Free radical lipid peroxidation through expired ethane and pentane. An improved method.
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Breath Tests↗
Biomedical subjects
A Conti
Publications and source records attributed to A Conti.
Ibopamine in congestive heart failure refractory to digitalis, diuretics, and captopril.
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Aged↗
The preparation and physicochemical characterization of an injectable form of reconstituted, glutaraldehyde cross-linked, bovine corium collagen.
Pepsin-solubilized bovine corium collagen was purified, reconstituted, and treated with various levels of glutaraldehyde. Treatment of suspensions of fibrillar collagen with low concentrations of glutaraldehyde appeared to have little effect on the gross morphology of fibrils, as judged by electron microscopy, but did have a significant impact on their physicochemical stability. Fibrillar collagen treated with glutaraldehyde at a concentration equal to or greater than 0.0075% demonstrated significant decreases in neutral solubility at elevated temperatures as compared to noncross-linked controls. Differential scanning calorimetry provided a convenient and quantitative means to correlate increases in melting temperature with increases in glutaraldehyde treatment concentration. Fibrillar collagen cross-linked with glutaraldehyde concentrations as low as 0.0075% demonstrated a significantly greater resistance to proteolytic degradation than did noncross-linked fibrillar collagen samples. The residual, extractable aldehyde content of such preparations was between 1 and 3 ppm. Rheological measurements on such cross-linked suspensions demonstrated that they were non-Newtonian, shear-thinning fluids, and that they were two- to threefold more viscous than corresponding preparations of noncross-linked collagen.
Amino Acids↗
Histamine release by free radicals: paracetamol-induced histamine release from rat peritoneal mast cells after in vitro activation by monooxygenase.
The incubation of paracetamol with isolated rat serosal mast cells evokes the release of histamine only in the presence of (S10) liver microsomes obtained from PCB or phenobarbital treated rats. The release of histamine was not accompanied by a leakage of lactate dehydrogenase and was blocked by the antioxidant alpha-tocopherol and by D-mannitol, an hydroxyl free radicals scavenger. The data are consistent with the metabolic oxidation of paracetamol in the generation of reactive intermediates capable of activating the sequential exocytosis.
Acetaminophen↗
Role of the pineal gland in immunity. Circadian synthesis and release of melatonin modulates the antibody response and antagonizes the immunosuppressive effect of corticosterone.
Inhibition of synthesis of the pineal neurohormone melatonin (MEL) in mice, by administration of propranolol (PRO) in the evening, and daily injections of p-chlorophenylalanine (PCPA), resulted in a significant depression of the primary antibody response to sheep red blood cells (SRBC). Spleen cells from these mice showed a reduced reactivity against antigens in the autologous mixed lymphocyte reaction (AMLR). In contrast, alloreactivity remained normal. Reconstitution of the night-time peak of plasma MEL by evening injections to the mice completely reversed the suppression of the humoral response and the AMLR. MEL administration was able to antagonize the depression of antibody production induced by corticosterone in vivo. These results suggest that the pineal gland has important immunomodulatory functions through its cyclic, circadian release of MEL.
Animals↗
Preparation of [3H]collagen for studies of the biologic fate of xenogenic collagen implants in vivo.
