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Biomedical subjects

R Pini

Publications and source records attributed to R Pini.

At least 55 records · Page 3Linked to original sources
PubMed1989

Laser dentistry: a new application of excimer laser in root canal therapy.

We report the first study of the application of excimer lasers in dentistry for the treatment of dental root canals. High-energy ultraviolet (UV) radiation emitted by an XeCl excimer laser (308 nm) and delivered through suitable optical fibers can be used to remove residual organic tissue from the canals. To this aim, UV ablation thresholds of dental tissues have been measured, showing a preferential etching of infiltrated dentin in respect to healthy dentin, at laser fluences of 0.5-1.5 J/cm2. This technique has been tested on extracted tooth samples, simulating a clinical procedure. Fibers of decreasing core diameters have been used to treat different sections of the root canal down to its apical portion, resulting in an effective, easy, and fast cleaning action. Possible advantages of excimer laser clinical applications in respect to usual procedures are also discussed.

Fiber Optic Technology↗
PubMed1989

Laser dentistry: root canal diagnostic technique based on ultraviolet-induced fluorescence spectroscopy.

A diagnostic technique to detect residual tissues at different levels of the root canal during an endodontic treatment is presented. The diagnostic system is based on ultraviolet-induced fluorescence spectroscopy and uses suitable optical fibers for local delivery of excitation light and to collect back fluorescence spectra. Spectra of root canal tissues have been obtained from split teeth by labeling with a fluorescent solution. Residual tissue can be discriminated in respect to healthy dentin because of their different spectral responses: the spectral shape of the first response shows a clear peak at 530 nm because of a selective absorption of the fluorescent dye, whereas for the second response, the spectral curve monotonically increases toward ultraviolet wave-lengths with no particular structure. This technique has been tested on unsplit teeth simulating operative conditions. A compact spectroscopic system has been devised that can be easily integrated in an excimer laser system to perform residual tissue detection during laser cleaning of the canals.

Fiber Optic Technology↗
PubMed1989

Relationship of atrial natriuretic factor to left ventricular volume and mass.

Although atrial natriuretic factor is primarily of atrial origin, recent observations indicate that the hormone is also synthesized by hypertrophied left ventricular myocardium. To assess the separate influences of left ventricular and left atrial dilatation and left ventricular hypertrophy on human atrial natriuretic factor levels, left atrial dimension and volume and left ventricular dimension and mass were compared in 49 normal subjects, in 33 patients with chronic aortic regurgitation, and in 15 patients with chronic mitral regurgitation. When compared with normal subjects, patients with chronic aortic and mitral regurgitation had similarly dilated and hypertrophied left ventricles (p less than 0.0005), while only mitral regurgitation patients had significantly enlarged (p less than 0.0005) mean left atrial dimension and volume. Likewise, plasma atrial natriuretic factor was elevated among patients with mitral regurgitation (60.3 +/- 47.0 fmol/ml) but was normal in patients with aortic regurgitation (19.0 +/- 11.0 fmol/ml versus 12.4 +/- 5.2 fmol/ml in normals; both p less than 0.0005 versus mitral regurgitation). Among all 97 subjects, atrial natriuretic factor levels correlated more closely with left atrial dimension and volume (r = 0.62 and 0.64, p less than 0.0005) than with left ventricular dimension (r = 0.44, p less than 0.0005) or mass (r = 0.40, p less than 0.0005). In addition, multivariate analysis indicated that left atrial volume bore a stronger independent relationship to plasma atrial natriuretic factor levels than either age or left ventricular variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Insufficiency↗
PubMed1989

Mitral valve dimensions and motion in Marfan patients with and without mitral valve prolapse. Comparison to primary mitral valve prolapse and normal subjects.

