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In order to stimulate the students interest in the learning of parasitolohy, enable the students to master the professional knowledge of parasitology and basic skiils of experimental operation, improve the ability of integrating theory with practice and analyzing and solving problems, cultivate medical talents with high quality, meet the needs of development of medical education, experimental teaching method of parasitolog has to be reformed in the process of experiment teaching. The authors discuss the influence of the reform of parasitologocal experimental teaching method on teaching effect. The reform achieves the goal through methods of strengthening the teacher management, perfecting the experimental design, associating with real life, combining the traditional teaching method with modern technology, playing a role of teaching specimens, making effective use of resources in the laboratory and so on. It is proved that the teaching quality of parasitological experiment has been improved by means of the reform in teaching method. [ABSTRACT FROM AUTHOR]

Objective: To observe the effect of pungent dispersion bitter purgation method (PDBPM) on the esophageal mucosal intercellular space of reflux esophagitis (RE) model rats., Methods: Totally 100 Wistar rats were randomly divided into the control group, the model group, the Western medicine group (WM), the Chinese medicine group (CM), 25 rats in each group. Rats in the control group only received switch operation. Rats in the rest three groups received modified partial cardia muscle incision combined pylorus ligation of external parts to prepare the RE rat model. Starting from the 3rd day after operation, WM mixture (Motilium 3. 2 mg/kg + Omeprazole Capsule 4.3 mg/kg + Hydrotalcite Tablet 161.4 mg/kg) was administered by gastrogavage to rats in the WM group. Rats in the CM group was administered by gastrogavage with Modified Banxia Xiexin Decoction (5.7 g/kg), 2.5 mL each time, twice daily for 14 consecutive days. Equal volume of normal saline was administered by gastrogavage to rats in the control group and the model group. On day 7 and 14, the lower esophagus pH value, general specimen of mucosa and histopathologic changes were observed. Intercellular spaces of esophageal epithelium were measured for a control study., Results: Compared with the same group at day 7, the lower esophagus pH value increased at day 14 (P < 0.01); the naked eye integral of esophageal mucosa and intercellular spaces of esophageal epithelium also decreased at day 14 in the CM group and the WM group (P < 0.05). Compared with the control group at the same time point, the lower esophagus pH value decreased in the model group (P < 0.01). The naked eye integral of esophageal mucosa, and intercellular spaces of esophageal epithelium increased in the model group with increased intercellular spaces (P < 0.01). Compared with the model group at the same time point, the lower esophagus pH value increased and the naked eye integral of esophageal mucosa decreased in the CM group and the WM group at day 7 and 14 (P < 0.01). Intercellular spaces of esophageal epithelium of RE model rats at day 14 was lower in the CM group and the WM group than in the model group (P < 0.01). Compared with the WM group, the lower esophagus pH value decreased at day 7 in the CM group (P < 0.05); the naked eye integral of esophageal mucosa and intercellular spaces of esophageal epithelium decreased at day 14 in the CM group (P < 0.05)., Conclusions: PDBPM had favorable treatment effect on RE model rats. The therapeutic effect was more obvious along with the therapeutic course went by. Its mechanism might be achieved through good repair effect on damaged mucosa, increasing the pressure of esophageal sphincter, and inhibiting gastric acid.

Objective: To explore the optimal cut-off values of waist-to-height ratio (WHtR) for detecting the severe central obesity and low body weight in adult Chinese population., Methods: A total of 30 630 participants aged 35-59 years from different areas in mainland China were surveyed for cardiovascular diseases risk factors in two independent cross-sectional studies that carried out in 1992-1994 and 1998, respectively. Indices, such as sensitivity, specificity for hypertension, abnormal glucose, high serum total cholesterol, low serum high density lipoprotein cholesterol and clustering of risk factors (number ≥ 2) were calculated to evaluate the efficacy individual cut-off point of WHtR. The cut-off point value for obvious central obesity was fixed on the point whose specificity of the point was gathered more than 90%. And the cut-off point value to indicate low weight was determined by the percentile distribution of WHtR, at which the 5th percentile of point, both in male and female population. Based on the principle of convenient and practical for use, the optimal cut-off point values of WHtR for low weight and obvious central obesity were determined., Results: The cut-off values of WHtR to detect severe central obesity were 0.54 and 0.57 for men and women, respectively. Additionally, the cut-off points of WHtR for each of the 4 cardiovascular risk factors to evaluate the severity separately ranged from 0.54 to 0.55 in male, and ranged from 0.57 to 0.58 in female. The 5th percentile of WHtR, which was the point value of WHtR to indicate low body weight, was 0.40 in both male and female population., Conclusion: Our data suggest that the optimal cut-off value of WHtR for defining severe central obesity and low body weight should be 0.57 and 0.40, respectively.

