scholarly journals Subplacental development in Galea spixii

2018 ◽  
Vol 38 (11) ◽  
pp. 2175-2182
Author(s):  
Ferdinando V.F. Bezerra ◽  
Phelipe O. Favaron ◽  
Andrea M. Mess ◽  
Hélio N. Araújo Júnior ◽  
Gleidson B. Oliveira ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Animal Models ◽  
Guinea Pig ◽  
Giant Cells ◽  
Trophoblast Invasion ◽  
Close Relative ◽  
Healthy Human ◽  
Pregnant Females ◽  
Specialized Area ◽  
Exchange Processes

ABSTRACT: Animal models are essential to understand healthy human placentation. Guinea pig related rodents became on focus for such purposes. In particular, processes of trophoblast invasion are similar. The latter is associated with a specialized area, the subplacenta. Since previous results showed differences between the guinea pig and its close relative Galea spixii, we aimed to study subplacental development with more detail. We investigated 16 pregnant females of 14 to 55 days of gestation by means of histology, morphometrics, immunohistochemistry and electron microscopy. The overlap between the fetomaternal blood systems resulted as intimate, suggesting some exchange processes. Proliferation was revealed by three independent methods, being most active in early and mid-gestation, which was in accordance to former results. Though degeneration of tissues took place, the subplacenta was maintained towards term with access to the fetal vascularization, supporting a hypothesis about the release of substances to the fetal unit in advanced gestation. In contrast to other species, the extraplacental trophoblast showed a shift from syncytial streamers to giant cells during mid-gestation. Views on placentation in caviomorphs were influenced by the guinea pig, but our data supported recent studies that the subplacenta had a much greater placidity. In regard to subplacental grow, degeneration and likely also exchange processes, Galea and other species showed a more basal pattern of caviomorphs than the guinea pig. Such differences should be considered, when choosing most adequate animal models for special purposes in comparison to human placentation.

scholarly journals Is There a Brain Microbiome?

2021 ◽  
Vol 16 ◽  
pp. 263310552110187
Author(s):  
Christopher D Link
Keyword(s):  
Animal Models ◽  
Human Brain ◽  
Neurodegenerative Diseases ◽  
Ground Truth ◽  
Healthy Human ◽  
Strong Motivation ◽  
The Many ◽  
The Brain

Numerous studies have identified microbial sequences or epitopes in pathological and non-pathological human brain samples. It has not been resolved if these observations are artifactual, or truly represent population of the brain by microbes. Given the tempting speculation that resident microbes could play a role in the many neuropsychiatric and neurodegenerative diseases that currently lack clear etiologies, there is a strong motivation to determine the “ground truth” of microbial existence in living brains. Here I argue that the evidence for the presence of microbes in diseased brains is quite strong, but a compelling demonstration of resident microbes in the healthy human brain remains to be done. Dedicated animal models studies may be required to determine if there is indeed a “brain microbiome.”

Sterile shunt malfunction

1984 ◽  
Vol 61 (6) ◽  
pp. 1079-1084 ◽  
Author(s):  
David J. Gower ◽  
Jon C. Lewis ◽  
David L. Kelly
Keyword(s):  
Electron Microscopy ◽  
Cellular Response ◽  
Internal Surface ◽  
Giant Cells ◽  
Shunt Malfunction ◽  
Delayed Hypersensitivity ◽  
Silicone Implants ◽  
Content Type ◽  
Joint Implants ◽  
Delayed Hypersensitivity Reaction

✓ Recently, a delayed hypersensitivity reaction to silicone plastics has been demonstrated in some patients with breast and joint implants and subcutaneously injected silicone. In this study, the authors examined the internal surface of shunting systems to evaluate the cellular response to implanted silicone plastic. The distal peritoneal tubing from 20 patients with ventriculoperitoneal shunts was examined with a scanning electron microscope. Twelve tubes were removed because of documented distal shunt malfunction and eight for an elective lengthening procedure. Cultures of all tubing were negative. The catheters removed for malfunction contained a variety of cells: sometimes in clumps, sometimes associated with platelets and densely adherent to the silicone tubing wall. In several shunts, giant cells were seen with multiple foot processes adherent to the internal silicone surface. The internal surface of the tubing of two malfunctioning shunts was embedded in electron microscopy plastic and studied with transmission electron microscopy. The cells proved to be neutrophils with no evidence of silicone granules inside the cell bodies. The shunts removed for elective revision showed only a few cells, and those were never associated with platelets. There was proteinaceous material scattered on the internal surface of the tubing, but the cellular response was markedly different from that in malfunctioning shunts. The authors postulate that the findings in malfunctioning shunt tubing represent a delayed hypersensitivity to silicone similar to that seen with other types of silicone implants.

scholarly journals Immunocytochemical localization of histamine in secretory granules of rat peritoneal mast cells with conventional or rapid microwave fixation and an ultrastructural post-embedding immunogold technique.

