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Biomedical subjects

P Kourounakis

Publications and source records attributed to P Kourounakis.

At least 19 recordsLinked to original sources
PubMed1991

Anti-inflammatory and immunomodulating effects of the novel agent gamma-(2-aminoethylamino)-2-butyrothienone. 1st communication: inhibitory effects on mouse paw edema.

A series of 4-hydroxy-(or-amino)-ethyl-amino butyrophenones or butyrothienones were synthesized. For detail studies on antiinflammatory effects, gamma-(2-aminoethylamino)-2-butyrothienone (gamma-ABT) was chosen as representative of these new non-steroidal anti-inflammatories (NSAID). The effect on mouse paw edema induced by various phlogistic agents was first investigated. The inhibitory effect of gamma-ABT on carrageenin-induced edema was remarkable and nearly equal to that of indometacin. Similarly to indometacin, gamma-ABT inhibited the early and late stage of yeast-induced edema in contrast to concanavalin A (Con A) induced edema which was only inhibited by gamma-ABT. Both the above induced edema are supposed to be unrelated to prostaglandins in the rat system. gamma-ABT displayed an inhibitory effect on nystatin-induced edema similar to indometacin suggesting that gamma-ABT has significant membrane stabilizing action and a strong blocking action on synthesis of prostaglandins. gamma-ABT inhibited as well the sustained edema induced by mustard. In conclusion gamma-ABT is an effective agent not only on acute but also on subacute and chronic inflammation and its mode of action appears similar to other NSAID. gamma-ABT posses in addition the advantage of antioxidant activity which is not shared by selective cyclooxygenase inhibitors and thus should be potentially effective in autoimmune diseases.

Animals↗
PubMed1991

Anti-inflammatory and immunomodulating effects of the novel agent gamma-(2-aminoethylamino)-2-butyrothienone. 2nd communication: inhibitory effect on rat adjuvant induced disease.

The effect of the novel agent gamma-(2-aminoethylamino)-2-butyrothienone (gamma-ABT) on local and systemic changes of rats with adjuvant induced disease (AID) was investigated, gamma-ABT showed potent inhibitory effect on adjuvant primary inflammation and almost totally inhibited the secondary lesions. gamma-ABT improved the changes in lymphoid organ weight except of the thymus. gamma-ABT improved the change in albumin/globulin ratio, which is a parameter of systemic inflammatory reaction but did not improve the body weight gain in AID and normal rats. In addition gamma-ABT did not affect directly T or B lymphocytes as shown by the lymphocyte responses to mitogen (Con A) and a T cell dependent antigen (SRBC) but rather inhibited the suppressor cells found in AID. Although structurally gamma-ABT is completely different from known non-steroidal anti-inflammatories, immunosuppressive drugs behave to a great extent like them.

Adjuvants, Immunologic↗
PubMed1990

Antioxidant activity of and interleukin production affected by honey bee venom.

Honey bee venom is found to inhibit significantly nonenzymatic lipid peroxidation. It also possesses a considerable hydroxyl radical scavenging activity, evaluated by its competition with dimethyl sulfoxide for HO.. These results, in relation to the in vitro suppression mainly of interleukin-1 production offered by honey bee venom, may further support that antioxidant activity is involved in the anti-inflammatory activity of honey bee venom.

Animals↗
PubMed1989

Immunosuppression by a novel analgesic-opioid agonist.

The effect of a new, centrally acting analgesic, 2-n-pentyloxy-2-phenyl-4- methyl-morpholine (PM) on the humoral antibody isotype responses, mitogenic responses, and interleukin production and assay was studied. Treatment with this opioid agonist exerted a suppressive effect on the antibody responses to TD [sheep red blood cells (SRBC), fluoresceinated human gamma globulin (HGG-FITC)] and TI [fluoresceinated dextran (DEX-FITC), lipopolysaccharide (LPS)]antigens in mice. The suppression was found to be dose- and time-dependent for all antigens tested, suggesting that PM affected both T and B cells. PM impaired lymphocyte functions, as the in vitro T and B mitogen reactions were inhibited in a dose- and time-dependent manner in mice and rats. PM, even at the highest concentration used, could not completely inhibit the production of interleukin 1 (IL-1)-like activity, but it caused complete inhibition, in a dose-dependent manner, of the production of IL-2-like activity. In addition, PM inhibited the assays of both IL-1 and IL-2. Naloxone counteracted all immunosuppressive effects of PM in vivo and in vitro. From this it was concluded that PM operates on the immune system directly, via opioid receptor mechanisms. Our data suggest that immunosuppression by PM, an opioid agonist, may be exerted by an inhibition of interleukin action on lymphocytes, and they confirm the important role of opiate receptors in lymphocyte function.

Animals↗
PubMed1987

Effect of age on the induction of in vitro drug metabolism by pregnenolone-16 alpha-carbonitrile (PCN); effect of age and PCN on immune responses.

The drug metabolizing capacity and the immune responses of normal and PCN treated young, adult and old rats were studied. In normal young and old rats the drug metabolism in general and the immune responses were reduced in comparison to adult animals. PCN treatment caused significant increase of drug metabolism in all age groups of animals due to induction of the microsomal enzymes of the liver. However, there were certain drug dependant variations in the different age groups of rats. PCN given in vivo affected differently the responses of T and B-cells in the young, adult and old animals. PCN is a non-hormonal microsomal enzyme inducer and the question a-rises as to whether there is any connection between this process and the immune system.

