Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Selenium Compounds”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 577 records · Page 32Linked to original sources
PubMed2004

[The effect of all-trans retinoid acid and sodium selenite (Na2SeO3) on VEGF and its receptor expression in HL-60 cells].

In order to investigate the effect of non-medullar toxicity drug - all trans retinoid acid (ATRA) and cancer preventive trace element-selenium compound - sodium selenite (Na(2)SeO(3)) on the expression of vascular endothelial growth factor (VEGF) and its receptor in HL-60 cells, the expression of VEGF and its receptor in HL-60 cells were detected by ELISA technique and flow cytometry before and after treatment with two drugs. The results showed that the mean VEGF concentrations in the cultural supernatant of 5 and 10 micro mol/L ATRA-treated HL-60 cells for 48 and 72 hours were lower than those of the control group without adding ATRA. The differences between the ATRA-treated groups and the control group were statistically significant (P = 0.001, P = 0.000, P < 0.01, respectively). The levels of VEGF-R on the surface of HL-60 cells also decreased after treatment with ATRA of 5 and 10 micro mol/L for 72 hours, but at 48 hours the expression rates of VEGF-R on HL-60 cells of the two ATRA treated groups were not significantly decreased. At 48 and 72 hours, Na(2)SeO(3) of 5 and 10 micro mol/L had no obvious effect on HL-60 secreting VEGF, but notablely inhibited the expression of VEGF-R. In conclusion, ATRA could inhibit the expression of VEGF and its receptor in HL-60 cell. Na(2)SeO(3) could not inhibit the expression of VEGF in HL-60 cell, but could decrease the receptor expression of VEGF, which mechanism should be further studied. ATRA and Na(2)SeO(3) had not obvious medullar-inhibition, but anti-angiogenesis activity. It is suggested that combination of two drugs with conventional therapy may enhance the effect of radiotherapy and chemotherapy, and reduce the dose and thus toxicity of chemotherapeutic agents.

Dose-Response Relationship, Drug↗
PubMed2004

Selenite-induced p53 Ser-15 phosphorylation and caspase-mediated apoptosis in LNCaP human prostate cancer cells.

The issue of p53 requirement for the caspase-mediated apoptosis induced by selenium in a cancer chemoprevention or chemotherapy context has not been critically addressed. We and others have shown that selenite induces apoptotic DNA laddering in the p53-mutant DU145 prostate cancer cells and the p53-null HL60 leukemia cells without the cleavage of poly(ADP-ribose) polymerase (PARP; i.e., caspase-independent apoptosis), whereas selenium compounds leading to the formation of methylselenol induce caspase-mediated apoptosis in these cells. Because selenite induces DNA single strand breaks, and because certain types of DNA damage activate p53, we investigated whether the human LNCaP prostate cancer cells, which contain a wild-type p53, execute selenite-induced apoptosis through caspase pathways. The results showed that exposure of LNCaP cells for 24 hours to lower micromolar concentrations of selenite led to DNA laddering, and to the cleavage of PARP and several pro-caspases. In contrast to this apoptosis sensitivity, LNCaP cells were rather resistant to similar concentrations of the methylselenol precursor methylseleninic acid. Selenite treatment led to a significant increase in p53 phosphorylation on Ser-15 (Ser15P). Time course experiments showed that p53 Ser15P occurred several hours before caspase activation and PARP cleavage. The general caspase inhibitor zVADfmk completely blocked PARP cleavage, and significantly decreased DNA laddering, but did not affect p53 Ser15P. An inhibitor for caspase-8 was equally as protective as that for caspase-9 against the selenite-induced apoptosis. Attenuating p53 by a chemical inhibitor pifithrin-alpha decreased the selenite-induced p53 Ser15P and led to concordant reductions of PARP cleavage and apoptosis. In summary, selenite-induced p53 Ser15P appeared to be important for activating the caspase-mediated apoptosis involving both the caspase-8 and the caspase-9 pathways in the LNCaP cells.

Amino Acid Chloromethyl Ketones↗
PubMed2004

Selenium is effective in inducing lymphocyte progression through cell cycle in cancer patients: potential mechanisms for its activity.

