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PubMed2002

Diffuse large B-cell lymphoma and its variants.

According to the World Health Organization classification of neoplastic diseases of the hematopoietic and lymphoid tissues, diffuse large B-cell lymphoma comprises about 40% of adult cases of non-Hodgkin s lymphoma. It consists of the following morphological variants: 1) centroblastic (with or without multilobulated nuclei); 2) immunoblastic (>90% of immunoblasts); 3) T cell/histiocytes rich; and 4) anaplastic. Rare morphological variants plasmablastic type, mediastinal (thymic) diffuse large B-cell lymphoma, intravascular, and primary effusion B-cell lymphoma are considered distinct variants of diffuse large B-cell lymphoma due to their unique topographic presentation and clinical behavior, as well as immunophenotypic and genetic characteristics. T-cell/histiocyte-rich B-cell lymphoma is morphologically characterized by up to 25% of large neoplastic B cells and 75-90% of reactive, non-neoplastic T cells. Mediastinal (thymic) diffuse large B-cell lymphoma is considered a subtype of diffuse large B-cell lymphoma arising in the mediastinum, with distinctive morphological, immunohistochemical, genotypic, and clinical features. Mediastinal diffuse large B-cell lymphoma is an aggressive disease with poor outcome, which probably originates from thymic B cells at the terminal stage of differentiation. During the 1997-2001 period, 720 patients were diagnosed with non-Hodgkin s lymphoma in our institution. Out of 101 (14%) patients with diffuse large B-cell lymphoma, 17 had T-cell-rich B-cell lymphoma and their median survival was less than 20 months, with no difference regarding sex, bone marrow involvement, CD30 positivity, or histiocytic component of the tumor. Twenty out of 101 patients had mediastinal B-cell lymphoma and their median survival was 21 months, with sex or degree of necrosis of the involved lymph node having no impact on survival. We studied the frequency of bcl-2 gene rearrangement in fusion with immunoglobulin receptor gene of t(14;18) and found no such event among 20 of our patients with mediastinal diffuse large B-cell lymphoma. Despite extensive efforts and constant progress in our understanding of non-Hodgkin s lymphoma pathogenesis, the diffuse large B-cell lymphoma group remains heterogeneous entity awaiting further pathological and clinical stratification.

Adult↗

PubMed1992

Initial characterization of a pea mutant with light-independent photomorphogenesis.

We have identified a mutant of pea cultivar Alaska that has many of the characteristics normally associated with light-grown seedlings even when grown in complete darkness. We have designated this mutant lip1, for light independent photomorphogenesis. Etiolated wild-type pea seedlings are white to slightly yellow in color and have a distinct morphology characterized by elongated epicotyls and buds containing unexpanded leaves with small, undifferentiated cells. In contrast, mutant seedlings grown under the same conditions are yellow in color and have short epicotyls and expanded leaves showing clear cellular differentiation. Transmission electron microscopy revealed partially developed, agranal plastids in the dark-grown mutant, unlike wild-type seedlings that contain etioplasts with prolamellar bodies. The mutant also exhibits a much shorter lag period for chlorophyll accumulation when etiolated seedlings are transferred from darkness to white light. The dark-grown mutant has 10-fold less spectrally detectable phytochrome, which can be attributed to a 10-fold reduction in the level of the PHYA polypeptide. Cab, Fed1, and RbcS transcripts are present in dark-grown mutant seedlings at levels comparable to those produced in light-grown material. The levels of these transcripts show a normal decrease when green plants grown for 15 days in a light/dark cycle are transferred to continuous darkness. However, transcript levels remain high during dark treatment of seedlings grown for 9 days in continuous light, indicating that the dark adaptation response in this mutant is developmentally plastic. The lip1 mutant has several features in common with the deetiolated Arabidopsis mutants det1, det2, and cop1. However, there are also several important differences, including varying effects on phytochrome levels, organ-specific gene expression, plastid development, and response to dark adaptation.

Cytokinins↗

PubMed1988

Neurosecretory cells with 'synaptoid perikarya' in Helix. A definitive description of secretory release from the somata of endocrine neurones.

