Biomedical subjects
Publications and source records attributed to S Peng.
The determination of As, Hg and Mo in the composite Chinese traditional medicines such as niuhuang jiedu tablets etc. Indicates the existence of As, Hg and Mo in these medicines. The relation between these elements and the efficacy of the medicines was studied, showing that these elements play an important role in the efficacy of the drugs.
The gene responsible for cystic fibrosis encodes a membrane protein--the 1480-residue cystic fibrosis transmembrane conductance regulator (CFTR)--in which membrane-based CF-phenotypic mutants alter pore structure and/or impair ion transport. We report the preparation in milligram quantities and conformational characterization of a polypeptide comprised of CFTR transmembrane (TM) segments 3-4, a putative 'helical hairpin' portion of the CFTR TM1-6 domain. The TM segment 3-4 of CFTR was expressed in E. coli as a fusion protein linked to the C-terminus of His-tagged thioredoxin. Nickel chelate affinity chromatography, followed by release from the carrier by digestion with thrombin protease, gave free CFTR(TM3-4). Monitoring of the folding properties and conformational state(s) of the TM3-4 polypeptide using circular dichroism spectroscopy indicated a partial alpha-helical conformation in aqueous buffer, with up to 30% increase in alpha-helical content observed in membrane-mimetic environments.
To evaluate an antigen delivery system in which exogenous antigen can target the major histocompatibility complex (MHC) class I pathway, a single human papillomavirus (HPV) 16 E7 cytotoxic T lymphocyte (CTL) epitope and a single HIV gp160 CTL epitope were separately fused to the C-terminus of bovine papillomavirus 1 (BPV1) L1 sequence to form hybrid BPV1L1 VLPs. Mice immunized with these hybrid VLPs mounted strong CTL responses against the relevant target cells in the absence of any adjuvants. In addition, the CTL responses induced by immunization with BPV1L1/HPV16E7CTL VLPs protected mice against challenge with E7-transformed tumor cells. Furthermore, a high titer-specific antibody response against BPV1L1 VLPs was also induced, and this antiserum could inhibit papillomavirus-induced agglutination of mouse erythrocytes, suggesting that the antibody may recognize conformational determinates relevant to virus neutralization. These data demonstrate that hybrid BPV1L1 VLPs can be used as carriers to target antigenic epitopes to both the MHC class I and class II pathways, providing a promising strategy for the design of vaccines to prevent virus infection, with the potential to elicit therapeutic virus-specific CTL responses.
AF10, a human B cell line, is a mycoplasma-free variant cloned from the human IgE myeloma cell line U266. Total RNA isolated from the AF10 cells was used as template for RT-PCR, and a specific product of about 411bp corresponding to the coding region of hIL-17 lack of a leading sequence obtained. The sequence of the RT-PCR product is the same to that reported in the literature. The expressed rhIL-17 in E. coli can induce 10- to 15-fold increase of IL-6 secretion by mouse fibroblast 3T3 cells. It is for the first time until now that hIL-17 messager has been detected in B cell. There may exist some potential relationship between hIL-17 and myeloma cells.
Human interleukin-17 (hIL-17) gene without the signal sequence was isolated from activated peripheral blood lymphocytes by RT-PCR, then highly expressed in the yeast Pichia pastoris in the form of the glycosylated monomer. The monomer of rhIL-17 stimulated mouse fibroblast 3T3 cells to secrete IL-6 and was specifically bound to its receptors on 3T3 cells.
The action potentials of ventricular myocardial cells were recorded with glass microelectrodes inside the cells from neonatal Wistar rats treated with selenomethionine and sodium selenite in concentrations of 1.0, 2.0, and 4.0 mg/L selenium. Both of selenomethionine and sodium selenite decreased the action potential parameters, such as action potential amplitude(APA), overshoot(OS), threshold potential(TP), maximum diastolic potential (MDP) and maximum rate of depolarization (Vmax). Selenomethionine decreased the action potential duration at 10%, 50% and 90% repolarization (APD10, APD50 and APD90), while sodium selenite prolonged APD10, APD50 and APD90 at dose of 4.0 mg/L selenium and decreased APD50 and APD90 at dose of 1.0 and 2.0 mg/L selenium. The results indicated that both sodium selenite and selenomethionine inhibit the transmembrane movement of Ca2- and sodium selenite also inhibits transmembrane movement of K+.
