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Biomedical subjects

P Mariani

Publications and source records attributed to P Mariani.

At least 19 recordsLinked to original sources
PubMed2006

[Prognostic factors for malignant uveal melanoma. Retrospective study on 2,241 patients and recent contribution of monosomy-3 research].

INTRODUCTION: We conducted a retrospective study on the clinical factors influencing the local and general prognosis of patients treated for uveal melanoma with a preliminary analysis of the prognostic value of monosomy 3. PATIENTS: and method: The patients sent to Curie Institute for uveal melanoma have a complete initial clinical evaluation, conservative management by radiotherapy or enucleation, and local and general long-term follow-up. Over the last 5 years, the status of chromosome 3 has been assessed by FISH in the tumors of enucleated patients. Findings concerning the initial workup, treatment, and follow-up are recorded prospectively. We conducted a retrospective study with multivariate analysis of the clinical factors influencing local recurrence, ocular conservation metastasis, and survival and studied the effect of monosomy 3. RESULTS: A total of 2241 patients were registered with a median follow-up of 72 months. Of these patients, 92.8% had conservative management with iodine 125 brachytherapy or proton beam therapy and 7.2% of the patients had enucleation (n=160). Tumors from 120 patients were studied for the status of chromosome 3 by FISH. The overall survival rate was 76.3% and the metastatic rate was 19.5%. The clinical factors influencing survival were the size and location of the tumor, age of the patient, gender, and initial treatment. The factors influencing the metastatic risk were the same plus retinal detachment and local recurrence. Monosomy 3 was a significant risk factor for metastatic disease. DISCUSSION: This study found the usual risk factors with the difference that location on the equator seems to be of worse prognosis than ciliary body involvement for survival and metastasis. In addition, the initial retinal detachment appears to be a risk factor for local recurrence and metastasis. At present, the evaluation of chromosome 3 is available for enucleated tumors but it could probably be done on needle biopsy performed during conservative management as well. CONCLUSION: This study confirms previous results on the prognostic factors of uveal melanoma and on the value of monosomy 3. The increasingly precise identification of a group of high-risk patients should allow us to propose adjuvant therapy and to adapt follow-up.

Disease-Free Survival↗
PubMed2006

Single nucleotide polymorphism discovery in the avian Tapasin gene.

Tapasin is a transmembrane glycoprotein located in the endoplasmic reticulum. Its function is to assist the assembly of major histocompatibility complex class I molecules. The chicken Tapasin gene includes 8 exons and is localized inside the major histocompatibility complex between the 2 class IIbeta genes. The aim of the current study was the estimation of single nucleotide polymorphism frequency within the avian Tapasin gene. The Tapasin gene sequence from exon 5 to exon 6 was amplified for the chicken, turkey, and pheasant, and sequences of different lengths were obtained. The sequence analysis based on PolyBayes identified 25 putative single nucleotide polymorphism sites when the 3 species were compared. The coding sequences were further translated and analyzed to identify amino acid substitutions. The results indicated that polymorphisms within this region of the gene was mainly observed in the heterozygous state. The level of conservation of the Tapasin gene sequence among species is likely to be related to the functional importance of the gene.

Amino Acid Sequence↗
PubMed2005

On the importance of anandamide structural features for its interactions with DPPC bilayers: effects on PLA2 activity.

The acylethanolamide anandamide (AEA) occurs in a variety of mammalian tissues and, as a result of its action on cannabinoid receptors, exhibits several cannabimimetic activities. Moreover, some of its effects are mediated through interaction with an ion channel-type vanilloid receptor. However, the chemical features of AEA suggest that some of its biological effects could be related to physical interactions with the lipidic part of the membrane. The present work studies the effect of AEA-induced structural modifications of the dipalmitoylphosphatidylcholine (DPPC) bilayer on phospholipase A2 (PLA2) activity, which is strictly dependent on lipid bilayer features. This study, performed by 2-dimethylamino-(6-lauroyl)-naphthalene fluorescence, demonstrates that the effect of AEA on PLA2 activity is concentration-dependent. In fact, at low AEA/DPPC molar ratios (from R = 0.001 to R = 0.04), there is an increase of the enzymatic activity, which is completely inhibited for R = 0.1. X-ray diffraction data indicate that the AEA affects DPPC membrane structural properties in a concentration-dependent manner. Because the biphasic effect of increasing AEA concentrations on PLA2 activity is related to the induced modifications of membrane bilayer structural properties, we suggest that AEA-phospholipid interactions may be important to produce, at least in part, some of the similarly biphasic responses of some physiological activities to increasing concentrations of AEA.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed2005

Tumor necrosis factor alpha (TNFalpha) and its soluble receptor p75 (sTNF-R p75) in familial combined hyperlipidemia (FCHL).

