A study of the properties, morphogenetic potencies and prospective fate of outer and inner layers of ectodermal and chordamesodermal regions during gastrulation, in various Anuran amphibians

Development ◽  
1983 ◽  
Vol 75 (1) ◽  
pp. 67-86
Author(s):  
T. A. Dettlaff

In both the ectodermal and the chordamesodermal regions of Anuran embryos, the outer layer of cells possesses epithelial properties and has the same restricted morphogenetic potencies. It is thus interchangeable between the regions, capable of epiboly and, when underlain by notochord material, of the formation of bottle-shaped cells as at the blastoporal groove, and invagination. When taken from the chordamesoderm region, this outer layer has no inducing effect on the ectoderm of the early gastrula. In normal development the outer layer of the neural plate takes an active part in forming the neural tube cavity. It gives rise to the neuroepithelial roof of the diencephalon and medulla oblongata and, when underlain by neuroblasts that develop from the inner cell layers, to ependymal cells of the brain wall. The outer layer of the notochord material is included in the epithelial layer underlying the roof of the gastrocoel - the hypochordal plate. The inner layers of these regions consist of loosely arranged cells and normally have no epithelial properties although, when taken from the ectoderm region, they may acquire such properties upon long-term contact with the environment. However they have wide morphogenetic potencies; the differences in these potencies between cells taken from the various presumptive regions being less than the differences between outer and inner cell layers in each region. Maps are provided which show the arrangement of presumptive rudiments in the ectoderm and chordamesoderm on sagittal sections through Bombina bombina embryos in early and late gastrulation.

2020 ◽  
Author(s):  
Katrin Mangold ◽  
Jan Mašek ◽  
Jingyan He ◽  
Urban Lendahl ◽  
Elaine Fuchs ◽  
...  

ABSTRACTGene variants associated with disease are efficiently identified with whole genome sequencing or GWAS, but validation in vivo lags behind. We developed NEPTUNE (neural plate targeting by in utero nanoinjection), to rapidly and flexibly introduce gene expression-modifying viruses to the embryonic murine neural plate prior to neurulation, to target the future adult nervous system. Stable integration in >95% of cells in the brain enabled long-term gain- or loss-of-function, and conditional expression was achieved using mini-promotors for cell types of interest. Using NEPTUNE, we silenced Sptbn2, a gene associated with Spinocerebellar ataxia type 5 (SCA5) in humans. Silencing of Sptbn2 induced severe neural tube defects and embryo resorption, suggesting that SPTBN2 in-frame and missense deletions in SCA5 reflect hypomorphic or neomorphic functions, not loss of function. In conclusion, NEPTUNE offers a novel, rapid and cost-effective technique to test gene function in brain development, and can reveal loss of function phenotypes incompatible with life.


Author(s):  
E. D. Belousova

Febrile seizures are the age-dependent and predictively favorable condition, which is observed in children under 6 years. All febrile seizures are divided into simple (2/3 of all cases), complex and febrile status. Complicated seizuresinclude attacks with focalsymptoms, prolonged and recurring throughout the day. Simple febrile seizures are short, generalized, not repeated. Simple seizures do not harm the child’s neuropsychic development, they do not transform into epilepsy, and do not need chronic prescription of anticonvulsant therapy. A child with normal development and simple febrile seizures does not need an obligatory EEG and MRI of the brain. All the patients of 18 months old or less with the first episode of febrile seizures need to be hospitalized. The risk of recurrence of seizures and their transformation into epilepsy is higher in a child with complex seizures. There is a small group of children with prolonged seizures and / or febrile status, often with neuropsychiatric developmental delay, which needs to be monitored by a neurologist and further examination. Sometimes doctor prescribes long-term anticonvulsant therapy for the children of this group. Febrile seizures can be prevented with special dosage of anticonvulsant drugs quickly reaching a therapeutic concentration in the child’s brain. Febrile seizures are not a contraindication to vaccination and revaccination, attention should be paid in case of DTP vaccination in children with repeated prolonged seizures and / or febrile status.Conflict of interest: The author of this article confirmed the lack of conflict of interest and financial support, which should be reported.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3739-3739
Author(s):  
Yasuyuki Miyake ◽  
Yasushi Okoshi ◽  
Takayuki Machino ◽  
Shigeru Chiba