Objective: To understand the pathological changes of tissues and organs in Microtus fortis infected with Schistosoma japonicum for further insight into the biological dynamic variation and explore immune mechanisms of M. fortis against S. japonicum infection., Methods: The healthy M. fortis and mouse were infected with cercariae of S. japonicum through abdominal skin. On the day 12, 20 and 40, the M. fortis and mouse were sacrificed by cervical dislocation and dissected. The liver and kidney slices of M. fortis and mouse of the different groups were prepared and stained with hematoxylin eosin stain (HE) by conventional techniques, respectively., Results: We did not find obvious lesions on the internal organs of mouse 12 d and 20 d after the infection and the lesions of M. fortis 40 d after the infection. However, white nodules appeared on the liver, kidney and spleen of the M. fortis 12 d and 20 d after the infection, and there were a lot of S. japonicum worms on pathological sections of inflamed liver and kidney tissues, and the boundary between worms and normal organization was clear. There were no parasites on pathological section of liver and kidney of mouse 12 d and 20 d after the infection., Conclusion: Among M. fortis, there are severe immune responses and the immune responses have an individual difference 12 days after S. japonicum infection.

Objective: To study the efficacy of waist circumference (WC) and waist-to-height ratio (WHtR) in predicting central obesity among the Chinese adult population., Methods: A total of 30 630 participants aged 35 - 59 from different areas in mainland China were surveyed for the risk factors of cardiovascular diseases (CVD) in two independent cross-sectional studies that were carried out in 1992 - 1994 and 1998, respectively. In subgroups with different heights, consistency analysis for central obesity diagnosed by WHtR (≥ 0.50) and WC (≥ 85 cm for men, ≥ 80 cm for women) were conducted. Sensitivity and specificity for predicting the clustering of risk factors (number ≥ 2) would include hypertension, abnormal glucose, high serum total cholesterol and low serum high density lipoprotein cholesterol and they were also calculated to evaluate the efficacy of prediction, with the two indices in the different height subgroups as well., Results: The consistency of diagnosis on central obesity by WC and WHtR was good in the whole population (the Kappa value was 0.805 in men and 0.816 in women), but poor (all Kappa values ≤ 0.6) for those with tall (men's height ≥ 180 cm and women's height ≥ 170 cm) or with short statures (men's height < 160 cm, and women's height < 150 cm). Sensitivity in the shorty subgroups and specificity in the tall subgroups appeared poor in both genders, by using WC criteria to predict the clustering of risk factors. However, the sensitivity (ranged from 56.1% to 64.1% for men and 64.7% to 73.2% for women) and specificity (from 70.0% to 74.5% for men, 59.2% to 75.9% for women) seemed good and stable in all the subgroups as well as in both genders by using the WHtR criteria., Conclusion: WC and WHtR could both be applied in predicting the clustering of risk factors of CVD and in evaluating the central obesity in the whole population. With satisfactory efficacy, WHtR seemed to be better than WC in the prediction of central obesity, both in men or women with tall or short statures.

