101
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Chang JW, Peng M, Vaquerano JE, Zhou YM, Clinton RA, Hyun WC, Giedlin MA, Leong SP. Induction of Th1 response by dendritic cells pulsed with autologous melanoma apoptotic bodies. Anticancer Res 2000; 20:1329-36. [PMID: 10928040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
BACKGROUND We hypothesize that dendritic cells (DCs) can process antigens from autologous melanoma apoptotic bodies (MABs) and induce effector T cells in melanoma patients. MATERIALS AND METHODS Peripheral blood mononuclear cells were obtained from three stage IV melanoma patients and adherent cells were cultured in complete medium (CM) containing GM-CSF (800 U/ml) and IL-4 (1000 U/ml) for 7 days. Autologous MABs from melanoma cells following actinomycin D treatment (0.5 microgram/ml) for 24 hours, were added to 72 hour DC culture. Autologous effector T cells were cultured in CM containing 60 IU/ml of IL-2 and were stimulated by MAB-pulsed DCs three times at a weekly interval. Effector T cells were harvested at the end of third cycle of DC stimulation. RESULTS Using ELISPOT, IFN-gamma production by effector T cells stimulated by MAB-pulsed DCs was significantly higher than that by T cells without DC stimulation. Microscopy demonstrated phagocytosis of MABs by DCs. CONCLUSIONS MAB-pulsed DCs are capable of stimulating Th1-directed autologous effector T cells. Pulsing DCs with autologous MABs may be a novel approach in future DC-based immunotherapeutic trials.
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102
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Xu X, Peng M, Fang Z. The direction of microsatellite mutations is dependent upon allele length. Nat Genet 2000; 24:396-9. [PMID: 10742105 DOI: 10.1038/74238] [Citation(s) in RCA: 231] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Microsatellites, comprising tandemly repeated short nucleotide sequences, are ubiquitous in eukaryotic genomes. Mutations within microsatellites are frequent, altering their overall length by insertion or deletion of a small number of repeat units, with a rate as high as 10(-3) in humans. Despite their high mutability, stable allele frequency distributions are typically observed for microsatellites in humans as well as other primates, although the mechanism maintaining these stable distributions remains unclear. Previous studies have suggested that microsatellite mutations occur more frequently in longer alleles and favour expansion. Generalizing these results has been hindered because the sample sizes were small, only a small subset of alleles for any marker was studied and the direction of mutation (expansion or contraction) was not rigorously determined. Here we examine 236 mutations at 122 tetranucleotide repeat markers and find that the rate of contraction mutations increases exponentially with allele size, whereas the rate of expansion mutations is constant across the entire allele distribution. The overall rate of expansion mutations does not differ from that of contractions. Our findings offer an explanation for the stationary allele distribution of microsatellites.
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103
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Petrulis A, Peng M, Johnston RE. The role of the hippocampal system in social odor discrimination and scent-marking in female golden hamsters (Mesocricetus auratus). Behav Neurosci 2000; 114:184-95. [PMID: 10718273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Female golden hamsters (Mesocricetus auratus) received aspiration lesions of the parahippocampal region (PARA) or electrolytic lesions of the fimbria-fornix (FNX) and were tested for their (a) discrimination between odors of individual males in a habituation-discrimination task, (b) preference for male over female odors, and (c) scent-marking in response to conspecific odors. Both lesion groups habituated to repeated presentations of a male's odor. However, only FNX females discriminated between scents of individual males, whereas PARA females did not. Neither lesion eliminated female preferences for male odors. Females with FNX lesions showed decreased levels of scent marking, but those with PARA lesions had more subtle deficits. Thus, the PARA, but not the subcortical connections of the hippocampus, is critical for discrimination of the odors of individuals.
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104
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Peng M, Zhou Q. [Determination of eight trace elements in kadsura coccinea by flame atomic absorption spectrophotometry]. GUANG PU XUE YU GUANG PU FEN XI = GUANG PU 2000; 20:89-90. [PMID: 12953461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In this paper, we used the flame atomic absorption spectrophotometry to determine the contents of Zn, Fe, Ca, Cu, K, Na, Mn, Mg in the kadsura coccinea. We assayed the determination conditions systematically. The SrCl2 was sued to eliminate coexisting elements. And we achieved the purpose that we can determine a lot of elements in the same liquor at the same time. It shows that this method is simple, convenient and accurate.
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105
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Yassa NA, Peng M, Ralls PW. Perirenal lucency ("kidney sweat"): a new sign of renal failure. AJR Am J Roentgenol 1999; 173:1075-7. [PMID: 10511182 DOI: 10.2214/ajr.173.4.10511182] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE This study describes a new sonographic finding in renal failure: perirenal lucency, which we call the "kidney sweat" sign. MATERIALS AND METHODS During 1 year at our institution, 502 renal sonograms were obtained. Sonography evaluated 330 patients with renal failure. All of the examinations were retrospectively analyzed. RESULTS An extracapsular hypoechoic rim was present in 47 (14%) of the 330 patients with renal failure. The finding, when present, was always bilateral. The hypoechoic rim was not present in the remaining 283 patients with renal failure. Forty (85%) of the 47 patients had kidneys that were hyperechoic compared with the liver. Twenty-eight (60%) of the 47 patients had kidneys that were hyperechoic compared with the spleen. In 15 (32%) of the 47 patients, the kidneys were small. Ascites was present in 11 (23%) of the 47 patients. Of the 283 patients with renal failure whose sonograms did not show the hypoechoic rim, 76 patients had normal sonographic findings. The remaining 207 patients with renal failure who did not show the kidney sweat sign had hydronephrosis, stones, cysts, echogenic kidneys, small kidneys, or ascites. CONCLUSION An extracapsular hypoechoic rim is found in patients with renal failure. We call this finding "kidney sweat." We believe, but cannot currently prove, that the kidney sweat sign represents edema. It is an additional sonographic finding in patients with renal failure.
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106
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Shaing K, Aydemir A, Cheng E, Peng M. Self-sustained steady state tokamak plasmas. FUSION ENGINEERING AND DESIGN 1999. [DOI: 10.1016/s0920-3796(99)00009-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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107
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Liu C, Li Y, Peng M, Laties AM, Wen R. Activation of caspase-3 in the retina of transgenic rats with the rhodopsin mutation s334ter during photoreceptor degeneration. J Neurosci 1999; 19:4778-85. [PMID: 10366612 PMCID: PMC6782664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
The role of caspase-3 in photoreceptor degeneration was examined in a line of transgenic rats that carry a rhodopsin mutation S334ter. Photoreceptor degeneration in these animals is rapid. It is detected as early as postnatal day (PD) 8, and by PD 20, only one of the original 12 rows of nuclei remain in the outer nuclear layer. At PD 11 and 12, the number of photoreceptors dying per day reaches a peak of approximately 30% of the total photoreceptors in the retina. Coincident with this rapid degeneration is an increase in caspase-3-like activity as assessed by the cleavage of a fluorescent substrate N-acetyl-Asp-Glu-Val-Asp-aminomethylcoumarin and an increase in activated caspase-3 as determined by Western blot analysis for its 12 kDa subunit. Intraocular injection of an irreversible caspase-3 inhibitor N-benzyloxycarbonal-Asp(OMe)-Glu(OMe)-Val-Asp(Ome)-fluoromethyk etone partially protected photoreceptors from degeneration. These findings indicate that a caspase-3-dependent mechanism is operative in photoreceptor death in the transgenic rats under investigation.
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108
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Chang JW, Vaquerano JE, Zhou YM, Peng M, Leong SP. Characterization of dendritic cells generated from peripheral blood of patients with malignant melanoma. Anticancer Res 1999; 19:1815-20. [PMID: 10470120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Dendritic cells (DCs) are professional antigen presenting cells. Two x 10(7) peripheral blood mononuclear cells (PBMCs) from each of 6 melanoma patients and 4 normal donors were incubated in 6-well plates. The adherent cells were cultured in GM-CSF (800 U/ml) and IL-4 (1000 U/ml) for 10 days. Anti-CD80, anti-CD86, anti-HLA-DR, anti-HLA-class I monoclonal antibodies and supernatant from two melanoma cell lines were incubated with DCs before responder T cells were added in mixed lymphocyte reaction (MLR). The mean yields of DCs were 3.6 x 10(5) and 9.3 x 10(5) for donor and the melanoma patients respectively. MLR was inhibited by anti-CD80, anti-CD86, anti-HLA-DR, anti-HLA-Class I and supernatant of melanoma cultures. The characteristics of DCs generated from melanoma patients were comparable to those from donors. DC function was inhibited by soluble factors in melanoma cultures. Further studies are warranted to characterize these inhibitory factors.
