O gânglio celíaco pertence ao plexo celíaco que consiste numa rede de nervos e tecidos de suporte. Os gânglios celíacos, pares, são alongados e situam-se ao longo da face caudal da origem da artéria celíaca. No lado esquerdo o gânglio está ligado por um ramo interganglionar. Ele está intimamente em contato com a superfície da aorta. A inervação autônoma da maioria dos órgãos abdominais faz-se pelo plexo celíaco e estes incluem o pâncreas, fígado, rim, vesícula biliar, epíplon, mesentério, estômago, intestino delgado e porções ascendente e transversa do cólon. A desnutrição protéico-calórica é um dos maiores problemas de saúde pública no mundo, representando nas nações subdesenvolvidas cerca de 40% das causas dos pacientes hospitalizados. Desta forma o estudo da inervação extrínseca do trato gastrintestinal (representada pelo gânglio celíaco) de ratos, sob os aspectos estereológicos e morfométricos, durante estados de desnutrição protéica será fundamental para aferir objetivamente (e não empiricamente) os possíveis danos neuronais ocasionados pela mesma. Ainda, o conhecimento destas informações quantitativas pode ser útil no entendimento da patogênese da neuropatia autonômica hipoproteica e conseqüentemente no seu tratamento, melhorando a qualidade de vida de pacientes animais e humanos. No decorrer deste estudo foram utilizados seis gânglios celíacos esquerdos provenientes de ratos Albinus Wistar neonatos machos provenientes de acasalamento durante um período de sete a dez dias. Três dos ratos eram desnutridos e três clinicamente saudáveis (ausência clínica de neuropatias) que foram usados como controle. Para os animais foram oferecida água sem restrições e uma dieta protéica (20% de proteína-caseina) para as fêmeas que gerarem o grupo controle constituído por três animais que serão denominados nutridos (N) e uma dieta hipoproteica (5% de caseína) para as fêmeas que gerarem o grupo desnutrido também composto por de três animais (D). A amostragem foi realizada de modo uniforme, sistemático e aleatório, volume ganglionar ou volume do gânglio (vg), número total de neurônios (n), densidade neuronal (nv), volume neuronal (vn), densidade de volume neuronal (vv). Todos os parâmetros estereológicos apresentaram valores superiores (bastante significativos). Os resultados sugerem a existência de diferenças biológicas, ou seja, os animais desnutridos apresentavam neurônios maiores e em maior número, mas distribuídos e mais afastados uns dos outros, já os desnutridos possuíam neurônios menores, menos numerosos e distribuídos em um número menor no gânglio. / The celiac ganglion belongs to the celiac plexus which consists of a net of nerves and supportive tissues. The celiac ganglia, even, are alonged and locate along the caudal face of the origin of the celiac artery. On the left side the ganglion is linked by an interganglionar branch. It is intimately in contact with the surface of the aorta. The autonomous innervation of most of the abdominal organs is made by the celiac plexus and these include the pancreas, liver, kidney, gall bladder, epíplon, mesentery, stomach, small intestine and ascendant and transversal portions of the colon. The proteic-caloric undernourishment is one of the largest problems of public health in the world, representing about 40% of the hospitalized patients in underdeveloped nations. Thus, the study of the extrinsic innervation of the gastrointestinal treatment (represented by the celiac ganglion) of rat, under the stereological and morphometric aspects, during states of proteic denutrition will be fundamental to objectively precise (and not empirically) the possible neuronal damages caused by the undernourishment. Still, the knowledge of these quantitative information can be useful in the understanding of the pathogenesis of the autonomous hipoproteic neuropathy and consequently in its treatment, improving the quality of life of patients, animals and humans. During this study, six left celiac ganglions of newborn male rats Albinus Wistar coming from coupling during a period from seven to ten days were used. Three of the mice were undernourished and three clinically healthy (clinical absence of neuropathies) were used as control. For the animals it was offered water with no restrictions and a proteic diet (20% of protein-casein) for the females that generated the group of control constituted by three animals which will be denominated nurtured (N) and a hipoproteic diet (5% of casein) for the females that generate the undernourished group also composed of three animals (D). The sampling was accomplished uniformly, systematic and aleatory, ganglionar volume or volume of the ganglion (Vref), total number of neurons (N), neuronal density (NV), neuronal volume (Vn), density of neuronal volume (Vv). All stereological parameters presented superior values (quite significant). The results suggest the existence of biological differences, in other words, the undernourished animals presented larger neurons and in larger number, but distributed one far from the other, the undernourished ones presented smaller and less neurons, and distributed in a smaller number in the ganglion.

