Scanning optical microscopy with an electrogenerated chemiluminescent light source at a nanometer tip

Electrogenerated chemiluminescence at electrodes with effective diameters down to 155 nm was used as a stable light source for near-field scanning optical microscopy imaging of an interdigitated array and a submicrometer size test substrate. Light was generated in a thin (approximately 500 microm) layer of an aqueous solution of 15 mM Ru(bpy)3(2+) and 100 mM tri-n-propylamine in a pH 7.5 buffer. The resolution obtained was compared to that found with a micrometer size electrode. The shear force from the tip attached to a quartz tuning fork was used to monitor and control the tip-to-substrate separation within the near field regime.

Size-dependent control of the binding of biotinylated proteins to streptavidin using a polymer shield

Many medical and biotechnological processes rely on controlling and manipulating the molecular-recognition capabilities of proteins. This can be achieved using small molecules capable of competing for protein binding or by changing environmental parameters that affect protein structure and hence binding. An alternative is provided by stimuli-responsive polymers that change reversibly from a water-soluble expanded coil to a water-insoluble collapsed globule upon small changes in temperature, pH or light intensity: when attached to proteins in the vicinity of their binding sites, they reversibly block and release small ligands. Here we show how this approach can be extended to achieve size-selective binding of large, macromolecular ligands. We use the thermally responsive polymer poly(N,N-diethylacrylamide) (PDEAAm), and attach it to the protein streptavidin approximately 20 A from the binding site for biotinylated proteins. Below the lower critical solution temperature of PDEAAm, the polymer is in its extended state and acts as a 'shield' to block the binding of large biotinylated proteins; above this temperature, it collapses and exposes the binding site, thereby allowing binding. We find that the degree of shielding depends on both the size of the biotinylated protein and the size of PDEAAm, suggesting that 'smart' polymer shields could be tailored to achieve a wide range of size-dependent ligand discrimination for use in affinity separations, biosensors and diagnostics technologies.

Effects of clenbuterol on insulin resistance in conscious obese Zucker rats

The present study was conducted to determine the effect of chronic administration of the long-acting beta(2)-adrenergic agonist clenbuterol on rats that are genetically prone to insulin resistance and impaired glucose tolerance. Obese Zucker rats (fa/fa) were given 1 mg/kg of clenbuterol by oral intubation daily for 5 wk. Controls received an equivalent volume of water according to the same schedule. At the end of the treatment, rats were catheterized for euglycemic-hyperinsulinemic (15 mU insulin. kg(-1). min(-1)) clamping. Clenbuterol did not change body weight compared with the control group but caused a redistribution of body weight: leg muscle weights increased, and abdominal fat weight decreased. The glucose infusion rate needed to maintain euglycemia and the rate of glucose disappearance were greater in the clenbuterol-treated rats. Furthermore, plasma insulin levels were decreased, and the rate of glucose uptake into hindlimb muscles and abdominal fat was increased in the clenbuterol-treated rats. This increased rate of glucose uptake was accompanied by a parallel increase in the rate of glycogen synthesis. The increase in muscle glucose uptake could not be ascribed to an increase in the glucose transport protein GLUT-4 in clenbuterol-treated rats. We conclude that chronic clenbuterol treatment reduces the insulin resistance of the obese Zucker rat by increasing insulin-stimulated muscle and adipose tissue glucose uptake. The improvements noted may be related to the repartitioning of body weight between tissues.

[Relationship between atmospheric temperature and growth characteristics of main edible grapes in south China]

The study shows that there existed a significant relationship between the new branch growth of grapes and temperature, especially effective accumulate temperature. Kyoho had the fastest new branch growth rate among all varieties, which was 0.43433 cm in length with raising 10 degrees C while effective accumulate temperature was over 190.68 degrees C. Mixiangbao had the slowest new branch growth rate, which was 0.17150 cm in length with raising 10 degrees C while effective accumulate temperature was over 367.19 degrees C. The economic properties and quality in variety character were researched by fuzzy valuation. The results showed that Kyoho, Jingya, Fujiminori, Mixiangbao, and Longbao were worthy of spreading, while Zizhenxiang would be limited in production, and Wase takasumi and Heifeng should be eliminated through selection.

Optical, magnetic, and electronic properties of peripherally fused macrocycles: molybdocene porphyrazines

Metal-free and copper porphyrazines, [H(2)pz] and [Cu pz], have been fused at the periphery with molybdocene dithiolene, [Cp(2)Mo]. The optical, magnetic, and electronic properties of the resulting neutral and cationic complexes are studied, using first-principles density functional theory implemented by the discrete variational method. Analysis of the charge and spin distribution shows that the porphyrazine core is strongly coupled with the peripheral complex. The calculated optical absorption is found to be in reasonable agreement with experimental spectra, lending support to our theoretical model. Under appropriate circumstances one observes interaction of unpaired spins localized in the vicinity of both metal sites. The calculated spin distribution shows that [Cp(2)Mo][Cu pz] and [Cp(2)Mo][H(2)pz](+) have a magnetic moment of 1 micro(B) while [Cp(2)Mo][Cu pz](+) and [Cp(2)Mo][H(2)pz] have no moment, in good agreement with the results of X-band EPR spectra. The Cu-Mo magnetic interaction is antiferromagnetic, being mediated by pyrrol nitrogens, meso nitrogens, carbons, and sulfurs.

Chemokines stimulate human T lymphocyte transendothelial migration to utilize VLA-4 in addition to LFA-1

Lymphocyte infiltration in inflammation is induced by the dual actions of chemokines and cell adhesion molecules. The role of LFA-1 and VLA-4 in chemokine-induced T cell transendothelial migration (TEM) across cytokine-activated endothelium has not been examined. LFA-1, but not VLA-4, mediated blood T cell TEM to RANTES, macrophage inflammatory protein-1alpha (MIP-1alpha), and stromal cell-derived factor-1 (SDF-1), and across tumor necrosis factor alpha (TNF-alpha) or interferon-gamma (IFN-gamma) -stimulated endothelial cells (EC). Chemokine stimulation in combination with TNF-alpha activation of EC induced TEM, which was partially mediated by VLA-4. SDF-1 increased a beta1-integrin activation epitope on T cells and enhanced VLA-4-mediated adhesion. Thus, LFA-1 mediates TEM under most conditions, but VLA-4 can also mediate TEM, although, in contrast to LFA-1, this requires exogenous chemokines and EC activation. In addition, an LFA-1- and VLA-4-independent pathway of lymphocyte TEM can also be induced by SDF-1.

