The purpose of this study was to determine whether or not a newer test of platelet function, Sonoclot coagulation analysis, can identify the patients who develop significant prolongation of bleeding time after aspirin ingestion. Template bleeding time, platelet aggregation in response to arachidonic acid, collagen, epinephrine, adenosine diphosphate, and ristocetin, and Sonoclot coagulation analysis were performed before and after ingestion of aspirin in 22 adult volunteers. Mean bleeding time increased from 5.32 +/- 2.16 min to 7.34 +/- 2.1 min, but remained within normal range (2.5 to 9 min). There was marked intersubject variability in the effect of aspirin on bleeding time, and difference between men and women was not significant. There was significant decrease in platelet aggregation in response to arachidonic acid, collagen and epinephrine. Sonoclot coagulation analysis did not show significant effect of aspirin administration. There was no correlation among changes in bleeding time, platelet aggregation, and Sonoclot coagulation analysis. Five patients with known platelet function disorders and prolonged bleeding times (mean = 18.5 min, range 14 to 22) without any other coagulation abnormalities were also studied. In four of these patients who had normal platelet count, Sonoclot graphs were morphologically similar to those in the volunteers with normal bleeding times, but in one patient with thrombocytopenia, morphology was altered. It is our conclusion that Sonoclot coagulation analysis is unlikely to identify patients with prolonged bleeding time in whom platelet count and other coagulation factors are normal.

Ca2+ and Mg2+ contents were measured and compared among three different malignant hyperthermia susceptible (MHS) diagnostic groups. No difference was found among mean values for Ca2+ content, whereas Mg2+ content was greater in MHS muscle. Variance of measured values was unequal and greatest among MHS muscles, suggesting a possible abnormal distribution associated with MHS. Although more muscle fibres with Ca2+ less than or equal to 12 mumol g-1 were observed in MHS muscle, this difference was not statistically significant. In contrast, non-parametric analysis showed that the population of Mg2+ values was significantly greater in the MHS muscle. This study suggests that the distribution of Ca2+ and Mg2+ values is different in MHS muscle as a result of unknown genetic factors associated with the disease.

We estimated analytical errors of the Calbiochem, Kallestad, Hyland, Meloy, Helena, and Beckman immunochemical methods for serum transferrin. Intermethod biases were determined by analysis of the "Reference Preparation for Serum Proteins" of the College of American Pathologists and by analysis of 106 patients' serum samples. We judged the acceptability of errors by comparing confidence limits for total errors with 1/4 of the normal reference intervals. The transferrin status of each patient's sample was interpreted by comparing the result of each method with the normal reference interval claimed by the corresponding manufacturer. We found that the combined effects of medically unacceptable analytical errors and inappropriate normal intervals caused results of the tested methods not to be interchangeable. The Calbiochem method identified 61 serum samples (57%) as having abnormally high transferrin concentrations. In contrast, for the same specimen, with the Meloy method we found abnormally high transferrin concentrations for only two samples (1.8%).

Abstract Four commercial products for urine glucose determination were evaluated and compared with a quantitative hexokinase procedure. We examined precision, sensitivity, and analytical recovery of glucose from glucose-supplemented urine samples and comparison of methods, using patients' samples. Only "Chemstrip uG" (Bio-Dynamics Inc.) could differentiate between 0.3 g/L (upper limit of normal) and 0.6 g/L urine glucose concentrations. "Tes-Tape" (Lilly) and "Diastix" (Ames) gave positive readings at 0.3 g/L; "Clinitest" (Ames) detected glucose only over 1 g/L. Analytical recovery of glucose was best, for all four products, between 1 and 2.5 g/L; Chemstrip uG was the most nearly accurate among the four. Between 5 and 20 g/L glucose concentrations, Tes-Tape, Diastix, and Clinitest tended to give falsely low results; the use of Chemstrip uG resulted in overestimates of concentration at 20 g of glucose per liter. Only Chemistrip uG and Clinitest (two-drop method) had linear ranges extending to 50 g/L; Chemstrip uG had better precision and accuracy at this concentration. Of the four products, Chemstrip uG had the lowest within-technologist and technologist-to-technologist random analytical errors. In method comparison on patients' samples, Chemstrip uG was significantly stronger in its association with the quantitative hexokinase method than was Diastix, Clinitest, or Tes-Tape.

Four commercial products for urine glucose determination were evaluated and compared with a quantitative hexokinase procedure. We examined precision, sensitivity, and analytical recovery of glucose from glucose-supplemented urine samples and comparison of methods, using patients' samples. Only "Chemstrip uG" (Bio-Dynamics Inc.) could differentiate between 0.3 g/L (upper limit of normal) and 0.6 g/L urine glucose concentrations. "Tes-Tape" (Lilly) and "Diastix" (Ames) gave positive readings at 0.3 g/L; "Clinitest" (Ames) detected glucose only over 1 g/L. Analytical recovery of glucose was best, for all four products, between 1 and 2.5 g/L; Chemstrip uG was the most nearly accurate among the four. Between 5 and 20 g/L glucose concentrations, Tes-Tape, Diastix, and Clinitest tended to give falsely low results; the use of Chemstrip uG resulted in overestimates of concentration at 20 g of glucose per liter. Only Chemistrip uG and Clinitest (two-drop method) had linear ranges extending to 50 g/L; Chemstrip uG had better precision and accuracy at this concentration. Of the four products, Chemstrip uG had the lowest within-technologist and technologist-to-technologist random analytical errors. In method comparison on patients' samples, Chemstrip uG was significantly stronger in its association with the quantitative hexokinase method than was Diastix, Clinitest, or Tes-Tape.

