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1.
Brain Behav Immun ; 93: 226-237, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33516921

RESUMEN

While toll-like receptors (TLRs), which mediate innate immunity, are known to play an important role in host defense, recent work suggest their involvement in some integrated behaviors, including anxiety, depressive and cognitive functions. Here, we investigated the potential involvement of the flagellin receptor, TLR5, in anxiety, depression and cognitive behaviors using male TLR5 knock-out (KO) mice. We aobserved a specific low level of basal anxiety in TLR5 KO mice with an alteration of the hypothalamo-pituitary axis (HPA) response to acute restraint stress, illustrated by a decrease of both plasma corticosterone level and c-fos expression in the hypothalamic paraventricular nucleus where TLR5 was expressed, compared to WT littermates. However, depression and cognitive-related behaviors were not different between TLR5 KO and WT mice. Nor there were significant changes in the expression of some cytokines (IL-6, IL-10 and TNF-α) and other TLRs (TLR2, TLR3 and TLR4) in the prefrontal cortex, amygdala and hippocampus of TLR5 KO mice compared to WT mice. Moreover, mRNA expression of BDNF and glucocorticoid receptors in the hippocampus and amygdala, respectively, was not different. Finally, acute intracerebroventricular administration of flagellin, a specific TLR5 agonist, or chronic neomycin treatment did not exhibit a significant main effect, only a significant main effect of genotype was observed between TLR5 KO and WT mice. Together, those findings suggest a previously undescribed and specific role of TLR5 in anxiety and open original prospects in our understanding of the brain-gut axis function.


Asunto(s)
Ansiedad , Receptor Toll-Like 5 , Animales , Ansiedad/genética , Trastornos de Ansiedad , Corticosterona , Masculino , Ratones , Ratones Noqueados , Receptor Toll-Like 5/genética
2.
Ann Chir Plast Esthet ; 65(4): e7-e13, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32482351

RESUMEN

Clitoral hypertrophy is a rare genital malformation that can be congenital or acquired. In congenital forms, the most common cause is adrenal hyperplasia. The acquired forms are caused by endocrinological diseases, benign tumours or cysts. Idiopathic clitoral hypertrophies can be detected after the elimination of secondary causes. A complete assessment is needed to treat the origin of clitoridomegaly. The hypertrophy is often increased or unmasked during sexual arousal with the appearance of a true vulvar appendage in erection. It is often accompanied by a hypertrophy of the clitoral hood and can cause psychological suffering with an impact on the quality of sexual life. When the cause of clitoral hypertrophy is diagnosed, treated or stabilized, the plastic surgeon may be called upon for surgical correction. Reconstructive surgery in this area has evolved considerably since the historical clitoral amputations which led to the current technique of partial resection with sparing the dorsal neurovascular pedicle of the clitoris as described by Professor Paniel. We propose a modified conservative technique to treat clitoral hypertrophy and the clitoral hood and present two clinical cases: ventral reduction clitoridoplasty with preservation of the neurovascular pedicle associated with a chevron plasty of the clitoral hood and a lipofilling of the labia majora. The postoperative follow-up is simple with reports of great satisfaction from patients regarding their quality of life.


Asunto(s)
Procedimientos de Cirugía Plástica , Calidad de Vida , Clítoris/cirugía , Femenino , Humanos , Hipertrofia/cirugía , Vulva/cirugía
3.
Eur J Pain ; 22(1): 127-141, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-28877402

