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PubMed1986

Induction of sister chromatid exchanges and chromosome damage by gossypol in bone marrow cells of mice.

The chromosome-damaging potential of gossypol was evaluated by scoring sister chromatid exchanges (SCEs), determining the percentage of pulverized metaphases and the mitotic index in bone marrow cells of mice. Bone marrow cells were collected approximately 21 hours after the intraperitoneal (0,20,40,80, or 160 micrograms/g) and oral (0,40,80, or 160 micrograms/g) administration of gossypol acetic acid. Irrespective of the dosing schedule (single or multiple doses), the vehicle used (physiological saline, corn oil, or 10% aqueous ethanol), and the route of administration, the mean SCE count per cell was significantly higher (P less than 0.05) in gossypol-treated groups than their control counterparts. At 80 and 160 micrograms/g dose levels, the occurrence of metaphase chromosome pulverization was significantly greater, while mitotic index values were markedly lower than those of the corresponding control values. The results suggest that gossypol is a potentially mutagenic and clastogenic agent in murine bone marrow cells.

Animals↗
PubMed1995

Condensation anomalies and exclusion in micronuclei of rearranged chromosomes in human fibroblasts cultured in vitro.

Anomalies of chromatin condensation, such as fragmentation, uncoiling and pulverization, were observed in XP9UV25, a xeroderma pigmentosum fibroblast clone in which a high proportion of cells carried an end-to-end dicentric chromosome, dic (5;16) (p15.2;q24), that gives rise during propagation in culture to a variety of dicentric and monocentric derivatives. The coiling anomaly affected exclusively part of a rearranged chromosome, in particular the region previously involved in breakage events. The heterochromatic 16q region, which is a preferential breakpoint in the formation of dicentric and monocentric derivatives, was consistently the limit of the uncoiled or pulverized regions. This observation suggests that the anomalous chromatin behavior could derive from alteration of a region relevant for the correct condensation of the chromosome. In XP9UV25 the frequency of nuclei with associated micronuclei increased with time in culture, in parallel with that of mitoses with dicentric chromosomes. In situ hybridization with DNA probes specific for chromosomes 5 and 16 revealed hybridization signals in about 40% of micronuclei. Since the frequency of micronuclei is about ten times less than that of dicentrics, it is probable that only the rearranged chromosomes undergoing coiling anomalies are excluded in micronuclei.

Cells, Cultured↗
PubMed1995

Abnormal integrity of the nucleolus associated with cell cycle arrest owing to the temperature-sensitive ubiquitin-activating enzyme E1.

A mouse cell mutant, ts85, containing the temperature-sensitive ubiquitin-activating enzyme was arrested in G2 phase at the non-permissive temperature. In the arrested cells, azure C, a nucleolus-specific stain, revealed a U-shaped or ring-shaped arrangement of nucleolar lobes with an unstained region in the center. Silver staining of the nucleolar organizer region (NOR) and fluorescence in situ hybridization (FISH) with rDNA both gave signals in azure C-positive regions. Electron microscopic examination revealed a cloud of unidentified electron-dense particles (diameter approximately 70 nm) in the azure C-negative center space. When the arrested cells were released into M-phase, we observed the association of NOR-bearing chromosomes with a pulverization-like abnormality. FISH with rDNA and NOR silver staining demonstrated that the pulverization-like abnormality was restricted to NORs. The frequent occurrence of persistent nucleolar material in prophase and prometaphase of the stressed cells after release indicated a delayed dissociation of the nucleolus that brought about the abnormal chromosomes in M-phase. ts85 cells transfected with the mouse E1 cDNA recovered growth at the non-permissive temperature and no longer showed abnormal nucleolar morphology. It seems that the ubiquitin system plays a role in the dissolution of the nucleolus, possibly involving the NOR-bearing chromosomes.

Animals↗
PubMed1995

The first known use of vermillion.

Vermillion has been shown to be useful in preserving human bones from 5000 years ago. Remarkably well-preserved human bones have been found in the dolmenic burial 'La Velilla' in Osorno (Palencia, Spain), carefully covered by pulverized cinnabar (vermillion) which ensured their preservation even in non-favorable climatic conditions. We believe the red powder was deliberately deposited for preservative use because no cinnabar mine is to be found within 160 km, because of the large amount (hundreds of kilograms) used, and because its composition, red mercuric sulphide, is similar to that of preparations used in technical embalming. This finding pushes back the data of the use of mercury ore for preservation by four millennia in South America, and by at least one millennium in the Old World. Chemical and thermal analyses of vermillion in La Velilla have demonstrated its great purity and shown that the cinnabar was pulverized and washed (but not heated), producing a bright red-orange tone.

