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Biomedical subjects

C Cao

Publications and source records attributed to C Cao.

At least 91 records · Page 5Linked to original sources

Modelling medical decisions in DynaMoL: a new general framework of dynamic decision analysis.

Dynamic decision analysis concerns decision problems in which both time and uncertainty are explicitly considered. We present a new dynamic decision analysis framework, called DynamoL, that supports graphical presentation of the decision factors in multiple perspectives. To alleviate the difficulty in assessing conditional probabilities over time in dynamic decision models, DynaMoL incorporates a Bayesian learning system to automatically learn the probabilistic parameters from large medical databases. We describe the DynaMoL modeling and learning architecture through a medical decision problem on the optimal follow-up schedule for patients after curative colorectal cancer surgery. We also show that the modeling experience and results indicate practical promise for the framework.

Artificial Intelligence↗

[One stage repair of intraoral defects after radical operation of oral carcinoma by facial vessels pedicled naso-labial myocutaneous flap].

In order to repair the intraoral defects after extensive resection of oral carcinoma with radical neck lymph nodes dissection, the nasolabial myocutaneous flap was prepared with its pedicle which only contained the facial artery and anterior facial vein. After removal of the tumor, the flap was used to cover the intraoral defect. Altogether 15 cases of oral squamous cell carcinoma were treated by this method. Seven out of 15 cases had their cervical lymph nodes involved. The tumor in all cases were located in one anatomical region, without involvement of accessory nerve or metastasis. All the flaps survived after the operation. There was no recurrence of tumor in any case after being followed up from 0.5-2 years. Removal of tumor and repaire of the defect by pedided naso-labial myocutaneous flap could be done in one stage. The detail of the process was introduced. Its feasibility and application were discussed. It was suggested that preserving the facial vessels be a kind of modified method of radical neck lymph nodes dissection, and the nasolabial myocutaneous flap have some clinical value in repair of the defect after radical operation of oral carcinoma.

Adult↗

Three-dimensional reconstruction of electron beam computed tomography angiography for evaluating coronary artery bypass grafts.

OBJECTIVES: To probe into electron beam computed tomography (EBCT) angiography and 3-D reconstruction of coronary artery bypass grafts (CABG) and to evaluate the clinical application of EBCT angiography and 3-D reconstruction of CABG. METHODS: EBCT angiography with 3-D reconstruction was achieved in 150 patients (142 men and 8 women, mean age, 57 +/- 8 years) with 399 grafts including 100 internal mammary artery grafts (IMG), 296 saphenous vein grafts(SVG) and 3 radial artery grafts (RAG) respectively. The time from bypass surgery to EBCT scanning ranged from 7 days to 120 months, averaging 15 +/- 28 months. Enhanced single slice mode (SSM) and flow studies were performed in all patients. The results of 3-D reconstruction of CABG were compared with bypass operation records and with coronary arteriograms (7 patients). RESULTS: 150 patients underwent successfully EBCT angiography and CABG 3-D reconstruction. According to 3-D reconstruction of the coronary bypass grafts with flow studies, 318 of 399 coronary bypass grafts were patent including IMG patency in 87/100 (87%), SVG in 228/296 (77%) and RAG in 3/3 (100/100). The overall patent rate was 79.7%. In 7 patients with 12 coronary bypass grafts, EBCT studies showed graft patency (7 grafts) and occlusion (5), which were confirmed by conventional graft angiography. CONCLUSIONS: EBCT angiography with 3-D reconstruction is effective in providing the entire anatomic structure of coronary bypass grafts and evaluating coronary bypass graft patency. EBCT flow study can provide quantitative data for evaluating coronary bypass graft patency and for supplemental diagnosis of CABG 3-D reconstruction. EBCT angiography is a noninvasive technique that could replace conventional coronary arteriography for follow-up survey of coronary bypass surgery in future.

Adult↗

[Significance of bcl-2 gene breaking and bcl-2 protein expression in nasopharyngeal carcinoma].

In order to study the relationship between bcl-2 gene and nasopharyngeal carcinoma. The two hot breakpoints of bcl-2 gene and bcl-2 protein expression were examined by in situ hybridization and immunohistochemistry technique in 41 nasopharyngeal carcinoma(NPC) tissues. bcl-2 gene breakpoint were found in 4 cases of NPC(positive rate 9.8%). 34 cases of NPC expressed bcl-2 protein, the positive incidence was 82.9%. No statistically significant differences was found in histological grades. All benign lesions were negative for bcl-2 gene breaking and bcl-2 protein expression. There was no corresponding relation between bcl-2 protein expression and bcl-2 gene breaking. The results implicated that bcl-2 gene breaking may not play an important role in the pathogenesis of NPC. It also suggested that overexpression of bcl-2 protein may involved in carcinogenesis of nasopharyngeal epithelium.

