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PubMed2003

Dietary accumulation of perfluorinated acids in juvenile rainbow trout (Oncorhynchus mykiss).

Perfluorinated acids (PFAs) recently have emerged as persistent global contaminants after their detection in wildlife and humans from various geographic locations. The highest concentrations of perfluorooctane sulfonate are characteristically observed in high trophic level organisms, indicating that PFAs may have a significant bioaccumulation potential. To examine this phenomenon quantitatively, we exposed juvenile rainbow trout (Oncorhynchus mykiss) simultaneously to a homologous series of perfluoroalkyl carboxylates and sulfonates for 34 d in the diet, followed by a 41-d depuration period. Carcass and liver concentrations were determined by using liquid chromatography-tandem mass spectrometry, and kinetic rates were calculated to determine compound-specific bioaccumulation parameters. Depuration rate constants ranged from 0.02 to 0.23/d, and decreased as the length of the fluorinated chain increased. Assimilation efficiency was greater than 50% for all test compounds, indicating efficient absorption from food. Bioaccumulation factors (BAFs) ranged from 0.038 to 1.0 and increased with length of the perfluorinated chain; however, BAFs were not statistically greater than 1 for any PFA. Sulfonates bioaccumulated to a greater extent than carboxylates of equivalent perfluoroalkyl chain length, indicating that hydrophobicity is not the sole determinant of PFA accumulation potential and that the acid function must be considered. Dietary exposure will not result in biomagnification of PFAs in juvenile trout, but extrapolation of these bioaccumulation parameters to larger fish and homeothermic organisms should not be performed.

Acids↗

PubMed2003

Toxicokinetics of sediment-sorbed benzo[a]pyrene and hexachlorobiphenyl using the freshwater invertebrates Hyalella azteca, Chironomus tentans, and Lumbriculus variegatus.

This study investigated the effect of long-term sediment aging on the toxicokinetics of benzo[a]pyrene (BaP) and hexachlorobiphenyl (HCBP) using three freshwater benthic invertebrates. Hyalella azteca, Chironomus tentans, and Lumbriculus variegatus were exposed to BaP- and HCBP-spiked sediments that were aged for 7 d or 1.5 years. The toxicokinetics of the two compounds were determined for each test organism using a two-compartment model. The modeling of BaP was more complex because biotransformation was included within the model. The results of this study showed that the HCBP uptake clearance rates (k(s)) for each species were generally an order of magnitude greater than those determined for BaP and this difference was most likely due to preferential and rapid binding of BaP to sediment particles. Overall, the bioavailability of HCBP in spiked sediments tended to decrease with duration of aging, based on k(s) values and bioaccumulation factors (BAFs). However, the decreases in bioavailability appear to be species specific. Benzo[a]pyrene did not decline in bioavailability for the species tested because it may resist movement into the micropores of the sediment due to its large size. In addition to the bioassays, this article outlines a method for toxicokinetic modeling of biotransformed compounds and methods for statistical comparisons of kinetic parameters (i.e., k(s), k(d)...) and BAF values.

Adsorption↗

PubMed2003

Inverse relationship between bioconcentration factor and exposure concentration for metals: implications for hazard assessment of metals in the aquatic environment.

The bioconcentration factor (BCF) and bioaccumulation factor (BAF) are used as the criteria for bioaccumulation in the context of identifying and classifying substances that are hazardous to the aquatic environment. The BCF/BAF criteria, while developed as surrogates for chronic toxicity and/or biomagnification of anthropogenic organic substances, are applied to all substances including metals. This work examines the theoretical and experimental basis for the use of BCF/BAF in the hazard assessment of Zn, Cd, Cu, Pb, Ni, and Ag. As well, BCF/BAFs for Hg (methyl and inorganic forms) and hexachlorobenzene (HCB) were evaluated. The BCF/BAF data for Zn, Cd, Cu, Pb, Ni, and Ag were characterized by extreme variability in mean BCF/BAF values and a clear inverse relationship between BCF/BAF and aqueous exposure. The high variability persisted when even when data were limited to an exposure range where chronic toxicity would be expected. Mean BCF/BAF values for Hg were also variable, but the inverse relationship was equivocal, in contrast with HCB, which conformed to the BCF model. This study illustrates that the BCF/BAF criteria, as currently applied, are inappropriate for the hazard identification and classification of metals. Furthermore, using BCF and BAF data leads to conclusions that are inconsistent with the toxicological data, as values are highest (indicating hazard) at low exposure concentrations and are lowest (indicating no hazard) at high exposure concentrations, where impacts are likely. Bioconcentration and bioaccumulation factors do not distinguish between essential mineral nutrient, normal background metal bioaccumulation, the adaptive capabilities of animals to vary uptake and elimination within the spectrum of exposure regimes, nor the specific ability to sequester, detoxify, and store internalized metal from metal uptake that results in adverse effect. An alternative to BCF, the accumulation factor (ACF), for metals was assessed and, while providing an improvement, it did not provide a complete solution. A bioaccumulation criterion for the hazard identification of metals is required, and work directed at linking chronic toxicity and bioaccumulation may provide some solutions.

