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Biomedical subjects

M Damon

Publications and source records attributed to M Damon.

At least 55 records · Page 3Linked to original sources
PubMed1987

Arachidonic acid metabolism in alveolar macrophages. A comparison of cells from healthy subjects, allergic asthmatics, and chronic bronchitis patients.

Arachidonic acid (AA) metabolism was studied in preparations of purified human alveolar macrophages (AM) from healthy subjects (HS = 5), allergic asthmatics (ABA = 9) and chronic bronchitis patients (CB = 7). AM incubated for 6 to 24 h in the presence of labeled AA and for an additional 5 h without labeled AA, released cyclooxygenase and lipoxygenase products into the medium. The study of the metabolites showed that the most abundant sulfidopeptide-leukotriene, was LTD4 as analyzed by TLC and identified by reversed phase HPLC. The release of LTD4 was time-dependent but it was shown to be significantly higher (p less than 0.01) in AM from ABA or CB than in those from HS. TLC analysis of radioactivity distributed between the different lipid classes at 24 h revealed more labeling in AM phospholipids from ABA and CB than in those from HS, and was reflected in phosphatidylethanolamine and phosphatidylinositol species. After 5 h without labeled AA the distribution was marked, by different in triglycerides, with a greater proportion of radioactivity in the control cells than in the pathological macrophages. Thus, the pathological lung state is an important factor affecting the release of LTD4 and the distribution of AA into cellular phospholipids. The differences observed between HS and ABA or CB phospholipid distribution suggests the existence of 2 different sources of AA release, one for inflammatory macrophages and another for quiescent cells.

Adolescent↗
PubMed1987

Enhanced alveolar cell luminol-dependent chemiluminescence in asthma.

Alveolar macrophages (AM) appear to be one type of cells of the bronchial inflammation often involved in patients with asthma. These cells were demonstrated to generate highly reactive toxic species of oxygen in many pulmonary disorders; however, this was never demonstrated in asthma. The respiratory burst of bronchoalveolar lavage AM was studied in 12 subjects with asthma and in five control subjects by luminol-enhanced chemiluminescence (Cl). Both in subjects with asthma and in healthy subjects, the maximal value of Cl was obtained after 10 to 13 minutes of stimulation by opsonized zymozan. Baseline values and maximal Cl of AM values were significantly increased (p less than or equal to 0.03 and p less than or equal to 0.01) in subjects with asthma. There was a significant (p less than or equal to 0.01) correlation between maximal Cl of AM and the severity of asthma, assessed by a clinical score defined by Dr. K. Aas. The percentage of bronchoalveolar lavage eosinophils was significantly correlated (p less than or equal to 0.01) for all the subjects with the peak of CL of AM. This study suggests the role of toxic oxygen species in the bronchial inflammation in asthma.

Adult↗
PubMed1987

Arachidonic acid metabolism in a cloned strain of rat pituitary tumor cells: correlation between 15 hydroxyeicosatetraenoic acid release and the prolactin secretory process.

We investigated the involvement of arachidonic acid metabolites in basal and thyrotropin releasing hormone (TRH) stimulated prolactin release by GH3 cells, a cloned strain of rat pituitary tumor cells. GH3 cells spontaneously released 9 and 15 HETEs and the 15 HETE release was greater than that of 9 HETE. When the cells were challenged by 10(-5) M AA, they were able to produce 5, 9, 12 and 15 HETEs. 10(-6) M TRH only stimulated the release of the two metabolites synthesized by the basal cells (15 and 9 HETEs). This release depended on the length of stimulation by TRH. When both AA and TRH were added, there was an increase in 15 and 9 HETE production. In all cases, more 15 HETE was released than other metabolites. In dose-response studies using TRH concentrations of 10(-6) M to 10(-12) M, the highest level of 9 HETE release was obtained at 10(-11) M TRH and the highest release of 15 HETE was at 10(-9) M TRH. PRL secretion by GH3 cells challenged by TRH showed the same pattern as 15 HETE release, and the correlation between PRL and 15 HETE was significant (p less than 0.001). These data indicate that 15 HETE is the lipoxygenase metabolite released in the largest amounts by GH3 cells and suggest some physiological interaction between 15 HETE and TRH in the control of PRL secretion.

Animals↗
PubMed1987

[Oxygen free radicals and bronchial asthma].

