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R Revilla

Publications and source records attributed to R Revilla.

17 recordsLinked to original sources
PubMed2003

Effects of suckling frequency and breed on productive performance, follicular dynamics and postpartum interval in beef cows.

One experiment was conducted to determine the influence of suckling frequency (restricted suckling (RS) versus ad libitum suckling (AS)) and breed (Brown Swiss versus Pirenaica) on productive performance, follicular dynamics and postpartum cyclicity resumption in beef cows. Twenty-four spring-calving cows (12 Brown Swiss and 12 Pirenaica) were used. After calving cows were assigned, within breed, to the two suckling frequencies (RS versus AS). During the postpartum period, cows were fed 100% of the daily energy estimated requirements. The study was conducted from calving to either day 90 postpartum or to detection of the second ovulation whenever it came later. The pattern of follicular development was monitored daily by transrectal ultrasonography, and blood samples were collected three times a week to analyse progesterone concentrations by RIA. Body condition score at calving was 2.5 (from 1 to 5). Productive parameters were not significantly affected by suckling frequency. Pirenaica cows gained more weight (P<0.001), while Brown Swiss cows had higher milk yield (P<0.001) and thus their calves grew faster (P<0.05). In the present moderate conditions of nutrition, either suckling frequency or breed did not affect follicular dynamics (on average there were 6.5 follicles in emergence, growth rate of dominant follicle (DF) was 1.3mm per day and maximum diameter of dominant follicle was 13.9mm). There were gradual increases in maximum diameter and growth rate of dominant follicle related to the proximity of the ovulatory waves, and they were defined by third order polynomial equations. Postpartum anoestrous interval (PPI) was markedly affected by the interaction between suckling frequency and breed (P<0.001): ad libitum suckling prolonged significantly the interval from calving to first ovulation in Brown Swiss cows (31.8 day versus 82.7 day, in RS and AS groups, respectively, P<0.05), but not in Pirenaica cows (43.5 day versus 32.6 day, in RS and AS groups, respectively, not statistically significant). It is concluded that in moderate pre- and postpartum nutritional conditions Brown Swiss cows were more susceptible to the suppressor effect of ad libitum suckling on postpartum anoestrous interval than Pirenaica cows, although this breed difference did not seem to be mediated by differences in energy balance or in ovarian follicular dynamics.

Animal Nutritional Physiological Phenomena↗
PubMed2002

Factors affecting animal performance during the grazing season in a mountain cattle production system.

The factors influencing weight changes during the grazing season of Brown Swiss autumn-calving cows and Brown Swiss and Pirenaica spring-calving cows and their calves were studied over an 8-yr period in Spanish mountain conditions. The data set comprised 552 annual production cycles of cows that calved in two consecutive years. The animals grazed on alpine ranges during the summer and on forest pastures in the spring and autumn. They were housed during the winter and fed at different feeding levels (83 to 117% of their energy requirements) throughout the years of study. Weights were recorded every 3 mo and corrected to account for changes of digestive content and fetal growth, using theoretical relationships. Cow weight gains both on forest pastures and high mountain ranges were higher in autumn- than in spring-calving Brown Swiss cows, and therefore also during the whole grazing season (52.1 vs 7.7 kg, respectively, P < 0.001). Therefore, weight at calving and thereafter was significantly higher in autumn- than in spring-calving cows, which was associated with better reproductive performance (35.5 vs 49.1 d from calving to first ovulation, P < 0.01). In the spring-calving herd, Pirenaica cows had slightly higher gains than Brown Swiss cows during the grazing period (18.5 vs 7.7 kg, P < 0.001), mainly due to their higher gains on forest pastures, but their reproductive performance was similar (44.5 vs 49.1 d from calving to first ovulation, respectively, not statistically significant). Gains were higher in multiparous than in primiparous cows (31.1 vs 14.1 kg, respectively, P < 0.001), especially in the case of Brown Swiss cows, which were younger at first calving. Gains were affected by year of study (P < 0.001) and previous weight changes during the housing period (r = -0.35 and r = -0.21 in autumn- and spring-calving cows respectively, P < 0.001). In the case of autumn-calving cows, performance on pasture was also affected by the stage of pregnancy at housing (r = -0.51, P < 0.001). Growth rates through lactation were higher in autumn- than in spring-born calves (P < 0.001), although the shorter lactation period resulted in lower weight at weaning of the former (P < 0.001). Breed was a significant source of variation in the performance of spring-born calves, weights and gains being higher in Brown Swiss than in Pirenaica calves (P < 0.001).

