Effects of indomethacin on energy metabolism in rat and human jejunal tissue in vitro

2001 ◽  
Vol 101 (5) ◽  
pp. 493-498 ◽  
Author(s):  
Molly JACOB ◽  
Ingvar BJARNASON ◽  
Robert J. SIMPSON
Keyword(s):  
Energy Metabolism ◽  
Oxygen Uptake ◽  
Energy Charge ◽  
Lactate Production ◽  
Inhibitory Effect ◽  
Mitochondrial Morphology ◽  
Rat Jejunum ◽  
Drug Concentrations ◽  
Inflammatory Drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are known to cause enteropathy, but the mechanism by which this toxicity occurs is less well established. This paper sets out to test the hypothesis that these drugs affect oxidative phosphorylation in jejunal tissue, thereby interfering with energy metabolism and rendering the tissue vulnerable to damage. Jejunal tissue obtained from rats and humans was used for in vitro determinations of oxygen uptake, lactate production and energy charge levels in the presence of indomethacin, a commonly used NSAID. In the rat jejunal tissue, drug concentrations of 0.5mM and 2.5mM produced significant decreases in oxygen uptake (P < 0.01) and energy charge levels in the tissue (P < 0.05). There was a corresponding increase in lactate production by the tissue at these indomethacin concentrations (P < 0.05). Rat jejunum examined by electron microscopy after incubation with various concentrations of indomethacin showed ultrastructural effects of the drug on mitochondrial morphology. In human tissue, an inhibitory effect of indomethacin on oxygen uptake was seen, but the effects on lactate production and energy charge were less conclusive. These findings suggest that indomethacin affects mitochondria and thereby impairs energy metabolism in jejunal tissue.

scholarly journals Retinoids irreversibly inhibit in vitro growth of Epstein-Barr virus- immortalized B lymphocytes

Blood ◽  
1996 ◽  
Vol 88 (8) ◽  
pp. 3147-3159 ◽  
Author(s):  
F Pomponi ◽  
R Cariati ◽  
P Zancai ◽  
P De Paoli ◽  
S Rizzo ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Epstein Barr Virus ◽  
Antigen Expression ◽  
Inhibitory Effect ◽  
Lymphoproliferative Disorders ◽  
Nuclear Antigen ◽  
Barr Virus ◽  
Drug Concentrations ◽  
Epstein Barr

Natural and synthetic retinoids have proved to be effective in the treatment and prevention of various human cancers. In the present study, we investigated the effect of retinoids on Epstein-Barr virus (EBV)-infected lymphoblastoid cell lines (LCLs), since these cells closely resemble those that give rise to EBV-related lymphoproliferative disorders in the immunosuppressed host. All six compounds tested inhibited LCL proliferation with no significant direct cytotoxicity, but 9-cis-retinoic acid (RA), 13-cis-RA, and all-trans-RA (ATRA) were markedly more efficacious than Ro40–8757, Ro13–6298, and etretinate. The antiproliferative action of the three most effective compounds was confirmed in a large panel of LCLs, thus appearing as a generalized phenomenon in these cells. LCL growth was irreversibly inhibited even after 2 days of treatment at drug concentrations corresponding to therapeutically achievable plasma levels. Retinoid-treated cells showed a marked downregulation of CD71 and a decreased S-phase compartment with a parallel accumulation in Gzero/ G1 phases. These cell cycle perturbations were associated with the upregulation of p27 Kip1, a nuclear protein that controls entrance and progression through the cell cycle by inhibiting several cyclin/cyclin-dependent kinase complexes. Unlike what is observed in other systems, the antiproliferative effect exerted by retinoids on LCLs was not due to the acquisition of a terminally differentiated status. In fact, retinoid-induced modifications of cell morphology, phenotype (downregulation of CD19, HLA-DR, and s-Ig, and increased expression of CD38 and c-Ig), and IgM production were late events, highly heterogeneous, and often slightly relevant, being therefore only partially indicative of a drug-related differentiative process. Moreover, EBV-encoded EBV nuclear antigen-2 and latent membrane protein-1 proteins were inconstantly downregulated by retinoids, indicating that their growth-inhibitory effect is not mediated by a direct modulation of viral latent antigen expression. The strong antiproliferative activity exerted by retinoids in our experimental model indicates that these compounds may represent a useful tool in the medical management of EBV-related lymphoproliferative disorders of immunosuppressed patients.

