Delineation of the mechanisms of tendon gliding resistance within the carpal tunnel

BACKGROUND: Forceful, high-velocity, and repetitive manual hand tasks contribute to the onset of carpal tunnel syndrome. This study aimed to isolate and identify mechanisms that contribute to tendon gliding resistance in the carpal tunnel. METHODS: Eight human cadaver hands (four pairs) were used. Tendon gliding resistance (force, energy, and stiffness) was measured under different conditions: with intact and with divided subsynovial connective tissue, at 2 mm/s and 60 mm/s tendon excursion velocity, and with and without relaxation time before tendon excursion. RESULTS: Subsynovial connective tissue stretching substantially contributed to increased gliding resistance force and energy during higher tendon excursion velocities, and subsynovial connective tissue stiffening was observed. Poroelastic properties of the tendon (and possibly the subsynovial connective tissue) also appear to be involved because relaxation time significantly increased gliding resistance force and energy (P<.01), and the difference in energy and force between high- and low-velocity tendon excursions increased with relaxation time (P=.01 and P<.01). Lastly, without relaxation time, no difference in force and energy was observed (P=.06 and P=.60), suggesting contact friction. INTERPRETATION: These findings are consistent with the hypothesis that the mechanics of tendon motion within the carpal tunnel are affected by the integrity of the subsynovial connective tissue. While not tested here, in carpal tunnel syndrome this tissue is known to be the fibrotic, thickened, and less-fluid-permeable. An extrapolation of our findings suggests that these changes in the subsynovial connective tissue of carpal tunnel syndrome patients could increase contact friction and carpal tunnel pressure

The Effect of Tendon Excursion Velocity on Longitudinal Median Nerve Displacement: Differences Between Carpal Tunnel Syndrome Patients and Controls

The subsynovial connective tissue (SSCT) is a viscoelastic structure connecting the median nerve (MN) and the flexor tendons in the carpal tunnel. Increased strain rates increases stiffness in viscoelastic tissues, and thereby its capacity to transfer shear load. Therefore, tendon excursion velocity may impact the MN displacement. In carpal tunnel syndrome (CTS) the SSCT is fibrotic and may be ruptured, and this may affect MN motion. In this study, ultrasonography was performed on 14 wrists of healthy controls and 25 wrists of CTS patients during controlled finger motions performed at three different velocities. Longitudinal MN and tendon excursion were assessed using a custom speckle tracking algorithm and compared across the three different velocities. CTS patients exhibited significantly less MN motion than controls (p ≤ 0.002). While in general, MN displacement increased with increasing tendon excursion velocity (p ≤ 0.031). These findings are consistent with current knowledge of SSCT mechanics in CTS, in which in some patients the fibrotic SSCT appears to have ruptured from the tendon surface

The emerging landscape of single-molecule protein sequencing technologies

Single-cell profiling methods have had a profound impact on the understanding of cellular heterogeneity. While genomes and transcriptomes can be explored at the single-cell level, single-cell profiling of proteomes is not yet established. Here we describe new single-molecule protein sequencing and identification technologies alongside innovations in mass spectrometry that will eventually enable broad sequence coverage in single-cell profiling. These technologies will in turn facilitate biological discovery and open new avenues for ultrasensitive disease diagnostics.Accepted Author ManuscriptChemE/Advanced Soft MatterBN/Chirlmin Joo LabBN/Cees Dekker La

Tree integration in homestead farms in southeast Nigeria: propositions and evidence.

This paper contributes to wider debates on the dominant factors determining the emergence and sustainability of intermediate systems of forest management in developing countries. The theoretical framework and propositions for analysing tree integration in homestead farms are presented, with reference to southeast Nigeria. The paper argues that, first, at the household level, livelihood strategies constitute the main determinant of the decision to integrate trees in homestead farms. Secondly, induced innovation has a wider and more significant role at the community level than at the household level in encouraging the integration of trees in farms. Thirdly, the sustainability of observed patterns of tree integration is influenced by the interaction of environmental, ecological, political, economic and social factors. Based on these propositions, the paper analyses the internal (household) and external (wider community) factors influencing tree integration in homestead farms in southeast Nigeria