Subependymal Reaction Secondary to Choroid Plexus Papilloma in a Horse

Choroid plexus papilloma (CPP) is a rare, benign, intracranial neoplasm. The present report described a choroid plexus papilloma of the fourth ventricle with unusual proliferative reaction of ependymal/subependymal cells in a stallion. A single, soft neoformation, red-gray in color, with an irregular surface, resembling a cauliflower, expanding from the fourth ventricle to the cerebellar peduncles was observed. Microscopically, the neoformation was composed of a single layer of simple cuboidal to columnar epithelium with a well-vascularized papillary-arboriform pattern. Multifocal subependymal aggregates forming rosettes were observed near the mesencephalic aqueduct (MA). Glial-fibrillary-acidic-protein (GFAP) was markedly positive only in the neuropil adjacent to the proliferative areas of the MA. Ependymal/subependymal reactions secondary to CPP have never been described in equine or human neuropathology. The capabilities of ependymal cells to regenerate and eventually proliferate are controversial and unclear and, thus, require additional investigation to understand the adaptive mechanisms of this rare pathogenic condition.     

Xylogenesis of Pinus pinaster under a Mediterranean climate

Context

The knowledge on cambial activity in water-limited environments, such as the Mediterranean, is still fragmentary. Dendrochronological studies have determined that spring precipitation plays an important part in determining tree-ring width and the properties of tracheids. However, the complex relation between cambial phenology and climate is still far from understood.

Aims

We studied the influence of climate, especially water stress, on maritime pine wood formation with the aim of determining the influence of drought on cambial activity.

Methods

A plantation of maritime pine (Pinus pinaster) was selected in the west coast of Portugal, to monitor cambial activity and wood formation using anatomical observations and band dendrometers. The trees were monitored weekly over 2 years (2010 and 2011).

Results

Xylem differentiation started earlier when warmer late winter temperatures were observed. Water stress triggered an earlier stop of wood formation and also the formation of tracheids with smaller lumen area. In both years a bimodal pattern of stem radial increment was registered by band dendrometers with two periods of increment: one in spring and another in autumn. The xylem anatomy study suggests that the autumnal increment period corresponded mostly to stem rehydration, since the differentiation of new xylem cells by the cambium was not observed.

Conclusion

Maritime pine cambial activity appears to be under a double climatic control: temperature influences cambial onset and water availability growth cessation.     

How does the landscape context of occurrence data influence models of invasion risk? A comparison of independent datasets in Massachusetts,USA

The spatial distribution of non-native, invasive plants on the landscape is strongly influenced by human action. People introduce non-native species to new landscapes and regions (propagule pressure) as well as increase ecosystem invasibility through disturbance of native ecosystems. However, the relative importance of different landscape drivers of invasion may vary with landscape context (i.e., the types and amounts of surrounding land cover and land use). If so, data collected in one context may not be appropriate for predicting invasion risk across a broader landscape. To test whether independent occurrence datasets suggest similar landscape drivers of invasion, we compared landscape models based on data compiled by the Invasive Plant Atlas of New England (IPANE), which are contributed opportunistically by trained citizen scientists, to models based on Forest Stewardship plans (FSPs), which are located in privately owned and relatively undisturbed forests. We evaluated 16 landscape variables related to propagule pressure and/or disturbance for significant predictors of invasive plant presence based on presence/absence and count regression models. Presence and richness of invasive plants within FSPs was most influenced by proportion of open land and proximity to residential areas, which are both sources of propagules in forest interiors. In contrast, IPANE invasive plant presence and richness for the same area was influenced by distance to roads and streams. These results suggest that landscape drivers of invasion vary considerably depending on landscape context, and the choice of occurrence dataset will strongly influence model results.     

The relative influence of catchment and site variables on fish and macroinvertebrate richness in cerrado biome streams

Landscape and site-scale data analyses aid the interpretation of biological data and thereby help us develop more cost-effective natural resource management strategies. Our study focused on environmental influences on stream assemblages and we evaluated how three classes of environmental variables (geophysical landscape, land use and cover, and site habitat), influence fish and macroinvertebrate assemblage richness in the Brazilian Cerrado biome. We analyzed our data through use of multiple linear regression (MLR) models using the three classes of predictor variables alone and in combination. The four MLR models explained dissimilar amounts of benthic macroinvertebrate taxa richness (geophysical landscape R ² ≈ 35 %, land use and cover R ² ≈ 28 %, site habitat R ² ≈ 36 %, and combined R ² ≈ 51 %). For fish assemblages, geophysical landscape, land use and cover, site habitat, and combined models explained R ² ≈ 28 %, R ² ≈ 10 %, R ² ≈ 31 %, and R ² ≈ 47 % of the variability in fish species richness, respectively. We conclude that (1) environmental variables differed in the degree to which they explain assemblage richness, (2) the amounts of variance in assemblage richness explained by geophysical landscape and site habitat were similar, (3) the variables explained more variability in macroinvertebrate taxa richness than in fish species richness, and (4) all three classes of environmental variables studied were useful for explaining assemblage richness in Cerrado headwater streams. These results help us to understand the drivers of assemblage patterns at regional scales in tropical areas.     

