22 research outputs found

    Sprint cycling rate of torque development associates with strength measurement in trained cyclists

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    Purpose: A cyclist’s rate of force/torque development (RFD/RTD) and peak force/torque can be measured during single-joint or whole-body isometric tests, or during cycling. However, there is limited understanding of the relationship between these measures, and of the mechanisms that contribute to each measure. Therefore, we examined the: (i) relationship between quadriceps central and peripheral neuromuscular function with RFD/RTD in isometric knee extension, isometric mid-thigh pull (IMTP), and sprint cycling; and (ii) relationship among RFD/RTD and peak force/torque between protocols. Methods: Eighteen trained cyclists completed two familiarisation and two experimental sessions. Each session involved an isometric knee extension, IMTP, and sprint cycling protocol, where peak force/torque, average and peak RFD/RTD, and early (0 – 100 ms) and late (0–200 ms) RFD/RTD were measured. Additionally, measures of quadriceps central and peripheral neuromuscular function were assessed during the knee extension. Results: Strong relationships were observed between quadriceps early EMG activity (EMG50/M) and knee extension RTD (r or ρ = 0.51 – 0.65) and IMTP late RFD (r = 0.51), and between cycling early or late RTD and peak twitch torque (r or ρ = 0.70 – 0.75). Strong-to-very strong relationships were observed between knee extension, IMTP, and sprint cycling for peak force/torque, early and late RFD/RTD, and peak RFD/RTD (r or ρ = 0.59 – 0.80). Conclusion: In trained cyclists, knee extension RTD or IMTP late RFD are related to measures of quadriceps central neuromuscular function, while cycling RTD is related to measures of quadriceps peripheral neuromuscular function. Further, the strong associations among force/torque measures between tasks indicate a level of transferability across tasks

    Imaging in gynecological disease (17): ultrasound features of malignant ovarian yolk sac tumors (endodermal sinus tumors)

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    Objective To describe the clinical and sonographic characteristics of malignant ovarian yolk sac tumors (YSTs). Methods In this retrospective multicenter study, we included 21 patients with a histological diagnosis of ovarian YST and available transvaginal ultrasound images and/or videoclips and/or a detailed ultrasound report. Ten patients identified from the International Results All cases were pure YSTs, except for one that was a mixed tumor (80% YST and 20% embryonal carcinoma). Median age at diagnosis was 25 (interquartile range (IQR), 19.5–30.5) years. Seventy-six percent (16/21) of women had an International Federation of Gynecology and Obstetrics (FIGO) Stage I–II tumor at diagnosis. Fifty-eight percent (11/19) of women felt pain during the ultrasound examination and one presented with ovarian torsion. Median serum α-fetoprotein (S-AFP) level was 4755 (IQR, 1071–25 303) ÎŒg/L and median serum CA 125 level was 126 (IQR, 35–227) kU/L. On ultrasound assessment, 95% (20/21) of tumors were unilateral. The median maximum tumor diameter was 157 (IQR, 107–181) mm and the largest solid component was 110 (IQR, 66–159) mm. Tumors were classified as either multilocular-solid (10/21; 48%) or solid (11/21; 52%). Papillary projections were found in 10% (2/21) of cases. Most (20/21; 95%) tumors were well vascularized (color score, 3–4) and none had acoustic shadowing. Malignancy was suspected in all cases, except in the patient with ovarian torsion, who presented a tumor with a color score of 1, which was classified as probably benign. Image and videoclip quality was considered as adequate in 18/21 cases. On review of the images and videoclips, we found that all tumors contained both solid components and cystic spaces, and that 89% (16/18) had irregular, still fine-textured and slightly hyperechoic solid tissue, giving them a characteristic appearance. Conclusion Malignant ovarian YSTs are often detected at an early stage, in young women usually in the second or third decade of life, presenting with pain and markedly elevated S-AFP. On ultrasound, malignant ovarian YSTs are mostly unilateral, large and multilocular-solid or solid, with fine-textured slightly hyperechoic solid tissue and rich vascularization. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology

    31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

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    Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

    Energy Expenditure Equation Choice: Effects on Cycling Efficiency and its Reliability

