Giovanni Pratesi

Surgical treatment of visceral artery aneurysms: A 25-year experience

OBJECTIVE The aim of this study was to analyze our 25-year experience with surgical treatment of visceral artery aneurysms (VAAs), with particular attention paid to early and long-term results. MATERIALS AND METHODS From January 1982 to September 2007, 55 patients (32 males, 58%, and 23 females, 42%) underwent surgical treatment of 59 VAAs. Only one patient was treated with an endovascular procedure. Mean patient age was 59.3 years (range, 36-78 years). The site of aneurysmal disease was splenic artery in 30 (50.8%) cases, renal artery in nine (15.2%) cases, common hepatic artery in seven (11.9%) cases, pancreaticoduodenal artery in four (6.8%) cases, celiac trunk in three (5.1%) cases, superior mesenteric artery in two (3.4%) cases, and gastroduodenal, inferior mesenteric, middle colic and right gastroepiploic in one (1.7%) case for each artery. Two (3.6%) patients had multiple VAAs. In five (9.1%) patients, an abdominal aortic aneurysm coexisted. Early results in terms of mortality and major complications were assessed. Follow-up consisted of clinical and ultrasound examinations at 1 and 12 months, and yearly thereafter. Long-term results in terms of survival and aneurysm-related complications were analyzed. RESULTS In all but two cases, elective intervention in asymptomatic patients was performed. Two (3.6%) patients had a ruptured aneurysm (one pancreaticoduodenal artery and one middle colic artery). The one perioperative death was due to an acute pancreatitis in a patient operated on for a giant inflammatory splenic artery aneurysm, yielding a perioperative mortality rate of 1.8%. Two major complications (retroperitoneal hematoma and acute pancreatitis) were recorded. Mean duration of follow-up was 82.1 months (range, 0-324 months). Estimated 10-year survival rate was 79.5%. During follow-up two aneurysm-related complications occurred, with an estimated 10-year, aneurysm-related, complication-free survival rate of 75.2%. CONCLUSION In the era of minimally invasive therapeutic approaches, elective open surgical treatment of visceral artery aneurysms is safe and effective, and offers satisfactory early and long-term results.

Hepatitis C virus RNA localization in human carotid plaques.

BACKGROUND Hepatitis C virus (HCV) infection has certain characteristics that enable it to play an important role in atherosclerosis. Some studies report its association with an increased risk of carotid artery plaque. OBJECTIVES The aim of this study was to evaluate the presence of HCV genomic sequences and replicative intermediates in plaque tissues. STUDY DESIGN A cohort of consecutive, prospectively recruited patients with HCV infection and chronic ischemic heart disease from the Cardiology, Vascular Surgery and Hepatology Units of a University Hospital in Florence, Italy, were studied. RESULTS Positive-strand HCV RNA was detected in seven carotid plaque tissues from anti-HCV-positive patients and was not detected in the nine carotid plaque tissues obtained from anti-HCV-negative patients. In three patients, HCV RNA was found in carotid plaque and not in serum. HCV replicative intermediates were detected in three plaque samples. Direct sequencing of HCV RNA from the plaque and serum showed HCV genotypes 2 (five cases) and 1 (two cases). CONCLUSIONS The novel finding of HCV RNA sequences in plaque tissue strongly suggests an active local infection. This in turn makes it conceivable that the virus may exert local action in carotid atherosclerosis.

High levels of homocysteine, lipoprotein (a) and plasminogen activator inhibitor-1 are present in patients with abdominal aortic aneurysm

Over the last few years,there has been increasing interest in the investigation of the pathogenesis of AAA, and a role for some novel risk factors, in particular thrombophilic risk factors, has been suggested. The aim of this study was to evaluate a number of thrombophilic parameters in a large group of patients with AAA. In 438 patients with AAA, and in 438 healthy subjects, selected to be comparable for age and gender with patients and without instrumental evidence of AAA, a pattern of thrombophilic parameters [homocysteine (Hcy), lipoprotein (a) [Lp(a)], plasminogen activator inhibitor-1 (PAI-1), anticardiolipin antibodies (ACA), MTHFR C677T polymorphism, prothrombin gene G20210A variant and FactorV Leiden mutation] has been evaluated. A significant difference for Hcy, PAI-1 and Lp(a) plasma levels has been observed between patients and controls. After adjustment for the traditional cardiovascular risk factors, a significant increased risk of having AAA has been observed for high levels of Hcy (OR: 7.8; p<0.0001), Lp(a) (OR: 2.4; p<0.0001) and PAI-1 (OR: 3.2; p<0.0001). The association has been confirmed after exclusion of patients with other localization of atherosclerosis. Moreover, a significant association between larger abdominal aortic diameters and the number of thrombophilic parameters has been reported (r = 0.13; p = 0.005). In conclusion, a significant association between abnormal levels of some metabolic parameters related to thrombosis such as Hcy, Lp(a) and PAI-1 and AAA has been observed.