1992 ◽  
Vol 40 (9) ◽  
pp. 1247-1256 ◽  
Author(s):  
G R Login ◽  
S J Galli ◽  
A M Dvorak
Keyword(s):  
Electron Microscopy ◽  
Mast Cells ◽  
Guinea Pig ◽  
Secretory Granules ◽  
Fixation Method ◽  
Structural Localization ◽  
Thin Sections ◽  
Aldehyde Fixation ◽  
Peritoneal Mast Cells ◽  
Rat Peritoneal Mast Cells

We used a post-embedding immunogold labeling approach to define the fine-structural localization of histamine in rat peritoneal mast cells that were fixed using either standard aldehyde fixation or a fast microwave-aldehyde fixation method. Specimens were processed routinely for electron microscopy. Thin sections were exposed first to guinea pig antihistamine antiserum and then to gold-conjugated goat IgG directed against guinea pig IgG. By transmission electron microscopy, gold particles were localized to the matrix of cytoplasmic granules. Control sections treated with non-immune sera did not show labeling of mast cells. Adsorption of antihistamine antiserum with purified histamine or histamine bound to agarose showed a significant reduction (p less than 0.005) in granule staining. We also confirmed that our isolation procedures yielded functionally competent mast cells which released histamine when stimulated with sheep anti-rat IgE antiserum or with compound 48/80. These studies define the conditions of fixation for electron microscopy that are appropriate for the localization of histamine in the granule matrix of rat peritoneal mast cells.

scholarly journals Midget retinal ganglion cell dendritic and mitochondrial degeneration is an early feature of human glaucoma

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
James R Tribble ◽  
Asta Vasalauskaite ◽  
Tony Redmond ◽  
Robert D Young ◽  
Shoaib Hassan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Animal Models ◽  
Ganglion Cell ◽  
Retinal Ganglion Cells ◽  
Retinal Ganglion Cell ◽  
Ganglion Cells ◽  
Retinal Ganglion ◽  
Face Scanning ◽  
Block Face ◽  
Scanning Electron

Abstract Glaucoma is characterized by the progressive dysfunction and loss of retinal ganglion cells. However, the earliest degenerative events that occur in human glaucoma are relatively unknown. Work in animal models has demonstrated that retinal ganglion cell dendrites remodel and atrophy prior to the loss of the cell soma. Whether this occurs in human glaucoma has yet to be elucidated. Serial block face scanning electron microscopy is well established as a method to determine neuronal connectivity at high resolution but so far has only been performed in normal retina from animal models. To assess the structure–function relationship of early human glaucomatous neurodegeneration, regions of inner retina assessed to have none-to-moderate loss of retinal ganglion cell number were processed using serial block face scanning electron microscopy (n = 4 normal retinas, n = 4 glaucoma retinas). This allowed detailed 3D reconstruction of retinal ganglion cells and their intracellular components at a nanometre scale. In our datasets, retinal ganglion cell dendrites degenerate early in human glaucoma, with remodelling and redistribution of the mitochondria. We assessed the relationship between visual sensitivity and retinal ganglion cell density and discovered that this only partially conformed to predicted models of structure–function relationships, which may be affected by these early neurodegenerative changes. In this study, human glaucomatous retinal ganglion cells demonstrate compartmentalized degenerative changes as observed in animal models. Importantly, in these models, many of these changes have been demonstrated to be reversible, increasing the likelihood of translation to viable therapies for human glaucoma.

scholarly journals Decidual PTEN expression is required for trophoblast invasion in the mouse

2010 ◽  
Vol 299 (6) ◽  
pp. E936-E946 ◽  
Author(s):  
Marie-Noëlle Laguë ◽  
Jacqui Detmar ◽  
Marilène Paquet ◽  
Alexandre Boyer ◽  
JoAnne S. Richards ◽  
...  
Keyword(s):  
Glycogen Synthase ◽  
Mammalian Target Of Rapamycin ◽  
Giant Cells ◽  
Pten Expression ◽  
Abnormal Development ◽  
Trophoblast Invasion ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Fetal Mortality ◽  
Altered Expression ◽  
Decidual Cells