O gânglio celíaco pertence ao plexo celíaco que consiste numa rede de nervos e tecidos de suporte. Os gânglios celíacos, pares, são alongados e situam-se ao longo da face caudal da origem da artéria celíaca. No lado esquerdo o gânglio está ligado por um ramo interganglionar. Ele está intimamente em contato com a superfície da aorta. A inervação autônoma da maioria dos órgãos abdominais faz-se pelo plexo celíaco e estes incluem o pâncreas, fígado, rim, vesícula biliar, epíplon, mesentério, estômago, intestino delgado e porções ascendente e transversa do cólon. A desnutrição protéico-calórica é um dos maiores problemas de saúde pública no mundo, representando nas nações subdesenvolvidas cerca de 40% das causas dos pacientes hospitalizados. Desta forma o estudo da inervação extrínseca do trato gastrintestinal (representada pelo gânglio celíaco) de ratos, sob os aspectos estereológicos e morfométricos, durante estados de desnutrição protéica será fundamental para aferir objetivamente (e não empiricamente) os possíveis danos neuronais ocasionados pela mesma. Ainda, o conhecimento destas informações quantitativas pode ser útil no entendimento da patogênese da neuropatia autonômica hipoproteica e conseqüentemente no seu tratamento, melhorando a qualidade de vida de pacientes animais e humanos. No decorrer deste estudo foram utilizados seis gânglios celíacos esquerdos provenientes de ratos Albinus Wistar neonatos machos provenientes de acasalamento durante um período de sete a dez dias. Três dos ratos eram desnutridos e três clinicamente saudáveis (ausência clínica de neuropatias) que foram usados como controle. Para os animais foram oferecida água sem restrições e uma dieta protéica (20% de proteína-caseina) para as fêmeas que gerarem o grupo controle constituído por três animais que serão denominados nutridos (N) e uma dieta hipoproteica (5% de caseína) para as fêmeas que gerarem o grupo desnutrido também composto por de três animais (D). A amostragem foi realizada de modo uniforme, sistemático e aleatório, volume ganglionar ou volume do gânglio (vg), número total de neurônios (n), densidade neuronal (nv), volume neuronal (vn), densidade de volume neuronal (vv). Todos os parâmetros estereológicos apresentaram valores superiores (bastante significativos). Os resultados sugerem a existência de diferenças biológicas, ou seja, os animais desnutridos apresentavam neurônios maiores e em maior número, mas distribuídos e mais afastados uns dos outros, já os desnutridos possuíam neurônios menores, menos numerosos e distribuídos em um número menor no gânglio. / The celiac ganglion belongs to the celiac plexus which consists of a net of nerves and supportive tissues. The celiac ganglia, even, are alonged and locate along the caudal face of the origin of the celiac artery. On the left side the ganglion is linked by an interganglionar branch. It is intimately in contact with the surface of the aorta. The autonomous innervation of most of the abdominal organs is made by the celiac plexus and these include the pancreas, liver, kidney, gall bladder, epíplon, mesentery, stomach, small intestine and ascendant and transversal portions of the colon. The proteic-caloric undernourishment is one of the largest problems of public health in the world, representing about 40% of the hospitalized patients in underdeveloped nations. Thus, the study of the extrinsic innervation of the gastrointestinal treatment (represented by the celiac ganglion) of rat, under the stereological and morphometric aspects, during states of proteic denutrition will be fundamental to objectively precise (and not empirically) the possible neuronal damages caused by the undernourishment. Still, the knowledge of these quantitative information can be useful in the understanding of the pathogenesis of the autonomous hipoproteic neuropathy and consequently in its treatment, improving the quality of life of patients, animals and humans. During this study, six left celiac ganglions of newborn male rats Albinus Wistar coming from coupling during a period from seven to ten days were used. Three of the mice were undernourished and three clinically healthy (clinical absence of neuropathies) were used as control. For the animals it was offered water with no restrictions and a proteic diet (20% of protein-casein) for the females that generated the group of control constituted by three animals which will be denominated nurtured (N) and a hipoproteic diet (5% of casein) for the females that generate the undernourished group also composed of three animals (D). The sampling was accomplished uniformly, systematic and aleatory, ganglionar volume or volume of the ganglion (Vref), total number of neurons (N), neuronal density (NV), neuronal volume (Vn), density of neuronal volume (Vv). All stereological parameters presented superior values (quite significant). The results suggest the existence of biological differences, in other words, the undernourished animals presented larger neurons and in larger number, but distributed one far from the other, the undernourished ones presented smaller and less neurons, and distributed in a smaller number in the ganglion.

