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Journal ArticleDOI

Three-dimensional reconstruction of the embryonic pancreas in the grass snake Natrix natrix L. (Lepidosauria, Serpentes) based on histological studies

01 Apr 2017-Zoology (Zoology (Jena))-Vol. 121, pp 91-110
TL;DR: The histological and 3D reconstructions suggest that the untypical topography of the organ systems in snakes may determine the unique development of the pancreas in these animals.
About: This article is published in Zoology.The article was published on 2017-04-01. It has received 12 citations till now. The article focuses on the topics: Natrix & Grass snake.
Citations
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Journal ArticleDOI
TL;DR: Dealing with sebaceous carcinoma is important prognostically but sometimes challenging with routine histopathology, androgen receptor (AR) was found to be confirmatory in only 36% of cases and not dependent on the size of the tumor available.
Abstract: 1757 Identification of Ocular Sebaceous Neoplasia with Evaluation for Mismatch Repair Proteins L Schoenfield, J Anthony, R Djohan, I Lalak, M Levine, P Ng, J Perry, A Singh, T Plesec. Cleveland Clinic, Cleveland, OH. Background: Recognizing sebaceous carcinoma is important because of its risk for metastasis and tumor death. Histopathology alone is often difficult because fresh tissue for oil red-O stain is not always available. Several immunohistochemical stains (IHC) have been evaluated but often the diagnosis is elusive. Furthermore, the diagnosis of a sebaceous adenoma or carcinoma raises the possibility of Lynch syndrome, a cancer predisposition syndrome. Mismatch repair protein(MMR) abnormalities are a feature of Lynch syndrome, and they can be detected with IHC for the MLH1, MSH2, PMS2, and MSH6 proteins. Design: 14 sebaceous carcinomas and 3 adenomas from the eyelid (17 specimens) from 14 patients were evaluated for oil red-O when possible as well as IHC for AR, EMA, BER-EP4, CAM5.2 for diagnosis. MMR for MLH1, MSH2, PMS2, and MSH6 by IHC were evaluated as a possible screening panel for Lynch syndrome. Two patients already had other tissue tested by PCR for microsatellite instability (MSI) for Lynch syndrome. Results: Oil red-O was done on 6 of 17 specimens and positive in 5 of the 6 (83%). AR was positive in 2 of 3 adenomas (67%) and 5 of 14 carcinomas (36%). EMA was positive in 2 of 3 adenomas (67%) and 11 of 14 carcinomas (79%). BER-EP4 was negative in all 3 adenomas and positive in 7 of 14 carcinomas (50%). CAM5.2 was positive in 1 of 3 adenomas (33%) and 8 of 14 carcinomas (57%). All 17 specimens(100%) showed positive nuclear staining for MLH1 and PMS2, indicative of normal protein expression. In 14 of 17 specimens from 12 patients, MSH2 and MSH6 were also normal. 3 specimens from 2 patients that had rare positive cells for MSH2 and MSH6. Both patients had previous colonic tumors tested for MSI and were found to be MSI-H, indicative of possible Lynch syndrome. Conclusions: Diagnosing sebaceous carcinoma is important prognostically but sometimes challenging with routine histopathology. In our experience androgen receptor (AR) was found to be confirmatory in only 36% of cases and not dependent on the size of the tumor available. The other IHC stains were of marginal benefit and not specific. While none of the cases showed complete loss of expression of a MMR protein, there were 2 patients in with only rare positive cells who had known MSI-H tumors in the colon, suggestive of Lynch syndrome. Additional studies of these eyelid tumors may elucidate the possible role of using them for screening for Lynch syndrome.

