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Biomedical subjects

A Colombo

Publications and source records attributed to A Colombo.

At least 91 records · Page 5Linked to original sources
PubMed2000

The skirt technique: A stenting technique to treat a lesion immediately proximal to the bifurcation (pseudobifurcation).

We report a new stenting technique employed in 10 patients to treat lesions immediately proximal to a bifurcation (pseudobifurcation). A stent is mounted on two balloon catheters and advanced into the lesion immediately proximal to the bifurcation until the distal portion of the balloon catheters enters each branch at the bifurcation. This is followed by kissing balloon inflation for stent deployment. In all 10 cases, the final angiogram showed a good result at the lesion site and no ostial compromise of any of the branches. Cathet. Cardiovasc. Intervent. 51:347-351, 2000.

Aged↗
PubMed2000

Rotational atherectomy or balloon angioplasty in the treatment of intra-stent restenosis: BARASTER multicenter registry.

The BARASTER registry was formed to evaluate the initial success and long-term results of rotational atherectomy in the management of in-stent restenosis. Rotational atherectomy was used in 197 cases of in-stent restenosis: 46 with stand-alone rotational atherectomy or at most 1 atmosphere of balloon inflation (Rota strategy), and 151 with rotational atherectomy and adjunctive balloon angioplasty <1 atmosphere (Combination strategy). These were compared with 107 episodes of in-stent restenosis treated with balloon angioplasty alone. In this observational study, the use of Combination therapy was associated with a slightly higher initial success rate (95% vs. 87% with the Rota strategy and 89% with Balloons, P = 0.08). There was a reduction in one year clinical outcomes (death, myocardial infarction or target lesion revascularization) in the combination group (38% vs. 60% with Rota and 52% with balloons, P = 0.02). These data support a benefit of the strategy of debulking with rotational atherectomy followed by adjunctive balloon angioplasty, in the management of in-stent restenosis.

Aged↗
PubMed2000

Lack of NO Formation Is Involved in the Vasodilative Response to Contrast Media.

Intravascular injection of angiographic contrast media results in peripheral vasodilation and hypotension. The mechanisms underlying these hemodynamic changes are not entirely clear. We hypothesized that increased formation of nitric oxide (NO) could be involved in the vasodilatory response to contrast media. To address this assumption we have investigated whether N(G)-monomethyl-L-arginine (L-NMMA, 200 mg/kg) and N(G)-nitro-L-arginine methyl ester (L-NAME, 50 mg/kg), two specific NO formation inhibitors, can abolish the hypotensive response to intravascular injection of isopaque amin (1 g/kg), a contrast medium, as well as bradykinin (10 µg/kg), a NO-dependent vasodilator, in anaesthetized normotensive rats. In rats before pretreatment with L-NMMA and L-NAME, the absolute values of the average fall in mean arterial pressure (MAP) induced by intravascular injection of isopaque amin and bradykinin were 21.3 +/- 2.1 and 37.2 +/- 4.4 mmHg, respectively. Pretreatment with L-NMMA and L-NAME failed to affect the hypotensive response to isopaque amin; by administering isopaque amin in rats pretreated with L-NMMA and L-NAME the absolute values of the average fall in MAP were 25.6 +/- 4.9 and 23.4 +/- 3.9 mmHg, respectively, similar to the average fall in MAP before treatment with NO formation inhibitors. In contrast, the hypotensive response to bradykinin was significantly inhibited; by administering bradykinin in rats pretreated by L-NMMA and L-NAME, the absolute values of the average fall in MAP were 10.2 +/- 2.8 and 7.2 +/- 2.2 mmHg, respectively, much less than the average fall in MAP before treatment with NO formation inhibitors. We conclude that intravascular injection of isopaque amin causes reduction in systemic arterial pressure. However, this vasodilative effect seems unrelated majorly to augmented endothelium-derived NO formation.

Journal Article↗
PubMed2000

Hereditary surfactant protein B deficiency resulting from a novel mutation.

Hereditary surfactant protein B (SP-B) deficiency is an autosomal recessive disease in which affected infants are unable to produce normally functional surfactant, resulting in neonatal respiratory failure and death within the first year of life. The most common cause of SP-B deficiency is a frameshift mutation in exon 4 (121ins2) of the SP-B gene. We report a newborn infant who had onset of respiratory distress during the first days, was unresponsive to exogenous surfactant, corticosteroids, prostacyclin, high frequency oscillatory ventilation and inhaled nitric oxide, and died after 27 days. Immunostaining of lung tissue obtained at biopsy demonstrated absent staining for SP-B, and robust extracellular staining for proSP-C, findings characteristic for SP-B deficiency. DNA analysis revealed the 121ins2 mutation on one of her SP-B alleles and a novel mutation, 122delC, on her other SP-B allele. The proximity of the novel mutation in exon 4 allele found in this infant to the 121ins2 supports the notion that this region may represent a "hot spot" for SP-B gene mutations and confirms the heterogeneity of mechanisms which lead to SP-B deficiency. Hereditary SP-B deficiency is a rare, newly diagnosable and probably under-recognized disease, which should be suspected in term newborn infants with unexplained respiratory failure.