The goal of this project was to examine the visual system of the bonnethead shark (Sphyrna tiburo). The eyes of this shark are located at the extreme lateral ends of a broad, elongated cephalofoil. Better understanding of their visual system may aid in determining the adaptive benefits of their usual head shape. The proposed project examined one specific aspect of their visual system: the organization of retinal ganglion cells and identification of areas of increased resolution. Two experiments were conducted to realize these aims: (1) staining of retinal ganglion cells, to examine their distributional pattern, and (2) retrograde staining of retinal ganglion cells to determine morphology.

Thesis (Ph. D.)--University of Hong Kong, 2007. / Also available online.

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

The vertebrate inner ear is a complex structure responsible for hearing and balance. The inner ear houses sensory epithelia composed of mechanosensory hair cells and non-sensory support cells. Hair cells synapse with neurons of the VIIIth cranial ganglion, the statoacoustic ganglion (SAG), and transmit sensory information to the hindbrain. This dissertation focuses on the development and regulation of both sensory and neuronal cell populations. The sensory epithelium is established by the basic helixloop- helix transcription factor Atoh1. Misexpression of atoh1a in zebrafish results in induction of ectopic sensory epithelia albeit in limited regions of the inner ear. We show that sensory competence of the inner ear can be enhanced by co-activation of fgf8/3 or sox2, genes that normally act in concert with atoh1a. The developing sensory epithelia express several factors that regulate differentiation and maintenance of hair cells. We show that pax5 is differentially expressed in the anterior utricular macula (sensory epithelium). Knockdown of pax5 function results in utricular hair cell death and subsequent loss of vestibular (balance) but not auditory (hearing) defects. SAG neurons are formed normally in these embryos but show disorganized dendrites in the utricle following loss of hair cells. Lastly, we examine the development of SAG. SAG precursors (neuroblasts) are formed in the floor of the ear by another basic helix-loophelix transcription factor neurogenin1 (neurog1). We show that Fgf emanating from the utricular macula specifies neuroblasts, that later delaminate from the otic floor and undergo a phase of proliferation. Neuroblasts then differentiate into bipolar neurons that extend processes to hair cells and targets in the hindbrain. We show evidence that differentiating neurons express fgf5 and regulate further development of the SAG. As more differentiated neurons accumulate, increasing level of Fgf terminates the phase of neuroblast specification. Later on, elevated Fgf stabilizes the transit-amplifying phase and inhibits terminal differentiation. Thus, Fgf signaling regulates SAG development at various stages to ensure that proper number of neurons is generated.

