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Biomedical subjects

A Colombo

Publications and source records attributed to A Colombo.

At least 181 records · Page 10Linked to original sources
PubMed1998

Identification of a multixenobiotic resistance mechanism in Xenopus laevis embryos.

In the '90's a membrane-associated transport protein, discovered in aquatic organisms, was considered to be expressed in response to environmental xenobiotics. Like the multidrug resistance protein found in mammalian tumor cell lines, this protein confers resistance in organisms in polluted areas by binding xenobiotics and transporting them out of the cells in an energy-dependent manner. This study investigates the expression and the activity of a P-glycoprotein (Pgp) involved in a multixenobiotic resistance mechanism (MXRM) during the early developmental stages and in tissues of adult Xenopus laevis.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Bioindicators for toxicity assessment of effluents from a wastewater treatment plant.

The discharge of effluents and toxic compounds into aquatic systems represents a growing environmental problem involving an impact on water ecology and potential effect on human health. Most municipal wastewaters are complex mixtures; their complexity led as to carry out a hazard assessment using chemical analyses and biological tests. This study investigates biochemical alteratiobns in two sentinel organisms, the Anodonta cygnea mussel and the Xenopus laevis frog exposed for different lengths of time to various concentration of wastewater of the S. Antonino Ticino treatment plant. The results point out the long-life of toxic compounds.

Animals↗
PubMed1998

Coronary artery stenting in the elderly: short-term outcome and long-term angiographic and clinical follow-up.

OBJECTIVES: This study sought to compare the short- and long-term outcomes of elderly patients undergoing coronary artery stenting with those of younger patients and to determine the long-term clinical outcome and survival of elderly patients post stent implantation. BACKGROUND: Elderly patients undergoing coronary revascularization are considered a high-risk group. Few data exist that relate the results of stenting in treating coronary artery disease in the elderly population. METHODS: All elderly patients >75 years of age who underwent coronary artery stenting between March 1993 and July 1997 (n=137) at our center were compared to the patients <75 who underwent coronary artery stenting during the same time period (n=2,551). Long-term clinical follow-up and survival were determined for the elderly group. RESULTS: Elderly patients presented with lower ejection fractions (54% vs. 58%, p=0.0001), more unstable angina (47% vs. 28%, p=0.0001), and more multivessel disease (78% vs. 62%, p= 0.0001) than younger patients. These older patients had higher rates of procedure related complications including procedural myocardial infarction (MI) (2.9% vs. 1.7%, p=0.2), emergency CABG (3.7% vs. 1.4%, p=0.04), and death (2.2% vs. 0.12%, p=0.0001). Angiographic follow-up, obtained in both groups, demonstrated significantly higher restenosis rates in the elderly versus younger patients (47% vs. 28%, p=0.0007). Longer term clinical follow-up, which was obtained only in the elderly group, showed that at a mean follow-up period of 12 months post coronary stenting, elderly survival free from death, MI, revascularization and angina was 54% and that their overall survival was 91%. Subanalysis of the elderly patients who died showed much higher incidence of combined unstable angina (80%), prior MI (60%), lower ejection fraction (46%), multivessel disease (100%) and complex lesions (100%) than the overall group. CONCLUSIONS: Elderly patients who undergo coronary artery stenting have significantly higher rates of procedural complications and worse six month outcomes than younger patients, especially those who present with combined unstable angina, history of MI, EF < 50%, multivessel disease and complex lesions. Overall survival in the elderly population at 12 months postcoronary artery stenting was 91% and event-free survival was 54%.

Aged↗
PubMed1998

Fournier's gangrene: a clinical presentation of necrotizing fasciitis after bone marrow transplantation.

Three patients with ANLL developed Fournier's gangrene as an early complication after allo-BMT (two cases) and auto-BMT (one case); two patients were in first CR, the third had resistant disease. Patients developed fever, perineal pain, swelling and blistering of the genital area. Pseudomonas aeruginosa was isolated from the lesions and patients received systemic antibiotic therapy, surgical debridement and medication with potassium permanganate solution. Two patients made a complete recovery although one died of sepsis. The third had progressive involvement of the abdominal wall and later died of leukemia. Early diagnosis of this disorder and prompt initiation of appropriate therapy can prevent progression of this acute necrotizing infection.

