Biomedical subjects
Publications and source records attributed to Min Sun.
OBJECTIVE: To obtain the hairy-roots of Dendrobium nobile. METHODS: The hairy-root were obtained by infecting different explants with Agrobacteriun rhizogenes A4 and culture conditions of hariy root were optimized. RESULT: The best conditions of hairy root culture were 1/2MS medium with sucrose (3%) as carbon material and lactalbumin hydrolyze (1g/L) as nitron material.
A novel europium(III) complex, tris(dibenzoylmethanato)(2-4'-triphenylamino)imidazo[4,5-f]1,10-phenanthroline)europium(III), Eu(DBM)3(TPIP), is synthesized. The light-emitting center, hole-transporting triphenylamine and electron-transporting phenanthroline fragments are integrated into one molecule. A single-layer device of ITO/Eu(DBM)3(TPIP) (60 nm)/Mg0.9Ag0.1/Ag exhibits Eu(III)-based pure red emission with a maximum brightness of 19 cd m(-2) at 13.5 V and 280 mA cm(-2), and an onset driving voltage of 8 V. A four-layer device of ITO/TPD (20 nm)/Eu(DBM)3(TPIP) (40 nm)/BCP (20 nm)/AlQ(40 nm)/Mg0.9Ag0.1/Ag gives a maximum Eu(III)-based pure red emitting luminance of 1305 cd m(-2) at 16 V and 255 mA cm(-2) with an onset driving voltage of 6 V; the maximum external quantum yield and luminous yield are estimated to be 0.85% and 1.44 lm W(-1), respectively, at 7.5 V and 0.25 mA cm(-2).
The Coronaviridae family is characterized by a nucleocapsid that is composed of the genome RNA molecule in combination with the nucleoprotein (N protein) within a virion. The most striking physiochemical feature of the N protein of SARS-CoV is that it is a typical basic protein with a high predicted pI and high hydrophilicity, which is consistent with its function of binding to the ribophosphate backbone of the RNA molecule. The predicted high extent of phosphorylation of the N protein on multiple candidate phosphorylation sites demonstrates that it would be related to important functions, such as RNA-binding and localization to the nucleolus of host cells. Subsequent study shows that there is an SR-rich region in the N protein and this region might be involved in the protein-protein interaction. The abundant antigenic sites predicted in the N protein, as well as experimental evidence with synthesized polypeptides, indicate that the N protein is one of the major antigens of the SARS-CoV. Compared with other viral structural proteins, the low variation rate of the N protein with regards to its size suggests its importance to the survival of the virus.
A method is developed to precisely determine Mg/Ca and Sr/Ca ratios in biocarbonates by inductively coupled plasma atomic emission spectrometry (ICP-AES). This method precision (RSD%) is 0.52% for Mg/Ca and 0.28% for Sr/Ca, respectively. The precision suggests that ICP-AES is satisfactory for supplying good quality Mg/Ca and Sr/Ca data of biocarbonates for paleo-reconstruction. This ICP-AES technique was applied to 51 continuous coral subsamples, and the results show annually periodical variations in coral Mg/Ca and Sr/Ca ratios, which are consistent with previous findings.
BACKGROUND & OBJECTIVE: Though the molecular etiology of nasopharyngeal carcinoma(NPC) is currently unknown, evidence from both loss of heterozygosity analysis and functional studies suggested that there are NPC-associated tumor suppressor genes(TSGs) residing in chromosome 3p21.3. Recently, two members of semaphorin family, SEMA3B and SEMA3F gene, located at 3p21.3, were characterized as TSGs. Studies showed that SEMA3B and SEMA3F are capable of suppressing the growth of tumor cells and inducing apoptosis. Loss of SEMA3B mRNA expression or aberrant SEMA3F cellular localization were found in lung cancers. In order to investigate the involvement of SEMA3B and SEMA3F in NPC, the authors examined both mutation and expression of these two genes in NPC. METHODS: The entire coding regions, the splice donor/acceptor sites, and partial regulatory regions of SEMA3B and SEMA3F gene were screened for mutations by PCR-sequencing in 21 primary NPC tumors and 2 NPC cell lines(CNE2 and SUNE1). The mRNA expression levels were determined by semi-quantitative RT-PCR analysis. RESULTS: No somatic mutation was found in either SEMA3B or SEMA3F gene. However, two missense polymorphisms including Thr415Ile and lle242Met were found in SEMA3B in NPC. For the Thr415Ile polymorphism, the Ile allele type which leads to SEMA3B function defects was predominant in NPC with the allele frequency of 64% (27/42). SEMA3B mRNA was expressed in all 6 non-neoplastic nasopharyngeal epithelia, but was absent or down-regulated in 76% (16/21) of primary NPC tumors. No significant difference of SEMA3B expression was observed between NPC and noncancerous controls. CONCLUSION: High frequency of SEMA3B expression alterations suggests that the inactivation of this gene was strongly associated with NPC. SEMA3B may be a tumor suppressor on 3p21.3 involved in NPC.