Neurosecretory cells in the mollusc Helix have perikarya that show clear signs of adaptation for both the synthesis and the discharge of secretory material. They are characterized morphologically by juxtaposition with the neural lamella. Passage of hormone into the haemocoel is apparently facilitated in many cases by the extreme attenuation of areas of the lamella and perineurium adjacent to the perikarya and by other forms of histological differentiation. Presumptive sites of release are characterized by prominent aggregations of synaptoid vesicles and the discharge of the contents of secretory granules by exocytosis.

Animals↗

PubMed1977

[Morphological alteration and desintegration of dane particles after exposure with "Gigasept". A first methological attempt for the evaluation of the virucidal efficacy of a chemical disinfectant against hepatitisvirus B ( author's transl)].

A test system based on morphological alterations and desintegration of hepatitis virus B (HBV) is presented for the approximative evaluation of the virucidal efficacy of a chemical disinfectant. Dane particles, supposed to be the infectious entity of HBV, were partially purified by a trap and a rate zonal ultracentrifugation from serum samples of a patient with chronic hepatitis undergoing an immune suppressive treatment because of leukemia. "Gigasept" on the basis of succine dialdehyd and formaldehyd served as disinfectant for this investigation. In one experiment partially purified Dane particles were exposed to the action of a 5% solution of "Gigasept" on electron microscopic grids. Morphological alterations resulting in derounding, break up of the outer membrane, spiral uncoiling as well as asymmetric enlargement of the space between the outer membrane and the core of the HBV was observed after 2 mins. After 15 mins, the HBV were diffusely stained with loss of the characteristic substructure and became polygonal. The decrease of the number of the particles was proportional to the length of the contact time with the disinfectant. In a second series equal volumes of a 5% solution of "Gigasept" and of a HBV containing serum were in contact for 2 hours, with consecutive purification and morphological characterization of the HBV. The sedimentation of the HBs antigenicity differed from the control. A part of the Dane particles was diffusely stained and lost its substructure. Moreover empty particles in the range of the HBc antigen were found. Another part of Dane particles, however, was morphologically unchanged. The relation of intact and non intact particles could possibly serve as parameter for the HBV virucidy.-Thermo inactivation (3 mins, +98 degrees C) of the HBV in a serum was undertaken for comparison.

Aldehydes↗

PubMed1984

Cytologic observations on the effects of metallocene dichlorides on human fibroblasts cultivated in vitro.

The effects of the organometallic cytostatic agents titanocene dichloride (TDC) and vanadocene dichloride (VDC) and of the inorganic cytostatic drug cis-diamminedichloroplatinum(II) (DDP) on the morphologic appearance of human embryonal fibroblasts cultivated as monolayers in vitro were analyzed by light and electron microscopy. All three substances induced similar structural changes which consisted of nuclear as well as cytoplasmic alterations. Many fibroblasts enlarged but the nuclear volume increased more extensively than that of the cytoplasm. The nuclear envelopes underwent invagination so that segmented nuclei were formed and the nucleoli increased in size and density. Within the cytoplasm there was evidence of conspicuous protein synthesis, characterized morphologically by an increase in the size and number of mitochondria, Golgi apparatuses and of cisternae of the rER. The phenomena observed are interpreted as indicating unbalanced cell growth characterized by a selective inhibition of DNA synthesis, coupled with progressive RNA and protein syntheses.

Cell Nucleus↗

PubMed1992

Aerosols characterization in a forested site in Québec, Canada.

Three AERAS low pressure 11 stage cascade impactors with rotatable collecting plates (LPCR) were installed at the Duchesnay forest station near Québec City and four low pressure inertial collectors (LPIC) were installed in the forest. The analysis of the aerosol deposits was performed by static fast atom beam mass spectroscopy (FABMS); SIMS and ESCA analyses were also made. The morphological characterization and the elemental volumetric composition of the aerosols were established by a scanning electron microscope equipped with an X-ray dispersive energy analyser. Micro-weighting of the aluminium substrate before and after the sampling by the AERAS impactor enabled the study of the mass-size-distribution of the aerosols according to their aerodynamic equivalent diameter. Example of the results obtained are presented in relation to air parcels' trajectories. This study has shown that it is possible to characterize the aerosols according to the origin and trajectories of the air mass with which they travel; sources along the tracks have been shown to contribute to the aerosol loading of the air masses.