Mechanistic investigation of smart polymer-protein conjugates

Many affinity separation and diagnostic applications rely upon both capture and release steps. There is thus a need for methods to enhance the reversibility of biomolecular interactions. We have previously demonstrated that stimuli-responsive polymers can be used to gate biomolecular reactions when conjugated near the active site of proteins. Here we have used a new smart polymer, N,N-dimethyl acrylamide-co-4-phenylazophenylacrylate that has allowed a mechanistic investigation of the smart polymer switches. This polymer was conjugated via a vinyl sulfone terminus to cysteine residues of genetically engineered streptavidin mutant E116C, where the polymer is conjugated close to the biotin-binding site, and streptavidin mutant S139C, where the conjugation site is distant. The biotin binding switching activity was strongly dependent on conjugation position, as the E116C conjugate displayed a large thermal response while the S139C conjugate displayed only small effects. Kinetic measurements of biotin release demonstrated that the off-rate of biotin was unperturbed and that the thermally triggered release of biotin with the E116C conjugate was due to the blocking the reassociation of biotin. The addition of free polymer to purified E116C conjugates was also shown to increase the blocking and release properties of the switch. This effect was site dependent, suggesting that the conjugated polymers were directing a physical aggregation near the binding site that effectively enhanced the switching activity. These investigations provide mechanistic insight that can be utilized to design better molecular switches for a variety of stimuli-responsive polymer-protein conjugates.

Early and mid-term angiographic and clinical results after intracoronary duet stent placement

The Duet stent (Guidant/Advanced Cardiovascular Systems) is a new stent with a corrugated ring design and very limited data on its short- and mid-term performance. Accordingly, in this study we sought to determine the early and mid-term clinical and angiographic outcomes in a moderate-sized series of 86 consecutive patients who underwent placement of 108 premounted Duet stents in 98 coronary lesions. Procedural success, accomplished in all patients, was accompanied by a significant reduction in lesion severity from 89% +/- 11% before to 5% +/- 3% diameter stenosis after the procedure (P = 0.0001) and a 0.9% incidence of subacute stent thrombosis. Angiographic restudy at 5.7 months in 89% of eligible patients revealed a binary in-stent restenosis rate of 26%. Coronary stenting with the new Duet stent confers a low risk of stent thrombosis and a favorable mid-term clinical and angiographic outcome despite the presence of a large proportion of patients at high risk of in-stent restenosis.

[Some biological characteristics of genetically engineered insecticidal Pseudomonas fluorescens]

Plasmid stability, Antifungal activity, plant-colonizing ability, UV resistance and inseticidal activity in field were analysed for the engineered Pseudomonas fluorescens (Pf) strain IPP202. The results indicated that the recombinant plasmid in IPP202 was very stable after successive diluting culturing and after continuous culturing, There was no significant change in the properties beneficial to plants, such as antifungal activity and plant-colonizing ability as compared with the original strain P303. IPP202 was much more resistant to UV than Bt strain HD73. The control effect in field against cotton boll worm in field was close to that of a locally used Bt-chemical mixture in normal applied concentration. All the data indicated that the engineered Pf strain was a one with prosperous future after further study.

[A study of phenylketonuria heterozygotes screening in married population of Tianjin area]

OBJECTIVE

To find out a method that is simple and reliable for screening phenylketonuria(PKU) heterozygotes.

METHODS

Detecting and analyzing plasma phenylalanine(Phe) and tyrosine(Tyr) from 101 known-PKU heterozygotes and 2023 married people by means of a high performance liquid chromatograph.

RESULTS

Significant differences were observed between known- PKU heterozygotes and screening population in plasma Phe, Phe/Tyr and Phe(2)/Tyr. The values of plasma Phe, Phe/Tyr and Phe(2)/ Tyr from 94.1% known-PKU heterozygotes were higher than mean+2s of those values from screening population. According to the limits of mean+2s, 81 cases were screened out from the 2023 married people. It was the first time to get the actual heterozygote frequency of 4% from population.

CONCLUSION

The biochemical method mentioned above is available for use in screening PKU heterozygotes.

Founder's Award, Society for Biomaterials. Sixth World Biomaterials Congress 2000, Kamuela, HI,May 15-20, 2000. Really smart bioconjugates of smart polymers and receptor proteins

Over the past 18 years we have been deeply involved with the synthesis and applications of stimuli-responsive polymer systems, especially polymer-biomolecule conjugates. This article summarizes our work with one of these conjugate systems, specifically polymer-protein conjugates. We include conjugates prepared by random polymer conjugation to lysine amino groups, and also those prepared by site-specific conjugation of the polymer to specific amino acid sites that are genetically engineered into the known amino acid sequence of the protein. We describe the preparation and properties of thermally sensitive random conjugates to enzymes and several affinity recognition proteins. We have also prepared site-specific conjugates to streptavidin with temperature-sensitive polymers, pH-sensitive polymers, and light-sensitive polymers. The preparation of these conjugates and their many fascinating applications are reviewed in this article.

A Kinetic Study on Photocatalytic Oxidation of Phenol in Water by Silica-Dispersed Titania Nanoparticles

Photocatalytic oxidation of phenol in water was carried out with nanoparticles of silica-titania mixtures, which were synthesized under different temperatures and silica-to-titania ratios. The crystal size of TiO(2) (in anatase phase) was determined to be in the nanometer range and it increased with increasing autoclaving temperature. Furthermore, there was no obvious relationship between the ize and the SiO(2)/TiO(2) ratio at the same preparation temperature. A specific reaction rate constant (k(s)) was used for comparison of photocatalytic activity of different samples. It was found that k(s) decreases with increasing anatase size and TiO(2) concentration. A kinetic model was developed to describe the effect of the crystal size and titania concentration on the reactivity of the SiO(2)-TiO(2) samples. Copyright 2000 Academic Press.

