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Large Animals (large + animals)
Selected AbstractsThe use of clinical findings in the identification of equine peritonitis cases that respond favorably to medical therapyJOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 4 2007DACVECC, DACVS, Louise L. Southwood BVSc Abstract Objective: To compare clinical findings in horses/foals with peritonitis that: (1) had no concurrent (NCA) versus a concurrent abnormality found during hospitalization, (2) survived to discharge versus did not survive to discharge, and (3) survived to discharge without surgery versus did not survive to discharge without surgery. Design: Retrospective study. Setting: George D. Widener Hospital for Large Animals at New Bolton Center. Animals: Horses/foals admitted between 1992 and 2002 with a diagnosis of peritonitis. A diagnosis of peritonitis within 4 days of presentation and peritoneal fluid nucleated cell count >10,000/,L were required for study inclusion. Horses/foals were excluded if the peritonitis was secondary to gastrointestinal or reproductive tract perforation, a complication of exploratory celiotomy, or if peritonitis was not diagnosed until surgery or necropsy. Interventions: None. Measurements and main results: Information obtained from the medical records included clinical findings at presentation and during the initial 4 days of hospitalization. Outcome was defined as: (1) NCA (yes/no), (2) survived to discharge (yes/no), and (3) survived to discharge without surgery (yes/no). Forty-two percent (23/55) of horses/foals had NCA; 78% (43/55) survived to discharge, and 68% (36/55) survived to discharge without surgery. Horses/foals with peritonitis that had any one of the following clinical findings were likely to survive to discharge without surgery: no signs of abdominal pain, normal/improved rectal temperature, normal/improved intestinal borborygmi, normal fecal production, no abnormal findings on abdominal palpation per rectum, no nasogastric reflux, or yellow/orange peritoneal fluid. Conclusion: Clinical findings can be used to identify equine peritonitis cases that will respond favorably to medical therapy. [source] Rotating Frame for the In-situ Fixation of Large AnimalsANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2009F.-V. Salomon Summary The frame for the in-situ fixation of large animals can be rotated around its longtitudinal axis. Thereby the fixing procedure is improved and the anatomical preparation is easier. [source] Teaching of Anatomy of Genital Organs in the Large AnimalsANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005G. M. Constantinescu At the University of Missouri-Columbia, USA, teaching the anatomy of genital organs in large (and in small) animals is clinically oriented. In the male horse, ox, and pig, the descriptive anatomy of the structures is taught in that order as they are listed in Nomina Anatomica Veterinaria. Clinical correlates are immediately mentioned in relation to each of the following structures. The testicle, epididymis, ductus deferens, spermatic cord, and tunics of spermatic cord and testis are correlated to the castration, criptorchidism, ectopic testicles, and inguinal herniae, as well as to the landmarks and approaches to different clinical techniques. The penis and male urethra are correlated to the prolapse of the prepuce, ulcerative posthitis, balanitis, penile deviation, penischisis, persistent penile frenulum, short retractor penis muscle, catheterization of the urethra, the contagious equine metritis (CEM), etc. In the female horse, ox and pig, following the similar order as in the male species, the ovary and the salpinx are correlated to the diagnosis of pregnancy by rectal exploration, ovarian hypoplasia, ectopic pregnancy, and ovariectomy. The uterus is correlated to the different aspects of metritis and endometritis, to the retained placenta, pyometra, uterine torsion, uterine prolapse and eversion, Caesarian section, diagnosis of pregnancy and different stages of oestrus by rectal exploration, double external ostium of the cervix, distocia, and the assessment of possible difficulties in the birth process. The vagina and vestibulum vaginae are correlated to the gaertneritis, vaginal and cervical prolapse, vaginitis, catheterization of the urinary bladder, and pelvimetry. The vulva and clitoris are correlated to vulvitis, balanitis, distocia, episiotomy, and transmissible genital diseases. Different kinds of udder diseases (mastitis) are based on the thorough knowledge of the anatomy of the udder including the blood and nerve supply and the lymphatic system. The two techniques of epidural anesthesia (Magda and Farquharson in ruminants) and subsacral anaesthesia (Popescu) for diagnosis and treatment purposes are explained in detail. [source] The Plight of Large Animals in Tropical Forests and the Consequences for Plant RegenerationBIOTROPICA, Issue 3 2007S. Joseph Wright ABSTRACT We introduce a special section that addresses the bushmeat or wild meat crisis, its direct impact on game species, and its indirect impact on plants in tropical