Background: Giardiasis is the most common infectious diseases of medical parasitology and public health in our country and in many countries is important. Accourding the importance of treating the disease, particularly parasite resistance to drugs. Thus, the aim of present study was investigated the effect of gold nanoparticles on Giardia lamblia cyst stage of the in vitro.

Materials and Methods: In this experimental study, Giardia cysts from contaminated fresh feces were collected and concentrated with use 0.85 M sucrose methods for isolation of cysts. Samples after counting with Noubar slide were stored at 4°C. The gold nanoparticles at concentrations of 0.05, 0.1, 0.3 mg/ml prepared and verified, the particle size was determined. The effect of different concentrations of the nanoparticles at 5, 15, 30, 60 and 180 minutes was evaluated and compared to control groups (metronidazole). Data from the study were recorded and analyzed with T-test and Chi-square by used SPSS software.

Results: The results of the cytotoxic effect of nanoparticles on the different concentration and time of Giardia lamblia cysts in vitro compared with the positive control (Metronidazole) shows mean percent of effect gold nanoparticles increased with increasing concentration and exposure time, so that the concentration of 0.3 mg/ml from 62% at 5 min to 96% at 180 min increased (p<0.05). Also, the survey results show Giardia cysts with increasing exposure time , killing effect of gold nanoparticles at a concentration of 78% in 0.05 mg/ml to 96% at a concentration of 0.3 mg/ml greatest increased (p<0.05). As a result, the concentration of gold nanoparticles in comparison with Metronidazole has the most effect gold nanoparticles at a concentration of 0.3 mg/mL, almost the same effect of Metronidazole as the drug of choice in the treatment of Giardia lamblia.

Conclusion: Therefore, the results of this study, gold nanoparticles at a concentration of 0.3 mg/ml as an effective combination for killing Giardia lamblia cysts in vitro can be used. Thus, future studies on laboratory animals (In vivo) are recommended.

Background: Occult hepatitis C virus (HCV) infection is defined as the presence of HCV-RNA in liver or peripheral blood mononuclear cells (PBMCs) in the absence of detectable hepatitis C antibody (anti-HCV) or HCV-RNA in the serum. Although occult HCV infection is less aggressive than classic chronic HCV infection, nevertheless it is important in management of hemodialysis (HD) patients. Occult HCV infection has been described in two different clinical settings: in patients with normal liver enzymes or in patients with abnormal values of liver enzymes. The aim of this study was to detect the occult HCV infection in hemodialysis patients with elevated liver enzymes.

Materials and Methods: This cross sectional study was performed in hemodialysis patients referring to 3 dialysis units in Tehran. In 30 anti-HCV negative HD patients with elevated liver enzymes, presence of HCV-RNA in plasma samples was tested by Reverse Transcriptase-Nested Polymerase Chain Reaction (RT-nested PCR). In cases with negative anti-HCV and plasma HCV-RNA, HCV-RNA was checked in PBMC specimens by RT-nested PCR.

Results: A total of 30 HD patients with mean age 54.4± 14.1years and mean dialysis duration 81.2 ±64.4 months were enrolled in the study. All HD subjects were negative for HCV-RNA in plasma and occult HCV infection with RT-nested PCR method.

Conclusion: Occult HCV infection was rare in HD patients with elevated levels of liver enzymes.