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Biomedical subjects

E J Corey

Publications and source records attributed to E J Corey.

At least 163 records · Page 9Linked to original sources
PubMed1983

Local effects of synthetic leukotrienes (LTC4, LTD4, LTE4, and LTB4) in human skin.

The local effects of intracutaneous injections into humans of 1-3 nmol of five products of arachidonic acid metabolism, leukotrienes (LT) C4, D4, E4, and B4 from the 5-lipoxygenase pathways and prostaglandin (PG) D2 from the cyclooxygenase pathway, were assessed clinically and histologically. In equimolar concentrations, LTC4, LTD4, and LTE4, elicited erythema and wheal formation, in which a wheal with central pallor was present up to 2 hr, and the erythema persisted as long as 6 hr. PGD2 elicited a wheal that lasted up to 1 hr and erythema that lasted up to 2 hr. The dermal vascular sites affected by LTD4 and PGD2 included capillaries, superficial and deep venules, and arterioles. LTB4 elicited a transient wheal and flare, followed in 3-4 hr by induration that was characterized by a dermal infiltrate comprised predominantly of neutrophils. The combination of LTB4 and PGD2 elicited tenderness and increased induration associated with a more intense neutrophil infiltration. Thus, the products of the 5-lipoxygenase pathway of arachidonic acid metabolism in nanomole amounts can induce cutaneous vasodilation with edema formation and a neutrophil infiltrate, and these responses are enhanced by a cyclooxygenase pathway product, PGD2.

Biopsy↗
PubMed1983

The effect of indomethacin on the contractile response of the guinea-pig lung parenchymal strip to leukotrienes B4, C4, D4 and E4.

Indomethacin (1 microgram ml-1) almost totally inhibited the dose-dependent contractile response of isolated lung parenchymal strips of the guinea-pig (GPLS) to leukotriene B4 (LTB4) over the concentration range 0.18-18 nM. LTC4 (0.63 pM-63 nM)-induced contractions of GPLS were not significantly inhibited by indomethacin (1.0 and 10.0 micrograms ml-1) except when the highest LTC4 concentration (63 nM) was tested in the presence of indomethacin (10 micrograms ml-1). LTD4 (1.3 fM-13 nM)-induced contractions of GPLS were not significantly inhibited by indomethacin (0.1-10 micrograms ml-1) except for contractions induced by concentrations of LTD4 greater than 0.13 nM and 13 nM. Indomethacin 1 microgram ml-1 and 10 micrograms ml-1 inhibited the contractile response to 13 nM LTD4 by 37 and 16% respectively. LTE4 (2.3 fM-23 nM)-induced contractions of GPLS were not significantly inhibited by indomethacin (0.1-10 micrograms ml-1). Contraction due to LTE4 23 pM was significantly potentiated by indomethacin (1 microgram ml-1). Clotrimazole (10 microM) significantly inhibited LTD4-induced contractions of GPLS at concentrations greater than 13 pM but had no significant effect on LTC4-induced contractions. Cyclo-oxygenase products, probably principally thromboxane A2, are important secondary mediators of LTB4-induced contractions of GPLS but make little or no contribution to contractions of GPLS induced by LTC4, LTD4, and LTE4, except at higher concentrations of LTD4 and possibly LTC4. Certain concentrations of LTE4 may generate bronchodilator PGE2 in GPLS.

Animals↗
PubMed1983

Systemic hemodynamic effects of leukotrienes C4 and D4 in the rat.

Although local administration of the sulfidopeptide leukotrienes into cutaneous and coronary vascular beds indicates that these naturally occurring metabolites of arachidonic acid are vasoconstrictors, their systemic administration has produced both pressor and depressor responses. The systemic hemodynamic effects of intravenous leukotriene C4 (LTC4) and leukotriene D4 (LTD4) were assessed in ether-anesthetized rats and compared with the effects produced by equimolar doses (2 X 10(-10) to 4 X 10(-8) mol/kg) of norepinephrine and angiotensin. Mean arterial pressure, right atrial pressure, and cardiac output (electromagnetic flowmetry) were recorded during bolus administrations of these vasoactive compounds. LTC4 and LTD4 had similar hemodynamic effects that were characterized by moderate pressure elevations produced by dose-dependent increases in total peripheral resistance, since cardiac output declined. Although the peak mean arterial pressure levels produced by LTC4 and LTD4 (135 +/- 7 and 129 +/- 5 mmHg, respectively) were less than those by norepinephrine (157 +/- 3 mmHg) and angiotensin (174 +/- 5 mmHg), the peak total peripheral resistance values of LTC4 and LTD4 (2.23 +/- 0.32 and 1.86 +/- 0.17 mmHg X ml-1 X min-1, respectively) were between those of the well-known vasopressors, norepinephrine (1.50 +/- 0.09) and angiotensin (2.72 +/- 0.41). The pressor response to LTC4 and LTD4 was less marked than that to norepinephrine and to angiotensin because of the concomitant reduction in cardiac output. These results indicate that LTC4 and LTD4 are systemic vasoconstrictors with potencies similar to those of norepinephrine and angiotensin.

