Effects of pregnancy and contraceptive steroids on gallbladder function

We used real-time ultrasonography to study gallbladder kinetics in 11 nonpregnant women, 17 women using steroid contraceptives, and 33 pregnant women. Gallbladder volume was determined after an overnight fast and serially for 90 minutes after a standard liquid meal. After the first trimester of pregnancy, gallbladder volume during fasting and residual volume after contraction were twice as large as in control subjects. The rate of emptying and the percentage emptied were reduced. In early pregnancy the only important abnormality was a 30 per cent decrease in emptying rate. Gallbladder function was not affected by contraceptive steroids. Incomplete empyting of the gallbladder in late pregnancy leaves a large residual volume and may cause retention of cholesterol crystals, a prerequisite for cholesterol-gallstone formation. These findings are consistent with the view that pregnancy increases the risk of cholesterol gallstones. The increased incidence of gallstones associated with contraceptive steroids does not involve abnormal gallbladder kinetics.

The effects of thioureylene compounds (goitrogens) on lactoperoxidase activity

The rates of oxidation of several goitrogens by lactoperoxidase and the rates of inactivation of lactoperoxidase by the same goitrogens have been measured. The influence of iodide on both reactions has also been evaluated. It has been shown by us that iodide acts catalytically in regulating lactoperoxidase activity at pH 8.8. The rate data have been analyzed by a computer program which solves the differential equations for the above mentioned reactions. From this computer analysis we have been able to obtain binding constants of the goitrogens and inactivation rate constants of lactoperoxidase. Iodide was shown to inhibit goitrogenic activity either by increasing the rate of drug oxidation or by reducing the rate of enzyme inactivation, or both, depending on the particular drug. Iodide had little or no effect on the goitrogen-binding constants. We have also shown that the relative rates of enzyme inactivation can be correlated with the potency of the goitrogen as an antithyroid drug.

B-mode echoencephalography in the normal and high risk infant

Commercially available high resolution, contact, gray scale imaging systems can now dependably visualize the normal and abnormal ventricular system as well as some other intracranial structures in all newborns. On 25 normal infants and 41 high risk infants, 135 B-mode echoencephalograms were performed. The technique for obtaining these scans is described. The normal lateral ventricle at the midbody in term infants is 0.9--1.3 cm wide (mean, 1.1 cm). Normal ratio of lateral ventricle to hemisphere is 28% (range, 24%--30%). High risk premature infants have a ratio of 31% (range, 24%--34%). The demonstration of hydrocephalus and cystic intracranial masses is reliable and the correlation with computed tomography is excellent. Postoperative or high risk infants can be repeatedly evaluated without radiation, at a lower cost, and more rapidly with ultrasound than with computed tomography. Ventricular size can be closely monitored and shunt failure detected at any early stage.

The initial evaluation of the patient with multiple injuries

The management of trauma patients requires organization and the cooperation of trained health personnel, beginning at the site of injury and continuing until the patient is discharged from the hospital. Treatment guidelines and priorities must be well outlined in advance to provide optimal care and minimize delay prior to definitive therapy. Resuscitation and treatment must begin immediately and simultaneously following well established principles. These guidelines and the general care of the patient with multiple trauma are discussed in this article.

Iodide binding and regulation of lactoperoxidase activity toward thyroid goitrogens

The effects of the antithyroid goitrogens, methylthiouracil and methylmercaptoimidazole, on the oxidation of N-acetyltyrosylamide at pH 8.8 by lactoperoxidase have been evaluated in the presence and the absence of iodide for the purpose of elucidating the effects of iodide. At pH 8.8, iodine is not oxidized. In the absence of iodide, the two antithyroid drugs inactivate lactoperoxidase by a second order process. When iodide is added before methylthiouracil or methylmercaptoimidazole, enzyme inactivation does not occur as rapidly and both goitrogens are readily oxidized. The kinetics of the oxidation reactions have been analyzed in order to obtain the equilibrium constant of the iodide . lactoperoxidase complex. Essentially the same iodide dissociation constant, i.e. 2 x 10(-5) M, was found by studying its effects on the kinetics of oxidation of the two antithyroid drugs. A large difference absorption spectrum is observed in the Soret region between native lactoperoxidase and lactoperoxidase inactivated by methylthiouracil.

