Neurogenetic Heterochrony in Chick, Lizard, and Rat Mapped with Wholemount Acetylcholinesterase and the Prosomeric Model.

In the developing brain, the phenomenon of neurogenesis is manifested heterotopically, that is, much the same neurogenetic steps occur at different places with a different timetable. This is due apparently to early molecular regionalization of the neural tube wall in the anteroposterior and dorsoventral dimensions, in a checkerboard pattern of more or less deformed quadrangular histogenetic areas. Their respective fate is apparently specified by a locally specific combination of active/repressed genes known as "molecular profile." This leads to position-dependent differential control of proliferation, neurogenesis, differentiation, and other aspects, eventually in a heterochronic manner across adjacent areal units with sufficiently different molecular profiles. It is not known how fixed these heterochronic patterns are. We reexamined here comparatively early patterns of forebrain and hindbrain neurogenesis in a lizard (Lacerta gallotia galloti), a bird (the chick), and a mammal (the rat), as demonstrated by activation of acetylcholinesterase (AChE). This is an early marker of postmitotic neurons, which leaves unlabeled the neuroepithelial ventricular cells, so that we can examine cleared wholemounts of the reacted brains to have a birds-eye view of the emergent neuronal pattern at each stage. There is overall heterochrony between the basal and alar plates of the brain, a known fact, but, remarkably, heterochrony occurs even within the precocious basal plate among its final anteroposterior neuromeric subdivisions and their internal microzonal subdivisions. Some neuromeric units or microzones are precocious, while others follow suit without any specific spatial order or gradient; other similar neuromeric units remain retarded in the midst of quite advanced neighbors, though they do produce similar neurogenetic patterns at later stages. It was found that some details of such neuromeric heterochrony are species-specific, possibly related to differential morphogenetic properties. Given the molecular causal underpinning of the updated prosomeric model used here for interpretation, we comment on the close correlation between some genetic patterns and the observed AChE differentiation patterns.

Examining the immune signatures of SARS-CoV-2 infection in pregnancy and the impact on neurodevelopment: Protocol of the SIGNATURE longitudinal study.

The COVID-19 pandemic represents a valuable opportunity to carry out cohort studies that allow us to advance our knowledge on pathophysiological mechanisms of neuropsychiatric diseases. One of these opportunities is the study of the relationships between inflammation, brain development and an increased risk of suffering neuropsychiatric disorders. Based on the hypothesis that neuroinflammation during early stages of life is associated with neurodevelopmental disorders and confers a greater risk of developing neuropsychiatric disorders, we propose a cohort study of SARS-CoV-2-infected pregnant women and their newborns. The main objective of SIGNATURE project is to explore how the presence of prenatal SARS-CoV-2 infection and other non-infectious stressors generates an abnormal inflammatory activity in the newborn. The cohort of women during the COVID-19 pandemic will be psychological and biological monitored during their pregnancy, delivery, childbirth and postpartum. The biological information of the umbilical cord (foetus blood) and peripheral blood from the mother will be obtained after childbirth. These samples and the clinical characterisation of the cohort of mothers and newborns, are tremendously valuable at this time. This is a protocol report and no analyses have been conducted yet, being currently at, our study is in the recruitment process step. At the time of this publication, we have identified 1,060 SARS-CoV-2 infected mothers and all have already given birth. From the total of identified mothers, we have recruited 537 SARS-COV-2 infected women and all of them have completed the mental health assessment during pregnancy. We have collected biological samples from 119 mothers and babies. Additionally, we have recruited 390 non-infected pregnant women.

Quail-chick grafting experiments corroborate that Tbr1-positive eminential prethalamic neurons migrate along three streams into hypothalamus, subpallium and septocommissural areas.