Archaeology↗
PubMedDate not supplied

Early chromosome condensation without cell fusion. I. Preliminary results with allogeneic and xenogeneic cells.

Early chromatin condensation in interphase cells (G1) of human peripheral blood lymphocytes has been induced without virus or cell fusion by exposure to allogeneic or xenogeneic mitotic cells. The event, although similar in some ways to the phenomenon described as "premature chromosome condensation," "chromosome pulverization," and "prophasing," differs in that it does not require the presence of viruses and cell fusion before mitosis proceeds in the G1 cell. Early chromatin condensation in interphase cells induced by mitotic cells only, consists of chromatids in the early or late G1 phase of the cell cycle that are not pulverized or fragmented at mitosis. Some of the chromosomes are twice as long as the metaphase chromosomes and exhibit natural bands. Almost twice as many of these bands are produced as by trypsin treatment of metaphase chromosomes. The nuclear membrane is intact and nucleoli are present, to which some chromosomes are attached. The DNA content of the precocious chromosomes in G1 is half the amount of the metaphase complement.

Animals↗
PubMed1996

Double minutes in the papillary thyroid cancer cell line PTC-1113A.

The cell line PTC-1113A was established from a metastasizing recurrent papillary thyroid cancer. The cell line was growing as monolayer and showed a complex karyotype with chromosome numbers ranging from 30 to 140/metaphase. A proportion of metaphases contained double minutes and/or pulverized chromosomes. Extrachromosomal DNA seemed to originate from a B-group chromosome. A chromosome 4 painting probe hybridized to extrachromosomal material, representing double minutes (dmin) and possibly minutes. In addition, fluorescence in situ hybridization (FISH) with the chromosome 4 library detected a translocation chromosome and a pulverized chromosome originating from chromosome 4. PTC-1113A is, to our knowledge, the single papillary thyroid cancer cell line demonstrating evidence of gene amplification.

Aged↗
PubMed1987

Cytogenetic effects of vaginally administered gossypol in murine bone marrow cells.

The cytogenetic effects of gossypol were evaluated by determining the frequency of sister chromatid exchanges (SCEs), percentage of pulverized metaphases, mitotic indices and micronuclei in bone marrow cells of mice treated per vaginam. A dose-dependent increase in the frequency of SCEs was observed when gossypol suspended in corn oil was administered at dosages of 10, 20 or 40 micrograms/g. In comparison with controls, incidences of SCEs were significantly higher in mice given 20 and 40 micrograms/g gossypol, whereas the mitotic indices, percentages of pulverized metaphases and the frequency of interphase micronuclei in treated animals were not different from their control counterparts. The SCE data suggest that gossypol has a DNA-damaging potency in murine bone marrow cells.

Administration, Intravaginal↗
PubMed2005

Efficacy of bioabsorbable antibiotic containing bone screw in the prevention of biomaterial-related infection due to Staphylococcus aureus.

Impregnation of antimicrobial agents within biodegradable orthopedic implants provides a possibility for local antimicrobial prophylaxis of biomaterial-related infections. The objective of this study was to evaluate the efficacy of a bioabsorbable ciprofloxacin containing bone screw (Ab-PLGA) in the prevention of biomaterial-related infection due to Staphylococcus aureus in a rabbit model. Animals in Group I (n=8) received a Ab-PLGA screw contaminated with S. aureus, while animals in Group II (n=8) received a stainless steel (SS) screw contaminated with S. aureus. In two negative control groups, the animals received a Ab-PLGA screw (Group III, n=4) or a SS screw (Group IV, n=4) without bacterial contamination. 18F-FDG-PET imaging, performed at 6 weeks, was applied as a novel quantitative in vivo imaging modality of implant-related infection. Infection was verified by swab cultures, direct cultures of the retrieved implant, and quantitative cultures of pulverized bone. The concentrations of ciprofloxacin in serum and local bone tissue were determined by a high performance liquid chromatographic (HPLC) method with fluorescence (FLD) detection. In the group of contaminated Ab-PLGA screws, all cultures were negative. In the group of contaminated SS screws, all cultures of retrieved implants and six cultures out of eight of pulverized bone were positive for inoculated S. aureus. In negative control groups, all cultures were negative except one contaminant (S. cohnii) found in a SS screw culture. Verified infection of contaminated SS screws was collaborated by the increased 18F-FDG-PET uptake (P=0.004 compared with the group of contaminated Ab-PLGA screws). The mean bone tissue concentration of ciprofloxacin varied from 2.54 to 0.83 microg/g bone as a function of distance from the implantation site. The serum concentration of ciprofloxacin remained undetectable and below the resolution of the analytic method (<5.0 ng/ml). This study confirmed the in vivo efficacy of bioabsorbable antibiotic containing bone screw in the prevention of biomaterial-related infection due to S. aureus.

