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Results for “Intranuclear Space”

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At least 145 records · Page 8Linked to original sources

PubMed1997

Abnormal intracellular and extracellular distribution of basement membrane material in papillary carcinoma and hyalinizing trabecular tumors of the thyroid: implication for deregulation of secretory pathways.

Papillary carcinoma (PC) and hyalinizing trabecular tumors (HTT) of the thyroid share several morphological features, including the presence of nuclear pseudoinclusions (NPI). One of the distinct characteristics of HTT is its hyalinizing stroma, which contains abundant basement membrane (BM) material. We investigated the distribution of BM material in PC and HTT. Fifteen cases of PC and nine cases of HTT were analyzed immunohistochemically with monoclonal antibodies for type IV collagen and laminin. Three stromal staining patterns were observed: (1) linear staining along the epithelium lining papillae, between trabeculae, and around follicles; (2) focal absence of staining; (3) lumpy or diffuse stromal staining. Although the latter was more commonly seen in HTT, all three patterns were present in both tumor types. More interestingly, we observed two hitherto undescribed intracellular staining patterns in both tumor types: intracytoplasmic dotlike staining and staining of NPI. Electron microscopy was performed in three cases of PC. Dilated cisternae of endoplasmic reticulum containing dense amorphous material resembling BM were observed in the cytoplasm in one case and in the NPI in another. These findings suggest the presence of a common pathway for the abnormal production of BM in both PC and HTT. Two mechanisms that may account for the abnormal intracellular detection of BM materials are proposed: (1) intracellular invagination/phagocytosis of extracellular matrix by the tumor cells; (2) abnormal production or alteration in secretory pathway in tumor cells resulting in intracellular accumulation and intranuclear invagination. The combination of immunohistochemical and electron microscopic findings favors the latter. The similar patterns of BM deposition shared by PC and HTT further support the hypothesis that PC and HTT are related to each other.

Basement Membrane↗

PubMed1984

Nuclear and cytoplasmic inclusion bodies in pinealocytes of the cotton rat, Sigmodon bispidus: an electron microscopic study.

Electron microscopic observations on pinealocytes of cotton rats (Sigmodon bispidus) killed in October revealed the presence of cytoplasmic inclusion bodies (CIBs) and two kinds of nuclear inclusions--coiled bodies and granular inclusion bodies. These inclusions were usually not bounded by a membrane. CIBs showed round or irregular profiles and consisted of granular and filamentous materials of moderate electron opacity intermingled with electron-lucent areas. Nuclear granular inclusions appeared as homogeneous or heterogeneous granules of variable electron opacity, which usually exhibited round profiles of variable diameters and consisted of granular and filamentous elements. Electron-opaque granules were observed in perinuclear spaces, dilated cisternae of rough endoplasmic reticulum, as well as in the central portion of CIBs. In CIBs containing granules, the peripheral region was composed of the moderately electron-opaque substance seen in usual CIBs, while the central core was occupied by a granular and filamentous substance and an intervening electron-lucent matrix. Since an electron-opaque granular substance in nuclei, perinuclear spaces, cisternae of rough endoplasmic reticulum, and the central portion of CIBs may occur concomitantly, the granules seen in these sites may be related. Coiled bodies were round in profile and were composed of electron-opaque strands consisting of granular and filamentous elements and intervening material of low electron opacity. This structure, frequently located in close proximity to the nuclear granular inclusions, may play a role in the formation of the intranuclear granules in cotton rat pinealocytes.

Animals↗

PubMed1997

Ultrastructural pathology and cytochemical investigations of L-2-chloropropionic acid-induced neurointoxication of the rat cerebellum.

