Increased sheep lung vascular permeability caused by histamine.

To see whether histamine increases lung vascular permeability to protein, we compared the effects of steady-state histamine infusions on lung vascular pressures, lung lymph flow, and lung lymph protein content with the effects of mechanically elevated lung vascular pressures on these variables in the same unanesthetized sheep. We surgically implanted catheters in the pulmonary artery, the left atrium, the superior vena cava, and a main lung lymphatic. After the sheep had recovered from surgery, we carried out steady-state experiments without anesthesia. Histamine induced a dose-related, quickly reversible increase in lung lymph flow without affecting pulmonary artery pressure, and it caused left atrial pressure to fall. During 4-hour intravenous 4-mug/kg min-1 histamine infusions, lymph flow and lymph protein clearance (lymph flow X lymph-plasma protein concentration ratio) increased more than they did with mechanically elevated pressure even though vascular pressures fell. Lymph-plasma protein ratios decreased linearly with increasing lymph flow during increased pressure experiments, but during histamine infusions the ratios did not decrease even though lymph flow increased 2-6-fold. Lymph clearance and permeability-surface area products (PS) for eight protein fractions with molecular radii ranging from 36 to 100 A decreased with increasing molecular size in base-line, increased pressure, and histamine studies. PS values for all eight fractions were significantly higher than base line in histamine experiments but not in increased pressure experiments. Four-hour intravenous histamine infusions caused moderate increases in lung water content. Left atrial infusions had less effect on lymph flow than did intravenous infusions. We conclude that histamine causes pulmonary vascular permeability to protein to increase but that the effects on exchanging vessel porosity are more modest than those suggested for systemic microvessels. Histamine should be considered a possible mediator of increased lung vascular permeability.


Dissociation constant of the norepinephrine-receptor complex in normotensive and hypertensive rats.

Previous reports have suggested that smooth muscle obtained from the thoracic aorta of spontaneously hypertensive rats is less responsive to vasoconstrictive agents than that obtained from normotensive rats. The present study was undertaken to determine whether the responsiveness of aortic muscles from normotensive and spontaneously hypertensive rats correlates with a difference in the affinity of the adrenergic receptors for norepinephrine and whether antihypertensive therapy alters the affinity of the adrenergic receptors for norepinephrine. The affinity of the adrenergic receptors for norepinephrine was determined by computing the dissociation constant of the norepinephrine-receptor complex (KDR). The values computed for KDR in aortic muscles from normotensive and spontaneously hypertensive rats that had received no antihypertensive therapy were 1.07 X 10(-7)M and 1.17 X 10(-7)M, respectively. The values computed for KDR in aortic muscles from normotensive and spontaneously hypertensive rats that had received antihypertensive therapy were 1.38 X 10(-7)M and 1.29 X 10(-7)M, respectively. The differences in these values for KDR are not significant. These results indicate that the difference in the contractility of aortic muscles from normotensive and spontaneously hypertensive rats is not related to an alteration in the affinity of the adrenergic receptors for norepinephrine and that the affinity of the adrenergic receptors for norepinephrine is not altered by antihypertensive therapy. Thus, it appears that the etiology of hypertension cannot be directly correlated with a difference in the affinity of the adrenergic receptors for norepinephrine.


Membrane currents and tension in cat ventricular muscle treated with cardiac glycosides.

The effect of cardiac glycosides on membrane currents and tension in cat ventricular muscle was studied using the single sucrose gap voltage clamp method. Complete tension-voltage and current-voltage relations were obtained in five preparations before and during treatment with dihydro-ouabain (DHO, 1.7 X 10(-5)M). After 1-2 minutes of DHO, the developed tension was 15% greater than control, but there was no change in either the slow inward (calcium) current (Ica) or the level of the outward current flowing at the end of a 300-msec depolarization (Iout). After 6-8 minutes of DHO, there was a 60% increase in developed tension, a noticeable increase in resting tension, a 20% decrease in Ica, and a smaller increase in Iout. It seems possible that the reduction of Ica was due to a reduced driving force. In preparations treated with ouabain (5 X 10(-7)M, 3-5 minutes), developed tension was 45-150% greater than control with no change in Ica or Iout between -45 and + 15 mv. We conclude that the inotropic action of these cardiac glycosides is not mediated by an increase in Ica.


Role of prostaglandins in the reversal of one-kidney hypertension in the rabbit.

Hypertensive rabbits with a clip on the renal artery of their solitary remaining kidney show an abrupt decrease in blood pressure after the arterial constriction is released. Although the mechanism underlying this phenomenon remains controversial, some experimental evidence suggests that it could be humorally mediated. The involvement of prostaglandins was investigated by examining the effect of the release of the arterial constriction on blood pressure, renal blood flow, glomerular filtration rate, and urinary output in five conscious single-kidney hypertensive rabbits in which prostaglandin synthesis was blocked with indomethacin (priming intravenous injection of 9 mg/kg followed by a constant infusion of 1 mg/kg hour-1). The results were compared with those obtained in another group of five single-kidney hypertensive rabbits submitted to the same protocol but not treated with indomethacin. The blockade of prostaglandin synthesis with indomethacin prevented the increments in renal blood flow and glomerular filtration rate seen in the control rabbits after unclipping a significantly retarded the appearance of diuresis and the fall in blood pressure. Despite these observations, the results do not indicate a major participation of prostaglandins in the reversal of single-kidney hypertension, because the decrease in blood pressure 9 hours after the removal of the arterial constriction was similar in both groups.


Chronic one-kidney hypertension in rabbits. I. Treatment with kidney extracts.

An investigation into the mechanism that sustains the blood pressure in chronic one-kidney hypertension in rabbits was made using passive and active immunization with hog kidney extracts containing renin and with angiotensin antagonists. Seven hypertensive rabbits were passively immunized for extended periods with antiserum prepared in other rabbits. Antirenin levels were in the range of 1-3 units/ml. Control experiments demonstrated that antirenin concentrations of 1.0 unit/ml or more eliminated more than 99% of the pressor response to renin. There was no lowering of blood pressure that could be attributed to the antibodies. No decrease in blood pressure was observed in 13 experiments in 7 rabbits given the angiotensin II antagonist 1-Sar-8-Ile-angiotensin II; infusion rates of 0.09-87 mug/min kg-1 were used for periods of a few hours up to 3 days. A reduction in blood pressure occurred in 16 of 19 rabbits immunized directly with extracts containing renin with specific activities of 9.6-757 GU/mg. Plasma antirenin titers correlated poorly with reductions in blood pressure. The blood pressure of 22 rabbits given equal amounts of protein without renin was unaffected. It is concluded that the elevation of blood pressure in rabbits with chronic one-kidney hypertension is not dependent on ciculating renin or angiotensin; rather, it results from the presence of renin in an extravascular location or from an unknown pressor substance.


Expansion of extracellular space in the nonischemic zone of the infarcted heart and concomitant changes in tissue electrolyte contents in the rat.

The alterations in electrolyte content that occur in an infarcted zone of the heart have also been reported to occur in a similar manner, although to a far less degree, in the distant, apparently normal zones of the heart. These alterations in the nonischemic myocardium have usually been tabulated without comment, presumably because their magnitudes approach values of statistical dispersion. Our measurements of electrolyte content in the normal zone of the infarcted rat heart confirmed that all of the electrolyte contents were slightly modified. There was a rise in sodium, calcium, and chloride and a decline in potassium and magnesium. In addition, the extracellular space ([14C]sucrose) in this zone was elevated by nearly 15%. We have postulated a mechanism for this elevation based on an increase in the net filtration rate through myocardial capillaries. The expansion of the extracellular space can account for all of the electrolyte changes in the normal zone with the exception of the alteration in calcium. Therefore, there is no basis for assuming that these myocardial alterations reflect general movements of electrolytes down their electrochemical gradients. We suggest that the increment in the nominal concentration of cellular calcium is related to a compensatory mechanism that allows the reduced mass of functional myocardium to contract more vigorously.


Analysis of coronary flow fields in thoracotomized dogs.

A nonlinear theory of pulsatile flow was used to investigate the detailed flow field in the left circumflex coronary artery of anesthetized open-chest dogs. Studies were carried out under a wide range of blood pressures and flow rates induced by intravenous infusions of dipyridamole. The results indicated that (1) the flow profiles, although less blunt than those in the descending aorta, are still nonparabolic, (2) the wall shear in the coronary arteries maintains a high value through diastole, and (3) during intravenous infusions of dipyridamole both coronary flow and wall shear increase. The peak value of the shear stress during these infusions, which reached 360 dynes/cm2, can approach the yield stress value of 400 dynes/cm2 reported by Fry for endothelial cells.


Baroreceptor reflex control of arterial hemodynamics in the dog.

The regional differentiation of carotid sinus control of arterial pressure-flow relationships was studied in chloralose-anesthetized dogs. Simulatneous pressure-flow measurements were made in the ascending aorta, the celiac artery, the cranial mesenteric artery, the renal artery, and the femoral artery. The carotid sinuses were bilaterally isolated and perfused with pulsatile pressure. The open-loop reflex gain was not symmetrical about and was maximum at pressures below the closed loop operating point pressure. Changes in both peripheral resistance and cardiac output contributed significantly to the open-loop gain with the former predominating. Aortic impedance for frequencies above 3 Hz was at a minimum at the closed-loop operating point and increased for both higher and lower values of carotid sinus pressure. For the frequency range from 3 to 9 Hz, regional impedance in all of the beds varied inversely with carotid sinus pressure. The sensitivity of the various beds to changes in carotid sinus pressure around the operating point increased in the order celiac less than mesenteric less than renal less than femoral. Following vagotomy, operating point values of regional resistance and sensitivity were significantly increased. This fact suggests that the aortic arch receptors exert a significant influence on regional vascular impedance at operating point pressures. The fraction of cardiac output in the celiac, mesenteric, and renal beds was nearly independent of carotid sinus pressure before and after vagotomy, but that in the femoral bed increased with carotid sinus pressure. These results demonstrate the nonuniform nature of carotid sinus and aortic arch baroreceptor control of regional blood flow.


