[Stress thallium-201 myocardial emission CT: comparative evaluation with coronary arteriography and left ventriculography]

Thallium-201 emission computed tomography (ECT) using a rotating gamma camera was performed during stress and redistribution phases in 70 cases admitted for cardiac catheterization. A series of transaxial, ventricular short-axis, and long-axis sections were reconstructed, and segmental analysis was performed to predict individual coronary artery involvement. A perfusion defect was observed in 54 of 57 cases with coronary artery disease (95%). Ninety of 108 diseased coronary arteries (83%) were correctly identified (91% of single-vessel disease, 82% of two-vessel disease and 80% of three-vessel disease). No significant perfusion defect was seen in 11 of 13 cases with normal coronary arteries (specificity 85%). Number of diseased coronary arteries was accurately predicted in 78% of those with single-vessel disease, 65% of those with two-vessel disease and 47% of those with three-vessel disease, indicating relatively poor accuracy for predicting multivessel disease. The sensitivity for detecting individual coronary artery involvement was 90% for the right coronary artery (RCA), 89% for the left anterior descending artery (LAD) and 67% for the left circumflex artery (LCX). The specificity was 87%, 91%, and 100%, respectively. Even in those with three-vessel disease, a perfusion defect was seen in 82% of RCA and LAD segments, and 76% of LCX segment. Thus, there were high sensitivity and specificity for detecting individual coronary involvement by ECT imagings. Segmental analysis of ECT imagings was comparatively performed with the findings of contrast ventriculography. Normal wall motion was seen in 95% of normally perfused myocardial segments.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of coronary artery reperfusion on relation between creatine kinase-MB release and infarct size estimated by myocardial emission tomography with thallium-201 in man

The quantitative relations between serum creatine kinase-MB isoenzyme (CK-MB) release and the final infarct size estimated by myocardial emission computed tomography with thallium-201 was assessed in 37 patients with a first acute transmural myocardial infarction who underwent intracoronary thrombolysis using urokinase 4.6 +/- 1.9 hours after the onset of symptoms. Serial CK-MB determinations were used to calculate the accumulated release of CK-MB (sigma CK-MB). Myocardial emission tomography with thallium-201 was performed 4 weeks after the onset, and infarct volume was measured from reconstructed tomographic images by computerized planimetry. The results are presented for two groups of patients: 11 patients with unsuccessful thrombolysis (group A) and 26 patients with successful thrombolysis (group B). An excellent linear relation was found for group A (sigma CK-MB = 6.4 X infarct volume + 47.7, r = 0.91), whereas a different linear relation was observed for group B (sigma CK-MB = 10.5 X infarct volume + 89.1, r = 0.80). Moreover, serum CK-MB activity reached a peak at 21.1 +/- 2.2 hours after the onset in group A and reached an earlier peak at 12.5 +/- 2.9 hours in group B (p less than 0.001). These data suggest that acute coronary recanalization alters the kinetics of CK-MB release, resulting in greater CK-MB release into the serum for equivalent infarct volume estimated by myocardial emission tomography with thallium-201. Thus, serum CK-MB time-activity curves after acute myocardial infarction may be influenced considerably by acute reperfusion, which is an important factor that should be incorporated in the interpretation of enzymatic estimates of infarct size in human patients.

Collateral function in early acute myocardial infarction

The role of the collateral circulation less than 6 hours after the onset of acute myocardial infarction (MI) was evaluated in 34 consecutive patients without previous MI. There were 19 patients with and 15 without collaterals. The group was subdivided into those with nonjeopardized collaterals (group A, 14 patients) and those with jeopardized collaterals (group B, 5 patients), and the group without collaterals into those with partially obstructed coronary arteries (group C, 5 patients) and those with totally obstructed coronary arteries (group D, 10 patients). These groups had similar sites of coronary stenoses and MI. Eleven of 14 collaterals in group A were poor, but MI mass measured by peak creatine kinase (CK) was smaller in group A than in group B (p less than 0.01) or group D (p less than 0.01), and cardiac function was significantly better in group A than in group D (cardiac index, p less than 0.05; stroke index, p less than 0.01; ejection fraction, p less than 0.01; regional wall motion, p less than 0.01). Group C was not statistically different from group A in myocardial function and CK. Group B was similar to group D in MI mass and cardiac function (cardiac index, stroke index, ejection fraction and regional wall motion). Thus, patients with nonjeopardized collaterals and those with partially obstructed coronary arteries had less myocardial damage and better cardiac function than did those with jeopardized collaterals and those with totally obstructed coronary arteries. A nonjeopardized collateral circulation may play a role in limiting MI mass and preserving myocardial function in the early stages of acute MI.

