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R Chiesa

Publications and source records attributed to R Chiesa.

At least 91 records · Page 5Linked to original sources
PubMed1997

Is endoscopy useful for early diagnosis of ischaemic colitis after aortic surgery? Results of a prospective trial.

BACKGROUND: Ischaemic colitis is an infrequent, but potentially fatal, complication of abdominal aortic surgery. Its presentation is often underestimated on account of a paucity of symptoms, thus the real incidence of ischaemic colitis may be higher. AIM: To determine the prognostic value and sensitivity of endoscopy, early postoperative endoscopic findings were evaluated. METHODS: Over a period of three years a prospective study was undertaken in a consecutive series of 105 patients (mean age 68.9 years, range 51-85) undergoing routine rectosigmoidoscopy within 72 hours of aortic reconstructive surgery. RESULTS: Colonic ischaemia was found in 12 patients (11.4%); five had endoscopic evidence of mild ischaemic colitis, ulcerations were identified in five and diffuse superficial necrosis in two. Seven of the 12 patients were symptomatic. Laparotomy was never deemed necessary and all patients were successfully treated with a conservative regimen. There were no deaths. Elective reconstruction or urgent procedure did not correlate with the development of colonic ischaemia, nor did duration of aortic cross-clamp time, patency of the inferior mesenteric artery and its possible ligation or reimplantation or patency of the hypogastric arteries. CONCLUSIONS: Rectosigmoidoscopy is effective for early diagnosis of ischaemic colitis. Early endoscopy should be routinely performed only for patients in whom impaired blood flow is suspected on the basis of the intraoperative objective assessment of the colon and in presence of symptoms.

Aged↗
PubMed1996

Activation effects of a prion protein fragment [PrP-(106-126)] on human leucocytes.

Prion-related encephalopathies are characterized by the intracerebral accumulation of an abnormal isoform of the cellular prion protein (PrPC) named scrapie prion protein (PrPSc). The pathological forms of this protein and its cellular precursor are not only expressed in the brain but also, at lower concentrations, in peripheral tissues. We recently showed that a synthetic peptide corresponding to residues 106-126 [PrP-(106-126)] of the human PrP is toxic to neurons and trophic to astrocytes in vitro. Our experiments were aimed at verifying whether PrP-(106-126) and other peptides corresponding to fragments of the amyloid protein purified from brains of patients with Gerstmann-Sträussler-Scheinker disease-namely PrP-(89-106), PrP-(106-114), PrP-(127-147)-were capable of stimulating circulating leucocytes. Native PrP expression in human lymphocytes, monocytes and neutrophils was first confirmed using PCR amplification of total RNA, after reverse transcription, and immunoblot analysis of cell extracts with anti-PrP antibodies. PrP-(106-126), but not the other peptides, increased membrane microviscosity, intracellular Ca2+ concentration and cell migration in circulating leucocytes, and O2-. production in monocytes and neutrophils. Membrane microviscosity was determined by the fluorescence polarization technique, using diphenylhexatriene as a probe, 300 s after the addition of PrP-(106-126) to the cell suspension in the concentration range 5-50 microM. The increase in intracellular Ca2+ elicited by PrP-(106-126) was dose-dependent in the range 5-500 microM. PrP-(106-126) stimulated O2-. production in monocytes and neutrophils in a dose- (10-300 microM) and time-(5-30 min) dependent manner in the presence of 10 microM dihydrocytochalasin B. Both the increase in Ca2+ concentration and the O2-. production were partially sensitive to pertussis toxin. PrP-(106-126) stimulated leucocyte migration in a dose-dependent (30-300 microM) manner and, at the highest concentration used, this migration was comparable with that elicited by 2.5 nM interleukin 8 or 10 nM fMet-Leu-Phe peptide.

Actins↗
PubMed1996

In vivo wear of three types of metal on metal hip prostheses during two decades of use.

