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Hemodynamic effects of anesthetics in a mouse model assessed by Laser Doppler Perfusion and echocardiographic imaging
No full textAnesthetics can alter microvascular perfusion, affecting tissue oxygenation and delivery of vital substrates. The ??2???adrenergic agonist dexmedetomidine and the ?????blocker acepromazine are powerful sedatives with remarkable hemodynamic effects. Some authors reported an attenuation of the ??2???adrenergic agonist pressor response by an acepromazine???xylazine combination in dogs. We investigated non???invasively the microcirculatory effects of dexmedetomidine, of acepromazine and of their combination in isoflurane anesthetized mice by Laser Doppler Perfusion Imaging (LDPI). Thirty???two age???matched and sex???paired CD1 mice underwent 1.5% isoflurane anesthesia, followed by intraperitoneal injection of either 5 mg/kg acepromazine, or 1 mg/kg dexmedetomidine, or by their combination. Body temperature was adjusted to 36 °C. Heart (HR) and breath (BR) rate were recorded. Hind paws blood flow (Perfusion Units, volt) was recorded by LDPI 10 and 20 minutes after isoflurane induction, at different intervals after treatments, and after reversing dexmedetomidine by the ??2??? antagonist atipamezole. BR decreased in all groups without significant differences to baseline (P>0.05). Dexmedetomidine sharply reduced over time HR (P0.05). Acepromazine+dexmedetomidine decreased HR (P0.05); atipamezole gradually raised HR close to baseline (P>0.05). Peripheral perfusion under isoflurane anesthesia showed an increasing trend after 10 and 20 minutes, without differences among groups (P=0.1). Acepromazine increased perfusion between 10 and 20 minutes (P=0.005). Dexmedetomidine reduced blood perfusion after 5 minutes (P=0.0001), followed by an increase after 15 minutes (P=0.008). No significant changes were seen 5 minutes after atipamezole (P=0.9). Acepromazine+dexmedetomidine resulted in steady perfusion values over time (P=0.44), which after atipamezole increased very close to baseline (P=0.237). Acepromazine+dexmedetomidine in mice produced more temperate, steady peripheral perfusion values compared to those following single agent, reducing the entity of the ??2 ???agonist biphasic hemodynamic pattern. Our translational approach by LDPI in a mouse model allows an easy, accurate and non invasive measurement of the effects of anesthetics on peripheral microcirculation. 1. Alvaides RK, Neto FJ, Aguiar AJ, et al. Sedative and cardiorespiratory effects of acepromazine or atropine given before Dexmedetomidine in dogs. Vet Rec 2008; 26: 852???856. 2. B. J. A. Janssen, T. De Celle, J. J. M. Debets, A. E. et al, ???Effects of anesthetics on systemic hemodynamics in mice,??? Am J Physiol Heart Circ Physiol, vol. 4, no. 287, pp. 1618???1624, 2004. 3. Adelaide Greco, Monica Ragucci, Raffaele Liuzzi, Sara Gargiulo, Matteo Gramanzini, e al. Reproducibility and Standardization of Laser doppler Imaging technique for the evaluation of normal mice hindlimb
Evaluation of Growth Patterns and Body Composition in C57Bl/6J Mice Using Dual Energy X-Ray Absorptiometry
Get PDFThe normal growth pattern of female C57BL/6J mice, from 5 to 30 weeks of age, has been investigated in a longitudinal study. Weight, body surface area (BS), and body mass index (BMI) were evaluated in forty mice. Lean mass and fat mass, bone mineral content (BMC), and bone mineral density (BMD) were monitored by dual energy X-ray absorptiometry (DEXA). Weight and BS increased linearly (16.15 ± 0.64-27.64 ± 1.42 g; 51.13 ± 0.74-79.57 ± 2.15 cm(2), P < 0.01), more markedly from 5 to 9 weeks of age (P < 0.001). BMD showed a peak at 17 weeks (0.0548 ± 0.0011 g/cm(2) ∗ m, P < 0.01). Lean mass showed an evident gain at 9 (15.8 ± 0.8 g, P < 0.001) and 25 weeks (20.5 ± 0.3 g, P < 0.01), like fat mass from 13 to 17 weeks (2.0 ± 0.4-3.6 ± 0.7 g, P < 0.01). BMI and lean mass index (LMI) reached the highest value at 21 weeks (3.57 ± 0.02-0.284 ± 0.010 g/cm(2), resp.), like fat mass index (FMI) at 17 weeks (0.057 ± 0.009 g/cm(2)) (P < 0.01). BMI, weight, and BS showed a moderate positive correlation (0.45-0.85) with lean mass from 5 to 21 weeks. Mixed linear models provided a good prediction for lean mass, fat mass, and BMD. This study may represent a baseline reference for a future comparison of wild-type C57BL/6J mice with models of altered growth
Mice Anesthesia, Analgesia, and Care, Part II: Special Considerations for Preclinical ImagingStudies
No full textAnimal experiments are necessary for a better understanding of diseases and for developing new therapeutic strategies. The mouse (Mus musculus) is currently the most popular laboratory animal in biomedical research. Mice imaging procedures are increasingly
used in preclinical research because they allow in vivo monitoring and they are readily available for longitudinal and noninvasive
studies as well as investigations into the evolution of diseases and the effects of new therapies. New imaging techniques and
sophisticated laboratory animal imaging tools are currently producing a large body of evidence about the possible interference of
anesthesia with different imaging methods that have the potential to compromise the results of in vivo studies. The purpose of this
article is to review the existing literature on molecular imaging studies in mice, to describe the effects of different anesthetic protocols on their outcome, and to report our own experience with such studies
Mice Anesthesia, Analgesia, and Care, Part I: Anesthetic Considerations in Preclinical Research
No full textAnimal experiments are necessary for a better understanding of diseases and for developing new therapeutic strategies. The mouse
(Mus musculus) is currently the most popular laboratory animal in biomedical research. Experimental procedures on animals often
require anesthesia and/or analgesia to obtain adequate immobilization and to reduce stress or pain. Mice anesthesia is challenging
for several reasons including the animals’ size, metabolic rate, and the high risk of hypothermia and hypoglycemia. Moreover,
anesthetic agents influence physiological parameters, further interfering with experimental results. Small animal imaging procedures
are increasingly used in biomedical research both because the animals allow in vivo monitoring and because they are readily
available for longitudinal and noninvasive studies as well as investigations into the evolution of diseases and the effects of new
therapies. Anesthesia must adapt to the imaging technique, the procedure length, and the aim of the study. The purpose of this
article is to review the existing literature on anesthetic protocols adopted in mice for molecular imaging studies and to report our
experience
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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