Biomedical subjects

Tao He

Publications and source records attributed to Tao He.

At least 37 records · Page 2Linked to original sources

PubMed2005

Poly(ethylene glycol) micro-patterns as environmentally sensitive template for selective or non-selective adsorption.

Poly(ethylene glycol) (PEG), a hydrophilic and repulsive polymer to non-specific adsorption, was stamped onto carboxylic acid-enriched polymer surfaces using the micro-contact printing technique. The patterns are stabilized via hydrogen bonds. Areas printed with PEG were then shown to be non-adsorbed with fluorescein isothiocyanate (FITC)-labeled dextran, while the poly(methacrylic acid) (PMAA) regions could via hydrogen bonding. Due to this contrast, well defined dextran patterns were obtained. Tuned with pH and temperature, the PEG molecules could be detached from the surfaces, erasing the template. Moreover, ionization of PMAA at higher pH induced an abrupt transition to an extended conformation, weakening the interactions between PMAA and dextran. Not only the dextran patterns lose their spatial selectivity, but also the overall adsorption amount is much lower. The pH sensitivity was in a quite narrow range, i.e. around pH 5. As the hydrogen bonds are also temperature sensitive, the attach points of PEG molecules on the surfaces disappeared at higher temperature. For poly(acrylic acid) (PAA) photografted surfaces, the pH sensitivity was more complicated due to the formation of the compact complexes of PEG and PAA molecules.

Adsorption↗

PubMed2005

Surface modification of poly(ethylene terephthalate) via hydrolysis and layer-by-layer assembly of chitosan and chondroitin sulfate to construct cytocompatible layer for human endothelial cells.

Surface modification of poly(ethylene terephthalate) (PET) film was performed by surface hydrolysis and layer-by-layer (LBL) assembly followed a mechanism of electrostatic adsorption of oppositely charged polymers, exemplified with chitosan and chondroitin sulfate (CS). Hydrolysis of PET in concentrated alkaline solution produced a carboxyl-enriched surface. The changes of weight loss and surface chemistry, morphology and wettability were monitored and verified by UV-vis spectroscopy, atomic force microscopy (AFM) and water contact angle. Assembly of positively charged chitosan and negatively charged CS was then conducted in a LBL manner to create multilayers on the hydrolyzed PET film. The process of layer growth and oscillation of surface wettability were monitored by UV-vis spectroscopy and water contact angle measurement, respectively. In vitro cell culture revealed that the adherence of endothelial cells was significantly enhanced on the biomacromolecules-modified PET film with preserved endothelial cell function, in particular on those assembled with larger number of chitosan/CS layers. However, with regard to cell proliferation and viability properties after cultured for 4 days, minor difference was determined between the modified and the unmodified PET films.

Adsorption↗

PubMed2005

Identification of bacteria with beta-galactosidase activity in faeces from lactase non-persistent subjects.

Previous studies suggest that, besides the maldigestion of lactose in the small intestine, the colonic processing of lactose might play a role in lactose intolerance. beta-Galactosidase is the bacterial enzyme which catalyzes the first step of lactose fermentation in the colon. We propose a practical method to differentiate and identify bacteria with beta-galactosidase activity in faeces which combines a colony-lift filter assay with X-gal (5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside) as substrate for differentiation and the fluorescent in situ hybridization technique for identification. The method was applied to faeces from lactase non-persistent subjects. After 28 subjects had undergone one glucose and two lactose challenges, consistent intolerant (n=5) and tolerant (n=7) groups were defined according to their symptom scores. Of the 28 faecal samples, 80.6% (mean, SD: 12.1, range: 47.8-100%) of the total cultured bacteria were found to possess beta-galactosidase activity, which indicates that the bacterial beta-galactosidase is abundant in the colon. The tolerant and intolerant groups did not differ in the percentage or composition of the bacteria with beta-galactosidase activity or beta-galactosidase activity in faeces. Results suggest that the percentage or composition of the bacteria with beta-galactosidase activity in faeces do not play a role in lactose intolerance.

Adult↗

PubMed2005

MicroRNA identification based on sequence and structure alignment.