forests. RESUMEN Introducimos una sección especial que trata la crisis de la carne de animales salvajes, su impacto directo sobre las especies cazadas y su impacto indirecto sobre las plantas en los bosques tropicales. [source] Naked Mole-Rat is Sensitive to Social Hierarchy Encoded in Antiphonal VocalizationETHOLOGY, Issue 9 2009Shigeto Yosida The maintenance of social relationships is critical for group-dwelling species. Social animals often exhibit behaviors such as antiphonal vocalizations that reduce conflict and maintain affiliations. Naked mole-rats (Heterocephalus glaber) have a complex hierarchical society comparable to that of bees and ants. They are also known for their extensive vocal repertoire, which may have evolved in the absence of visual cues. The most frequent vocalization used by naked mole-rats is the soft chirp (SC). It has an antiphonal nature and may function in rank identification and in maintaining affiliations. Relative body weight differences, which are directly related to social rank, are positively correlated with SC emission rates. SCs are elicited from either physical touch or the SC of another conspecific, and other cues might contribute to SC utterance. In the current study, we examined whether an SC alone was able to elicit SC responses. Specifically, we presented artificial SC-like sounds and determined whether the response rate was modulated by the acoustic properties of the stimulus. An analysis of response latency revealed that animals responded to the audio stimuli, and a single audio stimulus could elicit responses from two animals. Thus, antiphony in naked mole-rats may occur among three or more animals. We also found that animals were able to discriminate the acoustic properties of the stimulus and responded more frequently to audio stimuli resembling SCs from large animals than to those resembling SCs from small animals. Therefore, naked mole-rats may be able to judge social relationships (dominant or subordinate) based solely on SCs. The constraints of subterranean habitats and increased social complexity may have led to the evolution of this communication system. [source] Risk Assessment and Withdrawal Behavior by Two Species of Aposematic Poison Frogs, Dendrobates auratus and Oophaga pumilio, on Forest TrailsETHOLOGY, Issue 4 2009William E. Cooper Jr Many chemically defended prey advertize toxicity to predators by aposematic coloration. When aposematic prey are approached, they often move slowly or not at all, allowing predators to evaluate their unprofitability. Poison frogs (Dendrobatidae) are toxic, aposematically colored, forage openly and diurnally, and are much easier to capture than many palatable frogs. Although protected against diverse predators, they are sometimes attacked and are subjected to injury by large animals without predatory intent. We predicted that they have limited escape behavior, but retain ability to assess and respond to risk. When we approached Dendrobates auratus and Oophaga pumilio on forest trails, both species hopped by the shortest route to the nearer forest edge and stopped there. When approached, D. auratus moved after shorter latency at an angle closer to perpendicular to the forest edge, were more likely to leave the trail, and left the trail sooner with fewer changes in direction after moving a shorter distance than when not approached. In agreement with predictions of optimal escape theory based on risk, flight initiation distance by D. auratus was greater when approached directly than indirectly and rapidly than slowly, and was greater when frogs were in the open than partially concealed. Frogs neither attempted rapid escape nor entered refuges. Both species hopped leisurely and remained visible after stopping. They exhibit the diminished escape behavior of aposematic prey, yet retain the capacity to assess risk and adjust behavior accordingly. Their behavior demonstrates continued need for escape behavior by highly toxic aposematic prey. [source] PERSPECTIVE: THE SIZE-COMPLEXITY RULEEVOLUTION, Issue 9 2004J. T. Bonner Abstract It is widely accepted that bigger entities have a greater division of labor than smaller ones and this is reflected in the fact that larger multicellular organisms have a corresponding increase in the number of their cell types. This rule is examined in some detail from very small organisms to large animals, and plants, and societies. Compared to other size-related rules, the size-complexity rule is relatively rough and approximate, yet clearly it holds throughout the whole range of living organisms, as well as for societies. The relationship between size and complexity is analyzed by examining the effects of size increase and decrease: size increase requires an increase in complexity, whereas size decrease permits, and sometimes requires, a decrease in complexity. Conversely, an increase or decrease in complexity permits, but does not require changes in size. An especially compelling argument for the close relation between size and complexity can be found in size quorum sensing in very small multicellular organisms. [source] On the measurement of growth with applications to the modelling and analysis of plant growthFUNCTIONAL ECOLOGY, Issue 2 2000Roderick M. L. Abstract 1.,In this paper, a theoretical framework for the analysis of growth is described. Growth is equated with change in volume (V) and the growth rate is given by the equation; dV/dt = (dm/dt)(1/,) , (d,/dt)(m/,2) where m is the mass and , the density. The volume is inclusive of internal air spaces. 