Texture analysis of iodine maps and conventional images for k-nearest neighbor classification of benign and metastatic lung nodules

BACKGROUND

The purpose of this study was to analyze if the use of texture analysis on spectral detector CT (SDCT)-derived iodine maps (IM) in addition to conventional images (CI) improves lung nodule differentiation, when being applied to a k-nearest neighbor (KNN) classifier.

METHODS

183 cancer patients who underwent contrast-enhanced, venous phase SDCT of the chest were included: 85 patients with 146 benign lung nodules (BLN) confirmed by either prior/follow-up CT or histopathology and 98 patients with 425 lung metastases (LM) verified by histopathology, 18F-FDG-PET-CT or unequivocal change during treatment. Semi-automatic 3D segmentation of BLN/LM was performed, and volumetric HU attenuation and iodine concentration were acquired. For conventional images and iodine maps, average, standard deviation, entropy, kurtosis, mean of the positive pixels (MPP), skewness, uniformity and uniformity of the positive pixels (UPP) within the volumes of interests were calculated. All acquired parameters were transferred to a KNN classifier.

RESULTS

Differentiation between BLN and LM was most accurate, when using all CI-derived features combined with the most significant IM-derived feature, entropy (Accuracy:0.87; F1/Dice:0.92). However, differentiation accuracy based on the 4 most powerful CI-derived features performed only slightly inferior (Accuracy:0.84; F1/Dice:0.89, p=0.125). Mono-parametric lung nodule differentiation based on either feature alone (i.e. attenuation or iodine concentration) was poor (AUC=0.65, 0.58, respectively).

CONCLUSIONS

First-order texture feature analysis of contrast-enhanced staging SDCT scans of the chest yield accurate differentiation between benign and metastatic lung nodules. In our study cohort, the most powerful iodine map-derived feature slightly, yet insignificantly increased classification accuracy  compared to classification based on conventional image features only.

Baseline Chest Computed Tomography as Standard of Care in High-Risk Hematology Patients

Baseline chest computed tomography (BCT) in high-risk hematology patients allows for the early diagnosis of invasive pulmonary aspergillosis (IPA). The distribution of BCT implementation in hematology departments and impact on outcome is unknown. A web-based questionnaire was designed. International scientific bodies were invited. The estimated numbers of annually treated hematology patients, chest imaging timepoints and techniques, IPA rates, and follow-up imaging were assessed. In total, 142 physicians from 43 countries participated. The specialties included infectious diseases (n = 69; 49%), hematology (n = 68; 48%), and others (n = 41; 29%). BCT was performed in 57% (n = 54) of 92 hospitals. Upon the diagnosis of malignancy or admission, 48% and 24% performed BCT, respectively, and X-ray was performed in 48% and 69%, respectively. BCT was more often used in hematopoietic cell transplantation and in relapsed acute leukemia. European centers performed BCT in 59% and non-European centers in 53%. Median estimated IPA rate was 8% and did not differ between BCT (9%; IQR 5–15%) and non-BCT centers (7%; IQR 5–10%) (p = 0.69). Follow-up computed tomography (CT) for IPA was performed in 98% (n = 90) of centers. In high-risk hematology patients, baseline CT is becoming a standard-of-care. Chest X-ray, while inferior, is still widely used. Randomized, controlled trials are needed to investigate the impact of BCT on patient outcome.

2979The effect of proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitors on endothelial progenitor cells

Background

Endothelial progenitor cells (EPCs) have an important role in the process of vascular repair by promoting re-endothelialization following endothelial injury. We hypothesized that proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitors, which reduce cardiovascular events, will increase the level of EPCs and thus affect the process of vascular repair. Therefore, we sought to investigate the effect of PCSK9 inhibitors on circulating EPCs.

Methods

Study population included patients with known stable CAD who were initiated PCSK9 inhibitors. Blood samples were drawn and evaluated for EPCs at baseline and after treatment (1 month). Circulating EPCs were then assessed quantitatively by the expression of VEGFR-2, CD34 and CD133 using flow cytometry, and functionally by the formation of colony forming units (CFUs).

Results

Our preliminary cohort included 12 patients (median age of 69 years), 31% of whom were female. At baseline, total cholesterol and low density lipoprotein levels were 190 (IQR 180, 227) mg/dL and 123 (IQR 107, 154) mg/dL, respectively. Following 1-month of therapy with a PCSK9 inhibitor and along with a decrease in LDL to a median of 58 (IQR 50, 67) mg/dL, we observed an increase in the expression of CD34(+)/VEGFR-2(+) (1.2% (IQR 0.6, 1.6) to 3.0% (IQR 1.2, 4.5), P=0.07) and CD133(+)/VEGFR-2(+) (0.8% (IQR 0.7, 1.4) to 1.7% (IQR 0.6, 4.0), P=0.5). Proliferation of EPCs was confirmed microscopically (1 CFUs (IQR 1, 1.5) to 1.5 CFUs (IQR 1.5, 2.5), P=0.016) (Figure 1) and by an MTT assay (0.16 (IQR 0.12, 0.19) to 0.19 (IQR 0.17, 0.21), p=0.016).

Conclusions

These preliminary results in patients with CAD demonstrate that treatment with PCSK9 inhibitors is associated with higher levels of EPCs, thus promote endothelial repair. This finding may represent a novel mechanism of action of PCSK9 inhibitors, which might have important future clinical implications.

