Search PubMed⌕ Search

Biomedical subjects

L Galzigna

Publications and source records attributed to L Galzigna.

At least 73 records · Page 4Linked to original sources
PubMed1983

4-aminobutyric acid methyl ester hydrochloride, a precursor of 4-aminobutyric acid.

4-Aminobutyric methyl ester hydrochloride (GME) is able to cross the blood-brain barrier after intracardiac administration to the rat. GME has an LD50 of 1300 mg/kg in mice and 950 mg/kg in rats, exhibits an antiaggressive effect and is able to decrease isoniazid-induced convulsions in the rat. GME is hydrolyzed to 4-aminobutyric acid (GABA) by brain homogenates, acts as an inhibitor of GABA binding to crude synaptic plasma membranes, activates the release and inhibits the uptake of GABA by rat synaptosomes and acts as a competitive inhibitor of the so-called GABAse system in vitro.

Animals↗
PubMed1983

Inhibitory effect of imipramine on epinephrine-dependent platelet aggregation: "in vitro" studies on platelets from healthy and depressed people.

Inhibitory effect of imipramine on platelet aggregation in healthy and depressed people was studied. A different sensitivity was observed between healthy and depressed people. Two groups (D I and D II) were identified among depressed patients on the basis of sensitivity to imipramine effect. ID50 was calculated for healthy subjects (59.5 +/- 22 microM) and depressed patients (D I: 20 +/- 7 microM - D II: 117 +/- 49).

Adult↗
PubMed1983

Pharmacokinetics and in vitro effects of a 4-aminobutyric acid derivative with anticonvulsant action.

N-trimethyl-acetyl-4-aminobutyric acid, called PG2, is a new anticonvulsant acting as a 4-aminobutyric acid (GABA) pro-drug. The stimulatory effect of PG2 on synaptosomal 14C-GABA release and its inhibitory effect of synaptosomal 14C-GABA uptake were studied together with its pharmacokinetics after intracardiac and oral administration to rat. PG2 is a weak inhibitor of the GABAse system in vitro with an apparent Ki value of 0.83 mmol/l.

Animals↗
PubMed1982

Age-dependent excretion of 3-hydroxy-3-methylglutaric acid (HMG) and ketone bodies in the urine of full-term and pre-term newborns.

Total ketone bodies and 3-hydroxy-3-methylglutaric acid (HMG) were determined in urines of full-term and pre-term newborns from the first day after birth to an age of 17. Significantly higher levels of the two catabolites were observed in the first two weeks of life of the pre-term newborns. A peak of excretion of both ketone bodies and HMG was found between the 7th and the 10th day after birth in both groups of newborns. After the 3rd month there is no significant difference between full-term and pre-term children as far as the excretion of the two analytes is concerned.

Aging↗
PubMed1982

Urinary excretion of 3-hydroxy-3-methylglutaric acid in the diabetic condition.

Urinary levels of 3-hydroxy-3-methylglutaric acid (HMG) were measured by gas-liquid chromatography (GLC) after an extraction with tetrahydrofuran in normal rats, streptozotocin-diabetic rats and starved rats. The analysis was also carried out in the urine of three diabetic patients after suspending the insulin treatment. Detectable amounts of HMG are excreted in urine by normal humans and rats and such an excretion increases in the diabetic condition. Starved rats present only traces of HMG in the urine.

Acetoacetates↗
PubMed1982

Interaction between RNAs from different sources and egg lecithin liposomes.

The interaction of RNAs of molecular weight ranging between 15,000 and 30,000 with egg lecithin large and small unilamellar liposomes has been investigated. Torula and tRNA proved to be incorporated to a similar extent but no linear relationship between molecular weight and percent of incorporation was demonstrated. A relationship between percent of secondary structure of RNA and its ability to be trapped in SUV liposomes is suggested.

Animals↗
PubMed1982

Pharmacokinetics of fructose-1, 6-diphosphate in the rat.

The pharmacokinetics of fructose-1, 6-diphosphate administered to the rat by intravenous injection was studied. Labelled fructose-1, 6-diphosphate was measured in blood, where it reaches the highest amount 10 min after administration, and in different organs. Residual radioactivity was measured in organs 20 min after administration, the highest values being found in the kidney and the lowest in the brain. The hydrolytic activity of the various organs toward fructose-1, 6-diphosphate was measured in organ extracts and was found to be maximal in the kidney and minimal in the brain.

Animals↗
PubMed1982

A new phthalidyl derivative of apovincaminic acid: (3 alpha,16 alpha)-eburnamenine-14 carboxylic acid phthalidyl ester (AF 698). A preliminary report on its chemical and pharmacological properties.

