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Biomedical subjects

J Chen

Publications and source records attributed to J Chen.

At least 217 records · Page 12Linked to original sources
PubMed2003

A novel polygalacturonic acid bioflocculant REA-11 produced by Corynebacterium glutamicum: a proposed biosynthetic pathway and experimental confirmation.

Corynebacterium glutamicum CCTCC M201005 produces a novel polygalacturonic acid bioflocculant, REA-11, consisting of galacturonic acid as the main structural unit. A biosynthetic pathway of REA-11 in C. glutamicum CCTCC M201005 was proposed. Evidence for the biosynthetic pathway was provided by: (1) analyzing the response upon addition of UDP-glucose to the culture medium; (2) detecting the presence of several key intermediates in the pathway; and (3) correlating the activities of several key enzymes involved in the pathway with the yields of polygalacturonic acid. The production of polygalacturonic acid was improved by 24%, while the activities of UDP-galactose epimerase and UDP-galactose dehydrogenase were improved by 200% and 50%, respectively, upon addition of 100 microM UDP-glucose. In addition, the key intermediates in the proposed biosynthetic pathway, such as UDP-glucose, UDP-galactose, and UDP-glucuronic acid, were detected in cell-free extracts. Furthermore, the activities of UDP-glucose pyrophosphorylase (R2=0.97), UDP-galactose epimerase (R2=0.75) and UDP-galactose dehydrogenase (R2=0.89) were well correlated with the yields of polygalacturonic acid when different sugars were used as sole carbon sources. Therefore, the biosynthetic pathway of REA-11 in C. glutamicum CCTCC M201005 starts from phosphate-1-glucose, which was then converted to UDP-glucose by UDP-pyrophosphorylase. Predominantly, the UDP-glucose was converted to UDP-galactose by UDP-galactose epimerase; the latter was further converted to UDP-galacturonic acid by UDP-galactose dehydrogenase, which was presumably polymerized to polygalacturonic acid bioflocculant REA-11 by an unknown glucosyltransferase and a polymerase.

Corynebacterium↗
PubMed2003

Health-related quality-of-life outcomes of sirolimus-treated kidney transplant patients after elimination of cyclosporine A: results of a 2-year randomized clinical trial.

BACKGROUND: This study compared 2-year health-related quality-of-life (HRQL) outcomes of sirolimus (SRL)-treated kidney transplant patients after elimination of cyclosporine A (CsA) to patients continuing on a combined CsA and SRL regimen. METHODS: A randomized, open-label, clinical trial was performed in Europe, Australia, and Canada. Four hundred thirty kidney transplant patients were randomly assigned to sirolimus plus steroids (ST) (n=215) or SRL and CsA+ST (n=215) therapy after 3 months of combined SRL+CsA+ST treatment. HRQL was measured using the Kidney Transplant Questionnaire (KTQ) and the SF-36 Health Survey at month 3 (time of randomization) and months 12 and 24 after transplantation. Repeated-measures analysis of covariance was used to evaluate treatment differences in HRQL scores over the 2-year period. RESULTS: HRQL scores were available for 361 (86%) eligible study patients. Statistically significant treatment-by-assessment time interactions, favoring SRL+ST, were found on KTQ Fatigue (P=0.0158) and Appearance scores (P=0.0007). No treatment differences were observed in KTQ Physical Symptom, Uncertainty-Fear, and Emotion scores. Statistically significant treatment-by-assessment time interactions were observed for SF-36 Vitality scores (P=0.0203) but not other SF-36 scores (P>0.05). For Vitality scores, the SRL+ST group remained stable (mean, 0.4-point change) from month 3 to month 24 compared with decreases in the SRL+CsA+ST group (mean, -6.5-point change). CONCLUSIONS: SRL-based therapy with early elimination of CsA results in fewer appearance-related problems, less fatigue, and better vitality compared with continuous treatment with SRL, CsA, and ST.

Adult↗
PubMed2003

Reproduction and cytogenetic characterization of interspecific hybrids derived from Cucumis hystrix Chakr. x Cucumis sativus L.