Abstract Abstract 3739 Poster Board III-675 Background Primary central nervous system lymphoma (PCNSL) is almost exclusively CD20-positive non-Hodgkin lymphoma (NHL). Although rituximab (R) is widely used for CD20-positive NHL, it is not considered to reach brain lesions effectively beyond the blood brain barrier. Intraventricule administration (ivt) of R is reported to be effective in meningeal lymphoma but the effect on lesions in the brain parenchyma seems to be limited. Recently, a case of refractory PCNSL that was successfully treated with ivt of R with autologous serum was reported (Takami A, et al. Cancer Science, 2006). Because the cerebrospinal fluid does not contain complements which exists in the serum, induction of complement-dependent cytotoxicity by ivt of R plus autoserum was speculated. To investigate this effect, we developed an animal treatment model of CNSL. Materials and methods Raji, CD20-positive Burkitt lymphoma cell line, was inoculated into the deep frontal lobe of the brain of 8-week old F344 (nru-/nru-) nude rats, using brain stereotaxic apparatus. At the same time, a cannula was placed into the ipsilateral lateral ventricle. After several days, R or control immunoglobulin (cIg), plus human serum or saline, was administrated into the lateral ventricle. Results The brain was extracted 24 hours after the last administration and frozen section was made. Human CD20-positive Raji cell tumor was also positively stained with FITC-conjugated anti-human IgG antibody when R but not cIg was administrated. Consequently, R in the lateral ventricle was considered to penetrate ependymal cells and brain parenchyma, and bound to lymphoma cells. Next, these rats were treated with ivt of R plus serum (R + Serum), cIg plus serum (cIg + Serum), or R plus saline (R + saline). These were administrated once a day from day 5 to day 9 after inoculation of Raji, and then survival was monitored. When an obvious weakness, such as marked and consecutively loss of activity or weight, was observed, these rats were euthanized and this is defined as dead day. In each case, the brain was extirpated and examined whether lymphoma existed or not. Death without lymphoma or from technical problem was excluded from the analysis. Survival of each group was analyzed by Kaplan-Meier method and log-lank test. R + Serum group had longer survival than cIg + Serum (p = 0.049). Long-term survivors were only seen in R + Serum and this group seemed to be superior to R + saline but statistical difference was not detected (p = 0.083). There were no difference between cIg + Serum and R + saline (p =0.382) and neither group had long-term survivor. Conclusion The possibility of novel treatment of CNSL with ivt of R and autoserum was shown in the rat CNSL model. To confirm this approach, clinical trials are warranted. Disclosures: No relevant conflicts of interest to declare.


2021 ◽  
Vol 3 (Supplement_6) ◽  
pp. vi1-vi1
Author(s):  
Yukiko Gotoh

Abstract Quiescent neural stem cells (NSCs) in the adult mouse brain are the source of neurogenesis that regulates innate and adaptive behaviors. Adult NSCs in the subventricular zone (SVZ) are derived from a subpopulation of embryonic neural stem-progenitor cells (NPCs) that is characterized by a slower cell cycle relative to the more abundant rapid cycling NPCs that build the brain. We have previously shown that slow cell cycle can cause the establishment of adult NSCs at the SVZ, although the underlying mechanism remains unknown. We found that Notch and an effector Hey1 form a module that is upregulated by cell cycle arrest in slowly dividing NPCs. In contrast to the oscillatory expression of the Notch effectors Hes1 and Hes5 in fast cycling progenitors, Hey1 displays a non-oscillatory stationary expression pattern and contributes to the long-term maintenance of NSCs. These findings reveal a novel division of labor in Notch effectors where cell cycle rate biases effector selection and cell fate. I will also discuss the heterogeneity of slowly dividing embryonic NPCs and the lineage relationship between adult NSCs and ependymal cells, which together form the niche for adult neurogenesis at the SVZ.


