Quantification of the Whole Lymph Node Vasculature Based on Tomography of the Vessel Corrosion Casts.

Lymph nodes (LN) are crucial for immune function, and comprise an important interface between the blood and lymphatic systems. Blood vessels (BV) in LN are highly specialized, featuring high endothelial venules across which most of the resident lymphocytes crossed. Previous measurements of overall lymph and BV flow rates demonstrated that fluid also crosses BV walls, and that this is important for immune function. However, the spatial distribution of the BV in LN has not been quantified to the degree necessary to analyse the distribution of transmural fluid movement. In this study, we seek to quantify the spatial localization of LNBV, and to predict fluid movement across BV walls. MicroCT imaging of murine popliteal LN showed that capillaries were responsible for approximately 75% of the BV wall surface area, and that this was mostly distributed around the periphery of the node. We then modelled blood flow through the BV to obtain spatially resolved hydrostatic pressures, which were then combined with Starling's law to predict transmural flow. Much of the total 10 nL/min transmural flow (under normal conditions) was concentrated in the periphery, corresponding closely with surface area distribution. These results provide important insights into the inner workings of LN, and provide a basis for further exploration of the role of LN flow patterns in normal and pathological functions.

Dosimetric characteristics of 192Ir sources used in interstitial brachytherapy.

Dosimetric quantities of 192Ir seed (5 mm length) and wire (10 mm length) brachytherapy sources have been determined. The quantities were measured based on the protocol introduced by the Radiation Therapy Committee of the American Association of Physicists in Medicine (AAPM) Task Group 43. Quantities such as dose rate constant, (lambda), radial dose function, g(r), and anisotropy function, F(r, theta) were experimentally determined and the geometry function, G(r, theta), was calculated. TLD measurements were made in a polymethyl methacrylate (PMMA) phantom of dimensions 25 cm x 20 cm x 5 cm by means of LiF:Mg,Ti (TLD-100) dosimeters for distances of 1-10 cm for g(r), and the same distances at angles of 0-180 degrees for F(r, theta). Dose rate constant for 192Ir seed and wire were found to be 1.196+/-5 and 1.082+/-5% cGy h(-1) U(-1), respectively (1 U = unit of air Kerma strength = 1 microGy m2 h(-1) = 1 cGy cm2 h(-1)). The obtained results for g(r), G(r, theta) and F(r, theta) are also presented and discussed.

His bundle electrocardiography in manifest and concealed right bundle branch extrasystoles.

His bundle electrocardiography was helpful in the diagnosis of impulse formation in the right bundle branch. Ten patients with narrow QRS complexes had ectopic beats with an "incomplete" left bundle branch pattern and almost simultaneous activation of His bundle and ventricles. Both QRS morphology and H- - V intervals depended on the more proximal or distal location of the ectopic focus. In four patients with "complete" right bundle branch block the morphology of ectopic ventricular complexes and H- - V intervals also depeneded on the presence or absence of retrograde block and differential degrees of forward and/or retrograde conduction delays. Nine patients with "complete" right bundle branch block and four with "complete" left bundle branch block had premature beats which could have originated in the proximal right bundle branch, proximal left bundle branch, or distal His bundle. In one patient with "complete" left bundle branch block, "concealed" His bundle depolarizations (probably originating in an ectopic focus located in the right bundle branch) produced pseudo Type II (Mobitz) A-V block. Although lidocaine appeared to have been more effective in patients with bundle branch block than in those with narrow QRS complexes, further studies are necessary to corroborate this impression.

Clinical and hemodynamic criteria for use of the intra-aortic balloon pump in patients requiring cardiac surgery.

