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Objective: To explore the feasibility and mechanism of recombinant adenovirus Ad-pl4ARF in cancer gene therapy., Methods: The proliferation of different liver cancer cells was assessed by morphology and trypan blue assay. Cell apoptosis was confirmed by detecting phosphatidylserine (PS) externalization with Annexin V/PI double staining. The expression of related proteins was analyzed by Western bloting. Nude mouse model bearing subcutaneous transplanted BEL7402 tumor was established to study the therapeutic ability of Ad-pl4ARF., Results: Ad-pl4ARF suppressed cell growth and proliferation, and promoted cell apoptosis of cancer cell lines with different genetic background. Ad-pl4ARF inhibited growth of liver cancer cells ( HepG2, BEL7402) in a dose-dependent manner. Ad-pl4ARF lead to overexpression of Bax and p21, the downstream regulating genes of p53. In the experimental therapy on nude mice bearing subcutaneous transplanted BEL7402 tumor, Ad-pl4ARF suppressed tumor growth significantly., Conclusion: pl4ARF is a short gene and with powerful function, which are consistent with the requirements for tumor suppressor genes used in gene therapy. It may play an important role in gene therapy against malignancies in the future.

Objective: Based on two sets of data from occupational epidemiology, Benchmark dose (BMD) was applied to estimate biological exposure limit (BEL)., Methods: Cadmium exposed workers were selected from a cadmium smelting and a zinc products factory and control group was selected from doctors or nurses and staff from shops living in the same area; Urinary cadmium (UCd) was used as exposure biomarker and urinary beta(2) microglobulin (UBM), NAG (UNAG) and albumin (UALB) were as effect biomarkers. All urine parameters were adjusted by urinary creatinine. Software of BMDS (Version 1.3.2, EPA.U.S) was used to calculate BMD., Results: Calculated abnormal prevalence was based on the upper limit of 95% of effect biomarkers in control group; There are significant dose response relationship between the prevalence of effect biomarkers (UBM, UNAG and UALB) and exposure biomarker (UCd); BEL was 5 microg/g creatinine for UBM as effect biomarker, It consists with the recommendation of WHO; BEL was 3 microg/g creatinine for UNAG as effect biomarker; BEL can be estimated by using the method of BMD; the more sensitive biomarker would used, the more occupational people would protected., Conclusion: The application of BMD in estimating biological exposure limit (BEL) is proper. UNAG is suggested as most sensitive biomarker to be used to estimate BEL for cadmium exposure.

Objective: To estimate the benchmark dose for osteoporosis caused by cadmium exposure in a Chinese general population with an epidemiological study., Methods: The inhabitants living in both cadmium polluted and non-polluted areas served as the exposure group and the control group. Urinary cadmium (UCd) and Blood cadmium (BCd) were used as exposure biomarkers while the Z score was used as effect biomarker for the osteoporosis., Results: The UCd and BCd in the habitants of the polluted areas were significantly higher than those in the habitants of the control area on average (P < 0.05) and the UCd and BCd in the habitants of the highly polluted areas were significantly higher than those in the habitants of the moderately polluted area on average (P < 0.05). The bone mineral density was significantly decreased in the groups of the highest UCd and BCd level compared with the 5 microg/g Cr group with the significant difference (P < 0.05). The morbidity of the osteoporosis would increase significantly with the increase of the cadmium exposure (P < 0.05) with the linear correlation (P < 0.05). BMDs were calculated using BMDS Version l.3.2 software and BMDLs were also determined. The BMDL of UCd for cadmium-induced osteoporosis was higher than those representing cadmium-induced renal dysfunction., Conclusion: High level of cadmium exposure can induce osteoporosis, which occurs later than renal damage related to cadmium exposure. The BMD is a practical method.

Aim: To characterize p62 expression and define the relationship between p62 expression and cell proliferation in primary carcinomas of the digestive system., Methods: p62 expression was characterized in surgically resected tumor specimens from 60 patients with primary carcinomas of the digestive tract (including 22 esophageal carcinomas, 17 gastric carcinomas, and 21 colorectal carcinomas) and 40 patients with hepatocellular carcinoma (HCC) by immunohistochemistry (IHC). The cell proliferation was determined by IHC of Ki-67 in 40 patients with HCC., Results: Twenty-two cases of esophageal carcinoma were histopathologically diagnosed as squamous cell carcinoma. We combined the gastric and colorectal carcinomas based on the equivalent histology. The 38 tumors in the combined groups, consisted of 17 well-differentiated, eight moderately differentiated, nine poorly differentiated carcinomas, and four mucinous adenocarcinomas. According to the criteria of Edmondson and Steiner, 40 patients with HCC were graded (2 grade I, 17 grade II and 21 grade III). p62 expression in primary carcinomas of the gastrointestinal tract (60/60,100%) was higher than that (27/40, 67.5%) of HCC (P<0.01, chi(2) = 19.63). High expression levels of p62 were positively correlated with histological grades in gastric and colorectal carcinomas (P<0.0001) and inversely associated with those in HCC (P = 0.0322). No significant correlations were observed for esophageal carcinomas (P = 0.8246). p62 expression was also detected in the cytoplasm of morphologically normal columnar epithelial cells adjacent to the cancer foci of gastric and colorectal carcinomas. In 40 HCC specimens, the mean Ki-67 labeling index (LI) was (19.6+/-16.0)%. It was (28.3+/-18.73)% in 12 cases with high p62 expression (+++), (7.53+/-14.83)% in 13 cases without p62 expression(-). Patients with a high p62 expression showed a significantly higher level of Ki-67 staining than those without p62 expression (P<0.05, t = 2.069)., Conclusion: p62 expression is common in carcinomas of the digestive system and higher in carcinomas of the gastrointestinal tract than in primary HCC. p62 is a cellular differentiation-related protein. Cancer cells with a high p62 expression exhibited highgrowth fractions in HCC.

