Biomedical subjects

C Cao

Publications and source records attributed to C Cao.

At least 55 records · Page 3Linked to original sources

PubMed2000

[Induction of protective immune response in mice and rhesus monkeys by immunization with fusion protein of cholera toxin B subunit and multiples of Plasmodium falciparum].

Recombinant fusion protein of cholera toxin B subunit (CTB) and poly-valent protective epitopes of plasmodium falciparum was given to i.m. to C57BL/6j mice and rhesus monkeys three times. In rhesus monkeys, high level of antibodies for CTB (1:6400) and malaria epitopes (1:3200) amtobpdoes were elicited as well as the specific CTL activity for P. plasmodium. After the mice were challenged with sporozoites of P. yeolli, about 50% of them were protected from the patent infection. A blood-stage challenge with 10(8) of P. cynomolgi parasite were given to rhesus monkeys, which showed that two animals in control group were patent infection for at least 30 days, in contrast, the two animals immunized were recovered respectively at the day of 11 and 15 after challenges. The results suggested that cholera toxin acts as an effective adjuvent in the development of malaria vaccine.

Animals↗

PubMed2000

[Induction of protective immune responses in rhesus monkey by immunization with recombinant plasmids of polyvalent epitopes of Plasmodium falciparum using cholera toxin B as adjuvant].

The immunogenicity and protective efficacy of the DNA vaccine which include cholera toxin B subunit (CTB) and polyvalent protective epitopes of Plasmodium falciparum (awte gene) was assessed using rhesus monkeys as animal models. Recombinant plasmids of pCMV-CTB-AWTE were given to five rhesus monkeys three times with two weeks intervals by intramuscle (i.m.) route, immunization dose was 500 micrograms per plasmid per animal. High levels of anti-CTB and anti-malaria epitopes antibodies and P. falciparum epitope specific CTL activity were elicited. The vaccinated groups was challenged with 1.25 x 10(8) of P. cynomolgi parasites. All monkeys of the control group was patent for at least 34 days, the DNA vaccinated groups wasn't infected during the 60 days we detected. The cocktail DNA vaccine which contains multi-stage and multi-epitope antigen gene shows excellent immunogenicity and protective efficacy, the results also suggests that DNA vaccine plays an important role against malaria infection.

Animals↗

PubMed2000

Peri-implant mucosal inflammation and bone loss: clinical and radiographic evaluation of 108 dental implants after 1-year loading.

OBJECTIVE: To evaluate the clinical outcomes, and a possible correlation between peri-implant mucosal inflammation and marginal bone loss, 1 year after restoration in a group of Chinese patients with dental implants. METHODS: Observation of the clinical and radiographic parameters of 108 IMZ and Frialit-2 dental implants in 70 patients. RESULTS: One year after loading, there were no signs of mobility and peri-implant radiolucency in any of the implants. The average bone loss adjacent to implants was 0.63 mm (SD 0.78). The prevalence of peri-implant mucosal inflammation, as indicated by sulcus bleeding index (SBI) of 1.0 or more, was 32.9%. Significant positive correlation was found between mucosal inflammation and bone loss (P < 0.05). 92% of the observed sites had plaque index (PLI) scores greater than 1. CONCLUSIONS: The 1-year outcomes from this patient group indicate that IMZ and Frialit-2 implants provide satisfactory clinical results. One of the etiologic factors of alveolar bone loss around implants seems to be plaque-associated marginal inflammation. Improvement of oral hygiene, elimination of soft tissue inflammation, and proper treatment of periodontal disease of natural teeth are critical for maintaining the implants.

Adolescent↗

PubMed2000

[Rainfall interception capacity of forest canopy between two different stands].

Based on the observation data, the rainfall interception capacity of the canopy in plantation and natural forest stands and its relation to rainfall were examined using the method of taking maximum under the same rainfall. The results showed that the rainfall interception capacity of plantation forest increased rapidly with the increase of rainfall, because of its even distribution of branches and leaves, which was higher under low rainfall less than 30 mm, and the saturation interception capacity was easily reached, depending on the quantity of branches and leaves in the canopy. Although the interception capacity of natural forest was relatively weak under low rainfall less than 30 mm, compared with plantation forest, it was much stronger under heavy rainfall more than 30 mm. The saturation interception of natural forest was larger than that of plantation forest.

Ecosystem↗

PubMed2000

[Boron balance in agroecosystem on brown-red soil of south Hubei Province].

