Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 43
Filtrar
1.
Reprod Fertil Dev ; 35(11): 563-574, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37290449

RESUMEN

CONTEXT: Melatonin influences female reproduction, but expression of the melatonin system has not been characterised in the ovine uterus. AIMS: We aimed to determine whether synthesising enzymes (arylalkylamine N-acetyltransferase (AANAT) and N-acetylserotonin-O-methyltransferase (ASMT)), melatonin receptors 1 and 2 (MT1 and MT2), and catabolising enzymes (myeloperoxidase (MPO) and indoleamine 2,3-dioxygenase 1 and 2 (IDO1 and 2)), are expressed in the ovine uterus, and if they are influenced by the oestrous cycle (Experiment 1) or by undernutrition (Experiment 2). METHODS: In Experiment 1, gene and protein expression was determined in sheep endometrium samples collected on days 0 (oestrus), 5, 10 and 14 of the oestrous cycle. In Experiment 2, we studied uterine samples from ewes fed either 1.5 or 0.5times their maintenance requirements. KEY RESULTS: We have demonstrated the expression of AANAT and ASMT in the endometrium of sheep. AANAT and ASMT transcripts, and AANAT protein were more elevated at day 10, then decreased to day 14. A similar pattern was observed for MT2 , IDO1 , and MPO mRNA, which suggests that the endometrial melatonin system might be influenced by ovarian steroid hormones. Undernutrition increased AANAT mRNA expression, but seemed to decrease its protein expression, and increased MT2 and IDO2 transcripts, whereas ASMT expression was unaffected. CONCLUSIONS: The melatonin system is expressed in the ovine uterus and is affected by oestrous cycle and undernutrition. IMPLICATIONS: The results help explain the adverse effects of undernutrition on reproduction in sheep, and the success of exogenous melatonin treatments in improving reproductive outcomes.


Asunto(s)
Melatonina , Animales , Ovinos/genética , Femenino , Melatonina/metabolismo , Útero/metabolismo , Endometrio/metabolismo , ARN Mensajero/metabolismo , N-Acetiltransferasa de Arilalquilamina/genética , N-Acetiltransferasa de Arilalquilamina/metabolismo , Acetilserotonina O-Metiltransferasa/genética , Acetilserotonina O-Metiltransferasa/metabolismo
2.
Theriogenology ; 162: 74-83, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33450716

RESUMEN

The objective of this study was to evaluate the effect of the administration of estradiol cypionate (ECP) at the end of an estradiol and progesterone-based protocol for fixed time artificial insemination (FTAI) on ovarian response and uterine function in postpartum anestrous beef cows. Multiparous suckled cows were randomly assigned to receive ECP at doses of 0 (control, n = 15), 0.5 (n = 15) or 1.0 mg (n = 15) im at the time of progesterone intravaginal insert removal. Serum 17ß-estradiol concentrations at 24 h after insert removal were greater (P < 0.05) in both ECP treatments than in controls. No differences in estradiol were found between 0.5 mg and control cows (P > 0.1) from 48 h after insert removal until ovulation, although greater (P < 0.05) concentrations were maintained until ovulation in 1.0 mg ECP treated cows. Maximum 17ß-estradiol concentration attained in each female was greater as ECP dose was greater (10.4 ± 0.4, 11.8 ± 0.5 and 13.5 ± 0.7, for control, 0.5 and 1.0 mg ECP treated cows, respectively; P < 005). Proportion of cows that ovulated tended to be greater (P = 0.06) in ECP treated than in control cows. Ovulation occurred earlier and the size of the ovulatory follicle was smaller (P < 0.05) for 1.0 mg but not for 0.5 mg (P > 0.1) when compared with control cows. After ovulation (Day 13 and 14), serum progesterone concentrations were greater (P < 0.05) in 0.5 and 1.0 mg ECP than control cows. Uterine environment on Day 6 after ovulation was affected by treatment; transcript expression of three of nine evaluated genes (i.e., estrogen, IGF-1 and insulin receptors genes) were upregulated (P < 0.05) after ECP treatment. In conclusion, ECP administration at progesterone insert removal in anestrous cows i) induces greater serum estradiol concentrations and tended to induce greater ovulation rate, ii) acts in a dose-dependent manner, as ECP dose increases ovulation occurs earlier and the size of the ovulatory follicle is smaller, iii) improves postovulatory luteal function and affects uterine gene expression. Altogether, this information contributes with the understanding of the effect of preovulatory estradiol exposure on ovulation and postovulatory ovarian and uterine function in anestrous beef cows.