Absorbable Implants↗
PubMed2006

A comparison of the antimicrobial efficacy of NaOCl/Biopure MTAD versus NaOCl/EDTA against Enterococcus faecalis.

The purpose of this investigation was to compare the antimicrobial efficacy of irrigating with 1.3% NaOCl/Biopure MTAD versus irrigation with 5.25% NaOCl/15% EDTA in the apical 5 mm of roots infected with Enterococcus faecalis. Bilaterally matched human teeth were sterilized and inoculated with E. faecalis. After chemomechanical root canal preparation, the root-ends were resected and pulverized in liquid nitrogen to expose E. faecalis in dentinal tubules or other recesses away from the main root canal system. The number of colony forming units (CFU) of E. faecalis per mg was determined from the pulverized root-ends. No significant differences were seen (t = 0.70, p = 0.495) between the number of colony forming units of E. faecalis for teeth irrigated with 5.25% NaOCl/15% EDTA (mean 131 +/- 291 CFU/mg) versus those teeth irrigated with 1.3% NaOCl/Biopure MTAD (mean 187 +/- 237 CFU/mg). This study demonstrated that there is no difference in antimicrobial efficacy for irrigation with 5.25% NaOCl/15% EDTA versus irrigation with 1.3% NaOCl/Biopure MTAD in the apical 5 mm of roots infected with E. faecalis.

Citric Acid↗
PubMed2005

Tests for the evaluation of ammonium attenuation in MSW landfill leachate by adsorption into bentonite in a landfill liner.

Uncontrolled leachate emissions are one of the key factors in the environmental impact of municipal solid waste (MSW) landfills. The concentration of ammonium, given the anaerobic conditions in traditional landfills, can remain significantly high for a very long period of time, as degradation does not take place and volatilisation is not significant (the pH is not high enough to considerably shift the equilibrium towards un-ionised ammonia). Recent years have witnessed a continuous enhancement of landfill technology in order to minimize uncontrolled emissions into the environment; bottom lining systems have been improved and more attention has been devoted to the study of the attenuation of the different chemicals in leachate in case of migration through the mineral barrier. Different natural materials have been considered for use as components of landfill liners in the last years and tested in order to evaluate the performance of the different alternatives. Among those materials, bentonite is often used, coupled with other materials in two different ways: in addition to in situ soil or in geocomposite clay liner (GCL). A lab-scale test was carried out in order to further investigate the influence of bentonite on the attenuation of ammonium in leachate passing through a landfill liner. Two different tests were conducted: a standardized batch test with pulverized bentonite and a batch test with compacted bentonite. The latter was proposed in order to better simulate the real conditions in a landfill liner. The two tests produced values for the partition coefficient K(d) higher than the average measured for other natural materials usually utilized as components of landfill liners. Moreover, the two tests showed similar results, thus providing a further validation of the suitability of the standard batch test with pulverized bentonite. A thorough knowledge of attenuation processes of ammonium in landfill liners is the basis for the application of risk analysis models for the evaluation of the failure of bottom liners or their components.

Adsorption↗
PubMed2005

Water-soluble characteristics of chlorine in char derived from municipal solid wastes.

Chlorine in char derived from municipal solid waste (MSW) was characterized and quantified based on its water solubility: easily water-soluble, hardly water-soluble, and non-water-soluble chlorine. For that, a four-cycle process of water-washing, heating or carbonation were carried out. In order to confirm the characteristics of non-water-soluble chlorine, additional thermal treatment and an alkali-acid washing process were applied to washed char. It was found that a large particle size of char (0.5-1.0 mm) significantly contributed to the amount of non-water-soluble chlorine. Pulverization and HNO3-HF digestion were performed to identify a factor to interfere chlorine release from char with a large particle size. Pulverization was proven ineffective for release of non-water-soluble chlorine, whereas approximately 32% of non-water-soluble chlorine was extracted by HNO3-HF digestion. Therefore, the presence of non-water-soluble chlorine is likely to originate from its chemical property rather than simply from its physical one.

Carbon↗
PubMed1998

In vivo effect on pig chromosomes of high dosage vaccine against classic swine fever.

