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At least 685 records · Page 38Linked to original sources
PubMed2000

[Evaluation of cariogenic potential of Streptococcus mutans isolated from caries-free and -active persons: adherence properties to saliva-coated hydroxyapatite].

OBJECTIVE: In this study, authors used saliva-coated hydroxyapatite to simulate tooth surface in oral cavity to evaluate adherence of different Streptococcus mutans isolated from caries-free and -active persons to saliva-coated hydroxyapatite. METHODS: Streptococcus mutans isolated from people with different carious experiences were divided into two groups: the caried-free group (DMFS = 0) including 19 persons and the caries-active group (DMFS > or = 6) including 40 persons. Totally 105 genotype Streptococcus mutans strains were obtains, including 22 strains from the caries-free group, and 83 strains from the caries-active group. The adhering properties of Streptococcus mutans (serotype c) strains were investigated, and different adhering properties were compared between the caries-free group and the caries-active group in order to find the correlationship between carious experiences and adhering properties of Streptococcus mutans. Saliva-coated hydroxyapatite was used to simulated tooth surface in oral cavity. Streptococci mutans were cultured in TPY liquid medium containing 3H-TDR in the same radioactive concentration. After being cultured in an anaerobic incubator for 18 hours, Streptococci mutans were radiolabelled by 3H-TDR. Saliva-coated hydroxyapatite and bacterial liquid(BSA = 0.52) were mixed for 90 minutes. Samples were assayed by using liquid scintillation counter, and binding abilities of strains were evaluated by the count per minute(cpm). RESULTS: Binding abilities of strains were significantly different in two groups, Caries-active people harbored more Streptococci mutans with high binding abilities(cpm > 2000) than caries-free people did(P < 0.05). The binding abilities to saliva-coated hydroxyapatite were different between strains of differing genotypes isolated from the same person. Each person always harbored one or two strains with high binding abilities(cpm > 2000) in the caries-active group. CONCLUSION: 1. Different genotypes have different adhering properties. 2. In caries-active group, different genotype strains have synergic effects, and adhesion of high binding ability strains cause caries susceptibility. 3. The differences in binding properties of isolates might relate to differences in carious experiences.

Bacterial Adhesion↗
PubMed2001

VEGF induced hyperpermeability in bovine aortic endothelial cell and inhibitory effect of salvianolic acid B.

AIM: To examine the effect of recombinant human vascular endothelial growth factor (VEGF) on the low density lipoprotein (LDL) permeability of bovine aortic endothelial cells (BAEC) and the inhibitory effect of salvianolic acid B in vitro. METHODS: The confluence BAEC monolayers were cultured with normal medium and with medium containing VEGF or salvianolic acid B at various concentrations and for various time periods. The iodine labeled LDL flux across the monolayers was then performed, and radioactivity was measured by SN-695 automatic liquid scintillation counter. RESULTS: Addition of purified human recombinant VEGF to the BAEC monolayers could significantly increase the permeability of the monolayer to 125I-LDL (P < 0.01). The permeability-increasing activity of VEGF on the BAEC monolayers was both dose and time dependent. Salvianolic acid B could markedly inhibit the VEGF-induced hyperpermeability in BAECs (P < 0.01). CONCLUSION: VEGF plays a role in the formation and development of atherosclerosis, and salvianolic acid B has inhibitory effect on VEGF-induced hyperpermeability in BAEC.

Animals↗
PubMed2000

[Quantitative assay of telomerase activity in head and neck squamous cell carcinoma].

OBJECTIVE: To detect and quantify telomerase activity in tissues from head and neck squamous cell carcinoma (HNSCC), and to explore whether the levels of telomerase activity can be a useful marker for cancer risk assessment in HNSCC. METHOD: The levels of telomerase activity of 55 fresh specimens obtained from 25 patients with HNSCC were detected by the method of telomeric repeat scintillation radioactive count, including 25 primary tumors, 7 samples of neck metastases and 23 corresponding normal tissues as control. In 7 patients, both primary and metastatic tumors were obtained. The levels of telomerase activity were determined with a liquid scintillation counter. The basic principle of the technique is that a G-rich oligonucleotide strand of telomeric sequence is used as primer, 3H-dTTPs are incorporated into the products while telomerase elongates the primers, and then free 3H-dTTPs are removed by rinsing step, finally radioactive count per minute (cpm) of products is detected, and the levels telomerase activity can be evaluated according to the value (cpm). RESULT: 1. The levels of telomerase activity (cpm) in tissues with HNSCC were significantly higher than those in the normal tissues (P < 0.05); 2. The levels of telomerase activity in the primary tumors were higher than those of their neck metastases, but the difference was not statistical significance (P > 0.05); 3. The levels of telomerase activity in the neck metastases were remarkably higher than those in the normal tissues (P < 0.05). CONCLUSION: 1. Detection of telomerase activity in HNSCCs can be a useful marker for cancer assessment. 2. To quantify telomerase activity may have clinical diagnostic value for HNSCC. 3. The levels of telomerase activity in the metastatic lymph nodes were higher.

