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Byline: Barbara L. Robinson, Terumasa Morita, Kunio Fujita, Matthew Chow, Hartzell V. Schaff, James J. Morris Abstract: Coronary vascular intraluminal release of endogenous endothelium-derived substances, such as prostacyclin, may affect downstream cardiac myocyte contractile function. With a 'chronic' canine model of endothelialized and deendothelialized internal thoracic artery coronary grafts, we tested the hypothesis that higher basal release of endothelium-derived prostacyclin in internal thoracic artery bypass conduit effluent accelerates functional recovery of postischemic stunned myocardium in the intact circulation. Eleven dogs underwent left internal thoracic artery-left circumflex artery bypass, and the proximal circumflex artery was then ligated. Internal thoracic artery conduit endothelium was denuded by balloon catheter in five dogs before grafting and left intact in six dogs. After 7 days, awake dogs were studied to measure myocardial segment length in the circumflex region with ultrasonic dimension transducers, left ventricular pressure with micromanometers, and circumflex artery flow with an ultrasonic flow probe. Regional contractile function was quantified by the area beneath the linear preload recruitable stroke work relationship at baseline and at intervals after a 15-minute circumflex graft occlusion followed by 3 hours of reperfusion. Heart rate, left ventricular peak pressure, left ventricular end-diastolic pressure, left ventricular peak first derivative of pressure (dP/dt), and circumflex flow were similar (all p not significant) in endothelialized and nonendothelialized dogs during ischemia and reperfusion. Ischemia reduced the preload recruitable stroke work relationship to 44% [+ or -] 35% of control values (p < 0.01) in endothelialized dogs and to 47% [+ or -] 18% of control values in nonendothelialized dogs (p < 0.01) at 15 minutes of reperfusion, indicating a similar (p not significant) initial degree of injury. During 3 hours of reperfusion, the preload recruitable stroke work relationship returned to 51% [+ or -] 17% of control values in endothelialized dogs but to only 35% [+ or -] 20% of control values in nonendothelialized dogs (p < 0.02). Basal intraluminal release of endogenous prostanoids in excised internal thoracic artery conduits was subsequently quantified by ex vivo bioassay of vasoactive properties of conduit effluent on normal coronary artery smooth muscle. Endothelialized conduits induced greater smooth muscle relaxation than did nonendothelialized conduits (67% vs 23%), and this increased relaxation by endothelialized conduits was eliminated by indomethacin, a blocker of prostanoid synthesis. These data indicate that coronary bypass conduit endothelium-derived substances, such as prostacyclin, significantly influence downstream myocardial contractile response to ischemia and reperfusion, independent of alterations in coronary flow in the intact circulation. (J T HORAC CARDIOVASC SURG 1996;111:62-73) Author Affiliation: Rochester, Minn. Article History: Received 2 November 1994; Accepted 12 April 1995 Article Note: (footnote) [star] From the Division of Thoracic and Cardiovascular Surgery, Mayo Clinic and Foundation, Rochester, Minn., [star][star] Address for reprints: James J. Morris, MD, Division of Thoracic and Cardiovascular Surgery, Mayo Clinic and Foundation, 200 1st St. S.W., Rochester, MN 55905., a 0022-5223/96 $5.00 + 0, aa 12/1/65967

Byline: Barbara L. Robinson, Terumasa Morita, David O. Toft, James J. Morris Abstract: In vitro studies suggest that interventions targeted at myocardial gene regulation of endogenous cytoprotective elements, such as heat-shock protein, may attenuate myocardial ischemic injury. We tested the hypothesis that heat shock-induced expression of myocardial heat-shock protein before ischemia accelerates functional recovery of postischemic stunned myocardium in the intact circulation. Sixteen dogs underwent partial femoral arteriovenous bypass and core temperature was raised to 42[degrees] C for 15 minutes in eight dogs (heat-shocked) and maintained at 37[degrees] C in eight dogs (nonheat-shocked). After 24 hours dogs were studied to measure myocardial segment length in the circumflex artery region with ultrasonic dimension transducers, left ventricular pressure with a micromanometer, and circumflex coronary flow with an ultrasonic probe. Regional contractile function was quantified by the area beneath the linear preload recruitable stroke work relationship at baseline and at intervals during reperfusion after a 15-minute circumflex artery occlusion followed by 3 hours of reperfusion. Baseline and peak reperfusion hyperemic circumflex flows were 37 [+ or -] 9 ml/min and 154 [+ or -] 33 ml/min, respectively, in heat-shocked dogs (p < 0.001) and 46 [+ or -] 24 ml/min and 171 [+ or -] 57 ml/min, respectively, in nonheat-shocked dogs (p < 0.001), with no differences between groups (p = not significant) at any time during reperfusion. Heart rate and left ventricular peak pressure, end-diastolic pressure, and first derivative of left ventricular pressure were similar (all p = not significant) in heat-shocked and nonheat-shocked dogs during ischemia and reperfusion. Before ischemia, preload recruitable stroke work relationship did not differ (p = not significant) in heat-shocked and nonheat-shocked dogs. Ischemia reduced preload recruitable stroke work relationship to 32% [+ or -] 8% control (p < 0.001) in heat-shocked dogs and to 19% [+ or -] 15% control in nonheat-shocked dogs (p < 0.001) at 15 minutes of reperfusion, indicating a similar (p = not significant) initial degree of injury. During 3 hours of reperfusion, preload recruitable stroke work relationship returned to 80% [+ or -] 38% control in heat-shocked dogs but to only 33% [+ or -] 13% control in nonheat-shocked dogs (p < 0.0001). Myocardial expression of heat-shock protein, quantified by optical densitometry of Western blots using an antibody specific for HSP70, was greater in heat-shocked than in nonheat-shocked dogs (108 [+ or -] 27 versus 71 [+ or -] 14 densitometry units, p < 0.005). Exact causal mechanisms remain to be defined, but these data indicate (1) hyperthermic bypass triggers induction of myocardial heat-shock protein and (2) elevated myocardial heat-shock protein is associated with accelerated recovery of stunned myocardium. Promotion of endogenous molecular cytoprotective systems represents a novel and potentially useful strategy for myocardial protection. (J THORAC CARDIOVASC SURG 1995;109:753-64) Author Affiliation: Rochester, Minn. Article Note: (footnote) [star] From the Division of Thoracic and Cardiovascular Surgery and the Department of Biochemistry and Molecular Biology, Mayo Clinic and Foundation, Rochester, Minn., [star][star] Read at the Twentieth Annual Meeting of The Western Thoracic Surgical Association, Olympic Valley, Calif., June 22-25, 1994., a Address for reprints: James J. Morris, MD, Division of Thoracic and Cardiovascular Surgery, Mayo Clinic and Foundation, 200 1st St. SW, Rochester, MN 55905., aa 0022-5223/95 $3.00 + 0, acents 12/6/62043

