control serum samples using Bimagrumab, a human anti‐ActRII antibody found to increase muscle mass and function by blocking ActRII signaling.
Abstract: Purpose: Inhibitors of the ActRII signaling pathways represent promising therapeutics for the treatment of muscular diseases, but also pose risks as performance-enhancing agents in sports. Bimagrumab is a human anti-ActRII antibody which was found to increase muscle mass and function by blocking ActRII signaling. As it has considerable potential for being misused as doping agent in sports, the aim of this study was to develop a mass spectrometric detection assay for doping control serum samples. Experimental design: Within this study, a detection method for Bimagrumab in human serum was developed, which combines ammonium sulfate precipitation and affinity purification with proteolytic digestion and LC-HRMS. To facilitate the unambiguous identification of the diagnostic peptides, an orthogonal IM separation was additionally performed. Results: The assay was successfully validated and the analysis of clinical samples demonstrated its fitness for purpose for an application in routine doping control analysis. Conclusions and clinical relevance: Although no myostatin inhibitors have obtained clinical approval yet, the proactive development of detection methods for emerging doping agents represents a key aspect of preventive doping research. The presented approach will expand the range of available tests for novel protein therapeutics and can readily be modified to include further target analytes.
TL;DR: An assay for the combined detection of Sotatercept and Luspatercept in doping control serum samples was optimized, comprehensively characterized, and found to be fit-for-purpose for application to sports drug testing.
Abstract: Therapeutic proteins are a continuously growing class of pharmaceuticals and comprise several drug candidates with potential performance-enhancing properties. In particular, activin receptor competitors, such as the ActRII-Fc fusion proteins Sotatercept (ActRIIA-Fc) and Luspatercept (modified ActRIIB-Fc), have the potential for being misused as doping agents in sports as they were found to inhibit negative regulators of late-stage erythropoiesis. Within this study, ammonium sulfate precipitation, immunoaffinity purification, tryptic digestion, and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were employed to develop an assay for the combined detection of Sotatercept and Luspatercept in doping control serum samples. The assay was optimized, comprehensively characterized, and found to be fit-for-purpose for application to sports drug testing. It complements existing tests for ActRII-Fc fusion proteins and expands the range of available detection methods for novel protein therapeutics.
TL;DR: It was concluded from femoral blood analysis that the 27-year-old man found dead after falling from the 24th floor of a high-rise building was under the influence of the synthetic cannabinoid MDMB-CHMICA, THC, amphetamine and MDMA.
Abstract: This case report centres on the post-mortem distribution of the synthetic cannabinoid MDMB-CHMICA and its metabolites in the case of a 27-year-old man found dead after falling from the 24th floor of a high-rise building. Toxicological analysis of post-mortem samples confirmed, besides consumption of the synthetic cannabinoids MDMB-CHMICA (1.7 ng/mL femoral blood) and EG-018, the abuse of THC (9.3 ng/mL femoral blood), amphetamine (1050 ng/mL femoral blood), MDMA (275 ng/mL femoral blood), and cocaine. Regarding EG-018 and cocaine, only traces were detected in heart blood as well as in the brain (EG-018) and urine (cocaine), respectively, which is why no quantification was conducted in the femoral blood sample. It was concluded from femoral blood analysis that, at the time of death, the man was under the influence of the synthetic cannabinoid MDMB-CHMICA, THC, amphetamine and MDMA. Comprehensive screenings of all post-mortem specimens were conducted to elucidate the post-mortem distribution of MDMB-CHMICA and its metabolites. The MDMB-CHMICA concentrations ranged between 0.01 ng/mL (urine) and 5.5 ng/g (brain). Comparably low concentrations were detected in cardiac and femoral blood (2.1 ng/mL and 1.7 ng/mL, respectively) as well as in the psoas major muscle (1.2 ng/g). Higher concentrations were found in the lung (2.6 ng/g), liver (2.6 ng/g), and kidney (3.8 ng/g). Gastric content yielded a MDMB-CHMICA concentration of 2.4 ng/g (1.1 μg absolute). Screening for MDMB-CHMICA metabolites resulted in the detection of mainly monohydroxylated metabolites in the blood, kidney, and liver specimens. Results indicated that monohydroxylated metabolites of MDMB-CHMICA are appropriate target analytes for detecting MDMB-CHMICA intake.
TL;DR: An oral Co2+ dosage of 5 mg/day for 3 weeks effectively increases Hbmass with a tendency to increase hemoglobin concentration ([Hb]) and hematocrit (Hct).