The prethalamic eminence (PThE), a diencephalic caudal neighbor of the telencephalon and alar hypothalamus, is frequently described in mammals and birds as a transient embryonic structure, undetectable in the adult brain. Based on descriptive developmental analysis of Tbr1 gene brain expression in chick embryos, we previously reported that three migratory cellular streams exit the PThE rostralward, targeting multiple sites in the hypothalamus, subpallium and septocommissural area, where eminential cells form distinct nuclei or disperse populations. These conclusions needed experimental corroboration. In this work, we used the homotopic quail-chick chimeric grafting procedure at stages HH10/HH11 to demonstrate by fate-mapping the three predicted tangential migration streams. Some chimeric brains were processed for Tbr1 in situ hybridization, for correlation with our previous approach. Evidence supporting all three postulated migration streams is presented. The results suggested a slight heterochrony among the juxtapeduncular (first), the peripeduncular (next), and the eminentio-septal (last) streams, each of which followed differential routes. A possible effect of such heterochrony on the differential selection of medial to lateral habenular hodologic targets by the migrated neurons is discussed.

Longitudinal developmental analysis of prethalamic eminence derivatives in the chick by mapping of Tbr1 in situ expression.

The prethalamic eminence (PThE) is the most dorsal subdomain of the prethalamus, which corresponds to prosomere 3 (p3) in the prosomeric model for vertebrate forebrain development. In mammalian and avian embryos, the PThE can be delimited from other prethalamic areas by its lack of Dlx gene expression, as well as by its expression of glutamatergic-related genes such as Pax6, Tbr2 and Tbr1. Several studies in mouse embryos postulate the PThE as a source of migratory neurons that populate given telencephalic centers. Concerning the avian PThE, it is visible at early embryonic stages as a compact primordium, but its morphology becomes cryptic at perinatal stages, so that its developmental course and fate are largely unknown. In this report, we characterize in detail the ontogeny of the chicken PThE from 5 to 15 days of development, according to morphological criteria, and using Tbr1 as a molecular marker for this structure and its migratory cells. We show that initially the PThE contacts rostrally the medial pallium, the pallial amygdala and the paraventricular hypothalamic alar domain. Approximately from embryonic day 6 onwards, the PThE becomes progressively reduced in size and cell content due to massive tangential migration of many of its neuronal derivatives towards nearby subpallial and hypothalamic regions. Our analysis supports that these migratory neurons from the avian PThE target telencephalic centers such as the commissural septal nuclei, as previously described in mammals, but also the diagonal band and preoptic areas, and hypothalamic structures in the paraventricular hypothalamic area.

Continuing education: preparing patients to choose a renal replacement therapy.

BACKGROUND: Patients with progressive chronic kidney disease face a series of treatment decisions that will impact the quality of life of themselves and their family. Renal replacement therapy option education (RRTOE), generally provided by nurses, is recommended by international guidelines OBJECTIVES: To provide nurses with advice and guidance on running RRTOE. DESIGN: A consensus conference. PARTICIPANTS: Four nurses, 5 nephrologists and 1 clinical psychologist (9 renal units; 6 European countries) from units that had extensive experience in RRTOE or were performing research in this field. APPROACH: Experts brainstormed and discussed quality standards for the education team, processes, content/topics, media/material/funding and quality measurements for RRTOE. RESULTS: Conclusions and recommendations from these discussions that are particularly pertinent to nurses are presented in this paper. CONCLUSIONS: Through careful planning and smooth interdisciplinary cooperation, it is possible to implement an education and support programme that helps patients choose a form of RRT that is most suited to their needs. This may result in benefits in quality of life and clinical outcomes. APPLICATION TO PRACTICE: There are large differences between renal units in terms of resources available and the demographics of the catchment area. Therefore, nurses should carefully consider how best to adapt the advice offered here to their own situation. Throughout this process, it is crucial to keep in mind the ultimate goal - providing patients with the knowledge and skill to make a modality choice that will enhance their quality of life to the greatest degree.

Quality standards for predialysis education: results from a consensus conference.

This position statement was compiled following an expert meeting in March 2013, Zurich, Switzerland. Attendees were invited from a spread of European renal units with established and respected renal replacement therapy option education programmes. Discussions centred around optimal ways of creating an education team, setting realistic and meaningful objectives for patient education, and assessing the quality of education delivered.

Predialysis education in practice: a questionnaire survey of centres with established programmes.

