Biomedical subjects

Ping Yuan

Publications and source records attributed to Ping Yuan.

23 records · Page 2Linked to original sources

PubMed2004

[N II ion spectra related to lightning discharges].

Appling the atomic structure theory to the research field of physical processes of lightning discharges, parameters such as wavelengths, oscillator strengths, transition probabilities and excitation energy of upper levels have been calculated for the transitions of N II ions related to lightning discharges. Large-scale multi-configuration Dirac-Fock wavefunctions were applied to include the most important effects of relativity, correlation, and rearrangement of the electron density within the same (computational) model. More detailed identification than ever for lightning spectra has been done, and reference data have been provided for further theoretic and experimental works on the physical mechanism of lightning discharges.

English Abstract↗

PubMed2003

A HEX-1 crystal lattice required for Woronin body function in Neurospora crassa.

The Woronin body is a dense-core vesicle specific to filamentous ascomycetes (Euascomycetes), where it functions to seal the septal pore in response to cellular damage. The HEX-1 protein self-assembles to form this solid core of the vesicle. Here, we solve the crystal structure of HEX-1 at 1.8 A, which provides the structural basis of its self-assembly. The structure reveals the existence of three intermolecular interfaces that promote the formation of a three-dimensional protein lattice. Consistent with these data, self-assembly is disrupted by mutations in intermolecular contact residues and expression of an assembly-defective HEX-1 mutant results in the production of aberrant Woronin bodies, which possess a soluble noncrystalline core. This mutant also fails to complement a hex-1 deletion in Neurospora crassa, demonstrating that the HEX-1 protein lattice is required for Woronin body function. Although both the sequence and the tertiary structure of HEX-1 are similar to those of eukaryotic initiation factor 5A (eIF-5A), the amino acids required for HEX-1 self-assembly and peroxisomal targeting are absent in eIF-5A. Thus, we propose that a new function has evolved following duplication of an ancestral eIF-5A gene and that this may define an important step in fungal evolution.

Amino Acid Sequence↗

PubMed2003

[Meta-analysis of risk factor on hypertension in China].

OBJECTIVE: To evaluate the risk factor of hypertension in China. METHODS: The results of 24 case-control studies from 1989 to 2001 were analyzed by Meta-analysis method in this study. Random effect model (D-L method) and fix effect model (M-H method) were applied for data processing. RESULTS: The pooled OR values (95% CI) of drinking, smoking, over-intake of salt, family history of hypertension, quickness to temper and overweight were 1.194 (1.184-1.203), 1.100 (1.096-1.104), 1.165 (1.157-1.173), 2.662 (2.550-2.779), 2.524 (1.902-3.348), 1.616 (1.600-1.633), respectively. CONCLUSION: Drinking alcohol, smoking, over-intake of salt, family history of hypertension, quickness to temper and overweight were the important risk factors of hypertension in China.

Alcohol Drinking↗

PubMed2003

[Expression of cyclooxygenase-2 mRNA and identification of its spliceriant in human myometrium obtained from women in labor].

OBJECTIVE: To investigate the expression of cyclooxygenase-2 (COX-2) in human lower segments of myometrium obtained from women in labor and those not in labor and identify the splice variant of COX-2. METHODS: Reverse transcriptase-polymerase chain reaction (RT-PCR) was used for investigating the expression of COX-2. According to the sequence of rat COX-2 splice variant, the primers were designed and synthesized, then the splice variant of COX-2 in human myometrium from woman in labor was identified, cloned into vector and sequenced. RESULTS: The results showed that (1) The Expression of COX-2 mRNA was lower in human myometrium obtained from women who were not in labor than those in labor. (2) A new band of COX-2 was obtained in myometrium from a woman in labor. The fragment includes an unspliced intron, which locates between exons 7 and 8. CONCLUSION: COX-2 gene is not only expressed highly in human myometrium from women in labor, but also produced splicing variant by alternative splicing.

Adult↗

PubMed2002

[Loss of heterozygosity on chromosome loci 2, 3, 5, 11, 17, and 18 in aberrant crypt foci of human colon].

OBJECTIVE: To study the genetic basis of aberrant crypt foci (ACF), which serve as a very early morphological alteration during the development of carcinogenesis by analyzing the loss of heterozygosity (LOH). METHODS: DNA from 35 colorectal carcinomas (CRC) and 34 matched ACF were isolated by microdissection. LOH of microsatellite loci at 18q12, 18q21, 5q12, 5q21, 3p21, 2p16, 17q21, 17q11 and 11p13 was detected by means of ABI-SEQUENCER and GeneScan software was applied for analysis. RESULTS: The rate of LOH in ACF (41.18%) was less than that in carcinoma (68.57%) (P < 0.05). The profile of LOH rates at loci 18q12, 5q12, 3p21, 17q21, 17q11, 11p13 and 2p16 in ACF was similar to that in carcinoma. The LOH frequencies on 18q12, 18q21, 5q12, 5q21, and 3p21 were higher than that on 17q11 and 11p13. However the rate at 18q21 and 5q21 in ACF was much lower than that in the carcinoma (P < 0.05). The co-existing carcinomas displayed more polypoid growth pattern and located more at the sigmoid colon and rectum. LOH in carcinomas did not correlate with the location, size, type of the carcinoma and Duke's stage. CONCLUSIONS: ACF are putative preneoplastic lesions that might represent the earliest morphological lesion with the alteration at molecular genetic level. Our study provides further genetic evidence in the pathogenesis of colorectal carcinomas.

Chromosomes↗