Five sequential cropping systems including rape/soybean-rice, wheat/watermelon-rice, rape/corn-soybean, wheat-sesame and soybean-sesame, were selected study the boron balance in agroecosystem on brown-red soil of south Hubei Province. The results show that the main output of boron was runoff and leaching, which accounted for 48-53% and 41% of the total respectively, while the output by products accounted for 3.4-10.1%. The main inputs were from rainfall, irrigation, fertilization seeds and seedlings, and natural return.

Boron↗

PubMed2000

[Ecological process of vegetation restoration in Caragana mirophylla sand-fixing area].

The occurrence and development of artificial vegetation after mobile sandy dunes being fixed by adopting straw check combining with seeding Caragana microphylla were studied. Especially the process of species invasion and the changes of community structure in 35 years were analyzed in detail. The results showed that the species richness of artificial community of C. microphylla increased, from 5 species (in 2 years) to 23 species in 35 years. In the structure concerning plant lifeform, therophytes were in dominant position, while the ratio of therophytes to all plant species had a tendency of decrease. The rates of species number and the quantity of hemicryptophytes and geocryptophytes increased gradually. Species diversity and community evenness indexes increased and ecological dominance index decreased gradually. The similarity index of the artificial plant community to natural one increased with age. The changes of physical and chemical property of soil were also discussed.

China↗

PubMed2000

[Titer and avidity of serum antibody to Porphyromonas gingivalis before and after periodontal therapy].

OBJECTIVE: To observe the changes of titer and avidity of serum antibody to Porphyromonas gingivalis (Pg) before and one month after periodontal therapy, and to observe the correlation of titer and avidity of anti-Pg IgG with clinical indices. METHODS: ELISA and DEA-ELISA were used to determine the titer and avidity of serum IgG antibody to Pg381 before and one month after periodontal treatment in 17 periodontitis patients and 6 healthy control subjects. RESULTS: The titers of anti-Pg IgG antibody were higher in periodontitis patients than in healthy control subjects (P < 0.001). All patients were seropositive (titers to Pg were higher than 2-fold above the median for control subjects). IgG antibody avidity to Pg in periodontitis patients were not found to be significantly lower than that in control group. The titers to Pg decreased significantly at one month after periodontal therapy, but antibody avidity didn't change. Serum anti-Pg antibody titers had a tendency of negative correlation with probing depth. The antibody titers were significant higher in periodontitis patients with < or = 5 mm mean probing depth than in patients with > 5 mm mean probing depth. CONCLUSIONS: It is suggested that the humoral immune response to Pg381 is protective and this protective effect mainly depends on the titer of antibody.

Antibodies, Bacterial↗

PubMed2000

[The role of IL-1 beta and TNF-alpha in hyper-reactivity of neutrophils in rapidly progressive periodontitis patients].

OBJECTIVE: Neutrophils (PMNs) from rapidly progressive periodontitis (RPP) was found to generate abnormally high levels of oxygen radicals. Elastase activity in gingival crevicular fluid (GCF) from RPP was also found much higher. It suggested that PMNs in some RPP patients are hyper-reactive. The purpose of this study was to investigate the mechanism of PMN hyper-reactivity by surveying the correlation of TNF-alpha level with elastase activity in GCF and by evaluating the association between PMN infiltration and the expression of IL-1 beta and TNF-alpha in gingival tissues from RPP patients. METHODS: 41 GCF samples from 22 RPP patients and 34 GCF samples from 11 healthy controls were collected. The total amount of TNF-alpha in GCF was detected using ELISA. The elastase activity was measured with a low molecular weight substrate (S2484) specific for granulocyte. The correlation of TNF-alpha level with elastase activity in a GCF sample was analyzed with Spearman correlation. 20 gingival specimens were obtained respectively from 10 RPP patients and 5 periodontally healthy controls. The expression of IL-1 beta and TNF-alpha was detected with immunohistochemistry. The distribution of PMN was observed with hematoxylin and eosin staining. RESULTS: Total amount of TNF-alpha in GCF was positively correlated with elastase activity (r = 0.44, P < 0.05). The IL-1 beta- and TNF-alpha-positive cells in gingiva were superimposed in areas where PMNs infiltration predominant. CONCLUSION: The hyper-reactivity of PMN in RPP patients was related to locally produced IL-1 beta and TNF-alpha.

Adult↗

PubMed2000

[The effect of non-surgical periodontal and adjunctive minocycline-HCL treatments on collagenase activity].

