Using visual modelling to study the evolution of lizard coloration: sexual selection drives the evolution of sexual dichromatism in lacertids.

Sexual selection has been invoked as a major force in the evolution of secondary sexual traits, including sexually dimorphic colourations. For example, previous studies have shown that display complexity and elaborate ornamentation in lizards are associated with variables that reflect the intensity of intrasexual selection. However, these studies have relied on techniques of colour analysis based on human--rather than lizard--visual perception. Here, we use reflectance spectrophotometry and visual modelling to quantify sexual dichromatism considering the overall colour patterns of lacertids, a lizard clade in which visual signalling has traditionally been underrated. These objective methods of colour analysis reveal a large, previously unreported, degree of sexual dichromatism in lacertids. Using a comparative phylogenetic approach, we further demonstrate that sexual dichromatism is positively associated with body size dimorphism (an index of intrasexual selection), suggesting that conspicuous coloration in male lacertids has evolved to improve opponent assessment under conditions of intense male-male competition. Our findings provide the first evidence for the covariation of sexual dichromatism and sexual size dimorphism in lacertids and suggest that the prevalent role of intrasexual selection in the evolution of ornamental coloration is not restricted to the iguanian lineage, but rather may be a general trend common to many diurnal lizards.

Myoepithelial cell layer integrity in canine mammary carcinoma.

The aim of this study was to determine whether the myoepithelial (ME) cell marker calponin could be used to analyze the integrity of the ME cell layer as a means of identifying canine mammary carcinoma in situ. Tissue from 74 canine mammary lesions was evaluated (two dysplasia, eight benign tumours and 64 carcinomas including one carcinoma in situ). The 63 carcinomas included examples of histological grade 1 (n=32), grade 2 (n=23) and grade 3 (n=8). Expression of calponin was determined by immunohistochemistry. The percentage of proliferating cells surrounded by a single layer of calponin-positive cells formed the basis of classification as type I (≥ 90%), type II (70-90%) and type III (≤ 70%). Expression of Ki67 was used to determine the proliferation index (PI). The malignant tumours comprised of an approximately equal mixture of type I, II and III lesions. The two examples of dysplasia, the carcinoma in situ and two thirds of the benign tumours were classified as type I lesions. Some overlap in the level of calponin expression was observed between benign and malignant tumours. Positive correlations between the degree of calponin expression and the type of lesion (i.e. benign versus malignant; R=+0.3, P=0.08) and the histological grade of malignancy (R=+0.54, P=0.000001) were found. A negative correlation between the degree of calponin expression and PI (R=+0.027, P=0.016) was found. The ME cell marker calponin may be used as an aid in the identification of canine carcinoma in situ, but the study of the ME cell layer integrity is not definitive for the diagnosis of malignancy in canine mammary tumours.

Quantitative study of Leydig cell populations in mice exposed to low doses of cadmium.

Leydig cell morphological changes were evaluated using morphometric and stereological methods in male mice exposed to low doses of cadmium. A possible reversibility of the changes after cadmium withdrawal was also considered. Nuclear morphological parameters and stereological densities of the Leydig cell population were lower in the cadmium-exposed groups than in the control. The withdrawal of cadmium did not lead to any significant recovery of the morphological parameters. Nevertheless, numerical density increased significantly in the withdrawn groups, suggesting that the hyperplasia of interstitial cells could try to relieve morphological damage after cadmium withdrawal.

Endogenous lipid pneumonia in rats after subacute exposure to CdCl2.

The objective of this report was to study lung cellular lesions in Wistar rats after subacute oral exposition to CdCl(2). The experimental groups were exposed to CdCl(2), through their drinking water in a concentration of 1 g/L, continuously for a period of 9 days. Histologically, all the exposed animals showed the incidence of interstitial pneumonia; hyperplasia of type II pneumocytes and Clara cells; the presence of foamy macrophages; and lesions linked to the existence of endogenous lipid pneumonia. Endogenous lipid pneumonia after CdCl(2) exposure has not been previously described; and in its pathogenesis, hyperplasia of type II pneumocytes and Clara cells activation could play an important role.