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109
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Peng M, Gao M, Abdel-Aal ESM, Hucl P, Chibbar RN. Separation and Characterization of A- and B-Type Starch Granules in Wheat Endosperm. Cereal Chem 1999. [DOI: 10.1094/cchem.1999.76.3.375] [Citation(s) in RCA: 215] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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110
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Petrulis A, Peng M, Johnston RE. Effects of vomeronasal organ removal on individual odor discrimination, sex-odor preference, and scent marking by female hamsters. Physiol Behav 1999; 66:73-83. [PMID: 10222476 DOI: 10.1016/s0031-9384(98)00259-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Removal of the vomeronasal organ (VNX) did not eliminate the ability of female hamsters to discriminate between individual male's flank gland or urine odors in a habituation/discrimination task nor did it impair preference for male odors over female odors from a distance. Vomeronasal organ removal did reduce overall levels of investigation of flank gland odor in the habituation/discrimination task. Although VNX females did not show severe impairments in the frequency of either flank or vaginal marking in response to odors, they did show an abnormal pattern of marking. VNX females, unlike shams, did not flank mark more to female odors than to male odors, nor did they vaginal mark more to male odors than to female odors. Thus, the vomeronasal organ in female hamsters appears to be important for differences in scent marking toward male and female odors, but is not essential for discrimination of individual odors or for preferences for male over female odors.
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111
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Peng M, Wolyn D. DEVELOPMENT OF A MICROSPORE CULTURE METHOD TO PRODUCE HAPLOID AND DOUBLED-HAPLOID ASPARAGUS (ASPARAGUS OFFICINALIS L.) PLANTS. ACTA ACUST UNITED AC 1999. [DOI: 10.17660/actahortic.1999.479.49] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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112
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Vaquerano JE, Peng M, Chang JW, Zhou YM, Leong SP. Digital quantification of the enzyme-linked immunospot (ELISPOT). Biotechniques 1998; 25:830-4, 836. [PMID: 9821585 DOI: 10.2144/98255st04] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Enzyme-linked immunospot (ELISPOT) is a sensitive technique for the detection of cytokines released by immune cells. The technique is well established and correlates closely with the enzyme-linked immunosorbent assay (ELISA) technique. Here, we introduce an integrated imaging-analysis system to quantitate the spots formed by the ELISPOT assay. The spots can be easily counted when the background is clear and the spots are few. However, when the number of spots increases to > 100, this task becomes challenging and time-consuming. To minimize time and standardize the counting procedure, we have used a digital camera linked to a computer system for reading the plates. In general, the computer is able to count more spots and has a smaller standard deviation when compared with the manual microscopic count. This integrated system is commercially available, and we believe that this method is objective, time-saving and consistent in routine ELISPOT assay counting, especially when numerous spots are present.
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113
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Peng M, Li Y, Luo Z, Liu C, Laties AM, Wen R. Alpha2-adrenergic agonists selectively activate extracellular signal-regulated kinases in Müller cells in vivo. Invest Ophthalmol Vis Sci 1998; 39:1721-6. [PMID: 9699562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
PURPOSE Alpha2-adrenergic agonists have specific and selective effects on the retina to induce expression of basic fibroblast growth factor and to protect photoreceptors. This work explores the signaling pathway that mediates these effects. METHODS Alpha2-adrenergic agonists xylazine and clonidine were administered systemically to male adult Sprague-Dawley rats. The activation state of extracellular signal-regulated kinases (ERKs) in the retina was assessed by immunoblot analysis, using antibodies that specifically recognize the dually phosphorylated forms of p44/p42 ERKs. Localization of phosphorylated ERKs was determined by immunocytochemistry. RESULTS Intramuscular injection of 6 mg/kg xylazine induced an increase in ERK phosphorylation in the retina within 30 minutes that lasted 3 hours. Xylazine induced ERK phosphorylation at 1 mg/kg and reached a maximum at 10 mg/kg. Injection of clonidine also induced ERK phosphorylation in the retina. Yohimbine, a specific alpha2-adrenergic antagonist, completely prevented the induction of ERK phosphorylation. Immunocytochemical studies showed that the increase in ERK phosphorylation occurred mainly in Müller cells. In the brain, xylazine injection resulted in a decrease in ERK phosphorylation. CONCLUSIONS Our results indicate that systemically administered alpha2-adrenergic agonists selectively activate ERKs in retinal Müller cells. The induced activation of ERKs in Müller cells is probably one of the early events that result in photoreceptor protection. These results also indicate that Müller cells are unique in response to alpha2-adrenergic agonists and imply a role for Müller cells in alpha2-adrenergic agonist-induced photoreceptor protection.
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114
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Peng M, Zhang Y, Xue Z, Han Q. [Alpha1-adrenoceptor subtypes in rabbit penile corpus cavernosum]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 1998; 36:497-9. [PMID: 11825451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To study alpha(1)- adrenoceptor (alpha(1)- AR) subtypes with the functional role and the distribution of its subtypes in rabbit penile corpus cavernosum. METHOD The rabbit penile corpus cavernosum was studied by using functional experiment and radioligand binding assay. RESULT In the radioligand binding assay, the maximal binding capacity (Bmax of (125)IBE and alpha(1)-AR) decreased obviously after pretreatment with chloroethylclonidine (CEC), which were 746 +/- 236 fmol/mg protein and 214 +/- 71 fmol/mg protein, respectively. Alpha(1A)-, alpha(1D)-and alpha(1B)-AR took about 20%, 25% and 55%, respectively. In the functional experiments, the maximal contraction induced by norepinephrine (NE) was not decreased significantly after pretreatment with CEC. The pA(2) values of two alpha(1)-AR selective antagonists, 5-MU, BMY7378, for antagonizing NE-induced penile corpus cavernosum contraction had a high correlative association with the pK(I) values for cloned alpha(1A)-AR. CONCLUSION The functional alpha(1)-AR subtype is alpha(1A)-AR although there are three subtypes in the penile corpus cavernosum.
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115
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Peng M, Conforti L, Millhorn DE. Expression of somatostatin receptor genes and acetylcholine receptor development in rat skeletal muscle during postnatal development. Int J Mol Med 1998; 1:841-8. [PMID: 9852305 DOI: 10.3892/ijmm.1.5.841] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Our laboratory reported previously that somatostatin (SST) is transiently expressed in rat motoneurons during the first 14 days after birth. We investigated the possibility that the SST receptor (SSTR) is expressed in skeletal muscle. We found that two of the five subtypes of SSTR (SSTR3 and SSTR4) are expressed in skeletal muscle with a time course that correlates with the transient expression of SST in motoneurons. In addition, SSTR2A is expressed from birth to adulthood in skeletal muscle. Both SSTR2A and SSTR4 are also expressed in L6 cells, a skeletal muscle cell line. Somatostatin acting through its receptors has been shown to stimulate tyrosine phosphatase activity in a number of different tissues. We found that several proteins (50, 65, 90, 140, 180 and 200 kDa) exhibited a reduced degree of tyrosine phosphorylation following SST treatment. Inhibition of tyrosine phosphatase activity with sodium orthovanadate increased expression of the nicotinic acetyl-choline receptor (nAChR) epsilon subunit mRNA by three fold. Somatostatin reversed the elevated epsilon mRNA following orthovanadate treatment. These findings show that SSTR is expressed in skeletal muscle and that SST acting via the SSTR regulates tyrosine phosphorylation and expression of the epsilon subunit of the AChR in the rat skeletal muscle.