Objective: To establish the technique of isolation and culture of lung fibroblasts from Microtus fortis in vitro, and observe the killing effect of lung fibroblasts on schistosomula., Method: The shape and growth characteristics of lung fibroblasts, isolated from new-born Microtus fortis at the ages of 1, 3 and 5 days and cultured in DMEM and RPMI 1640 culture media respectively, were observed by inverted microscope after tissue adhering and trypsin digesting. The mortality rate of schistosomula was counted after co-culturing with the supernatant of 2nd and 3rd generation of Microtus fortis lung fibroblasts (MfLF) for 96 h respectively, and the schistosomulum-killing effect was observed by inverted microscope., Results: The fibroblasts grew well by using tissue adherence method. MfLF cultured in both DMEM and RPMI 1640 media showed no difference. One to 3-day-old rats revealed better cell viability and purity. HE staining showed that the MfLF had an oval-shape nucleus and was passaged 4-5 times only in vitro. The culture supernatant of the second and third generations MfLF caused 9.5% and 10.5% death rate of schistosomula in 96 h respectively, with no significant difference to the negative control (8.8%)., Conclusion: The tissue adherence method developed is suitable for culturing the lung fibroblasts of M. fortis but the culture supernatant shows no effect in killing schistosomula.

The aggregation and spectral properties of three sandwich thulium bisphthalocyanine compounds in chloroform solution and LB films were investigated by using UV-Vis absorption spectra. The experimental results indicated that the three sandwich thulium bisphthalocyanine molecules formed H-aggregates in the chloroform solution, but the absorption spectra of the three sandwich thulium bisphthalocyanine compounds display strong absorption peaks of monomer when the concentration of the sandwich thulium bisphthalocyanine solutions was 10(-7) mol x L(-1). The addition of substitutent --OC8H17 not only decreased the aggregation behaviors of the sandwich thulium bisphthalocyanine, but also leaded to red-shift of the absorption peaks, and it had a biggish influence on the intensity of absorption spectra. The absorption Soret bands were splitting when the substitutent --OC8H17 was added. The substitutent --OC8H17 had a strong effect on the existence state of bisphthalocyaines in LB films, while TmPc2 and TmPcPc* molecules formed H-aggregates in LB films, however TmPc2* molecule formed T-aggregates. In the LB films, the distance between sandwich thulium bisphthalocyanine molecule was shortened, and the interaction of molecules was enhanced, therefore the absorption peaks were red-shifted compared with those in the solution, and the arranging state of sandwich thulium bisphthalocyanine molecule has biggish influence on the peaks of absorption spectra.

The configuration state and spectral properties of sandwiched thulium bisphthalocyanine (TmPc2) molecule in Langmuir films and Langmuir-Blodgett (LB) films were investigated by using the surface pressure-area (pi-A) isotherm and UV-Vis absorption spectra. The experimental results indicated that the sandwiched thulium bisphthalocyanine molecules form well-ordered stable monolayer films on the water/air interface, and the sandwiched thulium bisphthalocyanine molecules take the face to face orientation for the macrocycles and edge-on configuration in pure films, with the collapse pressure being 56 mN x m(-1). But the sandwiched thulium bisphthalocyanine molecules take the face-on configuration in the sandwiched thulium bisphthalocyanine films mixed with arachidic acid (AA), and the collapse pressure is more than 60 mN x m(-1). The sandwiched thulium bisphthalocyanine molecule could form well stable Langmuir films on sub-phase surface. The mixed TmPc2/arachidic acid not only could form well stable Langmuir films, but also could be transferred to solid substrate and deposited LB multilayers. In the chloroform solution and LB films of sandwiched thulium bisphthalocyanine, the UV-Vis absorption spectra have two absorption bands, namely Soret-bands and Q-bands. The electron orbit of sandwiched metal bisphthalocyanines was calculated by using absorption spectra VEH (Valence effective Hamiltonian) theory, and the electron transition orbit corresponding to the absorption peaks was analyzed. The Soret absorption band has two absorption peaks that are correlated with the electron orbital transitions of 184-187* and 178-186, and four absorption peaks of the Q absorption band are correlated with the electron orbital transitioned of 186-189*, 190* and 185-187*, 188*. In the LB films, the absorption peaks were red-shifted compared with those in the solution because of the interaction of molecules. The interaction of intra-layer molecules was stronger than that of interlayer molecules.

