Plaque as a reservoir for active ingredients.
Explore the source record for details and available documents.
Calcium↗
Biomedical subjects
X J Gao
Publications and source records attributed to X J Gao.
Survival of glass ionomer restorations placed in primary molars using atraumatic restorative treatment (ART) and conventional cavity preparations: 2-year results.
OBJECTIVE: To compare the survival of glass ionomer cement (GIC) restorations placed in a dental clinic setting using both the atraumatic restorative treatment (ART) approach with hand instruments, and conventional cavity preparation with rotary instruments. METHOD AND MATERIALS: Two encapsulated high-strength conventional GICs (Fuji IX GP, Ketac-Molar Aplicap) were placed in 82 Class I and 53 Class II preparations and one encapsulated non-gamma 2 amalgam alloy (GK-amalgam) was placed in 32 Class I preparations, in the primary molars of 60 Chinese children with a mean age of 7.40 +/- 1.24 (SD) years. Thus, 9 treatment groups were formed. RESULTS: After two years, there were no significant survival differences found among 7 of the 9 treatment groups (p = 0.99). However, two groups comprising Fuji IX GP and Ketac-Molar Aplicap placed in Class II cavities prepared using the ART approach showed significantly lower restoration survivals (p < 0.001). Only 3 of the 72 initially sealed fissures adjacent to the restorations appeared to retain any GIC material. CONCLUSIONS: In a clinic setting, both the ART hand instrument and conventional rotary instrument methods were equally suitable for high Class I restoration survival, but not for Class II restoration survival where the conventional cavity preparation method was preferable.
Child↗
PEGylated polycyanoacrylate nanoparticles as tumor necrosis factor-alpha carriers.
The aim of this study was to find an effective carrier for recombinant human tumor necrosis factor-alpha (rHuTNF-alpha). The influence of solvent systems containing poly(methoxy-polyethyleneglycol cyanoacrylate-co-n-hexadecyl cyanoacrylate) (PEGylated PHDCA) on the biological activity of rHuTNF-alpha was investigated. The PEGylated PHDCA nanoparticles loading rHuTNF-alpha were prepared with the double emulsion method. The influence of main experimental factors on the entrapment efficiency was evaluated by the Uniform Design. The physicochemical characteristics and in vitro release of rHuTNF-alpha from the nanoparticles were determined. The results showed that serum albumin such as human serum albumin (HSA) or bovine serum albumin (BSA) could play a protective action on rHuTNF-alpha in the preparation process. At > or =2.0% (w/v) HSA concentration, more than 85% of rHuTNF-alpha activity remained and the role of HSA was not affected by copolymer concentrations from 0.5 to 3.0% (w/v). The entrapment efficiency of the nanoparticles was about 60% and the nanoparticle size was about 150 nm. The nanoparticles were spherical in shape and uniform with the value of the zeta potential about -9 mV. The rHuTNF-alpha release from the nanoparticle showed an initial burst and then continued in a sustained fashion. The results showed that the PEGylated PHDCA nanoparticles could be an effective carrier for rHuTNF-alpha.
Chemical Phenomena↗
Association of caries activity with the composition of dental plaque fluid.
This study tests the hypothesis that caries activity is associated with lower degrees of saturation with respect to enamel mineral in dental plaque fluid following sucrose exposure. Plaque fluids were obtained from caries-free, caries-positive, and caries-active subjects. Samples were collected before and at 3 and 7 min after a sucrose rinse on consecutive weeks and analyzed for organic acids, inorganic ions, pH, calcium activity, and, in selected samples, total protein. After sucrose, pH values were significantly lower in the caries-active group in comparison with the caries-free and caries-positive groups. Total and free calcium concentrations increased with decreasing pH, with free calcium being about one-third of total calcium. The caries-active group exhibited significantly lower degrees of saturation with respect to enamel mineral, after sucrose, and had significantly higher mutans streptococci levels in plaque than did the caries-free samples. Thus, saturation levels in post-sucrose plaque fluids reflect the cariogenic potential of dental plaque.
Adolescent↗
Stealth polycyanoacrylate nanoparticles as tumor necrosis factor-alpha carriers: pharmacokinetics and anti-tumor effects.
