Search PubMed⌕ Search

Biomedical subjects

Y Hu

Publications and source records attributed to Y Hu.

At least 397 records · Page 22Linked to original sources
PubMed1998

[An analysis on therapeutic effects of excimer laser photorefractive keratectomy for high myopia].

OBJECTIVE: To evaluate the therapeutic effects of 193-nm excimer laser photorefractive keratectomy for the correction of high myopia. METHODS: A Keracor 116 excimer laser and a tapered transition zone technique were used to treat high myopia. It was divided into two groups: the first group -6.00 - 9.75 D, 233 eyes; the second group -10.00 - 14.00 D, 55 eyes. The effect of the tapered transition zone on refraction stability was investigated in a 12-month follow-up study. RESULTS: At one year, of these eyes, 79.4% eyes attained visual acuity of 0.5 or better, 31.6% improved to 1.0 or better, 93.8% of the eyes improved or their best corrected visual acuity did not change, whereas 6.2% lost at least one line. Corneal haze was observed to be severe in one month, and diminished considerably at 6 and 12 months. At one year, no haze could be seen in 87.4%. 52.0% were within +/- 1.00 D and 80.9% in +/- 2.00 D. During one year, 14.9% were complicated with glaucoma because of using steroid drops. CONCLUSION: These data show that excimer PRK for treatment of high myopia is an effective and safe refractive surgery. For severe myopia, it is an effective surgery, but predictability is not satisfactory, and long term follow-up is necessary.

Adolescent↗
PubMed1998

[Determination of chemical constituents of the volatile oil from Curcuma longa by gas chromatography-mass spectrometry].

The study of chemical constituents of the volatile oil from Curcuma longa is reported. The volatile oil was extracted by steam distillation. Fifteen components in the oil were separated and identified by gas chromatography-mass spectrometry(GC/MS). The results were elucidated based on the NBS standard mass spectral data. The total ion current chromatogram showed their mass fraction by normalization method. alpha-curcumene, alpha-zingiberene, 1,8-cineole and zerumbone, which had been reported before were found in Curcuma longa volatile oil, but 1-(3-cyclopentylpropyl)-2,4-dimethylbenzene, beta-sesquiphellandrene, germacrene etc identified simultaneously in the oil had never been reported. The major chemical constituent of the volatile oil from Curcuma longa is alpha-curcumene.

Curcuma↗
PubMed1998

In vitro and in vivo effect of levopraziquantel, dextropraziquantel versus racemic praziquantel on different developmental stages of Schistosoma japonicum.

AIM: To compare the antischistosomal effect of racemic praziquantel (Pra) and its enantiomers, levopraziquantel (L-Pra) and dextropraziquantel (D-Pra), on different developmental stages of Schistosoma japonicum. METHODS: The in vitro effects of the drugs were determined in different stages of schistosomes maintained in RPMI 1640 supplemented with 20% calf serum. In vivo study mice infected with schistosome cercariae were treated intragastrically (ig) with Pra, L-Pra or D-Pra at different intervals after infection. The efficacy of the drugs was evaluated by residual mean worm number. RESULTS: Based on the degree of tegument damage induced by L-Pra, d28 and d35 schistosomes were most susceptible to L-Pra, while d14 schistosomules being least susceptible. At comparable concentrations of 0.1-1 g/ml, L-Pra was more active than Pra even when the concentration of L-Pra was reduced to one-half of the minimum effective concentration of Pra. At above-mentioned concentrations D-Pra exhibited no apparent in vitro effect on different stages of schistosomes. When infected mice were treated ig with L-Pra, Pra or D-Pra at a single dose of 300 mg/kg or 500 mg/kg, only the former two drugs showed apparent effect on d0, d21, d28 and d35 schistosomes and less or much less effect on d3, d7 and d14 schistosomules. D-Pra only exhibited a negligible effect on d35 adult schistosomes as compared with L-Pra and Pra. When mice infected with d35 adult schistosmes were treated ig with L-Pra 150 mg/kg, the efficacy was similar to that of mice treated with Pra 300 mg/kg. CONCLUSION: L-Pra is the principal active component against schistosomes in racemic Pra.

Animals↗
PubMed1998

Pretreatment of donor stimulator cells by 16,16 dimethyl prostaglandin E2 influences the recipient immune response.