2.,The second term of the growth equation (see above) can be ignored if density is constant over time. Data for humans (and presumably other large animals) show that while composition changes over time, the density is approximately constant at about that of water. In that case, the growth rate can be estimated from measures of the rate of change of mass. However, the density of plants is variable (c. 0·4,1·2 g cm,3) and measures of mass and density are necessary to analyse plant growth. 3.,To use the theory as the basis of plant growth models, it is necessary to develop simple methods for estimating the surface area of roots, stems and leaves assuming that the mass and volume are known. A literature review found that the surface area to volume ratios of leaves and roots generally increase with the mass concentration of water. Theoretical arguments are used to predict that in woody stems, the situation should be reversed such that the surface area to volume ratio increases with the mass concentration of dry matter. Those relationships should be very useful in the development of plant growth models. 4.,Measures of plant dry mass and estimates of the rate of change in dry mass are shown to be very difficult to interpret because of differences in the mass concentration of dry matter between individuals and over time. 5.,It is concluded that measures of mass and density will be necessary before plant growth analysis can achieve its full potential. A framework for extending the theory to include the forces necessary for growth to occur is described. [source] Predator size, prey size and threshold food densities of diving ducks: does a common prey base support fewer large animals?JOURNAL OF ANIMAL ECOLOGY, Issue 5 2009Samantha E. Richman Summary 1. Allometry predicts that a given habitat area or common prey biomass supports fewer numbers of larger than smaller predators; however, birds from related taxa or the same feeding guild often deviate from this pattern. In particular, foraging costs of birds may differ among locomotor modes, while intake rates vary with accessibility, handling times and energy content of different-sized prey. Such mechanisms might affect threshold prey densities needed for energy balance, and thus relative numbers of different-sized predators in habitats with varying prey patches. 2. We compared the foraging profitability (energy gain minus cost) of two diving ducks: smaller lesser scaup (Aythya affinis, 450,1090 g) and larger white-winged scoters (Melanitta fusca, 950,1800 g). Calculations were based on past measurements of dive costs with respirometry, and of intake rates of a common bivalve prey ranging in size, energy content and burial depth in sediments. 3. For scaup feeding on small prey <12 mm long, all clams buried deeper than 5 cm were unprofitable at realistic prey densities. For clams buried in the top 5 cm, the profitability threshold decreased from 216 to 34 clams m,2 as energy content increased from 50 to 300 J clam,1. 4. For larger scoters feeding on larger prey 18,24 mm long, foraging was profitable for clams buried deeper than 5 cm, with a threshold density of 147 m,2 for clams containing 380 J clam,1. For clams <5 cm deep, the threshold density decreased from 86 to 36 clams m,2 as energy content increased from 380 to 850 J clam,1. If scoters decreased dive costs by swimming with wings as well as feet (not an option for scaup), threshold prey densities were 11,12% lower. 5. Our results show that threshold densities of total prey numbers for different-sized ducks depend on prey size structure and depth in the sediments. Thus, heterogeneity in disturbance regimes and prey population dynamics can create a mosaic of patches favouring large or small predators. Whether a given area or total prey biomass will support greater numbers of larger or smaller predators will vary with these effects. [source] The uncertain blitzkrieg of Pleistocene megafaunaJOURNAL OF BIOGEOGRAPHY, Issue 4 2004Barry W. Brook Abstract We investigated, using meta-analysis of empirical data and population modelling, plausible scenarios for the cause of late Pleistocene global mammal extinctions. We also considered the rate at which these extinctions may have occurred, providing a test of the so-called ,blitzkrieg' hypothesis, which postulates a rapid, anthropogenically driven, extinction event. The empirical foundation for this work was a comprehensive data base of estimated body masses of mammals, comprising 198 extinct and 433 surviving species > 5 kg, which we compiled through an extensive literature search. We used mechanistic population modelling to simulate the role of human hunting efficiency, meat off-take, relative naivety