Oxygen free radicals are released generally by many cells during phagocytosis and cell activation. In asthmatics, some experimental evidence indicates that oxygen free radicals may be considered to be chemical mediators of anaphylaxis. They are released by macrophages, eosinophils and neutrophils, the cells that are found in bronchoalveolar lavage. They may explain some pathological changes, such as hardening of the airways, bronchial hyper-reactivity and inflammation. Therapeutic implications are discussed.

Adolescent↗
PubMed1987

Effect of chronic treatment with a purified flavonoid fraction on inflammatory granuloma in the rat. Study of prostaglandin E2 and F2 alpha and thromboxane B2 release and histological changes.

S-5682 (Daflon-500 mg), a purified flavonoid fraction, consisting of 90% diosmin (a flavone derivative) and 10% hesperidin (a flavanone derivative), was administered to rats by intubation in the daily dose of 100 mg/d. 15 days after the start of treatment, polyurethane sponges were implanted in the subcutaneous connective tissue in the dorsolumbar region under rapid ether anaesthesia. Similar fragments of sponge were implanted in a group of control animals who received the vehicle (saccharose syrup) only, also by the oral route. The rats were sacrificed in fractions of 7 animals drawn from each of the two groups (control and treated) after 4, 8, 16 and 30 days (only 5 animals from each group on day 30) after implantation of the polyurethane sponges. The granulomas formed were removed, weighed and their prostaglandin (PG)E2, PGF2 alpha and thromboxane (Tx)B2 contents were determined. In addition a full cell count (polymorphs, lymphocytes, macrophages, plasmocytes and giant cells) was performed and the animals were histologically examined. The results show that treatment of the animals with S-5682 had the following effects: 1. A significant fall in the mean weight of the granulomas formed after 4 and 8 days was observed, reflecting inhibition of oedema formation during the early phase of the inflammatory reaction. 2. The synthesis of PGE2 (78.5% inhibition on day 4) and PGF2 alpha (45.2% on day 16) was inhibited. 3. There was very early inhibition of TxB2 synthesis (59.5% inhibition on day 4). 4. A later reduction in cell migration towards the inflammatory focus occurred which was statistically significant on day 16 (49.6% reduction in the total number of migrant cells). 5. Multiple histological aspects of the acute inflammatory reaction (diapedesis of polymorphs, lymphocytes, histiocytes and macrophages) and features of the chronic inflammatory reaction (newly formed microvascularisation of the granuloma tissue, perivascular oedema, presence of collagen fibres) were improved.

Animals↗
PubMed1986

Glucocorticoid receptors in fibroblasts from synovial tissue. Changes during the inflammatory process. Preliminary results.

There is known to be a significant correlation between the number of glucocorticoid receptors in tissues and their anti-inflammatory effect. In this work, the specific binding of glucocorticoids was studied in inflammatory fibroblasts. Human fibroblasts were obtained from the knee joint of a rheumatoid patient undergoing surgery; experimental fibroblasts were from rat granulomas. The same study was carried out in quiescent synovial fibroblasts from a healthy subject (post-traumatic amputation) and from rat subcutaneous conjunctive tissue. Fibroblasts were obtained by explant cultures and subcultures in monolayers. The stimulation state of cells was evaluated by the amounts of PGE2 and PGF2 alpha released into the culture media. Analysis of the proportions of steroid bound to whole cells showed evidence of specific glucocorticoid receptors in all fibroblasts. Their number was three times higher in cells from inflammatory tissues than from controls. This increased number of receptors in inflammatory cells could be the result of the action of one or more mediators that promote their biosynthesis.

Animals↗
PubMed1986

Effect of nedocromil sodium on TXB2, LTB4 and LTD4 synthesis by alveolar macrophages from asthmatic patients.

Arachidonic acid metabolites may play a role in the pathophysiology of bronchial asthma, influencing bronchial tone, airways inflammation and bronchial hyperreactivity. This study was designed to investigate the effect of nedocromil sodium, at a range of concentrations, on the metabolism of arachidonic acid released from alveolar macrophages (AMs) obtained by bronchoalveolar lavage in healthy and asthmatic subjects. The only effect of nedocromil sodium observed in this study was a slight decrease in LTD4 synthesis by AMs from asthmatic patients. This possible effect of nedocromil sodium on LTD4 metabolism deserves further investigation.

