Expression of the N-myc proto-oncogene during the early development of Xenopus laevis

Development ◽  
1990 ◽  
Vol 110 (3) ◽  
pp. 885-896
Author(s):  
P.D. Vize ◽  
A. Vaughan ◽  
P. Krieg

The N-myc proto-oncogene is expressed in a wide range of tissues during mammalian embryogenesis. This observation, along with the oncogenic capacity of this gene, has led to the suggestion that N-myc plays an important role in early development. However, due to the complexity of the expression pattern and the difficulty of manipulating mammalian embryos, little progress has been made towards understanding the developmental function of this gene. To enable a more detailed analysis of the role of this gene in early development, a study of the Xenopus homologue of N-myc was undertaken. Xenopus N-myc cDNA clones were isolated from a neurula library using a murine N-myc probe. Analysis of the timing of expression of N-myc mRNA and of the distribution of N-myc protein during Xenopus development indicate that this gene may be playing an important role in the formation of a number of embryonic structures, including the nervous system. N-myc is initially expressed as a maternal RNA, but this mRNA is degraded by the gastrula stage of development. Zygotic expression does not commence until late neurula. Examination of the distribution of the N-myc protein by whole-mount immunohistochemistry indicates that the early embryonic expression occurs in the central nervous system, the neural crest, the somites and the epidermis. Later expression is mostly within the head and somites. Specific structures within the head that express the protein include the eye, otic vesicle, fore and hindbrain and a number of cranial nerves. The results demonstrate that while N-myc is expressed in the developing nervous system of Xenopus, the timing of expression indicates that it is unlikely to be involved in regulation of the very first stages of neurogenesis.

2021 ◽  
Vol 40 (4) ◽  
pp. 33-42
Author(s):  
Igor V. Litvinenko ◽  
Miroslav M. Odinak ◽  
Nikolay V. Tsygan ◽  
Aleksander V. Ryabtsev

The central nervous system seems to be quite vulnerable to SARS-CoV-2, leading to a variety of alteration pathways, high incidence and variability of the neurological symptoms of COVID-19. The COVID-19 symptoms, possibly associated with alteration to the central nervous system, include hyperthermia, shortness of breath, fatigue, headache, dizziness, dysphonia, dysphagia, hyposmia and anosmia, hypogeusia and ageusia, impairment of consciousness. The impairment of olfaction and gustation are the most common symptoms of the nervous system alteration (98% and 70%, respectively), which is most likely a consequence of the alteration of the receptors. Presumably the pathogenesis of dysphonia and dysphagia may involve neurodegenerative mechanisms or may be associated with a predominantly demyelinating alteration of the caudal cranial nerves. Pathomorphological findings in the brain of the COVID-19 patients include diffuse hypoxic and focal ischemic injuries of various sizes up to ischemic infarctions (in thrombosis of large arteries); microangiopathy; vasculitis; diapedetic and confluent hemorrhages with possible progression to hemorrhagic infarctions and rarely intracerebral hematomas. Acute cerebrovascular accident worsens the course of COVID-19 and can worsen the clinical outcome, taking into account the mechanisms of the central nervous system alteration in highly contagious coronavirus infections (SARS-CoV, MERS, SARS-CoV-2), including embolism, hypoxia, neurodegeneration, systemic inflammatory response and immune-mediated alteartion to the nervous tissue. A fairly rare complication of coronavirus infection, however, acute myelitis requires attention due to the severity of neurological disorders. The literature data show high incidence and polymorphism of the symptoms of the central nervous system alteration, as well as the important role of the cerebrovascular and neurodegenerative pathogenesis of brain alteration in COVID-19, which is taken into account in examining and treating the patients with new coronavirus infection. (1 figure, bibliography: 61 refs)


2021 ◽  
Vol 22 (14) ◽  
pp. 7294
Author(s):  
Shadi Mahjoum ◽  
David Rufino-Ramos ◽  
Luís Pereira de Almeida ◽  
Marike L. D. Broekman ◽  
Xandra O. Breakefield ◽  
...  

The central nervous system (CNS) consists of a heterogeneous population of cells with highly specialized functions. For optimal functioning of the CNS, in disease and in health, intricate communication between these cells is vital. One important mechanism of cellular communication is the release and uptake of extracellular vesicles (EVs). EVs are membrane enclosed particles actively released by cells, containing a wide array of proteins, lipids, RNA, and DNA. These EVs can be taken up by neighboring or distant cells, and influence a wide range of processes. Due to the complexity and relative inaccessibility of the CNS, our current understanding of the role of EVs is mainly derived in vitro work. However, recently new methods and techniques have opened the ability to study the role of EVs in the CNS in vivo. In this review, we discuss the current developments in our understanding of the role of EVs in the CNS in vivo.