Angiotensins↗
PubMed1983

Indomethacin potentiates the pulmonary response to aerosol leukotriene C4 in the guinea pig.

Aerosol administration of leukotriene (LT) C4 to anesthetized, mechanically ventilated guinea pigs results in significant dose-dependent decrements in dynamic compliance (Cdyn) and pulmonary conductance (GL) when the concentration of LTC4 in the nebulizer is in the range of 0.5 to 5 micrograms/ml. Pretreatment with indomethacin, 30 mg/kg given intraperitoneally, significantly potentiates the decrements in Cdyn and GL elicited by aerosol LTC4 at 1 microgram/ml. Potentiation of the pulmonary response is seen even with an aerosol LTC4 concentration of 0.3 micrograms/ml, which alone produces only minimal changes in pulmonary mechanics in control animals. These findings suggest that bronchodilator prostaglandins are important inhibitory modulators of this pulmonary response and that secondary thromboxane release probably does not contribute to the response to inhaled LTC4. The effect of indomethacin pretreatment in augmenting the pulmonary response to aerosol LTC4 in the guinea pig may have relevance for the phenomenon of asthma induced in humans by ingestion of nonsteroidal anti-inflammatory agents.

Aerosols↗
PubMed1983

Bioconversion of C-6 sulfidopeptide leukotrienes by the responding guinea pig ileum determines the time course of its contraction.

The naturally occurring sulfidopeptide leukotrienes, leukotriene (LT) C(4) (LTC(4)) [5(S)-hydroxy - 6(R) - S - glutathionyl - 7,9 - trans, 11,14 - cis - eicosatetraenoic acid] and its cysteinylglycine (LTD(4)) and cysteinyl (LTE(4)) analogs, which are derived by peptide cleavage, differ in the concentrations required to elicit comparable contractions of the guinea pig ileum, with respective potencies of 1.2:5:1. The effect of the ongoing bioconversion of LTC(4) and LTD(4) on the contractile response of the guinea pig ileum to each was determined by recording the pattern of the contraction and quantitating the initial agonist and its metabolic products. The contraction was elicited by radiolabeled agonist, and its conversion products were sampled at defined intervals and resolved by their retention times on reverse-phase high performance liquid chromatography. After a latent period of 60 s. LTC(4) initiated a linear response, followed by a slower, progressive response to a maximum level that was maintained without relaxation. The metabolic conversion of LTC(4) was <5% during the linear phase of contraction and complete inhibition of bioconversion of LTC(4) to LTD(4) by the presence of serine-borate complex did not alter the pattern of the spasmogenic response. As the maximum response in the presence of serine-borate complex was three-quarters of that obtained without the inhibitor of bioconversion, the predominant response was to LTC(4) itself. The spasmogenic response of the ileum to LTD(4) was immediate, linear to a maximum level, and immediately followed by a marked relaxation. That the failure of LTD(4) to sustain a contraction was due to its immediate, rapid, and quantitative conversion to the less potent LTE(4) was established by pharmacologically inhibiting and anatomically deleting the converting activity. In the presence of L-cysteine the conversion of LTD(4) to LTE(4) was largely inhibited and the maximum contractile response was well maintained. After anatomic removal of the mucosa that contained the LTD(4) dipeptidase activity, the longitudinal smooth muscle preparation gave a maximal response to LTD(4) that was fully maintained. Thus, bioconversion is not a prerequisite for the spasmogenic activity of LTC(4) and accounts for the transient response of the ileum to LTD(4).

Animals↗
PubMed1983

Specific receptors for leukotriene C4 on a smooth muscle cell line.