BACKGROUND: There is growing evidence that renal replacement therapy option education (RRTOE) can result in enhanced quality of life, improved clinical outcomes, and reduced health care costs. However, there is still no detailed guidance on the optimal way to run such programmes. To help address this knowledge gap, an expert meeting was held in March 2013 to formulate a position statement on optimal ways to run RRTOE. Experts were selected from units that had extensive experience in RRTOE or were performing research in this field. Before the meeting, experts completed a pilot questionnaire on RRTOE in their own units. They also prepared feedback on how to modify this questionnaire for a large-scale study. METHODS: A pilot, web-based questionnaire was used to obtain information on: the renal unit and patients, the education team, RRTOE processes and content, how quality is assessed, and funding. RESULTS: Four nurses, 5 nephrologists and 1 clinical psychologist (9 renal units; 6 EU countries) participated. Nurses were almost always responsible for organising RRTOE. Nephrologists spent 7.5% (median) of their time on RRTOE. Education for the patient and family began several months before dialysis or according to disease progression. Key topics such as the 'impact of the disease' were covered by every unit, but only a few units described all dialysis modalities. Visits to the unit were almost always arranged. Materials came in a wide variety of forms and from a wide range of sources. Group education sessions were used in 3/9 centres. Expectations on the timing of patients' decisions on modality and permanent access differed substantially between centres. Common quality assurance measures were: patient satisfaction, course attendance, updated materials. Only 1 unit had a dedicated budget. CONCLUSIONS: There were substantial variations in how RRTOE is run between the units. A modified version of this questionnaire will be used to assess RRTOE at a European level.

Endothelial NT-3 delivered by vasculature and CSF promotes quiescence of subependymal neural stem cells through nitric oxide induction.

Interactions of adult neural stem cells (NSCs) with supportive vasculature appear critical for their maintenance and function, although the molecular details are still under investigation. Neurotrophin (NT)-3 belongs to the NT family of trophic factors, best known for their effects in promoting neuronal survival. Here we show that NT-3 produced and secreted by endothelial cells of brain and choroid plexus capillaries is required for the quiescence and long-term maintenance of NSCs in the mouse subependymal niche. Uptake of NT-3 from irrigating vasculature and cerebrospinal fluid (CSF) induces the rapid phosphorylation of endothelial nitric oxide (NO) synthase present in the NSCs, leading to the production of NO, which subsequently acts as a cytostatic factor. Our results identify a novel interaction between stem cells and vasculature/CSF compartments that is mediated by an unprecedented role of a neurotrophin and indicate that stem cells can regulate their own quiescence in response to endothelium-secreted molecules.

Enzymatic evidence for the key role of arginine in nitrogen translocation by arbuscular mycorrhizal fungi.

Key enzymes of the urea cycle and (15)N-labeling patterns of arginine (Arg) were measured to elucidate the involvement of Arg in nitrogen translocation by arbuscular mycorrhizal (AM) fungi. Mycorrhiza was established between transformed carrot (Daucus carota) roots and Glomus intraradices in two-compartment petri dishes and three ammonium levels were supplied to the compartment containing the extraradical mycelium (ERM), but no roots. Time courses of specific enzyme activity were obtained for glutamine synthetase, argininosuccinate synthetase, arginase, and urease in the ERM and AM roots. (15)NH(4)(+) was used to follow the dynamics of nitrogen incorporation into and turnover of Arg. Both the absence of external nitrogen and the presence of L-norvaline, an inhibitor of Arg synthesis, prevented the synthesis of Arg in the ERM and resulted in decreased activity of arginase and urease in the AM root. The catabolic activity of the urea cycle in the roots therefore depends on Arg translocation from the ERM. (15)N labeling of Arg in the ERM was very fast and analysis of its time course and isotopomer pattern allowed estimation of the translocation rate of Arg along the mycelium as 0.13 microg Arg mg(-1) fresh weight h(-1). The results highlight the synchronization of the spatially separated reactions involved in the anabolic and catabolic arms of the urea cycle. This synchronization is a prerequisite for Arg to be a key component in nitrogen translocation in the AM mycelium.

