Directional coronary atherectomy at the Toronto and Mount Sinai Hospitals: report of the initial 120 procedures.

OBJECTIVE: To assess the procedural success and complication rates of the first 120 directional coronary atherectomy cases performed at two Toronto hospitals. DESIGN AND SETTING: Case series in tertiary referral centres. PATIENTS: One hundred and thirteen patients in whom 120 atherectomy procedures were attempted between July 1990 and April 1992. INTERVENTION: Directional coronary atherectomy. MAIN RESULTS: Angiographic success was obtained in 115 of 120 procedures (96%) involving 117 of 123 lesions (95%). Procedural success (angiographic success without death, myocardial infarction or coronary bypass surgery) was obtained in 110 of 120 procedures (92%). Adjunctive balloon angioplasty was required in 20 procedures (17%). There was one death at 36 h in an elderly patient who underwent an emergency procedure while in cardiogenic shock. Periprocedural non-Q wave myocardial infarction occurred in five patients. There were no Q wave myocardial infarctions. Three patients required coronary bypass surgery prior to discharge and vascular complications occurred in five patients. CONCLUSIONS: Directional coronary atherectomy can be performed with procedural success and complication rates comparable to conventional balloon angioplasty. Randomized trials are underway to determine if atherectomy results in a lower restenosis rate.     

Pitfalls in establishing the diagnosis of deep venous thrombophlebitis by indium-111 platelet scintigraphy

Forty-seven 111In-platelet scintigraphs (In-PS) were analyzed retrospectively to identify sources of diagnostic error and to optimize the diagnostic criteria for active deep venous thrombophlebitis (DVT). The results of In-PS were compared with contrast venography, additional diagnostic studies, and clinical outcome. Three patterns of platelet localization emerged as the best predictors of active DVT: (a) focal or (b) linear 4-hr localization, or (c) an asymmetric blood-pool pattern on 4-hr imaging that evolved into a focal or linear pattern by 16 to 24 hr. All false-positive studies had abnormal patterns confined to the inguinal region at 24 hr. All patients with false-negative studies had received heparin between 4 and 24 hr. The potential pitfalls encountered in the evaluation of the iliac, femoral, and popliteal veins are reviewed and the importance of delayed imaging in selected cases is emphasized.     

Benzazepinone calcium channel blockers. 2. Structure-activity and drug metabolism studies leading to potent antihypertensive agents. Comparison with benzothiazepinones.

As part of a program to discover potent antihypertensive analogues of diltiazem (3a), we prepared 1-benzazepin-2-ones (4). Benzazepinones competitively displace radiolabeled diltiazem, and show the same absolute stereochemical preferences at the calcium channel receptor protein. Derivatives of 4 containing a trifluoromethyl substituent in the fused aromatic ring show potent and long-acting antihypertensive activity. Studies of the metabolism of 4 lead to the metabolically stable antihypertensive calcium channel blockers 5a and 5c. Benzazepinone 5a is a longer acting and more potent antihypertensive agent than the second generation diltiazem analogue TA-3090 (3e).     

Sensitivity of intracellular signals responsible for cell cycle progression to cyclosporine.

Within the cascade of intracellular activation signals triggering T lymphocyte effector response to alloantigen is a cytoplasmic protein, ADR, that activates DNA replication in isolated nuclei. Quantitative changes in ADR (exclusive to activated cells) regulate cell cycle progression and may indicate changes in intracellular proliferative control. The present communication documents that inhibition of ADR activity reflects the in vitro immunosuppressive effects of Cyclosporine. CsA inhibition of both proliferation and generation of ADR was concentration-dependent and occurred only in the G0 phase of the cell cycle. Drug addition did not affect G1 cells. ADR generation was inhibited both by CsA and by PGE2 alpha, possibly via effects on calcium-dependent activation pathways confined to G0/G1 transition. On the other hand, ADR generation was not inhibited by the immunosuppressive agents 6-mercaptopurine, Enisoprost (a PGE1 analog), or FK506. ADR activity was sensitive to aprotinin, which typically inhibits serine proteases. Using an enzymatic assay to quantitate serine protease activity (SPA) following PHA stimulation revealed that ADR content inversely correlated with SPA: ADR was only present in activated cells; SPA was highest in resting cells and decreased after PHA stimulation. The PHA-induced fall in SPA activity was inhibited by CsA, consistent with the failure to generate ADR. Like ADR, SPA was sensitive to PGE2 alpha and quantitatively unaffected by 6-mercaptopurine, Enisoprost, or FK506. Thus, ADR and SPA may represent opposing components of a cytoplasmic signaling cascade the balance of which reflects the level of immunosuppression, and thus represents a focus for in vitro evaluation of the immunologic response of allografted patients to cyclosporine.     

