PubMed Health⌕ Search

Biomedical subjects

D Ferrara

Publications and source records attributed to D Ferrara.

At least 19 recordsLinked to original sources
PubMed2003

An unusual and persistent contamination of drinking water by cutting oil.

Drinking water contamination by materials, such as cutting oil, used to set up pipelines is an uncommon but possible event. This paper describes the analytical procedures used to identify the components of that contaminant in drinking water. Volatile and semi-volatile chemical species, responsible for an unpleasant taste and odour, were recognised by solid phase microextraction and GC/MS techniques. Among the volatile compounds, the presence of xylenes, bornyl acetate and diphenyl ether was confirmed by certificate standards and quantified in the most contaminated samples.

Environmental Monitoring↗
PubMed2003

Chemical evidence and risks associated with soybean and rapeseed meal fermentation.

The storage and transport of cereals and foodstuffs present recurrent problems. They may be attacked by insects or, under certain conditions, they may undergo spontaneous fermentation. Insect attack is normally avoided by fumigants, while fermentation, which depends on parameters such as temperature and humidity, is more difficult to stop and can produce chemical compounds which irremediably modify the nutritional and compositional properties of foodstuff. This paper describes the main chemical compounds produced by fermentation and self-ignition of soybean and rapeseed meal. Reported cases occurred in a storage site and during transport by ship, respectively.

Brassica rapa↗
PubMed2003

Pulsatile and steady 24-h blood pressure components as determinants of left ventricular mass in young and middle-aged essential hypertensives.

In order to explore the relations between left ventricular mass (LVM) and the pulsatile (pulse pressure) and steady (mean pressure) components of the blood pressure (BP) curve, 304 young and middle-aged essential hypertensive patients were studied by means of 24-h ambulatory BP monitoring and echocardiography. In the overall study population, both the BP components showed significant correlations with LVM. These correlations were unevenly distributed in the subgroups of subjects younger and in those older than 50 years. While in this latter subgroup, in multivariate analysis, both 24-h mean BP (24-MBP) (beta = 0.27; P = 0.008) and 24-h pulse pressure (24-h PP) (beta = 0.23; P = 0.02) were associated with LVM, in the subset of younger hypertensives only 24-h MBP (beta = 0.21; P = 0.009) was related to LVM, independent of other covariates. The relations observed between 24-h PP and LVM in the entire study population and in the patients older than 50 years lost statistical significance when the effect of 24-h systolic blood pressure (24-h SBP) was taken into account, in a multiple regression model in which 24-h MBP was replaced by 24-h SBP. Our findings seem to suggest that the association of PP with LVM in middle-aged hypertensives may partially explain the increased cardiovascular risk, documented in subjects with high PP. However, this relation is not independent, but is mediated by SBP.

Adult↗
PubMed2001

Relationships between 24 h blood pressure load and target organ damage in patients with mild-to-moderate essential hypertension.

OBJECTIVE: To analyse the relationships between 24 h blood pressure load (the percentage of systolic/diastolic blood pressures exceeding 140/90 mmHg while awake and 120/80 mmHg during sleep) and some indices of hypertensive target organ involvement, independently of the mean level of 24 h blood pressure. METHODS: One hundred and thirty patients with mild-to-moderate hypertension underwent 24 h ambulatory blood pressure monitoring, ocular fundus examination, microalbuminuria assay and two-dimensional guided M-mode echocardiography. The study population was divided into subsets according to the systolic and diastolic 24 h blood pressure load values predicted from the regression equation relating 24 h blood pressure load to 24 h mean blood pressure. The subjects with an observed load above this predicted value were included in the higher blood pressure load groups, the remaining ones being included in the lower groups. RESULTS: Relative myocardial wall thickness and total peripheral resistance were greater, and mid-wall fractional shortening, end-systolic stress-corrected mid-wall fractional shortening and cardiac index lower, in the subjects with a higher systolic blood pressure load. Moreover, the stroke index:pulse pressure ratio was reduced, and a greater prevalence of hypertensive retinopathy was observed in the higher systolic load group. On the contrary, no statistically significant difference was found for any of the cardiac, renal and funduscopic parameters examined when the two groups with a higher and lower 24 h diastolic blood pressure load were compared. CONCLUSIONS: Our results seem to suggest that, in mild-to-moderate arterial hypertension, a high 24 h systolic blood pressure load may be associated, independently of the average level of 24 h systolic ambulatory blood pressure, with an adverse cardiovascular risk profile.

