Search PubMed⌕ Search

Biomedical subjects

Kai Li

Publications and source records attributed to Kai Li.

At least 55 records · Page 3Linked to original sources
PubMed2004

[Effect of nandrolone phenylpropionate on hepatic albumin mRNA and granulational alpha 1(I) procollagen mRNA in burned rats].

OBJECTIVE: To assess the mechanism for the effect of nandrolone phenypropionate (NP) on hepatic albumin mRNA and granulational alpha 1(I) procollagen mRNA in burned rats with the aim to underpin the clinical application of anabolic steroids. METHODS: Thirty-two Wistar rats with a deep second-degree cutaneous burn of 20% total body surface area were randomly divided into two groups to receive either 5 mg/kg NP (NP group) or normal saline as placebo(control group) every other day. The expression copy quantities of albumin-mRNA in liver tissue and alpha 1 (I) procollagen mRNA in granulation wound were measured by quantitative fluorescent RT-PCR respectively on the post-burned days 4, 7, 14 and 21. RESULTS: The expression levels of albumin-mRNA and alpha 1 (I) procollagen mRNA in NP group were much higher than those in control group. The 7th and 14th days were the periods in which the albumin-mRNA and alpha 1 (I) procollagen mRNA expression had been increasing obviously (P < 0.01). CONCLUSION: Nandrolone phenylpropionate could effectively up-regulate the expression of albumin-mRNA in liver tissue and the alpha 1 (I) procollagen mRNA in granulation wound.

Albumins↗
PubMed2004

Misoprostol in labour induction of term pregnancy: a meta-analysis.

OBJECTIVE: To evaluate the efficacy and safety of misoprostol in term labour induction. DATA SOURCES: Data from published English and Chinese literatures about misoprostol in term labour induction were identified from Medline and CBMdisk (using the search terms "misoprostol" and "labour induction") before 2001; hand searches of reference lists of original studies and reviews (including meta-analyses) and contact with investigators in this field before 2001. STUDY SELECTION: Studies were included if they had data on misoprostol and labour induction. Altogether 623 articles were found and 124 were admitted, including 19,287 cases. DATA EXTRACTION: Data were collected on efficacy and incidence of side-effects of misoprostol and oxytocin. Data were checked for consistency within the published articles and converted into a standard format for incorporation into a central database. DATA SYNTHESIS: The average successful induction rate, rates of caesarean section; incidence of tachysystole, hypertonus of uterus and precipitous labour, and rates of meconium stained amniotic fluid between the misoprostol and oxytocin groups were significantly different (P < 0.05). There were no significant differences between the two groups concerning the average interval from the administration of misoprostol and oxytocin to the onset of labour, duration of the total stage of labour, incidence rate of foetal distress, neonatal asphyxia (1-minute Apgar score < and= 7), postpartum haemorrhage or amount of blood loss in postpartum. CONCLUSIONS: Misoprostol is a superior agent over oxytocin on the induction of term labour, but its application might increase the risk of precipitous labour, abnormal uterine contractions or meconium stained amniotic fluid. Therefore, the dosages and regimens of the agent need further investigation.

Female↗
PubMed2004

[Visualization of the parapharyngeal space of the Chinese visible human].

OBJECTIVE: To build digitized visible model of the parapharyngeal space(PPS) of Chinese visible human. METHOD: Cross-sectional images from the Chinese visible human data set were reviewed and the structures of the parapharyngeal space were confirmed on a section-by-section basis. Three-dimensional computer reconstructions of the parapharyngeal space and surrounding structures were generated from these data using PC and imaging software. RESULT: The three-dimensional reconstructed images displayed perfectly the anatomical relationships of the parapharyngeal space, parotid, muscles, mandible and vessels. All reconstructed structures can be represented individually or jointly, any diameter and angle of the structures reconstructed could be measured conveniently. CONCLUSION: The Chinese visible human data set can provide complete and accurate data. The digitized model of the parapharyngeal space and its surroundings offer unique insights into the complex anatomy, and provide morphological data for image diagnosis and operation of the parapharyngeal space.

