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Biomedical subjects

A Napoli

Publications and source records attributed to A Napoli.

At least 19 recordsLinked to original sources
PubMed2006

Volumetric evaluation of therapy response in patients with lung metastases. Preliminary results with a computer system (CAD) and comparison with unidimensional measurements.

PURPOSE: The aim of this study was to assess the efficacy of a Computer-Aided Detection (CAD) system in the identification of lung metastases and to compare the volumetric CAD measurements with unidimensional observer measurements in the evaluation of treatment response in oncology patients. MATERIALS AND METHODS: Two observers (A and B) evaluated nine patients undergoing lung computed tomography (CT) just before and immediately after treatment with chemotherapy. Multislice CT scans were performed before and after the injection of contrast material with a high-resolution protocol (collimation 4x1 mm, 100 mAs, 120 kV). Response Evaluation Criteria in Solid Tumours (RECIST) criteria were used to consider the disease as stable, increased or decreased. Subsequently, target lesions (most significant lesions identified before and after chemotherapy) were evaluated with a computerised system (CAD) to establish volumetric measurements. Observers' unidimensional measurements and CAD volumetric measurements were analysed for comparison. RESULTS: Twenty-four nodules (diameter: 5-18 mm in the first study and 4-20 mm in the follow-up study) were included. Observers agreed in the assessment of therapy response in 21 nodules: eight were considered to have increased in size, and 13 were judged stable. Observer and CAD measurements disagreed in three nodules: two were considered stable by radiologists and increased by CAD; one was considered increased by radiologists and stable by CAD.As regards patient response, radiologists disagreed in two cases. CAD and observers did not agree in one case. CONCLUSIONS: Our preliminary data suggest that volumetric measurements can modify the diagnostic and therapeutic evaluation of oncology patients under chemotherapy.CAD volumetric measurements allow an easy and objective evaluation, reducing interobserver variability in the evaluation of chemotherapy response.

Adult↗
PubMed2006

Multidetector-row CT angiography of renal artery stenosis in 50 consecutive patients: prospective interobserver comparison with DSA.

PURPOSE: The purpose of this study was to establish the diagnostic value of multidetector-row computed tomography (MDCT) angiography compared with digital subtraction angiography (DSA) for detection and quantification of both main and accessory renal artery stenosis in patients with secondary hypertension. MATERIALS AND METHODS: Fifty consecutive patients scheduled for DSA were considered candidates for MDCT angiography. In all patients, MDCT angiography of the abdominal aorta was performed before DSA. For the purpose of interpretation, the arteries were separately interpreted either with DSA or MDCT angiography in order to provide qualitative and quantitative information. For qualitative evaluation, one experienced reader graded the opacification of renal arteries as excellent, good or poor; for quantitative evaluation, MDCT and DSA were independently evaluated for the number of renal arteries and the presence, location and degree of stenosis in random order by three readers. On the basis of consensus readings, calculations of sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) for detection of degree of stenosis were made by using DSA findings as the standard of reference. Interobserver variability was also assessed. RESULTS: With regard to qualitative analysis, arterial enhancement was considered excellent in 39 patients and good in 11. For quantitative analysis, 73 arteries were classified as normal with DSA. Although 72 of these were also classified as normal with CT angiography, one was overestimated by one grade; at DSA, 16 arteries were classified as moderately stenotic; in two arteries, there was an overestimation of one grade. Perfect correlation was achieved for the diagnosis of occlusion. In two patients, all three readers detected multiple severe stenoses on both modalities, with a "string-of-beads" appearance typical of fibromuscular dysplasia. Accessory arteries were correctly identified as such by all three readers on either DSA or MDCT. Levels of sensitivity, specificity and accuracy regarding degree of stenosis were 100%, 98.6% and 96.9%, respectively, with PPV and NPV of 97.6% and 100%, respectively. When we considered significant arterial stenosis (50%-100% luminal narrowing), sensitivity, specificity and accuracy were 100%, 97.3% and 97.8%, respectively, with a PPV and NPV of 98.2% and 97.8%, respectively. For all observers, interobserver agreement was almost perfect (k=0.81-1) for both MDCT and DSA, with a k value between 0.82 and 0.95. CONCLUSIONS: MDCT angiography is very accurate and robust, even for the assessment of renal artery stenosis, and has the potential to become a viable substitute, in most cases, for diagnostic catheter-based DSA.