Effect of High Dose Statin Pretreatment on Endothelial Progenitor Cells After Percutaneous Coronary Intervention (HIPOCRATES Study)

BACKGROUND

Pretreatment with high-dose statins given before percutaneous coronary intervention (PCI) has been shown to have beneficial effects, in particular by reducing peri-procedural myocardial infarction. The mechanism of these lipid-independent beneficial statin effects is unclear. Circulating endothelial progenitor cells (EPCs) have an important role in the process of vascular repair, by promoting re-endothelization following injury. We hypothesized that statins can limit the extent of endothelial injury induced by PCI and promote re-endothelization by a positive effect on EPCs. We, therefore, aimed to examine the effect of high-dose statins given prior to PCI on EPCs profile.

METHODS

Included were patients, either statin naïve or treated chronically with low-dose statins, with stable or unstable angina who underwent PCI. Patients were randomized to receive either high-dose atorvastatin (80 mg the day before PCI and 40 mg 2-4 h before PCI) or low- dose statin. EPCs profile was examined before PCI and 24 h after it. Circulating EPCs levels were assessed by flow cytometry as the proportion of peripheral mononuclear cells co-expressing VEGFR-2+ CD133+ and VEGFR-2+ CD34+. The capacity of the cells to form colony forming units (CFUs) was quantified after 7 days of culture.

RESULTS

Twenty three patients (mean age 61.4 ± 7.4 years, 87.0% men) were included in the study, of which 12 received high-dose atorvastatin prior to PCI. The mean number of EPC-CFUs before PCI was higher in patients treated with high-dose atorvastatin vs. low-dose statins (165.8 ± 58.8 vs. 111.7 ± 38.2 CFUs/plate, respectively, p < 0.001). However, 24 h after the PCI, the number of EPC-CFUs was similar (188.0 ± 85.3 vs. 192.9 ± 66.5 CFUs/plate in patients treated with high-dose atorvastatin vs. low- dose statins, respectively, p = 0.15). There were no statistical significant differences in FACS analyses between the 2 groups.

CONCLUSIONS

The current study showed higher EPC- CFUs levels in patients treated with high-dose atorvastatin before PCI and a lower increment in EPC-CFUs after PCI. These findings could account for the beneficial effects of statins given prior to PCI, yet further investigation is required.

Acute myocardial infarction following sildenafil citrate (Viagra) intake in a nitrate-free patient

Since its introduction to the market in March 1997, sildenafil acetate (Viagra) has been prescribed to 1.7 million people. Sixteen men who were taking the drug have died, 7 of them during or soon after sexual activity. Most of these data have been derived from the media and not from the scientific literature. There is a general impression that cardiovascular complications of sildenafil occur mainly when the drug is taken concomitantly with nitrates. We describe a 65-year-old man with known coronary artery disease who had an acute myocardial infarction shortly after taking sildenafil and engaging an sexual activity. The patient had not been using nitrates. We suggest that the emotional arousal induced by Viagra, followed by the heavy physical exertion during sexual activity, triggers plaque rupture that leads to acute myocardial infarction.

Influence of the rate of contrast change on the quality of contrast sensitivity assessment: a comparison of three psychophysical methods

Criterion-free forced-choice procedures for measuring contrast sensitivity with a cathode ray tube (CRT) have low within-subject, intersubject, and test-retest variabilities, but a long test time compared with psychophysical methods that rely on the subject's criterion to determine threshold. Test time and variability of criterion-dependent methods depend on the rate at which the contrast changes on the CRT display. This study compared two criterion-dependent psychophysical methods for measuring contrast sensitivity (the method of increasing contrast and the von Békésy tracking method) with a criterion-free two-alternative forced-choice procedure. A range of rates of contrast change was studied: 0.1, 0.3, 0.5, 0.7 and 1.0 log unit s-1. Contrast sensitivity, within-subject variability, intersubject variability, test-retest variability, and test time of the three methods were compared. The 2-AFC procedure performed best with regard to within-subject, intersubject, and test-retest variabilities. A time-efficient alternative was the von Békésy tracking method at rates between 0.1 and 0.5 log unit s-1.

Acute left ventricular failure after large volume pericardiocentesis

This paper reports on two cases of large volume pericardiocentesis followed by transient severe acute left ventricular (LV) systolic failure in the absence of any prior history of LV dysfunction. Acute LV volume overload due to interventricular volume mismatch is believed by most authors to be the cause for this phenomenon. Another plausible physiopathologic explanation is the acute increase in "wall stress" (Laplace's law) due to acute distention of the cardiac chambers secondary to a sudden increase in venous return at high filling pressures, combined with a "vacuum" effect of the evacuated pericardial space.

Prediction of the extent and severity of left ventricular dysfunction in anterior acute myocardial infarction by the admission electrocardiogram

BACKGROUND

The grade of ischemia, as detected by the relation between the QRS complex and ST segment on the admission electrocardiogram, is associated with larger infarct size and increased mortality rates in acute myocardial infarction.

METHODS

We assessed the correlation between left ventricular function and the admission electrocardiogram in 151 patients with first anterior acute myocardial infarction who received thrombolytic therapy and underwent cardiac catheterization at 90 minutes and before hospital discharge. The number of leads with ST elevation, sum of ST elevation, maximal Selvester score, and the presence of severe (grade 3) ischemia were determined in each electrocardiogram. Left ventricular ejection fraction, the number of chords with wall motion abnormalities, and the severity of dysfunction (SD/chord) were determined.

RESULTS

At 90 minutes, the 39 ischemia grade 3 patients had lower ejection fraction than the 112 grade 2 patients. Both at 90 minutes and at hospital discharge, the grade 3 group had more chords with wall motion abnormalities and more severe regional dysfunction (SD/chord). However, the number of leads with ST elevation, sum of ST elevation, and maximal Selvester score had no correlation with ejection fraction at 90 minutes and only mild correlation with the extent of dysfunction (number of chords) at 90 minutes. There was no correlation between either the number of leads with ST elevation or the sum of ST elevation and the severity of regional dysfunction.

