BACKGROUND: Studies have confirmed that there is secreted protein out of cell wall of Candida albicans. However, in recent researches, we found there may be a capsule-like-structure within it.OBJECTIVE: To observe the capsule-like structure of Candida albicans by means of modified quellung test.DESIGN: A controlled observation experiment.SETTING: Department of Medical Microbiology, Gannan Medical College.MATERIALS: Candida albicans from 2 clinical specimens (C1, C2) identified by preserve center of Epiphyte strains of Chinese Academy of Science (Nanjing, China) and standard strains (CCCMC1a and ATCC14053) donated by preserve center of Epiphyte strains of Peking University (Beijing, China) were taken to quellung test. Experimental rabbits (weighing 2-2.5 kg) for preparing normal serum and antiserum were donated by Experimental Animal Center of Sun Yat-sen University. Antiserum was prepared by the book with experimental strains (C1, C2, CCCMC1a, and ATCC)respectively for later quellung tests.METHODS: This experiment was carried out in the Department of Medical Microbiology, Gannan Medical College in December 2005. ① Traditional Quellung test: The culture of Candida albicans (C1, C2, CCCMC1a, and ATCC) was spread on a slide respectively. Corresponding rabbit antiserum was added onto the slide (experimental group 1) and normal serum was added onto the slide (control group1). 1% methylene blue was added into each group, and then the slides were placed in a wet box at 37 ℃ for 20 minutes; the slides were taken out and covered with a cover-slip. Under the oil immersion, the count of Candida albicans was taken and the microscopic surveying instrument was used to measure the capsule thickness of cell of Candida albicans directly. The average thickness of capsule of 40 cells was taken. ②Modified quellung test: The culture of Candida albicans (C1, C2, CCCMC1a, and ATCC) was spread on a slide respectively. Corresponding rabbit antiserum was added onto the slide (experimental group 2) and normal serum was added onto the slide (control group 2), 1% methylene blue was not added into each group, but the slides were directly placed in a wet box et 37 ℃ for 20 minutes. The slides were taken out and dried naturally, but not covered with a cover-slip during the drying process. Hiss capsule staining was applied for them.The average thickness of capsule of 40 cells was taken.MAIN OUTCOME MEASURES: The average thickness of capsule in each experimental group in traditional and modified quellung tests.RESULTS: ① Traditional quellung test of Candida albicans was positive. The thickness of culture of Candida albicans C1, C2, CCCMC1a, and ATCC of experimental group1 was larger than that of the control group1, respectively [(0.558+0.081 ) vs. (0.225+0.061) μm; (0.530+0.081) vs. (0.252+0.038) μm; (0.475+0.081) vs. (0.200+0.072) μm;(0.600+0.068) vs. (0.225+0.046) μm,P ＜ 0.01] .② The thickness of culture of Candida albicans C1, C2, CCCMC1a, and ATCC of experimental group 2 was larger than that of the control group 2, respectively[(0.541 ±0.038) vs. (0.215±0.022)μm; (0.510±0.060)vs. (0.247±0.018) μm; (0.487±0.041) vs. (0.213±0.033)μm; (0.595±0.027) vs. (0.220±0.016) μm, P ＜ 0.01]. ③ The thickness of capsule of the control group 2 was smaller than that of control group 1 (P ＜0.01); The thickness of capsule of the experimental group 2 was smaller than that of experimental group 1 (P ＜ 0.01).CONCLUSION: As a quantitative analysis test, modified quellung test is more stable and accurate than traditional quellung test.

We carried out a new unit-based method in the teaching process of epidemiology for improving undergraduate prevention-oriented medical students' comprehensive ability. The new method integrated heuristic teaching and case teaching, and focused reform on the system of teaching and assessment. The results showed new teaching method can significantly improve students' capacity of analysis and oral expression, and contributes to the comprehensive ability.

The purpose and meaning of epidemiology curriculum,the current problems existing in the teaching and teaching reforms for different specialties were discussed.

