Search results for "Steroid"
showing 10 items of 1005 documents
Some effects of salmon calcitonin on calcium metabolism in the crustaceanOrchestia during the molt cycle
1989
In the terrestrial amphipod Orchestia cavimana, investigations of the variations of the total hemolymphatic calcium during the normal molt cycle revealed that a calcium balance is maintained in intermolt, as observed in numerous crustaceans. During premolt, hypercalcemia occurs, related to the marked calcium reabsorption from the old cuticle, which may promote the storage of a part of this calcium within the midgut posterior caeca. The calcium levels fall after exuviation to late postmolt to the low basal levels of intermolt; this may reflect the imbalance between the rates of calcification of the newly secreted cuticle and uptake of calcium within the posterior caeca. Administration of sal…
Notes on some Late Cretaceous goniasterid starfish (Echinodermata, Asteroidea) from Belgium and Germany
2021
Both partially articulated specimens and dissociated marginal ossicles form the basis for erection of two new species of Late Cretaceous goniasterids from the Mons and Liège-Limburg basins (Belgium) and the Hannover area (Germany). Chomataster breizh sp. nov., which recalls the type species, Chomataster acules Spencer, 1913, but differs in several respects, is based on a partial external mould of the marginal frame of disc and arms in flint (upper Campanian Spiennes Chalk Formation; Mons Basin), as well as on a more or less complete individual, preserving small, spherical spines and granules and encased in a flint nodule from the upper Maastrichtian Nekum Member (Maastricht Formation; Liège…
Immunomodulation and Anti-inflammatory Roles of Polyphenols as Anticancer Agents
2011
Cancers are the largest cause of mortality and morbidity in industrialized countries. Several new concepts have emerged in relation to mechanisms that contribute to the regulation of carcinogenesis processes and associated inflammatory effects such as the modulation of innate immune cells and adaptive immune cells that could infiltrate the tumor. In the tumor microenvironment, there is a delicate balance between antitumor immunity and tumor-originated proinflammatory activity, which weaken antitumor immunity. Consequently; modulation of immune cells and inflammatory processes represent attractive targets for therapeutic intervention in malignant diseases with the goal to restore the sensiti…
Development of hydroxysteroid sulfotransferase-deficient lesions during hepatocarcinogenesis in rats
1993
Rat liver cytosolic hydroxysteroid sulfotransferases form highly reactive sulfuric acid esters from some benzylic alcohols, such as 1-hydroxymethylpyrene. In this study we examined the expression of hydroxysteroid sulfotransferase a (STa) in carcinogen-induced enzyme-altered, presumably preneoplastic, rat liver foci. Female Wistar rats were given a single i.p. injection of diethylnitrosamine (0.15 mumol/g body wt) 1 day after birth to induce the liver foci. After weaning, rats were given 1-hydroxymethylpyrene or phenobarbital continuously in their diet (250 or 500 p.p.m. respectively) for a total of 120 days. Carcinogen-induced liver foci were identified by a change in the marker enzyme ade…
Parthenolide induces superoxide anion production by stimulating EGF receptor in MDA-MB-231 breast cancer cells
2013
The sesquiterpene lactone parthenolide (PN) has recently attracted considerable attention because of its anti-microbial, anti-inflammatory and anticancer effects. However, the mechanism of its cytotoxic action on tumor cells remains scarcely defined. We recently provided evidence that the effect exerted by PN in MDA-MB-231 breast cancer cells was mediated by the production of reactive oxygen species (ROS). The present study shows that PN promoted the phosphorylation of EGF receptor (phospho-EGFR) at Tyr1173, an event which was observed already at 1 h of incubation with 25 µM PN and reached a peak at 8-16 h. This effect seemed to be a consequence of ROS production, because N-acetylcystein…
The oxygen radicals involved in the toxicity induced by parthenolide in MDA-MB-231 cells
2014
It has been shown that the sesquiterpene lactone parthenolide lowers the viability of MDA-MB-231 breast cancer cells, in correlation with oxidative stress. The present report examined the different radical species produced during parthenolide treatment and their possible role in the toxicity caused by the drug. Time course experiments showed that in the first phase of treatment (0-8 h), and in particular in the first 3 h, parthenolide induced dichlorofluorescein (DCF) signal in a large percentage of cells, while dihydroethidium (DHE) signal was not stimulated. Since the effect on DCF signal was suppressed by apocynin and diphenyleneiodonium (DPI), two inhibitors of NADPH oxidase (NOX), we s…
Cyclooxygenases in hepatocellular carcinoma
2006
Many epidemiological studies demonstrate that treatment with non-steroidal anti-inflammatory drugs (NSAIDs) reduce the incidence and mortality of certain malignancies, especially gastrointestinal cancer. The cyclooxygenase (COX) enzymes are well-known targets of NSAIDs. However, conventional NSAIDs non-selectively inhibit both the constitutive form COX-1, and the inducible form COX-2. Recent evidence indicates that COX-2 is an important molecular target for anticancer therapies. Its expression is undetectable in most normal tissues, and is highly induced by pro-inflammatory cytokines, mitogens, tumor promoters and growth factors. It is now well-established that COX-2 is chronically overexpr…
Re-expression of C/EBP alpha induces CYP2B6, CYP2C9 and CYP2D6 genes in HepG2 cells.
1998
Cytochrome P450 (CYP) activity is very low or even absent in human hepatomas, a phenomenon that is accompanied by low levels of some liver transcription factors, notably C/EBP alpha. To investigate a possible link between this transcription factor and hepatic CYP expression, we have stably transfected HepG2 cells with a C/EBP alpha vector containing a Zn-inducible metallothionein promoter. Expression of functional C/EBP alpha up to liver levels concomitantly increased the mRNAs of several members of the CYP2 family (2B6, 2C9 and 2D6), suggesting that this transcription factor may play a relevant role in controlling the hepatic expression of CYP enzymes.
Induction of apoptosis and inhibition of cell growth in human hepatocellular carcinoma cells by COX-2 inhibitors
2005
The aim of the present study was to examine the effects of nonselective (indomethacin) and selective cyclooxygenase-2 (COX-2) inhibitors (NS-398, nimesulide, and CAY10404) on cell growth, cell cycle distribution, and apoptosis in three human hepatocellular carcinoma cell lines (HepG2, HuH-6, and HA22T/VGH) with different characteristics of differentiation and biological behavior. The four COX inhibitors showed a dose-dependent growth-inhibitory effect in all the cell lines. No substantial arrests in the progression of the cells through the cell cycle were observed after treatment of HuH-6 or HA22T/VGH for 48 h with the various inhibitors. On the other hand, there were significant increases …
The influence of atorvastatin on parameters of inflammation left ventricular function, hospitalizations and mortality in patients with dilated cardio…
2013
Background: We assessed the influence of atorvastatin on selected indicators of an inflammatory condition, left ventricular function, hospitalizations and mortality in patients with dilated cardiomyopathy (DCM). Methods. We included 68 DCM patients with left ventricular ejection fraction (LVEF) ≤40% treated optimally in a prospective, randomized study. They were observed for 5 years. Patients were divided into two groups: patients who were commenced on atorvastatin 40 mg daily for two months followed by an individually matched dose of 10 or 20 mg/day (group A), and patients who were treated according to current recommendations without statin therapy (group B). Results: After 5-year follow-u…