Biomedical subjects

R Chiesa

Publications and source records attributed to R Chiesa.

At least 55 records · Page 3Linked to original sources

PubMed2000

Computer-assisted EEG monitoring during carotid endarterectomy.

The purpose of this study was to develop a reliable method of EEG analysis during carotid endarterectomy. EEGs of 104 patients under general anesthesia were processed by three different methods: a) "on-line" visual analysis during surgery, b) "off-line" visual analysis in laboratory, and c) computer analysis. To identify pathological EEGs, variability and asymmetry indexes of the 0.5-3.5 Hz and 8-15 Hz bands, absolute power and variability indexes of spectral edge frequency (SEF), and main dominant frequency were evaluated. On-line visual analysis showed clamp-related modifications in 29 EEGs (27.9%). Off-line visual analysis detected 24 pathological EEGs (23.1%): 18 with major changes and 6 with moderate changes. Computer analysis showed 21 EEGs (20.19%) with at least one altered index and 7 (6.7%) with altered variability for both SEF and 8-15 Hz power. The statistical analysis was significant for SEF variability and for 8-15 Hz power variability and asymmetry (P < 0.0001, analysis of variance test). While SEF and 8-15 Hz power variability did not appear influenced by anesthesia and single electrode artifacts, 8-15 Hz power asymmetry index was confounded by the presence of contralateral internal carotid occlusion. The data show that the use of these spectral indexes adds objective information to visual analysis, supporting and making easier intraoperative strategies. Their routine clinical use does not involve additional costs remaining technical requirements unchanged compared to traditional recording.

Aged↗

PubMed2000

Mortality from cancer and chronic respiratory diseases among workers who manufacture carbon electrodes.

OBJECTIVES: To investigate the risk of cancer and non-neoplastic respiratory diseases among workers who manufacture carbon electrodes, as this industry entails exposure to mixtures of polycyclic aromatic hydrocarbons. METHODS: A historical cohort study was carried out of 1006 male workers employed for at least 1 year between 1945 and 1971 in a carbon (graphite) electrode production plant in central Italy, who were followed up for mortality between 1955 and 1996. The ratio of observed to expected deaths (standardised mortality ratios, SMRs) was computed from both national and (for the period 1964-96) regional age and period specific mortalities. A multivariate Poisson regression analysis was performed to investigate the relative risk (RR) of death according to duration of employment and time since first employment in the factory. RESULTS: A total of 424 workers had died, 538 were still alive, and 44 were lost to follow up. Mortalities from all causes, all cancers, and respiratory tract cancer were in line with the regional figure. An excess was found over the expected deaths from skin cancer including melanoma (SMR 3.16, 95% confidence interval (95% CI) 0.65 to 9.23) and from non-neoplastic respiratory diseases (SMR 1.58, 95% CI 1.16 to 2.11). Poisson regression analysis including age as a covariate showed an increased risk of dying from gastric cancer with increasing duration of employment, and an increase in the RR of dying from lung cancer and from non-neoplastic respiratory diseases with increasing time since first employment, although the linear trend was not significant. CONCLUSION: This study supports previous findings that working in the carbon electrode manufacturing industry may not increase the risk of dying from respiratory cancer. However, a possible association with non-malignant respiratory diseases cannot be excluded.

Adult↗

PubMed2000

Stent-graft treatment of a common carotid artery pseudoaneurysm.

PURPOSE: To report a case demonstrating successful endovascular treatment of a right common carotid artery pseudoaneurysm using a commercially prepared balloon-expandable covered stent. METHODS AND RESULTS: A 50-year-old man was evaluated for syncopal episodes. He had a history of severe trauma sustained in a motor vehicle accident 3 years before symptom onset. Doppler ultrasound scanning detected a pseudoaneurysm at the origin of the right common carotid artery. The defect measured 25 mm x 20 mm with a 22-mm-long neck on angiography and computed tomography; there was no evidence of carotid stenosis or associated vascular pathology. Via a percutaneous femoral access, 2 Jostent peripheral stent-grafts were placed at the level of the aneurysm, safely achieving complete repair of the arterial wall defect. The patient was asymptomatic at his 12-month evaluation. Color flow duplex scans showed continued exclusion of the pseudoaneurysm. CONCLUSIONS: Wide-necked aneurysms in the extracranial carotid arteries may be treated with stent-grafts, which can achieve complete and permanent reconstruction of the arterial wall by excluding the aneurysm.

