The acute effects of higher versus lower load duration and intensity on morphological and mechanical properties of the healthy Achilles tendon: a randomized crossover trial

ABSTRACT The Achilles tendon (AT) exhibits volume changes related to fluid flow under acute load which may be linked to changes in stiffness. Fluid flow provides a mechanical signal for cellular activity and may be one mechanism that facilitates tendon adaptation. This study aimed to investigate whether isometric intervention involving a high level of load duration and intensity could maximize the immediate reduction in AT volume and stiffness compared with interventions involving a lower level of load duration and intensity. Sixteen healthy participants (12 males, 4 females; age 24.4±9.4 years, body mass 70.9±16.1 kg, height 1.7±0.1 m) performed three isometric interventions of varying levels of load duration (2 s and 8 s) and intensity (35% and 75% maximal voluntary isometric contraction) over a 3 week period. Freehand 3D ultrasound was used to measure free AT volume (at rest) and length (at 35%, 55% and 75% of maximum plantarflexion force) pre- and post-interventions. The slope of the force–elongation curve over these force levels represented individual stiffness (N mm−1). Large reductions in free AT volume and stiffness resulted in response to long-duration high-intensity loading whilst less reduction was produced with a lower load intensity. In contrast, no change in free AT volume and a small increase in AT stiffness occurred with lower load duration. These findings suggest that the applied load on the AT must be heavy and sustained for a long duration to maximize immediate volume reduction, which might be an acute response that enables optimal long-term tendon adaptation via mechanotransduction pathways

Interlaboratory evaluation of an ELISA performed using a robotic automatic workstation versus manually testing for screening of Salmonella Typhimurium and Salmonella Choleraesuis antibodies in pig serum

An enzyme-linked immunosorbent assay (ELISA) was developed to detect antibodies directed against Salmonella spp. in porcine serum. This assay is based on the Exiqon VetScreen TM Salmonella Covalent Mix-ELISA 96-well microtiter plates (Jauho et al, 2000). These microtiter plates are photochemically coated with Salmonella typhimurium and Salmonella choleraesuis PS- antigens 1,4,5,6,7, and 12 using the ExiqonDs patented photochemical method for covalent coupling of ligands to polymer surfaces (Wiuff et al, 2000). The assay was developed using an automatic robotic workstation. The Exiqon VetScreen TM Salmonella Covalent Mix-ELISA plates do not require any blocking steps. The developed assay showed 30 minutes incubation time for porcine serum samples as optimal, thereby giving a total assay time of two hours. In order to evaluate the assay, a comparison study between the FSD, Canada; Exiqon, Copenhagen Denmark was performed. A panel of positive and negative porcine serum samples was tested. The tests were carried out using a robotic automatic workstation and using a manually performed assay in three different laboratories (Exiqon and Danish Veterinary Lab, Denmark; Svanova, Sweden).The developed assay showed high specificity, sensitivity and excellent reproducibility. The interlaboratory study gave results of substantial agreement. No difference between manual and robotized performance could be identified. The automated ELISA can be used in high throughput screening of swine Salmonella spp. antibodies in seroprevalence studies

Comparison of fatty acid profile and mineral content of black mulberry (Morus nigra), white mulberry (Morus alba) and red mulberry (Morus rubra) grown in Bahrain

This is the final version. Available on open access from Elsevier via the DOI in this recordAvailability of data and materials: Data available within the article or its supplementary materials.Mulberries are a rich source of many nutrients and have various health-promoting benefits. Nevertheless, their growth conditions can influence their nutritional composition and thus their benefits. Thus, this study examines the fatty acid profile and mineral content of three mulberry varieties: black (Morus nigra L.), white (Morus alba L.), and red (Morus rubra L.) grown in Bahrain for the first time. Fatty acid analysis, using gas chromatography-flame ionization detector (GC-FID), revealed that linoleic acid (C18:2n6) and palmitic acid (C16:0) were the primary fatty acids present in mulberry fruits, while minor fatty acids varied among the cultivars. Black mulberries exhibited a composition of 33.08 % saturated fatty acids (SFAs) and 66.92 % unsaturated fatty acids (UFAs), while red mulberries had 34.48 % SFAs and 66.52 % UFAs, and white mulberry had 27.15 % SFAs and 72.85 % UFAs. The mineral content analysis using inductively coupled plasma-optical emission spectroscopy (ICP-OES) revealed variations in the content of magnesium (Mg), iron (Fe), sodium (Na), potassium (K), and calcium (Ca) among the mulberry varieties. Black mulberries displayed the highest levels of Mg (706.67 mg/100 g), Fe (31.33 mg/100 g), Na (1406 mg/100 g), K (4161.33 mg/100 g), and Ca (1008.67 mg/100 g). Mulberries reported moderate levels of Mg (442.33 mg/100 g), Fe (45.6 mg/100 g), Na (635.68 mg/100 g), K (3278 mg/100 g), and Ca (583.1 mg/100 g). These findings indicate that black mulberries exhibit a superior mineral content across all parameters, whereas red mulberry has lower levels among the three varieties

SLC11A1 (NRAMP1) Polymorphisms and Tuberculosis Susceptibility: Updated Systematic Review and Meta-Analysis

