Effect of overexpression of LYRM1 gene on reactive oxygen species in skeletal muscle cells / 中华实用儿科临床杂志

Objective To explore the effect of LYRM1 overexpression on production of reactive oxygen species (ROS) in skeletal muscle cells.Methods Rat myoblasts(L6) were transfected with either an empty vector or a LYRM1 expression vector.Cells were screened and the expression of LYRM1 protein in cells was identified.L6 cells were incubated in culture solution with H2-DCFDA after they were differentiated.Then fluorescence intensity of ROS in L6 was observed by fluorescence microscope,and the content of ROS was determined by flow cytometry.Results The relative fluorescence intensity of ROS in L6 overexpressing LYRM1 was 24.8933 ± 4.4574,while that in contrast cells was 13.1512 ± 0.7347,the difference between them was significant(t =24.12,P =0.00).Conclusions Overexpression LYRM1 can increase the production of ROS in skeletal muscle cells.LYRM1 overexpression may be influence the mitochondrial function and induce the mitochondrial damage of skeletal muscle cells.

Evaluation of 3-day smoking cessation training course for doctors from 38 cities in China / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The World Health Organization's "Framework Convention on Tobacco Control" came into effect in China in 2006. Since then, a series of tobacco control measures has been undertaken, including the first step to establish a coordinated network of stop-smoking clinics in Chinese hospitals. Training for stop-smoking specialists has been traditionally provided via printed materials. This study evaluated the outcomes of the first two intensive 3-day courses in smoking cessation in China run in collaboration with experts who provide training to UK Specialist Stop Smoking Service.</p><p><b>METHODS</b>Eighty-four doctors from 38 cities in China responsible for stop-smoking treatment in 20 provinces and four autonomous regions participated in the training courses. Participants' knowledge competencies and self-efficacy were assessed before and after the authentication training.</p><p><b>RESULTS</b>The training significantly improved participants' knowledge, skills and self-efficacy across different domains. Forty-eight participants were finally certified as "smoking cessation specialist".</p><p><b>CONCLUSIONS</b>The UK model of face-to-face training was acceptable and effective in China. A relatively brief intensive training program can generate significant improvements in skills, knowledge, and readiness to engage in smoking cessation activities.</p>

Resistin inhibits rat insulinoma cell RINm5F proliferation / 中国当代儿科杂志

<p><b>OBJECTIVE</b>Resistin was thought to link the obesity to type 2 diabetes. This study aimed to investigate the effect of resistin on insulinoma cell proliferation.</p><p><b>METHODS</b>pcDNA3.1-resistin was transfected into rat insulinoma cells RINm5F. Cell proliferation was assessed by the MTT assay. The resistin and SOCS3 mRNA levels were assessed by RT-PCR. The total Akt level and the phosphorylation status were assessed by Western blot.</p><p><b>RESULTS</b>The over-expressed resistin inhibited the RINm5F cell proliferation (p<0.05). SOCS-3 expression was up-regulated by resistin over-expression (3.2 folds over the control; p<0.05). Akt phosphorylation was down-regulated by resistin over-expression (0.6 fold over the control; p<0.05).</p><p><b>CONCLUSIONS</b>Resistin impairs the rat insulinoma cell RINm5F proliferation. This might be attributed to a down-regulation of Akt level caused by increased SOCS-3 expression.</p>

Effects of NYGGF4 gene over-expression on the insulin sensitivity and secretory function of adipocytes / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the effect of a new obesity-related gene NYGGF4 on the insulin sensitivity and secretory function of adipocytes.</p><p><b>METHODS</b>3T3-L1 preadipocytes transfected with either an empty expression vector (pcDNA3.1; control group) or an NYGGF4 expression vector (NYGGF4-pcDNA3.1) were cultured in vitro and differentiated into the matured adipocytes with the standard insulin plus dexamethasone plus 3-isobutyl-methylxanthine (MDI) induction cocktail. 2-deoxy-D-[3H] glucose uptake was determined by liquid scintillation counting. Western blot was performed to detect the protein content and translocation of glucose transporter 4 (GLUT4). The supernatant concentrations of TNF-alpha, IL-6, adiponectin and resistin were measured using ELISA.</p><p><b>RESULTS</b>NYGGF4 over-expression in 3T3-L1 adipocytes reduced insulin-stimulated glucose uptake. NYGGF4 over-expression impaired insulin-stimulated GLUT4 translocation without affecting the total protein content of GLUT4. The concentrations of TNF-alpha, IL-6, adiponectin and resistin in the culture medium of 3T3-L1 transfected with NYGGF4 were not significantly different from those in the control group.</p><p><b>CONCLUSIONS</b>NYGGF4 over-expression impairs the insulin sensitivity of 3T3-L1 adipocytes through decreasing GLUT4 translocation and had no effects on the secretory function of adipocytes.</p>

