An Electron-Microscope Study of the Extranucleolar Bodies during Growth of the Oocyte in the Prepubertal Mouse

1973 ◽  
Vol 12 (1) ◽  
pp. 55-69
Author(s):  
L. A. CHOUINARD
Keyword(s):  
Functional Organization ◽  
Current Knowledge ◽  
Oocyte Nucleus ◽  
Oocyte Growth ◽  
Fibrillar Material ◽  
The Third ◽  
Morphological Findings ◽  
Coiled Bodies ◽  
Differential Gene ◽  
Morphological Expression

The dictyate nucleus of the growing mouse oocyte exhibits, besides the nucleolus, 3 ultrastructurally distinct types of smaller formed entities referred to as extranucleolar bodies. The extranucleolar bodies of the first type (fibrillogranular bodies) consist of intermingled masses made up of closely arranged convoluted fibrils, 6-10 nm in width, interspersed with electrondense granules approximately 15 nm in diameter. The extranucleolar bodies of the second type (fibrillar bodies) are composed of an entanglement of loosely arranged convoluted fibrils 4-10 nm in diameter; such bodies are also characterized by the presence within their mass of irregularly shaped widely scattered islands of varying sizes made up of densely packed fibrillar material exhibiting a somewhat greater electron opacity. The extranucleolar bodies of the third type (coiled bodies) appear to consist of an aggregate of highly contorted threads, the thickness of which varies from 20 to 35 nm; the threads themselves are composed of bundles of fibrils 5 nm thick which are irregularly twisted along their axis. An attempt is made to interpret these morphological findings in the light of current knowledge concerning the architectural and functional organization of the oocyte nucleus in general during the protracted dictyate stage of meiotic prophase. Our observations would be consistent with the view that the various types of extranucleolar bodies are morphological expression - like the puffs of the polytene and the loops or spheroids of the lampbrush chromosomes - of differential gene activity on the part of the localized regions of the chromosomes during oocyte growth.

A light- and electron-microscope study of the oocyte nucleus during development of the antral follicle in the prepubertal mouse

1975 ◽  
Vol 17 (3) ◽  
pp. 589-615
Author(s):  
L.A. Chouinard
Keyword(s):  
Meiotic Prophase ◽  
Functional Organization ◽  
Current Knowledge ◽  
Light And Electron Microscopy ◽  
Antral Follicle ◽  
Mouse Oocyte ◽  
Oocyte Nucleus ◽  
Follicle Development ◽  
Preovulatory Follicle ◽  
Functional Changes

The ordered changes which occur in the structural organization of the mouse oocyte nucelus during the preparatory, the maturative and the preovulatory stages of antral follicle development, have been studied under both light and electron microscopy. All observations have been made on those antral follicles whose development is initiated on postnatal day 14 and completed by postnatal day 28 in prepubertal animals of the ICR albino mouse strain. The formed entities that can be recognized within the oocyte nucleus during that period are the condensing bivalents, the heterochromatic knobs, the nucleolus and the extranucleolar bodies. At the onset of antral follicle development, the highly unravelled dictyate bivalents are seen to take on a lampbrush-type configuration. Subsequent condensation of these lampbursh bivalents appears to be a very gradual and lengthy process that extends over almost the entire period of antral follicle development. The shortening and thickening of the lampbrush bivalents are best interpreted as resulting from the withdrawal of their lateral loop-like projections into the chromosome axes and from the focal aggregation of these axes into compact chromatin masses. Electron-opaque granules, which appear within the oocyte nucleus during the preparatory and maturative follicle stages, are seen to be intimately associated with these condensing bivalents. A number of Feulgen-positive heterochromatic knobs make their appearance in contact with certain bivalents during the preparatory follicle stage. These knobs are not reincorporated as such into the condensing chromatin masses and undergo disintegration and dissolution during the preovulatory follicle stage. The size, shape and ultrastructural features of the nucleolus remain unchanged thoughout the period of antral follicle development. Breakdown and dissolution of the nucleolar mass is a swift process that takes place only in the fully mature preovulatory follicle and more or less concomitantly with the dismantling of the nuclear envelope. The extranucleolar bodies increase noticeably in size during the preparatory and the maturative follicle stages; they shrink in size and undergo dissolution during the preovulatory stage of antral follicle development. An attempt is made to interpret these morphological changes in the light of current knowledge concerning the architectural and functional organization of the oocyte nucleus in general during meiotic prophase. The relevant observational evidence would be consistent with the view that, during antral follicle deveopment, the mouse oocyte nucleus is not, as too often assumed, in a period of arrested evolution; its formed components undergo structural, maturational and functional changes which are of significance not only for the resumption of the first meiotic prophase but also for the early development of the embryo.