Analysis of Variance↗

PubMedDate not supplied

[Bronchoalveolar lavage in the diagnosis of occupational pulmonary diseases in miners].

One of objective methods of early and differential diagnosis of occupational pulmonary diseases in miners (pneumoconiosis, silicotuberculosis, dust bronchitis) is bronchoscopy with a cytologic examination of bronchoalveolar lavage fluid (BAF). BAF-examination was carried out in a total of 88 patients with incipient and advanced forms of dust bronchitis, pneumoconiosis and silicotuberculosis. A direct relationship has been revealed between a decline in local cell-bound immunity caused by a dust-inducted affection mononuclear phagocytes and advancing of stages of dust-related diseases.

Bronchitis↗

PubMed2000

[Cultural characteristics of some ectomycorrhizal fungi in pure culture].

Macro and microscopic features for 21 species of ectomycorrhizal fungi are presented, with regard to their particular importance as possible taxonomic criteria. The culture media used are MMN and BAF. Cultural characteristics of some of our isolates, like color or morphology of the mycelia, were comparable to those observed by different authors for the same species, or species which are closely related taxonomically, as for example Boletus satanas and Lactarius deliciosus in BAF media, or Hebeloma edurum, Lycoperdon perlatum, Paxillus atrotomentosus, Rhizopogon roseolus and Suillus collinitus in MMN media. Macroscopically the color of mycelia, the amount of aerial mycelia and microscopically the exudates and the presence of inflated and flexuous cells were the most variable characteristics within species.

English Abstract↗

PubMed2005

Effect of media heights on the performance of biological aerated filter.

The optimum media height of carbon oxidation and nitrification in a down-flow biological aerated filter was determined, and the distribution of the heterotrophic and nitrifying populations through studying the changes of organic carbon contents and ammonia concentration at different media height was got. The results showed that as a down flow BAF with granular media, the active layer of nitrifiers was deeper than heterotrophs in BAF. And the optimum media height for the removal of SS, COD(Cr) and NH4+ -N was 40 cm, 60 cm and 80 cm respectively. The removal efficiency of SS, COD(Cr), and NH4+ -N was 79.1%, 63.9% and 96.4% respectively under the influent COD(Cr), and NH4+ -N of 122.1 mgCOD(Cr)/L and 14.84 mgNH4+ -N/L, the influent flux of 15.8 L/h, air to liquid ratio of 3:1.

Ammonia↗

PubMed2005

[Experience of pediatric application of bifidumbacterin multi, a biologically active food supplement].

The article is dedicated to a clinical trial of Bifidumbacterin Multi-1, a biologically active food supplement (BAFS) for children aged 0 to 3 years. The study showed that application of BAFS in children with intestinal dysbiosis helped to cope with the symptoms of alimentary disturbances, promoted improvement of body mass index, increase of hemoglobin end erythrocyte level, suppression of zymotic and putrefactive dyspepsia, decrease of inflammation of the intestinal mucosa, elimination of bibidobacterial deficit, and reduction of conditionally pathogenic microflora. Bifidumbacterin Multi-1 was well tolerated and highly effective according to clinical and laboratory data. This preparation may be recommended as a component of complex therapy in children aged 0 to 3 years old.

