Alternative splicing of the human glucocorticoid receptor (hGR) primary transcript produces two receptor isoforms, termed hGRα and hGRβ. hGRα is a ligand-activated transcription factor which, in the hormone-bound state, modulates the expression of glucocorticoid-responsive genes by binding to specific glucocorticoid response element (GRE) DNA sequences. In contrast, hGRβ dose not bind glucocorticoids and is transcriptionally inactive. We demonstrate here that hGRβ inhibits the hormone-induced, hGRα-mediated stimulations of gene expression, including glucocorticoid-responsive reporter gene (cat) and endogenous p21 gene. We also demonstrate that hGRβ can inhibit hGRα-mediated regulation of proliferation and differentiation of a human osteosarcoma cell line (HOS-8603). Our studies on the expression of hGR mRNA in nephrotic syndrome patients indicate that the hGRα/hGRβ mRNA ratio in peripheral white blood cell of hormone-resistant patients is lower than that of hormone-sensitive patients and health volunteers. These results indicate that hGRβ may be a physiologically and pathophysiologically relevant endogenous inhibitor of hGRα

AIM: To clarify the effects of glucocorticoids on the messenger RNA expression of glucocorticoid receptor (GR? and GR?). METHODS: messenger RNA of GR ? and GR? were determined by quantitive RT-PCR. RESULTS: Besides GR? mRNA, GR? mRNA is also expressed in human osteosarcoma cell line HOS-8603, human ovarian carcinoma cell line 3AO and human peripheral white blood cells. After administration of dexamethasone, both GR? mRNA and GR? mRNA were down-regulated in a time-dependent and dose-dependent manner. CONCLUSION: GR? expresses in various kinds of human tissue cells. The expression of GR? is regulated by glucocorticoids.

AIM: To investigate the effect of PMA(phorbol 12-myristate 13-acetate) on the expression of CD18 and the mechanism. METHODS: The technique of quantitative RT-PCR analysis was used to measure the expression of CD18 mRNA in U937 cells treated by PMA. RESULTS: PMA could significantly induce CD18 mRNA expression in a dose and time-dependent manner. The induction effects of PMA on CD18 mRNA could be inhibited obviously by Myr (2 ?mol/L), a specific inhibitor of PKC, and APDC, an inhibitor of NF-?B, but not be inhibited by curcumin, a inhibitor of transcriptional factor AP-1. CONCLUSION: PMA enhanced the expression of CD18 via the pathway of PKC. Transcriptional factor NF-?B, but not AP-1, was essential for the gene transcription of CD18 in U937 cells treated by PMA.

AIM: To investigate the effect of glucocorticoid receptor beta(GR?) on the transcriptional activation function of glucocorticoid receptor alpha(GR?) and elucidate the biological significance of glucocorticoid receptor beta. METHODS: GR? (pRSH-GR?) and GR? responsive reporter gene cat (pMMTV-cat) were cotransfected into human osteosarcoma cell line (HOS-8603). Transient transfectants were treated with dexamethasone and the activity of cat was determined by the method of ELISA. The expression p21 messenger RNA was detected by the method of reverse transcription-polymerase chain reaction. RESULTS: GR? repressed the expression of reporter gene-cat in a dose-dependent manner. The expression of messenger RNA of p21, an endogenous target gene of GR?, was also inhibited by GR?. CONCLUSION: GR? can inhibit the transcriptional activation function of GR?. GR? may be an endogenous inhibitor of GR?.

AIM: To explore the possible role of p21 wafl gene in the effect of 1,25-dihydroxyvitamin D 3 on a human osteosarcoma cell line (HOS-8603) proliferation and differentiation. METHODS: The effect of 1,25(OH) 2D 3 on the expression of p21 wafl mRNA was determined by quantitative reverse transcription-polymerase chain reaction. The human osteosarcoma cell line stably expressing the p21 wafl mRNA, which named HOS-p21 wafl , was constructed by lipofectamine transfection, and the expression of p21 wafl protein was detected by Western blot. Then the growth curve of the HOS-p21 wafl cells and the expression of alkaline phosphatase (AKP) in the HOS-p21 wafl cells were investigated. RESULTS: The expression of endogenous p21 wafl mRNA in HOS-8603 cells was induced by 1,25(OH) 2D 3 in a time-dependent manner, reaching the maximum at 4 h, and remaining the inducible action for up to 24 h over basal levels. The HOS-p21 wafl cells grew much slower than the control cells, only reaching 50% of the control ones when cultured for up to 6 days. Histochemical analysis showed that the expression of alkaline phosphatase (AKP) in the HOS-p21 wafl cells increased remarkably.CONCLUSION: These results suggest that the p21 wafl mRNA expression induced by 1,25(OH) 2D 3 is one of important mechanisms responsible for the cellular effects of the hormone on HOS-8603 cells.

