Endodermal formation in blastocytes of the marsupials Isoodon macrousus and Perameles nasuta

1977 ◽  
Vol 25 (2) ◽  
pp. 207 ◽  
Author(s):  
DE Hollis ◽  
AG Lyne
Keyword(s):  
Electron Microscopy ◽  
Outer Surface ◽  
Zona Pellucida ◽  
Morphological Changes ◽  
Light And Electron Microscopy ◽  
Didelphis Virginiana ◽  
Continuous Layer ◽  
Shell Membrane ◽  
American Opossum ◽  
Embryonic Region

Eleven embryos, ranging from partly to fully bilaminar blastocysts, were obtained from the bandicoots I. macrourus and P. nasuta and were examined by light and electron microscopy. The morphological changes which occurred during the differentiation of the endoderm and ectoderm are described. The shell membrane was thinner than it was in unilaminar blastocysts and had a deposit of material of irregular thickness on its outer surface. The mucoid coat and zona pellucida were absent or discontinuous. Endoderm formation was first observed in blastocysts about 1.0 mm in diameter. Cells migrated inwards from regions of thickened protoderm to form a continuous layer of similar flattened cells - the endoderm - beneath the protoderm, which then became the ectoderm. The blastocysts were fully bilaminar when they were 1.5-1.9 mm in diameter. At this stage the ectoderm was composed of two distinct regions, an embryonic region of cuboidal cells and a non-embryonic region of flattened cells resembling the cells of the endoderm. The formation of the endoderm in bandicoots closely resembles that described in other marsupials, except the American opossum Didelphis virginiana in which endoderm cells are released into the blastocoele before they form a continuous layer.

Early embryology af the marsupials Isoodon macrourus and Perameles nasuta

1976 ◽  
Vol 24 (3) ◽  
pp. 361 ◽  
Author(s):  
AG Lyne ◽  
DE Hollis
Keyword(s):  
Electron Microscopy ◽  
Outer Surface ◽  
Zona Pellucida ◽  
Light And Electron Microscopy ◽  
Blastocyst Stage ◽  
Embryonic Cells ◽  
Crystalloid Inclusions ◽  
Early Mouse ◽  
Number Of Cells ◽  
Rabbit Embryos

Twelve embryos, ranging from a four-celled stage to late unilaminar blastocysts, were obtained from the bandicoots I. macrourus and P. nasuta and examined by light and electron microscopy. These early stages covered at least one-quarter of the 12.5-day gestation period. The three non-cellular egg membranes characteristic of marsupials (zona pellucida, mucoid coat and shell membrane) were present, although the zona was sometimes absent or discontinuous in the intermediate and late unilaminar blastocysts examined. At the four-celled stage the blastomeres were close to the zona, but they had lost contact with each other, probably due to the extrusion of yolk, a phenomenon which has been described in other marsupials. The embryo did not increase in diameter until it was composed of at least 75 contiguous cells, which were in contact with the zona. In several of the larger blastocysts the protoderm cells had lost contact with the zona. Subsequently, the number of cells increased considerably and they were flattened against the egg membranes to form the late unilaminar blastocyst stage. Electron microscopy of the protoderm cells revealed the presence of numerous microvilli, particularly on the outer surface, and a range of other structures as great as those found in eutherian mammals. Remnants of spindle bridges were common in one 75-celled embryo. The yolk material in the blastocoele was also composed of a variety of structures, including small crystalloid inclusions composed of hexagonal units about 8-10 nm in diameter. Similar crystalloids have been described in the cells of early mouse and rabbit embryos and in egg and embryonic cells of various amphibians.

Further observations on nucleolar tails in amphibian oocytes

1991 ◽  
Vol 99 (3) ◽  
pp. 515-521
Author(s):  
PEDRO LEÓN ◽  
JAMES KEZER ◽  
ERIC SCHABTACH
Keyword(s):  
Electron Microscopy ◽  
Nuclear Envelope ◽  
Nuclear Membrane ◽  
Outer Surface ◽  
Light And Electron Microscopy ◽  
Nuclear Pores ◽  
Core Component ◽  
Amphibian Species ◽  
Attachment Structures ◽  
Convoluted Tubules

Large oocytes from some amphibian species possess beaded or unbeaded intranuclear tails that penetrate the extrachromosomal nucleoli through a distinct pit in their surface and attach to the central core component Here we show, using light and electron microscopy, that tails anchor nucleoli to the nuclear envelope through intricate attachment structures. These structures are composed of interconnected spherical masses containing highly convoluted tubules and associated extratubular proteins, directly directly in contact with the inner nuclear membrane. Fibers emerging from the nuclear pores seemingly hold the attachment complex in place. Beads on the nucleolar tails are formed by the accumulation of proteins on the outer surface of smooth tubules. The function of these intranuclear tubules is unknown

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 Light and electron microscopy characteristics of the muscle of patients with SURF1 gene mutations associated with Leigh disease