CONCLUSIONS

The number of leads with ST elevation, sum of ST elevation, and maximal Selvester score had only mild correlation with the extent of myocardial dysfunction but not with the severity of dysfunction. Grade 3 ischemia is predictive of more extensive myocardial involvement and greater severity of regional dysfunction.

Value of the initial electrocardiogram in patients with inferior-wall acute myocardial infarction for prediction of multivessel coronary artery disease

BACKGROUND

Patients with inferior-wall acute myocardial infarction (AMI) who have ST-segment depression in the left precordial leads (LSTD+) on the initial electrocardiogram were reported to have more diffuse coronary artery disease (CAD) than had those without this finding (LSTD-). This suggests that LSTD+ patients may need extensive revascularization interventions more often than do LSTD- patients. However, this has not yet been confirmed.

OBJECTIVE

To compare the coronary angiographic findings and treatment strategies for patients with inferior-wall AMI according to the LSTD pattern.

METHODS

The clinical outcomes and the angiographic findings for 238 consecutive patients aged < or = 75 years who had been admitted to our hospital between 1 February 1995 and 1 February 1997 with inferior-wall AMI were retrospectively analyzed. The patients were divided into two groups according to the pattern of precordial ST-segment depression: LSTD+, ST-segment depression in leads V4-V6; and LSTD-, absence of this finding. All patients were treated according to current practice guidelines including with thrombolysis and revascularization interventions.

RESULTS

The final study population included 217 patients; 83 were LSTD+ and 134 were LSTD-. All underwent coronary angiography within 30 days of the infarction. Compared with LSTD- patients, LSTD+ patients tended to be older (mean age 62.7 +/- 11.7 versus 58.3 +/- 9.6 years, P = 0.004), and had higher incidences of hypertension (39.8 versus 24.6%, P = 0.019) previous myocardial infarction (45.8 versus 20.1%, P = 0.0001) and congestive heart failure (21.7 versus 3.7%, P = 0.00008). Three-vessel CAD was much more common, and single-vessel CAD much less common, in the LSTD+ than in LSTD- group (62.7 versus 13.4% and 8.4 versus 50.7%, P < 0.00001 for both). Coronary-artery-bypass surgery and multivessel percutaneous coronary interventions (PCI) were used in treating 65.1% of the LSTD+ versus only 6.0% of the LSTD- patients (P < 0.00001), whereas single-vessel PCI was used in treating 71.6% of the LSTD- patients versus only 24.1% of the LSTD+ patients (P < 0.00001). Thus, the LSTD- pattern predicted single-vessel disease and single-vessel PCI only, whereas the LSTD+ pattern was predictive of multivessel CAD and of use of coronary-artery-bypass surgery or multivessel PCI (predictive values of 94.0 and 65.1%, respectively).

CONCLUSIONS

Among patients with inferior-wall AMI, left precordial ST-segment depression predicts a very high prevalence of multivessel CAD and use of extensive revascularization interventions. The absence of this finding predicts nondiffuse CAD and lack of a need for extensive revascularization.

Relation between evolutionary ST segment and T-wave direction and electrocardiographic prediction of mycardial infarct size and left ventricular function among patients with anterior wall Q-wave acute myocardial infarction who received reperfusion therapy

In the prethrombolytic era it was found that infarct size and left ventricular ejection fraction could be predicted using the Selvester QRS score. We evaluated whether infarct size and left ventricular ejection fraction could be predicted by the predischarge QRS score in patients who had received reperfusion therapy and whether considering the configuration of the ST segments and T waves would increase the accuracy of these predictions. We evaluated 51 patients with first anterior wall myocardial infarction who had received reperfusion therapy and predischarge resting technetium-99m-sestamibi scan. The electrocardiograms recorded on the same day of the scan were analyzed for the QRS score and were divided into 3 groups: A, isoelectric ST and negative T waves; B, ST elevation (> or =0.1 mV) and negative T waves; and C, ST elevation (> or =0.1 mV) and positive T waves. Groups A, B, and C included 12, 23, and 16 patients, respectively. The myocardial perfusion defect extent increased from groups A to C (median 21%, 37%, and 43.5% in groups A, B, and C, respectively; p = 0.023). Similarly, left ventricular ejection fraction decreased (44%, 38%, and 34%, respectively; p = 0.042) from groups A to C. Overall, the correlation between the QRS score and the myocardial perfusion defect extent (rho 0.249; p = 0.08) and ejection fraction (rho -0.229; p = 0.11) was poor. A statistically significant correlation between myocardial perfusion defect size and QRS score was found only in group A (rho 0.599, p = 0.04). Among patients with anterior myocardial infarction who received reperfusion therapy, the predischarge QRS score was predictive of infarct size only in those in whom ST elevation resolved completely. In patients with residual ST elevation there was no correlation between QRS score and infarct size.

Methylenetetrahydrofolate reductase genotypes and early-onset coronary artery disease

BACKGROUND

Homozygosity for the common (677C-->T) mutation in the methylenetetrahydrofolate reductase (MTHFR) gene is associated with hyperhomocysteinemia, but there is uncertainty as to the association between this mutation and coronary artery disease (CAD). This study examined the association between MTHFR genotypes and age at onset of CAD.

