Biomedical subjects
Publications and source records attributed to P Colonna.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The emphasis of this review is on starch structure and its biosynthesis. Improvements in understanding have been brought about during the last decade through the development of new physicochemical and biological techniques, leading to real scientific progress. All this literature needs to be kept inside the general literature about biopolymers, despite some confusing results or discrepancies arising from the biological variability of starch. However, a coherent picture of starch over all the different structural levels can be presented, in order to obtain some generalizations about its structure. In this review we will focus first on our present understanding of the structures of amylose and amylopectin and their organization within the granule, and we will then give insights on the biosynthetic mechanisms explaining the biogenesis of starch in plants.
BACKGROUND: The treatment of Hodgkin's disease (HD) at advanced stages relies mainly upon multi-agent chemotherapies (CT), while the role of radiation therapy has not been definitely identified. The aim of this report is to analyze the 10-year results of a prospective study including 133 patients with HD clinical stages (CS) IIIA to IVB treated by three monthly courses of ABVD (adriamycin, bleomycin, vinblastin, and dacarbazine) followed by high-dose subtotal or total lymphoid irradiation [(S)TLI]. PATIENTS AND METHODS: From 1 October 1981 to 30 September 1988, 133 adult patients with HD CS IIIA (45), IIIB (33), IVA (seven) and IVB (48) were entered in the non-randomized multicentric prospective trial POF81/34. The number of involved nodal areas (NINA), and the number of visceral sites (NVIS) involved were registered in all patients; patients with bulky mediastinal tumor (BuMT) (mediastinal mass ratio > or = 0.45) were also identified. All patients received three monthly cycles of ABVD. Patients in complete remission (CR) or partial remission (PR) after completion of CT received a (S)TLI including the spleen (involved sites 40 Gy, non-involved 30 Gy); initially involved lung(s) and liver received 18 and 20 Gy, respectively; and patients not in CR or PR after CT or RT received salvage treatments. Univariate and multivariate analyses were performed to identify the factors contributing significantly to the prognosis; initial characteristics, as well as status after the three cycles of CT, were entered in the model. RESULTS: Of the 133 patients, 74 (55.6%) entered in CR after CT and 116 (87.2%) after completion of radiation therapy. Ten-year freedom from progression (FFP), freedom from tumor mortality (FFTM) and survival rates were 70.4%, 78.9% and 70.6%, respectively. According to univariate analysis the NVIS (< or = one vs. > or = two) was the only initial factor simultaneously influencing 10-year FFP (73.9% vs. 38.2%) FFTM (82.5 vs. 34.1%) and survival (73.5% vs. 17.3%) rates; on the other hand, the NINA (< or = four vs. > or = five) influenced FFP (81.4% vs. 60.7%) and FFTM rates (87.3% vs. 71.4%) while symptoms (A vs. B) influenced FFP (80.7% vs. 63.3%) and survival (82.8% vs, 61.2%) rates. Finally, age (< 40 vs. > or = 40) influenced survival rate only (79.2% vs. 50%). According to multivariate analysis, NVIS and NINA had an independent impact on FFP and FFTM, while survival was modified by the NVIS and age. The post-CT status (CR vs. no CR) had a major impact on FFP (85.3% vs. 64.9%) FFTM (92.1% vs. 63.3%) as well as on survival (78.6% vs. 54.7%) rates in both univariate and multivariate analyses. Complications of therapy were mainly due to RT: 11 patients acquired second malignancies, six developed lung fibrosis or severe pulmonary infections, three developed intestinal obstructions and six developed angina pectoris or carotid stenosis. CONCLUSIONS: Tumor burden (identified by the number of involved nodal areas and the number of visceral sites) and the response to initial CT were the two independent factors influencing the outcome of this group of 133 patients with HD, CSIII and IV treated by three cycles of ABVD followed by high-dose [(S)TLI].