Carcinoma, Squamous Cell↗
PubMed2000

[Effects of epidermal growth factor on wound healing of penetrating keratoplasty in rabbits].

OBJECTIVE: To observe the effects of epidermal growth factor (EGF) on wound healing of the penetrating keratoplasty(PKP) in rabbits. METHODS: Twelve rabbits (24 eyes) were stratified randomly divided into 6 groups and underwent penetrating keratic autoplasy. Liquid scintillation counter was used to measure the incorporation rate of 3H-TdR. Pressure-detector was used to survey the intensity of keratic wound healing. AgNORs staining was used to count the fibroblast cells at keratic wound. HE staining, VG staining, AgNORs staining and transmission electron microscopy were used to observe the morphological changes of keratic wound. RESULTS: 1 The intensity of EGF group on 8 days, 14 days and 21 days after PKP was significantly higher than that of the control group(P < 0.01). 2. The incorporation rate of 3H-TdR in wound healing the EGF group on 14 days and 21 days was obviously higher than that of the control group(P = 0.01). 3. The number of fibroblast cells of EGF were more than that of the control group(P < 0.01) in 8 days. CONCLUSION: EGF can promote the wound healing in rabbits after PKP.

Animals↗
PubMed2003

[An in vitro nuclear run-on assay for nuclear function of angiogenin].

A sensitive and quantitative in vitro analysis method was established to detect the nascent RNAs stimulated by angiogenin using the nuclei isolated from human umbilical vein endothelial cells (HUVE). Angiogenin was mixed with nuclei in the reaction buffer, then transcription was initiated by adding the NTPs mixture. The RNA products were measured quantitatively by [alpha-(32)P]CTP incorporation with a liquid scintillation counter, either after removing free isotope by using spin column, or cutting the electrophoresis lane and counting after autoradiography. It was found that the optimum reacting temperature was 30 degrees, the most suitable reaction time was 30 min for this system, and the transcription enhancement activity of angiogenin was dose-dependent with the feasible concentration being 1 mg/L. Higher concentration of angiogenin degraded the RNA products in the system, suggesting that there is a mechanism to control the entry and accumulation of angiogenin in the target cells, which ensured angiogenin to play its role properly in the cells. Based on the evidence that angiogenin bound to DNA in nucleolus and enhanced RNA transcription, it was proposed that angiogenin might act as a trans-acting factor in nucleus to regulate RNA transcription, and inhibition of angiogenin-stimulated RNA transcription might be a promising target for screening anti-angiogenesis inhibitor.

Cell Line↗
PubMed1999

[Effects of pyrethroids on the glutamate uptake system in synaptic vesicle of rats].

In order to study the effects of cypermethrin and permethrin insecticides on the glutamate uptake of rat brain, brain synaptic vesicles and cypermethrin or permethrin were incubated with 3H-glutamate (37 KBq, 1 mumol/L). The radio activity was detected by a liquid scintillation counter. The results showed that cypermethrin and permethrin in the concentration of 10(-9)-10(-4) mol/L could inhibit the high affinity uptake of glutamate in the synaptosomes of cerebral cortex, hippocampus and striatum in a dose-response manner. Cypermethrin was more powerful than permethrin at the same dose. It was concluded that glutamate uptake inhibition might play a vital role in the neurotoxicity induced by pyrethroid insecticides.

Animals↗
PubMedDate not supplied

[Familial occurrence of granulocyte disorders in two children with recurrent otitis media].

