LaRhee Henderson

Enalaprilat improves systemic cardiovascular parameters and mesenteric blood flow during hypotensive resuscitation from hemorrhagic shock in dogs.

Resuscitative interventions that improve mesenteric perfusion without causing instability in systemic arterial pressures may be helpful for improving trauma patient outcomes. Blocking angiotensin II formation with enalaprilat may be such an intervention. Two questions were addressed in this two-part study investigating resuscitation from hemorrhagic shock in dogs: Can systemic arterial pressures be maintained while administering a constant rate infusion of enalaprilat during resuscitation, and can enalaprilat improve cardiovascular status during resuscitation? Animals were hemorrhaged to a mean arterial pressure (MAP) of 40 to 45 mmHg for 30 min and then 30 to 35 mmHg for 30 min. Group I (n = 5) was resuscitated to a MAP 60 to 65 mmHg with enalaprilat (0.02 mg/kg/h). Group II was resuscitated to a MAP 40 to 45 mmHg with (n = 5) or without (n = 5) enalaprilat. Resuscitation in both groups consisted of intermittent intravenous lactated Ringers solution (60 mL/kg/h) to reach and maintain the target MAPs. Systemic arterial pressures were unaffected by enalaprilat during resuscitation in Group I, allowing us to proceed to the second study. During severely hypotensive resuscitation (Group II), systemic arterial pressures were also stable and enalaprilat administration was associated with increases (P ≤ 0.02) in cardiac index (+1.2 L/min/m2), stroke volume index (SVI) (+14.5 mL/m2), superior mesenteric artery flow (+80 mL/min), stroke work (+561 mmHg/mL/m2), and left ventricular power output (+55.7 mmHg/L/min/m2). Corresponding increases were not observed in controls. We conclude that administration of a constant rate infusion of enalaprilat during resuscitation can be accomplished without causing a hypotensive crisis. Since enalaprilat significantly improved cardiovascular status including mesenteric perfusion even during intentional hypotension, it has potential value for improving the treatment of trauma patients.

Teaching undergraduate research: The one-room schoolhouse model.

Undergraduate research in the biochemistry, cell, and molecular biology program at Drake University uses apprenticeship, cooperative‐style learning, and peer mentoring in a cross‐disciplinary and cross‐community educational program. We call it the one‐room schoolhouse approach to teaching undergraduate research. This approach is cost effective, aids learning, supports the development of science and transferable management skills, is productive, and supports diversity. It allows a small set of faculty to involve large numbers of students in research and maintain a productive scholarship program. It provides students with skills in scientific research and transferable skills that they apply to a wide set of careers.

Enalaprilat improves systemic and mesenteric blood flow during resuscitation from hemorrhagic shock in dogs.

We investigated the systemic and mesenteric cardiovascular effects of administering enalaprilat during resuscitation from hemorrhage. Dogs were hemorrhaged (mean arterial pressure [MAP] 40–45 mmHg for 30 min, then 30–35 mmHg for 30 min) and were then resuscitated with intermittent lactated Ringers solution (200 mL/kg/h during first 40 min, and 60 mL/kg/h during the following 130 min, MAP 75–80 mmHg). A constant-rate infusion of saline with or without enalaprilat (0.02 mg/kg/h) was initiated after 40 min of resuscitation. Blood flows declined with hemorrhage, increased with resuscitation, and then declined during the initial 40 min of resuscitation. Enalaprilat administration resulted in blood flow increases not seen in the controls (ending values for cardiac index: 2.8 ± 0.4 L/min/m2 vs. 1.6 ± 0.3 L/min/m2; celiac arterial flow 314 ± 66 L/min/m2 vs. 139 ± 13 mL/min/m2; and portal venous flow 596 ± 172 L/min/m2 vs. 414 ± 81 mL/min/m2 for enalaprilat versus controls, respectively). The greater flows with enalaprilat appeared to be due to prevention of the increases in afterload noted in the controls (ending arterial elastance values 3.73 ± 0.97 mmHg/m2/mL vs. 7.74 ± 1.80 mmHg/m2/mL for enalaprilat versus controls, respectively). We conclude that administration of a constant-rate infusion of enalaprilat during resuscitation can be used to improve systemic and mesenteric blood flow.

Airflow-based PCO2 monitoring delivers O2 and removes CO2 from the monitored environment.

Previous investigation has suggested that the use of airflow-based gastrointestinal intraluminal PCO2 (GI PiCO2) monitoring systems may affect the local tissue microenvironment, making it not representative of the organ system as a whole. Therefore, we investigated the effects of using an airflow-based PCO2 monitoring system in a sealed environment. A 250-mL Erlenmeyer flask was filled with 10% CO2/90% N2 and was sealed with probes in place. Using a fiber-optic (Neotrend®, Diametrix Medical, St. Paul, MN) system, the PCO2 and PO2 were continuously monitored with and without the airflow-based (Tonocap®, Tonometrics, Datex-Ingstrom, Helsinki, Finland) system operating. PCO2 and PO2 remained constant when the airflow-based system was not in operation. PCO2 decreased 25.3 mmHg and PO2 increased 30 mmHg from a starting value of 0 mmHg when the airflow-based system was in operation for 12 h. The use of airflow-based methods for determining GI PiCO2 may influence the values obtained. Nonsample removing techniques such as fiber-optic methods for monitoring GI PiCO2 are preferable because they neither deliver O2 to nor remove CO2 from the local microenvironment.

A note on the enumeration of Kekulé structures in a class of coronoids

Abstract An extension of the Gordon-Davison algorithm to the enumeration of Kekule valence structures in a class of simple coronoids is outlined.