Biomedical subjects

S S Li

Publications and source records attributed to S S Li.

At least 19 recordsLinked to original sources

PubMed2001

Lactate dehydrogenase genes of caiman and Chinese soft-shelled turtle, with emphasis on the molecular phylogenetics and evolution of reptiles.

L-Lactate dehydrogenase (LDH) cDNAs encoding for LDH-A(4) (muscle) and LDH-B(4) (heart) isozymes from caiman (Caiman crocodilus apaporiensis) belonging to the order Crocodilia and Chinese soft-shelled turtle (Pelodiscus sinensis) belonging to the order Chelonia were sequenced. The phylogenetic relationships of the newly determined cDNA and their deduced protein sequences, as well as the previously published sequences of vertebrate LDH isozymes, were analyzed by various phylogenetic tree construction methods. These results indicated that Chelonia is indeed more closely related to Crocodilia. The divergent times between caiman and alligator, turtle and soft-shelled turtle, and Chelonia and Crocodilia were estimated to be approximately 36, 100 and 177 million years, respectively.

Alligators and Crocodiles↗

PubMed2001

Quantum computing.

Quantum computing is a quickly growing research field. This article introduces the basic concepts of quantum computing, recent developments in quantum searching, and decoherence in a possible quantum dot realization.

Journal Article↗

PubMed2001

Environmental impact of radionuclide migration in groundwater from a low-intermediate level radioactive waste repository.

The radionuclide migration from a certain Chinese repository with low-intermediate level radioactive solid waste is studied. The migration in groundwater is analyzed and computed in detail. Under presumption of normal releasing, or the bottom of the repository has been marinated for one month with precipitation reaching 600 mm once and a 6 m aerated zone exists, a prediction for 7 radionuclides is conducted. It shows that the aerated zone is the primary barrier for migration. The migration for radionuclides 60Co, 137Cs, 90Sr, 63Ni, etc. will be retarded in it within 500 years. The concentration of 239Pu will be decreased by amount of 6 order. Only 3H and 14C can migrate through the aerated zone. The radionuclides that go through the aerated zone and enter the aquifer will exist in spring, stream and sea. Based on this, the intake dose by residents in different age group resulting from drinking contaminated spring water, eating seafood is calculated. The results showed that the impact of the repository to the key resident group is lower than the limit in national repository regulation standard. This complies with the repository management target.

Air↗

PubMed2001

[Content-based medical image retrieval].

At first, the concept of medical image retrieval based on contents is here illustrated. Then, features of medical image are analyzed. Among them, gray histogram method, texture method, shape method are discussed, and the compression method is emphasized. Finally, the challenges in medical image retrieval are presented before us in the paper.

Algorithms↗

PubMed2001

[The trends and preventive strategies of esophageal cancer in high-risk areas of Taihang Mountains, China].

OBJECTIVE: To analyze and predict the trends of incidence and mortality rates of esophageal cancer in areas of Taihang Mountains, and explore the strategies for facilitating the reduction of the incidence and mortality of esophageal cancer. METHODS: The data were collected from Linxian and Cixian Counties registries between 1988-1997. The trends of the incidence and mortality rates for esophageal cancer had been fitted and predicted by the model of BP (Back Propagation) Neural Networks. Then Linqi Xiang in Linxian County was taken as an example, to determine the power for reducing incidence and mortality of esophageal cancer using endoscopic technology as an early detection and treatment method. RESULTS: There were slowly declining trends for both incidence and mortality rates during past 10 years in Taihang Mountains. The predicting rates of the esophageal cancer incidence in 2,002 are 115. 70/100,000 for male and 79.88/100,000 for female; mortality rates are 94.00/100,000 and 56.29/100,000 respectively. Both incidence and mortality rates a still in high level. But when using endoscopic technology as an early detection and treatment method, the incidence rate is nearly 1/3 of a control group and the power is 88.30% at the end of eight years. The mortality rate is 1/4 of the control group and power is 89.44% after five years intervention (both powers based on 0.05 significant levels). CONCLUSIONS: The incidence and mortality rates for esophageal cancer are still on high levels in Taihang Mountains. We should continue to enhance our preventive effort there. After using endoscopic technology as an early detection and treatment method, the incidence and mortality rates will be decreased markedly during 5 to 8 years. It is recommended to implement a large-scale secondary prevention strategy in these areas.