Asunto(s)
Inseminación Artificial , Progesterona , Animales , Bovinos , Ensayos Clínicos Veterinarios como Asunto , Estradiol/análogos & derivados , Sincronización del Estro , Femenino , Inseminación Artificial/veterinaria , Ovulación
4.
Theriogenology ; 151: 16-27, 2020 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-32251936

RESUMEN

The objective of the present study was to evaluate the effect of equine chorionic gonadotropin (eCG) administration associated to different proestrus lengths for Fixed-time AI (FTAI) in beef heifers. In Experiment 1, pre-pubertal heifers (n = 46) received a 6-day estradiol/progesterone-based treatment (J-Synch protocol), and were then allocated into four experimental groups in a 2 × 2 factorial design, to receive or not receive eCG (300 IU) at the time of intravaginal progesterone device removal, and to receive GnRH at 48 h or 72 h after device removal (to induce shortened and prolonged proestrus length, respectively). Endometrial samples were obtained 6 d after ovulation from the cranial portion of the uterine horn. The eCG administration induced greater serum estradiol-17ß concentrations before ovulation (P < 0.05) and greater proportion of heifers bearing a competent corpus luteum after ovulation (P = 0.054). Delaying GnRH administration from 48 h to 72 h induced a longer interval from device removal to ovulation (i.e., prolonged proestrus; P < 0.05), larger diameter of the ovulatory follicle, and greater progesterone concentrations on Day 10-11 after ovulation. Heifers in eCG + GnRH72h group had more uterine receptors in luminal epithelium than those in eCG + GnRH48h group (PR and ERα), and than those in No eCG + GnRH72h group (PR) (P < 0.05). No effect of eCG or GnRH treatments was found in endometrial gene expression of progesterone and estrogen receptors. In Experiment 2, a total of 2,598 heifers received the J-Synch protocol associated or not with eCG administration at device removal, followed by FTAI/GnRH at 60 or 72 h after device removal (i.e., prolonged proestrus protocol). Heifers that received eCG had greater P/AI than those not receiving eCG (P < 0.05) and there was an interaction between eCG treatment and time of FTAI. The lowest P/AI was found in those heifers that received FTAI/GnRH at 72 h without eCG treatment at device removal (P < 0.05), and no differences were found between the other experimental groups. In conclusion, prolonging the length of proestrus in J-Synch protocol improves ovulatory follicular diameter and luteal function; and the administration of eCG at device removal improves preovulatory estradiol concentrations and luteal function. Finally, P/AI was enhanced by eCG treatment and the improvement was more evident when FTAI/GnRH was performed at 72 h after device removal.


Asunto(s)
Bovinos , Gonadotropina Coriónica/farmacología , Ovulación/efectos de los fármacos , Útero/efectos de los fármacos , Animales , Sincronización del Estro/métodos , Femenino , Inseminación Artificial/veterinaria , Folículo Ovárico/efectos de los fármacos , Inducción de la Ovulación/veterinaria , Embarazo , Índice de Embarazo , Útero/fisiología
5.
Theriogenology ; 151: 7-15, 2020 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-32251939

RESUMEN

The objective of this study was to evaluate the local effect of the corpus luteum (CL) on ipsilateral oviduct-uterus functionality and early embryo development in ewes. A total of 499 embryos were transferred on Day 1 after in vitro fertilization into the ipsilateral (n = 250) and contralateral oviducts (n = 249) of 13 ewes on Day 1 after ovulation (18-20 embryos per oviduct). On Day 6, their reproductive tracts were collected and their uterine horns were flushed for embryo recovery. More recovered embryos, a higher proportion of blastocysts, and more viable embryos were collected when the embryos were transferred into the ipsilateral oviducts (P < 0.05). In addition, almost five times higher P4 concentrations and significantly lower E2 concentrations, with higher P4:E2 ratio, were found in the ipsilateral than contralateral oviductal tissue (P < 0.05). Furthermore, a higher concentration of adiponectin was found in the ipsilateral uterine tissue macerates than in the contralateral side to the CL. The ipsilateral oviductal tissue had a lower expression of PGR and IGFBP5, but the transcript expression of ADIPOR1 was higher in the ipsilateral oviductal tissue. In the uterus, the mRNA expression of ESR1, IGFBP3, IGFBP5, and LEPR was higher or tended to be higher in the ipsilateral than contralateral uterine tissue. Uterine flushing fluid collected from the ipsilateral uterine horn had lower insulin concentrations than the contralateral horn, while no differences were found in the P4 and E2 concentrations. In conclusion, on Day 6 post-ovulation, P4 was elevated in the ipsilateral oviductal tissue, embryo development was advanced, and differential gene expression of PGR, ESR1, IGFBP3, IGFBP5, LEPR, and ADIPOR1 in the oviductal or uterine tissue was found between the ipsilateral and contralateral side. This study demonstrates local regulation of the ovary on the ipsilateral oviduct/uterine horn in the ewe.


