Low scolicidal effect of Ocimum bacilicum and Allium cepa on protoccoleces of hydatid cyst: an in vitro study

Hydatidosis in humans and animals is an economic and public health treat in many parts of the world, and surgery is still the main treatment for hydatid disease. One of the most important endpoints of hydatid cyst surgery is recurrence. The main cause of recurrence is dissemination of protoscolices during the surgical operation. Preoperative destruction of the cyst’s contents through instillation of a scolicidal agent into the hydatid cyst is the most commonly used approach to prevent this complication. Various scolicidal agents have been used for inactivation of the cyst content, but most are accompanied by adverse side effects. In the present study, the scolicidal effect of methanolic extract of Ocimum bacilicum and Allium cepa is investigated. Protoscoleces were aseptically collected from sheep livers containing hydatid cyst and were used in the experiments. O. bacilicum and A. cepa extracts were used in 2.5, 5, and 10 % concentration for 10, 20, 30, 40, 50, and 60 min. Viability of protoscoleces was confirmed by 0.1 % eosin staining. The scolicidal effect of O. bacilicum and A. cepa extracts was not satisfactory and a 10 % concentration of these extracts after 60 min of application, killed only 24.1 and 16.8 % of protoscolices, respectively. Result of this study showed that, as opposed to the fact that these extracts have a strong antibacterial effect, they have low scolicidal activity and cannot be used as scolicidal agent; on the contrary of in vitro inefficacy, the in vivo efficacy of these extracts and also their possible side effects remained to be examined.     

High scolicidal effect of Zataria multiflora on protoccoleces of hydatid cyst: an in vitro study

Hydatidosis in humans and animals is an economic and public health problem in many parts of the world, and surgery is still the main treatment for hydatid disease. One of the most important endpoints of hydatid cyst surgery is recurrence. The main cause of recurrence is dissemination of protoscolices during the surgical operation. Preoperative destruction of the cyst’s contents through instillation of a scolicidal agent into the hydatid cyst is the most commonly used approach to prevent this complication. Various scolicidal agents have been used for inactivation of the cyst content, but most are accompanied by adverse side effects. In the present study, the scolicidal effect of methanolic extract of Zataria multiflora is investigated. Protoscoleces were aseptically collected from sheep livers containing hydatid cyst and were used in the experiments. Z. multiflora extract was used at a concentration of 10 and 25 mg/ml for 1, 2, and 3 min. Viability of protoscoleces was confirmed by 0.1% eosin staining. Z. multiflora extract at a concentration of 10 mg/ml killed 68.9%, 93.7%, and 100% of protoccoleces after 1, 2, and 3 min respectively. The scolicidal effect of this extract at a concentration of 25 mg/ml was 100% after 1 min. The results of present study showed that methanolic extract of Z. multiflora has high scolicidal activity and might be used as an effective scolicidal agent. This is the first report on the scolicidal activity of Z. multiflora.     

Effect of octenidine dihydrochloride on viability of protoscoleces in hepatic and pulmonary hydatid diseases

BACKGROUND: Use of effective scolicidal agents during puncture, aspiration or injection of a scolicidal agent and reaspiration (PAIR) and surgery for hydatid cysts are essential to reduce the recurrence rate. In this in vitro study, we tried to determine the scolicidal property of a new agent, octenidine dihydrochloride, and of various agents in different concentrations and exposure times. MATERIAL AND METHODS: Echinococcus granulosus protoscoleces were obtained from six patients with liver (n=3) and lung (n=3) hydatid cysts. Various concentrations of octenidine dihydrochloride (0.1%, 0.01% and 0.001% diluted form), povidone iodine (10%, 1% and 0.1% diluted) and 20% saline were used in this study. Viability of protoscoleces was determined with dye-uptake (0.1% eosin) and flame cell activity. RESULTS: Octenidine dihydrochloride 0.1% had strong scolicidal effect in 15 min and octenidine dihydrochloride 0.01% in 30 min. Sixty percent of protoscoleces lost viability at 5 min with octenidine dihydrochloride 0.1%. Viability ratio decreased to 20% at 10 min, and all of them died at 15 min. Povidone iodine 10% and 1% had strong scolicidal effects after 15- and 30 min of exposure, respectively. Saline 20% killed all the protoscoleces in 30-min exposure. CONCLUSION: Because of the rapid and strong scolocidal effectiveness of octenidine dihydrochloride on protoscoleces, it may be used as a scolocidal agent during both perioperative and in the PAIR method.     