To determine mitral valve and extravalvular findings associated with mitral valve prolapse (MVP) in patients with the Marfan syndrome, we compared mitral leaflet and anular dimensions and motion by computerized two-dimensional echocardiography in 53 Marfan patients (28 with M-mode echocardiographic MVP) to those in 48 adults with primary MVP and in 35 normal subjects. Mitral leaflet billowing occurred in 28 of 28 Marfan patients with M-mode MVP versus 24 of 48 with primary MVP (p less than 0.00005), 0 of 25 Marfan patients without M-mode MVP, and 0 of 35 normal subjects (both, p less than 0.0001). Billowing occurred on the first systolic frame in 8 of 28 Marfan-MVP patients, in whom posterior leaflet chordae arose abnormally from the posterior ventricular wall, and in no other subjects. These patients had large mitral valves and normal anular dynamics, whereas the remaining 20 Marfan-MVP patients had increased systolic anular expansion. Marfan-MVP patients were younger than those without MVP (29 +/- 12 vs. 38 +/- 15 years, p less than 0.02) and had lower body mass index (19.8 +/- 2.7 vs. 23.9 +/- 2.9 kg/m2, p less than 0.00005) and systolic blood pressure (120 +/- 20 vs. 133 +/- 20 mm Hg, p less than 0.05), similar to differences between primary MVP and normal subjects in body mass index (21.5 +/- 3.0 vs. 23.9 +/- 4.8 kg/m2, p less than 0.01) and systolic pressure (118 +/- 14 vs. 125 +/- 18 mm Hg, p less than 0.05). Marfan patients with and without MVP had similar arm span, arm span to height ratio, upper to lower segment ratio, and prevalence of ectopia lentis and thoracic bony abnormalities, but arachnodactyly was more frequent in those with MVP (82% and 48%, respectively; p less than 0.02). We conclude that 1) leaflet billowing occurs more uniformly in Marfan patients with MVP than in primary MVP, 2) MVP in Marfan patients may be due to either valve enlargement with distinctively abnormal chordal architecture or abnormal mitral anular distensibility, 3) Marfan patients with MVP have low body weight and systolic blood pressure, similar to primary MVP, and 4) Marfan patients with MVP more commonly have arachnodactyly but otherwise have similar skeletal and anthropometric characteristics to other Marfan patients.

Echocardiography↗
PubMed1988

Comparison of mitral valve dimensions and motion in mitral valve prolapse with severe mitral regurgitation to uncomplicated mitral valve prolapse and to mitral regurgitation without mitral valve prolapse.

To determine the mitral valve abnormalities associated with hemodynamically important mitral regurgitation (MR) among patients with mitral valve prolapse (MVP), computerized 2-dimensional echocardiographic measurements of mitral leaflet and anular dimensions and motion in 26 patients with MVP and MR were compared to those in 48 subjects with uncomplicated MVP, 16 patients with MR due to etiologies other than MVP (rheumatic in 8) and 35 normal adults. Compared to both uncomplicated MVP and normal subjects, patients with MVP plus MR were older (p less than 0.05), had strikingly large mitral leaflets and anulus (p less than 0.0005) and were more likely to have systolic billowing of mitral leaflets in the parasternal long-axis view (24 of 26 [92%] vs 24 of 48 subjects with uncomplicated MVP [50%], p less than 0.001). Overlap in anular and posterior leaflet dimensions in normal and uncomplicated MVP subjects occurred in the 20 MVP plus MR patients who continue to be followed medically but not in the 6 MVP plus MR patients who underwent mitral valve surgery during 22 +/- 14 months follow-up. Patients with MR due to rheumatic or other non-MVP etiologies had enlargement of mitral leaflets and anulus virtually identical to that in MVP plus MR patients. In conclusion, patients with severe MR due to MVP are older, have striking mitral valve enlargement and more frequently exhibit leaflet billowing compared with subjects with uncomplicated MVP. Similar mitral leaflet enlargement was found in patients with non-MVP etiologies of MR, suggesting that mitral anular and leaflet enlargement may play a more general role in the pathogenesis of MR than is currently appreciated.

Adult↗
PubMed1988

Mitral valve dimensions and motion and familial transmission of mitral valve prolapse with and without mitral leaflet billowing.

To test the hypothesis that mitral valve prolapse may be due either to billowing of mitral leaflets into the left atrium or to dynamic expansion of the mitral anulus, mitral leaflet and annular dimensions and motion were measured by computer-assisted two-dimensional echocardiography in 35 normal adults and 48 subjects with auscultatory and M-mode echocardiographic evidence of mitral prolapse. Among normal subjects, mitral leaflet and annular dimensions tended to be larger compared with body size or left ventricular size in women than in men. Mitral leaflet billowing was observed in 24 (50%) of 48 patients with mitral prolapse and 0 of 35 normal subjects (100% specificity). The 24 patients without leaflet billowing had greater systolic expansion of the mitral anulus (p less than 0.0001) than did normal adults or patients with leaflet billowing (41 +/- 14% versus 27 +/- 12% and 22 +/- 11%, respectively) and a significantly lower body mass index (p less than 0.005 versus normal group). The ratio of anterior plus posterior mitral leaflet length to end-systolic annular diameter was lower in patients with prolapse without leaflet billowing than in normal subjects (1.09 +/- 0.12 versus 1.19 +/- 0.15, respectively, p less than 0.01) or patients with leaflet billowing (1.21 +/- 0.17, p less than 0.05). Among 35 relatives with mitral prolapse in the families of 23 patients with prolapse, the pattern was the same as in the proband in 31 (89%) (p less than 0.000002).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Two-dimensional echocardiographic imaging: in vitro comparison of conventional and dynamically focused annular array transducers.

