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Biomedical subjects

M Cao

Publications and source records attributed to M Cao.

At least 55 records · Page 3Linked to original sources
PubMed1997

Purification and characterization of myofibril-bound serine proteinase from carp Cyprinus carpio ordinary muscle.

1. A novel myofibril-bound serine proteinase (MBP) has been purified from ordinary muscle of the carp Cyprinus carpio. 2. It was solubilized from the myofibril fraction with acid treatment (under the conditions of 0.6 M KCl, pH 4.0), then purified by column chromatographic steps on Ultrogel AcA 54, and Arginine-Sepharose 4B. 3. The purified enzyme revealed a single protein band on SDS-PAGE, and its molecular mass was estimated to be 30 kDa by SDS-PAGE and gel filtration. 4. The optimum pH and temperature of the enzyme were 8.0 and 55 degrees C, respectively, when Boc-Phe-Ser-Arg-MCA and casein were used as substrates. 5. The enzyme hydrolyzed Boc-Gln-Arg-Arg-MCA most rapidly, and also hydrolyzed the substrates for trypsin-type proteinase, but not for chymotrypsin. The enzyme was inhibited by serine proteinase inhibitors such as DFP, STI and leupeptin. These results suggested that the enzyme was a trypsin-type serine proteinase. 6. Boc-Phe-Ser-Arg-MCA hydrolyzing activity of the purified enzyme was reduced by addition of NaCl, but the caseinolytic activity and Boc-Phe-Ser-Arg-MCA hydrolyzing activity of the partially purified enzyme were activated by NaCl.

Amino Acid Sequence↗
PubMed1997

[Protective effects of nimodipine on brain edema induced by pertussis bacilli in rats].

The changes of brain water content and Evan blue(EB) were investigated on the model of infection brain edema induced by Pertussis Bacilli(PB) in 72 rats. Nimodipine was admenistred to show its effect on the PB induced brain edema. The experiment results showed that the water content and EB content in the PB group were significantly increased than those normal group and normal saline group at 30 min, 4 hours and 24 hours after the injection of PB (P < 0.05). Nimodípine could significantly reduce brain water content and EB content, so that brain edema was attenuated. It indicates that nimodipine showed advantage to treatment of PB brain edema.

Animals↗
PubMed1996

Detection of right ventricular ischaemia during coronary surgery by means of a right precordial lead.

This study was designed to determine the intra-operative incidence of right-sided ventricular ischaemia and any association with left ventricular ischaemia. In 60 patients, undergoing coronary artery bypass grafting surgery, a right-sided precordial lead V5R was used. ST segment deviation of more than 1 mm in V5R was considered significant for myocardial ischaemia. Right ventricular ischaemia occurred in 14 patients (23.3%) but was not associated with left ventricular inferior wall ischaemia. In 4 patients (6.6%) presenting with right ventricular ischaemia, ischaemia of the left inferior wall also developed but in all cases was transient and disappeared by the end of surgery. No myocardial infarction was detected in the post-operative period. The present study showed that the use of a right-sided lead may improve intra-operative electrocardiographic monitoring, by revealing ischaemia in those patients in whom ECG abnormalities were not detected by conventional leads. The transient right ventricular ischaemia recorded in this study was probably related to a reduced hypothermic protection of the right ventricle during aortic cross clamping.

Adult↗
PubMed1995

Reduced expression of the molecular markers of dopaminergic neuronal atrophy in the aging rat brain.

Expression of mRNAs encoding the dopamine transporter (DAT) and tyrosine hydroxylase (TH) in dopaminergic neurons of the substantia nigra (SN) was examined in young and aged Fischer 344 rats by in situ hybridization. Quantitative analysis revealed a statistically significant decline in both DAT and TH mRNA expression in 24-month-old rats in comparison to 6-month-old rats. In addition, it was noted that DAT mRNA expression tended to decrease by 18 months, while TH mRNA reduction did not occur until 24 months. The age-related loss of DAT and TH mRNA expressions was accompanied by diminished expression of mRNA for a neuronal growth-associated protein GAP-43, but not for SCG10 or alpha 1-tubulin. The loss of GAP-43 mRNA became evident when both DAT and TH gene expression declined with advanced age. Our findings indicate that DAT may be a marker of atrophy in dopamine neurons during normal aging.

Aging↗
PubMed1995

Preparation and characterization of monoclonal antibodies against aflatoxin B1.