[Evaluation of myocardial infarction by thallium emission computed tomography]

Thallium myocardial emission computed tomography (ECT) using a rotating gamma camera was undertaken to assess three-dimensional thallium distribution in the myocardium in cases with myocardial infarction (MI). Ninety-one cases with MI and 29 normal persons were examined by thallium ECT and the conventional planar imaging. Diagnostic performance and quantification of MI, and characterization of non-transmural MI were also investigated. In the detection of a perfusion defect, the ECT imaging showed significantly higher sensitivity (96%) than the planar imaging (77%) (p less than 0.001), especially in those with inferior wall MI (95% vs 73%, p less than 0.02) and nontransmural MI (82% vs 27%) (p less than 0.01). The specificity was the same in both techniques (90%), and therefore, higher overall accuracy was obtained by the ECT imaging (94%) than by the planar imaging (80%) (p less than 0.01). The receiver operating characteristic (ROC) curves were obtained from three independent observers for quantitative evaluation of observer detection performance. The ECT curves in each observer were situated in the upper left corner, indicating excellent diagnostic performance. Infarct size was estimated from the extent of the perfusion defect expressed as a percentage of the planar imaging (% defect) and as a volume of the infarcted myocardium (infarct volume). Those parameters were significantly correlated with peak CPK (r = 0.80 and 0.94, respectively), and inversely correlated with left ventricular ejection fraction (r = -0.78 and -0.85, respectively). Thus, the infarct volume calculated from the ECT is considered to permit estimation of infarct size more accurately than % defect from the planar imaging. To characterize nontransmural MI, 11 cases with nontransmural MI were examined by ECT and the findings were compared with those of transmural MI. A perfusion defect was detected in nine of the 11 patients (82%). As compared to those with transmural MI, infarct volume was smaller and the residual activity in an infarct region was higher in cases with nontransmural MI. Thus, the thallium ECT imaging, providing any-angle multisection of the myocardium, permits qualitative and quantitative evaluation of MI accurately.

Clinical application of ultrasound endoscope using linear array transducer for transesophageal ultrasonographic diagnosis of the disease of the mediastinum

Transesophageal ultrasound endoscopy by the linear array transducer built-in on top of the fiber optic gastroduodenoscope was applied for 13 clinical cases with various mediastinal lesions. It was quite valuable to diagnose mediastinal lesions such as lymphadenopathy in sarcoidosis, lymph node metastasis and direct invasion of lung cancer, dilatation of the diameter of the right pulmonary artery in pulmonary hypertension.

Estimation of infarct size by myocardial emission computed tomography with thallium-201 and its relation to creatine kinase-MB release after myocardial infarction in man

We evaluated emission computed tomography (ECT) for thallium-201 (201TI) myocardial imaging in estimating infarct size (IS). In 18 patients in whom IS was estimated enzymatically at the time of the acute episode, planar 201TI perfusion scintigraphy and ECT with a rotating gamma camera were performed 4 weeks after the first myocardial infarction. From the size of 201TI perfusion defects, the infarct area in planar images and the infarct volume in reconstructed ECT images were measured by computerized planimetry. When scintigraphic IS was compared with the accumulated creatine kinase-MB isoenzyme release (CK-MBr), infarct volume determined from ECT correlated closely with CK-MBr (r = 0.89), whereas infarct area measured from planar images correlated less satisfactorily with the enzymatic IS (for an average infarct area from three views, r = 0.69; for the largest infarct area, r = 0.73). Although conventional scintigraphic evaluation is useful for detecting and localizing infarction, quantification of ischemic injury with this two-dimensional technique has a significant inherent limitation. The ECT approach can provide a more accurate three-dimensional quantitative estimate of infarction, and can corroborate the enzymatic estimate of IS.