Objective: To investigate the histological characteristics of hepatocellular carcinoma with p62 expression, and the correlation of p62 protein with biological characteristics of the cancer cells such as proliferation and metastasis., Methods: The immunohistochemical expression of p62 and Ki-67 were studied in 40 primary hepatocellular carcinomas., Results: 67.5% (27/40) exhibited positive staining of p62 protein in the cytoplasm of malignant cells, of which the strong positivity was mainly found in pathologic grade III cases. The cases with strong positive staining of p62 exhibited extensive fibrosis in the stroma and massive necrosis of the tumor. These cases also exhibited high proliferation activity, the mean Ki-67 labeling index was 28.3% +/- 15.1%, which was significantly higher than that in p62 negative ones (t = 3.087, P = 0.005). Three of five cases with lung or celiac lymph node metastasis exhibited strong positive staining of p62., Conclusion: There is some relationship between the expression of p62 protein, proliferation activity and metastasis of cancer cells as well as with the microenvironment which have abundant fibrous tissue in the stroma.

Objective: To study the role of Anopheles anthropophagus in malaria transmission and transmission threshold so as to provide basis for vector surveillance and malaria control strategy., Methods: Parasitological and entomological methods were used in the investigation at 5 villages of Xinyang City, Henan Province., Results: From July to August, 1999, 74 febrile cases (10.9% of the total population) were examined. Among them 50 were infected, the incidence in the population of surveyed spots was 7.4%. Active detection was made in another randomly selected two villages and found that the parasite rate in the inhabitants was 2.0%, and the positive rate of IFA was 8.4%. Only vivax malaria was detected. An. anthropophagus and An. sinensis were collected, with An. anthropophagus as the predominant one in human dwellings. The estimated man-biting rate and the human blood index were 4.9388 and 0.7858 respectively. The vectorial capacity of An. anthropophagus was 5.5296. The critical man-biting rate of An. anthropophagus was 0.2407 as calculated by the formula (ma = -rlnP/abPh) according to Macdonald's model. The local man-biting rate was 20 times higher than that of the critical man-biting rate., Conclusion: The results demonstrated that An. anthropophagus is the principal vector in malaria transmission in the area. The findings imply that the critical man-biting rate is of practicable importance in vector surveillance.

This paper presents the results of a study on simplified surveillance methods conducted in 23 pilot counties in 11 provinces and municipalities in China where reside 15 million people and malaria control has been in the late consolidation phase. Two simplified surveillance Schemes (A and B) taking treatment of clinical cases as the main measure were implemented in 1992-1994. The rate of annual blood examination for case detection was 1.0% in pilot Scheme A, while in areas of scheme B it was 0.3%. The implementation of both Scheme A and Scheme B, simplified or without treatment of infection foci and management of mobile populations, acquired satisfactory effects against malaria. Consequently, malaria incidence was declining steadily, only a few indigenous and introduced cases were detected. The parasite rate in residents and the IFA positive rate in children were very low. The results of pilot studies and cost-effectiveness analysis indicated that Scheme B is effective, rational and economic, and can be implemented to replace the routine surveillance measures in areas where malaria has been at the late consolidation phase in China.

Malaria is one of the major parasitic diseases in China. During the past 40 years, large scale malaria control activities were conducted in the country relying on primary health care nets and community participation. The control of malaria was implemented according to the principles of adopting integrated measures and repeated practices which are characterized by time- and locality-oriented approaches. As a result, remarkable success has been achieved. By the end of 1990, there were 117,000 malaria cases in China, with a morbidity of 0.0106%, which dropped by 95% in comparison with that in the 1950s. Most of the original hyper-endemic areas became meso- or hypo-endemic and for most of the previously meso- or hypo-endemic areas, the disease became sporadic. Malaria distribution and epidemic patterns also demonstrated great changes. The major experience comprises the integration of the malaria control program into the overall national health program, the mobilization of various sectors, including the community, the investigators and technical personnel in research institutions and control services to participate and cooperate in solving problems and difficulties encountered.

Serratia marcescens produces a characteristic red pigment, prodigiosin, which is formed by the enzymatic coupling of 4-methoxy-2,2'-bipyrrole-5-bipyrrole-5-carboxaldehyde (MBC) and 2-methyl-3-amylpyrrole (MAP). Many clinical isolates which are resistant to multiple antibiotics are nonpigmented. However, the relationship of pigmentation (or nonpigmentation) to drug resistance of the strains has not yet been established. In this study we demonstrated the pigment synthesizing capability in the transconjugants obtained from nonpigmented mutants WF and 9-3-3 of S. marcescens under the condition of cell-to-cell contact. Mutant WF produces MAP while mutant 9-3-3 synthesized only MBC. After genetic transfer, the color of the recombinant colonies was red indicating the successful transfer of the pigment synthesizing capability. The antibiogram of the transconjugants indicated that they inherited the resistance characteristics to polymyxin B and chloramphenicol from their parent strains. further supportive evidence was obtained by spectroscopic and high performance liquid chromatographic analysis of the resulting pigments extracted from the pigmented transconjugants. The pigments produced by the transconjugants were similar, if not identical, to those produced by the wild type strain 08 and those synthesizes syntrophically. The possibility of simultaneous transfer of pigment synthesizing capability and drug resistance remains to be explored .