PubMed Health⌕ Search

Biomedical subjects

C Di Natale

Publications and source records attributed to C Di Natale.

11 recordsLinked to original sources
PubMed2004

Piezoelectric sensors for dioxins: a biomimetic approach.

The aim of this work was to design a fast, cheap and easy to use analytical system for dioxins. Piezoelectric sensors coupled with the pentapeptides as biomimetic traps (the receptors), selective for the dioxins, were used for the realisation of this analytical system. A methodology to select specific receptors among all possible pentapeptides randomly generated was represented by the use of molecular modelling software. Three peptides called later on A, B and C (A:[N]Asn-Phe-Gln-Gly-Ile[C]; B:[N]Asn-Phe-Gln-Gly-Gln[C]; C:[N]Asn-Phe-Gln-Gly-Phe[C]), were selected and evaluated for their potential usage as artificial receptors in solid-gas analysis by using a quartz crystal microbalance (QCM) sensors array. The peptide sequences were functionalised by two terminal cysteine residues in order to achieve a covalent interaction with the QCM gold surface. A manganese-porphyrin complex and two other pentapeptides, a pentaglutamine (pentapeptide D) and a pentalysine (pentapeptide E), were used as negative control sensors. The QCM sensors (A, B and C) gave a good linearity against different sample concentrations of the 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD) and a mixture of dioxins. In particular, the selectivity against 2,3,7,8-TCDD was nicely correlated to the estimated binding energy of the receptors calculated by computational modelling. The cross-reactivity of the system was quantified using commercial polychlorinated biphenyls (PCBs) mixtures (dioxin-like compounds).

Biomimetics↗
PubMed2004

Biological qualification of blood units: considerations about the effects of sample's handling and storage on stability of nucleic acids.

BACKGROUND: In transfusional setting introduction of nucleic amplification technique (NAT) for HBV-DNA, HCV-RNA and HIV-RNA in biological qualification of blood units suggest some problems. At first the opportunity to operate on mini-pool, at second the need to store the samples at +4 degrees C. The authors therefore have tried to estimate the impact of these conditions on the operativity of NAT testing in the transfusional setting. METHODS: The following parameters has been estimated: distribution of viral-load in untreated subjects, stability of nucleic acids during storage at +4 degrees C, stability of nucleic acids after repeated cycles of freezing and defrosting, robustness of the test to the cross-contamination, definition of the detection-limit (95%). Quantitative tests has been performed by using the following kits: Cobas Amplicor HBV Monitor, Cobas Amplicor HCV Monitor, Cobas Amplicor HIV Monitor; the qualitative tests has been performed by using the following kits: Ampliscreen HBV, Ampliscreen HCV 2,0, Ampliscreen HIV 1,5 all supplied by Roche Molecular System (Brancburg, NJ). RESULTS: Viral load in untreated subjects showed wide variation for HBV, HCV and HIV. HBV has been demonstrated much stable to the conservation +4 degrees C also until 168 h while for HCV and HIV a greater decrease of the viral-load was observed. For all and three virus the conservation to +4 degrees C until 72 h does not seem to involve meaningful fall in the viral-load. A remarkable reduction of the viral-load has been observed after five cycles of freezing and defrosting. All the tests showed a good robustness to cross-contamination. The detection-limit (95%) was 8 U/ml for HBV, 21 U/ml for HCV and 27 copy/ml for HIV. CONCLUSIONS: Samples for NAT testing, can be stored until 72 h to +4 degrees C without appreciable lowering of the viral-load. Repeated cycles of changes of state should be avoided. The tests showed a good robustness to cross-contamination. NAT tests for biological qualification of blood units had a minimal sensibility around 50 (copy/unit/ml). In our experience the detection-limit (95%) was 21 U/ml for HCV, 27 copies/ml for HIV, 8 U/ml for HBV. The availability of NAT test for HBV-DNA, HCV-RNA e HIV-RNA, sensitive and reliable, together with epidemiological data, suggest the opportunity to place side by side, in the biological qualification of the blood units, to add the tests for HBV-DNA and HIV-RNA to the test for HCV-RNA mandatory by low, in Italy in the biological qualification of blood units.

Blood Preservation↗
PubMed2004

Use of IgG Avidity test in case definitions of toxoplasmosis in pregnancy.

A survey network for congenital toxoplasmosis (TOXO-NET) was set up in December 1996 in Piedmont (Italy). Participants were asked to classify the infections in pregnant mothers and newborns by the criteria of the European Network on Congenital Toxoplasmosis published by Lebech in 1996. Because the IgG Avidity test is largely employed as a 2nd level test in toxoplasmosis diagnosis and it could be helpful to date infection, the co-ordinators of TOXO-NET suggested including it in the "case definition" of "probable" infection and "unlikely" infection. 117 cases of toxoplasmosis in pregnancy divided into the risk categories under Lebech's criteria were re-examined using the "new" case definitions. 77 out of 117 (65.8%) Toxoplasma gondii infections during pregnancy could be defined with only one serum sample using the IgG Avidity test. The IgG Avidity test proved a useful method to classify the Toxoplasma gondii infections in pregnancy, especially when we had only one serum sample.

