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Biomedical subjects

C Cao

Publications and source records attributed to C Cao.

At least 127 records · Page 7Linked to original sources
PubMed1995

[Alkaline phosphatase levels in gingival crevicular fluid of periodontitis before and after periodontal treatment].

Gingival crevicular fluid (GCF) samples were collected from 204 teeth from 35 subjects, including 8 rapidly progressive periodontitis (RPP), 14 chronic adult periodontitis (CAP), 7 marginal gingivitis (MG) and 6 healthy subjects (H). The results of alkaline phosphatase (ALP) examination indicated that the ALP levels from CAP and RPP patients were significantly higher than those from H subjects and MG patients. The ALP levels were closely related to the amount of GCF flow and various clinical periodontal parameters, especially to probing depth and attachment loss. The ALP levels and the various clinical parameters decreased significantly after periodontal therapy. The present study suggests that the measurement of GCF--ALP could be an useful adjuctive criterion for detection of periodontal inflammatory status and extent of tissue destruction.

Adult↗
PubMed1995

[Clinical evaluation of force-sensitive probe in the examination of tooth sensitivity].

Two methods were tested for measuring the sensitivity of dentin to mechanical (force-sensitive probe) and cold air stimuli. Of the 212 sensitive teeth in 71 patients, 94.8% were sensitive to probe, with a mean threshold of 22.79g; 89.6% were sensitive to cold air. These two methods were significantly correlated (P < 0.001). The occlusal sites were less sensitive than the buccal sites measured by probe and cold air. It suggests that force-sensitive probe is a simple, quantitative method of measuring tooth hypersensitivity.

Adult↗
PubMed1994

Specific detection of a verotoxin 2 variant, VT2vp1, by a bead-enzyme-linked immunosorbent assay.

A bead-enzyme-linked immunosorbent assay to specifically detect a Verotoxin 2 variant, VT2vp1, was developed. The sensitivity of the bead-ELISA was 200 pg/ml of the purified VT2vp1 and it did not react with 20 ng/ml of the purified VT2. The specificity of the bead-ELISA was examined with 107 strains of Verocytotoxin-producing Escherichia coli that include VT1-, VT2-, VT2vha-, VT2vhb- and VT2vp1-producing E. coli, and only VT2vp1-producing E. coli that were confirmed by VT2vp1-specific polymerase chain reaction gave positive results. It was noted that all 58 VT2vp1-producing E. coli strains were from pigs, but not from cows and humans.

Animals↗
PubMed1994

Construction of mutant genes for a non-toxic verotoxin 2 variant (VT2vp1) of Escherichia coli and characterization of purified mutant toxins.

The gene encoding a Verotoxin 2 variant, VTvp1, was mutated by oligonucleotide-directed site-specific mutagenesis. Among 6 mutant toxins encoded by the mutated genes, E167Q-R170L (glutamic acid at position 167 and arginine at position 170 from N-terminus of the A subunit were replaced by glutamine and leucine, respectively) was found to have markedly decreased activities; inhibition of protein synthesis, Vero cell cytotoxicity and mouse lethality of the purified E167Q-R170L were 1/1,900, 1/125,000 and 1/2,000, respectively, of those of the purified wild-type VT2vp1. Since the antigenic property of the E167Q-R170L was demonstrated to be similar to that of the wild-type VT2vp1 by Ouchterlony double gel diffusion test and by neutralization test of Vero cell cytotoxicity of the VT2vp1, a possibility to use the mutant VT2vp1, E167Q-R170L, as a toxoid is discussed.

Animals↗
PubMed1994

[The upstream sequence of cholera toxin B subunit gene: effect on CTB expression].

In this work, we have studied the effect of cholera toxin A structure gene on the expression of the distal ctxB gene by the methods of deletion and frame-shift mutation. The results showed that: The expression level of Plasmid pUC19CTB, which was constructed by cloning the XbaI-EcoRI restriction fragment into pUC19 and ctxA gene was out-frame with lacZ' gene, is about 30 micrograms/ml; If a frame shift mutation was introduced at XbaI site of pUC19CTB so that the cholera toxin A gene was inframe with lacZ' and could be translated, the expression level of ctxB was decreased to 12 micrograms/ml; When A further deletion from XbaI to ClaI of cholera toxin A gene (about 550bp) was made and ctxA was outframe with LacZ', ctxB expression was decreased two fold compared to pUC19CTB; If the ctxA was inframe with LacZ' so ctxA gene could be translated, the expression level of CTB is much lower than the plasmid outframe with lacZ'. These observations could not be explained by the current knowledge about genetical regulation of cholera toxin operon. The promoter we found located in the cholera toxin A subunit gene, which is responsible for the expression of cholera toxin B subunit, may answer the question why the 550bp non-coding sequence could enhance the expression of cholera toxin B subunit.

