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1.
J Mater Chem B ; 9(1): 101-111, 2021 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-33232438

RESUMO

Near infrared (NIR) light detonated phototherapy for cancer treatment based on photothermal therapy (PTT) and photodynamic therapy (PDT) has attracted increasing attention owing to its deep tissue penetration. However, the low absorption ability and therapeutic efficiency of the photosensitive drug have restricted the development of phototherapy to a great degree. Herein, a kind of IR808 dye sensitized glutathione (GSH) cladded Au-Bi bimetallic nanoparticles (Au-Bi-GSH@IR808) was prepared to enhance the inhibition effect of tumors. In this nanoplatform, the construction of GSH cladded Au-Bi bimetallic nanoparticles can effectively generate 1O2 while exhibiting outstanding photothermal conversion efficiency (η = 34.2%) upon 808 nm laser irradiation. Furthermore, IR808 as a small molecule dye endows the Au-Bi-GSH@IR808 with a higher 808 nm light absorption ability and stronger photothermal and photodynamic effects. The IR808 sensitized Au-Bi bimetallic nanoparticles with a small size (5 nm), hydrophilia and dispersible nature, exhibit a noticeably enhanced therapeutic peculiarity. Additionally, the prominent CT imaging property of Au-Bi-GSH@IR808 means it is expected to be used as a CT imaging contrast agent in clinical applications. The results of the in vitro and in vivo experiments indicate that the synthesized nanoparticles have an excellent ablation effect on cancer cells, and they are expected to be widely used in the accurate diagnosis and treatment of cancer.


Assuntos
Bismuto/metabolismo , Ouro/metabolismo , Nanopartículas Metálicas , Fotoquimioterapia/métodos , Fototerapia/métodos , Compostos de Sulfidrila/metabolismo , Animais , Bismuto/administração & dosagem , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Relação Dose-Resposta a Droga , Feminino , Ouro/administração & dosagem , Nanopartículas Metálicas/administração & dosagem , Camundongos , Imagem Molecular/métodos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Compostos de Sulfidrila/administração & dosagem
2.
Biomater Sci ; 7(8): 3450-3459, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31268067

RESUMO

Bismuth-containing nanoparticles (BNPs) are potential enhancers for tumor radiotherapy. Improving the bioavailability and developing synergistic therapeutic regimens benefit the drug transformation of BNPs. In the present study, we prepare a mesoporous silica-coated bismuth nanorod (BMSNR) camouflaged by a platelet membrane (PM). This biomimetic material is termed BMSNR@PM. The PM camouflage enhances the immune escape of the BMSNRs by lowering endocytosis by macrophages in the reticuloendothelial system. Additionally, the PM camouflage strengthens the material tumor-targeting capacity and leads to better radiotherapeutic efficacy compared with bare BMSNRs. Owing to the photothermal effect, BMSNR@PMs alters the cell cycle of 4T1 cancer cells post-treatment with 808 nm near-infrared irradiation (NIR). The proportions of S phase and G2/M phase cells decrease and increase, respectively, which explains the synergistic effect of NIR on BMSNR@PM-based radiotherapy. BMSNR@PMs efficiently eradicates cancer cells by the combined action of photothermal therapy (PTT) and radiotherapy in vivo and markedly improves the survival of 4T1-tumor-bearing mice. The synergistic therapeutic effect is superior to the outcomes of PTT and radiotherapy performed alone. Our study demonstrates a versatile bismuth-containing nanoplatform with tumor-targeting, immune escape, and radiosensitizing functionalities using an autologous cell membrane biomimetic concept that may promote the development of radiotherapy enhancers.


Assuntos
Bismuto/química , Bismuto/farmacologia , Plaquetas/citologia , Neoplasias da Mama/terapia , Membrana Celular/metabolismo , Nanotubos/química , Fototerapia , Sulfetos/química , Sulfetos/farmacologia , Animais , Bismuto/metabolismo , Neoplasias da Mama/patologia , Neoplasias da Mama/radioterapia , Linhagem Celular Tumoral , Terapia Combinada , Endocitose , Feminino , Humanos , Macrófagos/metabolismo , Camundongos , Nanocompostos/química , Porosidade , Células RAW 264.7 , Radiossensibilizantes/química , Radiossensibilizantes/metabolismo , Radiossensibilizantes/farmacologia , Dióxido de Silício/química , Sulfetos/metabolismo
3.
IET Nanobiotechnol ; 13(4): 377-381, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31171741

