Biomedical subjects

Peng Gao

Publications and source records attributed to Peng Gao.

44 records · Page 3Linked to original sources

PubMed2004

[Clinical analysis of lymphangioleiomyomatosis].

OBJECTIVE: To improve the diagnosis and treatment of lymphangioleiomyomatosis (LAM). METHODS: The clinical data of four cases of lymphangioleiomyomatosis diagnosed in our hospital were analyzed and corresponding literature was reviewed. RESULTS: Lymphangioleiomyomatosis, a rare disorder of unknown cause that occured almost exclusively in women of child bearing ages, was characterized microscopically by atypical smooth muscle proliferation. It could occur as a sporadic diseases or as a part of tuberous sclerosis complex (TSC). LAM was associated with progressive dyspnea, recurrent spontaneous pneumothoraces, chylous effusions, and hamartomas. CONCLUSION: Clinicians should be familiar with the characteristics of LAM so that diagnosis and treatment can be made earlier to improve the prognosis.

Adolescent↗

PubMed2003

Cloning the full-length cDNA of a gene responsible for vascular smooth muscle cell proliferation in atherogenesis and study of function.

OBJECTIVE: To clone the full-length cDNA of a gene responsible for vascular smooth muscle cell (v-SMC) proliferation in atherogenesis, and study its function. METHODS: Oxidized low density lipoprotein (ox-LDL) at optimal concentration was used as the stimulant to induce v-SMC proliferation in culture medium. A cDNA subtractive library of v-SMC proliferation specific to ox-LDL stimulation was established using subtractive hybridization technique. Methods, including blotting, Northern hybridization and gene sequencing, were used to clone new gene fragments. By using full-length cDNA screening and protein expression techniques, one full-length cDNA was cloned and its function was studied. RESULTS: One full-length cDNA was cloned. The new gene (Genbank AF 174647) expressed a 44 kDa protein, which might be associated with the activity of ox-LDL. CONCLUSION: The new gene cloned may be associated with SMC proliferation in atherogenesis.

Amino Acid Sequence↗

PubMed2003

[Enhancement of gastrointestinal absorption of chitosan-coated insulin-loaded poly (lactic-co-glycolic acid) nanoparticles].

AIM: To study chitosan-coated poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) on enhancing gastrointestinal absorption of insulin. METHODS: Insulin-loaded PLGA multiple emulsions were prepared by a double-emulsion method. Using chitosan as a stabilizer, chitosan-coated PLGA-NPs was prepared. The changes of the morphology, size distribution and Zeta potential of the NPs were examined. The encapsulation efficiency was determined by HPLC. The release behaviors in vitro were assessed, and the hypoglycemic effects were evaluated by monitoring the glucose levels in diabetic rats. RESULTS: Chitosan-coated PLGA-NPs showed a narrow size of distribution and regular surface with layer structure and their Zeta potential can be changed by chitosan. Chitosan-coating increased the encapsulation efficiency of insulin, reduced the initial burst and improved the release behavior of the NPs. About 14-16 h after intragastric administration of chitosan-coated INS-PLGA-NPs, the plasma glucose level decreased significantly compared with intragastric administration of same dose of non-coated NPs (P < or = 0.05), and the relative pharmacological availability was increased up to (15.4 +/- 1.2)%. CONCLUSION: Chitosan-coated PLGA-NPs could enhance gastrointestinal absorption of insulin.

Animals↗

PubMed2003

[Preparation of sustained-release nitrendipine microspheres with a solid dispersed structure in liquid system].

AIM: To prepare the sustained-release nitrendipine microspheres with a solid dispersed structure in liquid system. METHODS: The sustained-release nitrendipine microspheres with a solid dispersed structure was prepared in liquid system by combining spherical crystallization technique and solvent deposition method in one step. The resultant microspheres were evaluated for the recovery, micromeritc properties, incorporation efficiency. The factors of effect on the formation and the release rate of microspheres were also investigated. RESULTS: The recovery of microspheres (280-900 microns) was more than 70% and the bulk density was around 0.7 kg.L-1. The incorporation efficiency always exceeded 95%. The formation of microspheres was mainly affected by the amount of bridging liquid and the emulsifying agents in poor solvent. The release rate of nitrendipine from the microspheres could be controlled as desired by adjusting the ratio of talc to Eudragit RS PO in the formulation. CONCLUSION: The presented method was suitable for preparing sustained-release microspheres of a water insoluble drug.

Delayed-Action Preparations↗

PubMed2003

[Reversal of multidrug resistance property of carcinoma cells by down-regulating transcription of mdr-1].