OBJECTIVE: To evaluate the effect of scaling and root planing combined with local application of 2% minocycline hydrochoride ointment(Periocline) on the level of collagenase activity releasing from PMNs in GCF. METHODS: This was a randomized, single-blinded, split mouth design study. The target sites of 31 patients with moderate to severe periodontitis (PD > 5 mm) was randomized by left-side and right-side into one of the two groups (the test group and the control group). Subsequently each patient was scheduled for two appointments for the full-month supra-gingival scaling and oral hygiene instruction. At baseline all patients received subgingival scaling and root planing and were followed by 4-time applications of Periocline with one-week interval for totally four weeks in the test group. All patients were taken GCF for measuring collagenase by the method of Nakashima et al (1996) and were examined based on four parameters, including plaque index, pocket depth, attachment loss and bleeding on probing. RESULTS: Four weeks after root planing with 4-time applications of Periocline, all clinical parameters and active collagenase in GCF decreased significantly in the test groups[(593 +/- 112) mU/sample vs (311 +/- 98) mU/sample, P < 0.001]. On the other hand, simple root-planing therapy had limited effect on the active collagenase[(611 +/- 123) mU/sample vs (523 +/- 127) mU/sample], although all clinical parameters were also reduce significantly. Interestingly, seven weeks later, gingival inflammation and the active collagenase were reduced more significantly than those after four-week root planing in both groups[Test: (311 +/- 98) mU/sample vs (207 +/- 57) mU/sample; CONTROL: (523 +/- 127) mU/sample vs (345 +/- 117) mU/sample, P < 0.001]. At eleven week, gingival inflammation and the level of collagenase activity were rebounded in the control group[(467 +/- 108) mU/sample]. However, in the test group they were kept in lower level[(213 +/- 121) mU/sample]. The level of collagenase activity showed significantly positive correlation with GCF volumes and AL in two groups. CONCLUSION: These results indicate that local application of 2% minocycline hydrochoride ointment may effectively inhibit the level of active collagenase from PMNs and may inhibit connective tissue breakdown by inhibiting neutrophil collagenase.

Adult↗

PubMed2000

[A one-year study on enzyme level in gingival crevicular fluid around osseointegrated dental implants].

OBJECTIVE: To investigate the changes of gingival crevicular fluid(GCF) volume, aspartate aminotransferase (AST) and alkaline phosphatase(ALP) levels in GCF around dental implants during the first year after rehabilitation. And to explore the relationships between these changes and peri-implant inflammation as well as bone loss. METHODS: 26 Branemark implants in 12 adults were included in this study. Examinations were carried out in a total of 52 sites in preinsertion period and 3, 6, 12 months following rehabilitation. RESULTS: GCF volume, GCF-AST, GCF-ALP were firstly increased and then fallen during the first year after rehabilitation. GCF volume, GCF-AST, GCF-ALP in sites with peri-implant mucositis were higher than those in health sites, and were increased with the severity of peri-implant mucositis. GCF volume, GCF-AST, GCF-ALP in sites with bone loss were significantly higher than those without bone loss. CONCLUSION: GCF volume, GCF-AST, GCF-ALP could reflect peri-implant inflammation and bone changes to some degree.

Adult↗

PubMed2000

[An analysis on need and demand for dental service in urban residents of Beijing].

OBJECTIVE: To analyze the needs and demands for dental services in urban residents of Beijing, and to forecast developmental trends of dental demand in the future. METHODS: There were 1,517 subjects examined by a stratified, clustering, random sampling, and a questionnaire survey were completed. RESULTS: The prevalence of oral diseases was 97.6%, but only 31.5% of subjects visited the dentist in a year, the total number of residents who had need of dental care were 4,412,010 more than that of demand level. Potential demand was mainly due to the negative awareness of people and problem from service provider. It was predicted that, if the potential demand caused by awareness and service provider were satisfied, the demand for dental care would increase by 69.4% and 13.2%, respectively. By the year of 2005, the demand will increase by 1.14%, and the value will be 3.76% in 2010. CONCLUSIONS: A substantial discrepancy is found between oral disease presence and demand for dental service. The levels of demand are also irrational. The large potential demand is caused by both receiver and provider's factors. At last, the future demand for dental care is forecasted under three hypothesis.

China↗

PubMed2000

[Changes of elastase in gingival crevicular fluid after periodontal treatment of adult periodontitis patients].