Base Sequence↗
PubMed2000

Early translaryngeal tracheostomy in patients with severe brain damage.

OBJECTIVES: To describe the effects of early translaryngeal tracheostomy on intracranial pressure (ICP), cerebral perfusion pressure (CPP), and jugular bulb saturation (SjO2); to identify the main mechanisms affecting ICP during tracheostomy; and to evaluate the long-term effects of tracheostomy on tracheal anatomy and function. DESIGN: Prospective, observational, clinical study. SETTING: Neurosurgical intensive care unit in a teaching hospital. PATIENTS: 20 patients admitted to the ICU because of head injury, subarachnoid hemorrhage, or brain tumor with a Glasgow Coma Scale less than 8. INTERVENTIONS: Patients underwent translaryngeal tracheostomy under strict neuromonitoring. MEASUREMENTS AND RESULTS: ICP rose significantly (p < 0.05) at the critical time of cannula placement while all other parameters remained stable. At this time five patients suffered intracranial hypertension (ICP > 20 mmHg). In one of them CPP dropped below 60 mmHg. Arterial CO2 tension (PaCO2) did not rise significantly. No other major complications were recorded during the procedures. Three months after tracheostomy normal findings were detected by tracheoscopy in all cases (11 patients could be examined). CONCLUSIONS: Translaryngeal tracheostomy, performed in selected patients when the risk of intracranial hypertension was reduced to the minimum, was well tolerated in the majority of cases and did not induce persistent intracranial disorders. However, ICP is affected by tracheostomy, and careful monitoring and patient selection is necessary. At follow-up no severe anatomical or functional damage was detected.

Adolescent↗
PubMed2000

Bifurcation lesions: two stents versus one stent--immediate and follow-up results.

OBJECTIVES: The purpose of this study was to evaluate two different techniques of stent placement in bifurcation lesions. BACKGROUND: Although stent placement with dedicated techniques has been suggested to be a useful therapeutic modality for bifurcation lesions, limited information is available if stent placement on the side branch and on the parent branch provides any advantage over a simpler strategy of stenting the parent vessel and balloon angioplasty of the side branch. METHODS: Between March 1993 and April 1999, we treated a total of 92 patients with bifurcation lesions with two strategies: stenting both vessels (group B, n = 53) or stenting the parent vessel and balloon angioplasty of the side branch (group P, n = 39). Paired angiograms were analyzed by quantitative angiography, and clinical follow-up was obtained. RESULTS: Stent placement on both branches resulted in a lower residual stenosis (7.4 +/- 10.9% vs. 23.4% +/- 18.7%, p < 0.001) in the side branch. Acute procedural success was similar in the two groups (group B: 87% vs. Group P: 92%). In-hospital major adverse cardiac events (MACE) occurred only in group B (13% vs. 0%, p < 0.05). At the six-month follow-up, the angiographic restenosis rate (group B: 62% vs. Group P: 48%) and the target lesion revascularization rate (38% vs. 36%, respectively) were similar in the two groups. There was no difference in the incidence of six-month total MACE (51% vs. 38%). CONCLUSIONS: For the treatment of true bifurcation lesions, a complex strategy of stenting both vessels provided no advantage in terms of procedural success and late outcome versus a simpler strategy of stenting only the parent vessel.

Aged↗
PubMed2000

Hemimegalencephaly in hypomelanosis of Ito: early sonographic pattern and peculiar MR findings in a newborn.

Sonography is a reliable tool for the evaluation of the most severe congenital abnormalities of the brain; in the present case it provided an early demonstration of hemimegalencephaly in hypomelanosis of Ito in a newborn affected by body hemihypertrophy and skin lesions. Serial magnetic resonance (MR) examinations confirmed the asymmetry of the cerebral hemispheres, and documented the evolution of the hemispheric growth and the presence of unusual aspects.

Brain↗
PubMed2000

Pulmonary toxicity following carmustine-based preparative regimens and autologous peripheral blood progenitor cell transplantation in hematological malignancies.

