Severe Noncardiogenic Pulmonary Edema Secondary to Massive Verapamil Overdose and Treatment with Venovenous Extracorporeal Membrane Oxygenation.

Calcium channel blocker (CCB) poisoning frequently presents with cardiovascular complications such as cardiogenic shock and arrhythmia. We present a case of massive verapamil overdose causing refractory noncardiogenic pulmonary edema successfully treated with extracorporeal membrane oxygenation. To our knowledge, this is the first case with these features reported in literature. A 27-year-old female patient presented with an overdose of 18,000 mg of verapamil. Her clinical condition deteriorated to severe hypoxic respiratory failure despite being treated with calcium, high-dose insulin, and full invasive ventilation support. She eventually required venovenous extracorporeal membrane oxygenation (VV-ECMO) for three days with full recovery. Large ingestion of verapamil could lead to noncardiogenic pulmonary edema. VV-ECMO might play an important role to support the treatment in severe cases with refractory hypoxia.

De novo proteins from designed combinatorial libraries.

Combinatorial libraries of de novo amino acid sequences can provide a rich source of diversity for the discovery of novel proteins with interesting and important activities. Randomly generated sequences, however, rarely fold into well-ordered proteinlike structures. To enhance the quality of a library, features of rational design must be used to focus sequence diversity into those regions of sequence space that are most likely to yield folded structures. This review describes how focused libraries can be constructed by designing the binary pattern of polar and nonpolar amino acids to favor proteins that contain abundant secondary structure, while simultaneously burying hydrophobic side chains and exposing hydrophilic side chains to solvent. The "binary code" for protein design was used to construct several libraries of de novo proteins, including both alpha-helical and beta-sheet structures. The recently determined solution structure of a binary patterned four-helix bundle is well ordered, thereby demonstrating that sequences that have neither been selected by evolution (in vivo or in vitro) nor designed by computer can form nativelike proteins. Examples are presented demonstrating how binary patterned libraries have successfully produced well-ordered structures, cofactor binding, catalytic activity, self-assembled monolayers, amyloid-like nanofibrils, and protein-based biomaterials.

Structure and dynamics of de novo proteins from a designed superfamily of 4-helix bundles.

Libraries of de novo proteins provide an opportunity to explore the structural and functional potential of biological molecules that have not been biased by billions of years of evolutionary selection. Given the enormity of sequence space, a rational approach to library design is likely to yield a higher fraction of folded and functional proteins than a stochastic sampling of random sequences. We previously investigated the potential of library design by binary patterning of hydrophobic and hydrophilic amino acids. The structure of the most stable protein from a binary patterned library of de novo 4-helix bundles was solved previously and shown to be consistent with the design. One structure, however, cannot fully assess the potential of the design strategy, nor can it account for differences in the stabilities of individual proteins. To more fully probe the quality of the library, we now report the NMR structure of a second protein, S-836. Protein S-836 proved to be a 4-helix bundle, consistent with design. The similarity between the two solved structures reinforces previous evidence that binary patterning can encode stable, 4-helix bundles. Despite their global similarities, the two proteins have cores that are packed at different degrees of tightness. The relationship between packing and dynamics was probed using the Modelfree approach, which showed that regions containing a high frequency of chemical exchange coincide with less well-packed side chains. These studies show (1) that binary patterning can drive folding into a particular topology without the explicit design of residue-by-residue packing, and (2) that within a superfamily of binary patterned proteins, the structures and dynamics of individual proteins are modulated by the identity and packing of residues in the hydrophobic core.

NMR assignment of S836: a de novo protein from a designed superfamily.

Libraries of de novo proteins provide an opportunity to explore the structural potential of biological macromolecules that have not been biased by billions of years of evolutionary selection. Characterization of individual members of such libraries provides insight into the diversity of structure and dynamics accessible to nascent protein superfamilies in the absence of evolutionary optimization. Here we report the backbone and side chain chemical shifts of protein S836 from a superfamily of designed 4-helix bundles.