Hog cholera virus (HCV) can induce chromosome abnormalities in diseased pigs as well as in those vaccinated with attenuated virus vaccine against classic swine fever. An experiment was made using animals from potency and safety control tests of commercial vaccines in Argentina. The different types of chromosomal alterations observed were chromatid and chromosome breaks, chromatid exchanges, polyploid, multiple aberrations cells, and chromosome pulverization. In this study the occurrence of chromosome alterations in pigs receiving either 1 or 10 vaccine doses was evaluated by means of blood sampling at different periods after vaccination. An essay comparing prolificity between treated and non-treated sows was also made. Significant differences in the amount of damaged chromosomes as well as differences in the type of predominant alterations between the two treatments were observed. Aberration frequencies increased from the 5-day postvaccination period reaching the highest value of 4.14% at the 10th, for the one-dose treatment; and highest value of 42.7% including 33.96% of cell with chromosome pulverization which was found in the 7th day interval when applying 10 doses. From then on, the proportion of affected cells dropped until the 20th day interval, which was the last recorded. The prolificity trial did not show any difference between treated and control sows, indicating that chromosome alteration might be limited to lymphocytes. It is concluded that HCV maintains its mutagenic potentiality in the attenuated vaccine, being able to induce chromosomal damage as it does in classic swine fever diseased animals.

Animals↗
PubMed1992

Effect of bleaching agents on inorganic components of human dentin and cementum.

The effect of bleaching agents on the inorganic composition of human dentin and cementum was examined. Intact teeth were crushed, pulverized, and separated to dentin and cementum powders. The pulverized tissues were exposed to treatments with 30% H2O2, 3% H2O2, 2% sodium perborate in 30% H2O2, 2% sodium perborate in 3% H2O2, and 2% sodium perborate in bidistilled water for periods of 15 min and 1, 24, and 72 h. The degree of dissolution and the percentage of inorganic material for both dentin and cementum were measured. Thirty percent H2O2 and 2% sodium perborate in 30% H2O2 treatments significantly increased the solubility of dentin and cementum. The degree of dissolutions and the percentage of inorganic material remaining in the undissolved dentin and cementum increased with time progression. The greatest increase occurred with 30% H2O2 and 2% sodium perborate in 30% H2O2 after 24- and 72-h treatments. It is concluded that 30% hydrogen peroxide treatment may cause alteration in the chemical structure of the dentin and cementum making them more susceptible to degradation.

Borates↗
PubMed2002

Waste plastics as supplemental fuel in the blast furnace process: improving combustion efficiencies.

The possibility of using waste plastics as a source of secondary fuel in a blast furnace has been of recent interest. The success of this process, however, will be critically dependent upon the optimization of operating systems. For instance, the supply of waste plastics must be reliable as well as economically attractive compared with conventional secondary fuels such as heavy oil, natural gas and pulverized coal. In this work, we put special importance on the improvement of the combustibility of waste plastics as a way to enhance energy efficiency in a blast furnace. As experimental variables to approach this target, the effects of plastic particle size, blast temperature, and the level of oxygen enrichment were investigated using a custom-made blast model designed to simulate a real furnace. Lastly, the combustion efficiency of the mixture of waste plastics and pulverized coal was tested. The observations made from these experiments led us to the conclusion that with the increase of both blast temperature and the level of oxygen enrichment, and with a decrease in particle size, the combustibility of waste polyethylene could be improved at a given distance from the tuyere. Also it was found that the efficiency of coal combustion decreased with the addition of plastics; however, the combustion efficiency of mixture could be comparable at a longer distance from the tuyere.

Coal↗
PubMed2004

Preliminary assessment of three new European leaching tests.

Leaching tests are used for characterization purposes and are indispensable for characterization of waste- and building materials. In several countries the use of leaching tests is settled by legislation. Since Europe is becoming a more united community, legislation becomes more and more harmonized as a logical next step in a more European approach towards environmental issues. In this study a comparison is made between three leaching tests, which are being developed in CEN technical committee 292. The percolation test is basically a column filled with granulated material, which is percolated with simulated rainwater for 3 weeks. The amount of water corresponds to 10 times the amount of solid; the eluate is sampled in several fractions. The second test is the pH-stat test in which pulverized material is leached for 24 h at eight different pH-values with the same liquid/solid ratio of 10. The third test reported is the shake test, in which the maximum leachable amount is being investigated at the materials own pH-value. For this purpose pulverized material was used and the total amount, of water had again the same liquid/solid ratio of 10. A comparison was made in exchangeability of produced data. The results of the leaching experiments were comparable within limits of +20 to -43%. Other matters such as running time, information generated about leaching behavior and cost are also discussed. The pH-stat test gives the most information, but is expensive. The percolation test generates detailed information, whereas the shake test is a relatively inexpensive alternative for the percolation test.

