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Biomedical subjects

F De Luca

Publications and source records attributed to F De Luca.

At least 19 recordsLinked to original sources
PubMed2006

Water absorption kinetics in different wettability conditions studied at pore and sample scales in porous media by NMR with portable single-sided and laboratory imaging devices.

NMR relaxation time distributions of water (1)H obtained by a portable single-sided surface device have been compared with MRI internal images obtained with a laboratory imaging apparatus on the same biocalcarenite (Lecce Stone) samples during capillary water uptake. The aim of this work was to check the ability of NMR methods to quantitatively follow the absorption phenomenon under different wettability conditions of the internal pore surfaces. Stone wettability changes were obtained by capillary absorption of a chloroform solution of Paraloid PB72, a hydrophobic acrylic resin frequently used to protect monuments and buildings, through one face of each sample. Both relaxation and imaging data have been found in good quantitative agreement each other and with masses of water determined by weighing the samples. In particular the Washburn model of water capillary rise applied to the imaging data allowed us to quantify the sorptivity in both treated and untreated samples. Combining relaxation and imaging data, a synergetic improvement of our understanding of the water absorption kinetics at both pore and sample scales is obtained. Since relaxation data have been taken over the course of time without interrupting the absorption process, simply by keeping the portable device on the surface opposite to the absorption, the results show that the single-sided NMR technique is a powerful tool for in situ evaluation of water-repellent treatments frequently used for consolidation and/or protection of stone artifacts.

Journal Article↗
PubMed2006

The role of water coordination in binary mixtures. A study of two model amphiphilic molecules in aqueous solutions by molecular dynamics and NMR.

Two binary aqueous mixtures which contain the small amphiphilic molecules TMAO (trimethylamine-N-oxide) and TBA (tert-butyl alcohol) have been investigated by molecular dynamics simulations and NMR chemical shift and self-diffusion measurements. TMAO is an osmolyte, while TBA is a monohydrate alcohol. Both possess bulky hydrophobic groups and polar heads, namely, NO in TMAO and OH in TBA. The hydrophilic/hydrophobic content of these isosteric molecules strongly modulates the structure and dynamics of the hydration shell, which is thought to be responsible for the effects observed on proteins and phospholipids. Simulation results, especially on hydrogen-bond networking, spatial correlations, and self-diffusivity, are consistent with NMR data and agree well with previous numerical studies on similar solutions. The methods employed allow the elucidation of the microscopic features of the solutions. For TBA solutions, the hydration shell is found to have a low density and a large spatial spread, and thus, above the molar fraction of 0.03, reduction of hydrophobic hydration drives self-aggregation of the solute. This effect does not take place in TMAO solutions, where the hydration shell is more compact and stable, maintaining its structure over a wider range of solute concentrations.

Computer Simulation↗
PubMed2006

Congenital adenohypophysis aplasia: clinical features and analysis of the transcriptional factors for embryonic pituitary development.

UNLABELLED: Anterior pituitary agenesis (APA) has very rarely been reported. Therefore, its phenotypical and genotypical features are not well known. The aim of this study was to ascertain whether the clinical picture in 4 subjects with APA and multiple pituitary hormone deficiencies (MPHD) was different compared to the one observed in a selected control group consisting of 7 MPHD individuals with hypoplastic (and not aplastic) adenohypophysis and pituitary stalk interruption syndrome. Another goal was to investigate genetic basis of APA by analyzing for the first time in this condition many of the transcriptional factors which are required for both structural development and cellular differentiation of hypophysis. Age at diagnosis was significantly lower in APA children than in controls (1.5+/-2.3 vs 11.1+/-7.6 yr, p<0.0005). Microphallus and neonatal cholestasis were observed only in APA subjects (chi-squared=4.3, p<0.05) and also neonatal hypoglycemia was more frequent in APA patients than in controls (X2=4.05, p<0.05). Molecular analyses of the genes of the transcriptional factors POU1F1, PROP1, LHX3, LHX4, ISL1 and HESX1 detected no mutations in APA patients. CONCLUSIONS: a) if compared with a selected cohort of MPHD patients with both adenohypophysis hypoplasia and pituitary stalk interruption syndrome, the ones with APA show an earlier and more severe picture of hypopituitarism; b) mutations in several transcription factors that are known to be essential for the development of Rathke's pouch are not necessarily found in humans with APA.

Child, Preschool↗
PubMed2006

Testicular microlithiasis heralding mixed germ cell tumor of the testis in a boy.

