Biomedical subjects

Jun Cheng

Publications and source records attributed to Jun Cheng.

At least 73 records · Page 4Linked to original sources

PubMed2005

[Effects of bFGF on the nasal mucosa after endoscopic sinus surgery].

OBJECTIVE: To explore the effect of bFGF on nasal mucosa after ESS. METHOD: Ten cases of type I phase 3 chronic sinusitis were selected randomly. For each patient bFGF was intranasally used in one single nasal cavity a week after ESS. The other cavity, treated with nothing, was used as control. Scanning electron microscopy examinations of middle meatus mucosa were made 1,1. 5, 2 and 3 month after ESS. RESULT: In the first month after operation ciliated cells in the mucosa swelled and lined unregularly, the cilia exfoliated. From the sixth week to the 2nd month ciliated cells lined more regularly and the number of cells as well as the density of cilia increased obviously but the cilia aligned in disturbance. In the 3rd month after ESS, the swell of mucosa subside completely and cilia of columnar epithelial cells moved in one direction,which meant the cilia recover the function. CONCLUSION: bFGF can speed up the recovery of nasal mucosa both in number and in function after ESS.

Adolescent↗

PubMed2005

[Screening and cloning of hepatitis C virus non-structural protein 4A interacting protein gene in hepatocytes].

OBJECTIVE: To investigate biological functions of hepatitis C virus (HCV) non-structural protein 4A (NS4A). METHODS: Yeast-two hybrid technique was performed to seek proteins in hepatocytes interacting with HCV NS4A. HCV NS4A bait plasmid was constructed by ligating the NS4A gene with carrier plasmid pGBKT7, then it was transformed into yeast AH109 (alpha type). The transformed yeast cells were amplified and mated with yeast cells Y187 (alpha type) containing liver cDNA library plasmid pACT2 in 2 x YPDA medium. Diploid yeast cells were plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) and synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing X-alpha-gal for selection two times. After extracting plasmid from blue colonies, plasmid DNA was transformed into competent E.coli and analyzed by DNA sequencing and bioinformatics methods. RESULTS: Among twenty-two positive colonies there were eleven positive for metallothionein 2A, three for eukaryotic translation elongation factor 1 alpha 1, two for albumin, two for RNA binding motif protein 21, two for myomesin, one for cytochrome C oxidase II, and one for ATPase. CONCLUSIONS: Genes of HCV NS4A interacting proteins in hepatocytes were successfully cloned and the results pave the way for studying the biological functions of NS4A and associated proteins.

Carrier Proteins↗

PubMed2005

[A study of the down-regulation effect of hepatitis B virus pre-protein S2 on inducible nitric oxide synthase gene promoter].

OBJECTIVES: To investigate the regulating effect of HBV pre-S2 protein on iNOS gene promoter and the molecular biological mechanisms of pre-S2 protein in HBV pathogenicity. METHODS: Polymerase chain reaction (PCR) technique was employed to amplify the sequence of iNOS promoter and 3 deletion mutants using HepG2 genomic DNA as the template, and the products were cloned into the pGEM-T vector. The iNOS gene and 3 deletion mutants were cut from T- iNOS by Kpn I and Xho I, and then cloned into pCAT3-Basic. The resulting vectors were named p1-iNOSp, p2-iNOSp, p3-iNOSp, and p4-iNOSp. Each of the reporter vectors was transfected into the HepG2 cell line and cotransfected into HepG2 cells with pcDNA3.1(-)-pre-S2 by FuGENE 6 transfection reagents. The HepG2 cells transfected with pCAT3-Basic were used as a negative control. The activity of CAT in HepG2 cells transfected was detected by an ELISA kit 48 hours after the transfection, which reflected the regulating effect of HBV pre-S2 protein on iNOS gene promoter activity. RESULTS: The expressive vector pcDNA3.1(-)-pre-S2 and report vector pCAT3-iNOSp were constructed and confirmed by restriction enzyme digestion and sequencing. The expression of pcDNA3.1(-)-pre-S2 in HepG2 cells could down-regulate the activity of p1-iNOSp, p3-iNOSp, and the inhibition rate was 54.7% and 79.5%, respectively. The expression of pcDNA3.1(-)-pre-S2 in HepG2 cells had no regulatory effects on p2-iNOSp and p4-iNOSp. CONCLUSION: It is suggested that HBV pre-S2 protein can down-regulate iNOS gene promoter.