Animal Feed↗
PubMed2001

Norepinephrine, epinephrine and MHPG levels in chick brain development.

In this study we determined the norepinephrine (NE), epinephrine and methoxy-hydroxy-phenyl-glycol (MHPG) levels in dissected chick telencephalon, diencephalon/mesencephalon and cerebellum in a number of stages from the late embryonic period (E16, E17, E18 and E19) and post-hatching period (P1, P2, P3, P4, P5, P15 and P30) using HPLC coupled with a coulometric detection system. A mobile phase which permits the detection of NE, epinephrine and MHPG simultaneously is also described. During development, NE levels increase dramatically after hatching in all brain structures studied and are not correlated in the same period with an increase in the MHPG/NE ratio. The values obtained for epinephrine and MHPG were significantly lower than the NE values in all the structures and stages studied. Our results support the notion of a specific role for NE during the first days after hatching.

Animals↗
PubMed2000

Autoradiographic characterisation of beta-adrenoceptors in chick brain using [3H]CGP 12177.

An autoradiographic method for labelling beta(1)- and beta(2)-adrenoceptors using [3H]CGP 12177 as a radioligand is described as well as the procedure for an autoradiographic saturation kinetic study. The method afforded higher quality autoradiographs as well as an improvement in the tissue preservation when assayed in birds and chick embryos. The results confirmed the K(d) values previously reported for membrane homogenate binding. The use of different radioligands to characterise beta-adrenoceptors, the higher B(max) values found with autoradiography than those obtained by the membrane homogenate binding method and the typical errors in quantifying autoradiography are discussed. It is concluded that the method described here considerably improves autoradiographic beta-adrenergic characterisation.

Animals↗
PubMed2000

Preweaning growth curves in Brown Swiss and Pirenaica calves with emphasis on individual variability.

A quadratic polynomial model with random regression coefficients was used to describe preweaning growth curves of two beef cattle breeds widely used in the Spanish Pyrenees, according to genotype and season of birth effects. In addition, parameters of individual variability that can be used in a stochastic model were obtained. Data recorded indoors from birth to weaning of 217 Brown Swiss calves (3,509 observations) born either in spring or autumn (BS-S, BS-A) and 101 spring-born Pirenaica calves (PI-S, 967 observations) were analyzed. A quadratic model accurately fitted the preweaning weights (R2 = .99). Use of random regression coefficients improved the weaning weight adjustment; the residual variance of the model with intercept and linear random coefficients (9.61 kg2) was smaller than that of the model without them (130.03 kg2). Brown Swiss-S and PI-S calves had similar birth weight (40.9 +/- .96 vs 39.4 +/- .73 kg), but BS-S calves achieved significantly higher weaning weights at 150 d of age (175.2 +/- 2.45 vs 158.4 +/- 3.17 kg). Preweaning growth patterns were different for each season of birth, but there were no differences in weaning weight at 150 d of age (172.9 +/- 2.01 BS-A vs 175.2 +/- 2.45 BS-S). Standardization of weaning weights using a linear approximation could lead to biases, especially when comparing animals from the two calving seasons. The estimate of variances of random parameters should be done within breed and season of birth in order to take into account heteroscedasticity. The variances for BS-A, BS-S, and PI-S were 39.9, 57.6, and 32.2 kg2 for the intercept, respectively, and .0159, .0141, and .0205 kg2 for the linear coefficient. Covariance between the intercept and the linear coefficient (.34 kg2) was only statistically significant in the case of BS-S. The individual variance of weight at 150 d was 424.7 kg2 and 526.7 kg2 for BS-S and PI-S, respectively, almost 65% of the observed variance of weaning weight.

Animals↗
PubMed1999

A comparative study of the beta-adrenoceptors in higher song nuclei of birds.

The present study analyses the presence of beta-adrenoceptors in the main telencephalic song nuclei of the goldfinch and parakeet, species belonging to the two most important groups of birds that reproduce learned songs: oscine songbirds and parrots, respectively. Brains of both species sectioned at appropriate levels were used to perform autoradiographic saturation studies using [3H]CGP 12177 as a radioligand. The results show similar K(D)values for both species (0.1-0.3 nM) and striking differences in Bmax. Thus, beta-adrenoceptors are abundant in the telencephalic vocal control nuclei of the parakeet but not of the goldfinch. The predominance of the beta2 subtype in the song nuclei of both species is also confirmed. We conclude that these receptors could be involved in functions unique to the parakeet and therefore may contribute to the greater flexibility of the vocal system of this species. Our findings also support the possible involvement of beta-adrenoceptors in the evolution of the avian brain.

