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We tested the hypothesis that the mechanical workload of the heart inversely determines the rate of myocardial edema formation in an isolated, perfused rat heart preparation. Heart rate (HR) was varied in three groups by pacing at 125 (HR125), 250 (HR250), or 350 beats/min (HR350). Left ventricular pressure (LVP) was varied in two additional groups by pacing at 250 beats/min and with the addition of either epinephrine (Epi) or propranolol (Pro) to the perfusate. In five otherwise identical groups, variation of coronary vascular resistance was minimized by adenosine. Myocardial water content (MWC) varied significantly and inversely with HR in the HR125, HR250, and HR350 groups. MWC of the HR250 group was significantly less than that of the Pro group but did not differ from the Epi group. However, when adenosine was used, MWC had significant inverse relationships with HR and LVP. We concluded that the mechanical workload of the heart inversely determines the rate and degree of myocardial edema formation in this isolated heart preparation, and both HR and LVP are determinants of this relationship.

Objectives: We performed the following study to define the effects of acute cardiac lymphatic obstruction on left ventricular (LV) systolic and diastolic function. Methods: Cardiac lymphatic obstruction was created in 8 pentobarbital-anesthetized dogs by identifying (Evans blue) and ligating the right and left epicardial lymphatics, the afferent and efferent lymphatics associated with the pretrachael and cardiac lymph nodes, and the thoracic duct. Left ventricular function was assessed by analysis of micromanometer-conductance catheter-derived LV pressure-volume relationships. Contractility was assessed by preload recruitable stroke work (PRSW). The active and passive phases of LV relaxation were assessed by the time constant of isovolumic relaxation (τ) and the end-diastolic pressure-volume relationship (stiffness), respectively. Results: PRSW decreased significantly and τ increased significantly from baseline at 1, 2, and 3 h after cardiac lymphatic obstruction ( n = 8), but stiffness did not change. Cardiac lymphatic obstruction had similar effects on LV function in a group of autonomically blocked dogs ( n = 5). Left ventricular function did not change in sham treated controls ( n = 8). Cardiac lymphatic obstruction induced a significant increase in LV wet/dry weight ratios (3.58 ± 0.01) when compared to the control group (3.53 ± 0.02). Histophatology of the myocardium in the lymphatic obstruction groups revealed significant lymphangiectasis and increased interstitial spacing when compared to controls. Conclusions: Acute cardiac lymphatic obstruction depresses contractility and active relaxation and causes mild LV myocardial edema, but does not alter diastolic stiffness.

Two of nine female opossums (Didelphis virginiana) in a closed breeding colony were submitted for necropsy due to a history of poor reproductive performance in the absence of overt clinical disease. On histologic examination, marked granulomatous to pyogranulomatous pneumonia was identified in these animals.Lung sections were stained with periodic acid-Schiff and Gomori's methenamine silver nitrate.Pulmonary lesions were characterized by large numbers of foamy macrophages within the alveoli and interstitium, prominent subpleural and peribronchiolar aggregates of histiocytes, and a few scattered lymphoid nodules. Numerous fungal organisms were evident within the cytoplasm of macrophages on impregnation of histologic sections with the aforementioned stains. Other inciting agents were not identified. A third opossum lacked pulmonary lesions, but had similar organisms within one auricular sebaceous gland/hair follicle without apparent reaction to the organisms.A fungal agent was associated with granulomatous pneumonia in the opossum, and comparison was made with endogenous lipid pneumonia previously described in opossums. These findings stress the importance of use of special stains and additional diagnostic techniques when prominent alveolar macrophage accumulation is present on histologic examination of the opossum lung.

