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Biomedical subjects

L Nobile

Publications and source records attributed to L Nobile.

At least 19 recordsLinked to original sources
PubMed1999

A unique carboxy-terminus truncation mutant of the retinoic acid receptor alpha gene associated with a variant marker chromosome in a retinoic acid resistant HL-60 subline.

In order to contribute to the study of the molecular basis of leukemic cellular resistance to the induction of differentiation by all-trans retinoic acid (RA) we have generated and analyzed a mutant, RA-resistant HL-60 cell line. Molecular analysis of the retinoic acid receptor alpha (RARalpha) cDNA disclosed, in one of the two alleles, a novel mutation consisting of a 7-base deletion in the ligand binding domain that includes part of a FokI restriction endonuclease site previously described. As a consequence of this deletion and translational frame-shift, a stop signal is created that truncates the protein at codon 421, disrupting an essential functional component of the receptor. Transducing an epitope tagged RARalpha into the mutant is sufficient to inhibit clonal growth in the presence of RA. Standard cytogenetic analysis, fluorescent in situ hybridization (FISH) and comparative genomic hybridization (CGH) analysis revealed the presence of two RARalpha loci, and showed a composite karyotype with additional abnormalities with respect to the parental line, including a chromosome 8 insertion in a chromosome previously known as marker three.

Alleles↗
PubMed1997

Experimental analysis of tensile properties of some suturing materials.

The aim of the investigation is to quantitatively evaluate the failure load of several suture materials currently used in dentistry surgery. No chromic catgut, silk, Prolene, Ethilon, Ethibond, Vicryl and Vicryl Rapid, obtained from Ethicon s.p.a., in the sizes 3-0, 4-0, and 5-0 have been tested. The analysis has been carried out measuring the diameter of each suture with an optical microscope to determine the accuracy of manufacturers' data. Tensile testing has been performed to evaluate the failure load of each material. Finally, sutures of the same effective diameter class have been compared relative to failure load. Results show that monofilament sutures present a failure load remarkably superior to that of multifilament sutures. Using SEM analysis monofilament sutures present less surface irregularities than multifilament sutures. Only monofilaments Ethilon 4-0 and 5-0, Prolene 4-0, and multifilament no chromic catgut 4-0 and 5-0 meet the requirements of the Italian Pharmacopeia. In contrast, Prolene 5-0 and the other multifilaments, silk, Ethibond, Vicryl and Vicryl rapid, have a larger diameter than that declared on the label by the producer.

Journal Article↗
PubMed1995

[The choleretic effects of licorice: identification and determination of the pharmacologically active components of Glycyrrhiza glabra].

Recent studies indicate that licorice extract, when administered per os or i.v., causes an evident choleretic effect in rats. Aim of this research is to identify and quantify those licorice constituents which are responsable for the observed choleresis. The quali-quantitative analysis of umbelliferon (7-idroxycoumarin), was at first performed by a fluorimetric method, subsequently by a more selective HPLC method. Moreover, this HPLC method allows the determination of glycyrrhizin, an important licorice constituent. Unlike the glycyrrhizin, which is present in a fairly large amount, umbelliferon resulted to be present at a very low concentration (at trace level), both in licorice and in bile. Research is in progress, aiming to determine the substances, beyond glycyrrhizin, which are responsable for the choleretic effect of licorice.

Animals↗
PubMed1994

HPLC determination of glycyrrhizin and glycyrrhetic acid in biological fluids, after licorice extract administration to humans and rats.

Simple and sensitive HPLC methods were developed for the determination of glycyrrhyzin (G) and its main metabolite glycyrrhetic acid (GA) in biological samples, in order to investigate the pharmacokinetic behaviour of G after oral administration of licorice extract (LE) or G to humans and rats. The analysis have been carried out by HPLC with UV detector (251 nm), after a careful pretreatment of the samples. These methods are suitable in terms of precision and accuracy for the G and GA determination in plasma and urine of human volunteers and in bile, plasma ad urine of rats.

Animals↗
PubMed1994

Homeostasis and narcolepsy.

Narcolepsy is characterized by irresistible daytime sleep episodes and cataplectic attacks. Because of the finding of an ultradian rhythmicity of slow-wave sleep in narcolepsy, an alteration of nonrapid eye movement sleep homeostatic regulation has been hypothesized to explain the impairment of the sleep-wakefulness cycle. This hypothesis was tested by two different methods: 1) a sleep-deprivation method (16 or 24 hours) increasing the prior sleep wakefulness and 2) a bed-rest method shortening the prior sleep wakefulness. In both studies normal subjects, sex- and age-matched to narcoleptic subjects, served as controls. Although some differences could be evidenced between the two groups, it was clearly shown that the homeostatic process was functional in narcolepsy and that narcoleptics seemed to be more sensitive to homeostatic regulation of sleep than normal subjects.

Adolescent↗
PubMed1991

Spectrophotometric determination of glutathione and of its oxidation product in pharmaceutical dosage forms.

A simple and sensitive spectrophotometric method suitable for the stability control of pharmaceutical dosage forms containing glutathione (gamma-glutamyl-cysteinyl-glycine), GSH, is described. Besides GSH, the method quantitatively determines its oxidation product, GSSG. The colour reactions of GSH and GSSG with ammonium tetrachloropalladate have been investigated and the optimum reaction conditions, spectral characteristics and composition of the yellow water-soluble complexes have been established. The assay results of pharmaceutical formulations showed good accuracy and precision over the concentration range of 5 x 10(-5)-6 x 10(-4) M GSH.

Amino Acid Sequence↗
PubMed1989

Determination of potassium in pharmaceutical formulations by means of 18-crown-6: extraction studies.

A colorimetric method has been developed for the determination of potassium in pharmaceutical formulations. The method is based on the formation of a complex of potassium with 18-crown-6, followed by conversion to an ion-pair with picrate anion; the ion-pair is extracted with either methylene chloride or toluene-methylene chloride (80:20, v/v) and determined colorimetrically.

Colorimetry↗
PubMed1989

[Gas chromatographic determination of aluminum in pharmaceutical formulations].

A gas chromatographic method for the determination of Al3+ in pharmaceutical formulations, based on the complex formation between the cation and the trifluoroacetylacetone reagent is reported. The results obtained indicate that the proposed method is suitable, on account of accuracy and precision, for a reliable quality control of commercial dosage forms.

Aluminum↗