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Biomedical subjects

C Cao

Publications and source records attributed to C Cao.

At least 73 records · Page 4Linked to original sources
PubMed1999

[Helicobacter pylori in dental plaque of periodontitis and gastric disease patients].

OBJECTIVE: To investigate whether Helicobacter pylori(Hp) is a habitant in the oral cavity. METHODS: A polymerase chain reaction (PCR) assay with oligonucleotide primers homologous to a portion of the urease C and cytotoxin-associated gene A (cag A) of Hp was used to test for the presence of Hp in dental plaque. This assay was able to detect the expected 294 bp and 400 bp DNA fragments from as few as 100 Hp cells per reaction. Thirteen gastric disease patients (Group G) and 10 periodontitis patients (Group P) were recruited. A total of 276 supra- and subgingival plaque samples were collected, from 6 teeth in each subject for PCR assay. Clinical periodontal parameters including probing depth (PD), bleeding index (BI) and plaque index (PLI) of the sampled sites were recorded. RESULTS: In Group G, 11 of 13 patients had at least one Hp-positive plaque sample. 28.8% of the tested samples were urease C gene positive and 3.2% were positive for both urease C and cag A genes. All the 10 patients in Group P had at least one Hp-positive plaque sample. 49.2% of the tested samples were urease C gene positive and 3.3% were positive for both of the Hp genes. The prevalence of Hp was positively correlated with probing depth and bleeding index at the sampled sites. CONCLUSION: These results suggest that oral cavity is an ecological niche of Hp.

Adult↗
PubMed1999

[Gingival crevicular fluid enzyme levels at different destruction sites in the same teeth].

OBJECTIVE: To direct selecting proper sampling methods and sites in clinical research. METHODS: Gingival crevicular fluid (GCF) was sampled separately at the mesial-buccal and distal-buccal sites in the same teeth, which were destroyed differently. Clinical parameters were recorded in the subject sites and its adjacent sites. Aspartate Aminotransferase (AST) and Alkaline Phosphatase (ALP) in the GCF were determined. Difference of the enzyme levels between the two sampling sites, and relations between the enzyme level and all the clinical parameters were assessed. RESULTS: GCF-AST, ALP per sample at severely diseased sites were much higher than that from healthy and/or mild sites in the same teeth. Significant positive correlation (P < 0.001, r > 0.5) was demonstrated between enzyme levels in the sampling sites and probing depth (PD) and attachment level (AL) of the lingual sites. However, there was mild significant correlation (P < 0.05, r = 0.275) between ALP level in the sampling sites and PD of the proximal-buccal sites of its adjacent teeth. No significant correlation (P > 0.05) was found between AST level in the sampling sites and PD, AL of the adjacent teeth sites, and also between ALP level in the sampling sites and AL of the adjacent teeth sites. CONCLUSION: Site-specificity of periodontal disease was further demonstrated. GCF components were influenced reciprocally more obviously in the same proximal than by other sites.

Adult↗
PubMed1999

[Relevance of Fc gamma R polymorphism to the susceptibility of early-onset periodontitis].

OBJECTIVE: To investigate the polymorphism of the Fc gamma R genotype and its association with the susceptibility of early-onset periodontitis (EOP). METHODS: DNA of the white blood cells from 33 subjects with EOP and 27 healthy controls was extracted. Genotypes of the Fc gamma RIIA and Fc gamma RIIIB were determined by PCR followed by BstUI restriction endonuclease digestion and DNA sequencing, respectively. Then compared the differences in distribution of each genotype. RESULTS: No statistical difference in distribution of Fc gamma RIIA was observed between patients and controls. However, a significant over-representation of the Fc gamma RIIIB NA1/NA1 was found in EOP. CONCLUSION: These results suggest that the Fc gamma RIIIB NA1/NA1 may be a risk indicator for the susceptibility of the EOP.

Adolescent↗
PubMed1999

[Clinical evaluation of gingival sulcus temperature in healthy subjects].

OBJECTIVE: To evaluate gingival sulcus temperature in healthy subjects. METHODS: Small size, high sensitivity and rapid response thermocouple was used to measure the gingival sulcus temperature in seven dental students with healthy periodontium. 28 teeth in each subject were tested. RESULTS: For an individual subject, the gingival sulcus temperatures in all sites were always lower than sublingual temperature. There was obviously increased temperature gradient from anterior teeth to posterior teeth. The mean gingival sulcus temperatures on buccal sites were lower than that on lingual sites. There was no significant difference between maxillary and mandibular corresponding sites on lingual side. However, mandibular temperature was significantly lower than maxillary temperature on buccal side. Mandibular buccal temperature was the lowest in all tooth surfaces. CONCLUSION: Gingival sulcus temperature in subjects with healthy periodontium is easily influenced by environmental factors.