OBJECTIVE: To reverse the multidrug resistance (MDR) property of carcinoma cells by blocking transcription of activating sites of mdr-1. METHODS: Breast carcinoma cells were transinfected with several antisense oligonucleotide (ASODN) complementary to mdr-1 by lipofectin. RT-PCR was used to detect the production of mdr-1mRNA. The expression of P-glycoprotein (gp) was then detected by immunohistochemistry and the function of P-gp was detected by rhodamine123 retention. RESULTS: Forty-eight hours after transfection, mdr-1 index of cells treated by ASODN complementary to MA zone (major initiation start zone), MI (minor initiation start zone), C zone (CAAT box), G zone (GC box) of mdr-1 gene was 1.4, 1.9, 1.6 and 2.1 respectively. The rate of P-gp protein expression in treated cells was 14%, 43%, 26% and 39% respectively. The intracellular Rh123 retention in treated cells was 125%, 83%, 102% and 77% respectively. There was significant difference between cells treated by ASODN complementary to MA zone and C zone and drug-resistant cells. CONCLUSIONS: The ASODN complementary to MA zone and C zone of mdr-1 gene can reverse MDR of drug-resistant cells to various extent, amongst which the former is more effective. Down-regulating transcription of mdr-1 by blocking transcription activating sites can reduce the expression of mdr-1mRNA and P-gp, and thus reversing MDR of carcinoma cells. The ASODN complementary to MI zone, G zone of mdr-1 however do not significantly reverse the MDR property.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2002

Aqua(4,4'-oxydibenzoato-kappa O)cadmium(II).

The Cd atom in the polymeric title compound, [Cd(C(14)H(8)O(5))(H(2)O)](n), is linked to four carboxyl O atoms and a water molecule in a five-coordinate coordination polyhedron that is midway between a square pyramid and a trigonal bipyramid. The Cd atom and the water molecules both lie on the same twofold axis and the central O atom of the 4,4'-oxydibenzoate moiety lies on another twofold axis. Covalent Cd-O bonds lead to the formation of a layer architecture perpendicular to the twofold axis, the layers being held together by hydrogen bonds in the third direction.

Journal Article↗

PubMed2002

[Enhancing hGH expression level in insect cells by shortening the 5'-UTR of hGH cDNA].

The regulation of foreign gene expression in Insect-Baculovirus Expression System is very complex. In this report, the effect of 5'-UTR in the expression of hGH gene in cultured Sf9 cells was examined. A 18 bp length in the end of 5'-UTR of hGH (human Growth Hormone, hGH) cDNA including a stem-loop structure was deleted by PCR. The truncated hGH cDNA, delta 1hGH was cloned in pFastBac1, named pFast-Bac-delta 1hGH. After transforming into E. coli. DH10Bac, which have a shuttle vetor-Bacmid, the delta 1hGH was integrated into Bacmid by site-specific transposition, and an expression vector, rBacmid-delta 1hGH DNA was acquired. By transfecting the cultured Sf9 cells with the recombinant expression vector DNA, pure recombinant virus, rAcV-Bac-delta 1hGH was obtained, and hGH gene was expressed. Immuno-blot and Chemiluminescent assay revealed that the expressed hGH had normal immunological activity, the amount of hGH expression level in Sf9 cell supernatant infected with rAcV-Bac-delta 1hGH containing the truncated 5'UTR was four to five times higher than that infected with rAcV-Bac-hGH.

5' Untranslated Regions↗

PubMed2002

[Role of placental apoptosis in fetal growth restriction].

OBJECTIVE: To determine the relationship of placental cellular apoptosis and pathophysiology of fetal growth restriction (FGR). METHODS: Placental samples were obtained from 18 pregnancies complicated by FGR and 14 normal pregnancies. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) and transmission electron microscopy were used to confirm the occurrence of apoptosis. RESULTS: In FGR group the placental apoptosis rate was (n = 18) 12.1 per thousand, the average placental weight was (236 +/- 24) g, the average birth weight was (2,071 +/- 428) g; In normal group (n = 14), the placental apoptosis rate was 7.3 per thousand, the average placental weight was (354 +/- 63) g, the average birth weight was (3,411 +/- 588) g (P < 0.05). The incidence of apoptosis was significantly higher in placental samples from pregnancies with FGR compared with normal placental samples (P < 0.05). Under transmission election microscopy, apoptosis was obviously compact and the chromatins were formed as mass. CONCLUSION: These results suggest that apoptosis may play a role in the pathophysiologic mechanisms of FGR.

Adult↗