Demonstration of a relation between urinary digoxin-like immunoreactive substance and cardiac performance.

OBJECTIVE: To determine the relation between urinary digoxin-like immunoreactive substance (DLIS) and cardiac performance. DESIGN: Cohort study. SETTING: Echocardiography laboratory of a university-affiliated teaching hospital. SUBJECTS: Thirty-four individuals referred for echocardiographic studies who had never received cardiac glycosides or other substances known to cross-react with a digoxin radioimmunoassay and had no condition that has been associated with increased DLIS. MEASUREMENTS: Cardiac dimensions and indices of cardiac performance derived from echocardiograms and cardiac Doppler flow studies and concentrations of urinary DLIS, creatinine, and electrolytes. RESULTS: Urinary DLIS ranged from < 0.125 ng (digoxin equivalents) per milliliter (below the sensitivity of the assay) to 0.99 ng/ml, averaging 0.22 +/- 0.24 ng/ml. On bivariate analyses, UDLIS was found to correlate significantly with body weight, left ventricular (LV) end-diastolic dimension, LV fractional shortening, mitral transvalvular flow velocity following atrial systole, and urinary calcium. On multivariate analyses, the association between urinary DLIS (alone or adjusted for urinary creatinine) and LV fractional shortening emerged as the paramount independent relation. CONCLUSION: Urinary DLIS can be related to cardiac performance under steady-state conditions. This suggests that DLIS may be a ligand for a cardiac glycoside receptor.

Perilymphatic fistulas in children: rationale for therapy.

We report 26 consecutive patients (32 ears) who were identified in a 2 year period (July 1, 1985-June 30, 1987) with unexplained sudden, fluctuating, or progressive sensorineural hearing loss (SNHL). All patients underwent an exploratory tympanotomy and a perilymphatic fistula was identified in 13 patients (14 ears). The mean change of 14 +/- 27 dB in speech reception threshold before and after surgery was significant at p = 0.08 among children with fistula and ranged from -30 to 80 dB. In children with sudden, progressive or fluctuating SNHL and multiple sensory deficits, including blindness or contralateral SNHL, or prior head trauma, prompt surgical exploration is mandatory. Additionally, the aggressive management of otitis media with effusion is essential in such patients to minimize fluctuations in hearing caused by superimposed conductive hearing loss. Caution must be exercised to separate fluctuating hearing loss from fluctuations in audiologic testing.

Urinary digoxin-like immunoreactive substance in pregnancy. Relation to urinary electrolytes.

High concentrations of digoxin-like immunoreactive substance (DLIS) have been identified in amniotic fluid and in blood during pregnancy. In this study, urine from healthy women was analyzed for DLIS during pregnancy and following delivery, and levels were related to various clinical and urinary findings. Urinary DLIS increased progressively during pregnancy, having a linear relation to gestational week (DLIS = 0.032 week + 0.46, Syx = 0.52, r = 0.46, p less than 0.01), and fell to nonpregnant values during the first postpartum day. The urinary DLIS level correlated with urinary creatinine (r = 0.50, p less than 0.01) and urinary calcium (r = 0.56, p less than 0.01) levels. When adjusted for the gestational week, the urinary DLIS level also correlated with urinary potassium (r = 0.48, p less than 0.01), creatinine (r = 0.55, p less than 0.01), and magnesium (r = 0.55, p less than 0.01) levels. After adjustment for the urinary creatinine level, only the relation of urinary DLIS and urinary calcium levels remained significant (r = 0.44, p less than 0.05). The urinary DLIS level was not found to be related to systemic blood pressure. The ratios of sodium to potassium (r = -0.43, p less than 0.05) and calcium to magnesium (r = 0.37, p less than 0.05) were also related to gestational week but were independent of the urinary DLIS level. Thus, urinary DLIS increases progressively during pregnancy and falls to nonpregnant values on the first postpartum day, the urinary DLIS level can be related to urinary creatinine, urinary potassium, and urinary magnesium levels, and when adjusted for the urinary creatinine level, the urinary calcium level relates independently to the urinary DLIS level.

Filtered word testing in the assessment of children's central auditory abilities.

The purpose of this study was to evaluate the effects of various cut-off frequencies on low-pass filtered speech discrimination test results obtained from children. Two groups of children, one presumed to have normal auditory perception and the other with auditory learning disabilities, were tested. Phonetically Balanced Kindergarten word list words were low-pass filtered at 1000 Hz, 750 Hz, and 500 Hz. The results indicate a clear separation of groups for the 1000 Hz filtered condition only. The implications of these preliminary test findings are discussed.