Base Sequence↗
PubMed1993

Purification and some properties of a Vero toxin 2 (Shiga-like toxin II) variant (SLT-IIva) of Escherichia coli isolated from infantile diarrhea.

A variant of Vero toxin 2 (VT2), or Shiga-like toxin II (SLT-II) was purified from a cloned strain of Escherichia coli carrying a gene that encodes SLT-IIva, which is most closely related to SLT-IIv (VT2vp, VTe) in its nucleotide sequence. The purified SLT-IIva showed a slight difference from the purified SLT-IIv (VT2vp) in mobility on polyacrylamide gel disc electrophoresis and SDS-polyacrylamide gel slab electrophoresis and in pI, but both showed a similar potency in biological activities. Ouchterlony double diffusion test revealed that the purified SLT-IIva and SLT-IIv (VT2vp) formed a spur against anti-SLT-IIva and anti-SLT-IIv (VT2vp) antisera.

Animals↗
PubMed1993

Probenecid-resistant J774 cell expression of enhanced organic anion transport by a mechanism distinct from multidrug resistance.

Macrophages possess organic anion transporters that carry membrane-impermeant fluorescent dyes, such as lucifer yellow (LY) and carboxy-fluorescein, from the cytoplasm into endosomes and out of the cells. Probenecid, an organic anion transport inhibitor, blocks these processes. Prolonged incubation of J774 cells in medium containing 2.5 mM probenecid eventually kills most of these cells. To identify J774 variants that express increased organic anion transport activity, we selected probenecid-resistant (PBR) J774 cells by growing them in medium containing increasing concentrations of probenecid. When PBR and unselected J774 cells were loaded with LY by ATP4- permeabilization, the amount of LY accumulated by the PBR cells was about half that in the unselected cells. This difference was abolished by adding 10 mM probenecid to the medium in which the cells were loaded, suggesting that the diminished LY accumulation in PBR cells was due to enhanced LY secretion and that the PBR cells expressed increased organic anion transport activity. Direct comparison of LY efflux from J774 and PBR J774 cells showed a faster initial rate of secretion of LY from PBR J774 cells than from unselected J774 cells. To determine whether LY efflux is mediated by P-glycoprotein, we compared LY efflux in unselected J774 cells, PBR J774 cells, and multidrug-resistant J774 cells (J7.C1). LY efflux from J7.C1 cells was not sensitive to verapamil, which inhibits multidrug-resistance transporters, and reverses the multidrug-resistant phenotype of J7.C1 cells. The rates of LY efflux from unselected J774 and J7.C1 cells were virtually identical.(ABSTRACT TRUNCATED AT 250 WORDS)

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

[Androgen receptors in muscles mediate the trophic effect of testosterone on axotomized neurons].

In order to further explore the hypothesis that muscles are the primary action site for testosterone, the present study examined the effect of androgen receptor blockade in effector muscles on the efficacy of testosterone in preventing neuronal cell loss following axotomy. Hydroxyflutamide (HF), an androgen antagonist that acts competitively at the hormone receptor site, was administered into muscles of the tongue when animals were treated with testosterone following unilateral transection of the hypoglossal and facial nerves. The ability of testosterone to prevent neuronal cell loss in the axotomized hypoglossal and facial motor nucleus was examined. The results demonstrated that hydroxyflutamide completely negates the survival-promoting effect of testosterone on axotomized motoneurons.

Animals↗
PubMed1991

[Treatment of Hodgkin's disease. National Protocol of Antineoplastic Drugs: preliminary report].

We report preliminary results of treatment of Hodgkin disease according to the National Protocol on Antineoplastic Drugs. 37 males and 22 females with a median age of 34 years (range 16 to 76) were treated. Patients with stages I or II received radiotherapy alone or chemotherapy (C-MOPP) followed by radiotherapy. Patients with stages III or IV received radiotherapy and chemotherapy or alternating courses of C-MOPP and ABVD. Complete remission was observed in 74% of 39 patients completing full therapy. Complete remission was more common in patients with nodular sclerosis without B symptoms and under 45 years of age. Actuarial survival at 22 months was 79%, significantly higher for patients with nodular sclerosis compared to patients with lymphocytic depletion. Different treatments in patients at stages I and II or III and IV gave comparable results. Complications included infection with the Chickenpox-Zoster virus, pneumonia and fever of unknown origin. Mortality was associated to older age, complications of treatment or failure to comply with therapy.

