Population Pharmacokinetics Modeling of Vancomycin Among Chinese Infants With Normal and Augmented Renal Function.

There have been good amounts of population pharmacokinetics (PPK) models of vancomycin for Chinese pediatric patients, but none of them had a special focus on modeling infant population with different levels of renal function. Since renal function variability is prominent among infant population and the clearance (CL) of vancomycin is heavily related to renal excretion, it is important to establish precise PPK models based on individual renal function levels. We employed a PPK approach to develop three models of vancomycin in parallel for Chinese pediatric patients with normal renal function [estimated glomerular filtration rate (eGFR) between 30 and 86 ml/min/1.73 m2, Model 1], with augmented renal function (eGFR ≥ 86 ml/min/1.73 m2, Model 2), or with all levels of renal function (Model 3). Three one-compartment models with first-order elimination kinetics were established. The predictive ability of Model 1 and Model 2 among each certain population is comparable with that of Model 3 with no statistical difference. Our study revealed that among the infant population with augmented renal function, only body weight was included as a covariate, which indicated that for an infant whose eGFR ≥ 86 ml/min/1.73 m2, taking blood sample is not compulsory for predicting vancomycin blood concentration, which avoids unnecessary injury to vulnerable infants.

Dose tailoring of tacrolimus based on a non-linear pharmacokinetic model in children with refractory nephrotic syndrome.

The population pharmacokinetics (PPK) of tacrolimus (TAC) in children with refractory nephrotic syndrome (RNS) have not been well-characterized. This study aimed to investigate the significant factors affecting the TAC PPK characteristics of children with RNS and to optimize the dosing regimen. A total of 494 concentrations from 108 children were obtained from routine therapeutic drug monitoring between 2016 and 2018. Information regarding the demographic features, laboratory test results, genetic polymorphisms of CYP3A5 (rs776746) and co-therapy medications were collected. PPK analysis was performed using the nonlinear mixed-effects modelling (NONMEM) software and two modelling strategies (the linear one-compartment model and nonlinear Michaelis-Menten model) were evaluated and compared. CYP3A5 genotype, weight, daily dose of TAC and daily dose of diltiazem were retained in the final linear model. The absorption rate constant (Ka) was set at 4.48 h-1 in the linear model, and the apparent clearance (CL/F) and volume of distribution (V/F) in the final linear model were 14.2 L/h and 172 L, respectively. CYP3A5 genotype, weight and daily dose of diltiazem were the significant factors retained in the final nonlinear model. The maximal dose rate (Vmax) and the average steady-state concentration at half-Vmax (Km) in the final nonlinear model were 2.15 mg/day and 0.845 ng/ml, respectively. The nonlinear model described the pharmacokinetic data of TAC better than the linear model in children with RNS. A dosing regimen was proposed based on weight, CYP3A5 genotype and daily dose of diltiazem according to the final nonlinear PK model, which may facilitate individualized drug therapy with TAC.

Vincristine-induced peripheral neuropathy: A mini-review.

Vincristine (VCR), an alkaloid extracted from vinca, is often used in combination with other chemotherapeutic drugs to treat a variety of cancers, such as acute lymphoblastic leukaemia (ALL), malignant lymphoma, and neuroblastoma. However, VCR possesses dose-dependent neurotoxicity, which is the main factor restricting its application. Vincristine-induced peripheral neuropathy (VIPN) not only limits the dose of VCR and leads to the discontinuation of treatment but also triggers serious damage to the physical and mental health of patients. In addition, VIPN brings huge healthcare costs to patients and society. Individuals with VIPN often exhibit mechanical allodynia, sensory/tactile disorders, and numbness in the hands and feet. Unfortunately, VIPN is easily ignored due to its variable symptoms, which gives rise to insufficient research on the aetiology and pathogenesis of this disease, thereby resulting in a lack of appropriate preventive and therapeutic management. We performed a comprehensive review of the latest findings on VIPN in terms of symptoms, risk factors, potential mechanisms, and prevention and treatment measures. The purpose was to help clinicians better understand and accurately diagnose VIPN, select appropriate intervention measures and reduce the damage to cancer patients.

Alterations of drug-metabolizing enzymes and transporters under diabetic conditions: what is the potential clinical significance?

