Immunocytochemical localization of endothelial nitric oxide synthase (e-NOS) and inducible nitric oxide synthase (i-NOS) in rat neurohypophysis after transient cerebral ischemia.

The expression pattern of endothelial and inducible forms of nitric oxide synthase (e-NOS, i-NOS) in rat neurohypophysis after transient ischemia was investigated using post-embedding immunogold method. We demonstrate that ischemia induced an early (10 min) expression of e-NOS not only in endothelium but also in the mast cells. Expression of i-NOS was almost exclusively confined to glial cells (pituicytes) and perivascular macrophages of experimental animals, and peaked at 24 h after ischemia.

Pilot ultrastructural evaluation of human preauricular skin before and after high-energy pulsed carbon dioxide laser treatment.

Background: Carbon dioxide laser resurfacing has recently come into favor for the treatment of photodamaged skin. While the clinical and histologic effects of high-energy short-pulse carbon dioxide lasers on human skin have been investigated, the ultrastructural effects of these lasers have not been documented. Our objective was to study the ultrastructural effects of a high-energy pulsed carbon dioxide laser on photodamaged human skin.

Fluorescent and radiolabeling of polysaccharides: binding and internalization experiments on vascular cells.

Glycosaminoglycans (GAGs) such as heparan sulfates are complex carbohydrate polymers. These structural components of the extracellular matrix are essential for the adhesion, migration, and regulation of cellular growth. To understand the physiological role of GAGs and GAG analogues, a practical approach consists of labeling and detecting them in cell extracts, or analyzing binding domains and their distributions into the cells.

Aminopeptidase B from the rat testis is a bifunctional enzyme structurally related to leukotriene-A4 hydrolase.

An aminopeptidase B (Ap-B) was previously purified to homogeneity from rat testis extracts and characterized. In the present work, by using oligonucleotides selected on the basis of partial amino acid microsequences of pure Ap-B and PCR techniques, the nucleotide sequence of a 2.2-kb cDNA was obtained.

Protracted elevation of endothelin immunoreactivity in hypothalamo-neurohypophysial system after ischemia.

In the present study we investigated the effects of brain ischemia on endothelin expression in the hypothalamo-neurohypophysial system of the rat using the post-embedding immunogold technique for electron microscopy. From 24 hours to six months after ischemia, a relatively high endothelin immunoreactivity was observed in some neurosecretory cells of the supraoptic and paraventricular nuclei as well as in endothelial cells of some microvessels of the hypothalamus and neurohypophysis. The results indicate that ischemia is a potent stimulus for increased production of endothelin.

Localization of endothelin-like immunoreactivity in the hypothalamo-neurohypophysial system of the rat after ischemia.

Endothelin is a very powerful endogenous vasoconstrictor substance produced by endothelial cells. To examine the potential role of endothelin as a neuropeptide, we studied its distribution in the neurosecretory system. Endothelin-like immunoreactivity (EN-IR) has been demonstrated by an immunogold method in the paraventricular and supraoptic nuclear neurons and their terminals in the posterior pituitary of the rat.

Intracellular distribution of ampicillin in murine macrophages infected with Salmonella typhimurium and treated with (3H)ampicillin-loaded nanoparticles.

The intracellular distribution of (3H)ampicillin-loaded polyisohexylcyanoacrylate nanoparticles was studied in murine macrophages (peritoneal cells and the J774 cell line) infected by Salmonella typhimurium C5, using ultrastructural autoradiography. Ampicillin penetration and retention into the cells obviously increased by means of nanoparticles. After short-term (2-4 h) treatment with the nanoparticle formulation, numerous intracellular bacteria were seen to be in the process of destruction.

The PML growth-suppressor has an altered expression in human oncogenesis.

Altered sub-nuclear localisation of the nuclear body-associated PML protein in acute promyelocytic leukaemia, has been proposed to contribute to leukaemogenesis. We have recently shown that PML is a primary target gene of interferons. Here, it is shown that PML has growth suppressive properties and displays an altered expression pattern during human oncogenesis.

Induction of apoptosis by transiently transfected metabolically stable wt p53 in transformed cell lines.

Biochemical and functional properties of wild-type (wt) and mutant p53 were studied under the same cellular environment by transient transfection. Exogenous wt p53 expressed in transformed cell lines was found to be as metabolically stable as mutant p53. Yet only mutant p53 bound to hsp70 whereas wt p53 did not, suggesting that the metabolic stability of p53 does not depend on its ability to form complexes with hsp70.

The t(15;17) translocation alters a nuclear body in a retinoic acid-reversible fashion.

Nuclear bodies (NBs) are ultrastructurally defined granules predominantly found in dividing cells. Here we show that PML, a protein involved in the t(15;17) translocation of acute promyelocytic leukaemia (APL), is specifically bound to a NB. PML and several NB-associated proteins, found as auto-antigens in primary biliary cirrhosis (PBC), are co-localized and co-regulated.

Protein kinase C-like immunoreactivity in gerbil hippocampus after a transient cerebral ischemia.

This study describes immunocytochemical distribution of the protein kinase C (PKC) subspecies: alpha, beta and gamma in the CAI sector of gerbil hippocampus. Immunolabelling was performed with 10 nm gold-antibody complexes against each of the PKC subspecies. The subspecies of PKC were expressed specifically in different populations of hippocampal cells.

Nuclear localization of the Epstein-Barr virus/C3d receptor (CR2) in the human Burkitt B lymphoma cell, Raji.