China↗

PubMed2000

cDNA cloning of pig testicular lactate dehydrogenase-C, thermal stability of the expressed enzyme, and polymorphism among strains.

Pig testicular lactate dehydrogenase-C (LDHC) cDNA was cloned and sequenced. The deduced sequence of 332 amino acids from pig LDHC shows 73% and 67% identity with that of pig LDHA (muscle) and LDHB (heart) respectively, whereas pig LDHA and LDHB isozymes shows 74% sequence identity. Pig and mouse LDHC cDNAs were subcloned into bacterial expression vector, and the expressed pig LDHC isozyme was shown to be as thermally stable as mouse LDHC isozyme. Pig genomic DNAs from Chinese Meishan, English Yorkshire, Danish Landrace and American Duroc were shown to exhibit polymorphic sites for restriction enzymes EcoRI, BamHI and PstI.

Animals↗

PubMed2000

Transfer of foreign gene to giant freshwater prawn (Macrobrachium rosenbergii) by spermatophore-microinjection.

We developed a spermatophore-microinjection (SMI) technique that allows exogenous DNA fragments to be transferred easily into the giant freshwater prawn (Macrobrachium rosenbergii), an important aquacultural shellfish and aquatic invertebrate model. From 28 to 1, 000 ng of the circular plasmid pGL, in a total volume of 1 microl, were directly microinjected into spermatophores. Fertilization and hatching of prawns created with SMI were completed in vivo. Fertilization and hatching rates in the SMI treatments did not differ from those of the untreated control group. The genomes of free swimming, SMI-created larvae (21 days after fertilization) were analyzed using PCR and Southern blot analyses. A product with a molecular mass of 680 bp was amplified. It corresponded to amplifications of pGL, and Southern blot analysis revealed that the amplified band was positive. The gene transfer rate was primarily dependent on the concentration of DNA during SMI. The higher the concentration of pGL, the higher the rate of gene transfer. PCR and Southern blot analyses detected the existence of foreign DNA in 16 of 23 samples (70%) of genomic DNA isolated from hatched larvae in the 750 ng pGL SMI treatment. SMI, described here for the first time, is the simplest and most efficient method for mass producing transgenic giant freshwater prawns.

Animals↗

PubMed2000

Structure and function of the Groucho gene family and encoded transcriptional corepressor proteins from human, mouse, rat, Xenopus, Drosophila and nematode.

A gene family of the Groucho, TLE, ESG and AES proteins has been characterized from Drosophila, nematode, Xenopus, mouse, rat and human, and their structural relationships have been analyzed. The genomic organization of nematode ESG, human and mouse AES genes has been determined, and the expression of ESG and AES genes from Xenopus and human has been analyzed. The Groucho, TLE and ESG proteins all share a similar structure, consisting of a conserved amino-terminal domain, a variable middle region, and highly conserved carboxyl-terminal WD-40 repeats. The Drosophila Groucho transcriptional corepressor protein has been shown to interact with the DNA-binding bHLH domain of Enhancer of split, Hairy and Deadpan proteins, which proteins are involved in neurogenesis, segmentation and sex-determination, respectively. Human TLE1 protein has been demonstrated to interact with mammalian AML1 protein, which regulates hematopoiesis and osteoblast differentiation. The AES proteins from human, mouse, rat and Xenopus exhibit strong similarity to the amino-terminal domain of Groucho proteins; however, the biological function remains to be elucidated.

Amino Acid Sequence↗

PubMed2000

Familial breast cancer in southern Taiwan.