Interspecific hybrids between Cucumis hystrix Chakr. (2n = 2 x = 24) and Cucumis sativus L. (2n = 2 x = 14) were produced by means of F(1) (2n = 19) embryo rescue and subsequent chromosome doubling. The hybridity was confirmed by genomic in situ hybridization (GISH) and chromosome analysis. The amphidiploid (2n = 38) was self-pollinated and backcrossed to cucumber resulting in lines with improved crossability to C. sativus. Examination of shape, stainability, and germination rate of pollen grains and yield as a function of mature fruit set per ten pollinated flowers indicated a tendency for increased fertility in BC(1)S(1) progeny when compared to F(1) and amphidiploid offspring. Cytogenetic characterization of F(1) and amphidiploid progeny was performed. Generally normal meioses produced viable pollen grains, and fertilization resulted in partial fertility restoration in amphidiploid progeny. Chromosome anomalies such as "frying-pan trivalent", chromosome lagging and spindle mis-orientation were also observed. In most of the PMCs of the F(1) diploid hybrid progeny, 19 univalents were observed at diakinesis and MI. In the amphidiploid, more than 90% of the configurations at MI consisted of the predicted 19 bivalents and less than 5% contained multivalents [trivalents (2.3%) + quadrivalents (0.3%)], suggesting the presence of preferential pairing, and a distinctive parental genome as well. The chiasmata observed between homoeologous chromosomes further demonstrated the introgression of the C. hystrix genome into that of C. sativus.

Chimera↗
PubMed2003

Pharmacological characterization of a novel antiglaucoma agent, Bimatoprost (AGN 192024).

Replacement of the carboxylic acid group of prostaglandin (PG) F(2alpha) with a nonacidic moiety, such as hydroxyl, methoxy, or amido, results in compounds with unique pharmacology. Bimatoprost (AGN 192024) is also a pharmacologically novel PGF(2alpha) analog, where the carboxylic acid is replaced by a neutral ethylamide substituent. Bimatoprost potently contracted the feline lung parenchymal preparation (EC(50) value of 35-55 nM) but exhibited no meaningful activity in a variety of PG-sensitive tissue and cell preparations. Its activity seemed unrelated to FP receptor stimulation according to the following evidence. 1) Bimatoprost exhibited no meaningful activity in tissues and cells containing functional FP receptors. 2) Bimatoprost activity in the cat lung parenchyma is not species-specific because its potent activity in this preparation could not be reproduced in cells stably expressing the feline FP receptor. 3) Radioligand binding studies using feline and human recombinant FP receptors exhibited minimal competition versus [(3)H]17-phenyl PGF(2a) for Bimatoprost. 4) Bimatoprost pretreatment did not attenuate PGF(2alpha)-induced Ca(2+) signals in Swiss 3T3 cells. 5) Regional differences were apparent for Bimatoprost but not FP agonist effects in the cat lung. Bimatoprost reduced intraocular pressure in ocular normotensive and hypertensive monkeys over a 0.001 to 0.1% dose range. A single-dose and multiple-dose ocular distribution/metabolism studies using [(3)H]Bimatoprost (0.1%) were performed. Within the globe, bimatoprost concentrations were 10- to 100-fold higher in anterior segment tissues compared with the aqueous humor. Bimatoprost was overwhelmingly the predominant molecular species identified at all time points in ocular tissues, indicating that the intact molecule reduces intraocular pressure.

Amides↗
PubMed2003

Contribution of ovarian steroid production to urinary estrone conjugate concentrations in Macaca mulatta.