There will be 642 million people worldwide by 2040 suffering from diabetes mellitus. Long-term multidrug therapy aims to achieve normal glycemia and minimize complications, and avoid severe hypoglycemic events. The appreciation of the drug-metabolizing enzymes and drug transporters as critical players in the treatment of diabetes has attracted much attention regarding their potential alterations in the pathogenesis of the disease. This review discusses pharmacokinetics-based alterations of cytochrome P450 enzymes, phase-II metabolizing enzymes, and membrane transporter proteins, as well as the potential mechanisms underlying these alterations. We also discuss the potential influences of altered enzymes and transporters on the disposition of commonly prescribed glucose-lowering medicines. Future studies should delve into the impact of altered drug-metabolizing enzymes and transporters on the progression toward abnormal glucose homeostasis.

[Analysis of typical mangrove spectral reflectance characteristics].

Acquisition of mangrove spectrum properties and detecting the sensitive bands provide technology basis for inverse modeling and estimation by remote sensing for various indexes of mangrove. The typical mangroves of Guangxi Shankou Mangrove Reserve were taken for study objects, the standard spectrum curves of Bruguiera gymnorrhiza (Linn.) Savigny, Rhizophora stylosa, Kandelia candel, Avicennia marina, Aegiceras corniculatum, Spartina anglica and mudflat were gained by denoising analysis of field-measured spectrum curves acquired by ASD FieldSpec 2. Analyzing the spectral characteristics and their differences, the authors found that the spectrum curves for various kinds of mangrove are coincident, the bands that appeared with reflection peaks and reflection valleys are basically identical, the within-class differentiated characteristics are comparatively small, the spectrum characteristics of mangroves are obviously different with Spartina anglica and mudflat. In order to gain the quantitative description for within-class differentiated characteristics of mangrove, space distance method, correlation coefficient method and spectral angle mapping method were used to calculate the within-class differentiated characteristics. The division accuracy of correlation coefficient method is higher than spectral angle mapping method which is higher than space distance method, and the result indicates that the spectrum differences of within-class mangrove and Spartina anglica are relatively small with correlation coefficients more than 0.995, and spectrum curve angle cosine values more than 0.95.

Synthesis and luminescent properties of novel BaGd2O4:Eu3+ scintillating phosphor.

BaGd2-x O4:xEu(3+) and Ba1-y Gd1.79-2y Eu0.21 Na3y O4 phosphors were synthesized at 1300°C in air by conventional solid-state reaction method. Phosphors were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence excitation (PLE) spectra, photoluminescence (PL) spectra and thermoluminescence (TL) spectra. Optimal PL intensity for BaGd2-x O4 :xEu(3+) and Ba1-y Gd1.79-2y Eu0.21 Na3y O4 phosphors at 276 nm excitation were found to be x = 0.24 and y = 0.125, respectively. The PL intensity of Eu(3+) emission could only be enhanced by 1.3 times with incorporation of Na(+) into the BaGd2 O4 host. Enhanced luminescence was attributed to the flux effect of Na(+) ions. However, when BaGd2 O4:Eu(3+) phosphors were codoped with Na(+) ions, the induced defects confirmed by TL spectra impaired the emission intensity of Eu(3+) ions.

Effects of hyperbaric oxygen on aggressive periodontitis and subgingival anaerobes in Chinese patients.

OBJECTIVE: To investigate the effects of hyperbaric oxygen (HBO2) on aggressive periodontitis (AgP), and subgingival obligate anaerobes in Chinese patients. MATERIALS AND METHODS: Sixty cases of Chinese patients with AgP were randomly divided into two groups -the HBO2 group (30 cases) and the control group (30 cases). Study teeth were divided into four groups -: the HBO2 therapy, the HBO2 + scaling scaling group, the scaling group and the control group. Subgingival anaerobic organisms were measured with anaerobic culture, and number of obligate anaerobes and facultative anaerobes and Bacteroides melaninogenicus was counted. Comparisons of changes in the clinical indices, and subgingival anaerobes were made between the groups. RESULTS: Highly significant differences in gingival index (GI), probing depth (PD), attachment loss (AL), and Plaque index (PLI), and tooth odontoseisis (TO) were seen in the HBO2, the HBO2 + scaling and the scaling groups when compared with the control group (P<0.01). The number of subgingival anaerobes as well as the types of obligate anaerobes and facultative anaerobes and the number of Bacteroides melaninogenicus were reduced markedly in these three treatment groups. Highly statistical differences in clinical indices, subgingival anaerobe number and types of obligate anaerobes and facultative anaerobes and Bacteroides melaninogenicus were found when comparisons were made between the HBO2 + scaling and the HBO2 groups, as well as between the HBO2 + scaling and the scaling groups. Clinical follow-ups indicated that the GI, PD, AL, TO, PLI and subgingival anaerobes number of the three therapeutic groups were reduced more severely than the control group. CONCLUSIONS: HBO2 had good therapeutic effects on Chinese patients with AgP. HBO2 therapy combined with scaling and root planing was the most beneficial in the treatment of AgP. The therapeutic effect of HBO2 on AgP is most likely through inhibition of the growth of subgingival anaerobes. Clinical follow-ups suggest that the effect could last more than 2 years.