Objective: To screen differentially expressed genes in placentas with hepatitis B virus (HBV) infection and to discuss the molecular mechanism of HBV intrauterine infection., Methods: Thirty placenta tissue specimens from HBsAg and HBV DNA positive pregnant women were used as the study group and 30 placenta tissue specimens from normal pregnant women with HBsAg and HBV DNA negativity were served as the control group. The suppression subtractive hybridization (SSH) technique was used. Total RNAs of placenta tissue of the study group were mixed as the tester, and total RNAs of placenta tissue of the control group were mixed as the driver. A subtractive cDNA library was constructed by PCR-selective cDNA subtraction systems. Amplifications of the library were carried out with E. coli strain DH5alpha by reverse spot hybridization. RT-PCR confirmed that phosphatidylinositol 3-kinase (PI3K) was up-regulated in placenta tissue with HBV infection., Results: Colony PCR showed that the clones contained 200 - 1000 bp inserts. Thirty five clones were confirmed by reverse spot hybridization and analyzed by sequencing and bioinformatics. Thirty three known genes and 2 genes with unknown function were obtained. RT-PCR preliminarily confirmed that PI3K gene was up-regulated in HBV infected placenta., Conclusions: The differentially expressed genes in placentas with hepatitis B virus (HBV) infection using SSH technique has been screened out successfully. These differentially expressed genes encoding proteins participating in cell vital metabolism and malformation, and signal conduction-antiapoptosis pathway. This finding brings some new clues for studying the mechanisms of HBV intrauterine infection.

Objective: To study the mechanism and significance of peripheral blood mononuclear cell (PBMC) of neonates infected with hepatitis B virus (HBV)., Methods: Eighty-four HBsAg-positive and HBeAg-negative mothers and their newborns were recruited in this study. Sixteen hepatitis B virus markers (HBVM)-negative mothers and their neonates were served as control. All these cases had no symptoms of hepatitis, serious pregnancy complications and preexisting disease. Age, gestational age and the method of delivery were matched in two groups (P > 0.05). Five ml blood samples were taken from the peripheral vein of the pregnant women before delivery and from neonates within 24 hours after birth, before inoculation of HBV vaccine (HBVac). Serum and PBMC were isolated from 2 ml and 3 ml samples respectively. The sera, PBMC and the last supernatant of PBMC washing were stored at -80 degrees C. HBVM of neonates were detected by using enzyme linked immunosorbent assay (ELISA). HBV DNA in serum, PBMC and the last supernatant of PBMC washing of mothers and neonates were detected by using a nested-polymerase chain reaction (n-PCR). Two pairs of oligonucleotide primers, the outer primer pair for first PCR and inner primer pair for second PCR, designed according to region S of HBV genome were synthesized at Shanghai Cell Biology Institute of Chinese Academy of Sciences. The neonates who were HBV DNA positive in PBMC but HBsAg and HBV DNA negative in serum were followed up for one year, HBsAb in serum and HBV DNA in PBMC were observed in the neonates., Results: (1) The positive rate of HBV DNA in 84 serum and PBMC of mothers were 53.57% and 40.48%, respectively (chi(2) = 2.891, P > 0.05). All the results were weakly positive. (2) Twenty-four (28.57%) newborns in the study group were infected, including 7 who were only HBV DNA positive in serum, 11 only HBV DNA positive in PBMC and 6 in both, all the results were weakly positive. HBsAg was negative in all the newborns. None of the neonates in control group was infected with HBV. There was significant difference between the two groups (chi(2) = 4.55, P < 0.05). (3) Of all the study cases, 11 (13.10%) neonates were HBV DNA weakly positive in PBMC but HBsAg and HBV DNA negative in serum. Of their mothers, 5 were only HBV DNA positive in serum, 2 only positive in PBMC and 4 positive in both serum and PBMC. Seven of the 11 neonates were followed up for one year and at the end of follow-up, 4 were HBsAb positive and HBV DNA negative in PBMC; 3 were HBsAb negative, and among the 3 cases HBV DNA in 2 was still positive in PBMC, HBsAg and HBV DNA in serum were negative in all the 7 neonates., Conclusion: (1) HBV DNA positivity either in serum or in PBMC in mothers can result in infection of PBMC with HBV in their neonates. (2) PBMC infection with HBV can exist for a long time in neonates while HBsAg and HBV DNA are negative in serum, and may result in vaccination failure in neonates.