Summary: We analyzed total Ca handling of the left ventricle (LV) in the mildly failing heart preparation induced by a temporary intracoronary Ca overloading intervention in eight excised and cross-circulated canine hearts. This Ca intervention consisted of interruption of coronary blood perfusion by Ca-free oxygenated Tyrode perfusion for 10min followed by high-Ca (16 mmol/l) oxygenated Tyrode perfusion for 5 min. This intervention decreased the LV contractility index,E max (end-systolic maximum elastance), by 40% after restoration of the blood cross-circulation. We expected a Ca overload or paradox failing heart resembling the postischemic stunned heart and being characterized by an increased O2 cost ofE max. However, LV O2 consumption under mechanically unloading conditions decreased by 30% from control without increasing the O2 cost ofE max. To obtain a mechanistic view of this failing heart, we investigated cardiac total Ca handling by our integrative analysis method. In this method, we obtained the internal Ca recirculation fraction (RF) from the decay beat constant of the postextrasystolic potentiation following each sporadic spontaneous extrasystole in these failing LVs. We combined the RF with the decreasedE max and the unchanged O2 cost ofE max in our recently developed formula of total Ca handling. We found that these failing LVs had a slightly but significantly increased RF accompanied by either a slightly increased futile Ca cycling or a slightly decreased Ca reactivity ofE max, or both. Any of these three possible changes can account for the unchanged O2 cost ofE max. This result indicates that the present mildly failing heart has not yet fallen into a typical Ca overload or paradox by the temporary Ca overloading intervention.

A new type of fluorescence cytophotometer has been developed for multi-parameter cell analysis (Olympus BH2-QRFL). For multi-color fluorescence cytophotometry, this instrument is equipped with four sets of interchangeable filters, each consisting of an excitation filter, a dichroic mirror with a barrier filter, and a measuring filter. For permitting automatic operation of the filter sets, the cytophotometer is connected on line with a personal computer (HP 85F). A desired sequence of filter sets can be memorized in the software and multiple cellular constituents can be rapidly and consecutively determined on a single cell basis. All data are stored in the same computer and can be retrieved for further statistical analysis and display either in tabular form, or as histogram, correlation histograms, two-dimensional scatter plot, or two-dimensional frequency distribution histogram, on the CRT (cathode ray tube) with simultaneous hard copy. As an example of multiparameter cell analysis, combined protein and DNA measurements were performed on normal, border-line, and cancerous gynecological cytology specimens by using the ninhydrin-Schiff and Feulgen techniques.

An easy-to-construct, cost-effective, and versatile microspectrometric system, employing a circular variable filter as a continuous wavelength scan monochromator, is presented. This simple system includes a single microscope optics, a single photodetector, and a spinning glass plate in conjunction with signal processing electronics, which allows a variety of microspectrometric operations at the cellular level. Three modes of operation, such as double-beam, double-beam derivative, and single-beam wavelength modulated derivative, are provided by minor rearrangements of the optics and the electronic modules. Some spectra of living cells are also presented to demonstrate the system performance.

AbstractHere we report an infant with coronary artery fistulas. To clearly visualise the fistulas and surrounding materials, we utilised three-dimensional computed tomography, and the images were transferred as novel visualised three-dimensional images using a reconstruction technique. With the images, we could repair the fistulas accurately. We believe that these images are useful for repairing coronary artery fistulas in infants.