Quantitative two-dimensional echocardiography has been adversely affected by a tendency for underestimation of cross-sectional areas of cardiac chambers, a difficulty that might be ameliorated by recent advances in imaging technology. To determine if this were so, we measured echocardiographic cross-sectional areas of 25 formalin-fixed animal left ventricular (LV) sections in vitro using conventional 13 mm and 15 mm diameter fixed-focused single element transducers, and a 15 mm diameter dynamically focused annular array transducer at 3 different distances between myocardial slice and transducer (2 cm, 6 cm and 10 cm) and compared the 2-dimensional echocardiographic areas to the corresponding anatomic cross-sectional areas of the same hearts. LV total and cavity area were measured by computer assisted planimetry of videotaped echo images, performed blinded to the transducer used, and photographed anatomic slices; LV myocardial area was derived by subtraction. Comparison of two-dimensional echocardiographic total, myocardial, and cavity areas with corresponding anatomic measurements showed excellent correlation for each transducer at all depths (r = 0.97 to 0.98 for total area; r = 0.98 to 0.99 for cavity area; r = 0.93 to 0.97 for myocardial area). For total and myocardial cross-sectional areas, the slope of the relation between echographic and anatomic areas did not differ significantly from unity, but for LV cavity area this was achieved only by the dynamically focused transducer. In contrast, the conventional 13 mm transducer significantly underestimated larger LV cavity areas in both the near and middle fields (slopes = 0.90 and 0.91, respectively) and the 15 mm transducer yielded slopes from 0.86 to 0.91 in all fields.(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiography↗
PubMed1985

Hemodynamic and electrocardiographic effects of fructose-1,6-diphosphate in acute myocardial infarction.

Acute hemodynamic and electrocardiographic effects of fructose-1,6-diphosphate (FDP), an agent that is supposed to restore anaerobic glycolytic flux in the ischemic myocardium, were studied in 40 patients with acute myocardial infarction who were grouped into 4 subsets: subset 1, normal (15 mm Hg or less) pulmonary artery (PA) wedge pressure and normal (35 g-m/m2 or greater) left ventricular (LV) stroke work index; subset 2, elevated (more than 15 mm Hg) PA wedge pressure and normal LV stroke work index; subset 3, normal PA wedge pressure and reduced (less than 35 g-m/m2) LV stroke work index; subset 4, elevated PA wedge pressure and LV stroke work index moderately reduced to a range between 16 and 34 g-m/m2. Patients were randomized into an FDP (250 mg/kg body weight in isotonic saline solution intravenously in 20 minutes) and into a placebo group. Each subset contained 5 FDP- and 5 placebo-treated patients. After basal measurements, hemodynamic measurements were reassessed at 60, 90 and 120 minutes from the infusions, while a standard 12-lead electrocardiogram was recorded in the basal state and 120 minutes after infusion. Nonsignificant hemodynamic change was observed in the placebo subsets, and FDP failed to exert any effect in subsets 1, 2 and 3. A 24% (p less than 0.02) increase in cardiac index occurred 60 minutes after FDP in subset 4. LV stroke work index also increased, while PA wedge pressure remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Hemodynamic effects of digoxin in acute myocardial infarction in man: a randomized controlled trial.

Hemodynamic effects of digoxin in acute myocardial infarction (AMI) have been acknowledged to depend on the basal cardiocirculatory state. In the present study, the effects of digoxin in patients with AMI were evaluated in four hemodynamic subsets, based on the relationship between mean pulmonary capillary wedge pressure (PCWP, in mm Hg) and left ventricular stroke work index (LVSWI, in g-m/m2): subset 1: normal (less than or equal to 15 mm Hg) PCWP and normal (greater than or equal to 35 g-m/m2) LVSWI; subset 2: elevated (greater than 15 mm Hg) PCWP and normal LVSWI; subset 3: reduced (less than 35 g-m/m2) LVSWI and normal PCWP; and subset 4: elevated PCWP and LVSWI moderately reduced to a range between 16 and 34 g-m/m2. Forty patients were admitted to the study and were randomly assigned to one of two groups in each subset: control group (19 patients) and treated group (21 patients). Five patients were randomized into each of the subsets 2, 3, and 4 in both the control and treated groups, while in subset 1 there were four control and six digoxin-treated patients. Control patients were administered a placebo saline solution and digoxin-treated patients received 0.50 mg of the drug intravenously in 20 minutes. The effects of the placebo and of the drug were evaluated at 30, 60, and 90 minutes from the end of the infusion. Hemodynamic data did not vary in the control group, and digoxin did not exert any relevant effect in subsets 1 and 2. After drug infusion, cardiac index (Cl, in L/min/m2) significantly increased in subset 3 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Echocardiographic features of right ventricular infarction.