This study was designed to test the hypothesis that basal estrone conjugate (E1C) profiles do not accurately detect ovarian function when ovarian estrogen production is low or absent. We employed surgical removal of active ovaries from laboratory rhesus macaques to simulate an acute decline in ovarian estrogen production. In the first experiment, urine samples collected prior to and following ovariectomy (Ovx) were subjected to high-performance liquid chromatography (HPLC) separation. Eluates were then assayed for E1C immunoreactive components. The results indicated a modest decrease in total immunoreactive polar conjugates following ovariectomy, with no substantial change in the overall retention profile. In the second experiment, estradiol (E2) cypionate injections were used to replace the E2 component of ovarian estrogen production in the treated (Tx) group, while the control group (C) received only vehicle. Urine samples were hydrolyzed and individual estrogens were separated by celite chromatography prior to immuno-assay. Both the Tx and C groups exhibited similar urinary excretion levels of estrone (E1), E2, and E1C prior to Ovx (Pre-Ovx) and after Ovx (Post-Ovx), but there were significant differences between groups after treatment (Post-Tx). Significant differences were observed in the Tx group's excretion of E1, E2, and E1C in the Pre- vs. Post-Ovx samples and in the Post-Ovx and Post-Tx samples. The C group also showed the expected significant differences in the Pre- vs. Post-Ovx samples, as well as in the Pre-Ovx and Post-Tx samples. The results indicate that the use of E1C measurements is clearly a suitable method for monitoring ovarian function in intact, cycling animals, but urinary E2 measurements are required to verify loss of follicular activity.

Animals↗
PubMed2003

Blockade of parathyroid hormone-related protein prevents joint destruction and granuloma formation in streptococcal cell wall-induced arthritis.

OBJECTIVE: To determine whether parathyroid hormone-related protein (PTHrP), an interleukin-1beta-inducible, bone-resorbing peptide that is produced in increasing amounts by the synovium in rheumatoid arthritis (RA), may play a role in the pathophysiology of joint destruction in RA. METHODS: PTHrP expression and the effect of PTHrP 1-34 neutralizing antibody on disease progression were tested in streptococcal cell wall (SCW)-induced arthritis, an animal model of RA. RESULTS: As has been reported in RA, while serum levels of PTHrP did not change during SCW-induced arthritis, PTHrP expression dramatically increased in the arthritic synovium. Treatment with PTHrP neutralizing antibody (versus control antibody) did not affect joint swelling in SCW-treated animals. However, PTHrP antibody significantly inhibited SCW-induced joint destruction, as measured by its ability to block increases in serum pyridinoline (a marker of cartilage and bone destruction), erosion of articular cartilage, decreases in femoral bone mineral density, and increases in the numbers of osteoclasts in eroded bone. Unexpectedly, granuloma formation at sites of SCW deposition in the liver and spleen was also inhibited by PTHrP antibody, an effect associated with significant decreases in the tissue influx of PTH/PTHrP receptor-positive neutrophils and in SCW-induced neutrophilia. In vitro, neutrophil chemotaxis was stimulated by PTHrP 1-34. CONCLUSION: These findings suggest that PTHrP, consistent with its previously described osteolytic effects in metastatic bone disease, can also be an important mediator of joint destruction in inflammatory bone disorders, such as RA. Moreover, this study reveals heretofore unknown effects of PTHrP peptides on neutrophil function that could have important implications in the pathogenesis of inflammatory granulomatous disorders.

Amino Acids↗
PubMed2003

Sequence analysis demonstrates that Onion yellow dwarf virus isolates from China contain a P3 region much larger than other potyviruses.

The complete sequence of an isolate of Onion yellow dwarf virus (OYDV) from Yuhang, Zhejiang province, China, was determined. It was 10538 nts in length and was predicted to encode a polyprotein 3403 amino acids (aa) long with a calculated M(r) of 385.1 kDa. The predicted P3 protein (530 aa) was larger than that of any of the potyviruses sequenced to date (344-378 aa). The additional sequence occurs at the N-terminus of the protein, does not represent a duplication from elsewhere in the OYDV genome and could not be matched to any other sequences in the databases. Similar sequences were found in 4 other Chinese OYDV isolates. Phylogenetic analysis of the amino acid sequences of the polyprotein showed that OYDV is distantly related to Pea seed-borne mosaic virus and the potyviruses of grasses and cereals.