1947 ◽  
Vol 24 (1-2) ◽  
pp. 145-183 ◽  
Author(s):  
P. D. NIEUWKOOP

1. With the aseptic operation method of Woerdeman (1930) it is possible to rear duplicitas larvae, formed after grafting of the dorsal blastoporal lip in the place of the ventral one at the early gastrula stage (Spemann, 1918), till an age of about 4 weeks, a time at which they have completely consumed their yolk material. 2. Various forces acting in the normal development and in the development of the duplicitas larvae are discussed in connexion with the external form and the internal organization of the latter. 3. The sources of errors in the method of graphic reconstruction of the brain used in this investigation are checked and their elimination is discussed. 4. The structure of the duplicitas shows that there exists a mediolateral and probably also a cranio-caudal regulation in grafts of the dorsal blastoporal lip of the early gastrula. 5. In the brain one may distinguish between ‘primary’ structures which are always present, and ‘secondary’ structures which are more variable. Therefore, one may probably divide the causal analysis of the development of the central nervous system into the determination of the ‘ground plan’ of the primary structures and the more dependent development of the ‘secondary’ ones (specific formations). 6. The brains of the secondary embryonic rudiments of these duplicitas are formed in all cases up to a certain level; caudally to this level the brain-parts are normally proportioned, but the most anterior part may be reduced in size. This material can be arranged into a complete regression series, beginning with the reduction of the telencephalon and ending with a completely acephalic embryo. From this development one may conclude that the determination of the central nervous system occurs in a large number of successive zones, which are qualitatively ‘equivalent’, and which are determined by (qualitatively or quantitatively) different values of the organizing ‘agent’. 7. There are indications that the infundibulum and hypophysis are determined by a triple contact between presumptive neural plate, prechordal plate and cephalic ectoderm after the appearance of the neural plate. 8. After special staining these incomplete nervous systems may form a very important source of data for the causal analysis of the development of tracts and nuclei in the central nervous system. 9. With the conclusions drawn from these experiments and the data given in the extensive literature on this subject, a new working hypothesis on the determination of the central nervous system is put forward. This theory involves the assumption (among others) of an equilibrium reaction between a strong mesodermal and a weak ectodermal gradient. The character of the determination process probably changes from being at first purely quantitative to become qualitative with increasing age. 10. Finally, the regional determination of the secondary rudiment in duplicitas is probably determined by a triple interaction between the induction field of the graft, the primary regional structure of the ectoderm and the regional influences of the primary rudiment.


2010 ◽  
Vol 24 (4) ◽  
pp. 249-252 ◽  
Author(s):  
Márk Molnár ◽  
Roland Boha ◽  
Balázs Czigler ◽  
Zsófia Anna Gaál

This review surveys relevant and recent data of the pertinent literature regarding the acute effect of alcohol on various kinds of memory processes with special emphasis on working memory. The characteristics of different types of long-term memory (LTM) and short-term memory (STM) processes are summarized with an attempt to relate these to various structures in the brain. LTM is typically impaired by chronic alcohol intake but according to some data a single dose of ethanol may have long lasting effects if administered at a critically important age. The most commonly seen deleterious acute effect of alcohol to STM appears following large doses of ethanol in conditions of “binge drinking” causing the “blackout” phenomenon. However, with the application of various techniques and well-structured behavioral paradigms it is possible to detect, albeit occasionally, subtle changes of cognitive processes even as a result of a low dose of alcohol. These data may be important for the consideration of legal consequences of low-dose ethanol intake in conditions such as driving, etc.


Author(s):  
Peter R. Breggin

BACKGROUND: The vaccine/autism controversy has caused vast scientific and public confusion, and it has set back research and education into genuine vaccine-induced neurological disorders. The great strawman of autism has been so emphasized by the vaccine industry that it, and it alone, often appears in authoritative discussions of adverse effects of the MMR and other vaccines. By dismissing the chimerical vaccine/autism controversy, vaccine defenders often dismiss all genuinely neurological aftereffects of the MMR (measles, mumps, and rubella) and other vaccines, including well-documented events, such as relatively rare cases of encephalopathy and encephalitis. OBJECTIVE: This report explains that autism is not a physical or neurological disorder. It is not caused by injury or disease of the brain. It is a developmental disorder that has no physical origins and no physical symptoms. It is extremely unlikely that vaccines are causing autism; but it is extremely likely that they are causing more neurological damage than currently appreciated, some of it resulting in psychosocial disabilities that can be confused with autism and other psychosocial disorders. This confusion between a developmental, psychosocial disorder and a physical neurological disease has played into the hands of interest groups who want to deny that vaccines have any neurological and associated neuropsychiatric effects. METHODS: A review of the scientific literature, textbooks, and related media commentary is integrated with basic clinical knowledge. RESULTS: This report shows how scientific sources have used the vaccine/autism controversy to avoid dealing with genuine neurological risks associated with vaccines and summarizes evidence that vaccines, including the MMR, can cause serious neurological disorders. Manufacturers have been allowed by the US Food and Drug Administration (FDA) to gain vaccine approval without placebo-controlled clinical trials. CONCLUSIONS: The misleading vaccine autism controversy must be set aside in favor of examining actual neurological harms associated with vaccines, including building on existing research that has been ignored. Manufacturers of vaccines must be required to conduct placebo-controlled clinical studies for existing vaccines and for government approval of new vaccines. Many probable or confirmed neurological adverse events occur within a few days or weeks after immunization and could be detected if the trials were sufficiently large. Contrary to current opinion, large, long-term placebo-controlled trials of existing and new vaccines would be relatively easy and safe to conduct.


