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Kai Li

Publications and source records attributed to Kai Li.

64 records · Page 4Linked to original sources
PubMed2003

[Age-dependent alternations in beta-adrenoceptor function in human detrusor and possible mechanism].

OBJECTIVE: To study the age-dependent alternations in beta-adrenergic response and possible mechanism. METHODS: The response to beta-adrenergic agonists isoprenaline and BRL37344, forskolin and dibutyryl cyclic AMP (DBcAMP) of samples from senile people in 10 cases were examined by cellular functional test. Radioligand binding assay was also performed using non-selective beta-adrenergic receptors ligand [(3)H]-dihydroalprenolol ([(3)H]-DHA), the specimens of young men in 10 cases as the control group. RESULTS: There was no age-dependent change in the contractile response to potassium chloride. The relaxing responses to isoprenaline, BRL37344 and forskolin decreased by 15.0%, 17.6% and 12.6% respectively (P < 0.01). The pD(2) values of the isoprenaline and BRL37344 also declined significantly. There was no difference in the responses to DBcAMP between the two groups. The maximum binding site decreased significantly with increasing age, but the equilibrium-dissociation constant did not change. CONCLUSIONS: There is an age-related decline in beta-adrenergic responsiveness, which might be one of the causative factors of the reduced bladder compliance of the elderly. The decrease of cAMP level caused by the reduced receptor density and adenyl cyclase activity might be the molecular mechanisms underlying the changes of beta-adrenergic responsiveness.

Adult↗
PubMed2003

Age-dependent changes in beta-adrenoceptor function in human detrusors and possible mechanisms.

OBJECTIVE: To study age-dependent changes in beta-adrenergic responsiveness and their possible mechanisms. METHODS: Responsiveness to the beta-adrenergic agonists isoprenaline, BRL37344, forskolin, and dibutyryl cyclic AMP (DBcAMP) was examined in samples from 10 older patients by using a cellular function test. A radioligand binding assay was performed using the non-selective beta-adrenergic receptor ligand [3H]-dihydroalprenolol ([3H]-DHA). Specimens from 10 young men were used as controls. RESULTS: There were no age-dependent changes in contractile response to KCl. The relaxation responses to isoprenaline, BRL37344, and forskolin decreased in the aged group by 15.0%, 17.6%, and 12.6%, respectively (P < 0.001). The pD2 values for isoprenaline and BRL37344 also declined significantly. There was no difference in the responsiveness to dibutyryl cyclic AMP (DBcAMP) between the two groups; the maximum binding site decreased significantly with increasing age, but the equilibrium-dissociation constant did not change. CONCLUSIONS: There is an age-related decline in beta-adrenergic responsiveness which might be one of the causative factors of reduced bladder compliance in the elderly. A decrease in cAMP level caused by reduced receptor density and adenylyl cyclase activity might be the underlying molecular mechanism of the changes in beta-adrenergic responsiveness.

Adrenergic beta-Agonists↗
PubMed2003

[The effects of nandrolone phenylpropionate on androgen receptor of liver and sexual glands in burned rats].

OBJECTIVE: To assess the effects of nandrolone phenylpropionate (NP) on androgen receptor (AR) of liver and sexual glands in burned rats for supporting the clinical application of anabolic steroids. METHODS: Thirty-two Wistar rats with a deep second-degree cutaneous burn of 20% total body surface area were randomly divided into two groups to receive either 5 mg/kg NP (NP group) or normal saline as placebo (control group) every other day. The mean integrated optical density (mIOD) of androgen receptor (AR) in liver, testis, ovary tissues were measured by immunohistochemistry ENVISION and LSAB respectively on the 4th, 7th, 14th and 21st days after scalding. RESULTS: The density of AR in liver tissue in NP group was higher than that in control group (P < 0.05). The density of AR in testis and ovary tissues showed no significant difference between NP group and control group at every time-point (P > 0.05). The side-effect of NP at this dose level on sexual glands seemed limited. CONCLUSION: Nandrolone phenylpropionate up-regulated the density of AR in liver tissue, whereas it had no significant effects on the density of AR in testis and ovary tissues. NP was used with safety at this dose level in rats.

Animals↗
PubMed2003

[Effect of nandrolone phenylpropionate on expression of hepatic albumin-mRNA and androgen receptor in burned rats].

