Cytokinins. Extraction, separation, and analysis.
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Chromatography↗
Biomedical subjects
H Zhang
Publications and source records attributed to H Zhang.
Chronic toxicity of rare-earth elements on human beings: implications of blood biochemical indices in REE-high regions, South Jiangxi.
Blood analyses for rare-earth element (REE)-high background regions in South Jiangxi show that the population averages of many of the biochemical indices deviate markedly from normal values in the normal region. These deviations are thought to be caused by prolonged intake of REE through food chains in view of that the toxicity of other harmful metals such as Pb and Cd can be neglected because of their insignificant amounts in the environment. In comparison with the normal region, blood biochemical indices abnormal in the REE-high regions are manifested as low total serum protein (TSP), albumin, beta-globulin, glutamic pyruvic transitanase, serium triglycerides, and immunoglobulin, but high cholesterol. These deviations may be related to the REE concentration and composition of food chains, and are sex dependent. Certain blood indices (such as TSP) of different age groups in the LREE-high region indicate that the influence of REE on males is a one-way irreversible process, whereas females show a strong ability of restoration.
Adult↗
Rare-earth element distribution characteristics of biological chains in rare-earth element-high background regions and their implications.
The rare-earth element (REE) contents of water and vegetables from two typical REE-high background regions and a normal region in Gannan, Jiangxi Province, indicated that the REE contents were significantly different from those of water and vegetables, respectively. The average values are 0.03 mg/L and 0.11 mg/L REE for water from regions A and B. As the REE contents of vegetables from region A are different from region B, it is suggested that there are a number of factors controlling the REE distribution from those among plants. By comparing with the normal region, the soluble REE contents of water from the REE-high background regions are higher than those of the normal region by factors of 18 and 68, respectively. The REE contents of most plants and crops from regions A and B are higher than those of the normal region. It is clear that the REEs are the indispensable elements of plants during their growing period. Why are the REE contents of some plants from regions A and B usually higher than those from the normal region? The answer is that the plants and crops have passively absorbed REE during their growth.
China↗
Bacteriostatic effects of cerium-humic acid complex: an experimental study.
The bacteriostatic potency of the cerium-humic acid complex was evaluated by experimental measurement of this complex interaction with E. coli, Bacillus pyocyaneus, Staphylococcus aureus, Leuconostoc and Streptococcus faecalis, and by comparison bacteriostatic effects with the cerium-citrate complex. The experimental results indicated that the cerium-humic acid complex strongly inhibited growth of all five bacterial strains, and its diameter of bacteriostatic circles were more than 30 mm. The minimal bacteria-inhibiting concentration were 1 x 10(-3), 2 x 10(-3) and 1 x 10(-2) mol/L for E. coli and Bacillus pyocyaneus, Staphylococcus aureus, and Leuconostoc and Streptococcus faecalis individually, and the measured minimal bactericidal concentrations were 2 x 10(-3) and 1 x 10(-2) mol/L for Bacillus pyocyaneus, E. coli, and Leuconostoc. To kill Staphylococcus aureus and Streptococcus faecalis, the concentration had to be more than 1 x 10(-20 mol/L. On the contrary, we found that cerium-citrate complex did not inhibit the growth of the above five bacteria, but stimulated bacterial growth. The completely different bacteriostatic results of two cerium complexes may hint that the association and chemical properties of the two complexes were different.
Anti-Bacterial Agents↗
Phosphorylation of 13 kDa nuclear protein in hepatocarcinomas induced by peroxisome proliferators.
Peroxisome proliferators (PPs) are nongenotoxic compounds causing the emergence of hepatocellular carcinoma in rodents, but the mechanisms of the hepatocarcinogenesis have been unclear. The authors examined the changes in phosphorylation of nuclear proteins after treatment with (4-chloro-6-[2,3-xylidino]-2-pyrimidinylthio) acetic acid (Wy-14,643). Wy-14,643 (0.1% w/w in diet) was given orally to male F-344 rats for up to 80 wk. In the hepatocarcinomas induced by Wy-14,643, phosphorylation of 13 kDa nuclear protein (NP 13), which was resistant to alkaline treatment, was significantly increased. NP 13 phosphorylation gradually increased, dependent on treatment period. Furthermore, in the hepatocarcinomas induced by other PP, di(2-ethylhexyl)phthalate, increase in NP13-phosphorylation was also observed. Therefore, NP 13-phosphorylation may relate to development of preneoplastic or neoplastic lesions induced by PPs.
