PubMed Health⌕ Search

Biomedical subjects

A Denti

Publications and source records attributed to A Denti.

15 recordsLinked to original sources
PubMed1999

Effect of polydeoxyribonucleotides on human fibroblasts in primary culture.

The effects of a mixture of oligo- and polydeoxyribonucleotides (PDRN) on the growth and protein secretion of cultured human skin fibroblasts were investigated. Both intact and DNAase-digested PDRN stimulated cell proliferation to a similar extent. When cultured fibroblasts were incubated with radioactive amino acids in the presence of intact or digested PDRN the incorporation of the tracer into secreted proteins increased significantly. This stimulation appears to be specific for certain protein components, including fibronectin. These results are interpreted assuming that PDRN and the nucleotides and nucleosides resulting from its degradation, can act as signal transducers or, alternatively, can be internalized and utilized to provide purine and pyrimidine rings for the salvage pathways.

Cell Division↗
PubMed1997

Role of decorin on in vitro fibrillogenesis of type I collagen.

Tendon and corneal decorins are differently iduronated dermatan sulphate/proteoglycan (DS/PG) and the biochemical parameter that differentiates type I collagens is the hydroxylysine glycoside content. We have examined the effect of tendon and corneal decorins on the individual phases (tlag, dA/dt) of differently glycosylated type I collagens fibril formation, at molar ratios PG:collagen monomer ranging from 0.15:1 to 0.45:1. The results obtained indicate that decorins exert a different effect on the individual phases of fibril formation, correlated to the degree of glycosylation of collagen: at the same PG:collagen ratio the fibril formation of highly glycosylated corneal collagen is more efficiently inhibited than that of the poorly glycosylated one (tendon). Moreover tendon and corneal decorins exert a higher control on the fibrillogenesis of homologous collagen with respect to the heterologous one. These data suggest a possible tissue-specificity of the interaction decorin/type I collagen correlated to the structure of the PG and collagen present in extracellular matrices.

Animals↗
PubMed1995

Structural heterogeneity of dermatan sulfate chains: correlation with heparin cofactor II activating properties.

To obtain dermatan sulfate (DS) with different structural characteristics and biological properties we isolated three groups of chains from a bovine mucosal DS preparation, differently iduronated and sulfated. The selected DS chains were characterized by their total charge values, electrophoretic mobility, susceptibility to Chondroitinase AC II treatment and disaccharide composition of Chondroitinase ABC digests. Besides the major IdoUA-->GalNac-4-SO4 sequences, two DS fractions (s-DS 1.75 M and f-DS 1.75 M) contained more than 10% disulfated disaccharides sequences and the third DS fraction (s-DS 1.5 M) contained only 4% disulfated disaccharides. Chondroitinase AC II treatment indicated that both the electrophoretically retarded forms (s-DS) are iduronic acid rich, as they were only minimally degraded to disaccharides/oligosaccharides. The ability of DS crude preparation to activate the heparin cofactor II (HCII) mediated inhibition of thrombin depends on the relative amount of highly active DS chains; this activity is related to the overall charge of DS chains and particularly with the content of IdoUA-2-SO4-->GalNAc-4-SO4 and UA-->GalNAc-4,6-di-SO4 disaccharides.

Animals↗
PubMed1988

Passive avoidance learning in the crab Chasmagnathus granulatus.

Male crabs Chasmagnathus granulatus were trained by means of a method similar to the standard inhibitory avoidance technique widely used in vertebrates. Each crab was placed in the dark compartment (DC) of a double-chamber device, allowed to move towards the light compartment (LC) and latency to enter measured. Experimental crabs received a shock in LC, but controls were not punished. After 1 min, both experimental and control crabs were free to return to DC. On completion of 1, 2, 3 or 24 hr intertrial interval in DC a retention test was administered and latency to enter LC was measured. A single trial was proven enough to establish a LC-shock association that was detected up to 3 hr later, but no retention was proved after 24 hr. Memory was disrupted when crabs were removed from the apparatus during the 3 hr intertrial interval. Similarities and differences between the passive avoidance method used with crabs and that used with vertebrates are discussed.

Animals↗
PubMed1977

One trial passive avoidance learning in neonatally hormone treated rats. Its relation with activity.

The performance in one trial passive avoidance learning and the degree of activity were determined in adulthood, from neonatal hormone treated and intact rats. Activity was measured in the same environmental conditions in which the learning test takes place, i.e., shuttle box unequally illuminated. The treated groups were androgenized females and castrated males. Intact groups were composed by normal males and females. Intact females showed more activity than intact males. Castrated males and androgenized females displayed a degree of activity similar to the normal females. This score was negatively correlated with the total time that each animal remained in the dark compartment of the box. In this respect the normal males showed greater dark preference than the other three groups, which had no differences among them. Similar results to that of dark preference were obtained in performance on one trial passive avoidance learning, that is, androgenization in females did not produce a significant effect in this test and castration in males decreased their performance. A linear correlation between activity and passive avoidance score could be established.

Animals↗
PubMed1975

Activity and learning in neonatally hormone treated rats.

The degree of activity and the performance in active avoidance learning were determined in adulthood, from neonatal hormone treated and intact rats. The treated groups were androgenized females and castrated males and females. Normal males and females composed the intact groups. Activity was measured in two tests situations, i.e., open field and shuttle box. Similar results were obtained in both tests, and a positive correlation coefficient was found between them. Intact females showed more activity than males; castration and testosterone injection in females decreased their activity. On the contrary, castration in males increased it. The effects of the treatments on the performance in the active avoidance task were similar to those described for activity, with the only exception that castration in males did not produce a significant effect in this test. Nevertheless, no correlation was found between activity and avoidance learning scores. The validity of the classification of different types of behavior as sexual or non-sexual is discussed.

Animals↗
PubMed1975

Characteristics of the hypothalamic and hypophyseal cytoplasmic estradiol binding substances. Effects of neontaal castration and testosterone administration.

Some physicochemical characteristics and binding capacities of the cytoplasmic estradiol-receptor complexes of the rat hypophysis and hypothalamus, were determined in intact males and females, neonatal castrated males and neonatal and adult testosterone injected females. By gel filtration and density gradient centrifugation the hormone receptor complexes obtained in vitro, shared the same properties in both tissues. The hydrodynamic radius was estimated to be 60 A, The sedimentation coefficient 8.5 S, the frictional coefficient f/fo was 1.42 corresponding to axial ratio (prolate) of 7.85. The molecular weight was 263 000. The data suggest a highly asymmetric molecule similar to the uterine soluble estradiol-receptor complex. No differences were observed in the hypothalamic binding capacities of diestrous females and adult males. The results expressed as fmol of hormone bound/mg cytoplasmic protein were 2.40 +/- 0.32 and 2.54 +/- 0.26, respectively. For estrous females it was 3.72 +/- 0.44. Neonatal castration or testosterone administration increased significantly the binding activity in adulthood. Adult females treated with testosterone showed the lowest level of the hypothalamic estradiol receptors (1.41 +/- 0.56). No differences were observed in the in vitro titration of the pituitary cytoplasmic estrogen binding sites.

Animals↗