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Biomedical subjects

G Zeng

Publications and source records attributed to G Zeng.

86 records · Page 5Linked to original sources
PubMed1994

[Study and improvement of Reed-Frost model].

The purpose of this paper is to modify the Reed-Frost theory of epidemics with the underlying assumptions of the model including the occurrence of inapparent infections, and their influence on the course of the epidemic. With this model two epidemics were computed: (1) the Aycock outbreak of measles in a New England boy-boarding school in 1934; (2) the outbreak of chickenpox in a Shanghai kindergarten in 1950. The calculated and observed results were well in agreement. A substantial improvement in fitness was shown as measured by chi-square tests. As presented, the model offers a reasonably good explanation on the occurrence of inapparent infections and its effect on the pattern of the disease.

Chickenpox↗
PubMed1990

[The use of Bayes' theorem in controlling the coming epidemic peak of epidemic meningitis in the 1980s].

To control the coming epidemic peak of epidemic cerebrospinal meningitis (ECM) in the 1980s in the regions with 100 million population in China, the mathematical models based upon Bayes' theorem (BT) were established and used respectively in provincial, regional and county's level. Reports of ECM from each ten-day's period or each month during the meningitis season were analysed to create forecast models. Records of ECM vaccinating rate in previous years were fully taken into account to modify the theoretical values. Calibration, split-sample, random-sample selection, as well as actual forecast tests, were used to check the efficiency of the models. The distribution of meningitis vaccine was planned according to the final predictive results. The incidence rates of ECM of above regions decreased obviously faster than other areas in China. Attributing the application of BT forecast research, it was estimated only in Henan province 79795 ECM cases; 4388 deaths and 21 million Yuan economic damage were avoided during the 4 years period, from 1985 to 1988.

Bayes Theorem↗
PubMed1988

An assessment of the use of Bayes' Theorem for forecasting in public health: the case of epidemic meningitis in China.

A mathematical model based upon Bayes' Theorem (BT) was used to forecast the occurrence of epidemic cerebrospinal meningitis (ECM) in ten communities in North China. Reports of ECM from each ten-day period during the meningitis season and records of special population movement during 1960-82 were analysed to establish forecast models. Calibration, split-sample, random-sample selection, as well as actual forecast tests, were used to check the efficiency of the models. For all the tests, the theoretical occurrence of ECM forecast by the BT method was compared with the observational data. Since the BT method offers efficiency and convenience, it is recommended for use in planning for the prevention and control of ECM in China.

Bayes Theorem↗
PubMedDate not supplied

Role of tumor-associated gangliosides in cancer progression.

Neuroectodermic tumors can mostly be characterized by the presence of tumor-associated glycosphingolipid antigens, such as gangliosides, defined by monoclonal antibodies. Recently, cumulative evidence indicates that gangliosides modify the biological effects of several trophic factors, in vitro and in vivo, as well as the mitogenic signaling cascade that these factors generate. The functional roles of gangliosides in tumor progression can be revisited: (i) ganglioside antigens on the cell surface, or shed from the cells, act as immunosuppressors, as typically observed for the suppression of cytotoxic T cells and dendritic cells, (ii) certain gangliosides, such as GD3 or GM2, promote tumor-associated angiogenesis, (iii) gangliosides strongly regulate cell adhesion/motility and thus initiate tumor metastasis, (iv) ganglioside antigens are directly connected with transducer molecules in microdomains to initiate adhesion coupled with signaling, and (v) ganglioside antigens and their catabolites are modulators of signal transduction through interaction with tyrosine kinases associated with growth factor receptors or other protein kinases. Given the potential importance of these sialylated gangliosides and their modulating biological behavior in vivo, further studies on the role of gangliosides are warranted.

Adjuvants, Immunologic↗
PubMedDate not supplied

Effectiveness of a worksite nutrition education activity in a factory in China.

To evaluate the effectiveness of a worksite nutrition education activity in China, a two-group pretest-posttest nutrition education lesson was designed and carried out in two divisions (N = 240 in each division) of a steel tube factory in Chengdu, Sichuan. Special features of the program were nutrition education materials developed from both (a) the results of a pretest survey of the employees, and (b) focus group discussions conducted with factory hospital and workteam staff; a colloquial style; a slogan; and an illustrated handout depicting the new Chinese Dietary Guidelines and a proposed Food Guide. Analysis of variance, chi-square, and t-tests showed both significant increases (p < 0.05) in nutrition knowledge and attitude scores and significant improvements in dietary practices in the group receiving the education. It is concluded that the method is a useful and practical model for designing and developing worksite nutrition education in China.

China↗
PubMedDate not supplied

MHC class II-restricted tumor antigens recognized by CD4+ T cells: new strategies for cancer vaccine design.

The adoptive transfer of tumor-infiltrating lymphocytes (TIL) can mediate tumor regression in patients with melanoma. This finding has led to the identification and characterization of tumor-associated antigens recognized by CD8+ TIL. Several clinical trials based on the genes recognized by these CD8+ T cells have been attempted, but with only limited success. Meanwhile, increasing evidence has demonstrated that CD4+ T cells play important roles in generating and maintaining antitumor immune responses in animal models. These data suggest that it may be necessary to engage both CD4+ and CD8+ T cells for more effective antitumor immunotherapy. In this report, we review emerging molecular approaches in cloning major histocompatibility complex (MHC) class II restricted tumor antigens recognized by CD4+ T cells as well as approaches to identify new MHC class II-restricted epitopes from known tumor antigens recognized by CD8+ cytotoxic T lymphocytes and/or antibodies. Progress made in this field has shed light on the roles of tumor antigen-specific CD4+ T cells in humans; it has also provided new insights into the understanding of tumor genesis and the interaction between tumor and the immune system. More importantly, the discovery of MHC class II-restricted tumor antigens has provided opportunities for developing a new generation of cancer vaccines aimed at eliciting both CD4+ and CD8+ T-cell responses against tumor.

Adoptive Transfer↗
PubMedDate not supplied

Early post-operative ankle pressure indices help predict late patency rates after femoro-distal vein bypass grafting.

A prospective graft surveillance programme included 115 femorodistal autogenous vein bypass grafts that were patent when studied by measurements of ankle/brachial pressure indices (ABIs) at 3-5 weeks after operation. The grafts were followed for up to 3 years to determine whether early ABIs helped to predict subsequent failures, defined as graft thrombosis or graft or anastomotic stenosis causing diameter reduction greater than 75% treated by surgery or balloon dilatation. Receiving operating characteristics curves showed that resting ABIs predicted failure better than post-exercise ABIs or the differences between the two, and that an early resting ABI less than 0.85 was the optimal value to predict failure. Primary patency rates at 2 years were 88% for resting ABI greater than or equal to 0.85 and 36% for resting ABI less than 0.85 (p less than 0.0005). Most stenoses occurred in the grafts and not at anastomoses. Arteriographic grading of crural artery outflow was not significantly different for successful or failed grafts or for grafts with resting ABI greater than or equal to 0.85 or less than 0.85. The observation that late graft failure was 3-4 times more likely if the early post-operative ABI was low suggests that most graft failures result from faults relating to the operation.

Aged↗