OBJECTIVE: To study the mechanism of nandrolone phenylpropionate (NP) on hepatic albumin mRNA and androgen receptor(AR) in burned rats. METHODS: Thirty-two Wistar rats with a deep second-degree cutaneous burn of 20% total body surface area were randomly divided into two groups: NP group (experimental group, 5 mg/kg NP) and normal saline as control group every other day. The expression copy quantity of albumin-mRNA and mean integrated absorbency(mIA) of AR in liver tissue were measured by quantitative fluorescent RT-PCR and immunohistochemistry respectively on the 4th, 7th, 14th and 21st days of post-burned. RESULTS: The expression levels of albumin-mRNA and AR in liver tissue in NP group were much higher than those in control group. The albumin-mRNA and AR expression increased significantly (P < 0.05) after 7 and 14 days, while the expression had no significant difference between NP group and control group on the 4th day. A positive correlation occurred between the expression level of albumin-mRNA and the quantity of AR in liver tissue(r = 0.936, P < 0.05). CONCLUSION: Nandrolone phenylpropionate up-regulated respectively the expression of albumin-mRNA and the density of AR in liver tissue.

Albumins↗
PubMed2002

Expression of intercellular adhesion molecule-1 in U937 foam cells and inhibitory effect of imperatorin.

AIM: To investigate the expression level of intercellular adhesion molecule-1 (ICAM-1) in a macrophage-derived foam cell model from human U937 cell line and the inhibitory effect of imperatorin (IMP) on the ICAM-1. METHODS: U937 cells were incubated with oxidized low density lipoprotein (ox-LDL) 80 mg/L for 48 h and a macrophage-derived foam cell model was established. The medium was pretreated with different concentrations of IMP (0, 25, 50, 100 micromol/L). ICAM-1 protein expression in cells was measured with Western blotting; ICAM-1 mRNA level in cells was measured by Northern blotting. RESULTS: After incubated with ox-LDL, ICAM-1 expression level increased greatly. The increase in ICAM-1 protein level and mRNA level was estimated to be about 15-fold and 10-fold. When the cells were pretreated with imperatorin (50, 100 micromol/L), the increase of ICAM-1 in foam cells were remarkably inhibited. Especially when pretreated with IMP 100 micromol/L, the ICAM-1 protein level decreased by 79 % and the mRNA level decreased by 74 % each compared to the level of foam cells. CONCLUSION: After incubated with ox-LDL in vitro, the U937 foam cells showed an enhanced ICAM-1 expression compared with normal U937 cells. IMP could inhibit the expression of ICAM-1 in U937 foam cells.

Angelica↗
PubMed2002

Modeling polychlorinated biphenyl congener patterns and dechlorination in dated sediments from the Ashtabula River, Ohio, USA.

Polychlorinated biphenyl (PCB) congeners were analyzed in four deep, dated sediment cores from the Ashtabula River (OH, USA), for the purpose of identifying relevant PCB sources and congener patterns. The time span for three of the cores is from the mid 1960s to 1998, whereas the fourth has a time span of six years. The total PCB concentrations are in the range of 0.4 to 6.8 microg/g dry weight, with the highest concentrations observed in samples from the 1970s. A factor analysis (FA) model with nonnegative constraints was used to investigate the sources and patterns of PCBs. Additionally, a new model, based on a least squares method, was developed to identify possible patterns of anaerobic dechlorination of PCBs in the sediments, and to quantify the relevant dechlorination pathways. Both models were validated successfully either by artificially created data sets (FA model) or by using laboratory data from the literature (dechlorination model). The FA model revealed two significant sources. The first was identified as a slightly altered Aroclor 1248. The second did not resemble any Aroclor closely, but was very similar to the overall average congener profile of all samples. Simulation of anaerobic dechlorination on an Aroclor 1248 profile from the literature, according to dechlorination activities H/H', as defined in the literature, yielded a congener profile very similar to that of the second pattern. This indicates the likelihood of anaerobic dechlorination of PCBs in Ashtabula River sediments.

Anaerobiosis↗
PubMed2002

Induction of apoptosis in mesothelioma cells by antisurvivin oligonucleotides.