468 citations

Journal ArticleDOI
TL;DR: The main ophidian taxa (Scolecophidia, Henophidia and Caenophidia), just like other squamate clades, seem to be evolutionarily conservative at some levels with respect to the VNO and associated structures morphology.
Abstract: Snakes are considered to be vomerolfaction specialists. They are members of one of the most diverse groups of vertebrates, Squamata. The vomeronasal organ and the associated structures (such as the lacrimal duct, choanal groove, lamina transversalis anterior and cupola Jacobsoni) of adult lizards and snakes have received much anatomical, histological, physiological and behavioural attention. However, only limited embryological investigation into these structures, constrained to some anatomical or cellular studies and brief surveys, has been carried out thus far. The purpose of this study was, first, to examine the embryonic development of the vomeronasal organ and the associated structures in the grass snake (Natrix natrix), using three-dimensional reconstructions based on histological studies, and, second, to compare the obtained results with those presented in known publications on other snakes and lizards. Five major developmental processes were taken into consideration in this study: separation of the vomeronasal organ from the nasal cavity and its specialization, development of the mushroom body, formation of the lacrimal duct, development of the cupola Jacobsoni and its relation to the vomeronasal nerve, and specialization of the sensory epithelium. Our visualizations showed the VNO in relation to the nasal cavity, choanal groove, lacrimal duct and cupola Jacobsoni at different embryonic stages. We confirmed that the choanal groove disappears gradually, which indicates that this structure is absent in adult grass snakes. On our histological sections, we observed a gradual growth in the height of the columns of the vomeronasal sensory epithelium and widening of the spaces between them. The main ophidian taxa (Scolecophidia, Henophidia and Caenophidia), just like other squamate clades, seem to be evolutionarily conservative at some levels with respect to the VNO and associated structures morphology. Thus, it was possible to homologize certain embryonic levels of the anatomical and histological complexity, observed in the grass snake, with adult conditions of certain groups of Squamata. This may reflect evolutionary shift in Squamata from visually oriented predators to vomerolfaction specialists. Our descriptions offer material useful for future comparative studies of Squamata, both at their anatomical and histological levels.

25 citations


Cites background from "Three-dimensional reconstruction of..."

  • ...It is worth mentioning that experimental data, such as histological images, provide only partial static information about the organogenesis of any organ [58]....

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Journal ArticleDOI
TL;DR: The embryological data confirmed recent findings about the nature of some developmental processes in squamates, for example, involvement of the lateral nasal prominence in the formation of the choanal groove and allows for redefinition of the anterior concha of Sphenodon.
Abstract: The vomeronasal organ (VNO), nasal cavity, lacrimal duct, choanal groove, and associated parts of the superficial (soft tissue) palate are called the naso-palatal complex. Despite the morphological diversity of the squamate noses, little is known about the embryological basis of this variation. Moreover, developmental data might be especially interesting in light of the morpho-molecular discordance of squamate phylogeny, since a 'molecular scenario' implies an occurrence of unexpected scale of homoplasy also in olfactory systems. In this study, we used X-ray microtomography and light microscopy to describe morphogenesis of the naso-palatal complex in two gekkotans: Lepidodactylus lugubris (Gekkonidae) and Eublepharis macularius (Eublepharidae). Our embryological data confirmed recent findings about the nature of some developmental processes in squamates, for example, involvement of the lateral nasal prominence in the formation of the choanal groove. Moreover, our study revealed previously unknown differences between the studied gekkotans and allows us to propose redefinition of the anterior concha of Sphenodon. Interpretation of some described conditions might be problematic in the phylogenetic context, since they represent unknown: squamate, nonophidian squamate, or gekkotan features.

7 citations


Cites methods from "Three-dimensional reconstruction of..."

  • ...In this case, the eggs were half-buried in vermiculite mixed with water at a 1:1 ratio by weight (Rupik, 2012; Swadźba & Rupik, 2012; Rupik et al., 2016; Kowalska et al., 2017)....

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Journal ArticleDOI
TL;DR: Egg tooth ontogeny in two gekkotan species, the leopard gecko Eublepharis macularius and the mourning gecko Lepidodactylus lugubris, was compared using microtomography, scanning electron microscopy, and light microscopy to reveal differences in egg tooth implantation between Gekkota and Unidentata.
Abstract: The egg tooth of squamates evolved to facilitate hatching from mineralized eggshells Squamate reptiles can assist their hatching with a single unpaired egg tooth (unidentates) or double egg teeth (geckos and dibamids) Egg tooth ontogeny in two gekkotan species, the leopard gecko Eublepharis macularius and the mourning gecko Lepidodactylus lugubris, was compared using microtomography, scanning electron microscopy, and light microscopy Investigated species are characterized by different hardnesses of their eggshells Leopard geckos eggs have a relatively soft and flexible parchment (leathery) shell, while eggshells of mourning geckos are hard and rigid Embryos of both species, like other Gekkota, have double egg teeth, but the morphology of these structures differs between the investigated species These differences in shape, localization, and spatial orientation were present from the earliest stages of embryonic development In mourning gecko, anlagen of differentiating egg teeth change their position on the palate during embryonic development Initially they are separated by condensed mesenchyme, but later in development, their enamel organs are connected In leopard geckos, the localization of egg tooth germs does not change, but their spatial orientation does Egg teeth of this species shift from inward to outward orientation This is likely related to differences in structure and mechanical properties of eggshells in the studied species In investigated species, two hatching mechanisms are possible during emergence of young individuals We speculate that mourning geckos break the eggshell through puncturing action with egg teeth, similar to the pipping phase of chick and turtles embryos Egg teeth of leopard geckos cut egg membranes similarly to most squamates Our results also revealed differences in egg tooth implantation between Gekkota and Unidentata: gekkotan egg teeth are subthecodont (in shallow sockets), while those in unidentates are acrodont (attached to the top of the alveolar ridge) © 2020 Wiley Periodicals LLC

