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Biomedical subjects

R Scicchitano

Publications and source records attributed to R Scicchitano.

At least 37 records · Page 2Linked to original sources
PubMed1993

A metabolite of substance P, SP7-11 is involved in the pathogenesis of inflammatory joint disease.

The possibility that neuropeptides, in particular members of the tachykinin family are involved in inflammatory joint disease is widely disputed. Both clinical and experimental observations indicate that the tachykinin substance P (SP) may be involved in the pathogenesis of arthritis. We have studied the effects of tachykinins and the metabolites of SP on chondrocyte function. We have shown that the C-terminal pentapeptide sequence; H-Phe-Phe-Gly-Leu-Met-NH2 is biologically active in bovine chondrocyte cultures. The production of SP7-11 is limited by hydrolysis of the intact peptide by neutral endopeptidase (E.C. 3.4.24.11). The regulation of this enzyme would modulate the activity of substance P on articular cartilage chondrocytes.

Amino Acid Sequence↗
PubMed1993

Activation of human neutrophils by tachykinins: effect on formyl-methionyl-leucyl-phenylalanine- and platelet-activating factor-stimulated superoxide anion production and antibody-dependent cell-mediated cytotoxicity.

This study examines the contribution of tachykinins to the processes of inflammation. Neurokinin A (NKA), neurokinin B (NKB) and eledoisin (E) but not kassinin (K) have similar effects to substance P (SP) in priming neutrophils for increased superoxide anion (O2-) production in response to formyl-methionyl-leucyl-phenylalanine (FMLP). This similarity in activity may be due to the carboxy amino acid terminal end of these tachykinins being highly conserved. This was confirmed by demonstrating that SP fragment 7-11 (SP7-11) had the same priming effect as the whole molecule, whereas, the amino end fragment 1-4 (SP1-4) inhibited the response to FMLP. The priming effect of tachykinins was not confined to a single stimulus, such as FMLP, since NKA, NKB and SP also enhanced O2- production stimulated by platelet-activating factor (PAF), an important mediator of inflammation but a weak stimulus of O2- production on its own. In addition, all the tachykinins studied increased neutrophil antibody-dependent cell-mediated cytotoxicity (ADCC) towards opsonized target cells. In contrast to their effects on FMLP-induced O2- production, both SP fragments, SP1-4 and SP7-11, stimulated neutrophil ADCC and had a synergistic effect when used together.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1992

Failure of tachykinins including substance P and its fragments to influence proteoglycan and protein synthesis in bovine chondrocytes in vitro.

Adult bovine articular chondrocytes were exposed to substance P, neurokinins A and B or substance P fragments, SP1-4, SP1-6 and SP7-11 in vitro. Proteoglycan synthesis was assessed by measuring proteoglycans which were released into the culture medium or incorporated into the cell layer. The intact tachykinins or substance P fragments had no direct effect on proteoglycan synthesis. Nor was total protein production affected. Gel chromatography, under dissociative conditions, revealed that sulphated proteoglycans detected in the medium or cell layer following treatment of chondrocytes with substance P, contained proteoglycans of similar molecular weight to those produced by cells exposed only to diluent controls. Therefore, we conclude that the acceleration of arthritis by substance P does not appear to be mediated through an effect on chondrocyte synthetic function.

Amino Acid Sequence↗
PubMed1992

Airway hypocapnia increases microvascular leakage in the guinea pig trachea.

We have previously shown that airway hypocapnia induced bronchoconstriction in the guinea pig lung by releasing tachykinins. To examine whether airway hypocapnia could also cause an increase in airway microvascular leakage, a tracheal segment was isolated in vivo in anesthetized guinea pigs and unidirectionally ventilated (200 ml/min) for 1 h with fully conditioned air (0% CO2) or isocapnic gas (5% CO2). The lungs were ventilated through a distally placed tracheal cannula. Microvascular leakage was quantitated by the injection of Evans blue (EB) and its extraction from the tracheal segment. EB extravasation was increased in tracheae exposed to 0% CO2 (52.3 +/- 2.0 micrograms/g wet tissue) compared with tracheae exposed to 5% CO2 (26.4 +/- 2.9 micrograms/g; p less than 0.05) and to tracheae from spontaneously breathing guinea pigs (25.2 +/- 2.3 micrograms/g; p less than 0.05). Groups of animals in which trachea were unidirectionally ventilated with 0% CO2 were then pretreated with a range of drugs in an attempt to determine the mediators responsible for the microvascular leakage with 0% CO2. Capsaicin and morphine pretreatment did not significantly alter 0% CO2-induced EB extravasation, and phosphoramidon prevented rather than increased extravasation, suggesting that tachykinins did not play a role. The hypocapnia-induced increase in microvascular leakage was, however, prevented by indomethacin pretreatment and significantly attenuated by dazmegrel, a thromboxane synthetase inhibitor. We conclude that airway hypocapnia causes microvascular leakage in the guinea pig trachea and that this effect is mediated by prostaglandins and/or thromboxane.