Effects of indomethacin on energy metabolism in rat jejunal tissue in vivo

2002 ◽  
Vol 102 (5) ◽  
pp. 541-546 ◽  
Author(s):  
Molly JACOB ◽  
Ingvar BJARNASON ◽  
Robert J. SIMPSON
Keyword(s):  
Energy Metabolism ◽  
Oxygen Uptake ◽  
Mitochondrial Function ◽  
Clinical Medicine ◽  
Ex Vivo ◽  
Energy Charge ◽  
Early Event ◽  
Sprague Dawley ◽  
Lactate Levels

The non-steroidal anti-inflammatory drugs (NSAIDs) are a widely used group of drugs in clinical medicine. However, their propensity to cause gastrointestinal damage limits their clinical utility. The pathogenesis of this toxicity is not well established. It has been postulated that an early event in the development of damage is an effect of these drugs on mitochondrial function. The present paper sets out to evaluate the effects of indomethacin, a commonly used NSAID, on energy metabolism in vivo. Indomethacin was administered to male Sprague-Dawley rats, either intrajejunally or orally, and indices of mitochondrial function were determined. The parameters chosen for this purpose were oxygen uptake by, lactate levels in and the energy charge of jejunal tissue. Oxygen uptake by and energy charge in jejunal tissue were unaffected at 1 and 3h after dosing by gavage with indomethacin. The drug significantly affected the tissue lactate/pyruvate ratio at 3h (but not at 1h) after oral dosing. Effects of indomethacin on jejunum incubated ex vivo were found to be reversible. The data suggest that indomethacin affects mitochondrial function in vivo, but that compensatory changes in glycolytic rate maintain energy charge.

scholarly journals Signal-transduction protein PII from Synechococcus elongatus PCC 7942 senses low adenylate energy charge in vitro

2011 ◽  
Vol 440 (1) ◽  
pp. 147-156 ◽  
Author(s):  
Oleksandra Fokina ◽  
Christina Herrmann ◽  
Karl Forchhammer
Keyword(s):  
Signal Transduction ◽  
Energy Charge ◽  
Inhibitory Effect ◽  
Synechococcus Elongatus ◽  
Adenylate Energy Charge ◽  
Signal Transduction Protein ◽  
Signal Transduction Proteins ◽  
Synechococcus Elongatus Pcc 7942 ◽  
And Control

PII proteins belong to a family of highly conserved signal-transduction proteins that occurs widely in bacteria, archaea and plants. They respond to the central metabolites ATP, ADP and 2-OG (2-oxoglutarate), and control enzymes, transcription factors and transport proteins involved in nitrogen metabolism. In the present study, we examined the effect of ADP on in vitro PII-signalling properties for the cyanobacterium Synechococcus elongatus, a model for oxygenic phototrophic organisms. Different ADP/ATP ratios strongly affected the properties of PII signalling. Increasing ADP antagonized the binding of 2-OG and directly affected the interactions of PII with its target proteins. The resulting PII-signalling properties indicate that, in mixtures of ADP and ATP, PII trimers are occupied by mixtures of adenylate nucleotides. Binding and kinetic activation of NAGK (N-acetyl-L-glutamate kinase), the controlling enzyme of arginine biosynthesis, by PII was weakened by ADP, but relief from arginine inhibition remained unaffected. On the other hand, ADP enhanced the binding of PII to PipX, a co-activator of the transcription factor NtcA and, furthermore, antagonized the inhibitory effect of 2-OG on PII–PipX interaction. These results indicate that S. elongatus PII directly senses the adenylate energy charge, resulting in target-dependent differential modification of the PII-signalling properties.

Severe nose bleeding after intake of acetylsalicylic acid: von Willebrand disease type 2A

2003 ◽  
Vol 23 (03) ◽  
pp. 135-137
Author(s):  
B. Mansouri Taleghani ◽  
W. A. Wuillemin ◽  
N. X. von der Weid
Keyword(s):  
Acetylsalicylic Acid ◽  
Laboratory Diagnosis ◽  
Inhibitory Effect ◽  
Von Willebrand Disease ◽  
Bleeding Disorders ◽  
Laboratory Findings ◽  
History Of ◽  
Inflammatory Drugs ◽  
Von Willebrand

SummaryThis case report of a school boy with a history of severe and repeated episodes of epistaxis presents a short overview of the clinical and laboratory findings which lead to confirm the suspected diagnosis of von Willebrand disease (vWD). Suspicion of defective primary haemostasis should arise when unusual (because of their number or duration) mucosal bleeds appear in an otherwise normal and healthy patient. Because of its definitive inhibitory effect on platelet aggregation, acetylsalicylic acid (more than other non-steroidal anti-inflammatory drugs exerting unselective inhibition of cyclooxygenase) is a strong factor in triggering or sustaining the bleeding disorders in these patients. Among the congenital disorder of primary haemostasis, vWD is by far the most frequent one.The difficulties of laboratory diagnosis of vWD are stressed; the promises and pitfalls of new in vitro methods for measuring primary haemostasis (PFA-100® analyzer) are discussed. An accurate diagnosis of the specific type of vWD is of critical importance for correct patient management as well as for genetic counseling.