Abstract: Introduction: Cobalt ions (Co2+) stabilize HIFα and increase endogenous erythropoietin (EPO) production creating the possibility that Co2+ supplements (CoSupp) may be used as performance enhancing substances The aim of this study was to determine the effects of a small oral dosage of CoSupp on hemoglobin mass (Hbmass) and performance with the objective of providing the basis for establishing upper threshold limits of urine [Co2+] to detect CoSupp misuse in sport Methods: Twenty-four male subjects participated in a double-blind placebo-controlled study Sixteen received an oral dose of 5 mg of ionized Co2+ per day for 3 weeks, and eight served as controls Blood and urine samples were taken before the study, during the study and up to 3 weeks after CoSupp Hbmass was determined by the CO-rebreathing method at regular time intervals, and VO2max was determined before and after the CoSupp administration period Results: In the Co2+ group, Hbmass increased by 20 ± 21% (p < 0001) while all the other analyzed hematological parameters did not show significant interactions of time and treatment Hemoglobin concentration ([Hb]) and hematocrit (Hct) tended to increase (p = 016, p = 01) and also [EPO] showed a similar trend (baseline: 95 ± 30, after 2 weeks: 124 ± 52 mU/ml) While mean VO2max did not change, there was a trend for a positive relationship between changes in Hbmass and changes in VO2max immediately after CoSupp (r = 040, p = 011) Urine [Co2+] increased from 04 ± 03 to 4714 ± 3841 ng/ml (p < 001) and remained significantly elevated until 2 weeks after cessation Conclusion: An oral Co2+ dosage of 5 mg/day for 3 weeks effectively increases Hbmass with a tendency to increase hemoglobin concentration ([Hb]) and hematocrit (Hct) Because urine Co2+ concentration remains increased for 2 weeks after cessation, upper limit threshold values for monitoring CoSupp can be established
TL;DR: To outline the variety of challenges that doping control laboratories are facing besides providing optimal detection capabilities and analytical comprehensiveness, selected case vignettes involving the follow-up of unconventional adverse analytical findings, urine sample manipulation, drug/food contamination issues, and unexpected biotransformation reactions are thematized.
Abstract: Analytical chemistry represents a central aspect of doping controls Routine sports drug testing approaches are primarily designed to address the question whether a prohibited substance is present in a doping control sample and whether prohibited methods (for example, blood transfusion or sample manipulation) have been conducted by an athlete As some athletes have availed themselves of the substantial breadth of research and development in the pharmaceutical arena, proactive and preventive measures are required such as the early implementation of new drug candidates and corresponding metabolites into routine doping control assays, even though these drug candidates are to date not approved for human use Beyond this, analytical data are also cornerstones of investigations into atypical or adverse analytical findings, where the overall picture provides ample reason for follow-up studies Such studies have been of most diverse nature, and tailored approaches have been required to probe hypotheses and scenarios reported by the involved parties concerning the plausibility and consistency of statements and (analytical) facts In order to outline the variety of challenges that doping control laboratories are facing besides providing optimal detection capabilities and analytical comprehensiveness, selected case vignettes involving the follow-up of unconventional adverse analytical findings, urine sample manipulation, drug/food contamination issues, and unexpected biotransformation reactions are thematized
TL;DR: Within this study, a slightly modified form of GH was discovered consisting of 192 amino acids carrying an additional alanine at the N-terminus, leading to a monoisotopic mass of 22,195 Da, confirmed by top-down and bottom-up experiments using liquid chromatography coupled to high resolution/high accuracy mass spectrometry.
Abstract: Detecting agents allegedly or evidently promoting growth such as human growth hormone (GH) or growth hormone releasing peptides (GHRP) in doping controls has represented a pressing issue for sports drug testing laboratories. While GH is a recombinant protein with a molecular weight of 22 kDa, the GHRPs are short (3–6 amino acids long) peptides with GH releasing properties. The endogenously produced GH (22 kDa isoform) consists of 191 amino acids and has a monoisotopic molecular mass of 22,124 Da. Within this study, a slightly modified form of GH was discovered consisting of 192 amino acids carrying an additional alanine at the N-terminus, leading to a monoisotopic mass of 22,195 Da. This was confirmed by top-down and bottom-up experiments using liquid chromatography coupled to high resolution/high accuracy mass spectrometry. Additionally, three analogues of GHRPs were identified as Gly-GHRP-6, Gly-GHRP-2 and Gly-Ipamorelin, representing the corresponding GHRP extended by a N-terminal glycine residue. The structure of these peptides was characterised by means of high resolution (tandem) mass spectrometry, and for Gly-Ipamorelin and Gly-GHRP-2 their identity was additionally confirmed by custom synthesis. Further, established in-vitro experiments provided preliminary information considering the potential metabolism after administration.
