The effect of postsurgical naproxen and a bioabsorbable membrane on osseous healing in intrabony defects.

BACKGROUND: Previous reports in the literature have shown that non-steroidal anti-inflammatory drugs (NSAID) may affect osseous tissues by either stimulating or inhibiting bone formation. This effect can be drug specific and different NSAIDs may produce opposite results. There are also reports showing that NSAIDs inhibit bone loss due to inflammatory disease process. The purpose of this randomized, controlled, blinded, clinical investigation was to determine the effect of a one week course of postsurgical naproxen on the osseous healing in intrabony defects. METHODS: Twenty-four vertical osseous defects in 24 patients were treated with either a bioabsorbable membrane plus twice daily postsurgical naproxen 500 mg for one week (test or GPN group) or with a polylactide bioabsorbable membrane alone (control or GA group). Twelve patients were included in each group. Treatment was performed on either 2- or 3-wall or combination defects. All measurements were taken from a stent by a calibrated, blinded examiner and open measurements were repeated at the 9-month second stage surgery. Power analysis to determine superiority of naproxen treatment showed that a 12 per group sample size would yield 87% power to detect a 2.0 mm difference and 64% power to detect a 1.5 mm difference. RESULTS: Open defect measurements from baseline to 9 months showed a statistically significant (P < 0.05) mean defect fill of 1.96 +/- 1.27 mm and 2.04 +/- 1.71 for the GPN and GA groups, respectively. This corresponded to a mean defect fill of 42% and a mean defect resolution of approximately 75% for both groups. The differences between GPN and GA groups were not statistically significant (P > 0.05). Defect fill of > or = 50% was seen in 6 defects (50%) in the GPN group and in 5 defects (42%) in the GA group. CONCLUSIONS: The administration of postsurgical naproxen failed to produce osseous healing that was statistically superior to that obtained with polylactide bioabsorbable membranes alone.     

Effects of antidiuretic hormone on urinary acidification and on tubular handling of bicarbonate in the rat.

Paired micropuncture experiments were carried out in plasma-replete volume-expanded rats to examine the acute effects of 1-desamino-8-D-arginine vasopressin (dDAVP) on urinary acidification and tubular handling of bicarbonate and chloride. No effect was detected on the fractional absorption of water, total CO2, and chloride at end-proximal and early distal sites of superficial nephrons in intact animals; dDAVP, however, inhibited the fractional absorption of total CO2 in Henle's loop while stimulating that of chloride in thyroparathyroidectomized (TPTX) somatostatin-infused rats. In the distal tubule accessible to micropuncture, net total CO2 secretion was observed during hypotonic volume expansion, which reversed to net total CO2 absorption during dDAVP infusion in intact Wistar rats. Marked stimulation of urinary acidification occurred in all animals as attested by a fall in urine pH and bicarbonate excretion. Net acid excretion almost doubled in intact rats. We conclude that (a) antidiuretic hormone (ADH) inhibits fractional bicarbonate absorption in the thick ascending limb while stimulating that of chloride at least in TPTX somatostatin-infused rats, and (b) ADH stimulates proton secretion (or inhibits bicarbonate secretion) in the distal tubule and cortical collecting ducts, which leads to enhanced urinary acidification.     

The tissue-engineered auricle: past, present, and future

The reconstruction, repair, and regeneration of the external auricular framework continue to be one of the greatest challenges in the field of tissue engineering. To replace like with like, we should emulate the native structure and composition of auricular cartilage by combining a suitable chondrogenic cell source with an appropriate scaffold under optimal in vitro and in vivo conditions. Due to the fact that a suitable and reliable substitute for auricular cartilage has yet to be engineered, hand-carved autologous costal cartilage grafts and ear-shaped porous polyethylene implants are the current treatment modalities for auricular reconstruction. However, over the last decade, significant advances have been made in the field of regenerative medicine and tissue engineering. A variety of scaffolds and innovative approaches have been investigated as alternatives to using autologous carved costal cartilage or porous polyethylene implants. A review of recent developments and the current state of the art and science is presented, focusing on scaffolds, cell sources, seeding densities, and mechanical characteristics of tissue-engineered auricular cartilage.     

Chondrogenic Priming Adipose-Mesenchymal Stem Cells for Cartilage Tissue Regeneration

Purpose  

Chondrocytes lose their ability to produce cartilaginous matrix during multiplication in culture through repeated passages, resulting in inferior tissue phenotype. To overcome the limited amount of primary chondrocytes, we aimed to determine the optimal culture condition for in vitro/in vivo cartilage regeneration using human adipose-derived mesenchymal stem cells (AMSCs).