[Expression and synergism of two cry insecticidal protein genes in Pseudomonas fluorescens]

Several engineered Pseudomonas fluorescens(Pf) strains were constructed mainly based on a Pseudomonas plasmid pJMS6 alpha-lac and two insecticidal crystal protein genes of Bacillus thuringiensis, cry1Ac and cry2Aa, and the host Pf strain, P303, which was with highly antifungal activity to some plant disease fungi and colonizing ability on a wide range of plants. The DNA introduction was confirmed by PCR-RFLP and Southern blot. The 132 kD insecticidal protein was detected in IPP101 and IPP202 by SDS-PAGE and rhombic insecticidal protein crystals of them were observed through electron microscope, also indicating that cry1Ac gene was highly expressed. The results of insecticidal bioassay indicated that IPP101 was more toxic than IPP201, and IPP202 was the most toxic among the 3 strains. LC50 to the neonates of cotton boll worm(Helicoverpa armigera) were 0.02604, 0.00812 and 0.00186 mL/g feed, consecutively. In IPP202, two gene products showed significant synergism, with the co-toxicity coefficient of 332.8.

[Expression of inducible nitric oxide synthase in human esophageal biopsies from carcinoma and precancerous lesions]

OBJECTIVE

To investigate the possible role of inducible nitric oxide synthase (iNOS) in esophageal carcinogenesis.

METHODS

iNOS expressions in normal epithelial cells(NC), hyperplastic cells(HC), atypical hyperplastic cells(AHC) from grade I to III, carcinoma in situ(CIS), squamous cell carcinoma(SCC), and adenocarcinoma(ADC) were detected with immunohistochemistry.

RESULTS

The positive rates of immunohistochemistry staining was 0 for NC, 2.5% for HC, 4.0%, 7.5% and 2.5% for AHC grade I to III respectively, 1.4% for CIS, 8.5% for SCC and 71.4% for ADC.

CONCLUSIONS

There is a high expression of iNOS in human esophageal adenocarcinomas. Frequent expression of iNOS may be a potential event in ADC carcinogenesis. There is no correlation between iNOS and SCC carcinogenesis.

Quantification of 3-D coronary arterial motion using clinical biplane cineangiograms

Speculation that the motion of the coronary arteries might be involved in the pathogenesis of coronary atherosclerosis has generated growing interest in the study of this motion. Accordingly, a system has been developed to quantify 3-D coronary arterial motion using clinical biplane cineangiograms. Exploiting the temporal continuity of sequential angiographic images, a template matching technique is designed to track the non-uniform frame-to-frame motion of coronary arteries without assuming that the vessels experience uniform axial strain. The implementation of the system is automated by a coarse-to-fine matching process, thus improving the efficiency and objectivity of motion analysis. The system has been validated and employed to characterize the in vivo motion dynamics of human coronary arteries; illustrative results show that this system is a promising tool for routine clinical and laboratory analysis of coronary arterial motion.

Dynamics of human coronary arterial motion and its potential role in coronary atherogenesis

Mechanical forces have been widely recognized to play an important role in the pathogenesis of atherosclerosis. Since coronary arterial motion modulates both vessel wall mechanics and fluid dynamics, it is hypothesized that certain motion patterns might be atherogenic by generating adverse wall mechanical forces or fluid dynamic environments. To characterize the dynamics of coronary arterial motion and explore its implications in atherogenesis, a system was developed to track the motion of coronary arteries in vivo, and employed to quantify the dynamics of four right coronary arteries (RCA) and eight left anterior descending (LAD) coronary arteries. The analysis shows that: (a) The motion parameters vary among individuals, with coefficients of variation ranging from 0.25 to 0.59 for axially and temporally averaged values of the parameters; (b) the motion parameters of individual vessels vary widely along the vessel axis, with coefficients of variation as high as 2.28; (c) the LAD exhibits a greater axial variability in torsion, a measure of curve "helicity," than the RCA; (d) in comparison with the RCA, the LAD experiences less displacement (p = 0.009), but higher torsion (p = 0.03). These results suggest that: (i) the variability of certain motion parameters, particularly those that exhibit large axial variations, might be related to variations in susceptibility to atherosclerosis among different individuals and vascular regions; and (ii) differences in motion parameters between the RCA and LAD might relate to differences in their susceptibility to atherosclerosis.

Human papillomavirus type 16-immortalized endocervical cells selected for resistance to cisplatin are malignantly transformed and have a multidrug resistance phenotype

Cis-diamminedichloroplatinum (II) (cisplatin, CDDP) is a highly effective chemotherapeutic agent against cervical cancer, but drug resistance is a major obstacle in its clinical application. The mechanism of drug resistance in human cervical cancer is not well understood. Here, we established an in vitro endocervical, cisplatin-resistant cell system that mimics the development of cisplatin resistance in the human cervix. Human papillomavirus (HPV) type 16-immortalized human endocervical cells (HEN-16-2) were treated with cisplatin, and the cisplatin-selected cells (HEN-16-2/CDDP) were resistant to cisplatin, paclitaxel, actinomycin D, doxorubicin, etoposide, and 5-fluorouracil, thus demonstrating a multidrug resistance (MDR) phenotype. Furthermore, compared with a similar passage of drug-sensitive HEN-16-2 cells, HEN-16-2/CDDP cells exhibited the general growth characteristics of cancer cell lines: faster growth in medium containing serum and high calcium levels, higher saturation density, anchorage-independent growth, and formation of tumors in nude mice. These results provided the first in vitro evidence that cisplatin selection can transform HPV-immortalized endocervical cells and cause a phenotype of MDR.

[Study on ascite of ovarian cancer]

OBJECTIVE

Analysis of correlative factors in ascite of ovarian cancer.

METHODS

The clinical data of 72 patients with ovarian cancer admitted to our hospital from 1993 to 1998 were analyzed retrospectively.

RESULTS

73.5% of patients with ovarian cancer had cancer cells in ascite, the incidence of ascite was 81.9%, III and IV stage ovarian cancer with cancer cells in ascite were 91.2%, positive rate of tumor cells obviously increased in cases whose ascite were more than 1,000 ml, in cases with tumor surface infiltration as well as with metastasis to omentum, intestine and diaphragm. CA125 value in ascite without cancer cells was (324.94 +/- 527.64) kU/L, whereas in ascite with cancer cells it was (5,172.64 +/- 1,432.61) kU/L. Whether cancer cells were positive or negative. Chromosomal aneuploidy was detected in two third of the cases.

CONCLUSION

Routine examination of cancer cells, chromosome and CA125 in ascite with ovarian cancer may improve the diagnostic accuracy.