6 citations

References
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Journal ArticleDOI
19 Oct 2001-Science
TL;DR: A role for blood vessels as a source of developmental signals during pancreatic organogenesis is demonstrated and results indicate that vessels not only provide metabolic sustenance, but also provide inductive signals for organ development.
Abstract: Blood vessels supply developing organs with metabolic sustenance. Here, we demonstrate a role for blood vessels as a source of developmental signals during pancreatic organogenesis. In vitro experiments with embryonic mouse tissues demonstrate that blood vessel endothelium induces insulin expression in isolated endoderm. Removal of the dorsal aorta in Xenopus laevis embryos results in the failure of insulin expression in vivo. Furthermore, using transgenic mice, we show that ectopic vascularization in the posterior foregut leads to ectopic insulin expression and islet hyperplasia. These results indicate that vessels not only provide metabolic sustenance, but also provide inductive signals for organ development.

1,048 citations

Journal ArticleDOI
TL;DR: Observational studies suggest strongly that both endocrine and exocrine cells arise from the same endodermal rudiment, and it seems likely that there is a continuous slow turnover of cells, fed from a stem cells population in the ducts, and that the controls on the production rate are local rather than systemic.
Abstract: The pancreas is an organ containing two distinct populations of cells, the exocrine cells that secrete enzymes into the digestive tract, and the endocrine cells that secrete hormones into the bloodstream. It arises from the endoderm as a dorsal and a ventral bud which fuse together to form the single organ. Mammals, birds, reptiles and amphibians have a pancreas with similar histology and mode of development, while in some fish, the islet cells are segregated as Brockmann bodies. Invertebrates do not have a pancreas, but comparable endocrine cells may be found in the gut or the brain. The early pancreatic bud shows uniform expression of the homeobox gene IPF-1 (also known as IDX-1, STF-1 or PDX), which when mutated to inactivity leads to total absence of the organ. The occurrence of heterotopic pancreas in the embryo, and also the metaplasias that can be displayed by a regenerating pancreas in the adult, both suggest that only a few gene products distinguish the pancreatic cell state from that of the surrounding tissues of duodenum, gall bladder and liver. In the developing pancreatic buds, the endocrine cells start to differentiate before the exocrine cells, and co-expression of different hormones by the same cell is often observed at early stages. Although pancreatic endocrine cells produce many gene products also characteristic of neurons, evidence from in vitro cultures and from quailchick grafts shows that they are of endogenous and not of neural crest origin. Observational studies suggest strongly that both endocrine and exocrine cells arise from the same endodermal rudiment. Development of the pancreas in embryonic life requires a trophic stimulus from the associated mesenchyme. In postnatal life, all cell types in the pancreas continue to grow. Destruction of acinar tissue by duct ligation or ethionine treatment is followed by rapid regeneration. Surgical removal of parts of the pancreas is followed by moderate but incomplete regeneration of both acini and islets. Poisoning with alloxan or streptozotocin can lead to permanent depletion of beta cells. Although the cell kinetics of the pancreas are not understood, it seems likely that there is a continuous slow turnover of cells, fed from a stem cells population in the ducts, and that the controls on the production rate of each cell type are local rather than systemic.