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MESH Headings
- Animals
- Blotting, Northern
- Cell Line
- Gene Expression Regulation, Developmental
- Hindlimb
- Muscle Development
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/growth & development
- Muscle, Skeletal/metabolism
- Phosphorylation
- RNA, Messenger/biosynthesis
- Rats
- Receptors, Cholinergic/biosynthesis
- Receptors, Cholinergic/genetics
- Receptors, Somatostatin/genetics
- Receptors, Somatostatin/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Somatostatin/pharmacology
- Tyrosine/metabolism
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116
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Tsygankova OM, Peng M, Maloney JA, Hopkins N, Williamson JR. Angiotensin II induces diverse signal transduction pathways via both Gq and Gi proteins in liver epithelial cells. J Cell Biochem 1998; 69:63-71. [PMID: 9513047 DOI: 10.1002/(sici)1097-4644(19980401)69:1<63::aid-jcb7>3.0.co;2-t] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Angiotensin II stimulates a biphasic activation of Raf-1, MEK, and ERK in WB liver epithelial cells. The first peak of activity is rapid and transient and is followed by a sustained phase. Angiotensin II also causes a rapid activation of p21ras in these cells. Moreover, two Src family kinases (Fyn and Yes) were activated by angiotensin II in a time- and concentration-dependent manner. Microinjection of antibodies against Fyn and Yes blocked angiotensin II-induced DNA synthesis and c-Fos expression in WB cells, indicating an obligatory involvement of these tyrosine kinases in the activation of the ERK cascade by angiotensin II. Finally, substantial reduction of the angiotensin II-stimulated activation of Fyn, Raf-1, ERK, and expression of c-Fos by pertussis toxin pretreatment argues that G proteins of the Gi family as well as the Gq family are involved in angiotensin II-mediated mitogenic pathways in WB cells.
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117
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Peng M, Abribat T, Calvo E, LeBel D, Palin MF, Bernatchez G, Morisset J, Pelletier G. Ontogeny of insulin-like growth factors (IGF), IGF binding proteins, IGF receptors, and growth hormone receptor mRNA levels in porcine pancreas. J Anim Sci 1998; 76:1178-88. [PMID: 9581943 DOI: 10.2527/1998.7641178x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We examined the ontogeny of mRNA levels of IGF-I and -II, IGF type 1 (IGFI-R) and type II receptors (IGFII-R), IGF binding protein-1 and -3 (IGFBP-1 and -3), GH receptor (GHR), and tissue concentrations of IGF and IGFBP in the pancreas of pigs. Tissues were collected from fetuses at 90 and 110 d of gestation and from pigs at 1, 21, 90 and 180 d of age. Northern blots were performed using total RNA hybridized with 32P-labeled cDNA probes (human IGF-I and human IGFI-R) and cRNA probes (rat IGF-II, human IGFII-R, human IGFBP-1, pig IGFBP-3, and pig GHR). There were two accelerated growth stages of the pancreas: the first one at 90 d of fetal life, which is characterized by cell hyperplasia (high ratio of DNA to body weight), and the second one at postnatal 90 d, which is attributed to cell hypertrophy (high ratios of pancreatic weight, RNA, and protein to DNA). The level of IGF-II mRNA and its tissue concentration were predominant during fetal life and low thereafter. The IGF-I mRNA level was high during fetal and early postnatal life and decreased thereafter. Messenger RNA levels of IGFI-R, IGFBP-3, and GHR and concentrations of IGFBP-1 and -2 were abundant during fetal and early postnatal life. In conclusion, IGF may be involved in various physiological periods of pancreatic development in pigs.
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MESH Headings
- Aging/genetics
- Aging/metabolism
- Aging/physiology
- Animals
- Base Sequence
- Blotting, Northern
- DNA/analysis
- DNA Primers/chemistry
- Female
- Gene Expression Regulation, Developmental/genetics
- Humans
- Insulin-Like Growth Factor Binding Proteins/analysis
- Insulin-Like Growth Factor Binding Proteins/genetics
- Insulin-Like Growth Factor Binding Proteins/metabolism
- Male
- Organ Size/physiology
- Pancreas/chemistry
- Pancreas/embryology
- Pancreas/physiology
- Proteins/analysis
- RNA/analysis
- RNA, Messenger/analysis
- RNA, Messenger/genetics
- Receptor, IGF Type 1/analysis
- Receptor, IGF Type 1/genetics
- Receptor, IGF Type 1/metabolism
- Receptors, Somatotropin/analysis
- Receptors, Somatotropin/genetics
- Receptors, Somatotropin/metabolism
- Somatomedins/analysis
- Somatomedins/genetics
- Somatomedins/metabolism
- Swine/embryology
- Swine/genetics
- Swine/metabolism
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118
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Kowalska MA, Tan L, Holt JC, Peng M, Karczewski J, Calvete JJ, Niewiarowski S. Alboaggregins A and B. Structure and interaction with human platelets. Thromb Haemost 1998; 79:609-13. [PMID: 9531050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Viper venoms contain a variety of platelet binding proteins including those which bind to platelet GPIb/GPIX. Most of these proteins inhibit von Willebrand factor mediated platelet agglutination. Here we report the primary structures of unique members of this family, alboaggregins A and B, isolated from Trimeresurus albolabris, which have the ability to stimulate platelet agglutination and aggregation. Four chains of alboaggregin A and two chains of alboaggregin B share a high degree of homology and all cysteines in both alboaggregins are conserved. Both alboaggregins caused similar agglutination of fixed platelets. Alboaggregin A induced platelet aggregation and release reaction with EC50 = 10 and 30 nM, respectively, which is 20-fold lower than those for alboaggregin B. These observations suggest that the dimeric structure of alboaggregin B is sufficient to mediate its binding to GPIb and induce agglutination of platelets whereas aggregation and release reaction are significantly enhanced by tetrameric structure of alboaggregin A.
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119
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Liu C, Peng M, Laties AM, Wen R. Preconditioning with bright light evokes a protective response against light damage in the rat retina. J Neurosci 1998; 18:1337-44. [PMID: 9454843 PMCID: PMC6792743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Constant exposure to bright light induces photoreceptor degeneration and at the same time upregulates the expression of several neurotrophic factors in the retina. At issue is whether the induced neurotrophic factors protect photoreceptors. We used a preconditioning paradigm to show that animals preconditioned with bright light became resistant to subsequent light damage. The preconditioning consisted of a 12-48 hr preexposure, followed by a 48 hr "rest phase" of normal cyclic lighting. The greatest protection was achieved by a 12 hr preexposure. Preconditioning induces a prolonged increase in two endogenous neurotrophic factors: basic fibroblast growth factor (bFGF) and ciliary neurotrophic factor (CNTF). It also stimulates the phosphorylation of extracellular signal-regulated protein kinases (Erks) in both photoreceptors and Müller cells. These findings indicate that exposure to bright light initiates two opposing processes: a fast degenerative process that kills photoreceptors and a relatively slower process that leads to the protection of photoreceptors. The extent of light damage, therefore, depends on the interaction of the two processes. These results also suggest a role of endogenous bFGF and CNTF in photoreceptor protection and the importance of Erk activation in photoreceptor survival.
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Liu M, Peng M, Liu M. [The experimental study of the effect of insulin and danshen on culture of fibroblast in vitro]. ZHONGGUO XIU FU CHONG JIAN WAI KE ZA ZHI = ZHONGGUO XIUFU CHONGJIAN WAIKE ZAZHI = CHINESE JOURNAL OF REPARATIVE AND RECONSTRUCTIVE SURGERY 1998; 12:52-4. [PMID: 10374625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
UNLABELLED To investigate the effect of Insulin and Danshen on anabolism and catabolism of collagen during the healing of wound, fibroblast which was cultured from human embryonic skin were divided into 3 groups: Insulin group, Danshen group and contral group. Each group was cultured for 2, 4 and 6 days, then the growth curve was established respectively. RESULTS 1. The growth curve showed-insulin group > control group > Danshen group. 2. The rate of cell division in 3 groups was 19.6/1000, 2.5/1000, 3.77/1000 respectively. 3. The electron microscopic scanning showed that there was much of fibroid tissue surrounding the fibroblast cell in insulin group, but there was little fibroid tissue in Danshen group. The conclusion showed that insulin can accelerates proliferation of fibroblast and synthesis of collagen, but the effect of denshen was just on the contrary.