Scolicidal effectiveness of essential oil from Zataria multiflora and Ferula assafoetida: disparity between phenolic monoterpenes and disulphide compounds

Hydatidosis in humans and animals is a substantial cause of deaths in many parts of the world. Surgery and the chemotherapeutic agents are the main treatments for hydatid disease; however, most of them are accompanied by adverse side effects. In this study, the scolicidal effect of essential oils from Zataria multiflora and Ferula assafoetida against Echinococcus granulosus protoscolices was investigated. Essential oils from Z. multiflora and F. assafoetida were prepared by hydrodistillation and analyzed by gas chromatography–mass spectrometry. Carvacrol (29.2 %), thymol (25.4 %), p-cymene (11.2 %), linalool (9.6 %), and γ-terpinene (8 %) were detected as the main components of the Z. multiflora, while the main components of F. assafoetida were E-1-propenyl-sec-butyl disulfide (62.7 %), β-ocimene (21.7 %) and β-pinene (5 %). Scolicidal activities of the essential oils against protoscolices for Z. multiflora and F. assafoetida were obtained at concentrations more than 17 and 60 μg/mL, respectively. Accordingly, it was concluded that both essential oils can selectively reduce protoscolices viability, and Z. multiflora, which contains phenolic monoterpenes, is more cytotoxic rather than F. assafoetida which contains disulfide compounds. Therefore, Z. multiflora and F. assafoetida could be recommended as a treatment against hydatid cyst.     

The damages of high intensity focused ultrasound to transplanted hydatid cysts in abdominal cavities of rabbits with aids of ultrasound contrast agent and superabsorbent polymer

The present study investigates the damages of high intensity focused ultrasound (HIFU) to transplanted hydatid cysts in abdominal cavities of rabbits with aids of ultrasound contrast agent (UCA) and superabsorbent polymer (SAP) alone or in combination. A rabbit model with transplanted hydatid cyst was established by implanting hydatid cyst isolated from infected sheep liver, and HIFU was used to ablate the transplanted cysts with the aid of UCA and SAP alone or in combination. The hydatid cyst with thin wall, good elasticity, approximately spherical, and a diameter of approximately 30 mm was selected for the following experiments. According to our previous studies, a mixture of 0.1 g SAP and 0.5 ml anhydrous ethanol, and the solution of 0.1 ml UCA SonoVue, or both materials were injected into different cyst before HIFU ablation, respectively. The cyst inoculated with the SAP and UCA alone or in combination was immediately implanted into the abdominal cavity of rabbit for HIFU ablation at a dosage of 100 W acoustic powers. The ablation mode was spot scanning at the speed of 3 mm/s. Every target point was scanned three times; every ablating time lasted 3 s. The distance of each ablated layer was 5 mm. The total ablation time depended on the volume of cyst. The comparison of ultrasound image for each layer of hydatid cyst was made before and after HIFU ablation. The protoscolices in ablated cysts were stained by trypan blue exclusion assay, and their structures were observed by light microscopy. To estimate ablation effects of HIFU to the walls of hydatid cysts, the ultrastructure changes of cyst walls were examined by electron microscopy. The pathological changes of rabbits’ skins through which ultrasound penetrated were observed to investigate the side effects of HIFU ablation. The results demonstrated that HIFU had some lethal effects to hydatid cysts in vivo, namely, echo enhancements of ultrasound images of cysts, increases in mortality rate of protoscolices from 15.19 % (HIFU alone) to 48.66 % (HIFU?+?SAP), 38.67 % (HIFU?+?UCA), and 67.75 % (HIFU?+?SAP?+?UCA), respectively, serious structural damages of protoscolices, and destructions or even disappearance of laminated layers and germinal layers in the walls of hydatid cysts ablated by HIFU aided with UCA and SAP alone or in combination. This study demonstrated that destructive effects of HIFU to transplanted hydatid cyst could be enhanced by UCA and SAP alone, but the destruction of HIFU aided with a combination of UCA and SAP to hydatid cysts was more effective than those aided with UCA or SAP alone. The enhanced thermal and cavitation effects of HIFU induced by UCA and SAP might be involved in the enhanced destructive effects of HIFU on hydatid cysts. There were no evidences of pathological changes on rabbits’ skins overlying the hydatid cysts after HIFU ablation. The results suggested that the rabbit model with transplanted hydatid cyst may serve as an optional animal model for the experiments of HIFU ablation to hydatid cyst in vivo, and the materials of UCA and SAP were proved as enhancing agents of HIFU ablation to hydatid cysts, and HIFU at a dosage of 100 W acoustic powers was a safe and feasible parameter to ablate the hydatid cysts in this special animal model. These results laid a theoretical foundation for improving HIFU therapy for cystic echinococcosis by inoculation of UCA and SAP into hydatid cysts.     

