[Zeng-Ding phenomenon: further demonstration and studies on its predictive value in epidemic of measles and scarlet fever]

OBJECTIVE

To demonstrate further the existence of Zeng-Ding phenomenon in disease epidemic and to explore the relationship between it and the time series in different kinds of diseases.

METHODS

Incidence data of notifiable communicable diseases during 1975 to 1996 were collected. Time series of measles and scarlet fever incidence during 1975 to 1995, 1980 to 1995, 1985 to 1995 and 1990 to 1995 were established. Correlation analysis was conducted between monthly cumulative percentage and predictive ratio of increase to decrease in incidence rate at the best cut-off point. Prediction was studied based on the constructed extrapolation model.

RESULTS

Correlation analysis showed that 98.3% (232/236) of the coefficients of correlation were negative (R < 0), indicating further the existence of Zeng-Ding phenomenon in disease epidemic. There was significant difference in coefficients of correlation between the four time series, which accounted for 63.8%, 54.2%, 44.1% and 35.0%, respectively; and for 73.3%, 56.7%, 36.7% and 36.7%, respectively, in measles, and for 53.6%, 51.8%, 51.7% and 33.3%, respectively, in scarlet fever. It showed that Zeng-Ding phenomenon correlated with the time series and the kinds of diseases. Prediction from extrapolation model showed that there was significant difference in predictive agreement between two time series of 1975 to 1995 (65.5%) and 1985 to 1995 (37.0%) with chi 2 of 4.54 and P < 0.05, indicating a trend that predictive agreement increased with prolonging of time series, and a trend that predictive agreement for scarlet fever increased with decreasing of coefficients of correlation.

CONCLUSION

Predictive value of the incidence data can be evaluated by their source and length of time series.

Alteration of ganglioside composition by stable transfection with antisense vectors against GD3-synthase gene expression

Gangliosides are ubiquitous components of mammalian cells. Their expression is frequently altered in many tumor types. We previously showed that alteration of the ganglioside composition often resulted in changes in cellular morphology and differentiation of cultured cells. In this study, we targeted sialyltransferase gene expression by the antisense knockdown experiment, and the results showed that inhibition of the expression of gangliosides GD3 and O-acetylated GD3 (OAc-GD3) in the neuroblastoma F-11 cells greatly reduced the tumor growth in nude mice. The sense and antisense vectors containing either a 5' end fragment or the entire sequence of the cDNA coding for GD3-synthase were prepared and used in separate experiments to transfect the F-11 cells which express high levels of gangliosides GD3 and OAc-GD3. Single clones were isolated and expanded. Both the activity of the GD3-synthase and the concentrations of GD3 and OAc-GD3 in the antisense-transfected cells were dramatically decreased as a result of transfection with the antisense expression vectors. Further characterization of the antisense-transfected cells showed reduced rates of cell growth and neurite formation and changes in cellular morphology. When the cells were inoculated in athymic nude mice, the tumor growth rate was remarkably suppressed although the tumor incidence was not affected by the altered ganglioside composition. These results indicate that the tumor-associated ganglioside(s) is(are) involved in regulation of tumor growth, probably through the stimulation of angiogenesis of the tumor.

[Effects of nutritional intervention on several chronic diseases in communities]

Eighty seven subjects with abnormal blood glucose, blood pressure and serum triglycerides and cholesterol were selected. They are living in the urban area of Chengdu. Nutritional intervention measures included making suggestions on recipe, nutrition education and consultation etc. The following parameters were observed: 1. fasting blood glucose and postprandial blood glucose at 2 h after meal; 2. serum triglycerides and cholesterol; 3. blood pressure and body weight, and 4. symptom score. Data were analyzed by paired t-test, correlation and stepwise regression analysis. The results showed that above parameters were significantly improved by the end of the study. It can be considered that reasonable diet is a simple and effective measure to control these chronic diseases in communities.