Aneurysm, False↗

PubMed2000

Etiology of hepatocellular carcinoma in Italian patients with and without cirrhosis.

We performed a case-control study to assess the role of hepatitis B virus (HBV), hepatitis C virus (HCV), GB virus C/hepatitis G virus (HGV), TT virus, alcohol intake, and tobacco smoking as risk factors for hepatocellular carcinoma (HCC) in the presence or absence of cirrhosis. We prospectively recruited 174 patients with a first diagnosis of HCC admitted to the main hospitals in Brescia, North Italy. On the basis of histological, clinical, and radiological criteria, the presence of cirrhosis was established in 142 cases, excluded in 21 cases, and remained undefined in 11 cases. Among the HCC cases without cirrhosis, a histological picture of normal liver was found in a single patient, chronic viral hepatitis was found in 11 patients, alcoholic hepatitis was found in 5 patients, nonspecific reactive hepatitis was found in 3 patients, and hemochromatosis was found in 1 patient. As controls, we also included 610 subjects unaffected by hepatic diseases and admitted to the same hospitals as cases. The odds ratios for having HCC according to positivity for HCV RNA, HBsAg and/or HBV DNA, and alcohol intake > 80 g/day (95% confidence interval) were as follows, in the presence and absence of cirrhosis, respectively: (a) 33.5 (17.7-63.4) and 19.7 (6-64.8) for HCV RNA; (b) 17.6 (9.0-34.4) and 20.3 (5.7-72.6) for HBsAg; and (c) 5.5 (3.1-9.7) and 4.6 (1.5-13.8) for alcohol intake. No association was found with HGV or TT virus infections or tobacco. This study has shown that most HCC cases arising in the area are due to HBV, HCV, or alcohol intake, in both the presence and absence of cirrhosis.

Aged↗

PubMed2000

Evidence based assessment of long-term results of plaque incision and vein grafting for Peyronie's disease.

PURPOSE: We assessed the long-term outcome of plaque incision and vein grafting in select patients with Peyronie's disease by extensive preoperative and postoperative subjective and objective analysis. MATERIALS AND METHODS: From January 1995 to June 1998, 50 men 28 to 62 years old (mean age 44) underwent surgery. Patients were evaluated preoperatively, 3 months after surgery and at a mean long-term followup of 32 months by sexual history, physical examination, determination of penile length and degree of curvature, dynamic color power Doppler sonography of the penile vessels and nocturnal RigiScan* evaluation for 3 nights. Study inclusion criteria were penile curvature 45 degrees or greater that made vaginal intromission impossible, stable disease for at least 6 months, patient reported normal penile rigidity, normal penile hemodynamics on color power Doppler ultrasound, normal nocturnal penile rigidity with at least 1 erection nightly (including base and tip rigidity greater than 60%, and a duration of 10 minutes) and absent base-tip discrepancies. Plaque was usually approached via a combined subcoronal and midline sagittal scrotal incision. Maximal rigidity was created intraoperatively and 1 to 3 plaque incisions were made. Saphenous vein patches were then grafted at the incision sites. Postoperatively patients were systemically treated with neurotrophic factors and low molecular weight heparin. Local vacuum supported corporeal stretching was done and weekly alprostadil injections were given to optimize corporeal oxygenation. RESULTS: At long-term followup complete penile straightening was achieved in 40 cases (80%), minor residual curvature of 30 degrees or less persisted in 7 (14%) and significant disease recurred in 3 (6%). Penile rigidity was equal to that preoperatively in 47 patients (94%), while 3 (6%) reported clinically significant decreased potency. Penile length was equal to that preoperatively in 30 patients (60%), while 20 (40%) noticed slight penile shortening. Postoperatively penile color power Doppler sonography showed vascular impairment in 5 men (10%) and nocturnal RigiScan testing revealed a significant decrease in nightly erections in 5 (10%). Surgical complications included penile hypoesthesia in 1 case (2%), penile hematoma in 2 (4%), wound infection in 1 (2%) and glandular ischemia in 1 (2%). CONCLUSIONS: Plaque incision and vein grafting achieved satisfactory clinical results in the majority of patients with severe and stable Peyronie's disease, intact penile rigidity preoperatively, normal penile color power Doppler ultrasound and normal nocturnal RigiScan testing.