Muscle stiffness determined from canine left ventricular pressure-volume curves.

We measured pressure-volume curves in nine excised dog ventricles and stress-strain curves in two to five muscle specimens from each ventricle to verify a derived formula that relates muscle stiffness to the ventricular pressure-volume curve. The assumptions underlying this formula are: (1) the ventricle is a uniform spherical shell, (2) all muscle fibers carry average stress and deform as if they were at the midwall, (3) static equilibrium exists, (4) internal pressure induces the only load, and (5) the muscles exhibit an exponential stress-strain curve given by the equation sigma(epsilon) = alpha(ebeta epsilon - 1), where sigma = stress, epsilon = strain, and alpha and beta are constants. There was no significant difference between the stiffness constant, beta, inferred from the left ventricle pressure-volume curves (14+/-4.3[SD]) and that measured directly from the muscle stress-strain curves (16+/-2.8).


Hypotensive effect of clonidine during sodium depletion in the rat.

Clonidine was nonhypotensive in conscious unrestrained rats maintained on a normal sodium intake. In contradistinction, clonidine caused a dose-related hypotension in conscious unrestrained rats subjected to sodium depletion via furosemide. The plasma renin activity of normal and sodium-depleted rats was reduced after the administration of clonidine (100 mug/kg, iv) by 22.8% and 34.4%, respectively. Intravenous infusion of an angiotensin II antagonist, 1-Sar-8-Ala-angiotensin II, caused a significant reduction of arterial blood pressure in sodium-depleted rats but not in normal rats. Similarly, bilateral nephrectomy reduced arterial blood pressure and completely abolished the hypotensive effect of clonidine in sodium-depleted rats. Subcutaneous administration of chlorisondamine caused a significantly greater reduction of arterial blood pressure in sodium-depleted rats than it did in normal rats. Treatment of normal and sodium-depleted rats with 6-hydroxydopamine reduced the arterial blood pressure of both groups to approximately 85 mm Hg and completely abolished the hypotensive effect of clonidine in the sodium-depleted rats. The data presented in this paper are consistent with the conclusion that clonidine acts at some site in the sympathetic nervous system of sodium-depleted rats to inhibit renal nerve activity with a resultant suppression of renin secretion and a reduction of the angiotensin II-maintained arterial blood pressure. A similar sequence of events occurring in normal rats would not result in hypotension because their arterial blood pressure is not maintained by angiotensin II.


Hormone interactions in the isolated rabbit heart. Synthesis and coronary vasomotor effects of prostaglandins, angiotensin, and bradykinin.

In the present study, the synthesis and degradation of several potent vasoactive substances influencing coronary resistance were characterized in the isolated perfused rabbit heart. Prostaglandin synthetase activity, angiotensin converting enzyme activity, and bradykininase activity (without angiotensinase) were observed. A prostaglandin E2-like substance appeared to be the ednogenous mediator of the coronary vasodilation produced by bradykinin and angiotensin II (AII). (1) The concentration of this prostaglandinlike substance in the coronary venous effluent was directly proportional to the concentration of the coronary vasocilator stimulus (bradykinin or AII). (2) The prostaglandinlike substance released and the coronary dilation produced by the agonists correlated temporally and quantitatively. (3). Abolition of cardiac biosynthesis of the prostaglandinlike substance by indomethacin also abolished the decrease in coronary resistance produced by the agonists. AII, the most potent naturally occurring vasoconstrictor substance, produced a paradoxical coronary vasodilation because it stimulated cardiac prostaglandin biosynthesis, but the direct coronary vasoconstrictor action of AII could be readily unmasked by indomethacin, which blocks prostaglandin synthesis. The nonapeptide SQ-20881 blocked cardiac biosynthesis of AII (from angiotensin I) and enhanced the coronary vascular effects of bradykinin by interfering with bradykininase activity. Similarly, the AII-receptor antagonist, 1-Sar-8-Ile-AII, blocked the coronary vascular effect of AII.


Pressure-flow and pressure-volume relations in the entire pulmonary vascular bed of the dog determined by two-port analysis.

To quantify the resistance and particularly the capacitance properties of the entire pulmonary vascular bed, isolated perfused lungs of nine dogs were studied. In each dog, with a fixed endotracheal pressure of 5 mm Hg, the arterial pressure-flow and pressure-volume relations were determined while venous pressure was fixed at constant values of 2, 5, and 8 mm Hg. In the same dogs, the venous pressure-flow and pressure-volume relations were also obtained when arterial pressure was fixed at constant values of 15 and 20 mm Hg. The arterial and venous pressure-flow relations could be regarded as linear around the physiological ranges of arterial and venous pressures; however, at very low pressures, these relations became nonlinear. The arterial and venous pressure-volume relations were also approximately linear within the physiological pressure ranges. The mean arterial compliance was 0.1798 ml/mm Hg kg-1 and was independent of venous pressures. The venous compliance values were 0.1236 and 0.0955 ml/mm Hg kg-1 for arterial pressures of 15 and 20 mm Hg, respectively. The sums of the arterial and venous compliances were 0.3034 and 0.2753 ml/mm Hg kg-1 for arterial pressures of 15 and 20 mm Hg, respectively. These values were nearly identical to the mean total compliance, 0.3265 ml/mm Hg kg-1, measured in a separate series of experiments in the same dogs. Therefore, the data obtained in these experiments using two-port analysis techniques represent the compliances and the resistance of the entire pulmonary vascular bed around the normal operating pressures and flows.


Glomerular filtration response to elevated ureteral pressure in both the hydropenic and the plasma-expanded rat.

The factors affecting glomerular ultrafiltration with elevated ureteral pressure were examined in both plasma-expanded (2.5% body weight) and hydropenic Munich-Wistar rats. Elevated ureteral pressure (20 mm Hg) alternated as the initial condition in both groups. Glomerular capillary hydrostatic pressure (PG) and Bowman's space pressure (Pt) were measured directly in surface glomeruli with a servonulling device (deltaP = PG - PT), systemic (piA) and efferent (piE) peritubular capillary oncotic pressures were estimated by microprotein methods, and single-nephron glomerular filtration rates (sngfr) were determined by micropuncture techniques under control ureteral pressure and after increased ureteral pressure in both experimental groups. All data were then applied to equations describing the process of glomerular ultrafiltration to define the profile of effective filtration pressure (EFP = deltaP - pi) and the glomerular permeability coefficient (LpA), where sngfr = LpA-EFP. In plasma-expanded rats, sngfr fell from 44.8 +/- 2.2 to 38.5 +/- 1.5 nilters/min g-1 kidney weight (P less than 0.025) with elevated ureteral pressure entirely as a result of a decrease in the hydrostatic pressure gradient (deltaP), since PG did not rise and nephron plasma flow remained constant. In hydropenic rats, sngfr fell from 34.7 +/- 1.6 to 27.3 +/- 1.6 nliters/min g-1 kidney weight with increased ureteral pressure. PG rose 8.7 mm Hg (P less than 0.001) due to an increase in vascular resistance between the peritubular capillaries and the renal vein which prevented the reduction in deltaP. The reduction in sngfr appeared to result from a reduction in LpA resulting in disequilibration of EFP. Nephron plasma flow was not changed. The filtration response to elevated ureteral pressure was modified by the prior state of volume expansion and was not associated with changes in either nephron blood flow or afferent arteriolar resistance.


Anaylsis of ventricular activation and repolarization from intramural and epicardial potential distributions for ectopic beats in the intact dog.

Ventricular activation and repolarization were examined by measuring intramural and epicardial potential distributions during ectopic sequences in intact dogs. Potential distributions were used because they provided a direct measure of all of repolarization. Ectopic sequences produced almost unidirectional excitation across the heart along with repolarization events that were different from normal. During ectopic repolarization, positive potentials occurred over a broad area surrounding the ectopic focus, and negative potentials occurred over a large area on the opposite side of the heart where excitation terminated. The potentials in the walls of both ventricles were more positive in the outer layers and more negative in the inner layers, a gradient similar to normal. A maximum initially was at the ectopic site with a magnitude greater than that of the minimum, but the maximum subsequently decreased in magnitude and shifted toward the minimum while the minimum increased in magnitude. The steepest gradients were initially around the maximum, and they then shifted toward the minimum. The results show that ventricular repolatization potential distributions during ectopic beats are predominantly influenced by gradients from one side of the heart to the other (transventricular gradients) in  contrast to normal repolatization distributions which are predominantly influenced by gradients across the wall (transmural gradients).


Electrophysiological actions of disopyramide phosphate on canine ventricular muscle and purkinje fibers.

Disopyramide phosphate is a new antiarrhythmic drug that has been shown to possess significant antiarrhythmic effects in animals and man. In the present investigation, the effects of 2, 5, and 10 mug/ml of disopyramide phosphate were studied on the electrophysiological properties of canine Purkinje fibers and ventricular muscle superfused in vitro. Transmembrane action potentials were recorded from Purkinje fibers in the region of maximum action potential duration (gate), from Purkinje fibers proximal and distal to the gate, and from ventricular muscle. Disopyramide phosphate produced a concentration-dependent decrease in the slope of phase 4 diastolic depolarization of spontaneously beating Purkinje fibers. In all electrically stimulated fibers, the drug decreased the amplitude and the maximum upstroke velocity of the action potential. This depression of phase 0 characteristics was accompanied by a decrease in conduction velocity. In Purkinje fibers located at the gate, a concentration-dependent parallel shift to the right and a depression of the maximum of the membrane responsiveness curve occurred. Effects on action potential duration were variable. Repolarization was altered so that action potentials with dissimilar durations recorded from sites proximal to, at, and distal to the gate became equal. The total action potential duration and the effective refractory period of gate Purkinje fibers were prolonged, but the change in action potential duration was always greater than the change in effective refractory period so that the ratio of the change in duration to the change in refractory period was always greater than one.


Norepinephrine turnover in the heart and spleen of the cardiomyopathic Syrian hamster.