Down-Regulation↗

PubMed2005

[Screening and cloning of hepatitis C virus non-structural protein 4B interacting protein gene in hepatocytes].

OBJECTIVE: To investigate biological functions of non-structural protein 4B (NS4B) of hepatitis C virus (HCV), yeast-two hybrid technique was performed to seek proteins in hepatocytes interacting with HCV NS4B. METHODS: HCV NS4B bait plasmid was constructed by ligating the NS4B gene with carrier plasmid pGBKT7 and transformed into yeast cells AH109 (type alpha). The transformed yeast cells were amplified and mated with yeast cells Y187 (alpha type) containing liver cDNA library plasmid pACT2 in 2 x YPDA medium. Diploid yeast cells were plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) and synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing x-alpha-gal for selecting two times. After extracting plasmid from blue colonies, plasmid DNA was transformed into competent Escherichia coli and analysed by DNA sequencing and bioinformatics. RESULTS: Five genes in eight positive colonies were obtained. There were one NADH dehydrogenase subunit 3, one cytochrome c oxidase subunit III, one retinol binding protein 4, one reticulon 3-A (RTN3) and one fibrinogen gamma polypeptide (FGG). CONCLUSION: Genes of HCV NS4B interacting proteins in hepatocytes were successfully cloned and the results paved the way for studying the biological functions of NS4B and associated proteins.

Blotting, Western↗

PubMed2005

[Relations between serum homocysteine and folic acid levels with congenital heart disease].

OBJECTIVE: To investigate the relations between serum homocysteine (Hcy) and folic acid with congenital heart disease (CHD) in CHD nuclear families. METHODS: In Liaoning Province 151 CHD patients and their biological parents were selected as the case group, with another 98 normal subjects and their parents as control. For some filial individuals and their mothers the serum total Hcy (tHcy) levels were detected by fluorescence polarization immunoassay. And for all members the serum levels of folic acid and vitamin B12 (VB12) were determined by radio-immunoassay. RESULTS: There were not significantly differences in the serum tHcy and folic acid levels and theirs abnormality prevalence between CHD patients and the control, neither were their parents in the study. Compared with the control group the serum VB12 levels of CHD patients were apparently higher (315.36 pmol/L and 185.34 pmol/L, P < 0.05), and the VB12 deficiency prevalence of patients and their fathers were lower. Analysis of different CHD types showed that in ventricular septal defect patients the serum tHcy levels were lower than the control with VB12 levels higher, and in parents of patent ductus arteriosus patients the serum folic acid levels were increased (P < 0.05). The study also indicated that the folic acid and VB12 of parents were significantly positively associated with that of filial generation. In the case group the tHcy levels of mothers were positively correlated with filial generation, and in CHD patients the tHcy was negatively associated with folic acid. In filial individuals of the control group the tHcy was negatively related with VB12 (P < 0.05). CONCLUSION: Folic acid and VB12 were important influencing factors of serum Hcy and they were negatively correlated. In this study, the folic acid and Hcy were not significantly related with CHD, and it needs further investigations to confirm it. There were not significant differences in the serum tHcy and folic acid levels and theirs abnormality prevalence between CHD patients and the control, neither were their parents in the study. Compared with the control group the serum VB12 levels of CHD patients were apparently higher (315.36 pmol/L and 185.34 pmol/L, P < 0.05), and the VB12 deficiency prevalence of patients and their fathers were lower. Analysis of different CHD types showed that in ventricular septal defect patients the serum tHcy levels were lower than the control with VB12 levels higher, and in parents of patent ductus arteriosus patients the serum folic acid levels were increased (P < 0.05). The study also indicated that the folic acid and VB12 of parents were significantly positively associated with that of filial generation. In the case group the tHcy levels of mothers were positively correlated with filial generation, and in CHD patients the tHcy was negatively associated with folic acid. In filial individuals of the control group the tHcy was negatively related with VB12 (P < 0.05). CONCLUSION: Folic acid and VB12 were important influencing factors of serum Hcy and they were negatively correlated. In this study, the folic acid and Hcy were not significantly related with CHD, and it needsfurther investigations to confirm it.