Adult↗
PubMed2005

Coherent control of stimulated emission inside one-dimensional photonic crystals.

In this paper, the quasinormal mode (QNM) theory is applied to discuss the quantum problem of an atom embedded inside a one-dimensional (1D) photonic band gap (PBG) cavity pumped by two counterpropagating laser beams. The e.m. field is quantized in terms of the QNMs in the 1D PBG and the atom modeled as a two-level system is assumed to be weakly coupled to just one of the QNMs. The main result of the paper is that the decay time depends on the position of the dipole inside the cavity, and can be controlled by the phase difference of the two laser beams.

Journal Article↗
PubMed2005

Contraception in diabetic women: an Italian study.

Over 1 year, a survey on contraception and obstetric history was performed on a cohort of 667 Caucasian fertile diabetic women (446, type 1 and 201, type 2) living in Italy. RESULTS: Of these women, 30.4% used hormonal contraceptives, 12.0% intra-uterine device (IUD), 10.7% declared they used no contraception, 47.0% only utilised barrier and/or natural methods. However, irrespective of their previous contraceptive strategy, 7.2% of all the studied population was surgically sterilized during caesarean section. HORMONAL CONTRACEPTION: Of these women, 60.4% was prescribed by a gynaecologist, 11.2% by a diabetologist, 15% by both of them and 13.4% by others. The proportion using oral contraception was similar among types 1 and 2 women (29.4% versus 27.8%, chi(2) = ns). SMOKING HABITS: Of women taking hormonal contraception, 30.0% were smokers. EDUCATIONAL LEVEL: University graduates (37.1%), high school leaves (32.2%), secondary school (28.2%) and primary school leaves (15.5%) used oral contraceptives (OC). OBSTETRIC HISTORY: The mean number of deliveries was 1.14 +/- 1.1, of miscarriages was 1.3 +/- 0.7 and of induced abortions 0.17 +/- 0.5. Planning of at least one pregnancy was reported in 29.4% of patients.

Adult↗
PubMed2005

A lower level of entropy in circadian rhythm of the sinus R-R intervals suggests a prevalence of the cardiac sympathetic regulation in early physiological pregnancy.

The study estimates the unpredictable disorder (chaos) within the 24 h pattern of sinus R-R intervals (SRRI) in clinically healthy pregnant women (CHPW) and clinically healthy non-pregnant women (CHNPW), in order to evaluate the early gestational changes in neurovegetative cardiac pacing. SRRI were provided by the 24-h Holter ECG of 10 CHPW and 10 CHNPW. SRRI were investigated by descriptive conventional statistics by means of the Time and Frequency Domain Analysis, and subsequently, in their chaotic component by means of entropy analysis. Both the SRRI and entropy were tested via the Cosinor method to better decipher whether or not the periodic disorder in heart rate variability is modified in pregnancy as a result of a gestational tonic resetting of the cardiac sympatho-vagal regulation. Cosinor analysis documented that the circadian rhythm of both the SRRI and entropy were preserved in CHNPW and CHPW. However, the circadian rhythm of SRRI and entropy in CHPW exhibited a significantly decreased 24 h mean. Via the analysis of the rhythmicity of entropy, this study has documented that the chaos in the 24 h pattern of SRRI is less prominent in CHPW than in CHNPW. Such a reduction of level in the deterministic periodic chaos of heart rate variability provides evidence that, in early pregnancy, a tonic elevation of the sympathetic activity regulates cardiac pacing.

Adult↗
PubMed2005

PPS-PEG surface coating to reduce thrombogenicity of small diameter ePTFE vascular grafts.