UNLABELLED: Releasing of oxygen reactive species in activated granulocytes play an important role in the intracellular killing of bacteria. The respiratory burst is accompanied by chemiluminescence (chl). In vitro, granulocyte chl can be stimulated by nFLMP (bacterial peptide) or opsonised zymosan (OZ) after their binding to chemotactic surface receptors or FcR and CR, respectively. Chl can be induced also by non receptor way by PMA. We have found that blood granulocytes taken from children with recurrent upper respiratory tract infections demonstrated significantly decreased ability to oxidative metabolism after stimulation by n-FMLP. Inability of granulocytes to respond to only one of three above mentioned stimulators can suggests deficit of this enzyme isoform which is necessary for intracellular signal transduction. THE AIM of this study was to assess the activity of peripheral blood granulocytes in two children from two families, suffering from recurrent otitis media. MATERIALS AND METHODS: Study was performed in the 12 month old boy and 13 month old sick girl and in the children's parents. Chemiluminescence was measured in three blood samples, before and after n-FMLP, OZ and PMA stimulation. The light emission was measured in scintillation counter in presence of luminol. The study was performed after 2-3 weeks after treatment of otitis media. RESULTS: Both children had reduced response with FMLP and PMA and additionally, the girl had decreased response after OZ. Both boy's parents had decreased response only with n-FMLP. The diseased girl's father demonstrated a lack of response after all three stimulators. CONCLUSION: 1. The study of chemiluminescence stimulated with the three known stimulators increased the chance of recognising disturbances in granulocyte function. 2. Recognising wrong function child's granulocytes should be an indication for parents' study.

Adolescent↗
PubMed2000

[Study on the role of superoxide anion in promoting proliferation and transformation of rat liver oval cell line WB-E344].

OBJECTIVE: To study the role of superoxide anion (O2.-) in promoting proliferation and transformation of rat liver oval cell strain WB-F344. METHODS: WB-F344 cells cultured were stimulated directly by O2.- generated by interaction of xanthine with xanthine oxidase (X-XO). The effect of O2.- in promoting proliferation of WB cells was investigated by using MTT colorimetric analysis, 3H-Tdr incorporation liquid scintillation counter and 3H-Tdr incorporation autoradiography. WB cells initiated with N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) were promoted by stimulating continuously with O2.- of low concentration (X: 100 mumol/L, XO: 0.2 mU/ml). The transformation effect was tested by morphologic observation, karyotype analysis and anchorage-independent growth assay. RESULTS: Proliferation of WB cells was induced obviously by O2.- of low concentration for only one time. WB cells initiated with MNNG were transformed by action with O2.- of low concentration continuously for 15 d and typical morphologic character of transformed cells was observed. In karyotype analysis the cells chromosome number changed and the frequency of structure aberration raised dramatically. Also the transformed cells could form clone on self-solid culture medium. CONCLUSIONS: The biological effect of O2.- was related closely with its dose; The effects of low concentration in promoting proliferation and transformation of liver oval cells indicate its important role in hepatocarcinogenesis and antioxidation was able to provide a new clue in prevention and cure of hepatoma.

Animals↗
PubMed2003

[Glucose uptake of activated platelets and the influence by integrin antibodies].

OBJECTIVE: To study the signal transduction in the course of energy metabolism of platelets, and to provide a new theoretical basis for clinical application of the anti-activation of platelets by the monoantibody of integrin GPIIb/IIIa. METHODS: With or without the block of integrin GPIIb/IIIa monoantibody 10E5 and/or integrin alpha v beta 3 monoantibody 609, the uptake rate of tritium-labeled 2-deoxyglucose([3H]2-DG) by platelets activated by thrombin was counted in a liquid scintillation counter. The relationship between the energy metabolism of platelets and platelet integrin was investigated by the course of glucose uptake of individual vivo platelets. RESULTS: Compared with unactivated platelets, the glucose uptake of activated platelets increased, and it could be blocked by monoantibody 10E5 and partly blocked by 609. CONCLUSION: The glucose uptake of activated platelets can be suppressed by monoantibody 10E5, and the intergrin family is associated with the signal transduction of platelet energy metabolism. Integrin GPIIb/IIIa may play an important role in the procedure of platelet energy metabolism.

Blood Glucose↗
PubMed2001

[Role of hydrogen peroxide in promoting proliferation and transformation of rat liver oval cell line WB-F344].