Wear was analyzed on 21 metal on metal hip replacements, including McKee-Farrar, Müller, and Ring, that were retrieved from patients after as many as 25 years. Light and scanning electron microscopy indicated that early wear included substantial third body abrasion, possibly from particles generated while scratches from the original polishing were being eradicated and from dislodged surface carbides. However, the main contact zones were eventually worn smoother than the original surfaces. Wear was quantified by digitizing the shapes of the components on a coordinate measuring machine and identifying those areas that deviated from the original spheric surface. On the femoral heads, wear was typically concentrated in the superomedial region, that is, on the load axis. Three cases also had substantial wear inferiorly, but there were no cases with circumferential (equatorial) wear. The long term wear rates averaged approximately 6 micrometers per year or less and produced an average of approximately 6 mm3 of metallic wear debris per year or less. Wear rate tended to increase as clearance increased over the range of 127 to 386 micrometers, and a McKee-Farrar prosthesis with the extreme clearance of 1.7 mm wore approximately 16 times faster than the average, but there was no apparent relationship between clearance and time to revision. Larger McKee-Farrar balls had less volumetric wear, on average, than smaller balls, and the Müller balls had the greatest wear, which may have been due to contact with the edges of recesses machined into the bearing zones of the Müller cups.

Biomechanical Phenomena↗
PubMed1996

Clusterin (SGP-2) induction in rat astroglial cells exposed to prion protein fragment 106-126.

Prion-related encephalopathies are characterized by the accumulation of an abnormal prion protein isoform (PrPSc) associated with neuronal degeneration and astrogliosis. The synthetic peptide homologous to PrP fragment 106-126 (PrP 106-126) induced in vitro neuronal apoptosis and glial proliferation. We used Northern blot analysis and the RNA polymerase chain reaction to assess the expression of several genes associated with programmed cell death and proliferation. Blots of total RNA extracted from neuronal and astroglial cells exposed to PrP 106-126 for between 1 h and 7 days were hybridized with probes recognizing c-fos, c-jun, c-myc, p53, hsp-70 and bcl-2 mRNA. Except for a slight decrease in bcl-2 mRNA in neuronal cells, no change in other transcripts was evident. Since clusterin (apolipoprotein J) mRNA levels are increased in prion-related encephalopathies and clusterin immunoreactivity has been located in association with PrPSc in Gerstmann-Sträussler-Scheinker brain, the expression of clusterin was determined in neuronal and astroglial cells chronically exposed to PrP 106-126. Although the induction of clusterin has been involved in the apoptotic mechanism in other experimental conditions, its expression was unchanged in PrP 106-126-treated neurons, while a three-fold induction of clusterin mRNA was observed in astrocytes exposed to PrP 106-126. To investigate whether the clusterin up-regulation was simply associated with the astroglial proliferative stimulus of PrP 106-126 or was specifically induced by the peptide, we measured clusterin expression in astrocytes cultured in fetal calf serum-free medium and exposed to PrP 106-126 or fetal calf serum restoration. In this condition the PrP peptide, like fetal calf serum, increased the glial proliferation rate, but only PrP 106-126 doubled clusterin mRNA. The selectivity of this effect indicates that PrPSc is directly involved in the clusterin up-regulation seen in prion-related encephalopathies and is associated with astroglial cells.

Animals↗
PubMed1996

Detection of prosthetic vascular graft infection using avidin/indium-111-biotin scintigraphy.

UNLABELLED: Prosthetic vascular graft infection, though rare, carries high morbidity and mortality rates; therefore, timely diagnosis is important. Patients, however, often present with vague symptoms, and radiological investigations are frequently inconclusive. These factors may lead to prolonged periods of observation and hospitalization, with the resultant increase in costs and complication rates, before reaching a final diagnosis. This prospective study evaluates the use of nonspecific avidin/111In-biotin imaging in diagnosing prosthetic vascular graft infection. METHODS: Twenty-five patients with a total of 29 grafts were investigated. Eighteen patients (19 grafts) had low probability of disease, whereas the remaining 7 patients (10 grafts) warranted surgical exploration based on clinical, laboratory or radiological evidence. Avidin was first injected intravenously and then followed 24 hr later by administration of 111In-biotin. Whole-body images were obtained 10 min and 2 hr postinjection of 111In-labeled biotin. SPECT imaging was performed 1 hr postinjection. Increased uptake along part or the whole length of the graft was considered evidence of graft infection. RESULTS: Avidin/111In-biotin scintigraphy correctly identified all infected grafts, as confirmed by culturing surgical specimens. In contrast, infection was correctly excluded in all but one of the grafts, and long-term follow-up was used to assess the presence of infection in patients who did not undergo surgical intervention. CONCLUSION: Avidin/111In-biotin scintigraphy is a simple and accurate imaging method for the routine diagnosis of vascular graft infection, and it may have a role in identifying the disease process in its initial stages, thus improving prognosis.