The objective of this study was to investigate the pharmacokinetics and in vivo anti-tumor effect of recombinant human tumor necrosis factor-alpha (rHuTNF-alpha) encapsulated in poly(methoxypolyethyleneglycol cyanoacrylate-co-n-hexadecyl cyanoacrylate) (PEG-PHDCA) nanoparticles. Our experimental results showed that PEG-PHDCA nanoparticles could extend the half-life of rHuTNF-alpha to 7.42 h and obviously change the protein biodistribution in tissues, and in particular, increase accumulation of rHuTNF-alpha in tumor. Compared with PHDCA nanoparticles and free rHuTNF-alpha, PEG-PHDCA nanoparticles loaded with rHuTNF-alpha showed higher antitumor potency at the same dose, which might be related to its higher accumulation in tumor tissues and longer plasma circulation time. Therefore, PEG-PHDCA nanoparticles could be an effective carrier for rHuTNF-alpha.
Animals↗
PEGylated recombinant human tumor necrosis factor alpha: pharmacokinetics and anti-tumor effects.
The aim of the present work was to investigate and assess the merit of PEGylated recombinant human tumor necrosis factor-alpha (rHuTNF-alpha) following our previous work. The rHuTNF-alpha was modified using activated polyethylene glycol (PEG), N-succinimidyl succinnate monomethoxy polyethylene glycol (SS-PEG). The pharmacokinetics and anti-tumor effect were investigated. The experimental results showed that PEGylated rHuTNF-alpha could obviously alter in vivo behavioral characteristics of rHuTNF-alpha. Among the synthesized PEG-rHuTNF-alphas with different PEG molecules, PEG20000-rHuTNF-alpha demonstrated the longest circulating half-life (24.8 h) which was about 50 times longer than that of rHuTNF-alpha (28.8 min). In addition, there was much more PEG20000-rHuTNF-alpha distributed into tumor tissues than other PEG-rHuTNF-alphas or rHuTNF-alpha with time, and PEG20000-rHuTNF-alpha also showed the highest anti-tumor potency. These results indicated that PEG20000-rHuTNF-alpha was a useful long circulating molecule with selective localization in tumor tissues and enhanced anti-tumor activity of rHuTNF-alpha.
Animals↗
Exposure to and actions against passive smoking in non-smoking pregnant women in Guangzhou, China.
BACKGROUND: The objective was to describe the extent of passive smoking exposure and preventive actions against passive smoking in non-smoking pregnant women and to analyze factors associated with preventive actions. METHODS: This was a cross-sectional survey on 1449 never-smoking pregnant women who made their first prenatal visit to the Women and Children's Hospital of Guangzhou, China during 1996-97. RESULTS: 60.2% (95% Confidence Interval 57.7%-62.7%) of the never-smoking pregnant women had a husband who currently smoked. Women with smoking husbands (n=872) were more exposed to ETS than those with non-smoking husbands (n=577) at home (71% vs. 33%), in public places (77% vs. 66%) and at work (60% vs. 50% of working women), and they took less actions against passive smoking in public places. Women with better education and knowledge on smoking and passive smoking had stronger preventive actions. CONCLUSIONS: Non-smoking pregnant women in China are often exposed to passive smoking and their preventive actions are weak. Passive smoking is an important obstetric and public health problem in developing countries and deserves urgent international attention.
Adult↗
A study of oral health condition in individuals with no oral hygiene and its association with plaque acidogenesis.
OBJECTIVE: To study the association of long-term deposited plaque, due to lack of oral hygiene, with acidogenesis of the plaque bacteria. METHODS: Seventy-seven subjects with poor oral hygiene were selected. Debris index (DI) and calculus index (CI) were recorded. Among them, 16 were DMFS > 8, and comprised the caries active (CA) group; 27 were caries free, and comprised the caries free (CF) group. Plaque fluids in both groups were analyzed for organic acids, phosphate, and inorganic cations by use of capillary electrophoresis, while pH was measured by microelectrodes. RESULTS: No differences were found on debris index (CF group measured 2.07-0.47, CA group measured 2.01-0.53) or calculus index (CF group measured 2.47-0.50, CA group measured 2.48-0.53) relative to carious status, although there was a positive relationship between DI and CI (r = 0.52, P < 0.001). The main finding in this study was that the quantity of lactic acid produced by sucrose exposure in these individuals with poor oral hygiene was much less (increased no more than 2 times, compared with content at rest) than in a previous report (increased 3 to 5 times, compared with content at rest) on subjects with good oral hygiene habits. CONCLUSIONS: Long-term deposited plaque due to lack of oral hygiene may have less cariogenic capability, although patients' susceptibility to periodontal disease would increase.