细粒棘球绦虫重组Bb—Eg95-EgA31疫苗诱导小鼠脾细胞增殖变化的研究

目的探讨细粒棘球绦虫（Eg）重组双歧杆菌（Bb）-Eg95-EgA31疫苗免疫和Eg原头节攻击后小鼠的囊重抑制率及脾细胞增殖的变化。方法将细粒棘球绦虫重组Bb-Eg95-EgA31疫苗分别采用皮下注射、肌肉注射、鼻腔内接种和口服灌胃4种途径免疫BALB／c小鼠,免疫后8周每鼠用50个Eg原头节攻击感染,感染后25周剖杀小鼠,分离细粒棘球蚴包囊并称重,计算囊重抑制率;取脾,分离脾细胞,用Eg粗抗原（EgAg）或刀豆素A（ConA）刺激培养,四甲基偶氮唑盐比色法（MTT法）检测免疫小鼠脾细胞增殖反应,同时设有空载体、Bb和MRS对照。结果以上4种疫苗接种组小鼠的囊重抑制率分别为45．33％、41．33％、70．67％和62．67％;疫苗接种组的脾细胞明显增殖;鼻腔内接种和口服免疫组的脾细胞增殖显著高于皮下和肌肉注射组。结论细粒棘球绦虫重组Bb-Eg95-EgA31疫苗可诱导小鼠产生特异性的细胞免疫反应。     

Echinococcus granulosus: occurrence of ecdysteroids in protoscoleces and hydatid cyst fluid

Both free ecdysteroids and hydrolysable polar conjugated ecdysteroids were detected in protoscoleces of Echinococcus granulosus from the equine host, and in hydatid cyst fluid from the same source. Comparisons were made of hydatid cyst fluid from E. granulosus infections of three intermediate host species: horses, sheep and humans. Ecdysone and 20-hydroxyecdysone were identified in both protoscoleces and hydatid cyst fluids by high-performance liquid chromatography monitoring fractions by radioimmunoassay, and by capillary gas chromatography/mass spectrometry (selected ion monitoring). The free ecdysteroid fractions of hydatid cyst fluid from horses and sheep also contained several unidentified, chromatographically unique, immunoreactive compounds which were refractory to hydrolysis with a crude Helix pomatia aryl sulphatase enzyme preparation.     

Hydatidosis: prevalence and biometrical studies in sheep in Kerman area, southeast of Iran

A cross-sectional survey was carried out on the sheep slaughtered at the Kerman abattoir from September 2010 to September 2011 to determine the prevalence of cystic hydatidosis. Postmortem examinations on hydatid cyst characterization were conducted. Out of the total of 1,643 animals examined (659 females and 984 males), 165 (10.04 %) were found harboring one or more hydatid cyst. The result obtained from postmortem examinations indicated that a total of 246 visceral organs were found harboring one or more hydatid cysts. The involvement of lung, liver, muscles, and kidney was found to be 49.59, 47.96, 1.21, and 1.21 %, respectively. From the total of 2,129 cysts counted, 875 (41.09 %), 720 (33.81 %), 258 (12.11 %) and 276 (12.96 %) were small, medium, large, and calcified cysts respectively, and 1,083 (50.86 %) and 770 (36.16 %) were fertile and sterile cysts respectively. Out of the 1,083 fertile cysts subjected for viability test, 899 (83.01 %) were viable. In conclusion, these findings of infections, meaning abundance and fertility rates of cystic echinococcosis in sheep slaughtered, prompt plans for further epidemiological studies and controlling programs.     

