Baboon (Papio ursinus) single fibre contractile properties are similar to that of trained humans.

This study investigated the contractile properties of single skeletal muscle fibres from the Vastus lateralis (VL) of two male adult chachma baboons (Papio ursinus) and compared it to that from five male human cyclists. Species comparisons are observational and statistical analyses were not performed due to the low sample size. The histological analyses revealed that the baboon muscles contained more type II fibres than their human counterparts. Cross-sectional areas of type I and type II fibres from human VL were similar in size, whereas baboon type I and type II fibres appeared smaller and larger compared to humans, respectively. On average, type II fibres from baboons and type IIAX fibres from humans produced the highest specific force (88 ± 41 and 155 ± 4 kN/m2, respectively), compared to 57 ± 27 and 68 ± 5 kN/m2 for baboon and human type I fibres. Maximum shortening velocity appeared highest in human type IIAX fibres, but fairly similar between human and baboon type I and II fibres. Baboon and human type I (2.2 ± 0.4 vs. 1.5 ± 0.5 kN/m2 Fl/s) and type II (6.0 ± 2.8 vs. 7.7 ± 1.0 kN/m2 Fl/s) fibres appeared similar in maximum power output. From these observations, it seems that baboon and human muscle fibre contractile properties appear similar to one another, and that fibre type composition itself may play a determining role in muscle strength between these two species.

Carpal tunnel syndrome: The role of collagen gene variants.

INTRODUCTION: The direct causes of idiopathic carpal tunnel syndrome (CTS) are still unknown. It is suggested that pathology of the tendons and other connective tissue structures within the carpal tunnel may play a role in its aetiology. Variants in genes encoding connective tissue proteins, such as type V collagen, have previously been associated with CTS. Since variants within other collagen genes, such as type I, XI and XII collagen, have previously been associated with modulating the risk of musculoskeletal soft tissue injuries, the aim of this study was to determine whether variants within COL1A1, COL11A1, COL11A2 and COL12A1 were associated with CTS. METHODS: Self-reported Coloured South African participants, with a history of carpal tunnel release surgery (CTS, n=103) and matched control (CON, n=150) participants without any reported history of CTS symptoms were genotyped for COL1A1 rs1800012 (G/T), COL11A1 rs3753841 (T/C), COL11A1 rs1676486 (C/T), COL11A2 rs1799907 (T/A) and COL12A1 rs970547 (A/G). RESULTS: The TT genotype of COL11A1 rs3753841 was significantly over-represented in the CTS group (21.4%) compared to CON group (7.9%, p=0.004). Furthermore, a trend for the T minor allele to be over-represented in the CTS group (p=0.055) with a significant association when only female participants (p=0.036) were investigated was observed. Constructed inferred pseudo-haplotypes including a previously investigated COL5A1 variant, rs71746744 (-/AGGG), suggest gene-gene interactions between COL5A1 and COL11A1 modulate the risk of CTS. DISCUSSION: These findings provide further information of the role of the genetic risk factors and the possible role of variations in collagen fibril composition in the aetiology of CTS. Genetic factors could potential be included in models developed to identify indivisuals at risk of CTS. Strategies that target modifiable risk factors to mitigate the effect of non-modifiable risk factors, such as the genetic risk, could be also developed to reduce incidence and morbidity of CTS.