Critical micelle concentrations of gangliosides

The micellar properties of mixed, bovine gangliosides and purified galactosyl-N-acetylacetylgalactosaminyl (N-acetylneuraminyl) galactosylglucosylceramide were studied by gel filtration, equilibrium dialysis, and band and boundary centrifugation in sucrose gradients. The dissociation of micelles is very slow (days) in water and required us to approach equilibrium by association of monomers rather than by the dissociation of micelles. The gangliosides were therefore first converted into very low molecular weight aggregates (1-3 molecules) by dissolving them in Me2SO. Galactosyl-N-acetylgalactosaminyl(N-acetylneuraminyl)galactosylglucosylceramide was then diluted into aqueous sucrose gradients and sedimented by the boundary centrifugation technique. This gave a sedimenting micelle and a nonsedimenting monomer concentration of (1-2) x 10-10 M (or less) which corresponds to the critical micelle concentration value. The mixed gangliosides revealed two micellar sizes (i.e., 10 and 4.5 S), the slower sedimenting species being formed from the larger one with time (days). The critical micelle concentration of the mixed gangliosides was found to be approximately 10-8 M by a gel filtration, equilibrium dialysis, and band centrifugation.

Left ventricular outflow obstruction produced by a pedunculated fibroma in a newborn: clinical, angiographic, echocardiographic and surgical observations

An unusual case of a one-day-old infant with significant left ventricular outflow obstruction produced by a pedunculated fibroma is described. The clinical findings were indistinguishable from severe valvular or subvalvular aortic stenosis. The tumor was difficult to detect by echocardiography. It produced an echo-free widening of the left ventricular outflow tract. Left ventricular cineangiography clearly demonstrated a mobile mass beneath the aortic valve.

Ultrasonic evaluation of the pancreas

With the advent of new gray scale imaging techniques, ultrasound plays a major role in the diagnosis of pancreatic lesions. As a noninvasive, nonionizing, accurate, and inexpensive diagnostic modality that directly images the pancreatic gland, ultrasound can be used as a primary screening tool. It is helpful in confirming the diagnosis of acute pancreatitis and in detecting and following pseudocysts and other complications. Neoplasms can be detected with a high rate of accuracy, and by assessing the presence of ascites or metastatic foci in the liver, ultrasound can aid in the staging of the neoplastic process. Bowel gas and obesity remain serious limitations to adequate examination, and in these patients computed tomography offers a complementary modality.

Subunit association and heterogeneity of Limulus polyphemus hemocyanin

The molecular weights of the 6S, 24S, 36S, and 60S components of Limulus polyphemus hemocyanin were determined by high speed sedimentation equilibrium to be 69 400, 856 000, 1 690 000, and 3 160 000. The behavior of this hemocyanin appears to be similar to that of other arthropod hemocyanins where the first aggregation step is the formation of a hexamer of the 6S monomer. Here the larger aggregated states (24S, 36S, and 60S) are successive dimers of an unobserved hexamer (16S). The 24S-36S-60S association was found to be heterogeneous, suggesting that 24S components of different composition may be present.

Effects of Hofmeister salts on the self-association of glucagon

The trimerization constants of glucagon at pH 10.6 in 0.76 M K2HPO4 have been calculated from circular dichroism data between 5 and 50 degrees C. The free energy, enthalpy, and entropy of transfer have been evaluated from the current results and published data in 0.20 M phosphate. The free energies of transfer are derived completely from an increase in the entropy of transfer, since the enthalpy of transfer is less favorable at all temperatures. These parameters are compared with those of various model groups and compounds: CH2, peptide, methane, ethane, and the 1--13 N-terminal fragments of ribonuclease. The effects of fluoride and chloride on the self-association of glucagon have been compared with that of phosphate at 25 degrees C. These effects are consistent with the binding of approximately one molecule of salt to the trimer and a systematic decrease in the number of water molecules bound to the trimer compared to the monomer for the series K2HPO4, KF, and KCl.

Physical, emotional and social adjustments to home dialysis

Forty home dialysis patients and their families were interviewed by means of a standard questionnaire to determine their physical, emotional, and social adjustment to treatment. The results indicated a reasonable level of health, particularly in patients under the age of 50 years. However, home dialysis produced considerable strain in the family, particularly in the dialysis partners. Home training programmes should provide appropriate learning and technical experience for the dialysis partners and continued support, including integrated medical and paramedical services, domiciliary visiting, and regular holidays. Limited-care dialysis facilities should be provided where home dialysis is impractical or becomes intolerable.