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Guo YL, Peng M, Kang B, Williamson JR. Inhibition of thrombin-stimulated cell proliferation by ceramide is not through inhibition of extracellular signal-regulated protein kinase. Biochem Biophys Res Commun 1997; 240:405-8. [PMID: 9388491 DOI: 10.1006/bbrc.1997.7669] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Activation of the thrombin receptor provides a strong mitogenic signal in CCL39 cells. Ceramide was found to inhibit thrombin-mediated mitogenesis in these cells while dihydroceramide had no effect. Many growth inhibitors exert their effect by inhibiting extracellular signal-regulated kinase (ERK) signaling pathway. However, neither ceramide nor dihydroceramide blocked the thrombin-induced activation of ERK. In contrast, both agents potentiated ERK activity. The expression of c-fos, c-jun and cyclin D1, which are downstream of ERK in the mitogenic pathway were stimulated by thrombin but this stimulation was not affected by ceramide or dihydroceramide. Therefore, the ceramide inhibition of thrombin-stimulated cell growth in CCL39 cells does not appear to be mediated by an effect on the activation of ERK. Furthermore, the data also suggest that the separate effects of ceramide on thrombin-stimulated cell growth and ERK activity are mediated by different mechanisms.
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122
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Peng M, Palin MF, Véronneau S, LeBel D, Pelletier G. Ontogeny of epidermal growth factor (EGF), EGF receptor (EGFR) and basic fibroblast growth factor (bFGF) mRNA levels in pancreas, liver, kidney, and skeletal muscle of pig. Domest Anim Endocrinol 1997; 14:286-94. [PMID: 9347249 DOI: 10.1016/s0739-7240(97)00025-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Epidermal growth factor (EGF), EGF receptor (EGFR), and basic fibroblast growth factor (bFGF) messenger RNA (mRNA) levels were examined by Northern blot analysis in four tissues (pancreas, liver, kidney, and skeletal muscle) of pig from fetal 90 d to postnatal 180 d of age. The present study shows for the first time that EGF mRNA increased with advancing age in the kidney and skeletal muscle of pig. A high level of EGF mRNA was observed in the kidney compared with the liver and skeletal muscle. In the pancreas, high levels of EGF mRNA were found in fetuses and newborns and were low in older pigs. Pancreatic EGFR mRNA level parallelled its EGF mRNA, whereas in the kidney and skeletal muscle, patterns of EGFR mRNA were reversed to their EGF mRNA levels. In the liver, EGFR mRNA was abundant but EGF mRNA was undetected. In the pancreas and skeletal muscle, the highest levels of bFGF mRNA were found in fetuses of 90 d of age and then decreased with advancing age. In the liver and kidney, there were no major changes in bFGF mRNA levels during the examined developmental periods. These results show that EGF, EGFR, and bFGF mRNA levels are developmentally and tissue specifically regulated in pig. In the pancreas, mRNA levels of EGF, EGFR and bFGF were high in fetal and neonatal life and low thereafter. In the kidney and skeletal muscle, EGF mRNA increased with advancing age. EGF may play a role in muscle growth and maintenance in growing pigs during the later stage of development.
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Millhorn DE, Raymond R, Conforti L, Zhu W, Beitner-Johnson D, Filisko T, Genter MB, Kobayashi S, Peng M. Regulation of gene expression for tyrosine hydroxylase in oxygen sensitive cells by hypoxia. Kidney Int 1997; 51:527-35. [PMID: 9027733 DOI: 10.1038/ki.1997.73] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Carotid body type I cells and the O2 sensitive pheochromocytoma (PC12) cells release dopamine during hypoxia. Reduced O2 tension causes inhibition of an outward rectifying the O2-sensitive potassium (K) channel in the O2-sensitive pheochromocytoma (PC12) cell line, which leads to membrane depolarization and increased intracellular free Ca2+. We found that removal of Ca2+ from the extracellular milieu, inhibition of voltage-dependent Ca2+ channels, and chelation of intracellular Ca2+ prevents full activation of the TH gene expression during hypoxia. These findings suggest that membrane depolarization and regulation of intracellular free Ca2+ are critical signal transduction events that regulate expression of the TH gene in PC12 cells during hypoxia. Gene expression of tyrosine hydroxylase (TH), the rate-limiting enzyme in the biosynthesis of dopamine, is stimulated by reduced O2 tension in both type I cells and PC12 cells. The increase in TH gene expression in PC12 cells during hypoxia is due to increases in both the rate of transcription and mRNA stability. Analysis of reporter-gene constructs revealed that increased transcription of the TH gene during hypoxia is regulated by a region of the proximal promoter that extends from -284 to -150 bases, relative to the transcription start site. This region of the gene contains a number of cis-acting regulatory elements including AP1, AP2 and hypoxia-inducible factor (HIF-1). Competition assays revealed that hypoxia-induced binding occurs at both the AP1 and HIF-1 sites. Results from super-shift and shift Western assays showed that a heterodimer consisting of c-Fos and JunB binds to the AP1 site during hypoxia. Mutagenesis experiments revealed that the AP1 site is required for increased transcription of the TH gene during hypoxia. We also found that the genes that encode the c-Fos and JunB transcription factor proteins are regulated by reduced O2 tension.
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Peng M, LeBel D, Palin MF, Pelletier G. Effect of weaning on epidermal growth factor and its receptor messenger RNA levels in various tissues of piglets. CANADIAN JOURNAL OF ANIMAL SCIENCE 1996. [DOI: 10.4141/cjas96-091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Weights of pancreas, liver, and stomach, and total DNA of pancreas and stomach mucosa per body weight were greater (P < 0.05) in weaned piglets than suckling ones at 30 d of age. There was no effect (P > 0.05) of weaning on epidermal growth factor (EGF) and EGF receptor (EGFR) messenger RNA levels in liver, stomach, duodenum, and skeletal muscle. Messenger RNAs of EGF in pancreas increased following weaning in piglets of 27 (P = 0.0001) and 30 (P = 0.004) d of age, indicating a possible involvement of EGF in pancreatic development during this period. Key words: Weaning, EGF, EGFR mRNA, Pig tissues
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Lai CC, Peng M, Huang L, Huang WH, Chiu TH. Chronic exposure of neonatal cardiac myocytes to hydrogen peroxide enhances the expression of catalase. J Mol Cell Cardiol 1996; 28:1157-63. [PMID: 8762051 DOI: 10.1006/jmcc.1996.0106] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The adaptive response of antioxidant enzymes to oxidative stress in the heart has not been investigated. Because H2O2 is considered to play a major role in reperfusion injury to the heart, this study was undertaken to examine if H2O2 alters the expression of these enzymes in the rat neonatal myocytes. H2O2 was continuously generated by the addition of glucose oxidase to the culture medium. Both the activity and the mRNA for catalase were increased following incubation of neonatal myocytes with non-toxic concentrations of glucose oxidase. The induction of mRNA preceded the enhancement of activity, and both remained elevated after 24 h incubation. Nuclear run-on assay indicated that the transcriptional rate for catalase mRNA was increased. The same treatment did not alter the activities for total superoxide dismutase and Se-glutathione peroxidase. The results suggest that H2O2-induced expression of catalase was in part due to transcriptional activation. It further implies that the induction of catalase may play an important role in protecting hearts from ischemic/reperfusion injury.
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Lainé J, Pelletier G, Grondin G, Peng M, LeBel D. Development of GP-2 and five zymogens in the fetal and young pig: biochemical and immunocytochemical evidence of an atypical zymogen granule composition in the fetus. J Histochem Cytochem 1996; 44:481-99. [PMID: 8627005 DOI: 10.1177/44.5.8627005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
To uncover the mechanisms involved in the biogenesis of secretory granules, we studied development of the exocrine pancreas in the pig from the fetus up to the mature animal by following the enzyme activities and expression (Northern blot) of five zymogens and GP-2, the major protein of the granule membrane. Fetal pancreas mainly contained chymotrypsinogen and barely detectable amounts of amylase, trypsin, lipase, and elastase. GP-2 was not notably expressed before the Day 21 of life. Ultrastructural examination of the fetal tissue embedded in Epon with osmium postfixation or in Lowicryl at -20 degrees C without postfixation showed dense granules with an irregular shape but also showed that most granules had uncondensed contents, with the aspect of immature granules, or had a dense core surrounded by light material. With immunogold cytochemistry, the concentration of chymotrypsinogen was directly associated with the acquisition of electron density by the granule matrix. These observations suggest that fetal granules have a slower rhythm of zymogen condensation and an irregular shape that could be due to the particular composition of the matrix and the absence of GP-2. We conclude that, in the exocrine pancreas, secretory granules can be formed under various conditions, even with a matrix containing a ratio of components very different from that of the normal mature animal.
