Biomedical subjects

Sheridan Henness

Publications and source records attributed to Sheridan Henness.

11 recordsLinked to original sources

PubMed2006

Gingerol metabolite and a synthetic analogue Capsarol inhibit macrophage NF-kappaB-mediated iNOS gene expression and enzyme activity.

Ginger (Zingiber officinale) is widely used in traditional Chinese medicine, with beneficial effects reported in numerous diseases, including inflammation. Inducible nitric oxide synthase (iNOS), a proinflammatory enzyme responsible for the generation of nitric oxide (NO), has been implicated in the pathogenesis of inflammatory diseases. Gingerols, the main pungent principles of ginger, have anti-inflammatory properties in vitro. In this study we examine the inhibitory effect of a stable [6]-gingerol metabolite, RAC-[6]-dihydroparadol ([6]-DHP) and a closely related gingerol analogue, RAC-2-hydroxy-1-(4-hydroxy-3-methoxyphenyl)dodecan-3-one [a capsaicin/gingerol (Capsarol) analogue referred to as ZTX42] on NO production, inducible nitric oxide synthase (iNOS) activity and protein expression levels in a murine macrophage cell line, RAW 264.7. Both ZTX42 and [6]-DHP significantly inhibited lipopolysaccharide-induced NO production in a concentration-dependent manner, with an IC (50) of 1.45 +/- 0.03 microM and 7.24 +/- 0.22 microM, respectively (P < 0.05). Although both compounds partially inhibited the catalytic activity of iNOS, their inhibitory effect was predominantly due to attenuation of iNOS protein production. This occurred at the transcriptional level, since the gingerol compounds decreased LPS-induced IkappaB-alpha degradation, prevented nuclear translocation of NF-kappaB p65 and reduced NF-kappaB activity in a concentration-dependent manner. Taken together, these results show that ZTX42 and [6]-DHP suppress NO production in murine macrophages by partially inhibiting iNOS enzymatic activity and reducing iNOS protein production, via attenuation of NF-kappaB-mediated iNOS gene expression, providing a rationale for the anti-inflammatory activity reported for this class of compounds.

Animals↗

PubMed2006

IL-17A acts via p38 MAPK to increase stability of TNF-alpha-induced IL-8 mRNA in human ASM.

Human airway smooth muscle (ASM) plays an immunomodulatory role in asthma. Recently, IL-17A has become of increasing interest in asthma, being found at elevated levels in asthmatic airways and emerging as playing an important role in airway neutrophilia. IL-17A predominantly exerts its neutrophil orchestrating role indirectly via the induction of cytokines by resident airway structural cells. Here, we perform an in vitro study to show that although IL-17A did not induce secretion of the CXC chemokine IL-8 from ASM cells, IL-17A significantly potentiates TNF-alpha-induced IL-8 protein secretion and gene expression in a concentration- and time-dependent manner (P < 0.05). Levels of IL-8 protein produced after 24 h of incubation with TNF-alpha were enhanced 2.7-fold in the presence of IL-17A, and conditioned media significantly enhanced neutrophil chemotaxis in vitro. As IL-17A had no effect on the activity of NF-kappaB, a key transcriptional regulator of IL-8 gene expression, we then examined whether IL-17A acts at the posttranscriptional level. We found that IL-17A significantly augmented TNF-alpha-induced IL-8 mRNA stability. Interestingly, this enhanced stability occurred via a p38 MAPK-dependent pathway. The decay of IL-8 mRNA transcripts proceeded at a significantly faster rate when cells were pretreated with the p38 MAPK inhibitor SB-203580 (-0.05763 +/- 0.01964, t(1/2) = 12.0 h), compared with vehicle (-0.01030 +/- 0.007963, t(1/2) = 67.3 h) [results are expressed as decay constant (means +/- SE) and half-life (t(1/2) in h): P < 0.05]. Collectively, these results demonstrate that IL-17A amplifies the synthetic function of ASM cells, acting via a p38 MAPK-dependent posttranscriptional pathway to augment TNF-alpha-induced secretion of the potent neutrophil chemoattractant IL-8 from ASM cells.

Bronchi↗

PubMed2006

Gadofosveset.