Separation and Characterization of Human Neutrophil Granules

Human blood neutrophilic leukocytes were separated and purified by modifications of the Hypaque/Ficoll and dextran separation methods, resulting in a suspension which was greater than 96% neutrophils. Neutrophils were prepared in 0.34 M sucrose containing heparin and were clarified of nongranular debris by sequential passage through polycarbonate filters of pore size 5 μ and 2 μ. Isopycnic sucrose gradients of such filtrates revealed three major bands. The gradient separated fractions were studied by electron microscopy including peroxidase cytochemistry and by enzyme assay for myeloperoxidase (MPO), β-glucuronidase, muramidase alkaline phosphatase and acid phosphatase utilizing both p-nitrophenylphosphate (pnp) and β-glycerophosphate as substrates. Peroxidase-positive granules were observed at both density 1.22 (band A) and density 1.20 (band B). Three peroxidase-negative granules were identified: the round or oval peroxidase-negative granule of density 1.22 (band A) and two smaller granules, distinguishable by size and shape at density 1.18 (band C). Band C granules contain crystalloid inclusions. Peaks of muramidase activity coincided with bands A and C, suggesting the presence of muramidase in the peroxidase-negative granules of density 1.22 and in one or both of the peroxidase-negative granules at density 1.18. β-Glucuronidase was distributed like MPO, with a major peak in band B and a minor peak in band A. Acid β-glycerophosphatase was largely in band A. Acid pnp phosphatase was nonspecifically associated with soluble nongranular protein which always remained at the origin of sucrose gradients. Alkaline phosphatase was not granule associated and sedimented alone to density 1.145, which is highly suggestive of a cytoplasmic membrane localization for this enzyme.     

Structural studies on H-2Db and H-2Kd molecules indicate that murine major histocompatibility b and d haplotype alloantigens share structural features

Structural properties of the H-2D^b and H-2K^d murine major histocompatibility complex (MHC) antigens were examined by radiochemical methods. Radiolabelled preparations of the H-2D^b and H-2K^d antigens were obtained by indirect immune precipitation of NP-40 lysates of the lymphoid tumor cell lines EL-4 (H-2^b) and C14 (H-2^d), respectively. After preparation of the 37,000 molecular weight papain fragment the antigens were cleaved with CNBr. The H-2K^d antigen yielded four major CNBr fragments whereas the H-2D^b molecule provided six. These CNBr fragments were subjected to partial NH₂-terminal amino acid sequence analysis and aligned by homology to the H-2K^b glycoprotein. Comparison of the structural properties of the H-2K^d and H-2D^b molecules with previously published data on the other known major transplantation antigens of the b and d haplotypes (H-2K^b, H-2D^d and H-2L^d) reveal a marked structural similarity. First, the data show that certain methionine residues have been highly conserved and that cleavage by CNBr at these positions provides an initial strategy for the study of these molecules. Secondly, disulfide-linked peptides obtained after CNBr cleavage could be aligned and the data suggest the presence of disulfide bridges in homologous positions. Third, after CNBr cleavage both the H-2K^d and H-2D^b molecules yielded two glycopeptides which were homologous to glycopeptides from the H-2K^b molecule. Fourth, overall homology for a limited number of comparable positions is about 81% between the H-2K^b and H-2K^d gene products and 88% between the H-2K^b and H-2D^b gene products.     

Detection of beta-defensins secreted by human oral epithelial cells

Human beta-defensins are antimicrobial peptides that may be critical in the innate immune response to infection. hBD1 and hBD2 are expressed in oral epithelial cells and are detected near the surface of oral tissue, consistent with a role in the epithelial protective barrier function. In this report, we examine secretion of beta-defensins in vitro and in biological fluid using ProteinChip(R) Array, surface enhanced laser desorption/ionization (SELDI) technology combined with time-of-flight mass spectrometry. We show that the 47-amino acid form of hBD1 and the 41-amino acid form of hBD2 are the major secreted forms. These forms are both expressed and secreted under conditions anticipated from previous analysis of beta-defensin mRNAs; specifically, hBD1 is detected in culture supernatant from both unstimulated and stimulated cells, and hBD2 is detected only in stimulated cells. Identity of hBD1 and hBD2 was confirmed by immunocapture on the ProteinChip surface. Both peptides are also present in gingival crevicular fluid that accumulates between the tissue and tooth surface, although hBD1 is also found in several smaller forms suggesting extracellular proteolysis. This methodology offers several technical advantages for detection of defensins in biological fluids, including ease and speed of screening, no need for HPLC preliminary processing, and small sample size.