Aerosols↗

PubMed1998

Quantifying rat pulmonary intravascular mononuclear phagocytes.

Cells of the mononuclear phagocyte system (MPS) protect the host by clearing effete and foreign particulates from the circulation. The current study was designed to identify, quantify, harvest, and provide a partial functional characterization of the systemic host-defense cell located in the pulmonary microvasculature of the rat. Critical colloid doses of test particulates (monastral blue B [MBB] or polystyrene beads) were infused intra-arterially into anesthetized rats so that phagocytically active pulmonary intravascular phagocytes could be identified. Morphologic characterization of in situ phagocytes was performed using electron microscopy. The number of active phagocytes was then determined using tissue samples processed for light microscopy. Finally, sequential perfusion of the pulmonary vasculature with buffer, chelating agent, and collagenase allowed elution and preliminary functional characterization of the pulmonary intravascular mononuclear phagocyte (PIMP). Electron microscopy demonstrated that both mononuclear phagocytes and neutrophils contributed to pulmonary sequestration of circulating particulates. Light microscopy showed that the microvasculature of each alveolus contained 0.50+/-0.19 active mononuclear phagocytes and 0.14+/-0.12 active neutrophils. A chelation/collagenase elution technique was then used to harvest the PIMP. Histologic evaluation of the postperfusion lungs indicated that 80% of the active phagocytes were removed by the technique. In total, the elution fluids contained 2.63+/-1.04 x 10(7) cells, with 1.60+/-0.78 x 10(7), 0.49+/-0.17 x 10(7), and 0.54+/-0.26 x 10(7) of those cells being mononuclear phagocytes, neutrophils, and lymphocytes, respectively. Functionally, the mononuclear phagocyte population exhibited a spectrum of phagocytic activities, with 51.5+/-19.5% of the cells being inactive, 33.9+/-13.4% exhibiting moderate phagocytic activity, and 14.6+/-9.8% demonstrating intensive phagocytic capacity. The current study provides the first quantified demonstration that mononuclear phagocytes are primarily responsible for sequestering blood-borne foreign particulates in the pulmonary circulation of the rat. Approximately 2 x 10(7) PIMP existed in the lungs of 300 gram rats. The functionally heterogeneous mononuclear phagocytes exhibited phagocytic capacities ranging from avidly phagocytic (14.6+/-9.8%) through moderately active (33.9+/-13.4%) to inactive. The lung microvasculature's large pool of inactive mononuclear phagocytes may provide a recruitable mechanism to allow significant increases in clearance of circulating particulates. A resident pool of activatable mononuclear phagocytes might explain previous clinical observations of increased particulate localization in the lung microvasculature of septic patients.

Animals↗

PubMedDate not supplied

Histopathological atlas of renal diseases: Minimal Change disease and focal glomerulosclerosis.

Minimal Change disease and focal segmental glomerulosclerosis are both clinically characterized by presence of Nephrotic Syndrome. The term Minimal Change disease describes a pathology appearance on light microscopy in which there are no definitive changes from normal glomeruli, although the degree of change that is considered significant remains the subject of some controversy. The focal segmental glomerulosclerosis is morphologically characterized by a segmental solidification of the glomerular tuft, due to collapse of the capillary wall, affecting only some glomeruli (focal). It remains unresolved whether Minimal Change disease and focal segmental glomerulosclerosis are different diseases or whether they represent a spectrum of presentation of the same disease process.

Capillaries↗

PubMed2002

Functional anatomy of the basal ganglia.

Four organizational levels of the basal ganglia that could be particularly determinant in terms of functional properties are reviewed: (1) macroscopic anatomy, which is characterized by a dramatic decrease of cerebral tissue volume from the cerebral cortex to the deepest portions of the basal ganglia; (2) connectivity, which consists of both complex loops and a partition into three territories, sensorimotor, associative, and limbic (which process motor, cognitive, and emotional information, respectively); (3) neuronal morphology, characterized by a dramatic numeric and geometric convergence of striatal neurons onto pallidonigral neurons; and (4) dopaminergic innervation of the basal ganglia, which is organized as a dual system that is supposed to have opposite effects on the activity of the system. Current models of the basal ganglia are discussed.

Animals↗

PubMed1979

Morphological differentiation of mechanically dissociated fetal rat brain in aggregating cell cultures.

