The generality of architectural isomerism in designer inclusion frameworks.

We describe herein new structural isomers of a lamellar host system based on organodisulfonate "pillars" that connect opposing hydrogen-bonded sheets, consisting of topologically complementary guanidinium (G) ions and sulfonate (S) groups, to generate inclusion cavities between the sheets. These new isomers-zigzag brick, double brick, V-brick, and crisscross bilayer-expand significantly on our earlier report of architectural isomerism displayed by the discrete bilayer and simple brick forms. We demonstrate here that the discrete bilayer-simple brick isomerism, which was limited to several host-guest combinations based on the G(2)(4,4'-biphenyldisulfonate) host and one pair of compounds based on the G(2)(2,6-naphthalenedisulfonate), can be generalized to other organodisulfonate pillars. Furthermore, in many cases the selectivity toward the different framework isomers reflects a rather systematic templating role of the guest molecules and host-guest recognition during assembly of the lattice. We also describe a convenient approach to identifying and classifying the innumerable possible host architectures based upon the pillar projection topologies for the GS sheets and the intersheet connectivities. The discovery of these new architectures reveals a structural versatility for this class of materials that exceeds initial expectations and observations. Each topology produces different connectivities between the sheets in the third dimension that endows each framework isomer with uniquely shaped and sized inclusion cavities, enabling this host system to conform readily to different guests. The unlimited number of architectures available, combined with the inherent conformational softness and structural tunability of these host lattices, suggests a near universality for the GS system with respect to guest inclusion.

Postinfarctional ventricular septal rupture. Clinical approach and surgical results.

This study represents an analysis of 13 cases of ruptured interventricular septum occurring as a complication of myocardial infarction. The cases considered appeared to divide themselves into two groups. One group survived the septal rupture for weeks or months and underwent surgery in the chronic stage. The patients in the other group were diagnosed and underwent surgery in the acute stage because of clinical indications of a rapidly deteriorating situation. There were four serious complications resulting from extensive cardiac catheterization and angiographic procedures. Those patients who were diagnosed using bedside balloon-directed catheterization techniques had no serious complications. The data indicate that: (1) the diagnostic approach should be executed quickly and by simple methods; (2) it is possible to operate successfully upon these patients in the acute phase of their disease; and (3) because of the unpredictable course and rapid deterioration, these alternatives should be strongly considered.

Aortic stenosis, angina, and coronary artery disease. Interrelations.

Sixty-nine patients over age 35 with severe valvular aortic stenosis were investigated for concomitant coronary artery disease. Forty (57.9%) had clinical angina pectoris. Sixteen (23.2%) had significant coronary occlusive disease by arteriography. Of those with angina, 13 patients (32.5) had significant coronary arterial obstruction, while in the pain-free group only (10.3%) had occlusive coronary disease. It is concluded that patients with severe aortic stenosis who are free of angina have only a small, but definite, chance of having significant coronary disease.