A test was made on the effect of rotundine on the secretion of gastric acid and pepsin activity in rats. Compared with the control group, rotundine(> or = 17.1 mg/kg) inhibited gastric acid and decreased secretion of gastric juice(P < 0.01), but had no influence on pepsin activity. There was a negative relationship between total acidity and pH of gastric juice (r = -0.9818).
OBJECTIVE: To study the effect of detrusor instability secondary to benign prostatic hypertrophy (BPH) on the density of cholinesterase-containing nerve in detrusor samples. METHOD: Our present study included 3 groups confirmed by urodynamic evaluation. They were control group (8 cases), obstructive detrusor stability group (7), and obstructive instability group (12). The specimens were obtained from the dome of bladder. The AchE-containing nerves were demonstrated by the method of Karnovsky-Roots staining and AchE silver staining. The density of AchE containing detrusor nerves in specimens was examined with sterologic techniques. RESULT: The density of AchE-containing nerves in the obstructive detrusor instability group and the stability group was significantly decreased as compared with the control group (P < 0.01). The density of AchE positive nerves were also significantly decreased in the obstructive instability group as compared with the obstructive stability group (P < 0.05). CONCLUSION: Detrusor instability secondary to BPH obstruction is related to the decrease of cholinergic innervation density in the detrusor muscles.
OBJECTIVE: To investigate, at transcriptional and translational level in situ, the abnormal gene expression of the Ki-67 protein in pancreatic carcinoma specimens. METHOD: 40 pancreatic cancer specimens, 5 normal pancreatic and 4 chronic pancreatitis tissues were studied. A 435 bp cDNA fragment located in codon 2, exon 13 of the Ki-67 antigen gene was amplified by the polymerase chain reaction (PCR). The DIG-labeled cRNA probes were transcribed using a commercially available DIG RNA labeling kit. Localization of the Ki-67 protein and the specific mRNA were studied by combining immunohistochemistry (ICH) with (DIG)-labeled in situ hybridization (ISH). RESULT: The Ki-67 protein mRNA in formalin-fixed and paraffin-embedded pancreatic tissue sections was successfully localized. Analyzing the Ki-67 mRNA transcription in 17 pancreatic cancer specimens with Ki-67 ICH labeling index > 20%, we found that stronger mRNA signals were also observed in poorly differentiated specimens with Ki-67 index > 50% than in those well differentiated with ICH labeling index 20% - 50%. A high expression of both mRNA and protein was observed in poorly differentiated pancreatic adenocarcinomas. CONCLUSION: Abnormal overexpression of the gene encoding Ki-67 protein was detected not only at the protein level, but also at the mRNA level in pancreatic tumors. The abnormal overexpression of the Ki-67 protein might be correlated with the central part, exon 13, of the gene.
OBJECTIVE: To understand the natural history and the risk factors of primary angleclosure glaucoma and obtain experiences that might help screening for the disease. METHODS: Four hundred and eighty-five suspects were screened from 6 548 population aged over 40 years. The suspects were then followed up within six years. The following examinations were performed: visual acuity, axial anterior chamber depth, peripheral anterior chamber depth, intraocular pressure and cup/disc ratio of optic nerve papilla. The suspects with high risk were further examined. RESULTS: During the follow-up period, twenty patients (4.1%) in the suspects developed angle-closure glaucoma, 14 cases had natural attack (Acute onset developed in 6 cases and 8 cases were in chronic stage) and 6 cases were found at early stage. The anterior chamber depth shallowed progressively in 28% of suspects. CONCLUSION: Anterior chamber depth is an important index for screening of primary angle-closure glaucoma, and the regular follow-up is of significance for the suspects.
Hydrocortisone was coupled with urotoxin tripeptide UTP-A, UTP-B and UTP-C respectively yielding 4 linkers. Their bioactivities such as prolongation of heterotopic transplanted cardiac tissue survival, inhibitory effects on phagocytosis of mouse peritoneal macrophages and the influence on Con A induced proliferation of spleen lymphocytes of mouse were observed. Compared with UTP-A, UTP-B, UTP-C or hydrocortisone the linkers were more potent immunosuppressants. The results suggest that the linker of steroid-peptide may simulate the permissive action.
In an attempt to search for novel cardiovascular drugs which might act on calcium or potassium channels, on the basis of the previous study of our group, 15 1-(4-alkyloxy)benzyl-1,2,3,4-tetrahydroisoquinolines derivatives were designed and synthesized among which 10 were not reported previously in the literature. Preliminary pharmacological studies showed that most of these compounds exhibited relaxation of rat thoria aorta in vitro. Compound III9 exhibited potent inhibiting action on low KCl(20 mmol.L-1)-induced contraction of rat aorta, and significant protective effect on experimental arrhythmia in rats.