[Teaching reform in oral biology by course integration].

In order to adapt to the needs of development of higher stomatological education,Shanghai Jiao Tong University College of Stomatology sets a new fundimental course "Oral Biology" in 2001. This subject integrates the basic medical courses and the clinical medical courses. It contains broad subjects,wide knowledge and novel contents. Recently teaching reform of curriculum integration has consolidates and extends the previous knowledge,and impels the amalgamation of teaching content and course system. This method has achieved significant success and is worth of generalization.

[Biological characteristic comparison between long junctional epithelium cells and junctional epithelium cells].

PURPOSE: To culture long junctional epithelium (LJE) cells in vitro and compare its biological characteristics with junctional epithelium (JE) cells. METHODS: LJE samples were collected from the patients with chronic periodontitis during flap surgery. Sulcular parts of tissues were removed by sterile scissor then enzymatic method and keratinocyte-serum free medium (KSFM) were used for culturing. JE samples were obtained from healthy bicuspid premolars or third morlars for orthodontic or impaction reasons and the cells were cultured in the same way as LJE. The two types of cells were compared in cell morphology, dimension,viability, proliferation, apoptosis and cytokeratin expression by means of cytoanalyzer, confocal laser scanning microscope and flowcytometry. Statistical analysis was performed using SPSS11.5 software package for independent-samples t test. RESULTS: LJE and JE cells exhibited similar cell morphology. Although the viability of LJE cells were lower than JE cells, there were no statistical significance (P>0.05). The mean diameter and volume of LJE cells were (19.03+/-0.19)microm and (4.29+/-0.19)x10(3) fL versus (17.16+/-0.95)microm and (3.20+/-0.52)x10(3)fL of JE cells (P<0.05). The doubling time of LJE cells, was longer than that of JE cells.CK19 expression of LJE cells was weaker than of JE cells and there were no difference in the expression pattern of CK6 and CK13. Compared with control cells, the early- and late-stage apoptosis ratio of LJE cells were (4.62+/-2.16)% and (9.46+/-1.84)%, respectively which were all higher than JE cells which were (0.47+/-0.63)% and (3.84+/-0.98)% (P<0.05). CONCLUSION: There is difference between LJE and JE cells in dimension, CK19 expression, proliferation time and apoptosis. This study provides some clinical significance and aid in understanding the biological characteristics of LJE and the healing process of periodontitis.

[Comparison of the attachment and growth characteristics between human junctional epithelium and oral epithelium cells].

OBJECTIVE: To compare the attachment and growth characteristics between human junctional epithelium (JE) and oral epithelium cells. METHODS: The healthy JE biopsies were derived from the human teeth extracted due to impaction or orthodontic purpose. Enzyme digestion was used to isolate JE cells, which were then cultured in DKGM. The co-culture model of JE cell-tooth slice was built up by adding 3 decalcification cementum slices (5 mm x 3 mm x 1 mm) into sterilized plate containing 1 ml of JE cells (5 x 10(8)/L), 21 slices all together,and incubated in an atmosphere containing 5% CO2 at 37 degrees C for 1-14 days. The attachment structure was observed under transmission electron microscope, and the OE cells was used as control. RESULTS: The human JE cells were polymorphous in shape and CK19 positive, while OE cells were consisted of equal and closely packed epithelial-like cells in a paving stone arrangement, and CK19 was only strained in a few cells. There were a few cells in JE-slice when co-cultured for 1-3 days, and electron dense plaques on the JE cell surface of the attached slice were observed at 9 days, and 2-3 layer of JE cells and hemidesmosome-like structure formed within 11-14 days. There were more OE cells within 1-3 days, electron dense plaques appeared at 7 days, and stratified epithelium and hemidesmosome-like structure formed in OE-slice at 9 days. CONCLUSIONS: The cultured JE cells were immature and lower differentiated epithelial cells which were different from OE cells. Under the same condition the growth and attachment of JE cells on the cementum slice surface were slower than that of OE cells. Their attachment strength needs further study.