MOTIVATION: MicroRNAs (miRNA) are approximately 22 nt long non-coding RNAs that are derived from larger hairpin RNA precursors and play important regulatory roles in both animals and plants. The short length of the miRNA sequences and relatively low conservation of pre-miRNA sequences restrict the conventional sequence-alignment-based methods to finding only relatively close homologs. On the other hand, it has been reported that miRNA genes are more conserved in the secondary structure rather than in primary sequences. Therefore, secondary structural features should be more fully exploited in the homologue search for new miRNA genes. RESULTS: In this paper, we present a novel genome-wide computational approach to detect miRNAs in animals based on both sequence and structure alignment. Experiments show this approach has higher sensitivity and comparable specificity than other reported homologue searching methods. We applied this method on Anopheles gambiae and detected 59 new miRNA genes. AVAILABILITY: This program is available at http://bioinfo.au.tsinghua.edu.cn/miralign. SUPPLEMENTARY INFORMATION: Supplementary information is available at http://bioinfo.au.tsinghua.edu.cn/miralign/supplementary.htm.

Algorithms↗

PubMed2005

Differences in platelet endothelial cell adhesion molecule-1 expression between peripheral circulation and pancreatic microcirculation in cerulein-induced acute edematous pancreatitis.

AIM: To investigate the changes of platelet endothelial cell adhesion molecule-1 (PECAM-1) expression on polymorphonuclear leukocytes (PMNs) in peripheral circulation and pancreatic microcirculation in cerulein-induced acute edematous pancreatitis (AEP). METHODS: Fifty Wistar rats were randomly divided into control group (n = 10) and AEP group (n = 40). A model of AEP was established by subcutaneous injection of cerulein 5.5 and 7.5 mug/kg at 0 and 1 h after the beginning of experiment respectively. PECAM-1 expression on PMNs from splenic vein and inferior vena cava was determined by RT-PCR at mRNA level and determined by flow cytometry at protein level. RESULTS: In experimental rats, an increased PECAM-1 mRNA expression was seen from 4 to 8 h of AEP in peripheral circulation (0.77+/-0.25%, 0.76+/-0.28%, 0.89+/-0.30%, 1.00+/-0.21%), while in pancreatic microcirculation, expression decreased from 2 h and reached the lowest level at 6 h of AEP (0.78+/-0.29%, 0.75+/-0.26%, 0.62+/-0.28%, 0.66+/-0.20%). There were significant differences at 8-h time point of AEP between peripheral circulation and pancreatic microcirculation (1.00+/-0.21% vs 0.66+/-0.20%, P<0.05). Meanwhile, the difference at protein level was also found. CONCLUSION: A reverse expression of PECAM-1 on PMNs was found between peripheral circulation and pancreatic microcirculation, suggesting that inhibition of PECAM-1 expression may improve the pathological change of AEP.

Acute Disease↗

PubMed2005

Anti-gingivitis efficacy of a stabilized 0.454% stannous fluoride/sodium hexametaphosphate dentifrice.

OBJECTIVE: Stannous fluoride is a broad-spectrum anti-microbial agent that has been used in dentistry as a chemical adjunct to prevent dental caries and gingivitis. The objective of this study was to assess the anti-gingivitis efficacy of a stabilized 0.454% stannous fluoride/sodium hexametaphosphate dentifrice relative to a negative control. METHODS: This was a randomized, 6-month, double-blind, parallel-group gingivitis study conducted according to the guidelines for evaluating chemotherapeutic products for the control of gingivitis outlined by the American Dental Association. A stabilized 0.454% stannous fluoride/sodium hexametaphosphate dentifrice was tested against a commercially available negative control dentifrice. Following baseline measurements, subjects received a dental prophylaxis. Subjects were then instructed to brush twice daily for 60 s using their assigned product. Oral soft-hard-tissue examinations and clinical examinations using the Modified Gingival Index, Gingival Bleeding Index, and the Turesky modification of the Quigley-Hein Plaque Index were performed at baseline, 3 and 6 months post-treatment. RESULTS: A total of 143 subjects were enrolled and 130 of them completed the 6-month study. After 6 months of product usage, the experimental group had 21.7% less gingivitis (p<0.001), 57.1% less bleeding (p<0.001), and 6.9% less plaque (p=0.01) on average compared with the negative control group. No adverse oral soft-hard-tissue effects or extrinsic tooth staining was observed in the study. CONCLUSION: The results demonstrate that use of the stabilized 0.454% stannous fluoride/sodium hexametaphosphate dentifrice over a 6-month period provided statistically significant reductions in gingivitis, gingival bleeding, and plaque when compared with a negative control dentifrice.