Adult↗
PubMed2000

Acetylcholine biosensor involving entrapment of acetylcholinesterase and poly(ethylene glycol)-modified choline oxidase in a poly(vinyl alcohol) cryogel membrane.

A bienzymatic sensor for the determination of acetylcholine was prepared by physical coimmobilization of acetylcholinesterase and poly(ethylene glycol)-modified choline oxidase in a poly(vinyl alcohol) cryogel membrane obtained by a cyclic freezing-thawing process. The enzyme-modified polymer was applied on a platinum electrode to form an amperometric sensor, based on the electrochemical detection of enzymatically developed hydrogen peroxide. The analytical characteristics of this sensor, including calibration curves for choline and acetylcholine, pH, and temperature effects, and stability are described.

Journal Article↗
PubMed2000

Simultaneous detection and quantification of minimal residual disease in childhood acute lymphoblastic leukaemia using real-time polymerase chain reaction.

A number of prospective studies have indicated the clinical utility of measuring minimal residual disease (MRD) in childhood acute lymphoblastic leukaemia (ALL) and have highlighted the need for improved methodology for quantification of residual disease. We describe a novel real-time polymerase chain reaction (PCR) strategy for MRD analysis based on the exonuclease activity of Taq polymerase to cleave a fluorescently labelled probe. Using a consensus probe designed to the framework 2 region of the IgH gene, together with leukaemia-specific primers, the utility of this technique for simultaneous detection and quantification of MRD was demonstrated in samples from six ALL patients. This technique provides a rapid quantitative assay for determining MRD levels which lends itself to the routine monitoring of minimal residual leukaemia.

Bone Marrow Cells↗
PubMed1999

Amperometric biosensor involving covalent immobilization of choline oxidase and butyrylcholinesterase on a methacrylate-vinylene carbonate co-polymer.

A two-enzyme sensor for the determination of choline esters was prepared by the covalent co-immobilization of choline oxidase and butyrylcholinesterase on polymer membranes, obtained by radiation-induced co-polymerization of 2-hydroxyethylmethacrylate and vinylene carbonate at low temperature. The enzyme-modified membrane was applied to a platinum electrode and the determination of substrates was based on the electrochemical detection of enzymically generated H2O2. The analytical characteristics of this sensor, including the optimization of immobilization procedures, calibration curves for different substrates, pH and temperature effects and stability, are described.

Alcohol Oxidoreductases↗
PubMed1998

Covalently immobilized choline oxidase and cholinesterases on a methacrylate copolymer for disposable membrane biosensors.

Bienzymatic sensors for the determination of esters of choline were prepared by covalent co-immobilization of cholinesterases and choline oxidase on polymer membranes, obtained by radiation-induced copolymerization of 2-hydroxyethyl methacrylate and glycidyl methacrylate at low temperature. Optimization of the covalent attachment of choline oxidase and acetyl- or butyrylcholinesterase to copolymer was explored. The enzyme-modified polymers were applied on platinum electrodes to form amperometric sensors, based on the electrochemical detection of enzymatically developed hydrogen peroxide. Acetyl-, acetylthio-, butyryl-, and butyrylthiocholine contents in standard solutions were measured, and linear calibration curves were determined. Temperature and pH effects on the electrochemical response are described.

Alcohol Oxidoreductases↗
PubMed1998

Treatment strategies for insulin-dependent diabetics with ESRD: a cost-effectiveness decision analysis model.

Clinical decision analysis has become an important tool for evaluating specific clinical scenarios and exploring public health policy issues. A decision analysis model that incorporates patient preferences regarding various outcomes, as well as cost, may be particularly informative in patients with type I diabetes and end-stage renal disease (ESRD). Such a model that includes pancreas transplantation as a treatment choice has not been performed and is presented in this study. The decision tree consisted of a choice between four possible treatment strategies: dialysis, kidney-alone transplant from a cadaver (KA-CAD) or living donor (KA-LD), and simultaneous pancreas-kidney (SPK) transplant. The analysis was based on a 5-year model, and the measures of outcome used in the model were cost and cost adjusted for quality of life. The measure of preference for quality of life was obtained using the "Standard Reference Gamble" method in 17 SPK transplant recipients who underwent transplantation between January, 1992 and June, 1996 at our center. The measures for various outcome states (mean +/- 1 SD) were dialysis-free/insulin-free = 1, dialysis-free/insulin-dependent = 0.6 (0.4 to 0.8), dialysis-dependent/insulin-free = 0.5 (0.36 to 0.64), dialysis-dependent/insulin-dependent = 0.4 (0.21 to 0.59), and death = 0. The expected 5-year costs for each of the treatment strategies in the model were dialysis, $216,068; KA-CAD transplant, $214,678; KA-LD transplant, $210,872; and SPK transplant, $241,207. The expected cost per quality-adjusted year for each of the treatment strategies in the model were dialysis, $317,746; KA-CAD transplant, $156,042; KA-LD transplant, $123,923; and SPK transplant, $102,422. SPK transplantation remained the optimal strategy after varying survival probabilities, costs, and utilities over plausible ranges by means of one-way sensitivity analysis. In conclusion, according to the 5-year cost-utility model presented in this study, SPK transplantation is the most cost-effective treatment strategy for a patient with type I diabetes and ESRD. From a policy standpoint, looking at the cost alone of pancreas transplantation is deceiving. In these patients, who may view various outcome states differently, it would be important to take into account cost adjusted for quality of life when evaluating this procedure.

