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At least 415 records · Page 23Linked to original sources
PubMed1981

Morphological characterization of a cell population responsible for natural killer activity.

Large granular lymphocytes (LGL) were observed in the peripheral blood, spleen, lung and, to a lesser extent, bone marrow and lymph nodes, but not in the thymus of C3H/HeN mice 8 weeks old. The organ distribution of natural-killer (NK) cytotoxicity closely followed that of LGL. Nude mice had higher LGL percentages and NK activity than normal mice. In addition, the age distribution of LGL from the peripheral blood followed that of NK activity. Employing discontinuous Percoll density gradients the percentage of LGL and the NK cytotoxicity of the low density fractions could be enriched in comparison with the original populations of lymphocytes from peripheral blood and spleen, but not from thymus. These results suggest that, as recently shown for humans and rats, in mice too LGL are associated with NK activity.

Animals↗
PubMedDate not supplied

[Regularities in the formation of the hemomicrocirculation system in embryogenesis and its morphologic characterization in prematurity].

The development of the intraorgan vascular bed in human embryogenesis is brought about by the growth of vascular loops followed by formation of all types of vessels including hemomicrocirculation. Three stages in the formation of hemomicrocirculatory bed can be distinguished: stage I is the integration of vascular loops by means of main and connecting capillaries; stage II-unification of the connecting and main capillaries with true capillaries; stage III consists of formation of arterio-venular, veno-venular and arteriolo-arteriolar anastomoses. Prematurely born children have deficiency of true capillaries in the hemomicrocirculation system, this manifesting by a capillary circulation deficiency and that of transcapillary tissue metabolism. This deficiency is observed in all prematurely born children but its maximum expression is found in the prematurity of degree IV and III.

Embryo, Mammalian↗
PubMed1994

[Morphological characterization of cell lines of human uveal melanoma].

Several cell lines have been derived from an ocular melanoma obtained from an enucleated patient. Three cell types are observed during the time in culture of all the cell lines under study. Two of them have epithelial and spindle shape respectively. A third cell type, having a spheroidal shape, is formed from spindle cells and may be transformed into epithelial cells upon re-seeding. Further experiments showed that the same cell may change of shape following the cycle: spheroidal-->epithelial-->fusiform-->spheroidal. Scanning microscopy shows the coexistence of the three cell shapes in the same culture and the presence of several filaments and processes protruding at the surface of the cells. Transmission electron microscopy shows that the cell lines, in general, contain melanosomes empty or fairly pigmented and several filaments and microtubules. The presence of melanin may be stimulated by seeding of melanoma cells over a "feeder layer" of fibroblasts.

Humans↗
PubMed1993

Morphological characterization of the radiation sensitive cell line, xrs-5.

Morphometric analysis was performed on the radiation sensitive Chinese hamster ovary (CHO) xrs-5 cell line, reverting xrs-5 cells and parental K1 cells. Several ultrastructural parameters (increased nuclear envelope membrane separation, cell and nuclear volume, nuclear to cytoplasmic ratio, and the nuclear surface area per unit volume of the cell) were measured and correlated with radiation sensitivity. A trend in increased cell size and radiosensitivity was observed. However, only the substantially increased nuclear envelope membrane separation in sensitive xrs-5 cells significantly correlated with radiation sensitivity. The maximal nuclear envelope membrane separation in sensitive xrs-5 cells was 270.8 nm. The maximal K1 cell nuclear envelope membrane separation was 134.8 nm, although, on average the K1 cell nuclear envelope membrane separation was 36.8 nm. The reverted xrs-5 cells had a smaller nuclear envelope membrane separation (maximal 83.6 nm), but the measured space did not completely revert to that for K1 cells. Therefore, we conclude that the nuclear envelope membrane separation is correlated with radiation sensitivity of xrs-5 cells, but it cannot be considered as the only defect correlatable with the radiation sensitivity.

Animals↗
PubMed1993

Mammalian cell cultures. Part I: Characterization, morphology and metabolism.

Primary cell cultures are obtained by trypsinization from tissue cultures usually as a monolayer culture. The absence of fetal calf serum will support suspended growth behaviour of spontaneously transformed cells. After several passages the cell line becomes more stable and gives rise to a continuous cell line. Such continuously growing cell lines are a prerequisite for production of recombinant DNA derived proteins. Mammalian cells are 10-100 times larger in diameter than microorganisms. They have no cell wall and express therefore a higher sensitivity to hydrodynamic sheer forces. One of the most stringent problems in mammalian cell culture are "silent" contaminants with mycoplasma which might change cell growth. Mammalian cell cultures show a complex metabolism where regulation of metabolites and catabolites are not fully understood. Glucose is the main carbohydrate source. Also three groups of intercorrelated amino acids are known. Lactate as the primary metabolite of glucose and ammonia as a metabolite of glutamine are expected to be cytotoxic for mammalian cells. Although in some experiments even the addition of ammonia has no significant effect on the viability of hybridoma cells. Adherent cells can be cultivated attached to surfaces such as microcarrier or wire springs. Suspended cells are grown in stirred bioreactors with a comparable technology to fermentation of microorganism. Parameters such as pH, temperature, stirring tip speed and osmolality have to be well controlled in order to obtain high cell viability and cell density.

