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Biomedical subjects

G Laganà

Publications and source records attributed to G Laganà.

12 recordsLinked to original sources
PubMed2006

Enzymatic urea adaptation: lactate and malate dehydrogenase in elasmobranchs.

Lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) electrophoretic tissue patterns of two different orders of Elasmobranchii: Carchariniformes (Galeus melanostomus and Prionace glauca) and Squaliformes (Etmopterus spinax and Scymnorinus licha) were studied. The number of loci expressed for these enzymes was the same of other elasmobranch species. Differences in tissue distribution were noted in LDH from G. melanostomus due to the presence of an additional heterotetramer in the eye tissue. There were also differences in MDH. In fact, all the tissues of E. spinax and G. melanostomus showed two mitochondrial bands. Major differences were noted in the number of isozymes detected in the four compared elasmobranchs. The highest polymorphism was observed in E. spinax and G. melanostomus, two species that live in changeable environmental conditions. The resistance of isozymes after urea treatment was examined; the resulting patterns showed a quite good resistance of the enzymes, higher for LDH than MDH, also at urea concentration much greater than physiological one. These results indicated that the total isozyme resistance can be considered higher in urea accumulators (such as elasmobranchs) than in the non-accumulators (such as teleosts).

Adaptation, Physiological↗
PubMed2004

Role of polyols in thermal inactivation of shark ornithine transcarbamoylase.

The ability of activity modulators of ornithine transcarbamoylase (OCT) from the liver of the thresher shark Alopias vulpinus to stabilize the enzyme against thermal denaturation was investigated in the tri-buffer at pH 7.8, at temperatures ranging from 60 to 70 (o)C, in the presence of polyhydroxylic molecules such as glycerol and sugars. The study indicated that in the presence of 0.5 M sugars and 1.6 M glycerol in the preincubation medium the OCT activity increases. When trehalose is introduced directly in the reaction mixture in a range of concentration of 0.25-0.5 M, the activity is lower than that with maltose, glycerol and buffer alone. Kinetic data for carbamoyl phosphate and ornithine with and without maltose and glycerol are similar, whereas trehalose increases the kinetic values. Arrhenius plots show an increase of activation energy due to trehalose, whereas values obtained with maltose and glycerol are similar to the control.

Animals↗
PubMed2004

Polyamines biosynthesis and oxidation in free-living amoebae.

In this paper we describe the polyamine biosynthesis and oxidation processes, giving an overview about recent results in free-living Amoebae. The protozoa polyamine levels are different in comparison with mammalian cells. Also, the polyamine levels in protozoa cells change if these species are pathological or not for the human beings. All the amoeba strains show high concentrations of 1,3-diaminopropane (DAP), spermidine and acetylspermidine while spermine is absent. In these amoeba a considerable polyamine oxidase activity has been found, which acts on N8-acetylspermidine, but not on free polyamines. This enzyme is responsible, together with polyamine acetylase, of DAP synthesis whose function is not well known.

Amoeba↗
PubMed1993

Partial purification and properties of ornithine carbamoyltransferase from Citrus limonum leaves.

Ornithine carbamoyltransferase (carbamoylphosphate: L-ornithine carbamoyltransferase, EC 2.1.3.3) has been partially purified from C.limonum leaves. The data indicate the presence of only the anabolic enzyme. The activity is strongly influenced by pH, ionic strength and ornithine concentration. Optimal activity for the enzyme dissolved in the tri-buffer: diethanolamine,2-(N-morpholino) ethanesulfonic acid, N-ethylenmorpholine (0.051 M/0.1 M/0.051 M) is at pH 9.0, when ornithine is 10 mM. The enzyme catalyses an ordered-sequential process in which carbamoyl phosphate binds first followed by L-ornithine and then L-citrulline leaves followed by phosphate. Support for this statement comes from product inhibition and evidence of abortive ternary complex formation.

Citrus↗
PubMed1989

[Monitoring of intracranial pressure].

A very small fiberoptic catheter initially developed as an intravascular pressure sensor was incorporated into a system to be used as an intracranial pressure (ICP) monitor. 13 patients with intracranial hypertension have been studied with this probe. The clinical experience confirmed the safety, accuracy and reliability of the device. The monitor has functioned very well, and there have been no complications except for two breakages of optic fiber as a result of nursing manoeuvres. This new device can be placed into the ventricular, subdural and epidural space. Camino System appears to offer advantages over other monitors presently in use.

Adult↗