BACKGROUND: Immunosuppressive strategies have largely ignored donor-derived stimulatory cells as a target. This study examined whether lipopolysaccharide (LPS) or 16,16 dimethyl prostaglandin E2 (dmPGE2) pretreatment of stimulator cells from B10.BR mice influences effector function of responder T lymphocytes from C3H/HeJ mice in vitro or in vivo. METHODS: B10.BR spleen cells were incubated in vitro in the presence or absence of dmPGE2 or or LPS before the cells were used as stimulators in a mixed lymphocyte culture (MLC) with T cells from C3H/HeJ mice. In parallel studies, B10.BR mice were treated in vivo with dmPGE2 or LPS; spleen cells from these animals were used as stimulators in an MLC and skin was harvested for skin grafts. Cells from untreated or pretreated mice were examined for expression of intercellular adhesion molecule-1 (ICAM-1), B7-1, and B7-2 by fluorescence-activated cell sorter analysis. ICAM-1 mRNA transcripts were determined by reverse transcriptase-polymerase chain reaction. RESULTS: Stimulation of B10.BR-derived spleen cells with LPS before their use as stimulator cells in a MLC resulted in an increase in responder T-cell proliferation compared with use of unstimulated spleen cells (P < 0.05). In contrast, pretreatment of stimulator spleen cells with dmPGE2 resulted in dose-dependent inhibition of the responder T-cell proliferation, with maximum effect seen using a concentration of dmPGE2 of 10(-5) mol/L. The decreased expression of interleukin-1, tumor necrosis factor, leukotriene B4 procoagulant activity, and ICAM-1 by the dmPGE2 pretreated spleen cells correlated with their inefficient in stimulating T-cell proliferation. Spleen cells harvested from B10.BR mice previously injected with dmPGE2 similarly were inefficient as stimulator cells. Skin graft survival was delayed, but not prevented, by in vivo pretreatment of donor mice with dmPGE2. CONCLUSIONS: These data demonstrate the effect of immunomodulation of allogeneic stimulator spleen cells on subsequent responder T-lymphocyte function and allograft survival.

16,16-Dimethylprostaglandin E2↗
PubMed1998

Specific transcription factors prognostic for prostate cancer progression.

We have previously identified (M. Wang et al., Oncol. Res., in press, 1998) an enhancer element [human tissue inhibitor of metalloproteinase-1 enhancer-1 (HTE)] for the human tissue inhibitor of metalloproteinase-1 promoter that binds a novel zinc finger, cysteine-rich transcription factor (CRTF). In this study, we have used electrophoretic mobility shift assays to examine the relative level of expression of CRTF, jun/fos, and IFN-gamma responsive signal transducer activators of transcription (STATs) that bind specific HTE, activator protein, and IFN-gamma (Fcy and interferon regulatory factor) response motifs in tumor lines and human prostate tissue [i.e., normal (n = 3); benign prostatic hyperplasia (BPH; n = 12); high grade prostate intraepithelial neoplasia (PIN; n = 10); and prostate cancer adenocarcinoma (PCA; n = 61) plus seminal vesicle (n = 10) tissues]. The data showed that CRTF was overexpressed in PCA (Gleason's score, 10>8>6>5>4) compared with BPH, PIN, seminal vesicle, and normal tissues. To a much lesser degree, jun/fos and STAT 1 were also elevated in PCA compared to BPH, PIN, and normal tissues. In addition, blinded studies showed that CRTF and jun/fos were present at low levels in organ-confined specimens but at significantly elevated levels (P < 0.001) in samples exhibiting capsular penetration and localized spread, which indicated that CRTF and perhaps jun/fos were markers for cancer progression.

Binding Sites↗
PubMed1998

Host range analysis of simian virus 40, BK virus and chimaeric SV40/BKV: relative expression of large T-antigen and Vp1 in infected and transformed cells.

