K/B×N serum transfer arthritis is delayed and less severe in leukaemia inhibitory factor (LIF)-deficient mice

This study is investigating the role of leukaemia inhibitory factor (LIF) in the development of inflammation and joint damage in the mouse K/B×N serum transfer arthritis model. LIF knock-out (LIF(-/-)) mice were generated by mating heterozygote females (LIF(+/-)) with heterozygote males. Arthritis was induced in 8-20-week-old LIF knock-out mice (LIF(-/-)) by intraperitoneal injection of pooled K/B×N sera (50 µl) on days 0 and 2. Clinical disease was scored daily for 6 days. Safranin-O and haematoxylin-stained sections were scored for synovitis, joint space exudate, cartilage degradation and bone damage. RNA was extracted from ankle joints and used to investigate gene expression levels of tumour necrosis factor (TNF)-α, interleukin (IL)-1, LIF, LIF receptor, oncostatin M (OSM), OSM receptor, IL-6 and their common receptor subunit gp130 by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The results show that wild-type mice developed severe clinically overt polyarthritis. In contrast, LIF(-/-) mice showed a more than 50% reduction in clinical arthritis severity. Significantly lower histological scores were observed in LIF(-/-) mice compared to wild-type disease controls. LIF(-/-) mice had histopathological scores that were similar to normal healthy mice. IL-6 subfamily cytokine and receptor subunit expression remained unchanged. The expression levels for IL-6 were reduced significantly in all the diseased mice, whether wild-type or LIF(-/-) mice (P < 0·001), compared to healthy wild-type mice. We conclude that LIF contributes to the development of disease in the K/B×N serum transfer model of arthritis. These results provide further evidence for the role of LIF in inflammation and cartilage bone resorption and provide impetus to test the effects of LIF blockade as a therapeutic strategy in rheumatoid arthritis.

Strength of round and uterosacral ligaments: a biomechanical study

PURPOSE

To investigate the tensile biomechanical properties of round and uterosacral ligaments.

METHODS

Tissue samples were obtained from 15 female cadavers without pelvic organ prolapse. Uniaxial tensile tests were performed to obtain stiffness and maximum stress of round and uterosacral ligaments. Correlations were calculated using the Pearson correlation coefficient. Statistical differences between groups were tested using Student's paired and unpaired t test.

RESULTS

There was a great variability in the measurements of stiffness and maximum stress in pelvic ligaments. The round ligaments demonstrated stiffness of 9.1 ± 1.6 MPa (mean ± SEM) (ranging from 2 to 25.6 MPa) and maximum stress of 4.3 ± 0.7 MPa (ranging from 1.2 to 11.5 MPa). The stiffness of the uterosacral ligaments was 14.1 ± 1.4 MPa (ranging from 5.7 to 26.1 MPa) with maximum stress of 6.3 ± 0.8 MPa (ranging from 2.2 to 11.9 MPa). There was a strong positive correlation between stiffness and maximum stress in female pelvic ligaments (ρ = 0.851; p < 0.001). The uterosacral ligaments demonstrated higher stiffness and maximum stress compared to the round ligaments (p = 0.006 and p = 0.034; respectively). Age, body mass index and menopausal status were not associated with the biomechanical proprieties of round and uterosacral ligaments. Nulliparous women had lower uterosacral stiffness (15.5 ± 1.3 vs. 10 ± 1.8 MPa; p = 0.033) and maximum stress (8.2 ± 0.9 vs. 4.2 ± 1.1 MPa; p = 0.028) compared to parous women.

CONCLUSION

The uterosacral ligaments are significantly more resistant than round ligaments. Parturition seems to enhance the stiffness and maximum stress of the ligaments.

Physiological response of high-level female judokas measured through laboratory and field tests. Retesting the validity of the Santos test

AIM

The aim of the study was to measure the physiological demands of a group of high-level female judokas through laboratory tests and field tests (Tatami) and to retest the validity of the Santos test on a different population.

METHODS

Eight high-level female judokas participated in the study. Heart rate (HR), maximal oxygen consumption (VO2 max), blood lactate, anaerobic threshold, and ratings of perceived exertion (RPE) were measured using laboratory and field tests that shared common characteristics.

RESULTS

The mean (±SD) values obtained in the laboratory tests were HRmax 198.3 (4.1) beats.min-1, VO2 max: 40.9 (7.7) mL.kg-1.min-1, lactate max 9.1 (1.4) mmol.L-1, HR at the anaerobic threshold 171.5 (4.8) beats.min-1, lactate threshold 3.8 (0.4) mmol.L-1, and RPE: 17 (1.1). The mean (±SD) values obtained in the field test were HRmax 199.0 (5.0) beats.min-1, VO2 max: 44.8 (7.3) mL.kg-1.min-1, lactate max: 11.8 (1.5) mmol.l-1, HR at the anaerobic threshold 170.5 (3.2) beats.min-1, lactate threshold: 3.8 (0.1) mmol.L-1, and RPE: 18 (1.4) points. There were no significant differences between the data obtained on both tests in any of the parameters, except for the lactate maximum and VO2 max.

