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Ventral Aspect (ventral + aspect)
Selected AbstractsDevelopment and topography of the lateral olfactory tract in the mouse: Imaging by genetically encoded and injected fluorescent markersDEVELOPMENTAL NEUROBIOLOGY, Issue 8 2006Andreas Walz Abstract In mammals, conventional odorants are detected by OSNs located in the main olfactory epithelium of the nose. These neurons project their axons to glomeruli, which are specialized structures of neuropil in the olfactory bulb. Within glomeruli, axons synapse onto dendrites of projection neurons, the mitral and tufted (M/T) cells. Genetic approaches to visualize axons of OSNs expressing a given odorant receptor have proven very useful in elucidating the organization of these projections to the olfactory bulb. Much less is known about the development and connectivity of the lateral olfactory tract (LOT), which is formed by axons of M/T cells connecting the olfactory bulb to central neural regions. Here, we have extended our genetic approach to mark M/T cells of the main olfactory bulb and their axons in the mouse, by targeted insertion of IRES-tauGFP in the neurotensin locus. In NT-GFP mice, we find that M/T cells of the main olfactory bulb mature and project axons as early as embryonic day 11.5. Final innervation of central areas is accomplished before the end of the second postnatal week. M/T cell axons that originate from small defined areas within the main olfactory bulb, as visualized by localized injections of fluorescent tracers in wild-type mice at postnatal days 1 to 3, follow a dual trajectory: a branch of tightly packed axons along the dorsal aspect of the LOT, and a more diffuse branch along the ventral aspect. The dorsal, but not the ventral, subdivision of the LOT exhibits a topographical segregation of axons coming from the dorsal versus ventral main olfactory bulb. The NT-GFP mouse strain should prove useful in further studies of development and topography of the LOT, from E11.5 until 2 weeks after birth. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source] Development of equine upper airway fluid mechanics model for Thoroughbred racehorsesEQUINE VETERINARY JOURNAL, Issue 3 2008V. RAKESH Summary Reason for performing study: Computational fluid dynamics (CFD) models provide the means to evaluate airflow in the upper airways without requiring in vivo experiments. Hypothesis: The physiological conditions of a Thoroughbred racehorse's upper airway during exercise could be simulated. Methods: Computed tomography scanned images of a 3-year-old intact male Thoroughbred racehorse cadaver were used to simulate in vivo geometry. Airway pressure traces from a live Thoroughbred horse, during exercise was used to set the boundary condition. Fluid-flow equations were solved for turbulent flow in the airway during inspiratory and expiratory phases. The wall pressure turbulent kinetic energy and velocity distributions were studied at different cross-sections along the airway. This provided insight into the general flow pattern and helped identify regions susceptible to dynamic collapse. Results: The airflow velocity and static tracheal pressure were comparable to data of horses exercising on a high-speed treadmill reported in recent literature. The cross-sectional area of the fully dilated rima glottidis was 7% greater than the trachea. During inspiration, the area of highest turbulence (i.e. kinetic energy) was in the larynx, the rostral aspect of the nasopharynx was subjected to the most negative wall pressure and the highest airflow velocity is more caudal on the ventral aspect of the nasopharynx (i.e. the soft palate). During exhalation, the area of highest turbulence was in the rostral and mid-nasopharynx, the maximum positive pressure was observed at the caudal aspect of the soft palate and the highest airflow velocity at the front of the nasopharynx. Conclusions and clinical relevance: In the equine upper airway collapsible area, the floor of the rostral aspect of the nasopharynx is subjected to the most significant collapsing pressure with high average turbulent kinetic during inhalation, which may lead to palatal instability and explain the high prevalence of dorsal displacement of the soft palate (DDSP) in racehorses. Maximal abduction of the arytenoid cartilage may not be needed for optimal performance, since the trachea cross-sectional area is 7% smaller than the rima glottidis. [source] Requirement of Runx1/AML1/PEBP2,B for the generation of haematopoietic cells from endothelial cellsGENES TO CELLS, Issue 1 2001Tomomasa Yokomizo Recent studies revealing that endothelial cells derived from E8.5-E10.5 mouse embryos give rise to haematopoietic cells appear to correspond to previous histological observations that haematopoietic cell clusters are attached to the ventral aspect of dorsal aorta in such a way as if they were budding from the endothelial cell layer. Gene disruption studies have revealed that Runx1/AML1 is required for definitive haematopoiesis but not