Amino Acid Sequence↗
PubMed2003

Estrogen levels and estrogen receptors in patients with stress urinary incontinence and pelvic organ prolapse.

OBJECTIVES: To investigate the histologic characteristics of tissues presumed to be the cause of urinary stress incontinence and pelvic organ prolapse. METHODS: Cardinal ligament and uterosacral ligament samples were obtained from 73 women undergoing hysterectomy. The evaluation of estrogen receptors (ERs) by immunohistochemical staining was semi-quantitative. Serum estrogen was determined by ELISA. Statistical analyses were performed by the independent-sample t-test and one-way ANOVA. RESULTS: Serum estradiol levels and ER values in the premenopausal women with pelvic organ prolapse were significantly lower than in the control group (P<0.01). A positive correlation was found between ERs and the number of postmenopausal years (P<0.01). ER values were similar in the cardinal and uterosacral ligaments. CONCLUSIONS: Serum estrogen levels and ER values are significantly lower in the uterine ligaments of premenopausal women with pelvic organ prolapse, and there was a positive correlation between ER values in the uterine ligaments and the duration of postmenopausal years. Serum estrogen levels and ER values were similar in the cardinal ligament and the uterosacral ligament.

Adult↗
PubMed2003

Curcumin enhances the immunosuppressive activity of cyclosporine in rat cardiac allografts and in mixed lymphocyte reactions.

Curcumin (CCM; diferuoylmethane) is a dietary pigment in curry with known antineoplastic and anti-inflammatory effects. The immunosuppressive effects of CCM were studied in (1) rat heterotopic cardiac transplant models, using Brown-Norway (BN, RT1(n)) hearts to WKY (RT1(u)) hosts or Buffalo (BUF, RT1(b)) hearts to Wistar-Furth (WF, RT1(u)) hosts, (2) reverse transcriptase-polymerase chain reaction analysis of cytokines from transplanted specimens, and (3) mixed lymphocyte reactions (MLR). In the BN-to-WKY model, CCM alone significantly increased the mean survival time (MST) to 20.5 to 24.5 days, as compared to 9.1 days among nontreated controls. The combination of CCM and subtherapeutic doses of CsA produced further prolongation of the MST to 28.5 to 35.6 days, better than that of CCM or CsA alone (P <.05). In a BUF-to-WF model, CCM alone did not increased the MST, unless it was combined with subtherapeutic doses of CsA, wherein two thirds of the grafts survived for more than 60 days (P <.05 as compared to either treatment group). Cytokine analysis revealed significantly reduced expression of interleukin-2 (IL-2), interferon-gamma (IFN-gamma) and granzyme B in the day 3 specimens of the CCM and CCM CsA-treated allografts compared with the nontreated allograft controls. MLRs using the two MHC-incompatible rat strains (BNxWKY) showed an effect of increasing concentrations of CCM and/or CsA, which by combination index (CI) analysis showed a synergistic effect (CI = 0.22 to 0.81). This study for the first time demonstrates the effectiveness of CCM as a novel adjuvant immunosuppressant with cyclosporine both in vivo and in vitro.

Animals↗
PubMed2003

Fas siRNA reduces apoptotic cell death of allogeneic-transplanted hepatocytes in mouse spleen.

