Search PubMed⌕ Search

Biomedical subjects

J Peng

Publications and source records attributed to J Peng.

At least 91 records · Page 5Linked to original sources
PubMed2000

[Melanoma antigen-3 expression in human hepatocellular carcinoma].

OBJECTIVE: To investigate the expression of melanoma antigen-3 (MAGE-3) mRNA in human hepatocellular carcinoma (HCC) and probe into the theoretical feasibility that MAGE-3 antigens can be developed as a new peptide vaccine for immunotherapy in HCC patients. METHODS: The expression of MAGE-3 mRNA in HCC tissues and the adjacent non-HCC liver tissues was studied using RT-PCR in 45 HCC patients. The results were compared with those of 16 cirrhotic patients and 12 patients whose liver tissues were pathologically normal. MAGE-3 mRNA positive PCR products were DNA sequenced in 3 HCC patients. The sequenced fragments of MAGE-3 cDNA were used as template by which a [alpha(32)P] labeled probe was synthesized and employed for Southern blot analysis. HLA class I-A and -B typing of 43 HCC patients were assayed by ELISA. RESULTS: Of the 45 HCC samples, 35 (78%) expressed MAGE-3 mRNA and six HCC adjacent tissues were also positive in MAGE-3 expression. Pathological examination showed cellular heteromorphism in these adjacent tissues. The non-HCC liver tissues from cirrhosis and normal liver samples were not MAGE-3 mRNA detectable. The DNA sequence confirmed that the target gene fragment in all of the 3 samples of PCR products was MAGE-3 cDNA. Southern blotting result confirmed that of RT-PCR assay. In HCC patients, the predominant types of HLA were A(2) (53.5%), A(11) (25.6%), A(24) (20.9%), A(33) (20.9%), B(13) (28.3%), and B(35) (23.2%). MAGE-3 mRNA expression in HCC showed no correlation with the level of serum AFP and the size of the tumor. CONCLUSIONS: MAGE-3 mRNA is expressed at a high percentage of HCC samples. This tumor rejection antigen may be used as peptide vaccine for immunotherapy of HCC patients. The phenomena that some non-HCC adjacent tissues with heteromorphism can express MAGE-3 like their paired HCC tissues indicate that the expression of MAGE-3 may be an indicator in the early stage of carcinogenesis of liver tissues.

Aged↗
PubMed2000

[Epidemiological feature on diabetes mellitus among permanent inhabitant in the Special Economic Zone of Shenzhen].

OBJECTIVE: To investigate prevalence and relevant factors of diabetes mellitus among permanent inhabitant in Shenzhen. METHODS: The prevalence of 8 200 inhabitants aged over 20 in Shenzhen was studied. Blood glucose was determined by glucose - oxidase method. RESULTS: According to the WHO diagnostic standard, the prevalence rates of DM and IGT were 4.23% and 11.94% respectively. The prevalence increased apparently with age. The history of clan and overweight were related to the prevalence rates of DM and IGT. The people of DM and IGT were mostly accompanied with high levels of triglyceride, total cholesterol, uric acid, creatinine and low level of high dense lipoprotein (HDL). CONCLUSION: The history of clan, old age, overweight and higher fattiness were found risk factors of DM and IGT.

Adult↗
PubMed2000

[Risk factors of type 2 diabetes in Shenzhen].