Sixty-five patients with hematological malignancies (25 multiple myeloma, 18 Hodgkin's disease, 22 non-Hodgkin's lymphomas) who received a carmustine-based regimen followed by autologous PBPC transplantation, were studied retrospectively to evaluate the incidence of post-transplant non-infective pulmonary complications (NIPCs), risk factors predictive of NIPCs, and response to steroids. Carmustine (BCNU) given i.v. at a dose of 600 mg/m2 was combined with etoposide and cyclophosphamide in 40 patients (BCV regimen) and with etoposide and melphalan in 25 patients (BEM regimen). Seventeen of 65 patients (26%) had one episode of NIPCs. The median time to NIPCs was 90 days (52-289). Factors that increased the risk of developing NIPCs on multivariate analysis were female sex (P < 0. 001) and BCV regimen (P < 0.05). All patients with NIPCs received prednisone at a dose of 1 mg/kg body weight for 10 days then tapered by 5 mg every two days; complete response to steroids was achieved in 15 of 17 patients; one unresponsive patient died of interstitial pneumonia. BCNU given at the dose of 600 mg/m2 is well tolerated when associated with melphalan and etoposide. In females and in patients receiving BCNU with cyclophosphamide, a BCNU dose reduction may be advisable. Bone Marrow Transplantation (2000) 25, 309-313.

Adolescent↗
PubMed2000

An electromyographic investigation of masticatory muscles symmetry in normo-occlusion subjects.

The influence of occlusal conditions on stomatognathic function can be assessed by electromyography. Electromyographic activity of left and right temporal and masseter muscles was recorded in 30 young healthy adults with a normal occlusion during: (1) a 3-s maximum voluntary clench on cotton rolls positioned on the posterior teeth (standardization recording); (2) a 3-s maximum voluntary clench in intercuspal position; and (3) a 3-s alternate 'maximum' voluntary contraction and relaxation with a 1 Hz frequency. All potentials were standardized as a percentage of the maximum potential of test 1. Waveforms of paired muscles were compared by computing a percentage overlapping coefficient (ratio between each 50-ms overlapped areas and the total areas, up to 100% for symmetric muscles). Waveforms were also analysed for a laterodeviating effect on the mandible given by unbalanced muscular couples, and a torque coefficient (up to 100% for a significant laterodeviating couple on the mandible) was computed. In all subjects, both tests were performed with symmetric muscular patterns (more than 88%) and with negligible laterodeviating couples on the mandible (lower than 10%). The two coefficients allow an assessment of muscular asymmetry during static and dynamic clenching tests, and, together with the standardization of the potentials, could be a useful tool to detect functionally altered occlusal conditions, i.e. conditions where an apparent good morphological situation is not related to a correct neuromuscular status.

Adolescent↗
PubMed2000

Normal growth and development of the lips: a 3-dimensional study from 6 years to adulthood using a geometric model.

A 3-dimensional computerised system with landmark representation of the soft-tissue facial surface allows noninvasive and fast quantitative study of facial growth. The aims of the present investigation were (1) to provide reference data for selected dimensions of lips (linear distances and ratios, vermilion area, volume); (2) to quantify the relevant growth changes; and (3) to evaluate sex differences in growth patterns. The 3-dimensional coordinates of 6 soft-tissue landmarks on the lips were obtained by an optoelectronic instrument in a mixed longitudinal and cross-sectional study (2023 examinations in 1348 healthy subjects between 6 y of age and young adulthood). From the landmarks, several linear distances (mouth width, total vermilion height, total lip height, upper lip height), the vermilion height-to-mouth width ratio, some areas (vermilion of the upper lip, vermilion of the lower lip, total vermilion) and volumes (upper lip volume, lower lip volume, total lip volume) were calculated and averaged for age and sex. Male values were compared with female values by means of Student's t test. Within each age group all lip dimensions (distances, areas, volumes) were significantly larger in boys than in girls (P < 0.05), with some exceptions in the first age groups and coinciding with the earlier female growth spurt, whereas the vermilion height-to-mouth width ratio did not show a corresponding sexual dimorphism. Linear distances in girls had almost reached adult dimensions in the 13-14 y age group, while in boys a large increase was still to occur. The attainment of adult dimensions was faster in the upper than in the lower lip, especially in girls. The method used in the present investigation allowed the noninvasive evaluation of a large sample of nonpatient subjects, leading to the definition of 3-dimensional normative data. Data collected in the present study could represent a data base for the quantitative description of human lip morphology from childhood to young adulthood.