of prey to invading humans, variation in reproductive fitness of prey and deterioration of habitat quality (due to either anthropogenic landscape burning or climate change), and explored the capacity of different modelling scenarios to recover the observed empirical relationship between body mass and extinction proneness. For the best-fitting scenarios, we calculated the rate at which the extinction event would have occurred. All of the modelling was based on sampling randomly from a plausible range of parameters (and their interactions), which affect human and animal population demographics. Our analyses of the empirical data base revealed that the relationship between body mass and extinction risk relationship increases continuously from small- to large-sized animals, with no clear ,megafaunal' threshold. A logistic ancova model incorporating body mass and geography (continent) explains 92% of the variation in the observed extinctions. Population modelling demonstrates that there were many plausible mechanistic scenarios capable of reproducing the empirical body mass,extinction risk relationship, such as specific targeting of large animals by humans, or various combinations of habitat change and opportunistic hunting. Yet, given the current imperfect knowledge base, it is equally impossible to use modelling to isolate definitively any single scenario to explain the observed extinctions. However, one universal prediction, which applied in all scenarios in which the empirical distribution was correctly predicted, was for the extinctions to be rapid following human arrival and for surviving fauna to be suppressed below their pre-,blitzkrieg' densities. In sum, human colonization in the late Pleistocene almost certainly triggered a ,blitzkrieg' of the ,megafauna', but the operational details remain elusive. [source] Autonomic Blockade Unmasks Maturational Differences in Rate-Dependent Atrioventricular Nodal Conduction and Facilitation in the MouseJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2003SAMIR SABA M.D. Maturational Differences in Murine AVN Conduction. Introduction: In large animals, rate-dependent AV nodal (AVN) properties of conduction are modulated by autonomic inputs. In this study, we investigated whether the properties of AVN conduction and facilitation are altered by autonomic blockade in the mouse and whether this effect is age dependent. Methods and Results: Young (age 4,6 weeks; n = 11) and adult (age 8,9 months; n = 11) female mice underwent in vivo electrophysiologic testing, before and after autonomic blockade. After autonomic blockade, the adult mice had significantly longer AVN effective refractory period (AVNERP; 67 ± 14 msec vs 56 ± 4 msec, P = 0.05) and functional refractory period (AVNFRP; 81 ± 10 msec vs 72 ± 4 msec, P = 0.05). With autonomic blockade, the increase from baseline of AVN Wenckebach cycle length (,AVW; 1.8 ± 8.1 msec vs 8.8 ± 3.3 msec, P = 0.04), as well as of AVNERP (,AVNERP; 3.5 ± 3.5 msec vs 21.4 ± 12.6 msec, P = 0.002) and AVNFRP (,AVNFRP; 2.3 ± 3.2 msec vs 12.8 ± 9.0 msec, P = 0.008), was significantly larger in adult than in young mice. Compared with young mice, adult mice were less likely to exhibit AVN facilitation (44% vs 90%, P = 0.03) and had smaller maximal shortening of AVN conduction times after the "test beat" for any coupling of the "facilitating beat" (4 ± 4 msec vs 7 ± 3 msec, P = 0.05). Conclusion: Complete autonomic blockade significantly increases AVN conduction times and refractory periods in adult but not in young mice. Adult mice also exhibit less AVN facilitation. Our results confirm that, like in larger animals, rate-dependent murine AVN properties of conduction are under autonomic regulation. Adult mice have higher sympathetic AVN inputs at baseline, leading to slower conduction after autonomic blockade. (J Cardiovasc Electrophysiol, Vol. 14, pp. 191-195, February 2003) [source] Molecular imaging in small animals,roles for micro-CTJOURNAL OF CELLULAR BIOCHEMISTRY, Issue S39 2002Erik L. Ritman Abstract X-ray micro-CT is currently used primarily to generate 3D images of micro-architecture (and the function that can be deduced from it) and the regional distribution of administered radiopaque indicators, within intact rodent organs or biopsies from large animals and humans. Current use of X-ray micro-CT can be extended in three ways to increase the quantitative imaging of molecular transport and accumulation within such specimens. (1) By use of heavy elements, other than the usual iodine, attached to molecules of interest or to surrogates for those molecules. The accumulation of the indicator in the physiological compartments, and the transport to and from such compartments, can be quantitated from the imaged spatial distribution of these contrast agents. (2) The high spatial resolution of conventional X-ray attenuation-based CT images can be used to improve the quantitative nature of radionuclide-based tomographic images (SPECT & PET) by providing correction for attenuation of the emitted gamma rays and the accurate delineation of physiological spaces known to selectively