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Peng M, Huang L, Xie Z, Huang WH, Askari A. Partial inhibition of Na+/K+-ATPase by ouabain induces the Ca2+-dependent expressions of early-response genes in cardiac myocytes. J Biol Chem 1996; 271:10372-8. [PMID: 8626609 DOI: 10.1074/jbc.271.17.10372] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Exposure of neonatal rat cardiac myocytes to ouabain concentrations that caused partial inhibition of Na+/K+-ATPase but no loss of viability, increased c-fos and c-jun mRNAs and the transcription factor AP-1. The increased mRNAs were proportional to the extent of inhibition of Na+/K+-ATPase and the resulting rise in steady state intracellular Ca2+ concentration. The rapid and sustained increase of c-fos mRNA was shown to be due to increased transcriptional rate. Induction of c-fos by ouabain was prevented when either extracellular or intracellular Ca2+ was lowered and was attenuated by pretreatment of myocytes with a phorbol ester under conditions known to down-regulate protein kinase C. Exposure to ouabain for 24-48 h also increased total transcriptional activity and protein content of myocytes. The findings suggest that the same signal responsible for the positive inotropic action of ouabain, i.e. net influx of Ca2+ caused by partial inhibition of Na+/K+-ATPase, also initiates the rapid protein kinase C-dependent inductions of the early-response genes, the subsequent regulations of other cardiac genes by the resulting transcription factors, and stimulation of myocyte growth. Whether these hitherto unrecognized effects of cardiac glycosides are obtained in the intact heart and their relevance to the therapeutic uses of these drugs remain to be determined.
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Karuppayil SM, Peng M, Mendoza L, Levins TA, Szaniszlo PJ. Identification of the conserved coding sequences of three chitin synthase genes in Fonsecaea pedrosoi. JOURNAL OF MEDICAL AND VETERINARY MYCOLOGY : BI-MONTHLY PUBLICATION OF THE INTERNATIONAL SOCIETY FOR HUMAN AND ANIMAL MYCOLOGY 1996; 34:117-25. [PMID: 8732357 DOI: 10.1080/02681219680000181] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Primers having designs based on highly conserved stretches in the deduced amino acid sequences of chitin synthase (CHS) genes were used in PCR reactions to amplify 600 bp and 366 bp products from the genomic DNA of three major causal agents of chromoblastomycosis. Cloning and sequencing of the PCR products of one of these fungi, Fonsecaea pedrosoi, identified three CHS sequences designated as FpCHS1, FpCHS2 and FpCHS3. FpCHS1 and FpCHS2 were homologous to regions of CHS1 and CHS2 of Saccharomyces cerevisiae, and their derived amino acid sequences fell into chitin synthase classes I and II, respectively. FpCHS3 was homologous to a region of the CAL1/CSD2 gene of S. cerevisiae, which codes for the chitin synthase three (Chs3) enzyme in that fungus. Phylogenetic trees constructed using the deduced amino acid sequences of PCR-amplified CHS products from many fungi clustered F. pedrosoi with other dematiaceous fungi, providing new molecular evidence for the genetic relatedness of these organisms. The identification of these CHS genes in F. pedrosoi will facilitate future studies of the functional roles of chitin synthases in the unique in vivo dimorphism exhibited by chromoblastomycotic fungi.
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Peng M, Ma C, Bi S, Wan D, Li X, Li R, Gao Y, Li W. Two passive safety systems in a 200 MW demonstration nuclear heating plant. NUCLEAR ENGINEERING AND DESIGN 1996. [DOI: 10.1016/0029-5493(95)01099-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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130
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Millhorn DE, Conforti L, Beitner-Johnson D, Zhu W, Raymond R, Filisko T, Kobayashi S, Peng M, Genter MB. Regulation of ionic conductances and gene expression by hypoxia in an oxygen sensitive cell line. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1996; 410:135-42. [PMID: 9030290 DOI: 10.1007/978-1-4615-5891-0_20] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We have shown that the PC12 cell line is an excellent model system for investigations of the molecular and cellular processes involved in O2-chemosensitivity. We have identified an O2-sensitive K channel in this cell line that mediates membrane depolarization, an increase in intracellular free Ca2+, and dopamine release during hypoxia. We also presented evidence which shows that expression of the gene for tyrosine hydroxylase, the rate-limiting enzyme in dopamine biosynthesis, is stimulated by reduced O2 tension in PC12 and type I carotid body cells. In addition, we have successfully identified the DNA sequences and trans-acting protein factors that regulate transcription of the TH gene during hypoxia. The mechanisms by which a reduction in O2 tension is transduced into alter cell function including increased gene expression remain unknown. Unpublished results from our laboratory show that the increased TH gene expression during hypoxia does not require activation of the cAMP-PKA signal transduction pathway. We propose that the increase in intracellular free Ca2+ that occurs as a result of membrane depolarization might play an important role. Preliminary findings from our laboratory show that blockade of the voltage operated Ca2+ channel or chelation of intracellular Ca2+ prevent full activation of the TH gene during hypoxia.
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131
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Peng M, Cooper CR, Szaniszlo PJ. Genetic transformation of the pathogenic fungus Wangiella dermatitidis. Appl Microbiol Biotechnol 1995; 44:444-50. [PMID: 8597547 DOI: 10.1007/bf00169942] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Genetic transformation of Wangiella dermatitidis was studied using three plasmid vectors (pAN7-1, pWU44, and pKK5) and both electroporation and polyethyleneglycol-mediated methods. pAN7-1 contains the E. coli hygromycin B (HmB) phosphotransferase (hph) gene. Expression of the hph gene confers resistance to antibiotic HmB. Selection for resistance, indicative of transformation, resulted in 10 203 HmB-resistant colonies/micrograms pAN7-1 on medium containing 100 micrograms HmB/ml. Strains of W. dermatitidis used in this study have innate sensitivity to HmB at a critical inhibitory concentration of 20-40 micrograms/ml. Vectors pWU44 and pKK5 contain a URA5 gene from Podospora anserina. A ura5 auxotroph of W. dermatitidis was transformed to prototrophy with pWU44 or pKK5 by complementation. Transformation frequencies for these two plasmids were between 17-50 transformants/micrograms vector DNA. Southern blotting analysis and polymerase chain reaction detection of DNA from putative transformants confirmed transformation.
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Fan H, Brandt NR, Peng M, Schwartz A, Caswell AH. Binding sites of monoclonal antibodies and dihydropyridine receptor alpha 1 subunit cytoplasmic II-III loop on skeletal muscle triadin fusion peptides. Biochemistry 1995; 34:14893-901. [PMID: 7578101 DOI: 10.1021/bi00045a034] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Triadin binds to the dihydropyridine receptor (DHPr) and the junction foot protein (JFP) in Western blot protein overlay experiments. Fusion peptides were synthesized using an expression system, pGSTag, which includes a protein kinase A phosphorylation site. Expressed peptides are DHPr664-799 encoding rabbit skeletal DHPr alpha1 subunit amino acids 664-799, triadin 1 (1-49), triadin 2 (68-389), triadin 2' (110-389), triadin 2a (68-278), triadin 2a1 (67-163), triadin 2a2 (165-240), triadin 2b (242-389), triadin 2b1 (242-299), triadin 3 (370-706), triadin 3a (370-562), triadin 3b (551-706), triadin 3b1 (551-672), and triadin 3b2 (673-706) (the numbers in parentheses correspond to the amino acid sequence of triadin). The triadin monoclonal antibodies, GE4.90 and AE8.91, bind to intact triadic vesicles as well as to vesicle fragments prepared after treatment with Triton X-100, indicating that they have cytoplasmic epitopes. MAb AE8.91 binds to triadin 2, 2', 2a, and 2a1, while mAb GE4.90 binds to triadin 3, 3b, and 3b2 indicating that residues 110-163 and the C-terminal 34 amino acids contain cytoplasmic domains. Radiolabeled DHPr664-799 binds to triadin in intact vesicles under nonreducing and reducing conditions. It binds to triadin fusion peptides, triadin 2, 2a, 3, 3b, and 3b1, but no to triadin 1 or triadin 3b2. The binding to triadin 2a is the most prominent. Direct binding between DHPr-644-799 and JFP was not seen. These experimental findings indicate that triadin contains an extensive cytoplasmic domain that binds to the domain of DHPr which is considered critical for signal transmission during skeletal muscle excitation-contraction sampling.