RESUMO

In the present study Delftia sp. Shakibaie, Forootanfar, and Ghazanfari (SFG), was applied for preparation of biogenic Bi nanoparticles (BiNPs) and antibacterial and anti-biofilm activities of the purified BiNPs were investigated by microdilution and disc diffusion methods. Transmission electron micrographs showed that the produced nanostructures were spherical with a size range of 40-120 nm. The measured minimum inhibitory concentration of both the Bi subnitrate and BiNPs against three biofilms producing bacterial pathogens of Staphylococcus aureus, Pseudomonas aeruginosa, and Proteus mirabilis were found to be above 1280 µg/ml. Addition of BiNPs (1000 µg/disc) to antibiotic discs containing tobramycin, nalidixic acid, ceftriaxone, bacitracin, cefalexin, amoxicillin, and cefixime significantly increased the antibacterial effects against methicillin-resistant S. aureus (MRSA) in comparison with Bi subnitrate (p < 0.05). Furthermore, the biogenic BiNPs decreased the biofilm formation of S. aureus, P. aeruginosa, and P. mirabilis to 55, 85, and 15%, respectively. In comparison to Bi subnitrate, BiNPs indicated significant anti-biofilm activity against P. aeruginosa (p < 0.05) while the anti-biofilm activity of BiNPs against S. aureus and P. mirabilis was similar to that of Bi subnitrate. To sum up, the attained results showed that combination of biogenic BiNPs with commonly used antibiotics relatively enhanced their antibacterial effects against MRSA.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Bismuto/farmacologia , Delftia/química , Nanopartículas/toxicidade , Antibacterianos/química , Antibacterianos/metabolismo , Bactérias/efeitos dos fármacos , Bismuto/química , Bismuto/metabolismo , Delftia/metabolismo , Testes de Sensibilidade Microbiana , Nanopartículas/química , Nanopartículas/metabolismo , Extratos Vegetais/química , Extratos Vegetais/metabolismo
4.
Nat Commun ; 9(1): 439, 2018 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-29382822

RESUMO

Drug-resistant superbugs pose a huge threat to human health. Infections by Enterobacteriaceae producing metallo-ß-lactamases (MBLs), e.g., New Delhi metallo-ß-lactamase 1 (NDM-1) are very difficult to treat. Development of effective MBL inhibitors to revive the efficacy of existing antibiotics is highly desirable. However, such inhibitors are not clinically available till now. Here we show that an anti-Helicobacter pylori drug, colloidal bismuth subcitrate (CBS), and related Bi(III) compounds irreversibly inhibit different types of MBLs via the mechanism, with one Bi(III) displacing two Zn(II) ions as revealed by X-ray crystallography, leading to the release of Zn(II) cofactors. CBS restores meropenem (MER) efficacy against MBL-positive bacteria in vitro, and in mice infection model, importantly, also slows down the development of higher-level resistance in NDM-1-positive bacteria. This study demonstrates a high potential of Bi(III) compounds as the first broad-spectrum B1 MBL inhibitors to treat MBL-positive bacterial infection in conjunction with existing carbapenems.


Assuntos
Anti-Infecciosos/farmacologia , Compostos Organometálicos/farmacologia , Inibidores de beta-Lactamases/farmacologia , beta-Lactamases/metabolismo , Animais , Anti-Infecciosos/química , Bismuto/química , Bismuto/metabolismo , Bismuto/farmacologia , Carbapenêmicos/farmacologia , Domínio Catalítico , Cristalografia por Raios X , Cães , Avaliação Pré-Clínica de Medicamentos/métodos , Evolução Molecular , Feminino , Células Madin Darby de Rim Canino/efeitos dos fármacos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Compostos Organometálicos/química , Peritonite/tratamento farmacológico , Peritonite/microbiologia , Zinco/metabolismo , Resistência beta-Lactâmica/efeitos dos fármacos , beta-Lactamases/química
5.
Lett Appl Microbiol ; 59(2): 217-23, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24712346

