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1.
Plant Cell Physiol ; 59(1): e5, 2018 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-29228298

RESUMEN

SeedStor (https://www.seedstor.ac.uk) acts as the publicly available database for the seed collections held by the Germplasm Resources Unit (GRU) based at the John Innes Centre, Norwich, UK. The GRU is a national capability supported by the Biotechnology and Biological Sciences Research Council (BBSRC). The GRU curates germplasm collections of a range of temperate cereal, legume and Brassica crops and their associated wild relatives, as well as precise genetic stocks, near-isogenic lines and mapping populations. With >35,000 accessions, the GRU forms part of the UK's plant conservation contribution to the Multilateral System (MLS) of the International Treaty for Plant Genetic Resources for Food and Agriculture (ITPGRFA) for wheat, barley, oat and pea. SeedStor is a fully searchable system that allows our various collections to be browsed species by species through to complicated multipart phenotype criteria-driven queries. The results from these searches can be downloaded for later analysis or used to order germplasm via our shopping cart. The user community for SeedStor is the plant science research community, plant breeders, specialist growers, hobby farmers and amateur gardeners, and educationalists. Furthermore, SeedStor is much more than a database; it has been developed to act internally as a Germplasm Information Management System that allows team members to track and process germplasm requests, determine regeneration priorities, handle cost recovery and Material Transfer Agreement paperwork, manage the Seed Store holdings and easily report on a wide range of the aforementioned tasks.


Asunto(s)
Biología Computacional/métodos , Bases de Datos Genéticas , Gestión de la Información/métodos , Semillas/genética , Brassica/genética , Productos Agrícolas/genética , Minería de Datos/métodos , Grano Comestible/genética , Fabaceae/genética , Internet , Fenotipo
2.
J Exp Bot ; 64(7): 1783-93, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23420880

RESUMEN

Flowering is a critical period in the life cycle of flowering plant species, resulting in an irreversible commitment of significant resources. Wheat is photoperiod sensitive, flowering only when daylength surpasses a critical length; however, photoperiod insensitivity (PI) has been selected by plant breeders for >40 years to enhance yield in certain environments. Control of flowering time has been greatly facilitated by the development of molecular markers for the Photoperiod-1 (Ppd-1) homeoloci, on the group 2 chromosomes. In the current study, an allelic series of BC2F4 lines in the winter wheat cultivars 'Robigus' and 'Alchemy' was developed to elucidate the influence on flowering of eight gene variants from the B- and D-genomes of bread wheat and the A-genome of durum wheat. Allele effects were tested in short, natural, and extended photoperiods in the field and controlled environments. Across genetic background and treatment, the D-genome PI allele, Ppd-D1a, had a more potent effect on reducing flowering time than Ppd-B1a. However, there was significant donor allele effect for both Ppd-D1a and Ppd-B1a, suggesting the presence of linked modifier genes and/or additional sources of latent sensitivity. Development of Ppd-A1a BC2F4 lines derived from synthetic hexaploid wheat provided an opportunity to compare directly the flowering time effect of the A-genome allele from durum with the B- and D-genome variants from bread wheat for the first time. Analyses indicated that the reducing effect of Ppd-A1a is comparable with that of Ppd-D1a, confirming it as a useful alternative source of PI.


Asunto(s)
Alelos , Fotoperiodo , Proteínas de Plantas/metabolismo , Triticum/genética , Proteínas de Plantas/genética , Triticum/metabolismo , Triticum/fisiología
3.
J Biomed Mater Res B Appl Biomater ; 82(2): 460-70, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17245749

RESUMEN

COLLOSS and COLLOSS E are osteoinductive bone void fillers consisting of bone collagen and noncollagenous proteins from bovine and equine bone, respectively. The aim of this study was to compare COLLOSS, COLLOSS E, iliac bone autograft, sintered beta tricalcium phosphate (beta-TCP; OSSAPLAST), and COLLOSS E plus OSSAPLAST. Materials were placed for 4, 8, or 24 weeks in 5-mm cortical bone defects in sheep long bones. Histological sections in a plane perpendicular to the long axis of the bone were used to measure the total repair area (original defect plus callus) and the area of bone within the total repair area. The incidence of defect union was also evaluated. At 4 and 8 weeks, defects treated with COLLOSS and COLLOSS E with or without OSSAPLAST had total repair and bone areas equivalent to autograft, and larger than OSSAPLAST-treated defects. At 8 weeks, the incidence of defect union was higher in defects treated with autograft or COLLOSS E plus OSSAPLAST than in untreated defects. At 24 weeks, the incidence of union was 100% in all treatment groups and 0% in untreated defects. The incidence of union was related to the degree of remodeling between 8 and 24 weeks. This was greater in all treated than nontreated defects. In conclusion, COLLOSS and COLLOSS E were equivalent to each other and to autograft, and superior to beta-TCP, in this study model.