OBJECTIVE: To examine the changes of elastase in the supernatant (EA-s) and in the pellet (EA-p) after centrifuge in gingival crevicular fluid (GCF) before and after periodontal treatment. METHODS: GCF was sampled with filter paper strips by intra-pocket method to determine EA levels. Forty-three teeth of eight subjects were included. EA-s and EA-p were determined separately using the subtract Meosuc-ala-ala-val-pro-NA. RESULTS: EA-s per site and per ml, EA-p per site and the ratio of EA-s/EA-p (S/P) decreased significantly after non-surgical periodontal treatment (P < 0.001), while EA-p concentration didn't change (P > 0.05). CONCLUSIONS: GCF-EA-s and EA-p could act as objective parameters to evaluate the effect of periodontal therapy, especially EA-s and S/P, which may be sensitive diagnostic parameters for determining periodontal disease activity.

Adult↗

PubMed1999

An additional electrostatic interaction between adrenodoxin and P450c27 (CYP27A1) results in tighter binding than between adrenodoxin and p450scc (CYP11A1).

Mitochondrial cytochrome P450c27 (product of the CYP27A1 gene) is found to have significantly higher affinity for the common redox partner adrenodoxin than another mitochondrial P450, P450scc (product of the CYP11A1 gene). To investigate the basis of the approximately 30-fold difference in adrenodoxin binding, two sets of P450c27 mutants were generated, expressed in Escherichia coli, and purified. Mutations of one set were within the putative adrenodoxin-binding site containing conserved lysine residues also crucial in P450scc for binding adrenodoxin. The second set included mutations within a sequence aligning with the "meander region" of P450BM-3 proposed to be a site of redox-partner interactions in P450s (Hasemann, C. A., Kurumbail, R. G., Boddupalli, S. S., Peterson, J. A., and Deisenhofer, J. (1995) Structure 3, 41-62). Mutation of the P450c27 conserved lysines (K354A and K358A) led to a approximately 20-fold increase in apparent Ks for adrenodoxin, confirming that these two positively charged residues conserved in mitochondrial P450s are important for adrenodoxin binding. Mutation of Arg-418, conserved in the CYP27A1 family, to serine also decreased the affinity for adrenodoxin approximately 20-fold. This residue is predicted to be located in the meander region. A triple K354A/K358A/R418S mutation profoundly reduced adrenodoxin binding. Thus, in contrast to P450scc, where mutation of the two conserved positively charged residues results in virtually complete inhibition of adrenodoxin binding, in P450c27 there are three of such residues (Lys-354, Lys-358, and Arg-418) important for adrenodoxin interaction.

Adrenodoxin↗

PubMed1999

Lipopolysaccharide injected into the cerebral ventricle evokes fever through induction of cyclooxygenase-2 in brain endothelial cells.

Activation of the arachidonic acid cascade is an essential step for the development of fever during brain inflammation. We investigated the brain sites where this activation takes place by use of a rat model of brain inflammation. Intracerebroventricular administration of lipopolysaccharide but not of its vehicle evoked fever. The fever was markedly suppressed when the rats had been pretreated with a cyclooxygenase-2-specific inhibitor. In situ hybridization and immunohistochemical studies revealed that cyclooxygenase-2 mRNA and its protein were induced by lipopolysaccharide in blood vessels near the cerebral ventricles and in those in the subarachnoidal space. Double immunohistochemical staining revealed that these cyclooxygenase-2-positive cells were mostly endothelial cells. The time course of fever and that of cyclooxygenase-2 induction in the endothelial cells were in parallel. Cyclooxygenase-2 mRNA in a certain type of telencephalic neurons was also upregulated by the intracerebroventricular administration, but this neuronal response occurred both in vehicle-injected rats and in lipopolysaccharide-injected ones to the same extent. Therefore, the neuronal response was not essential to the development of fever. These results suggest that brain endothelial cells play a crucial role in the development of fever during brain inflammation by activating their arachidonic acid cascade.

Animals↗

PubMed1999

Titanium dioxide as photocatalyst on porous nickel: adsorption and the photocatalytic degradation of sulfosalicylic acid

The commonly used photocatalyst, TiO2 (anatase), has been immobilized on porous nickel using 3 wt.% polyvinyl alcohol (PVA) as the binder. The results show that sulfosalicylic acid (SSal) can be degraded on the developed catalytic system. The adsorption characteristics on TiO2-Ni system have been investigated. The observance of photocalytic degradation of SSal under pH values and initial concentrations can be explained by the adsorption behavior of SSal. The parameters of the Langmuir-Hinshelwood expression have been determined by different experimental ways and the results are satisfactory.