for primitive haematopoiesis, but the precise stage of gene function is not yet known. We found that mice deficient in Runx1/AML1 (an , subunit of the transcription factor PEBP2/CBF) lack c-Kit+ haematopoietic cell clusters in the dorsal aorta, omphalomesenteric and umbilical arteries, as well as yolk sac vessels. Moreover, endothelial cells sorted from the embryo proper and the yolk sac of AML1,/, embryos are unable to differentiate into haematopoietic cells on OP9 stromal cells, whereas colonies of AML1,/, endothelial cells can be formed in culture. These results strongly suggest that the emergence of haematopoietic cells from endothelial cells represents a major pathway of definitive haematopoiesis and is an event that also occurs in the yolk sac in vivo, as suggested by earlier in vitro experiments. [source] Exercise prevents age-related decline in nitric-oxide-mediated vasodilator function in cutaneous microvesselsTHE JOURNAL OF PHYSIOLOGY, Issue 14 2008Mark A. Black Ageing is associated with impaired endothelium-derived nitric oxide (NO) function in human microvessels. We investigated the impact of cardiorespiratory fitness and exercise training on physiological and pharmacological NO-mediated microvascular responses in older subjects. NO-mediated vasodilatation was examined in young, older sedentary and older fit subjects who had two microdialysis fibres embedded into the skin on the ventral aspect of the forearm and laser Doppler probes placed over these sites. Both sites were then heated to 42°C, with Ringer solution infused in one probe and N -nitro- l -arginine methyl ester (l -NAME) through the second. In another study, three doses of ACh were infused in the presence or absence of l -NAME in similar subjects. The older sedentary subjects then undertook exercise training, with repeat studies at 12 and 24 weeks. The NO component of the heat-induced rise in cutaneous vascular conductance (CVC) was diminished in the older sedentary subjects after 30 min of prolonged heating at 42°C (26.9 ± 3.9%CVCmax), compared to older fit (46.2 ± 7.0%CVCmax, P < 0.05) and young subjects (41.2 ± 5.2%CVCmax, P < 0.05), whereas exercise training in the older sedentary group enhanced NO-vasodilator function in response to incremental heating (P < 0.05). Similarly, the NO contribution to ACh responses was impaired in the older sedentary versus older fit subjects (low dose 3.2 ± 1.3 versus 6.6 ± 1.3%CVCmax; mid dose 11.4 ± 2.4 versus 21.6 ± 4.5%CVCmax; high dose 35.2 ± 6.0 versus 52.6 ± 7.9%CVCmax, P < 0.05) and training reversed this (12 weeks: 13.7 ± 3.6, 28.9 ± 5.3, 56.1 ± 3.9%CVCmax, P < 0.05). These findings indicate that maintaining a high level of fitness, or undertaking exercise training, prevents age-related decline in indices of physiological and pharmacological microvascular NO-mediated vasodilator function. Since higher levels of NO confer anti-atherogenic benefit, this study has potential implications for the prevention of microvascular dysfunction in humans. [source] ORIGINAL RESEARCH,SURGERY: Penile Prosthesis Implantation in Cases of Fibrosis: Ultrasound-Guided Cavernotomy and Sheathed Trochar ExcavationTHE JOURNAL OF SEXUAL MEDICINE, Issue 3 2007Osama Shaeer MD ABSTRACT Introduction., Implantation of a penile prosthesis into fibrosed corpora cavernosa is a difficult and risky procedure. Specialized instruments that assist safer and more efficient excavation include Otis Urethrotome and various cavernotomes, all of which operate underneath the tunica albuginea, out of sight. The blind use of such instruments can result in perforation of the tunica albuginea or injury to the urethra. Aim., This work describes the utility of ultrasonography for adding visual monitoring to any of the above-mentioned instruments, maintaining them in the mid-corpus cavernosum position to avoid perforation, and describes the application of alternative sheathed, sharp instruments that allow fast, efficient, and visually monitored drilling into fibrous tissue. Main Outcome Measures., Clinical outcome data were examined. Methods., Surgery was performed on five cases with extensive fibrosis of the penis. Initial blunt dilatation by Hegar dilators faced considerable resistance. An ultrasound probe was applied to the ventral aspect of the penis. A laparoscopy sheath was advanced under ultrasound guidance up to the fibrous tissue. A sharp laparoscopy trochar was inserted through the sheath. Its tip was oriented in the mid-corpus cavernosum by longitudinal and transverse sonography sections, as it drilled into the fibrous tissue. Laparoscopy scissors were used in the same fashion to cut fibrous tissue lumps. After full excavation, penile prosthesis was implanted. Results., All implants survived adequately. No complications occurred following implantation. Operative time ranged from 50 to 60 minutes. No difficulty was encountered at excavation. Conclusion., Ultrasound guidance can be a handy adjunct to any of the available techniques developed for excavating the fibrosed corpora cavernosa, with a