OBJECTIVE: The study was designed to investigate the risk factors of Type 2 diabetes in the new city Shenzhen. METHODS: A representative sample of 8,182 adults aged over 20 to 75 years old were randomly selected in the residents of Shenzhen, China in 1997. Type 2 diabetes was diagnosed according to the WHO criteria. Questionnaire survey, anthropometric measurement and blood analysis were carried out, and logistic regression analysis was used to study the risk factors. RESULTS: The results showed that the prevalence of type 2 diabetes in subjects with high total cholesterol were 4.9 times of those with lower TC value. Subjects with high triglyceride had a prevalence 5.7 times of those who had lower TG. Those HDL-ch had a prevalence 68.7% higher than those with normal HDL-ch value; on the other hand, those HDL-ch > 1.91 mmol/L were 44.6% lower in the prevalence than those with normal HDL-ch. The prevalence of type 2 diabetes in subjects with BMI >or= 25 were 2.6 times of those with BMI < 25. Subject with hypertension (>or= 140/90 mm Hg) had a prevalence 3.8 times of those with normal blood pressure. Subjects with family history of type II diabetes had a prevalence 2.0 times of no family history, and women who had delivered babies over 4 kg had a prevalence 1.9 times of those who had babies less than 4 kg. Subjects with waist/hip ratio (WHR) >or= 1.0 had a prevalence 5.1 times of those with WHR < 1.0. The prevalence of type 2 Diabetes was higher with increasing amount of cigarette smoking and the duration (in years) of smoking or increasing drinking (alcohol) and the duration (in years) of drinking. CONCLUSIONS: The blood glucose level was found to be positively correlated with TC or TG, and negatively correlated with HDL-ch. This study demonstrated again that TC, TG, HDL-ch, obesity, hypertension, family history of type 2 diabetes and in women, delivery of babies over 4 kg and age were risk factors of type 2 diabetes.

Adult↗
PubMed2000

[Study on lipids and other volatile constituents in Pheretima aspergillum].

To study chemical constituents in Pheretima aspergillum, three kinds of fractions were obtained from this drug by soxhlet extraction with different solvents, and the chemical structures of thirty-six volatile components were identified by means of GC-MS. The eleven in ether fraction were all lipids and the relative content of non-saturated fatty acid was the highest(27.70%) such as oleic acid, linoleic acid, arachidonic acid and eicosatrienoic acid; There were eight lipids in acetone fraction (35.75%), which included one kind of nonsaturated fatty acid (linoleic acid); There were thirteen lipids in ethanol fraction (72.09%), which non-saturated fatty acid has never been detected. This study has determined the lipid composition in Pheretima aspergillum, especially non-saturated fatty acid, and afforded chemical base to cardio-cerebro-vascular therapy.

Animals↗
PubMed1999

Expression cloning of protein targets for 3-phosphorylated phosphoinositides.

The phosphatidylinositol 3-kinase (PI 3'-K) family of lipid kinases play a critical role in cell proliferation, survival, vesicle trafficking, motility, cytoskeletal rearrangements, and oncogenesis. To identify downstream effectors of PI 3'-K, we developed a novel screen to isolate proteins that bind to the major products of PI 3'-K: phosphatidylinositol-3,4-bisphosphate (PtdIns-3,4-P(2)) and PtdIns-3,4,5-trisphosphate (PtdIns-3,4,5-P(3)). This screen uses synthetic biotinylated analogs of these lipids in conjunction with libraries of radiolabeled proteins that are produced by coupled in vitro transcription/translation reactions. The feasibility of the screen was initially demonstrated using avidin-coated beads prebound to biotinylated PtdIns-3,4-P(2) and PtdIns-3,4,5-P(3) to specifically isolate the pleckstrin homology domain of the serine/threonine kinase Akt. We then demonstrated the utility of this technique in isolating novel 3'-phosphorylated phosphatidylinositol (3'-PPI)-binding proteins through the preliminary screening of in vitro transcribed/translated cDNAs from a small pool expression library derived from mouse spleen. Three proteins were isolated that bound specifically to 3'PPIs. Two of these proteins have been previously characterized as PIP3BP/p42(IP4) and the PtdIns-3,4,5-P(3)-dependent serine/threonine kinase phosphoinositide-dependent kinase 1. The third protein is a novel protein that contains only a Src homology 2 domain and a pleckstrin homology domain; this protein has a higher specificity for both PtdIns-3,4,5-P(3) and PtdIns-3,4-P(2) than for PtdIns-4, 5-bisphosphate. Transcripts of this novel gene are present in every tissue analyzed but are most prominently expressed in spleen. We have renamed this new protein PHISH for 3'-phosphoinositide-interacting Src homology-containing protein. This report demonstrates the utility of this technique for isolating and characterizing 3'-PPI-binding proteins and has broad applicability for the isolation of binding domains for other lipid products.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Cyclin K functions as a CDK9 regulatory subunit and participates in RNA polymerase II transcription.

