Frontmatter -- FOREWORD -- Official Sponsors and Donors -- YOUNG INVESTIGATOR AWARDEES NINTH WORKSHOP ON VITAMIN D -- Vitamin D Workshop. Career Recognition Awardees -- Contents -- Chemistry of Vitamin D -- Shape and Conformation of Vitamin D. 11-Fluoro-1a-Hydroxyvitamin D3: The Quest for Experimental Evidence of the Folded Vitamin D Conformation -- Conformation and Related Topological Features of Vitamin D: Structure-Function Relationships -- Chemical Conversion of Vitamin D3 to Calcitriol Lactone -- Design, Synthesis, and SAR of Some 1-Substituted A-Ring Analogs of Calcitriol -- A General Synthetic Route to A-Ring Hydroxylated Vitamin D Analogs from D-Pentoses -- Retiferols. Design and Synthesis of the New Class of Vitamin D Analogs -- Introduction of 1a-Hydroxyl Group to Provitamin D Causes New Photoisomerization Reactions -- Synthesis and Determination of the Configurations of the 23-Hydroxylated Metabolites of Calcipotriol (MC 903) and their Epimers -- Syntheses of Potential Inhibitors of 25-Hydroxyvitamin D3-1a-Hydroxylase: A-Ring Analogs -- Metallic Complexes of Hydroxylated Derivatives of Vitamin D3 -- A New Route to the Lythgoe-Roche's A-Ring Precursor of 1a,25-Dihydroxyvitamin D3 -- Structure-Activity Studies of Fluorinated Vitamin D Analogs -- An In Vitro Model of Previtamin D Photosynthesis as Possible Monitor of Ozone Depletion -- Synthesis of 24-Hydroxy-Vitamin D Analogues -- Chromatographic Isolation and Spectroscopic Characterization of the Photoisomers of 1a,25-Dihydroxy-Provitamin D3 -- A New Route to the Vitamin D Triene System -- Studies on the Synthesis of 19-Norprevitamin D3 Analogues -- Structure/Function Studies of Vitamin D Steroids -- The Need for New Vitamin D Analogues: Mechanisms of Action and Clinical Applications -- Future Prospects for Vitamin D Analogs -- Chemistry and Biology of 22,23-yne Analogs of Calcitriol -- Chemistry and Biology of 23-oxa-aro- and 23-thia-aro-Vitamin D Analogues with High Antiproliferative and Low Calcemic Activity -- Activity of Vitamin D Analogs in Co-Transfected COS-7 Cells -- Synthesis and Biological Character of 1?-Hydroxylated Vitamin D3 Analogs -- Biological Activity and Conformational Analysis of 1?,25-Dihydroxyvitamin D3 and its Analogues -- Topological Mimics of the 6-s-cis-Conformer of 1a,25-Dihydroxyvitamin D3 Based on the Provitamin D Skeleton -- Chemistry and Biology of Highly Active 22-oxy Analogs of 20-epi Calcitriol with Very Low Binding Affinity to the Vitamin D Recepto -- New Discoveries in Vitamin D Related Compounds -- Modelling of Previtamin D Photosynthesis in View of its Conformational Flexibility -- Active Vitamin D Analogs with Side Chain Hydroxyl Group Occupying Diverse Spatial Region -- Synthesis and Biological Activity of 23-oxa Vitamin D Analogues -- Synthesis and Biological Activity of 20-Hydroxylated Vitamin D Analogues -- 20-Methyl Vitamin D Analogues -- 2?-Substituted Calcitriols and Other A-Ring Substituted Analogues - Synthesis and Biological Results -- Syntheses and Biological Activity of 1ß-Substituted Active Vitamin D3 Analogs -- Vitamin D Binding Protein -- Probing the Vitamin D-Sterol Binding Domain of Human Vitamin D-Binding Protein: Chemical Modification of Specific Amino Acid Residues -- Crystallization and Preliminary X-Ray Investigation of Vitamin D-Binding Protein from Human Serum -- Effects of Vitamin D-Binding Proteins on Biological Functions of 1 a,25-Dihydroxyvitamin D3 Analogues -- Vitamin D Hydroxylases: Biochemistry and Regulation -- Differences of the Regulation of 24-Hydroxylase Gene Expression in the Kidney and Intestine -- Regulation of the Ferredoxin Component of Renal Hydroxylases at the Transcriptional and Postradiational Level and of the Protein Inhibitor of Cyclic AMP-Dependent Kinase -- Site and Rate of Hydroxylation of 1a-OH-D3 Analogs by CYP27 Not Altered by Increasing Length or Changing Orientation of Vitamin D3 Side Chain -- Protein Kinase C Up-Regulates 1 a,25-Dihydroxyvitamin D3-Induced Expression of