Ultrastructural Studies on the Corneal Superficial Epithelium of Rats by in vivo Cryofixation with Freeze Substitution

1995 ◽  
Vol 27 (5) ◽  
pp. 286-295 ◽  
Author(s):  
Hai-Bo Chen ◽  
Shigeki Yamabayashi ◽  
Bo Ou ◽  
Shinichi Ohno ◽  
Shigeo Tsukahara
Keyword(s):  
Freeze Substitution ◽  
Ultrastructural Studies ◽  
Superficial Epithelium

Probing the ultrastructure of the mitotic and meiotic spindle in eggs: An expeditious approach based on semi-thin (0.25 μm) serial sections

1983 ◽  
Vol 41 ◽  
pp. 552-555
Author(s):  
Conly L. Rieder ◽  
S. Bowser ◽  
R. Nowogrodzki ◽  
K. Ross ◽  
G. Sluder
Keyword(s):  
Small Sample Size ◽  
Small Sample ◽  
Meiotic Spindle ◽  
Serial Sections ◽  
Mitotic Apparatus ◽  
Thin Sections ◽  
Cell Cycles ◽  
Ultrastructural Studies

Eggs have long been a favorite material for studying the mechanism of karyokinesis in-vivo and in-vitro. They can be obtained in great numbers and, when fertilized, divide synchronously over many cell cycles. However, they are not considered to be a practical system for ultrastructural studies on the mitotic apparatus (MA) for several reasons, the most obvious of which is that sectioning them is a formidable task: over 1000 ultra-thin sections need to be cut from a single 80-100 μm diameter egg and of these sections only a small percentage will contain the area or structure of interest. Thus it is difficult and time consuming to obtain reliable ultrastructural data concerning the MA of eggs; and when it is obtained it is necessarily based on a small sample size.We have recently developed a procedure which will facilitate many studies concerned with the ultrastructure of the MA in eggs. It is based on the availability of biological HVEM's and on the observation that 0.25 μm thick serial sections can be screened at high resolution for content (after mounting on slot grids and staining with uranyl and lead) by phase contrast light microscopy (LM; Figs 1-2).

Osseointegration interface of calcified bone and endosseous implants

1992 ◽  
Vol 50 (2) ◽  
pp. 1096-1097
Author(s):  
K.E. Krizan ◽  
J.E. Laffoon ◽  
M.J. Buckley
Keyword(s):  
Structure And Function ◽  
Titanium Implants ◽  
En Bloc ◽  
Endosseous Implants ◽  
Ultrastructural Studies ◽  
The Past ◽  
Cacodylate Buffer ◽  
One Year ◽  
And Function

With increase use of tissue-integrated prostheses in recent years it is a goal to understand what is happening at the interface between haversion bone and bulk metal. This study uses electron microscopy (EM) techniques to establish parameters for osseointegration (structure and function between bone and nonload-carrying implants) in an animal model. In the past the interface has been evaluated extensively with light microscopy methods. Today researchers are using the EM for ultrastructural studies of the bone tissue and implant responses to an in vivo environment. Under general anesthesia nine adult mongrel dogs received three Brånemark (Nobelpharma) 3.75 × 7 mm titanium implants surgical placed in their left zygomatic arch. After a one year healing period the animals were injected with a routine bone marker (oxytetracycline), euthanized and perfused via aortic cannulation with 3% glutaraldehyde in 0.1M cacodylate buffer pH 7.2. Implants were retrieved en bloc, harvest radiographs made (Fig. 1), and routinely embedded in plastic. Tissue and implants were cut into 300 micron thick wafers, longitudinally to the implant with an Isomet saw and diamond wafering blade [Beuhler] until the center of the implant was reached.

scholarly journals A Comprehensive Review on Eryptosis

2016 ◽  
Vol 39 (5) ◽  
pp. 1977-2000 ◽  
Author(s):  
Etheresia Pretorius ◽  
Jeanette N. du Plooy ◽  
Janette Bester
Keyword(s):  
Current Knowledge ◽  
Cell Model ◽  
Health Indicators ◽  
Comprehensive Overview ◽  
Ultrastructural Studies ◽  
Important Health ◽  
Membrane Changes ◽  
Cell Model System ◽  
Cell Changes

Erythrocytes (RBCs) are extremely sensitive cells, and although they do not have nuclei and mitochondria, are important health indicators. This is particularly true because, during inflammation, whether it is systemic or chronic, the haematological system is constantly exposed to circulating inflammatory mediators. RBCs have a highly specialized and organized membrane structure, which interacts and reacts to inflammatory molecule insults, and undergo programmed cell death, similar to apoptosis, known as eryptosis. Over the past years, eryptosis studies have focussed on determining if membrane changes have occurred, particularly whether a phosphatidylserine (PS) flip, Ca2+ leakage into the cell, changes to ceramide and cell shrinkage have occurred. Mostly, flow cytometry is used, but confocal microscopy and ultrastructural studies also confirm eryptosis. Here, we provide a comprehensive overview of eryptosis, where we revisit the biochemical process of the process, review all literature in PUBMED, that is shown under the search word, “eryptosis”, and also discuss current methodologies to determine the presence of eryptosis; included in the discussion of the methodologies, we discuss a pitfalls section for each method. This paper is therefore a comprehensive synopsis of current knowledge of eryptosis and discusses how RBCs may provide an essential in vivo cell model system to study not only inflammation in disease, but also track disease progression and treatment regimes.