2004 ◽  
pp. 406-412
Author(s):  
Paul Okunieff ◽  
Michael C. Schell ◽  
Russell Ruo ◽  
E. Ronald Hale ◽  
Walter G. O'Dell ◽  
...  

✓ The role of radiosurgery in the treatment of patients with advanced-stage metastatic disease is currently under debate. Previous randomized studies have not consistently supported the use of radiosurgery to treat patients with numbers of brain metastases. In negative-results studies, however, intracranial tumor control was high but extracranial disease progressed; thus, patient survival was not greatly affected, although neurocognitive function was generally maintained until death. Because the future promises improved systemic (extracranial) therapy, the successful control of brain disease is that much more crucial. Thus, for selected patients with multiple metastases to the brain who remain in good neurological condition, aggressive lesion-targeting radiosurgery should be very useful. Although a major limitation to success of this therapy is the lack of control of extracranial disease in most patients, it is clear that well-designed, aggressive treatment substantially decreases the progression of brain metastases and also improves neurocognitive survival. The authors present the management and a methodology for rational treatment of a patient with breast cancer who has harbored 24 brain metastases during a 3-year period.


Author(s):  
Amteshwar Singh Jaggi

Aim: The aim of the present study is to explore the neuroprotective effects of remote ischemic preconditioning in long term cognitive impairment after global cerebral ischemia induced-vascular dementia in mice. Material and methods: The mice were subjected to global cerebral ischemia by occluding the bilateral common carotid arteries for 12 minutes followed by the 24 hours of the reperfusion. The remote ischemic preconditioning stimulus was delivered in the form of 4 cycles of ischemia/reperfusion for 5 minutes each. The cerebral ischemic injury induced-long term cognitive impairment-related learning and memory alterations was assessed using morris water maze, the motor performances of the animals were evaluated using rota-rod test and neurological severity score. The cerebral infract size of the brain were quantified using triphenyltetrazolium chloride staining. Results: Global cerebral ischemia causes long term memory impairment, decreases motor performances and increases the brain infract size in animals. The delivery of remote ischemic preconditioning stimulus significantly abolished the long-term cognitive impairment and ameliorates the motor performances as well as cerebral infract size in brain. Conclusion: The remote ischemic preconditioning mediates neuro protection against global cerebral ischemic injury induced long-term cognitive impairment.


2017 ◽  
Vol 14 (4) ◽  
pp. 441-452 ◽  
Author(s):  
Sofia Wenzler ◽  
Christian Knochel ◽  
Ceylan Balaban ◽  
Dominik Kraft ◽  
Juliane Kopf ◽  
...  

Depression is a common neuropsychiatric manifestation among Alzheimer’s disease (AD) patients. It may compromise everyday activities and lead to a faster cognitive decline as well as worse quality of life. The identification of promising biomarkers may therefore help to timely initiate and improve the treatment of preclinical and clinical states of AD, and to improve the long-term functional outcome. In this narrative review, we report studies that investigated biomarkers for AD-related depression. Genetic findings state AD-related depression as a rather complex, multifactorial trait with relevant environmental and inherited contributors. However, one specific set of genes, the brain derived neurotrophic factor (BDNF), specifically the Val66Met polymorphism, may play a crucial role in AD-related depression. Regarding neuroimaging markers, the most promising findings reveal structural impairments in the cortico-subcortical networks that are related to affect regulation and reward / aversion control. Functional imaging studies reveal abnormalities in predominantly frontal and temporal regions. Furthermore, CSF based biomarkers are seen as potentially promising for the diagnostic process showing abnormalities in metabolic pathways that contribute to AD-related depression. However, there is a need for standardization of methodological issues and for replication of current evidence with larger cohorts and prospective studies.


Sign in / Sign up

Export Citation Format

Share Document