RESUMO

UNLABELLED: Biovolatilization and bioaccumulation capabilities of different elements by microscopic filamentous fungus Scopulariopsis brevicaulis were observed. Accumulation of As(III), As(V), Se(IV), Se(VI), Sb(III), Sb(V), Te(IV), Te(VI), Hg(II), Tl(I) and Bi(III) by S. brevicaulis was quantified by analysing the amount of elements in biomass of the fungus using ICP AAS. The highest amounts of bioaccumulated metal(loid)s were obtained as follows: Bi(III) > Te(IV) > Hg(II) > Se(IV) > Te(VI) > Sb(III) at different initial contents, with Bi(III) accumulation approximately 87%. The highest percentages of volatilization were found using Hg(II) (50%) and Se(IV) (46·5%); it was also demonstrated with all studied elements. This proved the biovolatilization ability of microscopic fungi under aerobic conditions. The highest removed amount was observed using Hg(II) (95·30%), and more than 80% of Se(IV), Te(IV), Bi(III) and Hg(II) was removed by bioaccumulation and biovolatilization, which implies the possibilities of use of these processes for bioremediations. There were reported significant differences between bioaccumulation and biovolatilization of almost all applied metal(loid)s if valence is mentioned. SIGNIFICANCE AND IMPACT OF THE STUDY: Microbial accumulation and volatilization are natural processes involved in biogeochemical cycles of elements. Despite their impact on mobility, bioavailability and toxicity of various metal(loid)s, only few papers deal with these processes under aerobic conditions with microscopic fungi. Thus, the proving of ability of microscopic fungus Scopulariopsis brevicaulis to accumulate and transform metals and metalloids by methylation or alkylation and quantification of these processes were demonstrated. The results can provide basic information on natural elements cycling and background for more specific studies focusing, for example, on application of these processes in mitigation of metal(loid) contamination.


Assuntos
Scopulariopsis/metabolismo , Antimônio/metabolismo , Biodegradação Ambiental , Bismuto/metabolismo , Mercúrio/metabolismo , Scopulariopsis/crescimento & desenvolvimento , Selênio/metabolismo , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/metabolismo , Telúrio/metabolismo , Volatilização
6.
Chem Commun (Camb) ; 48(64): 7952-4, 2012 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-22760735

RESUMO

Fibrinogen-modified bismuth-gold nanoparticles (Fib-Bi-Au NPs) are prepared and used as enzyme mimics for the H(2)O(2)-mediated reaction with Amplex Red (AR), which is further employed for determining thrombin activity and drug screening.


Assuntos
Materiais Biomiméticos/química , Bismuto/química , Ouro/química , Nanopartículas Metálicas/química , Peroxidase/metabolismo , Trombina/metabolismo , Materiais Biomiméticos/metabolismo , Bismuto/metabolismo , Avaliação Pré-Clínica de Medicamentos , Ouro/metabolismo , Peróxido de Hidrogênio/química , Oxazinas/química , Oxirredução , Peroxidase/química , Trombina/antagonistas & inibidores
7.
Biochim Biophys Acta ; 1820(3): 334-47, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21872645

RESUMO

BACKGROUND: For a metal to follow the iron acquisition pathway, four conditions are required: 1-complex formation with transferrin; 2-interaction with receptor 1; 3-metal release in the endosome; and 4-metal transport to cytosol. SCOPE OF THE REVIEW: This review deals with the mechanisms of aluminum(III), cobalt(III), uranium(VI), gallium(III) and bismuth(III) uptake by transferrin and interaction with receptor 1. MAJOR CONCLUSIONS: The interaction of the metal-loaded transferrin with receptor 1 takes place in one or two steps: a very fast first step (µs to ms) between the C-lobe and the helical domain of the receptor, and a second slow step (2-6h) between the N-lobe and the protease-like domain. In transferrin loaded with metals other than iron, the dissociation constants for the interaction of the C-lobe with TFR are in a comparable range of magnitudes 10 to 0.5µM, whereas those of the interaction of the N-lobe are several orders of magnitudes lower or not detected. Endocytosis occurs in minutes, which implies a possible internalization of the metal-loaded transferrin with only the C-lobe interacting with the receptor. GENERAL SIGNIFICANCE: A competition with iron is possible and implies that metal internalization is more related to kinetics than thermodynamics. As for metal release in the endosome, it is faster than the recycling time of transferrin, which implies its possible liberation in the cell. This article is part of a Special Issue entitled Transferrins: Molecular mechanisms of iron transport and disorders.


