The evaluation of a semiautomated computer method to determine the effects of DMSO on Giardia lamblia-intestinal cell interaction.

In this work, we describe a semiautomated computer method to evaluate the activity of a common drug solvent, dimethyl sulfoxide (DMSO), on in vitro Giardia lamblia-host cell interaction. To compare the number of intestinal cells (IEC-6) and the adhered trophozoites over a specific area in control and treated coculture, a computer routine was created. Using video-light microscopy and digital image-processing tools, the operator was able to count the number of epithelial cells or parasites when they were still lying on the slide surface and without the need to detach them from the substrate for counting with a hemocytometer or other counting devices. Using this strategy, we calculated the total cell number per area and verified the effects of different concentrations of DMSO on G. lamblia-intestinal cell interaction and on the IEC-6 culture. At concentrations of 0.2% and 1%, this solvent produced a fragmentation on the monolayer of epithelial cells. However, DMSO did not affect the attachment of G. lamblia. In the course of these experiments, we compared the semiautomated method to the manual counting method and found that the first one generated smaller standard deviations (SD) than the second.

Giardia lamblia: the effects of extracts and fractions from Mentha x piperita Lin. (Lamiaceae) on trophozoites.

Giardia lamblia is a parasite that causes giardiasis in humans and other mammals. The common treatment includes different classes of drugs, which were described to produce unpleasant side effects. Mentha x piperita, popularly known as peppermint, is a plant that is frequently used in the popular medicine to treat gastrointestinal symptoms. We examined the effects of crude extracts and fractions from peppermint against G. lamblia (ATCC 30888) on the basis of trophozoite growth, morphology and adherence studies. The methanolic, dichloromethane and hexanic extracts presented IC(50) values of 0.8, 2.5 and 9.0microg/ml after 48h of incubation, respectively. The aqueous extract showed no effect against the trophozoites with an IC(50)>100microg/ml. The aqueous fraction presented a moderate activity with an IC(50) of 45.5microg/ml. The dichloromethane fraction showed the best antigiardial activity, with an IC(50) of 0.75microg/ml after 48h of incubation. The morphological and adhesion assays showed that this fraction caused several alterations on plasma membrane surface of the parasite and inhibited the adhesion of G. lamblia trophozoites. Cytotoxic assays showed that Mentha x piperita presented no toxic effects on the intestinal cell line IEC-6. Our results demonstrated antigiardial activity of Mentha x piperita, indicating its potential value as therapeutic agent against G. lamblia infections.

Susceptibility of Giardia lamblia to Hovenia dulcis extracts.

Giardia lamblia is the causative agent of giardiasis, a common parasitic infection of the human and animal digestive tract. Although several drugs have been available to treat this infection, they present unpleasant side effects or cytotoxicity. In order to find a more natural treatment for the disease, we analyzed the effects of the methanolic extract and three fractions obtained from Hovenia dulcis Thunb. (Rhamnaceae) leaves on G. lamblia. Comparing all fractions, dichloromethane was more efficient in reducing Giardia growth. The exposition of G. lamblia to this fraction lead to degenerations in the surface, modifications in the cell shape and alterations in the localization of nuclei. Besides that, the adhesion of G. lamblia was also altered. Experiments revealed that the obtained fraction did not present cytotoxic effects in mammalian cells. In summary, dichloromethane fraction has strong antigiardial effects and could become an important new substance for the treatment of giardiasis.

Electron and video-light microscopy analysis of the in vitro effects of pyrantel pamoate on Giardia lamblia.

Electron and video-light microscopy analysis of the in vitro effects of pyrantel pamoate on Giardia lamblia. Experimental Parasitology 97, 9-14. Giardia infection is predominant in the small intestine of vertebrates, where the trophozoites attach to epithelial cells and adversely affect the microvilli and other epithelial cell structures. Giardiasis, the disease caused by this protozoan, is very common in developing countries and mainly affects children. Drugs currently used to treat Giardia infection, such as some benzimidazole derivatives, were originally designed to treat helminthic infections. Many of the drugs are known to cause severe side effects and disturbances to the patient. Using transmission electron microscopy and video-light microscopy, we studied the effects of pyrantel pamoate, a drug commonly used in the treatment of helminthic infections in horses and ruminants, on Giardia lamblia trophozoites. Pyrantel pamoate was administered to Giardia cells in four different concentrations. Using video-light microscopy, we observed the decrease in flagella beating frequency and severe changes in the lateral flange and in the general aspect of the cell. Using transmission electron microscopy, we observed changes in the cytoplasm and peripheral vesicles. The flagella and adhesive disk structure were not affected. Apparently, the effects of pyrantel pamoate are irreversible.

Correlation of p53 status with outcome of neoadjuvant chemotherapy using paclitaxel and doxorubicin in stage IIIB breast cancer.

BACKGROUND: The role of p53 in modulating apoptosis has suggested that it may affect efficacy of anticancer agents. We prospectively evaluated p53 alterations in 73 patients with locally advanced breast cancer (IIIB) submitted to neoadjuvant chemotherapy. PATIENTS AND METHODS: Patients received three cycles of paclitaxel (175 mg/m2) and doxorubicin (60 mg/m2) every 21 days. Tumor sections were analyzed before treatment for altered patterns of p53 expression using immunohistochemistry and DNA sequencing. RESULTS: An overall response rate of 83.5% was obtained, including 15.1% complete pathological responses. The regimen was well tolerated with 17.7% grade 2/3 nausea and 12.8% grade 3/4 leukopenia. There was a statistically significant correlation between response and expression of p53. Of the 25 patients who obtained a complete clinical response, two were classified as positive (P = 0.004, chi-square). Of 11 patients who obtained a complete pathological remission, one was positive (P = 0.099, chi-square). Discussion The combination is highly effective in locally advanced breast cancer. A negative expression of p53 indicates a higher chance of responding to this regimen. The p53 status may be used as a biological marker to identify those patients who would benefit from more aggressive treatments.