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Biomedical subjects

S S Katz

Publications and source records attributed to S S Katz.

7 recordsLinked to original sources
PubMed1979

Bedside maneuvers in the diagnosis of heart disease.

Numerous other pathologic conditions are encountered. The relatively few maneuvers and drugs presented here were chosen as the ones most commonly used in daily practice. Cardiac auscultation is just one aspect of the cardiovascular examination; equal attention should be paid to determination of jugular venous pressure, jugular venous wave form, carotid upstroke characteristics, and to observation and palpation of the precordium. Finally, if the examiner keeps in mind the hemodynamic changes induced by the various maneuvers and pharmacologic agents while auscultating the heart, and if he understands the pathophysiology of the commonly encountered cardiac lesions, he should be able to diagnose heart disease and to evaluate more intelligently various murmurs and heart sounds without necessitating the use of expensive invasive or noninvasive procedures.

Adolescent↗
PubMed1978

The dissolution of cholesterol monohydrate crystals in atherosclerotic plaque lipids.

Uncomplicated human atherosclerotic plaques often contain large amounts of cholesterol esters and solid cholesterol monohydrate crystals. If such plaques are to regress the crystalline cholesterol would have to dissolve and be transported out of the arterial wall. Since cholesterol is quite insoluble in water, dissolution of plaque crystals might occur through lipids in the plaque, specifically, the cholesterol esters. As part of a study on feasibility of plaque reversal we have studied a specific step involving the dissolution of cholesterol monohydrate into cholesterol ester oil. With specific considerations of the composition and physical state of the cholesterol ester solvent, the size and form of cholesterol monohydrate crystals, the agitation rate, the temperature and the presence of water, we have found that cholesterol esters are an efficient solvent for cholesterol monohydrate crystals. The rate of dissolution was fast reaching 90% of saturation in 1 h. We conclude dissolution of cholesterol monohydrate into cholesterol ester oil is not a rate-limiting step in reversal of the atherosclerotic plaque. We suggest that transport of dissolved cholesterol from cholesterol ester oil may limit the removal. If transport of dissolved cholesterol could be enhanced, cholesterol monohydrate crystals could be rapidly dissolved and facilitate reversal of atherosclerotic lesions.

Aorta↗
PubMed1977

The storage lipids in Tangier disease. A physical chemical study.

The physical states and phase behavior of the lipids of the spleen, liver, and splenic artery from a 38-yr-old man with Tangier disease were studied. Many intracellular lipid droplets in the smectic liquid crystalline state were identified by polarizing microscopy in macrophages in both the spleen and liver, but not in the splenic artery. The droplets within individual cells melted sharply over a narrow temperature range, indicating a uniform lipid composition of the droplets of each cell. However different cells melted over a wide range, 20-53 degrees C indicating heterogeneity of lipid droplet composition between cells. Furthermore, most of the cells (81%) had droplets in the liquid crystalline state at 37 degrees C. X-ray diffraction studies of splenic tissue at 37 degrees C revealed a diffraction pattern typical of cholesterol esters in the smectic liquid crystalline state. Differential scanning calorimetry of spleen showed a broad reversible transition from 29-52 degrees C, with a maximum mean transition temperature at 42 degrees C, correlating closely with the polarizing microscopy observations. The enthalpy of the transition, 0.86+/-0.07 cal/g of cholesterol ester, was quantitatively similar to that of the liquid crystalline to liquid transition of pure cholesterol esters indicating that nearly all of the cholesterol esters in the tissue were free to undergo the smectic-isotropic phase transition. Lipid compositions of spleen and liver were determined, and when plotted on the cholesterol-phospholipid-cholesterol ester phase diagram, fell within the two phase zone. The two phases, cholesterol ester droplets and phospholipid bilayers were isolated by ultracentrifugation of tissue homogenates. Lipid compositions of the separated phases approximated those predicted by the phase diagram. Extracted lipids from the spleen, when dispersed in water and ultracentrifuged, underwent phase separation in a similar way. Thus (a) most of the storage lipids in the liver and spleen of this patient were in the liquid crystalline state at body temperature, (b) the phase behavior of the storage lipids conformed to that predicted by lipid model systems indicating lipid-lipid interactions predominate in affected cells, (c) lipid droplets within individual cells have similar compositions, whereas droplet composition varies from cell to cell, and (d) cholesterol ester does not accumulate in the splenic artery. Since Tangier patients lack high density lipoprotein, we conclude that high density lipoprotein-mediated cholesterol removal from cells is essential only for those cells which have an obligate intake of cholesterol (macrophages).

Adult↗
PubMed1976

Physical chemistry of the lipids of human atherosclerotic lesions. Demonstration of a lesion intermediate between fatty streaks and advanced plaques.

95 individual human atherosclerotic lesions from 26 persons were classified into three groups under the dissecting microscope: fatty streaks, fibrous plaques, and gruel (atheromatous) plaques. Each lesion was isolated by microdissection, its lipid composition determined by chromatography, and the physical states of the lipids identified by polarizing microscopy and in some cases by X-ray diffraction. The composition of each lesion was plotted on the in vitro phase diagram of the major lipids of plaques: cholesterol, cholesterol ester, and phospholipid. The observed physical states were compared with those predicted by the location of the lipid composition on the phase diagram. The most severe lesions (gruel plaques) had an average lipid composition of cholesterol 31.5+/-1.9%, cholesterol ester 47.2+/-2.3%, and phospholipid 15.3+/-0.5%. Their compositions fell within the three-phase zone of the phase diagram, predicting the lipids to be separated into a cholesterol crystal phase, a cholesterol ester oily phase and a phospholipid liquid crystalline phase. In addition to the phospholipid liquid crystalline phase of membranes and myelin-like figures demonstrable by electron microscopy, polarizing microscopy revealed the other two predicted phases, isotropic cholesterol ester-rich droplets and cholesterol crystals. X-ray diffraction studies verified the identity of the crystals as cholesterol monohydrate. Fibrous plaques also had an average lipid composition within the three-phase zone of the phase diagram. Polarizing microscopy revealed the presence of cholesterol monohydrate crystals and lipid droplets in all of these lesions; the droplets were predominately isotropic in 28 of the 31 fibrous plaques. Although these lesions had less free cholesterol and more cholesterol ester than gruel plaques, they were otherwise similar. Fatty streaks had compositions within both the two- and three-phase zones of the phase diagram. Compared with gruel plaques, the fatty streaks within the two-phase zone, defined as "ordinary," had more cholesterol ester, less free cholesterol, a higher cholesteryl oleate/cholesteryl linoleate ratio, a lower sphingomyelin/lecithin ratio, more anisotropic lipid droplets, and rare or no cholesterol crystals. Those lesions within the three-phase zone had many chemical and physical features intermediate between ordinary fatty streaks and gruel plaques. Moreover, 68% of these "intermediate" lesions had no cholesterol crystals by polarizing microscopy in spite of their compositions being within the three-phase zone, indicating the cholesterol ester oily phase or the phospholipid phase or both were supersaturated with cholesterol. Identification of this group of intermediate lesions provides evidence that some fatty streaks may be precursors of advanced plaques.

Adult↗