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Peng M, Emig FA, Mao A, Lu W, Kirby EP, Niewiarowski S, Kowalska MA. Interaction of echicetin with a high affinity thrombin binding site on platelet glycoprotein GPIb. Thromb Haemost 1995; 74:954-7. [PMID: 8571328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Echicetin, a protein isolated from Echis carinatus snake venom, inhibited platelet aggregation and secretion induced by low concentrations of thrombin ( < 0.2 U/ml), by binding to platelet glycoprotein Ib (GPIb). The inhibition was not observed when the platelets were stimulated with higher concentrations of thrombin ( > 0.2 U/ml). Echicetin competed with thrombin for binding to the high affinity site on GPIb. Thrombin also inhibited 50% of the binding of 125I-echicetin to the platelets.
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Jiang W, Swiggard WJ, Heufler C, Peng M, Mirza A, Steinman RM, Nussenzweig MC. The receptor DEC-205 expressed by dendritic cells and thymic epithelial cells is involved in antigen processing. Nature 1995; 375:151-5. [PMID: 7753172 DOI: 10.1038/375151a0] [Citation(s) in RCA: 671] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Dendritic cells and thymic epithelial cells perform important immunoregulatory functions by presenting antigens in the form of peptides bound to cell-surface major histocompatibility complex (MHC) molecules to T cells. Whereas B cells are known to present specific antigens efficiently through their surface immunoglobins, a comparable mechanism for the capture and efficient presentation of diverse antigens by dendritic cells and thymic epithelial cells has not previously been described. We show here that their antigen-presentation function is associated with the high-level expression of DEC-205, an integral membrane protein homologous to the macrophage mannose receptor and related receptors which are able to bind carbohydrates and mediate endocytosis. DEC-205 is rapidly taken up by means of coated pits and vesicles, and is delivered to a multivesicular endosomal compartment that resembles the MHC class II-containing vesicles implicated in antigen presentation. Rabbit antibodies that bind DEC-205 are presented to reactive T-cell hybridomas 100-fold more efficiently than rabbit antibodies that do not bind DEC-205. Thus DEC-205 is a novel endocytic receptor that can be used by dendritic cells and thymic epithelial cells to direct captured antigens from the extracellular space to a specialized antigen-processing compartment.
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Peng M, Karuppayil SM, Mendoza L, Levins TA, Szaniszlo PJ. Use of the polymerase chain reaction to identify coding sequences for chitin synthase isozymes in Phialophora verrucosa. Curr Genet 1995; 27:517-23. [PMID: 7553935 DOI: 10.1007/bf00314441] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Based on conserved amino-acid regions predicted for the chitin synthases (Chs) of Saccharomyces cerevisiae, two different primer sets were synthesized and used in polymerase chain reactions (PCRs) to amplify 614-bp and 366-bp sequences from genomic DNA of the zoopathogenic fungus Phialophora verrucosa. DNA-sequencing and Southern-blotting analyses of the 614-bp DNA amplification products suggested that portions of two distinct P. verrucosa chitin synthase genes (PvCHS1, PvCHS2), coding for two different zymogenic-type PvChs isozymes, had been identified. The deduced amino-acid sequence of each fell into different Chs classes, namely class I and class II. In addition, the 366-bp DNA segment was shown to code for a conserved region having homology with the CSD2/CAL1 gene of S. cerevisiae, which encodes a nonzymogenic-type enzyme, Chs3, in that fungus. The amino-acid sequence derived from PvCHS3 exhibits 88.2% similarity and 78.4% identity to the same amino-acid region of the S. cerevisiae enzyme. These results provide a critical first step toward investigating the molecular and pathogenic importance of CHS gene regulation in this fungus and for exploring steps leading to Chs function as potential targets for the design of new therapeutic agents.
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136
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Yamaguchi Y, O'Doherty U, Peng M, Steinman RM. Difficulties in obtaining monoclonal antibodies to subsets of human leukocytes, using neonatal tolerance induction in mice. J Immunol Methods 1995; 181:115-24. [PMID: 7730660 DOI: 10.1016/0022-1759(94)00335-t] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Many antigens are shared between different types of human leukocytes. In an effort to obtain new lineage-specific monoclonal antibodies, particularly antibodies to dendritic cells, we attempted to tolerize newborn mice to one type of leukocyte and then immunize the adults with another. We found that T cells, either unstimulated T cells or T blasts, were more effective at inducing neonatal tolerance than non-T cells or B cell lines. However, the tolerance that was achieved was not restricted to T cells, since we could not elicit from the tolerized mice a specific antibody response to a B cell line or to blood dendritic cells. Here we describe several efforts, all unsuccessful, to achieve cell specific immune responses in tolerant mice. The parameters we considered included the type of cell used to tolerize neonatal mice, the regimen of injections for inducing tolerance or eliciting immunity, and the use of several different adjuvants.
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Peng M, Holt JC, Niewiarowski S. Isolation, characterization and amino acid sequence of echicetin beta subunit, a specific inhibitor of von Willebrand factor and thrombin interaction with glycoprotein Ib. Biochem Biophys Res Commun 1994; 205:68-72. [PMID: 7999097 DOI: 10.1006/bbrc.1994.2630] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Echicetin is a dimeric protein isolated from the venom of Echis carinatus that is a potent inhibitor of von Willebrand Factor and thrombin binding to glycoprotein Ib. Here, we report isolation and amino acid sequence of the beta subunit of echicetin that contains 123 amino acids, including 7 cysteines, and shows similarity with amino acid sequences of botrocetin and Factor IXa/Xa binding protein. We provide evidence that biological activity of echicetin which resides in this beta subunit is relatively resistant to reduction of the molecule.
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138
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Peng M, Fan H, Kirley TL, Caswell AH, Schwartz A. Structural diversity of triadin in skeletal muscle and evidence of its existence in heart. FEBS Lett 1994; 348:17-20. [PMID: 8026576 DOI: 10.1016/0014-5793(94)00556-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Triadin has been characterized as an abundant protein co-localized with the calcium release channel on the terminal cisternae of the sarcoplasmic reticulum of the skeletal muscle. Its localization to terminal cisternae of the sarcoplasmic reticulum and functional studies suggest that it has an important role in excitation-contraction coupling. In this study we identify three triadin isoforms in rabbit skeletal muscle and by Northern blot analysis demonstrate that triadin also exists in the heart.
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O'Doherty U, Peng M, Gezelter S, Swiggard WJ, Betjes M, Bhardwaj N, Steinman RM. Human blood contains two subsets of dendritic cells, one immunologically mature and the other immature. Immunology 1994; 82:487-93. [PMID: 7525461 PMCID: PMC1414873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Two subsets of dendritic cells, differing in T-cell stimulatory function, have been purified directly from human blood. Both subsets are positive for major histocompatibility complex (MHC) class II expression and negative for lineage-specific antigens (e.g. CD3, CD14, CD16, CD19 negative), but are separated by exploiting differences in expression of the beta 2-integrin, CD11c. The CD11c-negative subset is functionally immature, requiring monocyte-derived cytokines to develop into typical dendritic cells. The CD11c-positive subset has potent T-cell stimulating activity and expresses the activation antigen CD45RO, unlike its immature counterpart. However, these mature cells only develop typical dendritic morphology and high levels of MHC proteins and adhesins after a period of culture independent of exogenous cytokines. Although the freshly isolated mature dendritic cells resemble monocytes in cytospin preparations, the former lack CD14 and have a much stronger primary T-cell stimulatory capacity. We hypothesize that the CD11c-negative immature cells are marrow-derived precursors to tissue dendritic cells, such as epidermal Langerhans' cells, while the CD11c-positive cells are derived from tissues where they have been activated by antigen, and are en route to the spleen or lymph nodes to stimulate T-cell responses there.