Carcinoma, Squamous Cell↗

[Existence of IL-8 degrading protease and anti-IL-8 IgG in gingival crevicular fluid].

OBJECTIVE: To identify the nature of the IL-8 inhibitor(s) in gingival crevicul fluid (GCF). METHODS: (1) 14 GCF samples were collected from 13 adult periodontitis (AP) patients, and 9 samples were taken from 8 healthy subjects. Each GCF sample was divided into two aliquots. A serine protease-specific inhibitor-PMSF was added to one aliquot and PBS added to the other aliquot as control. ELISA was used to measure IL-8 level in the samples. (2) 41 GCF samples were collected from 15 AP patients and indirect ELISA was performed to detect the anti-IL-8 IgG antibody. RESULTS: (1) IL-8 level in the PMSF-added samples were significantly greater than that in the control group(3.01 mg/L +/- 5.79 mg/L vs 0.05 mg/L +/- 0.15 mg/L, P < 0.001). (2) The mean value of anti-IL-8 IgG in GCF was greater than that of negative control +3 x s. CONCLUSION: A serine protease which can "cleave" IL-8 exists in GCF and GCF from AP sites contain auto-antibody against IL-8.

Autoantibodies↗

[Chemotactic response of polymorphonuclear neutrophil to FMLP and IL-8 in rapidly progressive periodontitis patients].

OBJECTIVE: It has been reported that 48%-85% of rapidly progressive periodontitis (RPP) are associated with a defect in polymorphonuclear neutrophil (PMN) chemotactic function. However, some reports failed to detect any defect in PMN chemotaxis in RPP patients. Further, the influence of race on neutrophil function has been suggested. The purpose of the present study was to determine the PMN chemotactic function in Chinese RPP patients. METHODS: Neutrophils were obtained from heparinized peripheral blood of 16 RPP and 14 periodontally healthy control subjects matched for age and sex. Cells were isolated by Percoll discontinuous density gradient centrifugation. Chemotaxis was evaluated using modified Boyden chamber. (N-formyl-methionyl-leucyl-phenylalanine, FMLP) (10(-8) mol/L) and IL-8 (100 micrograms/L) which is a more specific neutrophil chemokines were used in this study. The results were determined by staining the filters followed by visual counting under microscopy at 600 x. Data was analyzed using the Students' t test and the value of RPP was compared with that of control subjects(> mean +/- 2s or < mean +/- 2s). RESULTS AND CONCLUSION: The results showed all RPP patients had normal PMN chemotactic behavior.

Adult↗

[Relationship between elastase activity and leukocyte counts in gingival crevicular fluid].

OBJECTIVE: To determine the relationship among the elastase(EA) activity in the supernatant (EA-s), and in the pellet (EA-p) after centrifuge, and polymorphonuclear leukocyte (PMN) counts in gingival crevicular fluid. METHODS: Gingival crevicular fluid (GCF) was sampled with filter paper strips by intra-pocket method to determine EA levels and then with gingival crevicular washings after 24 hours at the same site for PMN counting. The levels of EA-s and EA-p were determined seperately using the subtract Meosuc-ala-ala-val-pro-NA. PMNs at the same site were counted with light microscope. RESULTS: The research demonstrated significantly positive correlation among EA-s and EA-p per site and the PMN counts in GCF (P < 0.001). CONCLUSION: GCF-EA-p per site could reflect the amount of PMNs collected from the pockets, and EA can be the marker of PMN in GCF.

Adult↗

[Comparison of sampling methods and their effects on alkaline phosphatase levels in gingival crevicular fluid].

OBJECTIVE: To observe the change of alkaline phosphatase (ALP) after repeat sampling and compare the two sampling methods (orifice method and intra-pocket method). METHODS: Gingival crevicular fluid (GCF) was sampled repeatedly by the interval of 20 minutes, with orifice and intra-pocket method respectively, and the levels of ALP in GCF were determined. RESULTS: Mean levels of ALP per site and concentration of ALP are not statistically different between two samples after repeat sampling with-orifice method as well as intra-pocket method (P > 0.05). ALP levels (per site and per microliter) are much higher for intra-pocket method than orifice method (P < 0.001). From the viewpoint of the numbers of recovery sites after repeat sampling, though ALP levels at most sites can't entirely recover to their original levels with both method, intra-pocket method is still a little better than orifice method, and ALP levels per site is better than ALP concentration. CONCLUSION: The interval of repeat sampling should be prolonged more than 20 minutes. It is better to determine the GCF-ALP with intra-pocket method and also the recommended pattern that express enzyme levels is total activity per site but not concentration.

