Frictional Melting in Hydrothermal Fluid-Rich Faults: Field and Experimental Evidence From the Bolfín Fault Zone (Chile).

Tectonic pseudotachylytes are thought to be unique to certain water-deficient seismogenic environments and their presence is considered to be rare in the geological record. Here, we present field and experimental evidence that frictional melting can occur in hydrothermal fluid-rich faults hosted in the continental crust. Pseudotachylytes were found in the >40 km-long Bolfín Fault Zone of the Atacama Fault System, within two ca. 1 m-thick (ultra)cataclastic strands hosted in a damage-zone made of chlorite-epidote-rich hydrothermally altered tonalite. This alteration state indicates that hydrothermal fluids were active during the fault development. Pseudotachylytes, characterized by presenting amygdales, cut and are cut by chlorite-, epidote- and calcite-bearing veins. In turn, crosscutting relationship with the hydrothermal veins indicates pseudotachylytes were formed during this period of fluid activity. Rotary shear experiments conducted on bare surfaces of hydrothermally altered rocks at seismic slip velocities (3 m s-1) resulted in the production of vesiculated pseudotachylytes both at dry and water-pressurized conditions, with melt lubrication as the primary mechanism for fault dynamic weakening. The presented evidence challenges the common hypothesis that pseudotachylytes are limited to fluid-deficient environments, and gives insights into the ancient seismic activity of the system. Both field observations and experimental evidence, indicate that pseudotachylytes may easily be produced in hydrothermal environments, and could be a common co-seismic fault product. Consequently, melt lubrication could be considered one of the most efficient seismic dynamic weakening mechanisms in crystalline basement rocks of the continental crust.

Fluid pressurisation and earthquake propagation in the Hikurangi subduction zone.

In subduction zones, seismic slip at shallow crustal depths can lead to the generation of tsunamis. Large slip displacements during tsunamogenic earthquakes are attributed to the low coseismic shear strength of the fluid-saturated and non-lithified clay-rich fault rocks. However, because of experimental challenges in confining these materials, the physical processes responsible for the coseismic reduction in fault shear strength are poorly understood. Using a novel experimental setup, we measured pore fluid pressure during simulated seismic slip in clay-rich materials sampled from the deep oceanic drilling of the Papaku thrust (Hikurangi subduction zone, New Zealand). Here, we show that at seismic velocity, shear-induced dilatancy is followed by pressurisation of fluids. The thermal and mechanical pressurisation of fluids, enhanced by the low permeability of the fault, reduces the energy required to propagate earthquake rupture. We suggest that fluid-saturated clay-rich sediments, occurring at shallow depth in subduction zones, can promote earthquake rupture propagation and slip because of their low permeability and tendency to pressurise when sheared at seismic slip velocities.

The role of bone anabolic drugs in the management of periodontitis: a scoping review.

The aim of this scoping review was to summarise current knowledge about the effects of bone anabolic drugs on periodontitis, in order to identify new therapeutic strategies for preventing disease progression and reducing tooth loss. A technical expert panel (TEP) was established of 11 medical specialists, including periodontists and bone specialists that followed the PRISMA-ScR model to perform the scoping review and considered for eligibility both pre-clinical and clinical studies published in the English language up to September 2020. 716 items were initially found. After duplicate removal and screening of articles for eligibility criteria, 25 articles published between 2001 and 2019 were selected. Only studies concerning teriparatide, strontium ranelate, sclerostin antibodies and DKK1 antibodies met the eligibility criteria. In particular, only for teriparatide were there both clinical studies and experimental studies available, while for other bone anabolic drugs only animal studies were found. Available evidence about the use of bone anabolic drugs in periodontology demonstrates beneficial effects of these agents on biological pathways and histological parameters involved in periodontal tissue regeneration that suggest relevant clinical implications for the management of periodontitis.

New insights on metal allergy in total joint arthroplasty.

