Visual acuity measurements by swept spatial frequency visual-evoked-cortical potentials (VECPs): clinical application in children with various visual disorders

Previous studies have indicated that visual acuities of normal infants can be estimated with good accuracy using swept spatial frequency visual-evoked-potentials (VECPs). In this report we describe acuity measurements obtained with this technique from 304 examinations performed on 135 children having various visual disorders. When possible, two or more different stimulation frequencies (8, 12, 15 or 24 contrast reversals/sec) were used in each patient, and three to eight sweep VECPs were obtained from each patient under each simulation and recording condition. High correlation coefficients (0.94 - 0.96) between the acuity estimated on each patient from either the single sweep giving the best visual acuity (BSS) or from vector averages (VeA) of the EEG data obtained from several sweeps confirmed previous findings in normal infants. We also found high correlation coefficients among BSS recorded at different temporal frequencies (0.79-0.97) and among comparisons of BSS or VeA acuity to optotype visual acuity (0.6-0.89). Children with clinically undetectable optokinetic responses showed lower visual acuity estimated by BSS than those who demonstrated optokinetic nystagmus. We conclude that the sweep VECP is a valid method, giving estimates of acuity which correlate well with optotype acuity and correspond well to other clinical findings, and that it can be useful in the clinical management of nonverbal patients.     

The concentration of the 35-kDa surfactant apoprotein in amniotic fluid from normal and diabetic pregnancies

A specific, enzyme-linked immunoabsorbent assay was used to determine the concentration of the 35,000 mol wt surfactant apoprotein (SP-A) in samples of amniotic fluid obtained from nondiabetic (n = 358) and diabetic (n = 29) women. The enzyme-linked immunoabsorbent assay was performed with rabbit antibodies directed against SP-A present in lavage fluid from a patient with alveolar proteinosis. Amniotic fluid SP-A concentrations increased as a function of gestational age, from less than 3 micrograms/ml at 30-31 wk to 24 micrograms/ml at 40-41 wk, and were positively correlated with the lecithin to sphingomyelin ratio (p less than 0.01). SP-A concentrations also increased as a function of gestational age in shake test positive samples (p less than 0.05), but were unchanged in shake test-negative samples. There was no difference in the surfactant apoprotein concentration of male compared with female fetuses at any gestational age. In amniotic fluid obtained from 20 diabetic women, SP-A levels were significantly less than in nondiabetic pregnancies that were matched for gestational age and sex of the fetus (p less than 0.05). The SP-A concentrations in amniotic fluids obtained from nine women who were diabetic and hypertensive and from 10 hypertensive women were not different from matched controls. The relationships described above were valid whether the SP-A concentration was expressed per mg protein or per ml amniotic fluid. These data are suggestive that the concentration of amniotic fluid SP-A is decreased in diabetic pregnancies.     

Defibrination syndrome after intra-amniotic infusion of hypertonic saline

To determine the role of changes in coagulation factors in hermorrhagic complications after intraamniotic infusion of hypertonic saline for therapeutic abortion, 21 women undergoing this operation, ranging 15-38 years in age with an average gestation of 18 weeks, were studied for coagulation factors, fibrinogen survival, and plasma volume. Blood tests were taken before, immediately after, and at 3-hour intervals after infusion of hypertonic saline. Significant changes were found in the following factors: Thrombin clotting time was consistently prolonged from the third hour after infusion. The platelet count dropped significantly from 310,000/cu. mm before infusion to 223,000/cu. mm 18 hours later. Fibrinogen levels dropped significantly from a mean preinfusion level of 393 mg/100 ml to 297 mg/100 ml at 18 hours. Factor VIII levels also fell significantly from 131% of normal at preinfusion to 85% of normal at 6 hours. Factor V levels declined significantly from a preinfusion mean of 104% of normal to 91% at 6 hours, though the rate of decrease varied widely among the patients. Fibrinogan/fibrin, degradation products, negative at preinfusion, appeared in all patients serums. Euglobulin lysis time was not accelerated. Fibrinogen survival studies were conducted in only 5 patients, 4 of whom showed a significant decrease, notably immediately preceding abortion, with a highly significant correlation to the time from infusion. Plasma volume increased significantly with a corresponding decrease in hematocrit. It is concluded that a mild form of diffuse intravascular coagulation develops after the intraamniotic infusion of hypertonic saline, but further research is necessary to pinpoint the cause of serious coagulopathy and hemorrhage.     

Erythema Chronicum Migrans in Three Soldiers

Three cases of erythema chronicum migrans in soldiers who had returned from active duty in Central Europe were seen within a ten-week period in San Francisco. Typically, the lesions cleared in less than five days with penicillin in two cases and erythromycin in another.