BACKGROUND AND AIM: Familial combined hyperlipidemia (FCHL) is a genetic disorder of lipid metabolism associated with insulin resistance and abnormalities in fatty acid metabolism whose underlying mechanisms are largely unknown. Perturbations in the TNFalpha/TNF-R pathway may play a role in these abnormalities. METHODS AND RESULTS: We determined plasma levels of TNFalpha and sTNF-R p75 in 85 FCHL patients (TC 245+/-45 mg/dl; TG 260+/-148 mg/dl; apoB 148+/-37 mg/dl) and in 29 age- and sex-matched normolipemic relatives (NL) (TC 187+/-22.8 mg/dl; TG 115+/-37 mg/dl; apoB 106+/-16 mg/dl). Thirty-four normolipemic subjects (TC 180+/-34 mg/dl; TG 107+/-42 mg/dl; apoB 95+/-22 mg/dl) were also included as unrelated controls (NC). Plasma free fatty acids (NEFA) were also measured and insulin sensitivity was evaluated by HOMA. Levels of sTNF-R p75 were significantly reduced in FCHL compared to NL (2.30+/-0.55 ng/ml vs. 2.64+/-0.88 ng/ml, p<0.05) but not compared to NC (2.35+/-0.68 ng/ml). HOMA values were comparable in all groups and did not show any relation with plasma levels of sTNF-R p75. Logistic analysis demonstrated that a low concentration of sTNF-R p75 was an independent predictor of the affected status within FCHL families, but this role was no longer evident when FCHL patients were compared to NC. In FCHL, age (p<0.001) was positively, and TG (p=0.029) and HDL-C (p=0.025) were negatively correlated with plasma concentrations of sTNF-R p75. In the other groups, age (in NL) and non-HDL-C (in NC) were significantly correlated with sTNF-R p75. CONCLUSIONS: Although our data do not support a causative role of TNFalpha/TNF-R alterations in FCHL, they confirm that variation in TNF-R shedding may influence lipid phenotypic expression in FCHL families.

Adult↗
PubMed2004

A pediatric cluster of Shigella dysenteriae serotype 1 diarrhea with hemolytic uremic syndrome in 2 families from France.

We report a cluster of pediatric diarrhea due to Shigella dysenteriae serotype 1 involving 11 children in France, including the index case, who had returned from Senegal. Child-to-child transmission was documented by ribotyping. Five children developed hemolytic uremic syndrome (HUS). On the basis of our findings, the choice of antimicrobial treatment for infections with S. dysenteriae serotype 1 should take into account widespread drug resistance and the risk of HUS.

Anti-Bacterial Agents↗
PubMed2004

Dynamic light scattering and 31P NMR study of the self-assembly of deoxyguanosine 5'-monophosphate: the effect of added salt.

Self-assembling and dynamical properties of deoxyguanosine 5'-monophosphate in isotropic aqueous solutions were studied by (31)P NMR spectroscopy and dynamic light scattering (DLS). All solutions had the same c = 4 wt% guanosine concentration, while the added KCl molarity ranged from 0 to 1.5 M. (31)P NMR measurements show that potassium ions strongly enhance the stacking process of guanosine tetramers until a saturation is reached at 0.1 M KCl with more than 70% of the molecules aggregated. Polarized light scattering reveals the presence of a fast relaxation mode that arises from the translational dynamics of the self-assembled stacks. The diffusion coefficient of this mode shows a strong dependence on molarity of added salt, which can be described in terms of the coupled mode and counterion condensation theories for polyelectrolyte solutions. Depolarized light scattering reveals the rotational dynamics of the self-assembled stacks which exhibits a pronounced slowing down with increasing the added salt content.

Biophysical Phenomena↗
PubMed2003

[Bilateral jugular thrombosis in Lemierre syndrome].

An adolescent presented with a rhinosinusitis complicated with bilateral jugular veins and left superior ophthalmic vein thrombosis and respiratory distress with pulmonary hypertension. Blood culture was positive for Haemophilus influenzae and sinus puncture for Streptococcus constellatus. Evolution was under control after 1 week of appropriate antibiotherapy, antithrombotic and anti-inflammatory treatment. He had no neurologic, respiratory or ophthalmologic sequelae 6 months later. Despite lack of pharyngitis or isolation of anaerobic species on blood cultures, the picture was considered compatible with Lemierre syndrome. The risk for such a complication should be considered in cases of severe otorhinolaryngologic infection in young adults.

Adolescent↗
PubMed2003

Comparison of epidural, continuous femoral block and intraarticular analgesia after anterior cruciate ligament reconstruction.