Adult↗

PubMed2000

Endovascular treatment of a noninfected anastomotic juxtarenal aortic aneurysm.

An 82-year-old man underwent an endovascular procedure with a commercially available endovascular graft for an anastomotic juxtarenal abdominal aortic aneurysm. The anastomotic aneurysm, which showed no sign of infection, developed 4 years after implantation of an aortic end-to-end graft for an infrarenal aortic aneurysm. The aneurysm was diagnosed during routine ultrasonographic follow-up; there was no apparent infection of the graft. Aortography confirmed the diagnosis and also revealed a small pseudoaneurysm at the level of the distal aortic anastomosis. Endovascular surgery was performed in the operating room with the guidance of C-arm fluoroscopy and intravascular ultrasound. Two Vanguard Straight Endovascular Aortic Graft Cuffs (26 x 50 mm and 24 x 50 mm) were implanted, successfully excluding both the anastomotic juxtarenal aortic aneurysm and the distal pseudoaneurysm. The renal arteries were preserved and no early or late endoleaks were observed. The patient was discharged 2 days after the procedure. Sixteen months later, he was alive and well, with no endovascular leakage, no enlargement of the aortic aneurysms, and no sign of infection. In our opinion, this experience shows that commercially available endovascular grafts may be used successfully to treat anastomotic aortic aneurysms and pseudoaneurysms.

Aged↗

PubMed1999

Case-control study on hepatitis C virus (HCV) as a risk factor for hepatocellular carcinoma: the role of HCV genotypes and the synergism with hepatitis B virus and alcohol. Brescia HCC Study.

We performed a case-control study to evaluate the risk of hepatocellular carcinoma (HCC) for hepatitis C virus (HCV) infection. A total of 305 newly diagnosed HCC cases (80% males) and 610 subjects (81% males) unaffected by clinically evident hepatic disease admitted to the 2 main hospitals in Brescia, North Italy, were recruited as cases and controls, respectively. Among the 122 HCC cases positive for HCV RNA, genotype 1b was found in 83 patients (68%), genotype 2 in 36 (29.5%) and genotype 1a in 3 (2.5%). Among the controls, 15 were infected with genotype 1b and 15 with type 2. Analysis of HCV envelope 1 nucleotide sequence among 25 cases and 8 controls infected with genotype 2 showed subtype 2c in 96% of cases and in all controls, and subtype 2a in 1 HCC case. The odds ratio (OR) for HCV RNA positivity adjusted for hepatitis B virus (HBV) markers and alcohol intake was 26.3 [95% confidence interval (CI): 15.8-44], and it was higher for genotype 1b (OR = 34.2) than type 2 (OR = 14.4). The OR for HCV RNA was 35.6 (95% CI: 14.5-87.1) when the HBV markers were all negative and 132 (15.3-890) when HBsAg positivity was present; the OR was 26.1 (95% CI: 12.6-54.0) among subjects with alcohol intake of 0-40 g/day and increased to 62.6 (23.3-168) and 126 (42.8-373) with an alcohol intake of 41-80 and >80 g/day, respectively. In conclusion, synergism was found between HCV infection and HBV infection and alcohol intake in causing HCC.

Adult↗

PubMed1999

A case-control study on a novel DNA virus (TT virus) infection and hepatocellular carcinoma. The Brescia HCC Study.