The purpose of this study is to evaluate whether there are pathobiologic differences and differences in overall rates survival between familial and non-familial breast cancer patients in Taiwan. A retrospective study was performed evaluating 76 familial breast cancer patients in 69 families, which included two BRCA1 related cases and six BRCA2 related cases. Patients were compared with 425 non-familial sporadic cases. Familial breast cancer patients had similar ages and stages as non-familial patients (mean, 46.6 years vs 48.9 years, p = 0.306). However, the familial breast cancer patients with BRCA1 and BRCA2 related cases presented at lower stages (p = 0.034) and younger ages than non-familial patients (mean, 45.1 years vs 48.9 years P = 0.042). The occurrence of infiltrating ductal carcinoma and lobular carcinoma in situ was not significantly different in the two groups. Mucinous carcinoma was represented with 6.7% (4/76) and 1.3% (1/76) medullary carcinoma. The overall grade of familial breast cancer, including BRCA1 and BRCA2 related cases in 8 infiltrating ductal carcinoma, was significantly higher than that of controls. The mean follow up was 4.5 years for familial breast cancers. Five- and 10-year overall survival rates were 69% and 61% for those with a family history, compared with 86% and 64% for those in the control group (p = 0.644). There were no statistically significant differences in disease-free survival rates between the two groups at 5 or 10 years (69% vs 78% in 5 years; 48% vs 58% in 10 years) (p = 0.862). Despite the younger ages and earlier stages at presentation in familial breast cancer patients with BRCA1 and BRCA2 related cases, the familial breast cancer patients had higher grade patholobiologic characteristics, but similar prognoses when compared with sporadic breast cancer patients. Owing to the limited number of familial cases in this study, more cases and longer follow up are needed.

BRCA2 Protein↗

PubMed2000

[Flavonoids and anthraquinone from Dioscorea bulbifera L].

OBJECTIVE: To study the chemical constituents of Dioscorea bulbifera. METHOD: Column chromatography with silica gel was employed for the isolation and purification of constituents. The structures were elucidated by UV, IR, MS, 1H NMR and 13C NMR analyses. RESULT: Three compounds were obtained and elucidated as 3,7-dimethoxy-5,4'-dihydroxyflavone; 3,7-dimethoxy-5,3',4'-trihydroxyflavone and emodin. CONCLUSION: These compounds were separated from D. bulbifera for the first time.

Anthraquinones↗

PubMed1999

Ecological study on the risks of esophageal cancer in Ci-Xian, China: the importance of nutritional status and the use of well water.

Our purpose was to determine the environmental risks in the development of esophageal cancer in Ci-Xian, which has one of the highest incidences of esophageal cancer in China. The subjects included 404, 352 and 400 inhabitants living in high-, medium-, and low-incidence areas of esophageal cancer, as well as 301 esophageal cancer patients. A food intake-frequency survey using a 7-day weighted inventory questionnaire was conducted on these individuals. Questions on occupation, working conditions, income per year, family disease history, medical complaints, and demographic features were also included in the questionnaire. The levels of nitrogen compounds in selected samples of well water were also measured in each of the 3 areas. Clear-cut differences in food intake were seen among inhabitants living in the 3 different areas, suggesting that regional differences in nutritional styles do exist. In both males and females, the intake of potatoes, fruit, vegetables, and meat were significantly lower in inhabitants living in the high-incidence area than in the other inhabitants, much the same as that of cancer patients. A low intake of carotene, and vitamins A and C was also seen in populations living in the high-incidence area of esophageal cancer. The well water polluted with nitrogen compounds was significantly related to the high incidence of esophageal cancer. In contrast, tobacco, alcohol consumption, and the intake of pickled vegetables and moldy foods did not relate to the different incidence rates. Our results suggest that low intake of fruit, vegetables, potatoes and meat, and the quality of well water may be important factors in the development of esophageal cancer in Ci-Xian.

Adult↗

PubMed1999

Molecular evidence for a clade of turtles.

