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Different Animal Species (different + animal_species)
Selected AbstractsEvidences of the gender-related differences in cardiac repolarization and the underlying mechanisms in different animal species and humanFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 1 2006Jianhua Cheng Abstract Clinical and experimental studies have shown that gender differences exist in cardiac repolarization in various animal species and human, as is evidenced by significantly longer QT, JT intervals and action potential duration in females than in males due to a reduced repolarization reserve in females. The latter is shown by the relatively greater increase in ventricular repolarization and higher incidence of torsades de pointes (TdP) in preparations from females by drugs blocking repolarizing K+ currents. These results can be modulated by gonadectomy, suggesting that gonadal steroids are important determinants of gender difference in repolarization. In human subjects, QT and JT intervals are longer in women, whereas QT dispersion and Tp-e interval (the interval from the peak to the end of T wave) are longer in men. At slow heart rates greater prolongation in QT and increase in transmural repolarization heterogeneity (i.e. increase in Tp-e) may predispose to TdP tachycardias in women. In healthy postmenopausal women, hormone replacement therapy with estrogen alone usually produced a prolongation of QT interval, while estrogen plus progesterone had no significant effects on QT interval but reduced QT dispersion. Along with these, there are still conflicting data reported. Further work is needed before the elucidation of the basis of gender differences in ventricular repolarization. [source] Pharmacological interventions in aging and age-associated disordersGERIATRICS & GERONTOLOGY INTERNATIONAL, Issue 2 2007Kenichi Kitani In the present study, past attempts using different pharmaceuticals and chemicals which were reported to prolong lifespans of animals are critically reviewed. Despite a large number of trials in animals and humans, the validity of supplementation of antioxidant vitamins such as vitamins A, E and C for improving human health remains unresolved at present. A recent approach using antioxidant mimetics called the EUK series which, despite an initial enthusiastically reported success in prolonging the lifespan of nematodes, remains again unsettled because of the failure in reproducing the initial success by follow-up studies. ,-Phenyl- tert -butylnitrone and related nitrones were initially introduced as radical scavengers. Some of these (e.g. disodium 2,4-disulfophenyl-N- tert -butylnitrone) are at phase 3 clinical trials as an agent to treat cerebral stroke. This effect, however, appears at least in part to be related to signal transduction which makes these agents effective against cerebral stroke even when they are administered later than its onset. (,)Deprenyl is a monoamine oxidase-B inhibitor and has some neuroprotective and anti-apoptotic effects. The drug has also been shown to prolong the lifespans of at least four different animal species. The drug upregulates superoxide dismutase and catalase activities in selective brain regions of dopaminergic nature. These effects on antioxidant enzyme activities are suspected to be causally related to its effect on lifespans of animals. Future trials using these and other drugs are expected to open new doors for interventions in aging and age-associated disorders in humans. [source] Tachykinins and their possible modulatory role on testicular function: a reviewINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 4 2003Luciano Debeljuk Summary Tachykinins are vasoactive and smooth muscle-contracting peptides with widespread localizations. Tachykinins have been localized in the nerve fibres that supply the testes, in the Leydig cells of different animal species, and also in Sertoli cells of the Siberian hamster testes. The presence of substance P (SP) has also been demonstrated in ejaculated human spermatozoa and in the seminal plasma. Tachykinins have been shown to inhibit the release of testosterone by testicular fragments or by isolated Leydig cells in vitro. Acting on Sertoli cells, tachykinins have been shown to stimulate the release of lactate and transferrin by these cells in vitro, and also to stimulate aromatase activity. Leydig and Sertoli cells express the Preprotachykinin A gene, and this fact strongly suggests that tachykinins can be synthesized in the testes. These findings suggest that tachykinins may have a physiological function in the testes as modulators of the functions of the different cell types contained in these organs. [source] Investigation of the genetic diversity among isolates of Salmonella enterica serovar Dublin from animals and humans from England, Wales and IrelandJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2002E. Liebana Aims: To assess the degree of genetic diversity among animal Salmonella Dublin UK isolates, and to compare it with the genetic diversity found among human isolates from the same time period. Methods and Results: One hundred isolates (50 human and 50 animal) were typed using plasmid profiling, XbaI-pulsed field gel electrophoresis (PFGE) and PstI- SphI ribotyping. Antimicrobial resistance data to 16 antibiotics was presented, and the presence of class-I integrons was investigated by real-time PCR. Seven different plasmid profiles, 19 ribotypes and 21 PFGE types were detected. A combination of the three methods allowed clear differentiation of 43 clones or