possible decrease in difficulty and complication rate of the procedure. Utility of sheathed, sharp instruments guided by sonography is an alternative to the cavernotomes, allowing fast and efficient drilling into fibrous tissue. Shaeer O. Penile prosthesis implantation in cases of fibrosis: Ultrasound-guided cavernotomy and sheathed trochar excavation. J Sex Med 2007;4:809,814. [source] Aortic arch variation analyzed by using plastinationCLINICAL ANATOMY, Issue 6 2002Mircea-Constantin Sora Abstract Different ramification patterns can be observed during the development of the aortic arch. In this study a common trunk (CT), which subsequently branched into the brachiocephalic trunk (BT) and left common carotid artery (LCCA), arose from the aortic arch. The LCCA arose from the CT 10.27 mm above the aortic arch. After crossing the ventral aspect of the trachea and esophagus, the LCCA became situated on the left side of the esophagus. The caliber and length of the main branches of the aortic arch were determined and compared to reports in the literature. This variation was discovered in the context of producing transverse body slices using an E12 plastination process. Clin. Anat. 15:379,382, 2002. © 2002 Wiley-Liss, Inc. [source] Modulation of histamine H3 receptors in the brain of 6-hydroxydopamine-lesioned ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2000Oleg V. Anichtchik Abstract Parkinson's disease is a major neurological disorder that primarily affects the nigral dopaminergic cells. Nigral histamine innervation is altered in human postmortem Parkinson's disease brains. However, it is not known if the altered innervation is a consequence of dopamine deficiency. The aim of the present study was to investigate possible changes in the H3 receptor system in a well-characterized model of Parkinson's disease , the 6-hydroxydopamine (6-OHDA) lesioned rats. Histamine immunohistochemistry showed a minor increase of the fibre density index but we did not find any robust increase of histaminergic innervation in the ipsilateral substantia nigra on the lesioned side. In situ hybridization showed equal histidine decarboxylase mRNA expression on both sides in the posterior hypothalamus. H3 receptors were labelled with N-alpha-[3H]-methyl histamine dihydrochloride ([3H] NAMH). Upregulation of binding to H3 receptors was found in the substantia nigra and ventral aspects of striatum on the ipsilateral side. An increase of GTP-,-[35S] binding after H3 agonist activation was found in the striatum and substantia nigra on the lesioned side. In situ hybridization of H3 receptor mRNA demonstrated region-specific mRNA expression and an increase of H3 receptor mRNA in ipsilateral striatum. Thus, the histaminergic system is involved in the pathological process after 6-OHDA lesion of the rat brain at least through H3 receptor. On the later stages of the neurotoxic damage, less H3 receptors became functionally active. Increased H3 receptor mRNA expression and binding may, for example, modulate GABAergic neuronal activity in dopamine-depleted striatum. [source] Development of the human hypogastric nerve sheath with special reference to the topohistology between the nerve sheath and other prevertebral fascial structuresCLINICAL ANATOMY, Issue 6 2008Yusuke Kinugasa Abstract Semi-serial sections from the lumbosacral region of nine fetuses (8,25 weeks gestation) were examined to clarify the lumbar prevertebral fascial arrangement. The prevertebral fasciae became evident after 12 weeks of age. After 20 weeks of age, the hypogastric nerve (HGN) was sandwiched by two fascial structures; the ventral fascia which seemed to correspond to the mesorectal fascia, whereas the dorsal fascia corresponded to the presacral fascia. These fasciae or the HGN sheaths extended laterally along the ventral aspects of the great vessels and associated lymph follicles. The ventral fascia is, to some extent, fused with the mesocolon descendens on the left side of the body. Notably, the lateral continuation of these two fasciae also sandwiches the left ureter, but not the right ureter, presumably due to modifications by the left-sided fusion fascia. A hypothetical common sheath for the HGN and ureter (i.e., the ureterohypogastric or vesicohypogastric fascia) might thus be an oversimplification. Before retroperitoneal fixation, the morphology of the peritoneal recess along the mesocolon descendens and mesosigmoid suggested interindividual differences in location, shape, and size. Therefore, in adults the ease of surgical separation of the rectum and left-sided colon from the HGN seems to depend on interindividual differences in the development of the embryonic peritoneal recess. On the caudal side of the second sacral segment, fascial structures were restricted along and around the HGN, pelvic splanchnic nerve, and pelvic plexus. The rectal lateral ligament thus seems to represent a kind of migration fascia formed by mechanical stress. Clin. Anat. 21:558,567, 2008. © 2008 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||