RESUMEN

BACKGROUND: Histamine H3 receptors are mainly expressed on CNS neurons, particularly along the nociceptive pathways. The potential involvement of these receptors in pain processing has been suggested using H3 receptor inverse agonists. METHODS: The antinociceptive effect of S 38093, a novel inverse agonist of H3 receptors, has been evaluated in several neuropathic pain models in rat and compared with those of gabapentin and pregabalin. RESULTS: While S 38093 did not change vocalization thresholds to paw pressure in healthy rats, it exhibited a significant antihyperalgesic effect in the Streptozocin-induced diabetic (STZ) neuropathy model after acute and chronic administration and, in the chronic constriction injury (CCI) model only after chronic administration, submitted to the paw-pressure test. Acute S 38093 administration at all doses tested displayed a significant cold antiallodynic effect in a model of acute or repeated administration of oxaliplatin-induced neuropathy submitted to cold tail immersion, cold allodynia being the main side effect of oxaliplatin in patients. The effect of S 38093 increased following chronic administration (i.e. twice a day during 5 days) in the CCI and STZ models except in the oxaliplatin models where its effect was already maximal from the first administration The kinetics and size of effect of S 38093 were similar to gabapentin and/or pregabalin. Finally, the antinociceptive effect of S 38093 could be partially mediated by α2 adrenoreceptors desensitization in the locus coeruleus. CONCLUSIONS: These results highlight the interest of S 38093 to relieve neuropathic pain and warrant clinical trials especially in chemotherapeutic agent-induced neuropathic pain. SIGNIFICANCE: S 38093, a new H3 antagonist/inverse agonist, displays antiallodynic and antihyperalgesic effect in neuropathic pain, especially in oxaliplatin-induced neuropathy after chronic administration. This effect of S 38093 in neuropathic pain could be partly mediated by α2 receptors desensitization in the locus coeruleus.


Asunto(s)
Analgésicos/uso terapéutico , Antagonistas de los Receptores Histamínicos/uso terapéutico , Hiperalgesia/tratamiento farmacológico , Neuralgia/tratamiento farmacológico , Aminas/farmacología , Aminas/uso terapéutico , Analgésicos/farmacocinética , Animales , Ácidos Ciclohexanocarboxílicos/farmacología , Ácidos Ciclohexanocarboxílicos/uso terapéutico , Modelos Animales de Enfermedad , Gabapentina , Antagonistas de los Receptores Histamínicos/farmacología , Hiperalgesia/inducido químicamente , Masculino , Neuralgia/inducido químicamente , Compuestos Organoplatinos , Oxaliplatino , Umbral del Dolor/efectos de los fármacos , Pregabalina/farmacología , Pregabalina/uso terapéutico , Ratas , Ratas Sprague-Dawley , Ácido gamma-Aminobutírico/farmacología , Ácido gamma-Aminobutírico/uso terapéutico
4.
Gynecol Obstet Fertil Senol ; 45(11): 584-589, 2017 Nov.
Artículo en Francés | MEDLINE | ID: mdl-28967599

RESUMEN

OBJECTIVE: To evaluate the pertinence of Kleihauer-Betke (KB) test, in case of abdominal trauma during pregnancy in forecast of fetal outcomes, according to trauma severity. METHODS: A single-center retrospective study conducted between January 2014 and April 2016 in a maternity type III and a trauma center, which included the pregnant women admitted for abdominal trauma. The trauma's severity was assessed using the guidelines of the Society of Obstetricians and Gynaecologists of Canada. The impact of a positive KB test, defined as>0.1%, was analyzed. Adverse outcome was defined as one or more of the following complications: intrauterine fetal death, placental abruption, pre-term birth<37 weeks of gestation, and fetal or neonatal anemia. RESULTS: During the study period, 265 pregnancies involved into an abdominal trauma were included: 69% with a minor trauma and 31% with a severe trauma. Of all patients, 5.6% presented a positive KB test, among then 15.4% had an adverse outcome. There was no significant difference in the rate of adverse outcomes in the positive KB group and the KB negative group either in the overall population (P=0.16), in the minor trauma population (P=1) or in the major trauma population (P=0.14). The predictive positive values were respectively in the global population, in the minor trauma group and in the severe trauma group 15.4%, 0% and 25%. CONCLUSIONS: The KB test does not seem to be useful in case of trauma during pregnancy to define adverse outcome.


