Biomedical subjects

Mei Han

Publications and source records attributed to Mei Han.

60 records · Page 4Linked to original sources

PubMed2003

[Determination of trace Rh in organic residue by flame atomic absorption spectrophotometry].

The catalytic organic residue contained Rh was digested with HNO3 at 130 degrees C for 12 h. Trace noble metal Rh in catalytic organic residue was determined by flame atomic absorption spectrophotometry. Rh was atomized by air-acetylene flame at lamp Current of 7 mA. The methods of sample pretreatment for Rh in residue were compared in this paper. The recovery rates of this method were 95.3%-105.5% and the relative standard derivation was 0.9%. The method was applied to the analysis of some practical samples and the results obtained were satisfactory.

Acetylene↗

PubMed2003

[Photolysis kinetics of propisochlor in water].

Propisochlor in water was irradiated at room temperature by a 400 W high pressure mercury lamp and sunlight, respectively. Influence of light and initiative concentration of propisochlor on the photolysis were studied. The results showed that under the irradiation of sunlight the photolysis fitted first order kinetics with only 5.5% degradation after one hour's irradiation in the quartz tube, that was a slow rate; while under the irradiation of high pressure mercury lamp the photolysis can be described by a double-chamber model, in which the degradation rate can reach 80.9% after 1 h. The higher the initiative concentration of propisochlor was, the slower the photolysis rate became, and the photolysis of propisochlor was influenced by the increasing photo-products. The six main photodegradation products were identified using GC-MS method. The aromatic ring was proved to be intact during the process. And the photolysis mechanism was then assumed on the basis of the photo-products detected.

Acetamides↗

PubMed2002

Influence of the period-dependent circadian clock on diurnal, circadian, and aperiodic gene expression in Drosophila melanogaster.

We measured daily gene expression in heads of control and period mutant Drosophila by using oligonucleotide microarrays. In control flies, 72 genes showed diurnal rhythms in light-dark cycles; 22 of these also oscillated in free-running conditions. The period gene significantly influenced the expression levels of over 600 nonoscillating transcripts. Expression levels of several hundred genes also differed significantly between control flies kept in light-dark versus constant darkness but differed minimally between per(01) flies kept in the same two conditions. Thus, the period-dependent circadian clock regulates only a limited set of rhythmically expressed transcripts. Unexpectedly, period regulates basal and light-regulated gene expression to a very broad extent.

Animals↗

PubMed2002

Comparison of gene expression patterns and migration capability at quiescent and proliferating vascular smooth muscle cells stimulated by cytokines.

The changes of the gene expression patterns and the migration capability of vascular smooth muscle cells (VSMC) at the quiescent and proliferating states were investigated after VSMC was stimulated by cytokines. VSMC migration was measured using a model of wounding injury of confluent cultured cells and a Boyden chamber assay. The migration distance of the quiescent VSMC induced by cytokines bFGF, IL-1beta and TNF-alpha was 5.8, 4.7, and 4.2 times as long as that of the control group, respectively. However, the migration distance of the proliferating VSMC was only one-fourth of the quiescent cells under the same effects. The results of Boyden chamber assay indicated that VSMC was capable of degrading collagen and traversed the pores of membrane barriers in response to bFGF as a chemoattractant, and VSMC number across the membrane was markedly increased as concentration gradient of bFGF ascended. Northern blot and nuclear run-off assay showed that bFGF not only stimulated the expression of migration-related matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) but also enhanced the transcription of proliferation-related osteopontin (OPN) and c-jun genes in the quiescent VSMC. bFGF could moderately increase the expression of OPN and c-jun, but had no significant effect on the expression of MMP-2 and TIMP-2 in the proliferating cells under the same conditions. These findings suggest that VSMC migration capability and the expression activity of migration- and proliferation-related genes were significantly distinct for the quiescent and proliferating VSMC. The cellular migration capability and the expression activity of migration-related genes in the quiescent VSMC were much higher than those in the proliferating cells in response to cytokines.

Animals↗

PubMed2002

[Application of confocal scanning laser Doppler retinal flowmetry in the measurement of fundus blood flow parameters after retinal detachment surgery].

OBJECTIVE: To discuss the influence of retinal detachment (RD) surgery on the blood flow of retina and optic nerve head. METHODS: Heidelberg Retina Flowmeter (HRF) was used to measure the blood flow of retina and optic nerve head in 62 eyes of 62 patients with postoperative rhegmatogenous RD surgery, including 34 eyes having undertaken vitreoretinal (VR) surgery and 28 eyes, scleral buckling (SB) surgery. Operative methods included scleral encircling procedure, cryotherapy, lensectomy, vitrectomy, perfluorodeclin liquid application, endolaser and C(2)F(6) gas or silicone oil tamponade. RESULTS: The blood flow volume (VOL), blood flow velocity (FLW) and the erythrocyte flow velocity (VEL) of fundus in the postoperative RD eyes were reduced in the comparison with those of the fellow control eyes. The VEL of temporal and nasal papillary disk rim had significant differences (P < 0.05). The VOL, FLW and VEL of the papillary vessel, VOL and FLW of temporal and nasal papillary disk rim, VOL of temporal and nasal juxtapapillary retina in the operative eyes were lower than those of the fellow eyes (P < 0.01). In the comparison between the eyes having undertaken VR surgery and the eyes undertaken SB surgery, the VOL, FLW and VEL of VR surgery were reduced more than those of SB surgery. The VEL of temporal and nasal papillary disk rim and nasal juxtapapillary retina and FLW of temporal juxtapapillary retina had significant differences (P < 0.05). VOL, FLW and VEL of silicone oil tamponade eyes were reduced more than those in the operative eyes without silicone oil tamponade. VOL of nasal papillary disk rim and juxtapapillary retina had significant differences (P < 0.05). VOL and VEL of temporal papillary disk rim, VOL of temporal juxtapapillary retina had very significant differences (P < 0.01). CONCLUSIONS: VR surgery and SB surgery of RD influence papillary and retinal VOL, FLW, VEL. The influence of VR surgery on the fundus blood flow is more significant than that of SB surgery. The silicone oil tamponade also influences the VOL and VEL of the fundus.

Adolescent↗

PubMed2002

[A review of the research progress on LIM protein family].

LIM Proteins contain one or more LIM domains. Proteins of this family capable of interacting with many types of proteins have been identified including structural protein, kinase, and several classes of transcription factors. These interactions have been discovered to display important roles in a variety of fundamental processes including transcriptional regulation, development of cell types and organization of the cytoskeleton. This article reviews recent advances in the characterization of members of the LIM protein family, their biology roles, LIM domain binding protein and the function in heart development.

Animals↗