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At least 1,027 records · Page 57Linked to original sources
PubMed2005

The conundrum of skin pores in dermocosmetology.

'Skin pore' is a term used by lay people and in the field of cosmetology. It remains misleading when it is not clearly defined. Indeed, lay people use it with at least 3 different meanings. Basically, invisible pores represent the openings of the sweat gland apparatus. By contrast, the visible pores represent enlarged empty funnel-shaped or cylindrical horny impacted openings of pilosebaceous follicles. This review describes some of the current objective methods used to describe skin pores.

Acne Vulgaris↗
PubMed2005

Evaporated nanostructured Y2O3:Eu thin films.

Europium-doped yttrium oxide (Y2O3:Eu) is a well-known luminescent material that in recent years has been studied in thin-film form. However, to date there has not been a great effort put into altering the nanostructure of these films. A thin-film deposition technique called glancing angle deposition allows for a high degree of control over the nanostructure of the thin film, resulting in thin films with nanostructure geometries ranging from chevron and post to helix. Glancing-angle deposition was used to make europium-doped yttrium oxide thin films with slanted-post nanostructures. Portions of the films were annealed in air at 850 degrees C for 10 hours following deposition. Scanning electron microscopy was used to characterize the nanostructures of the films, while UV laser excitation was used to characterize the photoluminescence properties of the films. The annealed samples exhibited increased photoluminescent responses compared to unannealed samples; however, the porous nanoscale geometry of the films was unaffected. In order to optimize the photoluminescence properties of the films, both the partial pressure of oxygen during film deposition and the level of europium doping in the source material used were varied. Films fabricated from the source material with a greater amount of europium doping had larger photoluminescent responses, while the optimal partial pressure of oxygen during electron-beam evaporation was found to be less than 1.0 x 10(-4) torr.

Europium↗
PubMed2005

Development of a low density colorimetric protein array for cardiac troponin I detection.

This work presented a rapid, inexpensive, reliable, and flexible quantitative immunoassay for cardiac troponin I (cTnI). The assay was based on the concepts of one-step dual monoclonal antibody "sandwich" principle, the low density protein array, the nanogold probe, and the silver enhancement on the gold particles. The capture antibody (IgG1) coated supporting nitrocellulose membrane and the colloidal gold-labeled detection antibody (cAu-IgG2) were prepared before the detection. The detection procedure involved two steps, i.e., immunoreaction and silver amplification. The assay needs only small amounts of serum samples of patients, The whole detection procedure of the assay could be fulfilled within 40 min (much faster than the routine enzyme-linked immunosorbent assay (ELISA) that takes usually at least 3 hours for a turnaround test). The detection results could be easily imaged with a simple flatbed scanner or even observed with the naked eye. The assay showed good specific response to cTnI with very little cross-reactivity to the skeletal isoforms of troponin I (sTnl), cardiac troponin T (cTnT), and myoglobin (Mb). A cut-off value of 0.3 ng/ml was obtained from a reference control group (200 normal serum samples). 588 patients' serum samples were assayed simultaneously by routine ELISA and this colloidal gold method to test the validity of the method. The data were analyzed using the statistical package SPSS version 11.0 (SPSS Inc.) There was no significant difference between these two assays (P = 0.66 > 0.05). The agreement between this method (> or < 0.3 ng/ml) and ELISA was 86%.

Colorimetry↗
PubMed2005

Assemblies of concanavalin A onto carboxymethylcellulose.

The immobilization of Concanavalin A, (Con A), onto flat surfaces formed by ultrathin films of carboxymethylcellulose, CMC, silicon wafers or spin-coated poly(methyl methacrylate), (PMMA), was studied by ellipsometry, contact angle measurements and atomic force microscopy (AFM). The formation of Con A monolayer was only observed onto CMC films. The adsorption constant of Con A onto CMC films was determined as being (2.1+/-0.2) x 10(6) L mol(-1). After assembling Con A onto CMC surfaces, these became more hydrophobic, indicating a molecular orientation of Con A hydrophilic residues to the polysaccharide and Con A hydrophobic residues to the air. The affinity of Con A for hydroxyl rich silicon surfaces or for more hydrophobic PMMA films was very weak, evidencing that nonspecific interactions play a marginal role. For comparison, the immobilization of Con A onto hybrid particles of PMMA/CMC was investigated by means of UV-spectrophotometry. Such particles carry CMC chains attached to the surface, as evidenced by mean zeta potential value of -40 mV. The adsorption constant determined for Con A onto PMMA/CMC particles was one order of magnitude smaller than that found for Con A onto CMC films. This finding indicates that the substrate geometry might influence the molecular arrangement of sugar residues on the surface, consequently affecting the sugar-Con A interaction (cluster effect).