Adolescent↗

PubMed2004

Elastic behavior of adsorbed polymer chains.

Elastic behaviors of single polymer chains adsorbed on the attractive surface are first investigated using Monte Carlo simulation method based on the bond fluctuation model. We investigate the chain size and shape of adsorbed chains, such as mean-square radius of gyration S2, mean-square bond length b2, shape factors sf(i) and delta*, and the orientation of chain segments P2 , to illuminate how the shape of polymer chains changes during the process of tensile elongation. There are some special behaviors of the chain size and shape at the beginning of elongation, especially for strong attraction interaction. For example, mean fraction of adsorbed segments decreases abruptly in the region of small elongation ratio and then decreases slowly with increasing elongation ratio. In fact, the chain size and shape also changes abruptly for small elongation ratio with strong attraction interaction. Some thermodynamics properties are also investigated here. Average Helmholtz free energy increases fast for elongation ratio lambda<1.15, especially with strong attraction, and increases slowly for lambda>1.15. Similar behaviors are obtained for average energy per bond. Elastic force (f ) and energy contribution to force (f(U)) are also studied, and we find that elastic force decreases abruptly for lambda<1.15, and there is a minimum of elastic force for strong attraction interaction, then increases very slowly with increasing elongation ratio. However, there are different behaviors for weak attraction interaction. For energy contribution to force (f(U)), there is a maximum value for strong attraction interaction in the region of lambda<1.15. Some comparisons with the atomic force microscopy experiments are also made. These investigations may provide some insights into the elastic behaviors of adsorbed polymer chains.

Journal Article↗

PubMed2004

Analysis of amino acid-carbohydrate mixtures by anion exchange chromatography and integrated pulsed amperometric detection.

A review is presented of recent developments in the area of analysis of amino acid-carbohydrate mixtures. Based on its broad selectivity, the AminoPac PA10 column exhibits a remarkable capability to perform simultaneous separations of amino acids and carbohydrates. This ability is further enhanced by the equal sensitivity for carbohydrates and amino acids exhibited by the "amino acid" integrated pulsed electrochemical detection (IPAD) waveforms. Equimolar levels of carbohydrates and amino acids are separated either by optimized elution gradients alone or by a combination of modified gradients and a bi-modal IPAD waveform. Samples containing large amounts of carbohydrates may be analyzed after suitable sample preparation. Both a manual off-line method and a fully automatic on-line method are discussed. In addition, we will review the application of these methods to various types of samples, including cell culture media, glycoprotein hydrolysates, beverages, condiments and soil extracts.

Amino Acids↗

PubMed2004

CarboPac PA20: a new monosaccharide separator column with electrochemical detection with disposable gold electrodes.