Asunto(s)
Cuerpo Lúteo/fisiología , Embrión de Mamíferos , Desarrollo Embrionario , Trompas Uterinas/fisiología , Ovinos/fisiología , Animales , Femenino
6.
Reprod Fertil Dev ; 30(11): 1541-1552, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29778102

RESUMEN

The aim of the present study was to investigate the effects of a strategy for extending pro-oestrus (the interval between luteolysis and ovulation) in an oestrus synchronisation protocol (named J-Synch) in beef heifers on follicular growth, sexual steroid concentrations, the oestrogen receptor ERα and progesterone receptors (PR) in the uterus, insulin-like growth factor (IGF) 1 and pregnancy rates. In Experiment 1, heifers treated with the new J-Synch protocol had a longer pro-oestrus period than those treated with the conventional protocol (mean (±s.e.m.) 93.7±12.9 vs 65.0±13.7h respectively; P<0.05). The rate of dominant follicle growth from the time of progesterone device removal to ovulation was greater in heifers in the J-Synch than conventional group (P<0.05). Luteal area and serum progesterone concentrations were greater in the J-Synch Group (P<0.05) for the 12 days after ovulation. Progesterone receptor (PGR) staining on Day 6 after ovulation in the uterine stroma was lower in the J-Synch than conventional group (P<0.05), and the expression of PR gene (PGR) and IGF1 gene tended to be lower in J-Synch-treated heifers (P<0.1). In Experiment 2 (n=2349), the pregnancy rate 30-35 days after fixed-time AI (FTAI) was greater for heifers in the J-Synch than conventional group (56.1% vs 50.7% respectively). In conclusion, our strategy for extending pro-oestrus (i.e. the J-Synch protocol) significantly improves pregnancy establishment in beef heifers. This improvement was related to an increased rate of growth of the dominant ovulatory follicle, greater progesterone concentrations during the ensuing luteal phase and different uterine patterns of PGR and IGF1, which may have favoured embryo development and pregnancy establishment.


Asunto(s)
Estradiol/análogos & derivados , Sincronización del Estro/fisiología , Ovario/fisiología , Proestro/fisiología , Progesterona/administración & dosificación , Útero/fisiología , Animales , Bovinos , Estradiol/administración & dosificación , Estradiol/sangre , Sincronización del Estro/efectos de los fármacos , Femenino , Folículo Ovárico/diagnóstico por imagen , Folículo Ovárico/efectos de los fármacos , Ovario/diagnóstico por imagen , Ovario/efectos de los fármacos , Embarazo , Proestro/efectos de los fármacos , Progesterona/sangre , Receptores de Estrógenos/metabolismo , Receptores de Progesterona/metabolismo , Útero/diagnóstico por imagen , Útero/efectos de los fármacos
7.
Anim Reprod Sci ; 195: 321-328, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31262405

RESUMEN

This study evaluated the effect of progesterone priming during follicular growth on oocyte competence to undergo oocyte cleavage and embryo development in sheep. Two experiments were performed on a total of 195 females that either received or did not receive a progesterone treatment (CIDR-type device) during the first follicular wave, beginning soon after ovulation (i.e., Day 0 of the experiment). On Day 3, the follicular population and oocyte quality (Experiment 1 and 2) and the competence of oocytes for cleavage and embryo development (Experiment 2) were evaluated after laparoscopic ovum pickup (LOPU) and in vitro fertilization. In Experiment 1, in a 2 × 2 factorial study the progesterone priming treatment (treated or not) was or was not associated with a single dose of FSH in a slow-release hyaluronic acid preparation given on Day 0. The follicular population on Day 3 and the number and morphology of recovered cumulus oocyte complexes (COCs) were not affected by the progesterone treatment (P = NS) but were improved by the FSH administration (P <  0.05). An interaction between both treatments was observed (P <  0.05), with more desirable outcome with the females that received both the progesterone and the FSH treatments. In Experiment 2, half of the females received the exogenous progesterone priming, and all females received FSH on Day 0. After follicular aspiration on Day 3, the cleavage rate and the embryo development rate following in vitro fertilization and culture were greater in those females that received the progesterone treatment (P <  0.05). In conclusion, these studies provide evidence that progesterone treatment during follicular growth affects oocyte competence, with the greater progesterone concentrations enhancing the oocyte's capacity to undergo cleavage and embryo development.