Actuarial Analysis↗
PubMed1991

[Malignant lymphomas. Preliminary report of the National Protocol of Antineoplastic Drugs].

The first results of the management of adult non-Hodgkin lymphoma according to the National Protocol are reported. 164 pts (71 female and 93 male), aged 50 (range 15 to 79 years) were included. 89 pts had lymphomas with intermediate, 34 with low and 24 with high grade malignancy. 65% had advanced stages (III and IV). In the low grade malignancy group 38% were in complete remission and actuarial survival at 20 months was 80%. In the intermediate grade group, stages I and II the corresponding values were 79 and 85%; in the intermediate grade stages III and IV, 58 and 69%, and in the high grade group 61 and 77%. Bone marrow toxicity and infections were the main complications. 32 pts have died, 10 of them with drug toxicity complications.

Adolescent↗
PubMed1991

[Pharmacological studies on Bombyx mori L].

The toxicity of the Bombyx mori extract is very low. It can promote the growth of under-aged male mice, and increase markedly the weight of the prostate glands, seminal vesicles and preputial glands in castrated rats of mice. The results of the experiments have shown that Bombyx mori has androgen-like action.

Animals↗
PubMed1991

Pharmacokinetics of vancomycin in patients undergoing hemodialysis with polyacrylonitrile.

The pharmacokinetics of vancomycin in patients undergoing dialysis with cuprophane membranes are well known, however little has been reported of the use of polyacrylonitrile membranes in dialysis. We studied, in a crossover design, eight dialysis patients (7 men, 1 woman) aged 30 to 66 years who prospectively received 1 gram of vancomycin i.v. before first dialysis and were subsequently hemodialyzed with cuprophane every second day for a total of three times. A month later trial was repeated using polyacrylonitrile. A mono-compartment model was used to calculated pharmacokinetic parameters. Mean +/- standard deviation of vancomycin clearance varied from 5.2 +/- 2.1 ml/min in the interdialysis period to 9.7 +/- 2.7 ml/min during dialysis with cuprophane and to 58.4 +/- 15.6 ml/min during dialysis with polyacrylonitrile (p less than 0.001). Vancomycin half-life varied from 71.5 +/- 23.0 to 35.9 +/- 9.8 and to 6.1 +/- 1.4 hours, respectively (p less than 0.001). Fractional removal of vancomycin increased from 4% using the cuprophane dialyzer to 34% using the polyacrylonitrile dialyzer (p less than 0.001). Serum vancomycin levels at 100 and 168 hours were higher with cuprophane than with polyacrylonitrile (7.0 +/- 2.2 vs 3.9 +/- 1.2 micrograms/ml) (p less than 0.001). Moreover, the mean levels at 100 hours were suboptimal on polyacrylonitrile. Approximately 208 +/- 53 mg of vancomycin were removed during one polyacrylonitrile dialysis. Thus, those patients who undergo dialysis with polyacrylonitrile and are treated with vancomycin may need supplementary doses post dialysis or to lessen dosage intervals than those traditionally used for dialysis patients since clearance of the drug is significantly higher than with cuprophane dialyzers. Continuous monitoring of vancomycin levels is also recommended.

Acrylic Resins↗
PubMed1991

[Determination of serum antibody against Bacteroides gingivalis from rapidly progressive periodontitis and juvenile periodontitis patients].

Bacteroides gingivitis (Bg) is one of the major pathogens associated with periodontitis. This is the first report in China on serum antibody level against Bg from patients with rapidly progressive periodontitis (RPP) and juvenile periodontitis (JP) using ELISA method. 21 RPP patients, 20 JP patients and 30 healthy subjects (H) were involved in this study. The results showed that the ratio of positive antibody response was 100% in RPP, 80% in JP and 30% in control group. The antibody response in both RPP and JP groups were significantly greater than that in healthy group (P less than 0.001). The difference between RPP and JP groups were also statistically significant (P less than 0.05).

Adolescent↗
PubMed1990

[Treatment of acute lymphoblastic leukemia in adults: preliminary report of the national protocol on antineoplastic drugs].