Although a reduction in myocardial norepinephrine stores in cardiac hypertrophy and congestive failure is well documented, norepinephrine turnover has been inadequately studied in such hearts. We compared norepinephrine turnover in control and cardiomyopathic hamsters by following the decline in specific activity of myocardial norepinephrine after labelling with an intraperitoneal tracer dose of 3H-norepinephrine. Adult myocardial norepinephrine concentrations were not attained until 4 weeks of age in both strains. There was no difference in the rate of constant (K) for myocardial norepinephrine turnover (0.107+/-0.004 hours-1 vs. 0.100+/-0.005 hours-1) in the two strains of hamsters during the neonatal period. In young control hamsters, K fell to 0.064+/-0.004 hours-1, but that for age-matched hamsters with mild cardiac hypertrophy was 0.102+/-0.001 hours-1 (P less than 0.001). There was little change in K as control hamsters aged. With the development of more severe hypertrophy in cardiomyopathic hamsters, cardiac norepinephrine decreased and resting K rapidly increased to approach the value obtained when hamsters were subjected to immobilization stress (0.302+/-0.013 hours-1). The maximum achievable K remained the same for both control and dystrophic hamsters even during terminal disease. Prolonged immobilization led to a reduction in cardiac norepinephrine in both strains. Ganglionic blockade of failing hamsters completely restored the levels of both cardiac norepinephrine and K to control values. Splenic noradrenergic nerves showed no change in K, norepinephrine content, or maximum K during cardiac decompensation. We conclude that, in the late stages of hamster cardiomyopathy, there is a progressive and possibly specific increase in cardiac sympathetic tone which leads to a concomitant decrease in cardiac norepinephrine. With the loss of sympathetic reserve, congestive failure supervenes.


Current concepts of "normal values," "reference values," and "discrimination values," in clinical chemistry.

The term "normal values" is seriously afflicted by sylleptic ambiguities and conceptual problems, and it is gradually being discarded from the lexicon of clinical chemistry. The neutral term "reference values" preferable on semantic and scientific grounds, and its use in clinical chemistry is rapidly gaining acceptance. The term "discrimination value" has been added to the lexicon of clinical chemistry. Use of the "discrimination value" for the results of a laboratory test in a specified clinical situation provides the optimal discrimination between the "healthy" and the "diseased," or between "those who need not be investigated further" and "those who do."


Radioimmunoassay of methaqualone and its monohydroxy metabolites in urine.

A commercial radioimmunoassay kit was evaluated for efficacy in detecting methaqualone or its metabolites in urine of persons receiving this drug. The drug and its unconjugated 3'- and 4'-monohydroxy metabolites could be detected equally well. The unconjugated alpha-monohydroxy metabolite was about 80% as reactive and the unconjugated 6-monohydroxy metabolite reacted only very weakly. Quantitation of the conjugated metabolites was less sensitive than of unconjugated. Nineteen urine specimens which reacted positively to radioimmunoassay and which thin-layer chromatography had shown to contain methaqualone and its metabolites were also examined by gas-liquid chromatography. Those specimens that reacted strongly to radioimmunoassay contained high concentrations of the drug or its metabolites. In the specimens examined by gas-liquid chromatography, the apparent concentrations of the metabolites were generally higher than those of the drug itself. Methaqualone in combination with its unconjugated metabolites reacted additively with the radioimmunoassay, resembling the same concentration of parent drug alone. Detection limits were between 10-200 mug/liter.


Separation of synthetic mixtures of sugars and of sugars in body fluids with a high-resolution carbohydrate analyzer.

With use of a specially designed gradient-generating system, of anion-exchange resins of 10-20 mum particle diameter, and of an orcinol solution in concentrated sulfuric acid (1 g/liter) as detection reagent, a mixture of 16 carbohydrates can be separated in less than 4 h. The limit of detection for most sugars is in the 0.1--2.0 nanomole range. The detection reagent is stable for months and does not become colored. The reagent mixes with the column effluent in an exothermic reaction and allows use of relatively short mixing coils. The analyzer is appropriate for investigating body fluids rapidly and with high sensitivity.


Gas-chromatographic/mass-spectrometric identification and quantitation of tetronic and deoxytetronic acids in urine from normal adults and neonates.

Gas chromatographic/mass spectrometric/computer analyses of trimethylsilyl derivatives of urine extracts, prepared by an anion-exchange procedure, reveal the presence of several tetronic and deoxytetronic acids. Identifications were confirmed by comparing gas-chromatographic methylene unit values and mass spectrometric characteristics with those of chemically synthesized samples. In addition, several 1,4-lactones corresponding to the acids were detected in small amounts. The acids were measured in groups of adults and neonates by gas chromatographic/computer determination of peak areas and the use of calculated response factors. In urines from adults, 4-deoxythreonic, threonic, and erythronic acids were present in relatively large amounts. 4-Deoxyerythronic and 2-deoxytetronic acids were present in small to moderate amounts; 3-deoxytetronic and 2-methylglyceric acids were only trace constituents. These latter two acids, in addition to 4-deoxyerythronic, were also trace constituents of several urines from neonates but could not be detected in others. Expressed in terms of creatinine excretion, both groups excreted similar amounts of 4-deoxythreonic acid and neonates excreted significantly more 2-deoxytetronic, erythronic, and threonic acids.


Factors influencing evaporation from sample cups and assessment of their effect on analytical error.

We studied sample evaporation and its effect on analytical error. Several factors influencing evaporative loss have been identified and measured: environmental, instrumental, and operational factors, and the chemical and physical properties of the sample and its container. Such losses from several different types of sample cups have been measured, either chemically or gravimetrically, and compared with those calculated by using a model that allows evaporative loss from a cup of known geometry to be predicted under various environmental conditions. We discuss some steps that may be taken to minimize evaporative loss and give an example to demonstrate that analytical error from this source can be decreased to a routine 1--2% or less by selecting a  particular cup design.


Gas-chromatographic analysis for cocaine in human plasma, with use of a nitrogen detector.

We describe a procedure for measuring the concentration of cocaine in plasma by gas chromatography, with use of a nitrogen detector. The procedure was tested on patients receiving intranasal cocaine for topical anesthesia. The propyl ester of benzoylecgonine is used as an internal standard. The lower limit of sensitivity of the procedure is 5--10 mug of cocaine per liter of plasma. The coefficients of variation are 5.3% and 3.0% for concentrations of 50 and 100 mug/liter, respectively.


Comparison of commercial kits for radioimmunoassay: III. Radioassay of serum folate.

We evaluated six commercial radioassay kits in which tritium or iodine tracers are used to measure serum folate. We assessed the adequacy of the literature supplied with the kits, within-run precision, reagent stability, analytical recovery of added pteroylglutamic acid and N-methyltetrahydrofolic acid, results of analysis of patients' samples, and minimum detection limits. There were serious discrepancies among manufacturers' kits in each of these respects. Such discrepancies could affect interpretation of results and of data on like samples derived from different laboratories that are using different kits. Laboratories are urged to assess carefully the materials and method supplied by a manufacturer before putting a kit to clinical use.


Relative efficacy of separation of "free" and "bound" (3',5'-3H) pteroylglutamate by charcoal coated with various materials.

We studied the effectiveness with which various charcoal preparations separate free [3H]pteroylglutamate from that complexed with milk folate binder. We tested, in various concentrations, uncoated charcoals and charcoals coated with dextrans of various molecular weights, or with albumin, hemoglubin, or polyvinylpyrrolidone with an average molecular weight of 40 000. Althouth there was some distinction between the "bound" and "free" fractions with all charcoals, those treated with dextrans of average molecular weights of 43 500 or 70 000, or with polyvinylpyrrolidone gave the best separation over a greater range of charcoal concentration. Uncoated charcoal and charcoals coated with albumin, hemoglobin, or dextran T10 (average molecular weight, 10 500) were least effective.


Accurate estimation of standard deviations for quantitative methods used in clinical chemistry.

Although the standard deviation is the most widely used measure of the precision of quantitative methods, there is a need to re-examine the conditions necessary to obtain a meaningful estimate of this quantity. The importance of the material to be sampled, the sample size, the calculation of confidence intervals, and the segregation of outliers are discussed.


A systematic approach to enzyme assay optimization illustrated by aminotransferase assays.

We have developed a systematic approach to optimization of reagent concentrations for assays of alanine aminotransferase and aspartate aminotransferase: (a) Michaelis constants describing the initial-velocity kinetics of the coupled enzyme reactions were evaluated by a nonlinear least-squares fit of the appropriate equation to measured enzyme activities. Activities of more than 50 normal and pathological sera were measured at 30 degrees C. (b) These kinetic equations are used to calculate the set of reagent amino- and keto-acid concentrations that all yield a selected fraction of the theoretical maximum enzyme velocity. An optimal pair is determined by defining an additional criterion, such as minimal reagent cost or minimal concentration to Km ratio. (c) The optimum amounts of reagent NADH and coupling enzyme, being a function of desired pre-incubation and measurement intervals, maximum aminotransferase activity to be measured, and endogenous keto-acid concentration, are determined by computer simulation. An approximate relationship and an exact method for computing assay lag time are presented, along with experimentally measured endogenous keto-acid concentrations in serum. All procedures may be applied to other enzyme assays if appropriately modified.


Identification of human hemoglobins by use of isoelectric focusing in gel.

Newly-developed gel isoelectric focusing techniques provide for rapid and correct identification of human hemoblobins. With this technique, we examined samples previously identified by the National Hemoglobinopathy Standardization Laboratory of the Center for Disease Control. A wide variety of both normal and abnormal hemoglobins was included in the 134 different specimens examined. The isoelectric points (pl's) were precisely determined; no discrepancies with results by standard techniques of identification were found. The method is accurate and precise. It is proposed as a powerful adjunct to other laboratory methods suitable for use in a hemoglobinopathy reference laboratory or specialized hematology service laboratory.


Gas-chromatographic measurement of codeine and norcodeine in human plasma.

A gas-chromatographic method is described for determination of codeine and norcodeine in human plasma. The method is specific, sensitive, and precise. It was developed for use in bioavailability studies of therapeutic doses of codeine sulfate. After ingestion of a 60-mg codeine sulfate tablet, mean peak codeine concentration in plasma was 107 mug/liter at 1.0 hour. No measurable concentration of norcodeine was found in the plasma by this method.