Construction Materials↗
PubMed2004

Production and processing of Metarhizium anisopliae var. acridum submerged conidia for locust and grasshopper control.

Currently, mycopesticide development for locust and grasshopper control depends on aerial conidia or submerged spores of entomopathogenic fungi. In our study, the production of submerged conidia of Metarhizium anisopliae var. acridum (IMI 330189) was investigated in a liquid medium containing 3% biomalt and 1% yeast extract (BH-medium). The effects of freeze and spray drying techniques on the quality of submerged conidia were determined. The influence of different additives on the viability of fresh submerged conidia and their suitability for oil flowable concentrate formulation development was assessed. In a BH medium maintained at 180 rev min(-1), at 30 degrees C for 72 h, IMI 330189 produced a green pigmented biomass of submerged conidia whereas in Adámek medium it produced a yellowish biomass of submerged spores. The spore concentration was high in both media; however, the size of the spores produced in the BH medium was significantly lower than those produced in Adámek medium (P < 0.001). Submerged conidia can be effectively dried using either freeze or spray drying techniques. The viability and speed of germination were significantly affected by the drying and pulverizing process (P < 0.001). The initial viability was significantly higher for spray-dried submerged conidia than for freeze-dried spores. Pulverizing of freeze-dried submerged conidia reduced the speed of germination and the viability by 63-95%. Dried submerged conidia can be stored over 45 wk at low temperatures (< 10 degrees) without suffering a significant loss in viability. Furthermore, we have identified carriers that are suitable for oil flowable concentrate formulation development.

Animals↗
PubMed2005

Sorption kinetics of organic contaminants by sandy aquifer and its kerogen isolate.

Long-term sorption behaviors of phenanthrene (Phen) on the Borden sand from 1 min to 365 days and of Phen and 1,2-dichlorobenzene (DCB) on the isolated kerogen from 1 to 120 days were characterized by examining the time dependence of solute phase distribution relationships (PDRs) and compared with the prior reported sorption of tetrachlorobenzene (TeCB) and tetrachloroethene (PCE) on the pulverized and/or acid-treated bulk sand and size fractions. The sorption kinetics for Phen on the bulk sand and its kerogen isolate can well be described by the fractional power kinetics equation (q(e) = kt(b)). The similar rate parameter b for q(e)(t) vs t at 5-7 levels of initial concentrations of Phen on the two sorbents, respectively, ranging from 0.077 to 0.099 and from 0.072 to 0.086, indicates the similar sorption kinetics rate. The modified-Freundlich parameters of TeCB on the pulverized or acid-treated 0.3-mm size fraction match those of Phen on the isolated kerogen, suggesting the same natural organic matter (NOM) property of the two sorbents. As the prior investigation underestimated the Koc value for the TeCB sorption on the acid-treated 0.3-mm size fraction by a factor of 1.76, the estimated time to reach 95% of sorption equilibrium is much longer than the prior estimation (over 10 years vs about 2.5 years). The estimated times to reach 95% of sorption equilibrium at three levels of relative solubility for Phen on the bulk sand and its isolated kerogen are, respectively, longer than one decade, demonstrating the similar diffusion length for Phen on the two sorbents. The observed slow sorption kinetics is related to nanometer-pore diffusion within kerogen matrix. The investigation supplies new clues for explaining the often observed much longer persistence of organic contaminants in soils and sediments than the prediction based on the short-term laboratory experiment.

Adsorption↗
PubMed2005

Phosphine from rocks: mechanically driven phosphate reduction?

Natural rock and mineral samples released trace amounts of phosphine during dissolution in mineral acid. An order of magnitude more phosphine (average 1982 ng PH3 kg rock and maximum 6673 ng PH3/kg rock) is released from pulverized rock samples (basalt, gneiss, granite, clay, quartzitic pebbles, or marble). Phosphine was correlated to hardness and mechanical pulverization energy of the rocks. The yield of PH3 ranged from 0 to 0.01% of the total P content of the dissolved rock. Strong circumstantial evidence was gathered for reduction of phosphate in the rock via mechanochemical or "tribochemical" weathering at quartz and calcite/marble inclusions. Artificial reproduction of this mechanism by rubbing quartz rods coated with apatite-phosphate to the point of visible triboluminescence, led to detection of more than 70 000 ng/kg PH3 in the apatite. This reaction pathway may be considered a mechano-chemical analogue of phosphate reduction from lightning or electrical discharges and may contribute to phosphine production via tectonic forces and processing of rocks.

Geological Phenomena↗