Background: Natural resistance associated macrophage protein 1 (NRAMP1), encoded by the SLC11A1 gene, has been described to regulate macrophage activation and be associated with infectious and autoimmune diseases. The relation between SLC11A1 polymorphisms and tuberculosis susceptibility has been studied in different populations. Methods: We systematically reviewed published studies on SLC11A1 polymorphisms and tuberculosis susceptibility until September 15, 2010 and quantitatively summarized associations of the most widely studied polymorphisms using metaanalysis. Results: In total, 36 eligible articles were included in this review. In Meta-analysis, significant associations were observed between tuberculosis risk and widely studied SLC11A1 polymorphisms with summarized odds ratio of 1.35 (95%CI, 1.17– 1.54), 1.25 (95 % CI, 1.04–1.50), 1.23 (95 % CI, 1.04–1.44), 1.31 (95%CI, 1.08–1.59) for 39 UTR, D543N, INT4, and 59 (GT)n, respectively. Heterogeneity between studies was not pronounced, and the associations did not remarkably vary in the stratified analysis with respect to study population and study base. Conclusions: The association between SLC11A1 polymorphisms and tuberculosis susceptibility observed in our analyses supports the hypothesis that NRAMP1 might play an important role in the host defense to the development of tuberculosis

Using hand-held calculator to develop mathematical concepts of college freshman

For over a decade the graphic calculator has been promoted not only as a computational tool but also as a thinking tool. For example, as an aid to enhance conceptual understanding, as a problem solving tool and as means of enabling students to engage in meaningful investigations. However, research studies focusing on these aspects have shown mixed results and have mostly focused on graphs and functions. This research study was conducted to determine the effectiveness of handheld calculator to develop mathematical concepts of freshmen college. The subjects for this study were five college freshmen enrolled in College Algebra at Columban College -Sta. Cruz, Zarnbales. The use of graphics calculator design was used. The researcher himself handled the student within the period of seven weeks during the month of August and September. At the start of the semester, the students were expected to use the calculator features, this was suggested by the teacher simply demonstrating the use of particular feature and by the opportunity in these activities for students to freely use the calculator in investigations while the teacher acted as a consultant. Rubrics was used in the study to evaluate the performance in working with handheld calculator and journals. An activity sheet was given to the students after the discussions on the topics are through and journal has been evaluated. Their performance were classified as one of the following: novice, apprentice, practitioner and expert. At the end of the semester, the students are able to explore the problem situation using handheld calculator. They were able to explain the mathematical concepts effectively. Students gave a positive output showing better results from the given activity. They manifested the outcome as expected. The activities they performed using handheld calculator helped develop their understanding of concept. The multiple representations made possible by the calculator helped students comprehend situations graphically, numerically and symbolically. These visualizations allowed students to enjoy the subject and motivated them to learn

Reliability of human achilles tendon stiffness measures using freehand 3-D ultrasound

Achilles tendon (AT) stiffness is an important property of both human locomotor performance and injury mechanics. Freehand 3-D ultrasound (3-DUS) is a promising method for measuring stiffness of the Achilles tendon, particularly the free AT (2–6 cm proximal to calcaneus), which is commonly injured. The aim of this study was to investigate the test–retest reliability of freehand 3-DUS in measuring free AT stiffness in humans. The free Achilles tendon length of healthy participants (n = 10) was scanned on the same day on two consecutive occasions (1 h apart) during rest and isometric plantar flexion contractions at 20%, 40% and 60% of maximum force. The slope of the force–elongation curve over these force levels represented individual stiffness (N/mm). Relative reliability was assessed using the intra-class correlation coefficient (ICC), and absolute reliability was estimated with the standard error of measurement (SEM) and smallest detectable change. Systematic bias in stiffness measures was explored by comparing test and retest distributions and Bland–Altman plots. The test–retest reliability of free AT stiffness measured using freehand 3-DUS was excellent [ICC = 0.994, 95% confidence interval [CI]: 0.978–0.999)]. The mean stiffness values at test (361.83 N/mm [170.77]) and retest (364.98 N/mm [168.57]) did not significantly differ (p = 0.72), and the smallest detectable change was 52.14 N/mm. The Bland–Altman plot indicated the absence of systematic bias (95% CI: –22.18 to 15.88). Freehand 3-DUS provides reliable and precise measures of tendon stiffness and can be used to detect small changes in free AT stiffness in response to load or tendon pathology

Immediate and long-term effects of mechanical loading on Achilles tendon volume : a systematic review and meta-analysis

The Achilles tendon (AT) may experience changes in dimensions related to fluid flow under load. The extent to which fluid flow involves redistribution within or flow out of the tendon is not known and could be determined by investigating volume changes. This study aimed to synthesize data on immediate and long-term effects of loading on tendon volume among people with a healthy AT and midportion Achilles tendinopathy (MAT). A secondary aim was to synthesise data from the included studies investigating parallel change in cross-sectional area and length. Systematic electronic search was performed in MEDLINE, EMBASE, CINAHL, AMED, and Scopus from inception until May 2020. Standardized mean differences (SMDs) were calculated for intervention-induced changes from baseline for all outcomes. Methodological quality was assessed using modified version of Newcastle Ottawa Scale (NOS). Twelve studies were included in meta-analysis. For healthy AT, there were negligible to small changes in volume following cross-country running (-0.33 [95% CI=-1.11 to 0.45] (P=0.41)) and isometric exercise (0.01 [95% CI= -0.54 to 0.55] (P=0.98)) and a large increase at the short-term with 12-week isometric protocol (0.88 [95% CI= -0.10 to1.86] (P=0.08)). For MAT, there was an immediate large reduction in volume with isometric exercise (-1.24 [95% CI= -1.93 to -0.55] (P=0.0004)), small increase with eccentric exercise (0.41 [95% CI= -0.18 to 1.01](P=0.18)) and small reduction at the short-term with long-term interventions (-0.46 [95% CI= -0.87 to -0.05] (P=0.03)). This meta-analysis suggests that healthy AT remain isovolumetric with acute interventions while MAT exhibit immediate and short-term volume reductions in response to different interventions