Asunto(s)
Traumatismos Abdominales/complicaciones , Complicaciones del Embarazo , Lesiones Prenatales/diagnóstico , Adulto , Canadá , Eritrocitos/citología , Femenino , Sangre Fetal , Transfusión Fetomaterna/diagnóstico , Transfusión Fetomaterna/etiología , Feto , Humanos , Embarazo , Resultado del Embarazo/epidemiología , Estudios Retrospectivos
5.
J Gynecol Obstet Hum Reprod ; 46(1): 43-51, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28403956

RESUMEN

OBJECTIVES: To evaluate the risk of severe perineal tear following instrumental vaginal delivery (IVD) performed with spatulas and vacuum extraction. Secondary objectives were to estimate the impact of episiotomy on this risk. METHODS: From December 2008 to October 2012, women who underwent spatulas or vacuum were prospectively included. Each spontaneous vaginal delivery (SVD) following each included IVD were included as control cases (1-1 ratio). Careful perineal examination was systematically performed. Severe perineal tear was defined by the occurrence of anal sphincter rupture with or without anal mucosa tear. RESULTS: A total of 761 patients were included in the current study: 248 (64%) spatulas, 137 (36%) vacuums and 381 (49%) SVDs. Severe perineal tear was diagnosed in 19 (2.5%) cases. Episiotomy had been performed in 276 (36.9%) patients. Only spatulas extraction was found to significantly increase the risk of severe perineal tear (AOR=7.66; 95% CI: 2.06-28; P=0.02). Although vacuum extraction seemed to increase this risk, it was not found to be significant (AOR=3.25; 95% CI: 0.65-16.24; P=0.15). No significant difference was observed between the risk of severe perineal tear following spatulas and vacuum (AOR=2.36; 95% CI: 0.63-8.82; P=0.202). Finally, neither foetal macrosomia, nor episiotomy, nor foetal extraction with the head in the deep pelvis, nor delivery at night had a significant impact on the probability of severe perineal tear. CONCLUSIONS: Spatulas extraction is an independent risk factor for severe perineal tear. The practice of episiotomy was not shown to have any significant impact on this risk.


Asunto(s)
Forceps Obstétrico/efectos adversos , Perineo/lesiones , Extracción Obstétrica por Aspiración/efectos adversos , Adulto , Canal Anal/lesiones , Estudios de Casos y Controles , Estudios de Cohortes , Episiotomía/estadística & datos numéricos , Femenino , Humanos , Mucosa Intestinal/lesiones , Perineo/cirugía , Embarazo , Rotura
6.
Commun Agric Appl Biol Sci ; 79(3): 525-34, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-26080487

RESUMEN

DISCUSS, the Dual Indicator Set for Sustainable Crop protection Sustainability Surveys, was designed to help farmers achieve more sustainable crop protection. The indicator set pairs risk indicators--POCER--, with response indicators--a management questionnaire. Both parts of DISCUSS are indicators in their own right, but the dual risk-response setup has the additional trump that the questionnaire reveals farm level information, by which POCER calculations are refined. Simulations with personal protection and drift mitigation measures illustrate how DISCUSS can be used to support the farmers' crop protection decisions.


Asunto(s)
Agricultura/métodos , Conservación de los Recursos Naturales , Ambiente , Humanos , Exposición Profesional/efectos adversos , Exposición Profesional/prevención & control , Plaguicidas/toxicidad , Encuestas y Cuestionarios , Recursos Humanos
7.
J Fish Biol ; 82(5): 1728-32, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23639167

RESUMEN

To assess the correlation between four visual morphological types based on body colour and shape (fario trout, FT; shiny fario, SFT; presmolt trout, PST; typical smolt ST) of juvenile brown trout Salmo trutta during downstream spring migration and the biological form at the adult stage (river or sea), mark-recapture experiments were carried out over a period of 23 years. Evidence is provided that the visual SFT type is not a relevant one, while objective colorimetric measurements using a black basin are the best way to determine the morphological type in migrating juveniles.