strains. Eighteen isolates were resistant to at least one antimicrobial; five of them were multi-resistant and of these, only three presented class I integrons. Conclusions: Ribotyping data suggest the existence of at least three very different clonal lines; the same distribution in well-defined groups was not evident from the PFGE data. The existence of a variety of clones in both animals and humans has been demonstrated. A few prevalent clones seem to be widely disseminated among different animal species and show a diverse geographical and temporal distribution. The same clones were found in animals and humans, which may infer that both farm and pet animals may act as potential vehicles of infection for humans. Some other clones seem to be less widely distributed. Clustering analysis of genomic fingerprints of Salmonella Dublin and Salm. Enteritidis isolates confirms the existence of a close phylogenetic relationship between both serotypes. Significance and Impact of the Study: This paper describes the utility of a multiple genetic typing approach for Salm. Dublin. It gives useful information on clonal diversity among human and animal isolates. [source] Antimicrobial resistance in livestockJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 2 2003B. Catry Antimicrobial resistance may become a major problem in veterinary medicine as a consequence of the intensive use and misuse of antimicrobial drugs. Related problems are now arising in human medicine, such as the appearance of multi-resistant food-borne pathogens. Product characteristics, dose, treatment interval and duration of treatment influence the selection pressure for antimicrobial drug resistance. There are theoretical, experimental and clinical indications that the emergence of de novo resistance in a pathogenic population can be prevented by minimizing the time that suboptimal drug levels are present in the infected tissue compartment. Until recently, attention has been focused on target pathogens. However, it should be kept in mind that when antimicrobial drugs are used in an individual, resistance selection mainly affects the normal body flora. In the long term, this is at least equally important as resistance selection in the target pathogens, as the horizontal transfer of resistance genes converts almost all pathogenic bacteria into potential recipients for antimicrobial resistance. Other factors contributing to the epidemiology of antimicrobial resistance are the localization and size of the microbial population, and the age, immunity and contact intensity of the host. In livestock, dynamic herd-related resistance patterns have been observed in different animal species. [source] Comparative Histology and Vibration of the Vocal Folds: Implications for Experimental Studies in Microlaryngeal Surgery ,THE LARYNGOSCOPE, Issue 5 2000C. Gaelyn Garrett MD Abstract Objectives/Hypothesis To determine the most suitable animal model for experimental studies on vocal fold surgery and function by a histological comparison of the microflap surgical plane and laryngeal videostroboscopy (LVS) in different species of animals. A second goal was to determine how the layered vocal fold structure in humans and three different animal species affects surgical dissection within the lamina propria. Study Design Prospective laboratory. Methods Three larynges each from dogs, monkeys, and pigs were compared with three ex vivo human larynges. Microflap surgery was performed on one vocal fold from each larynx. Both the operated and nonoperated vocal folds were examined histologically using stains specific for elastin, mature collagen, and ground substance. Based on the histological results, LVS was performed on two dogs and two pigs after first performing a tracheotomy for ventilation and airflow through the glottis. Arytenoid adduction sutures were placed to facilitate vocal fold adduction. Results The distributions of the collagen and elastin fibers were found to differ among the species with concentrations varying within species. Unlike the human vocal fold, which has a higher elastin concentration in the deeper layers of the lamina propria, both the pig and the dog had a thin band of elastin concentrated just deep to the basement membrane zone in the superficial layer. Just deep to this thin band, the collagen and the elastin were less concentrated. The monkey vocal fold had a very thin mucosal layer with less elastin throughout the mucosa. The microflap dissections in each of the dog, pig, and human vocal folds were similar, being located within that portion of the superficial lamina propria where the elastin and mature collagen are less concentrated. The microflap plane in the monkey vocal fold was more deeply located near the vocalis fibers. Despite the differences in elastin concentration, the microflap plane in both the dog and the pig was found to be similar to that in humans. The dog anatomy was much more suitable for microsuspension laryngoscopy and stroboscopic examination. The dog vocal folds vibrated in a similar fashion to human vocal folds with mucosal waves and vertical phase differences, features not seen in the pig vocal folds. Conclusions Based on both the histological and stroboscopic results, the dog was believed to be a more suitable animal model for studies on vocal fold surgery, acknowledging that no animal's laryngeal anatomy is identical to that of the human. The dog LVS model presented allows for longitudinal laryngeal studies requiring repeated examinations at multiple time periods with histological correlation applied at sacrifice. [source] | ||||||||||