An investigation into the depth of penetration of low level laser therapy through the equine tendon in vivo

Low level laser therapy (LLLT) is frequently used in the treatment of wounds, soft tissue injury and in pain management. The exact penetration depth of LLLT in human tissue remains unspecified. Similar uncertainty regarding penetration depth arises in treating animals. This study was designed to test the hypothesis that transmission of LLLT in horses is increased by clipping the hair and/or by cleaning the area to be treated with alcohol, but is unaffected by coat colour. A LLLT probe (810 nm, 500 mW) was applied to the medial aspect of the superficial flexor tendon of seventeen equine forelimbs in vivo. A light sensor was applied to the lateral aspect, directly opposite the laser probe to measure the amount of light transmitted. Light transmission was not affected by individual horse, coat colour or leg. However, it was associated with leg condition (F = 4.42, p = 0.0032). Tendons clipped dry and clipped and cleaned with alcohol, were both associated with greater transmission of light than the unprepared state. Use of alcohol without clipping was not associated with an increase in light transmission. These results suggest that, when applying laser to a subcutaneous structure in the horse, the area should be clipped and cleaned beforehand

Mapping quantitative trait loci (QTL) in sheep. I. A new male framework linkage map and QTL for growth rate and body weight

A male sheep linkage map comprising 191 microsatellites was generated from a single family of 510 Awassi-Merino backcross progeny. Except for ovine chromosomes 1, 2, 10 and 17, all other chromosomes yielded a LOD score difference greater than 3.0 between the best and second-best map order. The map is on average 11% longer than the Sheep Linkage Map v4.7 male-specific map. This map was employed in quantitative trait loci (QTL) analyses on body-weight and growth-rate traits between birth and 98 weeks of age. A custom maximum likelihood program was developed to map QTL in half-sib families for non-inbred strains (QTL-MLE) and is freely available on request. The new analysis package offers the advantage of enabling QTL × fixed effect interactions to be included in the model. Fifty-four putative QTL were identified on nine chromosomes. Significant QTL with sex-specific effects (i.e. QTL × sex interaction) in the range of 0.4 to 0.7 SD were found on ovine chromosomes 1, 3, 6, 11, 21, 23, 24 and 26

Varying constants, Gravitation and Cosmology

Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. It is thus of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We thus detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, Solar system observations, meteorites dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.Comment: 145 pages, 10 figures, Review for Living Reviews in Relativit

Modulação da proliferação fibroblástica e da resposta inflamatória pela terapia a laser de baixa intensidade no processo de reparo tecidual Modulation of fibroblast proliferation and inflammatory response by low-intensity laser therapy in tissue repair process

FUNDAMENTOS: Ao longo dos anos, diversos estudos têm sido realizados para compreender o processo de reparo tecidual, bem como os possíveis efeitos da terapia a laser no processo de cicatrização de feridas. OBJETIVOS: Investigar o comportamento de feridas cutâneas provocadas na região dorsal de ratos Wistar (Rattus norvegicus), que foram submetidos ao tratamento com laser de baixa intensidade, com 3,8 J/cm² de dosagem, 15mW de potência e tempo de aplicação de 15s. MÉTODOS: Os animais (n = 12) foram divididos em dois grupos, um controle e outro tratado com laser. Foram realizadas, no grupo tratado, três aplicações (imediatamente após o ato cirúrgico, 48 horas e sete dias após a realização das feridas cirúrgicas). Dez dias após o ato cirúrgico foram colhidas amostras das lesões de ambos os grupos para realização de estudo histopatológico e histomorfométrico. RESULTADOS: Foram evidenciados aumentos da neovascularização e da proliferação fibroblástica, e diminuição da quantidade de infiltrado inflamatório nas lesões cirúrgicas submetidas à terapia com laser. CONCLUSÃO: Os resultados em conjunto sugerem que a terapia a laser de baixa intensidade é um método eficaz no processo de modulação da reparação tecidual, contribuindo significativamente para a cicatrização tecidual mais rápida e organizada.<br>BACKGROUND: Several studies have been performed to understand the tissue repair process as well as the possible effects of laser therapy in wound healing. OBJECTIVES: To study the behavior of skin wounds induced in the dorsal region of Wistar rats (Rattus norvegicus), which were submitted to the low-intensity laser therapy at 3.8 J/cm² dosage, 15mW potency, during 15 seconds. MATERIAL AND METHODS: The animals (n=12) were divided into two groups - control and laser-treated. The latter comprised three applications (immediately after surgery, 48 hours and 7 days after induction of surgical wounds). Ten days after surgery samples of the wounds were collected and submitted to histopathological and histomorphometric studies. RESULTS: Neovascularization, fibroblast proliferation and reduced inflammatory infiltrate in surgical wound submitted to laser therapy were demonstrated. CONCLUSION: Taken together, the results suggest that low-intensity laser therapy is an effective method to modulate tissue repair, thus significantly contributing to a faster and more organized healing process