ASSOCIATION BETWEEN T2* RELAXATION TIME AND THE MECHANICAL PARAMETERS OF THE ACHILLES TENDON IN TRAINED AND UNTRAINED POPULATIONS: PRELIMINARY DATA

The purpose of this study was twofold: 1) to investigate the association between T2* relaxation time and Achilles tendon mechanical/material parameters (e.g., stiffness, Young’s modulus and hysteresis); and 2) to check the sensibility of the T2* in determining the differences among population, providing important insight for sports scientist and clinicians. Thirty participants (10 power athletes, 10 endurance athletes and 10 healthy participants) participated in this study. Magnetic resonance imaging (MRI) was used to quantify T2* relaxation time at rest. Ultrasound, kinetics, EMG and kinematics data were used to calculate Achilles tendon mechanical/material parameters during maximum voluntary contractions of the plantar-flexor muscles. Preliminary data on power athletes and healthy controls suggest that the Achilles tendon Young’s was higher in power athletes compared with healthy control, whereas tendon hysteresis and T2* relaxation time were lower in power athletes. Tendon stiffness was similar between populations. Our preliminary data suggest that T2* can be utilised to investigate the differences between the population in terms of material parameters (Young’s modulus and hysteresis) but not in mechanical ones (e.g. stiffness)

Correlations between Achilles tendon material and structural properties and quantitative magnetic resonance imagining in different athletic populations

Achilles tendon stiffness (kAT) and Young's modulus (yAT) are important determinants of tendon function. However, their evaluation requires sophisticated equipment and time-consuming procedures. The goal of this study was twofold: to compare kAT and yAT between populations using the classical approach proposed in the literature (a combination of ultrasound and force data) and the MRI technique to understand the MRI's capability in determining differences in kAT and yAT. Furthermore, we investigated potential correlations between short and long T2* relaxation time, kAT and yAT to determine whether T2* relaxation time may be associated with material or structural properties. Twelve endurance and power athlete, and twelve healthy controls were recruited. AT T2* short and long components were measured using standard gradient echo MRI at rest, while kAT and yAT were evaluated using the classical method (combination of ultrasound and dynamometric measurements). Power athletes had the highest kAT (3064 ± 260, 2714 ± 260 and 2238 ± 189 N/mm for power athletes, endurance athletes and healthy control, respectively) and yAT (2.39 ± 0.28, 1.64 ± 0.22 and 1.97 ± 0.32 GPa for power athletes, endurance athletes and healthy control, respectively) and the lowest T2* short component (0.58 ± 0.07, 0.77 ± 0.06 and 0.74 ± 0.08 ms for power athletes, endurance athletes and healthy control, respectively). Endurance athletes had the highest T2* long component value. No correlations were reported between T2* long component, kAT or yAT in the investigated populations, whereas the T2* short component was negatively correlated with yAT. These results suggest that T2* short component could be used to investigate the differences in AT material properties in different populations

FOOTFALL PATTERN IS NOT ASSOCIATED WITH ALTERED ACHILLES TENDON T2* RELAXATION TIME OF RECREATIONAL DISTANCE RUNNERS

Achilles tendon (AT) tendinopathy was reported to be the pathology with one of the highest incidences of all running-related injuries. Non-rearfoot FP has been proposed to be the risk factor for AT overload. T2* relaxation time of Achilles tendon is considered to be a marker of AT tendinopathy. Therefore, the purpose of this study was to compare T2* relaxation time of Achilles tendon (AT) between recreational runner population with rearfoot (RF) and non-rearfoot (NR) footfall patterns (FP). Twenty-two middle age recreational runners (11 rearfoot and 11 non-rearfoot), matched according to running distance, participated in this study. Resting T2* relaxation time was determined using a 1.5 Tesla magnetic resonance imaging technique. Lower extremity kinematics and kinetics were recorded during over-ground running at a self-selected speed. No significant differences were found between T2* relaxation time of the insertion portion of the AT between RF and NR runners. Structural properties of the most injured part of the AT is not affected by running FP in healthy middle-aged runners

An 8.22 Mb Assembly and Annotation of the Alpaca (Vicugna pacos) Y Chromosome.