Simian virus 40 (SV40) persists in Rhesus monkeys and productively infects cultured simian kidney cells. In contrast to the closely related human virus BKV, SV40 is known to propagate inefficiently in human embryonic kidney (HEK) cells and human fibroblasts (HFF). We examined the growth of SV40, BKV and the chimaeric genome virus, SV40/RFV, in several types of human cells. We analysed replication, expression of T-Ag and Vp1 capsid proteins, and cytopathic effects (CPE). We also compared T-Ag and Vp1 expression in infected versus transformed HFF cells. Although SV40 DNA replicated in HFF and in one subtype of HEK cells, viral DNA accumulated slowly and did not reach high levels until six to eight weeks after transfection. In HFF or HEK cells there was little T-Ag produced but Vp1 was produced in significant amounts in HFF cells. In HFF cells the Vp1/T-Ag ratio was approximately 200: 1, and expression of the viral late region appeared to inhibit expression of the T-Ag gene. In contrast, BKV and the SV40/RFV hybrid propagated well in HEK and HFF cells. The Vp1/T-Ag ratios were also high in BKV and SV40/RFV infected HFF cells but more T-Ag was produced with BKV and SV40/RFV Because SV40/RFV contained the RFV capsid genes but a SV40 T-Ag gene and regulatory region, the human versus simian host range of SV40 was controlled by the viral late region, or one or more capsid proteins. This suggested that the production of small amounts of T-Ag could not by itself account for poor growth of SV40 in HFF cells and that very small, barely detectable amounts of T-Ag were sufficient to activate Vp1 gene expression. Also, although some feature of the SV40 late region prevented rapid growth of the virus in HFF cells, poor virus growth could not be explained by the inability to produce a significant amount of Vp1. Although little T-Ag accumulated in SV40 infected HFF and HEK cells, transformants contained large amounts of T-Ag. In transformants there was a reversal of the Vp1/T-Ag ratio, such that T-Ag was now in 10-20 fold greater amount than Vp1. The relatively large amount of T-Ag in transformants could be accounted for by the relative absence of Vp1, which may inhibit T-Ag production, or by integration of the T-Ag gene at a site in the cell DNA which allows for elevated T-Ag gene expression.

Antigens, Polyomavirus Transforming↗
PubMed1998

Identification of positive and negative regulator elements for the tissue inhibitor of metalloproteinase 1 gene.

We have identified an IL-10 inducible enhancer (HTE) (5'-CACGATGACTCATCACTGTTGAAAGACA-3') (-864 to -836 bp) and associated silencer element (HTS) (5'-CCACTGGCCCATCGTATAT-3') (-1284 to -1266 bp) in the 5' promoter region of the human tissue inhibitor of metalloproteinase-1 (TIMP-1) gene. Chloramphenicol acetyl transferase (CAT), electrophoretic migration shift assays (EMSAs), and DNase footprinting revealed that IL-10 (15 ng/ml for 1-2 h) induced the HTE enhancer. In comparison, phorbol ester stimulated the HTS silencer and blocked IL-10's effects in a dose-dependent, orientation- and position-independent fashion, suggesting that HTS is a true silencer element. EMSAs combined with deletion and mutation analysis of the HTE and HTS elements confirmed these observations. Finally, Northern blot, Western blot, immunoprecipitation, and ELISA analysis showed that IL-10 (15 ng/ml) induced TIMP-1 expression (approximately 10-fold by 18 h), whereas PMA (100 ng/ml) inhibited the stimulatory effects of IL-10 on TIMP-1 expression. The data indicate that HTE and HTS function as positive and negative regulatory elements that control human TIMP-1 expression.

Base Sequence↗
PubMed1997

A new symmetrodont mammal from China and its implications for mammalian evolution.

A new symmetrodont mammal has been discovered in the Mesozoic era (Late Jurassic or Early Cretaceous period) of Liaoning Province, China. Archaic therian mammals, including symmetrodonts, are extinct relatives of the living marsupial and placental therians. However, these archaic therians have been mostly documented by fragmentary fossils. This newfossil taxon, represented by a nearly complete postcranial skeleton and a partial skull with dentition, is the best-preserved symmetrodont mammal yet discovered. It provides a new insight into the relationships of the major lineages of mammals and the evolution of the mammalian skeleton. Our analysis suggests that this new taxon represents a part of the early therian radiation before the divergence of living marsupials and placentals; that therians and multituberculates are more closely related to each other than either group is to other mammalian lineages; that archaic therians lacked the more parasagittal posture of the forelimb of most living therian mammals; and that archaic therians, such as symmetrodonts, retained the primitive feature of a finger-like promontorium (possibly with a straight cochlea) of the non-therian mammals. The fully coiled cochlea evolved later in more derived therian mammals, and is therefore convergent to the partially coiled cochlea of monotremes.