METHODS AND RESULTS

Patients (n=169) with documented myocardial infarction or angiographically documented CAD who were aged < or = 55 years at onset of CAD symptoms and DNA samples from control subjects (n=313) were studied. The prevalence of homozygosity among patients with early CAD onset (aged < or = 45 years) was 28%, which was significantly higher than that in patients with later onset (13%) and in control subjects (14%) (odds ratio 2.4, 95% CI 1.24 to 4.69, P=0.006, and odds ratio 2.7, 95% CI 1.15 to 6.42, P=0.01, respectively). Plasma folate was lower in TT homozygotes who had early CAD onset than in those with later onset (P=0.005). Among patients with plasma folate in the lowest quintile (< or = 12.6 nmol/L), 31% were homozygotes, as were 45% of those with low plasma folate and early CAD onset. There was no difference in the prevalence of traditional risk factors among genotypes. The frequency of homozygosity in patients with < or = 1 risk factor was higher than in those with > or = 2 risk factors (30% versus 12%, P<0.05). In multiple regression analysis, TT homozygosity and plasma folate were independently associated with CAD, but the impact of folate was small.

CONCLUSIONS

Homozygosity for the 677C-->T mutation of MTHFR is common and is associated with an increased risk of premature CAD in this population.

Terminal QRS distortion on admission is better than ST-segment measurements in predicting final infarct size and assessing the Potential effect of thrombolytic therapy in anterior wall acute myocardial infarction

We assessed predicting final infarct size (using predischarge Selvester score) by 3 electrocardiographic variables in 267 patients with first anterior wall acute myocardial infarction (AMI) undergoing (n = 86) or not undergoing (n = 181) thrombolysis. Patients with previous AMI or inverted T waves in leads with ST elevation were excluded. The sum (sigma) of ST elevation, the number of leads with ST elevation, and the initial electrocardiographic pattern were determined on the admission electrocardiogram (absence (QRS-) or presence (QRS+) of distortion of the terminal portion of the QRS in > or =2 leads (J point > or =0.5 of the R-wave amplitude in leads I, aVL, V4 to V6, or presence of ST elevation without S waves in leads V1 to V3). There was no association between sigmaST elevation and final infarct size in patients who did or did not receive thrombolytic therapy. Analysis of covariance showed that the number of leads with ST elevation (F = 19.6), thrombolysis (F = 25.2), and QRS+ initial pattern (F = 19.5) were all associated with final infarct size (p <0.0001 for all). Among patients who did not receive thrombolytic therapy, the average Selvester score was 19.7+/-9.9 for the QRS- patients and 26.1+/-10.4 for the QRS+ patients (p = 0.02). Among patients who received thrombolytic therapy, the average Selvester score was 11.7+/-9.8 for the QRS- patients and 24.2+/-10.1 for the QRS+ patients (p <0.0001). Thrombolysis reduced final Selvester score only in the QRS- group (p <0.00001), but not in the QRS+ group (p = 0.45). It is concluded that (1) final Selvester score in anterior wall AMI can be predicted by the number of leads with ST elevation, the initial electrocardiographic pattern, and thrombolysis, and (2) thrombolysis reduces final Selvester score only in patients with QRS- pattern.

QRS complex distortion predicts no reflow after emergency angioplasty in patients with anterior wall acute myocardial infarction

BACKGROUND

In patients with acute myocardial infarction, distortion of the terminal portion of the QRS complex on the electrocardiogram (ECG) at the time of their admission to hospital is associated with larger final infarct size and greater mortality. This study assessed the results of emergency coronary angioplasty in patients with anterior acute myocardial infarction with and without distortion of the terminal portion of the QRS complex on the admission ECG.

METHODS

We assessed the Thrombolysis in Myocardial Infarction (TIMI) trial flow grade, resolution of ischemic ECG changes, and clinical outcome after emergency angioplasty for acute anterior wall myocardial infarction in patients with (n = 21) and without (n = 21) distortion of the terminal portion of the QRS complex on the admission ECG.

RESULTS

Compared with patients without distortion of the terminal portion of the QRS complex on the admission ECG, those with distortion had a significantly lower incidence of TIMI flow grade 3 (52% compared with 84%, P < 0.05), lower rate of resolution of the ischemic ECG changes (33% compared with 84%, P < 0.005), and greater rate of mortality during their stay in hospital despite successful balloon angioplasty (19% compared with 0%, P < 0.05).

CONCLUSIONS

In patients with anterior wall acute myocardial infarction, distortion of the terminal portion of the QRS complex on the admission ECG predicts a greater mortality rate and a greater incidence of reflow impairment after emergency angioplasty.

Clinical significance and predisposing factors to symptomatic bradycardia and hypotension after percutaneous transluminal coronary angioplasty

Of 180 consecutive patients who underwent uneventful percutaneous transluminal coronary angioplasty (PTCA), 25 (13.9%) had at least 1 episode of symptomatic bradycardia and hypotension during the early postprocedure period. Symptomatic bradycardia and hypotension occurred 1 to 10 hours (mean 4 +/- 2) after PTCA. A higher incidence of symptomatic bradycardia and hypotension was found in patients receiving regular treatment with beta blockers (26% vs 10% in patients without beta blockers in their regimen, p < 0.01), diltiazem or verapamil (20% vs 9%, p < 0.025), or both a beta blocker and diltiazem or verapamil (64% vs 11%, p < 0.001). A higher incidence was also associated with angioplasty of the left anterior descending coronary artery compared with angioplasty of the other coronary arteries (22% vs 8%, p < 0.01). It is concluded that symptomatic bradycardia and hypotension is a common occurrence after PTCA. The incidence is higher after PTCA to the left anterior descending coronary artery and in patients receiving diltiazem, verapamil, and beta-blocking agents; it is particularly high in patients receiving a combination of a beta-blocking agent and either diltiazem or verapamil.

