PubMed Health⌕ Search

Biomedical subjects

A Colombo

Publications and source records attributed to A Colombo.

At least 235 records · Page 13Linked to original sources
PubMed1997

Effect of growth and development on cephalometric shapes in orthodontic patients: a Fourier analysis.

The age- and gender-related shape variations of the craniofacial skeleton in skeletal Class I children were quantified using a Fourier analysis on the pre-treatment lateral head films of 122 orthodontic patients (age range 7-15 years), who were subdivided into six groups for sex and age (2-year intervals). Seven landmarks representative of the maxillo-mandibular sagittal and vertical relationship were identified and digitized. The contiguous landmarks were connected by segments, the form was normalized with respect to its orientation and size, and a Fourier analysis of the contour was performed. Mean values of the cosine and sine coefficients of the first six harmonics in the sex and age classes were computed. The size-standardized outlines of the oldest boys were narrower and longer than the outlines of the youngest boys (differences at gonion, menton, sella and nasion). Shape differences between mean plots in girls were negligible. In the youngest patients, girls had a larger size-independent shape in the mandibular region; their shape was narrower (anterior-posterior direction) and longer (vertical direction) than male shape. In the oldest patients, boys had a larger size-independent shape at gonion, and a narrower shape at articulare and pogonion than girls. Size increased from the youngest to the oldest boys; size differences were not conspicuous in girls. Within an age class, male size was always larger than female. Fourier analysis allowed a global evaluation of the cephalometric forms, with separate quantifications of the age- and gender-related differences in size and shape.

Adolescent↗
PubMed1997

Non-specific airway hyperresponsiveness in mono-sensitive Sicilian patients with allergic rhinitis. Its relationship to total serum IgE levels and blood eosinophils during and out of the pollen season.

BACKGROUND: Initial attempts to evaluate the association between allergic rhinitis and non-specific bronchial responsiveness has produced conflicting results. In fact, some studies showed a strong correlation and other failed to find an association. However, little is known about the effect of natural specific allergen exposure on the bronchial reactivity of mono-sensitive patients with rhinitis in the southern Mediterranean area, in relation to skin reactivity to allergens, total serum IgE levels and blood eosinophils. OBJECTIVES: The significance of the association between allergic rhinitis, and abnormal airway responsiveness with regard to the pathogenesis of asthma is unclear. For this reason, we have studied non-specific bronchial hyperreactivity, in patients with seasonal allergic rhinitis, with reference to the responsible allergen. The aim of the study was to correlate the responsiveness to bronchoprovocation with methacholine in subjects a with allergic rhinitis during and out of the pollen season with total serum IgE and blood eosinophils. METHODS: Fourty-nine non-smoking patients with clinical diagnosis of allergic rhinitis and mono-sensitive skin-prick tests to pollen allergens were enrolled in the study. Twenty patients suffered from seasonal rhinitis to Parietaria pollen, 15 patients to Gramineae pollen and 14 patients to Olea pollen. In all patients lung function measurements (assessed as response to methacholine), total serum IgE and blood eosinophil counts were measured during and out of the pollen season. RESULTS: During pollen season, 16 out of 49 rhinitis patients demonstrated values of bronchial responsiveness measured as response to inhaled methacholine in the asthmatic range whereas out of the pollen season only eight patients were in the asthmatic range. By analysing the results with reference to the responsible allergen, during the pollen season 15 out of 16 patients were Parietaria-sensitive and out of the pollen season seven out of eight patients. Finally, in Parietaria-sensitive rhinitis bronchial responsiveness significantly correlated, during and out of the pollen season, with total serum IgE and with blood eosinophil counts. CONCLUSIONS: Our results are consistent with the hypothesis that Parietaria is more important than Olea and Gramineae as a risk for developing non-specific bronchial hyperresponsiveness. On the whole, present observations provide further evidence that there is an interrelationship of allergen kind, total serum IgE, eosinophil and bronchial hyperresponsiveness suggesting that they may play a role in the development of bronchial asthma in rhinitis patients.