Reduction of a commercially available, pepsin-solubilized, bovine dermal collagen (Vitrogen 100) with sodium [3H]borohydride provided radiolabeled collagen preparations with specific activities ranging from 7.1-12.0 muCi/mg collagen. These specific activities were 2-3 times greater than those obtained by reduction of intact rat tail tendon collagen under similar conditions. The alpha, beta, and higher aggregate components of type I collagen were radiolabeled as well as the alpha component of a small amount of type III collagen present in the samples. Fractionation of cyanogen bromide peptides showed that alpha 1(I)CB7, alpha 1(I)CB8, and alpha 2(I)CB3,5 were the predominant peptides labeled by this procedure. Amino acid analysis indicated that the majority of the radioactivity was in reducible cross-links, precursors of these cross-links, and in hexosyllysine residues. Reconstitution experiments comparing this radiolabeled collagen with nonlabeled collagen showed them to be indistinguishable. Bacterial collagenase digestion of this reconstituted fibrillar collagen in both a lightly cross-linked (glutaraldehyde 0.0075%) and noncross-linked form provided evidence that digestion of labeled and nonlabeled collagens proceeded at similar rates. Thus, labeling did not change the properties of the collagen. Cross-linking made the preparation refractory to proteolytic degradation. Injection of fibrillar collagen preparations, spiked with radiolabeled collagen, into the guinea pig dermis followed by quantitation of the amount of radioactivity recovered from implant sites as a function of time, indicated that the lightly cross-linked samples also were more resistant to degradation in vivo than the noncross-linked preparation. The half-life of noncross-linked collagen was about 4 days while that of the cross-linked collagen was about 25 days. These degradation rates were much faster than observed for similar, nonlabeled samples injected into the dermis of humans, presumably due to a higher metabolic activity in the guinea pig dermis.
Animals↗
Pig beta-lactoglobulin I (Sus scrofa domestica, Artiodactyla). The primary structure of the major component.
beta-Lactoglobulins from pooled milk (Sus scrofa domestica) are isolated and characterized. The complete primary structure of the major beta-lactoglobulin component I is presented. The amino-acid sequence was elucidated by automated Edman degradation of tryptic peptides and cyanogen bromide cleavage products in a liquid phase sequencer. The tryptic and cyanogen bromide peptides were separated by reverse-phase (RP-2) or size exclusion (TSK 2000 SW) high performance liquid chromatography. Pig beta-lactoglobulin is composed of only 159 amino acids in contrast to other beta-lactoglobulins which contain 162 or 166 amino acids. Sequence alignment with previously sequenced beta-lactoglobulins was obtained by introducing two gaps at positions 115 and 151-152. Thus bovine beta-lactoglobulin A reveals 62 amino-acid substitutions. The phylogenetic distance from horse beta-lactoglobulin I and II is indicated by 49.4% and 62% amino-acid exchanges, respectively. Pig beta-lactoglobulin is a mixture of two chains with Gln or Thr at position 119. The free thiol group is localized at position 59. The structural and functional aspects of beta-lactoglobulins and its role in vitamin A (retinol) transport are discussed.
Amino Acid Sequence↗
Inhibition of lactation by a long-acting bromocriptine.
A long-acting form of bromocriptine, a prolactin (PRL) secretion inhibitor, was administered to 122 postpartum women in single intramuscular injections of 20 (N = 24), 30 (N = 22), 40 (N = 46), and 50 mg (N = 30). In 91 women the substance was administered immediately after delivery to prevent galactopoiesis and in the remaining 31 women to inhibit established lactation. Effectiveness was estimated by the absence of breast engorgement and of milk secretion. Successful prevention or inhibition of lactation was highest among women receiving 50 mg bromocriptine (97%), and comparison between dosages revealed a close linear dose-response relationship (r = 0.98). Persistent and significant (P less than .001) PRL inhibition could be recorded for up to 22 days in successfully treated puerperas in comparison with 12 normally breast-feeding women who served as control subjects. No significant side effects or local reactions were recorded. Eleven of 46 postpartum women receiving 20 or 30 mg bromocriptine experienced onset of milk secretion or lactation rebound, and responded to oral administration of the drug. The presence of milk was associated with plasma PRL concentrations persistently above 25 ng/mL in all of them, whereas nine women in the same dosage range in whom lactation suppression was effective exhibited values below this limit. Dose-response data allow the establishment of a putative PRL threshold for induction of milk secretion of about 25 ng/mL. Maintenance of plasma PRL values below this limit prevents lactogenesis and inhibits lactopoiesis.
Bromocriptine↗
[Validity of the granulocyte aggregation test for the evaluation of complement activation in the adult respiratory distress syndrome].
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Cell Aggregation↗
Hemodynamic and electrocardiographic effects of fructose-1,6-diphosphate in acute myocardial infarction.
