What is already known about this subject• SHPT is highly prevalent in the hemodialysis patient population.It is often treated with vitamin D analogs. There is a need for evidence of the treatment effect of vitamin D analogs on hard endpoint skeletal and cardiovascular outcomes in predialysis CKD patients. What this study adds• The financial expense of treating SHPT (as a complication of CKD) may be cost effective, based on observational data. In addition to the need to establish a causal link between drug therapy for SHPT and reduction in hard endpoint cardiovascular outcomes, future randomized studies are needed to determine the preferred agent, PTH treatment goal, stage of the disease at which to initiate treatment, and impact on mortality.ABSTRACT BACKGROUND: There has been an emphasis over the last several years to identify and treat chronic kidney disease (CKD) and its complications as they evolve rather than waiting until the patient reaches end-stage renal disease (ESRD), also known as CKD stage 5. The number of patients who will be identified and prescribed therapies for complications such as secondary hyperparathyroidism (SHPT) is greater than initially proposed.OBJECTIVE: To review the pathways, complications, management, and estimated treatment costs of CKD-related SHPT.METHODS: An electronic literature search of MEDLINE (January 1980 through January 2007) was conducted for English-language publications using the base search term secondary hyperparathyroidism. To refine subsequent searches, the authors added Boolean operators to the following secondary and tertiary search terms: parathyroid hormone, chronic kidney disease, renal osteodystrophy, adynamic bone disease, vascular calcification, cardiovascular disease, vitamin D, vitamin D analogs, hypercalcemia, hyperphosphatemia, calcimimetics, costs, prevalence, and economics.RESULTS: The initial MEDLINE search produced 278 relevant articles. After refining the search terms, the authors triaged the results for English-language publications relevant to the discussion of SHPT and its complications in CKD, eliminating 149 publications. The remaining 129 publications were accepted for review. These articles represent a growing body of primarily observational evidence that demonstrates that elevated intact parathyroid hormone (PTH) levels cause deleterious physiological results across a variety of organ systems, including the cardiovascular and skeletal systems. Specific complications associated with SHPT are left ventricular hypertrophy (LVH), renal osteodystrophy (ROD), and extraskeletal calcification. Medical management of the PTH/vitamin D/calcium and phosphorus imbalances in SHPT focus on regulating PTH levels via vitamin D therapy. The class of calcimimetics is a newer treatment modality that has favorable effects on biochemical laboratory values, such as serum calcium and phosphorus levels, but current data do not show differences on hard endpoint patient-oriented outcomes compared with standard generic agents. CONCLUSIONS: SHPT causes skeletal and ca...

The spectroscopic properties and photochemical behavior of molecules having 2-ethynylbiphenyl or 2-phenyldiphenylacetylene structures are reported. These molecules undergo photocyclization reactions to yield phenanthrene and dihydrophenanthrene products via putative isophenanthrene (cyclic allene) intermediates. Phenanthrene formation from the isophenanthrene intermediates does not occur via a unimolecular sigmatropic hydrogen shift, but rather by protonation or hydrogen abstraction mechanisms involving the solvent. Cyclization efficiencies are much lower than is the case for previously-investigated 2-vinylbiphenyl systems. The 2-phenyldiphenylacetylenes have high fluorescence quantum yields and long singlet lifetimes when compared to diphenylacetylene. The 2-ethynylbiphenyls decay via a combination of fluorescence and intersystem crossing.