Metal allergy is an uncommon and not completely understood cause of failure in total joint arthroplasty (TJA). However, either immunopathology neither histologic studies clarified the mechanisms through which the metal ions could lead to the complications related to them. The lack of evidence around this topic also reflects the difficulties to diagnose the MRP in TJA. In fact, the diagnosis is generally based on the exclusion of other causes. Currently, skin-patch testing and lymphocyte transformation test (LTT) are being commonly used to investigate about metal hypersensitivity and a delayed type-IV hypersensitivity is the immuno-histologic response to metals involved in TJA loosening. A review of the recent publications about this topic has been made focusing on immunology, histopathology, and clinics to better understand a still debated topic in orthopedic practice.

Two-stage reimplantation in periprosthetic knee infection.

OBJECTIVE: The increasing number of total knee arthroplasties performed yearly worldwide has resulted in a concomitant rise in bacterial infections. Two-stage reimplantation has been reported as the most successful method of treating periprosthetic knee infections. The purpose of this study was to describe all the phases of the two-stage reimplantation and to review the literature regarding the topic. MATERIALS AND METHODS: Most significant and recent papers about the management of periprosthetic knee infection through a two-stage reimplantation protocol were carefully analysed and reviewed. Our personal experience, previously published, with two-stage-reimplantation protocol was also briefly reported. RESULTS: Two-stage reimplantation has been reported as the most successful method of treating periprosthetic knee infections. The strategy of using an antibiotic-loaded cement spacer and intravenous antibiotics with delayed exchange arthroplasty is actually considered the state-of-the-art, with a reported success rate of 88-96%. The two-stage protocol has been reported as a viable option also for patients with a periprosthetic knee infection by multidrug-resistant organisms. On the other hand, open debridement with polyethylene exchange and single-stage reimplantation have been reported effective only in selective case series involving acute infections by low-virulence organisms. CONCLUSIONS: The strategy that involves the use of cement spacer, intravenous antibiotic therapy, and successive revision total knee implantation is nowadays considered the gold standard for the management of the periprosthetic knee infection. This treatment is actually considered the first choice not only for chronic but also for acute infections, especially in the presence of resistant bacteria.

Mechanical behaviour of fluid-lubricated faults.

Fluids are pervasive in fault zones cutting the Earth's crust; however, the effect of fluid viscosity on fault mechanics is mainly conjectured by theoretical models. We present friction experiments performed on both dry and fluid-permeated silicate and carbonate bearing-rocks, at normal effective stresses up to 20 MPa, with a slip-rate ranging between 10 µm/s and 1 m/s. Four different fluid viscosities were tested. We show that both static and dynamic friction coefficients decrease with viscosity and that dynamic friction depends on the dimensionless Sommerfeld number (S) as predicted by the elastohydrodynamic-lubrication theory (EHD).Under favourable conditions (depending on the fluid viscosity (η), co-seismic slip-rate (V), fault geometry (L/H02) and earthquake nucleation depth (∝σeff)), EHD might be an effective weakening mechanism during natural and induced earthquakes. However, at seismic slip-rate, the slip weakening distance (Dc) increases markedly for a range of fluid viscosities expected in the Earth, potentially favouring slow-slip rather than rupture propagation for small to moderate earthquakes.

Qué se debe saber en esclerosis múltiple: 16 preguntas prácticas / What one needs to know in multiple sclerosis: 16 practical questions

RESUMEN La esclerosis múltiple (EM) es la más frecuente de las enfermedades desmielinizantes del sistema nervioso central. Se trata de una patología compleja, con mecanismos fisiopatológicos aún no elucidados completamente y una presentación clínica variada. Es una entidad crónica, de alto costo para el sistema de salud, y usualmente se asocia a una importante discapacidad en los pacientes afectados. No existe una cura para la EM, sin embargo, se cuenta con más de 13 terapias modificadoras de la enfermedad que actúan en distintas dianas terapéuticas, enlentecen la progresión y mejoran el pronóstico. El objetivo de este escrito es presentar una actualización de EM, a través de 16 preguntas y temas controversiales. Estos 16 puntos responden a dudas puntuales y actuales, son presentados, analizados y, en los casos en los que la evidencia lo permite, se plantean recomendaciones. Las preguntas abordadas incluyen temas como diagnóstico, tratamiento, uso de nuevas tecnologías y manejo de los efectos adversos. Este escrito está destinado a neurólogos, médicos generales, residentes de neurología y cualquier profesional interesado en las enfermedades desmielinizantes.