Acute hemodynamic and electrocardiographic effects of fructose-1,6-diphosphate (FDP), an agent that is supposed to restore anaerobic glycolytic flux in the ischemic myocardium, were studied in 40 patients with acute myocardial infarction who were grouped into 4 subsets: subset 1, normal (15 mm Hg or less) pulmonary artery (PA) wedge pressure and normal (35 g-m/m2 or greater) left ventricular (LV) stroke work index; subset 2, elevated (more than 15 mm Hg) PA wedge pressure and normal LV stroke work index; subset 3, normal PA wedge pressure and reduced (less than 35 g-m/m2) LV stroke work index; subset 4, elevated PA wedge pressure and LV stroke work index moderately reduced to a range between 16 and 34 g-m/m2. Patients were randomized into an FDP (250 mg/kg body weight in isotonic saline solution intravenously in 20 minutes) and into a placebo group. Each subset contained 5 FDP- and 5 placebo-treated patients. After basal measurements, hemodynamic measurements were reassessed at 60, 90 and 120 minutes from the infusions, while a standard 12-lead electrocardiogram was recorded in the basal state and 120 minutes after infusion. Nonsignificant hemodynamic change was observed in the placebo subsets, and FDP failed to exert any effect in subsets 1, 2 and 3. A 24% (p less than 0.02) increase in cardiac index occurred 60 minutes after FDP in subset 4. LV stroke work index also increased, while PA wedge pressure remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Immunological modulation of cholinergic histamine release in isolated rat mast cells.
Isolated purified rat mast cells release histamine when exposed to acetylcholine according to different patterns of sensitivity. The degree of histamine release is correlated with the levels of reaginic antibodies presumably bound to the mast cell membrane. In fact, mast cells passively sensitized with mouse myeloma IgE against egg albumin or DNP2-lysine, react to acetylcholine with a release of histamine, which is proportional to the IgE concentration in the incubation medium. The histamine release induced by acetylcholine is due to the stimulation of a muscarinic receptor. Accordingly, acetylthiocholine is unable to evoke histamine release and preincubation of sensitized cells with atropine fully inhibits the cholinergic histamine release. The histamine release evoked by acetylcholine is potentiated by the exposure of sensitized cells to the specific antigen. The present results suggest that sensitization of mast cells is a crucial factor in modulating their sensitivity to acetylcholine.
Acetylcholine↗
Hemodynamic effects of digoxin in acute myocardial infarction in man: a randomized controlled trial.
Hemodynamic effects of digoxin in acute myocardial infarction (AMI) have been acknowledged to depend on the basal cardiocirculatory state. In the present study, the effects of digoxin in patients with AMI were evaluated in four hemodynamic subsets, based on the relationship between mean pulmonary capillary wedge pressure (PCWP, in mm Hg) and left ventricular stroke work index (LVSWI, in g-m/m2): subset 1: normal (less than or equal to 15 mm Hg) PCWP and normal (greater than or equal to 35 g-m/m2) LVSWI; subset 2: elevated (greater than 15 mm Hg) PCWP and normal LVSWI; subset 3: reduced (less than 35 g-m/m2) LVSWI and normal PCWP; and subset 4: elevated PCWP and LVSWI moderately reduced to a range between 16 and 34 g-m/m2. Forty patients were admitted to the study and were randomly assigned to one of two groups in each subset: control group (19 patients) and treated group (21 patients). Five patients were randomized into each of the subsets 2, 3, and 4 in both the control and treated groups, while in subset 1 there were four control and six digoxin-treated patients. Control patients were administered a placebo saline solution and digoxin-treated patients received 0.50 mg of the drug intravenously in 20 minutes. The effects of the placebo and of the drug were evaluated at 30, 60, and 90 minutes from the end of the infusion. Hemodynamic data did not vary in the control group, and digoxin did not exert any relevant effect in subsets 1 and 2. After drug infusion, cardiac index (Cl, in L/min/m2) significantly increased in subset 3 patients.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Collagen fibrillogenesis in vitro: a characterization of fibril quality as a function of assembly conditions.