Adult↗
PubMed1997

Immunogenicity and antigenicity of a partially hydrolyzed cow's milk infant formula.

We evaluated the immunogenicity and antigenicity of a formula based on partially hydrolyzed cow's milk whey protein in infants at risk of atopy and in controls. Total IgE and specific IgE, IgG, and IgG4 subclass antibodies against egg albumin and cow's milk alpha-lactalbumin, casein, and beta-lactoglobulin were measured by radioimmunoassay of cord blood and of peripheral blood at 5 days and 6 months of life in five groups of infants: 16 breast-fed infants at risk of atopy (group 1), 21 partially hydrolyzed whey formula-fed infants at risk of atopy (group 2), 14 formula-fed infants at risk of atopy (group 3), 10 breast-fed control infants (group 4), and 13 formula-fed control infants (group 5). Total IgE concentration was significantly lower in group 2 at 6 months than in groups 3 and 5 infants and similar to that observed in groups 1 and 4 infants. The concentration of specific antiegg and anti-cow's milk protein IgG and of specific anti-cow's milk alpha-lactalbumin and beta-lactoglobulin IgG4 subclass antibodies was significantly reduced in group 2 as compared to group 3 infants and similar to that found in breast-fed infants. In conclusion, the partially hydrolyzed formula was less immunogenic and antigenic than a traditional formula and was as immunogenic and antigenic as breast milk.

Allergens↗
PubMed1997

Intracoronary stent implantation in native coronary arteries and saphenous vein grafts: a consecutive experience with six types of stents without prolonged anticoagulation.

OBJECTIVE: To analyze the results of implantation of six different intracoronary stents without the use of prolonged anticoagulation. MATERIAL AND METHODS: Between Mar. 30, 1993, and Jun. 30, 1995, 889 patients with 1,194 coronary or vein graft lesions underwent implantation of one of six types of stents-Palmaz-Schatz, Gianturco-Roubin, Wiktor, Micro, Cordis, or Wallstent. The patients were classified into seven groups on the basis of the type of stent that was implanted, including one group with combined use of two or more types of stents. Among the 851 patients with successful stent delivery and without major complications, 801 received only antiplatelet therapy, and 50 received a standard anticoagulation regimen. One-month clinical followup data were obtained in all patients, and clinical events were investigated. RESULTS: The mean number of stents was 1.8 per lesion and 2.4 per patient. Procedural success was achieved in 93% of the lesions. The clinical success rate at 1 month was 90%. Intravascular ultrasound assessment was performed in 90% of the lesions. The final minimal luminal cross-sectional area of the stent increased from 6.8 to 7.8 mm2 after intravascular ultrasound-guided optimization. Within 1 month, 16 stent thrombosis events (1.9%) occurred. No significant differences were noted in stent thrombosis rates among the various stent cohorts. Multivariate logistic regression analysis revealed that the final stent minimal luminal diameter measured by intravascular ultrasonography was the only variable associated with stent thrombosis. CONCLUSION: This study showed that six different stents could possibly be inserted without subsequent anticoagulation if optimal stent expansion and total lesion coverage were achieved.

Anticoagulants↗
PubMed1997

Coronary stenting in 1000 consecutive patients. Long-term clinical and angiographic results.