Animals↗
Effect of the grapefruit flavonoid naringin on pharmacokinetics of quinine in rats.
The effect of the grapefruit flavonoid naringin, an inhibitor of CYP3A4, on the pharmacokinetics of quinine in rats after oral or intravenous (i.v.) dosing of quinine was investigated. Female Wistar rats (wt 190-220 g) were used in two separate studies, i.e. oral and i.v. administration of quinine. The animals were divided into two groups, one served as control and the other group was pretreated with 25 mg/kg naringin once a day for 7 consecutive days before the pharmacokinetic study. On the study day, quinine (25 mg/kg) was administered to the rats by either the oral or i.v. route. Blood samples were collected at different times, up to 6 h after quinine administration. Plasma quinine concentration was assayed by HPLC. Pretreatment with naringin did not cause any significant change in the pharmacokinetics of quinine after the i.v. dose. However pretreatment with naringin led to a 208% increase in peak plasma concentration (Cmax), a 93% increase in time to reach Cmax (tmax), and a 152% increase in the area under the plasma concentration-time curve (AUC) of quinine after oral administration. Consequently, the oral bioavailability of quinine was significantly increased (p < 0.05) from 17% (control) to 42% after pretreatment with naringin. There was no significant difference in the elimination half-life (t(1/2)beta) of quinine between the two groups. These results suggest that pretreatment with the grapefruit flavonoid naringin is associated with increased oral bioavailability of quinine in rats.
Administration, Oral↗
Radiation-induced DNA damage in tumors and normal tissues. VI. Estimation of the hypoxic fraction of experimental tumors.
For several years, we have concentrated our efforts on validating the use of radiation-induced DNA strand breaks and DNA-protein crosslinks to assess the oxygenation status of tumors and normal tissues. We have demonstrated that (1) the oxygen dependence of strand break formation is identical to that of radiation-induced cell killing; (2) the oxygen dependence of DNA-protein crosslink formation is the mirror image of that of radiation-induced cell killing; and (3) the formation of these radiation-induced DNA lesions is predominantly dependent on the oxygen concentration near the DNA and is independent of the cell type, metabolic status, proliferative status, pH of the surrounding environment, and composition or properties of the proteins tightly associated with the DNA. In the present study, the hypoxic fraction of three experimental tumors was estimated using our assay of radiation-induced DNA damage. The average hypoxic fraction of a large number of tumors estimated with this assay of radiation-induced DNA damage for (1) WiDR human colorectal carcinoma xenografts (40.8 +/- 4.2%), (2) 66 mouse mammary adenocarcinoma tumors (41.8 +/- 3.1%), and (3) subcutaneous tumors grown from 9L rat brain tumor cells (95% CI =-8.2-4.2%) was not statistically different from that of a large number of tumors measured for each of these tumor models by the paired survival curve method (38.3 +/- 6. 3%, 28.9 +/- 5.5%, 95% CI = 2.2-4.4%, respectively). When the hypoxic fraction measured by the alkaline elution method on one half of an individual tumor was compared to that measured by the paired survival curve method on the other half of the same tumor, no statistical correlation was found for either 66 or WiDR tumors. Although this assay of radiation-induced DNA damage can be used effectively in the laboratory to answer a number of important questions about the oxygenation status of animal tumors and normal tissues, failure to reliably estimate the hypoxic fraction of individual tumors and technical considerations make it unlikely that the assay can be used in the clinic to estimate the hypoxic fraction of human tumors.
Adenocarcinoma↗
Transplantation of normal and genetically modified adrenocortical cells.
Cell transplantation techniques have been applied to the study of the biology of the adrenal cortex and to adrenocortical cell proliferation, differentiation, and senescence. Primary bovine adrenocortical cells, primary human adrenocortical cells and genetically modified bovine adrenocortical cells have been transplanted. Successful methods include transplantation of cells beneath the kidney capsule and several subcutaneous cell transplantation procedures. In successful transplants the cells form a functional vascularized tissue structure that allows the host animals to survive adrenalectomy. We show here that subcutaneous cell transplantation does not depend on embedding cells in collagen gel before introduction into the host animal. Subcutaneous transplants secrete both cortisol and aldosterone. However, the variability of plasma aldosterone levels indicates that the factors that determine glomerulosa-type and fasciculata-type cell function in transplant tissues are not well understood.