Acids, Acyclic↗
Bioelectrical impedance analysis (BIA) using bipolar foot electrodes in the assessment of body composition in Type 2 diabetes mellitus.
The use of bioelectrical impedance analysis (BIA) for determining human body composition is widely accepted as a safe, rapid, and reliable technique. Although this technique has been validated in normal and obese individuals, only limited studies have been done in special populations. The use of BIA for the measurement of body composition in Type 2 (non-insulin dependent) diabetic patients would be of particular interest for both clinical and investigative studies. The aim of this study was to evaluate the validity of a new bipedal BIA device for the measurement of body composition in a population of individuals with Type 2 diabetes mellitus. The body composition of 48 male and 48 female Type 2 subjects was measured by BIA and dual energy X-ray absorptiometry (DXA). The percentage body fat determined by BIA was significantly correlated with % body fat determined by DXA (r = 0.89, p < 0.0001). Agreement analysis showed that BIA consistently overestimated % fat in female diabetic subjects by approximately 5% and underestimated % fat in male diabetic subjects by approximately 10% of the predicted value obtained with DXA. These differences were statistically significant but probably of minor clinical relevance. We conclude that BIA measurement by TBF 105 is a useful and reliable technique for measuring body composition in subjects with Type 2 diabetes mellitus.
Adult↗
Comparison of methods for analyzing binary data arising from two-sample twin studies.
The study of twins is widely used for research into genetic and environmental influences on human outcome measurements. For the study design in which independent samples of monozygotic and dizygotic twins are compared with respect to their similarity on a binary trait, several statistical methods have been proposed. Using a Monte Carlo simulation, we compare the five following procedures: 1) goodness-of-fit method based on the common correlation model, 2) normal approximation of the maximum likelihood estimators of the common correlation coefficients, 3) Ramakrishnan et al. [(1992) Genet Epidemiol 9:273-282] method of odds ratio comparison, 4) generalized estimating equations method of odds ratio estimation, and 5) tetrachoric correlation method. The results show that the goodness-of-fit approach has similar or better performance in both type-one error rates and power than the other methods in all parameter settings. Its advantage with respect to type-one error rates is particularly clear under conditions of small sample sizes, extreme prevalences, or high values of the intraclass correlation coefficients. Therefore, the goodness-of-fit method is recommended for the two-sample twin study design.
Coronary Disease↗
Serum immunoreactive leptin concentrations in a Canadian aboriginal population with high rates of NIDDM.
OBJECTIVE: To better understand the relationship between leptin and the anthropometric and physiological variables associated with diabetes, we measured this protein in an isolated Canadian aboriginal population with very high rates of NIDDM. RESEARCH DESIGN AND METHODS: There were 728 individuals aged 10-79 years who participated in a population-based survey to determine the prevalence of NIDDM and its associated risk factors. Fasting blood samples for glucose, insulin, triglyceride, and leptin were collected; a 75-g oral glucose tolerance test was administered and a second blood sample drawn after 120 min. Height, weight, and waist and hip circumference were determined, and percent body fat was estimated using biological impedance analysis. Fitness level was assessed in a subsample of individuals using a validated submaximal step test. The relationship between serum leptin and the other variables was assessed using Spearman's correlation coefficients and multiple linear regression. RESULTS: Serum leptin concentration was strongly correlated with adiposity, and levels were substantially higher in female subjects in all age-groups. For male subjects, percent body fat, fasting insulin level, and waist circumference were significant independent predictors of log serum leptin concentration in a multiple linear regression model (R2 = 0.582). For female subjects, these variables plus glucose tolerance status were included in the final model (R2 = 0.633). Fitness level, when included with the main effects of the above models, was a significant predictor for male subjects only. CONCLUSIONS: In an isolated aboriginal community with high rates of diabetes, we found significant independent relationships between leptin and percent body fat and between leptin and fasting insulin. As documented in other populations, the higher leptin concentration among female subjects may reflect differential leptin production from different adipose tissue beds, or leptin resistance. Independent relationships also existed among leptin and glucose tolerance status in female subjects and fitness level in male subjects.
Adolescent↗
[Scanning microradiographic study on the kinetics of enamel demineralization].
Explore the source record for details and available documents.