Sulfatide binding and activation of leukocytes through an L-selectin-independent pathway

Sulfatide has been reported to activate leukocytes through L-selectin. Here we provide evidence that sulfatide binds to and activates leukocytes through both L-selectin-dependent and -independent pathways. Rat leukocytes of various sources shed surface L-selectin after phorbol myristate acetate (PMA) treatment, however, these cells retained the ability to bind sulfatide. In addition, sulfatide also bound to an L-selectin-negative cell line EL-4, and the binding was up-regulated by PMA. Sulfatide induced aggregation of L-selectin-positive lymphocytes, which was highly dependent on divalent cations, protein tyrosine kinases (PTK), and protein kinase C (PKC), but was independent of beta1 and beta2 integrins. In contrast, sulfatide-induced EL-4 cell aggregation required an LFA-1/ICAM-1 adhesion pathway but not PTK and PKC. A sulfatide receptor of 65 kDa was isolated from EL-4 cells. Taken together, this study suggests that sulfatide can bind to and activate leukocytes through an L-selectin-independent molecule and triggers signal transduction pathways different from those induced by L-selectin activation.

Regulation of chemokine-induced transendothelial migration of T lymphocytes by endothelial activation: differential effects on naive and memory T cells

Human T lymphocyte transendothelial migration (TEM) was examined in response to chemokines across cytokine-activated endothelium. Monocyte chemotactic protein-1 (MCP-1), RANTES, and macrophage inflammatory protein-1alpha (MIP-1alpha) induced TEM by memory T cells, while stromal cell-derived factor-1 (SDF-1) induced TEM by both naive and memory T cells. Tumor necrosis factor alpha (TNF-alpha) and interleukin-1 (IL-1) increased endothelial adhesion molecule (CAM) expression, whereas interferon-gamma (IFN-gamma) induced little up-regulation of CAM. However, both TNF-alpha and IFN-gamma strongly facilitated T cell migration, which was completely inhibited by pertussis toxin and both greatly increased TEM to RANTES, MIP-1alpha, and SDF-1 selectively of memory but not naive T cells. Thus, the dual selective effect on memory T cells of endothelial activation and these chemokines promotes the preferential recruitment of memory T cells to inflammatory sites. However, the enhanced chemokine-induced migration by memory T cells across activated endothelium appears to be independent of the increase in endothelial CAM expression. G-protein-linked stimuli may play an important part in T cell TEM across cytokine-activated endothelium.

BAG-1 promotes apoptosis induced by N-(4-hydroxyphenyl)retinamide in human cervical carcinoma cells

N-(4-hydroxyphenyl)retinamide (4-HPR) is a synthetic apoptosis-inducing retinoid with cancer chemopreventive properties and lower toxicity than all-trans retinoic acid. BAG-1 is an antiapoptotic gene that is overexpressed in cervical and other cancers. In this study, we examined whether BAG-1 can inhibit 4-HPR-induced apoptosis in the C33A cervical carcinoma cell line. Surprisingly, although it inhibited apoptosis induced by five different apoptotic stimuli, overexpression of BAG-1 enhanced apoptosis induced by 4-HPR, producing a 2.5-fold lower IC(50) of 4-HPR. The effects of BAG-1 on 4-HPR-induced apoptosis were mediated by enhancing the caspase-3 activation pathway. Deletion mutation experiments showed that the central ubiquitin homology domain of BAG-1 protein was necessary for its promotion of 4-HPR-induced apoptosis, whereas its C-terminal Hsp70/Hsc70-interacting domain was required for its inhibition of staurosporine-induced apoptosis. These in vitro results suggest that the effectiveness of 4-HPR against the development of malignancy may be due to the overexpression of BAG-1 in cancer cells.

Microscopic view of a two-dimensional lattice-Gas ising system within the grand canonical ensemble

A reversible 2D critical transition is observed on the GaAs(001) surface and modeled as a lattice-gas Ising system. Without depositing any material, 2D GaAs islands spontaneously form. The order parameter, four critical exponents, and coupling energies are measured from scanning tunneling microscope images of the microscopic domain structure and correlation functions as a function of temperature and pressure. Unprecedented insight into the domain structure of a 2D Ising system through the critical point and a complete Hamiltonian for modeling the GaAs(001) surface are presented.

Jones matrix formalism for quasioptical EPR

The Jones matrix formalism that has been used to analyze quasioptical millimeter-wave circuits is extended for specific application to high-frequency electron paramagnetic resonance (EPR). A survey of general expressions for Jones matrices of elements commonly used in quasioptical EPR spectrometers is given. The Jones matrix representations of quasioptical transmission and reflection cavities are derived, and their relationship to the equivalent circuit and transmission line representations used for conventional EPR cavities is demonstrated. The formalism is applied to selected quasioptical EPR spectrometer designs and experimental tests of the formalism are presented for two configurations of a quasioptical spectrometer operating at 220 GHz.

Two new cyclic peptides from Drymaria diandra

Two new cyclic peptides, drymarins A and B, were isolated from the whole plants of Drymaria diandra B1. Their structures were determined by detailed spectroscopic analysis as cyclo(-Phe1-Pro1-Pro2-Pro3-Phe2-Phe3-Val-Ile-Ala-) and cyclo (-Pro1-Phe-Tyr-Pro2-Gly-Leu-).

Resistance to apoptosis is correlated with the reduced caspase-3 activation and enhanced expression of antiapoptotic proteins in human cervical multidrug-resistant cells

Recent studies have indicated that induction of apoptosis is the primary cytotoxic mechanism of most cancer chemotherapeutic agents, and abnormalities in the control of apoptosis can affect the sensitivity of malignant cells to multiple drugs. Here, we treated cells with cisplatin and other apoptotic stimuli and found that multidrug-resistant (MDR) endocervical HEN-16-2/CDDP cells, compared with drug-sensitive parental cells, were significantly more resistant to apoptosis and exhibited decreased proteolytic activation of caspase-3. The latter was further demonstrated by decreased cleavage of its substrate poly(ADP-ribose) polymerase (PARP). Further, Western blot analysis showed that MDR HEN-16-2/CDDP cells had significantly higher levels of the apoptosis-inhibiting proteins BAG-1 p50 and p33 isoforms and Bcl-X(L). This study provided the first evidence that overexpression of antiapoptotic BAG-1 p50 and p33 and Bcl-X(L) may cause resistance to apoptosis through reduction of caspase-3 activity in human cervical cells having an MDR phenotype.

Flow cytometric DNA analyses of epithelial dysplasia of the esophagus

OBJECTIVE

To investigate, with flow cytometry, DNA aneuploidy as a marker of early carcinogenesis in dysplastic esophageal lesions.