OBJECTIVE: To study the role of hydrogen peroxide (H2O2) in promoting proliferation and transformation of rat liver oval cell line WB-F344. METHODS: Culturing WB-F344 cells were stimulated directly by H2O2. The effect of H2O2 in promoting proliferation of WB cells was investigated by using MTT colorimetric analysis and 3H-TdR incorporation liquid scintillation counter. The normal WB cells and the WB cells initiated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) were both promoted by stimulating continuously with H2O2 of low concentration (800 nmol/L). The transformation effect was tested by morphologic observation, karyotype analysis, and anchorage-independent growth assay. RESULTS: Proliferation of WB cells was induced obviously by H2O2 of low concentration for only one time. The normal WB cells and the WB cells initiated with MNNG were transformed by action with H2O2 of low concentration continuously for 28 days and typical morphologic characters of transformed cells were observed. In karyotype analysis the cells chromosome number changed and the frequency of structure aberration raised dramatically. Otherwise the transformed cells could form clone on self-solid culture medium. CONCLUSIONS: The biological effects of H2O2 were related to the low dose concentration in promoting proliferation and transformation of liver oval cells indicating its important role in hepatocarcinogenesis. Therefore antioxidants should be able to provide a new clue in prevention and cure of hepatoma.

Animals↗
PubMed2002

[Radioactivity for 137Cs, 125I, 131I, 59Fe, y 57Co windows from foods included in the basic alimentary basket and in the water, consumed in the state of Carabobo, Venezuela].

One of the input ways of radionucleids into the organism is through food intake. The aim of the present study is to measure the radioactivity levels in food and water samples within energy windows corresponding to 137Cs, 125I, 131I, 59Fe, and 57Co. Samples were taken from local and imported food belonging to the venezuelan basic alimentary basket and included: beef meat, hen egg, chicken bone, tomato, black bean, rice, powder milk from local dealers or imported from Italy and New Zeeland, potable water from the Valencia city aqueduct and bottled water from local sources or imported from Portugal. Radioactivity was measured with a well type Nal (TI) scintillation counter. Analyzed foods and water presented levels lower than the minimal detectable activity for 137Cs, 131I, 59Fe, 57Co, but it was detected in the Valencia city aqueduct water and in bottled water imported from Portugal, levels greater than the minimal detectable activity for the 125I energy window. These results strongly suggest the need of repeated multienergy windows monitoring of radioactivity of basic alimentary basket foods and potable water.

Animals↗
PubMedDate not supplied

Fish gonadotropin-releasing hormone gene and molecular approaches for control of sexual maturation: development of a transgenic fish model.

The prepro-GnRH gene and mRNA primary structure were fully established from Atlantic salmon (Salmo salar) and partially from rainbow trout (Oncorhynchus mykiss). Results show that the GnRH coding region of 30 base pairs is well conserved during evolution. In contrast, the GnRH-associated peptide (GAP) sequence shows very limited homology when the GnRH genes from mammalian and teleost species are compared. A simple method for selecting transgenic fish after transfer of the firefly luciferase gene was developed. The method involves bioluminescent measurement of live animals in a scintillation counter.

Amino Acid Sequence↗
PubMed1961

Estimation of total body fat from potassium-40 content.

On the assumption that the potassium content of the lean body mass is constant, it should be possible to estimate fat content in living man from a measurement of potassium-40 activity in the whole-body scintillation counter. A series of such measurements on children and young adults shows good correlations with skin-fold thickness and weight/height ratio as indices of fatness.

Adipose Tissue↗
PubMed1992

A two-site immunochemiluminometric assay for intact parathyroid hormone and its clinical utility in hemodialysis patients.

Measurement of serum parathyroid hormone (PTH) concentrations is complicated by the fact that there are several fragments of the hormone in the circulating as a result of the metabolism of PTH. The best way to study the secretory activity of the parathyroid glands directly may be to measure the biologically active intact PTH molecule. Recently, it has become possible to overcome these limitations by application of the two-site immunoradiometric assay (IRMA) to the measurement of intact PTH. The two-site immunometric technique has been applied to the two-site immunochemiluminescent assay (ICMA) for the measurement of circulating intact PTH. To evaluate the utility of measurements of serum intact PTH by two-site ICMA in hemodialysis patients, two-site ICMA and IRMA were compared in 104 hemodialysis patients. We found a good correlation (r = 0.93) between values obtained by ICMA and by IRMA. Although serum intact PTH by ICMA was significantly suppressed by rising plasma ionized calcium after a session of hemodialysis in 29 patients, mid-region PTH did not show a significant change. This result suggests the intact PTH assay is more suitable for the earlier detection of secondary hyperparathyroidism than the mid-region assay and may be useful for precise assessment of clinical status and response to therapeutic intervention designed to correct the progressive bone disease in hemodialysis patients. We conclude that two-site ICMA for serum intact PTH which could be measured without radioisotopes nor scintillation counter is as useful as IRMA in hemodialysis patients.