Important progress in the understanding of elongation control by RNA polymerase II (RNAPII) has come from the recent identification of the positive transcription elongation factor b (P-TEFb) and the demonstration that this factor is a protein kinase that phosphorylates the carboxyl-terminal domain (CTD) of the RNAPII largest subunit. The P-TEFb complex isolated from mammalian cells contains a catalytic subunit (CDK9), a cyclin subunit (cyclin T1 or cyclin T2), and additional, yet unidentified, polypeptides of unknown function. To identify additional factors involved in P-TEFb function we performed a yeast two-hybrid screen using CDK9 as bait and found that cyclin K interacts with CDK9 in vivo. Biochemical analyses indicate that cyclin K functions as a regulatory subunit of CDK9. The CDK9-cyclin K complex phosphorylated the CTD of RNAPII and functionally substituted for P-TEFb comprised of CDK9 and cyclin T in in vitro transcription reactions.

Chromatography, Gel↗
PubMed1999

Design and synthesis of novel alpha(1)(a) adrenoceptor-selective antagonists. 4. Structure-activity relationship in the dihydropyrimidine series.

We have previously disclosed dihydropyridines such as 1a,b as selective alpha(1a) antagonists as a potential treatment for benign prostatic hyperplasia (BPH). The propensity of dihydropyridines toward an oxidation led us to find suitable replacements of the core unit. The accompanying papers describe the structure-activity relationship (SAR) of dihydropyrimidinones 2a,b as selective alpha(1a) antagonists. We report herein the SAR of dihydropyrimidines such as 4 and highlight the similarities and differences between the dihydropyrimidine and dihydropyrimidinone series of compounds.

Administration, Oral↗
PubMed1999

The Ig fold of the core binding factor alpha Runt domain is a member of a family of structurally and functionally related Ig-fold DNA-binding domains.

BACKGROUND: CBFA is the DNA-binding subunit of the transcription factor complex called core binding factor, or CBF. Knockout of the Cbfa2 gene in mice leads to embryonic lethality and a profound block in hematopoietic development. Chromosomal disruptions of the human CBFA gene are associated with a large percentage of human leukemias. RESULTS: Utilizing nuclear magnetic resonance spectroscopy we have determined the three-dimensional fold of the CBFA Runt domain in its DNA-bound state, showing that it is an s-type immunoglobulin (Ig) fold. DNA binding by the Runt domain is shown to be mediated by loop regions located at both ends of the Runt domain Ig fold. A putative site for CBFB binding has been identified; the spatial location of this site provides a rationale for the ability of CBFB to modulate the affinity of the Runt domain for DNA. CONCLUSIONS: Structural comparisons demonstrate that the s-type Ig fold found in the Runt domain is conserved in the Ig folds found in the DNA-binding domains of NF-kappaB, NFAT, p53, STAT-1, and the T-domain. Thus, these proteins form a family of structurally and functionally related DNA-binding domains. Unlike the other members of this family, the Runt domain utilizes loops at both ends of the Ig fold for DNA recognition.

Animals↗
PubMed1999

Arylpropane-1,3-diols in lignins from normal and CAD-deficient pines.

Significant quantities of arylopropane-1,3-diols have been identified in lignins isolated from a CAD-deficient pine mutant; smaller amounts are also present in lignins from normal pine. They arise from dihydroconiferyl alcohol via the action of peroxidases which are responsible for the radical generation steps of lignification. The structures in the complex lignin polymers are proven using 2D and 3D NMR of isolated lignin fractions.