accumulate those indicators. Similarly, other imaging modalities which also localize functions in 2D images (such as histological sections subsequently obtained from the same specimen), can provide a synergistic combination with CT-based 3D microstructure. (3) By increasing the sensitivity and specificity of X-ray CT image contrast by use of methods such as: K-edge subtraction imaging, X-ray fluorescence imaging, imaging of the various types of scattered X-ray and the consequences of the change in the speed of X-rays through different tissues, such as refraction and phase shift. These other methods of X-ray imaging can increase contrast by more than an order of magnitude over that due to conventionally-used attenuation of X-ray. To fully exploit their potentials, much development of radiopaque indicators, scanner hardware and image reconstruction and analysis software will be needed. J. Cell. Biochem. Suppl. 39: 116,124, 2002. © 2002 Wiley-Liss, Inc. [source] Heritable body size mediates apparent life-history trade-offs in a simultaneous hermaphroditeJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2007B. L. W. MILLER Abstract Physiological trade-offs between life-history traits can constrain natural selection and maintain genetic variation in the face of selection, thereby shaping evolutionary trajectories. This study examines physiological trade-offs in simultaneously hermaphroditic banana slugs, Ariolimax dolichophallus. These slugs have high heritable variation in body size, which strongly predicts the number of clutches laid, hatching success and progeny growth rate. These fitness components were associated, but only when examined in correlation with body size. Body size mediated these apparent trade-offs in a continuum where small animals produced rapidly growing progeny, intermediate-sized animals laid many clutches and large animals had high hatching success. This study uses a novel statistical method in which the components of fitness are analysed in a mancova and related to a common covariate, body size, which has high heritability. The mancova reveals physiological trade-offs among the components of fitness that were previously masked by high variation in body size. [source] Remodeling of fracture callus in mice is consistent with mechanical loading and bone remodeling theoryJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2009Hanna Isaksson Abstract During the remodeling phase of fracture healing in mice, the callus gradually transforms into a double cortex, which thereafter merges into one cortex. In large animals, a double cortex normally does not form. We investigated whether these patterns of remodeling of the fracture callus in mice can be explained by mechanical loading. Morphologies of fractures after 21, 28, and 42 days of healing were determined from an in vivo mid-diaphyseal femoral osteotomy healing experiment in mice. Bone density distributions from microCT at 21 days were converted into adaptive finite element models. To assess the effect of loading mode on bone remodeling, a well-established remodeling algorithm was used to examine the effect of axial force or bending moment on bone structure. All simulations predicted that under axial loading, the callus remodeled to form a single cortex. When a bending moment was applied, dual concentric cortices developed in all simulations, corresponding well to the progression of remodeling observed experimentally and resulting in quantitatively comparable callus areas of woven and lamellar bone. Effects of biological differences between species or other reasons cannot be excluded, but this study demonstrates how a difference in loading mode could explain the differences between the remodeling phase in small rodents and larger mammals. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 664,672, 2009 [source] Gene transfer for hemophilia: can therapeutic efficacy in large animals be safely translated to patients?JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 8 2005K. HIGH Summary., Gene transfer is a novel area of therapeutics in which the active agent is a nucleic acid rather than a protein or small molecule. As early as 1997, investigators reported long-term expression of therapeutic levels of factor IX using gene transfer techniques in hemophilia B mice, and similar data were thereafter reported in mice with hemophilia A. Efforts to translate these results to hemophilic dog models at first yielded only marginally therapeutic levels (1%,2% normal circulating levels), but within the past few years have achieved levels in the range of 10%,20% through multiple different gene transfer strategies. Early phase clinical testing has revealed that many aspects of gene transfer in humans were accurately predicted by studies in hemophilic dogs, but that other aspects were not, and were only appreciated as a result of clinical testing. Studies in the next few years will determine whether the problems identified in preclinical and early phase clinical testing can be solved to develop a therapeutic gene transfer approach to hemophilia. [source] Pain management in horses and farm animalsJOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 4 2005Alexander Valverde DVM, DACVA Abstract Objective: This review discusses the different analgesic drugs and routes of administration used in large animals for acute pain management. General guidelines and doses are given to assist in choosing techniques that provide effective analgesia. Etiology: Noxious stimuli are perceived, recognized, and localized by specialized sensory systems located at spinal and supraspinal levels. Diagnosis: Localizing the source of the noxious stimulus as well as understanding the behavioral aspects and physiological changes that result from such insult is important to adequately diagnose and treat pain. Pain assessment is far from being definite and objective; not only are there species differences, but also individual variation. In addition, the behavioral and physiological manifestations vary with the acute or chronic nature of pain. Therapy: Pain management should include (1) selecting drugs that better control the type of pain elicited by the insult; (2) selecting techniques of analgesic drug administration that act on pathways or anatomical locations where the nociceptive information is being processed or originating from; (3) combining analgesic drugs that act on different pain pathways; and (4) provide the best possible comfort for the animal. Prognosis: Providing pain relief improves the animal's well being and outcome; however, interpreting and diagnosing pain remains difficult. Continuing research in pain management will contribute to the evaluation of the pathophysiology of pain, pain assessment, and newer analgesic drugs and techniques. [source] Role of Lung Surfactant in Respiratory Disease: Current Knowledge in Large Animal MedicineJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 2 2009U. Christmann Lung surfactant is produced by type II alveolar cells as a mixture of phospholipids, surfactant proteins, and neutral lipids. Surfactant lowers alveolar surface tension and is crucial for the prevention of alveolar collapse. In addition, surfactant contributes to smaller airway patency and improves mucociliary clearance. Surfactant-specific proteins are part of the innate immune defense mechanisms of the lung. Lung surfactant alterations have been described in a number of respiratory diseases. Surfactant deficiency (quantitative deficit of surfactant) in premature animals causes neonatal respiratory distress syndrome. Surfactant dysfunction (qualitative changes in surfactant) has been implicated in the pathophysiology of acute respiratory distress syndrome and asthma. Analysis of surfactant from amniotic fluid allows assessment of fetal lung maturity (FLM) in the human fetus and exogenous surfactant replacement therapy is part of the standard care in premature human infants. In contrast to human medicine, use and success of FLM testing or surfactant replacement therapy remain limited in veterinary medicine. Lung surfactant has been studied in large animal models of human disease. However, only a few reports exist on lung surfactant alterations in naturally occurring respiratory disease in large animals. This article gives a general review on the role of lung surfactant in respiratory disease followed by an overview of our current knowledge on surfactant in large animal veterinary medicine. [source] VERTEBRAL OSTEOLOGY AND COMPLEXITY IN LAGENORHYNCHUS ACUTUS (DELPHINIDAE) WITH COMPARISON TO OTHER DELPHINOID GENERAMARINE MAMMAL SCIENCE, Issue 3 2005Emily A. Buchholtz Abstract The vertebral column of the Atlantic white-sided dolphin, Lagenorhynchus acutus, reflects the radical reorganization of the cetacean column for locomotion in water. Both posterior thoracic and anterior caudal vertebrae have been "lumbarized," and discontinuities occur within the caudal series at the synclinal point and fluke base. Morphology changes subtly as body size increases. Neural process height increases more rapidly, and centrum length more variably, than other vertebral parameters. As a result, large animals have disproportionately tall neural processes, short necks, long mid-body regions, and short flukes. Vertebral columns of large animals also show greater complexity (range, irregularity, and polarization) of centrum length than do those of smaller animals. Comparisons among dolphins reveal that complexity trends with respect to differentiation of parts run counter to the trend with respect to number of parts, a relationship predicted by Williston in 1914. [source] Experimental research and surgery: Why, how, and when?MICROSURGERY, Issue 4 2001Antonio Di Cataldo M.D. Experimental research faces two great problems: the significant reduction of public funding and the firm opposition of the public opinion. The law forbids the use of large animals, so that it is possible to use small animals only, which require microsurgical techniques. However, even a skillful surgeon does not know how to perform microsurgery and has to begin a long and tiring training to master techniques. We think that experimental surgery should play a role because it tests the validity and safety of