[The effects of epidermal growth factor on the wound repair of junctional epithelial cells and gingival epithelial cells in vitro].

PURPOSE: To study the effects of epidermal growth factor (EGF) on the proliferation and cellular fill of junctional epithelium (JE) and gingival epithelium (GE) by using an in vitro wound model. METHODS: EGFR mRNA was semiquantitatively determined by reverse transcriptase polymerase chain reaction (RT-PCR) and immunocytochemistry was performed to measure EGFR expression. JE and GE cells were plated into 6 well tissue culture plates containing 22mm x 26mm sterile glass coverslips. After cells were grown to confluence, a 3mm wide wound was created at the center of the coverslips. The cells were incubated in medium containing EGF at a 20ng/mL concentration. Negative controls were incubated in keratinocyte serum-free medium. At 5, 9 and 12 days following wounding, the coverslips were removed and stained with hematoxylin and eosin (HE) and proliferating cell nuclear antigen (PCNA). Quantification of percentage of cellular wound fill and PCNA positive nuclei was accomplished by using computer assisted histomorphometry.The data were analyzed with SAS6.12 software package. RESULTS: Densitometric scanning indicated that EGFR mRNA expression in GE cells was 1.2-fold higher than that in JE cells. EGFR protein was positive in GE and JE immunocytochemically. At 9 -day post-wounding, GE and JE demonstrated significantly greater proliferative responses to EGF when compared to negative controls (P<0.05). But there were no significant differences in the proliferative responses to EGF between the two cell types (P>0.05). At each time point, EGF stimulated the cellular fill of JE and GE compared with negative controls (P<0.05). However, GE displayed greater cellular fill significantly than JE at day 9 and 12 post-wounding (P<0.05). CONCLUSIONS: EGFR is present in the JE and GE cells. EGF may regulate the cell fill and proliferation of the two cell types in this in vitro model.

[The modification of culture and cryopreservation methods for human junctional epithelium cells].

PURPOSE: To study the methods for isolating, culturing and cryopreserving junctional epithelium(JE) cells. METHODS: JE tissue samples were obtained from human periodontally healthy premolars which were extracted for orthodontic reasons. The sulcular epithelium was removed at a distance of 1 mm from the gingival margin. JE tissue was detached from the extracted teeth by using 11 sterile blade and minced into small fragments. The cultured JE cells were incubated with a freezing medium consisting of 90% calf serum and 10% DMSO. The freezing protocol was applied using a computer-controlled freezer to freeze the medium to -80 degrees centigrade before cells were plunged into liquid nitrogen and stored. The above procedures were optimized to further study the morphology, proliferation, determination of JE cells and measure the viability after thawing. RESULTS: 0.1% trypsin containing 0.02% ethylenediamine tetraacetate (EDTA) digestion was used to isolate JE cells successfully without dispase. The viability of thawing JE cells was(93.87+/-3.11)%, and the morphology was similar to that of the second passage JE cells. CK19 and vimentin were both positive in JE cells immunocytochemically. CONCLUSION: The methods could be applied into practice. The phenotype of JE cells in vitro is not always consistent with that in vivo. It might be associated with the substrate which cells grow in contact with.

[Effects of garlic on oral bacteriostasis and root detoxification].

PURPOSE: To evaluate the pharmacologic effect of garlic on oral bacteriostasis and root detoxification. METHODS: Eight representative oral anaerobes (58 strains) including Streptococcus (9), Peptococcus (4), Lactobacillus (6), Actinomyces (3), Veillonella (10), Porphyromonas (12), Prevatella (3), Fusobacterium (11) to garlic juice were systematically studied by classical tube susceptibility test. The periodontally involved roots (12) were selected and the slices (6 mm x 3 mm x 1 mm) were prepared on the exposed root surface. Six slices were randomly treated by garlic juice for 5 minutes; the other six slices were treated by normal saline with same method as control. The attachment of cultured L-fibroblasts to the treated root surface was observed under phase contrast microscope and electron scanning microscope. The attachment cells were statistically analyzed using SPSS10.0 software package for Student's t test. RESULTS: The minimal inhibitory concentration of garlic juice on most oral anaerobes (87.93%) was 1:64-1:512. The attachment L-fibroblasts to the garlic treated group increased significantly vs. the control group (P<0.05). CONCLUSION: The study shows that garlic juice could effectively inhibit oral anaerobes and reestablish the root biological adaptation.

[Cytokeratin expression in human junctional epithelium, oral epithelium and sulcular epithelium].