Regulative role of TNFalpha on STEAP4 gene in matured human adipocytes / 中国当代儿科杂志

<p><b>OBJECTIVE</b>Human STEAP4, a novel obesity-related gene, is associated with insulin sensitivity regulation in human adipocytes. This study aimed to explore the regulative role of TNFalpha on STEAP4 gene in matured human adipocytes.</p><p><b>METHODS</b>Human preadipocytes were cultured and differentiated into matured adipocytes in vitro. Fully differentiated adipocytes (Day 17) were treated with different concentrations of TNFalpha (0, 5, 10, 25 and 50 ng/mL) for 24 hrs. Total RNA and protein were extracted from the adipocytes. Levels of STEAP4 mRNA and protein expression were determined by real-time quantitative RT-PCR and Western blot respectively.</p><p><b>RESULTS</b>Different concentrations (5, 10, 25 and 50 ng/mL) of TNFalpha treatment for 24 hrs resulted in a significant increase in the STEAP4 mRNA expression of human matured adipocytes.The maximal effect was seen in the 50 ng/mL of TNFalpha treatment group. In parallel, STEAP4 protein synthesis in matured adipocytes increased in response to TNFalpha treatment of different concentrations (5, 10, 25 and 50 ng/mL) for 24 hrs. The maximal up-regulated effect was seen in the 25 ng/mL of TNFalpha treatment group.</p><p><b>CONCLUSIONS</b>TNFalpha can up-regulate STEAP4 mRNA expression in human matured adipocytes.</p>

Comparative ultrastructural study of parotid gland, lacrimal gland and pituitary gland between miniature pig and mouse / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the ultrastructure of parotid glands, lacrimal glands and pituitary glands between miniature pig and mouse.</p><p><b>METHODS</b>Five adult miniature pigs and 5 mice were studied. Ultrastructure of their parotid glands, lacrimal glands, and pituitary glands was observed.</p><p><b>RESULTS</b>The secretary granules in acinar cell of miniature pig parotid glands showed higher density and more aequalis than those of mice. The cell apparatus in acinar cell of mouse parotid glands were more plentiful than those of miniature pigs. The secretary granules on blood vessel wall were richer in parotid gland of miniature pigs compared with mouse parotid gland. Lacrimal gland had the similar ultrastructure to parotid gland in these two animals. Many blood vessel antrum were found in pituitary glands of these two animals.</p><p><b>CONCLUSIONS</b>Compared with mouse parotid glands, there are more secretary granules in acinar cells and vascular endothelial cells in miniature pig parotid glands, which might enter blood stream and have function of endocrine secretion.</p>

Analysis of TGFBI gene mutation in a Chinese family with atypical Reis-Buckler corneal dystrophy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify the TGFBI gene mutation and the relationship between genotype and phenotype of a Chinese family with atypical Reis-Buckler corneal dystrophy (RBCD).</p><p><b>METHODS</b>Four patients, two non-carrier relatives of the family were enrolled in the present study. In addition to ophthalmologic examinations, PCR amplification and DNA sequencing of exons 4, 11, 12, and 14 of the TGFBI gene were carried out. Exon 14 was also sequenced in 100 healthy controls.</p><p><b>RESULTS</b>A G to A transition at codon 623 in all affected members was identified. This mutation resulted in a substitution of glycine (GGC) to aspartic acid (GAC) at the protein level.None of the healthy family members, or any of the 100 control subjects carried this mutation.</p><p><b>CONCLUSION</b>The G623D mutation of the TGFBI gene caused an atypical Reis-Buckler corneal dystrophy in this family. This mutation is reported in Chinese for the first time.</p>

Effect of same-dose single or dual field irradiation on damage to miniature pig parotid glands / 国际口腔科学杂志·英文版