Mycobactericidal activity of glutaraldehyde solutions.

Aqueous solutions of alkaline glutaraldehyde (buffered at pH 8.5) inactivated a standard suspension of Mycobacterium tuberculosis H37Rv faster than the corresponding acid (pH 3.7 preparation. Quantitative differences in the rate of inactivation of eight other species of Mycobacterium were determined using a 1% solution of alkaline glutaraldehyde and inactivation of residual glutaraldehyde with 1% sodium bisulfite solution. Variations in the rate of kill were observed between the various mycobacterial species tested, but such differences were probably not sufficiently large to be of practical importance. A 2% alkaline glutaraldehyde solution inactivated 10(5) viable M. tuberculosis cells present on the surface of porcelain penicylinders within 5 min at 18 degrees C. This rate of inactivation was faster than in the acidic solution.     

The destructive effects of high-intensity focused ultrasound on hydatid cysts enhanced by ultrasound contrast agent and superabsorbent polymer alone or in combination

Cystic echinococcosis, caused by the metacestode stage of Echincoccus granulosus, remains endemic in many regions around the world. The present work evaluated whether or not a superabsorbent polymer (SAP) and ultrasound contrast agent (UCA) alone or in combination could enhance damage efficacy of high-intensity focused ultrasound (HIFU) on hydatid cysts in vitro. HIFU of 100 W acoustic power, with the aid of 0.1 ml UCA and 0.1 g SAP alone or in combination, was used to ablate hydatid cysts in vitro. The comparison of ultrasound image for each layer of hydatid cyst before and after HIFU ablation was made immediately, and the protoscolices of the cysts were stained by eosin exclusion assay, and the structures of protoscolices were observed by light microscopy. To understand the destructive effects of HIFU, the pathological changes in cyst walls of hydatid cyst ablated with HIFU were examined. The results demonstrated that HIFU had some lethal effect on hydatid cysts: echo enhancement of ultrasound image, increase of mortality rate of protoscolices, serious structural damage of protoscolices, and complete destruction or even disappearance of laminated layer and germinal layer was observed in the group of HIFU combined with UCA and SAP alone or in combination. It was found that the destructive effect of HIFU aided with a combination of UCA and SAP to hydatid cysts was more effective than that of HIFU just aided with UCA or SAP alone. These results suggested that UCA and SAP might be used as a HIFU enhancing agent to improve the efficacy of HIFU ablation to hydatid cysts, which could be a possible therapeutic option for cystic echinococcosis.     

细粒棘球绦虫转Eg95-EgA31融合基因苜蓿疫苗诱导的保护力观察

目的探讨细粒棘球绦虫（Eg）转Eg95-EgA31融合基因苜蓿疫苗免疫BALB/c小鼠后对Eg原头节攻击感染的保护性作用。方法热絮凝法提取转基因苜蓿的叶蛋白,配成浓度为20μg/μl。分别用100μl（约含1μg融合抗原）口服灌胃和10μl（约含0.1μg融合抗原）滴鼻接种免疫BALB/c小鼠,每3d免疫1次,连续免疫2月,同时设转空质粒（pBI121）苜蓿叶蛋白及正常苜蓿叶蛋白对照组。末次免疫后8周,用Eg原头节进行攻击感染（腹腔注射50个Eg原头节/每只小鼠）,感染后24周剖杀各组小鼠,检获包囊质量,计算囊重减少率;采眼球血,常规酶联免疫吸附试验法（enzyme-linked immunosorbent assay,ELISA）检测血清中IgG及其亚类和IgE水平。结果疫苗口服灌胃接种组小鼠检获包囊质量明显降低,囊重减少率为64.1%,与正常蛋白对照组相比,差异有统计学意义（P〈0.05）,血清中IgG、IgG2b和IgE水平显著高于正常苜蓿叶蛋白对照组,其值分别为0.175±0.013、0.096±0.028和0.096±0.028。结论细粒棘球绦虫转Eg95-EgA31融合基因苜蓿疫苗口服接种能使免疫鼠获得保护力以抵抗Eg原头节攻击感染,IgG、IgG2b和IgE在疫苗诱导的保护力中起重要作用。     

