Selective stimulation of human T cells with streptococcal erythrogenic toxins A and B

Streptococcal exotoxins have been implicated in the pathogenesis of a toxic shock-like syndrome and scarlet fever. Previous studies have demonstrated that these toxins are potent stimulators of human T cells and have structural homology to staphylococcal enterotoxins. In the current study, we investigated the mechanism by which streptococcal erythrogenic toxins type A (SPEA) and B (SPEB) activate T cells and compared it with anti-CD3 and the known "superantigen" staphylococcal enterotoxin B. SPEA was found to selectively activate T cells bearing V beta 8, V beta 12, and V beta 14, whereas SPEB selectively activated T cells bearing V beta 2 and V beta 8. Furthermore, fibroblasts transfected with MHC class II molecules were capable of presenting SPEA and SPEB to purified T cells. The T cell response to these toxins, however, was not MHC-restricted. Although the streptococcal exotoxins stimulated both CD4+ and CD8+ T cells, SPEA but not SPEB stimulated the CD4+ T cell subset proportionately more than the CD8+ T cell subset. Our results indicate that SPEA and SPEB, like the staphylococcal enterotoxins, are superantigens and suggest a mechanism by which they may mediate particular systemic syndromes associated with streptococcal infections.

Light paired with serotonin in vivo produces both short- and long-term enhancement of generator potentials of identified B-photoreceptors in Hermissenda

An in vivo conditioning procedure consisting of light paired with the direct application of 5-HT to the exposed but otherwise intact nervous system of Hermissenda produces a long-term modification of phototactic behavior. The long-term change in phototactic behavior produced by in vivo conditioning is dependent upon pairing light with 5-HT. In this paper, we investigate neural correlates of in vivo conditioning detected in 2 different identified photoreceptors. We found that in vivo conditioning produces a short-term and long-term enhancement of light-evoked generator potentials recorded from medial and lateral B-photoreceptors. We show that short-term enhancement is not dependent upon pairing light with 5-HT, is observed in both lateral and medial B-photoreceptors, and is expressed by a larger peak and plateau phase of light-evoked generator potentials. In contrast to short-term enhancement, we found that long-term enhancement is dependent upon pairing light with 5-HT, is detected in only lateral B-photoreceptors, and is expressed by a larger steady-state plateau phase of light-evoked generator potentials. We also present evidence that the direct action of 5-HT interacting with light- and/or voltage-dependent processes is sufficient to mimic the effects of in vivo conditioning on long-term enhancement. These results suggest that long-term enhancement may contribute to modified phototactic behavior in Hermissenda produced by 1-trial in vivo conditioning.

Down-regulation of protein kinase C blocks 5-HT-induced enhancement in Hermissenda B photoreceptors

Light paired with serotonin (5-HT) in vivo produces both short and long-term enhancement of generator potentials in identified B-photoreceptors in Hermissenda. The contribution of protein kinase C to the induction of enhancement was assessed by pretreatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA), which produces a depletion or down-regulation of protein kinase C. Presentation of light and 5-HT after an 8 h pretreatment with TPA blocked the induction of enhancement of light-evoked generator potentials. Typical enhancement produced by light and 5-HT was observed after pretreatment with an inactive phorbol (4 alpha-phorbol). These results indicate that activation of protein kinase C is an important step in the induction of enhancement.

Inhibition of microvascular endothelial cell proliferation by vitreous following retinal scatter photocoagulation

Laser photocoagulation of pig retina induced breakdown of the blood-retinal barrier, with the appearance of serum proteins in the vitreous as determined by sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting techniques. Vitreous from lasered eyes inhibited the proliferation of cultured retinal microvascular endothelial cells in comparison with vitreous from non-lasered control eyes, and the inhibitory effect in the lasered eyes persisted for at least seven days. Inhibition was specific for endothelial cells, since no effect was observed when retinal pericytes or Tenon's fibroblasts were the target cells. These results suggest that indirect scatter photocoagulation may induce regression of neovascularisation by causing breakdown of the blood-retinal barrier and thus releasing into the vitreous serum components which result in inhibition of retinal microvascular endothelial cell growth.