The clinical implications of the association between testicular microlithiasis (TM) and germ cell tumor (GCT) of the testis are still debated since the natural history of incidentally discovered TM has not been defined. Therefore, it is questionable whether TM can be considered as a precursor of malignancy. We are reporting the case of a 9-yr-old boy with a mixed GCT who had presented 3 yr earlier with TM and hydrocele. This evolution suggests that testicular GCT may develop some years later in a boy with pre-existing and incidentally discovered TM. Our case history and other reports of the literature might suggest a strong association between both conditions, thus vindicating the view that individuals with TM should have clinical and ultrasound follow-up. Longitudinal evaluation may be particularly indicated in the patients with additional testicular dysgenetic features, apart from TM.

Child↗
PubMed2005

Increased liver enzymes and hormonal therapies in girls and adolescents with Turner syndrome.

Elevated liver enzymes can be seen relatively frequently in patients with Turner syndrome (TS), while the pathogenesis of this remains unclear. Our epidemiological and prospective study aimed to investigate: a) the natural 2-yr course of liver disease in a selected cohort of young patients with TS, who had been preliminarily recruited on the basis of persistently elevated liver enzymes; b) the role of prolonged hormonal therapies in the etiology of liver dysfunction. From an overall population of 214 TS patients younger than 20 yr, only 19 (8.9%) were recruited, according to the following inclusion criteria: increased serum concentrations of one or more liver enzymes, exceeding the uppermost limit of the respective normal ranges, and persistence of these liver alterations for 6 months after the preliminary assessment. On the basis of the results of this prospective study, we can conclude that: a) the prevalence of liver abnormalities in girls and adolescents with TS is much lower and more strictly related to hormonal therapies than in TS adults; b) both autoimmunity and obesity are not frequently involved in the etiology of TS liver dysfunction; c) liver damage is either mild or moderate and its severity is not conditioned by karyotype; d) its course may be self-limiting; e) its natural history may be characterized in some cases by a slight deterioration of intrahepatic cholestasis, with no negative repercussions on liver synthetic function.

Adolescent↗
PubMed2005

Analysis of genetic variability within Thelazia callipaeda (Nematoda: Thelazioidea) from Europe and Asia by sequencing and mutation scanning of the mitochondrial cytochrome c oxidase subunit 1 gene.

This study investigated genetic variability within the 'eyeworm'Thelazia callipaeda (Nematoda: Thelazioidea) from Europe and Asia by polymerase chain reaction (PCR)-coupled sequencing and mutation scanning of the mitochondrial cytochrome c oxidase subunit 1 gene (cox 1). Eight different sequence variants of cox 1 (haplotypes) were determined for the 50 individual adult specimens of T. callipaeda (from dogs, foxes or cats from Italy, Germany and the Netherlands and from dogs from China and Korea). Nucleotide variation (0.3--2%) was detected at 23 of 649 positions in the cox 1. Six of these positions were invariable among all 37 individuals from Europe and among the 13 individuals from Asia (irrespective of host origin) but differed (five G<-->A and one C<-->T changes) between Europe and Asia. PCR-based single-strand conformation polymorphism (SSCP) analysis of the most variable portion (v-cox 1) of the cox 1 was validated (for a subset of samples) as a tool to rapidly screen for genetic (haplotypic) variability. The results for the SSCP analysis and sequencing were concordant, indicating that the mutation scanning approach provides a useful tool for investigating the population genetics and molecular ecology of T. callipaeda.

Animals↗
PubMed2004

Determination of moisture fraction in wood by mobile NMR device.

A mobile NMR probe has been used as a non-destructive and non-invasive tool for water content analysis on wood samples. The porosity index, express as the fraction of the sensitivity volume of the probe occupied by water, is here proposed as an alternative to the moisture content index, namely the amount of water mass with respect to the mass of dried sample. In principle the method can be applied to any kind of porous media that has not detectable proton signal from the rigid matrix as, for instance, in building materials. In wood, where proton signal can be detected also from cellulose and others macromolecular components, some considerations and artifices are here proposed for eliminating this contribution. The method has allowed performing moisture volume fraction analysis on wood samples characterized by different wood species, cutting and moisture contents. The NMR data of moisture detection as volume fraction have successfully been compared with those obtained by the gravimetric method.

Journal Article↗
PubMed2004

A low-resolution non-invasive NMR characterization of ancient paper.

The use of a portable NMR device allows a non-invasive investigation of the paper in order to assess the state of conservation of books and documents of historical or artistic interest. The NMR investigation has been found mainly on relaxation measurements whose results seem compatible with different relaxation rates in crystalline and amorphous cellulose domains. By a simplified physical picture based on spin-diffusion it appears possible to detect the alteration of the crystalline/amorphous cellulose balance and therefore to get information on some deterioration processes of paper. The use of a portable NMR device shows great potentiality because of its safe and simple in situ approach to Cultural Heritage documents. In this work, we present a research carried out on a 17th century manuscript.