Temporal intrapersonal physiological variability of cholinesterase activity in human plasma and erythrocytes.

Erythrocyte and plasma cholinesterase activities were measured biweekly in one group of 22 subjects for a year and daily for three weeks in another group of nine men. The average range [i.e., (range/mean) X 100] of activity of erythrocyte cholinesterase in men during a year was 8% and during three weeks was 5%. For plasma, the corresponding values were 25% and 12%. The average ranges for erythrocyte and plasma cholinesterase activity in women during a year were 12% and 24%. Erythrocyte cholinesterase activity varies less than do hematocrit, hemoglobin, or erythrocyte count.


5-Decynedioic acid, an acetylenic compound in human urine.

An acetylenic dicarboxylic acid, 5-decynedioic acid, has been isolated from human urine. The structure was determined by mass spectrometry of several derivatives, and by infrared spectroscopy. On osmium tetroxide oxidation, a vic-diketone was formed, the mass spectrum of which established the position of the triple bond between carbon atoms 5 and 6. Mass spectrometric evidence for the presence of a small amount of the isomeric 4-decynedioic acid was also obtained. The 24-h excretion of these acids is 0.01-0.1 mmol for healthy adults on a regular diet.


Sex-related patterns in the profiles of human urinary amino acids.

The urinary amino acid profiles of 79 young women and 72 young men were studied with an automated highpressure amino acid analyzer. A nonparametric statistical analysis was applied for detecting profile differences related to sex and other variables. A strong sex-related pattern was confirmed and its power for sex determination was evaluated. For the women, profile differences related to the use of oral contraceptives were also discovered and evaluated. No correlation with the menstrual cycle was detected.


Fluorometric screening method for detecting benzodiazepines in blood and urine.

We report a fluorometric method for detecting diazepam, chlordiazepoxide, oxazepam, chlorazepate, and (or) their major metabolites in blood, urine, or gastric contents at low therapeutic concentrations. The drugs are first hydrolyzed to their respective benzophenones and converted to highly fluorescent 9-acridanones. Total benzodiazepines (parent plus metabolites) in blood and gastric contents are semiquantitatively evaluated and compared to results of gas-chromatographic determinations.


Faster enzymatic procedure for serum triglycerides.

We describe a single-reagent, enzymatic procedure for triglycerides in serum, which may be performed in 5 min per sample with use of an Abbott ABA-100 analyzer system. This procedure is compared to the semi-automated enzymatic procedure with the ABA-100, which requires 30 min per sample.


Use of the carbon rod atomizer for analysis of lead in blood: three methods compared.

Measurement of lead in whole blood by use of the carbon rod atomizer and atomic absorption spectrophotometry was investigated for three methods: (a) a simple dilution (one volume of whole blood to two volumes of surfactant solution; (b) direct analysis of whole blood (no sample preparation); and (c) a standard chelation extraction procedure in which sodium diethyldithiocarbamate and methyl isobutyl ketone (isopropylacetone) are used. Within-run precision data for normal and above-normal pools favored the Triton dilution method, for which coefficients of variation were less than 5%. Recoveries of added lead ranged from 94-107% for all three methods. We saw no change in the standard curves for any of the procedures on addition of ethylenediaminetetraacetate to samples. The method of additions was necessary to prepare standards of a matrix composition identical to that of the unknowns.


Rapid, simplified diagnosis of cystinosis in conjunctival biopsies.

Assessment of the markedly elevated concentration of free cystine in conjunctival tissue from patients with cystinosis permits a rapid, simple, and unequivocal diagnosis of this disorder of amino acid metabolism.


Distinction between fibrinogen and fibrin degradation products in plasma.

Polyacrylamide (PA) gel electrophoresis in sodium dodecyl sulphate (SDS) has been shown to distinguish between the major components in the plasmin induced lysates of purified crosslinked fibrin and fibrinogen. The D dimer fragment from crosslinked fibrin separated on SDS-PA gels from the fibrinogen fragments X, Y, Dg and E. Follwing immuno-absorption of plasmin induced lysates of plasma clots, plasma fibrinogen, and mixtures of both, the major fragments of fibrinogen and fibrin were capable of being discriminated by SDS-PA gel electrophoresis. The presence of D dimer in patient plasma suggested the efficacy of heparin in the management of haemorrhage associated with amniotic fluid embolism.


The effect of heparin in vitro on human plasm post-heparin lipolytic activity.

Human plasma post-heparin lipolytic activity was reduced when collected in tubes containing lithium heparin as compared with samples collected in lithium sequestrene. The addition of heparin in vitro to samples abolished the inhibitory effect of protamine sulphate on plasma post-heparin lipolytic activity. It is suggested that heparin should not be used as an anticoagulant for the collection of samples for assay of post-heparin lipolytic activity.


A new fat-dependent time-modified relationship between basal plasma glucose levels and the early glucose response to oral glucose loading in normal human subjects.

Plasma glucose responses to 50 g oral glucose loads were measured in 17 young healthy males during the morning and the afternoon after 4-h and 12-h fasts. After 4-h fasts certain glucose response values correlated significantly with the basal glucose values (P less than 0.014) in both the morning and the afternoon tests, and are described as "fast-dependent" relationships. No significant correlations were found after 12 -h fasts either in the morning or the afternoon. The "fast-dependent" relationships are also "time-modified", as demonstrated by markedly different morning and afternoon regression equations.


Evaluation of a radioassay for serum folate and the effects of ascorbate and methotrexate.

In this study a competitive binding assay for serum folate is evaluated with special attention to storage conditions of the serum samples and the effect of methotrexate on the assay results. Average serum folate levels were 31 nmol/1 +/- 8 (S.D.) in 59 nromal sera and 19 nmol/1 +/- 12 (S.D.) in 354 sera from hospitalized patients of which 43 values were lower than 9 nmol/1. Serum folate appeared to be stable at - 20 degrees C for at least 5 weeks. The addition of ascorbate, which is said to stabilize serum folate, caused a non-specific increase of the measured folate. Methotrexate acted competitively with the tracer folate in the assay sytem when added  in vitro and elevated the folate readings. The same occurred in the serum of a patient after intravenous methotrexate.


Glyoxalase enzyme system in human muscular dystrophy.

Glyoxalase I and glyoxalase II activities were determined in skeletal muscle of control subjects and of patients with Duchenne dystrophy, other major forms of muscular dystrophies and certain neuromuscular disorders. The glyoxalase I activity was normal in all diseases examined except in Duchenne and limb girdle types of muscular dystrophy, where it showed a significant moderate decrease. The glyoxalase II activity in normal human muscle was very low, and the activity was unaltered in muscle of patients with Duchenne and other major forms of muscular dystrophies and spinal muscular atrophy. The selective decrease of glyoxalase I activity in recessively inherited muscular dystrophies may have some relevance to some phases of these disease processes.


An automated, direct method for measuring adipocyte cell size.

Current methods for direct determination of fat cell size are optical and non-automated. They are thus tedious, but have the advantage of providing estimates of the variance of a cell size distribution, as well as a measure of the mean cell size. An indirect method based on counting the number of osmium-fixed fat cells derived from a known wet weight of adipose tissue is also available. This method is automated and thus rapid, but does not provide information about the variance of the cell size distribution. In the present paper we describe a direct, automated method of fat cell sizing that provides estimates for both mean cell size and the variance of the cell size distribution. The correlation between our method and in indirect method based on counting osmium-fixed cells was 0.96. Transformation of the volume distribution to diameters indicated that cell diameters appeared to be normally distributed, confirming the observations of others.


Serum alkaline phosphatase isoenzymes linked to immunoglobulin G.

An unusual isoenzyme pattern of serum alkaline phosphatase was found in a patient with skeletal abnormalities due to multiple epiphyseal dysplasia and it was demonstrated that the abnormal pattern was caused by complex formation between serum alkaline phosphatase and immunoglobulin G of the lambda class. Physicochemical studies of the patient's serum alkaline phosphatase showed the properties of an osseous enzyme. Evidence was obtained indicating that the complexing occurred in vitro and that the patient's immunoglobulin G had the ability to bind the hepatic and osseous isoenzymes selectively but not to bile, placental and intestinal isoenzymes. No abnormality was detected in the leucocyte isoenzyme pattern. The relationship between the occurrence of complex formation and the patient's bone disease was not established.


Lecithin:cholesterol acyltransferase initial fractional rates of esterification in human and rat serum during development.

The initial fractional rates of cholesterol esterification were measured in human cord serum, in a group of apparently healthy "young adults" (mean age +/- S.D. 32 +/- 5 years), in a group of "middle aged" adults (51 +/- 8 years) with normal coronary angiograms and in newborn, 10-, 20-, 45-, 180- and 365-day-old rats. The initial fractional rate of esterification was inversely related to serum cholesterol levels in humans and, with the exception of newborns, also in rats. A theory of lecithin:cholesterol acyltransferase participation in cholesterol metabolism is discussed.


The effect of long-distance running on some biochemical variables.

Biochemical variables have been measured in a group of volunteers during and after a long-distance run. Plasma glucose levels remained relatively constant and a significant decrease in plasma bicarbonate was noted. Plasma sodium, chloride, total protein, albumin and calcium showed significant increased of an order compatible with water losses occurring during the run. Plasma potassium, urea, creatinine, uric acid, phosphate and bilirubin all show much more marked and variable increases. The plasma enzymes alkaline phosphatase, lactate dehydrogenase, aspartate aminotransferase and creatine kinase likewise increased significantly throughout the run. Whilst most constituents showed a tendency to return to normal at 20-30 hours after the run, gross increases were observed for aspartate aminotransferase and creatine kinase.


Fluid balance, renal function, and blood pressure.

After many detours in the search for the basic mechanism of hypertension, evidence now seems to corroborate the earliest concept that developed in the 1800's, namely, that hypertension almost always results from a tendency of the kidneys to retain water and salt. Animal studies show that the amount of excess body water and salt required to cause hypertension is exceedingly small, and that the hypertensive effect of the excess water and salt may not develop for days or weeks. When vascular constriciton occurs simultaneously, as occurs in the presence of large quantities of angiotensin, the blood volume may be less than normal, but even in these circumstances the fluid volume is relatively increased and is responsible for the hypertension because the vascular constrictont has decreased the capacity of the circulation to a greater extent than the decrease in blood volume.