Inhibition of protein synthesis blocks long-term enhancement of generator potentials produced by one-trial in vivo conditioning in Hermissenda

A one-trial in vivo conditioning procedure produces short- and long-term cellular changes that can be detected in identified sensory neurons of the pathway mediating the conditioned stimulus. The memory of the associative experience in the conditioned stimulus pathway is expressed by short- and long-term enhancement of light-evoked generator potentials recorded from identified lateral and medial type B photoreceptors within the eyes of Hermissenda. To identify mechanisms of the induction and expression of short- and long-term enhancement in identified photoreceptors, we have investigated the effects of inhibiting protein synthesis during the application of the one-trial in vivo conditioning procedure. Anisomycin (1 microM) present during and after the conditioning trial blocked long-term enhancement without affecting the induction or expression of short-term enhancement. Application of a control compound, deacetylanisomycin (1 microM), or delaying the application of anisomycin until 1 hr after the conditioning trial did not block either long- or short-term enhancement. These results indicate that synthesis of proteins during or shortly after training may be a critical step in the formation of long-term memory of the associative experience.

NIH3T3 transforming gene not a general feature of atherosclerotic plaque DNA (atherosclerosis/oncogene/NIH3T3 transfection assay)

A recent study indicated that the DNA isolated from human coronary atherosclerotic lesions is capable of transforming NIH3T3 cells in culture. Using DNA isolated from rabbit aortic and human carotid atherosclerotic lesions, we failed to observe such transforming activity. Thus, NIH3T3 transforming activity does not appear to be a general feature of atherosclerotic lesions.

[Digital thermo-coronary angiography--development and validation of the method in comparison with conventional cine-coronary angiography]

We describe the technique-thermal coronary angiography (TCA)-for real-time assessment of coronary anatomy and flow. The goal of this study was to compare thermal coronary angiography to cine coronary angiography and to validate its value for detecting stenoses. We studied the exposed LAD both in beating and arrested hearts in 11 open-chest pigs by TCA and cine angiography. We used an AGA 782 Thermovision system combined with a TIC 8000 digital image processor providing coronary images with 0.1-0.2 mm spatial and 0.1 degrees C thermal resolution, and a CFR x-ray system. The coronary arteries were catheterized via the right carotid artery, using standard 5F catheters. The thermal camera was focused at a 1m-distance to the heart surface and the x-ray was angled to LAO position. We performed simultaneous thermal and cine angiography using Angiovist 370 at different temperatures (10-40 degrees C) and injection rates (1-2.5 ml/s). Different grades of stenoses were created by snares. Thermistor probe readings of the epimyocardium and the left atrial blood were performed to reference the thermal camera measurements. We obtained high resolution TCA images of both the coronaries and of the myocardial perfusion beds whenever there was greater than 4 degrees C difference between injectate and epicardial temperature. The TCA detection of stenoses as compared to cine angiography was 29/30 (96.6%) in arrested and 36/42 (85.7%) in beating hearts. Coronary occlusion produced immediate and dramatic perfusion defects as detected by TCA. TCAs were highly reproducible. Injection rate of 2 ml/s provided optimal thermal coronary images. Thermal angiograms of the LAD were sometimes affected by large crossing coronary veins, myocardial bridges, and excess of fat pretending nonexistent coronary stenosis. TCA is a highly sensitive and reproducible method as compared to standard coronary angiography and allows for detection of coronary stenoses. The image quality was best in arrested hearts.

Thermal coronary angiography: a method for assessing graft patency and coronary anatomy in coronary bypass surgery

Thermal coronary angiography was evaluated in 50 patients undergoing 137 saphenous vein and 48 internal mammary artery bypass grafts. A total of 177 thermal coronary angiograms were performed after completion of the distal anastomoses by injection of cold cardioplegia into the vein or by reperfusion with warmer blood in the internal mammary artery grafts. These angiograms provided details of graft and anastomosis patency, flow directions, and presence of native coronary stenoses. Temperature differences between the injectant and the epimyocardium of greater than 4 degrees C resulted in high-contrast images. Thermal coronary angiograms were obtained in 173 of the 177 studied bypass grafts; 172 grafts were patent, and 1 internal mammary artery graft was occluded. Unsuspected stenoses were detected at the site of four distal anastomoses. Subsequently, two anastomoses were successfully revised and three additional grafts performed. Ninety-six native coronary stenoses were located in the recipient coronary arteries. In ten instances, the thermal coronary angiograms were obscured by excess fat or myocardium, thereby impeding correct image analysis. We conclude that thermal coronary angiography can be clinically relevant and helps improve decision making during coronary artery bypass operations.

