Lactic dehydrogenase isoenzyme determination in the diagnosis of acute myocardial infarction

Lactic dehydrogenase (LD) isoenzymes were determined by a rapid, simple technique and their utility in the diagnosis of acute myocardial infarction (AMI) was evaluated. LD isoenzymes were separated by ion-exchange column chromatography using DEAE-Sephadex. The cardiac fractions (LD-1 and LD-2) were measured separately on an Abbott ABA-100 analyzer and ratio of LD isoenzyme 1 to LD isoenzyme 2 (LD1:2) calculated. Daily serum samples were obtained from 100 patients selected only for a history of chest pain of abrupt onset. In 47 patients whose diagnosis was acute myocardial infarction (AMI), confirmed by typical clinical presentation and typical rise in cardiac-specific creatine kinase isoenzyme (MB(, peak LD1:2 ranged from 0.77 to 2.26. In 44 patients without AMI, peak LD1:2 ranged from 0.25 to 0.76. In two patients with electrocardiographic changes chest pain occurred two and five days previously; there was no rise in MB, but LD1:2 was elevated. Four patients with small AMI had no rise in LD1:2. Three more patients (one with active hemolysis) had false positive results. Thus, there was a sensitivity of 96% and a specificity of 97% when the cut-off point was LD1:2 = 0.76. LD1:2 is not quite as sensitive or specific as MD, but the ratio allows for the diagnosis of infarction in cases where MB has already returned to normal.     

Male victims of sexual assault.

OBJECTIVE--To compare the demographics, physical findings, and assault characteristics of incarcerated, sexually assaulted men with those of nonincarcerated, sexually assaulted men. DESIGN--Case series of 99 adult male victims of sexual assault evaluated over a 3-year period. SETTING--Memphis Sexual Assault Resource Center, a nonhospital-based clinic that serves as the primary resource for sexually assaulted victims in the Memphis and Shelby County, Tennessee, area. PARTICIPANTS--All adult male victims of sexual assault evaluated at the Memphis Sexual Assault Resource Center during the study period were included in the study. Ninety-nine victims were studied, including 80 incarcerated men and 19 men from the community. RESULTS--The victims of sexual assault in the community group were older than the victims in the incarcerated group. Apart from the age difference and weapon use, there were no statistically significant differences between the incarcerated and nonincarcerated victims. CONCLUSIONS--The similarities between the two groups suggest that sexual assault of men may not be unique to prisons, and all men are potential victims. Further studies are required to better understand these crimes and to develop education and prevention programs.     

Detection of myocardial ischemia in vitro by computed tomography

The applicability of CT in the delineation of ischemic myocardium is defined. Twenty-six dogs had their left anterior descending coronary artery occluded, and radiolabeled microspheres were injected into the left atrium to measure myocardial blood flow. From 30 minutes to 7 weeks after coronary occlusion the hearts were excised and scanned in a CT head scanner. An unbiased observer divided selected CT scans slices into normal, abnormal, and borderline areas of attenuation coefficients; these were correlated with blood flow measurements and a progressive decrease in flow from normal to borderline and borderline to abnormal segments was found. As early as 2 hours after coronary arterial occlusion, areas of reduced attenuation coefficient, corresponding to regions of reduced blood flow, were seen. Areas of increased attenuation were seen in regions containing microcalcifications and fibrosis in several longer term experiments. Areas of reduced blood flow were visible immediately after coronary arterial occlusion with intravenous iodinated contrast material (1 ml/kg). CT detection of regions of reduced blood flow defined by radiolabeled microsphere is a promising means of detecting and sizing myocardial infarcts.     

Effects of urethane on hippocampal unit activity in the rat

MERCER, L. F., JR., N. R. REMLEY AND D. P. GILMAN. Effect of urethane on hippocampal unit activity in the rat. BRAIN RES. BULL. 3(5)567–570, 1978.—The effect of urethane on hippocampal single unit activity in rats paralyzed with gallamine triethiodide was examined to determine possible influences of urethane as an anesthetic for electrophysiological recordings. With intravenous injections of urethane (1.0 g/kg body weight), hippocampal units responded initially with a substantial decrease in spontaneous firing rate. Activity in some cells recovered partially after a period of approximately 45 min. The activity of the remainder of cells recorded remained depressed for periods of time up to 1.5 hr. Longer periods of depression were observed in some cells. The difference in susceptibility to urethane in the population of hippocampal cells may offer a selective alteration in patterns of spontaneous activity in the hippocampus and systems efferent to the hippocampus. A knowledge of such alterations may prove important in interpreting the results of electrophysiological recording in preparations under urethane anesthesia.