Self-association of glucagon as measured by the optical properties of rhodamine 6G

The fluorescence of rhodamine 6G is completely quenched in glucagon solutions in 0.6 M K2HOP4 at pH 10.6. The absorption of rhodamine 6G is red-shifted by the same reaction. A single rhodamine 6G molecule appears to be bound to a hydrophobic patch in the center of the trimer of glucagon. Since the glucagon monomer has almost no organized structure this site exists only in the associated trimer form of glucagon. The self-association of glucagon to the trimer has been determined from the variation in rhodamine 6G fluorescence and absorption measured over a 60-fold range of dye concentration. The self-association constant agrees with values determined by other methods in the absence of dye. The binding isotherms of rhodamine 6G to glucagon shift with glucagon concentration and exhibit negative cooperativity.

Percutaneous nephrostomy: a series and review of the literature

A series of 53 percutaneous nephrostomies and a literature review of 516 such procedures are presented. The selection of patients with supravesical urinary obstruction, urinary fistulas, and renal calculi is discussed, and the concept is advanced that percutaneous nephrostomy is more than a temporizing preoperative procedure. The available techniques are compared; modified instrumentation for balloon catheter insertion, a combination of fluoroscopic with real-time ultrasound guidance, and some additional principles of subsequent management are introduced. Successful results can be expected in over 90% of percutaneous nephrostomies, with major complications limited to 4% and minor complications to 15%. The limitations of percutaneous nephrostomy and the role of surgical nephrostomy are discussed.

New health practitioners and dermatology manpower planning

To assess the need for dermatologists in the United States, the potential role of new health practitioners in this specialty is considered. Available data on physician extenders in general and informed opinion on dermatologist extenders in particular suggest that specially trained, nonphysician personnel could substantially augment the supply of dermatological services. At present, however, widespread adoption of new staffing patterns appears unlikely. A long-run trend toward greater use of all categories of ancillary personnel in this specialty is expected, and the profession is urged to play an early and active role in this trend's development.

Thermodynamics of the self-association of glucagon

In water, glucagon exists in an equilibrium between a trimer in which more than half of the peptide groups are in an alpha-helical configuration and a monomer which has a random coil configuration with few alpha-helical residues. The thermodynamics of this self-association have been evaluated by studying the temperature- and concentration-dependence of the mean residue ellipticity at 220 nm. The enthalpy and entropy changes of association were negative at all temperatures between 5 degrees and 50 degrees and had large negative temperature dependencies. Usually an association that involves nonpolar groups is considered to be driven by a positive entropy term. Such an explanation is not tenable in the case of glucagon. However, if the effects of nonpolar groups on the coil-to-helix transition of a polypeptide are included into the thermodynamic considerations of hydrophobic interactions, then the negative parameters observed for glucagon association can be readily understood. The hydrophobic interaction is therefore not necessarily controlled by the entropy change because, if there are significant conformational changes, the reaction may be controlled by the enthalpy change. Consequently, the more important parameter characteristic of all hydrophobic reactions is the heat capacity change.

Utilization of physician services for dermatologic complaints. The United States, 1974

The National Ambulatory Medical Care Survey provides data on the "who," "for what complaint," and "to whom" for office visits to office-based physicians. In 1974, complaints referable to the skin accounted for 44 million physicians visits. This represents 7% of the 634 million visits to physician offices made during this period. Dermatologists accounted for 34% of all visits for skin complaints. General and family practitioners accounted for 40% of such encounters. Office visits prompted by dermatologic complaints were frequently less than 16 minutes long. Each office-based dermatologist accounted for an average of 5,600 patient visit per year. According to the dermatologist's diagnosis, 31% of these visits were prompted by acne; warts accounted for an additional 8%.

Effect of corticosteroids on collagen synthesis

Contraction and epithelization are two phenomena of "wound healing" retarded by corticosteroids. It is unclear how these agents affect collagen synthesis and wound remodeling. The methods used by several authors to conclude that steroids inhibit collagen synthesis are questioned. Therefore, collagen synthesis was measured in cultured steroid-treated chick embryo calvaria, 5 day open wounds in treated rats, and intralesionally injected human keloids. Collagen synthesis was suppressed only by long-term administration of massive systemic doses of a sustained release form of methylprednisolone (Depo-Medrol). Large, intermittent doses of corticosteroids (triamcinolone and Solu-Medrol) did not alter collagen synthesis. Because human keloids become softer and smaller following intralesional administration of triamcinolone without lowering the normally high rate of collagen synthesis, we hypothesize that corticosteroids enhance collagen degradation.