new surgical techniques and allows special pathophysiological aspects to be studied. Furthermore experimental surgery could represent an essential stage in the training of young surgeons. We should find a balance between observance of the law and respect of the animals and, on the other hand, the role of experimental surgery because we should not forget that its most important aim is the improvement of the health of the humankind. La ricerca sperimentale presenta delle difficoltà che dipendono in gran parte dalla scarsezza dei fondi ad essa destinati e dalla latente ostilità dell'opinione pubblica. Le leggi hanno ormai praticamente abolito la possibilità di utilizzare animali di grossa taglia per cui si possono impiegare solo piccoli animali, con la necessità di ricorrere a tecniche microchirurgiche, che non sono patrimonio di tutti i chirurghi, per cui per acquisirle bisogna sottoporsi a lunghi ed estenuanti tirocinii. Noi riteniamo che alla chirurgia sperimentale debba essere riconosciuto un suo ruolo per le possibilità che essa fornisce di saggiare la validità di nuove tecniche chirurgiche, di studiare particolari aspetti di fisiopatologia e di consentire un adeguato training dei giovani chirurghi. Sarebbe forse più giusto trovare un migliore equilibrio tra l'osservanza delle leggi ed il rispetto degli animali da un lato e la giusta collocazione della chirurgia sperimentale dall'altro, non dimenticando che quest'ultima ha come scopo unico ed esclusivo il miglioramento della salute dell'uomo. © 2001 Wiley-Liss, Inc. MICROSURGERY 21:118,120 2001 [source] Special requirements for GLP studies with ,big' animals,QUALITY ASSURANCE JOURNAL, Issue 2 2006Norbert Hochheimer Abstract The article describes the special requirements for Good Laboratory Practice (GLP) studies with farm animals. Typically, GLP studies are conducted with small laboratory animals such as mice, rats and guinea pigs; GLP studies with big animals are rarely performed. This paper highlights the differences in housing and handling for small and big animals and discusses areas specific to GLP studies with farm animals. While the article draws on observations made and regulations applicable in Germany, the information may be useful for assessing GLP studies with large animals in other countries. Copyright © 2006 John Wiley & Sons, Ltd. [source] In vitro Follicle Growth: Achievements in Mammalian SpeciesREPRODUCTION IN DOMESTIC ANIMALS, Issue 1 2001R Cortvrindt The exact mechanisms regulating in vivo folliculogenesis in mammalians have only been partly unravelled. Some processes, such as the initiation of growth of primordial follicles are still poorly understood. This increases the difficulty to culture follicles in vitro as the primordial follicles will be the ultimate starting material for culture. There are important species differences in regulation and timing of maturation, which makes it difficult to transpose techniques. Only in the mouse model, live pups were born when primordial or early preantral follicles were cultured entirely in vitro. Although no systems are as yet permitting complete in vitro culture of early follicle stages in large animals or humans, parts of folliculogenesis have been successfully reproduced in vitro. This review summarizes achievements of the last years in follicle culturing starting off at several stages of development. Future applications of in vitro follicle culture include fertility preservation for humans, preservation of rare animal species and creation of oocyte banks for research. [source] Viral vectors as tools to model and treat neurodegenerative disordersTHE JOURNAL OF GENE MEDICINE, Issue 5 2005N. Déglon Abstract The identification of disease-causing genes in familial forms of neurodegenerative disorders and the development of genetic models closely replicating human central nervous system (CNS) pathologies have drastically changed our understanding of the molecular events leading to neuronal cell death. If these achievements open new opportunities of therapeutic interventions, including gene-based therapies, the presence of the blood-brain barrier and the post-mitotic and poor regenerative nature of the target cells constitute important challenges. Efficient delivery systems taking into account the specificity of the CNS are required to administer potential therapeutic candidates. In addition, genetic models in large animals that replicate the late stages of the diseases are in most cases not available for pre-clinical studies. The present review summarizes the potential of viral vectors as tools to create new genetic models of CNS disorders in various species including primates and the recent progress toward viral gene therapy clinical trials for the administration of therapeutic candidates into the brain. Copyright © 2005 John Wiley & Sons, Ltd. [source] Regulation of lactate production at the onset of ischaemia is independent of mitochondrial NADH/NAD+: insights from in silico studiesTHE JOURNAL OF PHYSIOLOGY, Issue 3 2005Lufang Zhou Ischaemia decreases mitochondrial NADH oxidation, activates glycolysis, increases the NADH/NAD+ ratio, and