Although turtles have been generally grouped with the most primitive reptile species, the origin and phylogenetic relationships of turtles have remained unresolved to date. To confirm the phylogenetic position of turtles in amniotes, we have cloned and determined the cDNA sequences encoding for skink lactate dehydrogenase (LDH)-A and LDH-B, snake LDH-A, and African clawed frog LDH-A; four alpha-enolase cDNA sequences from turtle, alligator, skink, and snake were also cloned and determined. All of these eight cDNA sequences, as well as the previously published LDH-A, LDH-B, and alpha-enolase of mammals, birds, reptiles, and African clawed frog, were analyzed by the phylogenetic tree reconstruction methods of neighbor-joining, maximum parsimony, and maximum likelihood. In the phylogenetic analyses, the turtle was found to be closely related to the alligator. Also, we found that the turtle had diverged after the divergence of squamates and birds. This departs from previous hypotheses of turtle evolution and further suggests that turtles are the latest of divergent reptiles, having been derived from an ancestor of crocodilian lineage within the last 200 million years.

Alligators and Crocodiles↗

PubMed1999

Molecular characterization of germline mutations in the BRCA1 and BRCA2 genes from breast cancer families in Taiwan.

A total of 18 families with multiple cases of breast cancer were identified from southern Taiwan, and 5 of these families were found to carry cancer-associated germline mutations in the BRCA1 and BRCA2 genes. One novel cryptic splicing mutation of the BRCA1 gene, found in two unrelated families, was shown to be a deletion of 10 bp near the branch site in intron 7. This mutation causes an insertion of 59 nucleotides derived from intron 7 and results in a frameshift, leading to premature translational termination of BRCA1 mRNA in exon 8. Deletions of 2670delC, 3073delT and 6696-7delTC in the BRCA2 gene were found in three other breast cancer families. All three deletions are predicted to generate frameshifts and to result in the premature termination of BRCA2 protein translation. Several genetic polymorphisms in both BRCA1 and BRCA2 genes were also detected in this investigation.

Adult↗

PubMed1998

Identification and characterization of the SMT3 cDNA and gene encoding ubiquitin-like protein from Drosophila melanogaster.

A SMT3 cDNA encoding ubiquitin-like protein from Drosophila melanogaster was isolated and sequenced. Drosophila SMT3 genomic DNA was amplified by polymerase chain reaction, and its nucleotide sequence was found to be identical to that of the cDNA, indicating the absence of intron in its protein coding region. The sequence of 90 amino acids of Drosophila SMT3 exhibited 55%, 73%, 70% and 52% identity to yeast SMT3, human SMT3A, SMT3B and SMT3C protein.

Amino Acid Sequence↗

PubMed1998

Characterization of mouse ubiquitin-like SMT3A and SMT3B cDNAs and gene/pseudogenes.