This report documents the development of a new monosaccharide separator column (CarboPac PA20, 3x150 mm) that allows fast, efficient monosaccharide separations with good spacing. It is based on a new chemistry with a reduced resin particle size (from 10 to 6.5 microm). Faster, more efficient separations of glycoprotein monosaccharides with better spacing were achieved across a range of isocratic NaOH concentrations at lower flow rates. Detection sensitivity was improved, enabling routine low to sub pmol monosaccharide determinations. Glycoprotein monosaccharides eluted in less than 10 min at a flow rate of 0.5 ml/min. Furthermore, when used with an AminoTrap guard column, the protein matrix consisting of amino acids and peptides (released by acid hydrolysis of glycoprotein) did not interfere with monosaccharide analysis. Compared to previous CarboPac columns (CarboPac PA1 and CarboPac PA10), the CarboPac PA20 has improved selectivity with respect to glycoprotein monosaccharides. The improved selectivity results in better separation of glucosamine and galactose, enabling the accurate determination of monosaccharide ratios for undergalactosylated glycoproteins. Finally, disposable gold working electrodes that eliminate the possibility of working electrode recession affecting peak area response were used.

Chromatography, Ion Exchange↗

PubMed2004

[Effects of methionine synthase gene variation in parents on occurence of congenital heart disease in offspring].

OBJECTIVE: To investigate the relations of methionine synthase (MS) gene variation in parents with congenital heart disease (CHD) phenotype in offspring. METHODS: We selected 192 CHD patients (93 males and 99 females) and their biological parents (nuclear families) in Liaoning Province as case group, and 104 normal people (60 males and 44 females) and their parents without family history of birth defects as control group. For all subjects the MS gene A2756G locus polymorphism was examined by PCR-RFLP method. The data were analyzed to compare the difference of gene variation between the case parents and controls, and to assess the genetic disequilibrium in the CHD nuclear families. RESULTS: The MS genotype distribution and allele frequencies of the case mothers were not different significantly from those of the control group (P>0.05). The frequency of allele (+) in the case fathers (5.0%) was lower than that of the control (9.1%, P=0.060). The odds ratio (OR) was 0.53 (95% CI: 0.25-1.09). There was no difference in parents' genotype combination between the two groups. The analysis of allele transmission indicated that mutation allele (+) transmission disequilibrium existed in CHD nuclear families. The percentage of allele (+) transmitted from the parents was lower than (-) with being OR 0.26 (95% CI: 0.11-0.60). CONCLUSION: The study shows that the MS gene variation at A2756G locus in parents is associated with occurrence of CHD in offspring, and the mutation allele (+) in parents might be related with the decrease of CHD risk in offspring.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗

PubMed2004

Cloning and identification of NS5ATP2 gene and its spliced variant transactivated by hepatitis C virus non-structural protein 5A.

AIM: To clone, identify and study new NS5ATP2 gene and its spliced variant transactivated by hepatitis C virus non-structural protein 5A. METHODS: On the basis of subtractive cDNA library of genes transactivated by NS5A protein of hepatitis C virus, the coding sequence of new gene and its spliced variant were obtained by bioinformatics method. Polymerase chain reaction (PCR) was conducted to amplify NS5ATP2 gene. RESULTS: The coding sequence of a new gene and its spliced variant were cloned and identified successfully. CONCLUSION: A new gene has been recognized as the new target transactivated by HCV NS5A protein. These results brought some new clues for studying the biological functions of new genes and pathogenesis of the viral proteins.

Antigens, Polyomavirus Transforming↗

PubMed2004

Transactivating effect of hepatitis C virus core protein: a suppression subtractive hybridization study.