Asunto(s)
Desarrollo Embrionario , Fertilización In Vitro/veterinaria , Técnicas de Maduración In Vitro de los Oocitos/veterinaria , Oocitos/citología , Oogénesis , Folículo Ovárico/crecimiento & desarrollo , Progesterona/farmacología , Animales , Femenino , Hormona Folículo Estimulante/metabolismo , Oocitos/efectos de los fármacos , Folículo Ovárico/efectos de los fármacos , Progesterona/sangre , Ovinos
8.
Eur J Orthop Surg Traumatol ; 27(3): 295-299, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28120098

RESUMEN

The treatment of the four-part fractures of the proximal humerus remains a therapeutic challenge. The decision-making is based on preoperative criteria concerning the displacement of the fracture, the stability of the fracture and the risk of avascular necrosis of the humeral head. The aim of this study was to analyse the inter- and intra-observer reproducibility of those criteria previously described by Hertel. Three observers analysed three times 20 radiologic files comprising 2D X-rays, 2D CT scan and 3D reconstructions for the intra-observer study, and an expert committee was used to assess the inter-observer reproducibility. The Kappa coefficient was used to measure agreement. The Kappa coefficient founded poor to moderate agreement for the majority of the criteria after the 2D X-ray analysis. This coefficient was improved with the use of 2D CT scan and 3D reconstructions, in particular for the medial hinge assessment, the humeral head fracture and the metaphyseal extension. The reproducibility of the criteria described by Hertel on 2D X-rays is at least moderate. Reproducibility could be considerably improved by associating 2D scans and 3D reconstruction, in particular for the criteria related to prognosis for the vascularisation of the humeral head.


Asunto(s)
Cabeza Humeral/irrigación sanguínea , Cabeza Humeral/diagnóstico por imagen , Fracturas del Hombro/diagnóstico por imagen , Toma de Decisiones Clínicas , Humanos , Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Variaciones Dependientes del Observador , Reproducibilidad de los Resultados , Tomografía Computarizada por Rayos X
9.
Orthop Traumatol Surg Res ; 102(7): 867-872, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-27717747

RESUMEN

INTRODUCTION: The use of the semitendinosus tendon alone for anterior cruciate ligament reconstruction keeps the gracilis muscle intact and decreases anterior pain in comparison with the use of the patellar tendon. Recently, Lubowitz described a new all-inside technique with an ST4 tendon fixed with a cortical button in both femoral and tibial sides. We hypothesized that this type of graft with cortical button fixation provides well-controlled residual anterior tibial translation (<3mm). The aim of this study was to assess the results obtained with this technique in terms of laxity and IKDC score at more than 1 year of follow-up. MATERIAL AND METHODS: We performed a prospective single-center study to evaluate the results with this procedure with at least 1 year of follow-up. The primary endpoint was the objective IKDC score and side-to-side anterior tibial translation difference. The secondary endpoint was the subjective assessment using the subjective IKDC and Lysholm scores. Tunnel positioning was assessed using the Aglietti criteria. RESULTS: Thirty-five patients were included and reviewed with a mean follow-up of 19.7 months. Sixty-three percent of the patients were male and the mean age at the procedure was 28 years. The IKDC score was A or B in 43% of the patients and C or D in 57%; 54% of the patients had a residual side-to-side anterior tibial translation difference less than 3mm and 29% presented significant pivot shift (grade C or D). Five patients underwent revision surgery, including one for rupture of the ACL reconstruction. The meniscal status did not influence postoperative laxity and the IKDC grade. DISCUSSION: Our hypothesis was not verified and the postoperative stability of the knee was insufficient. Postoperative side-to-side anterior tibial translation difference remained greater than 3mm for 16 patients and the analysis seems to indicate that the distal cortical fixation of the graft with an adjusted loop is insufficient. LEVEL OF EVIDENCE: Prospective study - Level IV.


Asunto(s)
Lesiones del Ligamento Cruzado Anterior/cirugía , Reconstrucción del Ligamento Cruzado Anterior/métodos , Tendones Isquiotibiales/trasplante , Inestabilidad de la Articulación/etiología , Complicaciones Posoperatorias , Adulto , Femenino , Fémur/cirugía , Estudios de Seguimiento , Indicadores de Salud , Humanos , Inestabilidad de la Articulación/diagnóstico , Masculino , Complicaciones Posoperatorias/diagnóstico , Estudios Prospectivos , Tibia/cirugía , Resultado del Tratamiento , Adulto Joven
10.
Theriogenology ; 86(6): 1557-1565, 2016 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-27325575