Adult↗
PubMed1999

[Genetic analysis of tooth development and eruption in 82 pairs of female-female twins].

OBJECTIVE: To study the heritability of tooth development and eruption. METHODS: 82 pairs of female-female twins between 6-12 years old were collected. Twin zygosity diagnosis were made by DNA-fingerprinting. The number of third molar present, hypodontia, upper lateral incisor malformation and the number of erupted permanent teeth were recorded by oral examination and panoramic radiographs, their heritabilities were calculated. RESULTS: According to the level of heritability, the dental traits were aligned as follows: the number of third molars present, the upper lateral incisor malformation, hypodontia and the number of erupted permanent teeth. CONCLUSION: Though both the tooth development and its eruption were under genetic influence, the heritability of tooth development was far more than tooth eruption.

Adolescent↗
PubMed1999

[Intermittent-pulse treatment of onychomycosis with orally administered itraconazole].

Fifty-four patients received an intermittent regimen of itraconazole (26 of them were finger onychomycosis and 28 toe onychomycosis) and were followed-up for nine months. The result showed that the clinical cure rate of fingernails was 88.5% and the mycologic cure rate was 96.4%, while the clinical cure rate of toes was 82.1% and the mycologic cure rate was 96.4%. Few adverse events were observed by 7.4%, just like nausea, gastric discomfort etc. It suggests that the pulse administration system is highly effective and has a few side-effects.

Adolescent↗
PubMed1999

[Effect of tian ma cu zhi chongji medicinal granules (TMCZCJ) on blood rheology in hypostasis rats due to stagnation of liver-qi and learning-memory disorder in cerebral ischemia-reperfusion mice].

OBJECTIVE: To investigate the effect of TMCZCJ on the blood rheology in hypostasis rats due to stagnation of the liver-qi and on the learning-memory disorder in cerebral ischemia-reperfusion mice. METHOD: The models of hypostasis due to stagnation of the liver-qi were made by combining irritation with hypodemic injected adrenalin and ice-bath in rats, and the models of learning-memory disorder were made by repeatedly ligating-reperfusing the bilateral carotid in mice. The hypostasis rats and learning-memory disorder mice were perorally administrated TMCZCJ(7.7, 15.4 g.kg-1) once a day, for fourteen consecutive days. RESULT: TMCZCJ can significantly reduce plasma viscosity, blood viscosity and reduced viscosity in hypostasis rats. It can also improve the latent learning-memory capability and memory gain-repetition ability in water-maze for cerebral ischemia-reperfusion mice. CONCLUSION: TMCZCJ can improve remarkably blood rheology in hypostasis rats and learning-memory disorder in cerebral ischemia-reperfusion mice.

Animals↗
PubMed1998

Effects of age, available response time and gender on ability to stop suddenly when walking.

Background: Injuries may occur during walking when a sudden stop to avoid a gait path obstacle is called for unexpectedly, but cannot be completed in the time available. Little is known about abilities, particularly those of older adults, to stop suddenly. Methods: Twenty young (mean age 23.4 years) and 20 older (72.6 years) healthy and physically active adults with equal numbers of females and males in each age group were studied. While walking straight ahead at approximately 1.3 m/s, they were cued by a light at one of five possible locations to stop as quickly as possible. Subjects were given available response times (ART), the times between the visual cue to stop and potential passage through a virtual wall that was outlined by the array of lights used to cue the subjects, ranging from 375 to 825 ms in 75-ms increments. The rate of success (RS) in completing the stops as prescribed was determined and the effects on RS of age, available response time and gender were examined. Regression analyses were used to interpolate the RS data. Results: At all ART, older female (OF) subjects had a significantly lower rate of success (RS) than either older male (OM) or young adult (YA) subjects. At an ART of 525 ms, for example, RS was 58% for YA and 51% for OM, but only 23% for OF. The regression analyses suggested that OM in the mean would have needed 10 ms longer and OF 70 ms longer than YA to achieve a 50% RS. No significant gender difference in RS were found among YA. Conclusions: The healthy and physically active older female subjects in this study needed longer available response times, and thus longer available stopping distances, than did the young adults or the older males to succeed as well in stopping suddenly while walking at their comfortable gait speed. Copyright 1998 Elsevier Science B.V.

Journal Article↗
PubMed1998

Brain endothelial cells express cyclooxygenase-2 during lipopolysaccharide-induced fever: light and electron microscopic immunocytochemical studies.