We performed a case-control study to evaluate the association of a new human DNA virus named TT virus (TTV) with hepatocellular carcinoma (HCC). We recruited 174 subjects hospitalized for HCC (84% males; mean age: 64 years) and 118 patients hospitalized for non-liver diseases in Brescia, northern Italy, as controls (94% males; mean age: 66 years). TTV DNA was found in serum by polymerase chain reaction (PCR) in 26 cases (15%) and 11 controls (9.3%) (P >. 1). TTV group 2 infection was identified in 16 cases (61.5%) and 4 controls (36.4%) (P >.1) using a type-specific PCR method. Sequence analysis of 222 nt of TTV DNA demonstrated that the remaining 10 cases and 7 controls were all infected by group 1. The odds ratio (OR) for TTV-DNA positivity, adjusted for demographic variables, hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) RNA, and heavy alcohol intake was 1.8 (95% CI: 0.7-4.8; P >.1). The OR did not change when the analysis was restricted to 14 HCC cases and 56 controls who were negative for each known risk factor for HCC (OR = 1.7; 95% CI: 0.8-4.0). TTV-DNA positivity was not associated with transfusion history. The prevalence of TTV DNA was higher among HCC cases positive for HBsAg (10 of 38 [26.3%]) than among those positive for HCV RNA (8 of 62 [12.9%]) or negative for hepatitis B virus (HBV), HCV, and hepatitis G virus (HGV) infections (5 of 62 [8. 1%]) (P =.02). This study does not support the hypothesis of an association between TTV infection and HCC.

Adult↗

PubMed1999

Demonstration of viable Chlamydia pneumoniae in atherosclerotic plaques of carotid arteries by reverse transcriptase polymerase chain reaction.

The presence of Chlamydia pneumoniae in atheromas has been demonstrated in several studies. Culture of the organism from arterial tissue has been difficult. We report the use of a reverse transcriptase polymerase chain reaction to detect viable Chlamydia pneumoniae in carotid atheromas. We analyzed 30 patients (14 females, mean age 69.6 +/- 8.8 years) who underwent surgery for the removal of atherosclerotic plaques from carotid arteries. During surgery, samples of lingual vein and superior thyroideal artery were also taken. We applied two molecular biology techniques to the carotid plaques on lingual vein or thyroideal artery samples: 1) polymerase chain reaction (PCR) and 2) reverse transcriptase-PCR (RT-PCR) for the detection of bacterial mRNA, employing PCR primers designed to detect a fragment of the 16S rRNA gene. Blood samples were obtained from the patients for determination of Chlamydia pneumoniae IgG, IgA, and IgM antibody titers by a microimmunofluorescence technique. The results of the present study confirmed the presence of viable Chlamydia pneumoniae in atheromas and support the hypothesis that the organism may be an active factor in the pathogenesis of atherosclerosis.

Aged↗

PubMed1999

In vitro and in vivo behaviour of Ca- and P-enriched anodized titanium.

The influence of different surface preparations on titanium biocompatibility and bone integration was evaluated. Commercially grade 2 titanium rods (diameter 2 mm, length: 3 mm), vacuum annealed and hydrofluoric acid etched was selected for its promising surface characteristics to achieve good direct osseointegration. Some rods were surface modified by Anodic Spark Discharge anodization and a thin layer (approximately 5 microm) of amorphous TiO2 containing Ca and P (Ti/AM) was obtained. Some of the Ti/AM specimens underwent a further hydrothermal treatment to produce a thin outermost layer (approximately 1 microm) of hydroxyapatite (Ti/AM/HA). Cytotoxicity tests (direct contact: ISO 10993-5) showed good cytocompatibility for all tested samples. Ti and tissue culture substrate + DMEM control, respectively, were associated with a significant higher proportion of attached cells than Ti/AM and Ti/AM/HA (P < 0.0005), but this was in the normal range of 10-20% of unattached cells for cytocompatible materials. Histomorphometric analysis conducted on samples inserted in the cancellous bone of distal femoral epiphysis of Sprague-Dawley rats gave the following results at 4 and 8 weeks: Affinity index (AI%) data proving the surface osteconductive properties of non-anodized acid etched Ti (AI-4 weeks: 67.1 +/- 17.0%; AI-8 weeks: 74.8 +/- 11.5%). Ti/AM samples showed the lowest values (AI-4 weeks: 45.8 +/- 15.9%; AI-8 weeks: 68.5 +/- 13.6%) while the best performances of the Ti/AM/HA samples (AI-4 weeks: 60.4 +/- 21.8%; AI-8 weeks: 79.5 + 9.37%) indicated that hydroxyapatite allowed a higher bone to implant contact respect to Ti only. Further investigations should be performed in order to better understand the mechanism of observed in vitro behaviour and to achieve information on long-term osseointegration process.