Objective: To study the role of the HBV-infected mothers' PBMC in intrauterine transmission of HBV to their fetuses., Methods: Thirty pregnant women with serum HBV DNA negative and PBMC HBV DNA positive and their newborns were used as the study group. Ten pregnant women with serum HBV negative and their infants served as the control group. HBV DNA in serum and in PBMC was detected using nested polymerase chain reaction (n-PCR). The mothers' PBMC in newborns' peripheral blood was examined using heminested-PCR., Results: Four newborns were serum HBV DNA positive and 8 newborns were HBV DNA positive in PBMC in the study group. Among them, 2 newborns were HBV DNA positive in both serum and PBMC, 6 cases were positive in PBMC only, and 2 cases were positive in serum only. Five mothers had the GSTM1 gene; and it was not detected in 3 newborns. Among the 8 newborns with HBV DNA positive in PBMC, 3 did not have the GSTM1 gene, at the same time their mothers possessed the GSTM1 gene. Mothers' PBMC were detected in all of these three newborns' peripheral blood. HBV DNA in serum and in PBMC of the control group infants were all negative., Conclusion: HBV-infected PBMC of the mother may serve as a vector in HBV intrauterine infection.

Objective: To investigate the expression of human annexin-V (HA-V) in relation to HBV infection in different fetal tissues., Methods: Immunohistochemistry was employed to detect the expression and distribution of HA-V in the liver, kidney, ovary, heart, fallopian tube, spleen, and thymus gland of human fetus., Results: HA-V expression was detected in different tissues including the ovary, liver, intrahepatic bile duct, heart, kidney, lymphocytic cells in the thymus gland, epithelial cells of the fallopian, and cortical and medullary cells of the spleen. HA-V was distributed mainly in the cytoplasm of the cells. The liver tissues exhibited greater gray scale for HA-V expression than in the other tissues (P<0.05) and no significant difference was observed in the other tissues than the liver (P>0.05) in image analysis with Photoshop 7.0., Conclusion: HA-V is an inherent protein in fetal tissues with possible relation to HBV infection of different tissues as a HBV receptor. Greater amount of HA-V in the liver may account for the vulnerability of the liver to HBV infection.

Objective: To understand the HBV infection rate of peripheral blood mononuclear cells (PBMCs) from fetuses of HBsAg positive mothers, associated risk factors and to explore the clinical significance of detecting HBV infected PBMCs., Methods: Sixty eight pregnant women who were delivered at the First Hospital of Xi'an Jiaotong University, China from August 1995 to February 1997, and their newborns were studied. They were divided into two groups according to their status of HBV serological markers. The study group included 50 cases who were serum HBsAg positive and 18 cases without any HBV serum markers served as control group. All these cases had no symptoms of hepatitis, high risk premature labor, premature delivery and hypertensive disorder complicating pregnancy. Age and gestational age were matched in two groups. Blood samples (5 mL) were taken from the peripheral vein of pregnant women before delivery and from newborns within 24 h after birth, before inoculation of HBV vaccine (HBVac) and injection of hepatitis B immunoglobulin (HBIG). PBMCs were isolated. The sera and PBMCs were stored at -80 degrees C. HBV-DNA in serum and PBMCs were detected with nested polymerase chain reaction (n-PCR). Two pairs of oligonucleotide primers, the outer primer pair for first PCR and inner primer pair for second PCR, designed according to region S of HBV genome were synthesized by Shanghai Cell Biology Institute of Chinese Academy of Science., Results: The detection rate of HBV-DNA in serum and PBMCs from HBsAg positive pregnant women was 60.0% (30/50) and 40.0% (20/50), respectively. The detection rate of HBV-DNA in serum and PBMCs from newborns of HBsAg positive pregnant women was 46.0% (23/50) and 30.0% (15/50), respectively. Ten newborns were HBV-DNA positive in serum only, 2 were positive in PBMCs only and 13 were positive in both serum and PBMCs. In the control group, HBV-DNA was not detected in PBMC nor in serum. The positive rate of HBV-DNA in PBMCs of newborns was significantly higher in the group of mothers who were HBV-DNA or HBeAg positive in serum (P < 0.05, P < 0.01); the positive rate was significantly higher in the group of mothers who were HBV-DNA positive in both serum and PBMC than that in the group of mothers who were serum HBV-DNA positive only (P < 0.01); and it was markedly higher in the group of mothers who were PBMC HBV-DNA positive than that in group of mothers who were HBV-DNA negative in PBMCs (P < 0.01). The positive rate of HBV-DNA in PBMCs of newborns was significantly higher in the group of newborns who were HBV-DNA positive in serum than that in the group of newborns who were HBV-DNA negative in serum (P < 0.05)., Conclusions: The positive rate of HBV-DNA in PBMCs from newborns of HBsAg positive pregnant women was 30.0% (15/30). It was related to HBV viremia level and HBV-DNA status in PBMCs of mothers and newborns. Detection of HBV-DNA in PBMCs may be an important supplementary method to determine intrauterine HBV infection, and can predict the response to HBV vaccine.