BACKGROUND: Synthetic siRNAs 21 to 23 nucleotides in length silence gene expression posttranscriptionally, and RNA interference targeting Fas protects mice from fulminant hepatitis. Fas-mediated apoptosis has also been implied in the mechanism of hepatocyte apoptosis upon allogenic hepatocyte transplantation (HTx), and blockade of Fas and Fas ligand interaction successfully promotes the repopulation of allogenic liver cells in recipient spleens. In the present study, we further investigated the protective effects of Fas silencing on allogeneic hepatocytes transplanted into mouse spleens. MATERIALS AND METHODS: Hepatocytes were isolated from BALB/c mice and mock transfected or transfected with Fas siRNA or GFP siRNA (n = 8/group). The expression of Fas was examined by RT-PCR and flow cytometric analysis. Forty-eight hours later, the cells were transplanted into spleens of allogenic B6 mice. Spleens were harvested on day 21 after transplantation. Apoptosis was assessed by TUNEL assay, survival of hepatocytes by alanine transaminase (ALT) assay. RESULTS: Fas siRNA transfection reduced Fas expression on hepatocytes at both mRNA and protein levels (P <.05). Upon transplanting into recipient spleens, hepatocytes transfected with Fas siRNA demonstrated a lower percentage of apoptosis detected by TUNEL (6 +/- 3% in Fas siRNA group vs 12 +/- 5% in GFP siRNA group and 10 +/- 3% in mock transfected group; P <.05), and increased survival as determined by ALT assay (38.2 +/- 10.6 IU/g in Fas siRNA group vs 21.3 +/- 8.4 IU/g in GFP siRNA group and 18.5 +/- 5.9 IU/g in mock-transfected animals). CONCLUSIONS: Fas silencing by RNA interference reduces apoptosis and increases survival of allogenic transplanted hepatocytes, and thus holds promise to inhibit acute rejection after hepatocyte transplantation.

Animals↗
PubMed2003

Blocker-resistant Ca2+ currents in rat CA1 hippocampal pyramidal neurons.

Ca(2+) currents resistant to organic Ca(2+) channel antagonists are present in different types of central neurons. Here, we describe the properties of such currents in CA1 neurons acutely dissociated from rat hippocampus. Blocker-resistant Ca(2+) currents were isolated by combined application of N-, P/Q- and L-type Ca(2+) current antagonists (omega-conotoxin GVIA 2 microM; omega-conotoxin MVIIC 3 microM; omega-agatoxin IVA 200 nM; nifedipine 10 microM) and constituted approximately 21% of the total Ba(2+) current. The blocker-resistant current showed properties similar to R-type currents in other cell types, i.e. voltages of half-maximal inactivation and activation of -76 and -17 mV, respectively, and strong inactivation during the test pulse. In addition, blocker-resistant Ca(2+) currents in CA1 neurons displayed a characteristically rapid deactivation. Application of mock action potentials revealed that charge transfer through blocker-resistant Ca(2+) channels is highly sensitive to action potential shape and changes in resting membrane voltage. Pharmacological experiments showed that these currents were highly sensitive to the divalent cation Ni(2+) (half-maximal block at 28 microM), but were relatively resistant to the spider toxin SNX-482 (8% and 52% block at 0.1 and 1 microM, respectively). In addition to the functional analysis, we examined the expression of pore-forming and accessory Ca(2+) channel subunits on the messenger RNA level in isolated CA1 neurons using quantitative real-time polymerase chain reaction. Of the pore-forming alpha subunits encoding high-threshold Ca(2+) channels, Ca(v)2.1, Ca(v)2.2 and Ca(v)2.3 messenger RNA levels were most prominent, corresponding to the high proportion of N-, P/Q- and R-type currents in these neurons. In summary, CA1 neurons display blocker-resistant Ca(2+) currents with distinctive biophysical and pharmacological properties similar to R-type currents in other neuron types, and express Ca(2+) channel messenger RNAs that give rise to R-type Ca(2+) currents in expression systems.

Animals↗
PubMed2003

Molecular and functional changes in voltage-dependent Na(+) channels following pilocarpine-induced status epilepticus in rat dentate granule cells.