3T3 Cells↗
Gamma-radiation-induced single cell DNA damage as a measure of susceptibility to lung cancer: a preliminary report.
The comet assay is a sensitive and rapid method for detecting DNA single-strand and double-strand breaks and the individual cell's DNA repair profile. This pilot study was designed to determine whether the comet assay could measure inherited susceptibility to lung cancer. We applied the comet assay in the alkaline condition to test the DNA damage in gamma-irradiated and untreated cultured peripheral blood lymphocytes of 31 cases with previously untreated lung cancer and 39 controls. For each culture, 200 consecutive cells were examined and the number of cells with DNA uncoiling under electrophoresis ( ) was recorded. The comet tail length (the radius of the nucleus plus the length of the migrated DNA) at 400-fold magnification was measured for the first 50 identified comet cells. The mean number of induced comet cells was significantly higher in cases (96.0+/-45.7) than matched controls (68.9+/-35.8) (P<0.05). However, no significant difference was observed in induced comet tail length between cases and controls. When we categorized the number of comet cells by the 75th percentile value in the controls, a higher number of comet cells was associated with significantly increased risk for lung cancer [odds ratio = 4.8 (confidence intervals of 1.5, 15.2)] after adjustment for age, sex, ethnicity and smoking status. The number of gamma-irradiation-induced comet cells (r=0.499, P<0.05) and comet tail length (r=0.520, P<0.05) correlated with the results on a previously reported lung cancer susceptibility marker, bleomycin sensitivity. Also, the number of gamma-irradiation-induced comet cells correlated with the results of the benzo[alpha]pyrene diol epoxide mutagen sensitivity assay, which quantifies induced chromatid breaks (r=0.275, P<0.05). The comet assay might be a simple and inexpensive tool for detecting genetic susceptibility to lung cancer.
Adult↗
Dexamethasone differentially regulates expression of carboxylesterase genes in humans and rats.
Carboxylesterases play important roles in the metabolism of endogenous and foreign compounds, therefore, xenobiotic regulation of carboxylesterase gene expression has both physiological and pharmacological significance. We previously reported that liver microsomal esterase activity was significantly decreased in rats treated with dexamethasone accompanied by a decrease in immunoreactive proteins of rat hydrolase A, B, and C. The aim of this study was to determine whether the suppressed expression of these enzymes was linked to the change of the mRNA levels, and whether cultured hepatocytes responded similar to whole animals to this chemical. Northern blotting analyses demonstrated that the levels of the corresponding mRNA were markedly decreased in rats treated with dexamethasone, suggesting that the suppressed expression is achieved through trans-suppression and/or increased degradation of the transcripts. Exposure of cultured rat hepatocytes to nanomolar levels of dexamethasone markedly decreased the levels of immunoreactive proteins of hydrolase A, B, and C. In contrast, exposure of cultured human hepatocytes to dexamethasone caused a slight increase in HCE-1 and HCE-2, two major forms of human liver microsomal carboxylesterases. The inductive effects in human hepatocytes were observed only when micromolar concentrations of dexamethasone were used. These results suggest that a major species difference exists regarding the regulation of carboxylesterase gene expression by dexamethasone. Both the glucocorticoid receptor and the pregnane X receptor are known to mediate dexamethasone action. Differential concentrations required suggest that suppression of rat hydrolases is mediated by the glucocorticoid receptor, whereas the induction of human carboxylesterases is mediated by the pregnane X receptor.
Amino Acid Sequence↗
[Amplification and sequence of human CD14 gene from human mononuclear cell in peripheral blood].
OBJECTIVE: To introduce a new method for getting human CD14 gene. METHODS: Based on the character of CD14 gene, the authors amplified the CD14 gene directly from genome DNA of human mononuclear cell in peripheral blood by PCR for the first time. RESULTS: A human CD14 gene about 1.1 kb was successfully amplified from genome DNA of human mononuclear cell in peripheral blood, and the sequence analysis has indicated that the CD14 gene cloned in this way is the same as the sequence reported by other authors. CONCLUSION: It is a simple and effective method to obtain human CD14 gene from genome DNA of human mononuclear cell in peripheral blood.