Objective: To explore the significance of intrauterine infection of hepatitis B virus in pregnant women with hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) negative by nested polymerase chain reaction (PCR)., Methods: Twenty-four pregnant women with HBsAg and HBeAg negative but other HBV markers positive together with their infants were included as study group. Sixteen pregnant women with HBV marker negative and their infants were in the control group. HBV DNA in sera and peripheral blood mononuclear cells (PBMCs) of two groups was detected by nested PCR respectively., Results: (1) In the study group, the positive rates of HBV DNA of pregnant women were 33% (8/24) in the sera and 42% (10/24) in PBMCs. Three women were detected HBV DNA in both serum and PBMCs. The rate of HBV infection was 63% (15/24); (2) also in the study group, the positive rates of HBV DNA of the infants were 13% (3/24) in the sera and 25% (6/24) in PBMCs. One newborn was detected HBV DNA in both serum and PBMCs, the rate of intrauterine infection of HBV was 33% (8/24); (3) HBV DNA was detected in sera and/or in PBMCs from four newborns of pregnant women with HBV DNA positive only in PBMCs, the positive ratio was 4/7., Conclusions: HBV intrauterine infection is possible in pregnant women with HBsAg and HBeAg negative. Detecting HBV-DNA in sera and PBMCs of pregnant women and their newborns by PCR is important clinical significance.

Objective: To explore the possible mechanism of placental dysfunction in patients with intrahepatic cholestasis of pregnancy (ICP)., Methods: Serum level of cholylglycine (CG) in 30 cases with ICP (ICP group) and 27 normal pregnant women (control group) was examined by radio-immunoassay before delivery. bax and bcl-2 level in placenta was detected by immunohistochemistry method., Results: (1) Serum CG level in ICP group was (51.8 +/- 5.9) micro mol/L, and in control group it was (9.4 +/- 5.6) micro mol/L. The difference between the two groups was significant (P < 0.05). (2) bax expression level in syncytiotrophoblast of ICP group was: 2(-), 9(+), 11 (++), 8(+++), and bcl-2 expression level was: 12(+), 12(++), 6(+++); bax expression level in control group was: 9 (-), 13(+), 4(++), 1(+++) and bcl-2 expression level was: 3(+), 4(++), 20(+++). bax expression level in syncytiotrophoblast of ICP group was higher than that of the control (P < 0.0005), and bcl-2 expression level was lower than in the control (P < 0.0005), both significantly. A significant positive correlation between CG level and bax expression level and a negative correlation between CG and bcl-2 were found in ICP group (P < 0.005, P < 0.005)., Conclusion: One of the possible mechanisms involved in placental dysfunction of ICP is overexpression of bax in syncytiotrophoblast caused by high concentrations of bile acid, leading to increased apoptosis.

Objective: To investigate the optimal condition for in vitro cultivation of Trichomonas vaginalis for obtaining a better harvest of T. vaginalis., Methods: An isolate of T. vaginalis from clinical specimens was cultivated in three different media with initial inoculation of 9.0 x 10(4)/ml under pH 5.6., Results: There was distinct difference after 96 h incubation in the cumulative harvest of T. vaginalis. The highest harvest was received in cysteine/liver/peptone/maltose medium, followed by the liver/peptone/maltose medium and soybean/liver/peptone/maltose medium., Conclusion: The cysteine/liver/peptone/maltose medium may be a suitable environment for in vitro multiplication of T. vaginalis.