STUDY DESIGN

DNA content of exfoliated cells from 789 cases of esophageal dysplasia (including mild dysplasia, 195 cases; moderate dysplasia, 383 cases; and severe dysplasia, 211 cases) was determined with a FACS 420 flow cytometer.

RESULTS

Cellular DNA content was closely related to the severity of dysplasia. The carcinogenesis rate in patients with dysplasia showed that DNA aneuploidy was significantly higher than in patients showing DNA diploidy.

CONCLUSION

DNA aneuploidy in dysplastic lesions is a very important early signal of carcinogenesis. Patients with dysplastic lesions showing DNA aneuploidy should be treated and closely followed.

Site-specific polymer-streptavidin bioconjugate for pH-controlled binding and triggered release of biotin

Low molecular weight copolymers of acrylic acid (AAc) and N-isopropylacrylamide (NIPAAm) have been synthesized with reactive OH groups at one end, using a chain transfer polymerization technique. The copolymer displays both pH and temperature sensitivity over a wide and useful range of pHs and temperatures, which permits both pH and temperature control of polymer conformation. This copolymer has been conjugated to a specific cysteine thiol site inserted by genetic engineering near the recognition site of streptavidin (SAv). In this paper, we demonstrate that this bioconjugate can provide pH control of biotin binding to and triggered release from the mutant SAv. These actions are relevant to affinity separations, biosensors, diagnostics, enzyme processes, and targeted delivery of drugs or chemical agents, labels, and other signals.

Cloning of Chinese obese cDNA and its expression in E. coli

OBJECTIVE

To obtain the sequence of Chinese obese (OB) cDNA and establish a method of leptin production in China.

METHODS

Han Chinese OB cDNA fragment was obtained by reverse transcriptase-polymerase chain reaction (RT-PCR) with total RNA extracted from human adipocytes and was inserted into the expressing vector pBV220. Then the constructed recombinant plasmid pBV220-OB was transformed to E. coli DH5 alpha for leptin expression. The recombinant expressing system was confirmed by restriction endonuclease digestion, DNA sequencing and protein expression. E. coli cells were lysed by high-pressure homogenization. After cell membrane was extracted, the inclusion bodies were mainly renatured and purified primarily by precipitation with ammonium sulfate and gel chromatography through a Sephadex G75 column. The activity of recombinant leptin was determined by its influence on the satiety and weight gain of mice.

RESULTS

Analysis of DNA sequence showed that Han Chinese OB cDNA included the glutamine codon at 49. The amount of recombinant leptin expressed in E. coli accounted for 31%-47% of total cellular proteins. From 1 L of fermentative bacteria about 40 mg of pure recombinant human leptin was isolated with a purity of being above 95%. The recombinant human leptin could reduce food intake and inhibit weight gains in mice.

CONCLUSION

The glutamine codon at 49 is not missing in Chinese OB gene. The biologically active human leptin can be obtained by a relatively simple method of recombinant DNA technology.

Smart and biofunctional streptavidin

The high affinity recognition of biotin and biotinylated molecules has made streptavidin one of the most important components in diagnostics and laboratory kits. While it is extremely useful as the native protein, there are many applications where its function can be improved re-engineering the subunits. We review here our efforts to construct streptavidin tetramers that have 'smart' recognition capabilities, and which display functional peptide sequences. These smart and biofunctional streptavidin derivatives can 'talk' to cells, and 'listen' to external signals which control capture and release of biotinylated molecules.

Effect of tumor necrosis factor-alpha and interleukin-2 on spleen lymphocyte migration in mouse skin

Tumor necrosis factor-alpha (TNF-alpha) and interleukin-2 (IL-2) are reported to enhance lymphocyte binding to endothelial cells in vitro. We examined these two agents on lymphocyte migration in vivo. Spleen lymphocytes were radiolabeled with tritiated uridine (3H-UR) and then injected i.v. into mice. Each cytokine (TNF-alpha or IL-2) or both cytokines were then injected intradermally on the back of mice. The results demonstrated that TNF-alpha stimulates lymphocyte migration in vivo in dose-dependent fashion. Kinetic analysis demonstrated that migration with TNF-alpha started at 3 h, peaked at 6 h, followed by a gradual decline back to baseline at 24 h. IL-2, on the other hand, was nearly inactive, and did not augment lymphocyte migration over and above that induced by TNF-alpha when both cytokines were injected together.

Effect of carbohydrate supplementation on postexercise GLUT-4 protein expression in skeletal muscle

The effect of carbohydrate supplementation on skeletal muscle glucose transporter GLUT-4 protein expression was studied in fast-twitch red and white gastrocnemius muscle of Sprague-Dawley rats before and after glycogen depletion by swimming. Exercise significantly reduced fast-twitch red muscle glycogen by 50%. During a 16-h exercise recovery period, muscle glycogen returned to control levels (25.0 +/- 1.4 micromol/g) in exercise-fasted rats (24.2 +/- 0. 3 micro). However, when carbohydrate supplementation was provided during and immediately postexercise by intubation, muscle glycogen increased 77% above control (44.4 +/- 2.1 micromol/g). Exercise-fasting resulted in an 80% increase in fast-twitch red muscle GLUT-4 mRNA but only a 43% increase in GLUT-4 protein concentration. Conversely, exercise plus carbohydrate supplementation elevated fast-twitch red muscle GLUT-4 protein concentration by 88% above control, whereas GLUT-4 mRNA was increased by only 40%. Neither a 16-h fast nor carbohydrate supplementation had an effect on fast-twitch red muscle GLUT-4 protein concentration or on GLUT-4 mRNA in sedentary rats, although carbohydrate supplementation increased muscle glycogen concentration by 40% (35.0 +/- 0.9 micromol/g). GLUT-4 protein in fast-twitch white muscle followed a pattern similar to fast-twitch red muscle. These results indicate that carbohydrate supplementation, provided with exercise, will enhance GLUT-4 protein expression by increasing translational efficiency. Conversely, postexercise fasting appears to upregulate GLUT-4 mRNA, possibly to amplify GLUT-4 protein expression on an increase in glucose availability. These regulatory mechanisms may help control muscle glucose uptake in accordance with glucose availability and protect against postexercise hypoglycemia.

[Prediction of the outcome of dysplasia of esophageal epithelium by high resolution image analysis]

OBJECTIVE

To predict the outcome of dysplasia of esophageal epithelium by means of high resolution image analysis(HRIA).