Carboxymethylcellulose Sodium↗
PubMed2001

Temporal relationship between cytochrome c release and mitochondrial swelling during UV-induced apoptosis in living HeLa cells.

During apoptosis, cytochrome c is released from mitochondria to the cytosol to activate a caspase cascade, which commits the cell to the death process. It has been proposed that the release of cytochrome c is caused by a swelling of the mitochondrial matrix triggered by the apoptotic stimuli. To test this theory, we measured directly the dynamic re-distribution of green fluorescence protein (GFP)-tagged cytochrome c and morphological change of mitochondria within living HeLa cells during u.v.-induced apoptosis. We observed that mitochondria did not swell when cytochrome c was released from mitochondria to cytosol during apoptosis. Instead, mitochondria swelled to spherical shapes within 10 minutes of cytochrome c release. This finding strongly suggests that cytochrome c release in apoptosis was not caused by mitochondrial swelling. This conclusion was further supported in two separated experiments using an immunostaining method and carbonyl cyanide m-chlorophenyl-hydrazone (CCCP) treatment. In addition, we found evidence that cytochrome c was also released before mitochondrial swelling in apoptosis induced by other cell death-inducing treatments, including tumor necrosis factor (TNF) and actinomycin D.

Amino Acid Chloromethyl Ketones↗
PubMedDate not supplied

Synthesis and characterization of fluoro-substituted polyaniline.

Poly(2-fluoroaniline) was prepared by both chemical and electrochemical polymerization in acidic medium. Characterization of poly(2-fluoroaniline) was accomplished experimentally using ultraviolet-visible, Fourier transform infrared, differential scanning calorimetry, thermal gravimetric analysis, and X-ray diffraction techniques, respectively. Scanning electron microscopy studies revealed globular morphology of chemically synthesized poly(2-fluoroaniline). The cyclic voltammetric studies revealed diffusion-controlled phenomenon in electrochemically synthesized poly(2-fluoroaniline).

Aniline Compounds↗
PubMedDate not supplied

Mutant Hansenula polymorpha strain with constitutive alcohol oxidase and peroxisome biosynthesis.

A mutant of the methylotrophic yeast Hansenula polymorpha with constitutive alcohol oxidase (AOX) and peroxisome biosynthesis was obtained after UV treatment followed by cell plating on a medium containing methanol and 2-deoxy-D-glucose (DOG). DOG-resistant colonies of mutants were insensitive to catabolic repression by glucose and methanol. A selection procedure is described that allows the isolation of a mutant exhibiting a constitutive phenotype of AOX involved in methanol utilization. Furthermore, additional features of the constitutive presence of peroxisomes are demonstrated. 562 DOG-resistant colonies were tested, 24 of them demonstrating constitutive AOX formation. Based on quantitative analysis, one of the strains--DOG-13 was selected and its growth, biochemical and ultrastructural characteristics were examined. Its specific enzyme activity when cultivated on a yeast nitrogen base + 1% glucose (YNB + 1% Glucose) was found to reach 145 nmol x min(-1) x mg(-1) protein (compared to zero of the parent strain) after he 20th hour of cultivation. This was confirmed by fine-structure analysis, showing typical peroxisomes, which number and size increased with the enzyme activity. This study demonstrates a constitutive AOX and peroxisome biosynthesis by the mutant strain H. polymorpha DOG-13 obtained.

Alcohol Oxidoreductases↗
PubMed2003

Novel observation of a circular dichroism band originating from amyloid fibril.

A peptide fragment of a non-amyloid-beta component (NAC(1-13)) was studied by CD and electron microscopy. Typical amyloid fibrils were observed by EM in a solution of NAC(1-13). In addition to the beta-structural CD band in the far-UV region, a novel CD band near 285 nm was observed in a peptide solution of NAC(1-13). Taking the NAC(1-13) to contain neither an aromatic amino acid residue nor cystine into account, the CD band can be attributed to amyloid fibrils of NAC(1-13).

