Synthesis of Mannosyl and Oligomannosyl Threonine Building Blocks found on the Mycobacterium tuberculosis 45 kDa MPT 32 Glycoprotein

Mycobacterium tuberculosis secretes a 45 kDa glycoprotein (MPT 32) carrying mannosylated threonine residues. A general strategy was developed to couple peracetylated mannose, α -(1,2)-linked mannobiose or mannotriose to Fmoc-threonine-benzyl ester. Activation of mannosyl acetates or fluorides by borontrifluoride etherate gave the desired Fmoc-glycosyl amino acid building blocks in good yields. The synthesis leads to stable compounds and can easily be scaled up.

In-stent neointimal proliferation correlates with the amount of residual plaque burden outside the stent: an intravascular ultrasound study

BACKGROUND

The aim of this study was to evaluate the relationship between residual plaque burden after coronary stent implantation and the development of late in-stent neointimal proliferation.

METHODS AND RESULTS

Between January 1996 and May 1997, 50 patients underwent intravascular ultrasound (IVUS) interrogation at 6+/-1.2 months after coronary stent implantation in native coronary arteries. IVUS images were acquired with a motorized pullback, and cross-sectional measurements were performed within the stents at 1-mm intervals. The following measurements were obtained: (1) lumen area (LA), (2) stent area (SA), (3) area delimited by the external elastic membrane (EEMA), (4) percent neointimal area calculated as (SA-LA/SA)x100, and (5) percent residual plaque area calculated as (EEMA-SA)/EEMAx100. Volume measurements within the stented segments were calculated by applying Simpson's rule. In the pooled data analysis of 876 cross sections, linear regression showed a significant positive correlation between percent residual plaque area and percent neointimal area (r=0.50, y= 45.03+0.29x, P<0.01). There was significant incremental increase in mean percent neointimal area for stepwise increase in percent residual plaque area. Mean percent neointimal area was 16.3+/-10.3% for lesions with a percent residual plaque area of <50% and 27.7+/-11% for lesions with a percent residual plaque area of >/=50% (P<0.001). The volumetric analysis showed that the percent residual plaque volume was significantly greater in restenotic lesions compared with nonrestenotic lesions (58.7+/-4.3% versus 51.4+/-5.7%, respectively; P<0.01).

CONCLUSIONS

Late in-stent neointimal proliferation has a direct correlation with the amount of residual plaque burden after coronary stent implantation, supporting the hypothesis that plaque removal before stent implantation may reduce restenosis.

[The clinical, angiographic and procedural predictors of thrombosis and restenosis in Micro stent II (AVE) coronary stents]

The aim of the study was to assess the incidence and the predictors of thrombosis and restenosis in Micro stent II AVE. In a sample of 197 stents successfully implanted in 181 consecutive patients, the incidence of thrombosis was 4.1%. The multivariate analysis showed the minimum lumen diameter post-stenting to be the only independent predictor of overall thrombosis. In fact, we found that the risk of thrombosis increases as the minimal lumen diameter decreases. Angiographic follow-up was available in 74% of the stents at 6.8 +/- 4.1 months and stent restenosis occurred in 26.2% of cases. Independent predictors of restenosis (multivariate linear discriminant analysis) were: 1) nominal stent diameter (the risk of restenosis decreases as the stent diameter increases); 2) the ratio between the diameter of the balloon carrying the stent measured at the maximum pressure/nominal stent diameter (the risk increases as the ratio decreases); 3) stented vessel (the risk increases in the following order: right coronary < circumflex < left anterior descending); 4) the American Heart Association classification of lesion morphology (the risk increases in the order A < B < C); 5) a lower risk was found in the absence of diabetes mellitus.