This study was performed to evaluate the direct and indirect effects of acute coronary sinus hypertension (CSH) on systolic and diastolic left ventricular (LV) function. Coronary sinus pressure was elevated to 25 mmHg for 3 h in eight pentobarbital-anesthetized dogs and then relieved. LV contractility was assessed by preload recruitable stroke work (PRSW) and end-systolic elastance (Ees). Diastolic function was assessed by the time constant of isovolumic relaxation (tau) and the end-diastolic pressure volume relationship (EDPVR). PRSW and Ees decreased progressively, and tau and the slope of the EDPVR increased progressively with CSH. These changes persisted after relief of CSH. beta-Adrenergic and cholinergic receptor blockade, performed in six dogs, did not alter the effects of CSH on systolic or diastolic function. The LV wet-to-dry weight ratios of the groups with CSH were significantly greater than those of a control group without CSH. We conclude that CSH results in changes in the left ventricle that depress contractility, prolong active relaxation, and increase diastolic stiffness. The dysfunction was not the direct effect of CSH or autonomic reflex activation, but may have been induced by fluid accumulation within the interstitium.

Thin film Auger electron analysis of gold films on nickel was performed while simultaneously sputtering with argon ions. The influence of film thickness, electron and ion beam energies, ion beam current density and initial surface roughness on depth resolution was investigated. The intrinsic limitations of depth resolution result from the escape depth of Auger electrons and from atomic mixing due to ion impact. Prolonged ion sputtering leads to the development of microroughness. The influence of this last effect is described by an empirical correlation which shows the width of the transition region to increase with the square root of the product of ion beam energy and film thickness. The original surface roughness also affects depth resolution but, at higher ion beam energies (2 keV) in particular, its influence is somewhat masked by ion-induced microroughness. Optimum resolution (5% of film thickness) in depth profiling is obtained by employing well-polished samples and low ion beam energies.

A compensating automatic ellipsometer that employs Faraday rotators has been constructed. Speed of response and resolution superior to that of any similar instrument now in use have been achieved through novel Faraday solenoid designs, modulation with high frequency and large amplitude, and refinements in circuitry.

A series of tricyclic oxazines, namely, the 4-substituted 2H-naphth[1,2-b]-1,4-oxazines, have been synthesized and assayed for dopamine agonist activity. One of the members of this series, compound (+)VII-15, was found to be a remarkably potent agonist in vivo when tested in the standard 6-hydroxydopamine lesioned rat assay. The absolute configuration of the compound corresponds to that found in the active isomer of apomorphine. Its activity at the alpha 2 receptor (vs. [3H]clonidine) is relatively low. It also failed to stimulate the synthesis of cAMP in the carp retina assay, thus giving the compound a highly selective profile in favor of the D2 receptor.

We hypothesized that the apparent difference in base-line lymph-to-plasma protein concentration ratios (L/P) between acutely and chronically prepared sheep is due to an underlying difference in pulmonary microvascular permeability. Therefore, we sought to determine the pulmonary microvascular osmotic reflection coefficient for acutely prepared sheep, in a manner similar to that used by Parker et al. (Circ. Res. 49: 1164–1172, 1981) in chronically prepared animals. In 20 acutely prepared sheep, we evaluated pulmonary lymph flow (QL) and L/P as left atrial pressure was progressively elevated. As a result of the elevated hydrostatic pressure, QL increased by 28 to 773% above base-line flows, accompanied by substantial dilution of lymphatic protein. At high QL, L/P approached a minimal value, (L/P)min, of 0.39. The osmotic reflection coefficient (sigma d), calculated as sigma d = 1 - (L/P)min, was 0.61, substantially lower than the value of 0.74 found by Parker et al. in chronically prepared sheep. We conclude that the higher base-line L/P found in acutely prepared sheep is due to higher pulmonary microvascular permeability, possibly the result of the more immediate surgical trauma.