Rotation-mediated aggregating cell cultures of mechanically dissociated fetal rat brains (15-16 days) were morphologically characterized at 4, 19, 26 and 40 days in vitro. The dissociated cells coalesced into spherical aggregates which increased in diameter from 340 micrometer at 4 days to 430 micrometer at 40 days. Cells within the aggregates developed from an undifferentiated state at 4 days to a population of morphologically mature neurons, astrocytes and oligodendrocytes (26 days in vitro) before degenerating. Synaptic contacts and myelinated axons appeared as the cells differentiated. Neurons tended to occur in clusters that were located in central regions of the aggregates, whereas astrocytes were more concentrated in the periphery. Synapses and myelinated axons were more abundant in central portions of the aggregates. The amount of myelin formed within the aggregates was less than in organotypic cultures or in vivo. These results show that the morphological differentiation of mechanically dissociated aggregates resembles the development of rat CNS in vitro. The ease with which large amounts of aggregates can be prepared provides an in vitro system which can be analyzed biochemically without the use of micro-methods. This advantage is particularly useful for multidisciplinary investigations in developmental neurobiology.

Animals↗

PubMed2006

New mouse oligodendrocyte precursor (mOP) cells for studies on oligodendrocyte maturation and function.

Oligodendrocyte precursor (OP) cells give rise to mature oligodendrocytes (OL), which are necessary for myelination of axons during CNS development and following damage to the myelin sheath that occurs in demyelinating diseases. To facilitate studies designed to understand OP maturation and OL function, we have developed OP cells that can be grown continuously, expanded, and differentiated into mature OLs. Cultures of late passage mOP cells grown in proliferation medium are highly pure early stage oligodendrocyte precursors where > 90% assume a characteristic bipolar morphology. Immunocytochemical analysis using antibodies that recognize progressive stages of OP maturation (A2B5, NG2, GD3 and O4) confirmed that mOP cells have a stable early stage OP cell phenotype. In addition, mOP cells can be induced to differentiate into mature forms of oligodendrocytes in vitro and in vivo, as characterized morphologically by the presence of multiple processes with secondary and tertiary branches, and by immunostaining and quantitative real-time PCR for the mature oligodendrocyte markers MBP, MAG, PLP, and MOBP. Finally, differentiation of mOP cells was accompanied by up-regulation of mRNA encoding Olig2 but not Olig1, which is consistent with previous findings showing that Olig2 is necessary for specification of oligodendrocytes. These new mOP cells should significantly benefit in vitro and in vivo studies on OP maturation and function.

Animals↗

PubMed2002

Design of an injectable system based on bioerodible polyanhydride microspheres for sustained drug delivery.

The fabrication, morphological characterization, and drug release kinetics from microspheres of three bioerodible polyanhydrides, poly[1,6-bis(p-carboxyphenoxy)hexane] (poly(CPH)), poly(sebacic anhydride) (poly(SA)), and the copolymer poly(CPH-co-SA) 50:50 (CPH:SA 50:50) is reported. The fabrication technique yields microspheres with different morphologies for each of the three polymers studied, ranging from very smooth exterior surfaces for poly(CPH) to coarse surface roughness with large pores for poly(SA). Release profiles for the model drug, p-nitroaniline are also different for each polymer. The release profile from poly(CPH) has a large initial burst and shows little additional release after 2 days. The release from poly(SA) is nearly zero-order and lasts for about 8 days. The release profile from CPH:SA 50:50 shows a relatively small burst and then exhibits zero-order release for about I month. The different release profiles are attributed to both polymer erosion rates and drug distribution characteristics of the microspheres. Tailored release profiles of a burst followed by zero-order release are obtained by appropriately combining the microspheres. This technique enables independent modulation of both the burst and the zero-order release rate by varying the number of poly(CPH) and poly(SA) microspheres respectively. Additionally, the zero-order release can be extended from about a week to a month by including CPH:SA 50:50 microspheres.

Anhydrides↗

PubMed2003

The potential effect of short-course high-dose steroid on the maturation and apoptosis of leukemic cells in a child with acute megakaryoblastic leukemia.