1,007 citations

Book
01 Jan 1996
TL;DR: Adding Reptile Patients to Your Practice and Specific Diseases and Conditions: Acariasis, Anorexia, Postural Abnormalities, Seizures, Convulsions, Tremors.
Abstract: Section 1. Introduction: Adding Reptile Patients to Your Practice. General Husbandry and Management. Reptile Zoonoses and Threats to Public Health. Reference Sources for Reptile Clinicians. Section 2. Biology: Snakes. Lizards. Turtles. Crocodilians. Section 3. Special Topics: Cardiology and Circulations. Dermatology. Microbiology. Neoplasia. Neurology. Nutrition. Ophthalmology. Parasitology. Perinatology of Pet Reptiles. Reproductive Biology. Viral Diseases. Section 4. Special Techniques and Procedures. Allometric Scaling: Extrapolating Treatment Regimens for Reptiles. Anesthesia. Clinical Pathology. Diagnostic Imaging. Diagnostic Techniques. Euthanasia and Necropsy. Fracture Management. Soft Tissue Surgery. Therapeutics. Section 5. Differential Diagnosis By Symptoms: Snakes. Lizards. Turtles. Crocodilians. Section 6. Specific Diseases and Conditions: Acariasis. Anorexia. Aural Abscesses. Bites from Prey. Cloacal Prolapse. Cryptosporidiosis. Diaorrhea. Digit Abnormalities. Dysecdysis. Dystocias. Gout. Hemoparasites. Hypo- And Hypervitaminosis A. Metabolic Bone Disease. Ophidean Paramyxovirus (OPMV). Paraphimosis. Pneumonia and Normal Respiratory Function. Postural Abnormalities. Seizures, Convulsions, Tremors. Shell Damage. Tail Damage. Thermal Burns. Upper Alimentary Tract Disease. Vomiting and Regurgitation. Section 7. Appendix: Sea Turtle Rehabilitation. Amphibian Husbandry and Medicine. Management of Large Reptile Collections. Evaluation of Artificial Lighting. Reptile and Amphibian Formulary. Hematologic and Blood Chemistry Values in Reptiles. Radiographic Anatomy.

830 citations

Journal ArticleDOI
TL;DR: This work discusses how developmental mechanisms that regulate endoderm organogenesis are used to direct differentiation of embryonic stem cells into specific adult cell types, which function to alleviate disease symptoms in animal models.
Abstract: The endoderm germ layer contributes to the respiratory and gastrointestinal tracts and to all of their associated organs. Over the past decade, studies in vertebrate model organisms, including frog, fish, chick, and mouse, have greatly enhanced our understanding of the molecular basis of endoderm organ development. We review this progress with a focus on early stages of endoderm organogenesis including endoderm formation, gut tube morphogenesis and patterning, and organ specification. Lastly, we discuss how developmental mechanisms that regulate endoderm organogenesis are used to direct differentiation of embryonic stem cells into specific adult cell types, which function to alleviate disease symptoms in animal models.

706 citations


"Three-dimensional reconstruction of..." refers background in this paper

  • ...According to the first model he ventral pancreatic buds can be formed directly from the venral wall of the gut as one or two anlagen (Holtfreter, 1925; Deutsch t al., 2001; Tremblay and Zaret, 2005; Murtaugh, 2007; Franklin t al., 2008; Zorn and Wells, 2009)....

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Journal ArticleDOI
Gail Deutsch1, Joonil Jung1, Minghua Zheng1, José M. Lora1, Kenneth S. Zaret1 
TL;DR: It is found that the liver and ventral pancreas are specified at the same time and in the same general domain of cells.
Abstract: The pancreas emerges independently from dorsal and ventral domains of embryonic gut endoderm. Gene inactivation experiments in mice have identified factors required for dorsal pancreas development, but factors that initiate the ventral pancreas have remained elusive. In this study, we investigated the hypothesis that the emergence of the ventral pancreas is related to the emergence of the liver. We find that the liver and ventral pancreas are specified at the same time and in the same general domain of cells. Using embryo tissue explantation experiments, we find that the default fate of the ventral foregut endoderm is to activate the pancreas gene program. FGF signalling from the cardiac mesoderm diverts this endoderm to express genes for liver instead of those for pancreas. No evidence was found to indicate that the cell type choice for pancreas or liver involves a selection for growth or viability. Cardiac mesoderm or FGF induces the local expression of sonic hedgehog, which in turn is inhibitory to pancreas but not to liver. The bipotential precursor cell population for pancreas and liver in embryonic development and its fate selection by FGF has features that appear to be recapitulated in the adult pancreas and are reflected in the evolution of these organs.

611 citations


"Three-dimensional reconstruction of..." refers background in this paper

  • ...The hepatic bud and the ventral buds of the ancreas develop from the ventral diverticula (Tribe, 1918; Slack, 995; Deutsch et al., 2001)....

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  • ...The literature review also indicates that there is a controversy bout whether the ventral pancreatic primordia derive directly rom the gut wall (first model) or rather from the hepatic diverticuum (second model) which is formed from the gut (Choronshitzky, 900; Tribe, 1918; Deutsch et al., 2001)....

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