The midbrain of sauropsides shares a common subdivision pattern defined by embryonic radial glia.

In a previous study of the embryonic midbrain radial glia in a lizard, we observed that these cells define boundaries and regional subdivisions in a pattern that largely supports the adult model [C. Diaz, C. Yanes, C.M feminine. Trujillo, L. Puelles, Cytoarchitectonic subdivisions in the subtectal midbrain of the lizard Gallotia galloti, J. Neurocytol. 29 (2000) 569-593]. With the goal to check whether the midbrain of chick embryos has a similar pattern, we examined the radial glia distribution in this model using a lipophilic dye (DiI) injected intraventriculary. As in the lizard, chick radial glia distribution and fasciculation defines at least six regional subdivisions in the midbrain, five of which are alar and one basal. Each territory corresponds to a particular cytoarchitectonic area, recognized previously. The rostral mesencephalic limit (m/d) is underlined in the alar zone by a thick band of fasciculated radial glia intercalated between the griseum tectale and the posterior commissure. A fasciculated radial glia band also defines the caudal mesencephalic limit (m/r) across the alar and basal zones. These glial specializations, not described previously in the chick, give physical entity to the limits deduced from gene expression studies and suggested by descriptive cytoarchitectonic analysis. We conclude that the midbrain of sauropsides shares a common subdivision pattern co-defined by radial glia arrangements.

The rostral and caudal boundaries of the diencephalon.

Knowledge of nature and features of the boundaries between the main neural regions seems to be essential to understand the rules of brain regionalization. On the light of several current and classical criteria used to define cerebral boundaries, we examine the features of the places recognized as rostral and caudal boundaries in the developing diencephalon and provide new images about the glial features of these boundaries. One demonstrated property of some embryonic boundaries is the prevention of the crossing cells in the early ventricular zone (clonal restriction), while the intermediate zone seems to lack it. Data available so far indicate that the early boundary between diencephalon and mesencephalon (d/m) is a clonal restriction limit, but not between diencephalon and telencephalon (d/t). Later, while diencephalic nuclei form, cellular dispersion does not occur through the alar part of d/m, but it achieves in the corresponding d/t alar portion. The relationship between origin, migration, and cell-type specification of neural cells is being the object of special attention in the telencephalon, where specific cellular fenotipes can migrate to distant regions following non-radial routes. Such is the case of most GABAergic interneurons of avian and mammalian pallium and oligodendrocytes of the forebrain. In this regard, little attention has been devoted to the diencephalon, where this type of migration, specially those through the rostral boundary, has been reported by different authors. We introduce increasing evidence about non-conventional neuronal migration in the developing diencephalon and compare the reported migratory behavior with respect to both boundaries.

Radial glia defines boundaries and subdivisions in the embryonic midbrain of the lizard Gallotia galloti.

We have studied the organization of the midbrain radial glia in embryos of Gallotia galloti using the fluorescent lipophilic dye 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine perchlorate (DiI) and the antibodies H5 and RC2. Our goal was to verify if the radial glia takes part in the midbrain boundaries formation and if it defines different zones. Our exam reveals two clear limits, anterior or mesencephalic-diencephalic (m/d) and posterior or mesencephalic-rhombencephalic (m/r), that can be defined as the borders where the midbrain radial glia processes end. Moreover, fasciculate radial glia processes characterize these limits totally or partially. They coincide with gene expression limits and with cytoarchitectonic limits defined by other criteria. Six different subdivisions, five alar and one basal, can be defined according to radial glia distribution, fasciculation, and immunohistochemical features. The ventral part of the alar region is defined by an RC2-positive bundle of radial glial cells. This bundle supposes a trustworthy landmark to point out the tectal/tegmental boundary. We hypothesize that this pattern of midbrain radial glia represents a basic model in amniota.

Different nitrogen sources modulate activity but not expression of glutamine synthetase in arbuscular mycorrhizal fungi.

