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Biomedical subjects

A Bruni

Publications and source records attributed to A Bruni.

At least 91 records · Page 5Linked to original sources
PubMed1985

Serine phospholipids as endocoids.

Unusual phospholipid effects may occur when their distribution in the membrane is altered or when uncontrolled metabolic reactions yield elevated concentrations of their short lived derivatives. Serine phospholipids are normally buried in the internal side of plasma membrane. Upon exposure to the extracellular environment they elicit a response from selected cell populations. The interaction between these phospholipids and neuroactive compounds in rat peritoneal mast cells may indicate that serine phospholipids have a role in the nervous system during development.

Animals↗
PubMed1984

Synergistic effect of phosphatidylserine with gamma-aminobutyric acid in antagonizing the isoniazid-induced convulsions in mice.

The influence of phosphatidylserine (PS) on the isoniazid-induced convulsions has been studied in mice. Sonicated dispersions of this phospholipid given intravenously do not show anticonvulsant activity but they do so when gamma-aminobutyric acid (GABA) is simultaneously injected. GABA alone is inactive. The synergism between PS and GABA is influenced by the structure of the phospholipid liposomes. In contrast to multilamellar vesicles, oligolamellar vesicles are active. Under these conditions the effect shows head group specificity, in that the neutral phosphatidylcholine (PC) or the acidic phosphatidylinositol (PI) are inactive, either in the presence or in the absence of GABA. Lysophosphatidylserine (lysoPS), the deacylated PS derivative, shows increased efficacy as an isoniazid antagonist in the presence of GABA, and has anticonvulsant activity also in the absence of GABA. Other lysophospholipids are inactive. It is suggested that PS, after its metabolic conversion to lysoPS, enhances the anticonvulsant effect of GABA.

Animals↗
PubMed1984

Modulation of lysophosphatidylserine-dependent histamine release.

Apomorphine (2-30 microM) inhibits lysophosphatidyl-serine-dependent histamine release in rat and mouse peritoneal mast cells. The drug-induced inhibition is influenced by the concentration of lysophosphatidylserine. Log concentration-response curves show a surmountable type of antagonism between the two compounds.

Animals↗
PubMed1984

Local effects of lysophosphatidylserine in rats.

To study the inflammatory properties of lysophosphatidylserine (a phospholipid acting as a histamine releaser), rats were subjected to local treatment with this compound. In the paw a rapid and dose-dependent edematous reaction occurred within 30-60 min (ED50 2.5 micrograms/rat). The effect was dependent on the intact configuration of serine head group since lysophosphatidylcholine, lysophosphatidylethanolamine, lysophosphatidic acid and N-acetimidyl-lysophosphatidylserine were uneffective. Indomethacin produced a weak inhibition but chlorpheniramine and cyproheptadine inhibited 50 and 70%, respectively. Consistently, the histamine stores of the paw were found to be decreased at the end of the lysophosphatidylserine effect. Increase in vascular permeability was observed also after the injection of lysophosphatidylserine into the dorsal skin and pleural cavity although the phospholipid was less effective in these regions. The fluid extravasation in the pleural cavity was 75% prevented by cyproheptadine. Parallel in vitro experiments showed that the effect of lysophosphatidylserine on isolated pleural and peritoneal mast cells is increased when a leukocyte lysate was also added. After centrifugation the activity was retained in the insoluble fraction. It is concluded that lysophosphatidylserine, injected locally, elicits an inflammatory reaction mediated by the components of mast cell granulus. The response may be amplified by the migration of other inflammatory cells into the exudate.

Animals↗
PubMed1984

Different responses of rodent mast cells to lysophosphatidylserine.

The lysophosphatidylserine-induced activation of mast cells has been studied in preparations obtained from different rodents. In mouse and gerbil peritoneal mast cells lysophosphatidylserine behaves as an agonist, inducing noncytotoxic histamine release at 0.2-8 microM. In rat peritoneal and pleural mast cells lysophosphatidylserine is ineffective, but the histamine-releasing activity becomes manifest upon the addition of suboptimal concentrations of other mast cell activators. The common structure-activity relationship shows the link between these effects of lysophosphatidylserine but the calcium requirement indicates differences in the mechanism of action. Histamine release in mouse mast cells is independent of external calcium. Thus, lysophosphatidylserine induces mobilization of endogenous calcium stores in these cells. By contrast, histamine release in gerbil and rat mast cells is dependent on the addition of external calcium indicating that the phospholipid promotes calcium influx. While in gerbil mast cells calcium influx is promoted by lysophosphatidylserine alone, in rat it requires the combined action of the phospholipid and other mast cell agonists. Differently from lysophosphatidylserine, compound 48/80 elicits histamine release in rat and gerbil mast cells. Mouse mast cells are unaffected. Thus, gerbil mast cells are the only preparation in which the action of these two agonists can be observed simultaneously.