Animals↗
PubMed1997

Synergy between L-selectin signaling and chemotactic activation during neutrophil adhesion and transmigration.

L-selectin enables capture and rolling of neutrophils on inflamed endothelium. This may facilitate the binding of agonists such as IL-8 and platelet-activating factor (PAF), which signal CD18-mediated firm adhesion and transmigration. Recent studies demonstrate that L-selectin can mediate transmembrane signaling. However, the functional effects of costimulation through agonist and L-selectin require further study. Here, we quantify cell adhesion, motility, and transmigration in response to co-activation through L-selectin and agonist. The surface expression of CD11b/CD18 increased and L-selectin decreased in proportion to the extent of L-selectin cross-linking. A flow cytometric assay was used to measure CD11b/CD18-dependent adhesion to fluorescent beads adsorbed with albumin. Neutrophil adhesion was detected within seconds of adding PAF (20 pM), IL-8 (50 pM), or cross-linking L-selectin. Costimulation through agonist and L-selectin potentiated by up to threefold the rate and extent of bead capture. Stimulation through L-selectin induced membrane ruffling, whereas PAF or IL-8 induced bipolar shape change. L-selectin cross-linking sustained the transient shape change induced by low concentrations (10-50 pM) of agonist. Chemokinesis stimulated by IL-8 was inhibited in the presence of cross-linking L-selectin. This was attributed to enhanced cell spreading following costimulation. Migration across HUVEC monolayers stimulated with IL-1 was also potentiated in the presence of L-selectin cross-linking. We propose that cross-linking of L-selectin and binding of agonist receptors may act synergistically to amplify neutrophil activation and emigration in the inflamed vasculature.

Cell Adhesion↗
PubMed1997

Fast separations at elevated temperatures on polybutadiene-coated zirconia reversed-phase material.

This paper describes the results of thermal stability studies of polybutadiene-coated zirconia reversed phases and application to fast HPLC separations at elevated temperatures and high flow rates. The thermal stability of the material was evaluated at temperatures up to 200 degrees C, and the rapid analyses of polyaromatic hydrocarbons and typical reversed-phase test mixtures were carried out at 100 degrees C and a flow rate of 5 mL/min. We found that the material is completely stable at 200 degrees C for at least 1300 column volumes. Analysis time can be decreased about 18-fold at high temperatures and flow rates without any significant loss in resolution relative to that at conventional temperatures and normal flow rates. For the separation of a five-component reversed-phase test mixture, the analysis time was only 50 s.

Butadienes↗
PubMed1997

CLARP, a death effector domain-containing protein interacts with caspase-8 and regulates apoptosis.

We have identified and characterized CLARP, a caspase-like apoptosis-regulatory protein. Sequence analysis revealed that human CLARP contains two amino-terminal death effector domains fused to a carboxyl-terminal caspase-like domain. The structure and amino acid sequence of CLARP resemble those of caspase-8, caspase-10, and DCP2, a Drosophila melanogaster protein identified in this study. Unlike caspase-8, caspase-10, and DCP2, however, two important residues predicted to be involved in catalysis were lost in the caspase-like domain of CLARP. Analysis with fluorogenic substrates for caspase activity confirmed that CLARP is catalytically inactive. CLARP was found to interact with caspase-8 but not with FADD/MORT-1, an upstream death effector domain-containing protein of the Fas and tumor necrosis factor receptor 1 signaling pathway. Expression of CLARP induced apoptosis, which was blocked by the viral caspase inhibitor p35, dominant negative mutant caspase-8, and the synthetic caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-(OMe)-fluoromethylketone (zVAD-fmk). Moreover, CLARP augmented the killing ability of caspase-8 and FADD/MORT-1 in mammalian cells. The human clarp gene maps to 2q33. Thus, CLARP represents a regulator of the upstream caspase-8, which may play a role in apoptosis during tissue development and homeostasis.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Nitric oxide induces heat-shock protein 70 expression in vascular smooth muscle cells via activation of heat shock factor 1.

