Myostatin gene promoter: structure, conservation and importance as a target for muscle modulation.

Myostatin (MSTN) is one of the key factors regulating myogenesis. Because of its role as a negative regulator of muscle mass deposition, much interest has been given to its protein and, in recent years, several studies have analysed MSTN gene regulation. This review discusses the MSTN gene promoter, focusing on its structure in several animal species, both vertebrate and invertebrate. We report the important binding sites considering their degree of phylogenetic conservation and roles they play in the promoter activity. Finally, we discuss recent studies focusing on MSTN gene regulation via promoter manipulation and the potential applications they have both in medicine and agriculture.

CREB, NF-Y and MEIS1 conserved binding sites are essential to balance Myostatin promoter/enhancer activity during early myogenesis.

Myostatin (MSTN) is a strong inhibitor of skeletal muscle growth in human and other vertebrates. Its transcription is controlled by a proximal promoter/enhancer (Mstn P/E) containing a TATA box besides CREB, NF-Y, MEIS1 and FXR transcription factor binding sites (TFBSs), which are conserved throughout evolution. The aim of this work was to investigate the role of these TFBSs on Mstn P/E activity and evaluate the potential of their putative ligands as Mstn trans regulators. Mstn P/E mutant constructs were used to establish the role of conserved TFBSs using dual-luciferase assays. Expression analyses were performed by RT-PCR and in situ hybridization in C2C12 myoblasts and E10.5 mouse embryos, respectively. Our results revealed that CREB, NF-Y and MEIS1 sites are required to balance Mstn P/E activity, keeping Mstn transcription within basal levels during myoblast proliferation. Furthermore, our data showed that NF-Y site is essential, although not sufficient, to mediate Mstn P/E transcriptional activity. In turn, CREB and MEIS1 binding sites seem to depend on the presence of NF-Y site to induce Mstn P/E. FXR appears not to confer any effect on Mstn P/E activity, except in the absence of all other conserved TFBS. Accordingly, expression studies pointed to CREB, NF-Y and MEIS1 but not to FXR factors as possible regulators of Mstn transcription in the myogenic context. Altogether, our findings indicated that CREB, NF-Y and MEIS1 conserved sites are essential to control basal Mstn transcription during early myogenesis, possibly by interacting with these or other related factors.

Development of an intraoral device for social inclusion of a physically disabled patient.

The aim of this study is to describe the use of an intraoral assistive technology for a patient with idiopathic generalized muscular dystonia, presenting temporomandibular disorder and severe anterior tooth mobility and diastema. A multidisciplinary team developed an intraoral device to provide typing and painting functions, and promote relaxation of masticatory muscles without compromising the teeth and supporting tissue structures. The occlusal splint associated with the device promoted muscle relaxation and relief of the signs and symptoms of temporomandibular dysfunction, in this case with generalized muscle dystonia, allowing typing and painting with her mouth without causing tooth mobility or occlusal alteration. This intraoral device has low cost, easy adaptation and was efficient in TMD symptoms. Furthermore, the patient returned to her rehabilitation allowing performance of her duties without compromising dental structures, facilitating the social and the digital inclusion.

Oral changes stemming from hemangioma of the tongue.

Hemangiomas are among the most common tumors found in children and are characterized by an excess of blood vessels. They most often affect the area of the head and neck, occur with greater frequency among women and Caucasians, and can be found in the oral cavity-especially on the lips, tongue, or mucosa. Clinically, hemangiomas present as asymptomatic red or blue-colored lesions that grow rapidly and are capable of spontaneous regression. When they are found on the tongue, they can result in clinical problems as well as recurrent trauma due to biting of the tongue and tooth-brushing, resulting in bleeding, obstruction of the upper airways, and difficulty with chewing, deglutition, and speaking. The purpose of this article was to present a case study of a 4-year-old child with a diagnosis of hemangioma of the tongue, emphasizing the oral changes found as a result of this lesion, as well as the dental treatment used to minimize these changes.

Relationship between diurnal grazing time and herbage intake in dairy cows in rotational grazing / Inter-relação entre o tempo de pastejo diurno e o consumo de forragem em vacas leiteiras em pastejo rotativo

The aim of this study was describe the relationship between grazing time and herbage intake and identify tools to grazing management of dairy cows grazing Italian ryegrass (Lolium multiflorum Lam.) on a rotational grazing method. Six dairy cows in mid-lactation period were allowed to graze paddocks during three grazing cycles. During each cycle cows grazed two paddocks with 9 days of occupation by paddock and an herbage allowance of 30kg DM cow-1 day-1. Measurements were made in the last 9 days of each period and during intervals between cycles cows grazed an adjacent area with a mixed of temperate species. It was compared three grazing cycles and cows eating similar herbage amount with different daily grazing time. Independently of herbage intake, daily grazing time increased 12min by cm of the reduction on leaf height. Reductions on efficiency to graze are clearly associated to structural traits of canopy as proximity to ground level and stems + pseudo-stems content on the graze layer. In conclusion, under rotational grazing, daily grazing time is strongly associated with leaf height in the grazing layer, but it is not a good indicator of DM herbage intake. Structural traits of canopy are clearly associated with efficiency to graze, independently of daily herbage intake.