Iron local structure in tektites and impact glasses by extended X-ray absorption fine structure and high-resolution X-ray absorption near-edge structure spectroscopy

Abstract The local structure of iron in three tektites has been studied by means of Fe K-edge extended X-ray absorption fine structure (EXAFS) and high-resolution X-ray absorption near-edge structure (XANES) spectroscopy in order to provide quantitative data on distance and Fe coordination number. The samples studied are a moldavite and two australasian tektites. Fe model compounds with known Fe oxidation state and coordination number were used as standards in order to extract structural information from the XANES pre-edge peak. EXAFS-derived grand mean distances and Fe coordination numbers for the three tektite samples are constant within the estimated error ( =2.00 A ± 0.02 A, CN = 4.0 ± 0.4). In contrast to other data from the literature on Fe-bearing silicate glasses, the tektites spectra could not be fitted with a single Fe-O distance, but rather were fit with two independent distances (2 × 1.92 A and 2 × 2.08 A). High-resolution XANES spectra of the three tektites display a pre-edge peak whose intensity is intermediate between those of staurolite and grandidierite, thus suggesting a mean coordination number intermediate between 4 and 5. Combining the EXAFS and XANES data for Fe, we infer the mean coordination number to be close to 4.5. Comparison of the tektites XANES spectra with those of a suite of different impact glasses clearly shows that tektites display a relatively narrow range of Fe oxidation state and coordination numbers, whereas impact glasses data span a much wider range of Fe oxidation states (from divalent to trivalent) and coordination numbers (from tetra-coordinated to esa-coordinated). These data suggest that the tektite production process is very similar for all the known strewn fields, whereas impact glasses can experience a wide variety of different temperature–pressure–oxygen fugacity conditions, leading to different Fe local structure in the resulting glasses. These data could be of aid in discriminating between tektite-like impact glasses and impact glasses sensu strictu.

Genetic analysis of 56 polymorphisms in 17 genes involved in methionine metabolism in patients with abdominal aortic aneurysm

Background: Previous studies suggested an association between abdominal aortic aneurysm (AAA) and hyperhomocysteinaemia, a complex trait determined by genetic and environmental factors. Our hypothesis was that polymorphisms in genes directly or indirectly involved in methionine metabolism may contribute to AAA susceptibility. Method: We studied 56 polymorphisms in MTHFR, MTR, MTRR, CBS, MTHFD1, SLC19A1, NNMT, TCN2, AHCY, BHMT, BHMT2, FOLH1, TYMS, ENOSF1, SHMT1, PON1, PON2 genes according to their demonstrated/putative function, localisation in promoter or regulatory and coding regions and/or heterozygosity values >0.300. Polymorphisms were evaluated by using a primer extension based microarray technology in 423 AAA patients and 423 matched controls. Results: All polymorphisms resulted in Hardy–Weinberg equilibrium in patients and controls. At the multiple logistic regression analysis adjusted for traditional cardiovascular risk factors (sex, age, hypertension, smoking habit, dyslipidaemia, diabetes) and chronic obstructive pulmonary disease (COPD), rs8003379 MTHFD1 (odds ratio (OR) 0.41, 95% confidence interval (CI) 0.26 to 0.65) and rs326118 MTRR (OR 0.47, 95% CI 0.29 to 0.77) polymorphisms resulted in independent susceptibility factor for AAA. Conclusions: After haplotype reconstruction, logistic regression analyses adjusted for traditional risk factors and COPD showed a significant association among AAA and AHCY, FOLH1, MTHFD1, MTR, NNMT, PON1 and TYMS haplotypes. Our findings offer new insights into the pathogenesis of AAA.