Aged↗
PubMed1995

Primary liver cancer in a high-incidence area in north Italy: etiological hypotheses arising from routinely collected data.

The incidence rate for primary liver cancer (PLC) was investigated in the Health Unit of Brescia (about 325,000 inhabitants), North Italy, in the 5-year period 1986-90, in order to ascertain whether there was a high risk for developing the disease in the area as suggested by mortality data. A total of 349 incident cases were observed (male: female ratio = 3.4: 1), of which 182 (52.1%) were diagnosed through histology. The cumulative risk was about 5% and 1% in males and females, respectively. The crude incidence rates were 34.5/100,000 in males and 9.4/100,000 in females, and the age-standardized rates were the highest among all those observed in the 9 Italian areas covered by Cancer Registries. Although about half of the cases in males can be attributed to either chronic alcoholic disease or HBV infection or both, further research is needed to investigate the role of known risk factors for PLC in the Health Unit.

Adult↗
PubMed1995

Patterns and covariates of alcohol drinking among high school students in 10 towns in Italy: a cross-sectional study.

A self-report questionnaire on alcohol and tobacco use was administered anonymously to 5221 high-school students in grade 9 (aged 14-15) and to 4154 students in grade 13 (aged 18-19) in 10 Italian towns. Alcohol consumption was greater among males than females and among 13th graders with respect to 9th graders. Students who drank alcoholic beverages every day were, in males and females, respectively, 22.5% and 9.0% among 9th grade and 31.3% and 10.0% among 13th grade students; those who drank 7 or more alcohol units a week were 26.8% and 11.1% among 9th grade and 42.7% and 13.9% among 13th grade students; finally, those who felt drunk at least once in the last 12 months were 19.8% and 13.9% among 9th grade and 41.4% and 19.0% among 13th grade students. Both alcohol consumption and frequency of drunkenness were found to be associated with both experimental and regular cigarette smoking and with psychoactive drug consumption, but not with socio-economic, cultural and demographic factors. Two main distinct drinking patterns were found among Italian adolescents: on the one hand, the daily drinking of moderate amount of wine with meals, together with parents, which was more common among males than females, as in other 'Latin' countries; and on the other hand, the occasional intake of alcoholic beverages in excess, especially beer and spirits, out of the family but together with peers.

Adolescent↗
PubMed1995

Incident cases of primary liver cancer (PLC): proposal for the use of a standardised method in case-definition.

We defined some standardised criteria for classifying incident cases of liver cancer into either Primary Liver Cancer (PLC) or Unspecified Liver Cancer (ULC), on the basis of the diagnostic procedures performed. A pilot hospital-based study (98 cases) was carried out in Verona, northern Italy, in order to assess the feasibility of the method. The same protocol was subsequently applied in a population-based study (349 cases) in Bresica, northern Italy. The percentage of cases with histological verification was 38.7 and 41.8%, respectively, with a wide variation among different hospitals. The percentage of cases we attributed to the PLC category was 78.6% in the hospital-based study and 78.8% in the population-based study. No differences in the proportion of cases attributed to PLC were found according to patients' age, sex or hospital of admission. Repeatability of the method was assessed through a cross-panel review of 198 cases, with a 91.9% interobserver agreement. Implications of this method are discussed and some suggestions for cancer registration and future research are proposed.

