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Interleukin-2 (IL-2) is a cytokine that produces an in vivo immunostimulating effect when given systemically. This action may arise from stimulating the growth and expansion of cytotoxic T cells that in turn activate natural killer cells to attack tumors such as malignant melanoma and renal cell carcinoma. Therefore, administration of high-dose IL-2 can invoke an antitumor response in some patients. However, high-dose IL-2 induces severe and sometimes life-threatening toxicity, including vascular leak syndrome, hypotension, fever, and end-organ damage. Renal, hepatic, pulmonary, cardiac, and neurologic side effects have been described. Patients receiving IL-2 therefore require close monitoring to detect and treat life-threatening complications arising from treatment. The authors describe the steps taken to begin an IL-2 biotherapy program in a small ICU at a regional comprehensive cancer center. The addition of “elective” IL-2 admissions to the ICU has had a beneficial effect on stabilizing the daily census. In addition, it has brought a new cohort of patients who are highly appreciative of the care they receive and provides the nursing staff a new opportunity to develop expertise with cancer biotherapy.

Blockade of voltage-gated sodium (Na+) channels by local anesthetics represents the main mechanism for inhibition of impulse propagation. Local anesthetic-induced potassium (K+) channel inhibition is also known to influence transmission of sensory impulses and to potentiate inhibition. K+channels involved in this mechanism may belong to the emerging family of background tandem pore domain K+channels (2P K+channels). To determine more precisely the effects of local anesthetics on members of this ion channel family, we heterologously expressed the 2P K+channels TASK-2 (KCNK5), TASK-1 (KCNK3), and chimeric TASK-1/TASK-2 channels in oocytes of Xenopus laevis. TASK-2 cDNA-transfected HEK 293 cells were used for single-channel recordings. Local anesthetic inhibition of TASK-2 was dose-dependent, agent-specific, and stereoselective. The IC50values for R-(+)-bupivacaine and S-(–)-bupivacaine were 17 and 43 μM and for R-(+)-ropivacaine and S-(–)-ropivacaine, 85 and 236 μM. Lidocaine (1 mM) inhibited TASK-2 currents by 55 ± 4%, whereas its quaternary positively charged analog N-ethyl lidocaine (QX314) had no effect. Bupivacaine (100 μM) decreased channel open probability from 20.8 ± 1.6% to 5.6 ± 2.2%. Local anesthetics [300 μM R-(+)-bupivacaine] caused significantly greater depolarization of the resting membrane potential of TASK-2-expressing oocytes compared with water-injected control oocytes (15.8 ± 2.5 mV versus 0.1 ± 0.05 mV; p< 0.001). Chimeric TASK-1/TASK-2 2P K+channel subunits that retained pH sensitivity demonstrated that the carboxy domain of TASK-2 mediates the greater local anesthetic sensitivity of TASK-2. These results show that clinically achievable concentrations of local anesthetics inhibit background K+channel function and may thereby enhance conduction blockade.

Opium poppy (Papaver somniferum) contains a large family of tyrosine/dihydroxyphenylalanine decarboxylase (tydc) genes involved in the biosynthesis of benzylisoquinoline alkaloids and cell wall-bound hydroxycinnamic acid amides. Eight members from two distinct gene subfamilies have been isolated, tydc1, tydc4, tydc6, tydc8, and tydc9 in one group and tydc2, tydc3, and tydc7 in the other. The tydc8 and tydc9 genes were located 3.2 kb apart on one genomic clone, suggesting that the family is clustered. Transcripts for most tydc genes were detected only in roots. Only tydc2 and tydc7 revealed expression in both roots and shoots, and TYDC3 mRNAs were the only specific transcripts detected in seedlings. TYDC1, TYDC8, and TYDC9 mRNAs, which occurred in roots, were not detected in elicitor-treated opium poppy cultures. Expression of tydc4, which contains a premature termination codon, was not detected under any conditions. Five tydc promoters were fused to the beta-glucuronidase (GUS) reporter gene in a binary vector. All constructs produced transient GUS activity in microprojectile-bombarded opium poppy and tobacco (Nicotiana tabacum) cell cultures. The organ- and tissue-specific expression pattern of tydc promoter-GUS fusions in transgenic tobacco was generally parallel to that of corresponding tydc genes in opium poppy. GUS expression was most abundant in the internal phloem of shoot organs and in the stele of roots. Select tydc promoter-GUS fusions were also wound induced in transgenic tobacco, suggesting that the basic mechanisms of developmental and inducible tydc regulation are conserved across plant species.

During early development, there are numerous instances where a bipotent progenitor divides to give rise to two progeny cells with different fates. The Notch gene of Drosophila and its homologues in other metazoans have been implicated in many of these cell fate decisions. It has been argued that the role of Notch in such instances may be to maintain cells in a precursor state susceptible to specific differentiating signals. This has been difficult to prove, however, due to a lack of definitive markers for precursor identity. We here perform molecular and morphological analyses of the roles of Notch in ovarian follicle cells during Drosophila oogenesis. These studies show directly that constitutively active Notch arrests cells at a precursor stage, while the loss of Notch function eliminates this stage. Expression of moderate levels of activated Notch leads to partial transformation of cell fates, as found in other systems, and we show that this milder phenotype correlates with a prolonged, but still transient, precursor stage. We also find that expression of constitutively active Notch in follicle cells at later stages leads to a defect in the anterior-posterior axis of the oocyte.

1. The potency of agonists and competitive antagonists on the two expressed forms of the nicotinic acetylcholine receptor (adult or junctional subtype, ε-AChR; fetal or extrajunctional subtype, γ-AChR) have not previously been compared systematically in homogeneous receptor preparations. 2. Each subtype of the receptor was expressed separately in Xenopusoocytes by cytoplasmic injection of combinations of RNA transcribed in vitro. The presence of each type of receptor was confirmed by single-channel recordings. Expressing oocytes were assayed using discontinuous, single-electrode voltage clamp by measuring peak currents in response to test compounds. 3. The extrajunctional subtype was more potently activated by the nicotinic agonist dimethylphenyl piperazinium iodide (DMPP) than was the junctional form. There was no statistically significant difference in potency between the two subtypes for other nicotinic agonists (nicotine, cytisine and succinylcholine). The rank order of potency for ε-AChR was succinylcholine>cytisine>DMPP>nicotine, and that for γ-AChR was DMPP>cytisine>succinylcholine>nicotine. 4. Two agonists (cytisine and succinylcholine) displayed six- to eight-fold greater intrinsic activity in activating ε-AChR over γ-AChR. There was no difference between the two forms of receptor in efficacy for nicotine. 5. The extrajunctional form was much more potently inhibited by the steroidal competitive antagonist pancuronium than was the junctional receptor. However, there was no significant difference in potency of inhibition by the curariform drug atracurium. 6. Contrary to previous reports, there is no consistent relation between the effect of agonists and antagonists and the subtype of receptor. These data suggest that the resistance or sensitivity to these agents seen in various clinical settings are related to other cellular factors.