To study the changing regularity of leptin during puberty in girls and the relationship of leptin, estradiol and testosterone each other, serum levels of leptin, estradiol(E2) and testosterone(T) were determined in blood in 150 obese girls, 150 normal girls and 150 malnourished girls, aged from 7 to 17 years old. Their ages of menarche were surveyed. The results showed that serum levels of leptin increased with age, and had double peaks. The first peak of leptin was found during the early phase of puberty in all groups. The value of peak were 14.46 micrograms/ml, 8.85 micrograms/ml, 8.60 micrograms/ml in obese, normal and malnourished groups respectively. The second peak of leptin emerged at the end of puberty in the three groups. The level of E2 increased sharply at the eleven years old in three groups, then increased progressively with age. Serum level of E2 did not correlated with leptin. There was a peak level of T at 10 years old in obese groups, as well as normal and malnourished groups. The level of T emerged rise sharply at 12 years old after a decrease in all groups. Serum level of T did not correlated with leptin. It is suggested that leptin may be a more important decisive factor during pubertal development course in girls. The first peak of leptin may be the signal of onset of puberty. The second peak of leptin may be the signal of the end of puberty.
A method was developed for simultaneous determination of major (Ca), minor (Mg and Sr) and trace (Ba and U) elements in biocarbonates by inductively coupled plasma mass spectrometry (ICP-MS). The method precision (RSD%) is 0.73% for Ca, 0.77% for Mg, 0.59% for Sr, 2.02% for Ba, 1.13% for U, 0.67% for Mg/Ca, 0.27% for Sr/Ca, 2.06% for Ba/Ca and 1.23% for U/Ca. The ratio precision suggests that ICP-MS is satisfactory for obtaining multi-ratio data from biocarbonates. This technique was applied to 67 continuous coral samples.
Little is known about genomic alterations during development of the radial growth phase (RGP) of cutaneous malignant melanomas (CMMs). In this investigation polymerase chain reaction-based microsatellite assays were applied to analyze 13 RGP-CMMs with 18 microsatellite markers at six chromosomal regions: 1p, 3p, 4q, 6q, 9p, and 10q. Loss of heterozygosity (LOH) was found in eight cases (62%), at 9p22, 1p36, and 10q11, suggesting the presence of tumor-suppressor genes at these regions. LOH was encountered frequently at the interferon-alpha (31%) and D10S249 loci (15%). Low-level microsatellite instability (MSI) (11-16% of investigated loci unstable) was noted in three cases (23%). Two MSI banding patterns were seen: band shift and the presence of additional bands. To investigate the underlying mechanisms of the low-level MSI pattern, we analyzed the lesions for expression of mismatch repair (MMR) proteins with immunoperoxidase methods and mouse monoclonal antibodies. The average percentages of positively stained cells for human MutL homolog 1 (hMLH1), human MutS homolog 2 (hMSH2), and human MutS homolog 6 (hMSH6) in RGP-CMM (75.6 +/- 3.4%, 67.20 +/- 7.71%, and 76.6 +/- 2.1%, respectively) were reduced compared with benign nevi. No statistically significant differences in MMR protein expression were found between microsatellite-stable and low-level MSI lesions (P = 0.173, P = 0.458, and P = 0.385 for hMLH1, hMSH2, and hMSH6, respectively). There was a direct correlation between values for percentages of positively stained cells for hMSH2 and hMSH6 (r = +0.9, P = 0.03), suggesting that common mechanisms regulate their expression. In conclusion, LOH, MSI, and reduced MMR protein expression appear to be present in at least some RGP-CMMs and may play a role in their pathogenesis. Further studies are necessary to support these finding and to determine their diagnostic and prognostic significance.