Malignant pleural mesothelioma is a rare and aggressive tumor characterized by rapid progression, late metastases, and poor prognosis. In this study, we investigated the expression of survivin, a member of the inhibitors of apoptosis protein gene family, in mesothelioma and an antisense oligonucleotide-based gene therapy for mesothelioma using survivin as a target. Initially, we documented the expression of survivin in human mesothelioma cell lines and fresh tissues using reverse transcription-PCR and Western blot analysis. Our results showed that survivin was overexpressed in 7 of 8 (87.5%) mesothelioma cell lines assayed and in all (12 of 12; 100%) freshly resected mesothelioma tissues analyzed. To investigate the use of survivin as a therapeutic target on mesothelioma, we carried out transfections with antisurvivin oligonucleotides to induce apoptosis in mesothelioma cell lines MS-1 and H28. Results from cellular transfection and subsequent analysis using the flow cytometry demonstrated that antisurvivin oligonucleotides induced significantly greater apoptosis rates in the survivin-positive mesothelioma cell line H28 (42.5%) as compared with the control oligonucleotides (16.2%; P < 0.001). The survivin-negative cell line LRK1A (survivin-/-) did not apoptose with antisense oligonucleotides. Furthermore, time course evaluation by Western blot analysis showed that survivin was inhibited by antisurvivin oligonucleotides within 12 h after transfection. Our results show, for the first time, that survivin, an inhibitors of apoptosis protein family gene member, is highly overexpressed in malignant pleural mesothelioma. Down-regulation of survivin by a targeted antisense oligonucleotide appears to be an effective gene therapy approach to the treatment of mesothelioma.

Annexin A5↗
PubMedDate not supplied

Modulation of phosphoenolpyruvate synthase expression increases shikimate pathway product yields in E. coli.

Product yields in microbial synthesis are ultimately limited by the mechanism utilized for glucose transport. Altered expression of phosphoenolpyruvate synthase was examined as a method for circumventing these limits. Escherichia coli KL3/pJY1.216A was cultured under fed-batch fermentor conditions where glucose was the only source of carbon for the formation of microbial biomass and the synthesis of product 3-dehydroshikimic acid. Shikimate pathway byproducts 3-deoxy-D-arabino-heptulosonic acid, 3-dehydroquinic acid, and gallic acid were also generated. An optimal expression level of phosphoenolpyruvate synthase was identified, which did not correspond to the highest expression levels of this enzyme, where the total yield of 3-dehydroshikimic acid and shikimate pathway byproducts synthesized from glucose was 51% (mol/mol). For comparison, the theoretical maximum yield is 43% (mol/mol) for synthesis of 3-dehydroshikimic acid and shikimate pathway byproducts from glucose in lieu of amplified expression of phosphoenolpyruvate synthase.

Escherichia coli↗
PubMedDate not supplied

Altered glucose transport and shikimate pathway product yields in E. coli.

Different glucose transport systems are examined for their impact on phosphoenolpyruvate availability as reflected by the yields of 3-dehydroshikimic acid and byproducts 3-deoxy-d-arabino-heptulosonic acid, 3-dehydroquinic acid, and gallic acid synthesized by Escherichia coli from glucose. 3-Dehydroshikimic acid is an advanced shikimate pathway intermediate in the syntheses of a spectrum of commodity, pseudocommodity, and fine chemicals. All constructs carried plasmid aroF(FBR) and tktA inserts encoding, respectively, a feedback-insensitive isozyme of 3-deoxy-d-arabino-heptulosonic acid 7-phosphate synthase and transketolase. Reliance on the native E. coli phosphoenolpyruvate:carbohydrate phosphotransferase system for glucose transport led in 48 h to the synthesis of 3-dehydroshikimic acid (49 g/L) and shikimate pathway byproducts in a total yield of 33% (mol/mol). Use of heterologously expressed Zymomonas mobilis glf-encoded glucose facilitator and glk-encoded glucokinase resulted in the synthesis in 48 h of 3-dehydroshikimic acid (60 g/L) and shikimate pathway byproducts in a total yield of 41% (mol/mol). Recruitment of native E. coli galP-encoded galactose permease for glucose transport required 60 h to synthesize 3-dehydroshikimic acid (60 g/L) and shikimate pathway byproducts in a total yield of 43% (mol/mol). Direct comparison of the impact of altered glucose transport on the yields of shikimate pathway products synthesized by E. coli has been previously hampered by different experimental designs and culturing conditions. In this study, the same product and byproduct mixture synthesized by E. coli constructs derived from the same progenitor strain is used to compare strategies for increasing phosphoenolpyruvate availability. Constructs are cultured under the same set of fermentor-controlled conditions.

3-Deoxy-7-Phosphoheptulonate Synthase↗