<p><b>AIM</b>To evaluate the effect of single or dual field irradiation (IR) with the same dose on damage to miniature pig parotid glands.</p><p><b>METHODOLOGY</b>Sixteen miniature pigs were divided into two IR groups (n=6) and a control group (n=4). The irradiation groups were subjected to 20 Gy X-radiation to one parotid gland using single-field or dual-field modality by linear accelerator. The dose-volume distributions between two IR groups were compared. Saliva from parotid glands and blood were collected at 0, 4, 8 and 16 weeks after irradiation. Parotid glands were removed at 16 weeks to evaluate tissue morphology.</p><p><b>RESULTS</b>The irradiation dose volume distributions were significantly different between single and dual field irradiation groups (t=4.177, P=0.002), although dose volume histogramin (DVH) indicated the equal maximal dose in parotid glands. Saliva flow rates from IR side decreased dramatically at all time points in IR groups, especially in dual field irradiation group. The radiation caused changes of white blood cell count in blood, lactate dehydrogenase and amylase in serum, calcium, potassium and amylase in saliva. Morphologically, more severe radiation damage was found in irradiated parotid glands from dual field irradiation group than that from single field irradiation group.</p><p><b>CONCLUSION</b>Data from this large animal model demonstrated that the radiation damage from the dual field irradiation was more severe than that of the single field irradiation at the same dose, suggesting that dose-volume distribution is an important factor in evaluation of the radiobiology of parotid glands.</p>

Role of mitogen-activated protein kinase pathway in chloracne / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the role of mitogen-activated protein kinase (MAPK) signal transduction pathway in chloracne.</p><p><b>METHODS</b>Immunohistochemical technique was used to detect the expression of phosphorylated epidermal growth factor receptor (p-EGFR) and p-MAPK proteins in the epithelium of chloracne group and control group.</p><p><b>RESULTS</b>p-EGFR and p-MAPK was found in all chloracne tissues, whereas no expression of p-EGFR and p-MAPK protein was found in control group. In the skin of chloracne patients, p-EGFR was mainly distributed in the membrane and the cytoplasm, especially in the vicinity of membrane; major positive signal of p-MAPK was in core and serosity.</p><p><b>CONCLUSION</b>EGFR and MAPK phosphorylation is found in chloracne tissues. MAPK signal transduction pathway is one important molecular mechanism of chloracne.</p>

Effect of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin on the expression of AhR and TGF-alpha / 中华预防医学杂志

<p><b>OBJECTIVE</b>To study HaCaT-keratinocyte cell lines, a chosen model of human epidermis in an attempt to analyze the mRNA expression of AhR and TGF-alpha induced by TCDD METHODS: Semi-quantitative reverse transcription PCR-technique was used for assaying the relative levels of AhR and TGF-alpha mRNA of HaCaT-cells during the proliferation period when the cells were cultured for 24 hours.</p><p><b>RESULTS</b>Relative level of the AhR-transcripts (corrected with beta-actin) decreased with the elevated concentration of TCDD and the relevant coefficient between the proliferation rate and concentration was -0.548, and the differences among all groups were significant (F =4.124, P =0.021). The vehicle control was respectively compared with 7 x 10(-10) mol/L (0.0620 +/- 0.0085) and 7 x 10(-9) mol/L (0.0518 +/- 0.0194) group, significantly different from the control group (0.1138 +/- 0.0227) (t = -3.48, P <0.05; t = -4.17, P <0.01), the expression amount being 55% and 45% of the control. Relative levels of TGF-alpha mRNA tended to increase with the elevated concentration with the significant coefficient of 0.695 (P < 0.01), and the differences among all groups were significant (F = 15.789, P =0.000). In two higher concentration group 7 x 10(-10) mol/L (0.1474 +/- 0.0390) and 7 x 10 (-9) mol/L (0.2133 +/- 0.0364), their relative expression amount of TGF-alpha mRNA was 2.6-fold, 3.8-fold of the control group (0.0561 +/- 0.0100) respectively. Further analysis for the relevant relationship between the amounts of the AhR mRNA and TGF- alpha mRNA showed a highly negative correlation, the coefficient being - 0.561 (P <0.05).</p><p><b>CONCLUSIONS</b>TCDD down-regulate the expression of AhR and up-regulate the expression of TGF-alpha. A strong negative correlation between AhR and TGF-alpha expression is found.</p>