Asunto(s)
Proteínas Morfogenéticas Óseas/administración & dosificación , Regeneración Ósea/efectos de los fármacos , Sustitutos de Huesos/administración & dosificación , Fosfatos de Calcio/administración & dosificación , Colágeno/administración & dosificación , Tibia/efectos de los fármacos , Animales , Femenino , Ilion/trasplante , Oveja Doméstica , Tibia/citología , Tibia/lesiones , Trasplante Autólogo
4.
J Bone Joint Surg Br ; 88(7): 960-6, 2006 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-16799005

RESUMEN

Critical size defects in ovine tibiae, stabilised with intramedullary interlocking nails, were used to assess whether the addition of carboxymethylcellulose to the standard osteogenic protein-1 (OP-1/BMP-7) implant would affect the implant's efficacy for bone regeneration. The biomaterial carriers were a 'putty' carrier of carboxymethylcellulose and bovine-derived type-I collagen (OPP) or the standard with collagen alone (OPC). These two treatments were also compared to "ungrafted" negative controls. Efficacy of regeneration was determined using radiological, biomechanical and histological evaluations after four months of healing. The defects, filled with OPP and OPC, demonstrated radiodense material spanning the defect after one month of healing, with radiographic evidence of recorticalisation and remodelling by two months. The OPP and OPC treatment groups had equivalent structural and material properties that were significantly greater than those in the ungrafted controls. The structural properties of the OPP- and OPC-treated limbs were equivalent to those of the contralateral untreated limb (p > 0.05), yet material properties were inferior (p < 0.05). Histopathology revealed no residual inflammatory response to the biomaterial carriers or OP-1. The OPP- and OPC-treated animals had 60% to 85% lamellar bone within the defect, and less than 25% of the regenerate was composed of fibrous tissue. The defects in the untreated control animals contained less than 40% lamellar bone and more than 60% was fibrous tissue, creating full cortical thickness defects. In our studies carboxymethylcellulose did not adversely affect the capacity of the standard OP-1 implant for regenerating bone.


Asunto(s)
Materiales Biocompatibles/administración & dosificación , Proteínas Morfogenéticas Óseas/administración & dosificación , Regeneración Ósea/efectos de los fármacos , Carboximetilcelulosa de Sodio/administración & dosificación , Factor de Crecimiento Transformador beta/administración & dosificación , Animales , Fenómenos Biomecánicos , Enfermedades Óseas/tratamiento farmacológico , Enfermedades Óseas/patología , Enfermedades Óseas/fisiopatología , Proteína Morfogenética Ósea 7 , Colágeno Tipo I/administración & dosificación , Modelos Animales de Enfermedad , Portadores de Fármacos , Implantes de Medicamentos , Femenino , Radiografía , Proteínas Recombinantes/administración & dosificación , Ovinos , Tibia/diagnóstico por imagen , Tibia/patología , Tibia/fisiopatología
5.
Iowa Orthop J ; 25: 95-101, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16089080

RESUMEN

Traditionally, arthroscopic management of shoulder instability has been reserved for patients with isolated Bankart lesions without any capsular laxity or injury. To date, there are no animal studies evaluating the healing potential of capsular plication and/or capsulo-labral repair. The purpose of this in vivo animal study was to determine if the histological capsular healing of an open capsular plication simulating an arthroscopic plication is equivalent to the more traditional open capsular shift involving cutting and advancing the capsule. Twenty-six skeletally mature sheep were randomized to either an open capsular plication simulating arthroscopic plication (n = 13), or an open traditional capsular shift (n = 13). A sham operation (n = 4) was also performed involving exposure to visualize the capsule. Normal non-operated control shoulders were also analyzed. A pathologist blinded to the treatment evaluated both hematoxylin and eosin (H&E) sections and polarized light microscopy. Qualitative scoring evaluated fibrosis, mucinous degeneration, fat necrosis, granuloma formation, vascularity, inflammatory infiltrate and hemosiderin (0 to 3 points). Both the capsular plication and open shift groups demonstrated healing by fibrosis at the site of surgical manipulation. There were no statistical differences in the capsular healing responses between the two groups with regard to fibrosis, granuloma formation and vascularity. The open shift group demonstrated significantly more mucinous degeneration (p = 0.038). Fat necrosis was present in 4/13 specimens in the open shift group and none in the capsular plication specimens. Both groups demonstrated disorganized collagen formation under polarized light microscopy. There were no differences between non-operated control specimens and sham surgery specimens. Our findings support the hypothesis that histologic capsular healing is equivalent between the plication group and the open shift group. In addition, the open shift group demonstrated significantly more changes indicative of tissue injury. This basic science model confirms capsular healing after simulated arthroscopic plication, providing support for arthroscopic capsular plication in practice.