Trophoblast invasion likely depends on complex cross talk between the fetal and maternal tissues and may involve the modulation of phosphatidylinositol 3-kinase (PI3K)/AKT signaling activity in maternal decidual cells. In this report, we studied implantation in Ptentm1Hwu/tm1Hwu ;Amhr2tm3(cre)Bhr/+ mice, which lack the PI3K signaling antagonist gene Pten in myometrial and stromal/decidual cells. Primiparous Ptentm1Hwu/tm1Hwu ;Amhr2tm3(cre)Bhr/+ mice were found to be subfertile because of increased fetal mortality at e11.5. Histopathological analyses revealed a failure of decidual regression in these mice, accompanied by reduced or absent invasion of fetal trophoblast glycogen cells and giant cells, abnormal development of the placental labyrinth, and frequent apparent intrauterine fetal growth restriction. Unexpectedly, the loss of phosphate and tensin homolog deleted on chromosome 10 (PTEN) expression in Ptentm1Hwu/tm1Hwu ;Amhr2tm3(cre)Bhr/+ decidual cells was not accompanied by a detectable increase in AKT phosphorylation or altered expression or activation of PI3K/AKT downstream effectors such as mammalian target of rapamycin or glycogen synthase kinase-3β. Terminal deoxynucleotidyl transferase-mediated nick end labeling and bromodeoxyuridine incorporation analyses attributed to the lack of decidual regression mainly to decreased apoptosis in Ptentm1Hwu/tm1Hwu ;Amhr2tm3(cre)Bhr/+ decidual cells, rather than to increased proliferation. Remodeling of the maternal vasculature was delayed in Ptentm1Hwu/tm1Hwu ;Amhr2tm3(cre)Bhr/+ uteri at e11.5, as evidenced by persistence of vascular smooth muscle and decreased infiltration of uterine natural killer cells. In addition, thickening of the myometrium and disorganization of the muscle fibers were observed before and throughout gestation. Almost all Ptentm1Hwu/tm1Hwu ;Amhr2tm3(cre)Bhr/+ mice failed to carry a second litter to term, apparently attributable to endometrial hyperplasia and uterine infections. Together, these data demonstrate novel roles of PTEN in the mammalian uterus and its requirement for proper trophoblast invasion and decidual regression.

scholarly journals Ultrastructural analysis of the spermatogenesis in the guinea pig (Cavia porcellus)

2016 ◽  
Vol 36 (suppl 1) ◽  
pp. 89-94 ◽  
Author(s):  
Luciana S. Simões ◽  
Rose E.G. Rici ◽  
Phelipe O. Favaron ◽  
Taís Harumi de Castro Sasahara ◽  
Rodrigo S.N. Barreto ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Guinea Pig ◽  
Sexual Development ◽  
Morphological Changes ◽  
Light And Electron Microscopy ◽  
Management Systems ◽  
Cavia Porcellus ◽  
Reproductive Parameters ◽  
Development Stages ◽  
Transmission Electron

Abstract: al for both, the establishment of appropriate management systems, and for the use of new species as animal models. In this study, we used light and electron microscopy to characterize the sexual development stages of the guinea pig (Cavia porcellus) in specimens of 30, 45 and 90 days of age. We observed the differentiation of spermatocytes only through transmission electron microscopy in the leptotene, zygotene and pachytene phases of meiosis, in 30-day-old animals. During puberty, there was differentiation of the germinative epithelium and formation of the acrosome. Spermatozoa, however, were not detected. Thus, we could infer that puberty happens after 45 days of age. Sexual maturity was evident in 90-day-old specimens. Our results showed that changes in the testicular germinative epithelium during the postnatal sexual development in guinea pig led to morphological changes, including the ones related to the development of Leydig and Sertoli cells, which are directly related to puberty. In this work, we provide new morphological subsidies for a better understanding of reproductive parameters of this species, enabling its use as an animal model in the field of the reproductive biology.

scholarly journals Ultrastructural changes of endothelium associated with thrombocytopenia

Blood ◽  
1975 ◽  
Vol 46 (4) ◽  
pp. 567-578 ◽  
Author(s):  
CS Kitchens ◽  
L Weiss
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Guinea Pig ◽  
Adult Male ◽  
Ultrastructural Changes ◽  
Endothelial Surface ◽  
Endothelial Junctions ◽  
The Relationship

Abstract In a study of the relationship between thrombocytopenia and increased vascular fragility, changes in the endothelium of capillaries and postcapillary venules of the tongue were examined by electron microscopy. Adult male albino rabbits (4 kg) were maintained thrombocytopenic (platelets less than 20,000/cu mm) up to 24 hr by one to three injections of guinea pig antirabbit platelet serum. Within 6 hr the normal projections and folds of the lumenal surface of the endothelial surface were largely effaced. In addition, the endothelium became thinner. In places, pores and membranous diaphragms were observed. Endothelial junctions appeared normal. Identical findings were observed if rabbits were made thrombocytopenic by administration of intraperitoneal busulfan. Intravenously administered Thorotrast was observed in endothelial cells and in the extravascular spaces within 3 min after injection into thrombocytopenic animals, while it was seen only intravascularly in control rabbits. With the spontaneous restoration of circulating platelets, the endothelium reverted to normal.

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