The aims of this study were to measure the amount of starch from partially resistant starches (retrograded and complexed high-amylose cornstarches) escaping small-intestinal digestion in healthy humans by use of an intubation method and to compare these data with data obtained by indirect in vitro methods. Experiments were carried out in vivo in 6 healthy humans by using ileal intubation and stool analysis and in vitro by using 3 different methods for analyzing resistant starch. In intubated subjects, 51 +/- 2% of the retrograded and 21 +/- 2% of the complexed starch was delivered to the ileum and was fermented almost completely in the colon. In vitro estimates of the absorption of resistant starch were much lower. We conclude that technologically modified starches may substantially increase the amount of carbohydrate available for colonic fermentation in humans, but that in vitro measurements of resistant starch are inaccurate for predicting malabsorption in healthy humans.
BACKGROUND: Several approaches have been used for noninvasive estimation of right atrial pressure (RAP), but, no currently available method has gained any definite validation. The purpose of this study was to evaluate the accuracy of two-dimensional and Doppler echocardiography in estimating mean RAP in patients with cardiac disease. METHODS: We examined the relation of mean RAP to right atrial size and function, size and respiratory changes of inferior vena cava and Doppler parameters of tricuspid and hepatic vein flow in 114 consecutive patients (77 men, 37 women; mean age 57 +/- 12 years) with various cardiac diseases undergoing cardiac catheterization. Echocardiographic studies were performed within 24 hours before catheterization (mean interval 6 +/- 3 hours). Patients were assigned to 3 groups according to the values of mean RAP (group 1, < or = 8 mmHg; group 2, between 9 and 12 mmHg; group 3, > 12 mmHg). RESULTS: Mean RAP ranged from 3 to 20 mmHg (mean 9.1 +/- 4.3 mmHg). It correlated most strongly with the collapsibility index of inferior vena cava (IVCCI) (r = -0.76), minimal inspiratory diameter of inferior vena cava (r = 0.72) and deceleration time of early tricuspid flow (DT) (r = -0.61). Discriminant analysis demonstrated that IVCCI and DT were major determinants of mean RAP with 81.6% of cases correctly assigned to study groups: 96% of patients of group 1 and 87% of patients of group 3 were identified, whereas the accuracy in identifying the patients of group 2 was lower (46%). An IVCCI > 45% was the best cutoff point in predicting a mean RAP < or = 8 mmHg; an IVCCI < 35% and a DT < 150 msec were the best cutoff points in predicting a mean RAP > or = 15 mmHg. The best multivariate equation predicting mean RAP was: mean RAP = 23.3 - 0.2 IVCCI -0.026 DT (r = 0.80, R2 = 0.64). This equation was 81% sensitive and 84% specific in detecting a mean RAP < or = 8 mmHg and 74% sensitive and 97% specific in detecting a mean RAP > 12 mmHg. CONCLUSIONS: Mean RAP can be estimated noninvasively by two-dimensional and Doppler echocardiography. The combined analysis of IVCCI and DT provides an accurate prediction on mean RAP < or = 8 mmHg and > 12 mmHg, whereas the prediction of intermediate values is less accurate.
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A functionally patent foramen ovale can create a relevant right-to-left shunt during massive pulmonary embolism. This associated feature, although maintaining adequate cardiac output, may explain both the paradoxic embolism and the uneffectiveness of peripherally administered drugs. This case demonstrates the potential of transesophageal echocardiography in monitoring the hemodynamic findings of such patients and, consequently, the effectiveness of thrombolytic treatment.