Anti-Infective Agents↗

PubMed2005

Biological phosphorus and nitrogen removal with biological aerated filter using denitrifying phosphorus accumulating organism.

In order to accomplish the biological nutrient removal with a weak sewage at low temperature, a hybrid process consisted of anoxic denitrifying phosphorus accumulating organism (dPAO) and nitrifying biological aerated filter (BAF) was studied in both lab and field pilot plants with weak sewage. The biofilm BAF was used as a post-nitrification process that provided sufficient nitrate to suspended growth dPAO. The anoxic/BAF configuration could remove nitrogen and phosphorus appreciably compared to other BNR systems. The enhanced biological phosphorus removal (EBPR) was mainly occurred in anoxic zone of suspended growth reactor. It has been found that P removal efficiency of dPAO was enhanced with an addition of a short oxic zone in suspended reactors compared to that of without oxic zone. However, the degree of aerobic P uptake in oxic zone was far lower than anoxic P uptake. The operating results of field plant indicated that dPAO/BAF configuration successfully reduced the adverse temperature effects at lower than 15 degrees C.

Bacteria, Aerobic↗

PubMedDate not supplied

[The clinical and diagnostic value of some hemodynamic indices for the assessment of silent ischemia in patients with low myocardial contractility].

During initial anesthesia, central and peripheral hemodynamic parameters were studied in 32 patients operated on for coronary heart disease (CHD). The patients were divided into 3 groups: 1) those with < 35% ejection fraction (EF) with postinfarct left ventricular (LV) aneurysm (PLVA); 2) those with > 35% EF with PLVA; 3) those with > 35% EF without PLVA. All the examinees were assigned as having NYHA functional class III-IV. During the study, the authors examined central and peripheral hemodynamic parameters: ECG, invasive blood pressure (BP), pulmonary pressure, central venous pressure, and cardiac output. The findings were used to calculate cardiac index (CI) and its changes (CI). In addition, the indices of rate pressure product, a marker of myocardial contractility and the Buffington index (I baf) is a BPmean-heart rate ratio), a marker of possible myocardial ischemia, were calculated. To gain some insight into the role of ischemia in the reduction of SI in the examinees, the authors modified the index I baf: they used the index perfusion pressure in the coronary bed instead of BPmean in the formula.

Anesthesia, General↗

PubMed1989

[Bile fractions and bile secretory component of the migrating myoelectric complex in dogs].

In 4 dogs the functional cholecystectomy was performed, then the common bile duct was cannulated and 9 bipolar electrodes were implanted into the stomach and small intestine. During the interdigestive period when the experiments were carried out both bile flow and electric activity of the gastrointestinal tract were monitored under the following conditions: 1) short or long bile depletion periods, 2) intraduodenal infusions of 50 mM sodium taurocholate, sodium taurodeoxycholate or sodium taurochenodeoxycholate, 3) intraduodenal bile infusions. Total bile acid content was determined in bile samples, then both bile acid-dependent (BAF) and bile acid-independent fractions (BAIF) of bile were calculated. The appearance of the bile secretory component was in 65% correlated with phase III of the MMC while the height of its amplitude usually exceeded 100% of the initial value. In all experimental groups the marked increase in BAIF was followed by a slight enhancement of BAF or its absence. Fluctuations of the biliary fractions were determined by a degree of depletion of the systemic bile acid pool. The changes described were more distinct during infusions of dihydroxy bile acids. The results suggest the importance of BAIF in the appearance of the bile secretory component of the MMC.

Action Potentials↗

PubMed1979

The problem of interaction of shigella with epithelial cells.

A review and analysis of data on the investigation of factors concerning the initial events of interaction of Shigella with epithelial cells: attachment of penetration are presented. In the experiments with 3H-labeled bacteria it was shown that although common pili confer adhesive properties to bacteria but the penetration of Shigella into the cell is not increased. It was stated that LPS of Shigella O antigen plays an important role not only in interaction with cellular and humoral factors of the macroorganism defence but also in an initial stage of attachment of bacteria to the membrane of epithelial cells. However LPS of O antigen does not provide the penetration of the agent into the cell. In filtrates of virulent strains of Shigella flexneri, in contrast to those of smooth mutants and hybrids, lacking penetration ability, a biologically active factor (BAF) of protein or lipoprotein nature which reduced the LD50 of virulent and avirulent bacteria in infection of chicken embryos on chorioallantoic membrane, decreases ID50 and complicates the course of the infectious process in conjunctival infection of guinea pigs with virulent Shigella strain was revealed. S. flexneri transductant with a restored ability to induce kerato-conjunctivitis restored an ability to produce the BAF as well. Comparison of these data with the findings of other investigators was carried out. Perspectives of interpretation of penetration mechanism of Shigella into epithelial cells are discussed.