Ultrastructural Study Of Experimental Venous Thrombosis

1981 ◽  
Author(s):  
D P Thomas ◽  
R E Merton ◽  
K F Hiller ◽  
D Hockley
Keyword(s):  
Vessel Wall ◽  
Direct Action ◽  
Venous Stasis ◽  
Endothelial Lining ◽  
Jugular Veins ◽  
Ultrastructural Studies ◽  
Platelet Deposition ◽  
Scanning Electronmicroscopy ◽  
Venous Segment

Venous stasis is known to be a necessary but usually not a sufficient cause of venous thrombogenesis. The nature of the additional factor(s) required is uncertain, but the two most likely candidates are local generation of thrombin and vessel wall damage. Autopsy studies show that most venous thrombi develop in apparently normal vessels, although this evidence is based primarily on light microscopy. If thrombin generation is the additional factor, it is uncertain whether such thrombin acts solely on the blood or also damages the endothelium, leading to platelet deposition on exposed subendothelium. We studied the effect of locally injected thrombin on the jugular veins of rabbits, using transmission and scanning electronmicroscopy. One unit of thrombin was sufficient to clot blood contained in an isolated venous segment within a few minutes. The thrombus so formed was then embolised and autologous 11 indium-labelled platelets were injected. Blood flow was re-established for 30 minutes, following which the venous segment was fixed in situ and removed for study.We found no evidence of significant vessel wall damage, as judged by ultrastructural studies or the deposition of labelled platelets. At least 10 u. of injected thrombin were required before the radioactivity in the thrombosed segment exceeded that found in a control vein. Even then, the endothelial lining appeared intact by electronmicroscopy. Following administration of aspirin (10 mg/kg) there was a marked increase in radioactivity present in the thrombosed venous segment, suggesting that inhibition of vessel wall cyclo-oxygenase had led to increased platelet deposition. We conclude that a fresh stasis thrombus resulting from the direct action of thrombin on platelets and fibrinogen does not damage the endothelium, which appears to be relatively resistant in vivo to even high local concentrations of thrombin.

scholarly journals The Role of Plant Growth Regulators in the Development of in vitro Flowering, Histology and Ultrastructural Studies in Impatiens balsamina cv. Dwarf Bush

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
N. MOHAMED ◽  
R.M. TAHA ◽  
U.N.A.A. RAZAK ◽  
H. ELIAS
Keyword(s):  
Plant Growth ◽  
In Vitro Flowering ◽  
Direct Organogenesis ◽  
Stem Explants ◽  
Petiole Explants ◽  
Culture Techniques ◽  
Ultrastructural Studies ◽  
Impatiens Balsamina

ABSTRACT: An efficient protocol for in vitro flowering was successfully established for Impatiens balsamina cv Dwarf Bush, an important medicinal plant, through tissue culture techniques. Shoot, stem and petiole explants obtained from 4 week-old aseptic seedlings cultured on MS medium supplemented with different concentrations of plant growth regulator (PGR) were used for in vitro flower induction. Gibberellic acid (GA3), benzylaminopurine (BAP) and kinetin (Kin) treatment singly applied in MS media (pH 5.8), could all stimulate flowering at 23-26 oC with photoperiod of 16 hours light and 8 hours dark. It was observed that shoot explants were more responsive than stem explants in floral formation. Regeneration was achieved via direct organogenesis. For shoot explants, the treatment that induced the highest rate of in vitro flowering (7.30 ± 0.16 flowers per plantlet) was 1.0 mg L-1 GA3. Ultrastructural and histological analysis of in vivo and in vitro flowers were done to discover any somaclonal variation. This research described a simple protocol for rapid in vitro flowering that will be very beneficial for further breeding, cytological and molecular biology research.

Detection of injected fluorescence-conjugated IgG in living mouse organs using “in vivo cryotechnique” with freeze-substitution

2005 ◽  
Vol 66 (4) ◽  
pp. 173-178 ◽  
Author(s):  
Nobuo Terada ◽  
Nobuhiko Ohno ◽  
Zilong Li ◽  
Yasuhisa Fujii ◽  
Takeshi Baba ◽  
...  
Keyword(s):  
Freeze Substitution ◽  
In Vivo Cryotechnique ◽  
Living Mouse

Schistosoma mansoni: larval damage and role of effector cell(s) in the synergy between vaccine immunity and Praziquantel treatment