Asunto(s)
Artroscopía , Cápsula Articular/cirugía , Inestabilidad de la Articulación/cirugía , Articulación del Hombro/cirugía , Animales , Necrosis Grasa/patología , Femenino , Fibrosis , Cápsula Articular/patología , Inestabilidad de la Articulación/patología , Distribución Aleatoria , Ovinos , Cicatrización de Heridas
6.
J Orthop Res ; 23(4): 869-76, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-16023002

RESUMEN

Changes in bone mineral density associated with estrogen depletion in humans do not account for all of the associated change in fracture risk, and it is possible that some of this variation may lie in changes of other aspects of bone quality. The purpose of this study was to investigate changes in viscoelastic behavior of compact bone that may be associated with estrogen depletion. Changes in compact bone viscoelastic properties associated with three years of ovariectomy were investigated with dynamic mechanical analysis (low-amplitude 3-point bending at frequencies of 1-20 Hz) using beams milled from the diaphysis of the ovine radius. The viscoelastic storage modulus was significantly (5.2%) lower at the higher frequencies for the ovariectomized animals. The general anatomic variation in storage modulus, in which cranial sectors had higher values than caudal sectors, did not change with ovariectomy. The loss tangent (tandelta, a measure of damping) was also greatly decreased (up to 83%) at high frequencies in the ovariectomized animals. Anatomic variation in tandelta at low (6-12 Hz) frequencies (cranial and caudal sectors having higher values than lateral or medial sectors) was enhanced with ovariectomy. Changes in viscoelastic properties associated with long-term estrogen depletion could be responsible for a significant reduction in the toughness or strength of a bone without concomitant changes in screening modalities used to evaluate bone quality (e.g., DXA, QCT, QUA).


Asunto(s)
Densidad Ósea , Ovariectomía/efectos adversos , Radio (Anatomía)/patología , Cúbito/patología , Animales , Elasticidad , Estrógenos/fisiología , Femenino , Radio (Anatomía)/fisiología , Ovinos , Estrés Mecánico , Cúbito/fisiología
7.
Calcif Tissue Int ; 75(5): 431-7, 2004 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-15592799

RESUMEN

Dietary-induced metabolic acidosis (DIMA) may be a significant confounder in the development of osteoporosis. Diets that are acidifying are typically rich in proteins and grains and relatively poor in fruits and vegetables. Previous studies have not examined whether an interaction between estrogen depletion and DIMA have a compounded affect on bone mineral density loss. Sheep have been used successfully in previous studies to examine the interaction of bone turnover and ovariectomy. Therefore, the goal of this pilot study was to determine if bone mineral density (BMD) loss could be induced using DIMA in skeletally mature ovariectomized (OVX) ewes.


Asunto(s)
Acidosis/etiología , Densidad Ósea , Dieta , Ovariectomía , Alimentación Animal , Animales , Peso Corporal , Femenino , Proyectos Piloto , Ovinos
8.
Bone ; 35(3): 729-38, 2004 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-15336610

