pigment cells
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2022 ◽  
Author(s):  
Hui Lu ◽  
Doudou Chen ◽  
Siquan Zhu

Abstract Purposes: This study was aimed to evaluate the clinical manifestations of recurrent uveitis in patients underwent pupil coroplasty combined with cataract surgery, and discovery the histopathological changes of iris tissues. Methods: There 28 patients with recurrent uveitis-induced cataract, who had underwent pupil coroplasty, phacoemulsification, and intraocular lens implantation were enrolled in this study. The clinical manifestations and outcomes of the enrolled patients were analyzed. The histopathological changes of iris tissues were observed by hematoxylin and eosin (HE) staining. Results: The uveitis were idiopathic in 89.29% cases (n = 25). Before the surgery, 20 cases had no topical medication for at least 3 months. The preoperative BCVA was > 0.5 in all cases. During the follow-up of 5-10 years, no recurrence of uveitis was found in 96.43% cases (n = 27). Uveitis only recurred in one case along with the onset of ankylosing spondylitis at the 6th week after the surgery. HE staining showed obvious atrophy of iris stroma in all samples. The hyperplasia of pigment cells was observed in the pigment epithelium (n = 9) and even invaded into stroma (n = 19). The infiltration of inflammatory cells in iris tissues was found in 7 cases, and neovascularization in the surface of the iris was found in 2 cases. Conclusion: Recurrent uveitis was characterized by the atrophy of iris stroma, and some cases also exhibited hyperplasia of pigment cells and infiltration of inflammatory cells. The surgery proposed in this study can effectively prevent the long-term recurrence of uveitis.


Rekayasa ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 407-415
Author(s):  
Riyan Latifahul Hasanah ◽  
Dwiza Riana

The development of abnormal skin pigment cells can cause a skin cancer called melanoma. Melanoma can be cured if diagnosed and treated in its early stages. Various studies using various technologies have been developed to conduct early detection of melanoma. This research was conducted to diagnose melanoma skin cancer with digital image processing techniques on the dermoscopic image of skin cancer. The diagnosis is made by classifying dermoscopic images based on the types of Common Nevus, Atypical Nevus or Melanoma. Pre-processing is done by changing the RGB image to grayscale (grayscaling), smoothing image using median filtering, and image segmentation based on binary images of skin lesions. The value of Contrast, Correlation, Energy and Homogeneity obtained from the texture feature extraction of the GLCM method is used in the next step, which is the classification process with the Multi-SVM algorithm. The proposed research method shows high accuracy results in diagnosing skin cancer


2021 ◽  
Vol 22 (24) ◽  
pp. 13531
Author(s):  
Jonathan H. P. Dawes ◽  
Robert N. Kelsh

The neural crest shows an astonishing multipotency, generating multiple neural derivatives, but also pigment cells, skeletogenic and other cell types. The question of how this process is controlled has been the subject of an ongoing debate for more than 35 years. Based upon new observations of zebrafish pigment cell development, we have recently proposed a novel, dynamic model that we believe goes some way to resolving the controversy. Here, we will firstly summarize the traditional models and the conflicts between them, before outlining our novel model. We will also examine our recent dynamic modelling studies, looking at how these reveal behaviors compatible with the biology proposed. We will then outline some of the implications of our model, looking at how it might modify our views of the processes of fate specification, differentiation, and commitment.


Author(s):  
S Faraj ◽  
E H Kemp ◽  
D J Gawkrodger

Summary Epidermal melanocyte loss in vitiligo, triggered by stresses ranging from trauma to emotional stress, chemical exposure or metabolite imbalance, to the unknown, can stimulate oxidative stress in pigment cells, which secrete damage-associated molecular patterns that then initiate innate immune responses. Antigen presentation to melanocytes leads to stimulation of autoreactive T cell responses, with further targeting of pigment cells. Studies show a pathogenic basis for cellular stress, innate immune responses and adaptive immunity in vitiligo. Improved understanding of the aetiological mechanisms in vitiligo has already resulted in successful use of the Jak inhibitors in vitiligo. In this review we outline the current understanding of the pathological mechanisms in vitiligo, and locate loci to which therapeutic attack might be directed.


BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Jonathan E. Valencia ◽  
Roberto Feuda ◽  
Dan O. Mellott ◽  
Robert D. Burke ◽  
Isabelle S. Peter

Abstract Background The evolutionary history of cell types provides insights into how morphological and functional complexity arose during animal evolution. Photoreceptor cell types are particularly broadly distributed throughout Bilateria; however, their evolutionary relationship is so far unresolved. Previous studies indicate that ciliary photoreceptors are homologous at least within chordates, and here, we present evidence that a related form of this cell type is also present in echinoderm larvae. Results Larvae of the purple sea urchin Strongylocentrotus purpuratus have photoreceptors that are positioned bilaterally in the oral/anterior apical neurogenic ectoderm. Here, we show that these photoreceptors express the transcription factor Rx, which is commonly expressed in ciliary photoreceptors, together with an atypical opsin of the GO family, opsin3.2, which localizes in particular to the cilia on the cell surface of photoreceptors. We show that these ciliary photoreceptors express the neuronal marker synaptotagmin and are located in proximity to pigment cells. Furthermore, we systematically identified additional transcription factors expressed in these larval photoreceptors and found that a majority are orthologous to transcription factors expressed in vertebrate ciliary photoreceptors, including Otx, Six3, Tbx2/3, and Rx. Based on the developmental expression of rx, these photoreceptors derive from the anterior apical neurogenic ectoderm. However, genes typically involved in eye development in bilateria, including pax6, six1/2, eya, and dac, are not expressed in sea urchin larval photoreceptors but are instead co-expressed in the hydropore canal. Conclusions Based on transcription factor expression, location, and developmental origin, we conclude that the sea urchin larval photoreceptors constitute a cell type that is likely homologous to the ciliary photoreceptors present in chordates.


Author(s):  
Gemma Sutton ◽  
Robert N. Kelsh ◽  
Steffen Scholpp

The neural crest (NC) is a multipotent cell population in vertebrate embryos with extraordinary migratory capacity. The NC is crucial for vertebrate development and forms a myriad of cell derivatives throughout the body, including pigment cells, neuronal cells of the peripheral nervous system, cardiomyocytes and skeletogenic cells in craniofacial tissue. NC induction occurs at the end of gastrulation when the multipotent population of NC progenitors emerges in the ectodermal germ layer in the neural plate border region. In the process of NC fate specification, fate-specific markers are expressed in multipotent progenitors, which subsequently adopt a specific fate. Thus, NC cells delaminate from the neural plate border and migrate extensively throughout the embryo until they differentiate into various cell derivatives. Multiple signalling pathways regulate the processes of NC induction and specification. This review explores the ongoing role of the Wnt/β-catenin signalling pathway during NC development, focusing on research undertaken in the Teleost model organism, zebrafish (Danio rerio). We discuss the function of the Wnt/β-catenin signalling pathway in inducing the NC within the neural plate border and the specification of melanocytes from the NC. The current understanding of NC development suggests a continual role of Wnt/β-catenin signalling in activating and maintaining the gene regulatory network during NC induction and pigment cell specification. We relate this to emerging models and hypotheses on NC fate restriction. Finally, we highlight the ongoing challenges facing NC research, current gaps in knowledge, and this field’s potential future directions.


Author(s):  
Shigeru Kondo ◽  
Masakatsu Watanabe ◽  
Seita Miyazawa

Skin patterns are the first example of the existence of Turing patterns in living organisms. Extensive research on zebrafish, a model organism with stripes on its skin, has revealed the principles of pattern formation at the molecular and cellular levels. Surprisingly, although the networks of cell–cell interactions have been observed to satisfy the ‘short-range activation and long-range inhibition’ prerequisites for Turing pattern formation, numerous individual reactions were not envisioned based on the classical reaction–diffusion model. For example, in real skin, it is not an alteration in concentrations of chemicals, but autonomous migration and proliferation of pigment cells that establish patterns, and cell–cell interactions are mediated via direct contact through cell protrusions. Therefore, the classical reaction–diffusion mechanism cannot be used as it is for modelling skin pattern formation. Various studies are underway to adapt mathematical models to the experimental findings on research into skin patterns, and the purpose of this review is to organize and present them. These novel theoretical methods could be applied to autonomous pattern formation phenomena other than skin patterns. This article is part of the theme issue ‘Recent progress and open frontiers in Turing's theory of morphogenesis’.