Assuntos
Metais/metabolismo , Receptores da Transferrina/metabolismo , Transferrina/metabolismo , Alumínio/metabolismo , Animais , Bismuto/metabolismo , Cobalto/metabolismo , Endocitose , Gálio/metabolismo , Humanos , Íons/metabolismo , Ferro/metabolismo , Ligação Proteica , Estrutura Terciária de Proteína , Transferrina/química , Urânio/metabolismo
8.
Toxicol Ind Health ; 24(4): 235-40, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-19022876

RESUMO

Consumption and production of bismuth compounds are increasing, however, a little information on the toxic effect and also the effective method in removal of bismuth compounds are available. The present research aimed to characterize the potential efficiency of two chelators after bismuth administration for 55A days following two dose levels of 20 and 40A mg/kg body weight daily to male rats. However, we found abnormalities after bismuth administration in clinical signs, such as body weight, kidneys and liver damages, a black line on gums and skin reactions. Furthermore, the hypothesis that the two chelators might be more efficient as combined therapy than as single therapy in removing bismuth from the body was considered. Along this line, two known chelators deferiprone (1, 2-dimethy1-3-hydroxypyride-4-one, L(1)) and desferrioxamine (DFO) were chosen and tested in the acute rat model. Chelators were given orally (L(1)) or intraperitoneally (DFO) as a single or combined therapy for the period of a week. Doses of L(1) and DFO were 110A mg/kg body weight in experiments. Bismuth and iron concentrations in various tissues were determined by graphite furnace and flame atomic absorption spectrometry, respectively. The combined chelation therapy results show that DFO and L(1) are able to remove bismuth ions from the body, whereas iron concentration returned to the normal level and symptoms are also decreased. DFO was more effective than L1 in reducing bismuth concentration in tissues. The efficiency of DFOA +A L(1) is more than DFO or L(1) in removing bismuth from organs. Our results are indicative that the design procedure might be useful for preliminary in-vivo testing of the efficiency of chelating agents. Results of combined chelators' treatment should be confirmed in a different experimental model before extrapolation to other systems. This testing procedure of course does not provide all the relevant answers for efficiency of chelating agents in bismuth toxicity.


Assuntos
Bismuto/metabolismo , Desferroxamina/uso terapêutico , Quelantes de Ferro/uso terapêutico , Piridonas/uso terapêutico , Sideróforos/uso terapêutico , Animais , Bismuto/farmacocinética , Bismuto/toxicidade , Peso Corporal/efeitos dos fármacos , Terapia por Quelação/métodos , Deferiprona , Quimioterapia Combinada , Ingestão de Alimentos/efeitos dos fármacos , Ferro/análise , Ferro/metabolismo , Rim/metabolismo , Masculino , Ratos , Ratos Wistar
9.
Syst Appl Microbiol ; 31(2): 81-7, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18396004

RESUMO

As shown by recent studies, anaerobic members of Archaea and Bacteria are involved in processes that transform ionic species of metals and metalloids (arsenic, antimony, bismuth, selenium, tellurium and mercury) into volatile and mostly toxic derivatives (mainly methyl derivatives or hydrides). Since the fact that these transformations proceed in both environmental settings and in parts of the human body, we have to consider that these processes also interfere directly with human health. The diversity of the volatile derivatives produced and their emission rates were significantly higher in methanoarchaeal than in bacterial strains, which supports the pivotal role of methanoarchaea in transforming metals and metalloids (metal(loid)s) into their volatile derivatives. Compared with methanoarchaea, 14 anaerobic bacterial strains showed a significantly restricted spectrum of volatilised derivatives and mostly lower production rates of volatile bismuth and selenium derivatives. Since methanoarchaea isolated from the human gut (Methanosphaera stadtmanae, Methanobrevibacter smithii) showed a higher potential for metal(loid) derivatisation compared to bacterial gut isolates, we assume that methanoarchaea in the human gut are mainly responsible for the production of these volatile derivatives. The observation that trimethylbismuth ((CH(3))(3)Bi), the main volatile derivative of bismuth produced in human feces, inhibited growing cultures of Bacteroides thetaiotaomicron, a representative member of the human physiological gut flora, suggests that these volatiles exert their toxic effects on human health not only by direct interaction with host cells but also by disturbing the physiological gut microflora.