2007 ◽  
Vol 61 (4) ◽  
pp. 460-466 ◽  
Author(s):  
M Pronicki ◽  
E Matyja ◽  
D Piekutowska-Abramczuk ◽  
T Szymańska-Dębińska ◽  
A Karkucińska-Więckowska ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lipid Accumulation ◽  
Morphological Changes ◽  
Light And Electron Microscopy ◽  
Gene Mutations ◽  
Leigh Syndrome ◽  
Typical Feature ◽  
Ultrastructural Changes ◽  
Consistent Feature ◽  
Muscle Changes

Aims:Leigh syndrome (LS) is characterised by almost identical brain changes despite considerable causal heterogeneity. SURF1 gene mutations are among the most frequent causes of LS. Although deficiency of cytochrome c oxidase (COX) is a typical feature of the muscle in SURF1-deficient LS, other abnormalities have been rarely described. The aim of the present work is to assess the skeletal muscle morphology coexisting with SURF1 mutations from our own research and in the literature.Methods:Muscle samples from 21 patients who fulfilled the criteria of LS and SURF1 mutations (14 homozygotes and 7 heterozygotes of c.841delCT) were examined by light and electron microscopy.Results:Diffuse decreased activity or total deficit of COX was revealed histochemically in all examined muscles. No ragged red fibres (RRFs) were seen. Lipid accumulation and fibre size variability were found in 14 and 9 specimens, respectively. Ultrastructural assessment showed several mitochondrial abnormalities, lipid deposits, myofibrillar disorganisation and other minor changes. In five cases no ultrastructural changes were found. Apart from slight correlation between lipid accumulation shown by histochemical and ultrastructural techniques, no other correlations were revealed between parameters investigated, especially between severity of morphological changes and the patient’s age at the biopsy.Conclusion:Histological and histochemical features of muscle of genetically homogenous SURF1-deficient LS were reproducible in detection of COX deficit. Minor muscle changes were not commonly present. Also, ultrastructural abnormalities were not a consistent feature. It should be emphasised that SURF1-deficient muscle assessed in the light and electron microscopy panel may be interpreted as normal if COX staining is not employed.

Glomerulonephropathies in Plasmodium inui-infected rhesus monkey: a primate model and possible applications for human quartan malaria

Parasitology ◽  
2014 ◽  
Vol 141 (12) ◽  
pp. 1638-1645 ◽  
Author(s):  
L. F. NIMRI ◽  
H. N. LANNERS
Keyword(s):  
Electron Microscopy ◽  
Rhesus Monkey ◽  
Mesangial Cells ◽  
Morphological Changes ◽  
Clinical Chemistry ◽  
Light And Electron Microscopy ◽  
Histopathological Changes ◽  
Primate Model ◽  
Nephritic Syndrome ◽  
Plasmodium Inui

SUMMARYNone of the few animal models proposed for the study of human quartan malaria nephritic syndrome have shown complete pathological findings that are similar to those seen in humans. This study investigated the histopathological changes in kidneys in 10 Plasmodium inui infected Macaca mulatta monkeys by light and electron microscopy in order to develop a suitable animal model for human quartan malaria. Ten healthy adult rhesus monkeys were infected with P. inui and clinical chemistry and haematologic tests were done before and after infection. A renal biopsy sample was collected before infection as a baseline control and another biopsy was collected after infection. Histopathological changes examined by light and transmission electron microscopy (TEM) revealed abnormalities in all infected monkeys to variable degrees. Several electron-dense discrete or diffused mesangial deposits, and increase in mesangial cells and matrix were associated with the morphological changes observed by light microscope. This pattern is consistent with membranoproliferative glomerulonephritis type reported in humans infected with Plasmodium malariae. Results strongly support that the P. inui-infected rhesus monkey develop an immune-complex-mediated glomerulonephritis in the course of the infection. Therefore, this experimental model represents a useful tool to better understand the different parameters and the consequences of quartan malaria infections comparable to situations in humans.

scholarly journals AUTOIMMUNE HEPATITIS: MORPHOLOGICAL ASPECTS

2021 ◽  
Vol 5 (1) ◽  
pp. 5-16
Author(s):  
V. M. Tsyrkunov ◽  
◽  
N. I. Prokopchik ◽  
V. P. Andreev ◽  
◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Autoimmune Hepatitis ◽  
Morphological Changes ◽  
Light And Electron Microscopy ◽  
Morphological Aspects

The review presents literature data on the main pathomorphological features of autoimmune hepatitis (AIH) and the findings of light and electron microscopy in the form of photographs and descriptions of different variants of hepatic morphological changes in patients with AIH. Updates to the sections of the AIH classification concerning the etiology and origin of AIH are suggested, clinical examples are given with a description of the morphology features according to the classification specified by the authors.

scholarly journals Relationships between Intraocular Pressure, Effective Filtration Area and Morphological Changes in the Trabecular Meshwork of Steroid-Induced Ocular Hypertensive Mouse Eyes