2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Mohammad Javad Nasr ◽  
Ali Alizadeh Khatir ◽  
Arefeh Babazadeh ◽  
Soheil Ebrahimpour

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus that causes coronavirus disease 2019 (COVID-19). The latest data show that more than 211.7 million people were infected and more than 4.4 million deaths have been reported. The illness presents a wide range of symptoms, ranging from mild to severe. Mild symptoms include cough, fever, dyspnea, fatigue, myalgia and arthralgia, anosmia, and dysgeusia. Furthermore, this virus can affect the central nervous system (CNS) and present a range of mild to severe nervous symptoms, from headache and dysphoria to loss of consciousness, coma, paralysis, and acute cerebrovascular disease. The virus can enter nonneuronal cells of the olfactory epithelium and cause a complete loss of smell. Anosmia and hyposmia are commonly reported in clinics, and being asymptomatic or showing mild symptoms can be primary symptoms in early infected persons. Dysgeusia/hypogeusia is another symptom presented with anosmia/hyposmia. In this article, we reviewed the articles of anosmia and suggested a possible mechanism for this.


2020 ◽  
pp. 49-56
Author(s):  
T. Shirshova

Disorders of the musculoskeletal system in school-age children occupy 1-2 places in the structure of functional abnormalities. Cognitive impairment without organic damage to the central nervous system is detected in 30-56% of healthy school children. Along with the increase in the incidence rate, the demand for rehabilitation systems, which allow patients to return to normal life as soon as possible and maintain the motivation for the rehabilitation process, is also growing. Adaptation of rehabilitation techniques, ease of equipment management, availability of specially trained personnel and availability of technical support for complexes becomes important.


2019 ◽  
Vol 20 (7) ◽  
pp. 750-758 ◽  
Author(s):  
Yi Wu ◽  
Hengxun He ◽  
Zhibin Cheng ◽  
Yueyu Bai ◽  
Xi Ma

Obesity is one of the main challenges of public health in the 21st century. Obesity can induce a series of chronic metabolic diseases, such as diabetes, dyslipidemia, hypertension and nonalcoholic fatty liver, which seriously affect human health. Gut-brain axis, the two-direction pathway formed between enteric nervous system and central nervous system, plays a vital role in the occurrence and development of obesity. Gastrointestinal signals are projected through the gut-brain axis to nervous system, and respond to various gastrointestinal stimulation. The central nervous system regulates visceral activity through the gut-brain axis. Brain-gut peptides have important regulatory roles in the gut-brain axis. The brain-gut peptides of the gastrointestinal system and the nervous system regulate the gastrointestinal movement, feeling, secretion, absorption and other complex functions through endocrine, neurosecretion and paracrine to secrete peptides. Both neuropeptide Y and peptide YY belong to the pancreatic polypeptide family and are important brain-gut peptides. Neuropeptide Y and peptide YY have functions that are closely related to appetite regulation and obesity formation. This review describes the role of the gutbrain axis in regulating appetite and maintaining energy balance, and the functions of brain-gut peptides neuropeptide Y and peptide YY in obesity. The relationship between NPY and PYY and the interaction between the NPY-PYY signaling with the gut microbiota are also described in this review.


2018 ◽  
Vol 17 (4) ◽  
pp. 272-279 ◽  
Author(s):  
Yudan Zhu ◽  
Shuzhang Zhang ◽  
Yijun Feng ◽  
Qian Xiao ◽  
Jiwei Cheng ◽  
...  

Background & Objective: The large conductance calcium-activated potassium (BK) channel, extensively distributed in the central nervous system (CNS), is considered as a vital player in the pathogenesis of epilepsy, with evidence implicating derangement of K+ as well as regulating action potential shape and duration. However, unlike other channels implicated in epilepsy whose function in neurons could clearly be labeled “excitatory” or “inhibitory”, the unique physiological behavior of the BK channel allows it to both augment and decrease the excitability of neurons. Thus, the role of BK in epilepsy is controversial so far, and a growing area of intense investigation. Conclusion: Here, this review aims to highlight recent discoveries on the dichotomous role of BK channels in epilepsy, focusing on relevant BK-dependent pro- as well as antiepileptic pathways, and discuss the potential of BK specific modulators for the treatment of epilepsy.


2020 ◽  
Vol 21 (15) ◽  
pp. 5475 ◽  
Author(s):  
Manuela Pennisi ◽  
Giuseppe Lanza ◽  
Luca Falzone ◽  
Francesco Fisicaro ◽  
Raffaele Ferri ◽  
...  

Increasing evidence suggests that Severe Acute Respiratory Syndrome-coronavirus-2 (SARS-CoV-2) can also invade the central nervous system (CNS). However, findings available on its neurological manifestations and their pathogenic mechanisms have not yet been systematically addressed. A literature search on neurological complications reported in patients with COVID-19 until June 2020 produced a total of 23 studies. Overall, these papers report that patients may exhibit a wide range of neurological manifestations, including encephalopathy, encephalitis, seizures, cerebrovascular events, acute polyneuropathy, headache, hypogeusia, and hyposmia, as well as some non-specific symptoms. Whether these features can be an indirect and unspecific consequence of the pulmonary disease or a generalized inflammatory state on the CNS remains to be determined; also, they may rather reflect direct SARS-CoV-2-related neuronal damage. Hematogenous versus transsynaptic propagation, the role of the angiotensin II converting enzyme receptor-2, the spread across the blood-brain barrier, the impact of the hyperimmune response (the so-called “cytokine storm”), and the possibility of virus persistence within some CNS resident cells are still debated. The different levels and severity of neurotropism and neurovirulence in patients with COVID-19 might be explained by a combination of viral and host factors and by their interaction.


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