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PubMed2006

Improved methods for ultracryotomy of CNS tissue for ultrastructural and immunogold analyses.

We examined each step of the protocol for ultracryotomy for central nervous system tissue in order to define and overcome some of the methodological difficulties. The following three steps emerged as critical for the method's success: (1) pretreatment of grids to render them hydrophilic immediately before use; (2) careful collection of ultrathin cryosections during ultracryotomy; (3) removal of the appropriate amount of excess poly(vinyl alcohol)-uranyl acetate (PVA-UA) prior to drying after staining with PVA-UA. By taking account of the three critical steps described above, we succeeded in obtaining ultrathin cryosections, including serial sections, with excellent preservation of ultrastructure, as well as semithin cryosections which are useful for evaluating the quality of the samples and for selecting areas of interest for ultrastructural analysis. Cytoplasmic organelles in neurons and glial cells, and the fine structure of synapses and myelinated fibers were well preserved. The localization of gold particles after immunostaining for astrocytic glutamate transporter (GLAST), metabotropic glutamate receptor 1 (mGluR1) and neurofilament protein was consistent with previous reports and ultrastructure was well-preserved in all cases. These findings should be helpful to researchers wishing to carry out ultrastructural and immunogold analyses of cryosections of nervous tissue.

Animals↗
PubMed2004

Ultrastructure of acidic polysaccharides from the cell walls of brown algae.

We have studied the ultrastructure of acidic polysaccharides from the cell walls of brown algae using a variety of electron microscopy techniques. Polysaccharides from Padina gymnospora present self assembled structures, forming trabecular patterns. Purified fractions constituted by alginic acid and sulfated fucan also form well-organized ultrastructures, but the pattern of organization varies depending on the polysaccharide species. Alginic acid presents sponge-like structures. Sulfated fucan exhibits particles with polygonal forms with a polycrystalline structure. These particles are in fact constituted by sulfated fucan molecules since they are recognized by a lectin specific for alpha-l-fucosyl residues. X-ray microanalysis reveal that S is a constituent element, as expected for sulfated groups. Finally, an exhaustive purified sulfated fucan shows the same ultrastructure formed by polygonal forms. Furthermore, elemental analyses of acidic polysaccharides indicate that they retain Zn, when algae were collected from a contaminated area. This observation is supported by direct quantification of heavy metal in the biomass and also in the solubilized polysaccharides compared with the algae from a non-contaminated site. We conclude that these molecules have specific ultrastructure and elemental composition; and act as metal binder for the nucleation and precipitation of heavy metals when the algae are exposed to a metal contaminated environment.

Alginates↗
PubMed2005

Effect of ultrastructural changes on the toughness of bone.

The ultrastructure of bone can be considered as a conjunction between the biology and the biomechanics of the tissue. It is the result of cellular and molecular activities of bone formation, and its organization dominates the mechanical behavior of bone. Following this perspective, the objective of this review is to provide a current understanding of bone ultrastructure and its relationships with the toughness of the tissue. Therefore, we first provide a discussion on the organization of bone constituents, namely collagen, mineral, and water. Then, we present evidence on how the toughness of bone relates to its ultrastructure through the formation of micro damage. In addition, attention is given to how damage accumulation serves as a toughening mechanism. Finally, we describe how changes in the ultrastructure-caused by osteogenesis imperfecta, gamma irradiation, fluoride treatment, and aging affect the toughness and competence of bone.

Aging↗
PubMed2005

Alterations induced by glyphosate on lupin photosynthetic apparatus and nodule ultrastructure and some oxygen diffusion related proteins.