Molecular cloning and expression of mouse brain sialidase

Sialidase (EC 3.2.1.18) catalyzes the release of sialic acid from sialo-oligosaccharides, gangliosides, or sialo-glycoproteins. In this investigation, we cloned a novel cDNA for mouse brain sialidase and expressed the cDNA in COS-7 cells. This 1,699 bp cDNA codes for a 41.6 kDa protein consisting of 372 deduced amino acid residues. In COS-7 cells transiently transfected with the cDNA, a 250-fold increase was observed in specific activity toward 2'-(4-methylumbelliferyl)-alpha-D-N-acetylneuraminic acid. Similarity searches of the nonredundant GenBank peptide sequence database by the PSI-BLAST program identified rat, hamster, human, and bacterial sialidases homologous to this mouse brain sialidase. Amino acid sequence identities to rat and hamster sialidases (84% and 77%, respectively) suggest that this form of sialidase is conserved in rodents. Sequence identities to human and mouse lysosomal sialidases (30% and 28%, respectively) indicate that the mouse brain sialidase is distinct from the lysosomal enzyme. Mouse brain sialidase has two amino acid sequence motifs common to bacterial sialidases: the 'F/YRIP' motif and the 'Asp-box' motif. The 'F/YRIP' motif is present near the N terminus while two 'Asp-box' motifs are present downstream.

Down-regulation of the expression of O-acetyl-GD3 by the O-acetylesterase cDNA in hamster melanoma cells: effects on cellular proliferation, differentiation, and melanogenesis

The composition of the gangliosides of hamster melanoma cells is closely related to their cellular growth and degree of differentiation, with slow-growing, highly differentiated melanotic melanoma MI cells expressing GM3 and fast-growing, undifferentiated amelanotic Ab melanoma cells having a preponderance of GD3 and O-acetyl-GD3. To study the putative function of O-acetyl-GD3, we established stably transfected AbC-1 amelanotic hamster melanoma cells with O-acetylesterase gene from influenza C virus to hydrolyze the O-acetyl group from O-acetyl-GD3. The content of O-acetyl-GD3 in the transfected cells expressing O-acetylesterase gene was reduced by >90%. These O-acetyl-GD3-depleted cells differed from the parental ones in their cellular morphology, growth behavior, and melanogenesis activity. The absence of O-acetyl-GD3 in the transfected cells was accompanied by increased thick dendrite formation with an enlarged cell body, which is in striking contrast to the control cells, which were rounded and flattened, with few processes. Their growth was significantly slower than that of the control cells. They also demonstrated significantly lower tyrosinase activity and melanogenic potential. We suggest that the enhanced expression of melanoma-associated O-acetyl-GD3 ganglioside may stimulate cellular growth and suppress certain differentiated phenotypes such as dendrite formation but not melanogenesis.

[Studies on decomposed crop residues by FTIR differential analysis]

The decomposing process of corn leaf residues (CLR) was studied by FTIR differential analysis, and the differential spectra were compared with normal spectra. The result showed that the purification process to remove inorganic matters from decomposed CLR could be omitted when differential analysis is used, and the differential spectra were clear and distinct. As far as the studies of decomposed crop residues, the FTIR differential analysis was a convenient and forthright method.

Regulation of the actin cytoskeleton organization in yeast by a novel serine/threonine kinase Prk1p

Normal actin cytoskeleton organization in budding yeast requires the function of the Pan1p/ End3p complex. Mutations in PAN1 and END3 cause defects in the organization of actin cytoskeleton and endocytosis. By screening for mutations that can suppress the temperature sensitivity of a pan1 mutant (pan1-4), a novel serine/threonine kinase Prk1p is now identified as a new factor regulating the actin cytoskeleton organization in yeast. The suppression of pan1-4 by prk1 requires the presence of mutant Pan1p. Although viable, the prk1 mutant is unable to maintain an asymmetric distribution of the actin cytoskeleton at 37 degreesC. Consistent with its role in the regulation of actin cytoskeleton, Prk1p localizes to the regions of cell growth and coincides with the polarized actin patches. Overexpression of the PRK1 gene in wild-type cells leads to lethality and actin cytoskeleton abnormalities similar to those exhibited by the pan1 and end3 mutants. In vitro phosphorylation assays demonstrate that Prk1p is able to phosphorylate regions of Pan1p containing the LxxQxTG repeats, including the region responsible for binding to End3p. Based on these findings, we propose that the Prk1 protein kinase regulates the actin cytoskeleton organization by modulating the activities of some actin cytoskeleton-related proteins such as Pan1p/End3p.