SUMMARY Multiple sclerosis (MS) is the most common demyelinating disorder of the central nervous system. It is a complex disease, with a pathogenesis not fully understood and multiple clinical presentations. MS is a chronic disease, represents a great cost to healthcare systems and is often associated with a high burden of disability in patients. Despite the absence of a cure, there are at least13 disease-modifying therapies that act on different targets of the pathogenic process. The main purpose of this review is to solve 16 controversial and current topics in MS. These 16 topics are analysed, and when there is enough evidence, we issue recommendations. The topics include diagnosis, treatment, use of new technologies in MS, and medication side effects. This paper is meant for neurologists, neurology residents, general physicians and any other healthcare personnel interested in demyelinating diseases.

Subseismic to Seismic Slip in Smectite Clay Nanofoliation.

Smectite clays are the main constituent of slipping zones found in subduction zone faults at shallow depth (e.g., <1-km depth in the Japan Trench) and in the decollements of large landslides (e.g., 1963 landslide, Vajont, Italy). Therefore, deformation processes in smectite clays may control the mechanical behavior from slow creep to fast accelerations and slip during earthquakes and landslides. Here, we use (1) laboratory experiments to investigate the mechanical behavior of partly water-saturated smectite-rich gouges sheared from subseismic to seismic slip rates V and (2) nanoscale microscopy to study the gouge fabric. At all slip rates, deformation localizes in volumes of the gouge layer that contain a "nanofoliation" consisting of anastomosing smectite crystals. "Seismic" nanofoliations produced at V = 0.01, 0.1, and 1.3 m/s are similar to "subseismic" nanofoliations obtained at V = 10-5 m/s. This similarity suggests that frictional slip along water-lubricated smectite grain boundaries and basal planes may occur from subseismic to seismic slip rates in natural smectite-rich faults. Thus, if water is available along smectite grain boundaries and basal planes, nanofoliations can develop from slow to fast slip rates. Still, when nanofoliations are found highly localized in a volume, they can be diagnostic of slip that occurred at rates equal or larger than 0.01 m/s. In such a case, they could be markers of past seismic events when found in natural fault rocks.

An empirically based steady state friction law and implications for fault stability.

Empirically based rate-and-state friction laws (RSFLs) have been proposed to model the dependence of friction forces with slip and time. The relevance of the RSFL for earthquake mechanics is that few constitutive parameters define critical conditions for fault stability (i.e., critical stiffness and frictional fault behavior). However, the RSFLs were determined from experiments conducted at subseismic slip rates (V < 1 cm/s), and their extrapolation to earthquake deformation conditions (V > 0.1 m/s) remains questionable on the basis of the experimental evidence of (1) large dynamic weakening and (2) activation of particular fault lubrication processes at seismic slip rates. Here we propose a modified RSFL (MFL) based on the review of a large published and unpublished data set of rock friction experiments performed with different testing machines. The MFL, valid at steady state conditions from subseismic to seismic slip rates (0.1 µm/s < V < 3 m/s), describes the initiation of a substantial velocity weakening in the 1-20 cm/s range resulting in a critical stiffness increase that creates a peak of potential instability in that velocity regime. The MFL leads to a new definition of fault frictional stability with implications for slip event styles and relevance for models of seismic rupture nucleation, propagation, and arrest.

G: Fracture energy, friction and dissipation in earthquakes.