Studies on Thrombolysis with Streptokinase

1971 ◽  
Vol 25 (02) ◽  
pp. 354-378 ◽  
Author(s):  
R Gottlob ◽  
L Stockinger ◽  
U Pötting ◽  
G Schattenmann
Keyword(s):  
Electron Microscopy ◽  
Cross Section ◽  
Whole Blood ◽  
Jugular Vein ◽  
Thin Sections ◽  
The Third ◽  
Morphological Findings ◽  
Blood Clots ◽  
Arteries And Veins

SummaryIn vitro whole blood clots of various ages, experimental thrombi produced in the jugular vein of rabbits and human thrombi from arteries and veins were examined in semi-thin sections and by means of electron microscopy.In all types of clots examined a typical course of retraction was found. Retraction starts with a dense excentrical focus which grows into a densification ring. After 24 hours the entire clot becomes almost homogeneously dense; later a secondary swelling sets in.Shortly after coagulation the erythrocytes on the rim of the clot are bi-concave discs. They then assume the shape of crenate spheres, turn into smooth spheres and finally become indented ghosts which have lost the largest part of their contents. In the inner zone, which makes up the bulk of the clot, we observed bi-concave discs prior to retraction. After retraction we see no crenations but irregularly shaped erythrocytes. Once the secondary swelling sets in, the cross-section becomes polygonal and later spherical. After extensive hemolysis we observe the “retiform thrombus” made up of ghosts.Experimental and clinical thrombi present the same morphology but are differentiated from in vitro clots by: earlier hemolysis, immigration of leukocytes, formation of a rim layer consisting of fibrin and thrombocytes, and the symptoms of organization. Such symptoms of organization which definitely will prevent lysis with streptokinase were found relatively late in experimental and clinical thrombi. Capillary buds and capillary loops were never found in clinical thrombi prior to the third month.The morphological findings agree with earlier physical and enzymatic investigations. The observation that phenomena of reorganization occur relatively late and frequently only in the rim areas of large thrombi explains why lytic therapy is possible in some of the chronic obliterations.

scholarly journals Immune response of calves inoculated with proteins ofAnaplasma marginale bound to an immunostimulant complex

2013 ◽  
Vol 22 (2) ◽  
pp. 253-259 ◽  
Author(s):  
Marcela Ribeiro Gasparini ◽  
Rafael Felipe da Costa Vieira ◽  
Denise Amaral Gomes do Nascimento ◽  
João Luis Garcia ◽  
Odilon Vidotto ◽  
...  
Keyword(s):  
Immune Response ◽  
Current Knowledge ◽  
Surface Proteins ◽  
Control Group ◽  
Humoral Immune ◽  
The Third ◽  
Additional Testing ◽  
Major Surface Proteins ◽  
Cattle Herds ◽  
Major Surface