[Assessment of left ventricular function at rest and during exercise by gated cardiac blood pool scan and pressure measurement of the pulmonary artery by Swan-Ganz catheter]

Gated cardiac blood pool scan and hemodynamic parameters by Swan-Ganz catheter were simultaneously measured in five normal subjects (Group A), five patients with coronary artery disease (CAD) without angina on exercise (Group B) and nine patients with CAD with angina on exercise (Group C) in order to evaluate left ventricular function at rest and during supine bicycle ergometer exercise. Work load was gradually increased every 3 minutes and each data were acquired using a digital computer. There was a fairly good correlation (r = 0.83) between stroke volume by thermodilution method and stroke counts corrected by counts/ml of blood on gated cardiac blood pool scan, which were obtained by subtraction of end-systolic counts (ESC) from end-diastolic counts (EDC) in the region of interest arranged at the left ventricle. Stroke counts obtained by this method are considered to reflect a change in the left ventricular volume during exercise. As to the correlation between pulmonary capillary wedge pressure (PCWP) and stroke work index (SWI) at peak exercise, there was a large increase in SWI (78.9 +/- 17.6 to 112.3 +/- 30.0 g X m/m2) with a small rise in PCWP (10.0 +/- 1.9 to 16.2 +/- 4.0 mmHg) in Group A. In Group B, SWI was increased (57.8 +/- 15.8 to 92.9 +/- 25.2 g X m/m2) with a moderate rise in PCWP (11.8 +/- 3.7 to 20.0 +/- 3.1 mmHg) at peak exercise. In Group C, there was a trivial increase in SWI (74.0 +/- 16.0 to 81.2 +/- 29.3 g X m/m2) despite a marked rise in PCWP (13.1 +/- 3.1 to 33.4 +/- 8.9 mmHg). Similar relationship was present between SWI and EDC. On mild exercise of 25w, however, the rise in PCWP was more prominent rather than the increase in EDC in Group C. This indicates that the left ventricle in Group C is operating on a very steep portion of the diastolic pressure-volume curve.

Comparative study of thallium emission myocardial tomography with 180 degrees and 360 degrees data collection

Basic and clinical evaluation of thallium single-photon emission computed tomography (SPECT) using a rotating gamma camera with 180 degrees (LPO to RAO) data collection was carried out and compared with the full 360 degrees rotation. No attenuation correction was used. In a phantom study the reconstructed image from the 180 degrees scan revealed better resolution. Although the 180 degrees scan, when compared with the 360 degrees scan, showed great photon attenuation in the deep location of a line source in water, this problem was not significant in the clinical study of six normal hearts. In 11 cases with myocardial infarction, the perfusion defect was more clearly visualized in the 180 degrees scan. The defect-to-normal (D/N) wall-count ratio was lower in the 180 degrees scan (0.48 +/- 0.16; mean +/- s.d.) than in the 360 degrees scan (0.61 +/- 15, p less than 0.05), indicating superior lesion contrast in the former. These results suggest that for myocardial SPECT the 180 degrees collection method is a more effective technique in the clinical evaluation of coronary artery disease.

Ultrasonically guided aspiration needle biopsy in disease of the chest

Ultrasonically guided aspiration needle biopsy has been used in our department as a diagnostic procedure in chest disease. Twenty patients with chest disease judged to have lesions abutted to the thoracic wall were selected as candidates for this technique, which was a linear electronic array scanner provided with a specially designed guide channel. In all sixteen patients with malignant disease, this method provided biopsies that yielded malignant cells on cytologic examination. The diagnostic accuracy was excellent and no complications were encountered.

Cluster of mrdA and mrdB genes responsible for the rod shape and mecillinam sensitivity of Escherichia coli

Two closely linked genes, mrdA and mrdB, located at ca. 14.2 min on the Escherichia coli chromosomal linkage map, seen to be responsible for the normal rod shape and mecillinam sensitivity of E. coli. The product of mrdA was concluded to be penicillin-binding protein 2, because mrdA mutations caused formation of thermosensitive penicillin-binding protein 2. The product of the mrdB gene is unknown. At 42 degrees, C, mutation in either of these genes caused formation of spherical cells and mecillinam resistance. Both mutations was recessive, and complementation, as detected in +-/-+ meroheterodiploids having the wild-type phenotype, provided strong evidence that the two mutations are in different complementation groups. P1 transduction suggested that the most plausible gene order is leuS-mrdA-mrdB-lip. The rodA mutation reported previously seems to be similar to the mrdB murations, but the identities of the two have not yet been proven.

