[Extraction Method of Malaria Parasite DNA from Preserved Positive Blood Smears].

OBJECTIVE: To develop a method for DNA extraction from malaria parasites on preserved blood smears, to provide basis for research on malaria genetic traceability. METHODS: The improved DNA extraction kit (QIAamp DNA Mini Kit) was used to extract plasmodium DNA from 41 giemsa-stained blood smears, and the extraction was compared with that using the Chelex-100 and Na(2)HPO(4) methods. Nested PCR was used to amplify small subunit ribosomal RNA to identify Plasmodium parasite. The PCR products underwent sequencing and sequence alignment, to analyze the difference in PCR positive rates between blood smears prepared in the 1980s and in recent 10 years, between blood smears with and without deoil/decoloration, and between blood smears with different qualities. RESULTS: The total PCR positive rate for the improved kit method was 70.7% (29/41). The PCR positive rate for blood smears prepared in the 1980s and in recent 10 years was 78.6% (11/14) and 66.7% (18/27) respectively, with no significant difference (W=0.63, P>0.05). The PCR positive rate for blood smears with and with- out deoil/decoloration was 62.5% (15/24) and 82.4% (14/17) respectively, also with no significant difference (χ(2)= 1.89, P>0.05). However, the PCR positive rate was significantly higher in blood smears with high quality [93.3% (28/30)] than those with low quality [9.1%(1/1l)](=27.59, P<0.01). Sequence alignment showed that the PCR products were consistent with the target DNA fragments. However, DNA extracted using the Chelex-100 and Na(2)HPO(4) methods showed negative PCR results. CONCLUSIONS: DNA extracted from blood smears prepared in the 1980s using the improved Kit (QIAamp DNA Mini Kit) shows a high PCR positive rate. Besides, blood smear staining and use of oil for microscopic examination do not affect DNA extraction.

[Studies on the immuno-protection of ROP2 nuclei acid vaccine in Toxoplasma gondii infection].

OBJECTIVE: To study the protective effect of ROP2 nuclei acid vaccine in mice. METHODS: Forty-two BALB/c mice were divided into three groups. Each mouse in experiment group was injected with 50 microg recombinant plasmid pc-DNA3-ROP2 through musculus quadriceps fexoris. In control groups, each mouse was injected with 50 microg blank plasmid pc-DNA3 and with 50 microl PBS respectively. All mice were immunized for three times with an interval of three weeks. The volume was doubled for the final injection in the two plasmid groups. Blood, spleens and lymph nodes of 4 mice in each group were taken for the detection of CD4+, CD8+ T cells and cytokines 2 weeks after the final immunization. The rest mice in 3 groups were challenged with 500 tachyzoites of Toxoplasm gondii RH strain for further observation. RESULTS: The vaccine induced strong cellular and humoral immune response. The titer of antibody in serum was high after inoculation and recognized ROP2 protein antigen expressed in vitro. The lymphocyte phenotype was analyzed. CD4+ T cells proliferated sharply (69.5+/-3.4)%, and the ratio of CD4/CD8+ increased considerably by (4.69+/-1.32)% (P<0.01). The level of IL-2, IL4, IL-6, IL-12, IFN-gamma and TNF in serum and cultured supernatant of spleen cells and lymph cells was higher in the experiment group than that in control groups, especially in serum. 88.9% mice in the experiment group were protected 180 hours after the challenge of T. gondii. The death time of mice in experiment group was delayed and the survival time was prolonged in comparison to that in control groups with a significant difference (P< 0.01). CONCLUSION: The recombinant ROP2 nuclei acid vaccine shows fair immunogeni-city and obviously produces immuno-protection.

[Comparative study on EEG and neuroimaging of patients with cerebral cysticercosis before and after treatment].

OBJECTIVE: To study the changes of cerebral function and pathological morphology before and after the antiparasitic treatment with albendazole and praziquantel in patients with cerebral cysticercosis. METHODS: The data of EEG and neuroimaging of 412 patients with cerebral cysticercosis were retrospectively analyzed. RESULTS: Before the treatment, the mild abnormality, moderate abnormality, and severe abnormality were observed in 40.53%, 45.63% and 13.84% of the patients respectively, which mainly showed the diffuse or focal irregular slow waves, or epileptiform discharges found in the abnormal brain waves. CT/MRI manifestation could be divided into six types, including single sacculus type (23.59%), multiple sacculus type (44.42%), encephalitis type (13.59%), coexistence of macrocyst and sacculus type (4.85%), calcification type (2.18%), and mixed type (11.41%). After 3 courses of the treatment, the normal and improved EEGs were observed in 79.85% and 20.15%, respectively. CT/MRI showed the foci being all absorbed (77.18%), being most absorbed (20.63%), and being no changes (20.18%) which were calcified focus. When cerebral cysticercosis were in acute stage (the single and multiple sacculus type, encephalitis type, and macrocyst and sacculus coexistence type), the therapeutic effect was good; while in the mixed type, the therapeutic effect was relatively poor. If cysticercosis were in the calcification stage, the patients only needed the heteropathy. CONCLUSIONS: In the patients with cerebral cysticercosis, EEGs show the mild to severe abnormalities, and CT/MRI mainly shows the multiple sacculus type. After the treatment, the abnormal EEGs are gradually recovered and the low density foci can be all absorbed, but some calcified focus still exist in some patients.

[Clinical analysis of 91 cases of imported falciparum malaria from Africa].

OBJECTIVE: To explore the clinical characteristics, early diagnosis, and treatment of patients with imported falciparum malaria from Africa. METHODS: The clinical data of 91 imported falciparum malaria cases were analyzed by retrospective study. RESULTS: All the 91 cases had the history of mosquito bites. The clinical manifestation of these cases varied, including fever, headache, chill, diarrhea, anemia, thrombocytopenia, proteinuria, damage of liver function, abdominal ultrasonographic presentations (enlarged liver and spleen). All the patients were successfully treated with the combination therapy of artemether and primaquine. CONCLUSION: The key procedures for treating imported falciparum malaria are earlier diagnosis and effective therapy. The combination therapy with artemether and primaquine shows a high efficacy and low side effect and low relapsed rate.