Hyoscine‐N‐butylbromide premedication on cardiovascular variables of horses sedated with medetomidine

ObjectiveTo evaluate the effects of intravenous (IV) or intramuscular (IM) hyoscine premedication on physiologic variables following IV administration of medetomidine in horses.Study designRandomized, crossover experimental study.AnimalsEight healthy crossbred horses weighing 330 ± 39 kg and aged 7 ± 4 years.MethodsBaseline measurements of heart rate (HR), cardiac index (CI), respiratory rate, systemic vascular resistance (SVR), percentage of patients with second degree atrioventricular (2^oAV) block, mean arterial pressure (MAP), pH, and arterial partial pressures of carbon dioxide (PaCO₂) and oxygen (PaO₂) were obtained 5 minutes before administration of IV hyoscine (0.14 mg kg^?1; group HIV), IM hyoscine (0.3 mg kg^?1; group HIM), or an equal volume of physiologic saline IV (group C). Five minutes later, medetomidine (7.5 μg kg^?1) was administered IV and measurements were recorded at various time points for 130 minutes.ResultsMedetomidine induced bradycardia, 2^oAV blocks and increased SVR immediately after administration, without significant changes in CI or MAP in C. Hyoscine administration induced tachycardia and hypertension, and decreased the percentage of 2^oAV blocks induced by medetomidine. Peak HR and MAP were higher in HIV than HIM at 88 ± 18 beats minute^?1 and 241 ± 37 mmHg versus 65 ± 16 beats minute^?1 and 192 ± 38 mmHg, respectively. CI was increased significantly in HIV (p ≤ 0.05). Respiratory rate decreased significantly in all groups during the recording period. pH, PaCO₂ and PaO₂ were not significantly changed by administration of medetomidine with or without hyoscine.Conclusion and clinical relevanceHyoscine administered IV or IM before medetomidine in horses resulted in tachycardia and hypertension under the conditions of this study. The significance of these changes, and responses to other dose rates, requires further investigation.     

Interaction of parasitism and nutrition and their effects on production and clinical parameters in goats.

Weaned wether goats (n = 144) approximately 6 months of age were placed in a 2 x 3 factorial design experiment for 5 months to test the main effects and interaction of two levels of nutrition (growth + maintenance, NUT1; twice growth + maintenance, NUT2) and three levels of Haemonchus contortus burden (0, 500 and 2000 larvae administered every 2 weeks: W0, W500 W2000, respectively) on weight, feed intake, level of infection and packed cell volume (PCV). The rationale for the experimental design was based on the lack of information concerning the interaction between nutritional status and worm burden. Results indicated significant effects of worm burden levels on PCV, faecal egg contents (eggs per gram of feces (EPG)), actual worm numbers, feed intake and efficiency of feed utilization. Nutrition x worm burden interactions were also significant for PCV and EPG. However, the differences detected for PCV and actual worm numbers did not translate into large or consistent differences in body weight. Goats on NUT2, after an initial period, showed little difference in body weight, irrespective of worm burden. Within the NUT1 level, W0 kids weighed more than W500 or W2000 kids throughout the study. Although not statistically significant, this constitutes a trend towards an interaction between nutrition and worm burden. In both nutrition levels, there were no body weight differences between W500 and W2000 until the last 14 days. Feed intake was depressed in the first 3 months of the experiment for infected animals, but was subsequently followed by a compensatory reaction. Lower establishment rates, based on actual worm counts, were observed for the higher infection level, but in both infection levels establishment rates tended to decrease with time. Nutrition was found to be more important to counteract the consequences of a parasitic infection than to counteract the establishment of that same infection.     