Asthma↗
PubMed1985

Production of mononuclear cell factor by mononuclear phagocytes from rheumatoid synovial fluid.

Collagenase-and PGE1-stimulating activities (mononuclear cell factor or MCF) have been found in culture supernatants from synovial fluid macrophages (SF-M phi) of patients wih rheumatoid arthritis. The apparent molecular weight of the MCF activity present in SF-M phi supernatants was between 15-20,000 daltons, which is similar to interleukin I. All the SF-M phi supernatants from patients tested showed the MCF activity. Our study presents evidence for MCF production by monocyte-macrophages at the local site of the lesion.

Adult↗
PubMed1983

Purification and mass spectrometry identification of leukotriene D4 synthesized by human alveolar macrophages.

Human AM obtained by BAL from normal subjects and asthmatic patients converted [1-14C]-AA into a polar labeled metabolite. The structure of this metabolite, after two successive purifications on TLC (silicagel plates then reversed phase plates) and mass spectrometric analysis was shown to be identical to an authentic sample of LTD4. The amount of LTD4 recovered in the culture medium of AM was attempted to be related to pathological lung profile. In our experimental conditions AM from allergic asthmatics synthetized more LTD4 than cells from healthy subjects and from aspirin sensitive asthmatic patients.

Adolescent↗
PubMed1983

[Collection of mature ovocytes during cycles with spontaneous ovulation for the purpose of in vitro fertilization].

In vitro fertilization was attempted during a spontaneous cycle in 17 out of 97 patients. Preovulatory urinary estrogen and LH maximas were assayed in order to time celioscopy 24 hours after the onset of the triggering urinary LH maxima. In 8 patients, comparison with plasmatic LH shows that the timing of spontaneous ovulation can be precisely predicted from urine assays. However, when the triggering LH release is weak, LH must be above or equal to 25 IU/g of creatinine with a creatininuria above or equal to 0.4 g/l in two urine samples at a three-hour interval.

Estrogens↗
PubMed1983

[In vitro development of human ovocytes collected during spontaneous ovulation. Effect of the biochemical composition of the follicular fluids].

Development of the in vitro cultured and fertilized ovocyte appears to be improved when progesterone and estrogen concentrations in the follicular fluid are above 2 000 and 1 000 ng/ml respectively, with a A/E ratio under 1 and a PGE/PGF ratio above 0.8. Such criteria are only infrequently fulfilled: once in seven cases. They were found in one of the two patients who had a pregnancy after in vitro fertilization during induced ovulation. Division of ovocytes from spontaneous ovulation was recorded in several instances in spite of a less propitious composition of the follicular fluid.

Androgens↗
PubMed1983

[Effect of the hormonal environment on the human oocyte and its later development in vitro].

The biosynthesis of progesterone by the granulosa cells that come from follicles from which the oocyte has been fertilized and has divided in vitro is far superior to that from the cells coming from follicles in which the oocyte has failed to develop. This result is in accordance with the raised levels of progesterone and the influence of androgens on lower levels of oestrogens in follicular fluid that evolved favourably. In the same follicles the ratio of concentrations of prostaglandins PGE2 to PGF2 alpha is twice as high as in the liquid from other follicles.

Androgens↗
PubMed1982

GLC/MS identification of new pregnenolone metabolites in confluent embryonic rat fibroblast cultures.

Four new metabolites and their fatty acid derivatives have been identified as components of the steroid metabolic pathway in rat embryo fibroblasts grown during the confluent phase in the presence of [4-14C]-pregnenolone and [4-14C]-progesterone. These compounds are 3 alpha, 20 alpha and 3 beta, 20 alpha-dihydroxy-5 alpha-pregnanes, 4-pregnene-3 alpha, 20 alpha-diol and 5 alpha-pregnane-3 beta, 20 alpha, 21-triol. The labelled free and esterified steroids synthetized in the cells were released into the culture medium. The purpose of this study was to demonstrate that, besides t.l.c. enzymatic and chemical reactions, g.l.c./mass spectrometry coupling is a powerful tool for identifying the structures of sub-microgram amounts of radiolabelled steroids. The consequent metabolic features are discussed in terms of steroid cellular biosynthesis and kinetics.

Animals↗