Adolescent↗
PubMed2000

Atherectomy plus stenting: what do we gain?

Coronary stents have improved the short and long-term outcomes of selected patients undergoing catheter-based coronary interventions. However, the use of these devices in complex coronary lesions has also created an incessant form of in-stent restenosis that still defies treatment. Plaque burden has been recognized as an important factor that may incite neo-intimal proliferation after stent implantation. Prospective non-randomized experience has shown that plaque removal prior to stent implantation using directional atherectomy is a promising approach to reduce restenosis in selected patients. However, the proof of concept awaits the results of the randomized trials. Ultimately, the clinical utility of this approach will depend upon: (1) further improvements on the current directional atherectomy device; (2) minimizing the incidence of non-Q-wave myocardial infarction with selective use of IIb-IIIa platelet receptor antagonists or distal protection devices; (3) targeting patients at high risk for restenosis in whom efficient debulking is feasible such as non-calcified lesions in vessels >2.75 mm and <3.5 mm in diameter that require long stents, aorto-ostial lesions, bifurcational lesions, and chronic total occlusions.

Atherectomy, Coronary↗
PubMed2000

Multicenter evaluation of the phosphorylcholine-coated biodivYsio stent in short de novo coronary lesions: The SOPHOS study.

AIMS: The BiodivYsio trade mark stent (Biocompatibles Ltd, Farnham, UK) is coated with a phosphorylcholine (PC)-containing copolymer to confer biocompatibility. The SOPHOS (Study Of PHosphorylcholine coating On Stents) study was designed to assess the safety and efficacy of this novel coronary stent and by indirect comparison to indicate equivalence with other formal stent studies. METHODS AND RESULTS: Patients with angina and a single short (#x2A7F;12 mm) de novo lesion in a native coronary artery of >/=2.75 mm diameter were included. A total of 425 patients were allocated in 24 centers. Clinical data were collected at one-, six- and nine-month follow-up. Angiography was performed before and after the stent implantation. In addition, in the first 200 patients (SOPHOS A) angiography was routinely performed at six months. The following 225 patients (SOPHOS B) were merely followed up clinically. The primary end-point of the study, the six-month MACE-rate (MACE = Major Adverse Cardiac Events) was 13.4% (two cardiac death; five Q-wave/nine non-Q-wave myocardial infarctions (MI); nine CABG and 32 target lesion revascularization (TLR), which is similar to the calculated 15% MACE-rate in comparable reference studies. Secondary end-points included among others restenosis at six months in the SOPHOS A population. The target vessel diameter was 2.98 +/- 0.48 mm. Minimal lumen diameter pre/post procedure and at follow-up was 1.00 +/- 0.32, 2.69 +/- 0.37, 1.91 +/- 0.71 mm, respectively. The binary restenosis rate (>/=50% diameter stenosis at follow-up) was 17.7%. CONCLUSION: The coronary BiodivYsio stent is safe and effective as a primary device for the treatment of native coronary artery lesions in patients with stable or unstable angina pectoris. Clinical and angiographic results are in the statistical range of equivalence with comparable studies with other current stents.

Journal Article↗
PubMed2000

Multispectral imaging approach in the diagnosis of cutaneous melanoma: potentiality and limits.

In an attempt to overcome the subjectiveness of clinical observation in the diagnosis of cutaneous melanoma, a computerized method is proposed. Reflectance images of 237 pigmented lesions (67 melanomas and 170 non-melanomas) were analysed using a telespectrophotometric technique. This device consists of a CCD camera with 17 interference filters. Images were acquired at selected wavelengths, from 420 to 1040 nm. Morphological and reflectance related parameters were extracted from the wavelength-dependent images of the lesions. The most significant features in the comparison between benign and malignant lesions were: lesion dimension (P < 10(-8) at 578 nm); mean value (P < 10(-7) at 940 nm) and standard deviation (P < 10(-4) at 904 nm) of lesion reflectance; lesion roundness (P < 10(-5) at 461 nm); and border irregularity (P < 10(-4) at 461 nm). Based on these parameters, a discriminant function between the two populations of lesions (naevi and melanomas) was obtained. By using the results of the analysis of the recruited lesions as 'training data', discriminant functions enabled the assignment of a score, or a 'risk probability', to each studied lesion. By imposing a sensitivity of 80% (a figure that mimics the diagnostic capability of an experienced clinician), entering or not entering the lesion dimension as input data in the discriminant analysis led to a specificity of 51% or 46% respectively. The high number of false-positive cases, which is a consequence of the selection criteria of the lesions, is, at present, the major limitation of the current technique. Nevertheless, our results suggest that an imaging-based computer-assisted device could be capable of discriminating malignant lesions mainly by evaluation of reflectance, especially in the infrared region, and shape properties. The dimension of a lesion should not be essential in the diagnosis of melanoma and, in our opinion, small melanomas should be recognized by a computer system as well as they are on clinical grounds.