Adult↗

Possible role of cyclooxygenase-2 in the brain vasculature in febrile response.

These results support the hypothesis that the brain vasculature is the site of PGE2 production responsible for LPS-induced fever. LPS seems to increase the PGE2 level in the entire brain via the induction of COX-2. Fever may be mediated by PGE2 which is produced in the blood vessels in the preoptic area or which is produced in other parts of the brain and transported to the preoptic area through the ventricular system.

Animals↗

Induction of cyclooxygenase-2 in the brain by cytokines.

The present study revealed that (1) a pyrogenic dose of IL-1 beta induced COX-2 mRNA in the brain vasculature and leptomeninges, and (2) the cells positive for COX-2 mRNA in the blood vessels were endothelial cells that possess receptors for IL-1. These results imply that circulating IL-1 beta acts on its receptor on the endothelial cells of the brain vasculature to induce COX-2 mRNA, which is possibly responsible for the elevated level of PGE2 seen during fever. In this sense, the endothelial cells in the brain vasculatures seem to play a role as an interface between the blood borne substance and the brain. The nature of the COX-2 mRNA-positive cells in the leptomeninges will be identified in our future study.

Animals↗

Detection of stromal cells in peripheral blood progenitor cell collections from breast cancer patients.

Transplantation of growth factor-mobilized peripheral blood progenitor cells (PBPC) is widely used in the treatment of several neoplastic diseases. While in PBPC harvests the presence of several accessory immune and tumor cells has been documented, that of stromal cells has not been reported. In the present study, we investigated for the presence of stromal cells in growth factor-mobilized PBPC harvests from breast cancer patients. Low-density cells from PBCP harvests in culture gave rise to an adherent layer containing fibroblast-like and large flat round cells. These cells express positive immunofluorescence staining for collagen I, collagen III, fibronectin, VCAM-1 (CD106), ICAM-1 (CD54) and mesenchymal antigens recognized by monoclonal antibodies, SH2 and SH3. PBPC-derived stromal cells do not express antigens CD34, CD45 and CD14. Stromal cells were detected in the PBPC harvests of 11/14 patients (median 0.63%; range 0.02-2.32) and their concentration correlates with the number of CD34+ cells in PBPC.

Antigens, CD34↗

FtsN, a late recruit to the septum in Escherichia coli.

The localization of FtsN in Escherichia coli was inves tigated by immunofluorescence microscopy. FtsN is an essential cell division protein with a simple bitopic topology, a short N-terminal cytoplasmic segment fused to a large carboxy periplasmic domain through a single transmembrane domain. FtsN was found to localize to the septum in a ring pattern similar to that observed for FtsZ and FtsA, although the frequency of cells with rings was less. A MalG-FtsN fusion was also localized to the septum, indicating that the information for FtsN localization is supplied by its periplasmic domain. FtsN localization was dependent upon the prior localization of FtsZ and FtsA and required the function of FtsI and FtsQ. Consistent with FtsN functioning after FtsZ, Z rings were observed in a mutant depleted of FtsN.

Bacterial Proteins↗

Abilities to turn suddenly while walking: effects of age, gender, and available response time.

BACKGROUND: Falls may occur when an unexpected turn must be made quickly, in order to avoid colliding with an object in the gait path. Little is known about abilities, particularly about abilities of old adults, to turn suddenly. METHODS: Twenty young and 20 old (mean age 73.8) healthy and physically active adults, while walking straight ahead, were cued to make approximately a 90 degrees turn without advance knowledge of where the turn was to be made or whether it would be to the right or left. Subjects were given available response times (ART), the times between the cue to turn, and potential crossing of a specified forward limit line, of 375, 450, 600, and 750 ms. The rate of success (RS) in completing the turns as prescribed was determined. Regression analyses were used to estimate the additional ART that would be needed for other groups to achieve the same RS as did the young male subject group. RESULTS: For all ART, old subjects had a lower rate of success in completing the turns as prescribed than the young. At an ART of 375 ms, mean RS was 36% for the young and 6% for the old. The regression analyses suggested that, for RS from 30 to 95%, old adults needed 112 ms longer than young of corresponding gender to succeed as well. Females needed on the order of 50 ms longer ART than males of corresponding age. CONCLUSIONS: There are significant age and gender differences among healthy and physically active adults in the available response times they need when walking for successfully making sudden turns.

Adult↗

Temperature shift experiments with an ftsZ84(Ts) strain reveal rapid dynamics of FtsZ localization and indicate that the Z ring is required throughout septation and cannot reoccupy division sites once constriction has initiated.