CONCLUSION

The Santos test is a helpful instrument for judo training in female athletes. Coaches could use it to design specific training protocols that could help to improve their performance in competition.

Electron-phonon coupling on the surface of the topological insulator Bi2Se3 determined from surface-phonon dispersion measurements

In this Letter, we report measurements of the coupling between Dirac fermion quasiparticles (DFQs) and phonons on the (001) surface of the strong topological insulator Bi2Se3. While most contemporary investigations of this coupling have involved examining the temperature dependence of the DFQ self-energy via angle-resolved photoemission spectroscopy measurements, we employ inelastic helium-atom scattering to explore, for the first time, this coupling from the phonon perspective. Using a Hilbert transform, we are able to obtain the imaginary part of the phonon self-energy associated with a dispersive surface-phonon branch identified in our previous work [Phys. Rev. Lett. 107, 186102 (2011)] as having strong interactions with the DFQs. From this imaginary part of the self-energy we obtain a branch-specific electron-phonon coupling constant of 0.43, which is stronger than the values reported from the angle-resolved photoemission spectroscopy measurements.

Distractor dinámico para el tratamiento de fracturas conminutas de las articulaciones interfalángicas proximales. Análisis biomecánico

Se analiza el comportamiento mecánico de un distractor dinámico para el tratamiento de las fracturas conminutas de las articulaciones interfalángicas proximales (IFP) de los dedos. El objetivo es establecer cuáles son los patrones de la tendencia a luxarse, y por lo tanto saber dónde y cómo colocar las agujas de Kirschner correctamente. Metodológicamente se aplica un sistema de modelización matemática del comportamiento mecánico del dedo índice de la mano, con vistas a evaluar la mejor forma de movilizar, total o parcialmente, la articulación IFP, y conseguir la restauración de la superficie articular. Los resultados tienen importantes aplicaciones clínicas: en las lesiones con inestabilidad volar, cuanto más cerca de la articulación IFP se coloque la aguja, menor será la tendencia a la inestabilidad; en las lesiones con inestabilidad dorsal, se deberá colocar la aguja lo más distalmente posible.

[Spinal arthrodesis. basic science]

Spinal arthrodesis consists of a combination of a system of mechanical stabilisation of one or more vertebral segments with a biological substance that promotes osteoneogenesis, with aim of achieving the permanent fusion between areas more or less the same size of these segments. In spinal arthrodesis, the biological support par excellence is the autograft. However, obtaining this involves a high incidence of morbidity and, in cases of arthrodesis of more than one intervertebral space, the quantity available is usually insufficient. The extraction and implantation time prolongs the surgery, increasing the exposure to and risk of bleeding and infection. For these reasons, there is a search for substances that possess the properties of the autograft, avoiding the morbidity and added surgical time required to extract the autograft. The biomechanical-biological interaction in vertebral arthrodesis has been studied in this article.

Interaction of phonons and dirac fermions on the surface of Bi2Se3: a strong Kohn anomaly

We report the first measurements of phonon dispersion curves on the (001) surface of the strong three-dimensional topological insulator Bi2Se3. The surface phonon measurements were carried out with the aid of coherent helium beam surface scattering techniques. The results reveal a prominent signature of the exotic metallic Dirac fermion quasiparticles, including a strong Kohn anomaly. The signature is manifest in a low energy isotropic convex dispersive surface phonon branch with a frequency maximum of 1.8 THz and having a V-shaped minimum at approximately 2kF that defines the Kohn anomaly. Theoretical analysis attributes this dispersive profile to the renormalization of the surface phonon excitations by the surface Dirac fermions. The contribution of the Dirac fermions to this renormalization is derived in terms of a Coulomb-type perturbation model.

Twin matter waves for interferometry beyond the classical limit

Interferometers with atomic ensembles are an integral part of modern precision metrology. However, these interferometers are fundamentally restricted by the shot noise limit, which can only be overcome by creating quantum entanglement among the atoms. We used spin dynamics in Bose-Einstein condensates to create large ensembles of up to 10(4) pair-correlated atoms with an interferometric sensitivity -1.61(-1.1)(+0.98) decibels beyond the shot noise limit. Our proof-of-principle results point the way toward a new generation of atom interferometers.