causes lactate production. The mechanisms that regulate anaerobic glycolysis and the NADH/NAD+ ratio during ischaemia are unclear. Although continuous measurements of metabolic fluxes and NADH/NAD+ in cytosol and mitochondria are not possible in vivo with current experimental techniques, computational models can be used to predict these variables by simulations with in silico experiments. Such predictions were obtained using a mathematical model of cellular metabolism in perfused myocardium. This model, which distinguishes cytosolic and mitochondrial domains, incorporates key metabolic species and processes associated with energy transfer. Simulation of metabolic responses to mild, moderate and severe ischaemia in large animals showed that mitochondrial NADH/NAD+ was rapidly reset to higher values in proportion to the reduced O2 delivery and myocardial oxygen consumption . Cytosolic NADH/NAD+, however, showed a biphasic response, with a sharp initial increase that was due to activation of glycogen breakdown and glycolysis, and corresponded with lactate production. Whereas the rate of glycolysis and the malate,aspartate shuttle had a significant effect on the cytosolic NADH/NAD+, their effects on the mitochondrial NADH/NAD+ were minimal. In summary, model simulations of the metabolic response to ischaemia showed that mitochondrial NADH/NAD+ is primarily determined by O2 consumption, while cytosolic NADH/NAD+ is largely a function of glycolytic flux during the initial phase, and is determined by mitochondrial NADH/NAD+ and the malate,aspartate shuttle during the steady state. [source] Translational Research: Animal Models of Obliterative Bronchiolitis after Lung TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 9 2009M. Sato Obliterative bronchiolitis (OB) or chronic graft dysfunction remains the major limitation to long-term success of lung transplantation. Investigation using animal models is a critical component of research to understand the underlying pathological mechanisms and to develop novel preventive and therapeutic strategies for OB. Multiple animal models of OB exist, including orthotopic lung transplantation in rodents and large animals, orthotopic tracheal transplantation and heterotopic transplantation of a trachea in variable sites such as subcutaneous, intraomental and intrapulmonary sites. The most important issue for researchers is not specifically which model is the best but which is the most appropriate model to test their scientific hypothesis. For example, while orthotopic lung transplantation best mimics the overall surgical procedure, a question regarding fibrotic processes of OB may be better answered using heterotopic tracheal transplant models because of their reliable reproducibility of allograft obliterative airway fibrosis. Animal models should be continuously refined, modified and sometimes combined to fit the particular research purpose. We review the available animal models, their modifications and possible applications to assist researchers in choosing the appropriate model for their intended research. [source] Rotating Frame for the In-situ Fixation of Large AnimalsANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2009F.-V. Salomon Summary The frame for the in-situ fixation of large animals can be rotated around its longtitudinal axis. Thereby the fixing procedure is improved and the anatomical preparation is easier. [source] Forest Elephants: Tree Planters of the CongoBIOTROPICA, Issue 4 2009Stephen Blake ABSTRACT The abundance of large vertebrates is rapidly declining, particularly in the tropics where over-hunting has left many forests structurally intact but devoid of large animals. An urgent question then, is whether these ,empty' forests can sustain their biodiversity without large vertebrates. Here we examine the role of forest elephant (Loxodonta africana cyclotis) seed dispersal in maintaining the community structure of trees in the Ndoki Forest, northern Congo. Analysis of 855 elephant dung piles suggested that forest elephants disperse more intact seeds than any other species or genus of large vertebrate in African forests, while GPS telemetry data showed that forest elephants regularly disperse seeds over unprecedented distances compared to other dispersers. Our analysis of the spatial distribution of trees from a sample of 5667 individuals showed that dispersal mechanism was tightly correlated with the scale of spatial aggregation. Increasing amounts of elephant seed dispersal was associated with decreasing aggregation. At distances of<200 m, trees whose seeds are dispersed only by elephants were less aggregated than the random expectation, suggesting Janzen,Connell effects on seed/seedling mortality. At the landscape scale, seed dispersal mode predicted the rate at which local tree community similarity decayed in space. Our results suggest that the loss of forest elephants (and other large-bodied dispersers) may lead to a wave of recruitment failure among animal-dispersed tree species, and favor regeneration of the species-poor abiotically dispersed guild of trees. [source] | ||||||||||||||||