Asunto(s)
Migración Animal , Pigmentos Biológicos/fisiología , Maduración Sexual/fisiología , Trucha/anatomía & histología , Trucha/fisiología , Animales
8.
Diabetes Metab ; 38(1): 14-9, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22284547

RESUMEN

AIMS: To assess the success of dental-implant treatment in patients with diabetes. BACKGROUND: Dental-implant treatment is an efficient means of replacing lost teeth. However, diabetes can be considered a relative contraindication for this type of treatment because of the slightly higher failure rate compared with populations without diabetes. RECOMMENDATIONS: Prerequisite selection of suitable diabetic patients, eradication of co-morbidities (poor oral hygiene, cigarette-smoking, periodontitis), stabilization of glycaemic control (HbA(1c) at around 7%) and preventative measures against infection can increase the success of dental implantation in diabetic patients to a satisfactory rate of 85-95%. CONCLUSION: Implant surgery is never a matter of urgency; thus, diabetes patients with the best chances of success should be conjointly selected and prepared by both dental and diabetes clinicians.


Asunto(s)
Glucemia/metabolismo , Implantes Dentales , Diabetes Mellitus Tipo 2 , Hemoglobina Glucada/metabolismo , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/cirugía , Femenino , Humanos , Masculino , Oseointegración , Selección de Paciente , Periodontitis/complicaciones , Pérdida de Diente , Resultado del Tratamiento
10.
Osteoporos Int ; 22(6): 1755-64, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20838767

RESUMEN

UNLABELLED: Identification of older men at high risk of peripheral fracture can be improved by assessing prevalent fractures (men aged ≤ 65), history of falls (men aged >65), bone width, and aortic calcifications. INTRODUCTION: Low bone mineral density (BMD) identifies 20% of men who sustain osteoporotic fracture. We studied (1) if the assessment of bone width, aortic calcifications, prevalent falls and fractures improves identification of men at high risk of fracture and (2) if the predictive value of these parameters varies with age. METHODS: Among 781 men aged 50 and over, 61 men sustained 66 low-trauma peripheral fractures during 10 years. History of falls and prevalent fractures was assessed by questionnaire. BMD and bone with were measured by dual X-ray absorptiometry. Abdominal aortic calcifications were assessed on the lateral radiographs of the lumbar spine. RESULTS: Low BMD, low bone width, extended aortic calcifications, prevalent fractures (mainly multiple fractures) and frequent falls were all associated independently with higher risk of fracture. In men aged ≤ 65, prevalent fractures are associated with a significant increase in the risk of fracture (two- to threefold for one and four- to fivefold for multiple prevalent fractures). In men aged >65, history of falls is associated with a higher risk of fracture, e.g. frequent falls are associated with a sixfold increase in the risk of fracture. CONCLUSIONS: Men aged ≤ 65 with multiple prevalent fractures and frequent fallers aged >65 are at particularly high risk of peripheral fracture regardless of BMD.


Asunto(s)
Fracturas Osteoporóticas/etiología , Accidentes por Caídas/estadística & datos numéricos , Factores de Edad , Anciano , Anciano de 80 o más Años , Enfermedades de la Aorta/epidemiología , Índice de Masa Corporal , Densidad Ósea/fisiología , Métodos Epidemiológicos , Francia/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Fracturas Osteoporóticas/epidemiología , Fracturas Osteoporóticas/fisiopatología , Recurrencia , Calcificación Vascular/epidemiología
12.
J Sports Med Phys Fitness ; 51(4): 670-5, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22212271

RESUMEN

AIM: The aim To assess the effects of a unique twelve month program of physical activity and health education on body mass index, cardiorespiratory fitness and physical activity habits in obese youth. METHODS: Thirty-seven physician referred subjects, nineteen girls (12.7 ± 3.1 years) and eighteen boys (12.2 ± 2.8 years) participated in the study. Treatment consisted of a unique program of physical activity that emphasized playing games. Activity sessions were offered one time per week, two hours each session, for twelve months. A two hour health education class was provided every 3 months. Weight, height, Body Mass Index, cardiorespiratory fitness and habitual physical activity were measured. RESULTS: Findings of the study demonstrated a significant improvement in body mass index, cardiorespiratory fitness (P<0.001), and habitual physical activity (P<0.05). CONCLUSION: Results of the pilot study were favorable in addressing serious health issues in young obese boys and girls.