Adolescent↗

PubMed2005

[IGFBP-2 mRNA expression in gastric cancer tissues and its roles in proliferation, differentiation and peritoneal metastasis of gastric cancer].

OBJECTIVE: To detect the expression of IGFBP-2 mRNA in gastric cancer tissues and its roles in neoplasia and peritoneal metastasis of gastric cancer. METHODS: The IGFBP-2 mRNA expression levels in the fresh tissues from normal mucosa, primary cancer and peritoneal metastasis of 35 patients with gastric cancer were determined by the quantitative real time RT-PCR method, and the samples were sliced up and stained with hematoxylin-eosin for pathologyical examination. RESULTS: The levels of IGFBP-2 mRNA expression in gastric primary cancer tissues were significantly higher than those in the tissues from normal mucosa and peritoneal metastasis (P<0.05). Yet, IGFBP-2 mRNA expression levels showed no difference between the tissues of normal mucosa and peritoneal metastasis (P>0.05). CONCLUSION: The expression of IGFBP-2 mRNA possibly plays an important role in proliferation, differentiation and peritoneal metastasis of gastric cancer, and it might be useful in a new method for clinical prognostication and treatment of gastric cancer peritoneal metastasis.

Adult↗

PubMed2005

[Fracture resistence force of the cement-expanded composite screw post-core system].

OBJECTIVE: This is a study comparing the effects of different post designs on the fracture resistence. METHODS: Twenty-seven simulated tooth roots made of polymethyl methacrylate (PMMA) were divided into three groups, then the cement-expanded composite screw post-core system (CECSP), cement screw post-core system (CSP) and cast metal post-core system (CMP) were manufactured. The root and post-core system was compressed by the speed of 1 mm/min on the Instron 4302 and the fracture resistence force was recorded. RESULTS: Statistical analysis of the measured values showed the fracture resistence force of CECSP and CMP to be significantly greater than that of CSP (P < 0.05), but there was no significant difference between the fracture resistence force of CECSP and CMP (P > 0.05). CONCLUSION: The fracture mechanical properties of CECSP are much better than those of cement screw post-core system and are similar to cast metal post-core system. Therefore, it is possible to find a new way for restoration of endodontally treated teeth.

Composite Resins↗

PubMed2005

[Study on association between the expression of galectin- 3 and the peritoneal metastasis in gastric cancer].

OBJECTIVE: To investigate the association between the expression of galectin- 3 protein and peritoneal metastasis in gastric cancer. METHOD: The expressions of galectin- 3 was detected in matching- samples including primary gastric cancer lesions,lymph node metastases,peritoneal metastases and paratumor normal tissues by immunohistochemistry. All specimens were gained from 35 patients who had synchronous peritoneal metastasis from gastric cancer. RESULTS: The over- expression of galectin- 3 was observed in 97% (34/35) of the gastric cancer lesions, the peritoneal metastases and the lymph node metastases,whereas in 14% (5/35) of paratumor normal tissues. There were significant differences in the expression of galectin- 3 between paratumor normal tissues and the gastric carcinoma lesions,peritoneal metastases and lymph node metastases (P< 0.05),but there were no significant differences among the gastric cancer lesions,the peritoneal metastases,and the lymph node metastases (P> 0.05). CONCLUSION: The expression of galectin- 3 in gastric cancer lesions can be used as a biological marker of peritoneal metastasis from gastric cancer before operation and as a prognostic factor of gastric cancer.

Galectin 3↗

PubMed2005

A 6-month clinical trial to study the effects of a cetylpyridinium chloride mouthrinse on gingivitis and plaque.