Coronary stent implantation has become an accepted treatment for selected patients but the long-term outcome after stent implantation has not been investigated in a large unselected population. This study reports clinical and angiographic results after coronary stent implantation in a consecutive group of 1000 patients treated between November 1989 and June 1994. A total of 2012 stents were implanted in 1216 lesions. The anticoagulation regimen after successful stenting was abolished in the last 499 patients, treated with aspirin and ticlopidina. Complex lesions (type B2, type C lesions and chronic total occlusions) were less frequent in the group with anticoagulation (67%, 355/529 lesions) than in the group without anticoagulation (76%, 485/641; p < 0.01). Vessel size was also significantly smaller in the group with no anticoagulation (3.21 +/- 0.50 mm vs 2.89 +/- 0.70 mm; p < 0.001). Procedural success was achieved in 96% of cases. Major complications occurred in 49 pts, including death (1%), emergency bypass surgery (2.7%), and myocardial infarction (2.1%). Subacute stent thrombosis, observed in 2.6% of the patients treated with anticoagulation, decreased to 1% in the last 499 patients receiving only antiplatelet drugs after high pressure stent expansion controlled with intravascular ultrasound (p < 0.05). Angiographic follow-up was obtained at a mean interval of 6.6 +/- 3.0 months in 718 patients (75% of the eligible candidates). The global restenosis rate (greater than 50% diameter stenosis) was 22%, with no statistically significant difference in patients with and without anticoagulation after stenting. Clinical follow-up was available in 890 patients at a mean interval of 14 +/- 17 months. Late cardiac events occurred in 251 patients and included: 159 repeat coronary angioplasties for restenosis (20%), 114 coronary angioplasties for de novo lesions (10%), 33 elective by-pass surgery operations (3.7%) and 42 late deaths (4.7%). At the most recent follow-up there were 719 pts (81%) free of anginal symptoms, including patients having repeat angioplasty for restenosis or disease progression. Coronary stenting has a low incidence of procedural complications and high-pressure ultrasound guided implantation has drastically reduced the risk of subacute thrombosis. Repeat procedures due to restenosis remain the most important limitation of the technique and do not seem to be affected by evolving technique and operator experience.

Angioplasty, Balloon, Coronary↗
PubMed1997

Subintimal stent implantation for the treatment of a chronic coronary occlusion.

Subintimal passages of the guide wire during mechanical recanalization of chronic coronary occlusions are frequent and may result in the inability to reestablish anterograde flow in the distal coronary lumen. By using coronary stents, a conduct through the subintimal pathway can be obtained, allowing long-term restoration of the anterograde blood flow. We report on a case of a long, subintimal vessel reconstruction of a five-year-old coronary occlusion. Under intravascular ultrasound guidance, multiple coronary stents were implanted and good procedural and long-term clinical and angiographic results were achieved.

Aged↗
PubMed1997

The relationship between facial 3-D morphometry and the perception of attractiveness in children.

The aim of this investigation was to determine whether attractive children differ in their three-dimensional facial characteristics from nonattractive children of the same age, race, and sex. The facial characteristics of 36 boys and 44 girls aged 8 to 9 years were investigated. Frontal and profile photographs were analyzed independently by 21 judges, and, for each view, four groups were obtained: attractive boys, nonattractive boys, attractive girls, and nonattractive girls. For each child, the three-dimensional coordinates of 16 standardized soft tissue facial landmarks were automatically collected using an infrared system and used to calculate several three-dimensional angles, linear distances, and linear distance ratios. Mean values were computed in the eight groups, and attractive and nonattractive children were compared within sex and view. Most children received a different esthetic evaluation in the separate frontal and profile assessments; concordance in both attractive and nonattractive groups was only 50%. Moreover, three-dimensional facial morphometry was not able to separate attractive and nonattractive children.

Adult↗
PubMed1997

First experience with imaging core wires.

This study is the first assessment of feasibility and clinical usefulness of an imaging wire. The device used is a 0.018" flexible cable mounting a 30 MHz piezoelectric crystal at the end. The only possible application of the wire in its current configuration is the assessment of balloon expansion with over-the-wire balloon catheters. In this study, 17 lesions were examined in 14 patients. Despite careful removal of the air, no image could be obtained with the balloon deflated or through the shaft of conventional balloon catheters. When the balloon was inflated to 1-4 atm the circular echo-free cross-section of the balloon became visible, surrounded by the dense line of the balloon membrane and by the vessel wall. By examining the stent area at different balloon pressures, it was possible to determine the stent recoil between maximal balloon expansion and lowest balloon pressure allowing a readable ultrasound image. These encouraging preliminary observations confirm the feasibility of the use of an ultrasound guidewire for monitoring balloon expansion during stent implantation. After high pressure inflation, a moderate reduction of the stent lumen was observed during deflation, compatible with the small recoil predicted for the stainless-steel mesh stent used.