Analysis of Variance↗

PubMed1999

Intraoperative stenting of the internal carotid artery after unsuccessful eversion endarterectomy.

Stenting of the internal carotid artery (ICA) has been shown to be feasible in atherosclerotic lesions, in restenosis after carotid endarterectomy, and in spontaneous carotid dissections. To correct an intimal flap that detached distal occlusion of the ICA after eversion carotid endarterectomy, as shown with intraoperative completion angiography, we successfully used stenting of the ica with a self-expandable stainless steel stent placed during surgery through the common carotid artery.

Carotid Artery, Internal↗

PubMed1999

A case-control study on family history of liver cancer as a risk factor for hepatocellular carcinoma in North Italy. Brescia HCC Study.

OBJECTIVES: We carried out a case-control study to investigate the role of history of liver cancer in a first-degree relative as a risk factor for hepatocellular carcinoma (HCC). METHODS: Two hundred eighty-seven HCC incident cases and 450 subjects unaffected by liver disease (controls) were enrolled in the study. Family history of liver cancer and other malignancies and history of alcohol intake were collected by face-to-face interview. Blood samples were analyzed for HBsAg, anti-HCV and HCV RNA positivity. RESULTS: Family history of liver cancer was associated with HCC (odds ratio [OR] = 2.4; 95% confidence interval [CI] = 1.2-4.7), whereas family history of other malignancies was not (OR = 1.0; 95% CI = 0.61.5). An increased OR for family history of liver cancer was found among subjects negative for the other risk factors (OR = 2.0; 95% CI = 0.6-6.9). A synergism of family history of liver cancer was also evident with hepatitis B and hepatitis C virus infection and with heavy alcohol intake. CONCLUSIONS: This study suggests a role of family history independent from and interacting with known risk factors for hepatocellular carcinoma.

Adult↗

PubMed1999

Chlamydia pneumoniae eradication from carotid plaques. Results of an open, randomised treatment study.

OBJECTIVE: to determine the effect of specific antibiotic treatment with roxithromycin in the eradication of Chlamydia pneumoniae from carotid artery plaques. DESIGN: prospective open randomised treatment study. PATIENTS AND METHODS: we analysed 32 patients (16 females, mean age 70.1+/-14.7 years) who underwent surgery for the removal of atherosclerotic plaques from carotid arteries. During surgery samples of lingual vein and superior thyroid artery were also taken. Before surgery, patients were randomised to receive either roxithromycin 150 mg twice daily or no treatment. Sixteen patients were treated with antibiotic for a mean of 26 days (range 17-35 days). The two groups of patients were comparable in terms of age, sex, risk factors, and seroprevalence for C. pneumoniae. We applied a semi-nested polymerase chain reaction (PCR) technique to the carotid plaques, lingual vein, and thyroid artery samples. Blood samples were obtained from the patients for the determination of C. pneumoniae IgG, IgA, and IgM antibody titres by a microimmunofluorescence technique. RESULTS: in twelve out of sixteen non-treated patients we found evidence of C. pneumoniae DNA in the carotid plaques. Conversely, C. pneumoniae DNA was detected in only five out of sixteen treated patients (p=0.034, Chi-squared test). In all cases PCR was negative for the lingual vein and thyroid artery samples. CONCLUSIONS: Roxithromycin seems effective in reducing the bacterial burden of C. pneumoniae within atherosclerotic plaques, although extended follow-up is needed to determine whether antibiotic treatment benefits long-term patient outcome.

Aged↗

PubMed1999

Chlamydia pneumoniae DNA detection in peripheral blood mononuclear cells is predictive of vascular infection.