Pepsin-solubilized bovine corium collagen was reconstituted by rapid neutralization in dilute phosphate buffer at temperatures ranging from 10 degrees C-25 degrees C. The resultant fibrils were harvested by centrifugation and resuspended in physiological buffer to a constant protein concentration. The optical density of such suspensions, measured at 410 nm in a 1 mm path length cuvette, exhibited a strong inverse correlation with temperature of fibrillogenesis. The absorbance values of fibrillar suspensions prepared from intact collagen were greater than those observed with suspensions prepared from pepsin-solubilized collagen under similar conditions and demonstrated a reduced dependence on temperature of fibril assembly. The nature of the variation in opacity of fibrillar suspensions prepared from pepsin-solubilized material was further investigated using transmission electron microscopy, trypsin sensitivity, SDS gel electrophoresis and polarimetry. Reconstitution conditions that favored more rapid precipitation (e.g., higher incubation temperatures) tended to produce fibril suspensions of lower opacity (translucent). These translucent suspensions exhibited fibrils that were small in diameter when compared to fibril suspensions of higher opacity. Translucent preparations also contained higher levels of a trypsin sensitive, early melting component and displayed a higher proportion of peptides migrating faster than alpha 2(I) on SDS polyacrylamide gels. Collagen preparations depleted of the early melting component continued to demonstrate the correlation between increased temperature and decreased fibrillar opacity, suggesting that the two phenomena were independent. It is proposed that the unstable components are nicked or shortened collagen helices, presumably generated by pepsinization or the action of endogenous proteases of the bovine corium, which are differentially incorporated into fibrils depending on the conditions of fibril assembly.
Animals↗
Mast cell heterogeneity in response to cholinergic stimulation.
Mast cell heterogeneity in response to acetylcholine has been evidentiated by the virtual lack of sensitivity or by the full reaction to nanomolar concentrations of acetylcholine, observed in samples of serosal mast cells isolated from the same animal species. The incubation with IgE of isolated rat mast cells renders the originally heterogeneous response homogeneous, the release of histamine evoked by acetylcholine being proportional to the IgE concentration. The histamine release induced by acetylcholine is due to the activation of muscarinic receptors, since it is blocked by atropine, not reproduced by acetylthiocholine and potentiated by exposure of the cells to the specific antigen.
Acetylcholine↗
Bromocriptine treatment of microprolactinomas: evidence of stable prolactin decrease after drug withdrawal.
Thirty-six women with PRL-secreting pituitary microadenomas [mean PRL, 114 +/- 12.5 (+/- SE) ng/ml] were treated with bromocriptine (BRC; 2.5-10 mg/day) for 12 months. During BRC treatment, serum PRL decreased in all patients. After termination of treatment, mean serum PRL levels, evaluated at 15, 30, and 45 days, were significantly decreased (-41.6%, -43.0%, and -40.2%, respectively) compared to pretreatment values. The patients were arbitrarily divided into 3 groups: 12 responders, in whom the PRL persistent posttreatment decrease was greater than 50%, 8 hyporesponders, in whom the PRL decrease was between 30% and 50%, and 16 nonresponders with absent or negligible PRL decrease. Four patients had normal PRL levels and clinical remission for 14-30 months after BRC withdrawal. In 18 women, BRC treatment was repeated for another 12 months. After termination of treatment, 11 patients were responders, 1 was a hyporesponder, and 6 were nonresponders. Four of these 18 patients still had normal PRL levels 8-28 months after drug discontinuation. The responses of PRL to TRH and domperidone were compared before and after termination of treatment at 30 and 45 days, respectively. Both mean peak values of PRL and absolute increases after TRH treatment were similar before and after BRC administration; however, a PRL response to TRH was present in 15% of 26 patients before treatment and in 42% after treatment. The mean peak values after domperidone were similar before and after BRC treatment, but the absolute increase over the basal value was much higher after BRC; PRL response to domperidone was present in 16% of 19 patients before BRC treatment and in 74% after BRC. These data suggest that BRC is effective in the treatment of some microprolactinomas; BRC effectiveness improves after prolonged periods of administration. The variations in PRL responses to TRH and domperidone suggest profound modification of PRL secretion after BRC treatment.