Angioplasty, Balloon, Coronary↗
PubMed1997

[An index of daily intensive care unit activity].

OBJECTIVE: To set up an index for the evaluation of type of interventions and procedures applied a prerequisite for the evaluation of appropriateness of ICU's activity. DESIGN: Observation prospective study. PATIENTS: 2507 patients out of the 5030 enrolled in the cohort study. MEASUREMENTS: A cross-sectional assessment of the volume and intensity of treatment--level of care--delivered to patients was performed at a preidentified index day. A check list of procedures was utilized. Intensive high level treatment was demonstrated by the application of procedures suggesting one or more organs or vital functions intensively supported. Sub-intensive treatment was defined by the application of procedures indicating monitoring or treatments not exclusively performed in intensive environment. RESULTS: 3955 samples were collected over 9 index days; 2707 (68.3%) resulted in intensive, 1227 (30.7%) subintensive or intermediate and 41 (1%) ward treatments. Out of the intensive samples, 63.4% received only one intensive procedure, while 27.9% two. Ventilatory support was the most frequently (90.4%) utilized intensive procedure. Overall 99% of the samples were characterized by treatments/procedures too invasive for normal ward. CONCLUSIONS: The proposed method gives the opportunity to easily evaluate the level of care and then the appropriateness of ICU care.

Cross-Sectional Studies↗
PubMed1996

Subacute stent thrombosis and the anticoagulation controversy: changes in drug therapy, operator technique, and the impact of intravascular ultrasound.

Clinical trials have shown that stents are superior to other catheter-based coronary interventions in terms of reduced complications and improved long-term efficacy. With utilization of high-pressure balloon inflation and intravascular ultrasound (IVUS) guidance, stent implantation can now be performed safely without anticoagulation (i.e., with lower rates of stent thrombosis and vascular complications). In 2 recent prospective clinical trials, stent thrombosis occurred in 3.5% of cases despite anticoagulant therapy, which resulted in an average of 7% vascular and bleeding complications. Initial use of IVUS during traditional stent deployment showed that 80% of stents were underexpanded and led to the hypothesis that stent thrombosis might be decreased as a result of optimal stent placement under IVUS guidance without the need for anticoagulation. In a prospective clinical trial to test this hypothesis, three factors were found to reduce stent thrombosis: full stent expansion, complete apposition to the vessel wall, and full lesion coverage. Predictors of thrombotic risk in this era of high-pressure stent deployment without anticoagulation include low ejection fraction, residual dissections, slow flow, multiple stents per lesion, and smaller postprocedure stent luminal diameter. To optimize stent expansion, stent dilation should be performed using a mean inflation pressure of 18 atm with a noncompliant or minimally compliant balloon sized to the vessel being treated (B/V ratio = 1.1). Controversy still remains about the best poststent antiplatelet regimen, and results of a recent trial should indicate whether heparin coating provides additional protection from stent thrombosis.

Anticoagulants↗
PubMed1996

Interaction of ionizing radiation with topotecan in two human tumor cell lines.

The effect of topotecan, a topoisomerase I inhibitor, on ionizing radiation-induced cytotoxicity was studied in 2 human tumor cell lines characterized by a different expression of the target enzyme. The cytotoxicity of topotecan alone or in combination with radiation was assessed in exponentially growing non-small-cell lung cancer (H460) and glioblastoma (GBM) cells using the colony-forming assay. An isobologram method was used to evaluate the treatment interaction. An apparent supra-additive effect in cell killing following drug-radiation-combined treatment was observed only in GBM cells exposed to topotecan for 24 hr. In the case of H460 cells, interaction varied from a strong infra-additive effect at low radiation doses to a slight supra-additive effect when cells were exposed to radiation doses greater than 3 Gy. Northern blot analysis indicated that topoisomerase I expression in H460 cells was 8-fold higher than that of GBM cells. Although the H460 cell line exhibited an increased sensitivity to topotecan, only in the GBM cell line (which expressed a lower level of topoisomerase I) did the drug potentiate the radiation cytotoxicity. The observation that the radiosensitization by topotecan was related to topoisomerase I level is consistent with a putative role of the enzyme in processes involved in the repair of radiation damage. It is conceivable that the modulation of enzyme function results in an effective reduction of cellular capability for repair of radiation damage only if the enzyme is not over-expressed. Although a precise role of topoisomerase I in the cellular response to ionizing radiations (in particular, in DNA repair) remains to be documented, such results suggest the potential interest of topoisomerase I inhibitors in combination with radiation therapy for tumors expressing low topoisomerase I levels.