T cell proliferative response to bovine leukaemia virus (BLV): identification of T cell epitopes on the major core protein (p24) in BLV-infected cattle with normal haematological values

Peripheral blood mononuclear cells (PBMCs) from bovine leukaemia virus (BLV)-seronegative cattle and from BLV-seropositive cows either with normal haematological values or persistent lymphocytosis were tested for their proliferative response to BLV antigens. Cells from only BLV-infected cattle with normal lymphocyte counts were stimulated to a detectable level by the fetal lamb kidney cell supernatant containing BLV antigens. Proliferation assays performed with the purified major core protein p24 indicated that this protein has to be processed through a chloroquine-sensitive compartment before being recognized by CD4+ T lymphocytes. Forty-one 15-mer overlapping peptides spanning the entire p24 sequence were synthesized and analysed for their stimulating potential. It appeared that two regions included T cell epitopes recognized by PBMCs from three of five animals tested. These regions were represented by amino acids 31 to 55 (PGSQVWIQTLRLAILQADPTPADLE) and 141 to 165 (AESYVEFVNRLQISLADNLPDGVPK). The possible implication of this cell-mediated immune response in BLV pathogenesis and vaccine development is discussed.

Prediction of arrhythmic events after acute myocardial infarction using two methods for late potentials recording

One hundred consecutive patients recovering from an acute myocardial infarction underwent, prior to home discharge, signal-averaged electrocardiography (ECG), left ventriculography, and 24-hour Holter ECG recording. The signal-averaged ECG was recorded and analyzed using two procedures: the orthogonal bipolar XYZ lead configuration with a bidirectional filter; and a precordial unipolar lead configuration with a nonrecursive digital filter. An abnormal signal-averaged ECG was seen in 40% of patients with the XYZ system and in 30% of patients in the precordial method, abnormal ejection fraction (< 40%) in 24% of patients and high grade ectopy activity in 22%. During the 24-month follow-up period, 12 patients (12%) had an arrhythmic event defined as either sudden death (11 patients) or sustained ventricular tachycardia (1 patient). Neither the signal-averaged ECG with the XYZ configuration, the abnormal ejection fraction, nor the high grade ectopy were able to statistically predict a higher arrhythmic event rate. The signal-averaged ECG with the precordial configuration was able to statistically predict a higher arrhythmic event rate, P < 0.03; odds ratio = 3.96. The combination of the orthogonal XYZ configuration signal-averaged ECG with the ejection fraction (P < 0.01, odds ratio = 7.33), or with ejection fraction and Holter monitoring (P < 0.06, odds ratio = 6.17) was able to predict a higher arrhythmic event rate. The combination of the precordial configuration signal-averaged ECG with the ejection fraction (P < 0.002, odds ratio = 14.4), or with ejection fraction and Holter monitoring (P < 0.06, odds ratio = 10) was able to better predict a higher arrhythmic event rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Mapping of B-neutralizing and T-helper cell epitopes on the bovine leukemia virus external glycoprotein gp51

A battery of 19 synthetic peptides was used to characterize efficient neutralizing and helper T-cell epitopes on the bovine leukemia virus (BLV) external envelope glycoprotein gp51. Four of the antipeptide antisera raised in rabbits inhibited the formation of BLV-induced syncytia; these antisera are directed against peptides 64-73, 98-117, and 177-192. Only antisera directed against the 177-192 region also neutralized vesicular stomatitis virus-BLV pseudotypes. This study clearly demonstrates that neutralizing properties can be observed with antibodies raised to regions undescribed so far and included in both the amino-terminal and central parts of the antigen. In addition, some helper T-cell determinants were defined from gp51-immunized mice and from BLV-infected cattle. Although none of the peptides tested behaved as a universal helper T-cell epitope, peptide 98-117 stimulated T-cell proliferation from BALB/c mice and from three infected cows, while peptide 169-188 strongly stimulated T-cell proliferation from one infected cow. Further experiments performed with three peptides overlapping the 169-188 region (177-192, 179-192, 181-192) demonstrated the particular relevance of residue(s) P-177 and/or D-178 in the helper T-cell epitope. These data should assist in the design of an efficient subunit vaccine against BLV infection that contains peptides possessing both B-neutralizing and helper T-cell determinants.

Prognostic significance of the initial electrocardiographic pattern in a first acute anterior wall myocardial infarction

The availability of potent, but potentially dangerous, types of reperfusion therapy for acute myocardial infarction (AMI) has forced us to refine our tools for early and accurate diagnosis and for early risk stratification of patients with evolving AMI. The estimation of risk has to be made shortly after admission, when only the history, physical examination, and the ECG are available. This study was undertaken to compare in-hospital mortality with different patterns of the ECG obtained at admission in 147 consecutive patients with an evolving first AMI of the anterior wall. By using a new classification of the admission ECG, it was possible to divide the patients into 3 groups: (1) group A contained 12 patients with tall peaked T waves in the involved leads, without ST segment elevation; (2) group B comprised 77 patients with abnormal T waves and ST elevation, but without major changes in the terminal portion of the QRS complex; and (3) group C comprised 58 patients with abnormal T waves, ST elevation, and distortion of the terminal portion of the QRS. The mortality was 0, 3 percent, and 29 percent in groups A, B, and C, respectively (chi 2 = 22.91; p = 0). By using a logistic regression model, it was found that the initial ECG pattern alone is a strong predictor of in-hospital mortality in patients with an evolving anterior wall AMI. The predicted probabilities of death in groups A, B, and C are 0.0016, 0.025, and 0.29, respectively. This simple classification of the initial ECG pattern in patients with a first AMI of the anterior wall may enable the differentiation of patients with low in-hospital mortality (groups A and B) and of those with an in-hospital mortality of almost 30 percent (group C).