Aged↗
PubMed1995

Avidin and 111In-labelled biotin scan: a new radioisotopic method for localising vascular graft infection.

OBJECTIVES: To evaluate a new imaging technique, for diagnosis of prosthetic vascular graft infection. Avidin is a protein which accumulates nonspecifically at sites of inflammation or infection. Due to its extremely low dissociation constant with biotin sites of infection can be imaged, using avidin as a pre-target, followed by injection of 111In-labelled biotin. This technique is much simpler than the common scintigraphic methods which employ labelling of blood components and its target-to-background ratio is greater than the methods employing radiolabelled proteins. DESIGN: Prospective clinical study. SETTING: A single department of vascular surgery and one of nuclear medicine of a Northern Italian hospital. MATERIALS: Between May 1993 and May 1994, 31 grafts in 26 patients were studied; the series included 23 men and three women with a mean age of 65.5 years (range 54-76 years). The prosthetic graft (Dacron -16, ePTFE -15) were: aortoaortic 5, aortobifemoral 15, aortoiliac 1, and femoropopliteal 10. Sixteen patients were suspected of having a vascular graft infection (Group A), the other 10 patients served as controls (Group B). 20 mg of Avidin were injected iv, followed 24 h later by i.v. injection of 500 micrograms of Biotin labelled with 74 MBq of 111In. CHIEF OUTCOME MEASURES: Whole-body imaging was performed at 10 min and 2 h post-injection, along with SPECT imaging when indicated. Scan results were correlated with the traditional imaging modalities and the clinical outcome of the patients. MAIN RESULTS: In Group A: two patients (three grafts) were excluded from the study, there were six true-positives, one false-positive and 11 true-negatives. Results in Group B: 10 true-negatives. The overall sensitivity was 100%, the specificity 95%, the accuracy 96%, the positive predictive value 86% and the negative predictive value 100%. CONCLUSIONS: These data suggest that Avidin/111In-labelled Biotin scintigraphy is a useful non invasive diagnostic method for early diagnosis of suspected prosthetic vascular graft infection.

Aged↗
PubMed1995

Mural thrombi in abdominal aortic aneurysms: MR imaging characterization--useful before endovascular treatment?

PURPOSE: To evaluate magnetic resonance (MR) imaging accuracy in the characterization of mural thrombi in abdominal aortic aneurysms (AAAs). MATERIALS AND METHODS: Forty-five patients (37 men, eight women; mean age, 68 years) with an AAA with mural thrombus thicker than 1 cm at sonography underwent T1- and T2-weighted spin-echo MR imaging. The thrombi were prospectively classified as one of three signal intensity (SI) categories: category 1 corresponds to low SI on both T1- and T2-weighted images; category 2, high SI on T1-and T2-weighted images; and category 3, inhomogeneous SI with hyperintense areas on both T1- and T2-weighted images. During surgery, thrombi were classified as organized, unorganized, and partially organized. MR imaging and surgical findings were compared. RESULTS: SI category 1 corresponded to organized thrombi in 24 of 24 patients. Category 2 corresponded to unorganized thrombi in 11 of 11 patients. In category 3, focal hyperintense areas corresponded (both for presence and location) to unorganized portions of partially organized thrombi in 10 of 10 patients. CONCLUSION: MR imaging is accurate in AAA thrombus characterization.

Aged↗
PubMed1995

A new ePTFE stretch graft for aorto-iliac reconstructions. Surgical evaluation and one year follow-up with magnetic resonance imaging.

