Spring 1958

Dedication of Turf Clippings to Robert Williams (1) Picture - Stockbridge Turf majors (2) Title page and contents (3) Greetings from Dean Sieling - College of Agriculture (4) Outstanding Men in Turfgrass Honored (4) Word From the Editor of Turf Clippings (5) Message From the 1958 Winter School President (6) Summary of 1958 University of Massachusetts Turfgrass Conference - Al Radko (6-9) Importance of Superintendences Associations - Anthony B. Caranci (10) Picture - Turf Grass Interest Stretch from Coast to Coast (11) Picture - 1958 Winter School for Turf Managers (12) Golf Courses in California - James C. Scott (13) The Constant Battle - Joseph Troll (13) Recognition of the Golf Course Superintendent - Frederick Bove (14-15) 1958 Winter School Comments (16) Maintenance of Insurance Grounds - George J. Moore Jr. (17-18) Don\u27t Get Caught Short - Bruce Silven (19-20) We Have had It - They Now Have it - These Two Shall Have it - Orville O. Clapper (21) The Golf Course Superintendent - Prof. L. S. Dickinson (22-23) Picture - Winter School Alumni Meet at Conference (24) Cartoons (25) Cost of Lawn and Golf Course Construction - Geoffrey Cornish (26-27) Turf Club News (28-29) 1957 Horticulture Show Winner (30) Frosting on the Cake (30) Number One Graduate (31) 1957 Stockbridge Turf majors - Work (32) Turf management Club Associate Memberships (32

Controlled release of 1-hydroxyethylidene diphosphonate: in vitro assessment and effects on bioprosthetic calcification in sheep tricuspid valve replacements

Calcification (CALC) is the most frequent cause of the clinical failure of bioprosthetic valves (BHV's). Controlled-release (paravalvar) administration of the anticalcification agent ethanehydroxydiphosphonate (EHDP), as either Na2EHDP or in combination (1:1) with the less soluble CaEHDP, from a silicone rubber matrix (20% w/w EHDP) was studied both in vitro and in vivo for the prevention of BHV CALC. Seventeen sheep (6-7 months old, male, Suffolk) underwent tricuspid valve replacement using Hancock I, 25 mm porcine aortic bioprostheses. BHV explant evaluation after 16-20 weeks revealed that two of the 7 control BHV were calcified (139 +/- 20.8 [mu]gCa2+/mg of tissue), while none of the 9 BHV retrieved from animals receiving controlled release EHDP demonstrated CALC (4.41 +/- 1.09 [mu]g Ca2+/mg of tissue). No adverse effects of EHDP on bone or calcium metabolism were noted. The cumulative percent of EHDP released per electron microprobe analysis was 40.4% +/- 9.68 (Na, CaEHDP) to 79.0% +/- 4.82 (Na2EHDP) in vivo compared to 35.7% +/- 7.72 and 78.6 +/- 11.1 in vitro, respectively. Assessment of the Young's modulus (Y) using thermomechanical analysis (TMA) revealed a 1.5-fold (Silastic Q7-4840) to 9.5-fold (Silastic 382) increase in Y following drug loading. The Y for explanted, Silastic Q7-4840 polymer matrices ranged from 2.84 x 104 to 5.57 x 105 dyne/cm2. In vitro osmotic related matrix swelling of the Na2EHDP loaded, unsealed matrices (20% w/w) after 75 days was minimized to a 35.8% increase in weight due to coincorporation of CaEHDP with Na2EHDP in a 1:1 ratio and was further reduced (22.2% increase in weight) by sealing 76% of the releasing surface, compared to Na2EHDP matrices which demonstrated a 414% and 141% increase in weight, respectively.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27902/1/0000322.pd