The objectives of the studies described were to assess the ultrastructural neuropathology, blood-brain barrier (BBB) integrity and calcium status of the cerebellum of rats following a single dose of 750 mg.kg-1 L-2-chloropropionic acid (L-2-CPA). The first indications of intoxication appeared at 36 h when condensation of many granule cells associated with Purkinje cell degeneration and marked astroglial swelling were observed. Some electron-lucent granule cells were also noted lying amongst these condensed forms. Condensed granule cells had swollen, electron-lucent mitochondria, dilated Golgi apparatus and nuclear crenation. Occasionally, areas of the granule cell necrosis were also present at this time. Granule cell condensation probably represents a preliminary and irreversible stage in an excitotoxic process that leads to necrosis. At 48 and 72 h, most granule cells were necrotic, and occasionally, extravasation of both erythrocytes and leucocytes into the expanded extravascular space was observed. Evaluation of the BBB by ultrastructural cytochemical visualisation of horseradish peroxidase injected i.v. 2 min before killing by perfusion fixation showed substantial leakage. At 36 h post-dose, ultrastructural calcium localisation using oxalate/pyroantimonate precipitation demonstrated a substantial increase in calcium pyroantimonate precipitate in mitochondria and other membranous cytoplasmic organelles (especially the Golgi apparatus) in condensed granule cells, but with little in their nuclei. However, their immediate neighbours (of ostensibly normal ultrastructural appearances) contained greater amounts of intranuclear precipitate. Swollen astroglial cells (especially the Bergmann glia) contained considerable quantities of precipitate. A possible excitotoxic mechanism via L-2-CPA-induced NMDA receptor agonism leading to overwhelming calcium influx and disruption of cellular calcium homeostasis is proposed.

Animals↗

PubMed2000

Primary envelopment of pseudorabies virus at the nuclear membrane requires the UL34 gene product.

Primary envelopment of several herpesviruses has been shown to occur by budding of intranuclear capsids through the inner nuclear membrane. By subsequent fusion of the primary envelope with the outer nuclear membrane, capsids are released into the cytoplasm and gain their final envelope by budding into vesicles in the trans-Golgi area. We show here that the product of the UL34 gene of pseudorabies virus, an alphaherpesvirus of swine, is localized in transfected and infected cells in the nuclear membrane. It is also detected in the envelope of virions in the perinuclear space but is undetectable in intracytoplasmic and extracellular enveloped virus particles. Conversely, the tegument protein UL49 is present in mature virus particles and absent from perinuclear virions. In the absence of the UL34 protein, acquisition of the primary envelope is blocked and neither virus particles in the perinuclear space nor intracytoplasmic capsids or virions are observed. However, light particles which label with the anti-UL49 serum are formed in the cytoplasm. We conclude that the UL34 protein is required for primary envelopment, that the primary envelope is biochemically different from the final envelope in that it contains the UL34 protein, and that perinuclear virions lack the tegument protein UL49, which is present in mature virions. Thus, we provide additional evidence for a two-step envelopment process in herpesviruses.

Animals↗

PubMed1992

Thyroid hormone alters in vitro DNA binding of monomers and dimers of thyroid hormone receptors.

T3 binds to intranuclear thyroid hormone receptors (TRs) on target DNA elements and exerts profound influences on gene expression by mechanisms not yet characterized. We used gel shift assays and cross-linking experiments to demonstrate that T3 greatly induced the monomeric binding of the hTR beta produced in Escherichia coli to DNA. T3 also increased the gel mobility of these monomer-DNA complexes suggesting they undergo a ligand-induced conformational change. This effect did not depend on the orientation and spacing of the half-site motifs within the DNA structure. In contrast, T3 had diverse effects on the dimeric interaction. T3 increased the dimeric interaction to the palindrome GGTCA.TGACC (an effect lost by spacing the half-sites with 3 base pairs) and decreased the dimeric interaction to the inverted palindrome containing the TGACC.GGTCA motif. Scatchard analyses indicated that the T3 enhancement on binding was due to an increase in the number of TR with high affinity DNA-binding activity and not by increasing the affinity of TR that could bind to DNA. The effects of various T3 analogs were directly related to their affinities for the TR. These ligand effects on in vitro TR-DNA binding may reflect mechanisms by which T3 regulates transcription in vivo.