Ultrasonographic evaluation of ventilatory effect on inferior vena caval configuration

Ventilatory effect on inferior vena caval configuration was studied by ultrasonography in 14 subjects, including 5 with chronic obstructive pulmonary disease, 3 with cardiac tamponade due to carcinomatous pericardial effusion, one with tuberculous constrictive pericarditis, and 5 normal subjects. The inferior vena caval lumen decreased in the early inspiratory phase, reached a minimum at the end of inspiration, distended again during expiration, and closed transiently 2 to 3 cm below the diaphragm during maximal inspiration. These ventilatory changes of the inferior vena cava reversed with increase in intrathoracic pressure during the Valsalva maneuver and positive-pressure ventilation. When the central venous pressure was increased, as in cardiac tamponade, the inferior vena cava was fully distended through the entire phase of inspiration and expiration. Collapsibility of the inferior vena cava was inversely proportional to central venous pressure when the pressure was less than 10 cm H2O, but not when the pressure was greater than approximately 10 cm H2O. Our results suggest that the study of inferior vena caval configuration with ultrasonogrphy is a valuable noninvasive clinical aid for estimating central venous pressure and for analyzing inferior vena caval hemodynamics in various clinical conditions.

Mutational evidence for identity of penicillin-binding protein 5 in Escherichia coli with the major D-alanine carboxypeptidase IA activity

The defect in D-alanine carboxypeptidase IA activity in the dacA11191 mutant of Escherichia coli was correlated with a defect in the release of penicillin G from penicillin-binding protein 5. The results suggest that penicillin-binding protein 5 catalyzes the major D-alanine carboxypeptidase IA activity of the wild type and that the mutation results in a defect in the deacylation step catalyzed by this enzyme.

Enzymatic studies on the mechanism of action of cefoxitin. Correlation between the affinities of cefoxitin to penicillin-binding proteins and its rates of inhibition of the respective penicillin-sensitive reactions in E. coli

The affinities of cefoxitin, a cephamycin antibiotic, to penicillin-binding proteins of Escherichia coli were reexamined using a recently developed method for separating penicillin-binding proteins. The inhibitions by this antibiotic of four measurable penicillin-sensitive enzymatic reactions, the reactions of D-alanine carboxypeptidases IA and IB, cross-bridge formation and concomitant release of D-alanine, were also measured. An approximate correlation was found between the affinities of cefoxitin to the penicillin-binding proteins responsible for these reactions and its rates of inhibition of the respective penicillin-sensitive reactions.

New cephamycin antibiotic, CS-1170: binding affinity to penicillin-binding proteins and inhibition of peptidoglycan cross-linking reactions in Escherichia coli

The binding activity of CS-1170, a new cephamycin antibiotic, to penicillin-binding proteins (PBPs) in Escherichia coli and Proteus species and the potency of this antibiotic in vitro to inhibit enzymes involved in peptidoglycan cross-linking in E. coli were tested. Similar experiments were carried out with the 7alpha-H analog of CS-1170, R-45656, and the results were compared with those obtained with CS-1170. CS-1170 showed high affinities (compared with that of penicillin G) for E. coli PBP-1A, -1Bs, and -3, the PBPs of higher molecular weight, but not PBP-2. It also inhibited the in vitro peptidoglycan cross linking reaction and concomitant release of d-alanine at very low concentrations (approximately its minimal inhibitory concentration). This antibiotic also showed very high affinity for PBP-4, -5, and -6, the PBPs of lower molecular weight, and at extremely low concentrations it inhibited d-alanine carboxypeptidases IA and IB, corresponding to PBP-5/6 and PBP-4, respectively. CS-1170 seemed to be resistant to the beta-lactamase activity of PBP-5 and -6 in E. coli and Proteus species. R-45656 showed as high an affinity for PBP-1A, -1Bs, and -3 as CS-1170, but unlike CS-1170, it had low affinities for PBP-4, -5, and -6. The concentrations of R-45656 required for inhibition of d-alanine carboxypeptidases IA and IB were also much higher than those of CS-1170. R-45656 showed rather low activities in inhibiting the in vitro cross-linking reaction of peptidoglycan and concomitant release of d-alanine. Synergism was observed in 9 of 22 strains examined between CS-1170 and mecillinam, which bound specifically to PBP-2.