Specific receptors for leukotriene C4 (LTC4) have been identified on an intact smooth muscle cell line, DDT1 MF-2 cells derived from the Syrian hamster vas deferens. Specific [3H]LTC4 binding at a fixed input at 4 degrees C was rapid, reached a plateau at 86% of total binding at 60 min, and was reversible upon addition of excess homoligand. With incremental inputs of radioligand and a constant cell number, specific [3H]LTC4 binding reached a plateau indicative of saturable binding sites. LIGAND analysis of the Scatchard plot demonstrated a single high affinity binding site with a dissociation constant (Kd) of 5 nM. With incremental inputs of unlabeled LTC4, LIGAND analysis of the Scatchard plot demonstrated a single high affinity site with a Kd of 4.4 nM and in some experiments an additional low affinity site with a Kd of 634 nM. The myotonically active structural analogues of LTC4, 5(R),6(S)-LTC4, 11-trans-LTC4, and C1-monoamide-LTC4, competed effectively with radiolabeled LTC4 such that the relative Kd values of these heteroligands were within one log of that of the homoligand. In contrast, the other native sulfidopeptide leukotrienes, leukotriene D4 and leukotriene E4, exhibited relative Kd values that were 2-3 logs less than that of LTC4. Thus, the high affinity receptor on the DDT1 smooth muscle cell line is specific for a single constituent, LTC4, of slow reacting substance of anaphylaxis.

Animals↗
PubMed1983

Conversion of leukotriene D4 to leukotriene E4 by a dipeptidase released from the specific granule of human polymorphonuclear leucocytes.

Leukotriene D4 (LTD4), the most active spasmogenic leukotriene constituent of the slow reacting substance of anaphylaxis was converted by suspended human polymorphonuclear leucocytes (PMNs) to a single, less polar metabolite which was not further catabolized. This product was identified as leukotriene E4 (LTE4) by its retention time during reverse phase-high performance liquid chromatography (RP-HPLC) and subsequent bioassay on the guinea-pig ileum. LTD4 with a retention time of 21 +/- 1.6 min (mean +/- SD) and a contractile activity of 5.0 +/- 0.4 u./pmol (mean +/- SD) was quantitatively converted extracellularly by PMNs to LTE4 with a retention time of 26 +/- 1.8 min and a contractile activity of 1.2 +/- 0.3 u./pmol. Subcellular fractionations of PMNs revealed the recovered LTD4-to-LTE4 converting activity, termed LTD4 dipeptidase, to be localized only in he granule fraction. There was a time- and calcium-dependent extracellular release of LTD4 dipeptidase in association with lysozyme (r = 0.97, n = 16, P less than 0.001), a constituent of both specific and azurophilic granules, in the absence of release of cytoplasmic lactate dehydrogenase (LDH) and of beta-glucuronidase from the azurophilic granule. Phorbol myristate acetate (PMA), which selectively induces secretion of specific granules, released lysozyme and the LTD4 dipeptidase in a constant dose-dependent manner from PMNs (r = 0.96, n = 8, P less than 0.001). Calcium ionophore A23187 at concentrations less than 10(-7) M stimulated the parallel secretion of LTD4 dipeptidase and lysozyme (r = 0.91, n = 9, P less than 0.005), dipeptidase and lysozyme (r = 0.91, n = 9, P less than 0.005), whereas higher concentrations resulted in secretion of beta-glucuronidase and additional lysozyme without further release of dipeptidase. Thus, human PMNs can convert LTD4 to LTE4, a less vasoactive and spasmogenic leukotriene, via the secretion of a dipeptidase associated with the specific granules.

Cells, Cultured↗
PubMed1983

Immunologic and ionophore-induced generation of leukotriene B4 from mouse bone marrow-derived mast cells.

Mouse bone marrow-derived mast cells differentiated in vitro and sensitized with monoclonal IgE respond to antigen-initiated activation-secretion with the generation of leukotriene B4 (LTB4), a highly potent chemotactic factor. The antigen-initiated net percent release of the secretory granule marker beta-hexosaminidase and the generation of immunoreactive LTB4 and of immunoreactive leukotriene C4 (LTC4) were not diminished by washing the cells before challenge, indicating that interaction of the antigen occurred with the IgE fixed on cell membranes and was not due to phagocytosis of immune complexes formed in the fluid phase. The parallel dose-response relationship for the antigen-induced release of the performed mediator and the generation of both leukotrienes along with the superimposable time courses of their extracellular appearance indicate the origin of these mediators from a common cell type with IgE receptors. Resolution by reverse phase-high performance liquid chromatography (RP-HPLC) of the leukotrienes released from unsensitized cells by ionophore A23187 and from sensitized cells by the specific antigen revealed that the generation of LTB4 was accompanied by the production of the two diastereoisomers of 6-trans-LTB4, which were not immunoreactive. The immunoreactive LTB4 eluted from RP-HPLC at the same retention time as synthetic LTB4 was present in similar nanogram quantities when measured by either radioimmunoassay or integrated absorbance at 269 nm and exhibited a chemotactic activity for human neutrophils on a weight basis comparable to that of synthetic LTB4. The overall recoveries after RP-HPLC of immunoreactive LTB4 released from ionophore A23187-activated, bone marrow-derived mast cells and of added tritiated synthetic LTB4 in separate experiments with ionophore-activated cells were comparable and greater than 78%. The maximum generation of LTB4 by ionophore A23187-activated cells of 7.9 +/- 2.5 ng/10(6) cells (mean +/- SD), occurring at 40 min, was greater than the maximum generation of 4.5 +/- 0.8 ng/10(6) cells, with immunologic stimulation occurring 5 min after antigen challenge of sensitized cells. The initial rate of LTB4 generation after perturbation of the IgE-Fc receptors, however, exceeded that following ionophore A23187 stimulation and may represent one important variable in establishing a significant chemotactic gradient.