TL;DR: The SAR-PAGE method will be able to detect Sotatercept for several weeks and will be very useful in doping testing, and the adapted protocol for Luspatercept, another erythropoiesis stimulating fusion protein.
Abstract: A method for the detection of Sotatercept (ACE-011, ACVR2A-Fc) in human serum is presented. The method is a modification of a recently published protocol for Luspatercept (ACE-536, ACVR2B-Fc), another erythropoiesis stimulating fusion protein. Out of 27 tested antibodies against either the extracellular domain of ACVR2A or the full-length protein, only 4 antibodies bound strongly enough to Sotatercept for usage with immunoprecipitation followed by SAR-PAGE and Western single blotting. The adapted protocol allows the detection of 0.1 ng/mL Sotatercept in just 50 μL human serum. None of the 3 commercial ACVR2-ELISAs was able to detect Sotatercept and the 2 tested surrogate proteins, even in the μg/mL range. As for Luspatercept, only IPG-IEF/2D-PAGE generated discrete isoforms. Due to the long serum half-life, the SAR-PAGE method will be able to detect Sotatercept for several weeks and will be very useful in doping testing.
TL;DR: It is demonstrated that this capability can be used to reliably detect alterations as elicited by (putative) doping with 22 kDa-GH and opens an opportunity for independent confirmation, if combined with the antibody-based isoform differential test presently used in practice.
Abstract: Mass spectrometry (MS) allows for monitoring growth hormone (GH) isoform compositions at high specificity. It is demonstrated that this capability can be used to reliably detect alterations as elicited by (putative) doping with 22 kDa-GH. Sample treatment consists of enzymatic protein cleavage, followed by 2-step liquid chromatography clean-up, prior to analysis by MS. The protocol does not depend on antibodies for analyte extraction at any stage. Therefore, MS opens an opportunity for independent confirmation, if combined with the antibody-based isoform differential test presently used in practice. To check the fitness-for-purpose of this concept, GH-free serum was spiked with pure 22 kDa- and 20 kDa-GH covering a representative range of concentrations (0.5-9.4 μg/L), while the 22kDa fraction was within a range of 80%-85%, or at 100%, the latter simulating an administration of 22 kDa-GH. Mean deviation of 22 kDa-fractions found was within less than 3% for samples with total GH>= 1 μg/L . Beyond this, results by antibody-free isoform-differential MS, as described, were in line with those of the World Anti-Doping Agency-approved antibody-based test for 18 native sera and 3 positive controls. In this context, relating 22 kDa-GH to total-GH rather than 22 kDa+20 kDa was considered as an alternative strategy to earlier approaches. However, 20 kDa-GH as an additional measurand, next to 22 kDa- and total-GH, provides useful extra information, as it directly indicates the presence or absence of a non-22 kDa-GH form.
TL;DR: The updated protocols for the detection of Sotatercept and Luspatercept in human serum are faster, simpler, and cheaper and offer comparable sensitivities.
Abstract: We recently published two protocols for the detection of Sotatercept (ACE-011, ACVR2A-Fc) and Luspatercept (ACE-536, ACVR2B-Fc) in human serum. Both methods used covalently immobilized antibodies on agarose beads for immunoprecipitation and SAR-PAGE/Western blotting for detection. Disadvantages were the relatively high amount of antibody required per sample (10 μg) and the need of a secondary antibody for the final detection. The updated protocols overcome these limitations by antigen-antibody complex formation in solution followed by capture of the complex with anti-antibody-coated magnetic beads. They also omit the secondary antibody incubation step by usage of biotinylated primary antibodies, which can be directly incubated with streptavidin-HRP. Thus, the new protocols are faster, simpler, and cheaper and offer comparable sensitivities.
TL;DR: These results supported the interpretation of an atypical test result of a Central European athlete's doping control sample with δ13 C values for NorA of -18 ‰, most probably caused by the consumption of a wild boar ragout.