Epidemiologic evidence in humans suggests a role for selenium in reducing cancer incidence and mortality. The aim of the present study was that to assess the ability of selenium dioxide (SeO2) to enhance the lymphocyte progression through the cell cycle in patients with advanced (stage IV) cancer. Ten patients (mean age 51.9 years, range: 32-74; M/F ratio: 3/7) with tumors at different sites were included in the study. The addition into culture of SeO2 1.5 microM enhanced significantly the progression into S phase of PBMCs isolated from cancer patients, whilst no significant effect was observed on PBMCs isolated from controls. ROS levels were significantly higher, whereas GPx activity was significantly lower in cancer patients than controls. Serum levels of IL-6 and TNFalpha were significantly higher in cancer patients than controls. Our results show the ability of selenium to induce a progression of PBMCs from cancer patients into the cell cycle, which is an essential prerequisite for the physiological functioning of the immune system and thus positively influence the immune status of advanced cancer patients. The mechanism of action of selenium could be to downregulate the production and release of proinflammatory cytokines, which have a role in cancer progression and particularly in the onset of cachexia.

Adult↗
PubMed2004

[Apoptosis and regulation of expressions of apoptosis-related gene Bcl-2 and p53 induced by selenium dioxide in three leukemia cell lines].

OBJECTIVE: To investigate the mechanisms underlying the effect of selenium dioxide (SeO(2)) on the proliferation, apoptosis, and apoptosis-related gene expressions of Bcl-2 and p53 in 3 leukemia cell lines NB4, K562 and HL-60. METHODS: The three leukemia cell lines were treated with 3, 10 and 30 mmol/L SeO(2) and apoptosis detected by flow cytometry and analysis of p53 and Bcl-2 expressions. RESULTS: SeO(2) at 10 and 30 mmol/L could inhibit the proliferation of three leukemia cell lines. SeO(2) treatment at 30 mmol/L for 48 h induced an apoptosis rate of 54.0 %, 46.5 %, 49.6 % in NB4, K562, and HL-60 cells respectively, and down-regulated Bcl-2 expression in NB4 and K562 but not in HL-60 cells. CONCLUSION: SeO(2) can induce apoptosis in NB4, K562 and HL-60 leukemia cells, involving the down-regulation of Bcl-2 and up-regulation of p53.

Antineoplastic Agents↗
PubMed1991

Comparison of the kinetics of a trace and a sublethal dose of selenite in rats, with particular attention being given to blood selenium distribution.

The male rats were injected i.p. with a trace or a sublethal dose of [75Se]selenite (0.01 mg or 1.58 mg/kg Se of body weight, respectively). During seven days following the injection, the whole-body retention, organ distribution and excretion of 75Se were studied, along with 75Se distribution in blood and in blood fractions. Substantial dose-dependent differences in selenite metabolism were found: (i) The rate of 75Se excretion after the injection of the sublethal dose was observed to be substantially higher than with the trace dose - 86% of injected dose (% inj. d.) vs. 41% inj. d. during seven days. In addition to urinary excretion, the exhalation of 75Se took a considerable part in the former case. (ii) The sharp decrease of 75Se levels was a prevalent feature of the 75Se kinetics in most of the studied tissues after the injection of the sublethal dose. On the other hand, after the trace dose injection a considerable decrease of 75Se level was observed only in the liver. In the brain and particularly in the testis the 75Se level increased during seven days after this dose injection. The highest levels of radionuclide were found in liver after both doses. (iii) Over 80% of blood 75Se was contained in blood cells (RBC) at all time intervals studied following the sublethal dose injection. With the trace dose the blood 75Se was present predominantly in plasma. (iv) The distribution of 75Se in protein fractions of blood plasma and RBC-lysate was studied using gel filtration. The albumin fraction was found to be the main acceptor of 75Se in plasma 15 min after both trace and sublethal dose injection. However, in longer time intervals the 75Se distribution pattern in plasma proteins was affected by the dose applied. Most of 75Se present in RBC-lysate (68.5-91.2%) was detected in the haemoglobine fraction at all time intervals after the injection of the sublethal dose. On the other hand, with the trace dose this fraction contained only 7.5-28.5% of 75Se. Incorporation of a significant amount of 75Se to the GSH-Px (glutathione peroxidase) fraction of plasma and RBC-lysate was observed on day seven after the trace dose injection. GSH-Px represented 19% of plasma 75Se and 80% of 75Se present in RBC-lysate. Data on the molecular weight (M(r)) values of plasma and erythrocyte 75Se-GSH-Px were determined on the basis of elution volumes in the course of gel infiltration - 695,000 and 110,000, respectively. The noticeable difference in these values is discussed.