Adult↗
PubMed1998

Molecular detection of acute lymphoblastic leukaemia in boys with testicular relapse.

AIMS: To determine the role of polymerase chain reaction (PCR) based minimal residual disease (MRD) detection of leukaemia specific DNA in testicular relapse in childhood acute lymphoblastic leukaemia. METHODS: DNA was obtained from archival testicular and bone marrow samples from boys with acute lymphoblastic leukaemia who relapsed in the testes. Overlapping DJH clone specific primers derived from clonal immunoglobulin heavy chain (IgH) gene rearrangement in each case were used to analyse testicular or bone marrow DNA. RESULTS: Histologically normal end of treatment testicular biopsies in the five patients in longterm remission were all MRD negative, but MRD positive in three of six boys with subsequent testicular relapse. Histologically normal bone marrow samples taken at the end of treatment were MRD negative in five of seven cases, but MRD positive in all cases at the time of isolated testicular relapse. Three boys with unilateral testicular relapse underwent unilateral orchidectomy, rather than bilateral testicular irradiation, as part of their treatment. Two of these boys were MRD positive in the histologically uninvolved testes, and both had subsequent relapses either in the testes or the bone marrow, while the MRD negative patient has not had a testicular relapse. CONCLUSIONS: The presence of MRD in testicular tissue can be assayed with a PCR based method to detect clone specific antigen receptor gene rearrangements. In this setting, PCR is more sensitive than conventional testicular histology for predicting clinical outcomes. MRD assays might be useful in the management of boys at the time of isolated testicular relapse, to confirm the presence of unilateral testicular disease.

Bone Marrow↗
PubMed1997

Improved PCR assay for the detection of antigen receptor gene rearrangements.

The detection of small numbers of leukaemia cells in patients with occult disease has important clinical implications. Leukaemia is a monoclonal disease which frequently displays clonal rearrangement of the T-cell receptor gamma (TCR gamma) and/or immunoglobulin heavy chain (IgH) gene. Clone-specific junctional sequences arising as a result of these gene rearrangements provide potentially valuable targets for monitoring residual disease by the polymerase chain reaction (PCR). However, existing strategies for PCR amplification of these clone-specific rearrangements frequently lack the necessary sensitivity or specificity, due either to the small size of the target junctional region, or to interference resulting from polyclonal IgH or TCR gamma rearrangements in normal lymphocytes. We have previously described a novel PCR strategy to overcome these obstacles which is based on the design of two overlapping clone-specific PCR primers which span the junctional region. We now describe a modification to this strategy which employs relatively short clone-specific primers which further increases the level of specificity. This new method should improve the detection of residual cells, particularly in those cases displaying small junctional regions. Unlike other strategies, specificity is generated from the initial round of amplification. This non-radioactive technique should thus prove effective in monitoring residual leukaemia in patients.

Bone Marrow↗
PubMed1997

In vivo cimetidine immunomodulatory effects on the cutaneous reaction to oxazolone in the chicken.