Study on growth and dry substance accumulation of Curcuma longa / 中国中药杂志

<p><b>OBJECTIVE</b>To explore the growth characteristics of Curcuma longa, and provide basis for standardized cultivation.</p><p><b>METHOD</b>Plant samples were collected and investigated periodically.</p><p><b>RESULT</b>According to the growth of different parts and the characteristics of dry substance accumulation of C. longa, the development of C. longa could be divided into five stages: emergence of seedlings, seedling, leaf, root tuber expansion, and dry substance accumulation of root tuber. In terms of number, leaf of C. longa increases gradually from one at first to eight at the final stage. Leaf size increases at a very low speed at the stage of seedling. However, leaves expands their sizes at a much higher speed at the stage of leaf. The dry substance in different parts accumulates increasingly with the development of C. longa dry substance mainly accumulates in leaves at the stage of leaf, and in rhizome at the stage of root tuber expansion. At the final stage, it mainly accumulates in root tuber.</p><p><b>CONCLUSION</b>Cultivation technologies of C. longa and the relevant management methods could be established according to the growth of different parts of C. longa and the characteristics of dry substance accumulation in different stages.</p>

Resistin Binding Peptide Stimulates Basal Insulin Secretion of RINm5F Insulinoma Cells / 实用儿科临床杂志

Objective A resistin binding peptide (RBP) was selected by phage display in our previous work. Studies had shown that RBP could antagonize the role of resistin on the lipid metabolism and endocrine function of adipose tissue, but whether RBP affects the insulin secretion of pancreatic cells is still unknown. The aim of this study is to assess the effect of RBP on basal insulin secretion in RINm5F insulinoma cells. Methods The cell viability was measured by 3-[4,5-dimethyhhiazol-2-yl]-2,5-diphenyltetra-zolium bromide (MTT) cytotoxicity assay. The supernatants were assayed for insulin content by enzyme linked immunosorbent assay (ELISA). Reverse transcriptase-PCR assay and Western blotting were used to determine the expression of glucose transporter 2 (GLUT2) involved in insulin secretion. Cytosolic Ca2+, the trigger of insulin exocytosis, was analyzed with the fluorescent probe FURA-3/AM. Results RBP did no effect on the cell viability with a concentration of 10-8-10-12mol/L of 2 hours intervention. But it stimulated basal insulin secretion of RINm5F cells, accompanied by up-regulated increased expression of GLUT2 and elevated concentration of cytosolic Ca2+. Conclusion RBP could stimulate basal insulin secretion without affecting the cell viability.

Alterations of salivary flow rate and oral main pathogens in miniature pig with bilateral parotid gland atrophy / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To observe the effect of bilateral parotid gland atrophy on the whole saliva flow rate and the growth of main oral pathogens in different sites of oral cavity.</p><p><b>METHODS</b>Ten healthy miniature pigs were divided into two groups. The parotid glands of test group (n = 5) were bilaterally ablated by methyl violet. Another healthy five miniature pigs served as the control group. Whole saliva was collected and the whole saliva flow rate detected in both groups at 12 and 24 months respectively after parotid atrophy. The total numbers of oral main pathogens in the first molar, cuspid sub-gingival bacteria plaque and whole saliva were also detected.</p><p><b>RESULTS</b>The whole saliva flow rate was significantly decreased at both 12 and 24 months respectively after atrophy of bilateral parotid gland in miniature pig. Pathogens including Streptococcus mutans, Porphyromonas gingivalis and Fusobacterium nucleatum in different sites oral cavity were increased after bilateral parotid gland atrophy.</p><p><b>CONCLUSIONS</b>Bilateral ablation of the parotid glands led to a significant decrease of whole saliva flow rate. The total numbers of main oral pathogens were increased in different sites of oral cavity.</p>

The key of increasing the therapeutic effect of scalp acupuncture on hemiplegia due to stroke / 中国针灸

Discuss the 5 aspects for increasing the therapeutic effect of scalp acupuncture for treatment of hemiplegia due to stroke. First is deqi (getting qi), which is an important factor for acupuncture effect, and the needling sensation of scalp acupuncture should be the feeling of sucking the needle as main; second is needling manipulation, which should be selected for getting proper needling sensation, conducting direction and intensity; third is effective stimulating amount, only stimulating intensity and amount match with response state in the body of the patient, can produce resonance of energy, and attain the best therapeutic effect; fourth is treatment opportunity: the increase of rehabilitation level for hemiplegia of stroke depends on early scalp acupuncture treatment; fifth is rehabilitation training: scalp acupuncture needs combination with rehabilitation training in scalp acupuncture treatment of hemiplegia of stroke to exert positive effects. Clinically, taking note of these five aspects, the therapeutic effects of scalp acupuncture on hemiplegia of stroke can be consolidated and increased.