AIM: To investigate the transactivating effect of hepatitis C virus (HCV) core protein and to screen genes transactivated by HCV core protein. METHODS: pcDNA3.1(-)-core containing full-length HCV core gene was constructed by insertion of HCV core gene into EcoRI/BamHI site. HepG2 cells were cotransfected with pcDNA3.1(-)-core and pSV-lacZ. After 48 h, cells were collected and detected for the expression of beta-gal by an enzyme-linked immunosorbent assay (ELISA) kit. HepG2 cells were transiently transfected with pcDNA3.1(-)-core using Lipofectamine reagent. Cells were collected and total mRNA was isolated. A subtracted cDNA library was generated and constructed into a pGEM-Teasy vector. The library was amplified with E. coli strain JM109. The cDNAs were sequenced and analyzed in GenBank with BLAST search after polymerase chain reaction (PCR). RESULTS: The core mRNA and protein could be detected in HepG2 cell lysate which was transfected by the pcDNA3.1(-)-core. The activity of beta-galactosidase in HepG2 cells transfected by the pcDNA3.1(-)-core was 5.4 times higher than that of HepG2 cells transfected by control plasmid. The subtractive library of genes transactivated by HCV core protein was constructed successfully. The amplified library contained 233 positive clones. Colony PCR showed that 213 clones contained 100-1 000 bp inserts. Sequence analysis was performed in 63 clones. Six of the sequences were unknown genes. The full length sequences were obtained with bioinformatics method, accepted by GenBank. It was suggested that six novel cDNA sequences might be target genes transactivated by HCV core protein. CONCLUSION: The core protein of HCV has transactivating effects on SV40 early promoter/enhancer. A total of 63 clones from cDNA library were randomly chosen and sequenced. Using the BLAST program at the National Center for Biotechnology Information, six of the sequences were unknown genes. The other 57 sequences were highly similar to known genes.

Gene Expression Regulation, Viral↗

PubMed2004

Laparoscopic placement of hepatic artery infusion pumps: technical considerations and early results.

BACKGROUND: Laparoscopic hepatic artery infusion pump (LHAIP) placement is a novel treatment option for patients with colorectal liver metastases. This study investigates technical difficulties with regard to variant hepatic arteries and the preliminary outcomes for patients treated with LHAIP placement. METHODS: Between March 1998 and January 2003, 38 patients with colorectal metastases confined to the liver, 35 (92%) of who had prior systemic chemotherapy that failed, were treated with LHAIP. RESULTS: Twelve patients (32%) had LHAIP placement only, and 26 (68%) had pump placement combined with laparoscopic radiofrequency ablation (LRFA; 24 patients) and/or liver resection (2 patients). Variant hepatic arterial (HA) anatomy was present in 18 patients (47%). The presence of a variant HA did not increase pump complications, operative time, or blood loss (P >/=.20) or decrease the functional time of pump use (P =.91) in comparison with normal anatomy. In all patients with a variant HA, laparoscopic ligation of the variant vessel and/or cannulation of nongastroduodenal artery resulted in complete hepatic perfusion. Three misperfusions identified intraoperatively with use of methylene blue injection were corrected by laparoscopic ligation (two) or postoperative angioembolization (one). Postoperative pump radionuclide flow studies confirmed isolated hepatic artery infusion in all cases. There was a 13% pump-related complication rate. During a median follow-up of 11 months (0.5 to 35.5 months), the actuarial rate of overall survival was 47% and the estimated median survival time was 17.5 months. CONCLUSIONS: LHAIP placement is technically feasible, and variant HA is not associated with increased pump complications or decreased pump functional time.

Aged↗

PubMed2004

Improved generation of C57BL/6J mouse embryonic stem cells in a defined serum-free media.

C57BL/6 is a well-characterized mouse strain that is used extensively for immunological and neurological research. The establishment of C57BL/6 ES cell lines has facilitated the study of gene-altered mice in a pure genetic background-however, relatively few such lines exist. Using a defined media supplement, knockout serum replacement (KSR) with knockout DMEM (KSR-KDMEM), we find that we can readily establish ES cell lines from blastocysts of C57BL/6J mice. Six lines were established, all of which were karyotypically normal and could be maintained in the undifferentiated state on mouse embryonic fibroblast (MEF) feeders. One line was further tested and found to be karyotypically stable and germline competent, both prior to manipulation and after gene targeting. For this cell line, efficiencies of cell cloning and chimera generation were greater when maintained in KSR-KDMEM. Our work suggests that the use of defined serum-free media may facilitate the generation of ES cells from inbred mouse strains.