Acid Exposure Induces Multiplication of Salmonella enterica Serovar Typhi

Salmonella enterica serovar Typhi faces several environmental stresses while going through the stomach (acidic pH) to the small intestine (basic pH) and intracellularly in macrophages (acidic pH) in humans. The acidic pH followed by alkaline pH in the small intestine might be responsible for expression of certain stress-induced genes, resulting in not only better survival but also induction of multiplication and invasion of the bacterium in the small intestine. Based on this hypothesis, we developed a process wherein we exposed the blood, urine, and stool specimens from 90 acute typhoid fever patients and 36 chronic typhoid carriers to acidic pH to see the effect on isolation rate of S. Typhi. About 5 g of freshly passed unpreserved stool, a centrifuged deposit of 15 ml of urine, and 5 ml of blood clot were subjected to 5 ml of Luria-Bertani (LB) broth (pH 3.5) for 20 min, followed by enrichment in bile broth-selenite F broth. When the combined isolation from all 3 specimens, i.e., blood, urine, and stool, after acid exposure was considered, a total of 77.7% of the acute typhoid patients were observed to be positive for the isolation of the S. Typhi serotype, compared to 8.8% by the conventional method. Similarly, 42% (15/36) of chronic carriers yielded positive for S. Typhi growth after acid exposure, compared to 5.5% (2/36) by the conventional method. It therefore can be concluded that acid shock triggers the multiplication of the bacteria, resulting in better isolation rates from blood clot, stool, and urine specimens.     

Humoral and cytokine response during protection of mice against secondary hydatidosis caused by Echinococcus granulosus

Infection of BALB/c mouse with protoscoleces of Echinococcus granulosus constitutes a model for the study of secondary hydatidosis and the associated immune response in immunization and infection trials. The aims of this study were to induce a protective immunity against secondary hydatidosis using conventional vaccination approaches and to analyse the immune responses that accompany this protection. Mice immunized with antigen B (AgB), a component of crude sheep hydatid fluid (CSHF), showed a significant level of protection as indicated by a 98.3% reduction in cyst load. This reduction in cyst development was accompanied by a high concentration of interferon gamma secreted by antigen-stimulated spleen cells, as compared with those secreted by cells of mice immunized with CSHF or protoscoleces homogenate (PSH) antigens. In contrast, interleukin-4 was significantly higher in the supernatants of cells stimulated with CSHF or PSH compared with AgB (191.5, 195.7 and 127.5 pg, respectively). Kinetic analysis of immunoglobulin subclasses showed persistently high levels of IgG1 and IgG2a subclasses in immunized infected animals until 6 months of infection, whereas IgG3 showed a significant decline after 1 month of infection. In infected non-immunized control mice, all IgG subclasses showed a gradual increase after the first month of infection until the experiment termination (8 months after infection).     

The phylogenetic similarity of hydatid cyst isolated from humans and sheep in Ilam Province southwest of Iran

Hydatid cyst is a chronic zoonotic disease caused by the larval stage of the dog tapeworm, Echinococcus granulosus. To identify genotype of hydatid cysts of human and sheep jackal in Ilam Province (South West of Iran), the PCR-RFLP and DNA sequencing were used. A total of 10 human and 20 sheep protoscoleces hydatid cyst samples were collected from different hospitals and slaughterhouses. Then, the gene of cox1 of mitDNA of the parasite was amplified and PCR products were cut using AluI and HpaII restriction enzymes. Finally, a number of PCR products were bi-directionally sequenced. Based on the DNA sequencing and PCR-RFLP results, human and sheep samples indicated to pertain the genotypic similarities. Our data indicated that, the genotypes of larval stage of E. granulosus is similar in both intermediate hosts. According to the phylogenetic tree, there is at least one genotype of parasite, which belongs to E. granulosous sensu stricto (G1–G3) complex and overall isolates sequences of mtDNA indicated 100 % homology with references G1, G2, and G3 sequences in the GenBank database. G1 genotype was the dominant genotype of human and livestock.     