Dental Enamel↗
Scanning microradiographic study of the kinetics of subsurface demineralization in tooth sections under constant-composition and small constant-volume conditions.
The kinetics of subsurface demineralization of tooth sections has been studied in real-time by scanning microradiography (SMR). Demineralization was carried out: (1) with a large volume of solution buffered to pH = 4 to maintain a constant composition; and (2) in a small constant volume (approximately 3 mL), buffered initially at pH = 4, so that the degree of saturation at the tooth surface increased as the tooth dissolved. At constant composition, the change in lesion depth, Y, with time, T, followed a linear relation, Y = a + bT, for T > 44 +/- 5 h. Before this time, the relation could be approximated by a linear one with different a and b constants. At constant volume, Y = q(1-e-r(T + s)) for all T, where q, r and s are constants. Similar relations, with different constants, were found for the mineral loss per unit area of lesion exposed to acid. These results showed that the process of demineralization under the rather severe conditions used was essentially a surface-controlled process. The change of slope at approximately 44 h and the presence of the constant s in the exponential function were attributed to a change in kinetics after formation of the surface layer.
Dental Enamel↗
A variant of HLA-DR4 determines susceptibility to rheumatoid arthritis in a subset of Israeli Jews.
HLA-DR4 is associated with risk for developing rheumatoid arthritis (RA) in most populations. In Israeli Jews, in whom the Dw10 subtype of DR4 predominates, no association of RA with DR4 has been found. The inability to detect an association could be due to the high frequency of DR4-Dw10. We used DNA typing with amplification by the polymerase chain reaction and dot-blotting with allele-specific oligonucleotides to determine DR4 variants in 131 Jewish RA patients living in Israel and 134 controls. In both Ashkenazi Jews and non-Ashkenazi Jews, the rare variant Dw15 (previously identified in Japanese populations and in Japanese patients with RA) was found to be the main allele associated with the risk of developing RA (relative risk = 9.2, corrected P less than 0.001). However, this low-frequency allele could be responsible for susceptibility in only 11.5% of the patients. Susceptibility for rheumatoid factor-positive RA was associated with Dw4 and Dw15; the risk for rheumatoid factor-negative RA was associated only with Dw14. The distribution of the HLA-DQ alleles associated with DR4 showed that more than half of the RA patients with Dw15 also had HLA-DQw2. The frequencies of DQw7 and DQw8 were not different in RA patients compared with controls. The results suggest that, as in other populations, susceptibility for the development of RA in Israeli Jews is associated with DRB1 locus alleles of the DR4 group.
Alleles↗
Alleles at four HLA class II loci determined by oligonucleotide hybridization and their associations in five ethnic groups.
The use of polymerase chain reaction (PCR) and oligonucleotide hybridization offers a new approach for the definition of HLA class II alleles. It has been possible to determine 43 alleles of DRB1, four of DRB3, two of DRB4, four of DRB5, eight of DQA1, and 14 of DQB1. These alleles are inherited together in members of families and form closely associated groups which are found repeatedly and in characteristic patterns in different populations. We have determined the HLA class II alleles and analyzed their association in 431 healthy unrelated subjects including 161 North American Caucasians, 53 Latin Americans, 61 Blacks, 88 Chinese, and 68 Israeli Jews. For-locus haplotypes (DRB1; DRB3/4/5; DQA1; DQB1) were derived from 79 B cell lines and the analysis of segregation in 34 nuclear families. The B-cell lines yielded 37 and the families showed the same, and 20 other, haplotypic combinations. In addition to these 57 haplotypes, associated alleles were assigned in the unrelated panels following certain rules. The resulting haplotypes were assigned to groups known to share associated alleles. The groups were: 1) DR1, DR2, and DRw10 (13 haplotypes); 2) DR3 and DRw6 (26 haplotypes); 3) DR5 and DRw8 (24 haplotypes); 4) DR4, DR7, and DR9 (24 haplotypes). Their distribution in populations with different ethnic backgrounds was analyzed. The expressed DRB4 allele and its null mutant were determined by PCR and oligonucleotide hybridization. The different DR7 haplotypes resulting from these determinations were analyzed in a panel of 130 North American Caucasoids. This comprehensive analysis of class II HLA haplotypes in human populations should be useful in understanding the role of these genes and in various applications including anthropology, disease susceptibility, and transplantation of allogeneic organs and tissues.
Alleles↗
Heterogeneity in HLA-DR2-related DR,DQ haplotypes in eight populations of Asia-Oceania.