Animals↗
PubMed1982

Chemical studies on slow reacting substances/leukotrienes.

The family of eicasanoids, biologically active metabolites of polyunsaturated C20 fatty acids such as arachidonic acid, has recently been enlarged by the recognition of a new biosynthetic pathway leading to the leukotrienes, including the compounds described two decades ago as 'slow reacting substances'. These biologically potent substances are involved in regulation of the immune response and also as mediators in various disease states. This account presents a brief history of this field, an overview of the biological relevance of leukotrienes, and a discussion of the investigations which led to the clarification of the molecular structures, pathway of biosynthesis and total chemical synthesis of the leukotrienes, including leukotrienes A, B, C, D and E (LTA-LTE). As a result of the synthetic work these rare substances are available for the first time in pure form and in quantities sufficient for biological and medical studies. Also reviewed are recent discoveries with regard to the development of inhibitors of leukotriene biosynthesis and anti-leukotrienes.

Animals↗
PubMed1982

Bronchoconstrictor effects of leukotriene C in humans.

Maximum expiratory flow rate at 30 percent of vital capacity above residual volume served as an index of airway obstruction in comparing the effects of leukotriene C and histamine administered by aerosol to five normal persons. Leukotriene C was 600 to 9500 times more potent than histamine on a molar basis in producing an equivalent decrement in the residual volume. The leukotriene C response was slow in onset and prolonged, reminiscent of the effects of aerosol allergen challenge in asthmatic allergic subjects.

Adult↗
PubMed1982

A review of recent contributions on biologically active products of arachidonate conversion.

Leukotrienes (LTs) C4, D4 and E4, the recognized components of slow reacting substance of anaphylaxis (SRS-A), have previously been shown to have contractile activities for guinea pig pulmonary and ileal smooth muscles; LTB4 has been shown to possess chemotactic activity for neutrophils in vitro. Based on data obtained by the use of structural analogs of the SRS-A LTs and of LTB4, we have recently determined a number of the structural bases for the biological function of each moiety. With regard to the SRS-A leukotrienes, analogs differed from the native structures in the position of the peptide side chain and/or the hydroxyl group, the number and position of ethylenic bonds, the chirality at optically-active centers, or the structures of the four polar substituents in the C-1 to C-6 region. Analogs of LTB4, differing in the stereochemistry of their ethylenic bonds, were evaluated for chemotactic activity both in vitro, using human neutrophils, and in vivo intracutaneously in the rhesus monkey. We propose that true receptors exist on the pulmonary parenchyma of the guinea pig for the SRS-A LTs and on the primate neutrophil for LTB4. Further, LTC4, LTD4 and LTE4 have been shown to elicit a wheal and prolonged flare in human skin, whereas LTB4 evokes a time-dependent induration. The interaction of these secondary mediators may be critical to a fully developed host inflammatory response to both immunologic and non-immunologic injury.

Animals↗
PubMed1982

Studies on the mechanism of formation of the 5S, 12S-dihydroxy-6,8,10,14(E,Z,E,Z)-icosatetraenoic acid in leukocytes.

Incubation of peripheral blood leukocytes with arachidonic acid (and ionophore A23187) led to the formation of leukotriene B4, delta 6-trans-leukotriene B4, delta 6-trans-12-epi-leukotriene B4, 5-hydroxy-icosatetraenoic acid, 12-hydroxy-icosatetraenoic acid and of 5S,12S-dihydroxy-6,8,10,14-(E,Z,E,Z)-icosatetraenoic acid (5S,12S-DiHETE). Incubation of leukocytes with leukotriene A4 resulted in the formation of leukotriene B4 and of its two delta 6-trans-isomers but not of the 5S, 12S-DiHETE. 18O2 labeling experiments have shown that the hydroxyl groups at C5 and C12 in the 5S,12S-DiHETE are derived from molecular oxygen. The tetraacetylenic analog of arachidonic acid was found to be potent inhibitor of the formation of the 5S,12S-DiHETE whereas it potentiated the synthesis of the 5-hydroxy acid and of leukotriene B4. Addition of the 12-hydroxy-icosatetraenoic acid to leukocytes, or of the 5-hydroxy-icosatetraenoic acid to a suspension of platelets caused the formation of the 5S,12S-DiHETE. It is concluded that the 5S,12S-DiHETE is not derived from leukotriene A4 but is a product of the successive reactions of arachidonic acid with two lipoxygenases of different positional specificities.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1982