Aging↗
PubMed1987

In vivo interaction of spironolactone and phenobarbital with cholesterol; effect on cholesterol organ concentration.

In this work, the effect of pretreatment with spironolactone or phenobarbital on female Wistar rats after a chronic administration of cholesterol, upon the cholesterol concentration in blood, brain and liver was examined. It was found that the pretreatment reduced cholesterol in all tissues in the order, brain - plasma - liver. The findings were attributed to an increased biodegradation and disposition of cholesterol. It could also be concluded that after the pretreatment we may have a predominance of the catabolic and/or the disposition rather than of the synthetic and/or absorption processes for the steroid.

Animals↗
PubMed1982

Effect of pregnenolone-16 alpha-carbonitrile on the biliary and urinary excretion of imipramine and some of its metabolites in rats.

The influence of pregnenolone-16 alpha-carbonitrile (PCN) upon the biliary and urinary excretion of unchanged imipramine and some of its metabolites was investigated in female rats. The substrate and its metabolites were identified and quantified by thin-layer chromatography and/or gas-liquid chromatography. PCN augmented urinary excretion of desipramine and the imipramine- and desipramine-glucuronides. PCN pretreatment also diminished the urinary elimination of imipramine N-oxide whereas proadifen hydrochloride had an inverse effect, suggesting a shift in the metabolic pathways of imipramine. The biliary excretion of the imipramine and desipramine glucuronides was not significantly altered by PCN.

Animals↗
PubMed1980

Liver ultrastructure during acute stress.

An ultrastructural, morphologic and histochemical study was made on the livers of rats exposed to eight different acute stressors: fasting, cortisol injecions, reserpine injections, restraint, spinal cord transection, immersion in hot water, exposure to cold and forced muscular exercise in a revolving drum. After 48 hours of exposure to stress, electron microscopy of the liver revealed rough endoplasmic reticulum fragmentation and dilatation, glycogen depletion, and mitochondrial enlargment. The most striking change, however, was an increase in the number and size of autophagic vacuoles which were limited by single or multiple membranes. A cytochemical study revealed that in the former case, the vacuolar membranes did not show a glucose-6-phosphatase positive reaction, whereas they did in the latter case. The vacuoles contained acid phosphatase positive material as well as organelles in various stages of degradation. Following exposure to most of the stressors, a marked increase of plasma corticosterone was noted, with a lowered rectal temperature and the appearance of the typical stress triad (adrenal hypertrophy, thymicolymphatic involution and gastrointestinal ulcers). The severity of the morphologic changes appeared to parallel the degree of hypothermia caused by the stressor. The results suggest that autophagy in the liver may be an adaptive response to stressors at the subcellular level.

Animals↗
PubMed1980

Inhibition by ethionine and beta-diethylaminoethyl diphenylpropylacetate of RNA and protein synthesis in the rat liver, and its reversal by pregnenolone-16 alpha-carbonitrile.

The effect of pregnenolone-16 alpha-carbonitrile (PCN) on female Sprague-Dawley rats was studied in conjunction with ethionine and beta-diethylaminoethyl diphenylpropylacetate (DADP). The cyanosteroid virtually abolished in inhibitory action of ethionine on orotic acid and leucine uptake by liver microsomes. When PCN was given conjointly with DADP, it completely overshadowed the latter's effect on leucine uptake. DADP was found to act as an inhibitor of the translational mechanism 5 h after its administration, while it exerted a stimulatory influence on the transcriptional mechanism after the same time period.

Animals↗
PubMed1979

Fine structural changes in the liver of young and old rats as influenced by microsomal enzyme inducers.

When given orally to young and old rats, pregnenolone-16 alpha-carbonitrile, spironolactone, or phenobarbital, known microsomal enzyme inducers, caused an increase in smooth endoplasmic reticulum. Dexamethasone, while a potent microsomal enzyme inducer, did not cause smooth endoplasmic reticulum increase. In both untreated and treated old rats, there was dilatation and vesiculation of rough endoplasmic reticulum with occasional granular material present in vesicles. Cytoplasmic lipid droplets of various sizes were frequent. Some mitochondria exhibited polymorphism and a variation in matrical density. Lysosomes and autophagic vacuoles as well as lipid droplets of various sizes were frequent in all groups. These results show that microsomal enzyme inducers influence the subcellular structure of hepatocytes in old rats.

Aging↗
PubMed1979

Effect of steroids and diethylstilbestrol on cocaine toxicity, plasma concentrations and urinary excretion.

Comparative experiments were performed on female rats given pregnenolone-16 alpha-carbonitrile (PCN), spironolactone, triamcinolone, estradiol or diethylstilbestrol to study correlations between the toxic effect of cocaine, its blood clearance and its urinary excretion. PCN and estradiol significantly reduced the toxicity of the drug as well as its plasma levels and urinary excretion. Diethylstilbestrol and spironolactone, unlike triamcinolone, also diminished cocaine toxicity and plasma concentrations.

Animals↗