We report preliminary results from a national protocol for treatment of acute lymphoblastic leukemia. 44 patients, 15 females and 29 males with age range 15 to 65 years (median 27) were treated and followed for 22 months. Complete remission was observed in 33 (77%) of 43 patients with a known induction result. Remission was 100%, 86% and 61% for low (3), medium or high risk patients (p = 0.03). Complete remission occurred more often in patients with WBC less than 35,000 or granulocyte counts greater than 100. Actuarial survival rate at 22 months was 60% overall and 100%, 64% and 50% for the low, intermediate and high risk groups, respectively (NS). Death occurred in 16 patients, 5 during induction, 3 during complete remission, 6 during relapse and 2 after induction failure. Infections were the main cause of death in all groups.

Actuarial Analysis↗
PubMed1990

[Treatment of acute non-lymphoblastic leukemia in adults. Preliminary report from the national protocol on antineoplastic drugs].

After a follow up of 22 months we report results of treatment on 44 patients (22 males), aged 16 to 63 years, with acute non lymphoblastic leukemia. Complete remission was obtained in 22 patients. This was significantly more frequent in patients under 40 years of age with white cell counts under 35,000 and without metabolic complications nor disseminated intravascular coagulation before treatment. Delaying chemotherapy for 5 days after diagnosis was also associated to a better prognosis. Overall actuarial survival rate was 37% at 15 months, 55% for those experiencing a first remission. A total of 25 patients [corrected] have died, 15 during induction of therapy, 7 after complete remission and 3 after failure of induction. Infections are the main cause of death during induction, with a high lethality for sepsis (33%) and pneumonia (40%).

Actuarial Analysis↗
PubMed1988

In-vitro activity and beta-lactamase stability of LY163892.

LY163892 is a new orally absorbed carbacephem. It inhibited Streptococcus pyogenes and Str. pneumoniae at less than or equal to 1 mg/l, but was less active against group B streptococci and groups C, F, G and bovis streptococci with MICs of 1 to 2 mg/l for most but as high as 8 mg/l for some isolates. MIC90 of methicillin-susceptible Staphylococcus aureus was 8 mg/l, but greater than 128 mg/l for methicillin-resistant staphylococci. LY163892 had activity similar to cefaclor and cephalexin with MIC90 values of 16 mg/l for Escherichia coli, 8 mg/l for Klebsiella pneumoniae, Proteus mirabilis, Yersinia enterocolitica, but was more active against Haemophilus influenzae, and Branhamella catarrhalis. It had no activity against Enterobacter, Providencia, Serratia, and Pseudomonas and Bacteroides spp. LY163892 was more rapidly lytic than cephalexin. It was hydrolyzed by a number of plasmid and chromosomal beta-lactamases. For TEM-1, the Km = 354.7 microM, Vmax = 2.5 microMoles/min/mg of protein, P99 Km = 24.3 microM, Vmax = 28.9 microM/min/micrograms of protein, Staph. aureus PC Km = 47.4 microM, Vmax = 2.7 microMoles/min/mg of protein. Overall it had beta-lactamase stability similar to cefaclor, less than cephalexin, and markedly less than cefuroxime.

Amoxicillin↗
PubMedDate not supplied

Molecular electronegative distance vector (MEDV) related to 15 properties of alkanes.

Several quantitative structure-property relationship (QSPR) models between 15 basic physical properties or thermodynamic functions of alkanes and their molecular electronegative distance vectors (MEDV) are developed. For six of the properties-boiling point (BP), density (D) at 25 degrees C, refraction index (RI) at 25 degrees C, critical temperature (CT), critical pressure (CP), and surface tension (ST) at 20 degrees C-logarithmic models are found to give better results than conventional (linear) models since the values of these properties all tend to a limit with increasing carbon chain length. All models are created using multiple linear regression (MLR). Conventional models are proposed for the remaining nine physical properties or thermodynamic functions: molar volume (MV) at 20 degrees C, molar refraction (MR) at 20 degrees C, heat capacity (HC) at 300 K, enthalpy (E) at 300 K, heats of vaporization (HV) at 25 degrees C, heat of atomization (HA) at 25 degrees C, standard heat of formation (HF) at 25 degrees C, heat of formation in liquid (HFL) at 25 degrees C, and heat of formation in gas (HFG) at 25 degrees C.

Journal Article↗