METHODS

Asymptomatic adults were examined for balloon cytology of the esophagus in 1983 from Heshun Commune of Linxian County. Ninety three cases of severe dysplasia and 122 cases of mild dysplasia of the esophagus were selected for this study. By means of an Axiomat-microscope equipped with TV-camera, 100 normal nuclei of well-preserved cells in the intermediate layer of Pap-stained squamous epithelium were randomly examined.

RESULTS

Of the 93 cytologically diagnosed severe dysplasia cases, 24, 14 and 7 progressed to carcinoma in 3, 5 and 9 years, respectively. In the other 48 cases, dysplasia remained stable or regressed to normal. The other cases were used as the control. According to chromatin features, correct diagnosis of cases was achieved by HRIA in 75.0%(18/24), 85.7%(12/14) and 85.7%(6/7) of the cases examined, respectively (P < 0.001). Of the 122 cytologically diagnosed mild dysplasia, 16, 13 and 12 cases progressed to carcinoma in 3, 5 and 9 years, respectively. The other 81 cases remained stable or regressed to normal. Correct diagnosis was made by HRIA in 93.8%(15/16), 76.9%(10/13) and 83.3%(10/12) of the cases examined, respectively (P < 0.001).

CONCLUSION

Chromatin nuclear features examined by HRIA can predict the outcome of precancerous lesions and discriminate progressor from non-progressor ones. It can be used as surrogate endpoint biomarkers for the evaluation of efficacy of chemoprevention trial.

Thermoprecipitation of streptavidin via oligonucleotide-mediated self-assembly with poly(N-isopropylacrylamide)

A versatile strategy has been developed for selectively and sequentially isolating targets in a liquid-phase affinity separation environment. The strategy uses a recently developed approach for joining together molecules in linkages that are defined by the complementary pairing of oligonucleotides conjugated to the different molecules [Niemeyer, C. M., Sano, T., Smith, C. L., and Cantor, C. R. (1994) Nucleic Acids Res. 22, 5530-9]. In the work presented here, streptavidin was noncovalently coupled with the temperature-responsive poly(N-isopropylacrylamide) [poly(NIPAAM)] through the sequence-specific hybridization of oligonucleotides conjugated to the protein and polymer. A 20-mer oligonucleotide was covalently linked through a heterobifunctional linker to a genetically engineered streptavidin variant that contained a unique cysteine residue at the solvent-accessible site Glu 116. The complementary DNA sequence was conjugated to the end of a linear ester-activated poly(NIPAAM). The two conjugates were allowed to self-assemble in solution via hybridization of their complementary DNA sequences. The streptavidin-poly(NIPAAM) complex could be used to affinity-precipitate radiolabeled biotin or biotinylated alkaline phosphatase above 32 degrees C through the thermally induced phase separation activity of the poly(NIPAAM). The streptavidin-oligo species could then be reversibly separated from the precipitated polymer-oligo conjugate and recycled by lowering the salt concentration, which results in denaturation of the short double-stranded DNA connection. The use of oligonucleotides to couple polymer to streptavidin allows for selective precipitation of different polymers and streptavidin complexes based on the sequence-specific hybridization of their oligonucleotide appendages.

Interaction between gene p53 and oncogene mdm2 in human glandular lung cancer cell line GLC-82

OBJECTIVE

To study the interaction between oncogene mdm2 and wp53 in human glandular lung cancer cell line GLC-82.

METHODS

By lipofectamine-mediated DNA transfection, wp53 and mdm2 were transfected separately or co-transfected into GLC-82 cells via retrovival vector pDOR-neo, a carrier of wp53 and mdm2.

RESULTS

The growth of GLC-82 cells was blocked and their DNA synthesis inhibited by wp53, its colony-forming rate in soft agar culture and the tumorigenicity in nude mice declined and mdm2 antagonized the function of wp53.

CONCLUSION

After the recombinant vector pDOR-mdm2 was transfected into GLC-82 cells containing wp53, mdm2 partially deprives wp53 of its function of inhibiting the growth of GLC-82 cells.

Disruption of myoglobin in mice induces multiple compensatory mechanisms

Myoglobin may serve a variety of functions in muscular oxygen supply, such as O(2) storage, facilitated O(2) diffusion, and myoglobin-mediated oxidative phosphorylation. We studied the functional consequences of a myoglobin deficiency on cardiac function by producing myoglobin-knockout (myo(-/-)) mice. To genetically inactivate the myoglobin gene, exon 2 encoding the heme binding site was deleted in embryonic stem cells via homologous recombination. Myo(-/-) mice are viable, fertile, and without any obvious signs of functional limitations. Hemoglobin concentrations were significantly elevated in myo(-/-) mice. Cardiac function and energetics were analyzed in isolated perfused hearts under resting conditions and during beta-adrenergic stimulation with dobutamine. Myo(-/-) hearts showed no alteration in contractile parameters either under basal conditions or after maximal beta-adrenergic stimulation (200 nM dobutamine). Tissue levels of ATP, phosphocreatine ((31)P-NMR), and myocardial O(2) consumption were not altered. However, coronary flow [6.4 +/- 1.3 ml.min(-1).g(-1) [wild-type (WT)] vs. 8.5 +/- 2.4 ml.min(-1).g(-1) [myo(-/-)] [and coronary reserve [17.1 +/- 2.1 (WT) vs. 20.8 +/- 1.1 (myo(-/-) ml. min(-1).g(-1) were significantly elevated in myo(-/-) hearts. Histological examination revealed that capillary density also was increased in myo(-/-) hearts [3,111 +/- 400 mm(-2) (WT) vs. 4,140 +/- 140 mm(-2) (Myo(-/-)]. These data demonstrate that disruption of myoglobin results in the activation of multiple compensatory mechanisms that steepen the pO(2) gradient and reduce the diffusion path length for O(2) between capillary and the mitochondria; this suggests that myoglobin normally is important for the delivery of oxygen.

[Detecting microorganisms in soil by PCR and molecular hybridization]

PCR and molecular hybridization provide new methods to detect microorganisms in environment. A simple, sensitive protocol was developed to detect Bacillus thuringiensis HD-1 in soil by PCR and Southern Blotting in this study. Methods of extracting DNA from soil and purification were compared. By a modified total DNA extraction from soil and purification, followed by PCR and Southern Blotting, strain HD-1 released into soil can be detected with a sensitivity of 2.2 x 10(2) cells/g soil. By using other specific primers, this detection protocol can be widely used in the research of ecology and risk assessment of genetically engineered microorganisms released into environment.