Gadofosveset is the first gadolinium-based magnetic resonance (MR) imaging agent designed to image the blood pool. At clinically relevant concentrations, gadofosveset is highly bound to human serum albumin, which has the effect of increasing its signal-enhancing properties above that of non-protein bound imaging agents, as well as increasing its plasma half-life, allowing for increased imaging times. The use of gadofosveset-enhanced MR angiography was compared with non-enhanced MR angiography in four open-label, multicentre studies in adults with known or suspected arterial disease. Significant improvements in the accuracy and specificity of diagnosis were seen with gadofosveset in patients with aortoiliac disease in two studies. Sensitivity was also improved, with all three readers in one study, and two of three readers in the other study, showing significant improvements with gadofosveset use. Significant improvements in sensitivity, specificity, and accuracy were also seen with gadofosveset in a renal artery disease study. Specificity was significantly improved in patients with pedal artery disease across all readers, with accuracy and sensitivity significantly improved in two of three and one of three readers. Gadofosveset was generally well tolerated in clinical trials, with most adverse events being mild or moderate in severity.

Adult↗

PubMed2006

Orlistat: a review of its use in the management of obesity.

Orlistat (Xenical) is a reversible inhibitor of gastric and pancreatic lipases. In conjunction with a hypocaloric diet and moderate exercise, orlistat is an effective drug for use in the management of obesity in adults with or without comorbidities. Recent data have shown that orlistat is also effective as a component of weight management strategies in obese adolescents. In addition to its well established efficacy in achieving modest weight loss, orlistat has been shown to improve glycaemic parameters in obese adults with type 2 diabetes mellitus as well as some features of the metabolic syndrome. Orlistat is generally well tolerated. Thus, orlistat is an option for the treatment of obese patients with or without type 2 diabetes and also has a role in the management of obese patients with the metabolic syndrome, associated comorbidities or concomitant disorders.

Adolescent↗

PubMed2006

Vildagliptin.

Vildagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor that is being evaluated in the treatment of patients with type 2 diabetes mellitus. It improves glycaemic control by inhibiting DPP-4 from inactivating the incretin hormones glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide, prolonging incretin activity in response to ingestion of nutrients. This allows for increased insulin sensitivity, decreased glucagon secretion and improved beta-cell function in a glucose-dependent manner. Glycaemic control with vildagliptin 50 or 100 mg/day, measured by a change from baseline in mean glycosylated haemoglobin (HbA(1c)) at study endpoint, was improved relative to placebo in several well designed clinical trials of vildagliptin monotherapy in patients with type 2 diabetes. In randomised active comparator studies, noninferiority of vildagliptin in reducing HbA(1c) levels from baseline was established to rosiglitazone, but not to metformin. Vildagliptin also showed efficacy in reducing HbA(1c) levels in patients with type 2 diabetes when used in combination with metformin, pioglitazone or insulin. Vildagliptin was generally well tolerated when administered alone or in combination with additional antidiabetic treatment. Gastrointestinal adverse events were mild to moderate in intensity, and occurred less frequently than with metformin. Hypoglycaemic events were rare and occurred at a similar incidence to that with placebo.

Adamantane↗

PubMed2006

Rimonabant.

Rimonabant is the first of a new class of selective cannabinoid receptor-1 blockers. It reduces the overactivity of the endocannabinoid system, improving lipid and glucose metabolism and regulating food intake and energy balance. In four randomised, double-blind clinical trials in overweight or obese adults with or without type 2 diabetes and/or dyslipidaemia, oral rimonabant 20mg once daily reduced weight and waist circumference to a significantly greater extent than placebo. A significantly greater proportion of rimonabant than placebo recipients achieved the clinically significant weight-loss target of > or =5% or > or =10% of initial weight. Rimonabant was associated with significant improvements in glycaemic control relative to placebo, with approximately equal to 57% of the reduction in glycosylated haemoglobin being independent of the effects of weight loss in one trial. Improvements in other cardiometabolic risk factors (i.e. increases in high-density lipoprotein-cholesterol [HDL-C] and decreases in triglyceride [TG] levels) were significantly greater with rimonabant than with placebo. The improvement in lipid profile also demonstrated a weight-independent effect, with approximately equal to 47-58% of the improvement in HDL-C and TG being beyond that expected through weight loss alone. Rimonabant was generally well tolerated, with most adverse events considered mild to moderate in severity.

