Association of man-made mineral fibre exposure and sarcoidlike granulomas.
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It is assumed that sarcoidosis is caused by inhalation of air borne agents in susceptible persons triggering the inflammatory reaction. The association of metallic dust exposure, such as beryllium and aluminium, and sarcoidlike pulmonary disorders is well known. The ability of man-made mineral fibres (MMMF) to cause granulomatous lung disease has not been appreciated until now. Recently, we observed the association of sarcoidlike granulomatous reaction and occupational history of glass fibre exposure. We hypothesized that there might be a relationship between MMMF exposure and the development of sarcoidlike granulomas. Therefore, the records of 50 sarcoidosis patients-who visited our outpatient clinic between 1996 and 1999 were reviewed. This revealed that 14 cases recalled a history of exposure to either glass fibres or rock wool, both MMMF fibres. The available obtained tissue specimens (n = 12) were reviewed. In six cases electron microscopy qualitative analysis of small fragments of the tissue revealed among others silica, aluminium and sometimes titanium. A distinct relation between fibre deposits fibre deposits and granulomas was found. These findings indicate that in susceptible people MMMF exposure might be related to a chronic granulomatous disease similar to chronic beryllium disease. (+info)
Adhesion of cells to surfaces coated with polylysine. Applications to electron microscopy.
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Cells of many kinds adhere firmly to glass or plastic surfaces which have been pretreated with polylysine. The attachment takes place as soon as the cells make contact with the surfaces, and the flattening of the cells against the surfaces is quite rapid. Cells which do not normally adhere to solid surfaces, such as sea urchin eggs, attach as well as cells which normally do so, such as amebas or mammalian cells in culture. The adhesion is interpreted simply as the interaction between the polyanionic cell surfaces and the polycationic layer of adsorbed polylysine. The attachment of cells to the polylysine-treated surfaces can be exploited for a variety of experimental manipulations. In the preparation of samples for scanning or transmission electron microscopy, the living material may first be attached to a polylysine-coated plate or grid, subjected to some experimental treatment (fertilization of an egg, for example), then transferred rapidly to fixative and further passed through processing for observation; each step involves only the transfer of the plate or grid from one container to the next. The cells are not detached. The adhesion of the cell may be so firm that the body of the cell may be sheared away, leaving attached a patch of cell surface, face up, for observation of its inner aspect. For example, one may observe secretory vesicles on the inner face of the surface (3) or may study the association of filaments with the inner surface (Fig. 1). Subcellular structures may attach to the polylysine-coated surfaces. So far, we have found this to be the case for nuclei isolated from sea urchin embryos and for the microtubules of flagella, which are well displayed after the membrane has been disrupted by Triton X-100 (Fig. 2). (+info)
TNF-alpha increases tracheal epithelial asbestos and fiberglass binding via a NF-kappaB-dependent mechanism.
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Tumor necrosis factor (TNF)-alpha is released from alveolar macrophages after phagocytosis of mineral fibers. To determine whether TNF-alpha affects the binding of fibers to epithelial cells, we exposed rat tracheal explants to TNF-alpha or to culture medium alone, followed by a suspension of amosite asbestos or fiberglass (MMVF10). Loosely adherent fibers were removed from the surface with a standardized washing technique, and the number of bound fibers was determined by scanning electron microscopy. Increasing doses of TNF-alpha produced increases in fiber binding. This effect was abolished by an anti-TNF-alpha antibody, the proteasome inhibitor MG-132, and the nuclear factor (NF)-kappaB inhibitor pyrrolidine dithiocarbamate. Gel shift and Western blot analyses confirmed that TNF-alpha activated NF-kappaB and depleted IkappaB in this system and that these effects were prevented by MG-132 and pyrrolidine dithiocarbamate. These observations indicate that TNF-alpha increases epithelial fiber binding by a NF-kappaB-dependent mechanism. They also suggest that mineral particles may cause pathological lesions via an autocrine-like process in which the response evoked by particles, for example, macrophage TNF-alpha production, acts to enhance subsequent interactions of particles with tissue. (+info)
Heat exposure study in the workplace in a glass manufacturing unit in India.
(60/1409)
The heat exposure for working conditions in coastal areas of tropical and subtropical countries like India is a crucial factor in improved qualitative and quantitative production. The hot climate augments the heat exposure close to sources like furnaces. In the present work heat exposure to workers in glass manufacturing units in a coastal area of India has been assessed. The Wet Bulb Globe Temperature (WBGT), the Corrected Effective Temperature (CET) and Mean Radiant Temperature (MRT) were measured. The WBGT values much exceeded ACGIH TLVs. A revision of these standards to suit tropical and subtropical conditions is required. The recommended durations of work and rest have been estimated. (+info)
The relationship between elution time and eluate volume using the Ultra-TechneKow DTE technetium-99m generator.