Auger spectra of TiO2,Ti2O3, TiO, and Ti were determined as a function of sputter time to study ion‐beam and electron‐beam effects in AES depth profile analysis of titanium oxides. The value of the oxygen–titanium peak amplitude ratio for a given titanium oxide depends on ion‐beam energy, electron‐beam current density, and oxide composition. Both ion and electron beam give rise to an apparent reduction effect and their combined action stimulates the formation of carbide at the sample surface. The latter effect is more pronounced at an ion‐beam energy of 0.5 keV than at 2 keV. Depth resolution characterized by the width of the transition region between oxide and metal decreases with increasing ion‐beam energy and with increasing thickness of the sputtered layer.

Efferent lymph collected from the caudal mediastinal lymph node (CMN) in the sheep lung lymph fistula model has been reported to represent free pulmonary interstitial fluid. Studies that utilize this model assume that nodal transit does not alter the composition of lymph. We collected afferent lymph from the tracheobronchial node (TBN) while simultaneously collecting CMN efferent lymph in acutely prepared sheep. We compared afferent and efferent lymph protein concentrations (CA and CE) and changes in flow rates (QLA and QLE) during base line and periods of elevated left atrial pressure (Pla). As a result of elevated Pla, QLA and QLE increased and the afferent lymph-to-plasma protein concentration ratio (CA/Cp) and the efferent lymph-to-plasma protein concentration ratio (CE/Cp) fell. The CA/Cp was significantly lower than the CE/Cp during base line (0.67 vs. 0.80) and periods of elevated Pla (0.41 vs. 0.61). Although we cannot exclude regional permeability differences, the difference between CA/Cp and CE/Cp is most likely due to the concentration of lymph within the CMN. Our data suggest nodal modification of CA is correlated with the afferent lymph-to-plasma colloid osmotic pressure ratio (pi A/pi p) and further suggest that nodal alteration of lymph during elevated Pla is due to the influence of decreased pi A/pi p at the blood-to-lymph barrier. We conclude that afferent lymph is a more accurate representation of lung free interstitial fluid because collection of pulmonary afferent lymph obviates the complications introduced by the CMN. Studies utilizing efferent lymph may have overestimated lung microvascular permeability in the acute sheep preparation.

In previous studies, we observed left ventricular (LV) systolic and diastolic dysfunction in association with interstitial myocardial edema (IME) induced by either coronary venous hypertension (CVH) or lymphatic obstruction. In the present study, we examined the effects of myocardial edema induced by acute hypoproteinemia (HP) on LV systolic and diastolic function. We also combined the methods of HP and CVH (HP-CVH) to determine their combined effects on LV function and myocardial water content (MWC). We used a cell-saving device to lower plasma protein concentration in HP and HP-CVH groups. CVH was induced by inflating the balloon in the coronary sinus. Six control dogs were treated to sham HP. Conductance and micromanometer catheters were used to assess LV function. Contractility, as measured by preload recruitable stroke work, did not change in control or HP groups but declined significantly (14.5%) in the HP-CVH group. The time constant of isovolumic LV pressure decline (τ) increased significantly from baseline by 3 h in the HP (24.8%) and HP-CVH (27.1%) groups. The end-diastolic pressure-volume relationship (stiffness) also increased significantly from baseline by 3 h in the HP (78.6%) and HP-CVH (42.6%) groups. Total plasma protein concentration decreased from 5.2 ± 0.2 g/dl at baseline to 2.5 ± 0.0 g/dl by 3 h in the HP and HP-CVH groups. MWC of the HP (79.8 ± 0.25%) and HP-CVH groups (79.8 ±0.2%) were significantly greater than that of the control group (77.8 ± 0.3%) but not different from one another. In conclusion, hypoproteinemia-induced myocardial edema was associated with diastolic LV dysfunction but not systolic dysfunction. The edema caused by hypoproteinemia was more than twice that produced by our previous models, yet it was not associated with systolic dysfunction. CVH had a negative inotropic effect and no significant influence on MWC. IME may not have the inverse causal relationship with LV contractility that has been previously postulated but appears to have a direct causal association with diastolic stiffness as has been previously demonstrated.