Current data suggest that nitric oxide (NO) is a double-edged sword that could result in relaxation and/or cytotoxicity of vascular smooth muscle cells (SMCs) via cGMP- dependent or -independent signal pathways. Stress or heat shock proteins (hsps) have been shown to be augmented in arterial SMCs during acute hypertension and atherosclerosis, both conditions that are believed to correlate with disturbed NO production. In the present study, we demonstrate that NO generated from sodium nitroprusside (SNP), S-nitroso-N-acetylpenicillamine, and spermine/nitric oxide complex leads to hsp70 induction in cultured SMCs. Western blot analysis demonstrated that hsp70 protein expression peaked between 6 and 12 h after treatment with SNP, and elevated protein levels were preceded by induction of hsp70 mRNA within 3 h. Induction of hsp70 mRNA was associated with the activation of heat shock transcription factor 1 (HSF1), suggesting that the response was regulated at the transcriptional level. HSF1 activation was completely blocked by hemoglobin, dithiothreitol, and cycloheximide, suggesting that the protein damage and nascent polypeptide formation induced by NO may initiate this activation. Furthermore, SMCs pretreated with heat shock (42 degrees C) for 30 min were significantly protected from death induced by NO. Thus, we provide evidence that NO induces hsp70 expression in SMCs via HSF1 activation. Induction of hsp70 could be important in protecting SMCs from injury resulting from NO stimulation.

Animals↗
PubMed1997

Evidence that intramolecular interactions are involved in masking the activation domain of transcriptional activator Leu3p.

The Leu3 protein of Saccharomyces cerevisiae regulates the expression of genes involved in branched chain amino acid biosynthesis and in ammonia assimilation. It is modulated by alpha-isopropylmalate, an intermediate in leucine biosynthesis. In the presence of alpha-isopropylmalate, Leu3p is a transcriptional activator. In the absence of the signal molecule, the activation domain is masked, and Leu3p acts as a repressor. The recent discovery that Leu3p retains its regulatory properties when expressed in mammalian cells (Guo, H., and Kohlhaw, G. B. (1996) FEBS Lett. 390, 191-195) suggests that masking and unmasking of the activation domain occur without the participation of auxiliary proteins. Here we present experimental support for this notion and address the mechanism of masking. We show that modulation of Leu3p is exceedingly sensitive to mutations in the activation domain. An activation domain double mutant (D872N/D874N; designated Leu3-dd) was constructed that has the characteristics of a permanently masked activator. Using separately expressed segments containing either the DNA binding domain-middle region or the activation domain of wild type Leu3p (or Leu3-dd) in a modified yeast two-hybrid system, we provide direct evidence for alpha-isopropylmalate-dependent interaction between these segments. Finally, we use the phenotype of Leu3-dd-containing cells (slow growth in the absence of added leucine) to select for suppressor mutations that map to the middle region of Leu3-dd. The properties of nine such suppressors further support the idea that masking is an intramolecular process and suggest a means for mapping the surface involved in masking.

Amino Acid Sequence↗
PubMed1997

Electrokinetic Behavior of Fluoride Salts as Explained from Water Structure Considerations

Unlike the other silver halides, silver fluoride is positively charged in its saturated solution as determined by nonequilibrium electrophoresis measurements. In the absence of surface hydrolysis reactions, other fluoride salts (LiF, CaF2 , and MgF2 ) also are positively charged in their saturated solutions. Furthermore, the electrokinetic behavior of these fluoride salts is rather insensitive to the fluoride ion activity in neutral or acidic solutions, and reversal of the sign of the surface charge by fluoride addition is not possible. Based on FTIR transmission spectra to describe the water structure of ionic solutions, in situ FTIR/internal reflection spectroscopy (FTIR/IRS) has been used to spectroscopically characterize interfacial water at fluoride salt surfaces. The experimental spectra were examined by consideration of the O-H stretching region (3000-3800 cm-1 ) associated with the vibrational spectra of interfacial water. These results reveal a unique hydration state for fluorides and explain the anomalous electrokinetic behavior of fluoride salts such as LiF, CaF2 , and MgF2 , which show an unexpected insensitivity to the fluoride ion concentration in solution. It appears that this insensitivity is due to the formation of strong hydrogen bonding of the fluoride ions with water molecules. This hydration state prevents the accommodation of excess fluoride ions at surface lattice sites and accounts for the observed electrokinetic behavior.

Journal Article↗
PubMed1997

Discordant activation of stress-activated protein kinases or c-Jun NH2-terminal protein kinases in tissues of heat-stressed mice.