Animals↗
PubMed1989

Biochemical and genetic analysis of Salmonella typhimurium and Escherichia coli mutants defective in specific incorporation of selenium into formate dehydrogenase and tRNAs.

Mutation of a single gene, referred to as selA1 in Salmonella typhimurium and as selD in Escherichia coli, results in the inability of these organisms to insert selenium specifically into the selenopolypeptides of formate dehydrogenase and into the 2-selenouridine residues of tRNAs. The mutation does not involve transport of selenite into the cell or reduction of selenite to selenide since both mutant strains synthesize selenocysteine and selenomethionine from added selenite and incorporate these selenoamino acids non-specifically into numerous proteins of the bacterial cells. Complementation of the mutation in S. typhimurium with the selD gene from E. coli indicates functional identity of the selA1 and selD genes. Although the selA1 gene maps at approximately 21 min on the S. typhimurium chromosome and the selD gene at approximately 38 min on the E. coli chromosome, only a single gene in wild-type S. typhimurium hybridized to the E. coli selD gene probe. Transformation of the mutant Salmonella strain with a plasmid bearing the E. coli selD gene restored formate dehydrogenase activity, 75Se incorporation into formate dehydrogenase seleno-polypeptides and [75Se]seleno-tRNA synthesis. Transformation with an additional plasmid carrying an E. coli formate dehydrogenase selenopolypeptide-lacZ gene fusion showed that the selD gene allowed readthrough of the UGA codon and synthesis of beta-galactosidase in the Salmonella mutant.

Aldehyde Oxidoreductases↗
PubMed1986

Study on the interaction of Se and erythrocyte membrane--protective effect of Se on the erythrocyte membranes.

During the ageing of erythrocyte membrane, the spectrin content, Na,K-ATPase activity as well as the lipid fluidity are obviously decreased. However, supplementation of a trace amount of Na2SeO3 in the medium could prevent the dissociation of spectrin from membrane and delay the changes of Na,K-ATPase activity and lipid fluidity. The effectiveness is proportional to Se concentration within the range of 0.1-1.0 ppm. Similar effect of supplementation of Se on the intact erythrocytes during ageing has been also observed. The protective action of Se on biomembranes is generally interpreted in terms of the activity of Se-containing glutathione peroxidase (GSHPx). However, GSHPx mainly distributes in the cytoplasma of erythrocytes, therefore it seems that the protective action of supplemented Se on the isolated erythrocyte membrane might not be related to the activity of GSHPx.

Erythrocyte Aging↗
PubMed1987

Antagonism between selenium and humic acid.

In this work, two groups of experiments have been done by using mice and luminous bacteria. The results show that there exists an antagonism in toxicity between selenium and humic acid (HA) extracted from the drinking water in Kaschin Beck disease regions. In order to study the chemical mechanism of the antagonism, gel filtration and X-ray photoelectron spectroscopy techniques have been used to study the chemical bonding of the synthetic HA-Se in solution. The relationship between Se and HA in the cause of Kaschin Beck disease is discussed.

Animals↗
PubMed1982

Growth of human hepatoma cells lines with differentiated functions in chemically defined medium.