Asunto(s)
Terapia por Ejercicio , Ejercicio Físico/fisiología , Educación en Salud , Obesidad/terapia , Adolescente , Conducta del Adolescente , Índice de Masa Corporal , Niño , Prueba de Esfuerzo , Terapia por Ejercicio/psicología , Femenino , Conductas Relacionadas con la Salud , Humanos , Masculino , Actividad Motora/fisiología , Obesidad/metabolismo , Consumo de Oxígeno , Proyectos Piloto
13.
Gynecol Obstet Fertil ; 37(5): 389-95, 2009 May.
Artículo en Francés | MEDLINE | ID: mdl-19410494

RESUMEN

OBJECTIVES: Law no. 2001-588 of 4 July 2001 liberalised the practice of tubal sterilisation in France, at the same time as a new hysteroscopic method of female sterilization appeared. The growth of this method has been spurred by the reduced need for analgesia, absence of incision and scar, reduced duration of hospitalization and diminution of costs. The aim of this study was to analyse the use of the Essure procedure in France. PATIENTS AND METHODS: This multicentre study covered seven French facilities from January 2004 through June 2006. This study included 1061 attempted placements of the Essure micro-insert, marketed by Conceptus SAS (France). RESULTS: The first placement attempt was successful in 992 cases (94.4%). The success rate for second attempts was 59% (n = 23). Mean VAS was 3,23 +/- 0.19. Ninety-three percent of patients undergoing Essure placement were satisfied or very satisfied. DISCUSSION AND CONCLUSION: Tubal sterilisation with Essure micro-inserts is a reliable and reproducible method that requires a short period of training. In the future, the hysteroscopic pathway will replace the laparoscopic route.


Asunto(s)
Esterilización Tubaria/instrumentación , Esterilización Tubaria/legislación & jurisprudencia , Esterilización Tubaria/métodos , Femenino , Francia , Humanos , Laparoscopía/métodos , Satisfacción del Paciente/economía , Embarazo , Esterilización Reproductiva/métodos , Esterilización Tubaria/economía , Esterilización Tubaria/estadística & datos numéricos , Resultado del Tratamiento
14.
J Neurosci ; 26(42): 10856-67, 2006 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-17050723

RESUMEN

Chondroitin sulfate proteoglycans (CSPGs) are inhibitory extracellular matrix molecules that are upregulated after CNS injury. Degradation of CSPGs using the enzyme chondroitinase ABC (ChABC) can promote functional recovery after spinal cord injury. However, the mechanisms underlying this recovery are not clear. Here we investigated the effects of ChABC treatment on promoting plasticity within the spinal cord. We found robust sprouting of both injured (corticospinal) and intact (serotonergic) descending projections as well as uninjured primary afferents after a cervical dorsal column injury and ChABC treatment. Sprouting fibers were observed in aberrant locations in degenerating white matter proximal to the injury in regions where CSPGs had been degraded. Corticospinal and serotonergic sprouting fibers were also observed in spinal gray matter at and below the level of the lesion, indicating increased innervation in the terminal regions of descending projections important for locomotion. Spinal-injured animals treated with a vehicle solution showed no significant sprouting. Interestingly, ChABC treatment in uninjured animals did not induce sprouting in any system. Thus, both denervation and CSPG degradation were required to promote sprouting within the spinal cord. We also examined potential detrimental effects of ChABC-induced plasticity. However, although primary afferent sprouting was observed after lumbar dorsal column lesions and ChABC treatment, there was no increased connectivity of nociceptive neurons or development of mechanical allodynia or thermal hyperalgesia. Thus, CSPG digestion promotes robust sprouting of spinal projections in degenerating and denervated areas of the spinal cord; compensatory sprouting of descending systems could be a key mechanism underlying functional recovery.