EFFECTS OF DIHYDROSTREPTOMYCIN ON AMINO ACID INCORPORATION INTO THE PROTEINS OF M. TUBERCULOSIS (BCG)

1959 ◽  
Vol 37 (1) ◽  
pp. 687-697
Author(s):  
E. Stachiewicz ◽  
J. H. Quastel
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Sodium Stearate ◽  
Ehrlich Ascites Carcinoma ◽  
Inhibitory Effect ◽  
Total Radioactivity ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Drug Concentrations

A study has been made of the effects of dihydrostreptomycin on amino acid incorporation into the proteins of M. tuberculosis (BCG). Suspensions of this organism on incubation at 37° with glycine-1-C14give rise, aerobically, to labelled proteins in which 80% of the radioactivity appears in the glycine and serine moieties of the proteins and about 20% in alanine and aspartic acid. In presence of glycine-2-C14, radioactivity appears in a larger number of amino acids of the protein. Incubation with serine-3-C14leads to a distribution of radioactivity in the amino acids in BCG proteins but alanine-1-C14and valine-1-C14give rise to proteins with the radioactivity almost entirely in the corresponding amino acids. The process of aerobic incorporation of radioactivity from glycine-1-C14in BCG proteins is stimulated by the presence of glucose, glycerol, sodium pyruvate, sodium stearate, or sodium benzoate in the medium in which the cells are incubated, the rate of incorporation being approximately constant over a period of 4 hours. The incorporation depends largely on the presence of oxygen. Dihydrostreptomycin (33 μg per ml) markedly inhibits labelling of proteins in the cell suspensions in presence of radioactive amino acids, the inhibition increasing with concentration of the streptomycin to an optimal concentration of 200 μg/ml. Penicillin and isonicotinic hydrazide are inactive but chloromycetin is an effective inhibitor. Cyanide, arsenite, and azide are inhibitory. The presence of lecithin stimulates incorporation of radioactivity from glycine-1-C14into BCG proteins. Dihydrostreptomycin inhibitions of amino acid incorporation into BCG proteins increase with time of incubation of the cells with the drug. Concentrations of dihydrostreptomycin that inhibit labelled amino acid incorporation into labelled proteins by 50% have no effect on BCG respiration. The drug has no inhibitory effect on labelled amino acid incorporation in E. coli or Ehrlich ascites carcinoma cells in vitro but is effective with M. phlei. It does not affect selectively the distribution of radioactivities of the component amino acids of BCG proteins; only the total radioactivity incorporated into the proteins is diminished. The results lead to the conclusion that dihydrostreptomycin brings about an inhibition of protein synthesis in the BCG strain of M. tuberculosis at concentrations at which it exerts antibiotic effects.

Inhibition of bovine adrenocortical steroidogenesis by benzodiazepines: a direct effect on microsomal hydroxylation or an inhibition of calcium uptake?

1992 ◽  
Vol 135 (2) ◽  
pp. 361-369 ◽  
Author(s):  
I. Thomson ◽  
R. Fraser ◽  
C. J. Kenyon
Keyword(s):  
Direct Effect ◽  
Calcium Metabolism ◽  
Competitive Inhibitor ◽  
Inhibitory Effect ◽  
Zona Glomerulosa ◽  
Free Calcium ◽  
Steroid Hydroxylase ◽  
Drug Concentrations ◽  
Ca Uptake