A human hepatoma cell line, HuH-7, which was established from a hepatocellular carcinoma, was found to replicate continuously in a chemically defined medium when the medium was supplemented with Na2SeO3. The cells grew better in this medium than in serum-containing medium without any adaptation period. Other established human hepatoma and hepatoblastoma cell lines, HuH-6 cl-5, PLC/PRF/5, huH-1, and huH-4, also grew in the defined medium. Although HLEC-1 cells failed to proliferate continuously with Na2SeO3 alone, they grew if a cell-free conditioned medium from HuH-7 cells was added to the medium. These cell lines, except the HLEC-1 cell line, produced the following human plasma proteins among those examined: albumin, prealbumin, alpha 1-antitrypsin, ceruloplasmin, fibrinogen, fibronectin, haptoglobin, hemopexin, beta-lipoprotein, alpha 2-macroglobulin, beta 2-microglobulin, transferrin, lipoprotein, alpha 2-macroglobulin, beta 2-microglobulin, transferrin, Complement Components 3 and 4, and alpha 1-fetoprotein. Beside plasma proteins, the media from HuH-7, HuH-6 cl-5, PLC/PRF/5, and huH-1 contained anti-carcinoembryonic antigen-reactive proteins, and those from PLC/PRF/5, huH-1, and huH-4 medium contained hepatitis B surface antigen. These proteins were detected during periods of serial cultivation over 9 months under the above culture conditions. The hepatoma cell lines grown in the fully defined synthetic medium may provide a new approach for investigating the growth and metabolism of human hepatoma cells in vitro.

Blood↗
PubMed1983

Comparative activation response of splenocytes oxidized by periodic acid and selenium dioxide.

Murine splenocytes were activated by selenium dioxide (SeO2) oxidation of cell membranes, as evidenced by increased tritiated thymidine (3H-TdR) incorporation. In contrast to splenocyte activation by periodic acid (H5IO6), the SeO2-induced response was not inhibited by neuraminidase degradation of cell membranes prior to oxidation, nor by the prior hydroxylamine (NH2OH) addition reaction. However, reduction by borohydride (NaBH4), as a preliminary step to the oxidation by SeO2 and H5IO6, inhibited the subsequent cell activation. Sequential oxidation by H5IO6 and SeO2 increased the cell stimulation index versus the response elicited after one step oxidation by SeO2 or H5IO6. The reverse order of the sequential oxidation depressed the stimulation index relative to oxidation solely by H5IO6, but not by SeO2. It is concluded that the activation of splenocytes by SeO2 is triggered primarily by the conversion of cell membrane carbonyls into corresponding dicarbonyls.

Animals↗
PubMedDate not supplied

Effect of selenium dioxide on the testes of rat.

Selenium dioxide was administered (ip) to albino male rats (200 +/- 5 g) in increasing doses (2, 6 and 10 micrograms/rat, daily) for 90 days. Histologic and histometric study showed that there was dose dependent injury to testes. No cellular deformation was observed following 2 micrograms-dose; whereas 6 micrograms-dose caused significant damage of gametogenic cells. At a dose of 10 micrograms, there was a significant testicular degeneration along with testicular atrophy.

Animals↗
PubMed1982

Selenium and kidney deposits in experimental argyria. Electron microscopy and microanalysis.

The conjugate effects of selenium and silver salts were studied in experimental renal argyria. Microanalysis has led to the localization of products of chemical reactions to Se and Ag in tissue sections. After prolonged treatment with Ag salts alone, there was Ag and S deposits in basal membranes. When Se and Ag were used together, the formation of these deposits in glomerular basal membranes was accelerated spectacularly. Electron probe microanalysis has shown that Se replaces S in silver deposits. Compared to its effect on other metals, Se was shown to have a complex action, characterized primarily by its toxic effect, favoring the appearance of symptoms of argyria.

Animals↗
PubMed1982

Pseudopterygium from exposure to selenium dioxide.

Pseudopterygium and symblepharon developed in a patient exposed to selenium dioxide gas. Previously, a case of pseudopterygium had been reported after exposure to seleniferous acid. This cicatricial condition can be distinguished from the pterygium by eccentric location, the lid scarring, and the absence of pterygium in the other eye. This pseudopterygium recurred despite 11 operations. Full-thickness mucous membrane grafts wee used to separate the lid from the globe.