Abdominal aortic aneurysm tissue and peripheral blood mononuclear cells (PBMC) of 41 consecutive subjects undergoing abdominal aortic aneurysm surgery were analyzed by polymerase chain reaction (PCR) for the presence of Chlamydia pneumoniae, Mycoplasma pneumoniae, and Helicobacter pylori DNA. Twenty patients (49%) were positive for C. pneumoniae DNA-16 (39%) in both PBMC and aneurysm tissue, 3 (7.3%) in PBMC only, and 1 (2.4%) in the artery specimen only. Previous exposure to C. pneumoniae was confirmed in 19 (95%) of the 20 PCR positive subjects by C. pneumoniae-specific serology, using the microimmunofluorescence test. None was positive for H. pylori or M. pneumoniae DNA, either in the PBMC or in the artery specimens. In conclusion, carriage of C. pneumoniae DNA is common both in PBMC and in abdominal aortic tissue from patients undergoing abdominal aneurysm surgery. Blood PCR may be a useful tool for identifying subjects carrying C. pneumoniae in the vascular wall.

Aged↗

PubMed1999

Prevalence of GB virus-C/hepatitis G virus infection in patients with cryptogenic chronic liver disease and in patients with primary biliary cirrhosis or Wilson's disease.

OBJECTIVE: To assess the role of hepatitis G virus (HGV) in cryptogenic chronic liver disease (CLD), we investigated the prevalence of HGV RNA among patients with cryptogenic CLD, patients with nonviral CLD (primary biliary cirrhosis [PBC] and Wilson's disease [WD]) and subjects without clinically evident liver disease (controls). METHODS: Ninety patients with cryptogenic CLD (43 with chronic hepatitis, 20 with cirrhosis, and 27 with hepatocellular carcinoma [HCC]), 143 patients with PBC, 22 patients with WD, and 134 controls were recruited. HGV RNA was detected by reverse transcription-polymerase chain reaction (RT-PCR) and antibodies against HGV E2 protein (anti-E2) by an immunoassay test. RESULTS: HGV RNA was detected in 7.8% of patients with cryptogenic CLD (chronic hepatitis, 9.3%; cirrhosis, 5.0%; HCC, 7.4%), in 2.4% of patients with PBC or WD, and in 2.2% of controls. As a consequence, a positive association of HGV infection with cryptogenic CLD was found (odds ratio, 3.1; 95% confidence interval [CI], 1.0-9.7; p = 0.05). No difference was observed between HGV RNA-positive and -negative patients by age, sex, histology, or liver function tests. Anti-E2 prevalence did not differ between patients with cryptogenic CLD (26.5%), patients with PBC (28.1%), and controls (22.1%). Transfusion history was associated with HGV RNA but not with anti-E2 seropositivity. CONCLUSIONS: Although an association was found between cryptogenic CLD and HGV infection, the role of the virus seems far from important, the proportion of cryptogenic CLD attributable to it being only 5.2%.

Antibodies, Viral↗

PubMed1999

Endovascular treatment of aortic aneurysms of the abdominal aorta with covered stents.

Abdominal aortic aneurysms are common in the aging population; their surgical treatment is well established and allows good results in specialized centers. Endovascular exclusion of abdominal aortic aneurysms has been shown to be feasible since 1991 and nowadays commercially available bifurcated endografts allow safe exclusion in selected cases. In the last year 22 patients with an aorto-iliac aneurysm received endovascular treatment at our Institution. We included patients with favorable anatomic characteristics (i.e. neck > 15 mm length, and < 28 mm diameter, iliac neck < 12 mm diameter, absence of > 90 degrees iliac or aortic angulation) and, in particular, those with increased surgical risk for systemic pathology (12 patients), or hostile abdomen (9 patients). We employed Vanguard II (Boston Scientific) endovascular grafts introduced through a surgically exposed common femoral artery; the contralateral limb of bifurcated grafts was inserted percutaneously. The endograft was successfully implanted in all cases, requiring additional iliac cuffs for complete aneurysm exclusion in 3 cases. Periprocedural morbidity included one case of thrombosis and one case of pseudoaneurysm of the punctured femoral artery, which required surgical treatment. In one case surgical exposure of the iliac artery was required in order to advance the device into the aorta. In one patient who previously underwent hemicolectomy, postoperative colonic ischemia was observed, and pharmacological treatment was required. Moreover we also observed one case of groin infection that was treated successfully with local wound care and systemic antibiotics, and one late contralateral limb thrombosis that was successfully treated with loco-regional thrombolysis. The mean follow-up was 6.1 months: one patient died because of congestive heart failure. No further morbidity was recorded. A type-II endoleak was observed in one patient, originating from the inferior mesenteric artery with no sac enlargement; this patient is still under observation. In conclusion, with proper clinical selection, commercially available endovascular devices allow safe exclusion of abdominal aortic aneurysms. Long-term follow-up is needed to ascertain the durability of the procedure.