Anthropology, Cultural↗
PubMed2004

Nutritional, glycometabolic and genetic factors affecting menarcheal age in cystic fibrosis.

Aims of this study were to investigate menarcheal age (MA) and menarcheal determinants in 25 girls with cystic fibrosis (CF) and to compare their MA with their respective mothers'. Patients' MA (13.3 +/- 1.1 yr) was on average significantly higher (p<0.0005) than that of the respective mothers (12.2 +/- 1.0 yr) and positively related to it (r=0.055, p<0.005). Six girls experienced menarche after 14.2 yr, ie after the uppest limit of their mothers' MA range. The only parameter which significantly differentiated these 6 patients from the remaining 19 cases was body mass percentile (BMP). Moreover, in the entire patient series a negative correlation was found between MA and BMP. None of the other clinical parameters correlated significantly with MA. No differences in terms of MA were detected in the subgroups of patients with a different glucose tolerance (GT) status and the 12 girls with a pathological GT were not older at menarche than those with normal GT. No correlations were found between either glucose or insulin areas during oral GT test and MA. In the subgroups of patients with a different genotype menarche occurred at a similar age, irrespectively of their genotype. On the basis of our findings we conclude that: a) a menarcheal delay of approximately 1 yr exists between CF girls and their mothers; b) menarcheal delay in CF is not related to either genotype or disease severity or glycometabolic status; c) the only two factors which are able to affect MA in CF are maternal MA and nutritional status.

Adolescent↗
PubMed2004

[Primary squamous cell carcinoma of the breast: a case report].

INTRODUCTION: Primary squamous cell carcinoma (SCC) of the breast is an extremely rare entity and it has a low incidence in comparison with all other mammary cancers. MATERIAL AND METHODS: We describe a case of SCC of the breast in a 55 year old woman who presented with a painless mass located in the external quadrant of the left breast. The neoformation, once removed, was tamponate formalin fixed and routinely processed for inclusion in paraffin. Sections were stained with haematoxilin-eosin and immunohistochemical and electron microscopy investigations were performed. RESULTS: Histologically, the neoplasia was characterized by cystic cavities covered by nests and sheaths of poorly differentiated squamous cells with keratinized areas. Mitotic activity was high, as well as cellular proliferative index, evaluated by Mib-1 (ki 67) antibody. At immunohistochemistry, the tumor cells were diffusely positive for high molecular weight cytokeratins and c-erbB-2, negative for vimentin, estrogen and progesterone. CD68 and LCA were positive only in the inflammatory cells. Electron microscopy confirmed the epithelial nature of the neoplastic cells. A diagnosis of SCC of the breast was made, and a radical mastectomy was performed. CONCLUSIONS: We make a brief review of the literature and discuss the main histologic criteria for the differential diagnosis with adenocarcinoma of the breast with squamous metaplasia.

Adenocarcinoma↗
PubMed2003

Self-diffusion coefficient by single-sided NMR.

It is presented a novel method for the measure of the self-diffusion coefficient. The method exploits the fixed gradient of an open magnet, as that used in single-sided NMR, and it does not use prior information on T(2). The approach presented in this paper can be practiced also on the fringe field of superconducting magnets and it is based on the construction of the ratios between echoes taken at different interpulses separation in a Carr-Purcell-Meiboom-Gill pulse sequence. The determination of the self-diffusion coefficient facilitates the estimate of T(2) because the transverse relaxation results almost influenced by the molecular diffusion effect, also at the shorter interpulses time, when it is measured in field strongly inhomogeneous.

Journal Article↗
PubMed2003

Molecular epidemiological survey on the vectors of Thelazia gulosa, Thelazia rhodesi and Thelazia skrjabini (Spirurida: Thelaziidae).