RESUMEN

Significant decreases in ovine compact bone viscoelastic properties (specifically, stress-rate sensitivity, and damping efficiency) are associated with three years of ovariectomy and are particularly evident at higher frequencies [Proc. Orthop. Res. Soc. 27 (2002) 89]. It is unclear what materials or architectural features of bone are responsible for either the viscoelastic properties themselves, or for the changes in those properties that were observed with estrogen depletion. In this study, we examined the relationship between these viscoelastic mechanical properties and features involving bone architecture (BV/TV), materials parameters (ash density, %mineralization), and histologic evidence of remodeling (%remodeled, cement line interface). The extent of mineralization was inversely proportional to the material's efficiency in damping stress oscillations. The damping characteristics of bone material from ovariectomized animals were significantly more sensitive to variation in mineralization than was bone from control animals. At low frequencies (6 Hz or less), increased histologic evidence of remodeling was positively correlated with increased damping efficiency. However, the dramatic decreases in stress-rate sensitivity that accompanied 3-year ovariectomy were seen throughout the bone structure and occurred even in areas with little or no secondary Haversian remodeling as well as in areas of complete remodeling. Taken together, these data suggest that, while the mineral component may modify the viscoelastic behavior of bone, the basic mechanism underlying bone viscoelastic behavior, and of the changes in that behavior with estrogen depletion, reside in a non-mineral component of the bone that can be significantly altered in the absence of secondary remodeling.


Asunto(s)
Remodelación Ósea/fisiología , Calcificación Fisiológica/fisiología , Radio (Anatomía)/fisiología , Ovinos/fisiología , Cúbito/fisiología , Animales , Elasticidad , Femenino , Ovariectomía , Radio (Anatomía)/anatomía & histología , Ovinos/anatomía & histología , Cúbito/anatomía & histología , Viscosidad
9.
Maturitas ; 46(3): 231-8, 2003 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-14585527

RESUMEN

OBJECTIVES: To determine if ovariectomized ewes undergo periodic body temperature rises (hot flashes) similar to women at menopause. METHODS: Eighteen mature ewes were assigned to ovariectomy (OVX), ovariectomy+17 beta-estradiol implant (OVXE) or Sham. Electronic temperature loggers placed subcutaneously over the carotid artery and within the abdomen (core) and subcutaneously in the thigh and axilla (peripheral) were programmed to record body temperatures every 2.5 min for 59 days. Circadian rhythm changes were avoided by dividing readings into 1 h intervals. Hot flashes were defined as a 0.2 or 0.4 degrees C increase over the minimum temperature recorded for a 1 h interval for each sheep. RESULTS: Logger placement did not reflect core and peripheral temperatures. The carotid and abdominal sites were most useful. The percentage of readings considered HF at the carotid site was 63% OVX, 54% OVXE and 37% Sham (P<0.001), and at the abdominal site were 32% OVX, 15% OVE and 17% Sham (P<0.001). When only the first 7 days after ovariectomy were analyzed, the percentage of readings considered to be HF at the carotid site was 75% OVX, 63% OVXE, and 49% Sham (P<0.001), and at the abdominal site was 35% OVX, 15% OVXE and 17% Sham (P<0.001). CONCLUSIONS: Ovariectomy in the ewe does illicit changes in body temperature compared with control ewes, which may be interpreted as HF. However, shifts in the circadian rhythm were not apparent. Estradiol treatment led to milder and less frequent HF. Periodic HF in species other than rats have heretofore not been reported.


Asunto(s)
Regulación de la Temperatura Corporal/fisiología , Estradiol/administración & dosificación , Sofocos/fisiopatología , Menopausia/fisiología , Ovariectomía , Animales , Regulación de la Temperatura Corporal/efectos de los fármacos , Implantes de Medicamentos , Estradiol/farmacología , Femenino , Modelos Animales , Distribución Aleatoria , Ovinos
10.
J Feline Med Surg ; 5(3): 183-9, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12765629

RESUMEN

The purpose of this study was to determine the effect of an alpha-glucosidase inhibitor (acarbose), combined with a low-carbohydrate diet on the treatment of naturally occurring diabetes mellitus in cats. Eighteen client-owned cats with naturally occurring diabetes mellitus were entered into the study. Dual-energy X-ray absorptiometry (DEXA) was performed prior to and 4 months after feeding the diet to determine total body composition, including lean body mass (LBM) and percent body fat. Each cat was fed a commercially available low-carbohydrate canned feline diet and received 12.5mg/cat acarbose orally every 12h with meals. All cats received subcutaneous insulin therapy except one cat in the study group that received glipizide (5mg BID PO). Monthly serum glucose and fructosamine concentrations were obtained, and were used to adjust insulin doses based on individual cat's requirements. Patients were later classified as responders (insulin was discontinued, n=11) and non-responders (continued to require insulin or glipizide, n=7). Responders were initially obese (>28% body fat) and non-responders had significantly less body fat than responders (<28% body fat). Serum fructosamine and glucose concentrations decreased significantly in both responder and non-responder groups over the course of 4 months of therapy. Better results were observed in responder cats, for which exogenous insulin therapy was discontinued, glycemic parameters improved, and body fat decreased. In non-responders, median insulin requirements decreased and glycemic parameters improved significantly, despite continued insulin dependence. The use of a low-carbohydrate diet with acarbose was an effective means of decreasing exogenous insulin dependence and improving glycemic control in a series of client-owned cats with naturally occurring diabetes mellitus.


