Biomedical subjects

R Giebel

Publications and source records attributed to R Giebel.

3 recordsLinked to original sources

PubMed1993

Endogenous natriuretic factors 1: sodium pump inhibition does not correlate with natriuretic or pressor activities from uremic urine.

It is our purpose to isolate and characterize the putative "Natriuretic Hormone", ostensibly responsible for ECF homeostasis, as well as identify endogenous pressors and compounds that induce prolonged natriuresis; we report here our initial progress in this area. Large volumes of pooled urine collected from uremic patients were fractionated, and the resulting isolates were evaluated for in vivo natriuretic and pressor effects and Na+/K(+)-ATPase inhibitory activity in renal cells. The purification steps involved ultrafiltration to obtain materials of less than 3000 da, gel filtration, and sequential reversed-phase high performance liquid chromatography (HPLC). After each HPLC step, the fractions were evaluated for their ability to elicit significant natriuresis and/or influence mean arterial pressure in the normal conscious female rat. Each fraction was also assayed for its ability to inhibit Na+/K(+)-ATPase as determined by the inhibition of 86Rb+ uptake into MDBK renal cells. While several of the fractions elicited profound natriuresis and/or pressor activity and other fractions inhibited Na+/K(+)-ATPase, there was no correlation among the activities in individual fractions. We have concluded that this plethora of bioactivities is responsible for much of the confusion and multiplicity of crude isolates claimed to be the putative hormone. Presently we are attempting to purify each of these activities to chemical homogeneity for structure determination.

Animals↗

PubMed1988

Septic shock during pregnancy.

A multiinstitutional review of 10 pregnancies complicated by septic shock was undertaken to identify the clinical characteristics and hemodynamic alterations associated with this condition. Prolonged rupture of membranes with the subsequent development of chorioamnionitis or postpartum endometritis were risk factors that commonly preceded the diagnosis of septic shock. The majority of septic shock cases occurred during the puerperium. There were two maternal deaths in this selected series. Associated complications included pulmonary edema, adult respiratory distress syndrome, disseminated intravascular coagulation, pulmonary emboli, and cardiac arrest. The primary hemodynamic derangements were reduced systemic vascular resistance with depressed myocardial function. The mean initial systemic vascular resistance index in eight surviving women was 885 +/- 253 dyne.sec/cm5.m2. Despite an overall presenting cardiac index of 4.20 +/- 2.01 L/min/m2, five patients (50%) had evidence of myocardial depression based on analysis of their left ventricular function curves. Mean arterial pressure, systemic vascular resistance, and left ventricular stroke work index all showed significant improvement after therapy. A hemodynamic algorithm based on volume therapy, inotropic agents, and peripheral vasoconstrictors is offered. This therapeutic approach is designed to optimize cardiac performance and maintenance of organ perfusion in the critically ill patient with septic hypotension during pregnancy.

Blood Pressure↗

PubMed1987

Indirect blood pressure monitoring in the postpartum patient.

Direct intra-arterial blood pressure (BP) measurements were compared with simultaneous standard cuff sphygmomanometry and automated inflatable cuff manometry in 12 postpartum patients. An adjustable arterial damping device was used to correct overestimations of systolic values due to distorted pressure waveforms. No significant differences in diastolic pressure with and without arterial damping were noted between noninvasive techniques and direct intra-arterial values. The systolic readings obtained with the standard cuff were significantly lower than the intra-arterial values with or without the arterial damping device (P less than .001 in both cases). However, mean systolic BP by automated cuff did not differ significantly from intra-arterial readings in the presence of the damping device (P = .10, not significant). We recommend indirect BP monitoring by automated cuff manometry in nonobese critically ill patients requiring frequent BP readings, and arterial catheter in situations requiring frequent arterial blood samples or oxygenation assessment.

Blood Pressure Determination↗