Parasitology ◽  
1991 ◽  
Vol 103 (2) ◽  
pp. 207-224 ◽  
Author(s):  
K. P. Piper ◽  
R. F. Mott ◽  
D. J. Hockley ◽  
D. J. McLaren
Keyword(s):  
Effector Cell ◽  
Inflammatory Reactions ◽  
Effector Cells ◽  
Ultrastructural Studies ◽  
Praziquantel Treatment ◽  
Internal Disruption ◽  
Lung Worms ◽  
Extent Of Damage

A number of authors have demonstrated that the schistosomicidal compound, Praziquantel (Pzq), depends for its action upon the immune status of the host (Sabah et al. 1985; Brindley & Sher, 1987; Doenhoff et al. 1987). We have attempted to define the synergistic interaction between immuno- and chemotherapy further, using the murine irradiated vaccine model of schistosomiasis mansoni. In vaccinated mice, resistance operates in the skin but not the lungs; drug targeted towards lung-stage worms exacerbates lung-phase immunity, however, as depicted by the increased number and size of inflammatory reactions in the pulmonary tissues. Parasites are often found trapped within such foci. In the present investigation, light and ultrastructural studies have been utilized to examine the nature and extent of damage inflicted upon lung-stage larvae recovered from day 6 Pzq-treated vaccinated mice. Such studies have revealed that damage involves muscle disorganization, internal disruption and occasionally, loss of the tegument; in the latter case, cells are often seen attached to the denuded lung worms. To identify the crucial cellular effector cell(s) involved in the synergy between immuno- and chemotherapy, cell depletion studies have been performed in vivo. It would appear from these experiments that eosinophils or lymphocytes rather than neutrophils or macrophages are important effector cells in this synergy. Histological studies argue in favour of eosinophils being the key effector cells.

scholarly journals Nitrite attenuates mitochondrial impairment and vascular permeability induced by ischemia-reperfusion injury in the lung

2020 ◽  
Vol 318 (4) ◽  
pp. L580-L591
Author(s):  
Ajay Kumar ◽  
Kentaro Noda ◽  
Brian Philips ◽  
Murugesan Velayutham ◽  
Donna B. Stolz ◽  
...  
Keyword(s):  
Vascular Permeability ◽  
Complex I ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Pulmonary Vascular Permeability ◽  
Ultrastructural Studies ◽  
Mitochondrial Impairment ◽  
Complex I Activity

Primary graft dysfunction (PGD) is directly related to ischemia-reperfusion (I/R) injury and a major obstacle in lung transplantation (LTx). Nitrite ([Formula: see text]), which is reduced in vivo to form nitric oxide (NO), has recently emerged as an intrinsic signaling molecule with a prominent role in cytoprotection against I/R injury. Using a murine model, we provide the evidence that nitrite mitigated I/R-induced injury by diminishing infiltration of immune cells in the alveolar space, reducing pulmonary edema, and improving pulmonary function. Ultrastructural studies support severe mitochondrial impairment in the lung undergoing I/R injury, which was significantly protected by nitrite treatment. Nitrite also abrogated the increased pulmonary vascular permeability caused by I/R. In vitro, hypoxia-reoxygenation (H/R) exacerbated cell death in lung epithelial and microvascular endothelial cells. This contributed to mitochondrial dysfunction as characterized by diminished complex I activity and mitochondrial membrane potential but increased mitochondrial reactive oxygen species (mtROS). Pretreatment of cells with nitrite robustly attenuated mtROS production through modulation of complex I activity. These findings illustrate a potential novel mechanism in which nitrite protects the lung against I/R injury by regulating mitochondrial bioenergetics and vascular permeability.

Ultrastructure of Septa from the Filamentous Fungus Aspergillus Nidulans

1998 ◽  
Vol 4 (S2) ◽  
pp. 1142-1143
Author(s):  
Elizabeth A. Richardson ◽  
Michelle Momany
Keyword(s):  
Aspergillus Nidulans ◽  
Filamentous Fungus ◽  
Freeze Substitution ◽  
Uranyl Acetate ◽  
Temperature Sensitive ◽  
Electron Microscopic ◽  
Genetic Studies ◽  
Ultrastructural Studies ◽  
Microscopic Studies ◽  
Dialysis Membranes

The filamentous fungus Aspergillus nidulans partitions its cells by laying down septa at regularly spaced intervals in response to nuclear division. Physiological and genetic studies of the temperature-sensitive sep mutants have been especially useful in dissecting the regulation of septation. Electron microscopic studies of the sep mutants should be equally useful in dissecting the structural intermediates of septation. In preparation for ultrastructural studies of the sep mutants, we have examined septa in wild-type A. nidulans fixed by freeze substitution.Dialysis membranes were placed on rich medium plates and inoculated with A. nidulans spore suspensions. After 12 hours at 30°C, the dialysis membranes with adhering fungal hyphae were cut into square pieces measuring approximately 5mm on each side. The pieces were plunged into liquid propane and processed according to the procedures of Hoch. Serial sections were cut using a diamond knife and post stained with uranyl acetate and lead citrate.

Sign in / Sign up

Export Citation Format

Share Document