Recent estimates of fracture energy G' in earthquakes show a power-law dependence with slip u which can be summarized as G' ∝ ua where a is a positive real slightly larger than one. For cracks with sliding friction, fracture energy can be equated to Gf : the post-failure integral of the dynamic weakening curve. If the dominant dissipative process in earthquakes is friction, G' and Gf should be comparable and show a similar scaling with slip. We test this hypothesis by analyzing experiments performed on various cohesive and non-cohesive rock types, under wet and dry conditions, with imposed deformation typical of seismic slip (normal stress of tens of MPa, target slip velocity > 1 m/s and fast accelerations ≈ 6.5 m/s2). The resulting fracture energy Gf is similar to the seismological estimates, with Gf and G' being comparable over most of the slip range. However, Gf appears to saturate after several meters of slip, while in most of the reported earthquake sequences, G' appears to increase further and surpasses Gf at large magnitudes. We analyze several possible causes of such discrepancy, in particular, additional off-fault damage in large natural earthquakes.

Morphology and mycelial growth rate of Pleurotus spp. strains from the Mexican mixtec region.

Two native Pleurotus spp. strains (white LB-050 and pale pink LB-051) were isolated from rotten tree trunks of cazahuate (Ipomoea murucoides) from the Mexican Mixtec Region. Both strains were chemically dedikaryotized to obtain their symmetrical monokaryotic components (neohaplonts). This was achieved employing homogenization time periods from 60 to 65 s, and 3 day incubation at 28 °C in a peptone-glucose solution (PGS). Pairing of compatible neohaplonts resulted in 56 hybrid strains which were classified into the four following hybrid types: (R(1-n)xB(1-n), R(1-n)xB(2-1), R(2-n)xB(1-n) and R(2-n)xB(2-1)). The mycelial growth of Pleurotus spp. monokaryotic and dikaryotic strains showed differences in texture (cottony or floccose), growth (scarce, regular or abundant), density (high, regular or low), and pigmentation (off-white, white or pale pink). To determine the rate and the amount of mycelium growth in malt extract agar at 28 °C, the diameter of the colony was measured every 24 h until the Petri dish was completely colonized. A linear model had the best fit to the mycelial growth kinetics. A direct relationship between mycelial morphology and growth rate was observed. Cottony mycelium presented significantly higher growth rates (p < 0.01) in comparison with floccose mycelium. Thus, mycelial morphology can be used as criterion to select which pairs must be used for optimizing compatible-mating studies. Hybrids resulting from cottony neohaplonts maintained the characteristically high growth rates of their parental strains with the hybrid R(1-n)xB(1-n) being faster than the latter.

Participación paterna en la experiencia del parto / Father involvement in childbirth

Introduction: Recent initiatives have promoted the participation of fathers in the early care of their children. Objective: To assess the results of a program to encourage parental involvement in childbirth. Parents of healthy term newborns were randomly allocated to participate either in the birth experience or control. Patients and Methods: The protocol included: to dry the skin, umbilical cord cutting off, weight, height, and finally give him/her to the mother for the skin-to-skin contact. Heart rate (HR), respiratory (RR) and temperature were evaluated one hour later. In the first outpatient clinic assessment, mothers completed a questionnaire. 127 fathers participated either in the birth experience or control. Results: 62 followed the protocol and 65 the control. Both newborn groups were comparable. Also were fathers in age, education and rurality; mothers in primiparity. Significant differences: night care (37/62, 10/65 59.6% vs 15.4%, p < 0.01); post prandial assistance (50/62, 14/65 80.6% vs 21.5%, p < 0.01); participation in bathing (38/62, 61.3% vs 15/65, 23.1%, p < 0.01); newborn visit upon arrival at home (46/62, 74.2% vs 22/65, 33.8%, p < 0.01); helping in crying episodes (42/62, 67.7% vs 17/65, 26.1%, p < 0.01). There was stability in HR, RR and temperature one hour postpartum. Only one case of complication among parents (fainting). Conclusions: There were more cases of early care behaviors among participating fathers at birth, even belonging to a discouraging socio cultural environment.

