Study on growth characteristics of under different conditions and its toxicity / 南方医科大学学报

OBJECTIVE@#To investigate the characteristics of growth and metabolism and the toxicity of under different conditions.@*METHODS@#We observed the growth of and under routine culture conditions and in different pH and salt concentrations, and compared their activities of sugar fermentation using microbiochemical reaction tubes. Four-week-old nude mice were randomized into infection group (=5), infection group (=5) and control group (=5) for intragastric administration of 0.3 mL suspension the two (5×10 cfu/mL) or 0.3 mL normal saline. Samples of the liver, kidney, intestine, feces and blood were taken for analysis of the distribution and toxicity of by fungal culture and histopathological examination.@*RESULTS@# exhibited logarithmic growth at 8-24 h after inoculation and showed stable growth after 24 h. showed optimal growth within the pH value range of 5-7 with a growth pattern identical to that of . grew better than in media containing 5% and 10% NaCl, and could ferment glucose, sucrose, trehalose and sorbitol. could be isolated from the feces, blood, liver and kidney of infected nude mice, and the liver had the highest fungal load (5.7 log cfu/g). could cause pathological changes in the liver and intestine of the mice, but with a lesser severity as compared with .@*CONCLUSIONS@# exhibits optimal growth in mildly acidic or neutral conditions with a high salt tolerance, and can potentially penetrate the intestinal barrier into blood and lead to tissue injuries in hosts with immunosuppression.

Low dose and subchronic Aroclor 1254 induced histopathological changes in mice kidney

Present communication reports the low dose and subchronic duration-dependent histopathological changes afterexposure to Aroclor 1254 in the kidney tissue of Swiss albino mice. Polychlorinated biphenyls (PCBs) like Aroclor1254 congeners accumulate in tissues rich in lipids and remain inside for a long time, affecting the functionality of thecells in direct and indirect ways. The most commonly observed effects were skin ailments such as chloracne, rashes,and effects on kidney functions. Animal studies indicated that PCBs could affect the functionality of the kidney,thyroid, immune, and endocrine systems. Separate groups of mice were subjected to a daily oral dose of 0.1 mg/kgbody weight (BW)/day and 1 mg/kg BW/day Aroclor 1254, dissolved in corn oil, for four subacute exposure durations(7, 14, 21, and 28 days). Control groups were received only the corn oil (vehicle). Results revealed mainly exposureduration-dependent histopathological lesions such as dilation of the tubular cells, fragmentation of cytoplasm andloss of nuclear materials, formation of large vacuoles inside the cells, and necrosis even at very low doses of Aroclorintoxication. The present study reports predominantly exposure duration-dependent histopathological effects ofAroclor 1254 in the kidney tissue of mice. The study suggested that the subacute exposure to low doses of Aroclor1254 could cause significant irreparable structural deformities in the renal cells of the kidney tissue. Results alsoshowed that renal tubular cells were more affected showing severe necrosis

Carbon nanotubes:Evaluation of toxicity at biointerfaces / 药物分析学报

Carbon nanotubes (CNTs) are a class of carbon allotropes with interesting properties that make them productive materials for usage in various disciplines of nanotechnology such as in electronics equip-ments, optics and therapeutics. They exhibit distinguished properties viz., strength, and high electrical and heat conductivity. Their uniqueness can be attributed due to the bonding pattern present between the atoms which are very strong and also exhibit high extreme aspect ratios. CNTs are classified as single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) on the basis of number of sidewalls present and the way they are arranged spatially. Application of CNTs to improve the performance of many products, especially in healthcare, has led to an occupational and public exposure to these nanomaterials. Hence, it becomes a major concern to analyze the issues pertaining to the toxicity of CNTs and find the best suitable ways to counter those challenges. This review summarizes the toxicity issues of CNTs in vitro and in vivo in different organ systems (bio interphases) of the body that result in cellular toxicity.

