Loss of heterozygosity in multistage carcinogenesis of esophageal carcinoma at high-incidence area in Henan Province, China

AIM: Microsatellites are the repeated DNA sequences scattered widely within the genomes and closely linked with many important genes. This study was designed to characterize the changes of microsatellite DNA loss of heterozygosity (LOH) in esophageal carcinogenesis. METHODS: Allelic deletions in 32 cases of matched precancerous, cancerous and normal tissues were examined by syringe microdissection under an anatomic microscope and microsatellite polymorphism analysis using 15 polymorphic markers on chromosomes 3p, 5q, 6p, 9p, 13q,17p, 17q and 18q.RESULTS: Microsatellite DNA LOH was observed in precancerous and cancerous tissues, except D9S1752. The rate of LOH increased remarkably with the lesions progressed from basal cell hyperplasia (BCH) to squamous cell carcinoma (SCC) (P＜0.05). Three markers, D9S171, D13S260 and TP53, showed the highest incidence of LOH (＞60%). LOH loci were different in precancerous and cancerous tissues. LOH in D3S1234 and TP53 was the common event in different lesions from the same patients. CONCLUSION: Microsatellite DNA LOH occurs in early stage of human esophageal carcinogenesis, even in BCH. With the lesion progressed, gene instability increases, the accumulation of this change may be one of the important mechanisms driving precancerous lesions to cancer.

MODIFIED CLT-DOMAIN MOTION ESTIMATION BASED ON PHASE CORRELATION

In this paper, a Modified Complex Lapped Transform domain Motion Estimation (MCLT-ME) method to estimate the motion of video sequence is proposed. The proposed method is based on phase correlation of current window region and corresponding window region, and provides a significant improvement in motion estimation.

Establishment of Diagnostic Criteria Using EBNA1 IgA Antibody Levels in a High-Risk Area for Nasopharyngeal Carcinoma

OBJECTIVE The EBNA1 IgA antibody level of normal and NPC subjects in a high incidence area were analyzed for new diagnostic criteria to improve diagnosis. METHODS A total of 780 normal and 104 NPC sera were tested for EBNA1 IgA antibody levels by ELISA. Two diagnostic criteria were obtained from sensitivity and specificity data: 1) lower equivocal limit (rOD =1.10) where sensitivity = 95%; and 2) upper equivocal limit (rOD=1.85) where specificity = 95%. RESULTS The range and distribution of EBNA1 IgA antibody levels are broad with those of normal subjects (0.093-4.726, mean = 0.850 ± 0.637) overlapping those from NPC subjects (0.235-3.721, mean = 2.241 ± 0.875). However, NPC subjects did exhibit significantly higher antibody levels (t = 18.5, P<0.001). Based on the diagnostic criteria, 3 diagnostic categories were established: ① Positive; ② Suspected Positive; and 3) Negative. The percentage of NPC subjects falling into these 3 diagnostic categories were 75.13%, 17.44% and 7.44%, respectively and of normal subjects, 4.81%, 17.31%, 77.88% respectively. CONCLUSION Due to the broad distribution and overlapping of antibody levels between normal and NPC subjects in a high incidence area, it is important to have diagnostic criteria that will categorize those with equivocal results to minimize misdiagnosis. The 3 diagnostic categories established in this study will enhance detection and help physicians in their clinical diagnosis.

Mitosis and microtubule organizational changes in rice root-tip cells

The pattern of change of the microtubule cytoskele-ton of the root-tip cells of rice during mitosis was studied using immunofluorescence technic and confocal laser scanning microscopy. All the major stages of cell division including preprophase, prophase, metaphase, anaphase and telophase were observed. The most significant finding was that in the preprophase cells microtubules radiating from the nuclear surface to the cortex were frequently seen. During development these microtubules became closely associated with the preprophase band and prophase spindle indicating that the microtubules radiating from the nuclear surface, the preprophase band and the prophase spindle were structurally and functionally closely related to each other. Granule-like anchorage sites for the radiating microtubules at the nuclear surface were often seen and the possibility that these granule-like anchorage sites might represent the microtubule organizing centres was discussed.