A biomechanical study of intervertebral foraminal narrowing during simulated automotive head-forward and head-turned rear impacts. The objective of this study was to quantify foraminal width, height and area narrowing during head-forward and head-turned rear impacts, and evaluate the potential for nerve root and ganglion impingement. Muscle weakness and paresthesias, documented in whiplash patients, have been associated with neural compression within the cervical intervertebral foramen. Rotated head posture at the time of rear impact has been correlated with increased frequency and severity of chronic radicular symptoms, as compared to facing forward. No studies have quantified dynamic changes in foramen dimensions during head-forward or head-turned rear impacts. Six whole cervical spine specimens with muscle force replication and surrogate head underwent simulated whiplash at 3.5, 5, 6.5 and 8 g, following non-injurious baseline 2 g acceleration. Continuous dynamic foraminal width, height and area narrowing were recorded, and the peaks were determined during each impact and statistically compared to baseline narrowing. During head-forward rear impacts, significant increases (P<0.05) in average peak foraminal width narrowing above baseline were observed at C5-C6 beginning with 3.5 g impact. No significant increases in average peak foraminal height narrowing were observed, while average peak foraminal areas were significantly narrower than baseline at C4-C5 at 3.5, 5 and 6.5 g. During head-turned rear impacts, significant increases (P<0.05) in average peak foraminal width narrowing above baseline of up to 1.8 mm in the left C5-C6 foramen at 8 g were observed. Average peak dynamic foraminal height was significantly narrower than baseline at right C2-C3 foramen at 5 g and 6.5 g, while no significant increases in foraminal area were observed. Extrapolation of the present head-forward rear impact results indicated that the greatest potential for ganglia compression injury was at the lower cervical spine, C5-C6 and C6-C7. The present head-turned rear impact results indicated that the greatest potential ganglia compression injury exists at C5-C6 and C6-C7. Greater potential for ganglia compression injury exists at C3-C4 and C4-C5 due to head-turned rear impact, as compared to head-forward rear impact. Acute ganglia compression may produce a sensitized neural response to repeat compression leading to chronic radiculopathy following head-forward and head-turned rear impacts. Dynamic ganglion or nerve root compression may also lead to chronic radiculopathy.

Thesis (Ph. D.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 110-132).

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

It has been known that light input can affect the emotions of a person. The depressive syndrome Seasonal Affective Disorder (SAD) is an effective example of the power of light in changing the mood of a person. Patients with SAD have recurring depressive episodes that follow seasonal changes, which is due to the changing daylight hours. This phenomenon suggests that there would be receptors in the retina that would not simply be responsible for vision, but also for the regulation of non-visual signals such as emotion. In many animals, projections have been found from the retina to the dorsal raphe nucleus (DRN). This brain region is a serotonergic area and has been found to be involved in the occurrence of depression. As such, the cells in the retina which were found to have projections to the DRN have a high possibility to be involved in emotion regulation. Retinal Ganglion Cells (RGCs) are classified into many types. A specific type known as an alpha cell is suspected to be the DRN-projecting subtype. This study uses Lycium Barbarum Polysaccharide (LBP) as a treatment in protecting the large RGCs from corticosterone (CORT) -induced damage. The aim is to observe if LBP will provide neuroprotection to large sized RGCs damaged by 40mg/kg or 50mg/kg CORT, and hence if LBP can be further investigated as a possible anti-depressant drug. This study observed that although LBP did not reduce large cell deaths, it reduced cell atrophy of the RGCs under high dosage of CORT (50mg/kg). For the same number of cells counted, treatment groups with a high dose CORT injection found more cells over 300μm2 in area than cells under 300μm2. Also, it was found that the temporal quadrants were more sensitive to cell size change than the nasal quadrants, paving way for more in-depth research of the spatial sensitivity to CORT or to LBP. The findings in this study indicate that LBP does indeed have a neuroprotective effect on large RGCs, although this effect is limited and as of yet seems conditional, as this study ignores the effect of CORT and LBP on other large cell properties such as the dendritic field size and the amount of synapses. Further studies are needed to determine the mechanism of the neuroprotective effect of LBP and to determine the exact site of action LBP works on. / published_or_final_version / Anatomy / Master / Master of Medical Sciences