ST segment depression in a VL: a sensitive marker for acute inferior myocardial infarction

In a substantial percentage of patients with acute myocardial infarction, especially in those with inferior wall involvement, no ST elevation is detected on the electrocardiogram. In many of them, ST depression is found in leads oriented to remote segments of the heart. The importance of those reciprocal changes for early diagnosis of acute inferior myocardial infarction in patients without ST elevation has not been stressed. In order to find the prevalence of reciprocal ST depression, we evaluated the admission electrocardiograms of 107 consecutive patients with evolving first acute inferior myocardial infarction. Ninety-three patients had ST elevation of at least 0.1 mV in at least one of the inferior leads: II, III or aVF (group A) and in 14 patients ST displacement did not reach 0.1 mV in any of these leads (group B). In both groups, reciprocal ST depression occurred more frequently in aVL than in any other lead. Only three patients had no ST depression in aVL. In eight patients (7.5%) ST depression in aVL was the sole early electrocardiographic sign of the inferior infarction. aVL is the only lead that is facing the superior part of the left ventricle and thus is the only lead that is truly opponent to the inferior wall. It seems that ST depression in aVL, by contrast to that in the precordial leads, is found in the majority of patients with evolving inferior wall myocardial infarction and is not influenced by extension of the infarction to the right ventricle or to the posterior wall.(ABSTRACT TRUNCATED AT 250 WORDS)

The incidence of atrial arrhythmias during inferior wall myocardial infarction with and without right ventricular involvement

The atrial arrhythmia profile during inferior wall acute myocardial infarction (AMI) has not been systematically examined with respect to right ventricular (RV) involvement. To this end, 62 consecutive patients with first inferior wall AMI and no other conditions known to increase susceptibility for rhythm disturbances were studied by 24-hour Holter monitoring during the first and tenth day of infarction. Based on radionuclear ventriculography performed on day 2 of infarction, patients were allocated to two groups: group A--36 patients (58%) with right ventricular ejection fraction (RVEF) less than 40% (mean +/- SD, 31 +/- 6%) and group B--26 patients (42%) with normal (greater than 40%) RVEF (mean +/- SD, 47 +/- 5%). There were no significant differences between the two groups with respect to age, sex, or left ventricular (LV) function. In the group as a whole, ectopic activity in the different categories of atrial arrhythmias was significantly higher during the first day than on the tenth day of infarction. Comparing the two groups, 33 patients (92%) in group A had a mean hourly frequency of one or more atrial premature contractions (APCs) during the first day of infarction compared with 18 patients (69%) in group B (p less than 0.001). Atrial and supraventricular tachycardia were recorded more frequently in group A patients (16 of 36 [44%] versus 8 of 26 [31%]) as well as atrial fibrillation (AF) (7 of 36 [19%] versus 1 of 26 [4%]). Quantitative analysis showed a similar trend for a higher rate of ectopic events in group A patients. Ectopic activity was neither influenced by LVEF nor by age or sex.(ABSTRACT TRUNCATED AT 250 WORDS)

CD5+ B cells from bovine leukemia virus infected cows are activated cycling cells responsive to interleukin 2

Most of the B cells from bovine leukemia virus (BLV) infected cows in persistent lymphocytosis (PL) were known to express the CD5 T-cell marker but it was not known whether this peculiar membrane phenotype relates to an activation state. It was demonstrated that these B cells were also flagged by two other membrane markers normally borne by cells belonging to the myeloid lineage (namely CD11b and CD11c). Moreover, cell cycle analysis illustrated that a significant percentage of these B cells (greater than 15%) left their resting (G0/G1) status and progressed through the cell cycle. In addition, T-cell-depleted peripheral blood mononuclear cells from animals in PL were shown to proliferate in response to a IL-2-containing supernatant (MLA 144). These results indicate that the CD5+ B cells from BLV-infected cows in PL are activated cells.

Electrocardiographic Q-waves inconstancy during thrombolysis in acute anterior wall myocardial infarction

It is the purpose of this paper to describe the electrocardiographic inconstancy of Q-waves during administration of thrombolytic therapy. This was documented in four patients given streptokinase early in the course of anterior wall myocardial infarction. Understanding the pathogenesis of sequential dynamic variations of Q-waves in this setting may offer important insights into coronary physiology and management of acute coronary events. We discuss the possible explanations for such changes with respect to tissue viability, dynamic vascular changes and electrophysiological properties of the reperfused infarcted myocardium.

S-T segment depression in right-sided precordial leads during acute inferior wall infarction

Right-sided chest leads (V3-V4R) were recorded in the early stages of first inferior wall acute myocardial infarction (AMI) in 100 consecutive patients. Nine patients (9%) presenting with S-T segment depression (greater than 1 mm) in these leads were subsequently studied by echocardiography and radionuclear angiography. In this group, there were 5 patients with intact right ventricular (RV) function and 4 other patients with clinical findings compatible with RV infarction. We suggest that one should not rule out RV involvement when S-T segment depression rather than elevation is seen in the right precordial leads in the presence of inferior wall AMI. An individual assessment for RV infarction is recommended when this pattern is apparent on the ECG.

Life-threatening ventricular tachycardia as the presenting symptom of metastatic cardiac disease

We present 2 cases in whom repetitive rapid ventricular tachycardia (VT) was the initial manifestation of metastatic cardiac disease. In one patient, repetitive VT appeared during chemotherapy for stage IV paratesticular rhabdomyosarcoma which led to the diagnosis of cardiac metastases. In the other, it led to the diagnosis of malignant pericardial effusion 17 years after successful therapy for a breast carcinoma. In conclusion, in patients with present or past history of malignancy, the appearance of life-threatening VT should raise the suspicion of cardiac metastases.

Prazosin's effect in high renin hypertension complicating pheochromocytoma

During three consecutive days of prazosin treatment in a patient with pheochromocytoma, urinary catecholamine metabolite levels were correlated with plasma renin activity. Suppression of renin plasma activity resulted in sustained hemodynamic and clinical improvement, while no remarkable changes were observed in urinary catecholamine metabolite levels. This suggests that prazosin may interrupt the vicious cycle of worsening hypertension provoked by further activation of the renin-angiotensin system mediated by excessive circulating catecholamines.