RESUMEN

The objective of this study was to investigate the gene expression of progesterone and estrogen receptor α (PR, ERα), insulin-like growth factor (IGF) 1, IGF-2, their receptor (IGFR1), IGF-binding proteins (BP) 1 to 6, insulin receptor, adiponectin receptors (AdipoR1/2), cyclooxygenase 2 (PTGS2), mucin 1 and to localize PR, ERα, IGF-1, IGFR1, PTGS2, and proliferating cellular nuclear antigen (PCNA) in the endometrium of pregnant (Day 19) Suffolk and Cheviot ewes carrying Suffolk and Cheviot embryos transferred within and reciprocally between breeds. Gene expression was determined by real-time quantitative polymerase chain reaction (RT-qPCR), and antigen determination was measured by immunohistochemistry in the luminal epithelium (LE), superficial and deep glands (SG, DG, respectively) and superficial and deep stroma. Gene expression of PR, IGF-1, IGFBP2, and IGFBP5 was higher in Suffolk than that in Cheviot ewes (P < 0.05). Greater abundance of IGF-2 and IGBP3 expression was found in Cheviot ewes carrying Cheviot embryos than Cheviot ewes carrying Suffolk embryos (P < 0.05). No staining for PR and ERα was observed in the LE, very scarce staining in SG and DG, whereas positive staining was observed in both superficial and deep stroma. No differences were found for PR staining, but Cheviot ewes had higher ERα staining intensity than Suffolk ewes (P < 0.05). Positive staining for IGF-1 was observed in all cell types except DG, and staining of IGFR1 was observed in all cell types. No differences among groups in staining were found for IGF-1 or IGFR1 in any cell type. Positive staining of PTGS2 was observed in LE and SG in all groups. An interaction between ewe and embryo breed affected PTGS2 staining (P < 0.05), whereby Cheviot ewes carrying Suffolk embryos had a lower PTGS2 staining than Suffolk ewes carrying Suffolk embryos. Positive staining of PCNA was found in LE and SG. Suffolk ewes carrying Suffolk embryos showed lower PCNA immunostaining than Cheviot ewes carrying Suffolk embryos (P < 0.05), whereas no differences were observed in ewes carrying Cheviot embryos. This study showed that gestation-related protein expression in the endometrium of Suffolk and Cheviot ewes is affected by both ewe and embryo breed at Day 19 of pregnancy.


Asunto(s)
Transferencia de Embrión/veterinaria , Endometrio/química , Endometrio/metabolismo , Expresión Génica , Ovinos/genética , Animales , Ciclooxigenasa 2/análisis , Ciclooxigenasa 2/genética , Desarrollo Embrionario/genética , Receptor alfa de Estrógeno/análisis , Receptor alfa de Estrógeno/genética , Femenino , Edad Gestacional , Inmunohistoquímica , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/genética , Factor I del Crecimiento Similar a la Insulina/análisis , Factor II del Crecimiento Similar a la Insulina/genética , Mucina-1/genética , Embarazo , Antígeno Nuclear de Célula en Proliferación/análisis , Receptor IGF Tipo 1/análisis , Receptor IGF Tipo 1/genética , Receptor de Insulina/genética , Receptores de Adiponectina/genética , Receptores de Progesterona/análisis , Receptores de Progesterona/genética , Especificidad de la Especie
11.
J Anim Physiol Anim Nutr (Berl) ; 99(4): 710-8, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25319346

RESUMEN

This study investigated whether a 22-day period of undernutrition (half maintenance) could affect maternal endocrine responses and liver gene expression during early pregnancy (day 7). Thirty-five ewes were fed 1.5 (n = 15) or 0.5 (n = 20) their maintenance requirements and slaughtered on day 7 of the oestrus cycle or pregnancy (oestrus = day 0). Insulin, IGF, leptin and non-esterified fatty acids (NEFA) were determined on days -14, 0 and 7. Transcripts of the IGF family and adipokines receptors were determined in the liver by real-time RT-PCR. Underfed animals presented lower body weight and body condition, greater plasma concentration of NEFA, and lower plasma concentrations of leptin, insulin and IGF1 compared to adequately fed animals. Underfed ewes presented greater hepatic expression of IGFBP2 than well-fed ewes, but tended to have lesser expression of IGFBP5. While no effect of undernutrition on IGFBP4 and ADIPOR2 mRNA expressions was observed, they were increased by pregnancy in underfed animals. This study shows that undernutrition modifies endocrine profiles and hepatic gene expression of IGFBP2 and 5. The pregnancy status increased hepatic gene expression of IGFBP4 and ADIPOR2 mRNA in undernourished ewes.