Objective: To observe the effects of perinatal exposure to benzo[a]pyrene (B[a]P) on the expression of pancreatic duodenal homeobox-1 (PDX-1) and mitochondrial transcription factor A (TFAM) and mitochondrial DNA copy number in offspring mice, and to explore the role of maternal exposure to B[a]P in the pancreatic function damage of offspring mice. Methods: Forty pregnant rats were randomly divided into the control group, the lowest dose group (2 μg/kg), the low dose group (200 μg/kg), medium dose group (800 μg/kg) and high dose group (1 600 μg/kg), with 8 rats in each group. From day 1 of pregnancy, each exposed group was given 0.2 mL/100 g body weight of B[a]P and corn oil mixture by gavage once a day until 3 weeks after delivery, while the control group was given the same dose of corn oil. The pancreatic tissue of three-week-old mice were collected after abdominal anesthesia for insulin immunohistochemical detection. The protein and mRNA expression levels of PDX-1 and TFAM, as well as mitochondrial DNA copy number were detected. Spearman rank correlation analysis was used to analyze the correlation between B[a]P exposure dose and the above indicators. Results: The insulin-positive area ratio and average optical density of insulin in the medium and the high dose groups were significantly lower than those in the control group (all P<0.05). The insulin-positive area ratio and average optical density of insulin were negatively correlated with the B[a]P dose (rs=-0.862 and -0.858, both P<0.05). The protein expression levels of PDX-1 and TFAM in the high dose group were significantly lower than those in the control group (both P<0.05). The protein expression levels of PDX-1 and TFAM were negatively correlated with the B[a]P dose (rs=-0.756 and -0.799, both P<0.05). The mRNA expression levels of PDX-1 and mitochondrial DNA copy number in the medium and high dose groups were significantly lower than those in the control group, and the mRNA expression level of TFAM in the high dose group was significantly lower than that in the control group (all P<0.05). The mRNA expression levels of PDX-1, TFAM, and mitochondrial DNA copy number were negatively correlated with the B[a]P dose (rs=-0.722, -0.550 and -0.840, all P<0.05). Conclusion Perinatal exposure to B[a]P can induce the damage of islet β cells in offspring rats, which may be related to the decreased expression of PDX-1 and TFAM and the copy number of mitochondrial DNA.

Objective: To investigate the benzo[a]pyrene ( B[a]P ) diolepoxide ( BPDE )-DNA adduct levels in offspring rats with intrauterine exposure to B[a]P, and examine the effects of BPDE-DNA adduct levels on pancreatic functional impairment and glucose metabolism in offspring rats. Methods: Forty pregnant rats were randomly divided into the blank control group, standard-dose group, low-dose group, medium-dose group and high-dose group (daily dose of 0, 2, 200, 800, 1 600 μg/kg B[a]P, respectively), of 8 animals in each group. Rats in the B[a]P treatment groups were administered by oral gavage with a mixture of B[a]P and corn oil at a dose of 0.2 mL/100 g body weight since day 1 of pregnancy until 21 days after delivery, while rats in the blank control group were given the same volume of coin oil by oral gavage. The BPDE-DNA adduct levels were measured and the pancreatic development was observed in the offspring rats 2 and 21 days and 12 weeks after birth, and the correlation between pancreas volume index and dose of exposure to B[a]P was examined using Spearman's rank correlation analysis. In addition, glucose metabolism was measured in offspring rats 12 months after birth using glucose tolerance test ( GTT ) and insulin tolerance test ( ITT ). Results: There was no abnormal appearance, death, abortion or preterm birth in pregnant or offspring rats in the five groups, and no significant differences were seen in activity, diet, drinking water or mental status in rats. The greatest level of BPDE-DNA adducts was measured in offspring rats 2 days after birth, with median levels ( interquartile range ) of 1 089.60 ( 586.10 ) to 1 405.49 ( 346.47 ) pg/mL, and no BPDE-DNA adducts were found in offspring rats 12 weeks after birth. The pancreas volume index correlated negatively with the dose of exposure to B[a]P in offspring rats 2 ( rs=-0.620, P=0.001 ) and 21 days after birth ( rs=-0.801, P=0.001 ). Hypoplasia of pancreas with loose tissues was seen in offspring rats 2 days after birth, while well pancreatic development was found in offspring rats 12 weeks after birth, with tight exocrine portion. GTT showed an increase in glucose levels in offspring rats in all five groups following abdominal injection of glucose and declined 30 min post-injection ( F=365.578, P<0.001 ), and ITT showed a tendency towards a decline in glucose levels in offspring rats in all five groups ( F=461.215, P<0.001 ). Conclusions The levels of BPDE-DNA adducts in offspring rats increase with the dose of intrauterine B[a]P exposure, and insulin resistance and impaired glucose tolerance occur 12 months post-exposure to B[a]P. Intrauterine B[a]P exposure affects pancreatic development in offspring rats and causes abnormal glucose metabolism in adult offspring rats.