Ischemia and reperfusion during intermittent coronary occlusion in man. Studies of electrocardiographic changes and CPK release

The course of 357 balloon inflations performed during 38 angioplasties for single-vessel coronary artery disease was prospectively studied using continuous ECG recording. Ischemic ECG changes appeared during 91 percent of the inflations at a mean of 20 +/- 8 seconds after inflation and resolved in 97 percent of those at a mean of 11 +/- 5 seconds after deflation. Elevation of the plasma CPK level was found in six patients who had ischemic ECG changes for at least 7.8 minutes. The duration of ischemia did not exceed 5.4 minutes in any of the patients without CPK elevation. Resolution of the ischemic changes was delayed in patients with CPK elevation and in last vs initial inflations. We conclude that in patients with noninfarcted myocardium, ECG changes follow coronary occlusion and reflow very rapidly, detecting these coronary events with a high sensitivity. Lack of rapid regression predicts lack of reperfusion, and persistence of ischemia for more than 7.8 minutes is sufficient to cause myocardial necrosis.

FACS analysis of bovine leukemia virus (BLV)-infected cell lines with monoclonal antibodies (mAbs) to B cells and to monocytes/macrophages

The eighteen monoclonal antibodies (mAbs) to B cells and the fourteen mAbs to accessory cells submitted to the workshop were analysed by FACS on three established, bovine leukemia virus (BLV)-infected bovine cell lines. Several mAbs of previously defined specificity were run in parallel. This analysis allowed us to gain further insight on the precise phenotype of those peculiar cells and to cluster the submitted mAbs according to their staining patterns. The BLV-infected cell lines seemed to belong to the B cell type though some of them lack detectable surface immunoglobulins. Moreover, all lines express the CD5 T cell marker and several myeloid markers.

The impact of right ventricular infarction on the prevalence of ventricular arrhythmias during acute inferior myocardial infarction

To determine the impact of RV infarction on the prevalence and complexity of ventricular arrhythmias during inferior AMI, 57 patients with no prior MI were studied by 24-hour Holter monitoring on the first and tenth days of AMI. Based on radionuclear studies, patients were allocated into two groups: (1) group A, 21 patients (37 percent) with normal RVEF (greater than or equal to 40 percent); and (2) group B, 36 patients (63 percent) with depressed RVEF (less than 40 percent). There were no significant differences between the groups regarding age and LVEF. Values of RVEF were 47 +/- 6 percent and 31 +/- 6 percent, respectively (p less than 0.05). The RVEF had no influence on the prevalence and complexity of early and late arrhythmias. Stratification of patients in group B into two subgroups based on the extent of RV dysfunction did not reveal any differences in the occurrence of all forms of ectopy (when both groups were matched to group A). Therefore, patients with inferior AMI, with or without RV infarction, have a similar prevalence of arrhythmias. Ventricular ectopic beats may be related to the severity and spread of LV involvement, rather than to RV dysfunction.

Long-term follow-up of postmyocardial infarction patients with ventricular tachycardia or ventricular fibrillation treated with amiodarone

Amiodarone in a low dose (200 mg/day) was administered alone or in combination with other type I antiarrhythmic drugs as a first-line agent in 33 patients with ventricular tachycardia (VT) (n = 24) or ventricular fibrillation (VF) (n = 9) secondary to coronary artery disease with healed myocardial infarction. There were 30 men and 3 women (mean age 69 +/- 9 years). Left ventricular ejection fraction ranged from 16 to 45% (mean 29 +/- 8). Therapy was guided by the results of electrophysiologic studies without the use of a control study (without drugs). Predischarge electrophysiologic studies revealed inducible sustained VT in 8 patients (24%), nonsustained VT in 7 and noninducible VT in 18 patients. Mean follow-up time was 27 +/- 7 months. Eleven patients (33%) died, 5 suddenly (15%) and 6 from nonarrhythmic causes. Five patients (15%) had nonfatal recurrences of VT. Life-table analysis showed that arrhythmic recurrences or fatalities (VT or sudden death) were related to the results of the predischarge electrophysiologic studies and not to the baseline arrhythmia (VT or VF). Toxicity from amiodarone was uncommon and no patient discontinued taking the drug.

Monoclonal antibody specific for bovine CD 5 antigen which enhances mitogen-induced blastogenesis and IL-2 production

This study reports on the functional characteristics of a bovine T-cell differentiation antigen recognized by the monoclonal antibody (mAb) 8C11. This mAb has previously been found to react with a 67-kD molecule shared by thymocytes and peripheral blood T cells and to be undetectable on the B cells of healthy animals. This antigen is also largely expressed on the B cells from bovine leukemia virus-infected animals. Molecules with a similar cell distribution have been described in other species (mouse, human, rat and sheep), and were termed CD5 molecules. In order to confirm the CD5-like nature of the target molecule recognized by 8C11, functional T-cell assays were carried out. We report here that this mAb, like its human and murine homologues, enhances the proliferative responses of T cells to mitogens or alloantigens but does not directly stimulate T-cell division. Moreover, we have shown an enhancing effect of this 8C11 mAb on bovine interleukin-2 production by concanavalin A-stimulated bovine peripheral blood mononuclear cells.

B cells from bovine leukemia virus- (BLV) infected sheep with hematological disorders express the CD5 T cell marker

Though peripheral blood B cells from healthy sheep were known to be devoid of the CD5 T cell marker, it appears from our study that most B cells from bovine leukemia virus- (BLV) infected sheep with hematological disorders express both the CD5 marker and surface IgM. The possible meaning of this T cell marker expression on B cells from BLV-infected sheep is briefly discussed.