Untraceable partially blind signature based on DLOG problem

This paper proposes a new untraceable Partially Blind Signature scheme which is a cross between the traditional signature scheme and the blind signature scheme. In this proposed scheme, the message M that the signer signed can be divided into two parts. The first part can be known to the signer (like that in the traditional signature scheme) while the other part cannot be known to the signer (like that in the blind signature scheme). After having signed M, the signer cannot determine if he has made the signature of M except through the part that he knows. We draw ideas from Brands' 'Restricted Blind Signature' to solve the Untraceable Partially Blind Signature problem. Our scheme is a probabilistic signature scheme and the security of our Untraceable Partially Blind Signature scheme relies on the difficulty of computing discrete logarithm.

Potent antitumoral effects of a novel gene-viral therapeutic system CNHK300-mEndostatin in hepatocellular carcinoma

The expression of therapeutic gene and its anti-tumor effects will beaugmented and a synergism of oncolytic virus with the therapeutic gene is speculated. This study wasundertaken to assess the anti-tumor effects of a novel gene-viral therapeutic systemCNHK300-mEndostatin ( CNHK300-mE) in hepatocellular carcinoma (HCC). A novel gene-viral therapeuticsystem named CNHK300-mE was constructed using the human telomerase reverse transcriptase (hTERT)promoter to drive the expression of the adenovirus El A gene and cloning the therapeutic gene mouseendostatin into the adenovirus genome. By the tissue culture infectious dose 50 (TCID50) method andcytoviability assay, the replicative and cytolytic capabilities of CNHK300-mE in two HCC lines (HepGII and Hep3B) and one normal cell line ( MRC-5 ) were analyzed, and the transgene expressions ofmouse endostatin in vitro and in vivo were detected by Western blotting and ELISA assay. Tumorgrowth suppression and anti-angiogenesis effects in vivo were investigated using nude micexenografts model derived from SMMC-7721 HCC cells. The 3296-fold replicating capacity of CNHK300-mEin HCC cell lines versus in the normal cell line at 96 hours post infection and the 25 -foldeffective dose for killing 50% cells ( ED50) in the normal cell line versus HCC cell lines, whichwere both superior to ONYX-015, were observed. Tumor growth suppression of CNHK300-mE superior toeither Ad-mE or ONYX-015 was demonstrated (P < 0. 01) and the anti-angiogenic effects in vivosuperior to Ad-mE were also observed with immunohistochemical staining of von Willebrand factor. Incomparison with non-replicative adenovirus Ad-mE, the transgene expression of mE mediated byCNHK300- in vivo (P<0.05). Being capable of replicating in and lysing the telomerase-positive HCCcells and mediating effective expression of the therapeutic gene in vitro and in vivo, the novelgene-viral therapeutic system CNHK300-mE is potentially effective in the treatment of HCC.

High-quality hydrocarbon source rock in the Paleogene sequence of the Ping Chau Formation, Hong Kong

Although petroleum exploration is being con- ducted in the Hong Kong region, high-quality hydrocarbon source rocks have never been found in this area. The Ping Chau Formation is only Mesozoic-Cenozoic sedimentary rock exposed in Hong Kong and its surrounding areas. The hydrocarbon source rock of the Ping Chau Formation is very rich in organic matters, which has an average total organic carbon (TOC) of 1.9% and chloroform bitumen “A” range from 0.14% to 0.24%. The total hydrocarbon content varies from 880 to 1800 ppm and the transformation ratio is spe- cific from 5 to 9. The index of pyrolytic hydrogen is up to about 600 mgHC/gTOC. These data demonstrate the char- acteristics of the high-quality hydrocarbon source rock. The lamalginite is the major maceral of the source rock of the Ping Chau Formation, and geochemical characteristics also suggest that the organic materials of the source rock are of type I and type II1, with abundant gammacerane, γ, β-caro- tane and C24 tetracyclic terpane, which indicate that it was formed in the salt water and brackish water sedimentary environment, and the source rock has evolved into a mature phase. The organic inclusions are found within calcite veins in cracks of the source rock, indicating that hydrocarbon has been generated and a secondary migration has happened. The source rock in the Ping Chau Formation is about 200—300 m thick, thus having considerable hydrocarbon potential. The discovery of the high quality hydrocarbon source rock in the Ping Chau Formation will certainly pro- vide insight on hydrocarbon resource exploration in the South China Sea area.