Animals↗
PubMed2004

Monitoring of biological odour filtration in closed environments with olfactometry and an electronic nose.

Air treatment with a compact biological membrane filter, and air quality monitoring with an electronic nose were tested in the laboratory on air from a cage containing six mice. Additional analyses of air to and from the filter were performed using olfactometry and ammonia and hydrogen sulphide gas detection tubes. The biological air filter is a module containing biofilm-coated membrane fibres that separate a closed liquid loop from a gas phase. Odour compounds and oxygen diffuse through the membranes from the gas phase to the biofilm, where they are degraded to carbon dioxide and water. The prototype "ENQBE" electronic nose is based on an array of eight thickness shear mode resonators (TSMR), also known in the literature as quartz microbalance sensors. The chemical sensitivity is given by molecular films of metalloporphyrins and similar compounds. Chemical interaction of compounds in the air with the vibrating sensors induces a frequency change of the vibration that can be measured as a signal. The air from the mouse cage had a strong odour (3490 OUE/m3). The biological membrane filter performed well, achieving over 80% odour and ammonia reduction. The electronic nose signal could be correlated with the inlet and outlet air-quality of the biological filter, making it a promising method for monitoring air quality in closed environments.

Air Pollutants↗
PubMed2000

Biomedical application of an electronic nose.

The analysis of volatiles secreted outside the human body to get information on the health status of the individuals has been proposed several times in the past. This kind of analysis is complex both from the point of view of sample collection and data interpretation when, for instance, gas chromatography is utilized. In the recent years the advent of chemical sensors and chemical sensors systems (the so-called electronic noses) opened the way to the possibility of fast and simple analysis of odors in many fields, and, recently, among them, in medicine. In this paper some examples of these applications are illustrated. The results, although preliminary, encourage in pursuing these researches that can give rise to a better comprehension of the role of smell and odor in humans and, possibly in the near future, in novel diagnostic tools.

Adolescent↗
PubMed1999

Electronic nose analysis of urine samples containing blood.

In this paper the possible application of an electronic nose to the analysis of urine is presented. In contrast with the conventional applications of sensors and biosensors operating in liquid, the approach discussed here makes use of gas sensors performing an analysis of the headspace. The application deals with urine samples from patients affected by kidney diseases; some of the samples contained traces of blood. Results show the possibility of distinguishing the samples containing blood from the others, and a linear correlation between the first three principal components and the blood content was found. Furthermore, the electronic nose matched with a suitable neural network showed good performance in measuring the pH and the specific weight of the samples.

Adolescent↗
PubMed1998

Technologies and tools for mimicking olfaction: status of the Rome "Tor Vergata" electronic nose.

This paper shows recent results obtained in the field of artificial olfaction by an electronic nose based on quartz microbalances. The chemical interactive material responsible of the sensitivity is, in this case, porphyrin, whose performance and optical characterization will be presented and discussed. The design of the electronic nose and the kind of neural network that has been considered for these applications will be illustrated and commented. Future research and perspectives toward electronic nose miniaturization are also discussed as fundamental milestones for reaching closer biomimicking action.

Animals↗
PubMed1995

Self-organising sensory maps in odour classification mimicking.

A system for artificial olfaction is introduced, which is composed of a sensor array for gas sensing and a self-organising artificial neural network. A detailed reformulation of the most effective Self-Organising sensory Map (SOM)-based algorithms for odour classification and other applications is provided. An opto-electronic micromachined implementation of the neural network is introduced, which employs a novel hybrid mechanism for activating neural groups, avoiding fabricated cloning templates hardware.

Algorithms↗
PubMed1992

[Herpetic encephalitis with biphasic course. A case report and review of the literature].

Encephalitis represents an important event in pediatric practice. Between the different causes Herpes Simplex Virus (HSV) seems to be the most significant etiological agent, not only for its frequency but chiefly for conditioning prognosis. The Authors report a new case of HSV encephalitis with biphasic course illustrating the most recent pathologic, diagnostic and therapeutic features in the attempt to individualize those factors, between clinical data, laboratory findings and imaging that allow early diagnosis and consequently precocious specific antiviral therapy.

Child↗
PubMedDate not supplied

[Anti-GOR antibodies in type II mixed cryoglobulinemia associated with hepatitis C virus infection].

The frequent association of chronic hepatitic C virus (HCV) infection and type II mixed cryoglobulinemia is considered to be one of the possible signs of interaction between the virus and the immune system. This could also be the case for the appearance of anti-GOR antibodies in serum, as they react with both viral and host antigens. We studied a group of patients with chronic hepatitis C infection and a group with type II mixed cryoglobulinemia associated with HCV infection to ascertain if anti-GOR or other non-organ specific autoantibodies were present in the serum. We found no significant difference between the two groups in presence, prevalence or titer of anti-GOR or other autoantibodies. Moreover, the expression of anti-GOR does not seem to influence the severity of liver damage. Our data support the hypothesis that anti-GOR antibodies are a simple expression of molecular mimicry between viral and human epitopes.

Adult↗