The unique evolutionary dynamics and complex structure make the Y chromosome the most diverse and least understood region in the mammalian genome, despite its undisputable role in sex determination, development, and male fertility. Here we present the first contig-level annotated draft assembly for the alpaca (Vicugna pacos) Y chromosome based on hybrid assembly of short- and long-read sequence data of flow-sorted Y. The latter was also used for cDNA selection providing Y-enriched testis transcriptome for annotation. The final assembly of 8.22 Mb comprised 4.5 Mb of male specific Y (MSY) and 3.7 Mb of the pseudoautosomal region. In MSY, we annotated 15 X-degenerate genes and two novel transcripts, but no transposed sequences. Two MSY genes, HSFY and RBMY, are multicopy. The pseudoautosomal boundary is located between SHROOM2 and HSFY. Comparative analysis shows that the small and cytogenetically distinct alpaca Y shares most of MSY sequences with the larger dromedary and Bactrian camel Y chromosomes. Most of alpaca X-degenerate genes are also shared with other mammalian MSYs, though WWC3Y is Y-specific only in alpaca/camels and the horse. The partial alpaca Y assembly is a starting point for further expansion and will have applications in the study of camelid populations and male biology

An 8.22 Mb Assembly and Annotation of the Alpaca (Vicugna pacos) Y Chromosome.

The unique evolutionary dynamics and complex structure make the Y chromosome the most diverse and least understood region in the mammalian genome, despite its undisputable role in sex determination, development, and male fertility. Here we present the first contig-level annotated draft assembly for the alpaca (Vicugna pacos) Y chromosome based on hybrid assembly of short- and long-read sequence data of flow-sorted Y. The latter was also used for cDNA selection providing Y-enriched testis transcriptome for annotation. The final assembly of 8.22 Mb comprised 4.5 Mb of male specific Y (MSY) and 3.7 Mb of the pseudoautosomal region. In MSY, we annotated 15 X-degenerate genes and two novel transcripts, but no transposed sequences. Two MSY genes, HSFY and RBMY, are multicopy. The pseudoautosomal boundary is located between SHROOM2 and HSFY. Comparative analysis shows that the small and cytogenetically distinct alpaca Y shares most of MSY sequences with the larger dromedary and Bactrian camel Y chromosomes. Most of alpaca X-degenerate genes are also shared with other mammalian MSYs, though WWC3Y is Y-specific only in alpaca/camels and the horse. The partial alpaca Y assembly is a starting point for further expansion and will have applications in the study of camelid populations and male biology

The International Workshop on Osteoarthritis Imaging Knee MRI Segmentation Challenge: A Multi-Institute Evaluation and Analysis Framework on a Standardized Dataset

Purpose: To organize a knee MRI segmentation challenge for characterizing the semantic and clinical efficacy of automatic segmentation methods relevant for monitoring osteoarthritis progression. Methods: A dataset partition consisting of 3D knee MRI from 88 subjects at two timepoints with ground-truth articular (femoral, tibial, patellar) cartilage and meniscus segmentations was standardized. Challenge submissions and a majority-vote ensemble were evaluated using Dice score, average symmetric surface distance, volumetric overlap error, and coefficient of variation on a hold-out test set. Similarities in network segmentations were evaluated using pairwise Dice correlations. Articular cartilage thickness was computed per-scan and longitudinally. Correlation between thickness error and segmentation metrics was measured using Pearson's coefficient. Two empirical upper bounds for ensemble performance were computed using combinations of model outputs that consolidated true positives and true negatives. Results: Six teams (T1-T6) submitted entries for the challenge. No significant differences were observed across all segmentation metrics for all tissues (p=1.0) among the four top-performing networks (T2, T3, T4, T6). Dice correlations between network pairs were high (>0.85). Per-scan thickness errors were negligible among T1-T4 (p=0.99) and longitudinal changes showed minimal bias (<0.03mm). Low correlations (<0.41) were observed between segmentation metrics and thickness error. The majority-vote ensemble was comparable to top performing networks (p=1.0). Empirical upper bound performances were similar for both combinations (p=1.0). Conclusion: Diverse networks learned to segment the knee similarly where high segmentation accuracy did not correlate to cartilage thickness accuracy. Voting ensembles did not outperform individual networks but may help regularize individual models.Comment: Submitted to Radiology: Artificial Intelligence; Fixed typo