Asunto(s)
Acarbosa/uso terapéutico , Enfermedades de los Gatos/dietoterapia , Enfermedades de los Gatos/tratamiento farmacológico , Diabetes Mellitus/veterinaria , Dieta para Diabéticos , Inhibidores de Glicósido Hidrolasas , Hipoglucemiantes/uso terapéutico , Absorciometría de Fotón/veterinaria , Acarbosa/administración & dosificación , Administración Oral , Animales , Glucemia , Composición Corporal , Gatos , Diabetes Mellitus/dietoterapia , Diabetes Mellitus/tratamiento farmacológico , Carbohidratos de la Dieta/administración & dosificación , Femenino , Fructosamina/sangre , Hipoglucemiantes/administración & dosificación , Masculino , Resultado del Tratamiento
11.
Vet J ; 163(3): 232-9, 2002 May.
Artículo en Inglés | MEDLINE | ID: mdl-12090765

RESUMEN

There is great interest in large animal models for studying different aspects of osteoporosis. Several laboratories around the world have used ovariectomized sheep as a model because of their ease of housing and handling, low expense compared to other large animals, availability and acceptance in society as a research animal. They have been used to study the response to new therapies for post-menopausal osteoporosis, low-magnitude mechanical stimulation, orthopedic implants in osteoporotic bone and bioactive ceramics to strengthen vertebral bodies. To produce severely osteopenic bone comparable to that seen in humans, a combination of estrogen deficiency following ovariectomy plus a calcium-wasting diet is currently being investigated.


Asunto(s)
Modelos Animales de Enfermedad , Osteoporosis , Ovinos , Animales , Enfermedades Óseas Metabólicas/fisiopatología , Calcio/deficiencia , Dieta , Humanos , Menopausia , Osteoporosis/fisiopatología , Ovariectomía/veterinaria , Columna Vertebral/patología
12.
Bone ; 30(3): 445-52, 2002 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11882457

RESUMEN

Departing from the premise that it is the large-amplitude signals inherent to intense functional activity that define bone morphology, we propose that it is the far lower magnitude, high-frequency mechanical signals that continually barrage the skeleton during longer term activities such as standing, which regulate skeletal architecture. To examine this hypothesis, we proposed that brief exposure to slight elevations in these endogenous mechanical signals would suffice to increase bone mass in those bones subject to the stimulus. This was tested by exposing the hind limbs of adult female sheep (n = 9) to 20 min/day of low-level (0.3g), high-frequency (30 Hz) mechanical signals, sufficient to induce a peak of approximately 5 microstrain (micro epsilon) in the tibia. Following euthanasia, peripheral quantitative computed tomography (pQCT) was used to segregate the cortical shell from the trabecular envelope of the proximal femur, revealing a 34.2% increase in bone density in the experimental animals as compared with controls (p = 0.01). Histomorphometric examination of the femur supported these density measurements, with bone volume per total volume increasing by 32% (p = 0.04). This density increase was achieved by two separate strategies: trabecular spacing decreased by 36.1% (p = 0.02), whereas trabecular number increased by 45.6% (p = 0.01), indicating the formation of cancellous bone de novo. There were no significant differences in the radii of animals subject to the stimulus, indicating that the adaptive response was local rather than systemic. The anabolic potential of the signal was evident only in trabecular bone, and there were no differences, as measured by any assay, in the cortical bone. These data suggest that subtle mechanical signals generated during predominant activities such as posture may be potent determinants of skeletal morphology. Given that these strain levels are three orders of magnitude below strains that can damage bone tissue, we believe that a noninvasive stimulus based on this sensitivity has potential for treating skeletal complications such as osteoporosis.