High-dose methylprednisolone (HDMP) treatment has been shown to induce differentiation of myeloid leukemic cells in children with acute promyelocytic leukemia and other subtypes (FAB AML M1-M2-M4) of acute myeloblastic leukemia. In the present study, a child with acute megakaryoblastic leukemia (AMKL) was given HDMP (30 mg/kg/day) orally in a single dose for the first 4 days of induction therapy. A marked decrease in peripheral blood blast cells and an increase in platelet count associated with a striking change in bone marrow (BM) morphology was observed following a short-course of HDMP treatment alone. BM cells developed distinct morphology characterized by cytoplasmic blebbing and some appeared as platelet producing micromegakaryocytes. Flow cytometric analysis of the BM cells 4 days after HDMP treatment demonstrated a decrease in the percentage of cells co-expressing CD34 and CD117 antigens and a marked increase in CD42a antigen. These changes in BM morphology and immunophenotype may suggest maturation effect of HDMP on megakaryocytic leukemic cells. In addition ultrastructural analysis of BM cells cultured with methylprednisolone (10(-3) and 10(-6) M) for 24 and 48 h showed numerous apoptotic cells. This was coincident with a significant increase in the percentage of annexin positive cells. These results suggest that HDMP treatment may induce differentiation and apoptosis of leukemic cells in a child with AMKL and it could be a promising agent for remission induction of patients with AMKL.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1994

Inverted pyramidal neurons and interneurons in cat cortical subplate zone are labelled by monoclonal antibody SP1.

During development, the subplate zone of the cat neocortex contains neuronal populations with distinct morphological and neurochemical phenotypes. A subset of those are specifically recognized by a mouse monoclonal antibody termed SUBPLATE-1 (SP1), which was generated against tissue homogenates of kitten cortical white matter. SP1 stains cell bodies and proximal dendrites, but rarely distal dendrites, axonal arbors or spines. In order to characterize morphologically the SP1 immunoreactive subplate cell types, we combined SP1 immunohistochemistry with intracellular iontophoretic injections of Lucifer yellow. The majority of double-labelled neurons were inverted pyramids with a single thicker spine-covered dendrite that descended into the white matter and a tuft of thinner spinous dendrites that ascended from the upper somatic pole, but generally remained confined to the white matter. Other double-labelled neurons were multipolar to bitufted, although often equipped with one thicker descending dendrite. In inverted pyramidal cells, the axons originated from the descending dendrite or, more rarely, from the lower portion of the soma, and descended into the white matter. They formed collaterals recurring toward the grey matter. The presence of dendritic spines on double-labelled pyramidal cells and the axonal arborization patterns were two novel features not revealed previously by SP1 immunohistochemistry alone. The inverted pyramidal morphology was typical for double-labelled neurons located in the subplate zone below the apices of the gyri, whereas those located below the flanks or sulci or deep in the white matter often displayed a bitufted or multipolar spinous morphology. A minority of the double-labelled neurons were multipolar with smooth dendrites and locally branching axons. These results suggest that in the cat subplate zone, a majority of the cells expressing the SP1 antigen are spinous, and we termed the spinous subplate cells 'subplate pyramidal neurons'.

Animals↗

PubMed1992

[Isolation and characterization of mutactimycin-producing mutant].

Natural non-antibiotic producing Streptomyces sp. 1254 was mutagenized by UV irradiation and two active mutants were isolated. Mutant 113 produced novel anthracycline compounds designated mutactimycins. Mutactimycin A was active against the bacteriophage of Bac. subtilis and some viruses in tissue culture. The mutant 2-6 synthesized a basic water-soluble antimicrobial antibiotic. Chemical analysis of the whole cell hydrolysate and the morphological characterization showed that the strain 1254 and its mutant 2-6 were of chemotype I, belonging to the genus of Streptomyces, and the mutant 113 was of chemotype IV without mycolic acid. Co-synthesis test of strain 1254 and a blocked mutant of strain 113 gave the active compounds identical with mutactimycins. Using the actI gene as a probe, the Southern hybridization revealed homology between the actinorhodin polyketide biosynthase gene and the total DNA of the strain 1254. Based on these data it was deduced that Streptomyces sp. 1254 should have a biosynthesis pathway for mutactimycin, but some of its genes might fail in expression and mutagenesis would make the silent gene(s) active.