Adipose Tissue↗
PubMed2004

[Effects of nandrolone phenylpropionate on fibroblasts after injury in rats].

OBJECTIVE: To explore the effects of nandrolone phenylpropionate (NP) on fibroblasts after injury in rats. METHODS: Thirty-two Wistar rats with a deep second-degree scald injury and 20% total body surface area were randomly divided into two groups to receive either 5 mg/kg NP (NP group) or normal saline as placebo (control group) every other day. Integrated optical density (IOD) of androgen receptor (AR) and mRNA expression level of alpha1 (I) procollagen were measured by immunohistochemistry and quantitive fluorescent RT-PCR individually on the post-burn days 4, 7, 14 and 21. Fibroblasts were isolated from granulation tissue of a Wistar rat and were cultured in RPMI1640 with the addition of NP at different concentrations. Cell viability of fibroblasts was measured by MTT test, and the proliferative index, by flow cytometry (FCM). RESULTS: (1) Compared with the A value of the concurrent control group, higher A values were seen in NP groups containing different concentrations of NP, and significant difference of proliferative index was observed in NP group, P<0.05. (2) The expression of alpha1 (I) procollagen mRNA in NP groups was much higher than that in control groups. A significant difference between the two groups was noted on the post-burn days 7, 14 and 21, P<0.05, but no difference was seen on day 4. (3) The density of AR on fibroblasts in NP group was higher than that in control group at each time point. And a positive correlation between the expression of alpha1 (I) procollagen mRNA and the quantity of AR on fibroblasats was confirmed (r = 0.836). CONCLUSION: Nandrolone phenylpropionate could promote fibroblast replication, increase the mRNA level of alpha1 (I) procollagen and enhance the density of AR on fibroblasts.

Anabolic Agents↗
PubMed2004

[Visualization and thin sectional anatomy of the laryngeal cartilages].

OBJECTIVE: To establish digitized visible model of the laryngeal cartilages of the visible human, providing morphological data for image diagnosis and laryngectomy. METHODS: Cross-sectional images of fresh tissues from the Chinese visible human data set were reviewed, and the laryngeal cartilages structures data were used, the data was on a section-by-section basis. Three-dimensional computer reconstructions of the laryngeal cartilages were generated from these data by surface rendering on a SGI workstation. RESULTS: The digital images from the visible human offer unique insights into the complex anatomy and ossification of the laryngeal cartilages, the quality of the computerized 3D-reconstructed images was distinct and perfect. CONCLUSIONS: The visible human data set can provide complete and accurate data The digitized model of the laryngeal cartilages offer unique insights into the laryngeal anatomy, could be used for resident education, rehearsal of an unfamiliar surgery and for developing a new surgical approach.

Adult↗
PubMed2004

[Preliminary study on the applying value of two measurements for bone age in the cases of minors].

OBJECTIVE: To research the connection of the minor's bone age and chronological age and age for penal responsibility, to discuss the application of Gu's Atlas and Li Guozhen's Percent Numeration to measure the bone age in the cases of immature criminals and the applying value. METHODS: 33 healthy youths, 12-19 years old, were selected, whose left wrists were photographed with X-rays. According to the radiographic appearance of the maturity indicators, the bone age of every person was determined respectively by the Gu's Atlas and Li Guozhen's Percent Numeration, and then compared with his/her chronological age. CMH test and Pearson test were used to evaluate precision and accuracy on concluding the immature age for penal responsibility. RESULTS: Li Guozhen's Percent Numeration was more precise than Gu's Atlas on extrapolating the chronological age of the youth, P<0.005. On extrapolating the age for penal responsibility, the accuracy of the former was 90.91%, and the latter was 78.79%, but the statistic result did not show significant difference (P>0.1). CONCLUSION: Both measurements can apply in determining the criminal cases of immature youths.