Asunto(s)
Huesos/fisiología , Animales , Densidad Ósea/fisiología , Estimulación Eléctrica/métodos , Femenino , Osteogénesis/fisiología , Presión/efectos adversos , Ovinos , Vibración/efectos adversos
13.
Am J Vet Res ; 62(8): 1234-9, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11497444

RESUMEN

OBJECTIVE: To evaluate changes in resting energy expenditure (REE) as well as protein and carbohydrate metabolism in dogs with osteosarcoma (OSA). ANIMALS: 15 weight-stable dogs with OSA that did not have other concurrent metabolic or endocrine illness and twelve 1-year-old sexually intact female Beagles (control dogs). PROCEDURES: Indirect calorimetry was performed on all dogs to determine REE and respiratory quotient (RQ). Stable isotope tracers (15N-glycine, 4.5 mg/kg of body weight, IV; 6,6-deuterium-glucose, 4.5 mg/kg, IV as a bolus, followed by continuous-rate infusion at 1.5 mg/kg/h for 3 hours) were used to determine rate of protein synthesis and glucose flux in all dogs. Dual-energy x-ray absorptiometry (DEXA) scans were performed to determine total body composition. RESULTS: Accounting for metabolic body size, REE in dogs with OSA was significantly higher before and after surgery, compared with REE of healthy control dogs. The RQ values did not differ significantly between groups. Dogs with OSA also had decreased rates of protein synthesis, increased urinary nitrogen loss, and increased glucose flux during the postoperative period. CONCLUSIONS AND CLINICAL RELEVANCE: Alterations in energy expenditure, protein synthesis, urinary nitrogen loss, and carbohydrate flux were evident in dogs with OSA, similar to results documented in humans with neoplasia. Changes were documented in REE as well as protein and carbohydrate metabolism in dogs with OSA. These changes were evident even in dogs that did not have clinical signs of cachexia.


Asunto(s)
Neoplasias Óseas/veterinaria , Enfermedades de los Perros/metabolismo , Osteosarcoma/veterinaria , Absorciometría de Fotón/veterinaria , Animales , Neoplasias Óseas/metabolismo , Calorimetría Indirecta/veterinaria , Perros , Metabolismo Energético/fisiología , Femenino , Glucosa/análisis , Glucosa/metabolismo , Glicina/sangre , Glicina/metabolismo , Glicina/orina , Masculino , Osteosarcoma/metabolismo
14.
Nature ; 412(6847): 603-4, 2001 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-11493908

RESUMEN

Although the skeleton's adaptability to load-bearing has been recognized for over a century, the specific mechanical components responsible for strengthening it have not been identified. Here we show that after mechanically stimulating the hindlimbs of adult sheep on a daily basis for a year with 20-minute bursts of very-low-magnitude, high-frequency vibration, the density of the spongy (trabecular) bone in the proximal femur is significantly increased (by 34.2%) compared to controls. As the strain levels generated by this treatment are three orders of magnitude below those that damage bone tissue, this anabolic, non-invasive stimulus may have potential for treating skeletal conditions such as osteoporosis.


Asunto(s)
Huesos/fisiología , Adaptación Fisiológica , Animales , Densidad Ósea , Huesos/anatomía & histología , Huesos/metabolismo , Femenino , Fémur , Miembro Posterior , Ovinos , Vibración , Soporte de Peso
15.
Biomed Sci Instrum ; 37: 263-8, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11347400

RESUMEN

Long-term biomechanical integrity of the surgical site is crucial to the outcome of rotator cuff repair. Usually after rotator-cuff surgery, the arm is immobilized for 6-12 weeks to minimize disruption at the healing site. Unfortunately, currently there is very little clinical data on the effects of immobilization after rotator cuff surgery. This study analyzed the effect of immobilization on rotator cuff healing by comparing the healing strength of the tendon in a bone trough using a sheep model. In sixteen (16) female adult sheep, the right infraspinatus tendons were reattached into a bone trough using a modified Mason-Allen suture pattern. After surgery, each sheep was randomly assigned into either an immobilized or non-immobilized treatment group. The immobilized group was fitted with a softball taped under the foot to restrict limb movement for 6 weeks. The non-immobilized treatment group was allowed to fully bear weight on the treated shoulder. At 26 weeks, the animals were sacrificed and the surgical shoulders were harvested and stored in a -30 degrees C freezer. Biomechanical testing was performed using a MTS 809 Axial/Torsional Servohydraulic System. Special cryo-grips were used to test the infraspinatus tendon-bone interface in anatomical alignment. All samples were preloaded with 10 +/- 5 N, and then force was measured during a crosshead displacement of 500 mm/min until failure. Force and displacement were acquired at 100 Hz and used to calculate load-to-failure and stiffness of the bone-tendon interface. The load-to-failure (N) and stiffness (N/cm) were determined for both treatment groups. For the non-immobilized group, the loads to failure and stiffness means were 2571.95 +/- 329.9 N and 2319.09 +/- 457.72 N/cm. The immobilized group means were 2954.42 +/- 473.52 N (load-to-failure) and 2579.13 +/- 383.51 N/cm (stiffness). A two-tailed two-samples unequal variance student t-test with significance set at 0.05, found no significant difference between the treatment groups for load-to-failure (p = 0.2174) and stiffness (p = 0.8286).