Animals↗

PubMed1988

Chromatin and nuclear envelope of freeze-fractured, neuronal interphase nuclei, resolved by scanning electron microscopy.

High-resolution scanning electron microscopy (SEM) has previously been used to study intracellular detail, including chromatin. It has, however, been commonly carried out either on cellular subfractions or following extraction methods to visualize detail. In the work presented here, intracellular detail of neurons of the dorsal root was visualized in situ by viewing freeze-fracture faces obtained after hypotonic expansion. This procedure permits the detailed resolution, by SEM, of juxtanuclear and intranuclear detail to a degree impossible without hypotonic dispersal. In agreement with work previously reported, nuclear chromatin of these interphase cells presents largely as 30-nm fibers, with a next higher hierarchical structure imparted by swelling in magnesium chloride. Detailed analyses showed that particles as small as 10-nm nucleosomes comprising the 30-nm chromatin fiber could be resolved, with "end-on" views of such fibers showing 5 nucleosomes per helical turn of the fiber. Chromatin fibers positioned subjacent to nuclear pores, or associated with "nuclear spaces" communicating with nuclear pores, were frequently found to be resolved as clusters, in an apparently more decondensed conformation, rather than tightly coiled into the 30-nm fiber. In addition, details of the nuclear envelope, including nuclear pores and perinuclear filaments as well as membranes of the endoplasmic reticulum, decorated with ribosomes, were clearly resolved.

Animals↗

PubMedDate not supplied

Estrogen receptor in the larynx of the aged baboon (Papio cynocephalus).

Using autoradiographic techniques, tritiated estrogen-receptor complex intranuclear labeling was identified in certain laryngeal tissues of four aged female baboons; no complex labeling was found in the control animal. Three significant findings were felt to be derived from this study. One, surface epithelium of the larynx had essentially no estrogen-receptor activity. Two, all tissues of mesenchymal origin, especially lamina propria, muscle, dense connective tissue, and fat had consistently high levels of nuclear localization of the labeled estrogen. The binding affinity seemed to be the highest at the anterior commissure and the immediate anterior subglottic space. Three, there was a high level of receptor binding in laryngeal cartilage and perichondrium. Since the activated hormone-receptor complex modulates gene expression to alter the amount of mRNA, sex steroids have a direct regulatory effect upon the target cell and, perhaps through an induction process, can exert an indirect effect upon adjacent tissues. It is postulated that since the larynx is a sexually dimorphic organ, the sex steroids and their receptors may play a role in altered phonation during aging and possibly in the development of laryngeal neoplasms and other diseases. Therefore, hormonal manipulation may play a future role in the therapy of laryngeal diseases. This study represents the first demonstration of estrogen receptors by specific anatomic location in the primate larynx with significant localization in the mesenchymal tissues but not in the epithelial tissues.

Adipose Tissue↗

PubMed1999

The intranuclear movement of Balbiani ring premessenger ribonucleoprotein particles.

Specific premessenger ribonucleoprotein (pre-mRNP) particles, the Balbiani ring (BR) granules in the salivary glands of the dipteran Chironomus tentans, can be visualized in the electron microscope when they assemble on the genes, move through nucleoplasm, and bind to and translocate through the nuclear pores. As shown by BrUTP labeling and immunoelectron microscopy, newly synthesized BR RNP particles, released from the BR genes, appear early in all nucleoplasmic regions of the cell nucleus and they saturate the nucleoplasmic pool of BR particles after 2 h of labelling. It is concluded that within the nucleus the BR particles move randomly. Furthermore, estimates of minimum diffusion coefficients for the BR particles are compatible with the view that the particles diffuse freely in the interchromosomal space, although it is not excluded that the random movement could be slightly retarded. Once the particles get bound to the nuclear pore complexes, they seem committed to translocation through the nuclear pores.

Animals↗

PubMed1978

Brain extracellular potassium and general anaesthetics.