AIMS: Patency failure of small vascular synthetic grafts is still a major problem for coronary and peripheral revascularization. Thus, three new surface coatings of small synthetic grafts were tested in an acute pig model to evaluate their thrombogenicity (extracorporeal arterio-venous shunt) and in a chronic rat model to evaluate the tissue reaction they induced (subcutaneous implantation). METHODS: In five domestic pigs (25-30 kg) an extracorporeal femoro-femoral arterio-venous shunt model was used. The study protocol included first a non-heparinized perfusion sequence followed by graft perfusion after 10,000 UI iv heparin. Grafts were perfused for 3 and 9 minutes. The following coatings were tested on ePTFE grafts: poly-propylene sulphide (PPS)--poly-ethylene glycol (PEG) (wet and dry applications) as well as carbon. Two sets of control were used, one dry and one wet (vehicle only). After perfusion grafts were examined by scanning electron microscopy for semi-quantitative assessment (score 0-3) of cellular and microthrombi deposition. To assess tissue compatibility, pieces of each material were implanted subcutaneously in 16 Wistar rats. At 2, 4, 8, 12 weeks four animals each were sacrificed for semi-quantitative (score 0-3) histologic evaluation of tissue reaction. RESULTS: In the pig model, cellular deposition and microthrombi formation increased over time. In non- heparinized animals, the coatings did not improve the surface characteristics, since they did not prevent microthrombi formation and cellular deposition. In heparinized animals, thrombogenicity was lowest in coated grafts,especially in PPS -PEG dry (p<0.05), and highest in controls. Cell deposition was lowest in PPS-PEG dry, but this difference was not statistically significant vs.controls. In the rat model,no significant differences of the tissue reaction could be shown between materials. CONCLUSION: While all coatings failed to add any benefit for lowering tissue reaction, surface coating with PPS -PEG (dry application) reduced thrombogenicity significantly (in heparinized animals) and thus appears to be promising for improving graft patency of small synthetic vascular prostheses.

Animals↗
PubMed2004

Second quantization and atomic spontaneous emission inside one-dimensional photonic crystals via a quasinormal-modes approach.

An extension of the second quantization scheme based on the quasinormal-modes theory to one-dimensional photonic band gap (PBG) structures is discussed. Such structures, treated as double open optical cavities, are studied as part of a compound closed system including the electromagnetic radiative external bath. The electromagnetic field inside the photonic crystal is successfully represented by a new class of modes called quasinormal modes. Starting from this representation we introduce the Feynman's propagator to calculate the decay rate of a dipole inside a PBG structure, related to the density of modes, in the presence of the vacuum fluctuations outside the one-dimensional cavity.

Journal Article↗
PubMed2003

High-resolution multidetector CT in the preoperative evaluation of patients with renal cell carcinoma.

OBJECTIVE: The purpose of our study was to evaluate the accuracy of multidetector CT (MDCT) using a high-resolution protocol in the preoperative assessment of patients with renal cell carcinoma who are possible candidates for nephron-sparing surgery. MATERIALS AND METHODS: Forty patients with suspected renal cell carcinoma underwent MDCT. Contrast-enhanced acquisitions were obtained during arterial, nephrographic, and urographic phases using a thin-slice protocol. One-millimeter-thick source images were evaluated by two observers on a dedicated workstation for the identification and characterization of the tumor, presence of a pseudocapsule or invasion of perirenal fat, involvement of adrenal glands or surrounding tissues, presence of satellite lesions within Gerota's fascia, infiltration of renal vein and inferior vena cava, involvement of lymph nodes, and presence of distant metastases. Imaging findings were compared with surgical specimens using criteria from the Robson and TNM classification systems. RESULTS: The presence and size of all lesions were correctly shown in all patients. In evaluating Robson stage I of renal cell carcinoma, we were able to diagnose fat infiltration on 1-mm scans with 96% sensitivity, 93% specificity, and 95% accuracy; the positive and negative predictive values were, respectively, 100% and 93%. One hundred percent accuracy was achieved in staging high-grade lesions. CONCLUSION: High-resolution MDCT is accurate in the preoperative evaluation of patients with renal cell carcinoma.

Adult↗
PubMed2002

Poly(ethylene glycol) block copolymers.

The ubiquitous use of poly(ethylene glycol) in the biomaterials field has also boosted the research activity in the chemical derivatization of this polymer. We focused our interest on the preparation of tailor-made poly(ethylene glycol)-based structures and on the study of structure-activity relationships for its functionalization, as preliminary steps for the preparation of smart functional materials. More specifically, amphiphilic and cationic block copolymers were prepared for prospective use in the preparation of self-assembled carriers, and Michael-type addition of thiols onto acrylates was studied as a model for end-group reaction leading to hydrogel formation.

Binding Sites↗
PubMed2002

Comparative investigation of the surface properties of commercial titanium dental implants. Part I: chemical composition.