A novel flavonoid glycoside from Drymaria diandra

A novel flavonoid glycoside, drymariatin A, was isolated from the whole plants of Drymaria diandra (Caryophyllaceae). By spectroscopic analysis, its structure was elucidated as 6-trans-[2''- O-(alpha-rhamnopyranosyl)]-ethenyl-5,7,4'-trihydroxy-flavone.

[Long-term effect of treating patients with precancerous lesions of the esophagus]

OBJECTIVE

To report long term therapeutic effect in patients with esophageal pre-cancerous lesions in high-risk area of esophageal cancer.

METHODS

The therapeutic trial enrolled 2,531 cases of severe dysplasia and 3,393 cases of mild dysplasia. A 2-arm randomized, placebo-controlled design was used in which the participants received Zeng Sheng Ping (ZSP, an herbal composite), retinamide or placebo for cases with severe dysplasia and riboflavin or placebo for those with mild dysplasia.

RESULTS

Treatment with ZSP and retinamide decreased malignant transformation rate of severe dysplasia by 52.2% and 43.2%, respectively after 5 years of treatment. When the treatment had been discontinued for 4 years, the rate of malignat transformation was decreased by 42.1% and 38.2% respectively, which remained significantly higher than that of the placebo-treated control. Riboflavin treatment was continued for 9 years. At the end of 5-year medication, the malignant transformation rate decreased by 34.8%, which was not significantly different from that of the placebo control. When the treatment was continued up to 9 years, the rate was further decreased to 37.0%, which became statistically significant.

CONCLUSION

ZSP, retinamide and riboflavin treatment can effectively prevent esophageal dysplasia from transforming into carcinoma.

Differential expression of antiapoptotic gene BAG-1 in human breast normal and cancer cell lines and tissues

BAG-1 is an antiapoptotic protein that binds to and enhances the antiapoptotic activity of Bcl-2. It binds several growth factor and hormone receptors and modulates their function. BAG-1 was also shown recently to be expressed as four protein isoforms, p50, p46, p33, and p29, through alternative translation initiation. Although many apoptosis-associated genes have been linked to oncogenesis of human breast cancer, the role of BAG-1 has not been fully elucidated. In this study, we examined the expression of BAG-1 RNA or protein isoforms and its interacting antiapoptotic proteins, Bcl-2 and BcI-X(L), in breast normal and tumor cell lines and tissues by Northern or Western blot analysis. We provide convincing evidence that both BAG-1 RNA and protein are overexpressed in human breast cancer cell lines. More importantly, we found that the expression of two isoforms of BAG-1, p46 and p33, was also much higher in breast primary tumors. The expression of Bcl-2 and Bcl-X(L) correlated with that of BAG-1 in breast normal and carcinoma cell lines but not tissues. Our study suggests that BAG-1 isoforms may serve as a molecular marker, independent of Bcl-2 and Bcl-X(L), for human breast cancer.

Temperature control of biotin binding and release with A streptavidin-poly(N-isopropylacrylamide) site-specific conjugate

The many laboratory and diagnostic applications utilizing streptavidin as a molecular adaptor rely on its high affinity and essentially irreversible interaction with biotin. However, there are many situations where recovery of the biotinylated molecules is desirable. We have previously shown that poly(N-isopropylacrylamide) (PNIPAAm), a temperature-sensitive polymer, can reversibly block biotin association as the polymer's conformation changes at its lower critical solution temperature (LCST). Here, we have constructed a streptavidin-PNIPAAm conjugate which is able to bind biotin at room temperature or lower and release bound biotin at 37 degrees C. The conjugate can repeatedly bind and release biotin as temperature is cycled through the LCST. A genetically engineered streptavidin mutant, E116C, which has only one cysteine residue, was conjugated site specifically via the sulfhydryl groups with a PNIPAAm that has pendent sulfhydryl-reactive vinyl sulfone groups. The conjugation site is near the tryptophan 120 residue, which forms a van der Waals contact with biotin that is important in generating the large binding free energy. The temperature-induced conformational change of the polymer at position 116 may lead to structural changes in the region of tryptophan 120 that are responsible for the reversible binding between biotin and the conjugated streptavidin.

Effects of Curcuma Longa on proliferation of cultured bovine smooth muscle cells and on expression of low density lipoprotein receptor in cells

OBJECTIVE

To investigate the inhibitory effects of aqueous turmeric extract (AqT) and serum of rats orally treated with ethanol extract of turmeric (SeT) on proliferation of vascular smooth muscle cells (VSMC) and its effects on the expression of low density lipoprotein receptor (LDL-R) antigen on the surface of smooth muscle cells.

METHODS

Enzyme-linked immunosorbent assay (ELISA) for the expression of LDL-R protein and thiazolyl blue (MTT) assay for the proliferation of VSMC were used in this study.

RESULTS

Both aqueous turmeric extract (AqT) and serum of rats orally treated with ethanol extract of turmeric (SeT) could inhibit 10% serum activated proliferation of VSMC. The inhibition shown in both experiments was dose-dependent with an inhibitory rate of 18.9% at 20 mg/ml AqT and rate of 20.1% at 10% SeT respectively. AqT up-regulated the expression of LDL-R protein with a highest rate at 5 mg/ml AqT in 3% lipoprotein deficient serum (LPDS). SeT did not show significant effect on the expression of LDL-R on the surface of VSMC.

CONCLUSION

The extracts of turmeric may be extended to decrease the risk of atherosclerosis (AS).

Method for measuring in vivo oxygen transport rates in a bioartificial organ

Oxygen transport is crucial for the proper functioning of a bioartificial organ. In many cases, the immunoisolation membrane used to protect the transplanted cells from the host's immune system can be a significant barrier to oxygen transport. A method is described for measuring the in vitro and in vivo oxygen transport characteristics of a planar immunoisolation membrane. The in vitro oxygen permeability of the membrane was found to equal 9.22 x 10(-4) cm/sec and was essentially the same as the in vivo value of 9.51 x 10(-4) cm/sec. The fact that the in vitro and in vivo membrane permeabilities are identical indicates that any fibrotic tissue adjacent to the immunoisolation membrane did not present a significant resistance to the transport of oxygen. The measured oxygen permeability was also found consistent with the solute permeabilities obtained in a previous study for larger molecules. Based on the oxygen permeability results, theoretical calculations for this particular membrane indicate that about 1,100 islets of Langerhans/cm2 of membrane area can be sustained at high tissue densities and only 660 islets/cm2 can be supported at low tissue densities.