Asunto(s)
Privación de Alimentos , Regulación de la Expresión Génica/fisiología , Hígado/metabolismo , Ovinos/metabolismo , Alimentación Animal , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Dieta/veterinaria , Ciclo Estral , Ácidos Grasos no Esterificados/sangre , Femenino , Insulina/sangre , Factor I del Crecimiento Similar a la Insulina/metabolismo , Leptina/sangre , Datos de Secuencia Molecular , Embarazo , ARN Mensajero , Ovinos/sangre
12.
Biomed Mater Eng ; 24(1 Suppl): 63-73, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24928919

RESUMEN

BACKGROUND: To favor regeneration following critical bone defect, a combination of autologous bone graft and biomaterials is currently used. Major drawbacks of such techniques remain the availability of the autologous material and the second surgical site, inducing pain and morbidity. OBJECTIVE: Our aim was to investigate the biocompatibility in vitro of three dimensions hybrid biodegradable scaffolds combining osteoconductive properties of hydroxyapatite and anti-inflammatory properties of chitosan. METHODS: Hybrid scaffolds were characterized by microscopic observations, equilibrium swelling ratio and overtime weight loss measurements. In vitro studies were performed using primary human bone cells cultured for 7, 14 and 21 days. Cell viability, proliferation, morphology and differentiation through alkaline phosphatase (ALP) activity measurement were assessed. RESULTS: Characterization of our scaffolds demonstrated porous, hydrophilic and biodegradable characteristics. In vitro studies showed that these scaffolds have induced slight decrease in cell death and proliferation comparing to the culture plastic substrate control condition, as well as increased short term osteoinductive properties. CONCLUSIONS: In this study, we have provided evidence that our hybrid hydroxyapatite/chitosan scaffolds could be suitable for bone filling.


Asunto(s)
Huesos/química , Quitosano/química , Durapatita/química , Ingeniería de Tejidos/métodos , Andamios del Tejido/química , Fosfatasa Alcalina/metabolismo , Materiales Biocompatibles/química , Biodegradación Ambiental , Diferenciación Celular , Proliferación Celular , Supervivencia Celular , Células Cultivadas , Humanos , L-Lactato Deshidrogenasa/metabolismo , Microscopía Electrónica de Rastreo
13.
Orthop Traumatol Surg Res ; 100(4): 385-8, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24751460

RESUMEN

BACKGROUND: Anterior cervical fusion is widely used to treat spinal injuries. Radiological evidence of disc abnormalities may develop on either side of the fused segment, raising concern about the potential for inducing adjacent-segment disease. Here, we report the long-term clinical, functional, and radiological outcomes after anterior cervical fusion. HYPOTHESIS: Anterior cervical fusion influences the development of adjacent-segment disease. MATERIALS AND METHODS: In a retrospective study, 15 patients aged 17 to 50 years were re-evaluated more than 5 years after anterior spinal fusion to treat post-traumatic cervical-spine instability. We used the Neck Disability Index (NDI) to assess function. Static and dynamic radiographs of the cervical spine were obtained. RESULTS: NDI values indicated good clinical and functional outcomes, and fusion was achieved consistently. Adjacent-segment disease was a consistent finding at last follow-up but induced no neurological manifestations. Complete fusion of a level adjacent to the treated level was noted in 2 patients. Revision surgery for adjacent-segment disease was not required in any patient. CONCLUSION: The causative factors of adjacent-segment disease are controversial. Disc degeneration is a normal manifestation of the ageing process. Nevertheless, disc disease is more prevalent at levels adjacent to interbody fusion than in the normal population, suggesting accelerated disc degeneration due to increased loading of the adjacent levels. Furthermore, lesions that are missed during the pre-operative work-up may play a role, as the available investigations do not always have high negative predictive values. LEVEL OF EVIDENCE: Level IV, retrospective study.


Asunto(s)
Vértebras Cervicales/diagnóstico por imagen , Degeneración del Disco Intervertebral/diagnóstico por imagen , Inestabilidad de la Articulación/cirugía , Fusión Vertebral/efectos adversos , Traumatismos Vertebrales/cirugía , Adolescente , Adulto , Vértebras Cervicales/lesiones , Femenino , Humanos , Degeneración del Disco Intervertebral/etiología , Inestabilidad de la Articulación/diagnóstico , Inestabilidad de la Articulación/diagnóstico por imagen , Inestabilidad de la Articulación/etiología , Masculino , Persona de Mediana Edad , Radiografía , Estudios Retrospectivos , Traumatismos Vertebrales/complicaciones , Traumatismos Vertebrales/diagnóstico por imagen , Adulto Joven
14.
Artículo en Inglés | MEDLINE | ID: mdl-23964349