Adult↗
PubMed1995

Scanning ion microscopy mapping of basement membrane elements and arterioles in the kidney after selenium-silver interaction.

The effects of selenium and silver salts was studied by scanning ionic microscopy during experimental argyria mapping of the different basement membrane elements. The ionic microscope (IMS 4F) was equipped with a high resolution spectrometer giving high spatial resolution on the image obtained. After long-term treatment with silver salt alone, silver and sulphur deposits were observed in the membranes. After administration of selenium and silver salt, it was possible to map nitrogen, sulphur, selenium and silver to the glomerular basement membrane as well as to the wall of the kidney arterioles. In the latter, sulphur, selenium and silver were localized only in the elastic laminae of the walls. This process of precipitation of silver deposits in the membrane can be interpreted as process of selenium "detoxification" of the organism.

Animals↗
PubMed1993

[Inhibition of the protein kinase C-alpha gene overexpression in rat preneoplastic liver by selenium].

Effect of selenium on the protein kinase c-alpha (PKC-alpha) gene expression was observed in the preneoplastic lesions in liver of S.D. rat Solt-Farber model. Overexpression of PKC-alpha was found in preneoplastic liver but not in partially hepatectomized liver. Administration of 4PPm Na2SeO3 in water 2 weeks before i.p injection of DEN (200 ng/kg bw) for 8 weeks reduced the PKC-alpha gene overexpression in preneoplastic liver and the formation of hyperplastic foci, alpha-GT-altered foci and preneoplastic lesions.

Animals↗
PubMed1994

Emerging awareness of the critical roles of S-phosphocysteine and selenophosphate in biological systems.

S-Phosphocysteine residues in proteins are formed as key intermediates in certain enzyme-catalyzed reactions. In phosphoenolpyruvate (PEP)-dependent carbohydrate transport processes, the phosphoryl group of PEP is transferred sequentially to histidine residues of two cytoplasmic proteins, Enzyme I and HPr, common to all of the PEP-dependent carbohydrate transport systems. The phosphoryl group of HPr then is transferred to an essential histidine and an essential cysteine residue located in the cytoplasmic domains of certain substrate-specific, membrane-bound proteins, the actual transporters. Both the N-phosphohistidine and the S-phosphocysteine residues in these Enzyme II domains are transient catalytic intermediates in the final steps that lead to phosphorylation of the bound carbohydrate substrate. In a different type of biological system, numerous proteins involved in signal transduction pathways are phosphorylated on specific tyrosine residues by various kinases and the effects of these modifications are modulated by a family of protein tyrosine phosphate-specific phosphatases. The mechanism of action of these phosphatases involves the transfer of the phosphoryl group from a phosphotyrosine residue in the protein substrate to an essential ionized cysteine residue in the phosphatase polypeptide forming an S-phosphocysteine residue. Reaction of the latter with water and release of orthophosphate complete the phosphatase-catalyzed reaction. Selenophosphate, formed by phosphorylation of a selenol, is a key selenium donor compound in prokaryotes. This extremely oxygen-labile compound is synthesized from ATP and selenide by selenophosphate synthetase. This novel reactive selenium compound is the selenium donor for selenocysteyl-tRNA biosynthesis and for conversion of 2-thiouridine residues in tRNAs to 2-selenouridine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1984

Variation of Se, Zn, Co, Fe and Rb distribution in rats after injection with selenium or sulfur compounds.

Contents of Se, Zn, Co, Fe and Rb in liver, kidney, heart, spleen, brain, pancreas and testicle of Wistar rats were determined 2 h after i.p. injection with selenodiglutathione, selenomethionine, selenocystine, selenocystamine, methionine, cystine and cystamine. Instrumental neutron activation analysis (INAA) was applied as the analytical method. It was found that Se was incorporated to all examined rat organs. High Se incorporation was observed after injection with selenomethionine and selenocystine. Variations in the Zn, Co, Fe and Rb contents were observed in all the investigated organs after the injections. These variations depended upon injected compounds.

Animals↗