Incidence of compensatory enlargement and paradoxical shrinkage of coronary arteries in presence of atherosclerotic lesions: an intracoronary ultrasound study based on multiple cross-section analysis per artery

BACKGROUND

The aim of the study was to evaluate with intravascular ultrasound (IVUS) the incidence of compensatory enlargement and paradoxical shrinkage in 50 de novo coronary lesions, using two different approaches: 1) a single cross-section analysis and 2) a multiple cross-section analysis per artery. A 3-D IVUS system based on contour detection of lumen and plaque was applied (image acquisition speed: 0.5 mm/s, digitization rate: 5 images/s). In each cross section, we determined: 1) the lumen area (LA), 2) the external elastic membrane area (EEMA), 3) the plaque+media complex (p+m), 4) the relative EEMA = cross section EEMA/reference EEMA, 5) the relative p+m area = cross-section p+m area/reference p+m area, 6) the lumen area stenosis: 1-(cross-section LA/reference LA). In the single cross-section analysis, compensatory vessel enlargement was defined as narrowest EEMA > reference EEMA, and paradoxical vessel constriction as narrowest EEMA < reference EEMA. In the multiple cross-section analysis, compensatory vessel enlargement was defined as the presence of a significant positive correlation between relative EEMA and relative p+m area and paradoxical vessel constriction as a significant negative correlation between relative EEMA and lumen area stenosis.

RESULTS

In the single cross-section analysis, compensatory vessel enlargement and paradoxical constriction occurred in 58 and 42% of cases respectively. The multiple cross-section per artery analysis showed compensatory vessel enlargement in 80% of cases and paradoxical constriction in 36% of cases and revealed the combination of compensatory enlargement with paradoxical constriction in 22% of the analyzed segments.

CONCLUSIONS

Compensatory enlargement of coronary arteries was underestimated by the single cross-section analysis and was observed in 80% of cases when a multiple cross-section per artery analysis was applied. Paradoxical shrinkage was less common and often occurred in combination with compensatory enlargement within the same analyzed segment.

Three-dimensional reconstruction techniques applied to intracoronary images

In recent years, systems for the three-dimensional (3-D) reconstruction of intravascular ultrasound (IVUS) images have been developed. As a major advantage over conventional two-dimensional IVUS, 3-D IVUS offers longitudinal views of the reconstructed segments and provide more comprehensive insight into the spatial distribution of vascular structures. The present article is an overview of current 3-D reconstruction techniques. In particular, we discuss the sequence of basic steps required to obtain a 3-D reconstruction: IVUS image acquisition, digitization, segmentation and reconstruction. We also illustrate the different systems of 3-D reconstruction that are currently available. Some of them can be used on-line during surgical procedures, while others are more suited for off-line applications and are useful research tools.

Coexistence of vessel enlargement and paradoxical constriction in a diseased left anterior descending artery: an in vivo assessment using a new system for quantitative analysis of intracoronary ultrasound

Previous studies based on conventional two-dimensional intravascular ultrasound revealed that coronary arteries can undergo either vessel enlargement and paradoxical constriction in response to plaque growth. We report a case in which the occurrence of vessel enlargement and paradoxical constriction was documented in the same coronary artery (left anterior descending). A multiple cross-section analysis was performed, using a novel 3-D system of reconstruction of IVUS images, which provides a large number of cross-sections within the reconstructed segments.

Restrictive cardiomyopathy due to desmin accumulation in a family with evidence of autosomal dominant inheritance

OBJECTIVE

A familial case of restrictive cardiomyopathy due to desmin accumulation characterized by severe disturbances of cardiac conduction is described.

BACKGROUND

Desmin is an intermediate filament normally present in the myocardium, particularly in the Purkinje fibres, in the skeletal and in the smooth muscle.

METHODS

Resting electrocardiogram, 2-dimensional and Doppler echocardiogram, cardiac catheterization, electrophysiological study have been performed in all siblings. Informed consent for endomyocardial biopsy was obtained only in one patient.

RESULTS

The mother showed bilateral pes cavus and complained of episodes of vertigo at the age of 36 years. At that time she was submitted to electrophysiological study and to permanent pacing. After 15 years of good health conditions, she developed heart failure and underwent cardiac transplantation. A 21 year old son had a syncope; his ECG was similar to that of his mother; a permanent pacemaker was implanted and a diagnosis of restrictive cardiomyopathy with desmin accumulation was confirmed at histopathology study. Afterwards, another 24 year old sib had a syncope with head trauma: ECG showed right atrial enlargement, left bundle branch block. After electrophysiological study, he started antiarrhythmic therapy. This patient showed bilateral pes cavus.