A breast and melanoma-shared tumor antigen: T cell responses to antigenic peptides translated from different open reading frames

Infusion of TIL586 along with IL-2 into the autologous patient with metastatic melanoma resulted in the objective regression of tumor. Here, we report that screening a cDNA library from the 586mel cell line using CTL clones derived from TIL586 resulted in the isolation of a gene, CAG-3 (cancer Ag gene 3). Sequence analysis revealed that CAG-3 encodes an open reading frame identical to NY-ESO-1, which was recently reported to be recognized by autologous serum from a patient with esophageal cancer. Thus, NY-ESO-1 appears to be an immune target for both Ab- and T cell-mediated responses. Significantly, NY-ESO-1-specific CTL clones were capable of recognizing two HLA-A31-positive fresh and cultured breast tumors. To our knowledge, this represents the first direct demonstration that tumor-specific CTL clones can recognize both breast and melanoma tumor cells. A 10-mer antigenic peptide ESO10-53 (ASGPGGGAPR) was identified from the normal open reading frame of NY-ESO-1 based on its ability to sensitize HLA-A31-positive target cells for cytokine release and specific lysis. Interestingly, two additional CTL clones that were sensitized with NY-ESO-1 recognized two overlapping antigenic peptides derived from an alternative open reading frame of the same gene. These findings indicate that CTLs simultaneously responded to two different gene products translated from the normal and alternative reading frames of the same gene. Understanding of this mechanism by which the alternative reading frame is translated may have important implications in tumor immunology.

Transgenic animals with inducible, targeted gene expression in brain

Several inducible gene expression systems have been developed in vitro in recent years to overcome limitations with traditional transgenic mice. One of these, the tetracycline-regulated system, has been used successfully in vivo. Nevertheless, concerns remain about the ability of this system to direct high levels of transgene expression in vivo and to enable such expression to be turned on and off effectively. We report here the generation, using a modified tetracycline-regulated system under the control of the neuron-specific enolase promoter, of several lines of mice that direct transgene expression to specific brain regions, including the striatum, cerebellum, CA1 region of the hippocampus, or deep layers of cerebral neocortex. Transgene expression in these mice can be turned off completely with low doses of doxycycline (a tetracycline derivative) and driven to very high levels in the absence of doxycycline. We demonstrate this tissue-specific, inducible expression for three transgenes: those that encode luciferase (a reporter protein) or DeltaFosB or the cAMP-response element binding protein (CREB) (two transcription factors). The various lines of transgenic mice demonstrate an inducible system that generates high levels of transgene expression in specific brain regions and represent novel and powerful tools with which to study the functioning of these (or potentially any other) genes in the brain.

Development of a retrovirus-based complementary DNA expression system for the cloning of tumor antigens

A new retroviral system has been developed for the generation of a cDNA library and the functional cloning of tumor antigens. These retroviral vectors contain a cytomegalovirus promoter in the 5' long terminal repeat, an extended packaging signal for rapid production of high-titer retroviral particles, and many convenient cloning sites for cDNA library construction. The vesicular stomatitis virus G protein has been used to generate pseudotype retroviral particles to enable efficient viral infection. Using this system, viral titers in the range of 10(6) colony-forming units/ml could be generated routinely, and a high transduction efficiency in human primary cells, including fibroblasts, was achieved. In addition, a new procedure has been devised for screening a retrovirus-based cDNA library without a functional selection. The utility of this system was demonstrated by constructing a retrovirus-based cDNA library and re-isolating the NY-ESO-1 tumor antigen from a cDNA library using an antigen-specific CTL. This approach can facilitate the identification of novel tumor antigens recognized by T cells without knowledge of MHC class I restriction elements and is generally applicable for the isolation of any gene as long as a biological assay is available.