BACKGROUND: Previous studies have demonstrated that Candida albicans possesses capsule structure. Whether capsule structure is associated with the virulence of Candida albicans?OBJECTIVE: This study investigated the pathogenic difference between the standard strains of Candida albicans and the clinically isolated strains, verified whether capsule was the virulence factor of the Candida albicans, and analyzed the association between the animal pathogenicity of different strains and capsule thickness.DESIGN: A randomized controlled animal experiment.SETTING: Department of Pathogenic Biology, Gannan Medical College.MATERIALS: This study was performed at the Scientific Research Center, Gannan Medical College between May and June 2005. A total of 120 BALB/c mice and 72 healthy adult rabbits were included. Candida albicans strains (CCCMC1a and ATCC 14053) were used. The isolated and cultured 4 strains were numbered as C1-1, C1-2, C1-3,and C1-4.METHODS: All animals were randomly divided into 6 groups with 20 mice and 12 rabbits in each group, namely,CCCMC1a, ATCC 14053, C1-1, C1-2, C1-3, and C1-4 groups. Strains smeared in sabouraud ager medium for 36 hours were diluted into the bacterial solution with physiological saline. This solution was intravenously injected into rabbit ear edge, 1.5 mL per rabbit, and intraperitoneally injected into BALB/c mice, 0.5 mL per mouse. Six hours after administration, animal response was observed, and attack time, death time, and mortality were recorded.MAIN OUTCOME MEASURES: Rabbit nephridial tissue printing slices and mouse peritoneal fluid smears were made for Hiss capsule staining microscopy. The capsule thickness of 40 randomly selected yeast cells in each strain was measured using a microscope-micrometer, and the mean capsule thickness of each strain was compared.RESULTS: Compared with C1-1, C1-3, CCCMC1a, and ATCC 14053, C1-2 and C1-4 possessed stronger animal pathogenicity. The standard strains and clinically isolated strains could form capsule in the rabbit and mouse bodies. Capsule thickness differed due to different strains and animal genera (P < 0.05-0.01). The bacterial capsule thickness was greater in the rabbit renal infection focus than in the mouse abdominal cavity. The bacterial capsule thickness of rabbit renal infection focus and mouse abdominal cavity in the C1-1, C1-2, C1-3, and C1-4 groups was greater than that of the same genus in the CCCMC1a and ATCC 14053 groups. The bacterial capsule thickness of rabbit renal infection focus and mouse abdominal cavity was the greatest in the C1-2 and C1-4 groups.CONCLUSION: Candida atbicans C1-2 and C1-4 strains have strong animal pathogenicity. C1-2 and C1-4 strains possess greater bacterial thickness than other strains. It has been primarily confirmed that capsule is possibly a virulence factor of Candida albicans, and capsule thickness is closely associated with animal pathogenicity.

Objective: To understand hepatitis B virus(HBV) infection in high school students in Guangxi, and to provide scientific foundation for hepatitis B prevention and control strategies. Methods: A selfdesigned epidemiological questionnaire was used among 2 632 participants. Information regarding general demographic characteristics, lifestyle habits, HBV infection history, knowledge of viral hepatitis prevention and control, as well as hepatitis B vaccination. Univariate and multivariate logistics regression analysis was used to analyze associated factors for hepatitis B infection. Results: A total of 192 out of 2 632 participants were found HBsAg positive and 2 440 were HBsAg negative. Multivariate analysis showed that family liver disease history and hairdressing injury positively associated with hepatitis B virus infection risk (OR=3.62, 95% CI=2.28-5.73;OR=3.06, 95%CI=1.94-4.83), and hepatitis B vaccination was negatively associated with hepatitis B virus infection risk (OR=0.08, 95%CI=0.05-0.11). Conclusion Family history of liver disease, hairdressing injury experiences, as well as low rate of hepatitis B vaccination may associate with relatively high prevalence of hepatitis B virus infection among high school students in Guangxi.

Objective:To investigate the attitude of neonatologists toward the treatment of extremely preterm infants (EPIs) in China.Methods:A cross-sectional survey was conducted using a questionnaire designed and posted on Wenjuanxing, a web-based survey platform, from June to July 2021. The respondents were neonatal physicians in various provinces and cities in China. The questionnaire covered the basic information, treatment experience and attitude towards EPIs, and opinions on the current definition of the preterm infant in China. The results were described or analyzed using the Chi-square test.Results:A total of 1 066 valid replies were collected. The respondents included 322 males and 744 females, among whom 78.1% (832/1 066) were assistant director physicians or director physicians, 82.8% (882/1 066) were from tertiary hospitals, and 83.0% (885/1 066) had the experiences of treating EPIs. In terms of the attitude toward the treatment of EPIs, 63.0% (672/1 066) of the respondents suggested that the lower limit of gestational age for EPIs requiring active resuscitation should be defined at 25 gestational weeks or less. Moreover, 57.1% (609/1 066) considered that the current domestic definition of preterm infants as 28 gestational age or above was inappropriate, and 75.2% (458/609) considered that the lower limit defined as preterm infants should be 25 gestational weeks or less. Concerning the treatment experience in EPIs, 54.3% (579/1 066) of the respondents suggested that in their hospital, withdrawing treatment in EPIs was common or very common, and 83.3% (888/1 066) considered that the main reason for withdrawing treatment was family members' concerns about the prognosis. Those who hesitated about treating the EPIs accounted for 71.6% (763/1 066), and 83.9% (640/763) hesitated due to the poor prognosis and possible medical disputes. Moreover, 32.7% (349/1 066) of the respondents or their colleagues had been involved in medical disputes about whether to treat EPIs, and 74.8% (797/1 066) believed that the patients should be the decision-maker on whether to treat EPIs or not.Conclusion:Most neonatal physicians in this survey hold a positive attitude toward the treatment of EPIs and believe that the lower limit of gestational age for preterm infants should be lowered. However, a hesitating attitude to the care of EPIs is still common, and uncertainty about the prognosis of EPIs remains a concern.