In a series of 75 consecutive patients with transmural acute myocardial infarction (AMI) a right-to-left ventricular filling pressure ratio equal to or greater than 0.65 (RVFP/LVFP greater than or equal to 0.65) was assumed to be indicative of associated right ventricular infarction (RVI). Out of 45 patients with inferoposterior myocardial infarction, 11 (24%) had such hemodynamic evidence of right ventricular infarction (group A). The remaining 34 patients with inferoposterior myocardial infarction (group B) and the 30 patients with anterior myocardial infarction did not. Time-motion and two-dimensional echocardiographic examinations were performed 7-10 days after admission in the 62 patients who survived. Right ventricular wall asynergy was found in six of eight group A patients. In three of these, right ventricular dilatation was also present. No patient in group B with inferior infarction or with anterior infarction showed abnormal right ventricular wall motion. While hemodynamic monitoring seems presently the most specific diagnostic method and it is of invaluable help in the choice of the best pharmacological therapy of right ventricular failure due to RVI, two-dimensional echocardiography is probably highly sensitive and specific for the diagnosis of RVI, by detecting RV wall motion and thickening abnormalities. Due to advantages, such as noninvasivity and repeatibility, two-dimensional echocardiography can be used in the selection of patients who deserve hemodynamic monitoring and in follow-up studies.

Adult↗
PubMed1984

Intra-aortic balloon pumping in the elderly: percutaneous versus surgical catheter insertion.

The feasibility and safety of percutaneous versus intra-aortic balloon pumping (IABP) in the elderly were evaluated in 45 patients who were over 65 years of age (range 65-79). All the patients required counterpulsation for complicated acute myocardial infarction. IABP insertion was attempted by the surgical technique in 22 patients, while the percutaneous approach was performed in 23. A consistent improvement in the incidence rate of successful insertion was attained with the use of the percutaneous technique as compared with the surgical one (91.3% v 59.1%, P is less than 0.05). Furthermore, no major complication was observed with the percutaneous catheter, while a 9.1% (2/22) incidence rate of serious complications was reported with the surgical technique. Thus, percutaneous IABP substantially decreased the unsuccessful insertions and the risk of severe complications in old patients, despite presumably severe aorto-iliac disease. No specifically age-related technical problem seems, therefore, to limit the applicability of intra-aortic counterpulsation to elderly patients, when percutaneous IABP is employed.

Aged↗
PubMed1983

Right ventricular infarction: clinical, hemodynamic, mono- and two-dimensional echocardiographic features.

In a series of 75 patients with transmural acute myocardial infarction, a right to left ventricular filling pressure ratio equal to or greater than 0.65 was assumed to be indicative of associated right ventricular infarction. Eleven (24%) out of 45 patients with infero-posterior myocardial infarction had such hemodynamic evidence of right ventricular infarction (Group A). The remaining 34 patients with infero-posterior myocardial infarction (Group B) and the 30 patients with anterior myocardial infarction did not. Two-dimentional echocardiographic examination performed 5 days after admission in the 62 patients who survived, showed right ventricular free wall asynergy in six out of eight Group A patients: in three of them right ventricular enlargement was present. No patient in Group B inferior infarction or with anterior myocardial infarction had abnormal right ventricular motion or dimensions.

Adult↗
PubMed1983

[A case of postinfarction spontaneous angina: physiopathological study of the therapeutic effectiveness of intra-aortic balloon pumping].

A 46-year-old patient showed spontaneous angina with anterior S-T segment depression 30 hours after an inferior acute myocardial infarction. Myocardial ischemia, which was resistant to drug therapy and induced acute left ventricular failure, was promptly reversed by intra-aortic balloon pumping (IABP). Coronary angiography demonstrated diffuse, severe atherosclerotic disease. Efficacy of IABP in this case of spontaneous angina might be ascribed to an increase of the coronary cross-sectional area in response to the increased intraluminal pressure ("passive vasomotion").

Angina Pectoris↗