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Bader R, Mannucci PM, Tripodi A, Hirsh J, Keller F, Solleder EM, Hawkins P, Peng M, Pelzer H, Teijidor LM. Multicentric evaluation of a new PT reagent based on recombinant human tissue factor and synthetic phospholipids. Thromb Haemost 1994; 71:292-9. [PMID: 8029792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A new PT reagent based on recombinant human tissue factor and synthetic phospholipids (phosphatidyl choline and phosphatidyl serine) with defined fatty acid side chains was calibrated against BCT/253 and CRM 149R. A small but consistent bias in the International Sensitivity Index (ISI) value was obtained using either the human or rabbit brain reference material. ISI values were around 1.0 or slightly lower depending on the respective instrument. Mixing studies with factor deficient plasmas showed a high factor sensitivity especially for factor VII as compared to commercial rabbit brain or human placenta thromboplastin. In an international field trial the reagent was tested using fully or semi automated Electra coagulometers in 4 different laboratories. Results with normal samples were in excellent agreement among the different laboratories. Mean values were 10.9, 10.9, 11.0, 11.2 s with a range of 9.5 to 12.5 s. Results of males and females were not different. In patients with liver disease very similar PT activities were found as compared to sensitive rabbit brain or human placental thromboplastins. In normals and patients with oral anticoagulation INR values correlated very well against BCT (r = 0.98, regression line y = -0.07 + 0.9 x). The distribution of samples was linear over the whole range. In the comparison against sensitive rabbit brain thromboplastin or human placental thromboplastin similar correlations were found. In a few cases higher INR values were observed for the recombinant reagent especially in patients with intensive treatment. Factor assays in those patients showed at least the strong reduction of one vitamin K-dependent coagulation factor.(ABSTRACT TRUNCATED AT 250 WORDS)
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Dharmavaram RM, Elberson MA, Peng M, Kirson LA, Kelley TE, Jimenez SA. Identification of a mutation in type X collagen in a family with Schmid metaphyseal chondrodysplasia. Hum Mol Genet 1994; 3:507-9. [PMID: 8012364 DOI: 10.1093/hmg/3.3.507] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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Liu M, Peng M, Hu T, Chen M, Lang S. [Pathology of muscle contracture caused by injection and activity of phosphochesterase and insulin receptor]. HUA XI YI KE DA XUE XUE BAO = JOURNAL OF WEST CHINA UNIVERSITY OF MEDICAL SCIENCES = HUAXI YIKE DAXUE XUEBAO 1993; 24:278-280. [PMID: 8288197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The animal model of muscle contracture caused by injection was set up in the experiment. We used the model for excessive healing studies and researched the changes in its pathology, and activity of phosphochesterase and insulin receptor in this model. The experimental results revealed that the pathologic changes belonged to excessive proliferation of connective tissue (excessive healing). When occurred muscle degeneration, infiltration of inflammatory cells, proliferation of fibroblasts and descending of collagen fibers, the activity level phosphochesterase and insulin receptor became higher. The excessive healing occurrence may have something to do with the changes of phosphochesterase and insulin receptor.
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O'Doherty U, Steinman RM, Peng M, Cameron PU, Gezelter S, Kopeloff I, Swiggard WJ, Pope M, Bhardwaj N. Dendritic cells freshly isolated from human blood express CD4 and mature into typical immunostimulatory dendritic cells after culture in monocyte-conditioned medium. J Exp Med 1993; 178:1067-76. [PMID: 8102389 PMCID: PMC2191184 DOI: 10.1084/jem.178.3.1067] [Citation(s) in RCA: 305] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
A procedure has been developed to isolate dendritic cells to a high degree of purity from fresh blood. Prior enrichment methods have relied upon an initial 1-2-d culture period. Purified fresh isolates lack the characteristic morphology, phenotype, and immunostimulatory function of dendritic cells. The purified cells have the appearance of medium sized lymphocytes and express substantial levels of CD4, but lack the T cell molecules CD3, CD8, and T cell receptor. When placed in culture, the cells mature in a manner resembling the previously described, cytokine-dependent maturation of epidermal dendritic cells (Langerhans cells). The cells enlarge and exhibit many cell processes, express much higher levels of major histocompatibility complex class II and a panel of accessory molecules for T cell activation, and become potent stimulators of the mixed leukocyte reaction. Among the many changes during this maturation process are a fall in CD4 and the appearance of high levels of B7/BB1, the costimulator for enhanced interleukin 2 production in T cells. These changes are not associated with cell proliferation, but are dependent upon the addition of monocyte-conditioned medium. We suggest that the freshly isolated CD4-positive blood dendritic cells are recent migrants from the bone marrow, and that subsequent maturation of the lineage occurs in tissues in situ upon appropriate exposure to cytokines.
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Peng M, Lemke PA, Singh NK. A nucleotide sequence involved in replicative transformation of a filamentous fungus. Curr Genet 1993; 24:114-21. [PMID: 8358817 DOI: 10.1007/bf00324674] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Replicative plasmids generated through in-vivo recombination have been identified among transformants of the fungus Pleurotus ostreatus. In addition to sequences from a standard selection vector (pAN7-1), these recombinant plasmids contain recombined sequences of chromosomal origin conferring replicative potential upon the vector. One such recombined sequence, an 1148-bp insert into plasmid pP01, has been characterized. This sequence has been analyzed for secondary structural features as well as for consensus sites affiliated with origins of replication (ori) in other eukaryotic systems. The 1148-bp insert lacks an ORF and does not contain an acceptable match to the commonly identified 11-bp ars consensus sequence (A/TTTTATA/GTTTA/T) for autonomous replication in the yeast Saccharomyces cerevisiae. The analysis, however, revealed a cluster of three hairpin-loop-forming subsequences with individual delta G25 degrees C free energy values of -7.6, -6.4 and -5.2 kcal mol-1. Also found were two 7-bp analogues to centromere-affiliated sequences recognized in other fungi, as well as several putative gyrase recognition sites comparable to the 9-bp S. cerevisiae/E. coli gyrase-binding consensus sequence. Sequences comparable to the ori of the yeast 2-microns plasmid or to various sequences associated with ori of yeast/fungal mitochondrial DNAs (mtDNA) were not present in the 1148-bp insert. Replication of pP01 appears rather to involve a replication of chromosomal derivation devoid of an ars-type consensus.
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Peng M, Lu W, Beviglia L, Niewiarowski S, Kirby EP. Echicetin: a snake venom protein that inhibits binding of von Willebrand factor and alboaggregins to platelet glycoprotein Ib. Blood 1993; 81:2321-8. [PMID: 8481512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Echicetin, a new protein isolated from Echis carinatus venom by reverse phase and ion exchange chromatography specifically inhibited agglutination of fixed platelets induced by several platelet glycoprotein Ib (GPIb) agonists, such as bovine von Willebrand factor (vWF), alboaggregins, and human vWF in the presence of botrocetin. Unlike alboaggregins, echicetin bound to GPIb but did not induce agglutination of washed or fixed platelets. In contrast to disintegrins, it did not block adenosine 5'-diphosphate (ADP)-induced platelet aggregation in the presence of fibrinogen. The apparent molecular weight of echicetin measured on sodium dodecyl sulfate (SDS) gel electrophoresis was 26 Kd under nonreducing conditions. On reduction, echicetin showed 16 and 14-Kd subunits suggesting that the molecule is a dimer. Reduced echicetin retained its binding activity and its inhibitory effect on the agglutination of fixed platelets induced by bovine vWF. 125I-echicetin bound to fixed platelets with high affinity (kd = 30 +/- 1.8 nmol/L) at 45,000 +/- 2,400 binding sites per platelet. The binding was selectively inhibited by a monoclonal antibody to the 45-Kd N-terminal domain of platelet GPIb, but not by monoclonal antibodies to other regions on GPIb. Binding of 125I-bovine vWF to fixed platelets was strongly inhibited by echicetin. In contrast, bovine vWF showed a much weaker inhibitory activity on binding of 125I-echicetin to platelets. The half life of echicetin in blood was approximately 170 minutes with no detectable degradation. Echicetin significantly prolonged the bleeding time of mice, suggesting that it may inhibit vWF binding to GPIb in vivo as well as in vitro.