The effects of glyphosate on protein metabolism, mesophyll cell ultrastructure and nodule ultrastructure and functioning of Lupinus albus cv. Multolupa inoculated with Bradyrhizobium sp. (Lupinus) were investigated. Young leaves and nodules were especially affected because these organs act as sinks of the herbicide. The alterations on nodular and chloroplast ultrastructure varied depending on herbicide concentration and time of exposure. After 3 days of 2.5 mM glyphosate application some toxic effects were detected. The most important alterations on nodules were the progressive cellular degradation of plant and bacteroidal cytosol and the rupture of bacteroidal membrane, whilst the peribacteroid membrane of the symbiosomes was preserved. This is the first report on the effect of glyphosate on legume-nodule ultrastructure. Glyphosate inhibited B. sp. (Lupinus) growth at concentrations higher than 62.5 microM. In the mesophyll cells, gradual disorganization of grana and intergrana was observed, loosing the parallel alignment with the chloroplast axis. As in nodules, degradation of membrane systems was observed, with the deformation, and even the rupture, of the tonoplast. These progressive effects were similar to those described in senescence processes. The adverse effects produced on infected zone can be due both to a direct effect of the herbicide on microsymbiont and to an indirect effect of glyphosate action on photosynthetic apparatus. Glyphosate produced changes in nodule cytosol and bacteroid proteins content and polypeptide pattern of leaves and nodules. With respect to proteins related to the oxygen diffusion mechanism, a large decrease in leghemoglobin and glycoproteins (recognized by antibodies MAC236 and MAC265) content was detected, which suggests that the oxygen diffusion mechanisms were also affected by glyphosate.

Diffusion↗
PubMed2007

The effectiveness of the stereomicroscopic evaluation of embryo quality in vitrified-warmed porcine blastocysts: an ultrastructural and cell death study.

The objective of this study was to analyze the validity of the stereomicroscopic evaluation of vitrified-warmed (V-W) porcine blastocysts. Unhatched blastocysts were obtained from Large-white gilts (n=10). Blastocysts (n=156) were vitrified using the Open Pulled Straw technology. After warming, V-W blastocysts were cultured for 24h (V24). Then, their developmental progression was morphologically assessed by stereomicroscopy and classified as: V24 viable re-expanded blastocysts; V24 viable hatched blastocysts or V24 degenerated. Blastocysts which re-expanded or hatched after warming were considered viable. Some fresh blastocysts were not vitrified and were evaluated after 24h in culture (F24). By stereomicroscopic analysis all the fresh blastocysts were considered viable. Some F24, V24 re-expanded viable, V24 hatched viable and V24 degenerated blastocysts were processed for transmission electron microscopy (n=13, 19, 9 and 9, respectively) or assessed by TUNEL for cell-death evaluation (n=16, 21, 11 and 21, respectively). All V24 hatched blastocysts showed similar ultrastructure to fresh blastocysts. However, some V24 re-expanded blastocysts considered viable (6/19) revealed ultrastructural alterations. Degenerated V24 blastocysts showed ultrastructural disintegration. Hatched V24 blastocysts did not differ (p>0.05) from F24 hatched blastocysts with regard to the ratio of dead cells (2.8+/-0.5% versus 1.9+/-0.3%, respectively). However, V24 expanded blastocysts had higher (p<0.01) cell death levels (4.3+/-3.4%) than those observed in the F24 expanded blastocysts (1.1+/-0.3%). The degenerated blastocysts showed the highest cell-death index (19.4+/-6.3%). In summary, V-W blastocyst hatching during in vitro culture appears to coincide with good ultrastructure and low cell-death index, suggesting that the hatching rate assessed by stereomicroscopy is more appropriate than embryo re-expansion for an evaluation of V-W blastocyst quality.

Animals↗
PubMed2005

In vivo studies on toxin accumulation in liver and ultrastructural changes of hepatocytes of the phytoplanktivorous bighead carp i.p.-injected with extracted microcystins.