Renal control of interstitial space compliance: a physiological mechanism which may play a part in the etiology of hypertension.

"Overloading" with salt and water, i.e., increasing extracellular fluid, can, if maintained for a period, lead to hypertension in which the main hemodynamic abnormality is increased peripheral resistance. There is evidence that salt and water overload is the chief factor in the hypertension of the majority of patients suffering from chronic renal failure. "Overloading" occurs not only when the contents of a container are increased, but also when the capacity of a container is decreased. Reduction of the compliance of the interstitial space would reduce its capacity to hold fluid without increase in pressure. Evidence is presented that the presence of the kidney affects interstitial space compliance; bilateral nephrectomy decreases interstitial space compliance four fold. Hypertension induced by renal artery partial constriction and removal of the other kidney is also associated with reduction of interstitial space compliance; a sudden rise in interstitial space compliance may be the primary factor in the course of events that leads to the rapid fall in blood pressure which occurs when the constriction is removed from the renal artery. It is suggested that the kidney secretes a hormone which increases interstitial space compliance and that this represents a physiological mechanism which enables animals to store water in the interstitial space without undue rise in interstitial tissue pressure. The role of this mechanism in hypertension and in chronic renal failure is discussed.


Management of Candida peritonitis by prolonged peritoneal lavage containing 5-fluorocytosine.

A 55 year old woman on chronic maintenance peritoneal dialysis developed Candida albicans peritonitis. This was successfully treated by continous five day peritoneal lavage containing 5-fluorocytosine. By this technique stable serum levels of the drug (58 mug/ml +/- 3.2 SEM) could be maintained. The peritoneal clearance of 5-fluorocytosine was found to be 7.5 ml/min (for peritoneal dialysis flow rate 1.2 1/hr) and the serum half-life 34 hours. The use of this drug in renal failure and its kinetics are reviewed.


Pathogenesis of malignant hypertension: experimental evidence from the renal hypertensive rat.

In rats with unilateral renal artery stenosis, the malignant phase of hypertension is characterized by: systolic blood pressure above 180-190 mm Hg; sodium and water loss; polyuria and polydipsia; markedly activated renin-angiotensin-aldosterone system; impairment of renal function and malignant nephrosclerosis in the contralateral kidney; some rats exhibit signs of cerebral hemorrhage, heart failure, acute renal failure, and some rats die. After such a phase of malignant hypertension, a period of remission may occur, which is followed by another malignant phase, etc. When malignant hypertensive rats are offered, in addition to water, saline as drinking fluid, they compulsively drink the saline, BP falls transiently, and all signs of malignant hypertension nearly or completely disappear. These observations indicate that, at a critically high BP level, it is salt and water loss which, by activating the renin-angiotensin system, trigger the vicious circle of malignant renal hypertension in rats.


General and regional hemodynamics in hypertension in chronic renal disease.

Cardiac output, total peripheral vascular resistance, renal, extrarenal, forearm muscle and skin hemodynamics and an indicator of the splanchic vascular resistance were estimated in 20 subjects with chronic renal disease without signs of chronic renal failure and without anemia. The data were compared with a group of subjects with essential hypertension. The high blood pressure of chronic renal disease of mild or moderate severity was maintained in the first place by a high cardiac output, this being due to a rise of the stroke volume, while the heart rate was only slightly increased. The total peripheral vascular resistance was within the normal range in most of the subjects. The vascular resistance in the skin was slightly raised, that in the splanchnic area and muscle unchanged in renal hypertension. The possible pathogenic mechanisms are considered.


Overhydratation and renin in hypertensive patients with terminal renal failure: a hemodynamic study.

Twenty-nine patients with terminal renal failure were treated by periodic hemodialysis for 2 to 18 months. Serial determinations of blood pressure, blood volume, cardiac output, exchangeable sodium and plasma renin activity were performed. Bilateral nephrectomy was performed in 17 patients and followed by a fall in blood pressure. Cardiac index was elevated in all patients but the blood pressure changes were mainly related to resistance changes. In non-nephrectomized patients, mean arterial pressure was directly correlated to plasma volume (P less than 0.0001), exchangeable sodium  (P less than 0.01) and plasma renin activity (P less than 0.001). In anephric patients, mean arterial pressure was only directly correlated to plasma volume (P less than o.005). The slope of the curve relating arterial pressure to plasma volume was significantly shallower in nephrectomized than in non-nephrectomized patients, indicating a lower sensitivity of pressure to volume changes. The study provides evidence that, in hypertensive patients with chronic renal failure, the positive pressure-volume relationship is the fundamental cause of the high blood pressure and that the renin-angiotensin system acts mainly by changing the sensitivity of this mechanism.


The clinical picture of renal hypertension.

Renal hypertension can usually be recognized only by examining all the features of the hypertensive illness. On the other hand, the investigation of a case of hypertension whose genesis was previously unclear can lead to the diagnosis of a hitherto unrecognized renal disease. The blood pressure values found in patients with renal hypertension are of widely differing degrees of severity. Slight rises in blood pressure (e.g. 140/90 mm Hg), can be a sign of renal disease in adolescent patients. 10-15% of the cases of chronic renal hypertension develop into malignant hypertension. High diastolic values above 120 mm Hg without renal symptomatology and without reduced renal function speak against a primary renal cause of the rise in blood pressure. The finding of hypertension developing during the course of renal disease is, with respect to the hypertensive cardiovascular complications, just as important as in the case of essential hypertension. Complications which can occur during renal hypertension include cardiac insufficiency, hypertensive encephalopathy, retinopathy, hypertensive crises and acceleration of the renal disease.


Membranous glomerulonephropathy with crescents.

A case is reported in which typical histological features of idiopathic membranous glomerulonephropathy co-existed with atypical glomeruli showing cellular epithelial crescents in addition to diffuse basement-membrane thickening. These features were seen in a renal biopsy specimen taken during rapidly progressive deterioration of renal function in a patient previously known to have mild ankle edema for four years.


Acute renal failure secondary to ureteral fungus ball obstruction in a patient with reversible deficient cell-mediated immunity.

A patient with a single functioning kidney and anuria due to ureteropelvic obstruction by a Candida fungus ball is described. During treatment with amphotericin B administered via a nephrostomy tube the drug was not detected in the serum, indicating that absorption from urothelium was not significant. Immunological studies demonstrated a lack of cell-mediated immunity which was probably brought about by a long course of prednisone and later restored when this drug was discontinued. This immunosuppression was evident even with a relatively small dosage of prednisone (5 mg daily). The literature concerning renal candidiasis and predisposing factors is reviewed.


Spinal cord injury in children.

The spinal injured child has speical needs owing to the processes of physical, mental and social growth. Goals of physical treatment programs include prevention of: genitourinary complications; contractures; pressure sores; long bone fractures, hip subluxation and dislocation; spinal deformity. Nonoperative treatment of spinal deformity employing external support should be initiated when the potential for spinal deformity exists. External support delays the development of spinal deformity, improves sitting balance and allows free upper extremity use. The overall treatment programs must consider altered body proportions, immaturity of strength and coordination. Case examples of children with spinal injury are presented above to illustrate specific problems stemming from immaturity of physical, cognitive, and social development. Spinal surgery can be a conservative measure in the growing child when there is radiologic evidence of progressive spinal deformity. Posterior spinal fusion with Harrington instrumentation and external support permits immediate return to vertical activity.


Spinal cord injury as a complication of elective anterior cervical fusion.

The true incidence of spinal cord injury as a complication of elective anterior discectomy and interbody fusion is not known. It would appear that the risk of encountering this complication increases if the surgical procedure includes instrumentation within the spinal canal. In 5 of the cases reported herein the cause for spinal cord injury was identifiable; in the remaining 5, the mechanism of injury is either obscure or not reported. All 10 patients reported had their surgery performed using the drill and dowel technique. The role of the posterior osteophyte in spondylosis and the rationale for routinely entering the spinal canal in order to decompress the spinal cord and nerve roots are examined. Since the majority of refractory disk problems that require surgery can be satisfactorily managed by discectomy and interbody fusion alone, routine instrumentation within the spinal canal may be an avoidable hazard in the majority of instances. The pathogenesis and prognosis of the anterior cord syndrome is reviewed, a possible etiology is suggested, and the anatomy, the autonomy and the importance of the anterior spinal artery system are noted. Its vulnerability in the treatment of degenerative disk disease and a possible mechanism for its occult impairment is mentioned.


Dynamic spine alloplasty (spring-loading corrective devices) after fracture and spinal cord injury.

Dynamic alloplasty in spine fractures is a method of stabilization of the fracture site of the injured spine by obtaining a steady, gradual correction of the spine in accordance with Guttman's method. Gait training may begin within 2 weeks after surgery. The method shortens the rehabilitation time of paraplegics to approximately 3 months, as compared with the conventionally treated group. Dynamic spine fitting not only enables the patient to accept his disability, take interest in vocational and social rehabilitation sooner than conventional methods, but also prevents the typical psychological and physiological complications, such as depression, neurasthenic status, urological complications and bedsores. There is no need for prolonged muscle reconditioning because the patients are immobilized only for the essential postoperative period. Following our research on "Amputations with Immediate Prosthetic Fitting," we sould like to propose the term "Immediate Functional Paraplegic Fitting" for this technique.


Biomechanical analysis of structural stability of internal fixation in fractures of the thoracolumbar spine.

Three different methods of internal fixation for the flexion-rotation thoracolumbar spinal fractures were tested biomechanically in a cadaver model for strength, mode of failure and ease of application. The compression rod system was clearly superior in strength and rotational stability to the spring device, but it was more difficult to apply than springs. The distraction rod system exhibited an intermediate level of strength with adequate rotational stability. Technically, the method is exacting and requires a clear understanding of its principle of 3 point fixation.


Rate of wear in total hip replacement.

