[Inhibition of Toxoplasma gondii excretory - secretory antigens on growth of murine Lewis lung carcinoma].

OBJECTIVE: To investigate the effect of Toxoplasma gondii excretory-secretory antigens (ESA) on CD4+ CD25+ Foxp3+ T (Treg) cells in mice carrying Lewis lung carcinoma, and examine the inhibitory effect of T. gondii ESA on tumor growth. METHODS: C57BL/6 mice were randomly assigned into the PBS group (n = 14) and the Lewis group (n = 34). Mice in the Lewis group were subcutaneously injected with 2 × 105 Lewis lung carcinoma cells in the right axilla, while animals in the PBS group were injected with the same volume of sterile PBS. On day 7 post-injection (D7), mice in the PBS group were further divided into the PBS2 group and the PBS2 + ESA group, of 7 mice in each group, and mice in the Lewis group were further divided into the Lewis2 group and the Lewis2 + ESA group, of 17 mice in each group. Then, mice in the PBS2 + ESA group and the Lewis2 + ESA group were intraperitoneally injected with 100 µL of ESA. The mouse spleen coefficient was calculated in each group 7 days post-injection with ESA, and the changes of Treg cell counts and the long-term tumor growth were measured in tumor-bearing mice. RESULTS: The spleen coefficient was significantly greater in the PBS2 + ESA group and the Lewis2 + ESA group than in the PBS2 (0.66% ± 0.09% vs. 0.30% ± 0.02%, P < 0.05) and Lewis2 groups (0.69% ± 0.07% vs. 0.33% ± 0.03%, P < 0.05) 7 days post-treatment with ESA, respectively, and the percentage of splenic Treg cells in splenocytes was significantly lower in the PBS2 + ESA group and the Lewis2 + ESA group than in the PBS2 (1.28% ± 0.14% vs. 2.06% ± 0.07%, P < 0.05) and Lewis2 groups (1.58% ± 0.14% vs. 2.44% ± 0.23%, P < 0.05), respectively. T. gondii ESA treatment caused a delay in tumor growth, and the tumor size was significantly smaller in the Lewis2 + ESA group than in the Lewis2 group (P < 0.05). CONCLUSIONS: T. gondii ESA may reduce the proportion of splenic Treg cells in splenocytes and inhibit tumor growth in mice carrying Lewis lung carcinoma.

[Anti-tumor effect of Plasmodium yoelii infection on melanoma in mice].

OBJECTIVE: To explore the anti-tumor effect of 17XL strains of Plasmodium yoelii (P.y) infection on melanoma in mice. METHODS: B16F10 tumor cells were axillarilly injected into the right flank of 20 C57BL/6 mice to establish tumor-bearing mouse models. The next day, the mice were randomly divided into a P.y infection group and control group, 10 mice each group. Each mouse of the P.y infection group was intraperitoneally injected with 1×106 red blood cells including 20% P.y infection red blood cells, and each one of the control group were intraperitoneally injected with 1×106 normal red blood cells of C57BL/6 mice. The time of tumor formation of the mice in the two groups was observed and the tumor volumes were measured. RESULTS: The time of tumor formation in the P.y infection groupï¼» (11.30 ± 0.21) dï¼½was significantly later than that in the control group ï¼» (10.40 ± 0.22) dï¼½ (P < 0.05). From the tumors could be accurately measured to the study end point, both the tumors of mice in the two groups were growing, and the tumor volumes of mice in the P.y infection group were significantly less than those in the control group at each time point (all P < 0.05). The growth rate of tumors in the P.y infection group ï¼» (71.10 ± 6.29) mm3/dï¼½ was significantly slower than that in the control group ï¼» (302.80 ± 49.94) mm3/dï¼½ (P < 0.05), and the growth rates of tumors everyday in the P.y infection group were significantly slower than those in the control group (all P < 0.05). CONCLUSIONS: The P.y infection can delay the occurrence of tumor and inhibit the growth of melanoma.

[Experience and analysis of excellent works of human parasitology in national medical colleges and universities].

Teaching competition is an effective way for college and university teachers to improve their teaching skills. Based on the teaching practice and experience in medical parasitology, this paper discusses several key issues in teaching competition including topics, teaching designs and teaching methods. It provides references for the teachers in department of parasitology of universities and colleges to improve the quality of classroom teaching.

Thermo-responsive properties driven by hydrogen bonding in aqueous cationic gemini surfactant systems.

A series of unexpected thermo-responsive phenomena were discovered in an aqueous solution of the cationic gemini surfactant, 2-hydroxypropyl-1,3-bis(alkyldimethylammonium chloride) (n-3(OH)-n(2Cl), n = 14, 16), in the presence of an inorganic salt. The viscosity change trend for the 14-3(OH)-14(2Cl) system was investigated in the 20-40 °C temperature range. As the temperature increased, the viscosity of the solution first decreased to a minimum point corresponding to 27 °C, and then increased until a maximum was reached, after which the viscosity decreased again. In the 16-3(OH)-16(2Cl) system, the gelling temperature (T(gel)) and viscosity changes upon heating were similar to those in the 14-3(OH)-14(2Cl) system above 27 °C. The reversible conversion of elastic hydrogel to wormlike micelles in the aqueous solution of the 16-3(OH)-16(2Cl) system in the presence of an inorganic salt was observed at relatively low temperatures. Various techniques were used to study and verify the phase-transition processes in these systems, including rheological measurements, cryogenic transmission electron microscopy (cryo-TEM), electric conductivity, and differential scanning calorimetry. The abovementioned phenomena were explained by the formation and destruction of intermolecular hydrogen bonds, and the transition mechanisms of the aggregates were analyzed accordingly.