Adrenergic beta-Agonists↗
PubMed1998

Pre- and post-hatching developmental changes in beta-adrenoceptor subtypes in chick brain.

This study used [3H]CGP 12177 as a radioligand to determine the beta1 and beta2-adrenoceptor changes from the pre-hatching E17 stage, where the beta2 subtype is first detected, to the post-hatching P30 stage. While beta1-adrenoceptors were found to be present from E18 and were limited to cerebellum and hyperstriatum in all stages studied, beta2-adrenoceptors showed a wider distribution throughout the brain. In most of the structures analysed both beta1- and beta2-adrenoceptor binding values reached a maximum in the P2 stage, followed by a decrease over the following days. A second increase in both subtypes was detected again in the P15 and P30 stages. These results support the notion of a specific role for beta-adrenoceptors in neural plasticity in the first week after hatching and suggest that the beta2 subtype is the main adrenoceptor in chick brain throughout its development.

Adrenergic beta-Agonists↗
PubMed1998

Changes in body composition in women treated with gonadotropin-releasing hormone agonists.

OBJECTIVE: The changes that agonists of gonadotropin-releasing hormone (GnRH) produce in mineral bone mass are known, but, as far as we know, those produced by these agents in other body compartments are unknown. METHODS: We studied these changes using dual-energy X-ray absorptiometry in 50 eugonadal women treated with decapeptyl (Triptoreline), 3.75 mg injected intramuscularly, at 28-day intervals for 6 months. RESULTS: There were significant increases in fat content (9.5%, P < 0.0005) and weight (1.3%, P < 0.01), and significant decreases in fat-free mass (-1.9%, P < 0.0001) and water content (-1.8%, P < 0.0002). Bone mass was lost in the axial skeleton (-3.6%, P < 0.0001) but not in the peripheral skeleton. CONCLUSIONS: The changes induced in body composition by the GnRH agonists are similar to those of natural menopause.

Absorptiometry, Photon↗
PubMed1998

A comparative study of the beta-adrenoceptors in higher visual centres of birds.

This report describes the distribution of beta-adrenergic receptors in the telencephalic visual nuclei of chick, duck, pigeon, parakeet and goldfinch using [3H]CGP 12177 (4-3-t-butylamino-2-hydroxypropoxy-[5,7(3)H] benzimidazol-2-one) as a radioligand. The results reveal a predominance of the beta2-adrenoceptor subtype in all the species studied and that this subtype fits the pharmacological profile described for mammals. It is also demonstrated that the autoradiographic interspecific differences described in previous studies are due to changes in Bmax, while KD values remain in a similar range (0.1-0.6 nM). The distribution of beta-adrenoceptors was fairly similar in the areas of the visual Wulst of all five species studied while striking differences were found in the ectostriatum, the higher centre of the tectofugal pathway. Our findings support a role for ectostriatal beta-adrenoceptors in the visual adaptation and evolution of birds.

Adrenergic beta-Agonists↗
PubMed1996

Differences in the biological stress responses of two cattle breeds to walking up to mountain pastures in the Pyrenees.

The aim of this experiment was to study the biological responses of Pirenaica and Parda Alpina cows (2-4 years old, n = 32) and their calves (2-4 months old, n = 32) to the physical exercise of climbing to mountain pastures in spring. These two breeds have a different sensitivity to stress-induced myopathy, the Pirenaica calves being highly sensitive. The animals walked 14 km with an elevation increase of 600 m, in approximately 3 h. Blood samples were obtained the day before, immediately after the move to the mountain pastures and the following day. The plasma cortisol levels in Pirenaica cows were significantly higher than in Parda Alpina cows under basal conditions, but disappeared in later samples. There were also significant differences in the hematological parameters. Under basal conditions, the red blood cell counts, packed cell volume, and hemoglobin content of blood were higher in Parda Alpina than in Pirenaica cows, but calves of both breeds did not differ. On the other hand, the calves of both breeds were more sensitive than their dams to the exercise, as shown by the large increase in white blood cell counts with a reversal of the lymphocytes:neutrophils ratio, a consequence of cortisol secretion. In calves the largest differences were observed in the muscle enzyme activity levels measured in serum (creatin kinase, lactic dehydrogenase, aspartate amino transferase and alanine amino transferase), which were always higher in the Pirenaica calves both under basal conditions and after exercise. These biological changes reflected the sensitivity of Pirenaica calves to muscular problems when they walk up to the pasture. It was concluded that genetic factors and age might play essential roles in the neuroendocrine and metabolic adaptation to this unusual physical exercise.