Objetivou-se descrever a relação entre o tempo de pastejo e o consumo de forragem e identificar possíveis indicadores de manejo para vacas leiteiras em pastos de azevém (Lolium multiflorum Lam.) no método rotativo. Foram utilizadas seis vacas leiteiras no terço médio de lactação durante três ciclos de pastejo. Em cada ciclo, os animais tiveram acesso a dois piquetes com nove dias de ocupação e oferta de forragem de 30kg MS vaca-1 dia-1. As medidas foram realizadas nos últimos nove dias de cada ciclo e, nos intervalos entre ciclos, os animais permaneceram em área adjacente com acesso a uma mistura de espécies forrageiras de clima temperado. Comparando os três ciclos, foi possível observar que as vacas obtiveram semelhante consumo de forragem com diferentes tempos de pastejo diário. Independente da quantidade de forragem ingerida, o tempo de pastejo diário aumentou 12min por cm de redução na altura residual de lâminas foliares e reduções na eficiência de pastejo foram claramente associadas a características estruturais da pastagem, como, a proximidade ao solo e a proporção de colmos + pseudocolmos no estrato pastejado. Em conclusão, sob pastejo rotativo, o tempo de pastejo está intimamente associado com a altura residual de folhas, mas não é um bom indicador do consumo de forragem. As características estruturais do pasto são claramente associadas à eficiência de pastejo, independente do consumo diário de forragem.

Effect of blood contamination on the shear bond strength at resin/dentin interface in primary teeth.

PURPOSE: To assess in vitro the shear bond strength at the resin/dentin interface in primary teeth after contamination with fresh human blood. METHODS: 75 crowns of primary molars were embedded in acrylic resin and mechanically ground to expose a flat dentin surface. The specimens were randomly assigned to five groups (n=15), according to the surface treatment. Group 1 (control) had no blood contamination. The other groups were blood-contaminated and subjected to different post-contamination protocols: in Group 2, the surfaces were rinsed with water; in Group 3, the surfaces were air-dried; in Group 4, the surfaces were rinsed and air-dried; and in Group 5, no post-contamination treatment was done. In all groups, a 3-mm dentin bonding site was demarcated, Single Bond adhesive system was applied and resin composite cylinders were bonded. After 24 hours in distilled water, shear bond strength was tested at a crosshead speed of 0.5 mm/minute. RESULTS: Means (in MPa) were: Group 1: 7.1 (+/- 4.2); Group 2: 4.0 (+/- 1.8); Group 3: 0.9 (+/- 0.7); Group 4: 3.9 (+/- 2.2) and Group 5: 1.3 (+/- 1.5). Data were analyzed statistically by the Kruskal-Wallis test at 5% significance level. Groups 2 and 4 were similar to each other (P > 0.05) and both ware similar to Group 1 (P > 0.05). These groups (2, 3 and 4) had statistically significantly higher bond strengths than Groups 3 and 5 (P < 0.05). Blood contamination negatively affected the shear bond strength to primary tooth dentin. Among the blood-contaminated groups, water-rinsed specimens had higher bond strengths than those that were exclusively air-dried or not submitted to any post-contamination protocol before adhesive application.

Shear bond strength to primary enamel: influence of Er:YAG laser irradiation distance.

PURPOSE: The purpose of this study was to evaluate in vitro the influence of Er:YAG laser irradiation distance on the shear bond strength of an adhesive restorative system to primary enamel. METHODS: Fifty buccal surfaces of extracted human canines were ground and divided into 5 groups (N=10). The control group was etched with 35% phosphoric acid (CA). In the lased groups, the enamel surface treatment was performed with the Er:YAG laser (80mJ/2Hz) by varying the irradiation distance (12, 14, 16, and 17 mm), followed by acid etching. An adhesive agent (Single Bond) was applied on the bonding sites, and resinous cylinders (Filtek Z250) were prepared. Shear bond strength tests were performed in a universal testing machine (0.5 mm/minute). Failure mode was assessed using a X40 magnification stereomicroscope. Data were submitted to statistical analysis by analysis of variance. RESULTS: The means in MPa were: (1) CA=18.76 (+/-6.68); (2) 12 mm=12.73 (+/-5.46); (3) 14 mm=15.9 (+/-6.81); (4) 16 mm=20.1 (+/-6.94); and (5) 17 mm=15.15 (+/-6.81). There was no statistically significant difference (P<.05) among the tested groups. CONCLUSION: The different Er:YAG laser distance irradiations did not influence the adhesive resistance of the resinous system to enamel, even when compared with the control group (acid etching solely).