Joe D. Morris

Telencephalon of the teleost Macropodus: experimental localization of secondary olfactory areas and of components of the lateral forebrain bundle

Connections of the telencephalic hemisphere were experimentally examined to facilitate investigations of the functions of this major brain area in teleosts. The distribution of afferent olfactory tract fibers was traced using a degeneration method and autoradiographic localization of axonally transported protein. Afferents terminate predominantly ipsilaterally in the medial, lateral, and posterior zones of the hemisphere and in the nucleus posterior tuberis of the diencephalon. Afferents also project to the contralateral olfactory bulb through the commissure of Goldstein. The results of similar experiments in five other teleosts are briefly reviewed. Evidence of retrograde transport of tritiated proline or metabolite is also discussed. Components of the lateral forebrain bundle originating in the extreme rostral end of the dorsal zone of the hemisphere were traced to: (1) the corresponding zone of the contralateral hemisphere; (2) nucleus entopenduncularis; and (3) the extreme ventral part of the posterior zone of the diencephalon. The anatomical findings are discussed in relation to previous experiments in Macropodus dealing with the location of brain areas which concentrate sex steroids and with the effects of brain lesions on reproductive behavior in the male.

Measurement of pacemaker performance

Abstract Entirely satisfactory treatment of complete heart block has been prevented by an inability to measure pacemaker function after implantation. Two major problems can be identified in the long-term management of pacemaker patients: first, adequate prediction of when a pacemaker will fail; and second, accurate diagnosis of the type of pacemaker failure if it occurs. Observations on dogs gave precise measurements of interelectrode impedances. A method is described of externally measuring the interelectrode resistance and capacitance of implanted pacemakers. In studies on both dogs and human beings it was found that all changes in interelectrode impedance could be identified by changes in pacemaker rate and pulse width. Serial measurements of these two parameters allowed accurate diagnosis of the different types of “pacemaker failures.” The method also enabled anticipation of failures, other than wire breakage, before they were clinically evident. We think that pacemaker performance can be adequately evaluated by this method, making unnecessary prophylactic replacement of the unit.

Open Heart Surgery: Results in 600 Cases

The use of extracorporeal circulation during the surgical correction of heart lesions has become generally accepted. Comprehensive discussions of the problems of open heart surgery have been published (Clowes, 1960; Harley, 1960; Allen, 1958). A variety of methods and techniques have been developed for operating on the heart under direct vision, and those that are now in wide use achieve excellent results (DeWall and Lillehei, 1962; Drew, 1961; Gerbode, Osborn, and Johnston, 1960; Molloy, 1961). By the end of 1961 open heart operations for acquired and congenital cardiac lesions had been performed on 600 patients at the University of Michigan Medical Center. A safe, easily controlled procedure for maintaining extracorporeal circulation has been developed which is based on a rotating disc oxygenator and a means for inducing moderate systemic hypothermia. The programme of open heart surgery began in 1957 (Sloan, Morris, vander Woude, Hewitt, and Long, 1959), and the methods now in use represent development throughout the past four years. The risk in open heart surgery to-day is related almost entirely to the severity of the cardiac lesion rather than to the use of extracorporeal circulation. The mortality rate for correction of uncomplicated cardiac defects is less than 1 % in our hands.

Long-Term Results of Open Mitral Valvuloplasty

The long-term results of open mitral valvuloplasty in 51 patients are assessed. At the time of operation, 4 patients were in New York Heart Association Functional Class II, 41 in Functional Class III, and 5 in Functional Class IV. Group I (14 patients) had had previous closed mitral commissurotomy. Three patients died 2 to 4 years after open valvuloplasty. One patient died following valve replacement 7 years after the open valvuloplasty. Five others required mitral valve replacement 1 to 12 years following open valvuloplasty. Only 4 of the 14 patients are in Functional Class I or II 10 to 15 years following valvuloplasty. Group II (36 patients) had never undergone a previous mitral operation. Four of them died of progressive myocardial failure 4 to 6 years following valvuloplasty. One patient died of carcinoma of the lung 2 years postoperatively. Six patients underwent valve replacement 6 to 11 years following initial operation. Twenty-six have survived for at least 10 years without additional operation. Fourteen are in Functional Class I, and 12 are in Funcitonal Class II. Open mitral valvuloplasty allows for (1) accurate commissurotomy and careful subvalvular dissection, (2) direct vision to diagnose clot in the left atrial appendage or left atrium proper, (3) accurate assessment of residual or induced mitral regurgitation and immediate repair, and (4) reasonable operative mortality and morbidity.

Evacuation of Calcific Valvular Debris Using a Standard Ellik Evacuator

A simple but effective technique is described for removing calcific and other debris following aortic and mitral valve replacement. This technique uses an Ellik evacuator , which is readily available in most operating rooms. An 11-year experience is presented, documenting the efficacy of this method in several hospitals.

An Appraisal of the Double Indicator-Dilution Method for the Estimation of Mitral Regurgitation in Human Subjects

The amount of mitral regurgitation was estimated in 50 patients by an indicator-dilution technic and by the usual clinical, catheterization, operative, and autopsy criteria. There was a good correlation between the two estimates. Patients with significant mitral regurgitation (grade 2 or grade 3) had, with one exception, QR/QF ratios above 0.41. There were at least two instances where the calculated QR/QF was almost certainly falsely high. It seems likely that these discrepancies are related to the presence of an unusually large volume between the pulmonary artery and the femoral artery.