The surfaces of five commercially available titanium implants (Brånemark Nobel Biocare, 3i ICE, 3i OSSEOTITE, ITI-TPS, and ITI-SLA) were compared by scanning electron microscopy, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectroscopy. All five implant types were screw-shaped and fabricated from commercially pure (cp) titanium, but their surface properties differed both as regards surface morphology and surface chemical composition. The macro- and microstructure of the implant surfaces were investigated by scanning electron microscopy. The surfaces chemical composition was determined using the surface-sensitive analytical techniques of X-ray photoelectron spectroscopy and time-of-flight secondary ion spectrometry. Surface topographies were found to reflect the type of mechanical/chemical fabrication procedures applied by the manufacturers. The titanium oxide (passive) layer thickness was similar (5-6 nm) and typical for oxide films grown at or near room temperature. A variety of elements and chemical compounds not related to the metal composition were found on some implant types. They ranged from inorganic material such as sodium chloride to specific organic compounds believed to be due to contamination during fabrication or storage. The experimental findings are believed to make a contribution to a better understanding of the interplay between industrial fabrication procedure and physico-chemical implant surface properties.

Journal Article↗
PubMed2001

Clinical presentation of inhalational anthrax following bioterrorism exposure: report of 2 surviving patients.

The use of anthrax as a weapon of biological terrorism has moved from theory to reality in recent weeks. Following processing of a letter containing anthrax spores that had been mailed to a US senator, 5 cases of inhalational anthrax have occurred among postal workers employed at a major postal facility in Washington, DC. This report details the clinical presentation, diagnostic workup, and initial therapy of 2 of these patients. The clinical course is in some ways different from what has been described as the classic pattern for inhalational anthrax. One patient developed low-grade fever, chills, cough, and malaise 3 days prior to admission, and then progressive dyspnea and cough productive of blood-tinged sputum on the day of admission. The other patient developed progressively worsening headache of 3 days' duration, along with nausea, chills, and night sweats, but no respiratory symptoms, on the day of admission. Both patients had abnormal findings on chest radiographs. Non-contrast-enhanced computed tomography of the chest showing mediastinal adenopathy led to a presumptive diagnosis of inhalational anthrax in both cases. The diagnoses were confirmed by blood cultures and polymerase chain reaction testing. Treatment with antibiotics, including intravenous ciprofloxacin, rifampin, and clindamycin, and supportive therapy appears to have slowed the progression of inhalational anthrax and has resulted to date in survival.

Anthrax↗
PubMed2001

Facile approach to enantiomerically pure alpha-amino ketones by Friedel-Crafts aminoacylation and their conversion into peptidyl ketones.

In this article we describe a versatile and straightforward preparative approach to chiral aryl alpha-amino ketones via a Friedel-Crafts-type reaction of stable and enantiomerically pure N-Fmoc protected L-amino acid chlorides with toluene in the presence of aluminum trichloride. The developed methodology provided aryl alpha-amino-p-methylphenyl ketones, which can be obtained and isolated as free bases or recovered as their N-acetyl derivatives, after treatment with acetic anhydride in chloroform at room temperature, subsequent to the Lewis acid induced removal of the 9-fluorenylmethoxycarbonyl protecting group. The Friedel-Crafts-like process and the cleavage of the amino function masking group can selectively be performed since, as verified in all cases, the alpha-aminoacylation step occurred with kinetics that were faster than those required to remove the N-protection. The presented approach was also explored as a facile and useful synthetic tool for the preparation of optically pure ketone di- and tripeptides. These compounds can be obtained in exceptionally overall yields without need of chromatographic purification. Moreover, either aryl alpha-amino ketones or modified di- and tripeptides, in all cases, can be isolated in very high chemical and optical purity without recourse to resolution of diastereomeric mixtures, since the chiralities of the asymmetric amino acid educts were completely conserved throughout the entire process.

Dipeptides↗
PubMed2001

Site selectivity in the synthesis of O-methylated hydroxamic acids with diazomethane.

In this paper we report the results obtained by treating some selected hydroxamic acids with diazomethane in ethereal media. The multitask reagent diazomethane was used either as a base to induce deprotonation of the chosen hydroxamic acids or as conjugated acid which undergoes one-pot methylation processes of the generated anions. Product distributions clearly showed that a high site selectivity is expressed by the different deprotonated species in the alkylation processes. Under the adopted conditions, the prevalent site of methylation is in all the cases the oxygen of the hydroxamic acid. While in aliphatic hydroxamic acids only O-alkylation is observed, in the aromatic substrates, the NH group competes with the OH function as the nucleophilic site, although the OH reactivity still dominates.