Introducción: Recientes iniciativas, han promovido la participación de los padres en los cuidados tempranos de sus hijos. Objetivo: Evaluar los resultados de un programa de estímulo a la participación paterna en el parto. Se incluyeron padres de RN de término sanos, asignados aleatoriamente para participar en la experiencia del parto o control. Pacientes y Metodos: El protocolo incluyó: secado de la piel, corte de cordón umbilical, peso, estatura, y finalmente, entrega a la madre para el contacto piel a piel. Se evaluó frecuencia cardiaca (FC), respiratoria (FR) y temperatura una hora después. En el primer control ambulatorio, las madres completaron un cuestionario. 127 padres participaron en la experiencia del parto o control. Resultados: 62 asignados al protocolo y 65 al control. Ambos grupos de RN resultaron comparables. También los padres, en edad, escolaridad, ruralidad, y las madres, en primiparidad. Diferencias significativas: asistencia nocturna (37/62, 59,6% vs 10/65, 15,4%, p < 0,01); post prandial (50/62, 80,6% vs 14/65, 21,5%, p < 0,01); participación en el baño (38/62, 61,3% vs 15/65, 23,1%, p < 0,01); visita al RN al llegar al domicilio (46/62, 74,2% vs 22/65, 33,8%, p < 0,01); ayuda ante episodios de llanto (42/62, 67,7% vs 17/65, 26,1%, p < 0,01). Hubo estabilidad en FC, FR y temperatura una hora post-parto. Sólo un caso de complicación entre los padres (lipotimia). Conclusiones: Hubo más conductas de interés en cuidados tempranos, entre los padres participantes en el parto, aún perteneciendo a un medio sociocultural que no las promueve ni facilita.

Morphology and mycelial growth rate of Pleurotus spp. strains from the Mexican mixtec region

Two native Pleurotus spp. strains (white LB-050 and pale pink LB-051) were isolated from rotten tree trunks of cazahuate (Ipomoea murucoides) from the Mexican Mixtec Region. Both strains were chemically dedikaryotized to obtain their symmetrical monokaryotic components (neohaplonts). This was achieved employing homogenization time periods from 60 to 65 s, and 3 day incubation at 28 °C in a peptone-glucose solution (PGS). Pairing of compatible neohaplonts resulted in 56 hybrid strains which were classified into the four following hybrid types: (R1-n xB1-n, R1-n xB2-1, R2-n xB1-n and R2-n xB2-1). The mycelial growth of Pleurotus spp. monokaryotic and dikaryotic strains showed differences in texture (cottony or floccose), growth (scarce, regular or abundant), density (high, regular or low), and pigmentation (off-white, white or pale pink). To determine the rate and the amount of mycelium growth in malt extract agar at 28 °C, the diameter of the colony was measured every 24 h until the Petri dish was completely colonized. A linear model had the best fit to the mycelial growth kinetics. A direct relationship between mycelial morphology and growth rate was observed. Cottony mycelium presented significantly higher growth rates (p < 0.01) in comparison with floccose mycelium. Thus, mycelial morphology can be used as criterion to select which pairs must be used for optimizing compatible-mating studies. Hybrids resulting from cottony neohaplonts maintained the characteristically high growth rates of their parental strains with the hybrid R1-n xB1-n being faster than the latter.

Reduced toxicity, myeloablative conditioning with BU, fludarabine, alemtuzumab and SCT from sibling donors in children with sickle cell disease.

BU and CY (BU/CY; 200 mg/kg) before HLA-matched sibling allo-SCT in children with sickle cell disease (SCD) is associated with ~85% EFS but is limited by the acute and late effects of BU/CY myeloablative conditioning. Alternatives include reduced toxicity but more immunosuppressive conditioning. We investigated in a prospective single institutional study, the safety and efficacy of a reduced-toxicity conditioning (RTC) regimen of BU 12.8-16 mg/kg, fludarabine 180 mg/m(2), alemtuzumab 54 mg/m(2) (BFA) before HLA-matched sibling donor transplantation in pediatric recipients with symptomatic SCD. Eighteen patients, median age 8.9 years (2.3-20.2), M/F 15/3, 15 sibling BM and 3 sibling cord blood (CB) were transplanted. Mean whole blood and erythroid donor chimerism was 91% and 88%, at days +100 and +365, respectively. Probability of grade II-IV acute GVHD was 17%. Two-year EFS and OS were both 100%. Neurological, pulmonary and cardiovascular function were stable or improved at 2 years. BFA RTC and HLA-matched sibling BM and CB allo-SCT in pediatric recipients result in excellent EFS, long-term donor chimerism, low incidence of GVHD and stable/improved organ function.