Antigens, Bacterial↗

PubMed1980

Comparative distribution of Baker's antifolate (NSC 139105) in rat tissues after subcutaneous and intravenous injections.

The tissue distribution of BAF was compared by intravenous and subcutaneous injections in rats bearing Walker 256 carcinoma. Following a single dose (6 mg/kg containing 30 microCi 4,6-di-14C-BAF), the drug concentrations were determined by radiochemical and dihydrofolate reductase assays. The two methods gave comparable results. No metabolites were found by paper chromatographic separations.

Animals↗

PubMed1994

Erythropoietin receptor and interleukin-2 receptor use different downstream signaling pathways for proliferation and apoptosis-block.

Erythropoietin (EPO) regulates proliferation and differentiation and prevents apoptosis of erythroid progenitor cells by binding to erythropoietin receptor (EPOR) expressed on the surface of those cells. The mechanism by which EPO signal is transmitted to the cells through EPOR is still unclear. In the present study, we introduced and expressed EPOR in an interleukin-3 (IL-3) dependent pro-B cell line, BAF-B03 and an interleukin-2 (IL-2)-dependent cytotoxic T cell line, CTLL-2 and analyzed their growth response to EPO and the DNA breakdown characteristic to apoptosis after deprivation of the growth factor. BAF-B03-derived cells expressing EPOR proliferated in response to EPO but CTLL-2-derived cells expressing EPOR (C/EPOR) did not. DNA from C/EPOR cells cultured in the absence of IL-2 with or without EPO had similar patterns of DNA breakdown. These results suggest that downstream signaling pathways for the cell proliferation and apoptosis-block are, at least, partially different between EPOR and IL-2 receptor (IL-2R).

Animals↗

PubMed1994

Evaluation of different medium supplements for in vitro cultivation of Brugia malayi third-stage larvae.

Growth and development of Brugia malayi (Nematoda: Filarioidea) third-stage larvae (L3) were compared in 5 medium supplements. The basic culture medium (NI) consisted of a 1:1 (v/v) mixture of NCTC-135 and Iscove's modified Dulbecco's medium, an antibiotic/antimycotic mixture, and 1 of the following 5 supplements: 25 mg/ml bovine albumin fraction-V (BAF), 10% fetal bovine serum (FBS), 10% commercially obtained human serum (CHS), 10-15% pooled human serum from hospital patients (PHS), and 10-15% human serum from a single individual (SHS). Cultures were maintained at 37 C in an atmosphere of 5% CO2 in air. NI-BAF and NI-CHS did not support molting of L3 to fourth-stage larvae (L4), whereas NI-FBS, NI-PHS, and NI-SHS did support molting of L3 to L4 but only the larvae in NI-SHS attempted the fourth molt. Growth and development of in vitro larvae in NI-PHS and NI-SHS were comparable to that observed in jirds for the first 28 days, after which the in vitro larvae lagged behind in vivo larvae. Optimal growth and development may be dependent on certain as yet unidentified components of specific human serum.

Animals↗

PubMed1993

The serine-rich cytoplasmic domain of the interleukin-2 receptor beta chain is essential for interleukin-2-dependent tyrosine protein kinase and phosphatidylinositol-3-kinase activation.