Epstein-Barr virus/C3d receptor (CR2) is a glycoprotein of mol. wt 140,000 expressed on the surface of Raji cells. We previously isolated phosphorylated CR2 from purified Raji cell nuclei.

Intranuclear distribution of SV40 large T-antigen and transformation-related protein p53 in abortively infected cells.

The intranuclear localization of SV40 T-antigen (T-Ag) and the cellular protein p53 was studied in SV40 abortively infected baby mouse kidney cells using two complementary methods of ultrastructural immunocytochemistry in combination with preferential staining of nuclear RNP components and electron microscope autoradiography. Both proteins were revealed in association with peri- and interchromatin RNP fibrils containing the newly synthesized hnRNA. In addition, T-Ag and p53 remained bound, at least in part, to the residual internal nuclear matrix following nuclease and salt extractions of infected cells.

SV40 large T-antigen and transformation related protein p53 are associated in situ with nuclear RNP structures containing hnRNA of transformed cells.

The localization of SV40 large T-antigen (T-Ag) and the cellular protein p53 in the nuclei of mouse and human SV40-transformed cells and of a methylcholanthrene-transformed mouse cell line, was studied. Their detection by ultrastructural immunocytochemistry with specific monoclonal antibodies employed two complementary methods used in parallel. These consisted of indirect immunoperoxidase labelling carried out before embedment on Triton-permeabilized cells, or indirect immunogold labelling applied to thin sections of cells embedded in Lowicryl K4M.

High resolution autoradiographical detection of RNA in the interchromatin granules of DRB-treated cells.

Isolated rat liver cells were pulse-labelled with tritiated uridine and post-incubated in the presence of an excess of unlabelled uridine and of adenosine analog DRB (5-6-dichloro-1-beta-D-ribofuranosyl benzimidazole). Nuclear radioactivity was detected with high resolution autoradiography. A significant labelling of the interchromatin granules was revealed in these conditions.

Immunocytochemical identification of nuclear structures containing snRNPs in isolated rat liver cells.

Small nuclear ribonucleoproteins (snRNPs) containing U1, U2, U4, U5, and U6 small nuclear RNAs were detected by ultrastructural immunocytochemistry in the nuclei of isolated rat hepatocytes using Fab fragments of anti-Sm and anti-RNP autoantibodies. Their localization was carried out in normal cells and in cells treated with two drugs, the adenosine analog DRB and CdCl2, which alter the number and distribution of nuclear RNP components. It was found that more precise determination of the distribution of these small RNAs could be obtained by using two complementary procedures in parallel rather than either one alone.

Structural organization of rat hepatocyte chromatin as visualized in thin frozen sections selectively stained for DNA.

We studied the structure of rat hepatocyte chromatin in situ using thin frozen sections selectively stained for DNA after aldehyde fixation. Our results indicate that intranucleolar chromatin is arranged into three different organization levels, confirming the observations on Epon-embedded chromatin. These are: completely extended DNA filaments, with a thickness of approximately 3 nm, clustered in loose, roundish agglomerates, very long fibers with a thickness ranging from 15 to 35 nm and compact chromatin clumps.

Ultrastructural cytochemistry of intranuclear dense granules in nasopharyngeal angiofibroma.

Electron-dense round granules (ING) were found in the nuclei of fibroblastic cells of all the tumors examined by us (6 cases) and diagnosed clinically and histologically as nasopharyngeal angiofibroma (NPAF). The ING were consistently associated with this tumor and can be regarded as pathognomonic of NPAF. We studied at the ultrastructural level the composition of these particles using various cytochemical techniques.

Preferential nucleolar localization of Cis-DDP in human fibroblasts.

The use of complex platinum salts (Cis-DDP) in antitumoral therapy is well known. However the mode of action of this salt remains unknown. The present study was performed with human transformed cells in culture (WI-98-VAD), grown in the presence of Cis-DDP.

Effect of quinacrine on nuclear structure and RNA synthesis in cultured rat hepatocytes.

The effects of quinacrine, an antimetabolite which intercalates into DNA, on the ultrastructure of interphase nuclei and on RNA turnover were studied in primary cultures of rat hepatocytes. Procedures included ultrastructural cytochemical staining for ribonucleoprotein and DNA, autoradiography, and measurement of labeled uridine uptake and incorporation. Addition to the culture medium of a nontoxic dose (10 microM for 30 min) reduces the net accumulation of labeled uridine in RNA.

[Monolayer culture of adult mouse hepatic cells secreting albumin and alpha fetoprotein].

Adult mouse liver cells obtained by enzymatic dispersion were maintained in primary cultures for up to 4 weeks. They retained some of the typical morphological and ultrastructural characteristics of hepatocytes. After 2 days of culture, structures similar to bile canaliculi were found and after 6 days clusters of small proliferating cells were noticed in the gaps of the monolayer formed by large well-spread hepatocytes.

[Use of a cryoultramicrotomy method for the purpose of studying chlamydial ultrastructure].

The method of cryoultramicrotomy was adapted for the study of the ultrastructure of HeLa and McCoy cells in monolayer cultures infected with Chlamydia, obligatory intracellular procaryotic parasites, the causative agents of ornithosis (strain Loth) and paratrachoma (strain LB 1). The cryosections were obtained by the fixation of the monolayer with 2.5% glutaraldehyde, by the gradual infiltration of precipitated cells with sucrose (0.