Animals↗
PubMed1984

Lysophosphatidylserine as histamine releaser in mice and rats.

Lysophosphatidylserine is a specific inducer of histamine release in isolated mast cells. To determine whether a similar effect is manifest in vivo, the phospholipid was injected (1-5 mg/kg i.v.) into mice and rats. A dose-dependent rise in blood histamine was observed in both animals. The several-fold increase in blood histamine occurred in the first minutes and was followed by a slower decline toward normal values. A second dose of lysophosphatidylserine was without effect. Systemic manifestations (depression, hypothermia, hypotension) were associated with the increased blood histamine level. When the tissue histamine stores accessible to lysophosphatidylserine were previously decreased by repeated phospholipid injections, no systemic symptoms occurred. Mobilization of carbohydrate reserves was also manifest during the action of lysophosphatidylserine. Prior treatment with compound 48/80 induced sustained refractoriness to lysophosphatidylserine. Structure-activity relationship demonstrated that the property to induce histamine release was linked to the structure of serine head group. Thus, other natural phospholipids or lysophospholipids were inactive. It is concluded that in analogy with the effect seen in vitro lysophosphatidylserine produces in vivo release of mast cell histamine.

Adrenalectomy↗
PubMed1984

[Granulocyte function in Duchenne's progressive muscular dystrophy].

We studied the in vitro function of polymorphonuclear leukocytes in 14 patients affected by Duchenne muscular dystrophy, aged 2-14 years, especially the chemotaxis and the bactericidal activity. The chemotaxis appeared significantly reduced, while the bactericidal activity was sometimes reduced, sometimes increased. In this disease the polymorphonuclear leukocytes seems to have a reduced capacity of movement; probably this phenomenon is connected with an alteration of the muscular cellular apparatus, which perhaps is related with an electrolytic intercellular inequality. These findings are consistent with the definition of Duchenne muscular dystrophy as a systemic disease of the membrane with alterations not only of striped muscular fibers, but of various cells and tissues.

Adolescent↗
PubMed1983

A histofluorescent procedure for identifying marijuana cannabinoids.

A rapid and reliable fluorescence procedure is described as a test for the microscopical identification of the glandular hairs of Cannabis sativa. The proposed method, designated as the IFIM test (induced fluorescence identification for marijuana test), is based on the induction of a red fluorescence in cannabinoids by a hot clearing solution. The results, compared to those obtained by the classical RIM test, offer the possibility of more satisfactory identification of cannabis, hashish or marijuana in suspected samples.

Cannabinoids↗
PubMed1981

Regulation of phospholipid-ATPase complex interaction by the adenine nucleotide carrier.

(1) The effect of phospholipids on a preparation containing the ATPase complex and the adenine nucleotide carrier is studied in the presence of ligands known to affect the conformation of these components of the mitochondrial inner membrane. (2) When ATPase activity is abolished by phospholipid depletion, the reactivation induced by phosphatidylcholine is prevented by the simultaneous addition of ATP. ADP partially reproduces the ATP effect. AMP, GTP, UTP, and Pi are ineffective. (3) The influence of ATP is associated with reduced phospholipid binding to the membrane fragments and is reversible. The ATP effect on reconstitution is not manifest when phosphatidylcholine is added together with negatively charged phospholipids. (4) Carboxyatractyloside does not modify the phospholipid-ATPase complex interaction but bongkrekic acid is as effective as ATP. In the presence of ADP, the influence of bongkrekic acid is considerably increased. (5) It is concluded that the binding of ATP to the adenine nucleotide carrier enables the complex to select between the charged and uncharged phospholipids. As a result of the carrier conformational change, the ATPase complex is induced to prefer a negatively charged phospholipid environment.

Adenosine Triphosphatases↗
PubMed1980

Phospholipid-dependent assembly of mitochondrial ATPase complex.