ABSTRACT We have previously reported that benzodiazepines inhibit microsomal steroid hydroxylases. We have now studied their effects at much lower drug concentrations and have also addressed the suggestion that benzodiazepines alter cellular calcium metabolism. We investigated the in-vitro effects of midazolam on microsomal steroid hydroxylation by measuring basal and ACTH-stimulated cortisol and 17α-hydroxyprogesterone (17-OHP) synthesis. Threshold inhibition of basal cortisol production was achieved by 3·4 μmol midazolam/1 while ACTH-stimulated production required 13·6 μmol/l. This was accompanied by a biphasic response of 17-OHP production, rising to a maximum at 13·6 μmol midazolam/l for basal and 6·8 μmol midazolam/l for ACTH-stimulated synthesis suggesting a preferential inhibitory effect on 21-hydroxylase activity at < 6·8 μmol/l and additonal effects on 17α-hydroxylation at higher drug concentrations. This explains the inhibition of ACTH-stimulated cortisol synthesis by midazolam (50% inhibitor dose (IC50) 22 μmol/l). Using 21-deoxycortisol as substrate, we have demonstrated that midazolam is a competitive inhibitor of 21-hydroxylase (inhibitory constant (KI) 35 μmol/l). Both midazolam and diazepam inhibited K+-stimulated aldosterone synthesis, with IC50 values of 1·2 μmol/l and 0·8 μmol/l respectively, which are far lower than those observed for ACTH-stimulated cortisol synthesis. With 11β-hydroxyprogesterone as substrate, the KI for the inhibition of aldosterone synthesis by midazolam was 54 μmol/l. Potassium stimulates aldosterone biosynthesis at least partly by changing intracellular free calcium levels. To investigate possible antagonistic effects of benzodiazepines on calcium metabolism, we measured 45Ca uptake in the presence of midazolam. Both basal (P < 0·01) and K+-stimulated 45Ca uptake (P < 0·05) were inhibited by the drug although the effects of K+ were not completely abolished. Comparison of the dose-dependent effects of midazolam on basal 45Ca uptake in cell suspensions prepared from different areas of the adrenal cortex indicated that zona glomerulosa cells are more sensitive to midazolam. We confirm that benzodiazepines at low concentrations have a direct effect on microsomal steroid hydroxylase enzymes in vitro and postulate that the greater sensitivity to benzodiazepines of K+-stimulated aldosterone synthesis, when compared with either ACTH-stimulated cortisol synthesis or conversion of 21-deoxycortisol to cortisol, may be explained by additional effects of these drugs on plasma membrane calcium transport. Journal of Endocrinology (1992) 135, 361–369

Oxytetracycline inhibition of mitochondrial protein synthesis in bovine lymphocytes infected withTheileria parvaor stimulated by mitogen

Parasitology ◽  
1990 ◽  
Vol 101 (3) ◽  
pp. 387-393 ◽  
Author(s):  
P. R. Spooner
Keyword(s):  
Protein Synthesis ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Oxidase Activity ◽  
Mitochondrial Protein ◽  
Inhibitory Effect ◽  
Mitochondrial Protein Synthesis ◽  
Drug Concentrations ◽  
Bovine Lymphocytes

SUMMARYOxytetracycline (OTC) significantly inhibited cytochrome c oxidase activity in bovine lymphocytes infected withTheileria parvaand in uninfected mitogen-stimulated lymphocytes. The inhibitory effect was detectedin vitrowithin 24 h of treatment with drug concentrations as low as 1 µg/ml. Following mitogen stimulation of lymphocytes, concentrations of 3 and 10 µg/ml OTC completely inhibited an increase in cytochrome c oxidase activity for 48–72 h. This inhibitory activity was considered to be due to a direct effect on lymphoblast mitochondrial protein synthesis. As a consequence, adenosine triphosphate activity was significantly reduced in lymphocytes stimulated either by infection withT. parvasporozoites or by mitogen and then treated with OTC. The results also indicated that parasite mitochondrial protein synthesis was inhibited by OTC. The activity of OTC reported in this study could explain the suppression of disease following ‘infection and treatment’ immunization against East Coast fever and thein vitrodrug-inhibition of schizont development.

The Effect of Glucosone on the Proliferation and Energy Metabolism of in vitro Grown Ehrlich Ascites Tumor Cells

1981 ◽  
Vol 36 (3-4) ◽  
pp. 255-261
Keyword(s):  
Cell Proliferation ◽  
Energy Metabolism ◽  
Tumor Cells ◽  
Lactate Production ◽  
Competitive Inhibitor ◽  
Ehrlich Ascites Tumor ◽  
Ascites Tumor ◽  
Hexokinase Activity ◽  
Ehrlich Ascites

1) Proliferation and energy metabolism of in vitro grown Ehrlich ascites tumor (EAT) cells in the presence of glucosone, (ᴅ-arabino-3.4.5.6-tetrahydroxy-2-oxo-hexanal) a competitive inhibitor of hexokinase, were studied. 2) Proliferation of the cells was completely inhibited by 2 mᴍ glucosone without severely affecting viability (dye exclusion test). No phase specific arrest of cell growth was observed. 3) Incorporation of [14C]thymidine into an acid insoluble fraction of the cells decreases to 5% of the controls within 8 -10 h . Incorporation of [14C]leucine begins to slow down immediately after treatment with glucosone. 4) The inhibitor (2 mᴍ) reduces the lactate production of the cells by 60%, respiration by about 20%; the ATP/ADP ratio slows down from 4.75 to 3.5. 5) The total inhibition of cell proliferation by 2 mᴍ glucosone cannot be explained exclusively by inhibition of hexokinase activity and impairment of energy metabolism. Because of a lack of specificity, glucosone is not a suitable inhibitor for studies on the relationship between hexokinase activity and cell proliferation of tumor cells

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