The wear of high molecular weight polyethylene sockets was measured on radiographs, over a period of 9 to 10 years, in a group of patients whose ages averaged 73.3 years at the end of the period. The average rate of wear was 0.15 mm/year and 68 per cent of patients followed this pattern. Wear more than 2.5 mm in 10 years occurred in 15 per cent. There was a diminution in the rate of wear with the passage of time; in the second 5 years the rate of wear was approximately 40 per cent less than in the first 5 years. Body weight and physical activity did not appear to have any relationship to the final amount of wear. In a second series of very disabled subjects under 30 years of age (33 patients, 59 hips, followed only for an average of 38.4 months) the wear was rather more than in the previous series. Most remarkable was the performance of 4 patients, below the age of 50, who were considered completely normal for their age (category A); three of these wore less than the average for the main series.


Results of low friction arthroplasty in patients thirty years of age or younger.

The results of total hip replacement in 39 patients 30 years old or younger were evaluated including 67 Charnley low-friction arthroplasties and one McKee total hip arthroplasty. The average age was 25.9 years with an average follow-up of 39 months, the longest being 8 years, 3 months. The diagnoses included rheumatoid arthritis, ankylosing spondylitis, CDH, Still's disease, and a miscellaneous group. Over-all function did not improve as greatly as in the 9 to 10 year series, but this was due to a higher proportion of patients with severely disabling rheumatoid polyarthritis, hemiplegia, severe obesity, or cardiovascular disease. Wear did not seem to be any greater in this younger age group as compared to previous studies in older patients.


Physiologic emboli changes observed during total hip replacement arthroplasty. A clinical prospective study.

Fat embolism does occur with introduction of femoral components during total hip replacement arthroplasty. If massive, abrupt severe irreversible interruption of pulmonary oxygen exchange or profusion can occur. Adequate intramedullary femoral canal venting can significantly reduce the amount or dosage of fat embolism and thereby reduce and prevent primary or superimposing secondary injury of the capillary-alveolar gas exchange area within the lungs. The occurrence of fat embolism supports the mechanical theory. It also demonstrates that a patient surviving the effects of the acute mechanical pulmonary insult may still have to survive the more common and typical clinical picture of the metabolic pulmonary disease result of fat embolism that likewise can be irreversible. To prevent the occurrence of fat embolism during femoral component insertion with total hip replacement arthroplasty, the following techniques are imperative: (1) adequate femoral intramedullary canal venting; (2) maintenance of pulmonary arterial oxygen tension; (3) maintenance of blood volume.


Total hip replacement: a comparison between the transtrochanteric and posterior surgical approaches.

It can be argued with good justification, that the trochanteric complications which stimulated this study could have been avoided by strict adherence to Charnley's technique regarding trochanteric advancement and re-attachment. Should trochanteric reattachment be required, it should be done with strict attention to the details outlined by Charnley, or by use of some other device such as the Volz bolt. Trochanteric removal is usually unnecessary. The transtrochanteric approach to total hip replacement has inherent technical problems that increase the potential for complications. These problems include: painful trochanteric bursitis, displacement of trochanter, non-union of trochanter, broken wires and, an increase in dislocation rate (12% as compared to 4%). The posterior approach reduces operative time, blood loss, hospitalization, and shortens the period of time to unprotected weight bearing. Should certain conditions such as external rotation contracture, acetabular protrusion, or relative lengthening of the operated limb indicate trochanteric osteotomy, it can be accomplished readily by way of the posterior exposure.


Unicompartmental polycentric knee arthroplasty: description and preliminary results.

Unicompartmental polycentric knee arthoplasty is a procedure that we have performed in relatively few patients whose disease has not been suitable for conventional reconstruction or for total knee replacement. Preoperative and postoperative evaluations and operative technique differ little from that previously published for total knee arthroplasty. One-year follow-up of 14 knees (13 patients) reveals no major complications. These early results encourage further trial of the procedure in selected patients. Unicompartmental arthroplasty is reserved for conditions affecting predominantly one side of the joint. More specific indications are clearly defined and pertain to patients who have osteoarthritis unsuitable for valgus upper tibial osteotomy, condylar fracture and necrosis, and failure of osteotomy and tibial plateau prosthesis.


Displaced fractures of the major pelvis: a method of management.

Fractures of the bony pelvis occur with such violence that associated non-musculo-skeletal injury is common. The patients require an aggressive team approach if they are to leave the hospital alive. After the visceral injuries are treated, the bony pelvis should be aligned to minimize secondary sacroiliac arthritis. Following initial pelvic sling management, the reduction of these fractures is accomplished by using the Keim-Surcingle table coupled with a pantaloon spica cast to maintain the reduction. The patient is then managed by bedrest at home until 12 weeks post-injury at which time the plaster is removed and ambulation is progressed as tolerated. The pubic diastasis may increase if plaster immobilization is discontinued too early. We hope that an aggressive initial evaluation and team approach coupled with this method of reduction and immobilization will decrease significantly the mortality and morbidity associated with displaces fractures of the major pelvis.


Iatrogenic subcapital fracture of the hip: a new complication of intertrochanteric fractures.

A recently recognized complication of intertrochanteric fracture is a subcapital fracture occurring at the tip of the blade of an intertrochanteric fracture fixation blade plate. Histological examination reveals that this is not a fatigue fracture but is the result of stress concentration effects of a stiff metalic device. This fracture may be prevented by using a blade plate with a long blade which is well seated in the head, and by removing the metallic device as soon as it is safe to do so. Ultimate prevention lies in using a more compatible material for the internal fixation of fractures.


Rationale and indications for the "hanging hip" procudure: a clinical and experimental study.

A series of 71 patients treated by "hanging hip" procedures was followed for up to 12 years. The procedure provided a satisfactory result in patients even with severe hip joint degeneration as long as the congruity of the joint is preserved and there was no concentration of stress. When these conditions are not fulfilled the results are poor. An experimental study was carried out to try and ascertain the physiological rationale for the "healing" seen in patients with good preoperative indications. The articular cartilage of one hip in cats was denuded with a curette. This was accompanied in half the animals with a "hanging hip" procedure. The hips of the animals with "hanging hip" went onto fibrocartilaginous and chondroid healing of their articular surfaces and clinically did well. The hips of the animals who did not have multiple tenotomies developed osteoarthrosis. Full thickness cartilage defects in weight-bearing areas in adult animals are capable of functional healing if the mechanical stress on the joint is sufficiently decreased. The "hanging hip" operation should no longer be considered a salvage procedure. A physiological rationale exists for it in properly selected patients and represents a reasonable alternative to total hip replacement.


Knee morphology as a guide to knee replacement.

The complexity of knee geometry requires correct prosthesis design and size selection for the recipient. This study analyzes the morphological relationships within the knee; 16 linear anatomical parameters were measured on 30 cadaveric knees. The marginal femoral condylar contour was geometrically described by two tangent radii. Standardized radiographic techniques were developed to obtain a modified tunnel and true lateral view of the knee. Subsequently, X-rays were taken from 11 cadaver knees to achieve reproducible magnification factors. From X-rays of 53 normal subjects, 11 comparable linear dimensions were measured. The linear dimensions and condylar contour measurements were analyzed for their interrelationships by computer techniques. The width of the femur was found to be dimensionally related (correlation coefficient significant at the one per cent level) to the measured parameters with the exception of the intercondylar notch and interspinous widths. Using regression analysis, nomograms were developed to predict the linear and marginal femoral contour dimensions from the femur width. The resulting standard deviations were low, ranging from 1.0 mm for ascertaining the tibial width to 3.5 mm for determination of the femoral width at the level of the intercondylar notch. The nomograms we developed will aid the surgeon in a more precise, preoperative, morphological evaluation and may be used as a guide for future knee prosthesis design.


A jig for pin insertion in the performance of high tibial osteotomy.

The crucial step in high tibial osteotomy is to translate the computed angle of correction into a bone wedge outlined by 2 Kisrchner wires to guide the surgery. The wedge can be excised with precision in 2 planes. A jig facilitates accurate placement of the pins to correspond exactly to the predetermined angles.


Keyhole tenodesis of biceps origin at the shoulder.

A simple but efficient way to secure the biceps tendon after it has been detached at its upper end by either trauma, attrition or surgical interference is the use of the keyhole in the upper humerus. A tied or rolled knot of tendon inserted into a keyhole shaped opening in the bicipital groove permits firm attachment of the tendon to bone permitting immediate shoulder and elbow motion. Immediate postoperative joint motion avoids aggravation of coexisting shoulder disease and permits early return to work or sports. Use of this procedure in 11 patients with good to excellent results in all confirns its merit.


Epidemiology of fracture of the upper end of the humerus.

The age and sex specific indicence was calculated in 729 cases of fracture of the upper end of the humerus. The prevalence of other fractures and conditions in these patients was investigated. The age and sex specific incidence is as that of femoral neck fracture with a rapid increase with age, twice as fast in women as in men. Only fractures which include evulsion of the greater tuberosity deviate somewhat from that pattern. The more displaced fractures have a tendency to occur later in life. The prevalence of other fractures is about doubled in patients with fracture of the proximal end of the humerus as compared to age and sex matched controls. This is true for fracture of the distal end of the forearm and fracture of the upper end of the femur but also for other fractures. The prevalence of severe alcoholism was significantly greater than in controls. A history of gastric resection was in these patients about three times as frequent as in a control sample. We conclude that fracture of the upper end of the humerus must be assigned a prominent place in the category of bone fragility fractures.


Fractures of the humeral shaft: a retrospective study of 240 adult fractures.

