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A Arce

Publications and source records attributed to A Arce.

76 records · Page 5Linked to original sources
PubMedDate not supplied

Partitioning of 1,4-benzodiazepines into natural membranes.

The partition coefficients of several 1,4-benzodiazepin-2-ones (BZDs) were determined in a synaptosomal membrane-buffer system (Pm/b) by a two-component model analysis of the experimental data and the following values were obtained: flunitrazepam (FNTZ) = 32.2 +/- 1.5; diazepam (DZ) = 79 +/- 9; clonazepam (CNZ) = 30 +/- 4; nitrazepam (NTZ) = 38 +/- 2 and chlorodiazepoxide (CDZX) = 15.7 +/- 0.6. Correlations between these Pm/b and other chemical properties were performed by a principal component analysis. Hydrophobicity of BZDs, measured as the partition coefficients in different solvent systems, could be correlated with the presence of a methyl group at position 1 of the seven-member ring of the BZD molecule. The values of the partition coefficients of benzodiazepine in the synaptosomal membrane-buffer system were one order of magnitude lower than those obtained in an octanol-water or in ethyl acetate-water systems. The complexity of the membrane, unlike the isotropy of a pure solvent phase, provides a wide spectrum of types of interactions which, in turn, can be modulated in a dynamic manner by local or generalized changes in the lipid phase state. In that sense, the present values of Pm/b should be interpreted as an average tendency of BZDs to establish non-specific interactions with the molecules present in the different phases within biological membranes. Conversely, these Pm/b values reflect a consequence of the difference in complexity between natural membranes and the systems currently used as membrane models for drug partitioning.

Animals↗
PubMedDate not supplied

[Septo-optic dysplasia].

INTRODUCTION: Septo optic syndrome, described by De Morsier in 1956, consists in the hypoplasia of one or both optic nerves, mid line brain malformations and hypothalamohypophysial dysfunction, which is inconstant. It is an infrequent, but treatable, cause of hepatic and neurological damage, and it is important to obtain an early diagnosis and to begin hormone replacement therapy. CASE REPORT: We report the clinical case of a female baby who was diagnosed early on as suffering from septo?optic dysplasia, after discovery of the existence of cholestatic jaundice. In our case the three components of the syndrome were present: hypothalamohypophysial dysfunction, bilateral hypoplasia of the optic nerves and brain malformations with dysplasia of the transparent septum. All this gives rise to complex clinical features and the predominance of hypernatraemic dehydration secondary to insipid diabetes, nystagmus and serious psychomotor retardation. Our patient died, as in other cases reported in the literature, from an episode of sudden death. DISCUSSION: Despite the importance of an early diagnosis of this disorder, it is usually late. Most children who present hypopituitarism traits in the neonatal period are not diagnosed at that time, with the subsequent risk of death or brain damage. Some clinical findings, which appear early on and can provide clues which aid us to reach a diagnosis, are the appearance of episodes of hypoglycaemia in the neonatal period, the existence of micropenis and cryptorchidism with hypoplasic testes, jaundice or the appearance of clinical manifestations of insipid diabetes. Later on nystagmus and neurological symptoms may appear. The final diagnosis is performed through the use of neuroimaging techniques (CT or MRI) and hormonal studies.

Fatal Outcome↗
PubMedDate not supplied

[Treatment of hepatorenal syndrome with dopamine and bromocriptine].

Two cirrhotic patients with hepatorenal syndrome were treated with Dopamine hydrochloride and Bromocriptine, a Dopamine agonist. Dopamine hydrochloride was given at a dosis of 0.30 to 0.90 mg/min. and Bromocriptine 15 mg/day. Although a transient raise of urinary output was observed in one patient, both patients died six to ten days later with an urinary output of less than 100 ml/day. Dopamine and Bromocriptine combined are of poor therapeutic value in hepatorenal syndrome.

Adult↗