Alcohol Oxidoreductases↗
PubMed1999

'Green revolution' genes encode mutant gibberellin response modulators.

World wheat grain yields increased substantially in the 1960s and 1970s because farmers rapidly adopted the new varieties and cultivation methods of the so-called 'green revolution'. The new varieties are shorter, increase grain yield at the expense of straw biomass, and are more resistant to damage by wind and rain. These wheats are short because they respond abnormally to the plant growth hormone gibberellin. This reduced response to gibberellin is conferred by mutant dwarfing alleles at one of two Reduced height-1 (Rht-B1 and Rht-D1) loci. Here we show that Rht-B1/Rht-D1 and maize dwarf-8 (d8) are orthologues of the Arabidopsis Gibberellin Insensitive (GAI) gene. These genes encode proteins that resemble nuclear transcription factors and contain an SH2-like domain, indicating that phosphotyrosine may participate in gibberellin signalling. Six different orthologous dwarfing mutant alleles encode proteins that are altered in a conserved amino-terminal gibberellin signalling domain. Transgenic rice plants containing a mutant GAI allele give reduced responses to gibberellin and are dwarfed, indicating that mutant GAI orthologues could be used to increase yield in a wide range of crop species.

Alleles↗
PubMed1999

Interactions between Tat and TAR and human immunodeficiency virus replication are facilitated by human cyclin T1 but not cyclins T2a or T2b.

The transcriptional transactivator (Tat) from the human immunodeficiency virus (HIV) does not function efficiently in Chinese hamster ovary (CHO) cells. Only somatic cell hybrids between CHO and human cells and CHO cells containing human chromosome 12 (CHO12) support high levels of Tat transactivation. This restriction was mapped to interactions between Tat and TAR. Recently, human cyclin T1 was found to increase the binding of Tat to TAR and levels of Tat transactivation in rodent cells. By combining individually with CDK9, cyclin T1 or related cyclins T2a and T2b form distinct positive transcription elongation factor b (P-TEFb) complexes. In this report, we found that of these three cyclins, only cyclin T1 is encoded on human chromosome 12 and is responsible for its effects in CHO cells. Moreover, only human cyclin T1, not mouse cyclin T1 or human cyclins T2a or T2b, supported interactions between Tat and TAR in vitro. Finally, after introducing appropriate receptors and human cyclin T1 into CHO cells, they became permissive for infection by and replication of HIV.

Animals↗
PubMed1999

Prolongation of rat heart allograft survival with K(+)ATP-dependent channel modulators.

Controversies exist regarding the immunoregulatory properties of K(+) ATP channel modulators. We investigated the effects of aprikalim, a K(+) ATP-dependent channels activator, and glibenclamide and gliclazide, two inhibitors of K(+) ATP-dependent channels, on the prolongation of heart allograft survival in the rat. Nine groups (n >/= 5) were involved in this study with the Brown-Norway to Lewis rat combination treated with aprikalim, glibenclamide, gliclazide, and/or cyclosporine. The results indicate that modulators of K(+) ATP-dependent channels can improve the survival of rat heart allograft without interfering with the immunosuppressive properties of cyclosporine.

Animals↗
PubMed1999

Improved techniques for kidney transplantation in the monkey.

Improved microsurgical techniques for kidney transplantation in the monkey are described. The left graft kidney is transplanted to the lower part of abdomen with end-to-side anastomoses of renal artery to aorta without a patch of aorta, renal vein to inferior vena cava, and end-to-end anastomosis of donor and recipient ureter with 8-0 nylon sutures in a bilateral nephrectomized recipient monkey. We recently performed 60 kidney transplantations in Vervet monkeys. None died of surgery or surgical complications. This reproducible model provides a useful tool to test new immunosuppressants and to investigate the mechanism of drug-induced tolerance and xenotransplantation in primates as a support to clinical trial.