Adenoma↗
Homology between the primary structures of beta-lactoglobulins and human retinol-binding protein: evidence for a similar biological function?
Two types of beta-lactoglobulins were identified and isolated from horse colostrum: beta-1g I and beta-1g II. The amino-acid sequence of some tryptic peptides from the new monomeric beta-lactoglobulin II was determined and aligned to the other beta-lactoglobulins of known sequence and to the human plasma retinol-binding protein. The comparison of the primary structures of beta-lactoglobulins and human retinol-binding protein shows an unexpectedly high homology of 25%. We found 37 identities among 149 possible homologous residues. Among them is a tryptophan residue at position 19 of beta-lg which might represent the binding site of beta-ionone. These data suggest a common origin of beta-lactoglobulin and human retinol-binding protein and imply that beta-lactoglobulins may be involved in the metabolism of retinol.
Amino Acid Sequence↗
The amino-acid sequence of beta-lactoglobulin II from horse colostrum (Equus caballus, Perissodactyla): beta-lactoglobulins are retinol-binding proteins.
beta-Lactoglobulin isolated from horse colostrum is heterogeneous and contains two components: beta-lactoglobulin I and beta-lactoglobulin II. These two proteins are monomeric and show differences in their electrophoretic mobilities, chain lengths and primary structures. The complete amino-acid sequence of beta-lactoglobulin II was determined by automated Edman degradation of the intact protein and of the peptides derived from these by digestion with trypsin or chymotrypsin and by chemical cleavage with cyanogen bromide. Unlike other beta-lactoglobulins which contain 162 amino acids, horse beta-lactoglobulin II is unique in that it contains 166 amino acids. The additional four amino acids represent an insertion between positions 116 and 117 of other beta-lactoglobulins so far sequenced, including horse beta-lactoglobulin I. Sequence comparison of beta-lactoglobulins I and II from horse colostrum reveals 48 amino acid substitutions (30%). Such a diversity between members of the beta-lactoglobulin gene family has not been encountered before. Sequence comparison with bovine beta-lactoglobulin A shows 85 amino acid replacements accounting for 53% of the residues. The structural homology with human retinol-binding protein may reveal similar biological functions and clues to the origin of milk proteins.
Amino Acid Sequence↗
[Ventricular fibrillation in the initial phase of acute myocardial infarct].
In order to determinate the incidence, predictivity and prognosis of ventricular fibrillation in the early phase of acute myocardial infarction a series of 301 patients with acute myocardial infarction consecutively assisted by the Mobile Coronary Care Unit of Florence was analyzed. 151 patients (50.2%) received intensive care within 2 hours from the onset of the symptoms, 75 patients (24.9%) received intensive care between the second and sixth hour. 38 patients (12.6%) had at least one episode of ventricular fibrillation. 30% of the episodes of ventricular fibrillation happened within 1 hours from the onset of the symptoms, 47.4% within 2 hours, 74% within 6 hours. Serious arrhythmias complicated the early phase of acute myocardial infarction, but only sinus bradycardia seems to have a significant predicativity of ventricular fibrillation (P less than 0.05). We found that hospital survival resuscitated patients is strictly related to the time between early symptoms and the episode of ventricular fibrillation: 91% of the patients with ventricular fibrillation within 1 hour were discharged alive from hospital, 71% of those with ventricular fibrillation within 6 hours, 20% of those with ventricular fibrillation beyond 6 hours (P less than 0.01). The high rate and the favourable prognosis of ventricular fibrillation in the early phase of acute myocardial infarction must lead to a widespread implementation of rapid response emergency care systems away from hospital.
Humans↗