Base Sequence↗
Linkage of the genes controlling natural killer cell activity to HLA-B.
OBJECTIVE: To study whether there is a relationship between HLA-B alleles and low natural killer(NK) cell activity in Chinese. METHODS: The subjects were 34 unrelated healthy individuals (10 males and 24 females), aged 25-60 years, and 31 individuals (17 males and 14 females) from 11 families, aged 22-70 years, previously genotyped for HLA class I, II, complotypes and haplotypes that were assigned based on family studies. The unrelated individuals were typed for HLA-A, -B antigen by a microcytotoxicity assay and all the subjects were tested for NK cell activity by lactate dehydrogenase (LDH) enzyme-release assay. RESULTS: Statistical analysis showed that 30 lysis unit(LU) was the cutoff value of low and high NK reactors. The frequency of low reactor individuals homozygous for HLA-B was significantly higher than that for those for HLA-DR(P< 0. 05). The associated genes included HLA-B13, B40, B46, B7, B57, defined as NKB1 genes, and HLA-B44 as NKB2 gene. Family studies provide further evidence that the genes controlling low NK cell activity were located in the MHC region and it was a recessive trait. CONCLUSION: There were recessive genes associated with HLA-B controlling low NK cell activity in Chinese. The NKB alleles were partly different from those found in Caucasian.
Adult↗
[Examination and evaluation of sIL-6R, sgp130 in serum in patients with chronic hepatopathy].
OBJECTIVE: To observe the variation of soluble interleukin-6 receptor (sIL-6R) and soluble interleukin-6 receptor beta strands (sgp130) in patients with chronic hepatopath. METHODS: We examined sIL-6R and sgp130 level in 40 patients with chronic hepatitis (CH), 15 with cirrhosis following hepatitis, and 35 normal controls (NC) in serum by enzyme linked immunosorbent assay (ELISA) method. RESULTS: The content of sIL-6R and sgp130 in serum was higher in CH group (224.27 mug/L and 489.35 mug/L, respectively) than NC group (174.81 mug/L and 273.64 mug/L respectively). The two parameters above in patients with hepatocirrhosis were higher than those in patients with chronic hepatitis, and the content in order of quantity was severe>moderate>slight. There was significant difference among the three groups (P<0.05, P<0.01), and positive correlation between sIL-6R and sgp130 level (r=0.481, P<0.05), between sIL-6R, sgp130 level and total bilirubin level (r=0.417, r=0. 428, P<0.01). While sIL-6R, sgp130 was no significant correlation to ALT (r=0.173, r=0.182, P>0.05). CONCLUSION: sIL-6R and sgp130 in serum are associated with the development of chronic hepatopath, and therefore can guide the assessment of prognosis.
Adult↗
The value of serum GPDA-F for the diagnosis of primary hepatocellular carcinoma.
OBJECTIVE: To investigate the role of glycylproline dipeptidyl aminopeptidase isoenzymes in the diagnosis of primary hepatocellular carcinoma (PHC). METHODS: We developed a stage gradient polyacrylamide gel electrophoresis system to separate serum GPDA isoenzymes. Total GPDA activities, alpha-fetoprotein, the sizes of tumors and alanine aminotransferase (ALT) activities were also measured simultaneously and the correlation between GPDA-F and these indices was analyzed. RESULTS: Serum GPDA was separated into two bands, namely fast band (GPDA-F) and slow band (GPDA-S). GPDA-F was negative in all healthy persons as well as in the patients with benign liver filling defects, while it was positive in 85.3% cases of PHC. Liver cirrhosis, chronic hepatitis, extrahepatic carcinoma and metastatic liver carcinoma had low positive rates. GPDA-F was positively correlated with serum total GPDA activities, but had no correlation with AFP and size of the tumors. There was the correlation between GPDA-F and ALT in benign liver diseases, but no correlation between GPDA-F and ALT in PHC. Serial measurements of serum GPDA-F showed that GPDA-F was persistently positive in PHC but might change into negative in benign liver diseases. Dynamic determination of GPDA-F might be helpful to differentiate true positive of PHC from false positive of benign liver diseases. CONCLUSION: GPDA-F is a new serum marker of PHC. Measurement of serum GPDA-F is of value for the diagnosis of PHC, especially for those at early stage or with negative AFP.