Of 240 humeral fractures, 60 per cent occurred in patients under 35 years old, 39 per cent of fractures being in the middle third of the shaft, 28 per cent were open with an infection rate of 4 per cent. Radial nerve palsy was present in 18 per cent; midshaft fractures accounting for 69 per cent, with 60 per cent of radial nerves recovering spontaneously; 24 per cent after 12 weeks post injury. One hundred and eleven fractures had documentation greater than 3 months. Closed treatment in 100 patients resulted in 5 non-unions and 15 delayed unions; 11 primary internal fixations resulted in 3 non-unions and 2 delayed unions. Subsequent operative procedures reduced the total non-union rate to 5 per cent with 1 per cent delayed union and 4 per cent unknown. Fractures of the humeral shaft that have not begun to unite at 6 to 10 weeks probably will go on to non-union unless the treatment plan is changed. Closed methods of immobilization, other than the sling and swathe, should be used in chronic brain syndrome patients to avoid compounding their fractures. Sixty-three patients with 64 fractures were evaluated in follow-up using Cave's AEF system (92% excellent and satisfactory results) and a modification of Neer's protocol for proximal humeral fractures, (87% excellent and satisfactory results). A functional evaluation on the Cybex machine, (torque through range of motion) gave a useful graphic end result.


Treatment of thoracolumbar dislocation and fractures with paraplegia.

Ninety per cent of fractures of the dorsal lumbar spine with paraparesis or paraplegia can be best treated and reduced by closed methods when satisfactory alignment can be obtained. The pathology of the corc can thus be allowed to regress and recover if it will do so. Strict posturing techniques are the most important part of medical and nursing care. Approximately 10 per cent of the cases can be treated by gentle, active surgical techniques such as manipulation under general anesthesia or open reduction. The use of spinal rods and clamps is rarely indicated. Surgical techniques may be advisable later for treatment of non-union with spinal stenosis and failure to improve.


Lysozyme in calcifying tissues.

Lysozyme, present in several connective tissues, is synthesized in cartilage by chondrocytes and immediately secreted into the extracellular matrix, where it is bound in the territorial (lacunar) matrix and along collagen fibers. In the epiphyseal growth plate, lysozyme levels increase toward the cartilage-bone junction, but cartilage lysozyme seems to be bound or inactivated by an inhibitor. Parathyroid extract injections decrease bone lysozyme levels. Cartilage lysozyme levels are low in rickets, while vitamin D increases it in both cartilage and aorta, suggesting an association between lysozyme and the calcification process. Although it is cationic and forms salt-like complexes with cartilage proteoglycans and chondroitin sulfate in vitro, lysozyme does not seem to be bound to proteoglycans in the native tissue. Proteoglycans in cartilage exist in a monomeric and aggregated form. Aggregation occurs by an interaction of monomers with hyaluronic acid and spedific link proteins. Aggregated proteoglycans inhibit mineral accretion in vitro. Mammalian cartilage lysozyme but not hen egg white lysozyme seems to inactivate this inhibitory capacity of aggregated proteoglycans, which is probably due to an interaction with hyaluronic acid resulting in a disaggregation. Therefore, we hypothesize that cartilage lysozyme plays an important role in the regulation and initiation of cartilage calcification.


Laboratory evaluation of a metal-plastic type of metacarpophalangeal joint prosthesis.

In the normal joint, the conformity of the joint surfaces can provide appreciable dorsal-volar shear stability when a compressive joint force acts. The centers of rotation were within 3 mm of the center of the metacarpal ball. Passive radial-ulna motion at 0 degrees flexion was close to 60 degrees, active motion being half of this; at 90 degrees flexion, there was 37 degrees passive and 23 degrees active motion. Studies of canal shapes and sizes showed that a transverse section deviated from circular by 1-2.5 mm; longitudinal sections were trumpet-shaped but had waves and ripples of about 0.5 mm. This is relevant to cement fixation. A metal-plastic prosthesis was tested in positions and with forces considered applicable to arthritics. It is possible that with plastic components, permanent deformation will progressively occur. The pull-out strength between cement and bone in cadaver bones was about 100 kg; metal stems in cement pulled out at about 50 kg, and plastic stems at 10-20 kg. Slippery stems pulled out at much lower values.


The ultrastructure and biomechanical significance of the tidemark of articular cartilage.

Thirty specimens of human articular cartilage obtained at surgery were examined by scanning electron microscopy to determine the ultrastructure of the tidemark, the junction of the non-calcified and calcified portions of mature articular cartilage. Three distinct variations of the collagen framework of the tidemark were observed: (1) A band of randomly oriented compacted fibrils that appeared to be continuous with those of the non-calcified and calcified zones. (2) A band of flattened fibrils paralleling the undulating surface of the calcified cartilage. (3) A band of perpendicularly oriented fibrils having a distinct continuous transition between the non-calcified and calcified zones, the amount of calcified material applied about the fibrils rapidly increasing as the fibrils entered the calcified zone. The tidemark may serve to provide a tethering mechanism for the relatively flexible and perpendicularly oriented collagen fibrils of the deepest portion of the non-calcified articular cartilage and may prevent them from being sheared at their point of anchorage to the calcified zone. The undulating pattern of the tidemark affords a strong geometric pattern in providing resistance to the shearing action of articulation. Small gaps present in the tidemark may provide pathways for the passage of nutrients into the deep non-calcified zone of articular cartilage from the subchondral bone.


The management of long bone fracture in the spinal cord injured patient.

Principles of management of long bone fractures in patients with spinal cord injuries vary with the type of fracture and duration of quadriplegia. Class I fractures (acute injuries) are managed by existing principles of long bone fracture management with a tendency to open reduction and internal fixation to dispense with the necessity of plaster casts on insensate skin. Class II fractures (pathologic--osteoporotic) heal well, require minimal specific treatment, and open reduction is usually contraindicated. Class III fractures (acute injuries in chronic paraplegia) are treated with methods least likely to disrupt the patient's life style in a wheelchair. Open reduction should be used whenever there are difficulties with circular casts and traction methods.


Urological management of the traumatic cord bladder.

Time and patience are the two prerequisites for treatment of the traumatic cord bladder. The experienced physician knows when early intervention is necessary. Intermittent catheterization from onset of injury is as of today the accepted method of treatment in most large centers over the world. "Lack of personnel" is the usual answer where this procedure is not being carried out. Administrative people do not realize that with this method the patients can be discharged more quickly and have less complications; complications lead to a great variety of surgery, which is costly to any institution. And above all, what is best for the patient should always be our goal. Medicine travels fast these days; therefore, physicians must keep an "open mind" for the newer developments. The ileal conduit and the cutaneous vesicostomy have their place in the armamentarium of the treatment of the traumatic cord bladder: the proponents should make a greater effort to create more spedific indications. It will be interesting to see what the results of suprapubic needling will produce. Electrical stimulation is still in a research stage. The latter two methods have a noble goal, i.e., prevention of infection. Experience with chronic bladder infection over the past 28 years suggests that the majority of our patients possibly may survive because of "local tissue immunity." The ultimate solution is a presently unknown preventative method of treatment of chronic urinary tract infection.


Spasticity following spinal cord injury.

Spasticity is a hyper-excitable state of the reflex arcs in the spinal cord below the level of injury. Not only is the skeletal motor system affected, but bladder, bowel, blood pressure, and erection reflex mechanisms are also involved. Spasticity gradually emerges from the initial phase of spinal shock one to two months after the injury, and usually reaches a plateau of a mild to moderate degree in 3 to 4 months. Neurophysiological mechanisms indicate an increase in the alpha and gamma reflex systems and that central excitability through the interneurons is also involved in these systems. Excessive spasticity should be recognized as a substitute for pain in the spinal cord injured patient, as infections, calculi, pressure ulcers, and other normally painful conditions set off the hyper-sensitive reflexes causing more spasticity. Education and health maintenance is the best prevention of severe spasticity. Definitive treatment of incapacitating spasticity is to find and treat the underlying disease condition, as well as to introduce medication which will also suppress the spasm (Valium and/or Dantrolene). Muscle motor points and/or nerve blocks with neurolytic agents is perhaps the best technique for quietening excessive spasticity. Intrathecal neurolytic agents, anterior or posterior rhizotomies and cordectomies are not advocated even in severe incapacitating spasticity as they are too destructive. Selective longitudinal myelotomy is by far the best surgical technique for disrupting excessive spasticity, if any such procedure is to be done. Tendonotomies may be necessary in chronic contractures of joints after the muscle spasticity has been reduced. Excessive spasticity is not regarded as a normal state in the spinal cord injured patient. The cause should be sought and treated. Nerve destruction techniques should not be used unless medical and nursing techniques have failed. Prevention is so important and can be achieved by education, health maintenance, and especially motivation.


Pain and suffereing following spinal cord injury.

It is important to distinguish between the part played by possible pathological processes which can cause pain and those emotional problems which are often somatosized as pain. So much depends upon the patient's own ability to cope with his problem and communicate them effectively. The acceptance of his disability and of the strange feelings where once he felt his body has to take place. There is often a long period of time and experiences that the patient has to go through before he accepts the reality that he is paralyzed permanently and that he has to make a life that is worthwhile.


Pressure sores: classification and management.

Four grades of pressure can be recognized on the basis of pathophysiology of soft tissue breakdown overlying bony prominences. Management is correlated with the extent of the lesion and ranges from local wound care, turning and systemic support for Grade I and II, to local and radical excision with soft tissue flap closure for the more extensive Grades III and IV.


Diagnosis and prognosis of acute cervical spinal cord injury.

The diagnosis of complete or incomplete quadriplegia and designation of functional levels can be accurately determined during the first 24 hours after injury in virtually all cases of severe traumatic quadriplegia. The prognosis for recovery depends upon an understanding of regeneration of nerve roots following injury and the significance of return of involuntary reflex activity. A realistic prognosis and accurate evaluation of various forms of treatment depend upon accurate documentation of the pattern of sensory and motor deficits.


Compartmental syndromes in peripheral vascular surgery.

The need to relieve muscle swelling and secondary vascular impairment of an extremity may occur following a variety of conditions. Regardless of the type of insult, massive swelling of an extremity can result in ischemic necrosis of muscle as a result of tamponade produced by restrictive circulferential fascia. When intracompartmental pressure approaches or exceeds arterial pressure, a portion or the entire extremity may be in jeopardy. Fasciotomy is one of the most important adjunctive procedures available to assure survival of an extremity with altered distal circulation resulting from massive swelling. Its importance has been stressed infrequently in the literature. The indications for its use are outlined in a variety of clinical situations. The proper techniques have few complications and much to offer with regard to limb salvage and reduction of morbidity. Fasciotomy does not preclude correction of the underlying cause for restrictive muscle tamponade when possible, nor can it be expected to reverse well established ischemia. Early and liberal use of fasciotomy is advocated when the outlined indications prevail.