Antimicrobial effect of acidified nitrate and nitrite on six common oral pathogens in vitro / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Salivary nitrate is positively correlated with plasma nitrate and its level is 9 times the plasma level after nitrate loading. Nitrate in saliva is known to be reduced to nitrite by oral bacteria. Nitrate and nitrite levels in saliva are 3 - 5 times those in serum in physiological conditions respectively in our previous study. The biological functions of high salivary nitrate and nitrite are still not well understood. The aim of this in vitro study was to investigate the antimicrobial effects of nitrate and nitrite on main oral pathogens under acidic conditions.</p><p><b>METHODS</b>Six common oral pathogens including Streptococcus mutans NCTC 10449, Lactobacillus acidophilus ATCC 4646, Porphyromonas gingivalis ATCC 33277, Capnocytophaga gingivalis ATCC 33624, Fusobacterium nucleatum ATCC 10953, and Candida albicans ATCC 10231 were cultured in liquid medium. Sodium nitrate or sodium nitrite was added to the medium to final concentrations of 0, 0.5, 1, 2, and 10 mmol/L. All of the microorganisms were incubated for 24 to 48 hours. The optical densities (OD) of cell suspensions were determined and the cultures were transferred to solid nutrient broth medium to observe the minimum inhibitory concentration and minimum bactericidal/fungicidal concentration for the six tested pathogens.</p><p><b>RESULTS</b>Nitrite at concentrations of 0.5 to 10 mmol/L had an inhibitory effect on all tested organisms at low pH values. The antimicrobial effect of nitrite increased with the acidity of the medium. Streptococcus mutans NCTC 10449 was highly sensitive to nitrite at low pH values. Lactobacillus acidophilus ATCC 4646 and Candida albicans ATCC 10231 were relatively resistant to acidified nitrite. Nitrate at the given concentrations and under acidic conditions had no inhibitory effect on the growth of any of the tested pathogens.</p><p><b>CONCLUSION</b>Nitrite, at a concentration equal to that in human saliva, is both cytocidal and cytostatic to six principal oral pathogens in vitro, whereas nitrate at a similar concentration has no antimicrobial effect on these organisms.</p>

Effect of single dose irradiation to parotid gland on the structured and function changes of bilateral parotid glands in miniature pig / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effects of a solitary megadose protocol of ionizing radiation (IR) to parotid gland on the structured and function changes of bilateral parotid glands in miniature pig.</p><p><b>METHODS</b>Fourteen minipigs were subjected to either 15 or 20 Gy to one parotid gland with a linear accelerator, while another four minipigs served as non-IR controls. Salivary flow rates and salivary chemistries were measured pre-IR, and 4 and 16 weeks post-IR. A quantitative assessment of gland weight and acinar area, and detailed serum chemistry and hematological analyses, were also performed.</p><p><b>RESULTS</b>Parotid gland weights were significantly decreased in the 15 and 20 Gy groups at 4 and 16 weeks post-IR. The acinar cell area in glands of both IR groups was significantly reduced. Parotid flow rates decreased by 60% with 15 Gy at 16 weeks post-IR. In the 20 Gy group, salivary flow rates were reduced by 80% at 16 weeks post-IR. Additionally, parotid flow rates significantly reduced in contralateral glands with 20 Gy at 16 weeks, while structure and weight did not changes in parotid glands.</p><p><b>CONCLUSION</b>Structural changes in salivary gland parenchyma occurred relatively early after IR, while the alterations in salivary output were relatively delayed. Further, reductions in salivary flow were not proportional to acinar cell area loss. There isn't a significant structured change of contralateral glands, but significant reduction of parotid flow rate at this time.</p>