Uroflow parameter nomograms determined by nonparametric tolerance limits were established from measurements in 1,014 children. Percentile nomograms for maximum and average flow rates were based on body surface area, volume voided and sex.

A Monte Carlo simulation study to compare the effect of population form on three methods of nomogram construction was performed by taking 2000 random samples of size 5, 20, 50, 100, and 200 from populations with known percentiles. The 10th percentile was estimated by each of the three construction procedures. The three procedures compared were the upper 95 per cent nonparametric tolerance limit technique, the usual percentile approach, and a method which assumes a Gaussian (normal) distribution. Tenth percentile nomograms, classified by volume voided, were calculated by each of the three procedures for maximum flow rate determinations from 356 normal males of ages 1 to 12 years with body surface areas less than 1.1 m2. Nomograms of the three methods are validated with evaluations from two other groups of male children consisting of known abnormals with radiologically proven urethral obstructions and known normals who had repeated at home uroflow rates. The nonparametric tolerance limit approach gives conservative estimates and is superior in all cases from the standpoint of reducing false-negative results.

We followed the "abbreviated precision protocol" of the National Committee for Clinical Laboratory Standards for the evaluation of precision, accuracy, and carryover in analyses for glucose with the "Ektachem." We analyzed 760 clinical samples by this technique, by the FDA Proposed Class Standard glucose reference method, and with the Beckman System I GLU/BUN Analyzer. Precision and accuracy were estimated for 500, 1000, 1200, 1500, and 3000 mg/L glucose concentrations in 100, 30, or 20 microL of serum or plasma. Potential interference of 19 compounds was evaluated. Random error (1.965 X SD) was 22, 30, 34, 40, and 88 mg/L. Systematic error was 8, 1.5, -2, -5, and -27 mg/L. Total analytical error was 30, 32, 36, 46, and 110 mg/L for analysis of 100 microL of serum at the above-stated glucose concentrations. The greatest interference (-39 mg/L) in the glucose (at 1200 mg/L) determination was caused by L-ascorbate (40 mg/L). Glucose concentrations as determined with the Ektachem were found to be linearly related to the expected concentration up to at least 5660 mg/L. Carryover was not statistically significant.

Received from the Departments of Anesthesiology and Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston, Texas 77550. Accepted for publication July 19, 1979. Reported in part at the annual meeting of The American Society of Anesthesiologists, New Orleans, Louisiana, October 1977.

Patients vary widely in their patterns of recovery from surgery. To better understand this variation a double blind study of 34 patients (21 men, 13 women) who were hospitalized in an 800-bed hospital for elective orthopedic surgery was conducted. Patients found to be higher in hospital anxiety tended to have more medical complications and consequently longer hospitalizations, whereas patients found to be lower in hospital anxiety tended to have fewer medical complications and consequently shorter hospitalizations. Also, this study demonstrates that the personality dimension of internal-external locus of control is significantly related to hospital anxiety. These results are interpreted as a hypothesis about the role of information and coping style in surgical recovery: internals attempt to influence the course of their recovery by acting on their environment by using information as a cue to appropriate behavior while externals incapacitated by anxiety may fail to recognize ways in which they can cope with the threat of the surgical experience. Appropriate statistical and methodological procedures for this type of study are discussed.

Water urethral closure pressure profiles were evaluated in 66 women for reproducibility between sequential studies in patients and 3 observers.

Carbon dioxide urethral pressure profiles were analyzed under the same conditions for 113 spina bifida and 87 non-spina bifida patients categorized by sex and age. Either duplicate or triplicate measurements were obtained from each patient for parameters of continence length, closure pressure and functional length. The degree of reproducibility of each parameter varied depending on age, sex and diagnosis. Except for 1 age-sex category closure pressure exhibited the smallest degree of relative variation for spina bifida patients. Results for non-spina bifida patients were mixed in that the measurement of no one parameter resulted in a uniformly smallest degree of relative variation. Reproducibility based on within patient variability generally was least for the continence length.