Dynamic weakening of serpentinite gouges and bare surfaces at seismic slip rates.

To investigate differences in the frictional behavior between initially bare rock surfaces of serpentinite and powdered serpentinite ("gouge") at subseismic to seismic slip rates, we conducted single-velocity step and multiple-velocity step friction experiments on an antigorite-rich and lizardite-rich serpentinite at slip rates (V) from 0.003 m/s to 6.5 m/s, sliding displacements up to 1.6 m, and normal stresses (σn ) up to 22 MPa for gouge and 97 MPa for bare surfaces. Nominal steady state friction values (µnss) in gouge at V = 1 m/s are larger than in bare surfaces for all σn tested and demonstrate a strong σn dependence; µnss decreased from 0.51 at 4.0 MPa to 0.39 at 22.4 MPa. Conversely, µnss values for bare surfaces remained ∼0.1 with increasing σn and V. Additionally, the velocity at the onset of frictional weakening and the amount of slip prior to weakening were orders of magnitude larger in gouge than in bare surfaces. Extrapolation of the normal stress dependence for µnss suggests that the behavior of antigorite gouge approaches that of bare surfaces at σn ≥ 60 MPa. X-ray diffraction revealed dehydration reaction products in samples that frictionally weakened. Microstructural analysis revealed highly localized slip zones with melt-like textures in some cases gouge experiments and in all bare surfaces experiments for V ≥ 1 m/s. One-dimensional thermal modeling indicates that flash heating causes frictional weakening in both bare surfaces and gouge. Friction values for gouge decrease at higher velocities and after longer displacements than bare surfaces because strain is more distributed. KEY POINTS: Gouge friction approaches that of bare surfaces at high normal stressDehydration reactions and bulk melting in serpentinite in < 1 m of slipFlash heating causes dynamic frictional weakening in gouge and bare surfaces.

Estenosis bronquial congénita, papel de las imágenes en el diagnóstico: reporte de un caso / Congenital bronchial stenosis, the role of imaging in the diagnosis: a case report

En este artículo se reporta el caso de un lactante menor de 2 meses de edad que a los 15 días de nacido presentó estridor y dificultad respiratoria, por lo que consultó a una clínica de primer nivel en donde se le realizó radiografía de tórax, en la cual se documentó la presencia de una hiperinfiación del campo pulmonar derecho. Se realizó una fibrobroncoscopía óptica (FBO) que fue reportada como normal y una gammagrafía de ventilación/perfusión que reportó una hipoplasia pulmonar derecha. Fue manejado con oxígeno suplementario y terapias respiratorias sin mejoría clínica, motivo por el cual fue trasladado a nuestra institución para manejo especializado. Con el fin de obtener un mapa vascular pre quirúrgico, se realizó una angiografía pulmonar por tomografía (Figura 2) reconstrucciones con mínima intensidad de proyección (Figura 3) y broncoscopía virtual (BV) multicorte (Figuras 4 y 5) documentándose una estenosis del bronquio fuente derecho, producida por un repliegue de la pared bronquial y con efecto de válvula que producía una hiperinsufiación secundaria del pulmón derecho. Estos hallazgos fueron confirmados en la cirugía correctiva.