Humans↗
PubMed2003

[Investigation of the influence of Fas antigen on Hep G2 cells, an erythropoietin producing cell line].

We have already reported that serum levels of soluble Fas (sFas) and Fas-positive mononuclear cells increased concomitantly with deterioration in renal function and the increases were statistically significant. Moreover, the severity of renal anemia in renal failure patients was significantly correlated with serum levels of sFas. Therefore, we investigated whether or not Fas and Fas ligand (FasL) influenced the production of erythropoietin (EPO). Hep G2 cells, an EPO productive human hepatocellular carcinoma cell line, were cultured in MEM medium with 10% of FCS containing 1, 10 or 100 ng/ml of sFas, or sFasL. The EPO concentrations of the supernatants were measured by the ELISA method, Annexin V positive cells were calculated by flow cytometry, H3 leucin uptake was measured by a liquid scintillation counter, an MTT assay was performed using the light absorption method, fragmented nuclei were stained by the TUNEL method and DNA laddering was observed by agarose gel electrophoresis. Their characteristics evaluated at 0, 24, 48 and 72 hrs. Both EPO production and H3 leucin uptake were suppressed in culture with sFas or sFasL, dose-dependently and declines in MTT activities accompanied these changes at 24 hrs. In addition, nuclear fragmentation and DNA laddering were found to be stimulated in culture with sFas or sFasL at 48 hrs. These data suggest that sFas induced apoptosis and had a cytotoxic effect on Hep G2 cells. In conclusion, hyper-sFas-emia observed in chronic renal failure may regulate the production of EPO, which indicates that sFas acts as a uremic toxin.

Apoptosis↗
PubMed1992

[Binding affinity of ibuprofen in human tissues].

In vitro binding of ibuprofen (CAS 15687-27-1) to various human tissues was studied to explain differences in tissue concentration after local application of ibuprofen cream. Radioactive ibuprofen, was incubated with human skin, subcutaneous tissue, muscle, tendon, joint capsule for 2 h at 37 degrees C. Tissue specimens were washed and radioactivity was measured by a liquid scintillation counter. The results show specific binding of ibuprofen to the various tissues of different degrees. Despite of interindividual differences muscle tissues showed the highest, tendons the lowest concentrations of ibuprofen. These findings may explain the in vivo results, where higher concentrations of ibuprofen were found in muscle tissue compared with subcutaneous tissue.

Aged↗
PubMed1978

Pulmonary fibrinolytic activity: development of a sensitive radiochromatographic assay.

Pulmonary fibrinolytic activity was determined by a column assay which uses antibovine fibrinogen antibody covalently bound to cyanogen bromide-activated Sepharose 4B and 125I-labeled fibrinogen immunologically bound to the antibody. Fibrinogen-degrading enzyme (plasmin) was passed through the immobilized substrate; the released 1252I-labeled fragments were counted in a gamma-scintillation counter. A positive correlation was found between enzyme concentration and release of fibrinogen degradation products. The assay was sensitive, reproducible and particularly useful for measuring low enzyme activity in dilute bronchopulmonary lavage fluids.

Animals↗
PubMed2004

[Drug screening model acting on out-membrane protein OprM in pseudomonas aeruginosa efflux pump system].

OBJECTIVE: To establish an efflux pump inhibitor screening model with the out-membrane protein OprM in Pseudomonas aeruginosa efflux pump system as the target point. METHODS: Efflux pump out-membrane protein gene oprM was obtained from standard Pseudomonas aeruginosa PA01 strain. Expression of OprM protein was induced in E. coli strain HS151 with T-easy vector as the cloning vector, and pMMB67EH as the expression vector. In order to evaluate the function of OprM protein, we measured intracellular tetracycline concentrations with liquid scintillation counter, measured the diameters of bacteriostatic circles with paper disc, and then established a screening model accordingly. RESULTS: OprM protein was highly expressed. Using Pseudomonas aeruginosa as the main detecting bacteria, we established a drug screening model acting on OprM. A total of 1 600 microbial fermentation samples were screened with this model, among which 56 positive strains were found, with a positive rate of 3.5%. CONCLUSION: OprM plays an important role in drug efflux. The established model has good specificity and maneuverability.

Anti-Bacterial Agents↗