James B. Caulfield

Aberrant Coronary Artery Origin From the Aorta Diagnosis and Clinical Significance

Twenty-one patients with anomalous coronary artery origin from the aorta are discussed, and the cases reported in the literature are reviewed. The left anterior descending (LAD) and left circumflex (Cx) arteries arose aberrantly from the right sinus of Valsalva of the aorta (RSV) in six patients. In four of these patients the connecting branch from the anomalous origin passed anterior to the aorta and the right ventricular in-fundibulum (RVinf), and in two patients, this branch passed between the aorta and RVinf. In 11 patients only the Cx was aberrant, and arose either from the RSV directly or from the right coronary artery (RCA), and passed posterior to the aorta and RVinf. In four patients the RCA arose aberrantly — in three from the left sinus of Valsalva of the aorta passing anteriorly, and in one from the left Cx passing posteriorly.Aberrant coronary artery origin from the aorta had clinical consequences only when the branch connecting the LAD and Cx to the RSV passed between the aorta and RVinf. Both our findings and those reported in the literature associate this variant with exertional sudden death in young persons. Anomalous coronary patterns can be delineated readily by selective coronary cineangiography, and as illustrated, the right anterior oblique projection can readily distinguish those prone to sudden death from the clinically insignificant variants. The former can be corrected with coronary artery bypass surgery.

1H NMR Spectroscopic Imaging of Myocardial Triglycerides in Excised Dog Hearts Subjected to 24 Hours of Coronary Occlusion

BACKGROUNDnMyocardial ischemic insult causes depression of fatty-acid beta-oxidation and increased fatty-acid esterification with triglyceride (TG) accumulation. This accumulation has been demonstrated to occur in the territory with diminished blood flow surrounding an infarct, ie, the region at risk. To evaluate whether the extent of TG accumulation in the canine heart after 24 hours of ischemia could be detected, we applied myocardial 1H nuclear magnetic resonance (NMR) spectroscopic imaging (SI).nnnMETHODS AND RESULTSnSeven adult mongrel dogs underwent 24 hours of left anterior descending coronary artery occlusion. Postmortem, the hearts were excised and the size and location of the infarct were determined. With a Philips 1.5-T clinical NMR imaging/spectroscopic system, two-dimensional (2D) 1H NMR SI was performed. TG 1H NMR chemical shift images were reconstructed from the frequency domain spectra by numerical integration. A statistically significant (P < .05) increase in TG signal intensity was demonstrated in the region at risk compared with the nonischemic control region. There was an intermediate quantity of TG in the infarct region. Biochemical determination of tissue TG content (milligrams per gram wet weight) in the control, at-risk, and infarct regions confirmed the 1H NMR measurements. Histological evaluation with oil red O staining also demonstrated graded TG accumulation in myocytes. The highest TG levels were found in the at-risk region and the lowest levels in the control region.nnnCONCLUSIONSnBy use of 2D 1H NMR SI, the present study confirms and extends previous work that demonstrates preferential accumulation of TG in the reversibly injured myocardium after 24 hours of coronary occlusion. This study provides an important step toward the clinical application of TG imaging. When TG imaging is ultimately possible, resultant data would have diagnostic, prognostic, and therapeutic implications.

Electron microscopic observations on the dystrophic hamster muscle.

A strain of Syrian hamsters with a hereditary myopathy has been developed. The disease is transmitted as an autosomal recessive, and all of the animals have histologic lesions at an early age (60-80 days). The disease usually causes death by 200-220 days, roughly one-third of the life expectancy of caged hamstersS2 The lesions as seen in the light microscope have been reviewed.lJ Many of the features seen in myopathies, particularly the more slowly developing ones, involve a complex of muscle cell degeneration and regeneration including the presence of myoblasts and infiltration of the muscle by various cells>-s This paper will deal with the degenerative aspects of the hamster lesion only. The number of muscle fibers involved in the acute degenerative process at any one time is extremely low. This, coupled with the sampling problem inherent in electron microscopy, necessitated introduction of steps to increase fiber involvement. This was accomplished by having the animals swim.

The use of microscopy as a guide to primary excision of high-tension electrical burns.