Adolescent↗
PubMed2003

The roles of birth inputs and outputs in predicting health, behaviour and test scores in early childhood.

The goal of this study is to address directly the predictive value of birth inputs and outputs, particularly birth weight, for measures of early childhood development in a simultaneous equations modelling framework. Strikingly, birth outputs have virtually no structural/causal effects on early childhood developmental outcomes, and only maternal smoking and drinking during pregnancy have some effects on child height. Not surprisingly, family child-rearing environment has sizeable negative and positive effects on a behavioural problems index and a mathematics/reading test score, respectively, and a mildly surprising negative effect on child height. Despite little evidence of a structural/causal effect of birth weight on early childhood developmental outcomes, our results demonstrate that birth weight nonetheless has strong predictive effects on early childhood outcomes. Furthermore, these effects are largely invariant to whether family child-rearing environment is taken into account. Family child-rearing environment has both structural and predictive effects on early childhood outcomes, but they are largely orthogonal and in addition to the effects of birth weight.

Birth Weight↗
PubMed2003

On-off regulation of 3' exonuclease excision to DNA polymerization by Exo+ polymerase.

The role of 3' exonuclease excision in DNA polymerization was evaluated in primer extensions using 3' allele-specific primers that had exonuclease-digestible and exonuclease-resistant 3' termini. With exonuclease-digestible unmodified 3' mismatched primers, the exo+ polymerase yielded template-dependent products. Using exonuclease-resistant 3' mismatched primers, no primer-extended product resulted from exo+ polymerase. As a control, polymerase without proofreading activity yielded primer-dependent products from 3' mismatched primers. These data indicated that a successful removal of the mismatch is required for DNA polymerization from the 3' mismatched primers by exo+ polymerase. In addition to the well-known proofreading from this mismatch removal, the premature termination in DNA polymerization, due to the failure of the efficient removal of the mismatched nucleotides, worked as an off-switch in maintaining the high fidelity in DNA replication from exo+ polymerase.

Base Sequence↗
PubMed2003

On/off switch mediated by Exo+ polymerases: experimental analysis for its physiological and technological implications.

The potential physiological role and technological application of the premature termination of DNA polymerization through the off-switch of exo+ polymerases were studied using 3' phosphorothioate-modified or unmodified primers with single base mismatch distal to the 3' terminus. With exonuclease-digestible unmodified primers, a gradient premature termination of DNA polymerization was observed when amplified with exo+ polymerases. With 3' allele specific phosphorothioate-modified primers, an efficient off-switch effect occurred in the discrimination of a single nucleotide polymorphism when directly using genomic DNA. Clearly, the off-switch of exo+ polymerases is useful in biomedical research.

Alleles↗
PubMed2003

Controllable diastereoselective cyclopropanation. Enantioselective synthesis of vinylcyclopropanes via chiral telluronium ylides.

Novel chiral telluronium salts 1 are designed for asymmetric synthesis of 1,3-disubstituted 2-vinylcyclopropanes. The allylides, generated in situ from the corresponding telluronium salt in the presence of different base, reacted with alpha,beta-unsaturated esters, ketones, and amides to afford cis-2-silylvinyl-trans-3-substituted or trans-2-silylvinyl-trans-3-substituted cyclopropane derivatives with high diastereoselectivity and excellent enantioselectivity in good to high yields. Thus, either one of the two diastereomers could be enantioselectively synthesized at will just by the choice of LiTMP/HMPA or LDA/LiBr. The first examples of catalytic ylide reaction for enantioselective synthesis of 1,3-disubstituted 2-vinylcyclopropanes with high distereoselectivity is also achieved.

Alkenes↗
PubMed2003

Wnt pathway activation in mesothelioma: evidence of Dishevelled overexpression and transcriptional activity of beta-catenin.

