1,722,011 research outputs found
VIP-like and GFAP-like immunoreactivities in the chicken brain stem. I. The medulla.
No full textThe aim of the present research is to study the development of spinal ganglia implanted onto chorio-allantoic membrane (CAM), where they are supplied by 'foreign', extraembryonic vessels. Small blocks including a segment of the neural tube and 4 pairs of somites were isolated from the brachial or thoracic or lumbar region (neuromeres C13 - T1 or T3 - T6 or L1 - L4) of thirty 3-day donor chick embryos and grafted on the CAM of as many 10-day host chick embryos. At regular time intervals after grafting, the implants were fixed, embedded in paraffin, serially cross-sectioned and stained. The preliminary results are similar for the ganglia from the 3 regions: they seem to indicate that in the spinal ganglia grafted on the CAM the developing blood vessels do not exert any morphogenetic influence on the substratum; this corroborates results from previous researches (2) on the normally 'in situ' developing ganglia. It is now the author purpose to submit to a careful analysis a datum from the present research: namely, the earlier appearance of the endoganglionic vessels in the brachial and lumbar grafted ganglia than in the thoracic ones
Repurposing opportunities for Parkinson’s disease therapies
No full textParkinson’s disease (PD) is an adult neurodegenerative disease affecting approximately 1% of the population over 65 years and 4%-5% over 80 years of age. The rate of disease progression is widely variable among subjects. PD is primarily a sporadic disease (about 90% of cases) (Rodriguez et al. 2015) while about 10% correspond to purely familial forms and have monogenic basis (Lesage and Brice 2009; Spataro et al. 2015). However, even within the sporadic form, some patients report genetic susceptibility factors, which are responsible for increasing the risk of developing PD. For instance, heterozygous mutations in GBA1 gene, encoding for the lysosomal enzyme glucocerebrosidase, have been detected in 5%-10% of sporadic PD patients (Sidransky et al. 2009; Schapira and Gegg 2013), thereby representing the most critical genetic risk factor in PD identified to date. PD is caused by the slow and progressive degeneration of dopaminergic neurons within the substantia nigra pars compacta (SNc); this leads to dopamine (DA) depletion of the corpus striatum followed by profound functional alterations of the basal ganglia circuitry, which controls the correct execution of voluntary movements (Blandini et al. 2000). In fact, PD is typically associated with motor symptoms, such as resting tremor, bradykinesia, slowness of movements, and postural instability. However, nonmotor symptoms are also present in PD patients and often precede the onset of classical motor manifestations (Olanow and Obeso 2012). These symptoms include olfactory impairment, sleep disorders, urogenital and gastrointestinal dysfunctions, and cognitive and psychiatric disturbances (Ferrer et al. 2012). Diagnosis of PD is performed on a clinical basis and can be confirmed only postmortem in patient brains, with the evidence of massive neuronal loss in the SNc and the detection of Lewy bodies (LBs), the main hallmark of PD. LBs are insoluble aggregates mainly containing α-synuclein, the protein encoded by SNCA or PARK1/PARK4 gene, a genetic locus linked to familial PD (Xu et al. 2015), as well as phosphorylated and poly-ubiquitinated proteins. Several lines of evidence clearly suggest that overexpression and oligomerization of α-synuclein are directly related to the toxicity in the nigrostriatal areas (Masliah et al. 2000; Hayashita-Kinoh et al. 2006). The presence of LBs is not restricted to SNc and other cerebral regions (Von Bohlen und Halbach et al. 2004); they also spread in the spinal cord, in the vagus nerve, and in peripheral organs such as the gastrointestinal tract (Beach et al. 2010), confirming that PD is a complex and diffuse disease, affecting not only the brai
Double-labelling data on somatostatin-like and tyrosine-hydroxylase-like immunoreactivities in chick embryo brain stem. I. Pons and mesencephalon.
No full textWith the aim of investigating some factors and mechanisms of the chicken brain development, the same thick sections of brain stems from twelve E13-to-E21-aged chick embryos were sequentially tested with a rabbit anti-Somatostatin antiserum, using a PAP-DAB technique, and with anti-tyrosine hydroxylase (-TH) monoclonal antibodies, using an indirect immuno-fluorescence technique. As regards the pons and mesencephalon, the following main results were obtained. At E21 almost the same distribution of the TH-like immunoreactivity (ir) as at E13 was observed. Neuroblasts in a central, relatively wide region of mesencephalic tegmentum and in the central portion of the pons showed TH-like ir. A co-localization of the 2 immunoreactivities was detected only at E18, within some neuroblasts of the mesencephalic and pontine regions with TH-like ir. It is possible that this transitory co-localization plays a role in the development of the pons and mesencephalon of this species
Neuron populations of the human cerebellar cortex containing vasoactive intestinal polypeptide. A preliminary report
No full textA further update on the role of excitotoxicity in the pathogenesis of Parkinson’s disease
No full textIncreased levels of extracellular glutamate and hyperactivation of glutamatergic receptors in the basal ganglia trigger a critical cascade of events involving both intracellular pathways and cell-to-cell interactions that affect cell viability and promote neuronal death. The ensemble of these glutamate-triggered events is responsible for excitotoxicity, a phenomenon involved in several pathological conditions affecting the central nervous system, including a neurodegenerative disease such as Parkinson’s disease (PD). PD is an age-related disorder caused by the degeneration of dopaminergic neurons within the substantia nigra pars compacta, with a miscellaneous pathogenic background. Glutamate-mediated excitotoxicity may be involved in a lethal vicious cycle, which critically contributes to the exacerbation of nigrostriatal degeneration in PD. Since excitotoxicity is a glutamate-receptormediated phenomenon, growing interest and work have been dedicated to the research for modulators of glutamate neurotransmission that might enable new therapeutic interventions to slow down the neurodegenerative process and ameliorate PD motor symptoms
VIP-like and GFAP-like immunoreactivities in the chicken brain stem. I. The medulla.
No full textAn immunocytochemical analysis was performed on the chicken medulla according to the PAP-DAB procedure, to study the distribution here of the neurons reacting to anti-VIP antibodies and the gliocytes reacting to anti-GFAP antibodies. Positive and negative controls were carried out in both the immunoreactions. The findings seem to indicate that more numerous VIP-immunoreactive neurons are located in the chicken than in the rat or mouse medulla, mainly in its intermediate 1/3, that VIP-immunoreactive fibres connect the medullar group of immunoreactive neurons with at least the first three cervical neuromeres, and confirm also for the chicken medulla, as already reported in other species by various researchers, the close relation of some VIP-immunoreactive neuronal processes with the small blood vessel walls, and the distribution of the GFAP-immunoreactive gliocytes
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
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