RESUMEN

The egcSEs comprise five genetically linked staphylococcal enterotoxins, SEG, SEI, SElM, SElN, and SElO and two pseudotoxins which constitute an operon present in up to 80% of Staphylococcus aureus isolates. A preparation containing these proteins was recently used to treat advanced lung cancer with pleural effusion. We investigated the hypothesis that egcSEs induce nitrous oxide (NO) and associated cytokine production and that these agents may be involved in tumoricidal effects against a broad panel of clinically relevant human tumor cells. Preliminary studies showed that egcSEs and SEA activated T cells (range: 11-25%) in a concentration dependent manner. Peripheral blood mononuclear cells (PBMCs) stimulated with equimolar quantities of egcSEs expressed NO synthase and generated robust levels of nitrite (range: 200-250 µM), a breakdown product of NO; this reaction was inhibited by NG-monomethyl-L-arginine (L-NMMA) (0.3 mM), an NO synthase antagonist. Cell free supernatants (CSFs) of all egcSE-stimulated PBMCs were also equally effective in inducing concentration dependent tumor cell apoptosis in a broad panel of human tumor cells. The latter effect was due in part to the generation of NO and TNF-α since it was significantly abolished by L-NMMA, anti-TNF-α antibodies, respectively, and a combination thereof. A hierarchy of tumor cell sensitivity to these CFSs was as follows: lung carcinoma > osteogenic sarcoma > melanoma > breast carcinoma >neuroblastoma. Notably, SEG induced robust activation of NO/TNFα-dependent tumor cell apoptosis comparable to the other egcSEs and SEA despite TNF-α and IFN-γ levels that were 2 and 8 fold lower, respectively, than the other egcSEs and SEA. Thus, egcSEs produced by S. aureus induce NO synthase and the increased NO formation together with TNF-α appear to contribute to egcSE-mediated apoptosis against a broad panel of human tumor cells.


Asunto(s)
Apoptosis , Toxinas Bacterianas/toxicidad , Citocinas/metabolismo , Enterotoxinas/toxicidad , Óxido Nitroso/metabolismo , Staphylococcus aureus/metabolismo , Toxinas Bacterianas/inmunología , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Enterotoxinas/inmunología , Humanos , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/metabolismo , Familia de Multigenes
15.
Nature ; 451(7178): 541-4, 2008 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-18235494

RESUMEN

Observations of distant supernovae indicate that the Universe is now in a phase of accelerated expansion the physical cause of which is a mystery. Formally, this requires the inclusion of a term acting as a negative pressure in the equations of cosmic expansion, accounting for about 75 per cent of the total energy density in the Universe. The simplest option for this 'dark energy' corresponds to a 'cosmological constant', perhaps related to the quantum vacuum energy. Physically viable alternatives invoke either the presence of a scalar field with an evolving equation of state, or extensions of general relativity involving higher-order curvature terms or extra dimensions. Although they produce similar expansion rates, different models predict measurable differences in the growth rate of large-scale structure with cosmic time. A fingerprint of this growth is provided by coherent galaxy motions, which introduce a radial anisotropy in the clustering pattern reconstructed by galaxy redshift surveys. Here we report a measurement of this effect at a redshift of 0.8. Using a new survey of more than 10,000 faint galaxies, we measure the anisotropy parameter beta = 0.70 +/- 0.26, which corresponds to a growth rate of structure at that time of f = 0.91 +/- 0.36. This is consistent with the standard cosmological-constant model with low matter density and flat geometry, although the error bars are still too large to distinguish among alternative origins for the accelerated expansion. The correct origin could be determined with a further factor-of-ten increase in the sampled volume at similar redshift.

17.
J Control Release ; 115(3): 298-306, 2006 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-17045358

RESUMEN

The objective of the present study was to investigate and quantify the effects of ibuprofen, chlorpheniramine maleate and metoprolol tartrate on the thermal, mechanical and diffusional properties of polyacrylate-based films. Thin drug-containing films were prepared from organic Eudragit RS solutions and physicochemically characterized with respect to their glass transition temperature, mechanical properties and drug release kinetics in phosphate buffer pH 7.4. The apparent diffusion coefficient of the drug within the polymeric systems was determined by fitting an adequate solution of Fick's second law of diffusion to the experimentally determined release profiles. Importantly, the glass transition temperature of the films significantly decreased with increasing initial drug content, whereas the film flexibility and drug release rate increased. This clearly indicates that the three drugs act as efficient plasticizers for Eudragit RS. Interestingly, the mathematical analysis revealed that drug release was primarily controlled by diffusion. An increase in the initial drug content resulted in increased drug diffusivities and, thus, accelerated (absolute and relative) drug release rates. Importantly, quantitative relationships could be established between the drug diffusivity and the initial drug content. Based on this knowledge, the effects of the films' composition and thickness on the resulting drug release kinetics (also from coated solid dosage forms) can be predicted in a quantitative way.