Asunto(s)
Inmovilización , Manguito de los Rotadores/cirugía , Técnicas de Sutura , Cicatrización de Heridas , Animales , Fenómenos Biomecánicos , Femenino , Manguito de los Rotadores/fisiopatología , Ovinos
17.
Eur Cell Mater ; 1: 66-81, 2001 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-14562261

RESUMEN

There is a great need to further characterise the available animal models for postmenopausal osteoporosis, for the understanding of the pathogenesis of the disease, investigation of new therapies (e.g. selective estrogen receptor modulators (SERMs)) and evaluation of prosthetic devices in osteoporotic bone. Animal models that have been used in the past include non-human primates, dogs, cats, rodents, rabbits, guinea pigs and minipigs, all of which have advantages and disadvantages. Sheep are a promising model for various reasons: they are docile, easy to handle and house, relatively inexpensive, available in large numbers, spontaneously ovulate, and the sheep's bones are large enough to evaluate orthopaedic implants. Most animal models have used females and osteoporosis in the male has been largely ignored. Recently, interest in development of appropriate prosthetic devices which would stimulate osseointegration into osteoporotic, appendicular, axial and mandibular bone has intensified. Augmentation of osteopenic lumbar vertebrae with bioactive ceramics (vertebroplasty) is another area that will require testing in the appropriate animal model. Using experimental animal models for the study of these different facets of osteoporosis minimizes some of the difficulties associated with studying the disease in humans, namely time and behavioral variability among test subjects. New experimental drug therapies and orthopaedic implants can potentially be tested on large numbers of animals subjected to a level of experimental control impossible in human clinical research.

18.
J Vet Pharmacol Ther ; 23(3): 175-9, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11110106

RESUMEN

BACKGROUND: Ovariectomized sheep are a useful model of postmenopausal osteoporosis and other postmenopausal conditions. Estrogen may have a protective effect on the coronary arteries in postmenopausal women. The effects of raloxifene, a selective estrogen receptor modulator, on coronary arteries in aged ovariectomized ewes was investigated. METHODS AND RESULTS: Forty eight aged ewes were randomly assigned to undergo sham surgery (Sham, n = 7), ovariectomy (OVX, n = 10), ovariectomy with estradiol supplementation (OVXE, n = 8), ovariectomy with raloxifene supplementation, 0.02 mg/kg per day (RAL1, n = 10), or ovariectomy with raloxifene supplementation, 0.10 mg/kg per day (RAL2, n = 13). Contrast coronary angiography was performed 6 months after intervention. Diameters of the right main and left anterior descending coronary arteries in the RAL1, RAL2 and Sham groups were not different from each other, but were significantly greater than the OVX and OVXE groups. Intracoronary nitroglycerin did not affect the relationships of the diameters in any group. There were no differences in vascular remodeling between the groups. CONCLUSIONS: The results indicate that raloxifene in this sheep model allows greater dilation of coronary arteries than estrogen. Raloxifene may provide a significant protective functional effect on coronary arteries in postmenopausal heart disease.


Asunto(s)
Vasos Coronarios/efectos de los fármacos , Ovariectomía , Clorhidrato de Raloxifeno/farmacología , Moduladores Selectivos de los Receptores de Estrógeno/farmacología , Vasodilatación/efectos de los fármacos , Animales , Colesterol/sangre , Angiografía Coronaria , Modelos Animales de Enfermedad , Estradiol/administración & dosificación , Estradiol/farmacología , Femenino , Inyecciones Subcutáneas , Nitroglicerina/farmacología , Clorhidrato de Raloxifeno/administración & dosificación , Moduladores Selectivos de los Receptores de Estrógeno/administración & dosificación , Ovinos , Vasodilatadores/farmacología
19.
Spine (Phila Pa 1976) ; 25(20): 2580-7, 2000 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-11034641