Phytoplanktivorous bighead carp were injected i.p. with extracted microcystins (mainly MC-RR and -LR) at two doses, 200 and 500 MC-LReq.microg kg(-1) bw, and the changes in extractable MCs in liver and in the ultrastructure of hepatocytes were studied at 1, 3, 12, 24 and 48 h after injection. Quantitative and qualitative determinations of MCs in the liver were conducted by HPLC and LC-MS, respectively. MC concentration in the liver reached the maxima at 12h (2.89 microg MCsg(-1) dry weight at the lower dose) or at 3h (5.43 microg MCsg(-1) dry weight at the higher dose) post-injection, followed by sharp declines afterwards, whereas the ultrastructural changes of hepatocytes in both dose groups suggest progressive increases in severity toward the directions of apoptosis and necrosis from 1 to 24h, respectively. There were two new findings in fish: widening of intercellular spaces was among the early ultrastructural changes induced by MCs and ultrastructural recovery of hepatocytes was evident at 48 h post-injection in both dose groups. Both the present and previous studies suggest that with in vivo or in vitro exposure to microcystins, hepatocyte damage in fish tends to proceed toward the direction of apoptosis at lower MC concentrations but toward the direction of necrosis at high MC concentrations. The temporal dynamics of MCs in the liver suggest that bighead carp may have a mechanism to degrade or bind MC-LR actively after it enters the blood system.

Animals↗
PubMed2004

Ultrastructural evaluation of the protective effect of nitroglycerin in preservation-reperfusion injury of rat lungs.

AIM OF STUDY: Nitric oxide (NO) has been reported as a favorable protective supplement in donor lung preservation, but related ultrastructural studies are rare in the literature. This study was performed to assess the ultrastructural changes and to evaluate the protective effect of NO as donor nitroglycerin (NTG) treatment of ischemia-reperfusion injury in rat lungs. MATERIALS AND METHODS: Fifteen Sprague-Dawley rats weighing 300 to 350 g were used in this study. The NTG group (n = 5) used intravenous administration followed by mixture in the University of Wisconsin (UW) solution. For the non-NTG group (n = 5), we injected the same amount of normal saline intravenously followed by admixture in the UW solution. The heart-lung blocks were removed, weighed, and kept in UW solution for 24 hours at 10 degrees C. Reperfusion using human blood diluted in Krebs-Hensleit solution was done for 60 minutes. For the control group (n = 5), we injected the same amount of normal saline intravenously, and removed the lungs with no preservation and reperfusion procedures. RESULTS: The non-NTG group showed multiple patchy areas of alveolar collapse with marked swelling and destruction of type I epithelial cells, loss of type II cell surfactant granules, endothelial swelling and papillary projection, interstitial edema, and alveolar macrophages with active phagocytosis of the destroyed materials. The NTG group showed similar ultrastructural changes, but in a lesser severity compared with the non-NTG group. CONCLUSION: Administration of the NTG reduced the ischemia-reperfusion injury in the rat donor lungs. Ultrastructural examination was an effective tool to evaluate the protective effect of NTG in ischemia-reperfusion procedures of donor lungs.

Animals↗
PubMed2002

Transmission electron microscopic observations on ultrastructural damage in juvenile Schistosoma mansoni caused by artemether.

Artemether, a derivative of the antimalarial artemisinin, has been shown to induce rapid and extensive alteration to the tegument of juvenile Schistosoma japonicum, S. mansoni and S. haematobium. Less is known with regard to ultrastructural damage caused by artemether; therefore, the present work was designed to assess the damage in juvenile S. mansoni. Mice infected with S. mansoni were treated intragastrically with a single dose of 400 mg/kg artemether 21 days post-infection. Between 8 h and 14 days after treatment groups of two mice were sacrificed, and schistosomula recovered for transmission electron microscopic observations. Ultrastructural damage was seen in the tegument, subtegumental musculature, parenchymal tissues and gastrodermis. It was already apparent 8 h after drug administration and increased gradually to reach a peak, 7 days post-treatment. Tegumental alterations were characterised by swelling, vesiculation and degeneration of sensory structures. Damage in subtegumental musculature, parenchymal tissues and gastrodermis included swelling, focal or extensive lysis, and decrease in granular endoplasmatic reticulum. Fourteen days after treatment ultrastructural damage was still seen in most schistosomula, however, there was partial repair in some specimens. The ability of artemether to cause extensive ultrastructural damage to juvenile S. mansoni correlates with its schistosomicidal effects and confirms earlier findings with S. japonicum.

Animals↗
PubMed1992

An ultrastructural study of the developing urogenital tract in early human fetuses.

