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Biomedical subjects

H Peng

Publications and source records attributed to H Peng.

7 recordsLinked to original sources
PubMed1992

Restriction mapping and localization of GL-7-ACA acylase gene.

This paper presents the results about the restriction mapping of recombinant plasmids pMR5 and pMR6 containing GL-7-ACA acylase gene from Pseudomonas sp. 130, gene localization and its expression under the control of different promoters, tet, tac or lac/tac, in Escherichia coli. The analysis of gel electrophoresis of pMR5 cleaved with several kinds of restriction enzymes indicated that there is no sites of EcoRI, HindIII and ClaI but the presence of following sites: one HpaI, two XhoI, three EamHI and four PstI on the cloned gene fragment. The restriction maps of pMR5 and pMR6 were determined by comparative digestion of various endonucleases. The gene of GL-7-ACA acylase was localized on a 3.0kb fragment of B2-B3-HpaI from the studies on a serial subcloning. Expression of subclones pMR9, pMR10 and pMR11 in E. coli was compared. Higher yield of acylase was obtained when the gene fragment was placed downstream of the tac promoter. The expression of Pseudomonas gene in E. coli was also discussed.

Amidohydrolases↗
PubMed1991

[The production of human monoclonal antibodies against Pseudomonas aeruginosa by human-mouse hybridoma technique].

The fusion of peripheral B lymphocytes from human immunized with P. aeruginosa polyvalent vaccine and mouse myeloma cell line SP2/0 was successfully performed. The rate of fusion was 74%(71/96) and the positive rate of antibody was 19.7%. Two hybridoma cell lines (A3 and F8) secreting McAb against P. aeruginosa were obtained after three times cloning by limiting dilution. The human chromosomes together with mouse chromosomes were discovered in karyotype assay of the hybrids. A3 and F8McAbs were human IgG by class determination. These MrcAbs could recognize 43 kd and 36 kd MW specific components of P. aeruginosa antigen by enzyme linked immuno-transfer blot technique.

Animals↗
PubMed1990

[Production and characterization of anti-human hepatocellular carcinoma monoclonal antibodies].

The hepatocellular carcinoma (HCC) cell line, QGY-7703, derived from a Chinese patient, was used to immunize the BALB/c mice. Fifteen hybridomas producing McAb that reacted with QGY-7703 cells were isolated from 858 hybridomas created in three cell fusions. In further studies two McAb, namely, AQGY1 and A-QGY2, were selected which specifically stained HCC cells grown in vitro. The reactivity of these McAb was not removed by the absorption by homogenates of the normal liver, but was by homogenates of HCC cells. A-QGY1 and A-QGY2 also reacted definitely with HCC cells in liver tissues of HCC patients, but neither with other cells in the tissues nor with nontransformed liver tissues of the same patients. Furthermore these two McAb stained the adult or fetal liver tissues, nor all of the other normal or tumor tissues that had been tested. Blocking and absorbing experiments revealed that A-QGY1 and AQGY2 antigens had no immunohomogenicity with antigens such as HBsAg, HBcAg, HBeAg, AFP and CEA. The specificity of these two McAb may be used potentially for the sero diagnosis, histologic identification, radioimmunoimaging and destruction of human hepatocellular carcinoma.

Antibodies, Monoclonal↗
PubMed1990

[The effect of pollen in enhancing tolerance to hypoxia and promoting adaptation to highlands].

Mixed pollen containing four sorts of pollens (Rape, Typhae, Corn, Sunflower) has been proved to have many biology effects. It is capable of increasing body tolerance to acute hypoxia and promoting adaptation to highlands. The experimental study showed that pollen can significantly increase body tolerance to acute hypoxia pollen can also increase the high energy content and normalize the activity of several enzymes which are important to high energy metabolism; regulate the neurotransmitter in 4 parts of the brain and maintain normal activities in the nervous system; increase the secretion of adrenocortical hormone which may favour O2 absorption; increase SOD content in tissues (heart, liver) and hence may prevent super-oxygenation and guard against free radicals, increase PO2 in the brain and arterial blood; decrease oxygen consumption and blood lactic acid concentration; and increase the immunity of animals under normal condition. Pollen has neither acute nor chronic toxicity and causes no allergic reaction. In field study, pollen can also reduce and ameliorate symptoms of acute mountain sickness in human beings.

Adaptation, Physiological↗
PubMed1988

Retroviral-mediated gene transfer and expression of human phenylalanine hydroxylase in primary mouse hepatocytes.

Genetic therapy for phenylketonuria (severe phenylalanine hydroxylase deficiency) may require introduction of a normal phenylalanine hydroxylase gene into hepatic cells of patients. We report development of a recombinant retrovirus based on the N2 vector for gene transfer and expression of human phenylalanine hydroxylase cDNA in primary mouse hepatocytes. This construct contains an internal promoter of the human alpha 1-antitrypsin gene driving transcription of the phenylalanine hydroxylase cDNA. Primary mouse hepatocytes were isolated from newborn mice, infected with the recombinant virus, and selected for expression of the neomycin-resistance gene. Hepatocytes transformed with the recombinant virus contained high levels of human phenylalanine hydroxylase mRNA transcripts originating form the retroviral and internal promoters. These results demonstrate that the transcriptional regulatory elements of the alpha 1-antitrypsin gene retain their tissue-specific function in the recombinant provirus and establish a method for efficient transfer and high-level expression of human phenylalanine hydroxylase in primary hepatocytes.

Animals↗
PubMed1988

Shape estimation in computer tomography from minimal data.

In computerized tomography, line integrals of the absorptivity are used to reconstruct the object. In some applications only the locations, sizes, and shapes of internal opacities or near-opacities are needed. For these applications it is unnecessary to reconstruct an image by convolution backprojection [O(N3)] or by direct Fourier methods [O(N2log N)]. We propose an algorithm suitable for this problem that requires only O(N) operations (N is of the order of the number of views). We analyze and demonstrate the high performance of the algorithm but show that the performance of the algorithm depends strongly on an appropriate choice of system parameters. These parameters, the number of view N theta, and the detector spacing deltas are shown to be linked, and a choice of deltas strongly constrains the choice of N theta. We show how an optimum N theta can be determined for a fixed deltas, including practical values of deltas. A series of experiments that reinforce the theory is simulated on a computer.

Humans↗