Resolvability of Adair constants from oxygenation curves measured at low hemoglobin concentration

Analyses of low concentration oxygenation curves for apparent Adair constants in which the effects of dimers is ignored have been explored using recently determined values of the overall energy coupling parameters. For high affinity systems and favorable energy distributions, it is found that the errors in estimated binding free energies may be less than one kcal provided the measurement errors are strictly random and of small magnitude. These errors are nevertheless quite substantial as compared with the differences between values for the successive binding steps.

Two-dimensional echocardiographic assessment of vegetative endocarditis

Real-time, two-dimensional echocardiography was used to document the presence and assess the size and location of vegetative lesions of the cardiac valves and chambers in seven patients with bacterial endocarditis. Anatomic correlation (surgical or autopsy) was accurate in all patients. Two-dimensional echocardiography was shown to be of particular value in determining morphologic characteristics of the lesions since this technique provides spatial information concerning moving cardiac structures. The results of two-dimensional echocardiography were most helpful in determining selected aspects of the clinical care provided for each patient. These data demonstrate that real-time, two-dimensional echocardiography, in combination with M-mode imaging techniques, may be of great potential value in the detection of vegetative endocarditis. Furthermore, reliable assessment of lesion size and location may, in time, become a valuable method for following the morphologic changes that occur in vegetative lesions, and thus determine the efficacy of antibiotic therapy. This information may also provide a means for evaluating certain patients for surgical intervention.

Oxygenation-linked subunit interactions in human hemoglobin: analysis of linkage functions for constituent energy terms

Resolution of the linkage functions between oxygenation and subunit association-dissociation equilibria in human hemoglobin into the constituent microscopic terms has been explored by numerical simulation and least-squares analysis. The correlation properties between parameters has been studied using several choices of parameter sets in order to optimize resolution. It is found that, with currently available levels of experimental precision and ranges of variables, neither linkage function can provide sufficient resolution of all the desired energy terms. The most difficult quantities to resolve always include the dimer-tetramer association constant for unliganded hemoglobin and the oxygen binding constants to alphabeta dimers. A feasible experimental strategy for overcoming these difficulties lies in independent determination of the dimer-tetramer association constants for unliganded and fully oxygenated hemoglobin. These constants, in combination with the median lignad concentration, provide an estimate of the energy for total oxygenation of tetramers which is essentially independent of the other constituent energies. It is shown that if these separately determinable parameters are fixed, the remaining terms may be estimated to good accuracy using data which represents either linkage function. In general it is desirable to combine information from both types of experimental quantities. A previous paper (Mills, F.C., Johnson, M.L., and Ackers, G.K. (1976), Biochemestry, 15, the preceding paper in this issue) describes the experimental implementation of this strategy.

Oxygenation-linked subunit interactions in human hemoglobin: experimental studies on the concentration dependence of oxygenation curves

An experimental study on the concentration dependence of oxygenation curves for human hemoglobin has been carried out between 4 X 10(-8) M heme and 5 X 10(-4) M heme in 0.1 M tris(hydroxymehtyl)aminomethane hydrochloride, 0.1 M NaCl, 1 mM disodium ethylenediaminetetraacetic acid, pH 7.4, 21.5 degrees C. With decreasing hemoglobin concentration the curves show pronounced shifts in position and shape, consistent with dissociation of tetrameric hemoglobin into dimeric species of high affinity and low cooperativity. Combination of these data with independently determined values of dissociation constants for unliganded and fully liganded hemoglobin permits a resolution of the seven parameters necessary to define the linked binding and subunit association processes. The total oxygenation-linked subunit dissociation energy (6.34 kcal) was resolved into intersubunit contact energy changes between alphabeta dimers in tetrameric hemoglobin which accompany binding of the first, middle two, and last oxygen molecules. The resolution is accurate to within approximately +/-0.3 kcal. To within this limit the isolated dimers are found to bind oxygen noncooperatively and with the same affinity as isolated alpha and beta chains. Equally good fits to the data are obtained when dimers are slightly anticooperative. At least three major energetic states are apparently assumed by hemoglobin tetramers, with respect to the alpha1beta2 contact region, corresponding to (a) unliganded, (b) singly liganded, (c) triply and quadruply liganded species. The results do not establish whether these states may be assumed by a single molecule, or whether they arise as averages over a distrubution of conformational states. They do provide unequivocal evidence against a concerted transition at any particular binding step in a system with only two energetic states of tetramer (i.e., an all or none switchover between T and R states at a particular binding step).