General anaesthetic agents (halothane, trichlorethylene, methohexital, pentobarbital, and alphaxalone--alphadolone) depress the extracellular accumulations (deltaEk) and associated focal potentials (deltaV) which are evoked in the cuneate nucleus by tetanic stimulation of peripheral nerves. Depressions of deltaV are significantly greater than those of deltaEk; at the same time there is a dissociation of the relation between deltaV and deltaEk. There are no detectable changes in the resting levels of K+ or the small voltage shifts evoked by low-frequency intranuclear stimulation with a microlectrode. When anaesthesia produces severe hypotension, augmentations of [K+]0 occur which can be attributed to depression of electrogenic Na--K pumping. A possible explanation of the reduction in K+ release resulting from afferent fibre activity would be failure of conduction caused by membrane stabilization or hyperpolarization.

Anesthetics↗

PubMed1973

Unusual intranuclear tubular structures associated with the maturation of Herpesvirus saimiri in monkey kidney cell cultures.

Unusual intranuclear tubules have been observed in cultures of both African green monkey and owl monkey kidney cells infected with Herpesvirus saimiri; the material was studied in thin sections with the electron microscope. The tubules were seen in about 10% of virus-containing cells at the stage when the virus matured by budding at the nuclear membrane, measured 160-180 nm in diameter and up to 3.6 μm in length, were bounded by an outer "membrane" and contained beneath this an electron dense repeating structure arranged either as a coil or a series of evenly spaced rings. The morphology and significance of the tubules are discussed.

Animals↗

PubMed1997

Presence of zinc and calcium permeant channels in the inner membrane of the nuclear envelope.

The nuclear envelope possesses specific ion channels that regulate the ionic traffic between the cytoplasm or the perinuclear space and the nucleoplasm. Using the patch-clamp technique to isolated rat nuclei exhibiting only the inner membrane of the nuclear envelope, we report the existence of calcium and zinc permeant channels. These channels displayed similar characteristics (conductance : 8 and 11 pS respectively, open time constant (3.5 ms and 3.7 ms) and close time constant (5.1 ms and 4.8 ms)) and were insensitive to different types of calcium channels blockers and to calcium concentration in the bathing solution. The exact role of these channels remains to define, but they may contribute to the regulation of intranuclear Ca++ or Zn++ dependent processes as important as cell proliferation or programmed cell death. Moreover, this work demonstrates that our nuclei preparation provides a way to study the inner membrane of the nuclear envelope.

Animals↗

PubMed2005

Live-cell imaging of rhabdovirus-induced morphological changes in plant nuclear membranes.

Potato yellow dwarf virus (PYDV) and Sonchus yellow net virus (SYNV) belong to the genus Nucleorhabdovirus. These viruses replicate in nuclei of infected cells and mature virions accumulate in the perinuclear space after budding through the inner nuclear membrane. Infection of transgenic Nicotiana benthamiana 16c plants (which constitutively express green fluorescent protein (GFP) targeted to endomembranes) with PYDV or SYNV resulted in virus-specific patterns of accumulation of both GFP and membranes within nuclei. Using immunolocalization and a lipophilic fluorescent dye, we show that the sites of the relocalized membranes were coincident with foci of accumulation of the SYNV nucleocapsid protein. In contrast to the effects of PYDV and SYNV, inoculation of 16c plants with plus-strand RNA viruses did not result in accumulation of intranuclear GFP. Instead, such infections resulted in accumulation of GFP around nuclei, in a manner consistent with proliferation of the endoplasmic reticulum. We propose that the relocalization of GFP in 16c plants can be used to study sites of rhabdovirus accumulation in live cells. This study is the first to use live-cell imaging to characterize the effects of rhabdoviruses on plant nuclear membranes.

Green Fluorescent Proteins↗

PubMed1975

Electron microscopic findings of cells with inclusion bodies in experimental hemorrhagic enteritis of turkeys.