Malignant pleural mesothelioma is a relatively uncommon and yet incurable tumor. The pathogenesis of mesothelioma remains poorly understood. This study evaluated the role of Wnt signaling in mesothelioma. Western blot analysis was conducted to confirm the expression of Dishevelled (Dvl) and cytosolic beta-catenin in matched autologous tissue samples (tumor and normal pleura), malignant pleural effusions, and in established mesothelioma cell lines LRK1A, REN and H513. Thirteen of 15 mesotheliomas examined showed consistent overexpression of Dvl and increased cytosolic beta-catenin levels as compared with controls. To evaluate T-cell factor (Tcf)-dependent transcriptional activity of beta-catenin, luciferase assays were conducted. Fresh mesothelioma cells (effusion derived), as well as LRK1A, REN, and H513 cell lines showed a significant fold increase (1.5-2.4-fold, P < 0.01) in Tcf-dependent transcriptional activity of beta-catenin. To evaluate the biological significance of Dvl function in mesothelioma, a PDZ domain deletion mutant (DeltaPDZ-Dvl) was created and stably transfected into LRK1A, REN, and H513. The effect of DeltaPDZ-Dvl on mesothelioma growth was assayed in vitro (colony formation assay in soft agar) and in vivo (s.c. implantation in athymic mice NCRNU-M). In mesothelioma cells tested, DeltaPDZ-Dvl-mediated inhibition of Dvl decreased cytosolic beta-catenin levels, diminished Tcf-mediated transcription, and suppressed tumorigenesis of LRK1A and REN in vitro and in vivo. DeltaPDZ-Dvl also down-regulated expression of c-myc in REN and COX-2 in H513. Our data suggest that in malignant pleural mesothelioma, Wnt signaling is activated through Dvl overexpression and downstream signaling through beta-catenin. Inhibition of this signaling leads to significant antitumor effects. These results demonstrate Dvl overexpression in human cancer and, specifically, that Wnt signaling plays a role in mesothelioma pathogenesis. These data offer possible new avenues for therapeutic intervention.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Creation of the Chinese visible human data set.

The United States Visible Human Project (VHP) created a digital image data set of complete human male (data acquisition finished in November 1994) and female (data acquisition finished in December 1995) cadavers in magnetic resonance imaging (MRI), computed tomography (CT), and anatomical (anatomic serial section) modes. VHP aroused worldwide enthusiasm for Visible Human Research (VHR), and the data set is being used in a variety of research and educational domains. The Visible Korean Human (VKH) male was produced in March 2001. To accelerate worldwide VHR and to promote virtual anatomy as a revolutionary break with conventional anatomy, more visible human data sets representative of different populations of the world are in demand. The Chinese Visible Human (CVH) male (created in October 2002) and female (created in February 2003) project achieved greater integrity of images, easier blood vessel identification, and were free of organic lesion (unlike the other visible human projects). We performed data acquisition, three-dimensional (3D) reconstruction, and visualization with improved technology to create CVH male and female. CVH is the first volumetric data representing a complete normal adult human male and female of an Asian population. This article presents the history of Chinese Visible Human cadavers and the methods and technology used to produce the data set.

Anatomy, Cross-Sectional↗
PubMed2003

Different applications of polymerases with and without proofreading activity in single-nucleotide polymorphism analysis.

With the completion of the human genome project, single-nucleotide polymorphisms (SNPs) have become the focus of intense study in biomedical research. Polymerase-mediated primer extension has been employed in a variety of SNP assays. However, these SNP assays using polymerase without proofreading function are compromised by their low reliability. Using a newly developed short amplicon harboring restriction enzyme site, EcoR-I, we were able to compare the single-base discrimination abilities of polymerases with and without proofreading function in primer extension in a broad range of annealing temperatures. Thermodynamic analysis demonstrated a striking single-nucleotide discrimination ability of polymerases with proofreading function. Using unmodified 3'-end allele-specific primers, only template-dependent products were generated by polymerase with proofreading activity. This powerful single-base discrimination ability of exo(+) polymerases was further evaluated in primer extension using three types of 3' terminally modified allele-specific primers. As compared with the poor fidelity in primer extension of polymerases lacking 3' exonuclease activity, this study provides convincing evidence that the use of proofreading polymerases in combination with 3'-end modified allele-specific primers can be a powerful new strategy for the development of SNP assays.