BACKGROUND: The purpose of this study was to compare three locoregional techniques of pain management after arthroscopic anterior cruciate ligament reconstruction (ACLR). METHODS: Sixty ASA I-II subjects were enrolled after obtaining written informed consent. Patients were randomly allocated to three groups of 20 subjects. The first group (EPI) received epidural ropivacaine 0.2% plus sufentanil 0.2 micro g ml-1, at 5 ml h-1. Patients in the second group (CFB) were given a continuous infusion of the same analgesic mixture through a femoral catheter. The third group (IA) received a continuous intraarticular infusion of ropivacaine 0.2% plus sufentanil 0.2 micro g ml-1, at 5 ml h-1. All subjects were allowed PCA boluses of 5 ml of local anesthetic. Analgesia was assessed for 36 h after the end of surgery by means of a visual analog scale (VAS) and a verbal scale (VS), as well as the number of PCA boluses administered and the amount of supplementary i.v. ketorolac, if given. RESULTS: The VAS and VS scores were significantly higher in group IA during the 24 h following surgery. Ketorolac requirement was higher in group IA throughout the postoperative observation. Adverse effects were similar in all groups except for urinary retention, which was significantly more frequent in group EPI. CONCLUSIONS: We conclude that either epidural or continuous femoral nerve block provide adequate pain relief in patients who undergo ACLR, whereas intraarticular analgesia seems unable to cope satisfactorily with the analgesic requirements of this surgical procedure.

Adult↗
PubMed2002

High-resolution genetic map of bovine chromosome 29 through focused marker development.

Chromosome-specific libraries aid in the development of genetic maps and focus marker development in areas of the genome with identified quantitative trait loci (QTL). A small-insert BTA29 library constructed by microdissection of a 1:29 Rb-fusion cell line, was screened for dinucleotide repeats (CA)(15) and/or (GA)(15) with the goal of generating new genetic markers for this, the smallest bovine autosome. A total of 90 primer pairs were designed and 82 of these successfully amplified bovine genomic DNA by PCR. In addition to these 82 loci, primer pairs were developed for nine putative genes identified from the sequenced clones by BLAST searches of GenBank. A somatic cell panel was used to test for synteny of the new loci with two previously mapped BTA29 markers located on the MARC bovine linkage map. A total of 75 of the 82 microsatellite (ms) loci were integrated into the MARC bovine linkage map. Linkage analysis placed 69 ms markers on BTA29, five on BTAX and one on BTA1. Combined results of the somatic cell and linkage analyses place 79 new markers (ms and gene-related) on BTA29, six loci on BTAX and two loci on BTA1. The results of this effort significantly increase the marker density on BTA29, expanding the ability to fine map QTL associated with this chromosome.

Animals↗
PubMed2001

Localization to chicken chromosome 5 of a novel locus determining salmonellosis resistance.

Clear genetic differences in the susceptibility of chickens to visceral infection by Salmonella have been observed and it has been possible to identify resistant and susceptible lines of inbred chickens. We report here the results of experiments to map directly the gene(s) controlling this trait in chickens by examining crosses between highly susceptible and highly resistant lines. In the mapping panel, a region on chicken Chromosome (Chr) 5 was found to have a large effect on resistance, and this effect was observed in three separate resource populations. Mapping of additional marker loci in the region of the resistance gene further localized it to a region of approximately 2 cM, close to the genes for creatine kinase (CKB) and dynein (DNCH1). This region shows conserved synteny with telomeric regions of human Chr 14 and mouse Chr 12. On the basis of this conserved synteny, this resistance gene seems unlikely to correspond to the previously identified salmonellosis resistance genes Lps (located on mouse Chr 4) or Nos(2) (located on mouse Chr 11). There was no association between Nramp1 and resistance in these crosses, although this gene was shown to contribute to resistance in other crosses. The homologous human and mouse regions at present contain no likely candidate genes for this trait. Thus this appears to be a novel resistance gene, which we designate SAL1.

Animals↗
PubMed2001

Sugar-induced stabilization of the monoolein Pn3m bicontinuous cubic phase during dehydration.

To explore the molecular mechanism of the protective function of sugars on cubic lipidic systems, the mesomorphic properties of the monoolein-water system, dehydrated in the presence of a series of sugars, have been studied by osmotic stress experiments. Two bicontinuous inverse cubic structures (Pn3m and Ia3d) and a lamellar L(alpha) phase form under dehydration in pure water. In sugar solutions, the Pn3m phase shows an extraordinary stability: as a function of sugar concentration, the lattice parameter decreases to very low values, but no phase transitions occur. Instead, the Pn3m to Ia3d phase transition is obtained by equilibrating the lipid phase with aqueous polymer solutions of increasing osmotic pressure. As a result, the pressure at which the phase transition occurs strongly depends on sugar concentration. The free-energy curves obtained from the osmotic-pressure unit-cell data show that the sugar exerts an additional stabilization on both the cubic phases. The analysis of the structural parameters indicates that sugars alter the interface geometry. We suggest that a consequent release of stretching contributions in the chain packing or a reduction of the inhomogeneity in molecular splay mainly stabilize the Pn3m phase and prevent the transition to the Ia3d phase on dehydration.