Ultrasonic plaque ablation. A new method for recanalization of partially or totally occluded arteries

The potential application of ultrasonic energy for ablation of atherosclerotic plaques was studied in human atherosclerotic arteries with continuous and pulsed delivery of energy. With a prototype ultrasonic wire probe (n = 79 segments), there was gross reduction in vascular lesions as well as microscopic disruption of fibrous and calcified plaques. Normal portions of vessels appeared unaffected by the application of ultrasound. The prototype ultrasonic wire catheter ablated calcific deposits in less than 10 seconds. With this probe, all 26 complete atherosclerotic occlusions 0.5-5 cm in length were recanalized irrespective of the presence of calcium. Twenty-four of the segments were reopened in less than 20 seconds. By light microscopy, the site of plaque ablation was smooth, concave, and conformed to the shape of the probe tip. In 17 samples, there was evidence of thermal injury, and in six of the 79 samples studied with the prototype probe, there was vascular perforation. No vascular perforation occurred without thermal damage, when pulsed (rather than continuous) ultrasonic energy was used (n = 40) or when the duration of application was less than 30 seconds, with power output less than 25 W and with the probe oriented parallel to the wall (n = 26). Thus, by modifying the duration, mode, and magnitude of the ultrasonic power output, thermal injury and vascular perforation may be avoided. In vivo intra-arterial ultrasonic angioplasty of a canine chronic femoral fibrocellular occlusion was also performed. A preliminary in vivo study demonstrated feasibility of the percutaneous application of intra-arterial ultrasonic recanalization. Thus, ultrasonic energy appears to have potential as a method for ablation of occlusive atherosclerotic plaque.

B cell activation in patients with active procainamide induced lupus

Cellular immune abnormalities have been described in asymptomatic patients receiving procainamide therapy, but not in patients with active procainamide induced lupus. We tested patients with active procainamide lupus for evidence of T or B cell activation similar to that observed in idiopathic lupus. Symptomatic patients had a significant increase in spontaneous IgG synthesis, but T cells bearing activation markers were not significantly different from age matched controls. Our results demonstrate that patients with active procainamide lupus have evidence for B cell activation, similar to idiopathic lupus.

The effect of selective decontamination of the digestive tract with the addition of systemic cefotaxime on the aerobic faecal flora of mice

The administration per-orally to mice of the non-absorbable antibiotics polymyxin E, tobramycin and amphotericin B resulted in the elimination of detectable aerobic gram-negative rods from the faecal flora without affecting the total viable aerobic count. The addition of parental cefotaxime to the regime caused a fall in the number of aerobic lactobacilli and an increase in the number of enterococci. The rise was associated with the translocation of viable enterococci to the mesenteric lymph nodes and the spleen. The changes induced by cefotaxime were reversed when the antibiotic was withdrawn. Following withdrawal of all antibiotics the total aerobic faecal flora increased to above normal levels, but there was no associated diarrhoea. Attempts to implant exogenous enterobacteria into the digestive tract resulted in only low level colonization both in treated mice and in control mice. These results may have implications for the use of this antibiotic regime for selective decontamination of the digestive tract in humans, particularly those who are immunocompromised.

Intraoperative coronary angioscopy. Technique and results in the initial 58 patients

Coronary angioscopy provides images of intravascular detail with greater than 0.2 mm spatial resolution and excellent contrast resolution. Using endoscopes of 1.25 to 1.8 mm outer diameter, we performed intraoperative angioscopy of the coronary arteries or saphenous vein grafts, or both, in 58 patients. Eighty-one native coronary arteries and 43 vein grafts were examined. A clear viewing field was created by infusion of crystalloid cardioplegic solution through the aortic root during cardiopulmonary bypass. Technical details crucial for obtaining high-quality images were as follows: sufficient coronary perfusion by cardioplegic solution to displace all blood; adequate intraluminal illumination; and high-quality fiberoptic and lens systems. Incomplete studies in approximately 14% of patients were related to failure to achieve these technical details and lack of scope steerability. In 30% of patients, previously unrecognized anatomic details were revealed by angioscopy. These included intimal flaps at the site of vein-to-artery anastomoses, atheromatous plaques with adherent thrombi, and hemorrhagic ulcerated plaques, not recognized on angiography. Although a coronary intimal flap developed proximal to the anastomosis during retrograde examination in two patients, no serious complications occurred as a result of the procedure. We conclude that intraoperative angioscopy is safe, provides novel information that may be clinically relevant, and has future potential for development of the techniques for coronary endarterectomy and intraoperative balloon and laser angioplasty.