Light-induced variations in realgar and beta -As 4 S 4 ; X-ray diffraction and Raman studies

Abstract Transformations induced by light in realgar and β-As4S4 have been studied by means of X-ray diffraction (powder and single-crystal) and Raman laser spectroscopy. Both polychromatic and monochromatic light alter realgar and the β phase into pararealgar. By lowering the reaction rate (long-wavelength pass filter, low laser power) an intermediate product, corresponding to the so-called “χ phase,” can be observed during the alteration process from β-As4S4 to pararealgar (polychromatic filtered light and laser light) and that from realgar to pararealgar (only with polychromatic filtered light). The powder pattern of the χ phase is fairly similar to that of β-As4S4 but differs from realgar, and it can be indexed on the basis of an expanded β-phase unit cell. Lattice parameters are as follows: a = 9.758(5), b = 9.522(5), c = 9.074(5) Å, 0 = 100.84(5)°, and a = 9.757(4), b = 9.512(7), c = 9.089(4) Å, 0 = 100.97(3)° for the χ phase obtained from alteration of realgar and β-As4S4, respectively. The formation of the χ phase is preceded by a strong anisotropic increase of the unit-cell volume of realgar and the β phase. The effects of light exposure on lattice parameters were studied using single-crystal X-ray diffraction: In realgar a and c sin β increase linearly with increasing exposure times, whereas b remains substantially unchanged. In the β-As4S4 crystals, b and c sin β increase while a decreases so that, after 1560 min, the unit-cell dimensions match those of the χ phase. Raman spectroscopy, which allows monitoring of the alteration process in real time, indicates the presence of the same As4S4 cage molecule in the χ phase as in realgar and β -As4S4 and confirms the similarity between the structure of χ and that of β. However, a less-ordered crystal structure and a lower molecular symmetry is suggested from analysis of the spectroscopic results.

Spectroscopic investigation and normal mode analysis of As4S4 polymorphs

Abstract Tetra-arsenic tetrasulfide polymorphs have been investigated by IR, Raman and UV-visible spectroscopies. The mineral realgar ( α -As 4 S 4 ) and the high-temperature phase β -As 4 S 4 transform to pararealgar by exposure to monochromatic laser light with a reaction rate depending on the wavelength of the exciting radiation. The photoinduced alteration process has been monitored by Raman spectroscopy, following in real time the spectral changes of the samples undergoing irradiation. A satisfactory assignment of realgar, β -As 4 S 4 and pararealgar was obtained by employing a simplified valence force field which provided a complete set of normal coordinates suitable for describing the vibrational spectra of these As 4 S 4 polymorphs.

HCV infection facilitates asymptomatic carotid atherosclerosis: preliminary report of HCV RNA localization in human carotid plaques

BACKGROUND Clinical and experimental evidence suggests that hepatitis C virus (HCV) infection shows peculiar characteristics that strongly support a role in the development of atherosclerosis. We aimed to investigate whether (a) HCV infection can facilitate asymptomatic carotid lesions and (b) the presence of HCV RNA sequences can be shown in plaque tissues. METHODS The status of carotid arteries, studied as intima-media thickness (IMT) in carotid bifurcation and prevalence and severity of plaques in internal carotid artery, was investigated by high-resolution B-mode ultrasonography in 31 HCV seropositive (HCV+) and in 120 age-matched HCV seronegative (HCV-) subjects evaluated for cardiovascular risk factors. The atherosclerotic risk profile, inflammation markers and main liver function tests were also studied in all patients. HCV RNA sequences were investigated by highly sensitive reverse transcriptase-polymerase chain reaction (RT-PCR) in plaque tissues and serum of 2 HCV+ patients who underwent carotid revascularization. RESULTS Genomic and antigenomic HCV RNA strands were evidenced within both the carotid plaque tissues examined. The prevalence of an IMT > 1 mm, but not the prevalence and severity of internal carotid plaques, was significantly higher (P < 0.001) in HCV+ than in HCV patients. The atherosclerotic risk profile for traditional and inflammatory factors did not differ between the HCV+ and HCV- groups. Main liver function tests did not differ between the two groups. HCV positivity was significantly associated with >1 mm IMT (P < 0.01) according to univariate analysis, and this association remained significant in multivariate regression analysis. CONCLUSIONS The novel finding of HCV RNA sequences within carotid plaques suggests a local pro-atherogenetic action of the virus inside the plaque. On the whole our data strongly support that HCV infection facilitates the occurrence of carotid atherosclerotic lesions.

