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Biomedical subjects

J Durand

Publications and source records attributed to J Durand.

At least 127 records · Page 7Linked to original sources
PubMed1981

[Inhibition of the lymphocyte response by metabolites released by the lipoxygenase of mouse macrophages].

Arachidonic acid can be transformed into a series of metabolites by the lipoxygenase enzyme activity of Mouse peritoneal macrophages. The resulting metabolites inhibit tritiated thymidine uptake by Mouse splenocytes stimulated by ConA or PHA. They suppress the development of killer cells. When mice are injected with 15-hydroperoxide, their splenocytes show a decreased H3-thymidine uptake after lectin stimulation.

Animals↗
PubMed1981

Quantitative profiling of the metabolic cascade of arachidonic acid by capillary gas chromatography mass spectrometry.

The analytical approach described allows for the rapid screening and concurrent quantitative determination of all of the major metabolites of the cyclooxygenase pathway of arachidonic acid, including the primary prostaglandins PGE2, PGD2 and PGF2 alpha in addition to the stable end-products of short-lived prostacyclin and thromboxane A2 (6-keto-PGF1 alpha and TXB2, respectively), generated by incubating arachidonic acid with mouse peritoneal macrophage cells. After derivatization into the corresponding methyl ester-methoxime-TMS derivative, the extracted endogenous compounds were analysed by combined high efficiency glass capillary column chromatography and selected ion monitoring. Comparatively lower detection limits can be achieved with the methyl ester-butylboronate-TMS derivatives (e.g. 10 pg for 6-keto-PGF1 alpha). A brief account is also presented on a new type of mixed methyl ester-pentafluorobenzyloxime-butylboronate-TMS derivative of TXB2 and 5-keto-PGF1 alpha.

Animals↗
PubMed1981

Volume flow, hydraulic conductivity and electrical properties across bovine tracheal epithelium in vitro: effect of histamine.

Volume flow (Jv), potential difference (delta psi), short-circuit current (io) and electrical resistance (R) were measured simultaneously across bovine tracheal epithelium in vitro. Under basal conditions, with no applied hydrostatic or osmotic pressure gradients (delta P = 0, delta phi = 0), no spontaneous Jv was observed. delta psi was 31 +/- 2 mV (lumen negative ), io 161 +/- 8 microA cm-2 and R 202 +/- 9 omega cm2, n = 50. When a delta pi was applied, by adding 20 - 80 mM sucrose into the medium bathing either the luminal or the serosal side of the tissue, a linear relationship was found between delta pi and Jv toward the lumen or toward the serosa. The apparent hydraulic conductivity (apparent Lp) was 4.6 - 4.9 10(-6) cms-1 atm-1. Histamine 10(-4) M did not induce any spontaneous Jv under basal conditions and had no effect on io nor on R. However, histamine caused a 100% increase in Jv elicited by sucrose gradients. It was concluded that histamine exerts a selective action on the hydraulic conductivity of bovine tracheal epithelium. Experiments using H1-receptors antagonists (diphenhydramine, dimetindene, chloropyramine) and H2-antagonists (cimetidine, metiamide) or a H2-agonist (impromidine) showed that the increase of Lp induced by histamine was mediated via H2-receptors.

Animals↗
PubMed1981

Release of platelet-activating factor (PAF-acether) and arachidonic acid metabolites from alveolar macrophages.

Human, monkey and rat alveolar macrophages (AM) release PAF-acether in a dose-dependent fashion in the presence of 1 to 5 microgram/ml ionophore A 23187 (2.5 pmol of PAF-acether from 2.5 x 10(5) cells) but not in the presence of zymosan. Arachidonic acid (AA) metabolites released from AM from these species were studied. Thromboxane A2 TxA2) - detected by its action on rabbit arteries - was released from human, monkey and rat AM upon addition of 0.5 mM AA. This release was inhibited by aspirin and indomethacin. Lipoxygenase and cyclooxygenase AA metabolites from rat AM were identified using high efficiency glass capillary column gas chromatography coupled to mass spectrometry. The cyclooxygenase metabolites PGF2 alpha, E2 and D2 and TxB2 were identified. The lipoxygenase-dependent AA metabolites were explored using aspirin-pretreated AM. Only 12 HETE was found. These data indicate that AM secrete several substances with bronchoconstrictive activity: PGF2 alpha, D2, TxA2 and PAF-acether. Therefore an active role of AM in human and experimental bronchoconstriction must be considered.

Animals↗
PubMed1981

Metabolism of polyunsaturated fatty acids by mouse peritoneal macrophages: the lipoxygenase metabolic pathway.

When resident macrophages from mice are incubated with exogenous polyunsaturated fatty acids, they produce lipoxygenic metabolites. To delineate this metabolic chart we used high pressure liquid chromatography and gas chromatography prior to mass spectrometry-computer system. The lipoxygenic activity of these cells leads to many compounds. Among them we describe the monohydroxylated metabolites and vicinal hydroxyepoxyenes. In the mechanism of formation of the latter unstable cyclic precursors might occur as intermediates between hydroperoxides and them. Dihydroxy compounds could arise from hydrolysis of unstable epoxide precursor which could be the second substrate of the glutathione transferase system and could lead to thioaminolipids.