Abdominal Muscles↗
PubMed1998

Intravascular ultrasound-guided optimized stent deployment. Immediate and 6 months clinical and angiographic results from the Multicenter Ultrasound Stenting in Coronaries Study (MUSIC Study)

OBJECTIVES: A study was set up to validate the safety and feasibility of intravascular ultrasound-guided stenting without subsequent anticoagulation, and its impact on the 6 months restenosis rate. METHODS: The study was designed to be multicentred, prospective, and observational. RESULTS: One hundred and sixty-one patients with stable angina and a de novo coronary artery lesion were enrolled. In four patients, the implantation of a Palmaz-Schatz (with spiral bridge) stent had failed. One of these four patients died 3 days following bypass surgery. In two other patients, intravascular ultrasound assessment was not performed. One hundred and twenty-five of the remaining 155 patients (81%) were treated with aspirin (100 mg x day(-1)), because all three criteria for optimized stent expansion were met. Twenty-two of the remaining 38 patients (25%), in whom at least one criterion was not met were treated with aspirin and acenocoumarol (3 months, INR 2.5-3.5), while 16 patients only received aspirin. Stent thrombosis was documented in two patients (1.3%) for which repeat angioplasty was performed. During the hospital stay, there were no deaths or Q-wave myocardial infarctions. Five patients (3.2%) sustained a non-Q-wave myocardial infarction. During the follow-up period (198+/-38 days, complete for all patients, except one), one patient (0.6%) sustained a Q-wave myocardial infarction, one (0.6%) underwent bypass surgery, and repeat angioplasty was performed in nine patients (5.7%). In two of the nine patients, repeat angioplasty involved another lesion. Therefore, the target lesion revascularization rate during follow-up was 4.5% (seven patients). At quantitative coronary angiography, the minimal lumen diameter (mean+/-SD) increased from 1.12+/-0.34 mm before to 2.89+/-0.35 mm after stenting. Repeat angiography at 6 months was performed in 144 patients (92%). The minimal lumen diameter at follow-up was 2.12+/-0.67 mm. Restenosis (diameter stenosis of 50% or more) was documented in 12 patients or 8.3%. When the two patients with documented stent thrombosis are included, the restenosis rate amounts to 97%. CONCLUSIONS: These data confirm that, in selected patients, stents can safely be implanted without the use of systemic anticoagulation, provided optimal stent expansion is achieved. The exact role of intravascular ultrasound in the achievement of these results needs to be established by appropriately designed studies. In the meantime, intravascular ultrasound coupled with the Palmaz-Schatz stent incorporating a spiral bridge, may have contributed considerably to the immediate angiographic outcome, which in turn may explain the favourable clinical and angiographic outcome at 6 months.

Aged↗
PubMed1998

Assessment of the coupling between RTapex and RR interval as an index of temporal dispersion of ventricular repolarization.

To evaluate the dynamic characteristics of the relationship between the RT and RR intervals we analyzed the RR/RTapex variability interaction with a dynamic parametric model whose parameters can be directly estimated from the beat-to-beat series RR and RTapex intervals. The model is designed to separate the fraction of RTapex variability driven by RR changes from that independent of RR variations and to quantify the gain and phase of the relationship between RR and RTapex intervals. The percentage of RTapex variability driven by RR variability was significantly greater in young normal subjects in comparison with postmyocardial infarction patients as well as with age-matched control subjects. This new approach based on the quantification of the RTapex variability dependent and independent of beat-to-beat RR interval changes could be used to quantify the degree of uncoupling between the two signals thus providing a new and noninvasive index of temporal dispersion of ventricular repolarization.

Adult↗
PubMed1998

Procedural and follow up results with a new balloon expandable stent in unselected lesions.

OBJECTIVE: To assess the clinical and angiographic results of the first clinical application of a new balloon expandable stent, the NIR stent, characterised by high longitudinal flexibility and low profile before expansion, and by high radial support and minimal recoil and shortening after expansion. DESIGN: Single centre survey of unselected lesions in consecutive patients. SETTING: Tertiary referral centre. PATIENTS AND LESIONS: 93 stents of various length (9, 16, and 32 mm) were implanted in 64 lesions in 41 patients. Twenty lesions (31%) were longer than 15 mm, and 17 lesions (27%) were located in vessels with a diameter smaller than 2.5 mm. Extreme tortuosity of the proximal vessel was present in 15 lesions (23%). All patients were treated with aspirin and ticlopidine. All lesions were evaluated before and after treatment by quantitative angiography, and in 47 lesions (75%) the stent expansion was also controlled by intracoronary ultrasound. Clinical follow up was available in all patients and angiographic follow up was performed in 53 lesions (84%), at a mean (SD) interval of 5.4 (1.7) months. RESULTS: Deployment of the stent failed in two lesions (3%). Minimum lumen diameter increased from 1.01 (0.54) mm to 2.94 (0.49) mm, and diameter stenosis decreased from 66(15)% to 7(11)%. There was one in-hospital non-Q wave myocardial infarction, one sudden death after 40 days, and 17 target lesion revascularisations (27%). Angiographic restenosis (> or = 50% diameter stenosis) was documented in 19 lesions (36% of all lesions with angiographic follow up), with an average residual diameter stenosis of 43(21)% and minimum lumen diameter of 1.63 (0.74) mm. Restenosis was more common in vessels with a reference diameter < 2.5 mm (45%) and for lesions longer than 15 mm (46%). CONCLUSIONS: The NIR stent could be used successfully in most lesions, achieving optimal angiographic results with very few in-hospital or subacute cardiac events. The angiographic restenosis rate and need for target lesion revascularisation remained high in this unfavourable lesion subset, especially in small vessels and long lesions.