Running and Physical Activity in an Air-Polluted Environment: The Biomechanical and Musculoskeletal Protocol for a Prospective Cohort Study 4HAIE (Healthy Aging in Industrial Environment—Program 4)

Far too little attention has been paid to health effects of air pollution and physical (in)activity on musculoskeletal health. The purpose of the Healthy aging in industrial environment study (4HAIE) is to investigate the potential impact of physical activity in highly polluted air on musculoskeletal health. A total of 1500 active runners and inactive controls aged 18–65 will be recruited. The sample will be recruited using quota sampling based on location (the most air-polluted region in EU and a control region), age, sex, and activity status. Participants will complete online questionnaires and undergo a two-day baseline laboratory assessment, including biomechanical, physiological, psychological testing, and magnetic resonance imaging. Throughout one-year, physical activity data will be collected through Fitbit monitors, along with data regarding the incidence of injuries, air pollution, psychological factors, and behavior collected through a custom developed mobile application. Herein, we introduce a biomechanical and musculoskeletal protocol to investigate musculoskeletal and neuro-mechanical health in this 4HAIE cohort, including a design for controlling for physiological and psychological injury factors. In the current ongoing project, we hypothesize that there will be interactions of environmental, biomechanical, physiological, and psychosocial variables and that these interactions will cause musculoskeletal diseases/protection

VITAMIN B12 DEFICIENCY IN CHILDREN – UNDERESTIMATED DANGER IN THE LIGHT OF NEW KNOWLEDGE

Vitamin B12 (kobalamin) ima dva aktivna oblika, adenozilkobalamin i metilkobalamin, koji imaju ključnu ulogu u dvama važnim metaboličkim putovima u ljudi i njihov je manjak odgovoran za kliničke teškoće u bolesnika. Kobalamin je nuždan tijekom cijelog života, no njegova dovoljna količina posebno je bitna u fetalno i dojenačko doba, kada je iznimno važan za normalan rast i razvoj djeteta, kao i za normalan razvoj središnjega živčanog sustava. Zbog vrlo složenog prometa i metabolizma njegov se manjak može očitovati pri raznim prirođenim i stečenim poremećajima. Klinička slika kojom se očituje manjak vitamina B12 obično je nespecifična, nosi velik rizik od trajnih posljedica za bolesnika, a najčešće se vrlo jednostavno liječi ako se na vrijeme prepozna. U Republici Hrvatskoj poremećaji metabolizma kobalamina u djece prerijetko se otkrivaju. Zato je cilj ovog rada skrenuti pozornost na nove spoznaje o metabolizmu kobalamina, prikazati bolesnike s tipičnim kliničkim tijekom i laboratorijskim nalazima te dati smjernice za brzo dijagnosticiranje i liječenje poremećaja vitamina B12 u djece.Vitamin B12 (cobalamin) has two active forms, adenosylcobalamin and methylcobalamin which have a key role in two important metabolic pathways in humans and their deficiency is responsible for clinical problems. Cobalamin is essential during whole life, but its sufficient amount is extra important in fetal and neonatal period, when it is essential for normal child growth and development as well as for normal development of the central nervous system. Because of very complex transport and metabolism, its deficiency can be manifested in numerous congenital and acquired disorders. Vitamin B12 deficiency mostly has non-specific clinical features, it carries a great risk of permanent consequences, but most frequently it is easily curable if diagnosed on time. In Croatia cobalamin deficiency in children has been diagnosed too rarely. Accordingly, the aim of this paper is to point to the recently gained knowledge on cobalamin metabolism, present typical case reports and to provide guidelines for rapid and proper diagnostic and therapeutic approach