Despite our current knowledge of the immunology, pathology, and genetics of Anaplasma marginale, prevention in cattle is currently based on old standbys, including live attenuated vaccines, antibiotic treatment, and maintaining enzootic stability in cattle herds. In the present study, we evaluated the use of an immunostimulant complex (ISCOMATRIX) adjuvant, associated with a pool of recombinant major surface proteins (rMSP1a, rMSP1b, rMSP4 and rMSP5) to improve the humoral immune response triggered in calves mainly by IgG2. Ten calves were divided in three groups: 4 calves were inoculated with the ISCOMATRIX/rMSPs (G1); 2 calves were inoculated with ISCOMATRIX adjuvant (G2); and 4 calves received saline (G3). Three inoculations were administered at 21-day intervals. In G1, the calves showed significant increases in total IgG, IgG1 and IgG2 levels 21 days after the second inoculation, compared to the control group (p < 0.05), and G1 calves remained above the cut-off value 28 days after the third inoculation (p < 0.05). The post-immunized sera from calves in G1 reacted specifically for each of the rMSPs used. In conclusion, the ISCOMATRIX/rMSPs induced antigen-specific seroconversion in calves. Therefore, additional testing to explore the protection induced by rMSPs, both alone and in conjunction with proteins previously identified as subdominant epitopes, is warranted.

scholarly journals Organization of the Macaque Extrastriate Visual Cortex Re-Examined Using the Principle of Spatial Continuity of Function

2011 ◽  
Vol 105 (1) ◽  
pp. 305-320 ◽  
Author(s):  
T. N. Aflalo ◽  
M.S.A. Graziano
Keyword(s):  
Functional Organization ◽  
Current Knowledge ◽  
Dimensional Space ◽  
Macaque Monkey ◽  
Specific Pattern ◽  
Extrastriate Cortex ◽  
Cortical Function ◽  
Spatial Continuity ◽  
Functional Relationships ◽  
Hierarchical Relationships

How is the macaque monkey extrastriate cortex organized? Is vision divisible into separate tasks, such as object recognition and spatial processing, each emphasized in a different anatomical stream? If so, how many streams exist? What are the hierarchical relationships among areas? The present study approached the organization of the extrastriate cortex in a novel manner. A principled relationship exists between cortical function and cortical topography. Similar functions tend to be located near each other, within the constraints of mapping a highly dimensional space of functions onto the two-dimensional space of the cortex. We used this principle to re-examine the functional organization of the extrastriate cortex given current knowledge about its topographic organization. The goal of the study was to obtain a model of the functional relationships among the visual areas, including the number of functional streams into which they are grouped, the pattern of informational overlap among the streams, and the hierarchical relationships among areas. To test each functional description, we mapped it to a model cortex according to the principle of optimal continuity and assessed whether it accurately reconstructed a version of the extrastriate topography. Of the models tested, the one that best reconstructed the topography included four functional streams rather than two, six levels of hierarchy per stream, and a specific pattern of informational overlap among streams and areas. A specific mixture of functions was predicted for each visual area. This description matched findings in the physiological literature, and provided predictions of functional relationships that have yet to be tested physiologically.

scholarly journals Oral Alterations in Diabetes Mellitus

2018 ◽  
Vol 22 (1) ◽  
pp. 7-14 ◽  
Author(s):  
Smiljka Cicmil ◽  
Irena Mladenović ◽  
Jelena Krunić ◽  
Dragan Ivanović ◽  
Nikola Stojanović
Keyword(s):  
Diabetes Mellitus ◽  
Insulin Secretion ◽  
Insulin Action ◽  
Metabolic Diseases ◽  
Dental Treatment ◽  
Current Knowledge ◽  
Dental Health ◽  
The Third ◽  
Oral Tissue ◽  
Compromised Patients

SummaryDiabetes mellitus is one of the most common chronic diseases which continue to increase in number and significance. It presents the third most prevalent condition among medically compromised patients referring for dental treatment. Diabetes mellitus has been defined as a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. Hyperglycemia leads to widespread multisystem damage which has an effect on oral tissue. The present article summarizes current knowledge regarding the association between diabetes mellitus and oral and dental health.