[Study on the relative absorption of food carbohydrate in healthy adults]

The absorption of food carbohydrate was determined with breath hydrogen test (BHT) in healthy adults. When the absorption of lactulose was assumed as 0, the absorption of food carbohydrates were as follows: 100% for rice with ground lean pork; 98% for rice; 85% for bread; 58% for corn and 30% for red potato. The absorption of food carbohydrate was positively related to the oral-colon transit time (OCTT, r = 0.8790) and the peak hydrogen time (PHT, r = 0.6745), and was negatively related to the peak hydrogen value (PHV, r = -0.6468) and to the hydrogen producing percentage (H2 > 1.8 mg/m3, r = -0.8679). The breath hydrogen test can be used in estimating the absorption of food carbohydrate in human body because this method is safe, non-invasive, reproducible and accurate.

Isolation and functional analysis of the promoter of the rat CMP-NeuAc:GM3 alpha2,8 sialyltransferase gene 1

A 2.1-kb 5'-flanking fragment of the rat CMP-NeuAc:GM3 alpha2,8 sialyltransferase (GD3-synthase) gene was cloned by the genomic walking procedure. The promoter activity of the fragment was assessed in F-11 cells by transient transfection and the locations for the basal and maximal promoter activities were defined. Primer extension analysis identified a transcription start site approximately 98 bp upstream of the ATG start codon. DNA sequence analysis of the promoter revealed a number of consensus binding sites for known transcription factors such as SP1, AP1, NFkappaB, C/EBP and TFIID, and a repeat GC-GT sequence motif seen for the formation of Z-type DNA. Both TATA and CCAAT boxes were not found in the promoter. Our results from deletion constructs suggested that both positive and negative cis-acting regulatory regions were present in this TATA-less promoter of the rat GD3-synthase gene.

Infectious disease surveillance in China

A national system of infectious disease surveillance was established in 1959 in China. Now it consists of three subunits, namely, national disease reporting system (NDRS), nationwide disease surveillance points (DSPs), and surveillance network for specific infectious diseases. There are 35 notifiable infectious diseases, which are divided into Classes A, B, and C. The functions of the surveillance include explaining the natural history of infectious diseases, describing the distribution of case occurrence, triggering disease-control effort, monitoring epidemic of infectious diseases during natural disasters, predicting and controlling epidemics and providing the base of policy adjustment.

[Demonstration on Z-D phenomenon in the occurrence of infectious diseases]

A systematic analysis, including retrospective test by means of correlation analysis and extrapolation test was carried out to demonstrate a new hypothesis named Z-D phenomenon which states that the skew of a seasonal case distribution curve of an infectious disease may appear to be the omen of its epidemic trend in the following year. A total number of 353 data sets belong to 17 notifiable infectious diseases in 29 provinces and the whole nation were chosen. Data from retrospective test showed that 91.2% (322/353) of the correlation coefficients of between the skew of the seasonal distribution curve of the previous year and the morbidity variation of its following year were negative. The extrapolation test showed that 68.1% (203/295) of the data sets accorded with the actually epidemic situation at the level of r < -0.5. The results proved the existence of Z-D phenomenon may serve as an indicator for the purpose of forecasting. Using this systematic analysis, we found that Z-D phenomenon was more expressive in viral hepatitis, pertussis, epidemic cerebrospinal meningitis and scarlet fever than in other diseases.

[Preparation and property investigations of nanosized titanium oxide microcrystals]

A naosized TiO2 powder was successfully prepared by the hydrolysis of titanium isopropoxide through sol-gel process. The microstructure of TiO2 powder was investigated by transmission electron microscopy and X-ray diffraction. Both anatase and rutile phases were found in TiO2 powder annealed for 1 hour at 600 degrees C. The characteristics of X-ray photoelectron spectra and infrared spectra could be affected by the size and aggregation state of the microsrystalc constituting the TiO2 powder.

[Spectroscopic study of Langmuir-Blodgett films of octa-4-(hexadecoxy) lanthanium bisphthalocyanine]

The surface pressure/molecular area isotherms ( pi approximately A ) of lanthanium bisphthalocyanine were investigated, showing an edge-on molecular orientation of the macrocycle rings on the water subphase. Langmuir-Blodgett films of this compound were prepared and characterized using IR, UV-vis absorption spectroscopy.