Animals↗
PubMed1996

Biochemical and morphological characterization of vascular and lymphocytic interleukin-4 receptors.

The distribution of the interleukin (IL)-4 receptor in normal human and common marmoset (Callithrix jacchus) tissues was examined by immunofluorescence and flow cytometry using monoclonal antibodies specific for the human IL-4 receptor to gain further insight into IL-4-mediated inflammatory and immunological events. IL-4 receptor positivity was unequivocally demonstrated on lymphocytes, predominantly T cells, and on blood vessels in many tissues. Vascular IL-4 receptor immunofluorescence consisted of a strong smooth muscle cell positivity and weaker positive staining of capillary and venular endothelial cells. Subnanomolar concentrations of IL-4 induced a genistein-sensitive up-regulation of VCAM-1 in vascular cell cultures. Tumor necrosis factor-alpha induced a genistein-resistant up-regulation of VCAM-1. IL-4 strongly induced expression of the IL-4 receptor on splenocytes (T lymphocytes) but not on vascular smooth muscle or endothelial cell cultures. Receptor cross-linking to [125I]IL-4 revealed a 65- to 75-kDa accessory receptor subunit consistent with a recently cloned IL-13 receptor associated with the IL-4 receptor on both vascular endothelial and smooth muscle cells. The demonstration of a vascular distribution pattern for the IL-4 receptor in addition to expression on lymphocytes suggests that vascular functional alterations, transduced through a unique IL-4 receptor complex (the type II IL-4 receptor), may be of importance during immunological and allergic inflammatory events.

Animals↗
PubMed1975

Dispersed rat parotid acinar cells. I. Morphological and functional characterization.

Morphologically and functionally intact acinar cells have been obtained from the rat parotid gland through enzymatic dispersion with pure collagenase, hyaluronidase, and trypsin as well as mild mechanical forces. Cell yields of 30-50% of the original tissue weight with over 95% acinar cells were accomplished. The cells in suspension assumed a more or less spherical shape but the intracellular polarity of organelle distribution was maintained. The cells in suspension at 37 degrees C maintained stable monovalent cationic composition but lost potassium and gained sodium rapidly upon exposure to ouabain, 10(-5) M. The intracellular amylase concentration and the patterns of secretion of amylase and of synthesis of cyclic AMP by the cells in response to adrenergic stimulation with epinephrine or isoproterenol were comparable to those of the intact gland in situ. In addition, the cells showed good O2 consumption and maintained it constant for periods up to 8 h. These cells could be used as experimental tools for in vitro studies of receptor physiology and biochemistry, cell membrane function, cellular secretory mechanisms, and other parameters of exocrine gland cell physiology.

Amylases↗
PubMed1993

Immunofluorescent identification of endogenous neurotransmitter content in Golgi-impregnated neurons.

A combined Golgi-impregnation/immunocytochemistry procedure was developed to identify the endogenous neurotransmitter content of morphologically characterized neurons. Golgi-impregnated retinal amacrine cells in the lizard Anolis carolinensis were characterized morphologically in thick resin sections. Cells of interest were remounted, resectioned at 1 micron thickness and subjected to a postembedding immunofluorescence procedure to visualize the amino acid neurotransmitters gamma-aminobutyric acid (GABA) or glycine. Double-labeled cells were identified by opaque Golgi deposits in the cytoplasm under bright-field illumination and nuclear immunofluorescence under ultraviolet illumination. Twenty-seven Golgi-impregnated amacrine cells, exhibiting morphological features of GABA-immunoreactive (GABA-IR) cells, were tested for GABA-IR; 21 showed double labeling. Glycine-IR amacrine cells also were identified using the Golgi/immunocytochemistry procedure. This double-labeling procedure allows rapid assessment of endogenous neurotransmitter content in large samples of morphologically characterized neurons.

Animals↗
PubMed2002

Preparation and characterization by morphological analysis of diclofenac/PEG 4000 granules obtained using three different techniques.