Animals↗
PubMed1992

Plasma elastin-derived peptide levels in normal adults, children, and emphysematous subjects. Physiologic and computed tomographic scan correlates.

Pulmonary emphysema is likely to be the result of elastic tissue digestion by unrestrained elastase activity in the lung. Elastin breakdown by elastases results in the release of soluble elastin fragments (EDP), which may be measured in plasma by an ELISA. Plasma EDP levels measured using an ELISA were determined in the following groups: disease-free children (n = 24), 0.162 +/- 0.082 ng/ml; disease-free adult nonsmokers (n = 114), 1.74 +/- 0.8 ng/ml; smokers (n = 68), 2.76 +/- 4.59 ng/ml; reformed smokers (n = 43), 1.91 +/- 1.14 ng/ml. Adults with established pulmonary emphysema (n = 50), as defined by bullous formation on the chest radiograph, had levels of 50.83 +/- 24.8 ng/ml, significantly higher than the disease-free groups at p < 0.01. Pulmonary emphysema can be reflected by pulmonary function tests, especially those that measure the pulmonary elastic properties, and by computed tomographic (CT) scan percent emphysema score. We therefore examined the relationship of plasma EDP to these other indicators of pulmonary emphysema in a separate group of 26 subjects using elastic recoil measurements (K), and a further group of 30 subjects with CT scan percent emphysema score. A significant correlation of p < 0.001 was shown for plasma EDP and K and a significant correlation of p < 0.01 was shown for plasma EDP and CT scan percent emphysema score, these correlations suggesting that plasma EDP levels are indicators of the loss of pulmonary distensibility and of mild to moderate pulmonary emphysema. These findings suggest that pulmonary emphysema is characterized by active elastin breakdown.

Adult↗
PubMed1991

Heparin and heparan sulphate are inhibitors of human leucocyte elastase.

1. Heparin and heparan sulphate strongly inhibited human leucocyte elastase activity in an automated assay using the soluble substrate, n-succinyl-(L-alanine)3-p-nitroanilide (50% inhibition of 250 microliters of 10 micrograms of human leucocyte elastase/ml was obtained with 80 microliters of 2.8 micrograms of heparin/ml and 8 micrograms of heparan sulphate/ml). Less significant inhibition at the same concentrations was seen with the other glycosaminoglycans tested: hyaluronic acid and chondroitin sulphates A-C. 2. Heparin and heparan sulphate also strongly inhibited human leucocyte elastase activity towards insoluble human lung elastin, as determined by an e.l.i.s.a. for soluble elastin-derived peptides released by elastolytic activity on the elastin. This inhibition was shown not to be due to a direct interference of the glycosaminoglycans in the e.l.i.s.a. nor to the inhibition causing a change in the size of the elastin-derived peptides. However, unlike the chromogenic assay with n-succinyl-(L-alanine)3-p-nitroanilide as substrate, where heparin was the more effective inhibitor, in this assay system heparan sulphate was the more effective inhibitor (50% inhibition of 100 microliters of 50 ng of human leucocyte elastase/ml was obtained with 100 microliters of 4.5 micrograms of heparin/ml and 0.8 microgram of heparan sulphate/ml). These results suggest that heparin and heparan sulphate, as components of cellular and basement membranes, are likely to have a role in protecting structural proteins, such as elastin, from the proteolytic activity of human leucocyte elastase.(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗
PubMed1991

Wheat dust-associated respiratory disease in a farming community.

Sixty-six volunteers who considered themselves to have wheat dust-related respiratory disease, were reviewed from a farming community. A spectrum of disease was described ranging from a mild allergic rhinitis limited to periods of wheat dust exposure through to perennial asthma in which wheat dust was but one of several precipitating factors. Approximately half of those with asthma had symptoms limited to times of wheat dust exposure. Results of a limited survey of farmers showed patterns of symptoms similar to those in the volunteer group. Most subjects were atopic with elevated IgE levels, and had positive skin prick tests to environmental allergens. All but one of 65 subjects tested had a positive RAST test to wheat dust antigen. It is concluded that wheat dust associated respiratory tract disease is a significant problem in Australian farming communities, that a particular pattern of asthma can be described, and that IgE mediated reactions contribute to this disease pattern.

Adolescent↗
PubMed1989

Human lung fibroblast-derived granulocyte-macrophage colony stimulating factor (GM-CSF) mediates eosinophil survival in vitro.