Action Plan for Australian Birds 2010

2011 ◽  
Author(s):  
Stephen Garnett ◽  
Judit Szabo ◽  
Guy Dutson
Keyword(s):  
Current Knowledge ◽  
Action Plan ◽  
Iucn Red List ◽  
Red List ◽  
International Union ◽  
The Third ◽  
Retrospective Assessment ◽  
Australian Birds ◽  
The Status ◽  
Iucn Red List Criteria

The Action Plan for Australian Birds 2010 is the third in a series of action plans that have been produced at the start of each decade. The book analyses the International Union for Conservation of Nature (IUCN) status of all the species and subspecies of Australia's birds, including those of the offshore territories. For each bird the size and trend in their population and distribution has been analysed using the latest iteration of IUCN Red List Criteria to determine their risk of extinction. The book also provides an account of all those species and subspecies that are or are likely to be extinct. The result is the most authoritative account yet of the status of Australia's birds. In this completely revised edition each account covers not only the 2010 status but provides a retrospective assessment of the status in 1990 and 2000 based on current knowledge, taxonomic revisions and changes to the IUCN criteria, and then reasons why the status of some taxa has changed over the last two decades. Maps have been created specifically for the Action Plan based on vetted data drawn from the records of Birds Australia, its members and its partners in many government departments. This is not a book of lost causes. It is a call for action to keep the extraordinary biodiversity we have inherited and pass the legacy to our children. 2012 Whitley Award Commendation for Zoological Resource.

Zero Morphemes

2018 ◽  
Author(s):  
Eystein Dahl ◽  
Antonio Fábregas
Keyword(s):  
Strict Sense ◽  
Controversial Issues ◽  
Important Ingredient ◽  
Analytical Instruments ◽  
The Third ◽  
Morphological Theory ◽  
The One ◽  
Morphological Expression ◽  
Made In

Zero or null morphology refers to morphological units that are devoid of phonological content. Whether such entities should be postulated is one of the most controversial issues in morphological theory, with disagreements in how the concept should be delimited, what would count as an instance of zero morphology inside a particular theory, and whether such objects should be allowed even as mere analytical instruments. With respect to the first problem, given that zero morphology is a hypothesis that comes from certain analyses, delimiting what counts as a zero morpheme is not a trivial matter. The concept must be carefully differentiated from others that intuitively also involve situations where there is no overt morphological marking: cumulative morphology, phonological deletion, etc. About the second issue, what counts as null can also depend on the specific theories where the proposal is made. In the strict sense, zero morphology involves a complete morphosyntactic representation that is associated to zero phonological content, but there are other notions of zero morphology that differ from the one discussed here, such as absolute absence of morphological expression, in addition to specific theory-internal interpretations of what counts as null. Thus, it is also important to consider the different ways in which something can be morphologically silent. Finally, with respect to the third side of the debate, arguments are made for and against zero morphology, notably from the perspectives of falsifiability, acquisition, and psycholinguistics. Of particular impact is the question of which properties a theory should have in order to block the possibility that zero morphology exists, and conversely the properties that theories that accept zero morphology associate to null morphemes. An important ingredient in this debate has to do with two empirical domains: zero derivation and paradigmatic uniformity. Ultimately, the plausibility that zero morphemes exist or not depends on the success at accounting for these two empirical patterns in a better way than theories that ban zero morphology.

scholarly journals Managing the Oocyte Meiotic Arrest—Lessons from Frogs and Jellyfish

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1150 ◽  
Author(s):  
Catherine Jessus ◽  
Catriona Munro ◽  
Evelyn Houliston
Keyword(s):  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Polar Body ◽  
Model Organisms ◽  
Oocyte Growth ◽  
M Phase ◽  
History Of ◽  
Enormous Variation ◽  
Polar Body Formation ◽  
Reliable Mechanism