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AIMS: To evaluate the effects of acute, atrial pacing-induced, reversible myocardial ischaemia on myocardial thickening and integrated backscatter cyclic variations in patients with or without coronary artery disease. METHODS AND RESULTS: Thirty-six patients with suspected coronary artery disease underwent transoesophageal echocardiography with simultaneous atrial pacing, and coronary angiography. In myocardial segments not related to a significantly narrowed coronary artery, both from patients with and without coronary artery disease, thickening and integrated backscatter cyclic variations were not reduced at peak pacing. In segments related to a significantly narrowed coronary artery, thickening decreased at peak pacing, was still reduced at pacing interruption and recovered at 2 min, while backscatter cyclic variations, blunted at peak pacing, immediately recovered after pacing interruption. CONCLUSION: During stress-induced myocardial ischaemia, backscatter cyclic variations are blunted and thickening reduced. Returning to baseline, pre-atrial pacing values occur more rapidly in backscatter cyclic variations than when thickening takes place. Evaluation of stress-induced alterations in backscatter cyclic variations may aid in the identification of ischaemia-induced regional left ventricular functional impairment and, hence, in coronary artery disease diagnosis.
AIMS: The study was set up to evaluate the functional role of post-infarct preserved microvascular integrity. Low dose dobutamine echocardiography and myocardial contrast echocardiography were used to study patients before hospital discharge who had suffered a recent myocardial infarction and had a patent infarct-related artery (TIMI flow grade 3). METHOD: In the dysfunctioning infarct area, the wall motion score index was calculated at baseline, during the dobutamine infusion and at the 3 month follow-up echocardiogram; contrast echocardiography was performed at the time of coronary angiography, before hospital discharge. RESULTS: In patients with more than 50% of the dysfunctioning infarct area opacified at contrast echocardiography (group A), regional wall motion score index decreased, compared to baseline, during the dobutamine infusion (1.97 +/- 0.78 vs 2.5 +/- 0.35 at baseline; P < 0.001) and at follow-up echocardiography (1.83 +/- 0.63 vs 2.5 +/- 0.35 at baseline; P < 0.001). In patients with less extensive microvascular integrity as revealed by contrast echocardiography (group B), regional wall motion score index did not decrease from baseline during either the dobutamine infusion (2.73 +/- 0.21 vs 2.81 +/- 0.20 at baseline; P = ns), or at follow-up (2.81 +/- 0.20 vs 2.81 +/- 0.20 at baseline; P = ns). CONCLUSION: In patients with post-infarct dysfunctioning myocardium but a patent infarct-related artery, microvascular integrity, as assessed by myocardial contrast echocardiography, is an indicator of myocardial viability in terms of preserved contractile reserve, as demonstrated by dobutamine infusion and functional recovery at follow-up.
A case of sepsis in a pediatric patient due to the newly described Citrobacter species C. farmeri is described. Factors predisposing this child to infection included short-bowel syndrome requiring total parenteral nutrition.
The diagnostic value of echo-pacing has been previously report. Recently, monoplanar transesophageal echocardiography (TEE) has been used to improve the reliability of this stress procedure. Therefore, in 40 consecutive patients undergoing coronary angiography for suspected coronary artery disease (CAD) we tested the accuracy of atrial pacing (TAP) during multiplane TEE as a stress procedure. TAP was performed during TEE using a circular, adhesive electrode installed at the tip of the echoscope and connected to the pulse generator. In all patients TAP was firstly attempted by positioning the TEE probe in the esophagus and, if not successful, in the stomach. Left ventricular wall motion was monitored by means of 4, 2 chamber and long axis views from the esophagus and short axis scan from the stomach, in baseline conditions, at peak pacing and immediately after maximal heart rate. The test was considered positive if wall motion abnormalities developed during TAP. Stable capture of the atrium was obtained in 28 patients from the esophagus and in 6 patients from the stomach. Thus, TEE-TAP was performed in 34/40 patients (feasibility 85%). Wall motion abnormalities were detected during TAP in 20/24 with and in 2/10 patients without CAD. Thus, sensitivity and specificity of TEE-TAP were 83% and 80% respectively. The sensitivity of the test in single and multivessel disease resulted 72% and 92%. The 12 lead electrocardiogram during TAP showed a sensitivity of 66% and a specificity of 40% (p < 0.01 vs TEE-TAP). In conclusion, TEE-TAP is a new approach for CAD evaluation providing a complete and accurate imaging of left ventricular wall motion.
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