Tissue eosinophilia has been reported to occur in pulmonary fibrosis, a disease characterized by chronic inflammation and lung fibroblast proliferation. We have examined the in vitro interaction of these two cell types by determining the in vitro survival of human peripheral blood eosinophils co-cultured with human lung fibroblasts. Survival of eosinophils cultured alone was 10% at day 3 and less than 1% at day 7. In contrast, survival of eosinophils that had been co-cultured with fibroblasts was 98, 90, 73, and 69% at days 3, 7, 10, and 14, respectively. Fibroblast-conditioned medium (CM) elicited a similar result in a dose-dependent fashion. Survival of eosinophils cultured with CM which had been preincubated with a monoclonal-neutralizing antibody to human GM-CSF was inhibited in a dose-dependent manner. Human recombinant-derived GM-CSF supported eosinophil survival in the dose-dependent fashion. Survival at day 7 of eosinophils treated with one single dose of GM-CSF (10 U/ml) was 64%. The effect of fibroblast-CM on eosinophils likely represents true survival since eosinophil proliferation as determined by [3H]thymidine incorporation did not occur. We also report that freshly isolated eosinophils had normal ultrastructural, scanning and transmission electron microscopy characteristics, and were normodense. In contrast, eosinophils co-cultured for 7 days with fibroblasts acquired irregular shapes and became hypodense and partially degranulated. Thus, our results indicate that human lung fibroblast-derived GM-CSF mediates the in vitro survival of human eosinophils.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies↗
PubMed1989

Activation of human neutrophils by substance P: effect on FMLP-stimulated oxidative and arachidonic acid metabolism and on antibody-dependent cell-mediated cytotoxicity.

We show that the neuropeptide, substance P (SP), a putative mediator of neurogenic inflammation, is a potent regulator of mature, human neutrophil function. SP increased neutrophil cytotoxic activity against an antibody-coated target (P815 cells) in a dose-dependent manner. The maximal effect was noted at an SP concentration of 10(-4) M, when cytotoxicity increased from 4.7 +/- 0.9% to 33.4 +/- 10.3%. This effect was not due to toxicity of SP against the target cells and was antibody-dependent. The level of cytotoxic activity induced by SP was comparable to that described for a number of cytokines, such as GM-CSF, under identical assay conditions. SP-induced cytotoxicity was 73.1 +/- 5.8% of that produced by an optimum concentration of conditioned medium known to contain a number of cytokines which activate mature neutrophils. In addition, SP enhanced FMLP-stimulated superoxide anion production by neutrophils in a dose-dependent fashion. Neutrophils preincubated with medium or 7.5 x 10(-5) M SP and then stimulated with 10(-7) M FMLP produced 7.9 +/- 2.7 and 29.9 +/- 3.7 nmol superoxide anion/10(6) cells, respectively. This priming effect of SP was rapid in onset (less than 15 min) and was maximal from 15 to 60 min, after which it declined. It was not reversed by washing the cells and was temperature dependent. SP did not shift the dose-response curve to FMLP to the left, but it enhanced the response to FMLP in the concentration range 10(-8)-10(-6) M. Similarly SP enhanced LTB4 and 5-HETE production by FMLP-stimulated but not calcium ionophore-stimulated neutrophils. Therefore, these data provide evidence that SP regulates a number of neutrophil functions and suggests a mechanism whereby the nervous system may affect the immune response. Furthermore, the regulatory effects of SP on the neutrophil functions studied appear to be similar to those of a number of cytokines that have been previously implicated in inflammation.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1988

The murine IgA-secreting plasmacytoma MOPC-315 expresses somatostatin receptors.

We have previously shown that some neuropeptides had a profound effect on in vitro Ig synthesis (especially IgA) and mitogen-driven murine lymphocyte proliferation. MOPC-315, an IgA-secreting plasmacytoma line, has been extensively used in studies of the regulation of IgA synthesis. In this report we show that the neuropeptide somatostatin (SOM) inhibits proliferation ([3H]thymidine uptake) of MOPC-315 and also inhibits IgA synthesis in vitro. MOPC-315 cells bind both fluorescent SOM and [125I]SOM specifically. On cytofluorimetric analysis, 68 +/- 6.8% (mean +/- SE, n = 7) of MOPC 315 cells labeled with fluorescent SOM and this staining was compatible by incubation with an excess of unlabeled peptide. Specific [125I]SOM binding increased linearly with cell concentration, was rapid and achieved equilibrium after 20 min at 4 degrees C. It was temperature-dependent, readily reversible, and under equilibrium conditions demonstrated a dissociation constant of 1.6 +/- 0.7 nM (mean +/- SE, n = 5). Scatchard analysis showed that MOPC-315 cells had 40,733 +/- 16,050 (mean +/- SE) binding sites for SOM per cell. The characteristics of the interactions of SOM with MOPC-315 cells suggest a specific receptor-mediated mechanism whereby this neuropeptide may modulate lymphocyte function.