The biological activity of interleukin-2 receptors (IL-2R) is dependent on the functional coupling of IL-2R beta molecules to intracellular enzymes such as protein tyrosine kinase. The serine-rich, S-domain within the cytosolic portion of IL-2R beta plays an essential role in transduction of the IL-2 proliferative signal. Cells bearing either wild type IL-2R beta (Baf alpha/beta) or deletions within the S-domain (Baf alpha/beta SD1) were used to evaluate the importance of the S-domain in linking ligand binding to protein tyrosine kinase induction. Multiparameter, side by side comparisons showed that only those cells that expressed wild type IL-2R beta responded to IL-2 by increased cellular proliferation, accumulation of the c-myc proto-oncogene, and activation of protein tyrosine kinase. Activation of protein tyrosine kinase was, in turn, linked to increased tyrosine phosphorylation and activation of phosphatidylinositol-3-kinase. These findings indicate that the S-domain of the IL-2R beta chain is an essential component in the signal transduction cascade that links IL-2 binding to tyrosine kinase and phosphatidylinositol-3-kinase activation.

1-Phosphatidylinositol 4-Kinase↗

PubMed1993

Cell penetration of diphtheria toxin. Reduction of the interchain disulfide bridge is the rate-limiting step of translocation in the cytosol.

The pathway of cell penetration of diphtheria toxin (DT) was studied in Vero cells by following the kinetics of uptake, reduction, degradation, and sub-cellular distribution of 125I-DT in the absence or presence of bafilomycin A1 (baf-A1), a powerful inhibitor of the endosomal H(+)-ATPase. After a lag phase of 4 min, DT, bound to Vero cells, reached an acidic intracellular compartment, where about one-third of it underwent a transition to a state competent for subsequent reduction and membrane translocation. After further 4 min, this DT fraction was reduced in a baf-A1-insensitive reaction and DT-A, the intracellularly active protomer of DT, was immediately released in the cytosol. The present data indicate that cell-mediated reduction of the toxin is the rate-determining step of the DT cell intoxication process. Subcellular fractionation showed that DT underwent the low pH-driven conformational change in an early endosome, distinct from the subsequent endosomal compartment where reduction took place. DT-B remained endosome-bound and was proteolyzed at low pH as well as the portion of DT which was not reduced after the exposure to low pH in early endosomes.

Animals↗

PubMed1996

Purification and biochemical heterogeneity of the mammalian SWI-SNF complex.

We have purified distinct complexes of nine to 12 proteins [referred to as BRG1-associated factors (BAFs)] from several mammalian cell lines using an antibody to the SWI2-SNF2 homolog BRG1. Microsequencing revealed that the 47 kDa BAF is identical to INI1. Previously INI1 has been shown to interact with and activate human immunodeficiency virus integrase and to be homologous to the yeast SNF5 gene. A group of BAF47-associated proteins were affinity purified with antibodies against INI1/BAF47 and were found to be identical to those co-purified with BRG1, strongly indicating that this group of proteins associates tightly and is likely to be the mammalian equivalent of the yeast SWI-SNF complex. Complexes containing BRG1 can disrupt nucleosomes and facilitate the binding of GAL4-VP16 to a nucleosomal template similar to the yeast SWI-SNF complex. Purification of the complex from several cell lines demonstrates that it is heterogeneous with respect to subunit composition. The two SWI-SNF2 homologs, BRG1 and hbrm, were found in separate complexes. Certain cell lines completely lack BRG1 and hbrm, indicating that they are not essential for cell viability and that the mammalian SWI-SNF complex may be tailored to the needs of a differentiated cell type.

Amino Acid Sequence↗

PubMed1977

Phase II trial of Baker's antifol in metastatic sarcoma.

Iv Baker's antifol (BAF) (250 mg/m2/day X 3 consecutive days) was administered to 34 patients with metastatic sarcoma. All patients had received extensive prior therapy including prior chemotherapy and had progressive disease at the start of the study. Liver and renal functions were normal in all patients. Of 29 patients evaluable for response, 25 demonstrated progressive disease and four had stable disease for periods of from 1 to 6 months. No objective responses were observed. The other five patients died from 3 to 12 days after initiation of therapy. Toxicity included myelosuppression of significant degree in nine patients, gastrointestinal effects of nausea and vomiting in seven, stomatitis in three, and dermatitis in four. Most toxicity was mild to moderate, although one drug-related death due to marked myelosuppression was seen. In conclusion, BAF is considered to be insignificantly active in the secondary treatment of metastatic sarcomas at the dose and schedule studied.

Antineoplastic Agents↗