PURPOSE: To evaluate the effects of a novel mouthrinse containing 0.07% high bioavailable cetylpyridinium chloride (Crest Pro-Health Rinse) on the development of gingivitis and plaque versus a placebo control over a period of 6 months. METHODS: This was a randomized, 6-month, placebo-controlled, parallel groups, double blind, single center clinical trial. One hundred thirty-nine generally healthy adults with mild-to-moderate gingivitis were enrolled in the study. Subjects were given Modified Gingival Index (MGI), Gingival Bleeding Index (GBI) and Modified Quigley-Hein Plaque Index (MQH) examinations followed by a dental prophylaxis. Subjects were then randomly assigned to either the cetylpyridinium chloride (CPC) rinse or placebo rinse and instructed to begin rinsing twice a day with 20 ml of their assigned mouthrinse for 30 seconds after brushing their teeth. Subjects were assessed for MGI, GBI and MQH scores after 3 and 6 months of product use. Oral hard and soft tissue examinations were also performed at all visits. RESULTS: 124 subjects were evaluable at Month 3 and 119 at Month 6. After 6 months, subjects rinsing with the CPC rinse showed 15.4% less gingival inflammation, 33.3% less gingival bleeding, and 15.8% less plaque relative to the placebo group. All reductions were highly statistically significantly different (P< 0.01). Results were similar at 3 months. Both treatments were well-tolerated. CLINICAL SIGNIFICANCE: This study demonstrates that the Crest Pro-Health 0.07% CPC mouthrinse provided significant antiplaque and antigingivitis benefits when used twice daily for 6 months as an adjunct to toothbrushing.

Adolescent↗

PubMed2005

[Effects of expansion fashion and expansion quantity on retention of cement-expanded composite screw post].

OBJECTIVE: To study the effects of expansion fashion and expansion quantity on retention of cement-expanded composition screw post (CECSP). METHODS: Ninety simulated tooth roots made of polymethylmethacrylate were divided into ten groups, each fashion induded five groups. The expanded plastic sheath of tricuspid valve was made with the special separated valve device and cemented and tightened up into root with the screw post at the same time by ZPC. Then the root and screw post-core system was tested by the speed of 10 mm/min on the INSTRON 4302 and the retention force was recorded. RESULTS: It appeared that the difference between different expansion fashion and different expansion quantity were significantly (P < 0.05). The retention of expansion fashion one was significantly greater than those of fashion two. The retention was best when expansion quantity was within 10%. CONCLUSION: During clinic operation, we should apply definite fashion and control the expansion quantity within 10%, and the screw post should tighten up to the bottom of prepared root.

Bone Screws↗

PubMed2005

The inhibitory effect of quercetin on IL-6 production by LPS-stimulated neutrophils.

Quercetin is a herbal flavonoid derived from various foods of plant origin and plays a role in anti-inflammation. Although a number of researches in the field have been done, the mechanism of anti-inflammatory effect of quercetin should be further clarified. In the present study, we investigated the effects of quercetin on IL-6 production by LPS-stimulated neutrophils in human. Neutrophils were were pre-treated with quercetin at the final concentrations of ranging from 0-80 microM for 30 min, or not treated, and then incubated in the presence or absence of lipopolysaccharide (LPS) at a final concentration of 100 ng/ml for indicated time. The secretion level of IL-6 in the culture supernatants was assayed by ELISA, the intracellular level of IL-6 was detected by flow cytometry and the expression of IL-6 mRNA was analyzed by RT-PCR. The experiment results showed that neutrophils cultured with medium or quercetin alone did not express IL-6, but LPS (100 ng/ml) induced IL-6 expression of neutrophils. However, after pre-treatment of neutrophils with quercetin (40 microM) for 30 min, the inducible effects of LPS on the increase of IL-6 secretion, intracellular IL-6 level and IL-6 mRNA expression by neutrophils were abrogated. IL-6 is one of the important pro-inflammatory factors, especially in early phage of inflammation. Thus, our data suggested that quercetin might exert its anti-inflammatory effect through negatively modulating pro-inflammatory factors, such as IL-6. The inhibitory effects of quercetin on IL-6 production by neutrophils may provide a theoretical basis on future therapy of inflammation.

Cells, Cultured↗

PubMed2005

A novel dentifrice technology for advanced oral health protection: A review of technical and clinical data.