Isolation of a mutant of Escherichia coli lacking penicillin-sensitive D-alanine carboxypeptidase IA

A mutant of Escherichia coli that is deficient in D-alanine carboxypeptidase IA has been isolated. The enzyme is membrane bound and moderately sensitive to penicillin. It catalyzes in vitro both D-alanine carboxypeptidase and transpeptidase reactions. Being able to synthesize crosslinked peptidoglycan both in vivo and in vitro despite the absence of enzyme activity, the newly isolated mutant grew normally under a wide range of growth conditions. Therefore, this enzyme, like D-alanine carboxypeptidase IB, is not required for normal peptidoglycan synthesis in E. coli. The defect in the activity of D-alanine carboxypeptidase IA in the mutant however was not associated with disappearance of penicillin-binding proteins 5 and 6 (which have been shown to be D-alanine carboxypeptidase IA) or any of the other protein bands that bind [14C]penicillin G. Genetic mapping studies showed that the mutation (dacA) is located close to leuS(13.7 min) on the E. coli chromosome map. Double mutants (dacA dacB) that are deficient in both D-alanine carboxypeptidases IA and IB were obtained. These double mutants also were found to grow normally and to catalyze normal formation of crosslinked peptidoglycan.

Thermosensitive mutation in Escherichia coli simultaneously causing defects in penicillin-binding protein-1Bs and in enzyme activity for peptidoglycan synthesis in vitro

A thermosensitive mutant of Escherichia coli K-12 was isolated in which the membrane fractions were deficient both in penicillin-binding protein-1Bs, the major components of protein 1 [Spratt, B.G. & Pardee, A.B. (1975) Nature 254, 516-517] and in activity for in vitro peptidoglycan synthesis. The mutant was also supersensitive to many kinds of beta-lactam antibiotics. All these phenotypic changes were found to be caused by a single mutation (mrc). Genetic mapping studies show that the mrc mutation was located at about 3.3 min on the E. coli chromosome linkage map [Bachmann, B.J., Low, K.B. & Taylor, A.L. (1976) Bacteriol. Rev. 40, 116-167]. Penicillin-binding protein-1Bs seemed to be identical to one of the essential enzymes involved in crosslinking of peptidoglycan and the target of cell-lytic action of penicillins. Possible functions of some other penicillin-binding proteins in compensating for lack of protein-1Bs were also proposed.

Mutants of Escherichia coli lacking in highly penicillin-sensitive D-alanine carboxypeptidase activity

Mutants of Escherichia coli lacking in the highly penicillin-sensitive enzyme activities of D-carboxy-peptidase, transpeptidase, and endopeptidase, and with the concomitant absence of penicillin-binding protein 4 of B.G. Spratt and A.B. Pardee [(1975) Nature 254, 516-517] were isolated. The defect of these mutants is ascribed to the lack of an enzyme, D-alanine carboxypeptidase Ib. Genetic mapping studies show the mutation (dacB) to be located at 68 min on the E. coli chromosome map. The dacB mutation results in the simultaneous loss of D-alanine carboxypeptidase and penicillin-binding protein 4. The mutants grew normally under a wide range of growth conditions. We conclude that the enzyme is not a necessary component for normal peptidoglycan biosynthesis in E. coli.

Increase in sensitivity to antibiotics and lysozyme on deletion of lipopolysaccharides in Escherichia coli strains

Lipopolysaccharides on the cell surface of Escherichia coli prevent penetration of lysozyme or certain low-molecular-weight drugs.

Role of lipopolysaccharides in antibiotic resistance and bacteriophage adsorption of Escherichia coli K-12

Novobiocin-supersensitive (NS) mutants which could not grow on plates containing 40 mug or less of novobiocin per ml were isolated from Escherichia coli strain JE1011 (derived from E. coli K-12). Most of these NS mutants were found to have incomplete lipopolysaccharides (LPS), and they lack phosphate diester bridges in their backbone structure, with or without total loss of heptose, to which the phosphate diester is linked, and consequently lack external outer-core oligosaccharides. The phosphate diester bridges in the LPS backbone are apparently very important in forming a cell surface structure resistant to the penetration of antibiotics such as novobiocin, spiramycin, and actinomycin D. NS mutants, with incomplete LPS, lacking phosphates in their backbone structure were found to be resistant to phage T4, and those which also lacked heptose were resistant to phages T4 and T7. In contrast to the generally accepted idea that resistances to phages T3, T4, and T7 are linked genetically, no NS mutant was found to be resistant to T3. The possible structures of the receptors for T4 and T7 are discussed. The positions of novobiocin-supersensitive genes on the chromosome of several of the NS mutants defective in LPS were mapped. The genes were designated lpcA (between ara and lac) and lpcB (between 55 min and 60 min). The latter seemed to be a group of several related genes.