Status epilepticus (S.E.) is known to lead to a large number of changes in the expression of voltage-dependent ion channels and neurotransmitter receptors. In the present study, we examined whether an episode of S.E. induced by pilocarpine in vivo alters functional properties and expression of voltage-gated Na(+) channels in dentate granule cells (DGCs) of the rat hippocampus. Using patch-clamp recordings in isolated DGCs, we show that the voltage-dependent inactivation curve is significantly shifted toward depolarizing potentials following S.E. (half-maximal inactivation at -43.2+/-0.6 mV) when compared with control rats (-48.2+/-0.8 mV, P<0.0001). The voltage-dependent activation curve is significantly shifted to more negative potentials following S.E., with half-maximal activation at -28.6+/-0.8 mV compared with -25.8+/-0.9 mV in control animals (P<0.05). The changes in voltage dependence resulted in an augmented window current due to increased overlap between the activation and inactivation curve. In contrast to Na(+) channel voltage-dependence, S.E. caused no changes in the kinetics of fast or slow recovery from inactivation. The functional changes were accompanied by altered expression of Na(+) channel subunits measured by real-time reverse transcription-polymerase chain reaction in dentate gyrus microslices. We investigated expression of the pore-forming alpha subunits Na(v)1.1-Na(v)1.3 and Na(v)1.5-Na(v)1.6, in addition to the accessory subunits beta(1) and beta(2). The Na(v)1.2 and Na(v)1.6 subunit as well as the beta(1) subunit were persistently down-regulated up to 30 days following S.E. The beta(2) subunit was transiently down-regulated on the first and third day following S.E. These results indicate that differential changes in Na(+) channel subunit expression occur in concert with functional changes. Because coexpression of beta subunits is known to robustly shift the voltage dependence of inactivation in a hyperpolarizing direction, we speculate that a down-regulation of beta-subunit expression may contribute to the depolarizing shift in the inactivation curve following S.E.

Animals↗
PubMed2003

Differential antinociceptive effects induced by a selective cyclooxygenase-2 inhibitor (SC-236) on dorsal horn neurons and spinal withdrawal reflexes in anesthetized spinal rats.

The aim of present study was to examine the effect of a selective cyclooxygenase-2 (COX-2) inhibitor SC-236 (4 mg/kg) on the simultaneous responsiveness of spinal wide-dynamic range (WDR) neurons and single motor units (SMUs) from gastrocnemius soleus muscles to mechanical stimuli (pressure and pinch) and repeated suprathreshold (1.5xT, the intensity threshold) electrical stimuli with different frequencies (3 Hz, 20 Hz) under normal conditions and bee venom (BV, 0.2 mg/50 microl)-induced inflammation and central sensitization. During normal conditions, the responses of SMUs, but not WDR neurons, to mechanical and repeated electrical stimuli (3 Hz, wind-up) were depressed by systemic administration of SC-236 as well as its vehicle (100% dimethyl sulfoxide (DMSO)). The after-discharges of both the WDR neurons and the simultaneously recorded SMUs after electrical stimuli with 20 Hz were markedly depressed only by SC-236, indicating that the mechanisms underlying the generation of the C-fiber mediated late responses and the after-discharges may be different. The enhanced responsiveness of both WDR neurons and SMUs to mechanical pressure stimuli (allodynia) and pinch stimuli (hyperalgesia) in the BV experiments was apparently depressed by SC-236, but not its vehicle. For electrical stimulation, the enhanced late responses and after-discharges, but not early responses, of both the WDR neurons and the simultaneously recorded SMUs were markedly depressed only by SC-236. This indicates that different central pharmacological mechanisms underlie the generation of these enhanced early, late responses, and after-discharges during BV-induced inflammation. The data suggest that the COX-2 inhibitor SC-236 apparently depress the activities of both spinal cord dorsal horn neuron and spinal withdrawal reflex during BV-induced sensitization, indicating that COX-2 plays an important role in the maintenance of central sensitization.

Action Potentials↗
PubMed2003

Dosage and characterization of circulating DNA: present usage and possible applications in systemic autoimmune disorders.