Adolescent↗
PubMed2000

Mass volume measurement in severe head injury: accuracy and feasibility of two pragmatic methods.

OBJECTIVE: To assess the clinical feasibility and the accuracy of two pragmatic methods in comparison with a conventional computer based method of measurement of masses from CT. METHODS: Nineteen CT scans of 11 patients with severe head injury, showing 34 traumatic lesions, were examined. The volume of every lesion was digitally measured, then a panel of three examiners independently repeated the measurement using the ellipsoid and the Cavalieri method in random order. RESULTS: All the lesions were identified by all the readers and the mean volume measured by each examiner differed by less than 1.5 ml. The average reading time for each scan was 4 minutes for the ellipsoid and 7 minutes for the Cavalieri method. The average volume of the lesions was 34.2 (SD 35) ml with the digital system, and 38.4 (SD 41) ml and 34.8 (SD 36) ml for the ellipsoid and the Cavalieri readings respectively. The average difference between the applied technique and the digital system was 0.57 (SD 9.99) ml for the Cavalieri direct estimator and 0.20 (SD 15.48) ml for the ellipsoid method. The 95% confidence interval for this difference fell between -2.75 and 3.89 ml for the Cavalieri, and between -4.94 and 5.35 ml for the ellipsoid method. There were 19 lesions >25 ml; the ellipsoid method identified 16 of them, whereas 17 were classified with the Cavalieri method. When considering individual lesions rather than the average volume, discrepancies were detected with both methods. The ellipsoid method was less precise, especially when extracerebral lesions were measured. CONCLUSIONS: Both pragmatic methods are inferior to computer based reading, which is the choice when accurate volume estimation is necessary. However, if a digital volumetric determination of the lesions using a CT computer is not possible, the two pragmatic methods offer an alternative.

Analysis of Variance↗
PubMed2000

Progressive decrease of outflow gradient and septum thickness after percutaneous alcoholization of the interventricular septum in hypertrophic obstructive cardiomyopathy.

BACKGROUND: The aim of this study was to evaluate the immediate- and mid-term results of percutaneous transluminal septal myocardial ablation (PTSMA) of the interventricular septum performed in 15 consecutive patients with hypertrophic obstructive cardiomyopathy between 1996 and 1999. METHODS: Prior to intervention, all patients (7 males, 8 females, mean age 62 +/- 11 years) complained of severe dyspnea (NYHA functional class III-IV) despite medical treatment with beta-blockers and/or verapamil. Family history of hypertrophic cardiomyopathy was present in 2 cases. Dehydrated alcohol (4.8 +/- 1.5 ml/pt) was selectively infused into the first septal perforator artery through over-the-wire balloon catheters. In 5 patients a second or a third septal branch was treated because the intraventricular gradient persisted above 50 mmHg after the initial alcohol infusion. RESULTS: Alcohol infusion induced an average peak creatine phosphokinase level of 1,524 +/- 427 IU/l. No iterating ventricular arrhythmias occurred during the procedure or in the 2-3 days of continuous ECG monitoring after the procedure. Two patients (13%) developed a complete atrioventricular block after the procedure, requiring permanent double-chamber pacing. Electrocardiographic changes included a > 2 mm ST segment elevation and transient right bundle branch block or left anterior/left posterior hemiblock in all patients. Peak basal intraventricular gradient decreased from 80 +/- 27 to 24 +/- 27 mmHg (p < 0.01) during cardiac catheterization and from 81 +/- 27 to 35 +/- 25 mmHg (p < 0.01) at the echocardiographic control performed during the hospital stay. At follow-up (mean 5.1 +/- 3.6 months), all patients were in NYHA functional class I or II. Repeat echocardiography showed a further significant decrease in intraventricular gradient to 25 +/- 26 mmHg (p < 0.01) and a progressive decrease in intraventricular septum thickness (25 +/- 5 mm before treatment, 21 +/- 6 mm before hospital discharge, 17 +/- 3 mm at follow-up, p < 0.01). CONCLUSIONS: PTSMA of the intraventricular septum effectively relieves symptoms in selected patients with hypertrophic obstructive cardiomyopathy. The immediate decrease in intraventricular gradient is followed by a further decline at follow-up with a progressive reduction in the intraventricular septum thickness.

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