During oocyte development, meiosis arrests in prophase of the first division for a remarkably prolonged period firstly during oocyte growth, and then when awaiting the appropriate hormonal signals for egg release. This prophase arrest is finally unlocked when locally produced maturation initiation hormones (MIHs) trigger entry into M-phase. Here, we assess the current knowledge of the successive cellular and molecular mechanisms responsible for keeping meiotic progression on hold. We focus on two model organisms, the amphibian Xenopus laevis, and the hydrozoan jellyfish Clytia hemisphaerica. Conserved mechanisms govern the initial meiotic programme of the oocyte prior to oocyte growth and also, much later, the onset of mitotic divisions, via activation of two key kinase systems: Cdk1-Cyclin B/Gwl (MPF) for M-phase activation and Mos-MAPkinase to orchestrate polar body formation and cytostatic (CSF) arrest. In contrast, maintenance of the prophase state of the fully-grown oocyte is assured by highly specific mechanisms, reflecting enormous variation between species in MIHs, MIH receptors and their immediate downstream signalling response. Convergence of multiple signalling pathway components to promote MPF activation in some oocytes, including Xenopus, is likely a heritage of the complex evolutionary history of spawning regulation, but also helps ensure a robust and reliable mechanism for gamete production.

Thèmes d'inquiétudes et tendance à s'inquiéter chez les aînés

1998 ◽  
Vol 17 (4) ◽  
pp. 361-371 ◽  
Author(s):  
Céline Doucet ◽  
Robert Ladouceur ◽  
Mark H. Freeston ◽  
Michel J. Dugas
Keyword(s):  
Older Adults ◽  
Current Knowledge ◽  
The Elderly ◽  
The Third ◽  
Penn State Worry Questionnaire ◽  
Penn State ◽  
State Worry ◽  
Future Work ◽  
Anxiety Questionnaire ◽  
Group 1

ABSTRACTThe present study examines worry themes and the tendency to worry in older adults. The sample, which is made up of 162 participants, is divided into three groups. The first group includes 47 participants aged from 55 to 64 years old (the youngest subjects). The second group consists of 56 participants aged from 65 to 74 years old. Finally, the third group includes 59 participants who are 75 years old or older (the oldest subjects). Participants completed the Worry and Anxiety Questionnaire, the Worry Domains Questionnaire for Older Adults and the Penn State Worry Questionnaire. For all subjects combined, the most frequently reported worry theme was health, followed by relationships with family and friends. The results show that participants in group 1 (the youngest subjects) worry more about their future, work and finances than those in the other two groups. The results also show that participants in the first two groups have a greater tendency to worry and report a greater number of worries than those in the third group (the oldest subjects). The study's findings are discussed in light of current knowledge of worry among the elderly.

The Role of Bacterial Enzymes in Inducing Inflammation in the Middle Ear Cavity

1979 ◽  
Vol 87 (6) ◽  
pp. 859-870 ◽  
Author(s):  
Seth H. Lowell ◽  
S. K. Juhn
Keyword(s):  
Otitis Media ◽  
Middle Ear ◽  
Bacterial Infections ◽  
Current Knowledge ◽  
Acute Otitis Media ◽  
Bacterial Enzymes ◽  
Infectious Process ◽  
The Third ◽  
Host Tissues

Current knowledge of the pathophysiology of bacterial infections is elementary. The initial events leading to the invasion of host tissues are a matter of conjecture for many bacterial organisms. This is particularly true for pneumococci, the most frequent causative organisms of acute otitis media. Bacterial enzymes may account for the initial disruption of host tissues, and this study explored their role in the infectious process. As a first step, pneumococcal cultures were analyzed, and significant levels of the enzymes lipase and hyaluronidase were demonstrated. Secondly, the presence of these enzymes in middle ear effusions was explored in an animal model of acute otitis media. The enzymes reached peak levels at seven days. The third and most important portion of the study examined the significance of these enzymes in producing inflammation and alterations in the middle ear cavity of normal experimental animals. This portion was a histologic comparison of temporal bone specimens and demonstrated that marked acute and chronic changes can be induced by placing solutions of these enzymes in the middle ear cavity. This study concludes that bacterial enzymes play an important role in the induction of acute otitis media.

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