The spleen, liver, bone marrow and intestines of two turkeys in which hemorrhagic enteritis of turkeys was experimentally reproduced were examined electron-microscopically. Intranuclear inclusion bodies as described in a previous report were found in all the tissues examined. These occupied most of the area in affected nuclei and were composed of viral particles with morphological characteristics of an adenovirus. The cells with the inclusions were divided into two types of cells, immature and reticular cells. There was some variety in the stage of differentiation of the former cells. As the viral particles developed the cells degenerated and disintegrated. A few particles had been released into the cytoplasm of the degenerated cells but no particles were present in intercellular spaces.

Adenoviridae↗

PubMed1976

Canine herpes-induced retinal dysplasia and associated ocular anomalies.

Thirty-eight newborn Beagle puppies from eight litters of a specific pathogen-free colony maintained in isolation were inoculated with canine herpesvirus. Pups were killed between one and 30 days after inoculation. Histopathologic studies were carried out on the eyes and other tissues in conjunction with fluorescent antibody and viral isolation studies. Evidence of ocular inflammation manifested by panuveitis with the presence of intranuclear inclusion bodies was usually seen by the fourth day after infection. Eyes with severe inflammation showed peripheral anterior synechiae, cataract, and keratitis. The presence of the virus was confirmed by viral isolation from ocular tissues and fluorescent antibody studies. Developmental anomalies included retinal dysplasia with fold and tube formation of the neural retina, retardation of retinal maturation, and areas of necrosis and reorganization were seen. The retinal pigment epithelium showed initially patchy depigmentation and vacuolization and, subsequently, folding hypertrophy and duplication as well as areas of widespread atrophy and patchy loss. In some animals ectopic retina was found within cystic spaces of the optic nerve. These experiments confirm the ability of canine herpes infection in neonatal pups to produce severe ocular inflammation with subsequent retinal dysplasia and associated ocular anomalies.

Animals↗

PubMed2000

Abnormal synaptic plasticity and impaired spatial cognition in mice transgenic for exon 1 of the human Huntington's disease mutation.

Huntington's disease (HD) is an autosomal dominant progressive and fatal neurodegenerative brain disorder caused by an expanded CAG/polyglutamine repeat in the coding region of the gene. Presymptomatic Huntington's disease patients often exhibit cognitive deficits before the onset of classical symptoms. To investigate the possibility that changes in synaptic plasticity might underlie cognitive impairment in HD, we examined hippocampal synaptic plasticity and spatial cognition in a transgenic mouse (R6/2 line) expressing exon 1 of the human Huntington's disease gene containing an expanded CAG repeat. This mouse exhibits a progressive and fatal neurological phenotype that resembles Huntington's disease. We report that R6/2 mice show marked alterations in synaptic plasticity at both CA1 and dentate granule cell synapses, and impaired spatial cognitive performance in the Morris water maze. The changes in hippocampal plasticity were age dependent, appearing at CA1 synapses several weeks before they were observed in the dentate gyrus. Deficits in synaptic plasticity at CA1 synapses occurred before an overt phenotype. This suggests that altered synaptic plasticity contributes to the pre-symptomatic changes in cognition reported in human carriers of the Huntington' disease gene. The temporal and regional changes in synaptic plasticity within the hippocampus mirror the appearance of neuronal intranuclear inclusions, suggesting a relationship between polyglutamine aggregation and dysfunction.

Action Potentials↗

PubMedDate not supplied

[Subthalamic nucleus targeting and spatial variability].

