Biological Effects of Anti-RANKL Antibody and Zoledronic Acid on Growth and Tooth Eruption in Growing Mice.

The anti-bone resorptive drugs denosumab, an anti-human-RANKL antibody, and zoledronic acid (ZOL), a nitrogen-containing bisphosphonate, have recently been applied for treatment of pediatric patients with bone diseases, though details regarding their effects in growing children have yet to be fully elucidated. In the present study, we administered these anti-resorptive drugs to mice from the age of 1 week and continued once-weekly injections for a total of 7 times. Mice that received the anti-RANKL antibody displayed normal growth and tooth eruption, though osteopetrotic bone volume gain in long and alveolar bones was noted, while there were nearly no osteoclasts and a normal of number osteoblasts observed. In contrast, ZOL significantly delayed body growth, tooth root formation, and tooth eruption, with increased osteoclast and decreased osteoblast numbers. These findings suggest regulation of tooth eruption via osteoblast differentiation by some types of anti-resorptive drugs.

Exceptional contact elasticity of human enamel in nanoindentation test.

OBJECTIVE: Tooth enamel has unsurpassed hardness and stiffness among mammalian tissue structures. Such stiff materials are usually brittle, yet mature enamel can survive for a lifetime. Understanding the nanoscale origin of enamel durability is important for developing advanced load-bearing biomaterials. Here, nanoscale exceptional contact elasticity of the human tooth enamel, based on nanoindentation tests, is reported. METHODS: Spherical indenter tips with radii of 243 and 1041nm were used to determine stress-strain curves of enamel. Force-displacement curves were recorded using quasi-static loading strain rates of 0.031, 0.041, and 0.061s-1. The storage moduli from a superimposed signal amplitude (dynamic strain at 220Hz) embedded during primary quasi-static loading and from quasi-static elastic theory were simultaneously measured. Modulus mapping was considered to be an extremely low quasi-static loading strain rate indentation test. RESULTS: The elastic limits were 7-9GPa and 5-6GPa for the small and large indenters, respectively. The elastic-plastic transition point and elastic modulus value increased with substantially increased quasi-static loading strain rate. The results suggested that the increase of the elastic limit during high-loading strain was associated with exceptional contact elasticity at the nanoscale of the enamel structure and the consequent extension of the contact area (i.e., a temporary pile-up response, dependent on the enamel nanocrystals and protein glue). SIGNIFICANCE: Structural modification at this scale effectively prevents the initiation of cracking from localized strain, thus reinforcing the bulk structure. These results may provide valuable insight for conceptualizing bio-inspired nanocomposites.

Proteome analysis of gelatin-bound urinary proteins from patients with bladder cancers.

OBJECTIVES: Proteome analysis with protein separation by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and mass spectrometric measurement is utilized for comprehensive identification of proteins in various biological samples. However, this technique has not been widely applied for the analysis of body fluid for clinical assessments, because large amounts of proteins in fluid such as albumin and globulin hinder the detection of small amounts of proteins with high clinical values. The aim of the present study is to develop a method of proteomic analysis for urine of patients with bladder cancers. MATERIALS AND METHODS: Urine samples collected from 40 patients with bladder cancers, 32 healthy volunteers, and 7 old volunteers with benign prostate hypertrophy were treated with gelatin-beads as a group-specific affinity carrier. The gelatin-bound proteins were subjected to the proteome analysis. RESULTS: Various amounts of matrix metalloproteinase-2 (MMP-2), -9 (MMP-9), fibronectin (FN), and their fragments were identified on 2-D PAGE gels from cancer-bearing patients, but not from normal individuals. Importantly, not only total amounts of these proteins, but also patterns of their distributions on the gels were well matched with the extent of invasion diagnosed with histopathological examinations. Thus, the score including such qualitative patterning of these proteins predicts pathological stages of the cancer. CONCLUSION: The proteomic analysis with gelatin-affinity purification of urine samples is useful not only for the diagnosis of bladder cancers, but also for estimating the extent of tumor invasion.

Characterization of Salmonella pathogenicity island 1 type III secretion-dependent hemolytic activity in Salmonella enterica serovar Typhimurium.

A number of bacteria that are pathogenic for animals and plants possess a type III secretion system (TTSS) to translocate virulence-associated proteins into host cells. In several bacteria, it has been reported that the TTSS is correlated with an ability to cause contact-dependent hemolysis in vitro. Here, we showed that the Salmonella enterica serovar Typhimurium strain SL1344 exhibited Salmonella pathogenicity island 1 type III secretion-dependent, contact-mediated, hemolytic activity. Mutations with a single deletion in genes encoding putative pore-forming proteins, SipB and SipC, secreted by the TTSS abolished hemolytic activity. In addition, the osmoprotection studies revealed that molecules larger than PEG2000 conferred significant protection against lysis induced by Salmonella. These results indicate that the hemolysis generated by Salmonella is due to the formation of pores within the erythrocyte membrane.