2022 ◽  
Vol 23 (2) ◽  
pp. 854
Author(s):  
Ruiyi Ren ◽  
Anne A. Humphrey ◽  
David L. Swain ◽  
Haiyan Gong
Keyword(s):  
Electron Microscopy ◽  
Intraocular Pressure ◽  
Trabecular Meshwork ◽  
Inverse Relationship ◽  
Morphological Changes ◽  
Light And Electron Microscopy ◽  
Eye Drops ◽  
Fluorescent Tracers ◽  
Filtration Area ◽  
The Mean

We investigated whether an inverse relationship exists between intraocular pressure (IOP) and effective filtration area (EFA) in the trabecular meshwork (TM) in a steroid-induced ocular hypertensive (SIOH) mouse model and the morphological changes associated with the reduction of EFA. C57BL/6 mice (n = 15 per group) received either 0.1% dexamethasone (DEX) or saline eye drops twice daily for five weeks. IOP was measured weekly. Fluorescent tracers were injected into the anterior chamber to label EFA at the endpoint. Injected eyes were fixed and processed for confocal microscopy. EFA in the TM was analyzed. Light and electron microscopy were performed in high- and low-tracer regions of six eyes per group. The mean IOP was ~4 mm Hg higher in DEX-treated than saline-treated control eyes (p < 0.001) at the endpoint. EFA was reduced in DEX-treated eyes compared to controls (p < 0.01) and negatively correlated with IOP (R2 = 0.38, p = 0.002). Reduced thickness of juxtacanalicular tissue (JCT) and increased abnormal extracellular matrix in the JCT were found to be associated with reduced EFA. Our data confirm the inverse relationship between EFA and IOP, suggesting that morphological changes in the JCT contribute to the reduction of EFA, thus elevating IOP in SIOH mouse eyes.

Morphological Changes in Lipodermatosclerosis and Venous Ulcers: Light Microscopy, Immunohistochemistry and Electron Microscopy

1994 ◽  
Vol 9 (2) ◽  
pp. 48-54 ◽  
Author(s):  
M. Tronnier ◽  
W. Schmeller ◽  
H. H. Wolff
Keyword(s):  
Electron Microscopy ◽  
Immunoelectron Microscopy ◽  
Type Iv Collagen ◽  
Morphological Changes ◽  
Light And Electron Microscopy ◽  
Basal Membrane ◽  
Ultrastructural Localization ◽  
Venous Ulceration ◽  
Type Iv ◽  
Venous Ulcers

Objectives: To demonstrate morphological changes in lipodermatosclerosis (LDS) and venous ulcers by histology, immunohistochemistry, electron microscopy and immunoelectron microscopy. Design: Single patient group study in patients with trophic skin changes in chronic venous insufficiency. Setting: Department of Dermatology, Medical University of Lübeck. Patients: Ten patients with venous leg ulcers. Interventions: Biopsies were taken from areas of LDS and compared with clinically normal-appearing skin of the affected leg and with ulcer tissue. Main outcome measures: Comparison of the morphological features on light and electron microscopy. Results: Superficial dermis. Histologically, the ulcer tissue and LDS skin show dilated tortuous vessels in a glomerulus-like arrangement in the superficial parts of the dermis. Ultrastructurally, the superficial vessels are surrounded by a cuff, which contains amorphous and basal membrane material and is most pronounced in LDS. Immunofluorescence studies reveal ill-defined perivascular staining after incubation with antibodies against fibrin(ogen), laminin and type IV collagen. The exact ultrastructural localization of type IV collagen within the perivascular cuff is observed by immunoelectron microscopy. Deep dermis. In deeper parts of the dermis, the vessels of both ulcer tissue and LDS are surrounded by cellular cuffs with pericytes, fibroblasts and compact collagen bundles. Conclusions: We suggest that the severe morphological changes in LDS and ulcer tissue play an important role in the pathogenesis of venous ulceration.

An unusual blastocyst stage of the marsupial Isoodon macrourus

1977 ◽  
Vol 25 (2) ◽  
pp. 225 ◽  
Author(s):  
AG Lyne ◽  
DE Hollis
Keyword(s):  
Electron Microscopy ◽  
Zona Pellucida ◽  
Light And Electron Microscopy ◽  
Blastocyst Stage ◽  
Cell Divisions

Four blastocysts, identical in size (diameter 1.1 mm) and appearance, were obtained from one uterus of a short-nosed bandicoot I. macrourus and examined by light and electron microscopy. These blastocysts were unusual in that each one had a conspicuous region of protoderm about 0.3-0.5 mm in width and mostly more than one cell thick. The remainder of the protoderm was thin and unilaminar. Cell divisions were more numerous in the thickened region than in the remainder of the protoderm. Some entire cells and blebs of cytoplasm had been shed or were being shed from the thickened region into the blastocoele. The egg membranes were similzr to those of bilaminar blastocysts, the shell membranes being intact and about 1.0 um thick, and the mucoid coat and zona pellucida being discontinuous.

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