Biophysics↗
PubMed2001

The self-assembly of a lipophilic guanosine nucleoside into polymeric columnar aggregates: the nucleoside strucutre contains sufficient information to drive the process towards a strikingly regular polymer.

Lipophilic guanosine derivatives act as self-assembled ionophores. In the presence of alkali metal ions in organic solvents, these G derivatives can form tubular polymeric structures. The molecular aggregates formed by 3',5'-didecanoyl-2'-deoxyguanosine (1) have been characterised by SANS and NMR spectroscopy. The polymer is structured as a pile of stacked G quartets held together by the alkali metal ions that occupy the column's central channel. The deoxyribose moieties, with their alkyl substituents, surround the stacked G quartets, and the nucleoside's long-chain alkyl tails are in intimate contact with the organic solvent. In this polymeric structure, there is an amazing regularity in the rotamers around the glycosidic bond within each G quartet and in the repeat sequence of the G quartets along the columns. In hydrocarbon solvents, these columnar aggregates form lyomesophases of the cholesteric and hexagonal types.

Biopolymers↗
PubMed2001

Columnar lyomesophases formed in hydrocarbon solvents by chiral lipophilic guanosine-alkali metal complexes.

The lipophilic guanosine derivative 1 acts as a self-assembled ionophore and, in the presence of alkali metal ions, forms chiral polymeric structures in organic solvents. These polymeric columnar aggregates are comprised of G-quartets held together by alkali metal ions which are located inside the tubular structure; the quartets are surrounded by hydrocarbon chains. In hydrocarbon solvents, these columnar aggregates form lyomesophases of the cholesteric and hexagonal type. Copyright 2000 Wiley-Liss, Inc.

Journal Article↗
PubMed2001

Structural characterization of the pH-denatured states of ferricytochrome-c by synchrotron small angle X-ray scattering.

The ferricytochrome-c (cyt-c) shows a complex unfolding pathway characterized by a series of stable partially folded states. When titrated with HCl at low ionic strength, two transitions are detected. At pH 2, cyt-c assumes the U1 unfolded state, whereas the successive addition of Cl(-) ion from either HCl or NaCl induces the recompaction to a molten globule conformation (A1 and A2 states, respectively). A second unfolded state (U2) is also observed at pH 12. Recent data evidence different features for the local structure of the heme in the different states. To derive relationships between local and overall conformations, we analyzed the structural characteristics of the different states by synchrotron small angle X-ray scattering. The results show that in the acidic-unfolded U1 form the protein assumes a worm-like conformation, whereas in the alkaline-unfolded U2 state, the cyt-c is globular. Moreover, the molten globule states induced by adding HCl or NaCl to U1 appear structurally different: in the A1 state cyt-c is dimeric and less compact, whereas in the A2 form the protein reverts to a globular-like conformation. According to the local heme structure, a molecular model for the different forms is derived.

Animals↗
PubMed2001

An allele associated with a non-detectable amount of alpha s2 casein in goat milk.

The goat CSN1S2 locus is characterized by the presence of three alleles, A, B and C, all associated with about 2.5 g/l of protein per allele. The SDS-PAGE analysis of 441 individual milk samples obtained from goats belonging to a population reared in Southern Italy showed that the milk produced by three goats did not apparently contain alpha s2-casein, whereas milk produced by 37 goats showed a less intense electrophoretic band of this casein fraction (about 50%). These results can be explained by hypothesizing the presence of another allele at this locus, CSN1S2o, associated with a 'null' content of alpha s2-casein. Southern blot, PCR and PCR-RFLP analyses of the DNA region containing the CSN1S2 gene of individuals producing milk with and without alpha s2-casein did not show differences between the two groups. As a consequence, goats producing milk without alpha s2-casein carry an apparently intact gene. The first results obtained by sequencing part of the CSN1S2o allele revealed a G-->A transition at nucleotide 80 of the 11th exon which creates a stop codon and could be responsible for the absence of the alpha s2-casein in goat milk. This mutation eliminates a NcoI restriction site. A test based on this polymorphism has been established in order to identify carriers of the CSN1S2o allele.

Alleles↗