Journal Article↗

PubMed1999

Artifact detection in the PO2 and PCO2 time series monitoring data from preterm infants.

BACKGROUND: Artifacts in clinical intensive care monitoring lead to false alarms and complicate later data analysis. Artifacts must be identified and processed to obtain clear information. In this paper, we present a method for detecting artifacts in PCO2 and PO2 physiological monitoring data from preterm infants. PATIENTS AND DATA: Monitored PO2 and PCO2 data (1 value per minute) from 10 preterm infants requiring intensive care were used for these experiments. A domain expert was used to review and confirm the detected artifact. METHODS: Three different classes of artifact detectors (i.e., limit-based detectors, deviation-based detectors, and correlation-based detectors) were designed and used. Each identified artifacts from a different perspective. Integrating the individual detectors, we developed a parametric artifact detector, called ArtiDetect. By an exhaustive search in the space of ArtiDetect instances, we successfully discovered an optimal instance, denoted as ArtiDetector. RESULTS: The sensitivity and specificity of ArtiDetector for PO2 artifacts is 95.0% (SD = 4.5%) and 94.2% (SD = 4.5%), respectively. The sensitivity and specificity of ArtiDetector for PCO2 artifacts is 97.2% (SD = 3.6%) and 94.1% (SD = 4.2%), respectively. Moreover, 97.0% and 98.0% of the artifactual episodes in the PO2 and PCO2 channels respectively are confirmed by ArtiDetector. CONCLUSIONS: Based on the judgement of the expert, our detection method detects most PO2 and PCO2 artifacts and artifactual episodes in the 10 randomly selected preterm infants. The method makes little use of domain knowledge, and can be easily extended to detect artifacts in other monitoring channels.

Artifacts↗

PubMed1999

Artifact detection in cardiovascular time series monitoring data from preterm infants.

Artifacts in clinical intensive care monitoring lead to false alarms and complicate data analysis. They must be identified and processed to obtain true information. In this paper, we present a method for detecting artifacts in heart-rate (HR) and mean blood-pressure (BP) data from a physiological monitoring system used in preterm infants. The method uses three different types of artifact detectors: limit-based detectors, deviation-based detectors, and correlation-based detectors. Each identifies artifacts in the monitoring data from a different perspective. By integrating the individual detectors, we develop a parametric artifact detector, called CVDetector. The CVDetector is parametric because its performance depends on the specific values for the parameters in its component detectors. In a huge space of CVDetector instances, we have successfully discovered an optimal CVDetector instance, denoted by CVDetector. The sensitivity and specificity of CVDetector for HR artifacts is 94.8% (SD = 7.6%) and 90.6% (SD = 6.9%), respectively. The sensitivity and specificity of CVDetector for BP artifacts is 94.2% (SD = 5.3%) and 80.0% (SD = 12.4%), respectively.

Artifacts↗

PubMed1999

[The elastase activity in gingival crevicular fluid from rapidly progressive periodontitis].

OBJECTIVE: It is now generally accepted that polymorphonuclear neutrophil (PMN) chemotactic defect increases the patient's susceptibility to early-onset periodontitis. However, some reports including ours have failed to show defective PMN chemotaxis in rapidly progressive periodontitis(RPP) patients. The purpose of the study was to survey the role of PMN in the progression of RPP. METHODS: The elastase activity in gingival crevicular fluid from 22 RPP patients and 11 healthy controls were studied. For the control group and 12 RPP patients, 30 s GCF and clinical data were obtained at the first visit. For other 10 RPP patients, 30 s GCF and clinical data were collected prior to treatment and 4 weeks after scaling and root-planing. The elastase activity was measured with a low molecular weight substrate (L-Pyroglutamyl-L-prolyl-L-valine-p-nitroaniline, S2484) specific for granulocyte elastase. RESULTS: The pre-treatment elastase activity was much higher (0.63 +/- 0.38, Abs/site) in RPP patients than that in control subjects (0.07 +/- 0.05, Abs/site). The elastase activity was positively correlated with GCF volume, probing depth, attachment loss and gingival bleeding. Scaling and root-planing resulted in decrease of both clinical data and elastase activity. CONCLUSION: These results suggested that PMN with the increased accumulation or the increased release of lysosomal enzymes may play a role in the pathogenesis of RPP.

Adult↗