2021 ◽  
pp. 414-457
Author(s):  
Elena Locci ◽  
Silvia Raymond

One of the most popular types of skin cancer is acral lentiginous melanoma, which usually appears as an irregular, prominent growth on the palms of the hands, feet, or under the nails. In fact, the symptoms of this cancer, which is a prominent colored spot on the skin, slowly begin to appear. In the first stage, malignant cells remain inside the tissue for months or years. The lesion then acts aggressively and appears on the skin as it exits the epidermis. Experts say this type of melanoma can grow rapidly and penetrate deep into the skin. Unlike other skin cancers that occur due to overexposure to the sun, acral melanoma has nothing to do with it. In appearance, these types of cancer spots are more than 6 mm in size and can be brown, blue-gray, black or red. Early in the onset of the disease, the melanoma may have a smooth surface, but over time it becomes thicker and has a dry, uneven surface. Bleeding and sores on the cancerous spot are also possible in some cases. Now that we know that this type of cancer is not caused by the sun's rays, then what is the reason for its occurrence? Experts say our skin has natural pigments. However, melanoma linginosis develops when some malignant pigment cells begin to proliferate in the primary layers of the epidermis. Scientists do not yet know for sure why pigment cells become malignant, but it may be rooted in genetic mutations. When a doctor diagnoses skin cancer in a person, he or she removes the cancerous spots. This process can be more complicated depending on the size of the cancer cells. If the cancer has spread to the lymph nodes, the healing process will take longer. As with other cancers, early detection of skin cancer can speed up the healing process. Therefore, after seeing any spots or colored spots on the palms of your hands, feet or under your nails, see a specialist immediately. Keywords: Cancer; Cells; Tissues; Tumors; Prevention; Prognosis; Diagnosis; Imaging; Screening; Treatment; Management


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Hyo Sik Jang ◽  
Yujie Chen ◽  
Jiaxin Ge ◽  
Alicia N. Wilkening ◽  
Yiran Hou ◽  
...  

Abstract Background Zebrafish pigment cell differentiation provides an attractive model for studying cell fate progression as a neural crest progenitor engenders diverse cell types, including two morphologically distinct pigment cells: black melanophores and reflective iridophores. Nontrivial classical genetic and transcriptomic approaches have revealed essential molecular mechanisms and gene regulatory circuits that drive neural crest-derived cell fate decisions. However, how the epigenetic landscape contributes to pigment cell differentiation, especially in the context of iridophore cell fate, is poorly understood. Results We chart the global changes in the epigenetic landscape, including DNA methylation and chromatin accessibility, during neural crest differentiation into melanophores and iridophores to identify epigenetic determinants shaping cell type-specific gene expression. Motif enrichment in the epigenetically dynamic regions reveals putative transcription factors that might be responsible for driving pigment cell identity. Through this effort, in the relatively uncharacterized iridophores, we validate alx4a as a necessary and sufficient transcription factor for iridophore differentiation and present evidence on alx4a’s potential regulatory role in guanine synthesis pathway. Conclusions Pigment cell fate is marked by substantial DNA demethylation events coupled with dynamic chromatin accessibility to potentiate gene regulation through cis-regulatory control. Here, we provide a multi-omic resource for neural crest differentiation into melanophores and iridophores. This work led to the discovery and validation of iridophore-specific alx4a transcription factor.


QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Nehal Mohamed Zulfakar ◽  
Samah Ibrahim Hassan ◽  
Abdel-moneim Salah Ahmed

Abstract Background Vitiligo is a common, asymptomatic, acquired depigmentation disorder, clinically characterized by milky white sharply demarcated, macules and patches that are scattered symmetrically or asymmetrically over the body causing severe cosmetic distress and social stigma. It can be classified as nonsegmental, segmental, mixed, or unclassified. In vitiligo, melanocytes are targeted by multiple aggressions leading to marked reduction and destruction of pigment cells, including autoimmune process, altered cellular environment, defective melanocytes migration, stress, and genetic factors. Objective To evaluate the serum CXCL10 level in patients with more than one year stability, compare them with healthy controls and compare the serum and tissue level before and after treatment with NB-UVB. Patients and Methods The present prospective controlled study included 20 patients with stable vitiligo (according to the VIDA activity score age of patients ranged from 18 to 54 years old were divided into 10 males and 10 females, and were recruited from the outpatient clinic of dermatology of Ain Shams University Hospital in the period from october 2018 to march 2019, twenty healthy persons were used as controls. All the patients were subjected to a full history taking, general and local clinical examination laboratory tests, and graded via VIDA score as below, digital photography were taken before and after NB-UVB. Results A Total of 20 patients were enrolled in the study, completed the study till the end of follow up of 24 visits during 12 weeks, their ages ranged from 18 to 54years old with a mean of 32.88 ± 10.42 years. Patients were divided into 10 males (50%) and 10 females (50%). Only one patient (5%) had a past medical history of diabetes mellitus and five patients (25%) had similar vitiligo affection in their families. As regard the mean difference of serum CXCL10 in comparison to tissue levels after the treatment there was no statistically significant differences indicating that serum is good indicator for measurement of expression of CXCR3 expression with less invasive procedure and tissue CXCL10 is not necessary to be measured Conclusion Cxcl10 is a useful marker for vitiligo and its severity Serum CXCL10 is equally significant to tissue CXCL10, so serum CXCL10 can replase invasive tissue CXCL10 Some drugs can be directed against CXCL10 or its receptor CXCR3 and may be a useful tool to control vitiligo in the future.


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