Five hybridoma cell lines producing monoclonal antibodies (MAb) against Aflatoxin B1 (AFB1) were established after fusion of mouse myeloma cells (SP-2/O-Ag-14) with spleen cells isolated from male BALB/c mice immunized with AFB1-BSA conjugate. Among these, one MAb, designated AFB1-2H8, was of the subtype IgG3 and the acidic fluid of which gave high dilution titers (1:5 x 10(5). The sensitivity of a competitive inhibition enzyme immunoassay (CIEIA) using AFB1-2H8 for AFB1 demonstrated that the linear range was 0.5-50 ng/ml and the minimum detectable concentration of AFB1 was 0.01 ng/ml. The specificity of the MAb was determined and showed no significant crossreaction with any of the metabolites tested. So th-- MAb and the CIEIA described may be useful in the detection of AFB1 in food and feed.

Aflatoxin B1↗
PubMed1993

Cloning, expression, and characterization of Cryptococcus neoformans dihydrofolate reductase.

The Cryptococcus neoformans dihydrofolate reductase (DHFR) gene has been isolated from cDNA and genomic DNA libraries. The 690-base pair coding sequence codes for a 25,152-Da protein, which is the largest monofunctional DHFR yet reported. The gene contains two introns, and several putative regulatory sequences have been identified. The coding sequence was placed in a pUC-based expression vector, which expresses C. neoformans DHFR in Escherichia coli at a level of about 5% of the total soluble extract. The expressed DHFR was purified to homogeneity by methotrexate-Sepharose affinity chromatography, followed by anion exchange chromatography on Q-Sepharose. On SDS-polyacrylamide gel electrophoresis, the purified enzyme migrates as a single protein with apparent mass of 28 kDa. The molecular weight, as determined by electrospray mass spectral analysis, and the amino-terminal sequence are in accord with what was predicted from the DNA sequence. Steady state kinetic parameters, effects of pH, salts, and inhibition constants of several anti-folates have been determined.

Amino Acid Sequence↗
PubMed1992

Enhancement of the protective effect of inactivated influenza virus vaccine by cytokines.

The authors examined whether or not cytokines in conjunction with inactivated influenza virus vaccine enhance protection from influenza virus infection in mice. Mice were infected with influenza virus A/PR/8/34 (PR/8) at 10 LD50 by nebulizer after intranasal administration of the cytokine and the vaccine. The survival rate of the group which received both the vaccine and mouse recombinant interferon-beta (MuIFN-beta; 1 x 10(4) IU/mouse) or mouse recombinant interferon-gamma (MuIFN-gamma; 1 x 10(4) IU/mouse) was significantly higher than that of the control group given the vaccine alone. These results show that MuIFN-beta and MuIFN-gamma have an adjuvant effect on this vaccination. In contrast, human recombinant interleukin-2 (HuIL-2) and human recombinant tumour necrosis factor (HuTNF) did not have an adjuvant effect. In order to examine the mechanism of the enhancing effect of MuIFN-gamma on this vaccination, we determined the specific IgA and IgG antibodies present in bronchoalveolar lavage fluid (BALF) and serum, and haemagglutination inhibition (HI) antibody in serum. In the early stage of infection, the titres of IgA and IgG antibodies in the combined group receiving the vaccine with MuIFN-gamma showed a tendency to be higher than those in the group given the vaccine alone. In the late stage of infection, the titre of HI antibody in the group given the vaccine with MuIFN-gamma was significantly lower than that in the group given vaccine alone. It can be concluded from these results that a part of the adjuvant effect of MuIFN-gamma on this vaccination was due to an increase in production of antibodies which neutralized the virus in the lesion.

Animals↗
PubMed1992

Treatment of Staphylococcus aureus nasal carriers in CAPD with mupirocin.

We have studied the efficacy of topical Mupirocin for elimination of Staphylococcus aureus (Staph. aureus) nasal carriage in CAPD patients. Staph. aureus nasal carriers in our CAPD program were randomized to one of two groups: Group 1, treated with Mupirocin, and Group 2, treated with neomycin sulphate nasal ointment. The prevalence of Staph. aureus nasal colonization was 44% for patients (24/54) and 17% for dialysis partners (5/29). Group 1 included 11 patients and 1 partner, and Group 2, 8 patients and 2 partners. In Group 1, the eradication rate was 100%, and the recolonization rate was 0, 8, 41, 55 and 66% at 1, 2, 3, 6 and 10 months. In Group 2, the eradication rate was 40%, with a recolonization rate of 0.25 and 75% at 1, 2 and 3 months. Re-treatment with mupirocin was successful in 66% of the cases, compared to 20% for neomycin. The MIC90 of mupirocin for Staph. aureus was 0.5 mcg/mL, with an increase to 4 mcg/mL towards the end of the study. During the study period, there was a very low incidence of Staph. aureus peritonitis or catheter-related infections in patients treated with mupirocin. Secondary effects of mupirocin were negligible. Mupirocin is more effective than neomycin sulphate for the elimination of Staph. aureus nasal colonization in patients undergoing CAPD. Periodic re-treatment is frequently necessary, given the significant recolonization rate.