Multigenerational study of the hepatic effects exerted by the consumption of nonylphenol- and 4-octylphenol-contaminated drinking water in Sprague-Dawley rats.

Our multigenerational study evaluates the hepatic effects of the xenoestrogens nonylphenol (NP), and 4-octylphenol (4OP) on male and female rats when they are exposed uninterruptedly, from conception to adult age, to tap water containing 25ppm of NP or 4OP. Our results showed that these compounds did not induce any change in liver/body weight ratio (relative liver weight, RLW). In the morphological analysis we did not find evident signs of cytotoxicity. The most relevant findings were the presence of both an increase in the apoptotic index and in the percentage of binuclear hepatocytes in livers from exposed animals. Additionally, our study revealed the presence of hepatocellular glycogenosis (mainly in 4OP-exposed rats): the type of glycogen accumulated was in aggregates (gamma-glycogen), a non-functional form of glycogen. This study demonstrates that, at levels close to those described in the environment, NP and 4OP are capable of inducing a number of hepatic effects, potentially related with adaptive, and/or metabolic alterations of liver tissue.

Purkinje cell apoptosis in arabian horses with cerebellar abiotrophy.

Purkinje cerebellar cells were studied in three Arabian horses aged between 6 and 8 months with clinical disorders in their movements, tremors and ataxia; the occurrence of apoptosis in this cell population was investigated by the (terminal deoxynucleotidyl transferase biotin-dUTP nick-end labelling (TUNEL) method. Both optical and electron microscopical images showed a scant number of Purkinje cells, most of them with morphological features of apoptosis such as condensation of the nucleus and cytoplasm as well as segregation and fragmentation of the nucleus into apoptotic bodies. The TUNEL technique revealed a substantial number (65%) of positive immunoreactive Purkinje cells.

Structural and ultrastructural study of the intracranial portion of the oculomotor, trochlear and abducent nerves in dog.

The right intracranial portion of the oculomotor, trochlear and abducent nerves were removed from six adult German shepherd dogs and analysed by light and electron microscopy. In all cases the nerve sectional area was calculated. Unmyelinated and myelinated fibres were analysed and number, diameter and cross-sectional area were calculated. In myelinated fibres, also calculated were the corresponding axon area and diameter, and myelin sheath thickness. The mean number of myelinated fibres was 8543.50 +/- 1231.85 being the unmyelinated 1402 +/- 241.58 in the oculomotor nerve; 1509 +/- 223.17 and 287.67 +/- 72.28 in the trochlear nerve and 2473.00 +/- 211.41 and 231.25 +/- 92.67 respectively in the abducent. The mean diameter was 10.23 +/- 0.68 microm in myelinated and 0.43 +/- 0.21 for unmyelinated in oculomotor nerve, 10.53 +/- 0.55 microm and 0.33 +/- 0.04 for the trochlear, and 10.45 +/- 1.27 microm and 0.47 +/- 0.09 in the abducent nerve respectively. This study reveals that oculomotor, trochlear and abducent nerves of the dog show structural and ultra-structural features similar to the same nerves in other species.

Acid and alkaline phosphatase activities and pathological changes induced in Tilapia fish (Oreochromis sp.) exposed subchronically to microcystins from toxic cyanobacterial blooms under laboratory conditions.

The effects of microcystins (MCs) from cyanobacterial cells on the enzymatic activities of acid and alkaline phosphatases (ACP and ALP) from liver, kidney and gill tissues, and the histopathological changes in freshwater Tilapia fish (Oreochromis sp.) were investigated under laboratory conditions. Fish were exposed to cyanobacterial cells (60.0 microg MC-LR/fish per day) through their diet at different exposure times (14 and 21 days). The cells were fed to the fish in two types of oral administration: mixed with a commercial fish food or crushed into a commercial fish food so that the toxins were released. ACP and ALP activities changed in response to MCs in a time-dependent manner, and these changes were more prominent in liver and kidney. The way the MCs were administered had no influence on the biochemical parameters. Similarly, the most severe histopathological changes were observed in the same two organs, although the gills and intestines were also affected. The parenchymal architecture of the liver was dissolved, and round hepatocytes with the appearance of pyknotic nuclei were detected. Kidney lesions consisted of the dilation of Bowman's space and necrotic epithelial cells with pyknotic nuclei in the tubules. These findings suggest that low and repeated doses of MC-LR from cyanobacterial cells induce toxicity in tilapia fish although no adverse effects were detected.