Alterations of ventricular pH alter water intake and food consumption in rats

The pH of third ventricular CSF was altered by infusing acidic or alkaline solution of artificial cerebrospinal fluid (aCSF) through chronically implanted stainless steel cannula. In two separate group of rats (n = 18 each) water and food consumptions were recorded 30 min, 1 hr, and 24 hr after intraventricular infusions of the modified aCSF solutions having pH 6.0, 8.0 and 7.4 (control). On raising the CSF pH, water intake increased in all three observations. Feeding was not affected in the observations taken after 30 min and 1 hr, but significantly reduced food consumption was observed 24 hr after the infusions. Lowering of pH had no effect either on dipsogenic or feeding response. The CSF pH correlated positively with drinking in all three observations. Since dipsogenic and feeding responses are centrally regulated by ion sensitive cells, it may be presumed that altered CSF pH influenced the activities of the sensors by altering ionic conductance across their membranes.     

<Emphasis Type="Italic">In vitro</Emphasis> clearance of doxorubicin with a DNA-based filtration device designed for intravascular use with intra-arterial chemotherapy

To report a novel method using immobilized DNA within mesh to sequester drugs that have intrinsic DNA binding characteristics directly from flowing blood. DNA binding experiments were carried out in vitro with doxorubicin in saline (PBS solution), porcine serum, and porcine blood. Genomic DNA was used to identify the concentration of DNA that shows optimum binding clearance of doxorubicin from solution. Doxorubicin binding kinetics by DNA enclosed within porous mesh bags was evaluated. Flow model simulating blood flow in the inferior vena cava was used to determine in vitro binding kinetics between doxorubicin and DNA. The kinetics of doxorubicin binding to free DNA is dose-dependent and rapid, with 82–96 % decrease in drug concentration from physiologic solutions within 1 min of reaction time. DNA demonstrates faster binding kinetics by doxorubicin as compared to polystyrene resins that use an ion exchange mechanism. DNA contained within mesh yields an approximately 70 % decrease in doxorubicin concentration from solution within 5 min. In the IVC flow model, there is a 70 % drop in doxorubicin concentration at 60 min. A DNA-containing ChemoFilter device can rapidly clear clinical doses of doxorubicin from a flow model in simple and complex physiological solutions, thereby suggesting a novel approach to reduce the toxicity of DNA-binding drugs.     

Functional expression of the oligopeptide transporter PepT1 from the sea bass (Dicentrarchus labrax)

Complementary RNA, derived from the intestine of the sea bass Dicentrarchus labrax and putatively coding for a pH-dependent oligopeptide transporter PepT1 (SLC15 family), was injected in Xenopus oocytes that were subsequently tested with electrophysiological techniques. Transport-associated currents were observed when various di- or tripeptides were applied at concentrations ranging between 0.1 and 10 mM. No currents were generated by histidine nor by other single amino acids. Sea bass PepT1 also exhibited presteady-state currents in the absence of substrates. Acidic pH slowed down the relaxation time constant of these currents and shifted both Q/V and τ/V relationships toward more positive voltages. Michaelis–Menten analysis of the transport currents showed an increase in apparent substrate affinity at acidic pH, which was very similar to that exhibited by the related transporter from zebrafish (Danio rerio), but in contrast, did not demonstrate a significant effect of pH on the maximal transport current.     