Antineoplastic Agents↗
PubMed1996

Heparin-coated Palmaz-Schatz stents in human coronary arteries. Early outcome of the Benestent-II Pilot Study.

BACKGROUND: The purpose of the Benestent-II Pilot Study was to evaluate the safety of delaying and eliminating anticoagulant therapy in patients receiving a heparin-coated stent in conjunction with antiplatelet drugs. METHODS AND RESULTS: The study consisted of three initial phases (I, II, III) during which resumption of heparin therapy after sheath removal was progressively deferred by 6, 12, and 36 hours. In phase IV, coumadin and heparin were replaced by 250 mg ticlopidine and 100 mg aspirin. Of the 207 patients with stable angina pectoris and a de novo lesion in whom heparin-coated stent implantation was attempted, implantation was successful in 202 patients (98%). Stent thrombosis did not occur during all four phases, and the overall clinical success rate at discharge was 99%. Bleeding complications requiring blood transfusion or surgery fell from 7.9% in phase I to 5.9%, 4%, and 0% in the three following phases. Hospital stay was 7.4, 6.1, 7.2, and 3.1 days for the consecutive phases. The restenosis rate for the combined four phases was 13% (15% in phase I, 20% in phase II, 11% in phase III, and 6% in phase IV). The overall rate of reintervention for the four phases was 8.9%. At 6 months, 84%, 75%, 94%, and 92% of the patients of phases I to IV, respectively, were event free. For the four phases, the event-free rate was 86%, which compares favorably with the rate observed in the Benestent-I study (80%; relative risk, 0.68 [0.45 to 1.04]). CONCLUSIONS: The implantation of stents coated with polyamine and end-point-attached heparin in stable patients with one significant de novo coronary lesion is well tolerated, is associated with no (sub)acute stent thrombosis, and results in a favorable event-free survival after 6 months.

Aspirin↗
PubMed1996

A randomized comparison of combined ticlopidine and aspirin therapy versus aspirin therapy alone after successful intravascular ultrasound-guided stent implantation.

BACKGROUND: Previous studies have shown that it is feasible to withhold anticoagulation after a successful intracoronary stent procedure with a low incidence of stent thrombosis. The importance of specific antiplatelet agents when stenting is performed without anticoagulation is unknown. METHODS AND RESULTS: After successful intravascular ultrasound-guided stenting, 226 patients were randomly assigned to receive either aspirin therapy alone (n = 103) or a combination of ticlopidine and short-term aspirin therapy (n = 123). Primary angiographic and clinical end points were stent thrombosis, death, myocardial infarction, the need for postprocedure coronary artery bypass surgery or repeated angioplasty, and significant medication side effects requiring termination of the medication within the first month of a successful procedure. At 1 month, the rate of stent thrombosis was 2.9% in the aspirin only group and 0.8% in the ticlopidine-aspirin group (P = .2). Cumulative major clinical events after successful stenting occurred in 3.9% of the patients in the aspirin group and in 0.8% in the ticlopidine-aspirin group (P = .1). There were no medication side effects in the aspirin group; in the combined ticlopidine-aspirin group, medication side effects occurred in 3 patients (P = .2). CONCLUSIONS: At 1 month, there was no difference in the incidence of stent thrombosis or other clinical end points between the two poststent antiplatelet regimens. However, the relatively small size of the study and the low incidence of thrombosis events may have contributed to the failure to detect differences in angiographic and clinical end points between the two groups.

Aged↗