FtsZ is an essential division protein in bacteria that functions by forming a ring at midcell that mediates septation. To further study the function of the Z ring the effect of a temperature-sensitive mutation, ftsZ84(Ts), on ring dynamics and septal progression was examined. Shifting a strain carrying an ftsZ84(Ts) mutation to the nonpermissive temperature led to loss of Z rings within 1 min. Septal ingrowth was immediately inhibited, and sharply demarcated septa, present at the time of the shift, were gradually replaced by blunted septa. These results indicate that the Z ring is required throughout septation. Shifting filaments to permissive temperature led to a rapid localization of FtsZ84 at regular intervals. Included in these localization events were complete and partial rings as well as spots, although some of these eventually aborted. These results reveal the rapid dynamics of FtsZ localization and indicate that nucleation sites are formed in the absence of FtsZ function. Interestingly, Z rings could not reform at division sites that were constricted although they could reform at sites that had not begun constriction.

Escherichia coli↗

Analysis of the interaction of FtsZ with itself, GTP, and FtsA.

The interaction of FtsZ with itself, GTP, and FtsA was examined by analyzing the sensitivity of FtsZ to proteolysis and by using the yeast two-hybrid system. The N-terminal conserved domain consisting of 320 amino acids bound GTP, and a central region of FtsZ, encompassing slightly more than half of the protein, was cross-linked to GTP. Site-directed mutagenesis revealed that none of six highly conserved aspartic acid and asparagine residues were required for GTP binding. These results indicate that the specificity determinants for GTP binding are different than those for the GTPase superfamily. The N-terminal conserved domain of FtsZ contained a site for self-interaction that is conserved between FtsZ proteins from distantly related bacterial species. FtsZ320, which was truncated at the end of the conserved domain, was a potent inhibitor of division although it expressed normal GTPase activity and could polymerize. FtsZ was also found to interact directly with FtsA, and this interaction could also be observed between these proteins from distantly related bacterial species.

Asparagine↗

Involvement of cyclooxygenase-2 in LPS-induced fever and regulation of its mRNA by LPS in the rat brain.

We previously showed that a febrile dose of lipopolysaccharide (LPS) in rats resulted in induction of cyclooxygenase-2 (COX-2) mRNA in brain blood vessels/leptomeninges and telencephalic neurons. To elucidate the causal link between fever and LPS-induced COX-2 mRNA, we experimentally modified one or the other of these parameters and examined their relation. 1) LPS-induced fever was suppressed by pretreatment with a COX-2-specific inhibitor. 2) Levels of COX-2 mRNA in the neurons and blood vessels 2.5 h after LPS administration were even higher in the inhibitor-pretreated rats (afebrile) than in vehicle-pretreated ones (febrile). 3) After repeated administration of LPS, rats became tolerant to LPS, in which state LPS induced neither fever nor COX-2 mRNA in blood vessels/leptomeninges. When rats had not completely established LPS tolerance, they showed various degrees of fever that were closely correlated with the level of COX-2 mRNA in blood vessels but not with that in neurons. 4) Urethan anesthesia reduced basal as well as LPS-induced COX-2 mRNA in telencephalic neurons, but the rats still responded to LPS with fever and induction of COX-2 mRNA in the blood vessels/leptomeninges. These results suggest that COX-2 induced in brain blood vessels/leptomeninges is involved in the molecular mechanism of LPS-induced fever.

Abdomen↗

[Clinical studies on pulpitis and periapical periodontitis caused by traumatic occlusion].

89 cases including 100 teeth with pulpitis and apical periodontitis caused by traumatic occlusion were clinically observed. All teeth are caries-free, no any dental disease, and no pocket formation. But there is a distinct evidence of marked occlusal trauma, such as premature contact and occlusal interference. The single-root teeth are usually involved. When subjected to vitality testing the teeth associated with the periapical lesions sometimes yield positive response (about 30%). The result of investigation endodontic treatment demonstrated that the presence of predisposing factors of trauma from occlusion led to decrease of endodontic success.

Adolescent↗

[The effect of artificial traumatic occlusion on the pulp and periodontium in rat molars].

In order to study relationship between the period of occlusal trauma and pulpal and periodontal tissues, 44 rats were used in experimental occlusal trauma. The pulpal and periodontal tissues of rat molars were observed by histological examination and micrographic examination. The results showed that the damage of pulp became more serious as time went on, but periodontium appeared adaptive changes. The same changing area in periodontal tissues were observed between histological section and micrographic film. The results provide experimental evidences for the pathology and pathogeny of pulpitis and perioapical periodontitis caused by occlusal trauma.

Animals↗