OBJECTIVES: This study examines the gonoducts during the ambisexual stage of human fetal development to define their ultrastructural characteristics, including the origin and antomic relationship of the mesonephric and paramesonephric ducts during gonoductal development. STUDY DESIGN: The reproductive tracts from five fetuses ranging in gestational age from 35 to 45 days were processed for ultrastructural examination. The developing mesonephric ducts, paramesonephric ducts, and their surrounding mesenchyme were studied with a Phillips 300 transmission electron microscope. RESULTS: The mesonephric ducts and paramesonephric ducts have distinctive cytoplasmic and cell surface ultrastructural characteristics, as well as different morphologic patterns of epithelial-mesenchymal interaction. Cephalad portions of mesonephric ducts and paramesonephric ducts are separated by mesenchyme, but more caudal aspects move progressively closer until they are juxtaposed but separate. CONCLUSIONS: Early mesonephric ducts and paramesonephric ducts may be distinguished because of their distinctive ultrastructural features; epithelial-mesenchymal interaction may be important in their differentiation and maintenance; both gonoducts retain their morphologic identity throughout, supporting their separate origins.

Cell Nucleolus↗
PubMed2000

Histologic and ultrastructural evaluation of fresh and frozen-thawed human ovarian xenografts in nude mice.

OBJECTIVE: To compare histologic and ultrastructural characteristics of fresh and frozen-thawed human ovarian cortical tissue grafted into nude mice. DESIGN: Experimental prospective study. SETTING: An academic research environment. PATIENT(S): Ovarian biopsy specimens were obtained from 13 women undergoing laparoscopy for tubal ligation or infertility. ANIMAL(S): Forty nude mice. INTERVENTION(S): A minilaparotomy was performed to place fresh and frozen-thawed ovarian grafts subcutaneously (sc) or intraperitoneally (ip). Removal of the ovarian grafts was performed at 24 days. MAIN OUTCOME MEASURE(S): [1] the follicular population, [2] fibrosis, [3] vascularization of the grafted tissue, and [4] ultrastructural evaluation. RESULT(S): A greater fibrosis relative surface area was noted in frozen-thawed transplanted tissue than in fresh transplants. Regardless of this fibrosis, a similar follicular density was observed in fresh and frozen-thawed ovarian tissue 24 days after transplantation. Active angiogenesis was proved by both immunohistochemical study of the vascular endothelial growth factor and morphometric study of the vascular network. Normal ultrastructural characteristics were noted in frozen-thawed ovarian biopsies. CONCLUSION(S): Angiogenesis allows implantation of the graft even if it has been cryopreserved and thawed similarly to implantation of fresh tissue. The greater fibrosis observed in grafts after cryopreservation and implantation does not seem to affect the primordial and primary ovocyte population and their ultrastructural characteristics, but further studies must be conducted to prove that after cryopreservation and transplantation, ovocytes may achieve full maturation and fertilization.

Animals↗
PubMed1981

Ultrastructural changes in human endometrium with copper and nonmedicated IUDs in utero.

Scanning and transmission electron microscopy were used for a study of the surface and glandular ultrastructure of human endometrium in the presence of different types of IUDs at comparable phases of the menstrual cycle. The aim of the study was to compare the effect of the nonmedicated with the copper and multiload copper devices to further explain the differences in their contraceptive potencies and their mechanism of action. The endometrium was evaluated at and away from the IUD; emphasis was put on the ultrastructure of endometrial gland openings, secretory activity, cellular glycogen content, ciliated cells, microvillous pattern, and kinocilia. The changes of the surface ultrastructure of the endometrium in the presence of copper IUDs were more extensive in this study than those previously reported. There seems to be a direct relationship between the amount of copper incorporated in the device, the degree of ultrastructure changes, and the area of endometrium involved. Copper devices affect the endometrial cells away from the IUD. The altered secretory function with disturbed macroapocrine secretion, the abnormality of ciliated cells, and the defective microvillous growth seem to interfere with the physiologic and functional integrity of the endometrium, reducing the chances of contraception in the presence of copper IUDs.

Cilia↗
PubMed1998

An electron microscope study of the axonemal ultrastructure in human spermatozoa from male smokers and nonsmokers.