Catheterization↗
PubMed1998

Quantitative description of the morphology of the human palate by a mathematical equation.

OBJECTIVE: To derive a three-dimensional mathematical description of normal human hard tissue palatal size and shape. METHODS: The maxillary dental casts of 30 adolescents free from respiratory problems, who had a complete (28 teeth) permanent sound dentition with normal occlusion, were studied. The x, y, z coordinates of several standardized palatal and dental landmarks were obtained with a computerized three-dimensional digitizer. Palatal landmarks were used to derive a mathematical equation of palatal shape in the frontal and sagittal planes. Palatal width, length, frontal and sagittal heights, and sagittal slope, as well as dental arch transverse and anteroposterior dimensions, were computed. RESULTS: Neither the size nor the shape of the palate was significantly influenced by gender. Only the intercanine distance was larger (p < .025) in males than in females. CONCLUSIONS: Data collected in the present investigation could represent a first database for the quantitative description of normal human palatal morphology in subjects with a complete permanent dentition.

Adolescent↗
PubMed1998

Plaque removal prior to stent implantation in native coronary arteries: why? When? And how?

Coronary stenting has significantly reduced restenosis in focal de novo coronary lesions, but its impact in complex lesions has been less pronounced. Recent data suggest a possible role for pre-intervention plaque burden in exacerbating neo-intimal hyperplasia after stent implantation. These observations formed the basis for the hypothesis that plaque removal prior to stent implantation, using directional atherectomy in non-calcified lesions and rotational atherectomy in calcified lesions, may reduce restenosis. The currently available non-randomized experience that used this approach has shown its feasibility and favourable long-term outcome when applied in selected patients. However, the incidence of non-Q-wave myocardial infarction is increased with both rotational and directional atherectomy compared to PTCA or stent alone. The utilization of potent antiplatelet agents and/or the development of new atherectomy devices that produce lower embolization rate may decrease the incidence of these ischaemic complications. In addition, considering the increased procedural time and cost, this approach will have to be applied in selected patient subsets where debulking or stenting as a stand-alone strategy is associated with a high restenosis rate. Randomized clinical trials testing the usefulness of this approach, with both rotational and directional atherectomy, are currently in progress.

Angioplasty, Balloon, Coronary↗
PubMed1998

Bifurcational stenting.

Treatment of bifurcation lesions is a complex issue, and there is no single panacea to the variety of lesions that form this cohort. The contribution of side-branch compromise to the adverse clinical events occurring after stent implantation need not be stressed and requires an aggressive approach including balloon dilatation before and after stent deployment. Various new techniques of kissing stent placement, such as the 'T', 'V', 'Y', and the culottes technique, have been proposed in recent years to treat different anatomical situations. The angle formed by the side-branches, the severity of involvement of the ostia and the vessel size are the main factors which influence selection of the strategy. Newer generations of stents, such as the bifurcate stents, tailor-made for bifurcation lesions, are evolving, and are expected to make a positive impact on the procedural outcomes and long-term results after bifurcation stenting. The development of new strategies and stent designs has greatly improved safety and immediate outcome of bifurcational stenting, but the procedural success still needs to be matched by an equal improvement in long-term patency.

Angioplasty, Balloon, Coronary↗
PubMed1998

Persistent High Restenosis After Local Intrawall Delivery of Long-Acting Steroids Before Coronary Stent Implantation.