Light paired with serotonin mimics the effect of conditioning on phototactic behavior of Hermissenda

A conditioning procedure consisting of pairing-specific stimulation of the eyes and gravity-detecting statocysts in Hermissenda results in a long-term modification of normal positive phototactic behavior. The learning is expressed by a significant suppression of the initiation of locomotion in the presence of light. We now report that an analogue of the classical conditioning procedure, consisting of light paired with serotonin (5-HT) applied directly to the exposed circumesophageal nervous system of otherwise intact animals, mimics the effect of conditioning on long-term changes in phototactic behavior. The effect of the conditioning analogue on behavior shows some specificity with 5-HT since light paired with dopamine or octopamine does not significantly affect phototactic behavior. The conditioning analogue exhibits pairing specificity since unpaired light and 5-HT and 5-HT applied in the dark do not produce behavioral suppression. Animals that initially received unpaired light and 5-HT do show behavioral suppression after receiving paired light and 5-HT. These results indicate that light (the conditioned stimulus) paired with the putative transmitter of the unconditioned stimulus pathway (5-HT) is sufficient to produce long-term phototactic suppression.

Digital quantification eliminates intraobserver and interobserver variability in the evaluation of coronary artery stenosis

A leading problem with subjective interpretation of coronary angiography is high intraobserver and interobserver variability. Four experienced angiographers independently determined percent diameter narrowing of 36 stenoses using 3 methods: by subjective analysis of single-frame cine film images (film), by subjective analysis of digitized nonenhanced single-frame images (digital), and by using a semiautomated digital caliper quantification system (Corona). The reproducibility of interpretations was assessed by comparison of estimated intraclass correlation coefficients. Digital and Corona readings correlated well with subjective interpretation of film (r greater than 0.85 for both). In contrast to Corona, the angiographers systematically overestimated the magnitude of stenoses in the intermediate (50 to 75%) range. Corona markedly improved intraobserver (p less than 0.005) and interobserver (p less than 0.001) reproducibility. Corona less frequently misclassified individual observations than did film when categories of less than 50%, 50 to 75% and more than 75% diameter stenosis were used (3.7% vs 31.5%, p less than 0.001). Our results suggest that digitization of a coronary angiogram in a 512 X 512 matrix has no significant adverse effects on the perception and quantification of stenosis by angiographers. Additionally, automatic measurement of coronary stenosis has 2 major advantages: It is accurate compared with a group of experienced angiographers and for the practical purpose of clinical decision-making, it eliminates intraobserver and interobserver variability.

Pulsed ultraviolet lasers and the potential for safe laser angioplasty

Endoscopic laser ablation of atheroma using continuous wave lasers is limited by imprecise control of thermal ablation, resulting in a crater that expands in width and depth, with thermal damage to adjacent normal tissue. We compared the gross and histologic effects of pulsed 308 mm excimer irradiation to continuous-wave Nd:YAG and Argon Ion laser irradiation, and pulsed 1,060 nm, 532 nm, 355 nm, and 266 nm laser irradiation in 205 atherosclerotic aortic segments. In contrast to the continuous-wave Nd: YAG, Argon Ion, and pulsed 1,060 nm, 532 nm, and 355 nm laser irradiation, which produced gross and histologic evidence of uncontrolled ablation, the 308 nm and 266 nm pulsed lasers induced incisions that conformed precisely to the beam configuration without gross evidence of thermal injury. The incision edges from these two lasers were histologically smooth and comparable to a scalpel incision. Our histologic findings suggest that rapid, precise endoscopic ablation of vascular and nonvascular tissue can be performed at these shorter pulsed wavelengths with very high precision with relatively little damage or risk to adjacent tissue.