Throughout the world, dentifrices have played a key role in the practice of good oral hygiene and promotion of better oral health. In addition to providing general dental cleaning, toothpastes also have served as an excellent vehicle for the introduction of new agents that deliver therapeutic and cosmetic benefits. Key examples of using dentifrices to provide added benefits include the introduction in 1955 of the first fluoridated toothpaste clinically proven to fight caries (Crest Cavity Protection) and the launch of the first tartar-control dentifrice (Crest Tartar Control) in the mid-1980s. To continue expanding the health and esthetic benefits offered by a single dentifrice, a multitude of agents have been investigated over the past 3 decades. The focus of these investigations has been in the multibenefit segment, the most widely used among US consumers.

Anti-Bacterial Agents↗

PubMed2005

Antigingivitis efficacy of a stabilized stannous fluoride/sodium hexametaphosphate dentifrice in subjects previously nonresponsive to a triclosan/copolymer dentifrice.

Antimicrobial agents, such as stannous fluoride and triclosan, have been incorporated into dentifrice formulations and shown to be effective in the prevention and reduction of gingivitis. However, not all subjects respond to treatment. The objective of this study was to assess the antigingivitis efficacy of a 0.454% stannous fluoride/sodium hexametaphosphate dentifrice among subjects who were identified as nonresponsive or minimally responsive to a sodium fluoride/triclosan/copolymer dentifrice. This was a 12-week, examiner-blind, single-center study. Forty-one subjects with no or minimal gingivitis response to 6 months of use of a sodium fluoride/triclosan/copolymer dentifrice were enrolled in this study and 38 of them provided complete data. All subjects were provided with a 0.454% stannous fluoride/sodium hexametaphosphate dentifrice to use over the next 3 months (12 weeks). Subjects were instructed to brush twice daily for 60 seconds using their assigned product. Toothbrushing was supervised for 3 days of each week. Clinical examinations using the Löe-Silness Gingival Index were performed at 6 and 12 weeks posttreatment. The 6-month scores after the use of the sodium fluoride/triclosan/copolymer dentifrice served as the baseline. After 12 weeks of product use, participants had statistically significantly less gingivitis by 54% and statistically significantly less bleeding by 55% on average compared to baseline. No adverse oral soft tissue effects were reported in the study. This study demonstrated that the use of an experimental 0.454% stannous fluoride/sodium hexametaphosphate dentifrice over a 12-week period provides a statistically significant and clinically relevant effect in the control of gingivitis among subjects who previously did not respond to 6 months of use of a sodium fluoride/triclosan/copolymer dentifrice.

Adult↗

PubMed2005

Sustained antibacterial actions of a new stabilized stannous fluoride dentifrice containing sodium hexametaphosphate.

Stannous fluoride has been used as a chemotherapeutic agent for years to improve oral health. The benefits of stannous fluoride in controlling caries, plaque, and gingivitis are directly associated with its antimicrobial actions. Recently, a novel dentifrice was developed that combines stannous fluoride with an anticalculus agent, sodium hexa. metaphosphate. A series of independent evaluations were conducted to assess the long-lasting antimicrobial activity of stannous fluoride in the new stannous fluoride/sodium hexametaphosphate dentifrice: an in vitro Live/Dead assay; an in vivo Plaque Glycolysis and Regrowth Model study; a rapid in vitro salivary bacteria metabolic activity study; and a 12-hour in vivo tin-retention study. In the Live/Dead study, the new stannous fluoride/sodium hexametaphosphate dentifrice killed approximately 90% to 99% of the salivary microbes 16 hours after a single exposure. Similarly, the stannous fluoride dentifrice produced statistically significant reductions in plaque acid production and plaque regrowth activity compared to plaque treated with a standard fluoride dentifrice at all time intervals measured after product exposure (15 and 45 minutes). Results from the final two studies collectively demonstrated the presence of total soluble tin, which serves as a marker for the active stannous fluoride, at levels above the minimum concentration for inhibition of salivary bacteria metabolic activity 12 hours posttreatment. These findings confirm the long-lasting antibacterial action of the new stannous fluoride dentifrice, which serves as a basis for its therapeutic benefits.

Analysis of Variance↗

PubMed2005

Anticalculus efficacy and safety of a stabilized stannous fluoride/sodium hexametaphosphate dentifrice.