For searching more effective antiarrhythmic agents, on the basis of integration of the structural feature of certain potassium channel blockers available, various acylamino groups were introduced to the position 4 of the benzyl ring of this series of compounds. Thus, eight 1-(4-acylamino)benzyl-1,2,3,4-tetrahydroisoquinolines were designed and synthesized, which had not been reported in the literatures. Compounds V1, V2 and V6 at concentration 10(-6) mol.L-1 depressed rat aortia contraction induced by high KCl (80 mmol.L-1). The effect was similar to that of tetrandrine. Compound V6 showed potent antiarrhythmic activity at the dosage of 1 mg.kg-1.
Determination of the contents of elements in Bean and Bean product using Z-8000 atomic absorption spectrometry is described. This results obtained indicate that high amounts of Mn, Fe and Mg are embodied in Bean and Bean-products. The Beans are good food for longevity and intelligence development.
Surface-covered nanometer-sized CuO/Al2O3, CuO-ZnO/Al2O3, and CuO/ZnO catalysts were prepared by phase transfer with carboxylate. The surface-covered structure was studied using XPS, XRD, TEM, and high-resolution electron microscope. The results indicated that amorphous CuO and ZnO were dispersed on the surface of nanometer-sized Al2O3 particles in catalysts CuO-ZnO/Al2O3 and CuO/Al2O3, respectively. The thickness of its surface layer is about several angstroms. No spinel structure was found in the catalyst. The particle size of the surface-covered CuO/Al2O3 catalyst was about 2-3 nm. Al2O3 in the catalyst was amorphous. Surface-covered material CuO in the catalyst with low CuO content was also armophous. A large amount of copper carboxylate resulted in crystalline CuO and Cu2O. The protective ability of carboxylate to sol particles differs from the metal element of carboxylate. Copyright 1997 Academic Press. Copyright 1997Academic Press
The role of lamotrigine (LTG) in childhood epilepsy is emerging. We evaluated the efficacy and adverse effects of LTG in an open, prospective study of 56 children with generalized epilepsies. Six (11%) children became seizure-free, and 24 (43%) had greater than 50% reduction in seizure frequency. LTG was effective against a broad range of generalized seizure types. Three of 15 patients with Lennox-Gastaut syndrome achieved complete seizure control and eight demonstrated 50 to 99% improvement in seizure control. Increase in seizures (7) and rash (5) were the most common side effects. After valproate was discontinued, LTG therapy was resumed, with no recurrence of rash in any patient. This study suggests that LTG may be a useful drug in the treatment of generalized epilepsies in children.
Internal deletion K128-Q175 of the human interleukin-6 (hIL-6) has been generated at the cDNA level. With pBV220 as expressing vector, the recombinant pBV*-DIL-6 encoding the deletion mutant (12 kD) of hIL-6 has been constructed. The resulted recombinant plasmids were then used to transform E. coli strain HB101, and the expression in the PLPR promoter system, which is temperature-regulatable, was achieved. After purification and renaturation, the biological activity of the expressed product, designated as DM120, was measured by MTT method in an IL-6-dependent cell line 7TD1. The results show that the amino acid residues of IL-6 128 to 175 are crucial for IL-6 activity. Receptor binding assay in vitro indicates that the entire region is not involved in forming the receptor binding surface.
We have characterized the gene flowering promoting factor1 (FPF1), which is expressed in apical meristems immediately after the photoperiodic induction of flowering in the long-day plants mustard and Arabidopsis. In early transition stages, expression is only detectable in the peripheral zone of apical meristems; however, later on, it can also be found in floral meristems and in axillary meristems that form secondary inflorescences. The FPF1 gene encodes a 12.6-kD protein that has no homology to any previously identified protein of known function. Constitutive expression of the gene in Arabidopsis under control of the cauliflower mosaic virus 35S promoter resulted in a dominant heritable trait of early flowering under both short- and long-day conditions. Treatments with gibberellin (GA) and paclobutrazol, a GA biosynthesis inhibitor, as well as crosses with GA-deficient mutants indicate that FPF1 is involved in a GA-dependent signaling pathway and modulates a GA response in apical meristems during the transition to flowering.