Asunto(s)
Condroitina ABC Liasa/fisiología , Vértebras Lumbares/enzimología , Regeneración Nerviosa/fisiología , Traumatismos de la Médula Espinal/enzimología , Traumatismos de la Médula Espinal/terapia , Animales , Condroitina ABC Liasa/administración & dosificación , Inyecciones Espinales , Masculino , Plasticidad Neuronal/fisiología , Ratas , Ratas Wistar , Traumatismos de la Médula Espinal/fisiopatología , Factores de Tiempo
15.
Hum Reprod ; 21(11): 2817-22, 2006 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-16877376

RESUMEN

BACKGROUND: In women with chronic anovulation, the choice of the FSH starting dose and the modality of subsequent dose adjustments are critical in controlling the risk of overstimulation. The aim of this prospective randomized study was to assess the efficacy and safety of a decremental FSH dose regimen applied once the leading follicle was 10-13 mm in diameter in women treated for WHO Group II anovulation according to a chronic low-dose (CLD; 75 IU FSH for 14 days with 37.5 IU increment) step-up protocol. METHODS: Two hundred and nine subfertile women were treated with recombinant human FSH (r-hFSH) (Gonal-f) for ovulation induction according to a CLD step-up regimen. When the leading follicle reached a diameter of 10-13 mm, 158 participants were randomized by means of a computer-generated list to receive either the same FSH dose required to achieve the threshold for follicular development (CLD regimen) or half of this FSH dose [sequential (SQ) regimen]. HCG was administered only if not more than three follicles >or=16 mm in diameter were present and/or serum estradiol (E(2)) values were <1200 pg/ml. The primary outcome measure was the number of follicles >or=16 mm in size at the time of hCG administration. RESULTS: Clinical characteristics and ovarian parameters at the time of randomization were similar in the two groups. Both CLD and SQ protocols achieved similar follicular growth as regards the total number of follicles and medium-sized or mature follicles (>/=16 mm: 1.5 +/- 0.9 versus 1.4 +/- 0.7, respectively). Furthermore, serum E(2) levels were equivalent in the two groups at the time of hCG administration (441 +/- 360 versus 425 +/- 480 pg/ml for CLD and SQ protocols, respectively). The rate of mono-follicular development was identical as well as the percentage of patients who ovulated and achieved pregnancy. CONCLUSIONS: The results show that the CLD step-up regimen for FSH administration is efficacious and safe for promoting mono-follicular ovulation in women with WHO Group II anovulation. This study confirms that maintaining the same FSH starting dose for 14 days before increasing the dose in step-up regimen is critical to adequately control the risk of over-response. Strict application of CLD regimen should be recommended in women with WHO Group II anovulation.


Asunto(s)
Anovulación/tratamiento farmacológico , Hormona Folículo Estimulante Humana/uso terapéutico , Relación Dosis-Respuesta a Droga , Femenino , Hormona Folículo Estimulante Humana/administración & dosificación , Humanos , Infertilidad Femenina/tratamiento farmacológico , Selección de Paciente , Embarazo , Resultado del Embarazo , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/uso terapéutico , Seguridad , Resultado del Tratamiento
16.
Int J Sports Med ; 27(8): 623-8, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16874589

RESUMEN

A variety of testing procedures are used to assess the effects of particular treatments on the training status of athletes. The present study aims to investigate the reproducibility of selected tests in swimming. Sixteen trained swimmers performed three kinds of test: 1) Constant Distance Test (CDT), 2) Constant Time Test (CTT), and 3) Constant Velocity Test (CVT). The analysis of the reproducibility was based on a test-retest procedure. The test-retest performances were highly correlated for the three kinds of test (r = 0.98, 0.98, and 0.93 for CDT, CTT and CVT, respectively). The mean Coefficient of Variation (CV) was computed between test-retest for each subject and each procedure. A repeated measures one-way ANOVA showed that CVT was significantly less reliable (CV = 6.46 +/- 6.24 %) than CDT and CTT (CV = 0.56 +/- 0.6 0 % and 0.63 +/- 0.54 % respectively) (p < 0.001). Psychological factors and a lack of familiarity with CVT (not extensively used during training session) could explain its greater variability. Thus, CDT and CTT seem to be the most reliable tests to detect the smallest meaningful change in the training status of swimmers. Post-hoc power calculations of the experimental design showed the sample size would have to increase to 80, 113, and 228 subjects for CWT, CDT and CPT respectively, to reach a power of 80 %. The minimal detectable differences have to be calculated to ensure a real effect of a particular treatment on a group of swimmers, according to the kind of test used.