Animals↗

PubMed2004

Expression of vascular endothelial growth factor and receptor flk-1 in colon cancer liver metastases.

BACKGROUND/PURPOSE: This study investigated vascular endothelial growth factor (VEGF) and flk-1 expression in hepatic metastases from colon carcinoma, and their associations with tumor angiogenesis, proliferation, and apoptosis. METHODS: Immunohistochemical studies were performed for VEGF/flk-1, Ki-67, p53, and bcl-2 expression, and microvessel density (MVD) in surgical specimens from 35 patients who underwent hepatectomy for colon cancer liver metastases between 1986 and 2001. RESULTS: VEGF and flk-1 were expressed mainly in the cytoplasm of tumor cells. High VEGF expression was associated with high flk-1 expression (P = 0.043). MVDs of less than 15 and 15 or more were found in 5 (14.3%) and 30 (85.7%) of 35 hepatic metastases, respectively. A Ki-67 index (KI) of 50% or more was detected in 33/35 (94.3%) of tumors, and 23 of these (65.7%) showed a KI of 85% or more. A KI of less than 50% was present in 2/35 (5.7%) of tumors. The expression of VEGF/flk-1 was related to elevated MVD (P < or = 0.026). VEGF was also associated with an increased KI (P = 0.025). Mutant p53 and bcl-2 expressions were detected in 26/35 (74.3%) and 17/35 (48.6%) of liver metastases, respectively. Mutant p53 was not related to VEGF/flk-1 expression, but bcl-2 was highly associated with flk-1 (P = 0.007). The incidences of high flk-1 expression and a KI of 85% or more were significantly higher in tumors which were both p53- and bcl-2-positive (93.3% and 73.3%) than in tumors which were negative for both (42.9% and 14.3%; P < or = 0.021). CONCLUSIONS: The VEGF-flk-1 system takes part in tumor angiogenesis, proliferation, and apoptosis in colon liver metastases. The bcl-2 pathway may upregulate VEGF activity via the flk-1 receptor. These findings are preliminary, requiring a larger sampling in order to elucidate the role of VEGF/flk-1 in metastatic colon cancer.

Adult↗

PubMed2004

Laparoscopic biliary reconstruction.

BACKGROUND: Biliary reconstruction represents a relatively untested frontier in laparoscopy. METHODS: Retrospective review of all patients who underwent laparoscopic biliary operations at Legacy Health System from 1998 to 2003. RESULTS: Seven patients underwent laparoscopic biliary reconstruction. Indications included benign calculous disease in 4 patients, benign stricture on 1 patient, choledochal cyst in 1 patient, and malignant biliary obstruction in 1 patient. Operations performed included choledochoduodenostomy, hepaticojejunostomy, stricturoplasty, choledochal cyst excision with hepaticojejunostomy, and cholecystojejunostomy. Median operative time was 300 minutes. Median hospital stay was 4 days. One perioperative complication of a bowel obstruction required reoperation. Median follow-up was 15 months. One patient died of metastatic cancer 8 months after surgery. All other patients are symptom free with no signs of stricture or recurrent biliary obstruction. CONCLUSIONS: Laparoscopic biliary reconstruction represents a viable treatment option in carefully selected patients.

Adult↗

PubMed2004

Tetracycline-regulated transactivators driven by the involucrin promoter to achieve epidermal conditional gene expression.