Assuntos
Bismuto/metabolismo , Metano/metabolismo , Methanobacteriaceae/metabolismo , Methanobrevibacter/metabolismo , Selênio/metabolismo , Bactérias Anaeróbias/crescimento & desenvolvimento , Bactérias Anaeróbias/metabolismo , Humanos , Volatilização
10.
J Am Soc Mass Spectrom ; 15(11): 1658-64, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15519234

RESUMO

Transferrins comprise a class of monomeric glycoproteins found in all vertebrates, whose function is iron sequestration and transport. In addition to iron, serum transferrin also binds a variety of other metals and is believed to provide a route for the in vivo delivery of such metals to cells. In the present study, ESI MS is used to investigate interactions between human serum transferrin and two nonferrous metals, indium (a commonly used imaging agent) and bismuth (a component of many antiulcer drugs). While the UV-Vis absorption spectroscopy measurements clearly indicate that both metals bind strongly to transferrin in solution, the metal-protein complex can be detected by ESI MS only for indium, but not for bismuth. Despite the apparently low stability of the transferrin-bismuth complex in the gas phase, presence of such complex in solution can be established by ESI MS indirectly. This is done by monitoring the evolution of charge state distributions of transferrin ions upon acid-induced protein unfolding in the presence and in the absence of the metal in solution. The anomalous instability of the transferrin-bismuth complex in the gas phase is rationalized in terms of conformational differences between this form of transferrin and the holo-forms of this protein produced by binding of metals with smaller ionic radii (e.g., Fe3+ and In3+). The large size of Bi3+ ion is likely to prevent formation of a closed conformation (canonical structure of the holo-protein), resulting in a non-native metal coordination. It is suggested that transferrin retains the open conformation (characteristic of the apo-form) upon binding Bi3+, with only two ligands in the metal coordination sphere provided by the protein itself. This suggestion is corroborated by the results of circular dichroism measurements in the near-UV range. Since the cellular consumption of metals in the transferrin cycle critically depends upon recognition of the holo-protein complex by the transferrin receptor, the noncanonical conformation of the transferrin-bismuth complex may explain very inefficient delivery of bismuth to cells even when a high dosage of bismuth-containing drugs is administered for prolonged periods of time.


Assuntos
Bismuto/química , Índio/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Transferrina/química , Bismuto/metabolismo , Humanos , Índio/metabolismo , Ligação Proteica , Transferrina/metabolismo
11.
J Biol Inorg Chem ; 7(4-5): 551-9, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11941514

RESUMO

Staphylococcus aureus pI258 CadC is a metal sensor protein that regulates the expression of the cad operon which encodes metal ion resistance proteins involved in the efficient efflux of Cd(II), Pb(II), Zn(II) and, according to one report, Bi(III) ions. In this paper, direct evidence is presented that Bi(III) binds to CadC and negatively regulates cad operator/promoter (O/P) binding. Optical absorption spectroscopy reveals that dimeric CadC binds approximately 0.8 mol equivalents of Bi(III) per CadC monomer to form a coordination complex characterized by three S(-)-->Bi(III) ligand-to-metal charge transfer transitions, with the longest wavelength absorption band centered at 415 nm (epsilon(415)=4000 M(Bi)(-1) cm(-1)). UV-Vis absorption spectra of wild-type and mutant Cys-->Gly (Ser) substitution CadC mutants compared to [Bi(DTT)(2)], [Bi(GSH)(3)] and [Bi(NAC)](3) model complexes reveal that Cys7, Cys11, Cys60 and Cys58 directly coordinate Bi(III) in a tetrathiolate coordination complex. The apparent affinity derived from a Bi(III)-displacement optical titration with Cd(II) is estimated to be K(Bi)< or =10(12) M(-1). Apo-CadC binds with high affinity [ K(a)=1.1(+/-0.3)x10(9) M(-1); 0.40 M NaCl, pH 7.0, 25 degrees C] to a 5'-fluorescein-labeled cad O/P oligonucleotide,while the binding of one molar equivalent of Bi(III) per CadC monomer (Bi(1)-CadC) reduces the affinity by approximately 170-fold. Strikingly, Bi(III)-responsive negative regulation of cad O/P binding is abrogated for Bi(1)-C60G CadC and severely disrupted in Bi(1)-C7G CadC, whose relative affinity is reduced only 10-fold. The mechanism of Bi(III)-responsive metalloregulation is discussed, based on the findings presented here. Electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00775-001-0336-9.


Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Bismuto/metabolismo , Proteínas Repressoras/química , Proteínas Repressoras/metabolismo , Staphylococcus aureus/química , Proteínas de Bactérias/genética , Sítios de Ligação , Bismuto/química , Cisteína/genética , Dimerização , Fluorescência , Regulação Bacteriana da Expressão Gênica , Glicina/genética , Modelos Moleculares , Óperon , Mutação Puntual , Regiões Promotoras Genéticas , Conformação Proteica , Espectrofotometria/métodos
12.
J Histochem Cytochem ; 48(11): 1503-10, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11036093

RESUMO

We provide a detailed protocol of the autometallographic bismuth technique and evaluate the specificity of the technique. We show by the multi-element technique "proton-induced X-ray microanalysis" (PIXE) that the autometallographic grains contain silver, bismuth, and sulfur, proving that autometallography can be used for specific tracing of bismuth bound as bismuth sulfide clusters in tissue sections from Bi-exposed animals or humans. In sections from animals exposed concurrently to selenium and bismuth, the autometallographic grains also contain selenium. This demonstrates that, if present in excess in the organisms, selenium will bind to exogenous bismuth, creating bismuth selenide clusters. As a further possible control for specificity and as a tool for differentiating among autometallographically detectable metals in sections containing more than one, we describe how bismuth sulfide clusters can be removed from Epon-embedded tissue sections by potassium cyanide.


Assuntos
Bismuto/metabolismo , Animais , Bismuto/química , Bismuto/toxicidade , Técnicas In Vitro , Indicadores e Reagentes , Camundongos , Camundongos Endogâmicos BALB C , Especificidade de Órgãos , Cianeto de Potássio , Ratos , Ratos Wistar , Selênio/química , Selênio/metabolismo , Selênio/toxicidade , Coloração pela Prata/métodos , Espectrometria por Raios X , Sulfetos/química
13.
Appl Environ Microbiol ; 66(7): 2791-6, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10877769

RESUMO

Gases released from anaerobic wastewater treatment facilities contain considerable amounts of volatile methyl and hydride derivatives of metals and metalloids, such as arsine (AsH(3)), monomethylarsine, dimethylarsine, trimethylarsine, trimethylbismuth (TMBi), elemental mercury (Hg(0)), trimethylstibine, dimethyltellurium, and tetramethyltin. Most of these compounds could be shown to be produced by pure cultures of microorganisms which are representatives of the anaerobic sewage sludge microflora, i.e., methanogenic archaea (Methanobacterium formicicum, Methanosarcina barkeri, Methanobacterium thermoautotrophicum), sulfate-reducing bacteria (Desulfovibrio vulgaris, D. gigas), and a peptolytic bacterium (Clostridium collagenovorans). Additionally, dimethylselenium and dimethyldiselenium could be detected in the headspace of most of the pure cultures. This is the first report of the production of TMBi, stibine, monomethylstibine, and dimethylstibine by a pure culture of M. formicicum.


Assuntos
Clostridium/metabolismo , Desulfovibrio/metabolismo , Euryarchaeota/metabolismo , Metais/metabolismo , Compostos Organometálicos/metabolismo , Esgotos/química , Esgotos/microbiologia , Anaerobiose , Antimônio/metabolismo , Archaea/crescimento & desenvolvimento , Archaea/metabolismo , Arsênio/metabolismo , Arsenicais/metabolismo , Biodegradação Ambiental , Bismuto/metabolismo , Clostridium/crescimento & desenvolvimento , Desulfovibrio/crescimento & desenvolvimento , Euryarchaeota/crescimento & desenvolvimento , Selênio/metabolismo , Telúrio/metabolismo , Volatilização
14.
J Lab Clin Med ; 119(5): 529-37, 1992 May.
Artigo em Inglês | MEDLINE | ID: mdl-1583409

RESUMO

Although bismuth poisoning is still a rare phenomenon, the increasing use of bismuth-containing drugs warrants a systematic approach to the treatment of bismuth overdose. An effective method of enhancing the elimination of toxic amounts of bismuth from the body has not been reported. Therefore we performed a study to select the best chelator to treat bismuth poisoning. Dimercaprol (BAL), meso-2,3-dimercaptosuccinic acid (DMSA), D,L-2,3-dimercapto-propane-I-sulfonic acid (DMPS), D-penicillamine (D-PEN), N-acetyl-D,L-penicillamine (Ac-PEN), thiopronine (TP), sodium-calcium edetate (EDTA) and deferoxamine (DFO) were tested with an in vitro model of equilibrium dialysis and an in vivo model of rats poisoned with bismuth. The rats (n = 6 per substance tested) were treated with the chelators in intraperitoneal doses of 250 mumol/kg.day for 3 consecutive days. Afterward, tissue and blood samples were collected. Bismuth concentrations were determined with electrothermal atomic absorption spectrometry in serum, buffer, urine, blood, brain, kidney, liver, spleen, and bone. Using in vitro results, we constructed a ranking of chelating agents; it appeared not to predict the in vivo results. The dithiol compounds (DMPS, DMSA and BAL) were effective in most organs (especially in kidney and liver) resulting in a higher elimination of bismuth in urine by DMPS and BAL. BAL was the only chelator effective in lowering brain bismuth concentrations, whereas treatment with EDTA resulted in increased brain bismuth levels. For D-PEN and DFO, no effects could be demonstrated. For clinical practice, DMSA and DMPS may well be the chelators of choice; the application of BAL should be reserved for very severe cases of poisoning because of its own toxicity.