Glutamine synthetase (GS) is a central enzyme of nitrogen metabolism that allows assimilation of nitrogen and biosynthesis of glutamine. We isolated the cDNA encoding GS from two arbuscular mycorrhizal fungi, Glomus mosseae (GmGln1) and Glomus intraradices (GiGln1). The deduced protein orthologues have a high degree of similarity (92%) with each other as well as with GSs from other fungi. GmGln1 was constitutively expressed during all stages of the fungal life cycle, i.e., spore germination, intraradical and extraradical mycelium. Feeding experiments with different nitrogen sources did not induce any change in the mRNA level of both genes independent of the symbiotic status of the fungus. However, GS activity of extraradical hypahe in G. intraradices was considerably modulated in response to different nitrogen sources. Thus, in a N re-supplementation time-course experiment, GS activity responded quickly to addition of nitrate, ammonium or glutamine. Re-feeding with ammonium produced a general increase in GS activity when compared with hyphae grown in nitrate as a sole N source.

La educación médica asistida por computadora / Medical training supported by computers

En educación las computadoras, los videos y la televisión por cable resultan de una importancia que se incrementa día a día. La palabra ha sido tradicionalment el método de comunicación de información desde hace tiempos inmemoriales. Sin emabargo con la aparición del televisor entre 1923 y 1933 y su subsecuente uso en la educación en los años siguientes a la Segunda Guerra Mundial, las instituciones educativas han incrementado la utilización de tecnología para transmitir información. Algunos de los problemas identificados en el presente artículo relacionados con el uso de computadoras para la educación, incluyen, la estandarización del equipo y los programas, dificultades con la impresión de la información en formato gráfico, etc. Algunas de las ventajas identificadas son, la información esta disponible a través de las computadoras a todos los estudiantes, este método de enseñanza es más económico y no compromete la calidad del mismo. Con el advenimiento de esta nueva froma de transmisión de información se ha expresado algunas preocupaciones acerca de la "deshumanización" de la educación. El artículo analiza como las computadoras y la tecnología relacionada puede ser útil en la educación, sin embargo el contacto humano es aún parte esencial de la educación, además de que la eficacia de la computadora depende de la forma como es empleada por el educador.

Estudio prospectivo de efectos secundarios asociados con la administración de verteporfin (visudyne) por vía endovenosa / Prospective study of side effects Associated with intravenous administration of verteporfin (visudyne 0) for the treatment of age-related macular degeneration

La degeneración macular relacionada con la edad (DMRE) es la primera causa de ceguera en personas mayores de 50 años en el mundo occidental. Su etiología es aún discutible y la modalidad terapéutica más esperanzadora (terapia fotodinámica) involucra la utilización intravenosa de un compuesto fotosensible (verteporfin () que siendo activado mediante una luz de longitud de onda específica, produce lesión vascular y muerte celular directa de la zona a tratar. El objetivo de esta investigación es determinar los eventos adversos asociados con la administración de verteporfin (Visudyne) por vía endovenosa. Para tal fin se evaluaron 104 pacientes sometidos a terapia fotodinámica a quienes se les aplicó un cuestionario Ad Hoc determinándose que solo el 2,88 por ciento de la muestra presentó complicaciones. En conclusión la administración de verteporfin por vía endovenosa es un procedimiento seguro, siempre que se cumpla las normas de seguridad previstas para la administración del medicamento

Continuity and discontinuity of the radial scaffolding in the forebrain of a lizard embryo.

We have used ventricular injections of the fluorescent carbocyanine dye DiI (Molecular Probes, Eugene, OR, USA) to demonstrate the scaffolding of the radial ventricular cells in the embryonic forebrain of lizards. The results reveal changes of density, orientation, or thickness of the radial processes between adjacent regions. On the whole, they support the idea that the hypothalamus together with the telencephalic stalk and the telencephalic hemispheres make up the anterior region of the neural tube or secondary prosencephalon, as proposed by the prosomeric model. In contrast, the thalamic eminence seems part of the diencephalon.