Administration, Topical↗
PubMed1991

Low frequency hearing threshold determination in newborns, infants and mentally retarded children by middle latency responses.

Middle latency (10-50 ms) responses (MLR) evoked by tone-pips (1,000 Hz 500 Hz) and early (0-10 ms) auditory evoked potentials (EAEP) evoked by chicks were recorded on 68 newborn babies (premature or at term), infants and children, some with central nervous system or psychiatric disorders, who had normal or impaired hearing. MLR were obtained either during sleep, chloral-hydrate sedation or ketamine anesthesia. Thresholds estimated from MLR and EAEP were compared to those from subsequent psychoacoustic pure tone testing. We confirm that MLR provide good threshold estimates for hearing in the low frequency range, whereas click evoked EAEP are good threshold indicators only for high frequencies.

Acoustic Stimulation↗
PubMed1991

[A comparison between antigliadin antibodies and blood xylose in celiac disease].

We have compared serum antigliadin antibodies (AGA) with xylose absorption test in diagnosis and follow-up of pediatric celiac disease. Three groups of children were investigated: celiacs, affected by other gastrointestinal disease, healthy controls. On gluten diet AGA IgA, IgG and xylose test were abnormal in all celiac children. After only three months of gluten-free diet, abnormal AGA IgA values were found in 3%, AGA IgG in 63%, xylose test in 28% of children. Normal values for AGA IgA and IgG and for xylose test were found between 7 and 20 months. On challenge, after 1-4 months of gluten diet, abnormal AGA IgA and IgG values were found in 90% of cases, xylose test only in 27%. As far as the children with other gastrointestinal disease are concerned, 2% had abnormal values for AGA IgA, 22% for AGA IgG and 42% for xylose test. All healthy children had normal AGA IgA, IgG values and xylose test. Our date show AGA IgA the most specific laboratory test, among these investigated, for diagnosis and follow-up of celiac disease.

Adolescent↗
PubMed1991

Establishment and preliminary application of spermidine radioimmunoassay with 125I-labelled monoclonal antibody and solid phase antigen.

Purified anti-spermidine monoclonal antibody was labelled with radioactive iodine by the Iodogen method and spermidine-bovine serum albumin (SPD-BSA) conjugate was used to coat polystyrene beads as solid phase antigen. The new solid phase 125I-labelled spermidine radioimmunoassay (RIA) depends on the competition between spermidine in the sample and the solid phase antigen for the limited amount of 125I-labelled monoclonal antibody. The sensitivity of this assay was 10 ng/ml higher than that of liquid RIA for spermidine with 14C-labelled spermidine. The coefficients of variation (CV) within and among batches were 4% and 13% respectively. The sample-batch capacity was increased from 20 (liquid RIA with 14C-labelled spermidine) to 150-200 by using this method. Because of its simplicity, the solid phase RIA kit is very convenient for population survey. This RIA could be used to determine spermidine in saliva for the diagnosis of precancerous lesions. In a preliminary study saliva spermidine levels in different populations were measured among 130 normal subjects, 202 esophageal epithelial hyperplasia cases treated with anti-tumor B for 5 years, 207 esophageal epithelial hyperplasia cases as control, and 55 esophageal cancer patients. The levels were 1,795 +/- 1,481, 3,470 +/- 6,981, 9,753 +/- 17,641 and 18,090 +/- 21,509 ng/ml, respectively, with the saliva spermidine levels in precancerous and cancer patients being significantly higher than that of normal subjects (P less than 0.001); the level in patients treated with anti-tumor B was significantly lower than that of controls (P less than 0.001). This decreased saliva spermidine content was coincident with the 47.3% reduction of canceration rate seen in precancerous patients after a 5-year treatment with anti-tumor B.

Antibodies, Monoclonal↗