1. Phosphatidylcholines of different acyl-chain composition and a preparation of ATPase complex depleted of phospholipids have been employed in order to evaluate the contribution of lipid bilayer to the assembly of this multi-subunit component of mitochondrial membrane. 2. At the minimal requirement for bilayer assembly (dinonanoylphosphatidylcholine, mixtures of lysophosphatidylcholine and phosphatidylcholine), fragments with oligomycin-insensitive ATPase activity are reconstituted. Conformational changes with dislocation of ATPase complex subunits may explain these results. 3. At increased strength of acyl-chain interaction (dilauroylphosphatidylcholine and higher homologues), the damage to the ATPase complex is prevented but this is not sufficient to achieve functional restoration. Bilayers with a tendency to coalesce and fuse aggregate in large amounts with the complex and yield low ATPase reactivation. Bilayers of high stability yield complexes with physiological content of phospholipids and efficient ATPase activity. Transition between these two possibilities is found at sixteen carbon acyl-chains. Only at this chain length does the cholate dialysis procedure of reconstitution become feasible. 4. It is concluded that a minimum of 16 carbon atoms in each chain are required to organize a bilayer structurable to maintain the ATPase complex conformation and to sustain the transmembrane position of the whole assembly.

Adenosine Triphosphatases↗
PubMed1980

Two rapid fluorescence procedures for the detection of some thio pungent compounds in plant tissues.

Two rapid flourescence procedures are described for detecting sulphydryl, disulphide and isothiocyanate groups of scented and pungent principles present in the vacuolar sap of onion, garlic and cabbage. To localize compounds containing sulphydryl groups, fresh or fixed frozen sections of the plants were treated with mercurochrome. After the fluorochromization, strongly-positive sulphydryl sites emitted an intense orange-red fluorescence, while weakly-positive sites emitted a distinctive red-brown fluorescence. Disulphide groups were detected by first reducing with thioglycolic acid to thiol groups before treating with mercurochrome. To effect isothiocyanate localization, frozen sections were exposed to ammonia: isothiocyanates were converted to thioureas and the engendered amino groups were revealed with fluorescamine.

Disulfides↗
PubMed1980

Arteriograms of the palatine arteries in normal and cleft palate dogs.

Arteriography was used to study the arterial distribution of the hard and soft palate in dogs with and without cleft palate. Selective catheterization of the maxillary arteries produced arteriograms of the palatine arteries. Surgical exposure of the left common carotid artery or the right femoral artery was used for entry into the arterial system. The control dogs demonstrated a normal number of foramina (one on each side) with cross communication of the terminal arteries. The presence of additional foramina on the left side of the cleft as compared with the right side indicates the possibility of greater vascularity unilaterally. These findings may be of clinical significance.

Angiography↗
PubMed1980

Lysophosphatidylserine-induced release of intra-cellular amines in mice.

In the presence of mouse plasma, lysophosphatidylserine stimulates histamine secretion from isolated mast cells. The extensive modification of carbohydrate metabolism produced by lysophosphatidylserine in mice was largely prevented by the antihistaminic drug, pyrilamine. However, to prevent completely the change in carbohydrate metabolism induced by lysophosphatidylserine the administration of an antihistamine and an adrenoceptor antagonist was required. It is concluded that the effect of lysophosphatidylserine in mice is due to release of intracellular amines. Histamine and catecholamines are involved.

Animals↗
PubMed1979

F1-ATPase from different submitochondrial particles.

1. F1-ATPase has been extracted by the diphosphatidylglycerol procedure from mitochondrial ATPase complexes that differ in ATPase activity, cold stability, ATPase inhibitor and magnesium content. 2. The ATPase activity of the isolated enzymes was dependent upon the activity of the original particles. In this respect, F1-ATPase extracted from submitochondrial particles prepared in ammonia (pH 9.2) and filtered through Sephadex G-50 was comparable to the enzyme purified by conventional procedures (Horstman, L.L. and Racker, E. (1970) J. Biol. Chem. 245, 1336--1344), whereas F1-ATPase extracted from submitochondrial particles prepared in the presence of magnesium and ATP at neutral pH was similar to factor A (Andreoli, T.E., Lam, K.W. and Sanadi, D.R. (1965) J. Biol. Chem. 240, 2644--2653). 3. No systematic relationship has been found in these F1-ATPase preparations between their ATPase inhibitor content and ATPase activity. Rather, a relationship has been observed between this activity and the efficiency of the ATPase inhibitor-F1-ATPase association within the membrane. 4. It is concluded that the ATPase activity of isolated F1-ATPase reflects the properties of original ATPase complex provided a rapid and not denaturing procedure of isolation is employed.

Adenosine Triphosphatases↗