A Polymerase Chain Reaction (PCR)- based assay developed for the specific identification of Thelazia gulosa, Thelazia rhodesi and Thelazia skrjabini (Nematoda, Spirurida), which cause bovine ocular thelaziosis, was evaluated for its usefulness in detecting the intermediate hosts and in estimating the infection prevalence of vectors in field conditions throughout 5 years (from 1997 to 2001). A total of 5190 flies were captured and identified as Musca larvipara, Musca osiris, Musca autumnalis, Musca tempestiva or Musca domestica. Genomic DNA was extracted from pools constituted by heads, thoraces, abdomens and wings of 10 flies of each species, and 2076 samples were subjected to a PCR assay to specifically detect the ribosomal ITS-1 sequence of bovine Thelazia. Amplicons were sequenced and subjected to digestion with CpoI restriction enzyme. M. autumnalis, M. larvipara, M. osiris and M. domestica species were shown to be PCR positive. T. gulosa was specifically detected by PCR in M. autumnalis, M. larvipara, M. osiris and M. domestica, whereas T. rhodesi is in M. autumnalis and M. larvipara. Of 27 positive samples, 23 were positive for T. gulosa and 4 for T. rhodesi, with a mean prevalence of 2.86% in the whole fly population collected. The highest mean prevalence values of infection were detected in M. autumnalis (4.46%) and M. larvipara (3.21%), and the former species was confirmed to be the vector of T. gulosa and T. rhodesi. This study is the first report of M. osiris as a vector of T. gulosa and M. larvipara as a vector of T. gulosa and T. rhodesi under natural conditions. The occurrence of Thelazia in fly populations in the Apulia region of Italy (in the 5 grazing seasons considered) indicates that cattle thelaziosis is enzootic in southern Italy. This molecular assay should be a useful epidemiological tool for assessing the role of different species of flies as intermediate hosts of thelaziae.

Animals↗
PubMed2003

Natural history of glucose tolerance, beta-cell function and peripheral insulin sensitivity in cystic fibrosis patients with fasting euglycemia.

OBJECTIVE: The loss of pancreatic beta-cells is thought to be one of the principal causes of diabetes mellitus (DM) in cystic fibrosis (CF), but the role of peripheral insulin resistance (IR) in the pathogenesis of DM in CF remains unclear. The aim of this study was to evaluate whether eventual changes of glucose tolerance (GT) over time were associated with modifications of insulin secretion or sensitivity. METHODS: Plasma glucose and insulin responses to an oral GT test (OGTT) were investigated and reinvestigated 13 Years later in 14 CF patients with initial and persistent fasting euglycemia and no history of insulin treatment. Insulin sensitivity (IS) at both tests was assessed on the basis of insulin and glucose levels both in the fasting state and during OGTTs. RESULTS: From the 1st to the 2nd OGTT: (a) the prevalence of DM responses significantly increased; (b) the areas beneath the respective glucose and insulin curves significantly increased and decreased respectively; (c) IR and IS indices decreased and increased respectively, even in the patients who developed DM; (d) pulmonary function significantly worsened in the entire series, especially in the patients who developed DM. CONCLUSIONS: (i) the natural history of glyco-metabolic status in CF is characterized by deteriorating GT over time; (ii) insulinopenia plays a prominent role in the pathogenesis of GT worsening; (iii) IR does not play any significant part in the pathogenesis of DM development; (iv) deterioration of lung function tests is more severe in the subjects who develop DM over time.

Adolescent↗
PubMed2003

Liver glycogenosis as early manifestation in type 1 diabetes mellitus.

Clinical symptoms and biochemical findings related to liver dysfunction are not generally reported among the presentation features of Type 1 diabetes mellitus (T1DM) in infancy and childhood. To our knowledge this is the first paper reporting two children with a clinical and biochemical picture of hepatic glycogenosis at the presentation of T1DM. In both cases at beginning of insulin therapy liver function and dimensions were absolutely normal, even though glycometabolic status had been severely altered for many days at T1DM onset. Both hepatomegaly and aminotransferase abnormalities were first found only some days after the institution of treatment with supraphysiological insulin doses. In both patients the improvement of glycometabolic control under insulin therapy was followed within some weeks by a complete physical and biochemical recovery, as typically reported in hepatic glycogenosis. These case reports demonstrate that hepatic glycogenosis can occur at any stage of T1DM and may even be one of its earliest manifestations, together with those classically reported at the onset of T1DM. Since long-standing hyperglycaemia and overinsulinisation are metabolic pre-requisites for hepatic glycogen storage, liver glycogenosis should be expected to be not uncommon during the first phases of T1DM, especially in the cases who are initially treated with supraphysiological insulin doses.

Adolescent↗
PubMed2002

Electrical impedance tomography via filtered-back projection of fan current distribution: a numerical simulation.

An approach to electrical impedance tomography (EIT) data acquisition inspired by NMR-filtered back-projection imaging with fan isochromat distribution is proposed. A current projection is generated by injecting current at a certain point of the sample and simultaneously collecting the current itself at different points on the half space opposite the point of current injection. After that, the injection is shifted to another point and collected as above and so on. A very simple algebra and software support the numerical simulations. This method is expected to be more sensitive than the traditional method based on potential measurements. A preliminary low resolution experiment is presented.

Algorithms↗