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Biomedical subjects

G De Luca

Publications and source records attributed to G De Luca.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

Effects of a calcium-antagonist (flunarizine) on the in vitro growth of B16 mouse melanoma cells.

Flunarizine, a drug which binds to calmodulin, was found to inhibit both the growth rate and the survival fraction of a B16 mouse melanoma cell line cultured in vitro. Both of these effects, that are dose and time-dependent, occurred at doses which in vitro cause a 50% inhibition of the calmodulin-activated cyclic nucleotide phosphodiesterase prepared from the tumor. Cyclic AMP was increased in treated B16 melanoma cells, while DNA synthesis was inhibited, though the DNA content/cell was increased. The possible mechanisms of the drug's action are discussed herein.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMedDate not supplied

Hypothesis on the role of hydroxylysyl glycosides in collagen fibre organization.

Hydroxylysine (Hyl) glycosides were determined both on the collagen produced by in-vitro cultures of human skin fibroblasts and pig articular chondrocytes and on the insoluble collagen extracted from bovine cornea and sclera. The disorganized collagen present in the culture medium showed a Hyl di- to mono-glycoside ratio markedly higher than the molecules extracted from the cell layer, where electron microscopy investigations demonstrated the real presence of collagen fibres. Moreover in bovine cornea the insoluble collagen showed a ratio Hyl di- to mono-glycoside significantly higher than in sclera, which, on the contrary, possesses fibres with larger mean diameter. The possible conversion of Hyl diglycoside to monoglycoside was suggested by the demonstration of an alpha (1----2) glucosidase activity on Hyl diglycoside , in an enzyme extract from cultured human skin fibroblasts. A role for the processes of collagen glycosylation and deglycosylation was thus considered.

Animals↗
PubMedDate not supplied

Proteoglycan modifications in cultured osteogenesis imperfecta skin fibroblasts.

The PGs produced in the growth medium by skin fibroblast cultures from two O.I. affected patients were investigated. After density gradient centrifugation, in the most dense fraction two main families of molecules appeared. The patient with the more severe clinical picture showed a lower content of the PGs with the highest molecular weight. The GAG composition of PGs was different in the two patients. The more severely affected one showed an increase of HS and a decrease of ChS content, in agreement with the lower value of galactosamine to glucosamine ratio in urinary GAGs.

Cells, Cultured↗
PubMedDate not supplied

Surgical treatment of vertebro-epidural neoplasms of the cervical tract via the anterior approach.

Fifteen cases of vertebral-epidural neoplasms of the cervical tract, treated surgically by the technique of longitudinal median somatotomy with inlay arthrodesis via the anterior approach are presented. Compression of the spinal anterior artery is eliminated by the wide anterior longitudinal exposition, which also creates a support for a possible second operation, either laminectomy or foraminotomy.

Adolescent↗
PubMedDate not supplied

Observations on some rare cases of vertebro-medullar malformations associated with tumors.

Three cases of complex vertebro-medullary malformations of the diastematomyelic type associated with dysembriogenetic tumors are presented. In the first case, a true diastematomyelia, associated with a teratoma of mixed histological structure, is described. In the second and third cases, diplomyelia associated with an epidermoid and a dermoid cyst respectively are reported.

Adult↗
PubMedDate not supplied

[Phosphatidylcholine in the treatment of degenerative spinocerebellar ataxic syndromes. Long-term study of 6 patients].

Six patients: three affected by different forms of inherited spinocerebellar ataxia and the others by acquired sporadic forms, were treated for six months with pure phosphatidylcholine, given orally (3,6 g daily). The open study has shown a significant improvement of spinocerebellar symptomatology after three and six months, in 5 patients. No improvement of the pyramidal symptoms was observed. These results, according to those obtained with lecitin, physostigmine and others choline precursors, suggest a possible pathogenesis with treatment.

Administration, Oral↗
PubMedDate not supplied

Effect of glutamine and nucleosides on prolactin secretion in the rat.

The effect of glutamine and some nucleosides (cytidine and uridine) on basal and stimulated prolactin release was investigated in vivo and in vitro. Acute injection of glutamine did not modify serum prolactin concentration, both in basal and stimulated conditions; conversely repeated administrations of the aminoacid significantly reduced (p less than 0.05) the prolactin surge which occurs at 04:00 p.m. in male rats as well as that induced by the injection of the dopamine antagonist sulpiride. The hypoprolactinemic effect of glutamine was significantly potentiated by uridine and cytidine, which per se were not effective. No significant change in prolactin release was observed when anterior pituitary glands were incubated in presence of the above mentioned drugs. However, repeated in vivo injections of glutamine, uridine and cytidine were able to potentiate the inhibitory effect of dopamine on prolactin release in vitro. These results suggest that both glutamine and the nucleosides cytidine and uridine may influence the activity of the hypothalamic-hypophyseal-prolactin axis, probably via an interference with endogenous neurotransmitters.

Animals↗
PubMedDate not supplied

Glycosaminoglycan alterations in osteogenesis imperfecta.

Urinary GAGs from patients affected with Osteogenesis Imperfecta (O.I.) type I, type II and type III - according to Sillence et al. (1979) - have been investigated. Galactosamine to glucosamine ratio resulted significantly decreased in O.I. type II and III, whereas smaller differences in the mildest type of the disease were observed. Cellulose polyacetate electrophoresis of urinary GAGs purified from some patients showed the presence of a slowly moving polysaccharide substance, which did not appear in normal subjects. Moreover some pathological fractions, mainly constituted of ChS on the basis of chemical analysis and electrophoretic behaviour, were not digested by testicular hyaluronidase and presented anomalous structures as compared with the corresponding normal ones. These results seem to indicate that in some forms of O.I. the metabolic defect(s) not only affects the synthesis or the catabolism of a particular type of collagen, but also involves the proteoglycan component of the connective tissue.

Adolescent↗