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OBJECTIVE: The new Ultra-TechneKow Dry Ship Top Elute 99mTc generator (UTK-DTE generator; Mallinckrodt Medical, Inc., St. Louis, MO) was devised to facilitate fractionated elution with an ergonomically designed elution shield. Fractionation is accomplished traditionally by visually observing the eluted volume through 2 layers of leaded glass windows located in a lighted elution shield and generator auxiliary shield. The goal of our study was to use elution time to determine the endpoint for obtaining the required volume of 99mTc-eluate from a UTK-DTE generator. METHODS: After triplicate elution at several predetermined elution times, the initial weight of the evacuated collecting vial was subtracted from the total weight after elution to determine the elution volume. RESULTS: A quadratic relationship was established between the eluate volume (v, mL) and elution time (t, s) (v = 0.3594 + 0.1889 t - 0.0009 t2). This equation is suitable for use with the 10-mL elution vial. This formula may not be accurate for the first elution since the UTK-DTE generator is a dry-column generator when shipped. The following elution times were calculated for some commonly eluted volumes: 2 mL (9 s), 4 mL (22 s), 5 mL (28 s), 7 mL (45 s), and 10 mL (88 s). CONCLUSION: Our calculated elution time method can be used to predict the eluate volume from a UTK-DTE generator. (+info)
Model system for studying colonization and growth of bacteria on a hydroxyapatite surface.
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A model system for the study of bacterial colonization and growth on a hydroxyapatite (HT) surface is described. Hydroxyapatite was crystallized over the surface of porous glass beads. Chemical analysis of the product showed that the ratio of Ca2+/P042- was indistinguishable from that of commercial HT powder. X-ray diffraction analysis supported the conclusion that the product was HT. A system employing [14C]polyethylene glycol, which selectively adsorbs to the glass surface of the beads, was developed to determine the amount of glass surface covered by HT. Over 90% of the glass surface could be covered by our method. The product, HT beads, consisted of approximately 20% (dry weight) HT. The HT beads possess several properties which make them potentially useful for studying microbial adherence, growth, and interactions. These include: (i) chemical similarity to the tooth surface, (ii) large surface area, and (iii) high density. We also describe a method for direct measurement of the microbial mass of cells growing on beads. The method entails immobilizing a sample on a membrane filter (Millipore), staining it with amido black dye, and eluting the dye for spectrophotometric measurement. Streptococcus mutans served as the test organism. For free-growing bacteria the values measured with the filter assay were directly proportional to cell number, with a value of 1 mug of "protein" corresponding to about 1.5 X 10(6) colony-forming units, determined by viable count. For bacteria colonizing the beads, 1 mug of protein corresponded to about 2 X 10(7) colony-forming units on the beads during logarithmic growth. As the culture approached stationary phase, the efficiency of the assay decreased. These data indicate that multiple random samples, taken at a given time, are representative of the entire culture. (+info)
Consumer perception of risk associated with filters contaminated with glass fibers.
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The filters in Eclipse, a new cigarette-like smoking article marketed by R. J. Reynolds Tobacco Company, are contaminated with glass fibers, fragments, and particles. Reported herein are the results of a study in which consumers were questioned about their opinions as to whether exposure to glass fibers in such a filter poses an added health risk beyond that from smoking and whether the manufacturer has an obligation to inform consumers about the glass contamination problem. The study queried 137 adults who were interviewed while waiting at a Division of Motor Vehicles office in Erie County, New York in 1997. All but one person expressed the view that the presence of glass fibers on the filters poses an added health risk beyond that associated with exposure to tobacco smoke alone. Nearly all expressed the position that the cigarette manufacturer has a duty to inform the public about the potential for glass exposure. (+info)
A bead-based method for multiplexed identification and quantitation of DNA sequences using flow cytometry.
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A new multiplexed, bead-based method which utilizes nucleic acid hybridizations on the surface of microscopic polystyrene spheres to identify specific sequences in heterogeneous mixtures of DNA sequences is described. The method consists of three elements: beads (5.6-microm diameter) with oligomer capture probes attached to the surface, three fluorophores for multiplexed detection, and flow cytometry instrumentation. Two fluorophores are impregnated within each bead in varying amounts to create different bead types, each associated with a unique probe. The third fluorophore is a reporter. Following capture of fluorescent cDNA sequences from environmental samples, the beads are analyzed by flow cytometric techniques which yield a signal intensity for each capture probe proportional to the amount of target sequences in the analyte. In this study, a direct hybrid capture assay was developed and evaluated with regard to sequence discrimination and quantitation of abundances. The target sequences (628 to 728 bp in length) were obtained from the 16S/23S intergenic spacer region of microorganisms collected from polluted groundwater at the nuclear waste site in Hanford, Wash. A fluorescence standard consisting of beads with a known number of fluorescent DNA molecules on the surface was developed, and the resolution, sensitivity, and lower detection limit for measuring abundances were determined. The results were compared with those of a DNA microarray using the same sequences. The bead method exhibited far superior sequence discrimination and possesses features which facilitate accurate quantitation. (+info)