In order to establish criteria for elective use of the intra-aortic balloon pump (IABP) in patients having cardiac surgery, we conducted a retrospective study of 43 patients who required counterpulsation, because of inability to be weaned from cardiopulmonary bypass, between May, 1972, and June, 1974. Patients in cardiogenic shock preoperatively were excluded. The 43 patients included 23 (Group A) who had severe preoperative left ventricular dysfunction with a mean cardiac index less than 1.8 L. per minute per square meter, ejection fraction less than 30 per cent, and end-diastolic pressure greater than 22 mm. Hg; 20 patients (Group B) had a combination of moderate cardiac dysfunction (cardiac index less than 2.2, ejection fraction less than 40, end-diastolic pressure less than 18) in the presence of acute infarction or severe aortic stenosis (gradient greater than 80 mm. Hg) with or without coronary disease. An inverse relationship was noted between survival and delay from completion of operation to the use of 1ABP. Thirty-two of 43 patients were weaned off bypass and were balloon assisted for 12 to 96 hours postoperatively; 25 patients were discharged (58 per cent). In Subgroup A, 14 of 23 (60 per cent) and, in Subgroup B, 9 of 20 (45 per cent) were long-term survivors. Based on these findings, 45 patients were operated upon between June, 1974, and December, 1975, with elective use of 1ABP and were assessed by serial hemodynamic studies. Sixteen had severe preoperative left ventricular dysfunction similar to Subgroup A and 29 had moderate dysfunction in combination with pathology similar to Subgroup B. Fifteen of these patients were hemodynamically unstable at time of arrival in the operating room; 1ABP was inserted under local anesthesia. Thirty-nine patients (87 per cent) were weaned off bypass and were hospital survivors. In Subgroup A, 13 of 16 (81 per cent) and, in Group B, 21 of 29 (72 per cent) were long-term survivors. Criteria for elective use of 1ABP in cardiac surgery should include severe preoperative left ventricular dysfunction or a combination of moderate dysfunction with coronary or valvular pathology. Elective 1ABP improves the survival with trivial iatrogenic morbidity.

The retrograde His bundle deflection: its recognition and value in the analysis of tachyarrhythmias induced by stimulation on the T wave.

Interpretation of deflections presumably retrograde His bundle in origin has to be performed in context considering the coexisting changes in simultaneously recorded intracardiac and surface leads. His bundle electrocardiography thus conceived is helpful in the analysis of the runs of ectopic beats elicited by premature ventricular stimulation during the antecedent T wave in patients without coronary artery or primary myocardial disease. Identification of AV nodal echoes within the paroxysms as well as the subsequent runs of reciprocating tachycardias, was possible in patients with and without preexcitation, although a thorough study of these cases also requires recording of coronary sinus and low lateral right atrial electrograms. The behavior of the retrograde H deflection in respect to the first extra beat following the premature QRS complex helped in excluding bundle branch reentry. The latter is improbable in patients with 'complete' bundle branch block pattern, if extra beats show a contralateral bundle branch morphology. However, in absence of bundle branch block, retrograde H deflections were not helpful in elucidating the mechanisms of pacemaker-induced intraventricular (bundle branch, fasicular or vulnerability-related) reentry.

Role of coronary artery surgery in patients surviving unexpected cardiac arrest.

During the past 3-1/2 years, 101 of 199 patients who were successfully resuscitated by fire rescue squads in the community after unexpected cardiac arrest (documented ventricular fibrillation--VF) were admitted to the hospital. Forty-two of these patients ultimately were discharged from the hospital. However, the intermediate and long-term results were disappointing, for their mean survival after discharge was only 12.7 months. Sudden deaths (recurrent unexpected VF) occurred during the first 12 months after discharge in 28 percent of the patients surviving the initial hospitalization. Among the survivors of sudden and unexpected VF (i.e., survivors of the initial hospitalization), 16 patients who had had pre-existing symptoms of coronary heart disease had hemodynamic and coronary angiographic studies. Of these, 11 were considered surgical candidates. This report concerns the follow-up results in these patients with particular emphasis on the eight patients who accepted surgery and had myocardial revascularization. Five patients had moderate hemodynamic abnormalities, but none had had an acute myocardial infarction at the time of the initial arrest. The group of eight patients had a total of 18 vein graft bypasses performed. The significant findings is that all eight survived operation, and there was one late death at 10 months. The remaining patients are alive at 14 to 34 months, and six are free of symptoms. Despite patent vein grafts, one patient has had a second serious arrhythmia. It is concluded that surgical intervention can be done safely and may decrease the high posthospitalization, recurrent arrest, and mortality rates in selected survivors of unexpected cardiac arrest. It is concluded further that all patients sustaining an unexpected arrest should have postarrest coronary catheterization and angiography, and all patients should be on antiarrhythmic agents whether or not they receive myocardial revascularization.

Coronary revascularization in patients surviving unexpected ventricular fibrillation.

Coronary angiography and hemodynamic studies were performed in a group of 13 patients who had been successfully resuscitated from unexpected ventricular fibrillation, had had angina pectoris prior to the cardiac arrest, and who had not had an acute myocardial infarction in the periarrest period. Eleven of the 13 had one or more coronary artery lesions which were amenable to surgical intervention, and eight of the 11 accepted surgery. Left ventricular end-diastolic pressure was elevated in most patients, while cardiac index and ejection fraction were depressed. Bypassable lesions were found in the main left coronary artery in one patient, and the proximal left anterior descending artery in two. Both of these patients had disease elsewhere. The remaining five patients had diffuse three-vessel disease. The eight patients have survived for periods ranging from 8 to 32 months (average = 24 months). This contrasts to an overall 1-year mortality of approximately 30% in survivors of hospitalization after unexpected ventricular fibrillation.