Antibiotics, Antineoplastic↗

PubMed1997

An inhibitor of the chymotrypsin-like activity of the proteasome (PSI) induces similar morphological changes in various cell lines.

Different established cell lines (SK-v human keratinocytes, B16F10 mouse melanoma, Muntjac fibroblasts, 3T3 mouse fibroblasts, CLV human fibroblasts) as well as primary cultures of mouse fibroblasts and giant cells were treated with N-benzyloxycarbonyl-Ile-Glu(O-t-butyl)-Ala-leucinal (proteasome inhibitor, PSI), a specific inhibitor of the chymotrypsin-like activity of the proteasome. PSI induced well characterized morphological changes in all cell lines studied, including vacuolization and accumulation of perinuclear aggregates, as detected by amido black staining. Together with previous reports on HeLa cells, the present findings support the hypothesis that ubiquitin- and proteasome-dependent proteolysis does not occur randomly in the entire cell, but it is concentrated in a well defined perinuclear region, the proteolytic center.

Animals↗

PubMed1988

Differentiation of muscle, fat, cartilage, and bone from progenitor cells present in a bone-derived clonal cell population: effect of dexamethasone.

RCJ 3.1, a clonally derived cell population isolated from 21-d fetal rat calvaria, expresses the osteoblast-associated characteristics of polygonal morphology, a cAMP response to parathyroid hormone, synthesis of predominantly type I collagen, and the presence of 1,25-dihydroxyvitamin D3-regulated alkaline phosphatase activity. When cultured in the presence of ascorbic acid, sodium beta-glycerophosphate, and the synthetic glucocorticoid dexamethasone, this clone differentiated in a time-dependent manner into four morphologically distinct phenotypes of known mesenchymal origin. Multinucleated muscle cells were observed as early as 9-10 d in culture, lipid-containing adipocytes formed after 12 d, chondrocyte nodules were observed after 16 d, and mineralized bone nodules formed after 21 d in culture. The differentiated cell types were characterized morphologically, histochemically, and immunohistochemically. The formation of adipocytes and chondrocytes was dependent upon the addition of dexamethasone; the muscle and bone phenotypes were also expressed at low frequency in the absence of dexamethasone. The sex steroid hormones progesterone and 17 beta-estradiol had no effect on differentiation in this system, suggesting that the effects of dexamethasone represent effects specific for glucocorticosteroids. Increasing concentrations of dexamethasone (10(-9)-10(-6) M) increased the numbers of myotubes, adipocytes, and chondrocytes; however, when present continuously for 35 d, the lower concentrations appeared to better maintain the muscle and adipocyte phenotypes. Bone nodules were not quantitated because the frequency of bone nodule formation was too low. Single cells obtained by plating RCJ 3.1 cells at limiting dilutions in the presence of dexamethasone, were shown to give rise to subclones that could differentiate into either single or multiple phenotypes. Thus, the data suggest that this clonal cell line contains subpopulations of mesenchymal progenitor cells which can, under the influence of glucocorticoid hormones, differentiate in vitro into four distinct cell types. It is, therefore, a unique cell line which will be of great use in the study of the regulation of mesenchymal stem cell differentiation.

Adipose Tissue↗

PubMed2004

Water-soluble terpolymer-mediated calcium carbonate crystal modification.

The structure of the polymeric substrate plays an important role in the nucleation of calcium carbonate crystals. In this study a synthetic water-soluble poly(acrylamide-co-2-acrylamido-2-methyl-1-propane sodium sufonate-co-n-vinyl pyrrolidone) was found to be a substrate favoring the nucleation of polymorphs of calcium carbonate crystals under specific experimental conditions. Morphological characterization of the polymorphs was done using atomic force microscopy, scanning electron microscopy, energy dispersive spectroscopy, FTIR analysis, and X-ray diffraction. If calcium carbonate is precipitated in the presence of terpolymer, a remarkable increase in nucleation density (number of crystals per unit area) was observed. Stacked crystals of rhombohedral morphology that formed may be due to the presence of sodium sulfonate groups on the terpolymer. However, in the presence of poly-L-aspartic acid, almost all crystals are hollow and have needlelike or plate like morphology was formed. This change in calcium carbonate morphology can be explained by the variation of the polymer conformation, if poly- L-aspartic acid is present.

Journal Article↗