Adult↗

PubMed2004

IL-17A augments TNF-alpha-induced IL-6 expression in airway smooth muscle by enhancing mRNA stability.

BACKGROUND: IL-17A is implicated in the regulation of inflammation and is found in increased amounts in the asthmatic airway. Human airway smooth muscle (ASM) cells synthesize cell adhesion molecules and cytokines in response to inflammatory mediators. OBJECTIVE: In this study, we examined whether IL-17A modulated the synthetic function of ASM cells. METHODS: Primary ASM cultures were treated with IL-17A alone and in combination with the proinflammatory cytokines TNF-alpha and IL-1beta. Intercellular adhesion molecule 1 expression, GM-CSF, and IL-6 secretion were measured by ELISA. Examination of transcriptional regulation was performed via transient transfection of promoter constructs, whereas mRNA stability was assessed by actinomycin D chase and quantitative real-time PCR. RESULTS: Airway smooth muscle did not secrete IL-17A after stimulation of ASM with TNF-alpha and IL-1beta. Furthermore, IL-17A (0.1-10 ng/mL) had no effect on TNF-alpha-induced and IL-1beta-induced intercellular adhesion molecule 1 expression or GM-CSF secretion. However, IL-17A (10 ng/mL) significantly augmented TNF-alpha-induced IL-6 secretion 12-fold (TNF-alpha, 2.3 +/- 0.4 ng/mL; IL-17A and TNF-alpha, 27.5 +/- 4.8 ng/mL; P <.05) while having no effect on IL-1beta-induced IL-6. Although IL-17A had no effect on nuclear factor kappaB-mediated transcriptional regulation of IL-6 gene expression induced by TNF-alpha, IL-17A significantly augmented TNF-alpha-induced IL-6 mRNA stability. CONCLUSION: Collectively, these results demonstrate that IL-17A amplifies the synthetic function of ASM cells, acting via a posttranscriptional pathway, rather than transcriptional mechanisms, to augment TNF-alpha-induced secretion of IL-6 from ASM cells.

Bronchi↗

PubMed2004

Changes in gene expression associated with stable drug and radiation resistance in small cell lung cancer cells are similar to those caused by a single X-ray dose.

Small cell lung cancer (SCLC) initially responds well to chemotherapy and fractionated radiotherapy, but resistance to these treatments eventually develops in the vast majority of cases. To understand how resistance develops in the H69 SCLC cell line, we compared the changes in gene expression associated with 37.5 Gy fractionated X-ray treatment that produced the stable radiation- and drug-resistant H69/R38 cell subline to the changes associated with a single 4- or 8-Gy X-ray treatment. Gene expression was determined by suppression subtractive hybridization combined with Northern blot analysis and two-dimensional (2D) protein electrophoresis. Stable radiation and drug resistance was associated with coordinate changes in the expression of genes of the cytoskeleton, protein synthesis, cell cycle, redox/stress and metabolic pathways. The pattern of these changes was remarkably similar to the changes seen 24 h after a single X-ray treatment of the H69 cells but differed from the changes in expression associated with a single X-ray treatment of the resistant H69/ R38 cells. Stable radiation and drug resistance may be caused by the constitutive expression of those genes transiently expressed by sensitive cells in response to a single X-ray dose. The repeated treatments received during fractionated irradiation may promote the change from a transient to a constitutive pattern of gene expression.

Carcinoma, Small Cell↗

PubMed2003

Gypenosides derived from Gynostemma pentaphyllum suppress NO synthesis in murine macrophages by inhibiting iNOS enzymatic activity and attenuating NF-kappaB-mediated iNOS protein expression.