Oxidative inactivation of leukotriene C4 by stimulated human polymorphonuclear leukocytes.

Leukotriene C(4) (LTC(4)) was metabolized by human polymorphonuclear leukocytes (PMNs) stimulated with phorbol myristate acetate (PMA) into three sets of products. These products differed in mobility on reverse-phase high-performance liquid chromatography (RP HPLC) from LTC(4) and also from leukotriene D(4) (LTD(4)) and leukotriene E(4) (LTE(4)), the sequential products of peptide cleavage of LTC(4). Products I, II, and III were eluted as doublets with an average retention time for each doublet of 7.5 +/- 0.3, 10.5 +/- 0.6, and 16.3 +/- 1.1 min (mean +/- SD), respectively, as compared with 13.8 min for LTC(4). Doublet I material was biologically inactive and showed <5% of the immunoreactivity of LTC(4), doublet II material had 1% of the spasmogenic activity of LTC(4) on the guinea pig ileum and was equally immunoreactive, and doublet III material was neither biologically active nor immunoreactive. When [14,15-(3)H]LTC(4) and [(35)S]LTC(4) were metabolized, all three doublet products retained the (3)H label, whereas only the doublet I and doublet II products retained the (35)S label. The UV absorbance spectra of the three sets of metabolites were as follows: doublet I, maximum at 280 nm with shoulders at about 270 and 290 nm; doublet II, maximum at 284.5 nm with shoulders at about 275 and 295 nm; and doublet III, maximum at 269 nm with shoulders at about 259 and 279 nm. The metabolism of LTC(4) to the three classes of functionally inactive products by stimulated PMNs was completely blocked by catalase and azide, indicating a requirement for H(2)O(2) and myeloperoxidase. When hypochlorous acid (HOCl)-considered to be a natural product of the interaction of myeloperoxidase, H(2)O(2), and chloride ion-was formed chemically and allowed to react with LTC(4), the resulting products were indistinguishable by UV and HPLC analyses from the doublet II and doublet III metabolites of LTC(4). The doublet II products were identified as the two diastereoisomeric sulfoxides of LTC(4) by comparison with synthetic reference compounds. The doublet III products were shown to be identical with synthetic samples of (5S, 12S)- and (5S, 12R)-6-trans-LTB(4). The formation of two diastereoisomeric LTC(4) sulfoxides and 6-trans-LTB(4) can be explained in terms of an S-chlorosulfonium ion as the initial reactive intermediate, which subsequently undergoes conversion to product II by hydrolysis and product III by carbocation formation.

Catalase↗
PubMed1982

Generation of leukotriene C4 from a subclass of mast cells differentiated in vitro from mouse bone marrow.

Bone marrow-derived mast cells, differentiated in vitro, demonstrate surface IgE, receptors and contain histamine in metachromatic granules, which are composed of chondroitin sulfate E proteoglycan rather than heparin proteoglycan. Activation of this subclass of mast cells with calcium ionophore A23187 resulted in generation of immunoreactive C-6-sulfidopeptide leukotriene in a dose- and time-dependent fashion. Isolation of immunoreactive C-6-sulfldopeptide leukotriene by reverse-phase high-performance liquid chromatography (RP-HPLC) revealed a retention time and a specific biologic activity identical to those of synthetic leukotriene C4 (LTC4). Neither radiolabeled nor immunoreactive conversion products of [3H]LTC4/LTC4 were recognized during RP-HPLC resolution of the supernatants. The failure of fresh bone marrow cultures to generate C-6-sulfidopeptide leukotriene in response to ionophore indicates that leukotriene generation is dependent upon cellular differentiation into a mast cell population. The amount of LTC4 generated during optimal ionophore stimulation, 90.9 +/- 7.5 ng per 10(6) cells, contrasts with the relatively low amounts of C-6-sulfidopeptide leukotriene generated by the conventional heparin-containing rat mast cells or mouse mastocytoma cells.

Animals↗