Impact of local guidelines and an integrated dispensing system on antibiotic prophylaxis quality in a surgical centre.

Surgical antibiotic prophylaxis is effective in preventing postoperative wound infections. Guidelines are designed to optimize antimicrobial use in this setting. The aim of this study was to assess antibiotic use in surgical prophylaxis in a surgical hospital before and after the implementation of both local antibiotic prophylaxis guidelines and a specific medication set for various surgical procedures. The appropriateness of surgical antibiotic prophylaxis increased from 50.9% in the pre-implementation stage to 94.9% in the postimplementation stage (P<0.001). The implementation of a multidisciplinary protocol and design of medication sets helped to improve the practice of surgical antibiotic prophylaxis.

Análisis morfométrico de las fibras nerviosas del nervio abducente del perro / Morphometric analysis of the nerve fibers of the abducent nerve in dog

Para nuestro estudio hemos analizado la porción intracraneal de los nervios abducentes derechos extraídosde seis perros adultos, de raza pastor alemán. Los nervios fueron analizados con microscopia óptica y microscopiaelectrónica. En todos los nervios hemos calculado su área y analizado las fi bras mielínicas y amielínicas.En ambos tipos de fibras hemos determinado su número, diámetro y área, así como el área y el diámetro delaxón correspondiente y el grosor de la vaina de mielina en las fibras mielínicas. El número medio de fibras esde 2473,00 ± 211,41 mielínicas y 231,25 ± 92,67 amielínicas. El diámetro medio fibrilar fue de 10,45 ± 1,27 mm para las fibras mielínicas y 0,47 ± 0,09 mm para las amielínicas. Nuestro estudio sobre el nervio abducentemuestra que este nervio, en el perro, presenta características estructurales y ultraestructurales semejantes a la de otros nervios y otras especies

The intracranial portion of the abducent nerve was studied in dogs. The nerves were dissected from sixadult German shepherd dogs. The nerves were analysed by both light and electron microscopy. In all nerveswe calculated their area and analysed both myelinated and unmyelinated fibers. In both we determined theirnumber, diameter and area; also the area and diameter of the correspondent axon, and the thickness of the myelinsheath. The mean number of fibers was 2473.00±211.41 for myelinated and 231.25±92.67 for unmyelinatedones. The average fiber diameter was 10.45±1.27 mm for myelinated and 0.47±0.09 mm for unmyelinated. Thisstudy on the abducent nerve demonstrated that dogs shows structural and ultrastructural characteristics similartothose of another nerves and other species

Estudio estructural y ultraestructural de la porción intracraneal del nervio troclear del perro / Structural and ultrastructural study the intracranial portion of the trochlear nerve in the dog

En el presente trabajo se han extraído, de seis perros adultos, de 40-50 kilogramos de peso, los nervios trocleares derechos en su porción intracraneal. Los nervios fueron analizados con microscopia óptica y microscopia electrónica. Hay que destacar la presencia de fibras no mielinizadas en todos los nervios analizados. De las fibras mielinizadas hemos determinado su número, diámetro, área y densidad , así como el área y el diámetro del axón correspondiente y el grosor de la vaina de mielina. El número medio de fibras mielínicas contabilizadas fue de 1482,25. El histograma de frecuencias relativo al grosor de la vaina de mielina y al tamaño fibrilar muestran una distribución bimodal, siendo 10,8 μm el valor medio de discriminación de las dos poblaciones fibrilares. Se aprecia una proporción similar de fibras grandes (47,45%) y pequeñas (52,55%). La población de fibras pequeñas presentan un tamaño medio de 6,44 μm y ocupan un 12,10% de la superficie total del nervio, por el contrario las fibras grandes, con un tamaño medio de 15,34 μm ocupan el 60,20% del nervio (AU)

