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Biomedical subjects

E Boschetti

Publications and source records attributed to E Boschetti.

At least 73 records · Page 4Linked to original sources

Round table on antiasthmatic drugs; beta-agonists and theophylline. Workshop on pathogenesis and therapy of bronchial asthma Cortina d'Ampezzo/1-4 April, 1987.

Beta 2-agonists and theophylline compounds are first line drugs and are extensively used in the treatment of acute bronchial asthma. Beta 2-agonists are continuously expanding as a class of drugs. Recent research has increased the available knowledge of their cardiovascular and metabolic effects. Cardiovascular effects might be due to direct stimulation of beta 2-receptors sited in the atrial muscle. Metabolic effects (i.e. increase in blood glucose, insulin and non-esterified fatty acid (NEFA), decrease in plasma potassium) are, at least partly, a consequence of direct or reflex stimulation. Despite recent progress, slow-release theophylline compounds remain a basic approach to asthma management. Future progress in this field will probably be concerned with a more complete knowledge of 'ultra-slow' theophylline compounds (level of the plasma concentration fluctuation and patient compliance) and more complete results regarding the influence exerted by food (and gastric pH) on the rate and extent of absorption.

Adrenergic beta-Agonists↗

p-Benzylthiocarbamoyl-aspartyl-daunorubicin-substituted polytrisacryl. A new drug acid-labile arm-carrier conjugate.

A new type of drug acid-labile arm-carrier is described. A hydrophilic polymer [polytrisacryl, or poly(acryloyl 2-amido-2-hydroxymethyl-1,3-propanediol)], used as a model, is substituted with p-nitrobenzyl groups. The nitrobenzyl groups are reduced to aminobenzyl and transformed into benzylisothiocyanate groups which are allowed to react with aminoacyl daunorubicin. The excess of benzylisothiocyanate is transformed into benzylthiocarbamoyl N-methyl glucamine. A conjugate containing benzylthiocarbamoyl-aspartyl daunorubicin is stable at neutral pH, and releases free daunorubicin when it is exposed to pH 5 or below. This conjugate is about 200-fold less toxic than free daunorubicin, on a molecular basis, when it is added to the medium of Lewis lung carcinoma (3LL) cells in culture.

Acrylates↗

Application of chromatographic methods to the analysis of macrophage factors induced by Nocardia opaca cell walls.

Cell walls from Nocardia opaca induce the production of mitogenic factors by mouse peritoneal macrophages in vitro. These factors stimulate thymocytes from C3H/HeJ mice. Supernatants of peritoneal cell culture exhibiting this activity were fractionated by chromatographic procedures such as gel filtration and metal chelate affinity chromatography and the biological activities assayed. These fractionation studies indicate that several biologically active products occur in the supernatant. Four factors monokines (M) with different apparent molecular masses M1 (100,000), M2 (50,000), M3 (16,000) and M4 (7000) were obtained, one of which (M3) was identical to interleukin 1 (IL1). Several of the biochemical parameters of one of these factors, M2, were analyzed. It was found that this monokine had many properties in common with IL1: stimulation of proliferation of thymocytes from C3H/HeJ mice, similar amino acid composition and mobility during isoelectric focusing.

Amino Acids↗

Sympathetic activation on effort in patients with chronic heart failure. Long term effects of captopril.

Ten patients with congestive heart failure (CHF) (NYHA II-IV) on adjusted doses of digitalis and diuretics underwent a careful clinical assessment including an evaluation of exertion dyspnoea and the usual echocardiographic indices of cardiac performance. A cardiopulmonary exercise test with an increment of 20W every 3 minutes was prolonged until exhaustion. Systemic arterial pressure, ECG, VO2, VCO2 and VE were monitored throughout. Gas tensions, plasma catecholamines and lactate were measured in blood samples taken at the first and third minute of each exercise stage. The above measurements were carried out before and after 3 months of treatment with Captopril, 50 mg b.i.d. or t.i.d. A highly significant correlation between arterial lactate and plasma norepinephrine (NE) was observed in each patient during both exercise tests (r = 0.77 to 0.99; p less than 0.05 at least). Left ventricular end-diastolic dimensions were reduced by Captopril (from 69.9 +/- 1.7 to 65.2 +/- 1.4 mm, p less than 0.01) along with a concomitant increase in percent fractional shortening. Most of the patients were reclassified at a lower NYHA class and a significant decrease in dyspnoea score was observed. The exercise time was significantly increased (from 11.2 +/- 1.8 to 12.9 +/- 1.9 min; p less than 0.05), but the peak values of NE, arterial lactate and VO2 were not affected by the treatment. The predicted value of VE at a VCO2 of 1 L/min, regarded as an index of dyspnoea, was significantly decreased by Captopril (from 41.4 +/- 2.9 to 38.9 +/- 2.7 L/min; p less than 0.05). The positive effects of long-term treatment with Captopril on cardiac performance in CHF are confirmed. Sympathetic activity is linked to anaerobic muscular metabolism during exercise and seems to be independent of pharmacological ACE inhibition. The discrepancy between the exercise tolerance and the peak VO2 might be explained by a better utilization of the available energy.