Animals↗
PubMed1988

Seasonal variation in non-specific bronchial reactivity: a study of wheat workers with a history of wheat associated asthma.

To investigate seasonal variation in non-specific bronchial reactivity in wheat workers, we carried out histamine inhalation tests in 29 workers (28 of them men) from a small farming community with symptoms of wheat associated asthma before, during and after the 1983-4 Australian wheat harvest season. Four were cigarette smokers, and the age range was 12-54 (mean (SD) 30 (10)) years. Twenty eight subjects were atopic (one positive skinprick test result in tests with 10 common antigens), 60% reacting to house dust mite and all to at least one of eight wheat antigens. Baseline spirometry gave normal results (mean FVC1 90% (SD 8%) predicted; FVC 91% (7%) predicted). Bronchial reactivity was tested by the method of Yan et al. The cumulative doses of histamine acid phosphate (up to 3.91 mumol) that caused a fall of 20% from baseline in FEV1 was determined (PD20) and expressed as the geometric mean. In the low exposure season, May 1983, nine subjects had a PD20 (mean 1.2, range 0.3-3.9 mumol). The number rose to 19 in the summer harvest season, December 1983 (mean 0.8, range 0.07-3.9 mumol) and returned to nine in the subsequent winter, July 1984 (mean 1.8, range 0.4-3.9 mumol). The change in the number of subjects with a PD20 was significant (p less than 0.01). Four additional subjects probably had increased bronchial reactivity in the harvest season: in two the post-saline FEV1 was too unstable to give them histamine challenge and in two the challenge was inadvertently discontinued prematurely. Baseline FEV1 and FVC fell by 8% between the first and second studies (p less than 0.001); values were intermediate in the third study (FEV1 3.74, 3.44, and 3.57; FVC 4.66, 4.28, and 4.41 litres respectively). Linear modelling analysis of log PD20, season, FEV1, FVC, age, seasonality of asthma symptoms and skin test data indicated that the harvest season was the only significant determinant of variation in log PD20. It is concluded that in these wheat workers there is a seasonal variation in bronchial reactivity that may reflect a response to allergens associated with grain.

Adolescent↗
PubMed1988

Antigen-induced contraction of jejunal smooth muscle in the sensitized rat.

We examined contractility of longitudinal muscle strips of jejunum from control rats and rats infected 34-85 days previously with Trichinella spiralis. Antigen prepared from T. spiralis larvae contracted muscle from previously infected but not control rats. Contraction was specific for the sensitizing agent because antigen from Nippostrongylus brasiliensis did not induce contraction. Contraction was resistant to atropine or tetrodotoxin but was inhibited by the 5-hydroxytryptamine (5-HT) antagonist cyproheptadine and by 5-HT desensitization. Neither histamine antagonists, diphenhydramine (H1-receptor antagonist) or ranitidine (H2-receptor antagonist), nor indomethacin, a prostaglandin synthase inhibitor, influenced the antigen response. In Trichinella-infected rats there was a significant increase in mast cell number in the muscle layers, and the contraction induced by T. spiralis antigen was inhibited by the mast cell stabilizer doxantrazole. In addition, anti-rat immunoglobulin E serum, compound 48/80, and concanavalin A each contracted muscles from rats previously infected with T. spiralis. These results are consistent with the hypothesis that T. spiralis infection leads to mast cell proliferation in the muscle layers and that subsequent exposure to antigen results in mast cell degranulation, 5-HT release, and contraction of smooth muscle.

Animals↗
PubMed1988

In vivo immunomodulation by the neuropeptide substance P.

Many experiments have demonstrated that the nervous and immune systems interact in a bidirectional fashion. Neuropeptides, including substance P, have been shown to modulate lymphocyte DNA, RNA and immunoglobulin synthesis in vitro and to play a role in inflammatory and hypersensitivity disease states. However, the role of substance P as an immunomodulator in vivo is uncertain and there is only indirect evidence of this effect obtained in vitro. Therefore, we have assessed the effect of substance in vivo on DNA and immunoglobulin synthesis by murine splenic and Peyer's patch lymphocytes after the continuous administration via a miniosmotic pump of substance P in vivo. Substance P administered in this fashion increased cell proliferation of lymphocytes isolated from both organs. Immunoglobulin synthesis was also increased and in a relatively isotype-specific manner. IgA synthesis was most affected, IgM synthesis less so and IgG synthesis was not changed significantly. These effects of substance P on lymphocytes in vivo are similar to its effects on cell proliferation and immunoglobulin synthesis when cells are exposed to this peptide in vitro. These results provide direct evidence that neuropeptides (substance P) may modulate lymphocyte function in vivo and that neuropeptides should be incorporated into the conceptual framework of immune regulation.

Animals↗