Effects of remifentanil infusion regimens on cardiovascular function and responses to noxious stimulation in propofol-anesthetized cats

OBJECTIVE: To evaluate the effects of 2 remifentanil infusion regimens on cardiovascular function and responses to nociceptive stimulation in propofol-anesthetized cats. ANIMALS: 8 adult cats. PROCEDURES: On 2 occasions, cats received acepromazine followed by propofol (6 mg/kg then 0.3 mg/kg/min, i.v.) and a constant rate infusion (CRI) of remifentanil (0.2 or 0.3 microg/kg/ min, i.v.) for 90 minutes and underwent mechanical ventilation (phase I). After recording physiologic variables, an electrical stimulus (50 V; 50 Hz; 10 milliseconds) was applied to a forelimb to assess motor responses to nociceptive stimulation. After an interval (> or = 10 days), the same cats were anesthetized via administration of acepromazine and a similar infusion regimen of propofol; the remifentanil infusion rate adjustments that were required to inhibit cardiovascular responses to ovariohysterectomy were recorded (phase II). RESULTS: In phase I, heart rate and arterial pressure did not differ between remifentanil-treated groups. From 30 to 90 minutes, cats receiving 0.3 microg of remifentanil/kg/min had no response to noxious stimulation. Purposeful movement was detected more frequently in cats receiving 0.2 microg of remifentanil/kg/min. In phase II, the highest dosage (mean +/- SEM) of remifentanil that prevented cardiovascular responses was 0.23 +/- 0.01 microg/kg/min. For all experiments, mean time from infusion cessation until standing ranged from 115 to 140 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: Although the lower infusion rate of remifentanil allowed ovariohysterectomy to be performed, a CRI of 0.3 microg/kg/min was necessary to prevent motor response to electrical stimulation in propofol-anesthetized cats. Recovery from anesthesia was prolonged with this technique.     

Assessment of genetic relatedness of the genera Ananas and Pseudananas confirmed by RAPD markers

Genetic relationships among 18 accessions, including 16 of Ananas and two of Pseudananas, were investigated using RAPD molecular markers. The procedure for DNA extraction was adapted from the method of Dellaporta et al. (1983) where an incubation in proteinase K and a purification step were included. From the total of 148 markers scored,132 (89.2%) were polymorphic. The similarity matrix was used for cluster analysis. The phenogram developed from the RAPD bands showed that for most of the cases, the accessions within a species grouped together. Nevertheless, a moderate infraspecific genetic variation was observed. For example, DNA data grouped all A. comosus accessions with a mean similarity coefficient of 0.85. Comparable results were obtained with all other species investigated. The highest genetic divergence was found withinA. lucidus where the mean similarity coefficient among accessions was0.75. A similar level of genetic polymorphism was observed among species,therefore, a definition about which species were involved in the constitution of A. comosus genotypes was not possible. These results agree with the breeders standpoint suggesting that all Ananas species belong to the primary gene pool of pineapple. This revised version was published online in July 2006 with corrections to the Cover Date.     

Meiotic behavior of passion fruit somatic hybrids, Passiflora edulis f. flavicarpa Degener + P. amethystina Mikan

Somatic hybrids (SH) obtained by protoplast fusion were investigated for meiotic behavior in order to determine their possible use in breeding programs. Flower buds from four genotypes of SH between P. edulis f. flavicarpa (E) and the wild species P. amethystina (Am) denoted SH (E + Am) # 12, # 13, # 28 and # 35 were collected and the microsporocytes analysed. Meiotic phases showed the presence of abnormalities such as univalents, bivalents and quadrivalents, laggard chromosomes and anaphase bridges. At least 14 bivalents were observed in most of the cells of the hybrid plants. The percentage of cells with quadrivalents ranged from 73.3 in (E + Am) # 13 to 93.3 in (E + Am) # 28 and # 35. Analysis of pollen viability (V) indicated V = 88.23% for # 12, V = 83.86% for # 13, V = 84.20% for # 28, and V = 72.90% for # 35, and fruit development was observed. The high pollen viability, together with the multivalent pairing observed in the four somatic hybrids indicates that these materials can be used for the genetic improvement of yellow passion fruits aiming at introgressions of genes for resistance to diseases and pests. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effect of Ogura male-sterile cytoplasm on the performance of cabbage hybrid variety. II. Commercial characteristics

Summary The main constraint of using Ogura male-sterile cytoplasm in Brassica is the induction of leaf yellowing at low temperature and the low seed set. But whether or not the cytoplasm can disturb the general commerical performance of the plants is not well-known. Therefore, this work was carried out with the purpose of evaluating Ogura cytoplasmic male-sterile cabbage hybrids and compare them to genomic similar male-fertile ones and to the most popular cabbage hybrid cultivated in Brazil. Harvest data showed an effect of the cytoplasm on reducing plant and head weight, core length and head length and width, although not altering heading index, shape and core indexes, nor head compactness. On the other hand, it was observed also that a careful selection of the parental lineages can produce male-sterile hybrids as good as their male-fertile analogues. All the evaluated hybrids were similar or better than the check for the characteristics under study.Abbreviations dat - days after transplanting - CNPH - National Center for Vegetable Crops Research