Adult↗

[Purification of human plasma fibronectin by double affinity chromatography on gelatin and heparin-Trisacryl].

In this work the human plasma fibronectin was purified by affinity chromatography using a tandem column system. The first affinity column was filled with gelatin-Trisacryl whereas the second one contained heparin-Trisacryl. This double affinity chromatography demonstrated its high efficiency in term of purity and yield. Several analytical methods (electrophoresis, immunoelectrophoresis, F.P.L.C. and adhesion assay on cultured eucaryotic cells) evidenced in fact the high purity of the preparation as well as its biological behaviour in term of cell adhesion and spreading. The performances of the sorbents used facilitate the scaling up when large quantities of FNP are needed.

Acrylic Resins↗

Acute effects of captopril in hypoxic pulmonary hypertension. Comparison with transient oxygen administration.

The present study was carried out to test the hypothesis of a possible effectiveness of captopril--an enzymatic inhibitor of both angiotensin II formation and bradykinin degradation--on hypoxic pulmonary hypertension. In 6 patients with this clinical condition, captopril-induced changes in pulmonary hemodynamics were observed after the acute administration of the drug with and without a short period of oxygen therapy at a flow rate sufficient to keep the PaO2 over 60 mm Hg. In our patients, captopril significantly lowered pulmonary arterial pressure and vascular resistance only when combined with oxygen, suggesting that an increase in bradykinin availability and/or a decrease in angiotensin II synthesis might be important factors in reversing pulmonary arterial hypertension only after blunting of the hypoxic stimulus on pulmonary circulation. Moreover, the authors suggest that the employment of vasodilators in the setting of hypoxic pulmonary hypertension should be considered not only as a means of relieving vasoconstriction but also as a possible tool for maintaining cardiac output and, in turn, peripheral oxygen delivery.

Aged↗

Acute left ventricular filling time and rate changes in hypertrophic cardiomyopathy after verapamil and propranolol evaluated by nuclear stethoscope.

We have undertaken the present study to evaluate the acute effects of propranolol and verapamil on the diastolic function in patients with hypertrophic cardiomyopathy. We used a non imaging isotope device, the nuclear stethoscope, that has been so far mainly employed for assessment of systolic function, although fitted for detecting diastolic filling rates and times as well. Relative cardiac output, ejection fraction, rapid and slow filling times and rates were measured in five patients suffering from hypertrophic cardiomyopathy in basal conditions and 10.20 and 30 minutes after i.v. administration for either propranolol or verapamil, with a time interval of at least 24 hours between the two acute drug studies. With respect to the baseline values only verapamil showed a significant improvement in rapid and maximum filling rates, suggesting that diastolic function is more beneficially affected by Ca-entry blockers rather than beta-blockers in hypertrophic cardiomyopathy.

Adult↗

Culture of chondrocytes in medium supplemented with fetal calf serum or a serum substitute: Ultroser G.

Fetal calf serum and a serum substitute, Ultroser G, were compared for their effects on the growth curves, clonal growth and cell cycle progression of rabbit chondrocytes in primary culture and during at least three cell passages and included a screen for the maintenance of cartilage-like differentiation i.e. the presence of type II collagen. Proliferation was also compared with another serum substitute, Nu-Serum. Ultroser G is shown to be equivalent to fetal calf serum as far as chondrocyte proliferation is concerned, clonal growth is improved and biosynthesis of type II collagen is maintained in primary culture.

Animals↗

Cell affinity chromatography with ligands immobilized through cleavable mercury-sulfur bonds.

A new methodology for cell separation by affinity chromatography is described. We have conjugated the organomercurial mersalyl to trisacryl beads bearing primary amino groups. Thiolated ligands can be immobilized on this matrix through cleavable Hg-S bonds. Two model studies of cell separation are reported: (i) concanavalin A thiolated with N-succinimidyl-3-(2-pyridyldithio)-propionate and immobilized on mersalyl-trisacryl; mouse thymocytes bound to Con A-mersalyl-trisacryl were eluted from the support by short thiol treatment which preserved cell viability; (ii) anti-dinitrophenyl antibodies modified with S-acetyl-mercaptosuccinic anhydride and immobilized on mersalyl-trisacryl; sheep erythrocytes, previously labelled with trinitrobenzene sulfonic acid, bound to this support and were easily recovered by thiol treatment without hemolysis. This methodology should overcome difficulties frequently encountered in cell affinity chromatography. Cell support multivalent interactions or high affinity of cell-ligand bindings often require drastic elution conditions which prevent viable cell recovery.

Animals↗