The head-up tilt table test in patients with syncope of unknown origin

Forty patients with recurrent syncopal episodes of uncertain etiology were evaluated with a 60-degree head-up tilt table test for 60 minutes. There were 21 men and 19 women, with a mean age of 36 +/- 19 years, a mean of 7.6 syncopal episodes per patient, and a mean duration of symptoms of 4.2 +/- 6 years. Twelve patients had evidence of organic heart disease. Ten control subjects with no history of syncope were studied similarly. Syncope did not occur in any of these controls. Syncope occurred in 15 patients (37.5%) after a mean standing time of 42 +/- 12 minutes. Syncope was due to a typical vasovagal reaction in 11 patients and to hyperventilation in three patients. One last patient fainted without changes in heart rate or blood pressure. In each case, symptoms during the test resembled those previously experienced.

Surgical removal of echocardiographically detected multiple pedunculated and mobile left ventricular thrombi in acute myocardial infarction

Two-dimensional echocardiography revealed at least three left ventricular mural thrombi in a 59-year-old man with acute anterior myocardial infarction. The thrombi, which had highly mobile pedunculated elements, were attached to the septo-apical wall and protruded into the left ventricular cavity. In spite of the lack of a clinical event but in view of the potential risk of embolization, surgical removal of the thrombi was performed on the 16th day of hospitalization.

[Classification of acute myocardial ischemia by electrocardiography]

Electrocardiographic recording during chest pain is usually performed for detection of myocardial ischemia and localization of the affected area. By analyzing changes in electrocardiograms recorded during chest pain, pathophysiological mechanisms of ischemia, prediction of coronary pathology, and the risk of evolution to myocardial infarction can be determined. Myocardial ischemia is caused by either an increase in O2 demand, reduction in coronary flow, or both. The former is manifested by tachycardia and in such patients measures should be taken to slow the heart rate. Patients with ischemia without tachycardia suffer from reduction of coronary flow and therapy should be aimed at increasing flow. We classify patients with ischemia but without tachycardia according to electrocardiographic patterns recorded during chest pain by precordial leads as follows: group 1, those with ST segment elevation and with positive T waves; group 2, ST segment depression and negative T waves; and group 3, ST depression and positive T waves. Group 1 patients have anterior wall ischemia and the left anterior descending artery is usually involved. They are possible candidates for coronary angiography. In group 2, the electrocardiographic changes reflect extensive subendocardial myocardial ischemia. We found severe coronary artery disease (LMCA or right main artery equivalent) in 69% of such patients, and the mortality in those with subsequent myocardial infarction was 77%, mainly due to pump failure. When this latter electrocardiographic pattern is found, intervention should be prompt, and surgery rather than angioplasty is usually necessary. Patients with ischemic ST depression maximal in V2-V3 should not be included in this group since these changes are reciprocal with posterolateral wall ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

The natural course of electrocardiographic stages of acute inferior myocardial infarction in regard to R/Q ratio group classification

Forty-three patients with their first acute inferior wall myocardial infarction (IWMI) were divided into three groups according to the R/Q ratio in standard lead II. This was done to correlate these groups with the characteristic course of electrocardiographic stages. The R/Q ratio was measured on the ninth day of follow-up study, and the electrocardiographic stages were followed from the onset of the IWMI up until the ninth day. Patients with R/Q greater than 2 (group I) had a more rapid progression through the electrocardiographic stages, along with a better clinical course than patients with a lower R/Q ratio. Patients in group III, with R/Q less than 1, had a slower electrocardiographic stage progression, which correlates well with a more complicated clinical course. Group II was an intermediate group in both the electrocardiographic and clinical course. Rapid stage evolution in the first 12 hours of the IWMI was followed by a more rapid progression through stages during the rest of the follow-up period. It is suggested that the R/Q ratio in lead II can be used as a marker of the severity of IWMI, since it correlates well with the course of electrocardiographic stages. The greater the R/Q ratio, the more rapid the progression of electrocardiographic stages, and the better the clinical course. This may be an additional simple and inexpensive electrocardiographic tool for following the natural course of IWMI.

Unstable angina: ST segment depression with positive versus negative T wave deflections--clinical course, ECG evolution, and angiographic correlation

Thirty-two consecutive patients who initially had horizontal or downward-sloping ST segment depression confined to the precordial leads were studied. Patients were divided into two groups: group A included 21 patients with horizontal or downward-sloping ST depression with peaked positive T waves, and group B comprised 11 patients with peaked negative T waves and downward or horizontal ST depression. The incidence of acute myocardial infarction (AMI) was similar (group A 38.1% vs group B 36.4%; p greater than 0.05). In-hospital mortality was much more significant in group B (p = 0.03). Coronary arteriography was performed in 31 patients. Of the 10 patients in group B who were catheterized, seven (70%) had left main occlusion. Of the 21 patients in group A, none had a significant left main lesion (p = 0.001), although eight (38.1%) had single-vessel disease (p = 0.05). Thus the ECG pattern of horizontal or downward-sloping ST depression passing into a peaked negative T wave identifies a subgroup of high-risk patients in whom the prognosis is poor once AMI occurs. Early catheterization is recommended when this ischemic pattern is apparent on the ECG.

Repetitive ventricular fibrillation preceded by both ST segment depression and elevation during acute myocardial ischemia

A patient had repetitive ventricular fibrillation preceded by alternating ST segment depression and elevation. The ECG changes were confined to the precordial leads only, reflecting subendocardial and transmural ischemia, respectively. It is speculated that the patient exhibited consecutive episodes of subtotal and total coronary occlusion, both episodes being critical enough to induce lethal arrhythmias.