Asunto(s)
Prueba de Esfuerzo , Educación y Entrenamiento Físico , Natación/fisiología , Adulto , Análisis de Varianza , Femenino , Humanos , Masculino , Resistencia Física/fisiología , Reproducibilidad de los Resultados
17.
New Phytol ; 170(2): 291-300, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16608454

RESUMEN

Extreme temperature events are projected to increase in frequency in a future climate. As successive extremes could occur more frequently, patches of vulnerable tundra vegetation were exposed to two consecutive heat waves (HWs) of 10 d each, with a 5-d recovery period in between. Surface temperatures during the HWs were increased approximately 6 degrees C using infrared irradiation sources. In three of the four target species (Pyrola grandiflora, Polygonum viviparum and Carex bigelowii), plant conditions improved upon the first exposure. Depending on species, leaf relative growth, leaf chlorophyll content or maximal photochemical efficiency was increased. In P. grandiflora the positive effects of the heat on the photosynthetic apparatus led to augmented net photosynthesis. By contrast, Salix arctica responded mainly negatively, indicating species-specific responses. During the second HW, leaf mortality suddenly increased, indicating that the heat stress induced by the extreme events lasted too long and negatively influenced the species resistance to high temperature. After the HWs, when plants were exposed to (low) ambient temperatures again, plant performance deteriorated further, indicating possible loss of cold resistance.


Asunto(s)
Clima Frío , Calor , Hojas de la Planta/crecimiento & desarrollo , Regiones Árticas , Carex (Planta)/crecimiento & desarrollo , Carex (Planta)/fisiología , Clorofila/metabolismo , Ericaceae/crecimiento & desarrollo , Ericaceae/fisiología , Fluorescencia , Efecto Invernadero , Fotosíntesis/fisiología , Complejo de Proteína del Fotosistema II/fisiología , Hojas de la Planta/fisiología , Polygonum/crecimiento & desarrollo , Polygonum/fisiología , Salix/crecimiento & desarrollo , Salix/fisiología , Especificidad de la Especie
18.
Int J Sports Med ; 26(6): 471-5, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16037890

RESUMEN

The purpose of this study was to analyse the effects of an exhaustive exercise on arm coordination and intracyclic velocity variations (IVV) to better understand the ways in which they are modified under fatigue conditions. Seventeen competitive swimmers performed a 200-m all-out test and a set of two 25-m (before and after the 200-m) at maximal intensity to measure stroking parameters, IVV, and the relative duration of the different parts of the stroke cycle and identify the model of arm coordination by using the index of coordination (IdC). Results showed an increase in the relative duration of the propulsive time, which induced a change in arm coordination as fatigue developed in relation to a decrease in stroke length (SL) and stroke rate (SR) (p<0.05). The evolution of IdC corresponds to a reduction of the non-propulsive lag time between the two arms' propulsive actions. Despite these modifications, IVV were not significantly modified (p<0.05). The present results highlighted that IdC and relative durations of each part of the cycle (particularly the pull phase) could be assessed to complete the "SL x SR" model and to partly understand the technique modifications under fatigue condition.


Asunto(s)
Brazo/fisiología , Ejercicio Físico/fisiología , Resistencia Física/fisiología , Natación/fisiología , Análisis y Desempeño de Tareas , Adulto , Femenino , Humanos , Ácido Láctico/sangre , Masculino , Consumo de Oxígeno/fisiología , Desempeño Psicomotor/fisiología
19.
Bone ; 36(1): 13-21, 2005 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-15663998

