David C. Hurst

Ictal EEG wave forms from epidural electrodes predictive of seizure control after temporal lobectomy

Ictal wave form characteristics--frequency, spatial distribution, and duration--were analyzed for 140 complex partial seizures recorded from epidural strip electrodes implanted in 28 patients. None had abnormalities on imaging studies. All had bilateral electrode placements, unilateral seizure onsets, temporal lobectomies, and were followed for a mean of 33 months postoperatively. Sixteen patients (57%) became free of complex partial seizures: 12 had reductions in seizure frequency of at least 50% but were not seizure-free. The only predictor of the seizure-free state was the presence of low voltage fast activity (LVF), in the alpha or beta ranges, localized to one gyrus. This phenomenon occurred in 14/16 seizure-free patients, 2/12 of others (P < 0.001). As seizures progressed, LVF typically increased in amplitude, propagated, and slowed into the theta range. Wave forms were classified into 8 categories based upon their frequency and morphology. Stepwise discriminant analysis of these wave forms, with consideration of whether they were localized or regional, revealed that both frequency and localization were critical for the post-surgical prognosis. The mere presence of a localized seizure onset was unreliable unless the wave form was taken into account. Well-localized rhythmic activity over 8 Hz at seizure onset from epidural subtemporal electrodes predicts surgical success. Slower rhythms imply greater separation in space and time from seizure onset.

Comparison of the Vectorcardiogram with the Electrocardiogram in the Prediction of Left Ventricular Size

The vectorcardiogram has been suggested as an alternative to the electrocardiogram in the diagnosis of left ventricular enlargement. In 107 patients, precordial QRS voltage measurements were compared with vectorcardiographic spatial magnitude measurements in their relationship to angiocardiographically determined left ventricular mass and volume.Sensitivity, specificity, and linear correlations obtained with instantaneous spatial QRS magnitude measurements were similar to those obtained with selected precordial voltage measurements suggested by Sokolow and Grant. Multiple regression analysis incorporating time-strength integrals of the spatial QRS correlated more closely with left ventricular mass (R = 0.75) and total volume (R = 0.80) than did similar analysis using precordial voltages (R = 0.71). These differences are statistically significant (P = <0.01) but reduce the remaining variability of the electromotive-left ventricular size relationship by only 7 to 14% and leave 30 to 40% of the total variability unexplained. These findings do not support a large practical advantage for the vector-cardiogram over the electrocardiogram in the prediction of left ventricular size.

Submaximal Exercise Testing in a Random Sample of an Elderly Population

To examine the electrocardiographic response to exercise in an older population, 280 participants in a longitudinal study of cerebrovascular disease were tested. Subjects were randomly selected from the total 50 to 69-year-old population of Birmingham, Alabama. Approximately 60% of the participants reached a heart rate more than 80% of their predicted maximal heart rate.Subjects were divided into three groups on clinical grounds: (I) vascular disease, (II) risk factor(s) only, and (III) normal. Positive tests (at least 0.10 mv of ischemic ST-segment depression) were most frequent in group I (24%), though not significantly different from group II (19%) and group III (12%).Hypercholesterolemia was significantly associated with a positive exercise test only in those subjects with vascular disease. Nonspecific ST-T wave changes on the resting electrocardiogram were associated with a positive test in all subjects, but with only a borderline test in those subjects without vascular disease. No significant associations were noted between abnormal exercise test and either cigarette smoking or hypertension.

A study of the single radial hemolysis in gel system—I factors affecting the model

Abstract Mouse hemolytic 19S antibodies can be quantitatively measured if they are allowed to radially diffuse in an agar plate containing the erythrocyte antigen. After diffusion and subsequent lysis with complement a linear relationship can be seen between the area of lysis and the square root of the antibody dilution. It is found that the temperature does not affect the area of lysis obtained; however, the erythrocyte concentration, agar concentration and time do affect the slope of the line for any antibody preparation. When care is taken, only 4·37 per cent error was observed.

A study of the single radial hemolysis in gel system—II application of the model to mouse 19S hemolytic antibodies

Abstract A quantitative method for the determination of mouse anti-SRBC has been described in the previous paper (Hiramoto et al., 1971). The mathematical formulation used to derive the slope was least square; theoretical and practical uses of these comparisons are given below. In addition, reconstruction experiments were performed to further test this system. In the first experiment, an antiserum was partially diluted and then compared with a different antiserum standard. In the second experiment, the same antiserum was diluted by one-third and compared with the original.

A simple method for quantitation of hemolytic antibodies

Abstract A simple and reproducible method for the quantitation of hemolytic SRBC serum is presented. The method involves the use of agar-SRBC plates, and antibody is allowed to diffuse radially. After a sufficient amount of time, the plates can be developed by the direct addition of complement. After zones of lysis were complete, the area of lysis was found to be directly proportional to the square root of the serum dilution.

Methodology a study of the single radial hemolysis in gel system-III. Quantitation of complement☆

Abstract Application of the RHG method for quantification of complement (C′) is described. The measurements of potency obtained by the radial hemolysis in gel plates for different lots of C′ agree with the values obtained by conventional tube titration. With properly standardized plates, the RHG method can determine the CH 50 units of different lots of C′ using an experimentally determined area of lysis ( y ) value obtained for CH 50 /ml. This also allows the estimation of residual CH 50 /ml after complement fixation by antigen-antibody.

INTESTINAL COMPLICATIONS IN RHEUMATOID ARTERITIS AND THEIR RELATIONSHIP TO CORTICOSTEROID THERAPY

Abstract 1488 selected case reports of patients with rheumatoid arthritis were reviewed for intestinal arteritis as a complication of rheumatoid arteritis and for any possible relationship of this complication to previous steroid therapy. A total of 254 patients was found with rheumatoid arteritis, of whom 144 had received preceding steroids. Intestinal arteritis was described in 43 patients. These patients were divided into steroid and non-steroid treated groups: 31 had received previous steroid therapy, 9 had not, and in 3 steroid therapy was not described. There was no difference between the two groups in age of onset, duration, or staging of arthritis. Further comparison between the steroid and non-steroid treated groups disclosed no significant difference in occurrence of intestinal complications, histology of the lesions, or number of lesions per patient as a cause of death. From these observations it appears that steroid therapy neither causes nor aggravates arteritis in rheumatoid disease.