SERS, XPS, and DFT Study of Adenine Adsorption on Silver and Gold Surfaces

The adsorption of adenine on silver and gold surfaces has been investigated combining density functional theory calculations with surface-enhanced Raman scattering and angle-resolved X-ray photoelectron spectroscopy measurements, obtaining useful insight into the orientation and interaction of the nucleobase with the metal surfaces.

The crystal structure of pararealgar, AS4S4

Gillulyite, TI2(AsH ,SbH )8S13,is monoclinic with space group P2/n and a = 9.584(3), b = 5.679(2), c = 21.501(6) A, ~ = 100.07(2)°, V = 1152.2(7) A3, and Z = 2, The average structure was determined using direct methods and refined to a final residual of 0.046 using 930 reflections. The structure consists of TI-As-Sand As-S-bearing sheets, each present statistically 50% of the time. Four sheets, linked together by Tl-S, As-S, and S-S bonds, are stacked parallel to (00 I), yielding the 21-A c-axis repeat of the average unit cell. The Tll atom within the TI-As-S sheet is coordinated by six S nearest neighbors, which form a distorted trigonal prism. The partially occupied Tl2 position between the sheets is split symmetrically about the twofold axis with a separation of 1.28 A and equal but partial occupancies of25%. The disordering of the Tl2 position and extreme distortion of its coordination polyhedron is probably the result of the Tl+ 6s2 lone pair effect. The mean bond distances for the AsS3pyramids range from 2.263 to 2.319 A. However, four of five pyramids have a fourth S neighbor at distances ranging from 2.943 to 3.001 A, which may be rationalized in terms of the AsH 4s210ne pair effect. Edge sharing among the AsS3pyramids results in an As-As distance of 2.562 A, comparable with that observed in elemental As. The presence of S-S and As-As bonding suggests that gillulyite might more appropriately be classified as a sulfide rather than a sulfosalt. The new mineral gillulyite, TI2(As,Sb)8SI3" one of several unusual Tl minerals found in the Mercur gold deposit, Utah, was reported by Wilson et al. (1991) to be a new thallium arsenic sulfosalt. The details of the occurrence, composition, optical and physical properties, and powder difITaction and unit-cell data are presented in this earlier work. This paper presents the results of a structural investigation of this unusual mineral. tions were too weak to be measured and suggest minor ordering in the b direction that was not investigated. Systematic absences indicate the space group to be Pn or P2/n. Intensity statistics support the latter choice, which was confirmed by the successful solution and refinement of the structure. The severe effects of absorption were corrected by the empirical "II-scan method. Direct methods produced solutions that showed what appeared to be AsS3 groups in a linked pattern, but the expected large peaks representing the Tl atoms were absent; thus, these solutions were considered to be false. Only after many STRUCTIJRE DETERMINATION AND REFINEMENT attempts with various direct and heavy atom methods After considerable searching, an irregular fragment of were we able to decipher the highly disordered average gillulyite was found that produced relatively narrow and structure described below, with its partially occupied As, symmetrical diffraction maxima. A hemisphere of data S, and Tl positions. In hindsight, we realize that the direct was collected and averaged to yield a more accurate data methods program Mithril (Gilmore, 1984) had produced set. A scan speed of 6°/min (in w) was used. Weak refleccorrect locations for most of the atoms early in the structions [/<IO.OO[] were rescanned (maximum of two reture determination process, but we were initially unwillscans) and the counts accumulated to improve accuracy. ing to accept them. The remaining atomic sites were found Experimental details are given in Table l. by difference-Fourier syntheses. Examination of a series of precession photographs conFull-matrix, least-squares refinement was performed to firmed the cell parameters and revealed a weak zone of minimize ~ w(IFaI IFe I)2. All computer programs used diffuse and split reflections in the b* direction, which efwere from Texsan (Molecular Structure Corporation, fectively doubles the length of the b axis. These reflec1985). Atomic scattering factors and anomalous disper0003-004X/95/0304-0394