Left main coronary artery obstruction. Follow-up of thirty patients with and without surgery.

Thirty patients, 20 males and 10 females, having a 50% or greater obstruction of the left main coronary artery, were evaluated. Their ages ranged from 40 to 71 years (mean 53.8 years). All patients had angina pectoris, the duration of which varied from 2 months to 20 years (mean 5.4 years). Twenty-four patients (80%) had accelerated angina pectoris; 17 (56.7%) had prior myocardial infarction, and 27 (90%) were found to have coexisting three-vessel disease and abnormal left ventricular contraction. There were no deaths or serious arrhythmias related to cardiac catheterization procedures. In the 11 unoperated patients 5 (45%) died within the first year of follow-up; however, all except one death occurred in patients with diffuse distal coronary artery disease technically unsuitable for surgery. Among the six survivors four were considered surgical candidates. These four patients have continued to have symptoms of angina pectoris with a mean follow-up period of 17.5 months (16 to 20 months). In the 19 patients who underwent aortocoronary saphenous vein bypass grafting, there was one immediate postoperative death (surgical mortality 5.3%) and one late death. The 17 survivors in the surgical group have a mean follow-up period of 17.3 months (8 to 31 months); 13 of them have clinically improved with 6 being totally free of angina pectoris. Thus, mortality is extremely high in those with poor distal vasculature technically unsuitable for surgery, but mortality is relatively low in patients who have technically bypassable lesions whether treated surgically or medically. Although saphenous vein bypass grafting appears to be more effective in providing clinical improvement, asymptomatic left main coronary obstruction may not justify surgical therapy.

A wandering bullet. Successful removal and a simple technique to prevent its migration.

Bullet migration toward and within the pulmonary circulation occurred in a case of gunshot wound to the right upper abdominal quadrant. Difficulties in locating the missile were encountered during surgical attempts to remove it. Finally, a Swan-Ganz catheter was used for pulmonary angiography. The balloon of the catheter was inflated to prevent further migration of the missile until it could be surgically removed.

Bullet embolization to the heart. Report of a case and review of the literature on indications for removal of intracardiac foreign bodies.

The hospital course of a young man with a bullet migration through the venous system to the right ventricle is reviewed. The intraoperative management of foreign bodies to the heart using x-ray image intensifier is employed.

Results of direct coronary artery surgery in women.

In the past 4 years, among 260 patients receiving coronary bypass grafts for coronary artery disease and stable angina pectoris, there were 34 women (13 per cent). The operative mortality rate for women was 8 per cent (3 of 34), and one late death due to myocardial infarction occurred in spite of a patent coronary bypass graft. The intraoperative infarction rate was 20 per cent (6 per cent in men). Although preoperative cardiac pump and muscle function parameters were better in women than in men (p less than 0.05), postoperatively only 30 per cent of women showed improvement in function as compared with 50 per cent of men. At 6 to 46 months' follow-up, 84 per cent of women were free of angina in contrast with 94 per cent of men. The early (4 month) graft patency rate was 50 per cent (14 of 27 grafts), as opposed to 80 per cent (20 of 25 grafts) in men. These results indicate that, although coronary artery disease shows anatomic similarity in women and men, the result of coronary revascularization in women is inferior to that in the male population.

Hemodynamic features of prolapsing and nonprolapsing left atrial myxoma.

In the course of the evaluation of five patients with left atrial myxoma, it was noted that the movement of the myxoma was related to specific changes in left atrial hemodynamics. Prolapsing tumors, Type I, move from the left ventricle to the left atrium in early systole and from the left atrium to the left ventricle in early diastole, thereby causing prominent c and v waves accompanied by a rapid y descent. Nonprolapsing tumors, Type II, remain in the left atrium during the entire cardiac cycle, impeding flow across the mitral valve. In these latter cases, the y descent is slow and indistinguishable from that caused by mitral valvular stenosis. The cineangiocardiograms and echocardiograms corroborate these two types of hemodynamic observations. The particular value of direct echocardiographic examination of the left atrium prior to cardiac catheterization was evident in two of the three patients with nonprolapsing tumors. Since the hemodynamic pattern of nonprolapsing left atrial myxoma resembles that of mitral valvular stenosis, it is stressed that echocardiography should have an important place in precatheterization assessment of patients with mitral valve disease. If left atrial myxoma is suspected clinically or on the basis of echocardiographic findings, regardless of the pressure curve contours, transseptal cardiac catheterization should be avoided and the left atrium visualized by pulmonary angiography levophase.