In the present investigation, the right intracranial portion of the trochlear nerves was removed from six adult dogs weighing 40-50 kg and analyzed by light and electron microscopy. A significant number of unmyelinated fibers were observed in the analyzed nerves. Number, diameter, area and density of myelinated fibers were determined as were corresponding axon area and diameter and myelin sheath thickness. Myelinated fibers count produced a mean of 1482,25. Frequency histograms of myelin sheath thickness and fiber size show a bimodal distribution being 10,8 μm the mean value of discrimination of the two populations. A similar proportion of large (47,45%) and small fibers (52,55%) is appraised. The small fibers population was present in a size mean of 6,44 μm and occupies a 12,10% of the total surface of the nerve, on the contrary the large fibers, with size mean of 15,34 μm ocupy a 60,20% of the nerve (AU)

Testicular damage from anabolic treatments with the beta(2)-adrenergic agonist clenbuterol in pigs: a light and electron microscope study.

The morphological consequences of anabolic clenbuterol treatment on the testicular parenchyma were investigated in 30 pigs at morphological and ultrastructural levels. Clenbuterol was given with food (1 ppm). In the first group (n=10), treatment was maintained until slaughter (experimental period 3 months). In the second group (n=10), clenbuterol was withdrawn 2 weeks before slaughter (experimental period 2.5 months). A third group (n=10) of pigs not fed with clenbuterol served as controls. Animals were slaughtered at 9 months of age and samples of testicular parenchyma were collected for light and electron microscope studies. In the clenbuterol-treated groups, the interstitial cells showed a considerable increase in the organelles involved in testosterone production, with an increased development of the mitochondria, smooth endoplasmic reticulum, Golgi apparatus and lipid droplets compared to the control group. The seminal epithelium displayed many lipid vacuoles and evident signs of tubular involution, such as degenerating and multinucleate germ cells. Sertoli cells gave evidence of metabolic alterations such as large lipid deposits and cytolysosomes.

Effects of anabolic implants of oestradiol alone or in combination with trenbolone acetate on the ultrastructure of mammary glands in female lambs regarding their interference in prolactin secretion.

The side-effects of anabolic steroid implants on mammary gland ultrastructure were evaluated in female lambs treated with oestradiol (n = 10) and with oestradiol plus trenbolone acetate (n = 10). Ten non-implanted lambs were used as controls. Apart from the ultrastructural study of the mammary gland, an assessment of the prolactin pituitary cell population was carried out by immunological methods. Our results showed that oestrogenic implants exert stimulating effects on mammary gland development, both by activating the synthesis process at mammary gland cell levels and by increasing prolactin pituitary production. Nevertheless, there was no evidence of secretory products in the lumen of the gland. Implants containing trenbolone acetate counteracted the mammary stimulus of oestrogens showing ultrastructural images of cell autolysis and necrosis.

Changes due to age in the kinematics of trotting Andalusian foals.

The purpose of this study was to evaluate the effect of growth on biokinematic characteristics at the trot in a group of 9 Andalusian foals from age 12 to 36 months in order to identify which stride variables change or remain invariable. Biokinematic analysis was performed by using a computer-assisted videography system (25 Hz frame rate). An increase in stride length as well as the fore- and hindlimb stride duration was found. A tendency to increase flexion of the shoulder, elbow and carpal joints was observed while the forelimb fetlock increased its maximal extension. In the hindlimb, most of the differences were exhibited by the hip and stifle joints, which showed a tendency to a lesser flexion with age. However, at landing the extension was bigger. The hindlimb fetlock extended more in older foals, whereas flexion decreased. Significant differences in the maximal extension and flexion instants in the forelimb joints were not detected (except in the elbow joint). The same was found in the angular range of motion (ARM) of the scapula inclination and the shoulder and forelimb fetlock joints. Differences in retraction-protraction angles in both the fore- and hindlimbs were very slight, and ARM values for these parameters were similar in all age groups. It can be concluded that Andalusian horses modified their locomotor pattern at the trot between age 12 and 36 months, particularly up to 24 months, by increasing stride length as well as shoulder, elbow and carpus flexion, while hip and stifle flexion decreased and hindlimb joints were more extended during the stance phase. One of the most striking features was that maximal retraction and protraction angles did not change in foals age 12-36 months in either fore- or hindlimbs. These results could be useful for the prediction of some kinematic parameters of mature horses from data obtained at younger ages.