Cyclooxygenase-2 (COX-2), a key enzyme in the biosynthesis of prostaglandins, is induced in brain blood vessels by pyrogens, and its essential role in fever has been hypothesized. In this study, we determined (1) the type of cells that express cyclooxygenase-2 in brain blood vessels of lipopolysaccharide-treated rats, and (2) the precise relationship between the time course of fever and that of cyclooxygenase-2 protein expression in these cells. Five hours after the lipopolysaccharide injection (100 microg/kg, i.p.), cyclooxygenase-2-like immunoreactive cells were found in the parenchymal and subarachnoidal blood vessels. In these blood vessels, the cyclooxygenase-2-like immunoreactivity was restricted to the perinuclear region of the endothelial cells as revealed by a laser confocal microscopy, double-immunofluorescence staining with an endothelial marker, and immunoelectron microscopy. On the other hand, the cyclooxygenase-2-like immunoreactive cells were distinct from microglia or perivascular/meningeal macrophages as revealed by double immunostaining with macrophage/microglia-specific antibodies. Cyclooxygenase-2-like immunoreactive cells were first found at 1.5 hr after the lipopolysaccharide injection, at which time the fever had not been developed. After that, the number of cyclooxygenase-2-like immunoreactive cells and fever followed a similar time course, both being highest at 5 hr after the lipopolysaccharide injection and both returning to the baseline by 24 hr. These results demonstrate that brain endothelial cells are the primary sites where the activation of arachidonic acid cascade takes place during fever after intraperitoneal injection of lipopolysaccharide.

Animals↗
PubMed1998

Inhibition of FtsZ polymerization by SulA, an inhibitor of septation in Escherichia coli.

The bacterial cell division protein FtsZ assembles into the cytokinetic Z ring that directs cytokinesis in prokaryotes. In Escherichia coli the formation of the Z ring is prevented by induction of the cell division inhibitor SulA (SfiA), a component of the SOS response. Here we show that a MalE-SulA fusion that retains this inhibitory function in vivo inhibits the GTPase activity and polymerization of FtsZ in vitro. MalE-SulA10, which does not block Z ring formation in vivo, is unable to inhibit the GTPase activity and polymerization in vitro. Furthermore, FtsZ114, which is refractory to SulA in vivo, is not inhibited by MalE-SulA. These results indicate that SulA blocks Z ring formation by blocking FtsZ polymerization.

ATP-Binding Cassette Transporters↗
PubMed1998

Sudden turns and stops while walking: kinematic sources of age and gender differences.

Background: Significant age and gender differences were found among healthy young and older adult subjects in their abilities to quickly turn or stop in order to avoid obstacles that suddenly appear in the gait path (Cao C, Ashton-Miller JA, Schultz AB, Alexander NB. Abilities to turn suddenly: effects of age, gender and available response time. J Gerontol Med Sci 1997;52A:M88-M93; Cao C, Ashton-Miller JA, Schultz AB, Alexander NB. Abilities to stop suddenly: effects of age, gender, gait phase, and available response time. Submitted for publication, 1997 (also available as a chapter in Cao C. Biomechanics of forward momentum arrest when walking: age and gender differences. PhD Dissertation, University of Michigan, 1996). The present study quantified the extent to which age and gender differences in those subjects' response kinematics affected the total time they needed to suddenly arrest their forward momentum. Methods: Age- and gender-group means of four measures of forward movement of the anterior surface of the abdomen were obtained: the duration of the first post-cue response phase, from the visual cue that initiated the arrest response to reaching peak velocity (T1); acceleration (A1) during this phase; and decelerations (D2 and D3) during two subsequent post-cue response phases. A three-line-segment representation of this forward velocity history was constructed. This representation was used to predict the differences in response time needed (NRT) to suddenly arrest momentum that resulted from measured age and gender differences in each of the four response kinematics measures. Results: The largest contributor to the age group difference found in NRT was the increase in T1 among the older adults. Among the older males, the next largest contributor was their larger value of A1, and among the older females, their substantially smaller value of D2. Among the young adults in sudden turns, no single kinematic parameter seemed primarily responsible for the gender difference found in the NRT. Among the older adults, the gender difference in D2 was almost fully responsible for the gender difference in NRT, in both sudden stops and turns. Conclusions: Much of the older adults' need for longer response times than those of the young was attributable to the lengthened first phase of their responses. Older females, in addition, needed longer response times than young adults or older males because, during the second phase of their responses, their decelerations were substantially smaller. These age and gender differences may have arisen in part from known age and gender differences in abilities to develop lower extremity joint torque strengths rapidly. Copyright 1998 Elsevier Science B.V.

Journal Article↗
PubMed1998

Cyclooxygenase-2 is induced in brain blood vessels during fever evoked by peripheral or central administration of tumor necrosis factor.