Primary hydatid cyst of the supraspinatus muscle: Complete removal of the germinal layer and cytodiagnosis by fine‐needle aspiration

Primary hydatid disease of the skeletal muscle without systemic involvement is rare. The purpose of this report is to document the novel clinical presentation and the interesting facets of fine‐needle aspiration in a case of hydatid disease. It was a case of primary hydatid cyst of the left supraspinatus muscle in an Indian woman living in Kuwait, which was clinically diagnosed as a lipoma. Fine‐needle aspiration (FNA) yielded 2 ml of clear fluid with white particulate material. The cytocentrifuged smears prepared from the aspirated fluid showed many scolices, occasional laminated cyst wall fragments and numerous hooklets. The laminated cyst wall and scolices were PAS positive. Trichrome staining imparted a demon‐head‐like appearance to the scolices. The cytodiagnosis of hydatid cyst was corroborated by histopathological examination of an excised whitish membrane and an irregular cystic fragment, which showed parallel laminations without germinal layer, and skeletal muscle with granulomas and a dense eosinophilic infiltration, respectively. Quantitative serological (indirect hemagglutination) test on blood sample collected 9 days after the excision of the cyst showed insignificant antibody titer to Echinococcus sp. and after 6 weeks the antibodies were completely absent. CT scan of the chest and abdomen performed 7 weeks after removal of cyst showed no evidence of visceral hydatid cyst. Diagn. Cytopathol. 2014;42:268–272. © 2012 Wiley Periodicals, Inc.     

Acidic priming enhances metastatic potential of cancer cells

Metabolic acidosis is a common feature of tumor microenvironment and may affect the phenotype of tumor cells, including invasive capacity and formation of metastases. We tested whether previous exposure to an acidic environment alters metastatic potential of two rat carcinoma cell lines in the animal model. In addition, we determined the effect of an acidic environment on motility and invasive capacity of AT-1 prostate carcinoma cells in culture. Exposure of tumor cells to an acidic environment (pH 6.6, 5 % CO₂, 6 h) prior to tail vein injection in rats enhanced formation of lung metastases significantly. In culture, acidosis increased cellular motility of AT-1 cells. When the tumor cells were transferred back to pH 7.4, enhanced motility persisted for at least 3 h but vanished after longer periods (24 h), therefore presenting a “short-term memory effect.” Although acidosis augmented phosphorylation of ERK1/2 and p38, and inhibition of ERK1/2 phosphorylation or of p38 kinase activity reduced basal motility at pH 7.4, acidosis-induced increase in motility was not dependent on ERK1/2 or p38 kinase. Src family kinases were not involved either. By contrast, scavenging reactive oxygen species (ROS), known to be increased in AT-1 cells under acidic conditions, blunted acidosis-induced motility increase. Our data indicate that tumor cells may acquire enhanced motility in an acidic micromilieu, at least in part due to enhanced ROS formation. Because enhanced motility persists for at least 3 h after leaving the acidic environment, this may promote metastasis formation, as observed in our in vivo model.     

Preparation and characterization of polyelectrolyte complex nanoparticles based on poly (malic acid), chitosan. A pH-dependent delivery system

The main objective of this work was to develop polyelectrolyte complex (PEC) nanoparticles based on poly (malic acid), chitosan (PMLA/CS) as pH-dependent delivery systems. The results indicated that the PMLA/CS Nps were successfully prepared. The prepared PMLA/CS Nps showed spherical morphology with a mean diameter of 212.81 nm and negative surface charge of ?24.60 mV, and revealing significant pH-sensitive properties as the mass ratio of PMLA to CS was 5:5. The prepared PMLA/CS Nps were characterized by FT-IR, TEM and DLS. The prepared PMLA/CS Nps remained stable over a temperature range of 4–53 °C. Doxorubicin (Dox) as a model drug was loaded on the nanoparticles through the physical adsorption method. The high drug loading efficiency (16.9%) and the sustained release patterns in acidic media were observed, and the release accelerated in alkaline solutions. MTT based cytotoxic analysis also depicted the non-toxic nature of PMLA/CS Nps, while Dox-PMLA/CS Nps showed dose-dependent cytotoxicity towards MDA-MB-231 cells. Hence, the nanoparticles could be potentially applied as pH sensitive drug vehicles for controlled release.