Since its introduction at the beginning of the 60s Dacron has proved to be a reliable and durable substitute for aortic reconstructions. It is however susceptible to late thrombosis, infection and aneurysmal dilatation in a significant number of cases. ePTFE vascular prosthesis, introduced in 1972, have proved to perform well for peripheral reconstructions and was used in aortoiliac position since 1980. In 1991 a new type of ePTFE rendered longitudinally extensible (Gore-Tex Stretch) was introduced into clinical practice. The aim of this study is to evaluate surgical performance, short term patency and interaction with periprosthetic tissues of Gore-Tex Stretch straight and bifurcated prosthesis. Between October 1991 and December 1993, 59 patients underwent aortic reconstruction at our Institution either for infrarenal aortic aneurysm (19 patients, 16 males, 3 females, mean age 68.8 +/- 8.5 years) or for aortoiliac occlusive disease (40 patients, 36 males, 4 females, mean age 60.5 +/- 7.2 years). Forty-eight bifurcated and eleven straight grafts were implanted using Gore-Tex sutures. Preoperative workup included Ultrasonography, Magnetic Resonance Imaging (MRI) in patients with aneurysms and Intra Arterial Digital Subtraction Arteriography (DSA) in patients with occlusive disease. Intraoperative parameters were recorded. Postoperative follow-up included ultrasonographic evaluation at 1st and 7th day, 15th postoperative week and at 3 monthly intervals; Intra Venous DSA before dismission and MRI at the 1st and 15th postoperative week. Intraoperatively the grafts proved to be soft and flexible with good handling and suturing characteristics. Perioperative bleeding was 480 +/- 299 ml for occlusive disease cases and 633 +/- 314 for aneurysm cases. No operative mortality was recorded.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

A neurotoxic prion protein fragment induces rat astroglial proliferation and hypertrophy.

Prion-related encephalopathies are characterized by the accumulation of an abnormal prion protein isoform (PrPSc) and the deposition of PrP amyloid in the brain. This process is accompanied by neuronal loss and astrogliosis. We recently showed that a synthetic peptide corresponding to residues 106-126 of human PrP is amyloidogenic and causes neuronal death by apoptosis in vitro. In the present study we investigated the effects of 1- and 14-day exposures of rat astroglial cultures to micromolar concentrations of this peptide as well as peptides homologous to other portions of PrP, a peptide corresponding to residues 25-35 of amyloid-beta protein, and a scrambled sequence of PrP 106-126. No significant changes were observed after 1-day exposure of cultures to any peptide. Conversely, 14-day treatment with PrP 106-126 (50 microM) resulted in a 5-fold increase in glial fibrillary acidic protein (GFAP) expression, as evaluated by Northern and Western blot analyses, and a 1.5-fold increment in cell number. Light and electron microscopy immunohistochemistry showed an enlargement in size and density of astroglial processes, and an increase in GFAP-immunoreactive intermediate filaments. These changes were not observed after 14-day treatment of cultures with the other peptides, including PrP 106-126 scrambled. The increase in GFAP expression of astroglial cultures exposed to PrP 106-126 was quantitatively similar to that found in scrapie-infected hamster brains.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

LDL oxidation in patients with severe carotid atherosclerosis. A study of in vitro and in vivo oxidation markers.

Among the various risk factors involved in the development and progression of carotid atherosclerosis, the oxidation of LDL has been proposed to play a relevant role. LDL oxidation has been investigated in 94 patients with severe carotid atherosclerosis undergoing elective carotid artery endarterectomy and in 42 matched control subjects. LDL oxidation was evaluated in all patients as (1) the susceptibility to in vitro oxidation, (2) vitamin E concentration and its efficiency in LDL, and (3) the presence of autoantibodies against oxidatively modified lipoprotein to monitor the occurrence of the oxidative processes taking place in vivo. No difference was detected between control subjects and patients concerning vitamin E concentration and the kinetics of conjugated diene formation in isolated LDL exposed to CuSO4. However, vitamin E efficiency was lower (9.6 +/- 4.2 versus 30.2 +/- 7.6 min/nmol vitamin E) and the duration of the vitamin E-independent lag phase was longer (105.5 +/- 16.5 versus 58 +/- 11.8 minutes) in the patient group. Autoantibodies against oxidatively modified lipoproteins were measured with an ELISA method using native LDL, Cu(2+)-oxidized LDL (oxLDL), or malondialdehyde-derivatized LDL (MDA-LDL) as antigens. To monitor cross-reactivity of the antibodies detected with other oxidatively modified proteins, human serum albumin (HSA) and MDA-derivatized HSA (MDA-HSA) were also employed. The antibody titer was calculated as the ratio of antibodies against modified versus native proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Smoking among high school students in 10 Italian towns: patterns and covariates.