Cyclooxygenase-2 (COX-2) is an inducible type of enzyme that is involved in prostaglandin biosynthesis. In the present study, we examined whether or not COX-2 is involved in fever that is induced by tumor necrosis factor-alpha (TNF-alpha) and, if so, where in the brain COX-2 is induced by this factor. Intraperitoneal (i.p.) injection of TNF-alpha into rats evoked a fever that started 1 h after the TNF injection, peaked 3 h after the injection, and then gradually declined. The fever was suppressed by pretreatment with a COX-2-specific inhibitor. With a time course similar to that of fever, COX-2 mRNA was induced in brain blood vessels. On the other hand, in some of the telencephalic neurons, COX-2 mRNA was constitutively expressed under the normal condition; but its level gradually decreased during the course of fever. Fever was also evoked by an intracerebroventricular (i.c.v.) injection of TNF-alpha. This febrile response was also suppressed by a COX-2 specific inhibitor and was associated with the induction of COX-2 mRNA in the brain blood vessels. On the other hand, the telencephalic neurons did not show consistent change in COX-2 mRNA level after i.c.v. injection of TNF-alpha or saline. COX-2-like immunoreactivity was found in some cells of the brain blood vessels 3 h after the TNF-alpha injection by either i.p. or i.c.v. route. Most of the COX-2-like immunoreactive cells were endothelial cells since COX-2-like immunoreactivity was colocalized with von Willebrand factor, an endothelial cell marker, in the same cells. These results suggest that the brain blood vessels are the major sites where TNF-alpha enhances PG biosynthesis after peripheral as well as after central injection, and provides further evidence supporting the hypothesis that COX-2 induced in the brain blood vessels is involved in fever.

Animals↗
PubMed1998

Electron-beam CT angiography with three-dimensional reconstruction in the evaluation of coronary artery bypass grafts.

RATIONALE AND OBJECTIVES: The authors evaluated the use of electron-beam computed tomographic (CT) angiography and three-dimensional (3D) reconstruction for evaluation of coronary artery bypass grafts (CABGs). MATERIALS AND METHODS: Sixty patients (53 men and seven women; mean age, 56 years +/- 8) with 152 CABGs (29 internal mammary artery and 123 saphenous vein grafts) underwent electron-beam CT with 3D reconstruction. The time from bypass surgery to CT scanning was 7 days to 120 months (mean, 17 months +/- 28). Enhanced single-section and flow mode studies were performed in all cases. The results were correlated with CABG operation records, and patency was determined with time-attenuation curves. RESULTS: All patients were successfully examined. On the basis of time-attenuation curve criteria, 124 (81.6%) of 152 grafts were patent. The patency rate for the internal mammary artery subgroup was 93% (27 of 29 grafts); for the saphenous vein graft subgroup, 78.9% (97 of 123 grafts). CONCLUSION: Used in contrast-enhanced, single-section mode and flow studies with time-attenuation curves, electron-beam CT angiography with 3D reconstruction can provide quantitative data for evaluation of CABG patency.

Adult↗
PubMed1998

Dynamic decision analysis in medicine: a data-driven approach.

Dynamic decision analysis concerns decision problems in which both time and uncertainty are explicitly considered. Two major challenges in dynamic decision analysis are on proper formulation of a model for the problem and effective elicitation of the numerous time-dependent conditional probabilities for the model. Based on a new, general dynamic decision modeling framework called DynaMoL (Dynamic decision Modeling Language), we propose a data-driven approach to addressing these issues. Our approach uses available problem data from large medical databases, guides the decision modeling at a proper level of abstraction and establishes a Bayesian learning method for automatic extraction of the probabilistic parameters. We demonstrate the theoretical implications and practical promises of this new approach to dynamic decision analysis in medicine through a comprehensive case study in the optimal follow-up of patients after curative colorectal cancer surgery.

Bayes Theorem↗
PubMed1998

[Reconstruction of the floor of mouth with facial artery musculocutaneous flap].

In order to study the clinical efficacy of facial artery musculocutaneous flap on repairing the defect of the floor of mouth, 21 patients had received this type of treatment from 1991 to 1997. The size of the flaps ranged from 8.0 x 3.4 cm to 12.1 x 5.4 cm and the average age of these patients was 59.5 years old. The donor site was closed directly. Nineteen flaps survived completely, while necrosis occurred at the apex of the other 2 flaps, which healed by ordinary management. The applied anatomy of the flap and the design and the main points of the operation were reported in details. The advantage of the flap and the prevention of facial malformation following operation were discussed. The conclusion was that this type of flap was ideal for reconstruction of the defects of floor of the mouth.

Adult↗
PubMed1998

Induction of diagnostic test strategies with multi-level information measures.

This paper presents a method for inducing clinical diagnostic test protocols or strategies from data. We represent testing strategies as a strategy tree. To support induction of strategy tree, we define three information measures: K-level information, K-level information gain, K-level gain ratio, and K-level cost index, for test selection during strategy building. These measures generalize Quinlan's information measures used in decision tree induction. We present theoretical and experimental results to show that the K-level cost index can be used to induce strategy trees in a practical domain.

Algorithms↗