The inherent heterogeneity of bone cells complicates the interpretation of microarray studies designed to identify genes highly associated with osteoblast differentiation. To overcome this problem, we have utilized Col1a1 promoter-green fluorescent protein transgenic mouse lines to isolate bone cells at distinct stages of osteoprogenitor maturation. Comparison of gene expression patterns from unsorted or isolated sorted bone cell populations at days 7 and 17 of calvarial cultures revealed an increased specificity regarding which genes are selectively expressed in a subset of bone cell types during differentiation. Furthermore, distinctly different patterns of gene expression associated with major signaling pathways (Igf1, Bmp, and Wnt) were observed at different levels of maturation. Some of our data differ from current models of osteoprogenitor cell differentiation and emphasize components of the pathways that were not revealed in studies based on a total cell population. Thus, applying methods to generate more homogeneous populations of cells at a defined level of cellular differentiation from a primary osteogenic culture is feasible and leads to a novel interpretation of the gene expression associated with increasing levels of osteoprogenitor maturation.

No abstract

A novel human organic transporter, OATP2, has been identified that transports taurocholic acid, the adrenal androgen dehydroepiandrosterone sulfate, and thyroid hormone, as well as the hydroxymethylglutaryl-CoA reductase inhibitor, pravastatin. OATP2 is expressed exclusively in liver in contrast to all other known transporter subtypes that are found in both hepatic and nonhepatic tissues. OATP2 is considerably diverged from other family members, sharing only 42% sequence identity with the four other subtypes. Furthermore, unlike other subtypes, OATP2 did not transport digoxin or aldosterone. The rat isoform oatp1 was also shown to transport pravastatin, whereas other members of the OATP family, i.e. rat oatp2, human OATP, and the prostaglandin transporter, did not. Cis-inhibition studies indicate that both OATP2 and roatp1 also transport other statins including lovastatin, simvastatin, and atorvastatin. In summary, OATP2 is a novel organic anion transport protein that has overlapping but not identical substrate specificities with each of the other subtypes and, with its liver-specific expression, represents a functionally distinct OATP isoform. Furthermore, the identification of oatp1 and OATP2 as pravastatin transporters suggests that they are responsible for the hepatic uptake of this liver-specific hydroxymethylglutaryl-CoA reductase inhibitor in rat and man.

Clin. Invest. 1993. 91:2539-2545

The effect of insulin-like growth factor (IGF) on tumor necrosis factor (TNF)-induced cell killing was determined for mouse BALB/c3T3 fibroblasts in vitro. Cells maintained in 0.5% fetal bovine serum (FBS) were killed by TNF within 6 h in a concentration-dependent manner, an effect that was prevented by IGF-I. TNF-induced cytotoxicity of 3T3 cells that overexpress the human IGF-I receptor (p6 cells) was prevented by IGF-I alone in the absence of serum. TNF-induced cell death was associated with the morphologic features of apoptosis and the release of low-molecular-weight DNA, both of which were prevented by IGF-I. Neither epidermal growth factor (EGF) nor platelet-derived growth factor (PDGF) protected p6 cells from TNF-induced apoptosis. The specific protective action of the IGF-I receptor was demonstrated further by the marked sensitivity to TNF of embryo fibroblasts derived from mice with targeted disruption of the IGF-I receptor (R-cells) but not of fibroblasts derived from wild-type littermates or R-cells transfected with the cDNA for the human IGF-I receptor. Cycloheximide or actinomycin D markedly reduced the protection offered by IGF-I. IGF-I protection of BALB/c3T3 cells persisted for up to 5 days in the presence of PDGF and EGF, whereas IGF-I lost its effectiveness after 2 days in the absence of growth factors. IGF-I did not prevent TNF-induced release of arachidonic acid. The results demonstrate a specific role for the IGF-I receptor in the protection against TNF cytotoxicity. This action of the IGF-I receptor is mediated by protective cytosolic proteins that exhibit a high rate of turnover and whose levels are regulated principally by factors within serum other than IGF-I.

Our objective was to compare the results of reconstruction of isolated chronic posterior cruciate ligament (PCL) injury using a four-strand hamstring graft (4SHG) and a LARS artificial ligament. Thirty-six patients were divided into a 4SHG group (n=15) and a LARS group (n=21). The minimum follow-up time was two years. The outcome measures used were KT-1000 measurements, the International Knee Documentation Committee (IKDC) scoring system, Lysholm knee scoring scale and Tegner activity rating. Both groups improved significantly between the preoperative and postoperative assessment in terms of the knee laxity and functional examination (P<0.01). Meanwhile, knee stability was significantly improved in the LARS group when compared with the 4SHG group (P<0.05); this was also the case for the Lysholm, Tegner and IKDC scores (P<0.05). Our study indicates that using a LARS ligament for PCL reconstruction was clinically more useful than using a 4SHG in the treatment of the PCL-deficient knee.

In patients undergoing THA, LIA may reduce postoperative systemic opioid use and offer better pain control and earlier rehabilitation, without observable risks.

To assess the efficacy of postoperative pain management and the concentration change of PGE-2 and IL-6 of joint fluid with parecoxib after postoperative total knee arthroplasty. In the study, 100 patients experiencing primary TKA were randomly divided into study group, receiving parecoxib sodium (40 mg) intravenously (IV) at the completion of surgery and once every 12 h for totally 6 times postoperatively, and placebo group, receiving normal saline 2 mL IV at the same time points. Efficacy was assessed by total amount of morphine consumed, pain intensity, range of motion (ROM), the concentration change of PGE-2 and IL-6 of joint fluid, and postoperative nausea and vomiting (PONV) postoperatively. Patients in study group consumed significantly less morphine, experienced significant less pain scores, and obtained significantly more ROM (P < 0.01) compared with that in placebo group during 3 days postoperatively. The concentration of PGE-2 and IL-6 of joint fluid in study group are significantly lower than that in placebo group (P < 0.01) during 24 h postoperatively. The overall incidence of PONV was low and was not significantly different between the two groups. The present study demonstrated that the perioperative administration of parecoxib after primary TKA resulted in significantly improved postoperative analgesic management as defined by reduction in opioid requirement, lower pain scores and ROM, and significantly lowered local inflammation factors PGE2 and IL-6.