Alterable correlates of extrinsic and intrinsic job satisfaction at a state residential facility

A cross-section of employees at a state residential facility for mentally retarded persons was administered a composite questionnaire to assess factors associated with job satisfaction. Using a multivariate statistical approach, we examined two measures of job satisfaction (extrinsic and intrinsic) in relation to employee perceptions of organizational climate and selected job characteristics. Unique multiple regression analyses indicated that constraining conformity, decision frequency, and clarity of supervisor instructions were related to both measures of job satisfaction; organizational clarity, reward, and satisfaction with materials were related only to extrinsic satisfaction; and organizational standards and degree of resident contact were related only to intrinsic job satisfaction. Differences in variable contributions "ignoring" and controlling for other variables were emphasized. Variables were ranked according to their importance in predicting job satisfaction. Investigators are encouraged to consider the distinction between extrinsic and intrinsic job satisfaction in future research.

Variation in Indumentum Morphology in the Melaleuca leucadendra Complex (Myrtaceae)

A light and scanning electron microscope study of variation in leaf hairs in the Melaleuca leucadendra complex is described as a precursor to a taxonomic revision. The indumentum is homogeneous with respect to cellular structure, the hairs being simple, unicellular and unbranched. Hairs of different lengths are produced, with shorter hairs possibly produced later than the longer ones. The shorter hairs tend to be bent or crisped. There is diversity in the degree of crisping of short hairs which appears to be genetically based and this attribute is of some value as a diagnostic character. Two apparent geographical subspecies of M. nervosa are distinguished by differences in crisping of the shorter hairs. However similarities with hair patterns in other species suggest polyphylesis, and raise questions of natural relationships between entities within the M. leucadendra complex.

Comparison of upright and supine bicycle exercise in the detection and evaluation of extent of coronary artery disease by equilibrium radionuclide ventriculography

Upright and supine multiple gated cardiac blood pool scintigraphy was performed at rest and during maximum exercise in 37 patients, 15 with normal coronary arteriograms, 12 with coronary artery disease (CAD) without myocardial infarction (MI), and 10 with CAD and previous MI. Heart rate and systolic blood pressure were similar during upright and supine exercise in normal patients, but were significantly lower during supine exercise in both CAD groups. Left ventricular (LV) ejection fraction (EF), right ventricular (RV) EF, and LV segmental wall motion were similar in the upright and supine positions at rest or during maximum exercise within each group and showed high concordance of exercise responses. Although LV end-diastolic volume increased in all three groups during upright exercise and in both CAD groups when exercised supine, it did not change during supine exercise in patients without CAD. The fall of LV end-systolic volume in normals was greater during supine exercise than during upright exercise. LV end-systolic volume rose in the CAD patients in both positions. Therefore, although LVEF, RVEF, and LV segmental wall motion responses are similar in the upright and supine positions, LV end-systolic and LV end-diastolic volume changes are not. For detecting and evaluating CAD, the two different positions of exercise appear to have similar diagnostic content.

Analysis of regional ischemic left ventricular dysfunction by quantitative cineangiography

The ability of left ventricular angiography to detect regional ischemic dysfunction was assessed in 10 closed-chest dogs during the course of acute balloon occlusion of the anterior descending coronary artery. During the 2-minute period of occlusion, serial cineangiography revealed a sequence of wall motion abnormalities over the anteroapical region almost identical to that observed using directly implanted gauges. This sequence consisted of progressive reduction in regional systolic shortening with eventual replacement by systolic expansion. These changes preceded both electrocardiographic ST-segment and hemodynamic alterations, and were readily observed by gross subjective inspection of the cineangiograms, but with an intraobserver variability of 22%. Frame-by-frame motional analysis of the ventricular perimeter relative to its centroid of mass allowed more precise characterization of regional dysfunction. These data are consistent with previous studies demonstrating that regional wall motion abnormalities are both sensitive and specific markers of acute ischemia, and support the use of computerized left ventricular angiography for the quantitative assessment of clinical ischemic dysfunction.

Acute acetaminophen intoxication

Acetaminophen is a readily available, widely used drug which has been thought safer than aspirin. Overdosage which may result in fatal hepatic necrosis is commonly seen in the United Kingdom but is rarely reported in the United States. In a two-month period, three patients were admitted to a general hospital because of acetaminophen overdose, suggesting that this problem may occur more commonly than expected. They were successfully treated with N-acetylcysteine. Our experience in management of these three patients is presented and the pertinent literature concerning diagnosis and treatment of acute acetaminophen intoxication in briefly reviewed.