AIM: The effectiveness of anatomic localization of the subthalamic nucleus (EAL) was assessed and the mapping method is described here. The symmetry of contralateral nuclei (SCN) was analyzed on 11 parkinsonian patients submitted to bilateral subthalamotomy with ablative lesioning. PATIENTS AND METHODS: To assess EAL the percentage so much of first trajectory (p1) as the total of trajectories (pt) that hit the target and the rest of subthalamic nucleus average distance (d) was calculated. The anatomic localization error (epsilon) is determined as a difference between first trajectory coordinates with those of medial determined nucleus point, through electrophysiological data as to the statistical significance of this error. SCN is analyzed by contrasting equality hypothesis at the nucleus maximum height alongside a trajectory, average electrophysiological position center and spatial distribution of all intranuclear recordings found in each hemisphere in all patients. RESULTS: The pi, pt and d obtained values were 86.36%, 86.13% and 1.41 +/- 1.01 mm respectively. The epsilon value was greater in anteroposterior direction of 1.11 +/- 0.83 mm without statistical significance. The average number of recorded trajectories for the first procedure was 6.45 and 6 for the second. The asymmetry of contralateral nucleus was not significant. CONCLUSIONS: An indirect method with CT brain images and a new electrophysiological mapping method with a multiunitary recording for first and second nucleus is safe enough and it yields a high effectiveness in anatomofunctional nucleus localization. The nucleus of a same patient are symmetrical. There is little space variability among patient non related to the differences in the intercommissural distance.

Aged↗

PubMed1995

[The formation of the karyosphere in the oogenesis of insects and amphibians].

This review deals with the authors' own and literary data on the ultrastructural and cytochemical organization of insect and amphibian oocyte nuclei, with special attention being paid to the karyosphere and its capsule. The evidence provided is supplemented with data on isolated karyospheres in Rana temporaria oocytes. A conclusion is made that the karyosphere is a complex structure which contains all chromosomes in the limited space of the oocyte nucleus, and that these chromosomes are, as a rule, in the process of inactivation. It is inferred that the karyosphere capsule commonly appears in gigantic oocyte nuclei (more than 100 micron in diameter) containing extrachromosomal DNA. The analogy of capsule organization in different invertebrate and vertebrate species is discussed, in addition to the involvement of presumably homologous nuclear structures (e.g. derivatives of synaptonemal complexes and nuclear envelope) in capsule formation. It is assumed that the karyosphere capsule is a specially organized part of the nuclear matrix. The capsule provides nuclear compartmentalization and chromosome localization in the germinal vesicle. Studies of this sort open up new possibilities to further investigation of intranuclear morphogenesis.

Amphibians↗

PubMed1986

Cutaneous papillomas associated with a herpesvirus-like infection in a herd of captive African elephants.

Proliferative cutaneous lesions developed in a herd of captive African elephants (33 from an animal importer in Texas [group 1], and 63 young elephants collected in Zimbabwe [group 2]). Group-1 elephants were purchased 8 months before the arrival of the group-2 elephants. On arrival, 7 group-1 elephants had raised nodular fibrous growths, located predominantly on their trunks. Lesions were not observed in the group-2 elephants until approximately 3 months after they were acquired. Lesions on group-2 elephants began as small focal proliferative growths that regressed or that progressed into large nodular fibrous growths that were similar in appearance to those seen in the group-1 elephants. Lesions at various stages of development were biopsied and examined. Histologically, early lesions were inverted papillomas, with hyperplastic and hypertrophic epithelial cells containing amphoteric intranuclear inclusions in the lesion center. Older, large, nodular fibrous growths were ulcerated and were composed predominantly of a thickened dermis containing fibroblasts, collagen, and a mixed inflammatory cell infiltrate; inclusions were not observed in adjacent epidermal cells. Using a peroxidase-antiperoxidase technique, we did not detect group-specific papillomavirus antigens. Southern blot hybridization analysis of DNA from lesion specimens did not indicate papillomavirus-specific genomes. Electron-microscopically, inclusions consisted of aggregates of virus particles. The particles had electron-dense and electron-lucent cores and were 95 to 103 nm in diameter. Virions developed envelopes from nuclear membranes. Mature particles were seen within the cytoplasm and filled the intercellular spaces. On the basis of size, location, conformation, and envelopment, the particles most closely resembled those of herpesviruses.

Animals↗