Morphological characteristics of submandibular glands of miniature pig / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Miniature pig (minipig) is increasingly used as a large animal model for a variety of biomedical studies. Little information is available in the literature on anatomy, histology and sialograghy of the submandibular gland of the minipig. The purpose of this study was to characterize the morphology of a miniature pig's (minipig) submandibular gland as a large animal model for further biomedical studies.</p><p><b>METHODS</b>Five minipigs were subjected to sialographic, anatomic, histologic, histochemical and ultrastructural evaluations for submandibular glands.</p><p><b>RESULTS</b>Sialograms showed a long, horizontal main excretory duct and a pear-shaped gland located inferoposterior to the angle of the mandible. The submandibular glands lied superficial to the suprahyoid, and infrahyoid muscle groups, and were covered by the inferior portion of the parotid gland. The submandibular glands were characterized by a mixed parenchyma of mucous and serous secretory acini. Alcian blue (AB) staining and periodic acid-Schiff (PAS) reactions demonstrated that minipig submandibular glands synthesized and secreted acid mucous substances by serous cells and polysaccharide, and neutral mucous substances, by mucous cells.</p><p><b>CONCLUSION</b>The submandibular gland of the minipig is considered a useful large salivary gland animal model for biomedical studies.</p>

Significance of p53 gene mutation and P53 protein expression abnormality on the prognosis of esophageal cancer: a meta-analysis study / 中华流行病学杂志

<p><b>OBJECTIVE</b>To evaluate the prognostic significance of p53 mutation and P53 protein expression abnormality among esophageal cancer.</p><p><b>METHODS</b>The results of 27 random controlled trials from 1990 to 2003 were analyzed by meta-analysis method. The overall positive rate of p53 was 52.9% among the cumulative 2174 cases. Relative hazard (RH) was applied to evaluate the risk of disease and all data were analyzed by Dersimonian-Laird method.</p><p><b>RESULTS</b>The analysis for homogeneity (q statistics test) showed that all eligible studies were with heterogeneity (q = 59.88, P < 0.005). The combined RH was 2.07 and 95% confidence interval was 1.58-2.70.</p><p><b>CONCLUSION</b>Findings showed that p53 was a poor prognosis biomarker for esophageal cancer gene diagnosis but might benefit to the strategy of treatment.</p>

Expression of STEAP4 Gene during the Period of Human Preadipocyte Differentiation / 实用儿科临床杂志

Objective To observe the expression of STEAP4 gene(a novel obesity-related gene) during the period of human preadipocyte differentiation and to explore the relationship between the STEAP4 gene expression and adipocytes differentiation,adipogenesis.Methods Human preadipocytes were cultured and differentiated into the matured adipocytes in vitro.Adipocytes morphology and lipid accumulation were observed during this process.Total RNA was extracted from adipocytes at various time points (preadipocyte,Day 0,Day 4,Day 6,Day 8,Day 11,Day 14,and Day 17) and the level of STEAP4 mRNA expression was measured by fluorescent real-time quantitative reverse transcriptase-polyme-rase chain reaction(RT-PCR).Results The level of STEAP4 mRNA expression remained high in preadipocytes.In the presence of differentiation medium (Day 4),there was a transient upregulation in the expression of STEAP4 gene.After that,with the human preadipocytes being differentiated into matured adipocytes,the expression of STEAP4 mRNA was downregulated and reached the lowest level in fully differentiated adipocytes.There was a significant difference between any 2 detected phases in the level of STEAP4 mRNA expression (Pa

Cloning and polymorphism analysis of prtH gene from Porphyromonas gingivalis / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To clone the prtH gene from Porphyromonas gingivalis (P.g) ATCC 33277 and analyze the polymorphism of prtH gene from 5 strains of P.g in order to explore the relationship between P.g and periodontitis.</p><p><b>METHODS</b>Using PCR, the prtH was amplified and cloned into pGEM-T vector. To illustrate the prtH polymorphism among P.g strains, the genomic DNAs were extracted and screened by PCR with three pairs of specific primers, dot blot and Southern blot hybridization using the biotin-labeled prtH sequence as probe.</p><p><b>RESULTS</b>Recombinant DNA pGEM-T- prtH was verified by restriction endonuclease and sequence assay. Strain W 381 and ATCC 33277 showed the identical results in PCR and hybridization assays, whereas strain ATCC 49417 and 14-3-2 revealed individual hybridization patterns. Strain 47A-1 seemed even not to contain prtH gene.</p><p><b>CONCLUSIONS</b>Different prtH gene sequences exist in different P.g strains. This polymorphism may indicate various potential virulent effects during the infection and pathogenesis. Established PCR protocol is sensitive for identification of prtH gene.</p>