Assuntos
Bismuto/toxicidade , Quelantes/uso terapêutico , Animais , Transporte Biológico , Bismuto/metabolismo , Feminino , Ligação Proteica , Ratos , Ratos Endogâmicos , Fatores de Tempo , Distribuição Tecidual
16.
Clin Exp Pharmacol Physiol ; 7(3): 319-24, 1980.
Artigo em Inglês | MEDLINE | ID: mdl-7398137

RESUMO

1. A colloidal bismuth preparation, tripotassium dicitrato-bismuthate, was given (172 mg/kg body weight, 6/7 days) to 10 laboratory rats for 14 months. Bismuth was measured by atomic absorption spectrometry in various tissues and the pattern of distribution studied. 2. Bismuth was present in kidney lung, spleen, liver, brain, heart and skeletal muscles, in descending order of abundance. Haematological data, renal and liver function tests were normal in the bismuth-treated group. 3. The data suggested that chronic ingestion of bismuth in large doses in rats results in absorption and binding to tissues. Absorbed bismuth probably crosses the blood-brain barrier.


Assuntos
Bismuto/metabolismo , Animais , Bilirrubina/sangue , Bismuto/sangue , Contagem de Células Sanguíneas , Enzimas/sangue , Hemoglobinas/metabolismo , Contagem de Leucócitos , Masculino , Ratos , Reticulócitos , Distribuição Tecidual , Ureia/sangue
17.
Arch Toxicol ; 40(2): 131-41, 1978 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-580734

RESUMO

Subcutaneous administration of bismuth, both single and multiple, resulted in deposition of this metal mainly in the kidneys which contained over 50% of the 'accessible pool' of bismuth. In the kidneys bismuth was bound mainly by the soluble fraction in which it was complexed with a protein of molecular weight of about 7000. Multiple administration of bismuth increased the level of this protein. Selenite administration brought about an increase in the 'accessible pool' of bismuth, probably due to a drop in excretion, and also changes in the organ distribution of this metal. The retention in the kidneys was diminished while those in the liver and in other tissues were augmented. These changes were accompanied by a change in the chemical form of bismuth present in the kidneys manifested by the total disappearance of the protein complex of molecular weight of 7000. The increased synthesis of this protein due to bismuth administration was not abolished completely.


Assuntos
Bismuto/metabolismo , Selênio/farmacologia , Animais , Feminino , Rim/metabolismo , Rim/ultraestrutura , Metalotioneína/metabolismo , Ligação Proteica , Radioisótopos , Ratos , Frações Subcelulares/metabolismo , Distribuição Tecidual/efeitos dos fármacos
18.
J Hyg (Lond) ; 69(3): 323-30, 1971 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-4937851

RESUMO

Strontium chloride B medium and E.E. broth have been found effective in the recovery of Edwardsiella, Salmonella and Arizona species from the cloacal contents of tiger snakes (Notechis scutatus). Strontium chloride B medium was superior to E.E. broth.At least one bacterial species was detected in each of the 60 reptiles examined, and all three organisms were recovered from each of 29 snakes on a single examination.Strontium chloride M, strontium selenite and Rappaport enrichment media and bismuth sulphite agar, although satisfactory for the isolation of Salmonella and Arizona species, were found unsuitable for Edwardsiella tarda.


Assuntos
Meios de Cultura , Enterobacteriaceae/isolamento & purificação , Klebsiella/isolamento & purificação , Salmonella/isolamento & purificação , Estrôncio/metabolismo , Animais , Técnicas Bacteriológicas , Bismuto/metabolismo , Cloretos/metabolismo , Cloaca/microbiologia , Selênio/metabolismo , Serpentes , Sulfitos/metabolismo
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