Animals↗
PubMed1981

Transformation of arachidonic acid into monohydroxy-eicosatetraenoic acids by mouse peritoneal macrophages.

Mouse peritoneal macrophages synthesize 6 monohydroxylated eicosatetraenoic acids when incubated with exogenous arachidonic acid. These compounds were identified by chromatographic techniques (high pressure liquid chromatography and high efficiency glass capillary column gas chromatography and mass spectrometry. The chromatographic and spectrometric data are presented. These results show that peritoneal macrophages constitute one of the best systems to study in evaluating the metabolism of oxygenated products of arachidonic acid.

Animals↗
PubMed1981

Time course of plasma growth hormone during exercise in humans at altitude.

The effects of hypoxia on growth hormone release during submaximal exercise were studied 1) in eight highlanders (HL) at 3,800 m (La Paz, Bolivia); and 2) in five lowlanders (LL) at sea level, after 5 days' sojourn at 2,850 m, and while breathing a hypoxic gas mixture (FIO2 - 0.15 corresponding to PIO2 at 2,850 m) 1 mo after returning to sea level. Concentrations of immunoreactive human growth hormone ([IRHGH]), blood glucose ([G]), free fatty acids ([FFA]), and lactate ([LA]) were determined repeatedly at rest, during 1 h of exercise, and after 1 h of recovery. Compared with LL, in HL, the resting value of [IRHGH] is higher, the rate of increase at the beginning of exercise is faster and earlier, but the mean maximal value reached at the end of exercise is similar. The response pattern in LL during the early stages of exposure to hypoxia resembles that of HL. No correlation was found between peak values of [IRHGH] and maximal values of [LA] and [FFA] or minimal values of [G]. The possible causes of the different time sequence observed in growth hormone dynamics during hypoxia are suggested: an alteration of the clearance of the hormone through a more pronounced reduction of hepatic blood flow or a difference in the state of the pituitary gland before the exercise begins. The study emphasizes the importance of characterizing time sequence of [IRHGH] by parameters other than the maximal value, e.g., by mean concentration computed over exercise period.

Acclimatization↗
PubMed1980

Prostacyclin production by cultured smooth muscle cells from atherosclerotic rabbit aorta.

Prostacyclin (PGI2) synthesis seems to be one of the major physiological mechanisms involved in regulating platelet and vessel wall interactions. PGI2 is produced in large amounts by vascular endothelial cells, and vascular smooth muscle cells (SMC) also produce significant quantities. The capacity of SMC to produce PGI2, especially after endothelial injury, seems to be of importance. It is probably this type of situaton that is involved in the atherosclerotic process: experimental atherosclerosis in rabbits has been associated with a severe decrease in PGI, synthesis by arteries. Lipid peroxide accumulation within the arterial wall or in the plasma may also be involved in this process. Using arterial SMC in culture, we demonstrate here that, in comparison with healthy cultured cells, cells originating from atherosclerotic aorta have a decreased capacity to produce PGI2. The results were obtained using biological and radiochemical techniques and were confirmed by GC-MS. They suggest a potential role for PGI2 in inhibiting the atherosclerotic process.

Animals↗
PubMed1980

Penile erection following complete spinal cord injury in man.

Three types of erection following complete spinal transection (at lower thoracic or thoracolumbar levels) in man are described. Reflex erection involves both corpus cavernosum and corpus spongiosum if the lower level of cord injury or lesional sector (LLLS) is cranial to T10/12, and involves only corpus cavernosum if the LLLS is caudal to T12/L2. Psychogenic erection may occur when the upper level of cord injury or lesional sector (ULLS) is caudal to T12 and when testicular sensation is normal. A mixed erection can occur when the ULLS is caudal to T10/12 and the LLLS cranial to S2.

Adolescent↗
PubMed1980

Ribosomal vaccines: preparation of subcellular fractions.

Methods for isolation and analysis of subcellular bacterial fractions intended to be used in the preparation of ribosomal vaccines are described. Cultivation conditions in fermentors for obtaining maximal growth curve slopes are studied; cultivation is stopped before the end of the exponential growth phase in order to collect biomasses having a high viability rate, which is essential for the quality of the subcellular fractions isolated thereafter. Extraction methods for ribosomes and ribosomal RNA, as well as two proceedings for preparing adjuvant proteoglycans from Klebsiella pneumoniae membranes, are described. The analytical methods used for the control of these preparations and the results obtained for the various fractions are given.

Bacteria↗
PubMed1979

Transfomration of arachidonic acid into 12-hydroxy-5,8,10,14-eicosatetraenoic acid by mouse peritoneal macrophages.

Mouse peritoneal macrophages were incubated at 37 degrees C for 30 min with arachidonic acid (all-cis-5,8,11,14-eicosatetraenoic acid). Oxygenation of arachidonic acid in mouse peritoneal macrophages occurs by two major pathways: fatty acid cyclooxygenase and lipoxygenase. The major metabolite of the latter is 12-hydroxy-5,8,10,14-eicosatetraenoic acid which was identified by gas liquid chromatography on high resolution glass capillary column and mass spectrometry.

Animals↗