The purpose of this study was to assess the anticalculus efficacy and long-term safety of a new stannous fluoride dentifrice containing sodium hexametaphosphate. This trial was a randomized, double-blind, parallel-group, 6-month study where, after a prophylaxis, subjects brushed twice daily with either a stabilized 0.454% stannous fluoride/13% sodium hexametaphosphate dentifrice (Crest Pro-Health) or a marketed multibenefit triclosan/copolymer control dentifrice. Study subjects were known to form supragingival calculus and had previously demonstrated the ability to form at least 1.5 mm using the Volpe-Manhold Calculus Index over a 2-month pretest period. Comparisons between treatments for anticalculus efficacy were performed using analysis of covariance. Eighty subjects were randomized into one of two treatment groups after stratification on gender and baseline calculus scores and then monitored for calculus formation, soft tissue tolerance, and extrinsic stain. The mean calculus score for the stannous fluoride/sodium hexametaphosphate group was statistically significantly lower than that of the triclosan/copolymer group at both months 3 and 6 (P < .01). At month 3, the stannous fluoride/sodium hexametaphosphate group had an adjusted mean 54% lower than that of the triclosan/copolymer group. At month 6, the stannous fluoride/sodium hexametaphosphate group had an adjusted mean 56% lower than that of the triclosan/copolymer group. Both dentifrices were well tolerated and neither dentifrice group developed appreciable extrinsic stain over the 6-month trial period. Overall, the stannous fluoride/sodium hexametaphosphate dentifrice had superior anticalculus efficacy relative to the marketed triclosan/copolymer control and a comparable soft tissue safety and extrinsic stain profile.

Adult↗

PubMed2005

Desensitizing effect of a stabilized stannous fluoride/Sodium hexametaphosphate dentifrice.

Stannous fluoride (0.4%) has been incorporated into oral hygiene products to reduce dentinal hypersensitivity since the 1960s. The present study was designed to assess the desensitizing efficacy of a stabilized 0.454% stannous fluoride/sodium hexametaphosphate dentifrice compared to a sodium fluoride control dentifrice. This was a double-blind, parallel-group, randomized clinical trial conducted according to the American Dental Association Guidelines for the Acceptance of Products for the Treatment of Dentinal Hypersensitivity. Seventy-seven subjects who met the entrance criteria were stratified based on age, gender, and air-sensitivity scores and randomly assigned to either the stabilized stannous fluoride/sodium hexametaphosphate dentifrice or the sodium fluoride control dentifrice. Subjects were instructed to brush twice daily for 8 weeks. Oral soft tissue examination and efficacy assessments including tactile (Yeaple probe) and thermal (Schiff Air Index) sensitivity were made at baseline, week 4, and week 8. The mean sensitivity score based on the Schiff Air Index for the experimental group was statistically significantly lower than that of the sodium fluoride control group, at both weeks 4 and 8 (P < .0001). The mean sensitivity score based on the Yeaple Probe Index for the stannous fluoride/sodium hexametaphosphate group was statistically significantly higher, indicating a reduction in sensitivity, than that of the sodium fluoride control group, at both weeks 4 and 8 (P < .0001). The results demonstrate that the stabilized stannous fluoride/sodium hexametaphosphate dentifrice provides clinically and statistically significant reductions in dentinal hypersensitivity when compared to the sodium fluoride control dentifrice.

Adolescent↗

PubMed2005

Extrinsic whitening effects of sodium hexametaphosphate--a review including a dentifrice with stabilized stannous fluoride.

The number of tooth whitening products available to patients has grown dramatically during recent years. While peroxide is the primary agent found in products that bleach and remove intrinsic sources of discoloration, various ingredients are incorporated in formulations to remove and inhibit extrinsic sources of tooth discoloration, ie, tooth stain. Recently, an advanced antitartar ingredient with extrinsic-stain-inhibiting benefits was introduced: sodium hexametaphosphate. This long-chain condensed phosphate, also known as polypyrophosphate, chemically removes existing stains and provides long-lasting inhibition of new-stain chromogen adsorption. Sodium hexametaphosphate was originally introduced in a sodium fluoride dentifrice formulation and was later marketed in a chewing gum delivery system. Recently, sodium hexametaphosphate was launched in another dentifrice formulation containing stabilized stannous fluoride (Crest Pro-Health). This article reviews published clinical and laboratory data demonstrating sodium hexametaphosphate's extrinsic whitening benefits in all three formulations.

Cariostatic Agents↗