The relative distributions of 480 DR2-related DR,DQ haplotypes have been determined in Australian Aborigines, Papua New Guinean Highlanders, coastal Melanesians, Micronesians, Polynesians, Javanese, and Southern and Northern Chinese. Using sequence-specific oligonucleotides (SSOs) for hybridization of polymerase chain reaction (PCR) products from DRB1, DRB5, DQA1, and DQB1 genes, 15 different DR2-related haplotypes were identified. The predominant DR2 haplotype in Oceania involved a novel combination of DRB1*1502, DRB5*0101 alleles; this haplotype occurred sporadically in Java, but not in China. In Southern China, the most frequent DR2 haplotype involved the unusual arrangement DRB1*1602,DRB5*0101; alternatively, DRB1*1602 was associated with a new DRB5 SSO pattern. This study has important implications for molecular HLA-typing protocols that assume particular DRB1, DRB5 or DR,DQ linkage relationships. Further, the novel DRB1, DRB5 haplotype in Oceania suggests that the mixed lymphocyte culture (MLC) determinants Dw2 and Dw12 are discriminated by codon 86 at the DRB1 locus.
Humans↗
DNA typing for class II HLA antigens with allele-specific or group-specific amplification. V. Typing for subsets of HLA-DR1 and DR'Br'.
Three DRB1 alleles of the DR1 group including DRB1*0101, DRB1*0102, and DRB1*0103 are currently recognized. The first two of these are defined as HLA-DR1 by serologic typing and as either Dw1 or Dw20 by typing with T cells. DRB1*0103, previously called DR'Br' or DR'BON', is not detectable by serology. Little information exists about the population frequencies of DRB1*0102 and DRB1*0103. In the present study we have used the polymerase chain reaction (PCR) and allele-specific oligonucleotide probes to determine these alleles. To avoid cross-hybridization with other DRB genes having the same DNA sequences as those of the region to be analyzed, we performed group-specific PCR to amplify only DR1 DRB1 genes. This was accomplished using a 21-nucleotide-long primer, homologous to the first hypervariable region common to the DR1 DRB1 genes, and which under appropriate conditions amplified only DRB1 genes of the DR1 group. Five oligonucleotide probes, one matching the second hypervariable region, two spanning the third hypervariable region, and two covering codons 82 through 89, were used to determine the three alleles. DRB1*0101 (Dw1) was found to be the major type of DR1 in North American Caucasians. In North American black and Brazilian mestizo populations DRB1*0102 (Dw20) was more prevalent. DRB1*0103 (DR'Br') was detected in only six individuals in the present study.
Alleles↗
DNA typing for HLA-DR, and -DP alleles in a Chinese population using the polymerase chain reaction (PCR) and oligonucleotide probes.
We have determined alleles of HLA-DRB1, DRB3, DRB5, DQA1, DQB1, and DPB1 loci in 91 unrelated healthy individuals from North China. Group-specific PCR primers were employed for the analysis of subsets of DR1, DR2, DR4, DRw52, and DPB. With allele-specific probes, 22 DRB1, 8 DQA1, 13 DQB1, and 12 DPB1 alleles were found in this panel. Allele frequencies showed that 25.3% of the subjects had DR7 and 26.4% had DR9, only 5.5% had DRB1*0301 (DRw17). In the DR4 group, DRB1*0405 (Dw15, 8.8%) and 0406 (KT2, 9.9%) were the most prevalent alleles. DRB1*0404 (Dw14.1), 0407 (Dw13.2) and 0408 (Dw14.2) were absent and the other alleles of the DR4 group were rare. The most common DRw6 subset was DRB1*1401 (8.8%). DRB1*0802 and 0803 were present (2.2%, 6.6%), and DRB1*0801 was not found. Associations with DQA1 and DQB1 were generally similar to those found in other populations. DPB1*0501 was the most frequent (60.2%) allele at the DPB1 locus. Overall our study shows that the distribution of class II alleles in a population from Mainland China is quite different from other ethnic groups. The high frequency of the KT2 subset of DR4. (DRB1*0406) and of DPB1*0501 are the most striking features found. A new type of DR4 was determined in one subject. It was like DR4-Dw15 (DRB1*0405) but, according to our hybridization patterns, it encoded valine instead of glycine in position 86. It is now called DRB1*0410.
Alleles↗