OBJECTIVE: To investigate the expression of cytokeratins (CK) in the normal human gingival epithelium and to explore the difference between junctional epithelium (JE), oral epithelium (OE) and sulcular epithelium (SE). METHODS: Teeth specimens with gingival tissue were collected from 5 people. Paraffin-embedded sections were stained with monoclonal antibodies responded respectively to human CK5/6, 7, 8/18, 10/13, 16, 17, 19, 20. RESULTS: CK7 and 17 was not expressed in all strata of JE, OE and SE. CK5/6 and 20 were weekly or moderately expressed in the suprabasal, and not expressed in the basal layer of all three epithelia. CK10/13 and 16 were positive in all strata of JE and in the suprabasal layers of OE and SE. CK10/13 was moderately to strongly expressed and CK16 was weekly to moderately expressed. The staining for CK19 was intense in all strata of JE and the basal layer of OE and SE. There was a remarkable demarcation between JE and SE. The pattern of CK8/18 expression was similar to that of CK19, but was weaker. Besides the basal layer, some suprabasal layers close to the basal layer were stained. CONCLUSIONS: JE is an unique non-differentiated stratified epithelium different from OE and SE. CK19 would be a histological marker and CK10/13, 16 would be the cellular markers to differentiate JE from OE and SE.

[Clinical survey of the association between stress and periodontitis].

PURPOSE: To investigate the effects of stress on periodontitis. METHODS: 44 chronic periodontitis patients and 42 patients with healthy periodontal tissues(as control) were enrolled in the study. All subjects were required to complete a questionnaire which was mainly made up of the symptom checklist 90. Data collected included clinic parameters, psychological factors, life events and basic socio-demographics. The results were statistically assessed by SPSS 10.0 software. RESULTS: There was significant difference between periodontitis group and the control group in education, marital status, and life events (P<0.05 or P<0.01). Compared with the controls, the periodontitis patients got higher scores in somatization, obsessive-compulsive, interpersonal sensitivity, depression, anxiety, hostility, the impact of sleep and diet (P<0.05 or P<0.01). In periodontitis group, there was significant correlation between CPITN, CI and depression, anxiety, interpersonal sensitivity, etc. (P<0.01 or P<0.05). CONCLUSIONS: In this sample, there was a close association between stress and periodontitis. Stress may be a significant risk indicator for periodontitis.

[Culture and comparison of the biological characteristics of human junctional epithelium and gingival epithelium].

PURPOSE: To study the different biological characteristics of human junctional epithelium (JE) and gingival epithelium (GE). METHODS: Human JE cells were cultured and identified by the cell culture and immunohistochemistry, and the biological characteristics of JE cells and GE cells were compared. RESULTS: The morphology of cultured JE cells was various and unequal, the arrangement of the cells was loose and mitosis was common, while GE colony was consisted of equal and closely packed epithelial-like cells in a paving stone arrangement. CK-Pan staining was positive in all JE and GE cells. CK19 was strongly stained in all JE cells but only moderately stained in some GE cells, and most GE cells were negative which was obviously different from JE cells. JE cells had longer latent period (7 days) than GE cells (4 days) during the cell growth period, and then the cells proliferated rapidly (4 days) to attain the maximum and descended rapidly in the declining period. While GE cells ascended evenly (7 days) to attain the maximum and descended slowly in the declining period. Proliferation study demonstrated the doubling time of JE cells was 48 to 60 hours and that of GE cells was 72 to 96 hours. It was possible to subculture JE cells up to 5 times serially, and that of GE cells was up to 7 times. CONCLUSIONS: The human JE cells are a kind of unique non-differentiated epithelial cells different from GE cells. In this experimental culture condition the subculture times of JE cells were less than GE cells, which affects JE cells, so the culture methods and conditions should be improved.

[Isolation, culture and identification of mouse dental follicle cells and their heterogeneity].

PURPOSE: To establish a method for isolation and culturing mouse dental follicle cells and to identify its origin; meanwhile, the biological characteristics were detected. METHODS: Mandibular first molars from 7-day-old Balb/c mice were digested with 1% trypsin; subsequently, the dental follicle was enucleated from the tooth germ and cultured. Vimentin and cytokeratin were examined to identify its origin. The shape of dental follicle cells were observed by HE staining. Gomori modified calcium-cobalt staining method was used to examine alkaline phosphatase (ALPase) activity of dental follicle cells. Immunocytochemistry was used to detect the expression of collagen type I and osteocalcin (OCN). RESULTS: The isolated cells were pleomorphism and there were three basic types of cells: some were cuboidal/polygonal; some were elongated, spindle-shaped, fibroblast-like cells; a minor, third cell type was very thin and elongated. 2 or 4 nucleoli were within each nucleus.The cytoplasm of the first two cell types was filled with abundant granules and the cells had many filipodia. The expression of vimentin was positive while that of the cytokeratin was negative. Some but not all follicle cells expressed ALPase, collagen type I and OCN. CONCLUSION: The cultured dental follicle cells were originated from mesenchyme, consisted of several cell phenotypes and were heterogeneous.