Mouse SMT3A and SMT3B cDNAs encoding ubiquitin-like proteins of 110 and 95 amino acids, respectively, were isolated and sequenced. The sequence of the first 92 amino acids (ending with the conserved Gly-Gly) of mouse SMT3A exhibited two differences at amino acid no. 38 and 76 in comparison with that of human SMT3A. The C-terminal 18 amino acid sequence of mouse SMT3A was completely different from the C-terminal 11 amino acid sequence of human SMT3A. Mouse and human SMT3B were identical for a sequence of 95 amino acids. Mouse SMT3A genomic DNAs were amplified by polymerase-chain-reaction and sequenced. The nucleotide sequence of a PCR-amplified SMT3A genomic DNA fragment was found to be identical to that of SMT3A cDNA, indicating the absence of intron(s) in its protein coding region. Another genomic DNA fragment of 1,531 nucleotides, containing 7% differences from that of cDNA, is unable to encode a functional protein, and thus, it is a SMT3A processed pseudogene. Three mouse SMT3B processed pseudogenes were cloned and sequenced. The genuine mouse SMT3B gene has not yet been isolated. Mouse SMT3A transcript of 1.8 kb was predominantly expressed in most tissues, while SMT3B transcript of 1.0 kb was abundantly present in all tissues analyzed. A family of ubiquitin-like proteins was recently discovered. One distinguishing feature of ubiquitin and ubiquitin-like proteins is the capacity to conjugate with other proteins post-translationally. The ubiquitin-like proteins are cleaved endoproteolytically after a diglycine sequence, corresponding to the C-terminal Gly75-Gly76 of ubiquitin. The cleavage activates the molecule for conjugation. The yeast SMT3 gene was originally identified as a suppressor of mutations in MIF2 gene, which encodes an essential protein binding to the A+T-rich CDEII region of centromere DNA (1). Studies using temperature-sensitive mutants showed that the loss of yeast Mif2 protein function results in chromosome missegregation, mitotic delay, and aberrant microtubule morphologies (2). The yeast Mif2 protein shares at least two regions of similarity with mammalian centromere protein CENP-C, an integral component of active kinetochores (3, 4). Human SMT3A cDNA was identified from the genome sequencing project of chromosome 21 (5). We have cloned human SMT3B (formerly designated as HSMT3) cDNA (6). Human SMT3C protein was independently isolated by several groups and denoted as SUMO-1 (7), GMP1 (8), PICI (9), UBL1 (10), sentrin (11). SUMO-1/GMP1 was found to be covalently linked to the Ran GTPase-activating protein RanGAP1, and attachment of SUMO-1 targets the otherwise cytosolic RanGAP1 to the nuclear pore complex. The modified form of RanGAP1 also appeared to associate with the mitotic spindle apparatus during mitosis (7, 8). PIC1 was shown to interact with the PML component of nuclear multiprotein complex that is disrupted in acute promyelocytic leukemia (9). UBL1 was found to associate with human RAD51/RAD52 proteins involved in DNA recombination and DNA double-strand break repair (10). Sentrin was shown to interact with Fas/APO-1 or the TNF receptor 1 death domain, and the overexpression of sentrin provided protection against both anti-Fas/APO-1 and TNF-induced cell death (11). Here we report the characterization of mouse SMT3A and SMT3B cDNAs, gene/pseudogenes, and mRNA expression.

Amino Acid Sequence↗

PubMed1998

Genomic organization and chromosome localization to band 19p13.3 of the human AES gene: gene product exhibits strong similarity to the N-terminal domain of Drosophila enhancer of Split Groucho protein.

The human Amino Enhancer of Split (AES) gene encodes a protein of 197 amino acids exhibiting strong similarity to the N-terminal domain of Drosophila Enhancer of Split Groucho (ESG) protein. The nucleotide sequence of approximately 12 kb from the human AES gene was determined, and its protein-encoding sequence was shown to be interrupted by six introns. The human AES gene was further localized by fluorescence in situ hybridization to chromosome band 19p13.3 near the transcription factor 3 (TCF3) gene.

Amino Acid Sequence↗

PubMed1998

Trends in food label use associated with new nutrition labeling regulations.

OBJECTIVES: This study compared use of food labels before and after implementation of new Food and Drug Administration regulations in 1994. METHODS: Data were obtained by random-digit-dial surveys of Washington State residents in 1993 (n = 1001) and 1996 (n = 1450). RESULTS: After implementation of the new regulations, usual label use increased significantly, by 8.5 percentage points in women and 11.3 percentage points in men. More respondents looked for information on fat content and fewer failed to use labels because they "take too much time" or "are too hard to understand. CONCLUSIONS: Use of food labels and satisfaction with their content have increased, but 70% of adults still want labels to be easier to understand.

Adolescent↗

PubMed1998

Teleconferencing in endoscopic surgery.

The traditional methods of information dissemination by publication in journals and the classical model of instruction by apprenticeship have not been able to keep pace with the rapid advances in the fields of therapeutic endoscopy and laparascopic surgery. The advances in communications technology have made it possible to transmit images of operative procedures over long distances. In recent years, teaching workshops where procedures are demonstrated in a real-time fashion have become very popular. This article discusses the logistics, limitations, and problems that may be encountered in conducting such workshops.

Journal Article↗