A new phthalidyl derivative of apovincamine, (3 alpha,16 alpha)-eburnamenine-14 carboxylic acid phthalidyl ester (AF 698), has been synthesized as hydrochloride. Its chemical and physical properties are described and its acute toxicity and vasodilator effect assayed in comparison with vincamine hydrochloride. AF 698 proved to possess lower acute toxicity than vincamine. Its peripheral vasodilator action, assayed on the perfused rat lower limb, was higher than that of vincamine. AF 698 was also more effective than vincamine in its central vasodilator activity electrocorticographically evaluated on the response of rabbits to selective cerebral ischaemia. The protective effect against the lethal action of hypobaric hypoxia in mice did not greatly differ between the two drugs.

Animals↗
PubMed1981

Submitochondrial localization and partial purification of the succinylCoA: 3-hydroxy-3-methylglutarate coenzyme A transferase from rat liver.

The presence and the localization of the enzyme catalyzing the transfer of a coenzyme A molecule from succinyl-CoA to 3-hydroxy-3-methylglutarate has been established in rat liver mitochondria. The enzyme was found mainly in the mitochondrial matrix but some activity was also found in the inner membrane fraction. The enzyme has been purified about 100-fold from sonically-disrupted mitochondria by high-speed centrifugation, DEAE-cellulose chromatography, (NH4)2SO4 precipitation and Sephadex G-100 filtration. The enzymatic activity was recovered in the final step as a single peak. The coenzyme A transferase appears to have a molecular weight of 42 000, the highest activity at pH 8.5 and an energy of activation of 13 kcal/mol. Mercaptoethanol increases the activity and improves its stability. The enzyme is different from the succinylCoA: 3-oxoacids coenzyme A transferase and is active also on malonylCoA. The apparent Km values obtained for succinylCoA, malnylCoA and 3-hydroxy-3-methylglutarate were 2.2 . 10(-4) M, 3.7 . 10(-4) M and 1.7 . 10(-3) M, respectively. Acetoacetate, which is the final product of the mitochondrial metabolism of hydroxy-methylglutarylCoA, showed an inhibitory effect on the enzyme activity with a Ki of 0.5 mM. The physiological role of the enzyme is discussed.

Acetoacetates↗
PubMed1981

Change of catalytic properties of erythrocyte acetylcholinesterase after binding to lecithin liposomes.

Phosphatidylcholine and phosphatidylserine + phosphatidylcholine liposomes were prepared with cholate and erythrocyte acetylcholinesterase (EC 3.1.1.7). Dipalmitoyllecithin- and egg lecithin-acetylcholinesterase complexes exhibit an affinity for acetylthiocholine different from that of the free enzyme. The binding to lecithin apparently abolishes the excess substrate inhibition of acetylcholinesterase; the affinity constants of acetylthiocholine, acetylcholine and acetylcarnitine for the lecithin-bound enzymes are higher than the ones found for the free enzyme. Binding to lecithin decrease the optimum pH value for acetylcholinesterase, increase the resistance of the enzyme to heat denaturation and reduces the extent of activation by Ca2+.

Acetylcarnitine↗
PubMed1980

Insulin-lecithin interaction in non-aqueous solvents and its change after application of a static electric field.

The interaction between dipalmitoyl lecithin and egg lecithin with insulin was studied in a non-aqueous solvent such as dioxane-chloroform (1:1) by dielectric constant measurements and absorption spectra. The electrostatic character of the interaction results from the dielectric measurements and the effect of an external application of a static electric field (F = 30 kV/cm) is apparently related to the strength of such an interaction. The different strength of interaction of insulin with the two types of lecithins results also from experiments with a two-phase system.

Animals↗
PubMed1980

Hypothesis on illnesses depending on state transition in cooperative systems: relevance to cancer and schizophrenia.

1. There are some remarkable analogies between neoplastic growth of tissue cells and other pathological events such as functional alterations of the central nervous system resulting in schizophrenic behaviour. 2. Body tissues in general and the central nervous system in particular are highly cooperative systems which can undergo state transitions at critical points. 3. Circadian rhythms may be regarded as giant fluctuations near a critical point. 4. Temperature shifts and changes of other environmental conditions can induce reversible state transitions whose occurrence is indeterminate but whose progress, once they have occurred, is inevitable. 5. Hypothermia may be a useful form of treatment of illnesses such as cancer, that can be reversed, since it is a mean of bringing a system back to its equilibrium. 6. If we assume that characters such as vitamin dependency are gentically transmitted we may envisage that homozygotes for that character have a phenotypic expression which may lead to high probabilities of developing schizophrenia and cancer at two different ages as a result of environment-dependent phase transitions.

Central Nervous System↗