CONCLUSIONS

The early manifestation of desmin accumulation may be intraventricular conduction disorders that can be often controlled by pacemaker implantation. Clinical symptoms of heart failure may be absent for a long period of time. Pedigree analysis is most consistent of autosomal dominant inheritance.

Value of low-dose echodobutamine in the diagnosis of patency of the infarct related coronary artery

The resumption of contractility of asynergic segments in survivors after acute myocardial infarction (AMI) may be detected in viable myocardial areas. We have correlated the detection of viable myocardium, assessed with low dose dobutamine testing, with coronary angiography and clinical outcome in 66 consecutive survivors of AMI using the echocardiographic evidence of left ventricular wall motion abnormalities. The test enabled the identification of two groups: group A, comprising 32 patients (pts) demonstrating wall motion recovery at dobutamine infusion and group B, comprising 34 pts without wall motion recovery. The mean basal asynergy score index was 5.8 +/- 4.2 in group A and 6.0 +/- 4.2 in group B (p = ns). With dobutamine testing the score decreased to 2.8 +/- 3.6 in group A (p < 0.001 with respect to basal value), while it did not change significantly in group B. Left ventricular end diastolic volume (ml) was similar in the two groups (114 +/- 35 vs 107 +/- 79, p = NS). The infarct related artery (IRA) patency rate was 87.5% in group A, vs 26.5% in group B (p < 0.001). After a mean follow-up of 11 +/- 5 months, group A pts had basal asynergy score improvement (2.6 +/- 3.1, p < 0.001) and mild left ventricular end diastolic volume (ml) reduction, (108 +/- 32, p = NS), while group B pts had left ventricle end diastolic volume enlargement (130 +/- 38, p < 0.05), without score asynergy modification. Moreover all pts who experienced heart failure at follow-up were in group B.(ABSTRACT TRUNCATED AT 250 WORDS)

[The usefulness of the echo-dipyridamole test in the early period after an uncomplicated acute myocardial infarct]

OBJECTIVES

The aim of this study was to examine the ability of Dipyridamole Echocardiography Test (DET)--performed early after an acute myocardial infarction (AMI)--to assess: a) the presence of induced ischemia and its relation with coronary artery stenoses; b) the presence of myocardial viability and the comparison with late wall motion; c) the appearance of cardiac events during hospitalization and in the following period.

METHODS

Ninety-five patients with AMI, subjected to thrombolytic therapy and without complications, underwent a DET on the 4th-5th day. All had a coronary angiography on the 8th-10th day; stenoses were deemed significative when > or = 70%. DET was carried out after drug discontinuance and following standard protocol; parietal kinesis was analyzed according to a 14 segment model. The myocardium was deemed viable when an improvement of a basal dyskinesis was noted; ischemia was considered when a new asynergy appeared or a basal dyskinesis worsened or enlarged; a wall motion score index (WMSI) was calculated. All 95 pts. had a clinical follow-up at 12 +/- 6 months (3-18); 62 pts. had a late echocardiographic examination at 6 +/- 3 months (3-15).

RESULTS

Induced ischemia appeared in 59/95 pts. (62%): in 6/14 pts. (42%) without significative stenoses, in 29/49 pts. (59%) with a single vessel disease, and in 24/32 pts. (75%) with multivessel disease. In identifying multivessel disease, DET sensibility (SE) was 75% and specificity (SP) was 95-97%. In single or no vessel disease WMSI changed from 1.42 to 1.49 (p < 0.0001); in multivessel disease WMSI changed from 1.52 to 1.69 (p < 0.0001). As regards the assessment of diseased vessel(s), DET showed little accuracy when dyskinesis appeared in the basal segments of the inferior and lateral wall or in the mid-apical segments of the anterior and lateral wall; DET properly identified the culprit vessel when dyskinesis appeared in the remaining segments. Myocardial viability was noted in 26% of dyskinetic segments. In single or no vessel disease WMSI changed from 1.41 (basal--> B) to 1.35 (viability phase--> V) and was found 1.31 at the late echocardiography (L): p < 0.0001 between B and V, and between B and L. In multivessel disease WMSI changed from 1.5 (B) to 1.47 (V) and to 1.5 (L): p < 0.05 between B and V, NS between B and L. In comparison with late echocardiography, DET SE was 70%, SP 99%, positive predictive value (PPV) 97%, negative predictive value (NPV) 86%. As regards the prognostic value about cardiac events, DET SE was 80% and NPV was 78%; about only major cardiac events, the respective values are 91% and 97%.