Amino Acid Sequence↗
PubMed1983

Composite laminate veneers with a continuous inorganic phase comprising microporous sintered glass fiber networks.

Veneers were made from sheets consisting of a three-dimensional network of sintered ultrafine glass fibers. The sheets were molded by a vacuum-pressure technique and then impregnated with a liquid resin. Impregnation was performed with a method that enabled the depth of penetration to be monitored. The resin was cured with UV radiation under N2 protection. By the use of TiO2-containing resins the veneer achieved an enamel-like appearance. An in vitro toothbrush dentifrice abrasion test showed a high wear resistance and persisting surface luster. Scanning electron and light microscopy showed fairly smooth and flat light-reflecting glass structures in the surface.

Composite Resins↗
PubMed1996

Modulation of HLA-DR and CD1a expression on human cornea with low-dose UVB irradiation.

PURPOSE: To evaluate the effects of low-dose UVB irradiation of HLA and CD1a expression and the toxic effects of UVB on human corneas. METHODS: 24 pairs of human corneas from 24 donors were studied. One cornea from each pair was randomly irradiated with UVB (100 mJ/cm2) after enucleation. All corneas were then organ-cultured for 2, 7, 14 or 21 days. Endothelium was studied after enucleation and organ culture. Following preservation, corneas were evaluated by means of light microscopy, morphometry and TEM. HLA and CD1a staining was performed using an immuno-alkaline-phosphatase technique. RESULTS: Endothelial cell loss during organ culture averaged 9.1% in the UVB group and 9.2% in the control group (NS). The number of rosette and reformation figures (p = 0.004) and the coefficient of variation (p = 0.014) were higher in the control group. Epithelial sloughing was more accentuated in the UVB group. We observed the same moderate ultrastructural injuries in both groups. In the epithelium, the average number of HLA-DR+ cells per field was 0.12 in the UVB group and 0.42 in the control group (p = 0.035). In the stroma, these figures were respectively 1.04 and 1.34 (p = 0.026). In the epithelium, the average number of CD1a + cells was respectively 0. 025 and 0.078 (p = 0.019). In the preservation mediums, the average percentage of CD1a + cells was 0.07% in the UVB group and 0.27% in the control group (p = 0.014). CONCLUSIONS: Low-dose UVB (100 mJ/cm2) decreases HLA-DR and CD1a expression of organ-cultured human corneas and induces moderate corneal injuries. Low-dose UVB might be useful for preventing allograft rejection.

Antigens, CD1↗
PubMed2005

Development of green fluorescent protein-expressing bacterial strains and evaluation for potential use as positive controls in sample analyses.

Strains of enterohemorrhagic Escherichia coli O157:H7 and Salmonella Typhimurium were engineered to express the gene for a modified green fluorescent protein (GFP) and were evaluated for potential use as positive controls in sample analyses. The strains fluoresced when observed as colonies with a handheld UV lamp or as individual cells under a fluorescent microscope. The strains maintained their fluorescence following growth in three series of transfer experiments including 8 to 11 passages from broth to broth and twice for 15 consecutive transfers from broth onto Trypticase soy agar plates. Cultures also maintained stability in the ability to fluoresce when agar plates were refrigerated (4 degrees C) for up to 12 days. Growth characteristics of the GFP-positive strains were comparable to those of corresponding control strains. The GFP-positive strains were successfully identified using rapid diagnostic methods and were differentiated from their corresponding non-GFP strains by pulsed-field gel electrophoresis but not by repetitive extragenic palindromic PCR. The GFP-positive and the control strains were recovered successfully from individually inoculated food samples (Feta cheese, raw shrimp, cooked shrimp, and cooked crawfish). However, in one Feta cheese sample and one raw shrimp sample inoculated with combined GFP-positive and GFP-negative cultures, colonies of the GFP-positive strains were not observed under UV light; fluorescing cells in one of the inoculated samples (raw shrimp) were revealed by microscopy. In general, the isolates from the inoculated foods were GFP positive by microscopic examination; the pure isolates could also be restreaked onto Trypticase soy agar, and colonies could be visually examined under UV light. Because GFP strains are not known to occur naturally in the environment, the use of the Salmonella GFP-positive strain may offer advantages as a positive control even when distinct and rare serotypes are available. The GFP-positive E. coli O157:H7 strain may also prove beneficial for use as a positive control strain for sample analyses.

Animals↗