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    Purpose: There are several published equations to calculate energy expenditure (EE) from gas exchanges. The authors assessed whether using different EE equations would affect gross efficiency (GE) estimates and their reliability. Methods: Eleven male and 3 female cyclists (age 33 [10] y; height: 178 [11] cm; body mass: 76.0 [15.1] kg; maximal oxygen uptake: 51.4 [5.1] mL·kg−1·min−1; peak power output: 4.69 [0.45] W·kg−1) completed 5 visits to the laboratory on separate occasions. In the first visit, participants completed a maximal ramp test to characterize their physiological profile. In visits 2 to 5, participants performed 4 identical submaximal exercise trials to assess GE and its reliability. Each trial included three 7-minute bouts at 60%, 70%, and 80% of the gas exchange threshold. EE was calculated with 4 equations by PĂ©ronnet and Massicotte, Lusk, Brouwer, and Garby and Astrup. Results: All 4 EE equations produced GE estimates that differed from each other (all P < .001). Reliability parameters were only affected when the typical error was expressed in absolute GE units, suggesting a negligible effect—related to the magnitude of GE produced by each EE equation. The mean coefficient of variation for GE across different exercise intensities and calculation methods was 4.2%. Conclusions: Although changing the EE equation does not affect GE reliability, exercise scientists and coaches should be aware that different EE equations produce different GE estimates. Researchers are advised to share their raw data to allow for GE recalculation, enabling comparison between previous and future studies

    Targeted vaccination against the bevacizumab binding site on VEGF using 3D-structured peptides elicits efficient antitumor activity

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    Therapeutic targeting of the VEGF signaling axis by the VEGFneutralizing monoclonal antibody bevacizumab has clearly demonstrated clinical benefit in cancer patients. To improve this strategy using a polyclonal approach, we developed a vaccine targeting VEGF using 3D-structured peptides that mimic the bevacizumab binding site. An in-depth study on peptide optimization showed that the antigen's 3D structure is essential to achieve neutralizing antibody responses. Peptide 1 adopts a clear secondary, native-like structure, including the typical cysteine-knot fold, as evidenced by CD spectroscopy. Binding and competition studies with bevacizumab in ELISA and surface plasmon resonance analysis revealed that peptide 1 represents the complete bevacizumab binding site, including the hairpin loop (ÎČ5-turn-ÎČ6) and the structure-supporting ÎČ2-α2-ÎČ3 loop. Vaccination with peptide 1 elicited high titers of cross-reactive antibodies to VEGF, with potent neutralizing activity. Moreover, vaccination-induced antisera displayed strong angiostatic and tumor-growth-inhibiting properties in a preclinical mouse model for colorectal carcinoma, whereas antibodies raised with peptides exclusively encompassing the ÎČ5-turn-ÎČ6 loop (peptides 15 and 20) did not. Immunization with peptide 1 or 7 (murine analog of 1) in combinationwith the potent adjuvant raffinose fatty acid sulfate ester (RFASE) showed significant inhibition of tumor growth in the B16F10 murine melanoma model. Based on these data, we conclude that this vaccination technology,which is currently being investigated in a phase I clinical trial (NCT02237638), can potentially outperform currently applied anti-VEGF therapeutics.</p

    Exploration of the Design Principles of a Cell-Penetrating Bicylic Peptide Scaffold

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    Cell-penetrating peptides (CPPs) possess the capacity to induce cell entry of themselves and attached molecular cargo, either by endocytosis or by direct translocation. Conformational constraints have been described as one means to increase the activity of CPPs, especially for direct crossing of the plasma membrane. Here, we explored the structure–activity relationship of bicyclic peptides for cell entry. These peptides may be considered minimal analogues of naturally occurring oligocyclic peptide toxins and are a promising scaffold for the design of bioactive molecules. Increasing numbers of arginine residues that are primarily contributing to cell-penetrating activity were introduced either into the cycles, or as stretches outside the cycles, at both ends or at one end only. In addition, we probed for the impact of negatively charged residues on activity for both patterns of arginine substitution. Uptake was investigated in HeLa cells by flow cytometry and confocal microscopy. Overall, uptake efficiency showed a positive correlation with the number of arginine residues. The subcellular distribution was indicative of endocytic uptake. One linear stretch of arginines coupled outside the bicycle was as effective in promoting uptake as substituting the same number of arginines inside the bicycles. However, the internally substituted analogues were more sensitive to the presence of negatively charged residues. For a given bicyclic peptide, uptake was more effective than for the linear counterpart. Introduction of histidine and tryptophans further increased uptake efficiency to comparable levels as that of nonaarginine despite the larger size of the bicyclic backbone. The results demonstrate that both arginine clustering and spatial constraints are uptake-promoting structural principles, an observation that gives freedom in the introduction of cell-penetrating capacity to structurally constrained scaffolds

    Imaging in gynecological disease (17): ultrasound features of malignant ovarian yolk sac tumors (endodermal sinus tumors)