RESUMEN

STUDY DESIGN: A randomized experimental evaluation of direct current stimulation in a validated animal model with an experimental control group, using blinded radiographic, biomechanical, histologic, and statistical measures. OBJECTIVES: To evaluate the efficacy of the adjunctive use of direct current stimulation on the fusion rate and speed of healing of titanium interbody fusion cages packed with autograft in a sheep lumbar interbody fusion model. SUMMARY OF BACKGROUND DATA: Titanium lumbar interbody spinal fusion cages have been reported to be 90% effective for single-level lumbar interbody fusion. However, fusion rates are reported to be between 70% and 80% in patients with multilevel fusions or with risk factors such as obesity, tobacco use, or metabolic disorders. The authors hypothesized that direct current stimulation would increase the fusion rate of titanium interbody fusion cages packed with autograft in a sheep lumbar interbody fusion model. METHODS: Twenty-two sheep underwent lumbar discectomy and fusion at L4-L5 with an 11- x 20-mm Bagby and Kuslich (BAK) cage packed with autograft. Seven sheep received a BAK cage and no current. Seven sheep had a cage and a 40-microA current applied with a direct current stimulator. Eight sheep had a BAK cage and a 100-microA current applied. All sheep were killed 4 months after surgery. The efficacy of electrical stimulation in promoting interbody fusion was assessed by performing radiographic, biomechanical, and histologic analyses in a blinded fashion. RESULTS: The histologic fusion rate increased as the direct current dose increased from 0 microA to 40 microA to 100 microA (P < 0.009). Histologically, all animals in the 100-microA group had fusions in both the right and left sides of the cage. Direct current stimulation had a significant effect on increasing the stiffness of the treated motion segment in right lateral bending (P < 0.120), left lateral bending (P < 0.017), right axial rotation (P < 0.004), left axial rotation (P < 0.073), extension (P < 0.078), and flexion (P < 0.029) over nonstimulated levels. CONCLUSION: Direct current stimulation increased the histologic and biomechanical fusion rate and the speed of healing of lumbar interbody spinal fusion cages in an ovine model at 4 months.


Asunto(s)
Cámaras de Difusión de Cultivos/instrumentación , Terapia por Estimulación Eléctrica/métodos , Fijadores Internos/normas , Fusión Vertebral/instrumentación , Fusión Vertebral/métodos , Columna Vertebral/cirugía , Animales , Fenómenos Biomecánicos , Cámaras de Difusión de Cultivos/métodos , Modelos Animales de Enfermedad , Terapia por Estimulación Eléctrica/instrumentación , Radiografía , Rango del Movimiento Articular/fisiología , Ovinos/cirugía , Columna Vertebral/citología , Columna Vertebral/diagnóstico por imagen , Trasplante Autólogo/instrumentación , Trasplante Autólogo/métodos , Resultado del Tratamiento
20.
J Zoo Wildl Med ; 31(2): 190-5, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10982131

RESUMEN

Figure-of-eight wing bandaging is widely used to treat wing injuries, to immobilize wings before and after fracture repair, and during transient wing paralysis. However, prolonged bandaging can lead to bone loss and to contractures and reduced range of joint motion. Studies evaluating the efficacy of therapeutic ultrasound to reverse and prevent bandaging-associated contractures in pigeons (Columba livia) showed a significant increase in elbow and carpal extension after 10 twice weekly ultrasound treatments when started either 4 or 11 days after bandage placement. In addition, after 42 days of wing bandaging, three ultrasound treatments stimulated a faster reversal of carpal wing rotation loss than removal of the bandage over the 10-day treatment period. Finally, bone loss in response to 28 days of bandaging was significant, progressed at 2.8% per week, and was not affected by ultrasound treatment twice weekly during this period. Therefore, therapeutic ultrasound prevented and reversed loss of wing extension associated with figure-of-eight bandaging but did not lessen the disuse osteoporosis created by bandaging in these birds.


Asunto(s)
Enfermedades de las Aves/terapia , Columbidae , Contractura/veterinaria , Curación de Fractura/fisiología , Osteoporosis/veterinaria , Terapia por Ultrasonido/veterinaria , Absorciometría de Fotón/veterinaria , Animales , Vendajes/efectos adversos , Vendajes/veterinaria , Enfermedades de las Aves/prevención & control , Densidad Ósea/fisiología , Columbidae/lesiones , Contractura/etiología , Contractura/terapia , Femenino , Fracturas Óseas/terapia , Fracturas Óseas/veterinaria , Masculino , Osteoporosis/etiología , Osteoporosis/terapia , Alas de Animales/lesiones
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