Radioprotective effect of ultra-small carbon quantum dots in mice in vivo / 国际生物医学工程杂志

Objective To study the radioprotective effects of ultra-small carbon quantum dots (CQDs) in mice in vivo,and to reveal the protective mechanism,as well as to study the body immune response to CQDs and the toxicity in vivo.Methods Mice were injected with different concentrations of CQDs solution.Mice models of systemic radiation injury were constructed by high dose gamma rays radiation.The 30-days survival rate,bone marrow DNA,femoral bone marrow nucleated cells (BMNC),tissue superoxide dismutase (SOD) and malondialdehyde (MDA) were measured to evaluate the radioprotective effects of CQDs,and to investigate the possible protective mechanism.The toxicity of CQDs in vivo was studied by measuring the changes of body weight,liver index and spleen index before and after injections of CQDs in mice.Results CQDs showed obvious radioprotective effects on mice in vivo.Compared with the control group,the 30-days survival rate of irradiated mice treated with CQDs increased from 0％ to 40％.CQDs could effectively reduce the hematopoietic system damages caused by radiation,and increase the level of bone marrow DNA,femur BMNC,liver and lung SOD,as well as reduce the production of MDA in liver and lung.The results of immunological reaction tests showed that CQDs had less toxicity in vivo and did not trigger the body immune response.Conclusions CQDs has tremendous application prospects in the field of radiation protection.This study can provide new ideas for the application of new nano-materials in medical field.

Inhibition of coagulation proteases and thrombosis and sub-chronic toxicological study of a sulfated polysaccharidic fraction from the red alga Gelidiella acerosa / Inibição de proteases da coagulação e trombose e estudo toxicológico subcrônico de uma fração polissacarídica sulfatada da alga vermelha Gelidiella acerosa

Metabolites isolated from Gelidiella species (Rhodophyta) have been few studied. We evaluated a sulfated polysaccharidic fraction from G. acerosa collected from two Brazilian beaches on the northwestern coast of Brazil (Flecheiras-F and Pedra Rachada-PR) on coagulation proteases and thrombosis. Their toxicity in vivo was also assessed. Enzymatic extractions yielded 1.40%, and similar chromatographic profiles (DEAE-cellulose) were obtained, with fractions (Ga-I→V) containing differences among the relative proportions of sulfate (5-42%), and revealing charge density patterns by electrophoresis. Ga-IV-PR had a discrete effect (3.01 IU mg-1) on normal human coagulation compared with heparin (193 IU mg-1) and was tested on coagulation proteases (thrombin and factor Xa) in the presence of antithrombin and in a model of venous thrombosis in rats using thromboplastin as the thrombogenic stimulus. The systems were inhibited; but at higher doses (>1.0 mg kg-1), this fraction reverted the antithrombotic effect. Regarding the toxicological study, consecutive Ga-IV (9 mg kg-1) for 14 days did not cause mortality in mice, but some biochemical and hematological parameters were discretely altered. Histopathological analysis revealed that increased liver and spleen sizes had no toxicological significance. Therefore, G. acerosa does not biochemically change its matrix polysaccharide composition and proved to be safe antithrombotic agent.

Poucos estudos mostram metabólitos isolados de rodofíceas de espécies Gelidiella. Avaliou-se uma fração polissacarídica sulfatada de G. acerosa coletada a partir de duas praias brasileiras do Nordeste do Brasil (Flecheiras-F e Pedra Rachada-PR) sobre proteases da coagulação e trombose, e em ensaio de toxicidade in vivo. Extrações enzimáticas renderam 1,40% e foram obtidos perfis cromatográficos semelhantes (DEAE-celulose), apresentando frações (Ga-I→V), contendo diferenças entre as proporções relativas de sulfato (5-42%), além de a eletroforese revelar diferenças na densidade de carga. A Ga-IV-PR apresentou discreto efeito (3,01 UI mg-1) sobre a coagulação humana normal comparada à heparina (193 UI mg-1) e foi testada sobre proteases da coagulação (trombina e fator Xa) na presença de antitrombina e em um modelo de trombose venosa em ratos usando tromboplastina com estímulo trombogênico, sendo inibidos esses sistemas. Entretanto, em elevadas doses (>1,0 mg kg-1) o efeito antitrombótico foi revertido. No estudo toxicológico, Ga-IV (9 mg kg-1) consecutiva durante 14 dias não causou mortalidade em camundongos, mas alterou discretamente alguns parâmetros bioquímicos e hematológicos. O aumento nos tamanhos do fígado e baço não apresentou significância toxicológica, segunda análise histopatológica. Portanto, G. acerosa não muda bioquimicamente a composição de polissacarídeo de sua matriz e detém agente antitrombótico seguro.