Asunto(s)
Portadores de Fármacos , Plastificantes/química , Ácidos Polimetacrílicos/química , Química Farmacéutica , Clorfeniramina/química , Preparaciones de Acción Retardada , Difusión , Ibuprofeno/química , Cinética , Metoprolol/química , Modelos Químicos , Solubilidad , Resistencia a la Tracción , Temperatura de Transición
18.
J Eur Acad Dermatol Venereol ; 19(6): 737-9, 2005 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-16268882

RESUMEN

BACKGROUND: Surgery is the first treatment of a pigmented skin lesion when a melanoma is suspected. This excision is most of the time realized by the dermatologist as well as the second time surgery. Bleeding at the surgical site may have numerous aetiologies. Fibrinolysis is a rare but dramatic event. CASE REPORT: We report a case with delayed bleeding after excision of a melanoma. The patient was re-operated and a major haemorrhage followed so that a transfusion of blood and fresh frozen plasma was necessary. The biological investigations concluded to a subacute primitive fibrinolysis associated with the melanoma. The patient was first considered to have completely recovered when a blood-borne liver metastasis diffusion rapidly occurred. The patient deceased within a few months from a hepatic encephalopathy with hepatic metastases. DISCUSSION: We find only a few published cases of melanoma with fibrinolysis. Its association with other abnormalities, like a partial factor XIII deficiency, made these abnormalities even more difficult to identify. The relation between the subacute fibrinolysis, the melanoma and the liver infiltrative metastasis is difficult to establish.


Asunto(s)
Fibrinólisis , Melanoma/cirugía , Neoplasias Cutáneas/cirugía , Transfusión Sanguínea , Resultado Fatal , Humanos , Neoplasias Hepáticas/secundario , Masculino , Melanoma/secundario , Persona de Mediana Edad , Reoperación , Neoplasias Cutáneas/patología
19.
Nature ; 437(7058): 519-21, 2005 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-16177783

RESUMEN

To understand the evolution of galaxies, we need to know as accurately as possible how many galaxies were present in the Universe at different epochs. Galaxies in the young Universe have hitherto mainly been identified using their expected optical colours, but this leaves open the possibility that a significant population remains undetected because their colours are the result of a complex mix of stars, gas, dust or active galactic nuclei. Here we report the results of a flux-limited I-band survey of galaxies at look-back times of 9 to 12 billion years. We find 970 galaxies with spectroscopic redshifts between 1.4 and 5. This population is 1.6 to 6.2 times larger than previous estimates, with the difference increasing towards brighter magnitudes. Strong ultraviolet continua (in the rest frame of the galaxies) indicate vigorous star formation rates of more than 10-100 solar masses per year. As a consequence, the cosmic star formation rate representing the volume-averaged production of stars is higher than previously measured at redshifts of 3 to 4.

20.
Int J Pharm ; 299(1-2): 84-91, 2005 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-15970409

RESUMEN

ZK 811 752, a potent candidate for the treatment of autoimmune diseases, demonstrated pH-dependent solubility. The resulting release from conventional mini matrix tablets decreased with increasing pH-values of the dissolution medium. The aim of this study was to overcome this problem and to achieve pH-independent drug release. Mini matrix tablets were prepared by direct compression of drug, matrix former (polyvinylacetate/polyvinylpyrrolidone; Kollidon SR) and excipients (lactose, calcium phosphate or maize starch). To solve the problem of pH-dependent solubility fumaric acid was added to the drug-polymer excipient system. The addition of fumaric acid was found to maintain low pH-values within the mini tablets during release of ZK 811 752 in phosphate buffer pH 6.8. Thus, micro environmental conditions for the dissolution of the weakly basic drug were kept constant and drug release was demonstrated to be pH-independent. Incorporation of water-soluble (lactose) or highly swellable (maize starch) excipients accelerated drug release in a more pronounced manner compared to the water-insoluble excipient calcium phosphate. Stability studies demonstrated no degradation of the drug substance and reproducible drug release patterns for mini matrix tablets stored at 25 degrees C/60% RH and 30 degrees C/70% RH for up to 6 months.


Asunto(s)
Fumaratos/química , Compuestos de Fenilurea/química , Piperidinas/química , Polivinilos/química , Povidona/química , Receptores de Quimiocina/antagonistas & inhibidores , Fosfatos de Calcio/química , Química Farmacéutica , Preparaciones de Acción Retardada , Estabilidad de Medicamentos , Concentración de Iones de Hidrógeno , Lactosa/química , Receptores CCR1 , Solubilidad , Almidón/química , Comprimidos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...