Numerical study of the Johnston-Ogston effect in two-component systems

Numerical solutions of the Lamm equation are presented for systems exhibiting the Johnston--Ogston effect. From these solutions it is apparent that the movement of the maxima of the concentration gradient curves reflects the sedimentation velocity of the slow or fast components in their appropriate plateaus. A simple generalization of the Johnston--Ogston analysis is presented, valid for all centrifugation times in a radial field and sector shaped cell provided only that there exist both a plateau of the slow component by itself and the mixed plateau with both slow and fast components present.

Kinetics of deoxyhemoglobin subunit dissociation determined by haptoglobin binding: estimation of the equilibrium constant from forward and reverse rates

Deoxyhemoglobin tetramers dissociate into dimers very slowly, with half-times on the order of several hours. It is demonstrated that absorbance changes in the Soret region which accompany this dissociation and persist upon binding of haptoglobin 1-1 to the dissociated dimers can be used for accurate kinetic determinations over the necessarily long periods required for study. This method of study for the slow reactions depends upon long-term spectral integrity of the reaction mixtures and upon accurate measurement. The variation in rate constants determined by this procedure has been correlated with variations in structural constraints at the dimer-dimer contact region. In the presence of 2,3-diphosphoglycerate the rate constant is decreased, consistent with the role of this effector in binding to both beta chains and stabilizing the constrained deoxy tetramer against dissociation into alphabeta dimers. With hemoglobin specifically modified (des-Arg-141alpha) to eliminate half the constraining salt links within the dimer-dimer contact region, the dissociation rate is increased by approximately three orders of magnitude. In hemoglobin S where the amino acid substitution is not directly in the intersubunit contact region of interest, the dissociation rate is found to be approximately the same as that for hemoglobin A. Combination of the dissociation rate constants determined by haptoglobin binding with stopped-flow determinations of the rate constant for reassociation of dissociated dimers provides an estimate of the equilibrium constant, 0K2, for the deoxyhemoglobin dimer-tetramer equilibrium. This estimate is independent of any assumptions regarding other energetic quantities, and yields a value of 2.54 +/- 0.7 X 10(10)M-1 (heme) in 0.1 M Tris-HCl, 0.1 M NaCl, and 1 mM EDTA, pH 7.4, 21.5 degrees C. Thus the intersubunit contact energy is -14.0 +/- 0.2 kcal/mol of heme. The stabilization energy between deoxy and oxy tetramers is found to be approximately 6.4 kcal/mol, under these conditions.

The linkage between oxygenation and subunit dissociation in human hemoglobin. Consequences for the analysis of oxygenation curves

For human hemoglobin, a pronounced dependence of oxygenation curves upon protein concentration can be demonstrated experimentally in the range between 10(-4) and 2 X 10(-6) M heme. The effects of such protein concentration dependence upon analysis of saturation curves have been explored using a model-independent linkage analysis which incorporates the dissociation of tetramers to dimers. We have carried out stimulations of oxygenation curves representing a variety of energy distributions designed to cover a wide range of values which are relevant to known hemoglobin systems and experimental conditions. The resulting simulated oxygenation curves were analyzed by least-squares minimization procedures in terms of the tetramer binding isotherm to yield the four apparent Adair constants. These derived constants were compared with the originally assumed values used in the simulation in order to assess the extent to which their values may be altered by the presence of dimer. For each energy distribution the analysis has been carried out over a wide range of protein concentration. We have found that the presence of even small amounts of dimer that are necessarily present at the low protein concentrations commonly employed may have a devastating effect upon the reliability of Adair constant determinations. In addition to these simulated cases, we have analyzed two sets of highly precise experimental data from the literature in order to assess the degree to which constants obtained may have been influenced by the presence of dimer.

A reassessment of the echocardiogram in mitral stenosis

Echocardiographic and cardiac catheterization findings were compared in 61 patients with mitral stenosis without other significant lesions in an attempt to determine the clinical usefulness of echocardiography in the assessment of such patients. There was a poor correlation between the E-F slope on the echocardiogram and the calculated mitral valve area (r = 0.51). A review of reported data relating the E-F slope to mitral valve area indicated that echocardiographic assessment of mitral valve area had low sensitivity and specificity. The amplitude of excursion of the anterior leaflet did not differ significantly in patients undergoing valvotomy and those undergoind valve replacement. The data obtained suggest that while the echocardiogram is a reliable method of diagnosing mitral stenosis, the E-F slope is an unreliable index of the severity of the lesion.