Profilaxis antibiótica por vía oral en cirugía de colon

Se asignó aleatoriamente a un total de 169 pacientes sometidos a cirugía colorrectal a un programa de profilaxis antibiótica oral con gentamicina ó cirpofloxacina, administrándose dosis en uno o tres días respectivamente. Veintiocho pacientes (17 por ciento) presentaron infecciones postoperatorias de la herida operatoria. La proporción de paientes con infección de la herida y otras complicaicones infecciosas fue significativamente inferior (p< 0.02) en aquellos pacientes que recibieron ciprofloxacina. La cobertura de tres días no fue superior a la de un día. La cirpofloxacina por vía oral para la profilaxis antibiótica en cirugía colónica puede ofrecer ventajas en cuanto a eficacia y facilidad de adminsitración en comparación con los antibióticos por vía parenteral

Prevalencia de la parálisis cerebral en el Centro de Rehabilitación Médica No, 1 Innfa en la ciudad del niño Conocoto / PreValencia of the cerebral paralysis in the Medical Disciplinary centre no 1. innfa in the city of the Conocoto boy

Realizamos el estudio de la prevalencia e incidencia de la parálisis cerebral infantil en el Centro de Rehabilitación Médica No. 1 Innfa y de sus formas clínicas. Establecemos que la prevalencia de parálisis cerebral infantil es de 2,3 x 100 y la incidencia de 2,08 x 100 en la población atendida en ese período. El tipo prevalente de parálisis cerebral es el Piramidal 1,60 por cientp y su variedad clínica más frecuente es la parálisis cerebral Tetraparética con una prevalencia de 1,28 por ciento. El sexo masculino es más frecuentemente afectado, cuyo prevalencia es de 1,36 x 100 en relación al femenino que es de 1,0 x 100. La prematurez, la asfixia y la meningitis siguen siendo los factores etiológicos perinatales más frecuentes y su diagnóstico se hace generalmente después del año de edad...

Neuronal typology of the thalamic area triangularis of Gallotia galloti (reptilia, sauria).

In a Golgi study of the area triangularis (AT), a rostral nucleus of the ventral thalamus of Gallotia galloti, we have identified four major neuronal types on the basis of their morphological characteristics: medium-sized fusiforms with two processes, medium-sized fusiforms with three or four processes, small bipolars, and small and medium-sized multipolars. These neurons are characterized by a simple morphology and radial arrangement. Cell size varies from small to medium, and all axons project laterally. These characteristics distinguish AT neurons from those of neighboring nuclei. In addition, we found some evidence of differential topographic distribution of each neuronal type within the nucleus. Medium-sized fusiform neurons with two processes are located in the most ventral part, where they constitute the ventral nuclear limit. Small multipolar neurons prevail in the dorsal and ventromedial parts, and in the rest of the nucleus medium-sized neurons, including both fusiform with three or four processes and multipolar types, are normally found. Finally, we discuss a putative homology of the reptilian AT with a part of the mammalian zona incerta.

Neuronal differentiation in the thalamic area triangularis of a lizard.

Development of neurons in the area triangularis of Gallotia galloti was investigated in Golgi-impregnated brain tissue. Four major neuronal types present in adults were found to originate from two migratory neuroblast types, which were followed from embryonic stage S.32. One type has a thick main medial process, whereas the second type has a long main lateral process. As they migrate toward the periphery of the nucleus, morphological characteristics of maturation appear, including growth cones, filopodia, and outgrowth of axons. Neuroblasts with a main lateral process differentiate into two immature neuronal types, bipolars and pyramidals, observed at S.33 and thereafter. The neuroblasts with a main medial process undergo some somatic translocation through a transitory tangential shaft. Then they develop into monopolar immature forms with a long varicose medial, process, appearing from S.36. onward. Immature bipolar neurons do not experience great changes in their dendritic arborization during development to the adult stage, but pyramidals and monopolars undergo a rapid development of the dendritic tree after S.36. By S.38 archetypes of adult neuronal forms are established. Hairlike appendages first appear on neurons at S.36 They decrease suddenly in S.38 and then proliferate in S.39 when spines first appear. Around the time of hatching, the hairlike appendages begin to disappear and spines become established. Reduction of spines occurs after hatching and continues to the adult stage. Possible influences of several external factors on neuronal maturation are discussed.