Stereological study of normal and apoptotic cell populations in the adrenal gland in calves.

Morphometrical features of the adrenal gland in calves were assessed using stereological methods for normal and apoptotic cells. Adrenal glands were obtained from calves (n = 16) after they were slaughtered in a commercial abattoir. Quantitative data of nuclear size showed the highest values in the noradrenaline-storing region for all parameters, whereas the nuclei of the zona fasciculata were significantly larger than those of the other cortical regions. Data of nuclear size and shape of apoptotic cells reflected their morphometrical features; as expected, a notable decrease in the nuclear size and a more irregular shape were found in apoptosis with respect to the normal nuclei in all adrenal regions. The volume fraction data supplied the percentage of the adrenal gland occupied by each histological zone, highlighting the zona fasciculata as being the most extensive one. A significant increase in V(V)(nucl/tis), S(V)(nucl/tis), and Nv(nucl/tis) was observed in cortical regions with respect to the medullar regions. A comparison between normal and apoptotic nuclei indicated a highly significant decrease in V(V)(nucl/tis), S(V)(nucl/tis), and Nv(nucl/tis) for the apoptotic nuclei in all the adrenal zones. The apoptotic nuclei figures found in all the adrenal regions suggest that a process of cell renovation occurred in all the zones, although the higher number of apoptosis in zona reticularis is in agreement with previous results that have pointed out this zone as being a cell senescence region. The results of discriminant analyses gave the parameter required and the percentage of correct classifications for discriminating between normal nuclei, between apoptotic nuclei and between normal and apoptotic nuclei.

Simple and rapid determination of nevirapine in human serum by reversed-phase high-performance liquid chromatography.

Nevirapine is an antiretroviral agent belonging to the class of non-nucleoside reverse transcriptase inhibitors. We describe a fast, simple isocratic reversed-phase high-performance liquid chromatography method with a 30-mm long column for assaying nevirapine in human serum. After deproteinization of 200 microl serum samples with 50% trichloroacetic acid, the supernatant was injected into a reversed-phase C18 column, using 10 mM phosphate buffer (pH 5)-acetonitrile (82:18, v/v) as the mobile phase. Peak detection was performed at 240 nm. Nevirapine retention time was 2 min. The method was validated over 0.1-10 microg/ml and the assay was linear over this concentration range (r2>0.998). Within- and between-day precisions were less than 5.4%. The lower limit of quantification was 0.1 microg/ml. Nevirapine in human serum samples was stable for 2 days at 20-25 degrees C, 15 days at 4 degrees C and 3 months at -20 degrees C.

Morphological and quantitative study of the Leydig cells of pigs fed with anabolic doses of clenbuterol.

The effects of clenbuterol administered at anabolic doses on the testicular interstitium were studied in 30 pigs allocated to three experimental groups. The diet of two groups was supplemented with clenbuterol (Clb) (1 ppm), but whereas in the Clb+ group the treatment was given until slaughter (treatment period: 3 months), in the Clb- group the clenbuterol was withdrawn 2 weeks before slaughter (treatment period: 2-5 months); in the control group, the pigs were fed without clenbuterol. For histological procedures, a fractional sampling scheme was applied and routine techniques for light and transmission electron microscopy were used. The results of subjective morphology and morphometrics showed slight differences between the treated and the control groups. Conversely, the stereological results identified a prominent hyperplasia of the Leydig cells and ultrastructural analysis of these cells revealed a conspicuous increase in the organelles related to testosterone production, suggesting a functional activation of the interstitial cells in response to the clenbuterol treatment.