Aorta, Abdominal↗

PubMed1998

The relevance of hydroxyapatite and spongious titanium coatings in fixation of cementless stems. An experimental comparative study in rat femur employing histological and microangiographic techniques.

Pure titanium rods plasma-spray coated with hydroxyapatite (HA) or porous titanium (Ti) of controlled roughness were implanted bilaterally in the distal femur of Sprague-Dawley rats to compare the extent of bone growth on the two types of coating. The relevance of other factors, like mechanical stability and biological adaptation of the bone to the insertion of a foreign body implant, were investigated in femora which were over-reamed (absence of primary fit) or reamed without insertion of the rod. Continuous tetracycline labeling for the first 30 days and for the last 2 weeks in the 90-day group was performed; histological/histometric, fluorescence and microangiographic studies were carried out on serial sections of the implanted and control femora. In the group of stable implants, HA-coated rods showed 90% integration versus 53% with Ti-coated implants (P < 0.001); in over-reamed implants neither surface bone growth nor endosteal fixation occurred, and both types of rods were surrounded by a thick layer of connective tissue. The study documented early adhesion of osteoblasts and direct deposition of bone matrix on the substrate, while on spongious titanium osteogenesis was observed only in proximity to the surface. Remodeling of the reactive, primary bone to mature, lamellar bone took the form of a capsule surrounding the implants and radial bridges connecting the latter to the endosteal surface. The number, height and thickness of these bridges appeared to be the factors determining implant stability, rather than the extent of the bony capsule on the perimeter of the implant. Integration was a function not only of mechanical conditions and surface geometry, but also of the biological response of the whole bone to changes in the vascularization pattern. The reported phenomena can be seen more easily in experimental models involving small rodents because of their fast bone turnover and revascularization, but it is expected that they take place, even at a lower speed, in clinical situations like cementless stems of total hip replacement.

Angiography↗

PubMed1998

In search of biological markers of high-risk carotid artery atherosclerotic plaque: enhanced LDL oxidation.

The oxidation of low density lipoprotein (LDL) is a key event in the development and progression of atherosclerosis because it generates molecular epitopes that are more atherogenic than parent LDL. We found previously that patients with carotid atherosclerosis have a significantly higher titer of autoantibodies against oxidatively modified LDL than normal subjects. The aim of this study is to correlate biological markers of in vivo LDL oxidation with the degree of carotid stenosis and of plaque ulceration (PU) in a series of patients undergoing carotid endoarteriectomy (CEA). Ninety-four consecutive patients (68M and 26F, aged 67.3 +/- 8.2 years) who underwent CEA at our institution between June 1993 and January 1994 were included in the study. The degree of carotid stenosis and the presence and extent of PU were correlated with the level of autoantibodies (IgG) against oxidatively modified LDL (Cu++-oxidized [oxLDL] or malondialdehyde derivatized LDL [MDA-LDL]), that consistently mirrors the occurrence of oxidative modifications in vivo. A statistically significant correlation (r = 0.23, p = 0.039) was found between the degree of carotid stenosis and antiMDA-LDL specific ratio (a parameter that describes the specificity of LDL towards other proteins as target for oxidative modification). A statistically significant correlation was also found between the PU score and antioxLDL IgG (r = 0.32, p = 0.011), antiMDA-LDL IgG (r = 0.25, p = 0.045) and antiMDA-LDL IgG specific ratio (r = 0.38, p = 0.002). None of the classical biochemical parameters (total, LDL and HDL cholesterol and triglycerides) correlated with the above-mentioned plaque characteristics. The results shown, support the use of biological markers of in vivo LDL oxidation (antioxidatively modified LDL autoantibody titers) to evaluate the clinical setting of high-risk carotid atherosclerosis both in screening and in follow-up studies.

Aged↗