The steam granulation is a new wet granulation technique, which involves the use of steam water instead of traditional liquid water as granulation liquid. The aim of this work was to evaluate the possibility of using this new technique to prepare diclofenac-polyethylene glycol 4000 accelerated-release granules. Steam granules were prepared in a laboratory scale high-shear mixer, and their properties were then compared to those of granules, having the same composition, obtained by traditional granulation techniques (wet and melt granulation). The results showed that, selecting the proper process parameters, it was possible to obtain granules using all the three methods; however, the total process time was significantly shorter for steam granulation (30 min) in comparison to traditional wet granulation (70 min), due to the lower amount of used water. The morphological characterization of steam, water and melt granules, performed by scanning electron microscopy (SEM) and image analysis, revealed that steam granules had a more spherical shape and a larger surface area with respect to water and melt ones, suggesting a possible difference in dissolution behavior. Moreover, differential scanning calorimetry (DSC) and X-ray powder diffraction analysis evidenced the transformation of the drug from its originally crystalline form into the amorphous one. Finally, the in vitro dissolution tests showed an increased dissolution rate of the drug from the granules (in particular steam granules) in comparison to pure drug and physical mixture. In conclusion, the results of this study suggested that the steam granulation technique could be considered an interesting alternative to traditional wet granulation to improve the dissolution rate of diclofenac.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2006

Variability and characterization of mycotoxin-producing Fusarium spp isolates by PCR-RFLP analysis of the IGS-rDNA region.

In the present report, a total of 75 Fusarium spp isolates (35 of the Gibberella fujikuroi species complex, 26 of F. oxysporum, 7 of F. graminearum, 5 of F. culmorum, 1 of F. cerealis, and 1 of F. poae) from different hosts were characterized morphologically, physiologically and genetically. Morphological characterization was performed according to macroscopic and microscopic aspects. Physiological characterization was based on their ability to produce fumonisin B1 (FB1), fumonisin B2 (FB2), zearalenone (ZEA) and type B trichothecenes (deoxynivalenol, nivalenol and 3-acetyldeoxynivalenol). FB1, FB2, and ZEA were determined by liquid chromatography and trichothecenes by gas chromatography. Molecular characterization of isolates was carried out using an optimized and simple method for isolation of DNA from filamentous fungi and polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) of the intergenic spacer region (IGS) of the rDNA. The results indicated that G. fujikuroi complex isolates can be divided into low and high fumonisin producers. The haplotypes obtained with HhaI, EcoRI, AluI, PstI and XhoI enzymes provided very characteristic groupings of G. fujikuroi isolates as a function of host type and fumonisin producing capacity. F. graminearum, F. culmorum and F. cerealis isolates were high ZEA and type B trichothecene producers, while F. oxysporum and the G. fujikuroi complex isolates did not show this ability. The haplotypes obtained with CfoI, AluI, HapII, XhoI, EcoRI and PstI enzymes permitted to discern these five Fusarium species and G. fujikuroi complex isolates but the restriction patterns of the IGS region did not show any relationship with the geographic origin of isolates.

DNA, Fungal↗
PubMed2005

Characterization of Fusarium spp. isolates by PCR-RFLP analysis of the intergenic spacer region of the rRNA gene (rDNA).

In the present study, 44 Fusarium spp. isolates (5 Fusarium culmorum, 7 Fusarium graminearum, 1 Fusarium cerealis, 1 Fusarium poae, 26 Fusarium oxysporum, and 4 Gibberella fujikuroi species complex) were characterized morphologically, physiologically and genetically. All except one (Dutch Collection: CBS 620.72) were isolated from different hosts grown in various Spanish localizations. Morphological characterization was made according to macroscopic and microscopic aspects. Physiological characterization was based on their ability to produce zearalenone (ZEA) and type B trichothecenes (deoxynivalenol, nivalenol and 3-acetyldeoxynivalenol). ZEA was determined by liquid chromatography and trichothecenes by gas chromatography. Confirmation was carried out by liquid chromatography-ion trap-mass spectrometry (ZEA) or gas chromatography-mass spectrometry (trichothecenes). Molecular characterization of isolates was performed using an optimized, simple and low-cost method for isolation of DNA from filamentous fungi and polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) of the intergenic spacer region (IGS) of the rRNA gene (rDNA). The results indicate that F. graminearum, F. culmorum and F. cerealis isolates were high ZEA and type B trichothecene producers, the F. poae isolate produced very low level of nivalenol while F. oxysporum and the G. fujikuroi complex isolates did not show this ability. Restriction patterns of the IGS region did not show any relationship with the host, geographic origin of the isolate and mycotoxin-producing capacity. However, the haplotypes obtained with six restriction enzymes (CfoI, AluI, HapII, XhoI, EcoRI and PstI) permitted to discern the six assayed Fusarium species. Therefore, this is a rapid and suitable methodology that allows closely related strains to group and to estimate the genetic relationships between the groups.

Cluster Analysis↗