Animals↗
PubMed1999

Synergistic effect of rapamycin and cyclosporine in prevention of acute kidney allograft rejection in the mouse.

The effect of rapamycin (RAPA) and cyclosporine A (CsA) monotherapy and combination therapy was examined in prevention of kidney allograft rejection in the mouse. Both drugs were administered orally for up to 14 days in BALB/c (H-2(d)) to C57BL/6 (H-2(b)) mice strong combination. Six groups were treated with RAPA and/or CsA. This study shows that concomitant therapy of RAPA and CsA produces strong synergistic interaction in prolonging renal allograft survival in mice when compared with monotherapy of RAPA or CsA.

Animals↗
PubMed1999

A baculovirus enhancin alters the permeability of a mucosal midgut peritrophic matrix from lepidopteran larvae.

The peritrophic matrix (PM) in lepidopterous larvae may function as a defensive barrier against ingested viral pathogens. PMs isolated from Trichoplusia ni and Pseudaletia unipuncta larvae, were treated with a baculovirus-encoded metalloprotease (enhancin) from Trichoplusia ni granulosis virus (TnGV) and their in vitro permeability to blue dextran and fluorescent-labelled Autographa californica nuclear polyhedrosis virus (AcMNPV) was determined using a dual chamber permeability apparatus. Incubation of T. ni PMs with 0.0, 0.5, 1.0, and 2.0mg/ml enhancin resulted in a blue dextran 2000 flux of 4.4, 6.3, 9.9, and 15.6&mgr;g/mm(2)/h, respectively. In addition, T. ni PMs treated with enhancin were found to be significantly more permeable to fluorescent-labelled AcMNPV than non-treated control PMs. The permeability of T. ni PMs treated with 3.0mg/ml enhancin was 0.017 cumulative percent crossing/mm(2)/h, whereas the permeability of the control PM was below the detectable limit. Similarly, enhancin treatment greatly increased the permeability of P. unipuncta PMs to AcMNPV. These results provide evidence that the PM from two lepidopteran species can block the passage of baculovirions across this matrix thus reducing the probability of larval infection. Furthermore, these results support the hypothesis that enhancin facilitates NPV infection of larvae by altering the permeability of the PM.

Journal Article↗
PubMed1999

Are lignins optically active?

The accepted derivation of lignins from non(enzymatically)-controlled radical coupling reactions has been recently challenged, and it is relevant to ascertain unequivocally whether lignins are or are not (as normally assumed) optically active. Two approaches were used. First, DFRC (derivatization followed by reductive cleavage) dimers derived from beta-5- and beta-beta-units in pine lignins, which certainly retain unaltered chiral centers (as well as beta-1- and beta-O-4-units where the intactness may be debated), were shown to be optically inactive by circular dichroism (CD) and chiral high-performance liquid chromatography. CD of beta-5-derived dimers following enantiomeric separation readily demonstrated the sensitivity of the method. Second, no optical activity could be detected (above 250 nm to avoid carbohydrate contributions) by CD of lignin isolates from pine, kenaf, maize, or a CAD-deficient pine mutant. Representative lignins are therefore not, within limits of detection by these methods, optically active.

Carbohydrate Conformation↗
PubMed1999

Is there a reduced risk of breast cancer among women with hip fractures?

To test the hypothesis that osteoporosis, which results partly from long-term estrogen deficiency, is associated with a lowered risk of breast cancer, a population-based cohort study was performed in Amiens. To ascertain the incidence of breast cancer, 1300 women were followed through after a first hip fracture. Overall, 18 cases of cancer were observed cf. 21.8 expected (standardized incidence ratio (SIR): 0.82; 95% confidence interval (CI): 0.5-1.3). The results are consistent with previous studies which concluded that long-term estrogen deficiency is associated with a reduced risk of developing breast cancer.

Aged↗