Attenuating the decline in ATP arrests the exercise training-induced increases in muscle GLUT4 protein and citrate synthase activity

Thirty-two female Sprague-Dawley rats were assigned to one of four groups: control (CON); exercise training (TR); exercise training + clenbuterol treatment (0.8 mg kg body wt(-1) d(-1)) (TR + CL) or exercise training + clenbuterol treatment + 2% beta-guanidinoproprionic acid diet (TR + CL + beta) to examine whether alterations in the high energy phosphate state of the muscle mediates exercise training-induced increases in skeletal muscle GLUT4 protein concentration and citrate synthase activity. Exercise training consisted of running the rats 5 d week(-1) for 8 weeks on a motor-driven treadmill (32 m min(-1), 15% grade). Gastrocnemius GLUT4 protein concentration and citrate synthase activity were significantly elevated in the TR animals, but these adaptations were attenuated in the TR + CL animals. Providing beta-GPA in combination with clenbuterol enabled training to elevate GLUT4 protein concentration and citrate synthase activity, with the increase in GLUT4 being greater than that observed for the TR animals. Skeletal muscle ATP levels were reduced in the TR + CL + beta animals while ATP levels in the TR + CL animals were significantly elevated compared with CON. An acute 40-min bout of electrical stimulation of the sciatic nerve was found to lower skeletal muscle ATP levels by approximately 50% and elevate cAMP levels in all groups. No difference in post-contraction cAMP levels were observed among groups. However, post-contraction ATP levels in the TR + CL animals were significantly greater than the other groups. Collectively, these findings suggest that exercise training-induced increases in skeletal muscle GLUT4 protein concentration and citrate synthase activity are initiated in response to a reduction in the skeletal muscle ATP concentration.

Photocatalytic Properties of Titania Pillared Clays by Different Drying Methods

Photocatalysts based on titania pillared clays (TiO2 PILCs) have been prepared through a sol-gel method. Different drying methods, air drying (AD), air drying after ethanol extraction (EAD), and supercritical drying (SCD) have been employed and found to have significant effects on the photocatalytic efficiency of the resultant catalysts for the oxidation of phenol in water. Titania pillared clay (TiO2 PILC) obtained by SCD has the highest external and micropore surface area, largest amount and smallest crystallite size of anatase, and exhibited the highest photocatalytic activity. Furthermore, silica titania pillared clay (SiO2-TiO2 PILC) after SCD, titania coated TiO2 PILC (SCD) and SiO2-TiO2 PILC (SCD) were synthesized to study the key factors controlling the photocatalytic activity. It is concluded that the dispersion of nanometer-sized anatase on the surface of the PILC particles and the suspensibility of the particles are the most important factors for high photocatalytic efficiency. Copyright 1999 Academic Press.

Computer-assisted design and manufacture of posterior full crowns

OBJECTIVE

To build an experimental system for the computer-assisted design (CAD) of full crowns and to obtain data for computer-assisted manufacturing (CAM) of full crowns.

MATERIALS AND METHODS

Three steps are involved in building the system: measuring the prepared tooth, the adjacent mesial and distal teeth, and the opposing teeth by means of digital speckle correlation; reconstructing the shape of the measured teeth; and developing CAD for full crowns. The standard shape of the corresponding tooth was modified to fit the defective tooth on the basis of buccolingual and occlusal-gingival distance as well as the occlusal relationship of the defective tooth.

RESULTS

CAD for full crowns was developed and was obtained for CAM of posterior full crowns.

CONCLUSIONS

The CAD method for full crowns is convenient and economical and can be used for anterior and posterior crown design, copying, and veneer.

[Surgical treatment of aortopulmonary septal defect]

OBJECTIVE

To study the surgical treatment of aortopulmonary septal defect.

METHOD

From January 1983 to December 1996, 5 patients with aortopulmonary septal defect (APSD) (2 male and 3 female) aged from 6 to 34 years (mean 17.4 years) underwent surgical treatment. According to Mori's were classification, 5 patients belonged to type I, 2 type II and 1 type III. The diameters of the defect ranged from 1.0 to 3.0 cm. The operations were performed under moderate hypothermic cardiopulmonary bypass. Pulmonary artery incision was performed, in 3 patients while aortic incision in the other 2. All defects were repaired by Dacron patch.

RESULT

There were no operative deaths and postoperative complications. During follow-up of 10 months to 12 years, no late complications and deaths were found.

CONCLUSION

The operation should be done early as possible whenever the diagnosis is established. The surgical repair should be taken under cardiopulmonary bypass. To chose an incision on the aorta is more reasonable than on the pulmonary artery. The use the dacron patch can prevent stenosis and recanalization after operation.

Variability of the planarity of the human aortic bifurcation

The susceptibility of vascular branches to atherosclerosis is believed to be due in part to the unusual fluid dynamic environments that the vessel wall experiences in these regions. As vascular geometry is a primary determinant of the local haemodynamic environment, it is of interest to quantitate the geometric features of vascular branches and their variability. The present research focusses on branch planarity, using axial magnetic resonance images of the aortic bifurcations of 20 healthy subjects. The in vivo images were processed to obtain vector representations of the vessel axes at the bifurcation, from which the planarity of the bifurcation was derived using a novel robust definition. Three-dimensional reconstructions of the bifurcations were rendered using computer graphics techniques to demonstrate the variability of the planarity of this region of the vasculature; this variability might be related to variable predispositions to atherosclerosis at the aortic bifurcation.

Oxidative and malondialdehyde modification of low-density lipoprotein: a comparative study of binding and degradation by macrophages and endothelial cells

Comparative study of oxidatively modified low-density lipoprotein (Ox-LDL) and malondialdehyde-modified low-density lipoprotein (MDA-LDL) is important for further understanding the biological properties of Ox-LDL, such as its toxic effects, immunogenicity and multiplicity of scavenger receptor binding. In this study, the characteristics of Ox-LDL and MDA-LDL binding and degradation were compared. The results show that when their degree of modification (as determined by relative electrophoretic mobility) was similar, the binding and degradation of Ox-LDL by the macrophage cell line P388D1 were greater than those of MDA-LDL. The binding and degradation of Ox-LDL by macrophages and human umbilical vein endothelial cells increased with the degree of modification. In addition, Ox-LDL or MDA-LDL could competitively inhibit binding of labelled Ox-LDL or labelled MDA-LDL to their respective macrophage receptors, and could partially inhibit each other.