Stress-activated protein kinases (SAPK) or c-Jun NH2-terminal protein kinases (JNK) are believed to be crucial signal transducers between stress stimuli and genetic responses in mammalian cells. These kinases are activated in various types of in vitro cultured cells by heat shock, but a similar activation of SAPK/JNK in tissues in vivo has yet to be shown. In the present study, C57BL/6 mice were exposed to elevated ambient temperature for various time periods, and SAPK/JNK activities determined in protein extracts of brain, heart, liver, spleen, lung, and kidney using protein kinase assay and Western blot analyses. The time course and relative magnitude of the heat-induced SAPK/JNK activity differed among tissues of the same animal. Significant activation of SAPK/JNK was achieved in heart, liver, and kidney at 60 or 90 min of heat stress. This increased activity of SAPK/JNK kinases was demonstrated to result from activation or phosphorylation of existing proteins in tissues. The maximal activation of these kinases showed no direct relationship with the elevation in body temperature (38-40.5 degrees C). Interestingly, SAPK/JNK activation did not occur in lung, brain, or spleen of the same heat-stressed mouse. Although elevated body temperature (40.5 degrees C) did not result in SAPK/JNK activation in spleen and lung tissues, heat stress induced SAPK/JNK activation in cultured organs or fibroblasts derived from spleen or lung of C57BL/6 mice. Furthermore, activity and amount of SAPK/JNK proteins were the most abundant in brain among tissues examined. Thus, our findings demonstrated that heat shock-induced SAPK/JNK activation in vivo lacks much of the characteristic coordinate control of activation of cultured cell lines, and suggests that the mechanisms controlling SAPK/JNK activation are influenced by physiologic factors that cannot be studied in vitro.

Animals↗
PubMed1997

Submillisecond protein folding kinetics studied by ultrarapid mixing.

An ultrarapid-mixing continuous-flow method has been developed to study submillisecond folding of chemically denatured proteins. Turbulent flow created by pumping solutions through a small gap dilutes the denaturant in tens of microseconds. We have used this method to study cytochrome c folding kinetics in the previously inaccessible time range 80 micros to 3 ms. To eliminate the heme-ligand exchange chemistry that complicates and slows the folding kinetics by trapping misfolded structures, measurements were made with the imidazole complex. Fluorescence quenching due to excitation energy transfer from the tryptophan to the heme was used to monitor the distance between these groups. The fluorescence decrease is biphasic. There is an unresolved process with tau < 50 micros, followed by a slower, exponential process with tau = 600 micros at the lowest denaturant concentration (0.2 M guanidine hydrochloride). These kinetics are interpreted as a barrier-free, partial collapse to the new equilibrium unfolded state at the lower denaturant concentration, followed by slower crossing of a free energy barrier separating the unfolded and folded states. The results raise several fundamental issues concerning the dynamics of collapse and barrier crossings in protein folding.

Animals↗
PubMed1997

Identification of p53 unbound to T-antigen in human cells transformed by simian virus 40 T-antigen.

In several clones of SV40-transformed human cells, we investigated the relative amounts of large T-Antigen (T-Ag) and p53 proteins, both unbound and associated within complexes, with the goal of identifying changes associated with transformation and immortalization. Cells were transformed by wild type (wt) T-Ag, a functionally temperature sensitive T-Ag (tsA58) and other T-Ag variants. Western analysis showed that while most of the T-Ag was ultimately bound by p53, most of the p53 remained unbound to T-Ag. Unbound p53 remained in the supernatant after a T-Ag immunoprecipitation and p53 was present in two to fourfold excess of T-Ag. In one transformant there was five to tenfold more p53 than T-Ag. p53 was present in transformants in amounts at least 200-fold greater than in untransformed human cells. In wt and variant T-Ag transformants, including those generated with tsA58 T-Ag, large amounts of unbound p53 were present in both pre-crisis and immortal cells and when the cells were grown at permissive or non-permissive temperatures. We also found that in transformants produced by tsA58, an SV40/JCV chimeric T-Ag and other variants, T-Ag appeared to form a complex with p53 slowly perhaps because one or both proteins matured slowly. The presence in transformed human cells of large amounts of unbound p53 and in excess of T-Ag suggests that sequestration of p53 by T-Ag, resulting from complex formation, is required neither for morphological transformation nor immortalization of human cells. Rather, these results support the proposal that high levels of p53, the T-Ag/p53 complexes, or other biochemical event(s), lead to transformation and immortalization of human cells by T-Ag.

Antigens, Polyomavirus Transforming↗