The associations between tobacco smoking and demographic, socioeconomic, environmental, and behavioral factors among adolescents were investigated by administering an anonymous questionnaire to 5,221 ninth (aged 14-15 years) and 4,154 thirteenth grade (aged 18-19 years) students in 10 Italian towns. Using logistic regression analysis, both current smoking and experimental smoking were statistically associated with sibling, best friend, and partner smoking, alcohol drinking, and frequency of drunkenness in both grades and sexes. Attitude of parents toward children's smoking was also found to be associated with the probability of being a current smoker, especially among ninth graders. Parental smoking was associated with current smoking among females only. Socioeconomic factors and level of knowledge of the health consequences of smoking were not associated with either experimental or regular smoking. In conclusion, this survey suggests that social environment plays a fundamental role in both first experimentation with smoking and the process of becoming a regular smoker among adolescents. Students with one or more siblings who smoke, and especially those with best friends and a partner who smoke, were much more likely to have tried smoking and to be current smokers than students without smokers in their environment.

Adolescent↗
PubMed1994

[Magnetic resonance: preoperative assessment of abdominal aortic aneurysms. Comparison with surgical findings in 80 cases].

This work was aimed at assessing Magnetic Resonance (MR) accuracy in the preoperative investigation of abdominal aortic aneurysms, with a view to suggesting MRI as the method of choice for surgical planning, replacing other relatively invasive investigation techniques like angiography and enhanced CT. In the last 3 years 80 patients with abdominal aortic aneurysms identified with US or CT were examined with 0.5-T MRI and underwent surgical repair within 15 days. Spin-echo (SE) T1-weighted axial, sagittal and coronal sequences were always performed. In 18 patients gradient-echo (GE) flow sequences were also acquired; SE T2-weighted sequences were used to study parietal thrombi in 10 patients and finally Gd-DTPA T1-weighted sequences were obtained in inflammatory aneurysms (3 patients). MR images were blindly evaluated by 2 radiologists. The following variables which are useful for surgical planning were considered for each patient: aneurysm extent, characteristics of parietal thrombi, dissections, fixurations, inflammation signs, involvement of renal arteries, vena cava, ureters, duodenum, the presence of retroaortic renal vein or of other anomalies or associated conditions. MR images were always compared with intraoperative findings, since surgery was considered as the gold standard. MR findings were in agreement with surgical findings in the evaluation of cranio-caudal aneurysm extent (78/80), parietal thrombus features (80/80), dissection (1/1) and fixuration signs (8/9), origin of renal arteries (80/80), inferior vena cava involvement (3/3), other anatomical anomalies or conditions (6/6). Inflammation signs were overestimated (14/8) as well as adhesion between aneurysm and duodenum (17/13). The presence of distal renal polar arteries was underestimated (2/4). In conclusion, MRI proves to be a highly sensitive method to demonstrate abdominal aortic aneurysms and is therefore suggested as the examination of choice before surgery.

Adult↗
PubMed1993

[The surgical treatment of inflammatory aneurysms of the abdominal aorta. The usefulness of nuclear magnetic resonance (MR) in the preoperative diagnosis].

Inflammatory abdominal aortic aneurysms (IAAA) represent a peculiar variant compared with the common atherosclerotic origin of aortic aneurysms. Between January 1988 and March 1992, 111 aneurysmectomies were performed at our institution: 98 elective and 13 emergency procedures. In 10 cases (all males, mean age 68.5) an IAAA was found. 8/10 of those patients operated upon electively were studied preoperatively with MRI. All the IAAA but one were correctly identified preoperatively. Identification of IAAA with MRI in these cases improved the surgical approach. In conclusion, patients with IAAA can be operated upon safely especially if a preoperative diagnosis is present. MRI greatly improves our ability to characterize non invasively IAAA.

Aged↗