This article describes the case of an infant under 2 months old, who at 15 days of age presented stridor and respiratory distress, a chest X-ray was performed which reported the presence of a hyperinflation of the right lung field. A fiberoptic bronchoscopy (FBO) was performed which resulted normal and a ventilation/perfusion gammagraph showed a right lung hypoplasia. The infant was treated with additional oxygen and respiratory therapy without clinical. In order to obtain a pre-surgical vascular map, a multislice CT angiography and virtual bronchoscopy were performed, documenting a right bronchial stenosis produced by a fold of the bronchial wall and with valve effect which produced a secondary hyperinsufflation of the right lung. These findings were confirmed in corrective surgery.

Effect evaluation of the feeding, and administration of omeprazole pelletsorally on gastric juice pH in adult horses / Evaluación del efecto de la alimentación y de la administración deomeprazol en pellets vía oral sobre el pH del jugo gástrico en equinosadultos / Avaliação do efeito da alimentação, e administração de omeprazole pelletspor via oral no pH do suco gástrico em cabalhos adultos

The aim of this study was to determine the omeprazol treatment effect on equine gastric fluid pH with food andwithout food administering for the duration of the experiment. To carry this project out, 7 animals were chosenbetween the ages of 3 and 10 (2 males and 5 females) from the Centro de Veterinaria y Zootecnia - CES. In thecontrolled treatment they received 200 ml of physiological saline and were treated using omeprazol pellets whichwere administered in a single dose of 4 mg/kg via a nasogastric insertion, and in two groups with or without foodduring the treatment. Gastric pHs were measured at 0 hour (fasting before treatment) and then at hours 3, 5, 7, 9,11 and 24 after treatment. In animals consuming food, both treatments showed post treatment gastric pH increases,which can be explained by the ad libitumn food management in both treatments, which may increasing post prandialpH. In fasting animals, we observed that in the controlled treatment the pH was maintained at very low levels atall measurement times, while in the omeprazol treatment the pH increased significantly. These results show thattreatment with omeprazol pellets at a dose of 4 mg/kg via nasogastric insertion increased gastric pH in healthyanimals that are not eating food and that this effect was similar to them being administered food.

El objetivo de este estudio fue determinar el efecto del tratamiento con omeprazol sobre el pH del fluido gástrico en equinos, con la administración del alimento y sin ella. Para llevar a cabo este proyecto se eligieron siete animalesentre los 3 y 10 años de edad (2 machos y 5 hembras) del Centro de Veterinaria y Zootecnia – CES. El tratamientocon omeprazol se administró en pellets a una dosis única de 4 mg/kg, por vía nasogástrica, para los grupos cono sin alimento. Para el tratamiento control, se administraron 200 ml de solución salina fisiológica. En todos lostratamientos se midieron los pHs gástricos a la hora 0 (ayunas antes del tratamiento) y luego a las horas 3, 5, 7, 9, 11 y 24, postratamiento. Los animales que consumieron alimento con y sin omeprazol presentaron aumentos de pHgástrico postratamiento, lo que se puede explicar por el sumistro de heno ad libitum en ambos tratamientos. En losanimales en ayuno se observó que en el tratamiento control, el pH se mantuvo en niveles muy bajos en todas las horasde medición, mientras que en el tratamiento con omeprazol, el pH aumentó notablemente. Los resultados muestran que el tratamiento con pellets de omeprazol a una dosis de 4 mg/kg vía nasogástrica aumentó el pH gástrico en animales sanos que no están consumiendo alimento y que este efecto fue similar que cuando se administró el mismo.

A resistência é o mecanismo pelo qual a bactéria pode diminuir a ação dos agentes antimicrobianos de formanatural ou adquirida; dentro das causas mais frequentes está a utilização indiscriminada destes agentes em pacienteshumanos e produções pecuárias. Desde 1990 tem identificado novas cepas resistentes de bactérias que originaramdoenças zoonóticas emergentes. Dentro destas a zoonose, a salmonelose é considerada a doença mais difundida anível mundial, a ampla distribuição na natureza entre animais silvestres, domésticos e o meio ambiente, produz umarápida propagação de seus mais de 2500 sorotipos no homem. Contudo, a grande preocupação pela infecção com esteinteiro patógeno é devido aos cada vez mais elevados fracassos nos tratamentos com antimicrobianos convencionais,ocasionados pela alta resistência bacteriana a estes fármacos. O presente artigo é uma revisão sobre a problemáticaque gerou a resistência de Salmonella no homem e os animais, contem também estratégias de prevenção e controledeste fenômeno, que está distante de terminar e permitem o fortalecimento da saúde pública.

