The influence of anesthetic choice, PaCO2, and other factors on osmotic blood-brain barrier disruption in rats with brain tumor xenografts.

Unlabelled: Increasing the delivery of therapeutic drugs to the brain improves outcome for patients with brain tumors. Osmotic opening of the blood-brain barrier (BBB) can markedly increase drug delivery, but achieving consistent, good quality BBB disruption (BBBD) is essential. We evaluated four experiments compared with our standard isoflurane/O2 protocol to improve the quality and consistency of BBBD and drug delivery to brain tumor and normal brain in a rat model.

Improving drug delivery to intracerebral tumor and surrounding brain in a rodent model: a comparison of osmotic versus bradykinin modification of the blood-brain and/or blood-tumor barriers.

Objective: To compare transient blood-brain barrier disruption (BBBD) by hypertonic mannitol with pharmacological modification of the blood-tumor barrier by the vasoactive peptide bradykinin for delivery of small and large agents to nude rat intracerebral xenografts.

Methods: Female nude rats (n = 104) with 6-day intracerebral human small cell lung carcinoma tumors were treated using BBBD (n = 24), intracarotid bradykinin (n = 38), or saline (controls, n = 32) administered intra-arterially. During or immediately after infusion, the rats were given radiolabeled agent (methotrexate or dextran 70; Dupont NEN, Boston, MA).

Muscle weakness during tricaine anesthesia.

An isolated preparation of tadpole tail muscle was used to assess the peripheral effects of tricaine (3-aminobenzoic acid ethyl ester) at anesthetic concentrations and under physiological conditions. The drug effect on the electrically-evoked twitch was tested using short-pulse durations that elicited synaptically mediated effects or longer-duration pulses that stimulated the muscle directly. Tricaine reduced both types of response anesthetic and even subanesthetic concentrations.

The effect of nitrous oxide on left ventricular pump performance and contractility in patients with coronary artery disease: effect of preoperative ejection fraction.

To elucidate the effects of nitrous oxide (N2O) on left ventricular (LV) pump performance and contractility, 28 patients undergoing coronary artery bypass graft surgery were studied, of whom 15 had depressed global LV function at preoperative catheterization. Transesophageal echocardiography and simultaneous hemodynamic measurements were used to assess LV preload, afterload, and systolic performance during inhalation of 100% oxygen (O2) and 60% N2O:40% O2. Systolic function indices were expressed as a percent of the predicted value for observed end-systolic stress to provide estimates of LV contractility.