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Biomedical subjects

G La Sala

Publications and source records attributed to G La Sala.

10 recordsLinked to original sources
PubMed2002

Influence of an 8-oxoadenine lesion on the structural and dynamic features of a 30-mer DNA fragment with and without a mismatch.

PURPOSE: To elucidate the influence of the oxidative lesion 7,8-dihydro-8-oxoadenine (8-oxoA) on the structural and dynamic features of a 30-mer DNA fragment, and to understand if differences occur when C is positioned opposite 8-oxoA instead of T. MATERIALS AND METHODS: Two 30-mer DNA oligomers with or without the 8-oxoA and two complementary oligomers with C or T base opposite the lesion site were synthesized and annealed. Duplexes named AT, A*T, AC and A*C were characterized by means of circular dichroism and UV denaturation measurements. gamma-Ray footprinting experiments were performed to give insight into their fine three-dimensional structure. Elastic torsional constants were derived by following the decay of the fluorescence polarization anisotropy (FPA) of the ethidium-DNA complexes measured by multifrequency-phase fluorometry. RESULTS: The introduction of one oxidative lesion in a 30-mer DNA oligomer with and without a mismatch did not cause relevant changes in their overall conformation and slightly modified their elastic properties. Small energetic differences were revealed by thermodynamic analysis in the sample bearing both the oxidative lesion and the mismatch. Minor variations in the cleavage pattern due to the hydroxyl radicals in the A*T sample were observed and present along the entire DNA fragment length. In the A*C sample, by contrast, there was a major modification in the cleavage pattern extending for about 11 bases around the lesion, especially towards the 5'-end. CONCLUSIONS: Differences in the fine structure and in the elastic properties between the A*T and A*C samples were observed, while their overall conformation was unchanged. The results are consistent with the hypothesis that the observed local changes of the double helix structure in A*C are due to the pairing of the oxidized adenine in a syn conformation with the cytosine.

Adenine↗
PubMed2001

Physicochemical, mechanical, and biological properties of commercial membranes for GTR.

Barrier membranes for guided tissue regeneration (GTR) to treat bone defects have to satisfy criteria of biocompatibility, cell-occlusiveness, spacemaking, tissue integration, and clinical manageability. In this study, the morphological and mechanical properties of two commercial biodegradable membranes (Resolut LT and Biofix) as a function of the incubation time have been compared. Moreover, their permeability to both fluids and epithelial cells as well as the bacteria adhesion have been evaluated. The membranes are asymmetric and composed of a dense polymeric layer coupled with nonwoven (Resolut LT) or woven (Biofix) fibers. Both of the membranes, when incubated in complete culture medium, completely lose the structural and mechanical properties within 30 days. Moreover the results of solute permeability show that Resolut LT and Biofix membranes cannot be considered selective membranes to the solute crossing. On the contrary, they act as a barrier to the passage of the gingivial cells and to S. mutans bacteria.

Animals↗
PubMed1999

Inhibin B plasma concentrations in oligozoospermic subjects before and after therapy with follicle stimulating hormone.

The aim of this study was to investigate inhibin B and follicle stimulating hormone (FSH) secretion in a large group of oligozoospermic subjects affected by different degrees of testicular damage, before and after FSH treatment. A total of 135 oligozoospermic subjects (sperm count < 20 x 10(6)/ml) were evaluated for seminal parameters and FSH, luteinizing hormone (LH), testosterone and inhibin B plasma concentrations. Testicular structure was analysed with bilateral fine needle aspiration cytology. Inhibin B showed an inverse correlation with FSH, no correlation with sperm concentration and a significant relationship with intratesticular spermatid number, demonstrating that testicular spermatids play an important role in the control of inhibin B production. Twenty-five subjects with sperm counts < 10 x 10(6)/ml were treated with FSH; 11 of these had basal FSH and inhibin B plasma concentrations in the normal range (group A), while in seven subjects FSH was elevated (> 7 IU/l) with normal inhibin B (group B), and in seven patients FSH was high and inhibin B reduced (< 80 pg/ml) (group C). During treatment, in group A patients inhibin B plasma concentrations increased significantly after 2, 3 and 4 weeks of FSH administration and declined thereafter to pre-treatment concentrations. Groups B and C did not show any modification during the treatment. In the same period, in group A FSH increased significantly after 2, 3 and 4 weeks and subsequently declined. In groups B and C, FSH increased significantly after 2 weeks and remained elevated during the following period. The results of the present study confirm the significant inverse correlation between inhibin B and FSH plasma concentrations in subjects with disturbed spermatogenesis, and demonstrate that inhibin B reflects Sertoli cell function and their interaction with spermatids. FSH and inhibin B concentrations are an expression of the spermatogenic status of seminiferous tubules. FSH treatment seems to modify inhibin B plasma concentrations only in subjects with normal basal FSH and inhibin B, independently from the effects of this therapy on sperm production.

Adult↗
PubMed1997

Fatal exacerbation of systemic lupus erythematosus after induction of ovulation.

It is well known that sex hormones can regulate the course of systemic lupus erythematosus (SLE). We describe a young woman who had a fatal exacerbation of SLE after controlled ovarian hyperstimulation for induction of ovulation. We recommend careful attention to the immunological status of the infertile women before starting any ovulation inducing treatment for assisted reproduction.

Adult↗
PubMed1985

[Free uterine autograft fragments interposed on the opposite uterine horn in the female rat].

Vascularised grafts of the tubes have practically been given up now that such progress has been made by in vitro fertilisation. All the same, the possibility of non-vascularised grafts must still exist. We have carried out an experimental study on the uterus of rats. A piece of the uterus 1 cm long was taken from each cornu. After switching the right to the left and vice versa, the grafts were sewn into new sites, either the right way up or the wrong way up, using a microsurgical suture technique. Three out of 20 animals that were operated on became pregnant after having been serviced by the male, of which one was pregnant in both horns. This success was usually associated with putting the graft in the right way round and with an absence of intra-peritoneal adhesions. Of those uteri that did not become pregnant only one had an almost normal histological appearance. All the other had lesions suggestive of more or less severe progressive inflammatory changes or of scar tissue formation. Much more work will be necessary to improve these results for this type of grafting before they can be used in women, whether they be auto or allografts. The main good result from this technique would derive from its ease of operation and eventually a reduction in immunological problems that arise from allografts.

Animals↗
PubMed1981

The unilateral streak gonad syndrome (Slotnick-Goldfarb syndrome).

Two new cases of unilateral streak gonad syndrome are presented. The review of the literature makes it possible to clearly delineate the anatomical, endocrinological and genetic aspects of this syndrome, characterized by secondary amenorrhea, sterility, a streak gonad in the left adnexa and a hypoplastic ovary in the other, while uterus and tubes are normal. Particular attention is devoted to the etiopathogenesis of the syndrome, as well as to the problem of spontaneous sexual development and ovarian function in the streak gonad syndrome.

Adult↗