OBJECTIVE: To investigate possible abnormalities or deterioration of the sperm axonemal ultrastructure in men who have smoked a large quantity of cigarettes (> 20 per day) for a prolonged period. DESIGN: Semen specimens were collected by patients via masturbation; qualitative characteristics of the sperm were assessed and ultrastructural analysis of the sperm axoneme was performed using standard operating procedures for electron transmission microscopy. SETTING: The Andrology Institute of Lexington, Lexington, Kentucky, and the Department of Histology and Embryology, University of Salonika, Greece (collaborative effort). PATIENT(S): Twenty-nine men (mean age +/- SD, 30.7 +/- 2.1 years) who smoked a mean (+/- SD) of 30.7 +/- 2.1 cigarettes per day for 10.7 +/- 0.7 years and 15 men who never smoked (mean age +/- SD, 30.4 +/- 2.2 years) participated in this study. MAIN OUTCOME MEASURE(S): Ultrastructural organization of the sperm axoneme in male smokers and nonsmokers. RESULT(S): Changes in the number and the arrangement of axonemal microtubules were noted in the smoker group when compared to the nonsmoker group. The incidence of axonemal abnormalities was higher in spermatozoa from smokers compared with that in spermatozoa from nonsmokers. CONCLUSION(S): Smoking a large quantity of cigarettes per day, under the conditions of the current study, severely affected the ultrastructure of the flagellum and, more specifically, it affected the axoneme of the human spermatozoon.

Humans↗
PubMed2003

The ultrastructural architecture of the adult Schistosoma japonicum tegument.

The tegument of the adult blood fluke Schistosoma japonicum is in direct contact with the host blood and immune systems. A comprehensive understanding of the ultrastructure of the tegument is crucial to the understanding of how the parasite maintains itself within the mammalian host. Important functions such as nutritional uptake and immune evasion are suspected functions of the tegument and this review discusses these aspects and presents some insights into some of these crucial functions. Transmission electron microscopy has allowed the identification of ultrastructural features of the adult S. japonicum, some of which differ from the reported features of other schistosome species. Morphological differences within the tegument of the adult S. japonicum are noted between sexes, among different regions of the worms and between aspects along the length of the parasite. Differences included variations in the ultrastructure, size and number of tegumental bodies and mitochondria within the matrix, and differences in the relative area of the apical surface of the tegument. Functions of the various components of the tegument matrix and specialised functions of different regions of the male and female parasites are discussed based on ultrastructural findings and previously reported biochemical and molecular data.

Animals↗
PubMedDate not supplied

Alterations in ultrastructure and c-met expression in a case of ocular epithelial dysplasia following topical mitomycin C treatment.

PURPOSE: Topical mitomycin C (MMC) administration is reportedly effective in treating ocular surface neoplasms such as squamous cell carcinoma. We treated a case of ocular epithelial dysplasia that had spread too diffusely to be completely removed. We examined the ultrastructure of and c-met (hepatocyte growth factor receptor) expression in dysplastic epithelial cells from this case to evaluate the efficacy of MMC treatment. METHODS: Specimens of dysplastic epithelial tissue from the corneo-limbal region of a 62-year-old man were obtained before and after topical application of MMC. Specimens were examined ultrastructurally and immunohistochemically with an antibody against human c-met. RESULTS: Following topical application of MMC, the dysplastic epithelium exhibited multilayered epithelial cells similar to those seen before treatment. However, ultrastructural examination showed tight interdigitation between neighboring cells, with no intercellular spaces. Also, the marked immunoreactivity to c-met in the dysplastic epithelial cells before MMC treatment was decreased after treatment. CONCLUSIONS: Ultrastructural observations indicated a restoration of epithelial cellular differentiation following MMC application. The expression of c-met protein was also reduced. Thus, topical MMC was effective in treating epithelial dysplasia of the ocular surface, with no recurrence 15 months post-therapy.

Administration, Topical↗
PubMed2000

Morphological and ultrastructural studies of some acritarchs from the Lower Cambrian Lükati Formation, Estonia.