Base Sequence↗
PubMed2003

Efficient mutagenesis method for producing the templates of single nucleotide polymorphisms.

DNA templates harboring specific single nucleotide polymorphism (SNP) sites are largely needed as positive controls in practical SNP analysis and in determination of the reliability of newly developed methods in high-throughput screening assays. Here we report a one-step method to produce SNP templates by amplifying a wild-type sequence with primers having single nucleotide mismatches at or near their 3' ends. A short amplicon harboring an EcoRI site was used to evaluate the feasibility of our strategy. Perfectly matched primers and primers with a single base mismatch occurring from the first base to the sixth base of the EcoRI site were used for primer extension. By using polymerase without a proofreading function, we kept mismatched nucleotides from occurring in extended primer products, as confirmed by EcoRI digestion and sequencing analysis. The strategy of using primers with a single mismatched base and exo- polymerase was shown to be an efficient one-step method for preparing SNP templates, either for application in the development of SNP screening assays or as positive controls in practical SNP assays.

Base Sequence↗
PubMed2003

De novo synthesis of PCR templates for the development of SARS diagnostic assay.

A novel coronavirus was identified as the cause for severe acute respiratory syndrome (SARS). The complete sequence of SARS genome has provided an opportunity for the development of molecular diagnostic assays. To restrain further outbreak of SARS, the World Health Organization has posted several pairs of polymerase chain reaction (PCR) primers for early diagnosis and urged more research to be done on PCR protocols. Here we report a strategy for the de novo synthesis of PCR templates complimentary to the SARS virus genome, which has the advantage of working on PCR templates without concern about viral infection and also has the advantage that it can be used by those who do not have access to the SARS virus. This highly efficient and safe strategy for obtaining SARS gene fragments is useful for the development of PCR assays, as well as for the preparation of reliable positive controls for PCR testing kits.

Base Sequence↗
PubMed2003

Single-base discrimination mediated by proofreading 3' phosphorothioate-modified primers.

It has been well known for decades that deoxyribonucleic acid (DNA) polymerases with proofreading function have a higher fidelity in primer extension as compared to those without 3' exonuclease activities. However, polymerases with proofreading function have not been used in single nucleotide polymorphism (SNP) assays. Here, we describe a new method for single-base discrimination by proofreading the 3' phosphorothioate-modified primers using a polymerase with proofreading function. Our data show that the combination of a polymerase with 3' exonuclease activity and the 3' phosphorothioate-modified primers work efficiently as a single-base mismatch-operated on/off switch. DNA polymerization only occurred from matched primers, whereas mismatched primers were not extended at the broad range of annealing temperature tested in our study. This novel single-base discrimination method has potential in SNP assays.

Base Sequence↗
PubMed2003

[Effect of 3' exonuclease activity of polymerase on extension of phosphorothioate-modified primers].

OBJECTIVE: To determine whether 3'phosphorothioate-modified-2 terminal mismatched primers can turn off DNA polymerization mediated by Exo(+) polymerase. METHODS: Two-directional primer extension was performed using polymerase with and without 3' exonuclease activity. The effects of unmodified primers and 3' phosphorothioate-modified primers on primer extension were evaluated. RESULTS: Exo(-) polymerase yielded products from matched and mismatched primers regardless of their modification. However, 3' phosphorothioate-modified primers with a single base mismatch at -2 position worked similarly to the terminal (-1) mismatched primers in triggering the novelly reported "off-switch" of Exo(+) polymerase. CONCLUSION: These data suggested that the "off-switch" can be of enormous application in the diagnosis of single gene diseases and in the association studies by single nucleotide polymorphism screening.

DNA Primers↗