Cloning and spatiotemporal expression of RIC-8 in Xenopus embryogenesis.

RIC-8 is a highly conserved protein that promotes G protein signaling as it acts as a Guanine nucleotide Exchanging Factor (GEF) over a subset of Gα subunits. In invertebrates, RIC-8 plays crucial roles in synaptic transmission as well as in asymmetric cell division. As a first step to address further studies on RIC-8 function in vertebrates, here we have cloned a ric-8 gene from Xenopus tropicalis (xtric-8) and determined its spatiotemporal expression pattern throughout embryogenesis. The xtric-8 transcript is expressed maternally and zygotically and, as development proceeds, it shows a dynamic expression pattern. At early developmental stages, xtric-8 is expressed in the animal hemisphere, whereas its expression is later restricted to neural tissues, such as the neural tube and the brain, as well as in the eye and neural crest-derived structures, including those of the craniofacial region. Together, our findings suggest that RIC-8 functions are related to the development of the nervous system.

Fault lubrication during earthquakes.

The determination of rock friction at seismic slip rates (about 1 m s(-1)) is of paramount importance in earthquake mechanics, as fault friction controls the stress drop, the mechanical work and the frictional heat generated during slip. Given the difficulty in determining friction by seismological methods, elucidating constraints are derived from experimental studies. Here we review a large set of published and unpublished experiments (∼300) performed in rotary shear apparatus at slip rates of 0.1-2.6 m s(-1). The experiments indicate a significant decrease in friction (of up to one order of magnitude), which we term fault lubrication, both for cohesive (silicate-built, quartz-built and carbonate-built) rocks and non-cohesive rocks (clay-rich, anhydrite, gypsum and dolomite gouges) typical of crustal seismogenic sources. The available mechanical work and the associated temperature rise in the slipping zone trigger a number of physicochemical processes (gelification, decarbonation and dehydration reactions, melting and so on) whose products are responsible for fault lubrication. The similarity between (1) experimental and natural fault products and (2) mechanical work measures resulting from these laboratory experiments and seismological estimates suggests that it is reasonable to extrapolate experimental data to conditions typical of earthquake nucleation depths (7-15 km). It seems that faults are lubricated during earthquakes, irrespective of the fault rock composition and of the specific weakening mechanism involved.

Effects of saliva substitutes on oral status in patients with Type 2 diabetes.

AIMS: To assess oral status in a sample of Type 2 diabetic patients before and after therapy with saliva substitutes and oral status in a control group of diabetic patients who were not given saliva substitutes. METHODS: Salivary flow rate was determined in 134 patients (mean age 47.9 ± 2.9 years) with Type 2 diabetes. Mean salivary rate was significantly low compared with a healthy control group. The sample of 134 patients was randomly divided into two groups of 67 people each. One group was given immunologically active salivary substitutes for 6 months, the other group was given nothing. Each patient of the two groups underwent a dental and periodontal examination at the beginning of the study and 6 months later. RESULTS: As regards carious teeth and teeth loss, there was no statistical difference between the first group after 6 months of treatment with salivary substitutes and the control group (P>0.01). Salivary substitutes did not significantly reduce the periodontal disease (P>0.01). In the group treated with salivary substitutes, after 6 months of therapy, the average dental plaque index decreased from 2.3 ± 0.73 to 1.6 ± 0.56, patients with gingivitis decreased from 66 to 43% and patients with positive yeast counts decreased from 60 to 37%. These differences were statistically significant (P<0.01). CONCLUSIONS: In Type 2 diabetes, in the case of hyposalivation, a therapy with immunologically active saliva substitutes can be of help in reducing the amount of plaque, gingivitis and positive yeast counts.