Six acritarch species from the Lükati Formation were studied using a combination of techniques, including transmitted light, scanning electron (SEM) and transmission electron (TEM) microscopy. New details of wall ultrastructure, surface microsculpture and internal morphology of the vesicle and processes significantly add to the previously known morphological features and increase the understanding of the form-genera Archaeodiscina, Globosphaeridium, Comasphaeridium, Skiagia, Tasmanites and Leiosphaeridia. Examination of microfossils using TEM revealed a substantial variation in wall ultrastructure among acritarchs. The diversity includes four structural types of vesicle wall in addition to their single- and multi-layered structure and the variable thickness of the wall. These are: electron-tenuous and fibrous; electron-dense and homogeneous; electron-dense and homogeneous but perforated by radial canals; and composite laminated structure. Morphologically recognised groupings of acritarchs (acanthomorphic, disphaeromorphic, sphaeromorphic) and tasmanitid taxa appear to be characterised by particular features of the wall structure, although the wall structure in itself may not be directly indicative of systematic relationships. Structurally diverse vesicle walls are observed in Tasmanites and Leiosphaeridia, taxa that both have been interpreted, based on other lines of evidence, to be of prasinophycean (green algal) affinities. The distinct wall ultrastructure of the Leiosphaeridia studied is similar to that of extant green algal genera, which provides evidence that some Cambrian leiosphaerids were chlorophycean algae, probably related to the Order Chlorococcales. Previous research and interpretations of the wall ultrastructure are also briefly discussed.

Journal Article↗
PubMed1998

Ultrastructural changes in fish gills as biomarker to assess small stream pollution.

In order to verify the principal suitability of gill ultrastructure as a biomarker, semi-field studies with two endigoneous fish, trout (Salmo trutta f. fario) and loach (Barbatula barbatula), were performed. The fish were exposed in flow-through systems to one heavily polluted (Körsch) and one lightly polluted small stream (Krähenbach) in South-West Germany. Ultrastructural responses in gills were correlated with limnological and chemical data recorded over a 2 year period in each stream. After 8 weeks of exposure to the heavily polluted stream, fish showed ultrastructural changes in the gills, such as cell proliferation, dilation of the endoplasmic reticulum, hyperplasia, hypersecretion, and epithelial lifting in chloride, epithelial, and mucus cells. The results of the study demonstrate that ultrastructural reactions in the gills of fish kept under semi-field conditions are potentially useful biomarkers indicating small stream pollution.

Animals↗
PubMed1980

Parosteal osteogenic sarcoma. Ultrastructural observations in three cases.

Ultrastructural study of three parosteal osteogenic sarcomas showed this type of tumor to contain numerous myofibroblasts. These cells were admixed with occasional cells resembling osteoblasts and fibroblasts. Cartilaginous areas showed the typical arrangement of cartilage cells embedded in a dense collagen matrix. Ultrastructural examination of a recurrent lesion revealed the presence of numerous undifferentiated cells as well as the types of cells just described. In addition, desmosomes were evident between the more undifferentiated cells. The ultrastructural study of these tumors shows that parosteal osteogenic sarcomas are ultrastructurally a distinctive type of osteogenic sarcoma.

Adolescent↗
PubMed1981

Angiolipomas: an ultrastructural and clinicopathological study.

The clinicopathologic features of 50 noninfiltrating angiolipomas are presented, with a detailed ultrastructural study of five cases and immunoflourescence study of one case. The clinical presentation, including age, location, and associated symptoms, is discussed. Pertinent light microscopic findings, including features helpful in diagnosing borderline lesions, are described. The first ultrastructural and immunofluorescence study of this entity is presented. Among various ultrastructural findings, there appear to be decreased numbers of Weibel-Palade bodies in the endothelial cells of all angiolipomas studied. The relationship of Weibel-Palade bodies to the functional state of the cell and their possible procoagulative effect are discussed. Immunofluorescence and ultrastructural studies further suggest that endothelial disruption and endothelial fibrinogen contribute to the fibrin thrombus formation typically found in angiolipomas.

Adipose Tissue↗