Gypenosides isolated from Gynostemma pentaphyllum are widely used in traditional Chinese medicine, with beneficial effects reported in numerous diseases, including inflammation and atherosclerosis, although the mechanism underlying these therapeutic effects is unknown. Because increased nitric oxide (NO) plays a role in these pathological conditions, we investigated whether the pharmacological activity of gypenosides is due to suppression of NO synthesis. The markedly increased production of nitrite by stimulation of RAW 264.7 murine macrophages with 1 microg/mL lipopolysaccharide (LPS) for 20 h (unstimulated: 0.3+/-0.3 microM vs. LPS: 32.5+/-1.2 microM) was dose-dependently inhibited by gypenosides (0.1-100 microg/mL). When cells were pretreated with gypenosides (for 1h) prior to LPS stimulation, subsequent NO production was significantly attenuated (IC(50) of 3.1+/-0.4 microg/mL) (P<0.05). Gypenosides (25 microg/mL) produced the same maximum inhibition of LPS-induced NO production as aminoguanidine, a standard inhibitor of NOS enzymes. Suppression of NO production occurred both by direct inhibition of the activity and expression of iNOS. Inhibition of iNOS protein expression appears to be at the transcriptional level, since gypenosides decreased LPS-induced NF-kappaB activity in a dose-dependent manner (P<0.05), with significant inhibition achieved following pretreatment with 10 microg/mL gypenoside. Taken together, these results suggest that gypenosides derived from G. pentaphyllum suppress NO synthesis in murine macrophages by inhibiting iNOS enzymatic activity and attenuating NF-kappaB-mediated iNOS protein expression, thereby implicating a mechanism by which gypenosides may exert their therapeutic effects.

Animals↗

PubMed2002

Fractionated irradiation of H69 small-cell lung cancer cells causes stable radiation and drug resistance with increased MRP1, MRP2, and topoisomerase IIalpha expression.

PURPOSE: After standard treatment with chemotherapy and radiotherapy, small-cell lung cancer (SCLC) often develops resistance to both treatments. Our aims were to establish if fractionated radiation treatment alone would induce radiation and drug resistance in the H69 SCLC cell line, and to determine the mechanisms of resistance. METHODS AND MATERIALS: H69 SCLC cells were treated with fractionated X-rays to an accumulated dose of 37.5 Gy over 8 months to produce the H69/R38 subline. Drug and radiation resistance was determined using the MTT (3,-4,5 dimethylthiazol-2,5 diphenyltetrazolium bromide) cell viability assay. Protein expression was analyzed by Western blot. RESULTS: The H69/R38 subline was resistant to radiation (2.0 +/- 0.2-fold, p < 0.0001), cisplatin (14 +/- 7-fold, p < 0.001), daunorubicin (6 +/- 3-fold, p < 0.05), and navelbine (1.7 +/- 0.15-fold, p < 0.02). This was associated with increased expression of the multidrug resistance-associated proteins, MRP1 and MRP2, and topoisomerase IIalpha and decreased expression of glutathione-S-transferase pi (GSTpi) and bcl-2 and decreased cisplatin accumulation. Treatment with 4 Gy of X-rays produced a 66% decrease in MRP2 in the H69 cells with no change in the H69/R38 cells. This treatment also caused a 5-fold increase in topoisomerase IIalpha in the H69/R38 cells compared with a 1.5-fold increase in the H69 cells. CONCLUSIONS: Fractionated radiation alone can lead to the development of stable radiation and drug resistance and an altered response to radiation in SCLC cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Cellular models of drug- and radiation-resistant small cell lung cancer.

BACKGROUND: The H69-EPR, H69-CP, H69-VP and H69/R38 resistant sublines of the classic small cell lung cancer (SCLC) line have proven useful in studies of resistance and its circumvention with paclitaxel. MATERIALS AND METHODS: The suppressor/oncogene profile of these sublines determined by Western and Northern blot was compared to the variant H82 SCLC cell profile. Two-dimensional electrophoresis/mass spectrometry was used to determine the effect of paclitaxel on protein expression. RESULTS: The H69-EPR and H69-CP resistant sublines were similar to the variant H82 cells for bcl-2, p21waf1, p53, N-myc and c-myc expression while the H69-VP subline retained the classic H69 pattern. A 1-h treatment with 10 ng/ml paclitaxel substantially reversed the resistance except for the H69/R38 subline and tended to reverse the resistance-associated changes in protein expression in the H69-EPR subline. CONCLUSION: Although some resistant sublines express a variant pattern of suppressor/oncogenes with low bcl-2, resistance is substantially reversed by paclitaxel treatment.

Antineoplastic Agents, Phytogenic↗