RESUMEN

In the skeleton of elderly men, two opposite activities occur: bone loss at the endosteal envelope, which increases bone fragility, and periosteal apposition, which improves bending strength of bone. Both may contribute to serum bone formation markers although they have an opposite effect on bone fragility. The aim of this study was to determine if circulating bone formation markers reflect periosteal bone formation and endosteal bone remodelling in 640 men aged 55-85 years belonging to the MINOS cohort. We measured biochemical markers of bone formation (osteocalcin, bone alkaline phosphatase, N-terminal extension propeptide of type I collagen) and bone resorption (urinary and serum beta-isomerised C-terminal telopeptide of collagen type I, total and free deoxypyridinoline). Parameters of bone size (cross-sectional surface of third lumbar vertebral body measured by X-ray, projected areas of total hip, femoral neck, radius and ulna measured by dual-energy X-ray absorptiometry) increased with age (r = 0.20-0.32, P < 0.0001). In contrast, parameters related to bone loss (areal bone mineral density [aBMD], volumetric bone mineral density [vBMD] and cortical thickness) and determined mainly by bone resorption, decreased with ageing (r = -0.14 to -0.23, P < 0.005-0.0001). Men in the highest quartile of bone resorption markers had lower aBMD (3.8-10.2%, P < 0.05-0.0001), lower vBMD (3.9-13.0%, P < 0.05-0.0001), and lower cortical thickness (1.5-9.6%, P < 0.05-0.0001) than men in the lowest quartile. Markers of bone resorption were not significantly associated with estimates of bone size at any skeletal site. Markers of bone formation were not associated with estimates of periosteal formation after adjustment for covariates. In contrast, men in the highest quartile of the bone formation markers had significantly lower aBMD (4.0-11.7%, P < 0.05-0.0001), lower vBMD (4.2-16.3, P < 0.05-0.0001) and lower cortical thickness (4.0-7.4%, P < 0.05-0.0001) than men in the lowest quartile. In summary, serum levels of bone formation markers are negatively correlated with the estimates of endosteal bone loss. In contrast, they disclose no association with parameters reflecting periosteal apposition. Thus, in elderly men, bone formation markers reflect endosteal bone remodelling, probably because of the coupling between resorption and formation activities. In contrast, they do not reflect the periosteal bone formation, probably because the periosteal surface is smaller and has a slower remodelling rate than the endosteal surface.


Asunto(s)
Biomarcadores/metabolismo , Resorción Ósea/metabolismo , Absorciometría de Fotón , Anciano , Anciano de 80 o más Años , Densidad Ósea , Humanos , Masculino , Estudios Prospectivos
20.
Int J Sports Med ; 26(1): 53-8, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15643535

RESUMEN

In order to increase or maintain speed at sub-maximal intensities, well-trained swimmers have an increase in their stroke rate, thus a decrease in their stroke. The purposes of this study were i) to ascertain whether the maximal speed from which the stroke length decreases significantly (SSLdrop) corresponds to the maximal lactate steady state swimming speed (SMLSS), and ii) to examine the effect of the exercise duration on the stroking parameters above, below, and at SMLSS. Eleven male well-trained swimmers performed an all-out 400-m front crawl test to estimate maximal aerobic speed (MAS) and four sub-maximal 30-min tests (75, 80, 85, and 90 % MAS) to determine SMLSS and SSLdrop and to analyse the evolution of the stroking parameters throughout these tests. SMLSS (88.9 +/- 3.3 % MAS) and SSLdrop (87.3 +/- 4.5 % MAS) were not significantly different from each other (p=0.41) and were highly correlated (r=0.88; p <0.001). Moreover, a slight stroke rate increase, and a stroke length decrease, were observed above S (MLSS) but were only significant for the 5 swimmers unable to maintain this speed for 30 min (p >0.05). During the 30-min tests swum below and at SMLSS, a steady state of stroking parameters was statistically reported. Thus, SMLSS seems to represent not only a physiological transition threshold between heavy and severe sub-maximal intensities but also a biomechanical boundary beyond which the stroke length becomes compromised.


Asunto(s)
Ácido Láctico/sangre , Natación/fisiología , Análisis y Desempeño de Tareas , Adulto , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Consumo de Oxígeno/fisiología
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