CONCLUSIONS

DET performed early after an AMI allows a better prognostic assessment, as it provides information about: a) the place and the severity of coronary artery stenoses; b) the presence and the extension of induced ischemia and of myocardial viability; c) the risk of subsequent cardiac events.

Dipyridamole echocardiography evaluation of acute inferior myocardial infarction with concomitant anterior ST segment depression

The significance of anterior ST segment depression in inferior acute myocardial infarction (AMI) remains controversial. The aim of this study was to relate precordial ST segment depression to the topography of residual myocardial ischaemia, with myocardial mapping of the asynergic area and coronary anatomy. Twenty-five patients with first inferior AMI (15 patients with anterior ST segment depression: group A and 10 patients without anterior ST segment shift: group B), all underwent: (1) electrocardiographic evaluation on admission to the Coronary Care Unit and at 24 h intervals thereafter; (2) 2D-echocardiographic study within 3 h of CCU admission; (3) dipyridamole echocardiographic test (DET) (doses of dipyridamole up to 0.84 mg.kg-1 i.v. over 10 min) 4 days after AMI; (4) coronary arteriography within 14 days from AMI. To assess regional left ventricular wall motion, a 16 segment model was used and a wall motion score index (WMSI) was derived. The results of DET were correlated to the anatomy of the infarct-related vessel. Compared to group B, group A patients showed a significantly greater maximal ST segment elevation in inferior limb leads (lead III: 3.9 +/- 1.9 mm vs 2.2 +/- 1.1 mm, P < 0.05; aVF: 3.5 +/- 1.3 mm vs 1.7 +/- 0.8 mm, P < 0.001). Group A patients showed greater WMSI (1.35 +/- 0.22 vs 1.17 +/- 0.12, P < 0.05), with more frequent postero-lateral wall involvement (72% vs 20%, P < 0.05). No patient of either group showed asynergy of the anterior, anterolateral or anteroseptal segments. No differences in the distribution of coronary artery disease were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Single coronary artery, anomalous origin of the right coronary artery from the left anterior descending artery

We present a patient with an abnormal origin of the right coronary artery from the left anterior descending artery. The patient had chest pain probably related to myocardial ischaemia. This anomaly is very rare and has previously been reported in only three cases. The abnormal vessel travelled rightwards and remained anterior to the main pulmonary artery, it was free of significant stenosis. The mechanism of anterior myocardial ischaemia remains unexplained.

The response of the coronary collateral circulation to acute administration of nifedipine: an angiographic and ergometric study

To evaluate the role of collaterals in patients with effort angina we retrospectively compared the coronary cineangiograms of 14 subjects ("responders") who improved their exercise tolerance after acute nifedipine therapy with 14 subjects ("non-responders") with the same symptomatology who did not respond to the same treatment. The status of collaterals was graded with a score from a minimum of 0 to a maximum of 5. The responders showed a greater score than the non-responders (3 +/- 1 vs. 1 +/- 1, P less than 0.001), whereas there was no difference in the number of stenosed vessels between the two groups (1.8 +/- 0.9 vs. 2 +/- 0.8). Thus, in patients with effort angina and critical coronary stenosis, the presence of an efficient coronary collateral circulation can favour the increase in coronary flow reserve after vasodilator therapy. Our results suggest that the grading of collaterals may add useful information to the simple classification of one-, two- or three-vessel coronary artery disease.

Ultrastructure of cell-mediated immunity. I. Comparison between E and EA rosettes

The ultrastructural comparison between E and EA rosettes showed that, in the former, the rosetting lymphocytes are mostly round in shape and their interaction with sheep erythrocytes only consists of limited areas of membrane contact, in the latter, rosetting lymphocytes are mostly in the shape of uropods and surrounding ox red cells show pseudopods protruding towards the lymphocyte and coming into contact with it.