Aging↗
PubMed1995

Evidence that the loss of bone mass induced by GnRH agonists is not totally recovered.

There is disagreement as to whether the loss of bone mass induced by GnRH agonists is reversible. In part, the differences of opinion might be attributed to the fact that the influence of weight and seasonal changes on bone mass is often overlooked. Taking into consideration weight and seasonal changes in bone mass, total (TBBMC) and regional body bone mineral content were measured in 38 women treated with GnRH agonists for 6 months for endometriosis or leiomyomata. Measurements were made at the onset of treatment, at 6 months of treatment and at 6 months after finishing treatment. TBBMC was corrected for body weight. Body weight had increased significantly at 6 months of treatment (P = 0.0175). Regional bone mineral content showed the following: limbs, no changes; head, significantly lower at 12 months than at baseline (P = 0.0036) and at 6 months (P = 0.0343) of therapy; trunk, significantly lower at 6 months (P = 0.0002) compared to baseline, but the values at 1 year were not significantly different from either the baseline or the 6-month values; pelvis, the same pattern of change as in the trunk (P = 0.0349). TBBMC was significantly lower at 6 months of treatment (P < 0.0001) and at 1 year (P = 0.0162). TBBMC adjusted for weight experienced the same changes as unadjusted bone mineral content (P < 0.0001 and P < 0.0009 at 6 months and 1 year, respectively). Our findings indicate that the bone mass lost with GnRH treatment had not been restored 6 months after discontinuing treatment.

Adult↗
PubMed1995

[Spinal cord compression as the presenting form of non-Hodgkin's lymphoma].

Spinal cord compression as first presentation of non-Hodgkin's lymphoma (NHL) is an uncommon event. Diagnosis of NHL usually is performed on a laminectomy specimen. Spinal cord compression has been reported in 5% of patients with solid tumors. Although this clinical picture has been considered as very unusual among NHL patients, some series regarding descompresive laminectomy indicate that NHL was the underlying cause in 15% of these cases. We report two cases of patients with NHL who presented paraparesia secondary to spinal cord compression due to lymphomatous mass in the epidural region which was showed by magnetic resonance imaging. The emergency laminectomy and treatment with chemotherapy allowed the clinical recuperation of both patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1984

Testicular changes in the rat by prepuberal administration of a synthetic antiandrogen.

The testes of treated animals showed mature spermatozoa and a smaller surface of tubules. Spermatic wave shifted, showing more mitotic figures and less mature spermatozoa. Antiandrogen plus testosterone propionate (TP) and human chorionic gonadotropin (hCG) administration showed, respectively, increased and decreased prostate and testicular weights. Histological aspects of the tubules did not improve by hormonal replacement; instead, altered and multinucleated cells appeared. Testicular modifications showed that antiandrogen administration induced changes in gonadotropin secretion.

Androgen Antagonists↗
PubMed1982

Is there a cholinergic circadian rhythm throughout the oestrous cycle related to ovulation in the rat?

Rats with a 4-day oestrous cycle were given a single dose of atropine (100, 300, 500 or 700 mg/kg body wt) at 13.00 h on the days of oestrus, dioestrus 1, dioestrus 2 or pro-oestrus and were autopsied on the next expected day of oestrus. The doses of atropine (in mg/kg body wt) necessary to block ovulation during the cycle were 300 at oestrus, 100 at dioestrus 1 or 2 and 700 at pro-oestrus. A single dose of atropine (100 mg/kg) at oestrus, dioestrus 1 or dioestrus 2 was given at 09.00, 13.00, 17.00 or 21.00 h, autopsy again being performed on the next expected day of oestrus. The ability of atropine to block ovulation appeared to have a circadian rhythm, with a maximum blockade at 13.00 h on dioestrus 1 and dioestrus 2 and a minimum at 21.00 h on the same days. Hormone replacement (human chorionic gonadotrophin at oestrus, dioestrus 1 or 2, oestradiol benzoate at dioestrus 2 or progesterone at pro-oestrus) re-established normal ovulation in rats whose ovulation was blocked with atropine (100 mg/kg) on dioestrus 1 at 13.00 h. When ovulation was blocked with atropine but no hormone replacement had been given, rats ovulated 24 h after the next expected day of oestrus. Results obtained in these experiments suggest the existence of a circadian rhythm of gonadotrophin secretion throughout the oestrous cycle and a close relationship between that rhythm and the cholinergic system.

Animals↗