AIM: To study the effect of dexamethasone(Dex) on the expression of CD18. METHODS: Quantitative RT-PCR analysis, Northern blotting technique were used to measure the expression of CD18 in U937 cells treated by PMA. RESULTS : Dex could significantly attenuated the effects of PMA in a dose-dependent manner (10 -6 mol/L-10 -10 mol/L). These effects of Dex (10 -7 mol/L) were completely aborted by RU-486 (10 -6 mol/L).CONCLUSION: Dex, via GR, could inhibit CD18 mRNA expression in U937 cells treated by PMA. The effects of Dex might be possibly depended on the counteracting action on the NF-?B.

Objective: To demonstrate the effects of symbiotic bacteria from lettuce on inactivation of norovirus（NV）. Methods: Symbiotic bacteria were isolated from the lettuces sampled from farmlands and supermarkets. NV mixed with symbiotic bacteria was set as the experimental group,without symbiotic bacteria as the control group. After the inactivation by high temperature,ultraviolet light（UV）and chlorine dioxide,the ratio of NV amount in the experimental group and the control group was calculated to evaluate the effects of symbiotic bacteria. The mechanism of symbiotic bacteria was revealed by detecting their effects on the protection of viral capsid protein from UV and on the adsorption of NV. Results: Eleven symbiotic bacteria were identified from lettuces,all of which were bacilli,mainly Pseudomonas. Ten symbiotic bacteria could improve the heat-resistant ability of NV,with Microbacterium oryzae,Cupriavidus taiwanensis（SC061204）,Pseudomonas furukawaii,Enterobacter tabaci and Pseudomonas resinovorans（SC061211）more significant. Eleven symbiotic bacteria could improve anti-UV ability of NV,with Pseudomonas putida,Microbacterium oryzae and Enterobacter tabaci more significant. Only one strain of Pseudomonas putida could improve anti-chlorine dioxide ability of NV（Class I hazard）. Pseudomonas putida,Microbacterium oryzae and Enterobacter tabaci could significantly reduce the damage of NV capsid protein. Nine symbiotic bacteria could promote NV adsorption into lettuces,with the promotion rates ranged from 1.04% to 46.73%;while Pseudomonas putida and Pseudomonas resinovorans（SC061211） could restrain NV absorption,with the promotion rates of -6.50% and -19.85%. Conclusion Symbiotic bacteria from lettuce may enhance the anti-inactivation of NV by protecting capsid protein and promoting adsorption of NV. It is recommended to control the presence of symbiotic bacteria in the process of inactivating NV.

Objective To explore the diagnostic value of exhaled volatile organic compounds (VOCs) for cystic fibrosis (CF). Methods A systematic search was conducted in PubMed, EMbase, Web of Science, Cochrane Library, CNKI, Wanfang, VIP, and SinoMed databases up to August 7, 2024. Studies that met the inclusion criteria were selected for data extraction and quality assessment. The quality of included studies was assessed by the Newcastle-Ottawa Scale (NOS), and the risk of bias and applicability of included prediction model studies were assessed by the prediction model risk of bias assessment tool (PROBAST). Results A total of 10 studies were included, among which 5 studies only identified specific exhaled VOCs in CF patients, and another 5 developed 7 CF risk prediction models based on the identification of VOCs in CF. The included studies reported a total of 75 exhaled VOCs, most of which belonged to the categories of acylcarnitines, aldehydes, acids, and esters. Most models (n=6, 85.7%) only included exhaled VOCs as predictive factors, and only one model included factors other than VOCs, including forced expiratory flow at 75% of forced vital capacity (FEF75) and modified Medical Research Council scale for the assessment of dyspnea (mMRC). The accuracy of the models ranged from 77% to 100%, and the area under the receiver operating characteristic curve ranged from 0.771 to 0.988. None of the included studies provided information on the calibration of the models. The results of the Prediction Model Risk of Bias Assessment Tool (PROBAST) showed that the overall bias risk of all predictive model studies was high, and the overall applicability was unclear. Conclusion The exhaled VOCs reported in the included studies showed significant heterogeneity, and more research is needed to explore specific compounds for CF. In addition, risk prediction models based on exhaled VOCs have certain value in the diagnosis of CF, but the overall bias risk is relatively high and needs further optimization from aspects such as model construction and validation.