The effect of the histamine H2-receptor antagonist, cimetidine, on the cutaneous Arthus-like hypersensitivity to oxazolone elicited injecting subcutaneously oxazolone conjugated to egg-albumin (EA-OX) has been examined in the chicken. Cimetidine had opposite effects on the cutaneous reaction to oxazolone in relation to a different immunization schedule. Cimetidine enhanced the cutaneous reaction to oxazolone obtained immunizing chickens with oxazolone dissolved in ethanol (Eth-OX); instead cimetidine inhibited the cutaneous reaction obtained in chickens immunized with oxazolone dissolved in complete Freund adjuvant (CFA-OX). Optimum enhancement of the cutaneous arthus-like reaction to oxazolone occurred when cimetidine was given for three consecutive days starting at the immunization. The enhancing effect was absent in neonatally bursectomized chickens. Moreover, cimetidine stimulated bursal cell proliferation at day 1 after sensitization. The study of the immunoglobulin class of oxazolone antibodies produced in the immunized chickens demonstrated that cimetidine stimulated the IgM oxazolone antibody synthesis in Eth-OX immunized chickens and inhibited the IgY oxazolone antibody production in Eth-OX and total oxazolone antibody production in CFA-OX immunized chickens. The relationship between increased IgM oxazolone antibody synthesis and enhancement of the cutaneous Arthus reaction is discussed. The role of IgM antibodies in the pathogenesis of Arthus reaction in the chicken is hypothesized.

Adjuvants, Immunologic↗
PubMed1996

Covalently immobilized enzymes on biocompatible polymers for amperometric sensor applications.

Glucose oxidase or choline oxidase were covalently immobilized on the surface of 2-hydroxyethyl and glycidyl methacrylate copolymer membranes. The polymerization was induced by gamma irradiation at low temperature. The enzyme modified polymers were applied on Clark-type or platinum electrodes to form amperometric sensors based on the electrochemical measurements of oxygen or hydrogen peroxide. Glucose and choline content in standard solutions were measured and linear calibration curves were determined. The sensors studied showed a response time of less than 2 min and the observed linear ranges were increased with respect to usual biosensors owing to the diffusion-limiting effects of the membranes used. The influence of the copolymer composition on the electrochemical response and on the retained enzyme activity were explored for verifying the optimum analytical performance. The immobilized enzyme membranes stored in suitable buffers were very stable and showed a decrease up to 20% in the electrode response after 3 months of constant use.

Biocompatible Materials↗
PubMed1994

Stoichiometry of recombinant cystic fibrosis transmembrane conductance regulator in epithelial cells and its functional reconstitution into cells in vitro.

We have generated several clones of Chinese hamster ovary, mouse epitheloid C127, and pig kidney epithelial LLCPK1 cells producing high levels of functional recombinant human cystic fibrosis transmembrane conductance regulator (CFTR). Processing of CFTR to the mature and fully glycosylated form in these cells is inefficient with only approximately 40% of all newly synthesized CFTR being converted to the mature form. Furthermore, expression of the most frequent mutant allele of the cystic fibrosis (CF) gene, the delta F508 mutant in these epithelial cells, indicated that it is biosynthetically arrested at the endoplasmic reticulum and fails to traffic to the plasma membrane. Using a combination of CFTR mutants and monoclonal antibodies, all the detectable recombinant CFTR in these cells was determined at least under the conditions used, to be present as a monomer. To demonstrate the feasibility of protein replacement therapy, we were able to effect the physical transfer of functional recombinant CFTR produced in Chinese hamster ovary cells to the plasma membranes of Ha3b fibroblasts, a cell line devoid of cAMP-stimulated chloride channels. Transfer of CFTR was mediated by the hemagglutinin viral fusion protein of influenza virus present on the Ha3b cells. Efficiency of transfer was up to 25% of the target cells, and CFTR chloride channel activity was detectable for up to 12 h post-fusion. Therefore, with the development of an appropriate formulation of fusogenic proteoliposome or virosome containing reconstituted purified CFTR, it should be feasible to introduce functional CFTR into CF-affected cells.

Adenosine Triphosphate↗
PubMed1994

Glucose sensors based on enzyme immobilization onto biocompatible membranes obtained by radiation-induced polymerization.

Amperometric glucose biosensors based on glucose oxidase immobilized onto poly(2-hydroxyethylmethacrylate) membranes obtained by gamma radiation-induced polymerization were constructed. In a three-electrode configuration, smooth or platinized platinum electrodes with different shapes were used, in order to detect the amount of hydrogen peroxide produced in the glucose oxidation. A saturated calomel electrode and a platinum foil were used as a reference and counterelectrode, respectively. The biocompatible obtained sensors were characterized as regards the temperature effect, the response, and lifetime. The determination of glucose in standard solutions was carried out, and linear calibration curves were obtained. Depending on the electrode configuration, the sensor had a response time of 1-4 min, and the measuring range extended from 5 x 10(-5) to 4 x 10(-3) M.

Biosensing Techniques↗