Alanine Transaminase↗
Gene variation of 5'-NCR and core region in serum samples collected from patients with HCV infection.
OBJECTIVE: To study the variation of HCV 5'-NCR and core gene in serial sera collected from patients with HCV infection. METHODS: Serial sera were collected from 4 plasma-donors with HCV infection. 5'-NCR and core gene were amplified, sequenced and analyzed using software. RESULTS: All the sequences obtained from the serial sera of patients with HCV infection were 1b and 2a subtypes. The variation of 5'-NCR only related to the genotype, and not associated with patients and time of serum collection. However, the sequences of core gene were not identical in HCV strains isolated from different patients. The sequences of those two regions of the same genotype isolated from the same patient did not change with time. CONCLUSION: 5'-NCR is more conserved than the core region and the genotype is the major cause of gene variation. No change in sequences of those two regions is found at the different points of time.
5' Untranslated Regions↗
Mutagenicity of methyl tertiary butyl ether.
Methyl tertiary butyl ether (MTBE), the main component of oxygenated gasoline, is added to gasoline as an octane enhancer to reduce automotive emissions. We evaluated the mutagenicity of domestic MTBE using the Ames test, unscheduled DNA synthesis (UDS) assay, and NIH/3T3 cell micronucleus test. MTBE did not show any mutagenic potential in the Ames assay (TA98, TA100 strains) with or without rat liver-derived metabolic activation system (S-9). In rat primary hepatocyte UDS assay, a dose-response relationship was observed, which meant that MTBE might damage normal DNA and induce unscheduled DNA synthesis. MTBE did not show positive results in the NIH/3T3 cell micronucleus test. It could be concluded that MTBE has some degree of mutagenicity.
3T3 Cells↗
Expression of metallothionein in invasive ductal breast cancer in relation to prognosis.
The aim of this study was to assess the presence and clinical significance of metallothionein (MT) in primary invasive ductal carcinoma of the breast. We investigated 96 cases of routinely fixed and paraffin-embedded primary breast carcinomas with the immunohistochemical method. Positive staining for MT was observed in 52.1% of specimen. In most cases both nuclear and cytoplasmic staining was seen. A statistically significant association was found between MT-positive staining and nuclear grade (p < 0.01). MT-positive cases had a significantly poorer prognosis when compared with the MT-negative cases (p < 0.01). We concluded that the MT expression may be of a prognostic value for primary invasive ductal carcinoma of the breast and is possibly an indicator of more aggressive and less differentiated carcinoma cells.
Adult↗
Adhesion of transplanted chondrocytes onto cartilage in vitro and in vivo.
OBJECTIVE: The specific objectives of this study using organ culture were (1) to transplant chondrocytes onto an intact cartilage surface; (2) to genetically modify endogenous and transplanted chondrocytes; and (3) to assess the ability of these cells to continually express a gene product. The specific objective with in vivo experiments was to transplant chondrocytes with intraarticular injections to cartilage. METHODS: Fluorescent membrane and intracellular dyes were used in conjunction with confocal microscopy to observe the integration of transplanted chondrocytes into cartilage both in vitro and in vivo. The distribution and duration of binding of rat, canine, and bovine chondrocytes to cartilage explants and the duration of expression of genes transduced into the transplanted chondrocytes were also determined. We used the vector AdlacZ, an E1 and E3 deleted replication defective adenoviral vector that contains the beta-galactosidase gene driven by the beta-actin promoter and the cytomegalovirus enhancer. RESULTS: The transplanted chondrocytes had a patchy distribution after in vitro or in vivo transplantation and buried themselves within the cartilage over time. Chondrocytes infected with the adenoviral vector AdlacZ soon or well after transplant to cartilage explants were maintained on the cartilage and continued throughout the duration of each trial to produce beta-galactosidase coded by the adenoviral vector. The cartilage plugs were infected with AdlacZ at 2 days or one, 2, 5, or 8 weeks after the chondrocytes were transplanted. The cartilage slices were then cultured from 15 days for chondrocytes infected at 8 weeks to 60 days for chondrocytes infected at 2 days post-transplant before determining the expression of beta-galactosidase. CONCLUSION: These results support the possibility of repairing cartilage by intraarticular injections of chondrocytes. Transduction of chondrocytes with genes producing a variety of matrix promoting proteins should further enhance the reconstruction of osteoarthritic cartilage.
Animals↗