The discovery of extracellular nucleic acids in the circulation was firstly reported in 1948. In the last few years it has been demonstrated that the entire spectrum of genetic changes seen in primary tumors could also be detected in the serum of patients with solid tumors. This observation has also opened up exciting possibilities for tumor detection and monitoring. More recently investigators started looking for other forms of non-host DNA in the plasma/serum so that in 1997 the presence of fetal DNA in the plasma/serum of pregnant women was demonstrated. This finding suggested that maternal plasma fetal DNA would be a very valuable material for noninvasive prenatal diagnosis and monitoring. It has been also postulated that the presence of the two-way trafficking of nucleated cells and free DNA between the mother and fetus may have potential implications for the development of certain autoimmune diseases. Concerning autoimmune disorders, Tan was the first author to describe the presence of high levels of circulating DNA in patients with systemic lupus erythematosus (SLE) in 1986. Later on different authors demonstrated that elevated levels of serum DNA was also present in patients with other diseases including rheumatoid arthritis. We have analyzed both circulating free DNA and DNA extracted from nucleated blood cells in scleroderma and in lupus patients but, by using gel electrophoresis, we were able to define the pattern of the DNA, instead of simply dosing its amount in the circulation. We have found that SLE and SSc have anomalous patterns of DNA both in serum and in the Buffy-coat and that these patterns are typical for each disorder. It is possible that understanding the biological significance of the diversity in DNA pattern exhibition in white blood cells may give new insights into the pathophysiology of autoimmune disorders. It is also conceivable that circulating and immune-competent cellular DNA markers might offer the promise of precise quantitative analysis useful for diagnostic purposes, without the need to establish difficult cutoffs as is necessary for protein markers.

Adolescent↗
PubMed2003

The inhibitory effect of VitD3 on proliferation of keratinocyte cell line HACAT is mediated by down-regulation of CXCR2 expression.

Psoriasis is a disease characterized by inflammation and increased population of hyperproliferative keratinocytes. It is well known that chemokines and chemokine receptors, such as interleukin-8 and its receptors (CXCR1 and CXCR2), play important roles in the pathogenesis of psoriasis. So far, examination of CXCR2 expression in psoriatic lesional keratinocytes by FACS calibur has not been reported and whether VitD3 inhibits psoriatic lesional keratinocyte proliferation through down-regulation of CXCR2 expression has not been elucidated. In the present study, CXCR2 expression in psoriatic lesional keratinocytes and HACAT treated with VitD3 was detected by flow cytometry. The proliferative capacity of HACAT treated with VitD3 was assayed by MTT assay. The results showed that CXCR2 expression in psoriatic lesional keratinocytes was higher than that in normal human keratinocytes. At the correct concentration VitD3 could inhibit human keratinocyte proliferation and down-regulate CXCR2 expression in HACAT. The data demonstrate that the inhibitory effect of VitD3 on keratinocyte proliferation might be mediated by down-regulation of CXCR2 expression.

Administration, Topical↗
PubMed2003

Comparison of the expression of Bacillus thuringiensis full-length and N-terminally truncated vip3A gene in Escherichia coli.

AIMS: Studies were performed to demonstrate the function of the putative signal peptide of Vip3A proteins in Escherichia coli. METHODS AND RESULTS: The full-length vip3A-S184 gene was isolated from a soil-isolated Bacillus thuringiensis, and the vip3AdeltaN was constructed by deleting 81 nucleotides at the 5'-terminus of vip3A-S184. Both were transformed and expressed in E. coli. About 19.2% of Vip3A-S184 proteins secreted soluble proteins and others formed inclusion bodies in the periplasmic space. In contrast, the Vip3AdeltaN was insoluble and formed inclusion bodies in the cytoplasm. Bioassay indicated that Vip3A-S184 showed different toxicity against Spodoptera exigua, Helicoverpa armigera and S. litura, but Vip3AdeltaN showed no toxicity to either of them because of the deletion of the first 27 amino acids at the N-terminus. CONCLUSIONS: The results suggest that the deleted N-terminal sequences were essential for the secretion of Vip3A-S184 protein in E. coli and might be required for toxicity. SIGNIFICANCE AND IMPACT OF THE STUDY: The function of the putative signal peptide of Vip3A protein in E. coli was investigated. These would be helpful to make clear the unknown secretion pathway of Vip3A protein in B. thuringiensis and determine the receptor-binding domain or toxic fragment of Vip3A-S184 protein.

Amino Acid Sequence↗