Diazomethane↗
PubMed2001

A novel member of the bacterial-archaeal regulator family is a nonspecific dna-binding protein and induces positive supercoiling.

In hyperthermophilic Archaea genomic DNA is from relaxed to positively supercoiled in vivo because of the action of the enzyme reverse gyrase, and this peculiarity is believed to be related to stabilization of DNA against denaturation. We report the identification and characterization of Smj12, a novel protein of Sulfolobus solfataricus, which is homologous to members of the so-called Bacterial-Archaeal family of regulators, found in multiple copies in Eubacteria and Archaea. Whereas other members of the family are sequence-specific DNA- binding proteins and have been implicated in transcriptional regulation, Smj12 is a nonspecific DNA-binding protein that stabilizes the double helix and induces positive supercoiling. Smj12 is not abundant, suggesting that it is not a general architectural protein, but rather has a specialized function and/or localization. Smj12 is the first protein with the described features identified in Archaea and might participate in control of superhelicity during DNA transactions.

Amino Acid Sequence↗
PubMed2001

Structural characterization of isoxazolidinyl nucleosides by fast atom bombardment tandem mass spectrometry.

4'-Aza-2',3'-dideoxyerythrofuranosyl derivatives of thymine (AdT, 1) and uracil (AdU, 2) are analogues of 2',3'-dideoxyribofuranosyl thymine (ddT, 3) and uracyl (ddU, 4). Compounds 1 and 2 are representative of a new class of antiviral agents where the sugar moiety is replaced by an isoxazolidine ring. The increasing importance of isoxazolidinyl nucleosides has encouraged the exploitation of simple mass spectrometric rules for unambiguously assigning their structure. The species 1, 2, 5 and 6 were therefore synthesized in order to evaluate the role of the basic centre of the modified sugar moiety in their gas-phase chemistry. The tandem mass spectra of these compounds are similar to those of the wild-type nucleosides and display fragment ions corresponding to [B + 2H](+),[M - BH](+) and [B + 27](+) species, where B is the nucleobase. The last species derives from a retrocycloaddition process which is less evident in 2'-deoxyribosides. This behaviour is consistent with protonation of the analytes at the pyrimidine rings. Model isoxazolidines, in which the nucleobase was replaced by a phenyl or a naphthyl moiety, displayed the expected behaviour of species with a localized charge on the N-O moiety of the isoxazolidine ring.

Antiviral Agents↗
PubMed2001

Electron transfer vs. proton transfer within radical-cation clusters of guanosine and deoxyguanosine with substituted naphthalenes and sinapinic acid.

Guanosine (G) and deoxyguanosine (dG) radical cations can be generated in the gas phase by single electron transfer (SET) within nucleoside-dimethoxynaphthalenes (1-2) electron-bound heterodimers produced by fast atom bombardment in a four sector mass spectrometer. The nucleobase guanine is much more easily oxidized when it is linked to a ribose moiety. The radical cation dimers formed by G and dG with sinapinic acid behave as proton-bound heterodimers. The experiments mimic to some extent the migration of radical sites within stacking bases which causes DNA damaging through depurination processes.

Cations↗
PubMed2001

Transforming growth factor-beta 1 and insulin-like growth factor-1 expression in ovarian endometriotic cysts: a preliminary study.

Increased concentrations of TGF-beta 1 in endometriotic tissue are considered important in the pathophysiology of endometrial diseases since TGF-beta 1 may inhibit natural killer activity and induce angiogenesis and proliferation of endometrial stromal cells. In the present study we report on TGF-beta 1, IGF-1 and their receptor localization, as detected by Northern hybridization and immunohistochemistry, in ovarian endometriotic tissues removed during surgical procedures. We detected comparable expression of IGF-1 and IGF-1 receptor in the stromal and epithelial compartments, thus confirming disregulated expression of the IGF system in ovarian endometriosis. On the contrary, strongly increased TGF-beta 1 steady state level mRNA expression was detected in all endometriotic samples. In addition, we demonstrated weak TGF-beta 1 immunohistochemical expression in the epithelial lining and intense expression in the cellular stroma of ovarian endometriomas, thus suggesting that TGF-beta 1 could have an important role in the maintenance and propagation of the disease. On the basis of these preliminary results we can assume that TGF-beta 1, IGF-1 and their receptors may play an important role in the pathogenesis of endometriosis.

Adult↗