[Comparative study on the histomorphology of the JE of human and several laboratory animals].

PURPOSE: To investigate the histomorphology of the junctional epithelium (JE) of human and several animals, and determine the suitable laboratory animals, position and methods for JE study. METHODS: Paraffin-embedded bucco-lingual sections of mandible molars with gingival tissue from 6 men, 3 pigs, 4 dogs, 6 rabbits and 6 rats were stained by HE and analyzed by image analysis system. RESULTS: The width of JE of human, pig, dog, rabbit and rat was (1.019+/-0.133) mm, (0.862+/-0.073) mm, (1.111+/-0.104) mm, (0.404+/-0.010) mm and (0.285+/-0.032) mm, respectively, and the ratio of the width of JE to the gingival sulcular epithelium (GSE) and JE was about 60%. The histology and morphology of JE of pig and dog were similar to that of human, the epithelium was long, thin, regular and connected with GSE. The demarcation between JE and GSE was judged by the differences in the cytology and staining. The JE of rabbit and rat was irregular and quite different from that of human. It was located on the surface of GSE, turned wide towards its bottom and the top of it was separated from GSE which was remarkably keratinized. CONCLUSIONS: The most suitable animals for JE study are pig and dog because of their similarity to human on the morphology and development of JE. The mastery of the anatomical and physiological characteristics of JE of human and several laboratory animals and determination of the suitable objects would provide useful data and methods for further study of the biological and molecular characters of JE cells.

[Study on odontal & periodontal tissue of guinea pigs, dogs and monkeys].

PURPOSE: To evaluate the different application of different experimental animals in studies of periodontal diseases. METHODS: The odontal and the periodontal tissues of guinea pigs, dogs and monkeys were studied by gross specimen, X ray and histological observation. RESULTS: The most suitable sites of guinea pigs for periodontal study is incisor just because of their small oral fissure, but the keratinized epithelium of gingival sulcus may affect their inflammatory reaction. As the occurring of spaces from the 3rd to 5th tooth of dogs, artificial intrabony pocket can be made, and their thick root canals are suitable for pulp and periapical study. The monkeys are the ideal experimental animals due to their similarities to human, but it is too expensive to be widely used. CONCLUSION: Each kind of animal has their own characteristics. The key is to select experimental animal according to the objective of our different studies.

[Dynamic observation of periodontal pathogens and cariogenic bacteria in modified chemostat using confocal laser scanning microscopy].

OBJECTIVE: To study dynamic relation between periodontal pathogens and cariogenic bacteria under analogous oral environment. METHODS: Eight periodontopathic and cariogenic bacteria of Porphyromonas gingivalis (Pg), Actinobacillus actinomycetemcomitans (Aa), Fusobacterium nucleatum (Fn), Provotella intermedium (Pi), Streptococcus mutans (Sm), Streptococcus sanguis (Ss), Actinomyces viscosus (Av) and Lactobacillus acidophilus (La) were used. These eight strains were cultured in modified chemostat under analogous oral environment which contained 600 ml modified BM medium supplemented with 2.5 g/L porcine gastric mucin, respectively. After 1, 24, 48 and 96 h, optical sectioning of plaque biofilms on removable and replaceable hydroxyapatite disks was analyzed by the combination of live bacterial Gram fluorescence staining and confocal laser scanning microscopy. Biofilm thickness and reconstruction of the three-dimensional architecture of plaque biofilms were made. RESULTS: Biofilm thickness increased significantly with time (P < 0.001). Biofilms of Aa were thinner than those of Ss and eight-specie biofilms were thicker than those formed by Ss and Aa per time point. Three-dimensional images showed periodontal pathogens mainly occurred in cariogenic bacterial complex or on the biofilm surface. CONCLUSIONS: Gram-positive cariogenic species initially predominated in artificial plaque, followed by the increasing proportions of Gram-negative periodontal pathogens. The relation between microecological balance among bacteria and diseases is worthy of further studies.