OBJECTIVE: This pilot study was performed to evaluate the feasibility and safety of intrawall delivery of long acting steroids before stent implantation, testing the efficacy of this treatment in reducing intimal hyperplasia in lesions at high risk for restenosis. METHODS: In 24 patients (40 lesions) local intrawall drug delivery of methylprednisolone acetate, using a new catheter device, was attempted before elective stent implantation. Treated lesions were compared to a matched control group. RESULTS: Lesions were classified AHA/ACC type C in 47% of cases, had a mean lesion length of 13.6 +/- 9.1 mm, and a mean vessel diameter of 2.85 +/- 0.44 mm. In 9 cases (25%) chronic total occlusions were treated. Methylprednisolone acetate (mean 60 +/- 23 mg) was delivered in 36 lesions (21 patients; delivery success 90%) in the remaining 4 lesions (10%) the delivery device did not cross the lesion. After drug delivery 46 stents were implanted (1.2 stent/lesion; stented segment length 30.1 +/- 18.8 mm) using high pressure for stent expansion (mean 16.4 +/- 3.1 atm). Intracoronary ultrasound guidance was used in 64% of cases. Procedural and in-hospital complications were: Two non Q wave myocardial infarctions (8%) and one (3%) subacute stent thrombosis. Angiographic follow-up was obtained in all 36 treated lesions (100%) and the angiographic restenosis rate (³ 50% diameter stenosis) was 39%. A reduction of the incidence of restenosis compared to the matched control group was not observed. CONCLUSIONS: Long acting steroids could be delivered locally with high success and low complication rates. The restenosis rate remained high in a subset of unfavorable lesions with high risk for restenosis.

Journal Article↗
PubMed1998

Clinical and Angiographic Results with the Multi-Link Stent Implanted under Intravascular Ultrasound Guidance (West-2 Study).

In view of the side effects of ticlopidine, stenting with the sole use of aspirin as post-stent treatment, has been attempted under the guidance of intravascular imaging to guarantee the optimization of the deployment. It was also hypothesized that optimal stenting under IVUS guidance would subsequently reduce the restenosis rate. With these aims the WEST-2 trial using the ACS MULTI-LINK stent was designed. This stent is composed of multiple corrugated rings connected to multiple links Ñ a design that combines radial strength, flexibility and conformability. In WEST-2, between February 1996 and August 1996, 18 centers enrolled 165 patients with stable or stabilized unstable angina and a single de novo lesion in vessel sizes ³ 2.75 mm. Optimal stenting was assessed using predefined QCA (DS% post-stent ³ 15% and stent/artery ratio ³ 1) and IVUS criteria. Patients fulfilling all criteria were treated with aspirin alone. MACE (death, MI, target lesion revascularization) as well as the restenosis rate were assessed at 6 months. In view of the results it may be concluded that the use of aspirin alone as post-stent treatment is safe when preset IVUS criteria are achieved. The target lesion revascularization rate, the restenosis percentage and the incidence of MACE encountered in this registry are among the lowest observed so far.

Journal Article↗
PubMed1998

Alcoholization of the interventricular septum (Sigwart procedure) for treatment of hypertrophic cardiomyopathy.

A patient with NYHA Class III dyspnea under medical treatment for hypertrophic cardiomyopathy underwent alcoholization of the first septal perforator. The procedure induced complete disappearance of the intraventricular gradient, with development of a Q-wave anterior myocardial infarction (peak CK rise = 1645 IU) and a complete right bundle branch block. After 5 months the patient maintains a marked improvement in functional capacity (NYHA Class I).

Cardiac Catheterization↗
PubMed1998

[A case of congenital hepatic hemangioendothelioma treated with prednisone: the echographic changes and Doppler study].

Imaging investigations and other findings observed in a term infant with a multicentric hepatic hemangioendothelioma, admitted to the Intensive Care Unit at the age of 13 days because of non specified feeding difficulties and dyspnoea, are presented. Physical examination revealed cardiac bruit and congestive heart failure with marked hepatomegaly; in addition there were multiple small skin hemangiomas. Echocardiography was negative, abdominal sonography showed multiple round lesions of mixed echogenicity in the liver, large vascular channels, a right hepatic artery and hepatic veins enlarged, a caliber of the aorta below the level of the superior mesenteric artery reduced. The infant was additionally investigated by whole-body scintigraphy with 99mTc-labeled red blood cells to determine the possibility of coexistence of other visceral hemangiomas and by MR, in which the tumor manifested as multiple well-circumscribed space-occupying nodules of high signal intensity on T2-weighted images with evidence of fast flow. The baby underwent furosemide and steroid therapy: serial two-dimensional US scans showed change in echogenicity, responding to therapy. Doppler sonography has proven to be also very useful in the monitoring therapy determining changes in flow pattern and velocity at the level of hepatic, cerebral and renal vessels: before therapy we observed a reduction of the diastolic flow until the zero line through the internal carotid artery and renal artery with an increase of the Resistance Index. It means that this important component can be compromised in the presence of a hepatic hemangioendothelioma.

Drug Therapy, Combination↗