Involvement of the eye in SLE and scleroderma. A study using fluorescein angiography in addition to clinical ophthalmic assessment

General examination of the eye was carried out in 22 patients with systemic lupus erythematosus (SLE) and in 10 with scleroderma. 3 of the SLE and 2 of the scleroderma patients had keratoconjunctivitis sicca. Fluorescein angiography showed abnormalities of the retinal vasculature in one of a subgroup of 12 SLE patients and one of 10 scleroderma patients. None of the 12 SLE patients had abnormalities of the choroidal vasculature, while 5 of the 10 scleroderma patients had patchy areas of nonperfusion of the choroidal capillary bed.

Hemodynamic and metabolic responses to vasodilator therapy in acute myocardial infarction

Hemodynamic effects of vasodilator therapy (phentolamine or nitroprusside) were studied in 38 patients with acute myocardial infarction (AMI). Cardiac metabolism was studied in 19 of the 38 patients. According to the initial level of left ventricular filling pressure (LVFP) and left ventricular stroke work index (SWI), patients were divided into three groups: Group I-nine pa- tients with LVFP 15 mm Hg or less; Group II-14 patients with LVFP > 15 mm Hg and SWI >20 g-m/m 2 ; Group III-15 patients with LVFP > 15 mm Hg and SWI < 20 g-m/ m 2 . In Group I most patients were clinically uncomplicated. In Group IL most patients had clinical left ventricular failure including one patient who had clinical features of cardiogenic shock. Group III patients all had severe left ventricular failure, with eight patients in clinical shock.

In all groups LVFP, pulmonary artery pressure, right atrial pressure, and systemic and pulmonary vascular resistance decreased significantly with vasodilator therapy with only a slight to moderate decrease in arterial pressure. In Group I patients SVI decreased (-7%) together with an increase in heart rate. Significant improvement in left ventricular performance, however, was observed in Groups II and III as indicated by increased stroke volume index (SVI) and cardiac index (CI) and decreased LVFP. The increase in SVI and CI was of similar magnitude in both Group LI (SVI +18%, CI +24%) and Group III (SVI +28%, CI +29%) patients, a change suggesting that vasodilation thereby may be applicable and beneficial even in the presence of severe depression of cardiac performance.

Improved left ventricular performance in group II and III patients was accompanied by a slight decrease in coronary blood flow, myocardial oxygen consumption, and transmyocardial oxygen extraction. There was no change in myocardial lactate metabolism in any group. In vitro studies in isolated cat papillary muscle preparations showed no direct positive inotropic effect of either phentolamine or nitroprusside. Thus, significant improvement in left ventricular performance occurs during vasodilator therapy in patients with AMI and elevated LVFP, even in the presence of severe depression of cardiac performance. Furthermore, this improvement is not accompanied by increased metabolic cost. Vasodilator therapy, therefore, may have an important role in the treatment of pump failure complicating myocardial infarction.

Beneficial effects of vasodilator agents in severe mitral regurgitation due to dysfunction of subvalvar apparatus

To assess the potential beneficial effects of vasodilator agents in patients with severe mitral regurgitation, sodium nitroprusside was administered intravenously at a rate of 16 to 100 µg/min in eight patients with clinically significant mitral regurgitation presumably due to dysfunction of the subvalvar apparatus. In all patients there was a decrease in the magnitude of the peak `V' wave (from 50 ± 4.5 to 19 ± 2.9 mm Hg) and in left ventricular filling pressure (33 ± 1.8 to 16 ± 1.4 mm Hg), together with a decreased intensity of the apical pansystolic murmur. There was a significant increase in forward cardiac index (2.2 ± 3.5 to 3.3 ± .47 liter/min/M 2 ) and forward stroke volume index (23 ± 4.4 to 36 ± 6.6 ml/M 2 ) along with a reduction in systemic vascular resistance (1802 ± 331 to 1102 ± 241 dynes/sec/cm -5 ). In the five patients in whom the therapy was continued, relief of symptoms of pulmonary venous congestion occurred. In the four patients in whom left ventricular volumes were determined angiographically, the observed increase in forward stroke volume was due to a reduction in the regurgitant fraction. These findings suggest that the use of vasodilator agents like nitroprusside can achieve the major objectives of treatment of patients with mitral regurgitation: an increase in forward stroke output, a reduction in regurgitant volume and a decrease in pulmonary venous pressure.

Catheterization of left ventricle in acutely ill patients

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