Diastolic vibration of the interventricular septum in aortic insufficiency

The echocardiograms of 46 patients with aortic insufficiency which manifested typical high frequency vibrations of the anterior mitral valve leaflet were reviewed. All patients had overt clinical evidence of aortic insufficiency which was confirmed by angiography in 17 cases. In 17 cases (eight of whom underwent catheterization and angiography), high frequency diastolic vibrations of the interventricular septum of similar frequency to those on the anterior mitral leaflet were observed. This finding was not seen in 100 control echocardiograms from patients without clinical evidence of aortic insufficiency, and represents a previously undescribed echocardiographic manifestation of this lesion.

Antimicrobial therapy of experimental endocarditis caused by Staphylococcus aureus

The rate at which various antimicrobial agents eradicated Staphylococcus aureus from cardiac vegetations in a rabbit model of endocarditis was studied. The rate at which various drugs and combinations killed high titers of bacteria in broth correlated with the relative effectiveness of the agents in vivo. Gentamicin plus penicillin proved to be synergistic in vitro and more effective in eradicating bacteria from cardiac vegetations in vivo than was penicillin alone. Vancomycin killed bacteria at a rate similar to that for the combination of penicillin and gentamicin, and the rate for cefazolin was similar to that for penicillin alone. Clindamycin was less effective in vivo and in vitro than penicillin. Therapy with rifampin led to the emergence of resistant organisms, and, when penicillin, this drug was less effective in vitro and in vivo than was penicillin alone. This model appears to offer an effective method for evaluation of antimicrobial treatment of staphylococcal endocarditis.

Effect of a potent interferon inducer on acute and chronic lactic dehydrogenase virus viremia

The effect of a single and multiple doses of polyinosinic-polycytidylic acid (poly (I). poly(C) on lactic dehydrogenase virus viremia has been studied. A single injection of 200 mug of poly (I)-poly(C) given 6 h before infection with lactic dehydrogenase virus caused a temporary decrease in viremia of about 2.5 log10. Repeated injections of 100 mug of poly(I)-poly(C) every 24 h beginning at -24 h caused a temporary decrease in viremia of about 4.0 log 10. Therapeutic treatment with optimal dosage schedules (100 mug every 24 h) caused a reduction in viremia of 1.0 to 2.0 log10. This decrease lasted for at least 24 h after the treatment was stopped. Some possible reasons for the limited effectiveness of poly (I)-poly(C) in this system are discussed.

Role of interferon in murine lactic dehydrogenase virus infection, in vivo and in vitro

The induction of interferon (IF) by lactic dehydrogenase virus (LDV) and the action of exogenous IF on LDV multiplication have been studied in vivo and in vitro. In vivo the induction of serum IF by LDV was shown to correspond with the virus challenge dose. In vitro LDV-infected macrophages did not produce detectable IF. As to the action of IF in vivo, the prophylactic or therapeutic administration of IF to mice reduced the LDV serum titers only temporarily. In vitro, (i) the sensitivity of LDV to IF in macrophage culture was 30 times less than that of vesicular stomatitis virus, and 5 times less than that of Sendai virus, and (ii) prolonged exposure of LDV-infected macrophages to high IF concentrations did not cure the chronic infection, but only decreased the virus titer. The probable role of IF in the establishment of the early phase of a persistent but reduced viremia in mice is discussed.

Echocardiographic determination of mitral disc valve excursion

Disc excursion and opening and closing velocities of prosthetic disc valves can be measured accurately by diagnostic echocardiography. The ultrasound beam is projected along the longitudinal axis of the valve and the echoes arising from the struts, disc, and suture ring are displayed on the oscilloscope. Twenty-four patients with normally functioning mitral Beall valves of various sizes and three patients with prosthetic valve dysfunction (one Beall, two Kay-Shiley) were studied. Table 1 lists the disc excursions with standard deviations of Beall valves measured by ultrasound.

The 0.06-0.09 cm difference in excursion between models no. 103 and no. 104 valves was detected by ultrasound without prior knowledge of change in design of the valve and demonstrates the extreme accuracy of this technic. The opening and closing disc velocity averaged 22 cm/sec and 40 cm/sec, respectively.

Decrease in expected disc excursion and abnormal motion patterns were found in three patients with prosthetic dysfunction secondary to thrombus formation, and verified at operation. With continuous changes in valve designs it is important to obtain a baseline excursion and motion pattern for each patient immediately postoperatively.

Echocardiography is a useful, noninvasive, reproducible technic for accurate assessment of prosthetic mitral disc valve movement.