To achieve conditional gene expression in the differentiated layers of the epidermis, we generated transgenic mice with the tetracycline-regulated transactivator proteins, tTA (tetracycline transactivator) and rtTA (reverse tetracycline transactivator), expressed from the human involucrin promoter. Interaction with tetracycline turns off or turns on the tTA and rtTA molecules, respectively, allowing for regulation of downstream target genes during development and postnatally. These transactivator lines were crossed with reporter mice driving LacZ expression from a tetracycline response element to analyze the specificity and levels of target gene expression. Quantitative beta-galactosidase experiments demonstrate a 30-fold induction, specific to epithelial tissues. Immunohistochemistry results illustrate that the beta-galactosidase staining follows that of endogenous involucrin expression. Induction initiates at embryonic day 14.5 with expression over the entire epidermal surface by E16.5. Together with other driver lines, expressing tetracycline transactivators in the mitotically active layers of the epidermis, these mice will allow investigators to specifically modulate expression of target genes to specific stages of epidermal differentiation.

Animals↗

PubMed2004

Basement membrane-type heparan sulfate proteoglycan (perlecan) and low-density lipoprotein (LDL) are co-localized in granulation tissues: a possible pathogenesis of cholesterol granulomas in jaw cysts.

BACKGROUND: As perlecan contains a low-density lipoprotein (LDL) receptor-like repeats in the second domain of its core protein, LDL may be bound to perlecan, which is rich in granulation tissues. We wanted to study if this is the case in the cyst wall of radicular cysts, which are often associated with cholesterol granuloma. METHODS: Thirty-three specimens of radicular cyst with cholesterol granulomas were immunohistochemically examined for comparative localizations of perlecan, apoprotein B (apo B), and oxidized LDL (Ox-LDL), and for mRNA expression levels for perlecan. RESULTS: Myxoid or edematous stroma of immature granulation tissues was strongly positive for perlecan and simultaneously for apo B and Ox-LDL. Macrophages including foamy cells scattered in the granulation tissues were also immunopositive for Ox-LDL and occasionally for apo B. In situ hybridization showed that fibroblasts, endothelial cells, and pericytes had strong signals for perlecan, which was also confirmed by RT-PCR. CONCLUSION: These results suggest that perlecan, which is abundantly produced and accumulated in the cyst wall of immature granulation tissue, traps Ox-LDL locally, and that Ox-LDL is phagocytosed by macrophages. Thus, LDL-laden foamy macrophages are aggregated in the granulation tissue, and free cholesterol from ruptured macrophages may be concentrated locally to be crystallized, which may induce foreign body granulomas in the cyst wall.

Animals↗

PubMed2004

Intraepithelial expression of perlecan, a basement membrane-type heparan sulfate proteoglycan reflects dysplastic changes of the oral mucosal epithelium.

BACKGROUND: Intercellular deposition of perlecan, a major heparan sulfate proteoglycan (HSPG) of the basement membrane, is known to result in characteristic stellate reticulum-like structures in ameloblastomas or tooth germs. Although enlargement of the intercellular space is one of the histological characteristics of epithelial dysplasia of oral mucosa, the mode of expression of perlecan is poorly understood in these epithelial lesions. METHODS: Eighty-two biopsy specimens consisting of normal and hyperplastic epithelium, epithelial dysplasia, and squamous cell carcinomas were examined for both perlecan core protein and heparan sulfate (HS) chains by immunohistochemistry and in situ hybridization. RESULTS: In normal and hyperplastic epithelium, perlecan core protein and HS chains were localized in the cell border of parabasal cells and lower prickle cells, and HS chains were also found in basal cells. With an increase in the severity of epithelial dysplasia, the core protein was heavily and extensively deposited in the interepithelial space as well as in the cytoplasm of epithelial cells from the basal to the surface layers. Its gene expression was confirmed in the cells around the protein deposits. On the other hand, HS chains were enhanced in mild dysplasia, but decreased in moderate and severe dysplasias. In squamous cell carcinomas, either the core protein or HS chains were found scarcely in tumor cells but abundantly in the stromal space. CONCLUSIONS: The findings indicate that perlecan is localized in the intercellular space of the oral epithelia, and that it is over-expressed in dysplastic epithelial cells and is deposited in their interepithelial space, which results in the histology of reduction of cellular cohesion.

Carcinoma, Squamous Cell↗