Chondrosarcoma of the hand arising from a pre-existent benign solitary enchondroma.

Chondrosarcomas of the hand are relatively rare. Chondrosarcomas may arise by malignant transformation of a pre-existing enchondroma, but this causal relationship has been difficult to establish in solitary enchondroma. This is a case report of a chondrosarcoma of the proximal phalanx of the right index finger in a 66-year-old woman demonstrating histologic evidence of malignant transformation of a pre-existent benign solitaary enchondroma. Careful analysis of the preoperative X-ray for punctate endosteal calcification or cortical expansion and ample histologic sampling of the endosteal component of chondrosarcomas arising from within bone may demonstrate a greater incidence of preexistent enchondroma.


False aneurysm of the left external iliac artery following total hip arthroplasty.

This is a report of a case of false aneurysm of the external iliac artery associated with pre-existing bone irradiation necrosis and postoperative infection of a total hip replacement arthroplasty in a 77-year-old woman. Vascular injury, when it does occur, requires prompt recognition, proper exposure and adequate treatment while techniques of primary suture should be used for closure of most defects, extensive ligation, resection and grafting procedures may be required in certain instances to control hemorrhage and maintain necessary circulation. The most important factors are an awareness of the likelihood of vascular pathology prior to surgery and the importance of angiographic examination in any patient in whom suspicion of such defects exists.


The effect of increased tissue pressure on blood flow.

Theoretical consideration of the factors involved in maintaining vascular equilibrium and experimental evidence in animals and man indicate that at high tissue pressures there may be a sharp decline in blood flow and, in certain situations, complete cessation of blood flow even at tissue pressures below mean arterial pressure. At least two mechanisms appear to be involved: active closure of small arterioles under vasomotor tone when transmural pressure is lowered, either by falls in intravascular pressure or rises in tissue pressure, and passive collapse of soft-walled capillaries when tissue pressure rises above intracapillary pressure. These mechanisms are likely to assume particular importance when tissues are surrounded by non-compliant fascia and may thus be involved in compartmental syndromes.


Osteoid-osteoma of the spine with localization aided by 99 mTc-polyphosphate bone scan. Case report.

This is a case report of a 13-year-old boy with an osteoid-osteoma located in the pedicle of the third lumbar vertebra. The lesion could not be visualized on routine roentgenograms but with the use of technetium polyphosphate bone scan as a guide a suggestive bone lesion was found with tomograms. Histologic examination confirmed the diagnosis of osteoid-osteoma. This case illustrates the value of skeletal scanning in occult bone lesions.


False aneurysm of the brachial artery complicating closed fracture of the humerus. A case report.

A 66-year-old, obese, mentally retarded man sustained a closed spiral fracture of the humerus accompanied by development of a large false aneurysm arising from a small rent in the distal third of the brachial artery. Because of the patient's body habitus, mental deficiency, and paucity of objective physical findings, the arterial injury was not suspected until expensive pressure necrosis necessitated shoulder disarticulation as a lifesaving measure. Although false aneurysms are known to complicate penetrating trauma and various surgical procedures using metallic implants, the lesion has not been previously reported with closed long bone fractures. The authors wish to alert others to occurrence of the occult arterial injury in association with a relatively common extremity fracture. The need to exercise special awareness and suspicion of subtle injuries in patients whose age, mental status, or associated trauma render communication of symptoms impossible, cannot be overemphasized.


Closed rupture of the anterior tibial tendon. A case report and review of the literature.

Closed rupture of the anterior tibial tendon is an unusual injury. It occurs in middle-aged to elderly males following forced plantar flexion of the ankle. A case is presented of a 69-year-old man with spondylolisthesis whose tendon ruptured during a physical examination. The injury was thought initially to represent an acute L5 root compression secondary to a herniated intervertebral disc at the level of his spondylolisthesis. The correct diagnosis was made after admission to the hospital. Surgical repair of the tendon resulted in normal ankle motion and strength. A review of the 12 previously reported cases indicates that treatment has been either surgical repair or conservative management. All patients recovered a normal gait but those treated surgically had more motion and dorsiflexion strength. This condition emphasizes the importance of exact history taking and thorough physical examination.


Flexor digitorum accessorius longus.

A supernumerary muscle in the ankle joint, the flexor digitorum accessorius longus, was found in 12 of 100 cadavers (12%). The muscle originated either by 2 heads (a long and a short one) or by a single head, from any of the deep structures of the posterior compartment of the leg. It descended in the tarsal tunnel, superficially and close to the neurovascular bundle and to the tendon of the Flexor hallucis longus muscle, to insert into the tendon of the Flexor digitorus longus in the planta. During this course, the muscle very frequently preserved its fleshy fibers, and could easily be identified by this characteristic. The possibility of such a muscle being a factor of compression in a "tarsal tunnel syndrome" should be kept in mind.


Good Samaritan cervical traction.

By means of a unique method, cervical traction can be maintained uninterruptedly and comfortably while the patient is free to choose any position he wishes from flat to upright in bed.


Differentiation of cartilage from calvarial bone under the influence of bone matrix gelatin in vitro.

Fetal rat calvarium in an optimum (CMRL-1066) culture medium (with respect to amino acids. Tween 80, DNA precursors and hydrogen acceptors used in oxidative metabolism) produces new lamellar bone. The explanted osteoprogenitor cells survive, proliferate on living membrane bone surfaces and remodel membrane bone into lamellar bone. In the same culture medium, calvarial connective tissue and osteoprogenitor cells grow out of the membrane bone interstices onto a substratum consisting of bone matrix gelatin (BMG) and differentiate not into bone but into hyaline cartilage. Outgrowths from either bone or muscle onto a substratum of BMG prepared from bone autodigested in neutral buffer solutions, produce only fibrous connective tissue. In BGJ, a culture medium containing suboptimal ingredients for cell proliferation, calvarial bone produces neither lamellar bone nor new cartilage but is gradually resorbed and replaced by fibroblasts. In CMRL culture medium, outgrowths of mesenchymal-like cells from muscle onto a substratum of living membrane bone produce an epiphyseal plate-like columnar deposit of new hyaline cartilage. These observations suggest that the function of BMG is to evoke mesenchymal cell differentiation into prechondroblasts during the latent or migratory morphogenetic phase while the effect of the culture medium is to provide the bionutritional requirements for synthesis of hyaline cartilage matrix by chondrocytes during the patent phase of development.


The etiology of steroid-induced avascular necrosis of bone. A laboratory and clinical study.

An attempt was made to reproduce in the experimental animal the clinical condition of steroid induced avascular necrosis of bone. There was a decrease in the ability of subchondral osteocytes to metabolize H3 cytidine and an increased amount of cell death as indicated by the number of empty subchondral lacunae. Oil red O stain for intravascular fat demonstrated large accumulations of fat in subchondral vessels. Much of this fat was deformed and was surrounded by reticulin, leading to the conclusion that it was embolic. A study of human material showed intravascular fat and diminished number of osteocytes in patients on systemic steroids who had died without clinical evidence of avascular necrosis. In addition, intravascular fat was demonstrated in avascular femoral heads and humeral heads both from transplant patients and patients receiving steroids for other reasons. The most tenable explanation for this series of events involves steroid-induced fatty liver with subsequent showeres of fatty emboli, which lodge in the subchondral region owing to the microvascular anatomy. Cell death ensues, and the necrotic bone is partially removed by the normal resorptive mechanism, but steroids retard osteogenesis, lead to microfractures, and eventually sequester the involved area.


The antimicrobial properties of povidone-iodine methylmethacrylate complex. A preliminary report.

The incorporation of povidone-iodine into polymethylmethacrylate was found to inhibit the growth of coagulase-positive Staphylococcus aureus in vitro.


The use of muscle stimulation for inducing scoliotic curves. A preliminary report.

Based on a clarification of the anatomical mechanisms involved in the lateral stability of the spine, electrical stimulation was applied unilaterally to paraspinal muscles of 20 growing dogs in an attempt to produce thoracic scoliotic curves. These experiments were considered critical in the development of a new procedure for correcting human scoliosis. Various alternating voltages and wave forms were used. The curvature varied with the voltage applied, frequency being maintained at a constant value. Curves can be developed in the spines of normal dogs by unilateral electronic muscle stimulation without clinical discomfort or significant muscle atrophy. Curves always develop in the predicted direction (concave to stimulation). Stimulation of more than 4-6 weeks produced curves with significant wedging and rotational deformation. In one experiment curves created in one direction were reversed by stimulating opposite side musculature. Because of the similarity of human and canine anatomy, the results obtained gave impetus to further experimentation with human application. Electromyographic tests, biopsy studies, direct deformation measurements of post mortem dissections and weekly X-rays substantiate the above observations.


Prevention of knee instability. Experimental model for prosthetic anterior cruciate ligament.

Loss of the anterior cruciate ligament (ACL) in the dog results in a predictable type of arthritis. This condition can be prevented by successful prosthetic substitution of the anterior cruciate ligament (ACL). The condition is a practical model, and a sensitive index of success and failure for evaluation of prototype prostheses. Changes in the joint can be differentiated on the basis of cruciate insufficiency and reaction to the synthetic implant. The model was defined by replacing the ACL with a mesh or tape Dacron prosthesis in 16 Beagle dogs. Gait and anterior drawer sign are unreliable parameters of ACL insufficiency in dogs. At sacrifice up to 3 years postoperatively, 8 joints out of 32 joints were without arthritic changes. Arthritis developed in all joints in which the prosthesis elongated or broke. Failure always occurred intra-articularly at the mouth of a bone tunnel. Successes were inconsistent even with a single material and animal breed. The drillhole techniques used in ACL reconstructions are difficult to standardize. Variability in placement of the prosthesis is compounded by cutting action of bone edges. Porous mesh did not provide a lattice for true ligament regeneration through the joint. Fixation was not a problem in this series.