High-tension electrical burns sustained by 44 patients were of two types: one is caused by the intense heat of contact with an electric arc, and in the other flow of current against resistance of the deep tissues between arc wounds of entrance and exit produces deep thermal destruction. Microscopic studies in nine patients support the conclusions that such high-tension burns are thermal injuries, that the tissue destruction is not uniform, and that the slow evolution of unexcised wound reflects the admixture of areas of varying tissue viability which may become infected. An aggressive surgical approach designed to minimize tissue loss, avoid infection, and close wounds as early as possible was guided by intraoperative and later microscopic determinations of tissue viability. Despite a high amputation rate in our patients, it was avoided in the upper extremity in three patients, and maximal length of extremities was preserved in seven others. The use of microscopic analysis is recommended to determine the viability of tissues in thermal burns.

The altered fibrous form of vitreous collagen following solubilization with pepsin

Collagen occurs in the extracellular matrix of the bovine vitreous as fibers which have a fairly uniform diameter of approximately 195 A and exhibit an indistinct axial periodicity. Following treatment with pepsin approximately three quarters of the collagen was rendered soluble and by gel electrophoresis and comparison with calf skin collagen was shown to be composed of alpha1 chains, a high molecular weight alpha chain component, beta, as well as other high order components. No alpha2 chains were detected. The amino acid composition of the pepsin soluble collagen was different from that of other collagens composed only of alpha1 chains which suggests that it is composed of either a distinct type or mixture of alpha chains. When fibers were reconstituted from the pepsin solubilized collagen they differed markedly from the native fibers and exhibited a pronounced axial periodicity (approximately 640 A) and had diameters up to 1500 A. The difference between the reconstituted and native fibers suggests that the presence of the peptides cleaved by pepsin may be one of the factors which determines the particular fibrous form of collagen in the bovine vitreous.

Studies on Hyaluronic Acid V. Relationship Between the Protein Content and Viscosity of Rooster Comb Dermis Hyaluronic Acid

Protein accounted for an average of 8.7% w/w of the hyaluronic acid obtained from rooster comb dermis extracts and three types of peptide constituents appeared to be present. A few collagen-like fibers were closely associated with the hyaluronic acid when samples were examined in the electron microscope and collagenase treatment decreased the intrinsic viscosity from 7000-5000 ml/g to 3900-2700 ml/g. The quantities of collagen present, however, were too small to detect chemically with the methods employed. The major peptide consituent was readily separated from the hyaluronic acid by fractionation in a cesium chloride gradient or by treatment with pronase. The viscosity was decreased by the density gradient procedure but not by the pronase digestion. Repeated fractionation in a cesium chloride gradient decreased the intrinsic viscosity still further and a small peptide constituent with a high glycine and serine content remained associated with a hyaluronic acid. The data suggest that an interaction or entanglement with collagen fibers is responsible for the high viscosity of hyaluronic acid in this tissue extract and that the viscosity of purified hyaluronic acid preparations is dependent upon interactions between adjacent polysaccharide chains. Interactions between the major peptide constituent and polysaccharide chains or the small residual peptide component remaining with hyaluronic acid after extensive purification procedures, however, appear to be involved in some organized structure because the presence of the major peptide constituent minimized the decrease in viscosity that occurred when hyaluronic acid samples were lyophilized.

Microvascular ultrastructure in thermal injury: A reconsideration of the role of mediators

Much insight into the mechanism of increased vascular permeability in thermal and other injury has resulted from experiments which combine economy and elegance of design. The dye-tracer method has been used to identify areas of vascular leakage to the naked eye, and in some cases to quantify leakage. The carbon-labeling method, as used by Schoefl and others, in some instances identifies leaking vessels topographically as venules even by light microscopy, and has led to the discovery by electron microscopy of the morphologic basis of this leakage—gaps appearing between intact endothelial cells. Such gaps appear in response to histamine-like mediators. Such mediators are associated with the earliest permeability responses to mild thermal injury, but the delayed, prolonged increase in microvascular permeability is associated with carbon labeling of both capillaries and venules, raising also the possibility of direct cellular injury. Nevertheless, the inhibition of edema by anti-inflammatory drugs suggests that much of the leakage of the delayed response also may be mediated, and presumably venular. Some recent reports on the pharmacology of the “local hormones”, the kinins and prostaglandins, are considered in relation to this assumption, and in relation to their bearing on ultrastructural studies of leakage, and possibly on therapy.