Abstract: Isotope ratio mass spectrometry (IRMS) has been established in doping control analysis to identify the endogenous or exogenous origin of a variety of steroidal analytes including the 19-norsteroid metabolite norandrosterone (NorA) NorA can be found naturally in human urine in trace amounts due to endogenous demethylation or in situ microbial degradation The administration of nortestosterone (nandrolone) or different prohormones results in the excretion of urinary NorA Usually, this can be detected by IRMS due to differing δ13 C values of synthetic 19-norsteroids compared to endogenous reference compounds The consumption of uncastrated pig edible parts like offal or even meat may also lead to a urinary excretion of NorA In order to determine the δ13 C values of such a scenario, urine samples collected after consumption of a wild-boar-testicle meal were analyzed IRMS revealed highly enriched δ13 C values for urinary NorA, which could be related to the completely corn-based nutrition of the animal Isotopic analysis of the boar's bristles demonstrated a dietary change from C3 -based forage, probably in winter and spring, to a C4 -based diet in the last weeks to months prior to death These results supported the interpretation of an atypical test result of a Central European athlete's doping control sample with δ13 C values for NorA of -18 ‰, most probably caused by the consumption of a wild boar ragout As stated before, athletes should be fully aware of the risk that consumption of wild boar may result in atypical or even adverse analytical findings in sports drug testing
TL;DR: In this model of oestrogen-dependent breast cancer in insulin-resistant rats, insulin and insulin analogues increased tumour multiplicity with no difference between insulin types.
Abstract: It is not fully clarified whether insulin glargine, an analogue with a high affinity for insulin-like growth factor-1 receptor (IGF-1R), increases the risk for cancers that abundantly express IGF-1R such as breast cancer or some types of breast cancer. To gain insight into this issue, female Sprague-Dawley rats fed a high-fat diet were given the carcinogen N-methyl-N-nitrosourea and randomly assigned to vehicle (control), NPH (unmodified human insulin), glargine or detemir (n = 30 per treatment). Insulins were given subcutaneously (15 U/kg/day) 5 days a week. Mammary tumours were counted twice weekly, and after 6 weeks of treatment, extracted for analysis. None of the insulin-treated groups had increased mammary tumour incidence at any time compared with control. At 6 weeks, tumour multiplicity was increased with NPH or glargine (P < 0.05) and tended to be increased with detemir (P = 0.2); however, there was no difference among insulins (number of tumours per rat: control = 0.8 ± 0.1, NPH = 1.8 ± 0.3, glargine = 1.5 ± 0.4, detemir = 1.4 ± 0.4; number of tumours per tumour-bearing rat: control = 1.3 ± 0.1, NPH = 2.2 ± 0.4, glargine = 2.7 ± 0.5, detemir = 2.3 ± 0.5). IGF-1R expression in tumours was lower than that in Michigan Cancer Foundation-7 (MCF-7) cells, a cell line that shows greater proliferation with glargine than unmodified insulin. In rats, glargine was rapidly metabolised to M1 that does not have greater affinity for IGF-1R. In conclusion, in this model of oestrogen-dependent breast cancer in insulin-resistant rats, insulin and insulin analogues increased tumour multiplicity with no difference between insulin types.
23 Apr 2018
TL;DR: It is concluded that exercise interventions of various intensities in the morning have no general effect on football-specific components of performance in the afternoon despite significant metabolic, endocrinological and cognitive short-term effects.
Abstract: The aim of this study was to investigate the effect of two different exercise interventions in the morning on football-specific components of performance in the afternoon under conditions simulating a competition day. In the morning on 3 experimental days, 12 football players (age 24.1 ± 5.5 years) completed three different preload interventions that were applied in a counter-balanced order: (1) no intervention (NI); (2) moderate-intensive exercise (MI); and (3) high-intensive exercise (HI). The subjects performed the preload exercises, consisting of a small-sided game and repeated maximal sprints, from 10:00–11:00 a.m. At 3:00 p.m., the Bangsbo test (BT) was applied to examine the effects of the different morning interventions on football-specific endurance capacity. The results showed that the HI led to significantly higher blood-lactate concentrations (moderate to very large effect) and heart rates (very large to extremely large effect) compared to the MI. In addition, there was a significant measurement × intervention effect on concentrations of adrenalin and noradrenalin in the urine, which reached higher values immediately after the HI (very large effect) and MI (moderate effect) compared to NI. All effects disappeared by the time of the BT in the afternoon. During all trials, after the preload intervention, reaction time and critical flicker fusion frequency increased significantly compared to the baseline morning values (reaction time: small; critical flicker fusion: trivial to small effect), but no measurement × intervention interaction was found. During the BT, the mean total distance covered (trivial to small effect) and the pacing pattern did not differ significantly among the trials despite numerous small individual effects. We conclude that exercise interventions of various intensities in the morning have no general effect on football-specific components of performance in the afternoon despite significant metabolic, endocrinological and cognitive short-term effects. Coaches should consider individual preferences when prescribing competition-day procedures.