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Peng M, Lundgren E. Transient expression of the Epstein-Barr virus LMP1 gene in B-cell chronic lymphocytic leukemia cells, T cells, and hematopoietic cell lines: cell-type-independent-induction of CD23, CD21, and ICAM-1. Leukemia 1993; 7:104-12. [PMID: 8093369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The Epstein-Barr virus (EBV) genome has recently been detected in various non-B cell neoplasms, including various T-cell leukemias and in Reed-Sternberg cells of Hodgkin's disease, but the contribution of EBV genes to the transformed phenotype remains unclear. We have investigated the possible effect which the EBV genes LMP1 and EBNA2, of which the expression has been reported in non-B cell neoplasms, may have on a variety of cell types. The LMP1 and EBNA2 genes were transiently expressed from heterologous promoters in two human T-cell lines (HPB-ALL and Jurkat), two human cell lines of the myeloid lineage (K562 and U937), one type I Burkitt's lymphoma cell line (Rael) and in human primary T cells and B-cell chronic lymphocytic leukemia cells. The cell surface expression of CD23, CD21, ICAM-1 and LFA-1 was monitored on transfected cells. In the cell lines, except U937, the surface antigens CD21 and ICAM-1 were upregulated in a dose-dependent and transient manner by the transient expression of LMP1, and EBNA2 slightly enhanced the effects of LMP1 on CD23 and CD21 upregulation. LMP1 also induced increased CD21, ICAM-1 and LFA-1 surface expression on transfected primary T-cells, and CD21 and ICAM-1 in four of five B-cell chronic lymphocytic leukemias tested. Finally, LMP1 transient expression caused increased cell size of the primary T cells and responding B-cell chronic lymphocytic leukemia cells. Our results strongly suggest that LMP1 can trigger specific responses in a variety of white cell types and thus is probably contributing to the phenotype of EBV-positive tumor cells not only in the B-cell lineage.
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MESH Headings
- Antigens, Viral/genetics
- Antigens, Viral/metabolism
- Capsid/genetics
- Capsid/metabolism
- Cell Adhesion Molecules/biosynthesis
- Cell Size
- DNA-Binding Proteins/genetics
- Epstein-Barr Virus Nuclear Antigens
- Gene Expression
- Genes, Viral
- Hematopoietic Stem Cells/microbiology
- Herpesvirus 4, Human/genetics
- Humans
- In Vitro Techniques
- Intercellular Adhesion Molecule-1
- Leukemia, Lymphocytic, Chronic, B-Cell/microbiology
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Receptors, Complement 3d/biosynthesis
- Receptors, IgE/biosynthesis
- T-Lymphocytes/microbiology
- Tumor Cells, Cultured
- Viral Matrix Proteins
- Viral Structural Proteins/genetics
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Peng M, Lundgren E. Transient expression of the Epstein-Barr virus LMP1 gene in human primary B cells induces cellular activation and DNA synthesis. Oncogene 1992; 7:1775-82. [PMID: 1354347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Abstract
The Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) and Epstein-Barr virus nuclear antigen 2 (EBNA2) are expressed in EBV-immortalized human B cells. It has previously been shown that transfection of the LMP1 and EBNA2 genes into Burkitt's lymphoma cell lines results in the up-regulation of CD23, CD21, ICAM-1 and LFA-1 cell-surface proteins. In the present study, the effects of transient expression of the LMP1 and EBNA2 genes were studied in normal primary human B cells pretreated with UV-inactivated EBV particles. To identify and purify cells which express the transfected DNA we used a gene encoding a surface molecule, CD2, as a co-transfection marker. We show that transient expression of the LMP1 gene, from heterologous promoters, is sufficient to induce cellular enlargement and up-regulation of surface expression of the activation markers CD23, CD21, ICAM-1 and LFA-1 in primary B cells. Most importantly, we show that transient expression of the LMP1 gene is sufficient to induce DNA synthesis in human primary B cells. Transient EBNA2 expression enhanced the effect of transient LMP1 expression on CD21 and CD23 cell-surface expression but, under our experimental conditions, inhibited the induction of DNA synthesis by LMP1. We conclude that activation of primary B cells with inactivated EBV particles, followed by transient expression of only two viral genes, EBNA2 and LMP1, is sufficient to reconstitute some of the early events of B-cell immortalization by EBV.
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MESH Headings
- Antigens, Differentiation, T-Lymphocyte/analysis
- Antigens, Viral/analysis
- Antigens, Viral/genetics
- Antigens, Viral/toxicity
- B-Lymphocytes/microbiology
- CD2 Antigens
- DNA/biosynthesis
- Epstein-Barr Virus Nuclear Antigens
- Gene Expression
- Genes, Viral
- Herpesvirus 4, Human/genetics
- Humans
- Lymphocyte Activation
- Phorbol 12,13-Dibutyrate/pharmacology
- Receptors, Immunologic/analysis
- Transcription, Genetic
- Up-Regulation
- Viral Matrix Proteins
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Dharmavaram RM, Peng M, Strawbridge RR, Jimenez SA. Polymerase chain reaction--amplification of the coding sequence of the type X collagen gene from genomic DNA and identification of a polymorphism that changes Gly to Arg at position 545 by single-strand conformation polymorphism analysis. Biochem Biophys Res Commun 1992; 187:420-4. [PMID: 1520329 DOI: 10.1016/s0006-291x(05)81509-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Type X collagen is a specific product of hypertrophic growth plate chondrocytes and it has been suggested that mutations in the corresponding gene (COL1OA1) may be responsible for certain heritable disorders affecting growth plate cartilage such as the epiphyseal dysplasias. We have amplified the coding region of COL1OA1 employing polymerase chain reaction (PCR) of genomic DNA. Single-strand conformation polymorphism (SSCP) analysis of PCR products followed by direct sequencing identified a G to C transition that results in a Gly to Arg substitution at position 545 of the polypeptide chain. The sequence variation was confirmed by restriction enzyme analysis with BsaJ 1. Analysis of a family with multiple epiphyseal dysplasia ruled out this sequence change as a cause of the disease. This is the first report showing application of SSCP for detection of a sequence variant in COL1OA1.
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Peng M, Singh NK, Lemke PA. Recovery of recombinant plasmids from Pleurotus ostreatus transformants. Curr Genet 1992; 22:53-9. [PMID: 1611668 DOI: 10.1007/bf00351742] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A transformation system employing selectable resistance to hygromycin B has been developed for the mushroom-forming fungus, Pleurotus ostreatus. Vector pAN7-1, a commonly used non-replicative vector for integrative transformation in fungi, yielded 5-46 resistant colonies per micrograms of DNA per 10(7) viable protoplasts. Southern blot analysis of certain transformants revealed unexpected replicative plasmids containing pAN7-1 sequences, but modified for size, methylation and restriction enzyme pattern when compared to the initial transforming vector. Two such replicative derivatives of pAN7-1 have been rescued from P. ostreatus by cloning into Escherichia coli. Rescued plasmids have been used to probe DNA from untransformed P. ostreatus in an effort to identify fungal sequences that recombined in vivo with pAN7-1 to form replicative plasmids. Such replicative sequences have been localized in high molecular weight (chromosomal) DNA of wild-type P. ostreatus. Transformation has been obtained for P. ostreatus using a rescued plasmid, thereby confirming the role of this recombinant plasmid as a shuttle vector.
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150
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Peng M, Lu W, Kirby EP. Characterization of three alboaggregins purified from Trimeresurus albolabris venom. Thromb Haemost 1992; 67:702-7. [PMID: 1509413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Alboaggregins (AL-A, AL-B, AL-C) isolated from Trimeresurus albolabris snake venom represent a new family of proteins which bind to platelet glycoprotein Ib (GPIb). These alboaggregins were purified to homogeneity with ion exchange HPLC (Mono-Q column) and hydrophobic HPLC (TSK Phenyl-5PW column). On SDS-polyacrylamide gel electrophoresis, apparent molecular weights of AL-A, AL-B and AL-C were 52 kDa, 26 kDa, and 121 kDa respectively, under nonreducing conditions. Upon reduction, each alboaggregin showed two types of chains with apparent molecular weights in the range of 15-20 kDa. All three alboaggregins agglutinated formalin-fixed platelets. Agglutination activities and binding of labeled alboaggregins to GPIb were specifically inhibited by the monoclonal antibody AK2 which is directed against the 45 kDa N-terminal region on GPIb, but not by monoclonal antibodies against other epitopes on GPIb. 125I-alboaggregin binding to platelets was not altered by the presence of thrombin. Alboaggregins did not bind to GPIIb/IIIa. Alboaggregins were competitive inhibitors for 125I-bovine vWF binding to platelets. Mutual competition studies between AL-A, AL-B and AL-C for the binding of labeled bovine vWF and AL-B to platelets demonstrated that AL-B and AL-C had a significantly higher affinity than AL-A.
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