Dantrolene, a skeletal muscle relaxant, has been proven prophylactic and therapeutic for malignant hyperthermia (MH) in swine. This study examined the feasibility of using a dantrolene dose response as measured by indirectly evoked foretoe twitch depression as a means to safely discriminate MH susceptibility in swine. The effect of halothane on the dantrolene response was quantified. Subjects were five Poland China malignant hyperthermia susceptible (MHS) and five Hampshire malignant hyperthermia resistant (MHR) swine. Dantrolene dose response was determined twice in each anaesthetized subject, once with thiopentone and subsequently with thiopentone and halothane. Dantrolene in incremental doses, 0.15 mg.kg-1, was given to a cumulative dose of 2--3 mg.kg-1. Under thiopentone anaesthesia, the dantrolene dose responses were similar in MHS and MHR animals. The presence of halothane augmented dantrolene twitch depression in MHS but not MHR animals when compared to their response under thiopentone. Under halothane, the MHS animals had significantly augmented dantrolene response compared to MHR pigs, but three MHS animals had developed the MH syndrome prior to receiving dantrolene. We conclude that dantrolene muscle relaxant dose response cannot be used as a diagnostic test for MHS in swine. Halothane augments dantrolene twitch depression in MHS swine.

Five methods of assessing blood in urine were studied and compared: sedimentation count, hemacytometry, "Clini-lab" reagent strip and "N-Multistix" and "ChemStrip-8" dipsticks. The minimum sensitivity of two commercially available urine dip-stick procedures for blood was established. The study includes method association, assay variation among and within technologists, accuracy, precision, and sensitivity. Our results demonstrate generally poor association between results by the dip-stick procedures and the hemacytometer or sedimentation count. Results by the last two procedures also showed very poor association with each other.

To the Editor.— Obesity is a major health problem. Considerable effort and funds are expended by the medical and lay public on weight-reduction programs. Morbidly obese persons are predisposed to cardiovascular and pulmonary disease and have an increased mortality compared with the nonobese. These obese persons also have an increased anesthetic and surgical risk (175:657, 1961).1-4Yet, the medical community has not adopted a commonly used method of quantifying obesity. Seltzer5has pointed out that consideration of only height and weight does not necessarily indicate fatness, and he introduced the ponderal index (PI) as a better indication of body build. The index is defined as follows: For a given PI value, weight as a measure of volume increases according to the cube of the linear dimensions (235:2476, 1976). The lower the PI, the more obese the individual. Using the PI, Seltzer5showed that the ratio of actual

The effects of varying temperatures from 25 degrees to 37 degrees C on calcium binding characteristics of sarcoplasmic reticulum from malignant hyperthermia-susceptible (MHS) and control pig muscle were examined. Two groups of MHS pigs were included: those with high susceptibility to malignant hyperthermia (MHS group) and a cross-bred, less susceptible group (MHX). At 25 degrees C, calcium binding was lower for MHS than for controls and MHX. As temperature was increased by 2 degrees C jumps, calcium binding decreased in all sarcoplasmic reticulum fractions. At 35 degrees C a sharp decrease in calcium binding occurred in the MHS and MHX fractions. The sharp decrease in calcium binding at 35 degrees C differentiated the MHS and MHX fractions from controls. The initial velocity (Vi) for calcium binding was lower in MHS fractions between 25 degrees and 35 degrees C when compared with MHX and controls. All fractions had increased Vi values as temperature increased from 25 degrees to 35 degrees C. From 35 degrees to 39 degrees Vi for controls increased markedly. In contrast, Vi for the MHX fraction decreased as temperature exceeded 35 degrees C. These temperature effects on calcium binding characteristics of sarcoplasmic reticulum from MHS and MHX muscle may be indicative of a membrane transition that impairs calcium binding.

The hyperglycemic activities of epinephrine (EPI) and isoproterenol (ISO) in baboons correlated with their ability to increase plasma glucagon (IRG) levels relative to insulin (IRI). EPI inhibited IRI release and produced greater increases in plasma glucose and IRG than did ISO. ISO increased plasma IRI levels more than IRG. Infusion of somatostatin blocked IRG release and inhibited hyperglycemic responses to EPI by approximately 50%. These findings indicate that, as in man, IRG release contributes significantly to the hyperglycemic effects of catecholamines in baboons. The baboon thus appears to be a suitable model for predicting effects of drugs on glucose homeostasis in humans.

The accuracy and precision of urinary pH determinations using commercially available dipsticks were studied. Two products were evaluated by 17 MT(ASCP) technologists over the pH range 4.5 to 9.0. The study included accuracy, reproducibility, variation among technologists, and variation between products. The results demonstrated considerable variation among technologists, products, and true pH levels in dipstick urinary pH determinations, and that very good or very poor results could be obtained, depending on the true pH level being sampled and on the choice of technologist.

Two urine dip-stick assays for glucose were studied and compared to a quantitative hexokinase procedure. We determined sensitivity, specificity, predictive value of "normal" and "abnormal" dip stick results, assay efficiency, technologist precision, and method association. Precision was poor. Attempts to estimate urine glucose concentration with the dip sticks frequently produced gross inaccuracies. We believe the dip stick glucose assay should be considered qualitative only; as a qualitative test, the dip sticks are fairly efficient at distinguishing glucose concentrations of less than 0.3 g/L from concentrations greater than 0.3 g/L.