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Biomedical subjects

D Rodbard

Publications and source records attributed to D Rodbard.

At least 145 records · Page 8Linked to original sources
PubMed1976

Improved diagnosis and management of hyper- and hypothyroidism by timing the arterial sounds.

"Sphygmo-Recording," a non-invasive method for timing the arterial pulse wave contour provides an objective measure of responses to medication in patients with hyper- and hypothyroidism. The QKd interval, i.e., the interval from the onset of the QRS complex (Q) to the onset of the Korotkoff sounds (K) at the brachial artery when the sphygmomanometer cuff is at diastolic pressure (d) is the QKd interval. QKd is normally 205 +/- 12 msec. In the hyperthyroidism the QKd interval may be shortened to 110 msec. In hypothyroidism the QKd interval may be prolonged to 320 msec. Changes in QKd parallel changes in clinical status and serum total T4 and T3, measured by radioimmunoassay. QKd can be used as an objective guide to antithyroid therapy in hyperthyroidism and replacement therapy with thyroid hormone in hypothyroid individuals.

Adult↗
PubMed1976

Statistical characterization of the random errors in the radioimmunoassay dose--response variable.

We have developed practical methods for evaluating the magnitude of the random errors in radioimmunoassay dose--response variables, and the relationship between this error and position on the dose--response curve. This is important: to obtain appropriate weights for each point on the dose--response curve when utilizing least-squares curve-fitting methods; to evaluate whether the standards and the unknowns are subject to error of the same magnitude; for quality-control purposes; and to study the sources of errors in radioimmunoassay. Both standards and unknowns in radioimmunoassays for cAMP and cGMP were analyzed in triplicate. The same mean (Y), sample standard deviation, sy, and variance (2-y) of the response variable were calculated for each dose level. The relationship between s 2-y and y was calculated utilizing several models. Results for standards and unknowns from several assays were pooled, and a curve smoothing procedure was used to minimize random sampling errors. This pooling increased the reliability of the analysis, and confirmed the presence of the theoretically predicted nonuniformity of variance. Thus, the calculation of results from these radioimmunoassays should utilize a weighted least-squares curve-fitting program. These analyses have been computerized, and can be used as a "pre-processor" for programs for routine analysis of results of radioimmunoassay.

Analysis of Variance↗
PubMed1976

Noninvasive monitoring of adriamycin cardiotoxicity by "Sphygmo-Recording" of the pulse wave delay (QKd interval).

Eighty patients with Ewing's sarcoma, bronchogenic carcinoma, and other neoplasms receiving adriamycin were monitored by a Sphygmo-Recording of the pulse wave delay (QKd time interval). The QKd interval, which is the sum of the cardiac pre-ejection period and the pulse transmission time, is sensitive to changes in myocardial contractility and stroke output. The patients were also followed by serial physical examinations, electrocardiograms, chest roentgenograms, serum enzymes, and thyroid function tests; none of these changed during the study period except in a few patients with congestive heart failure (CHF) and/or transient arrhythmias. QKd showed a significant prolongation (greater than 30 msec) within 1-3 weeks after adriamycin administration in a high percentage of patients followed closely. The QKd interval usually returned to pretreatment baseline levels within 4-7 weeks after adriamycin administration. The QKd often showed repeated and sustained elevations after courses of therapy at 3-week intervals. After adriamycin therapy was discontinued the QKd usually returned to normal levels. No statistically significant changes in the QKd were seen in a control group. There were no acute changes in QKd during adriamycin infusions. Of seven patients receiving cumulative doses of adriamycin greater than 550 mg/m2, three developed CHF. QKd intervals in all three of these patients had failed to return to the baseline values 2-3 months prior to any other evidence of CHF. This suggests that failure of QKd to return to pretreatment baseline levels may be of prognostic value. The QKd interval appears to reflect a high incidence of subclinical adriamycin cardiotoxicity. The technique is simple, noninvasive, rapid, and potentially useful for monitoring patients receiving adriamycin and other potentially cardiotoxic drugs.

Adult↗
PubMed1975

Charge properties of human pituitary and amniotic fluid prolactins.

The apparent isoelectric points (pI) in isoelectric focusing (IF) of human pituitary and amniotic fluid prolactin (hPRL), both non-iodinated and iodinated, were determined. Unresolved mixtures of pituitary hPRL isohormones E and F, and of at least five isohormones found in amniotic fluid, and plasma hPRL exhibit an average pI value of 6.5 - 6.7. Transient state pH values observed or previously reported for hPRL components range from pH 5.9 to 6.8 after correction to standard conditions. At pH 8.1, the major isohormone, hPRL-F, carriers a charge of 2.2 net protons per molecule. The net charge differences among isohormones E, F and G are compatible with acquisition or loss of single charged groups per 20,000 molecular weight. This net charge is similar to that of the least prolactin-bioactive major isohormone of human growth hormone (hGH-B), while the hGH with a bioactivity comparable to that of hPRL exhibits a net charge of 3.4 valence units. The "large" isohormones J and H increased net charges, by a factor of 2-3, in direct proportion to their size increments.

Amniotic Fluid↗
PubMed1974

Apparent positive cooperativity in the mechanism of action of luteinizng hormone.

In vitro accumulation of cyclic AMP by rat Leydig cell preparation and mouse tumor Leydig cells in response to exogenous LH appears to display an apparent Hill coefficient of 2.5. This is suggestive of positive cooperativity at a level intermediate between binding and cyclic AMP production, although several alternative hypothesis cannot be excluded on the basis of these data alone. The Hill coefficient for testosterone is higher than unity, although it has not been established with adequate precision in these experiments.

Animals↗