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    Objective To describe the clinical and sonographic characteristics of malignant ovarian yolk sac tumors (YSTs). Methods In this retrospective multicenter study, we included 21 patients with a histological diagnosis of ovarian YST and available transvaginal ultrasound images and/or videoclips and/or a detailed ultrasound report. Ten patients identified from the International Results All cases were pure YSTs, except for one that was a mixed tumor (80% YST and 20% embryonal carcinoma). Median age at diagnosis was 25 (interquartile range (IQR), 19.5–30.5) years. Seventy-six percent (16/21) of women had an International Federation of Gynecology and Obstetrics (FIGO) Stage I–II tumor at diagnosis. Fifty-eight percent (11/19) of women felt pain during the ultrasound examination and one presented with ovarian torsion. Median serum α-fetoprotein (S-AFP) level was 4755 (IQR, 1071–25 303) ÎŒg/L and median serum CA 125 level was 126 (IQR, 35–227) kU/L. On ultrasound assessment, 95% (20/21) of tumors were unilateral. The median maximum tumor diameter was 157 (IQR, 107–181) mm and the largest solid component was 110 (IQR, 66–159) mm. Tumors were classified as either multilocular-solid (10/21; 48%) or solid (11/21; 52%). Papillary projections were found in 10% (2/21) of cases. Most (20/21; 95%) tumors were well vascularized (color score, 3–4) and none had acoustic shadowing. Malignancy was suspected in all cases, except in the patient with ovarian torsion, who presented a tumor with a color score of 1, which was classified as probably benign. Image and videoclip quality was considered as adequate in 18/21 cases. On review of the images and videoclips, we found that all tumors contained both solid components and cystic spaces, and that 89% (16/18) had irregular, still fine-textured and slightly hyperechoic solid tissue, giving them a characteristic appearance. Conclusion Malignant ovarian YSTs are often detected at an early stage, in young women usually in the second or third decade of life, presenting with pain and markedly elevated S-AFP. On ultrasound, malignant ovarian YSTs are mostly unilateral, large and multilocular-solid or solid, with fine-textured slightly hyperechoic solid tissue and rich vascularization. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology

    External Validation of the Ovarian-Adnexal Reporting and Data System (O-RADS) Lexicon and the International Ovarian Tumor Analysis 2-Step Strategy to Stratify Ovarian Tumors Into O-RADS Risk Groups

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    IMPORTANCE: Correct diagnosis of ovarian cancer results in better prognosis. Adnexal lesions can be stratified into the Ovarian-Adnexal Reporting and Data System (O-RADS) risk of malignancy categories with either the O-RADS lexicon, proposed by the American College of Radiology, or the International Ovarian Tumor Analysis (IOTA) 2-step strategy.OBJECTIVE: To investigate the diagnostic performance of the O-RADS lexicon and the IOTA 2-step strategy.DESIGN, SETTING, AND PARTICIPANTS: Retrospective external diagnostic validation study based on interim data of IOTA5, a prospective international multicenter cohort study, in 36 oncology referral centers or other types of centers. A total of 8519 consecutive adult patients presenting with an adnexal mass between January 1, 2012, and March 1, 2015, and treated either with surgery or conservatively were included in this diagnostic study. Twenty-five patients were excluded for withdrawal of consent, 2777 were excluded from 19 centers that did not meet predefined data quality criteria, and 812 were excluded because they were already in follow-up at recruitment. The analysis included 4905 patients with a newly detected adnexal mass in 17 centers that met predefined data quality criteria. Data were analyzed from January 31 to March 1, 2022.EXPOSURES: Stratification into O-RADS categories (malignancy risk <1%, 1% to <10%, 10% to <50%, and ≄50%). For the IOTA 2-step strategy, the stratification is based on the individual risk of malignancy calculated with the IOTA 2-step strategy.MAIN OUTCOMES AND MEASURES: Observed prevalence of malignancy in each O-RADS risk category, as well as sensitivity and specificity. The reference standard was the status of the tumor at inclusion, determined by histology or clinical and ultrasonographic follow-up for 1 year. Multiple imputation was used for uncertain outcomes owing to inconclusive follow-up information.RESULTS: Median age of the 4905 patients was 48 years (IQR, 36-62 years). Data on race and ethnicity were not collected. A total of 3441 tumors (70%) were benign, 978 (20%) were malignant, and 486 (10%) had uncertain classification. Using the O-RADS lexicon resulted in 1.1% (24 of 2196) observed prevalence of malignancy in O-RADS 2, 4% (34 of 857) in O-RADS 3, 27% (246 of 904) in O-RADS 4, and 78% (732 of 939) in O-RADS 5; the corresponding results for the IOTA 2-step strategy were 0.9% (18 of 1984), 4% (58 of 1304), 30% (206 of 690), and 82% (756 of 927). At the 10% risk threshold (O-RADS 4-5), the O-RADS lexicon had 92% sensitivity (95% CI, 87%-96%) and 80% specificity (95% CI, 74%-85%), and the IOTA 2-step strategy had 91% sensitivity (95% CI, 84%-95%) and 85% specificity (95% CI, 80%-88%).CONCLUSIONS AND RELEVANCE: The findings of this external diagnostic validation study suggest that both the O-RADS lexicon and the IOTA 2-step strategy can be used to stratify patients into risk groups. However, the observed malignancy rate in O-RADS 2 was not clearly below 1%
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