In the absence of a basal lamina, ameloblasts absorb enamel in a serumless and chemically defined organ culture system.

OBJECTIVES: Tooth organ development was examined in a serumless, chemically defined organ culture system to determine whether morphological and functional development was identical to that in in vivo and serum-supplemented organ cultures. METHODS: Mouse mandibular first molar tooth organs at 16 days of gestation were cultured for up to 28 days in a Tronwell culture system using a serum-supplemented or serumless, chemically defined medium. After culture, specimens were processed for assessing tooth development using ultrastructural, immunohistochemical, and mRNA expression analyses. RESULTS: In serum-supplemented conditions, inner enamel epithelial cells differentiated into secretory-stage ameloblasts, which formed enamel and reached the maturation stage after 14 and 21 days of culture, respectively. Ameloblasts deposited a basal lamina on immature enamel. Conversely, in serumless conditions, ameloblasts formed enamel on mineralized dentin after 21 days. Moreover, maturation-stage ameloblasts did not form basal lamina and directly absorbed mineralized enamel after 28 days of culture. RT-PCR analysis indicated that tooth organs, cultured in serumless conditions for 28 days, had significantly reduced expression levels of ODAM, amelotin, and laminin-322. CONCLUSIONS: These results indicate that several differences were detected compared to the development in serum-supplemented conditions, such as delayed enamel and dentin formation and the failure of maturation-stage ameloblasts to form basal laminae. Therefore, our results suggest that some factors might be required for the steady formation of mineralized dentin, enamel, and a basal lamina. Additionally, our results indicate that a basal lamina is necessary for enamel maturation.

Randomized phase III study of bevacizumab plus FOLFIRI and bevacizumab plus mFOLFOX6 as first-line treatment for patients with metastatic colorectal cancer (WJOG4407G).

BACKGROUND: FOLFIRI and FOLFOX have shown equivalent efficacy for metastatic colorectal cancer (mCRC), but their comparative effectiveness is unknown when combined with bevacizumab. PATIENTS AND METHODS: WJOG4407G was a randomized, open-label, phase III trial conducted in Japan. Patients with previously untreated mCRC were randomized 1:1 to receive either FOLFIRI plus bevacizumab (FOLFIRI + Bev) or mFOLFOX6 plus bevacizumab (mFOLFOX6 + Bev), stratified by institution, adjuvant chemotherapy, and liver-limited disease. The primary end point was non-inferiority of FOLFIRI + Bev to mFOLFOX6 + Bev in progression-free survival (PFS), with an expected hazard ratio (HR) of 0.9 and non-inferiority margin of 1.25 (power 0.85, one-sided α-error 0.025). The secondary end points were response rate (RR), overall survival (OS), safety, and quality of life (QoL) during 18 months. This trial is registered to the University Hospital Medical Information Network, number UMIN000001396. RESULTS: Among 402 patients enrolled from September 2008 to January 2012, 395 patients were eligible for efficacy analysis. The median PFS for FOLFIRI + Bev (n = 197) and mFOLFOX6 + Bev (n = 198) were 12.1 and 10.7 months, respectively [HR, 0.905; 95% confidence interval (CI) 0.723-1.133; P = 0.003 for non-inferiority]. The median OS for FOLFIRI + Bev and mFOLFOX6 + Bev were 31.4 and 30.1 months, respectively (HR, 0.990; 95% CI 0.785-1.249). The best overall RRs were 64% for FOLFIRI + Bev and 62% for mFOLFOX6 + Bev. The common grade 3 or higher adverse events were leukopenia (11% in FOLFIRI + Bev/5% in mFOLFOX6 + Bev), neutropenia (46%/35%), diarrhea (9%/5%), febrile neutropenia (5%/2%), peripheral neuropathy (0%/22%), and venous thromboembolism (6%/2%). The QoL assessed by FACT-C (TOI-PFC) and FACT/GOG-Ntx was favorable for FOLFIRI + Bev during 18 months. CONCLUSION: FOLFIRI plus bevacizumab was non-inferior for PFS, compared with mFOLFOX6 plus bevacizumab, as the first-line systemic treatment for mCRC. CLINICAL TRIALS NUMBER: UMIN000001396.

Effects of high molecular weight hyaluronan on the distribution and movement of proteoglycan around chondrocytes cultured in alginate beads.

OBJECTIVE: To evaluate the effects of high molecular weight hyaluronan (HA) on the distribution and movement of proteoglycan (PG) formed around rabbit chondrocytes cultured in alginate beads. DESIGN: Rooster comb-derived HA (MW 8x10(5) Da) was co-polymerized in alginate gel to study the direct effects of extrinsic HA on chondrocytes. PG metabolism of rabbit chondrocytes cultured in alginate beads was examined by measuring the incorporation of [(35)S]sulfate into glycosaminoglycan in two distinct regions, the cells with their cell-associated matrix (CM) and the further-removed matrix (FRM). Immunohistochemical analysis was performed using monoclonal antibodies against chondroitin sulfate and keratan sulfate. Autoradiography using degenerated cartilage tissue from the rabbit osteoarthritis (OA) model was performed to discover the effect of HA on the distribution of newly-synthesized PG in the cartilage tissue. RESULTS: The incorporation of [(35)S]sulfate into newly-synthesized PG in the cells with CM decreased with the addition of 0.125-1.0 mg/ml HA, while the incorporation in the FRM increased. These effects of HA on the distribution of newly-synthesized PG were the same either in chondrocytes with CM or chondrocytes without CM. Immunohistochemical analysis showed that staining of PG in the CM was decreased and staining in the FRM was increased in the HA treated group compared to the control group. Autoradiography using degenerated cartilage tissue from the rabbit OA model indicated that [(35)S]-labeled macromolecules showed a more diffuse distribution in the HA treated group compared with the control group. CONCLUSION: These results indicate that extrinsic HA could affect the movement of newly-synthesized PG from the CM to the FRM in both alginate beads and cartilage tissue.

Vav family proteins couple to diverse cell surface receptors.

Vav proteins are guanine nucleotide exchange factors for Rho family GTPases which activate pathways leading to actin cytoskeletal rearrangements and transcriptional alterations. Vav proteins contain several protein binding domains which can link cell surface receptors to downstream signaling proteins. Vav1 is expressed exclusively in hematopoietic cells and tyrosine phosphorylated in response to activation of multiple cell surface receptors. However, it is not known whether the recently identified isoforms Vav2 and Vav3, which are broadly expressed, can couple with similar classes of receptors, nor is it known whether all Vav isoforms possess identical functional activities. We expressed Vav1, Vav2, and Vav3 at equivalent levels to directly compare the responses of the Vav proteins to receptor activation. Although each Vav isoform was tyrosine phosphorylated upon activation of representative receptor tyrosine kinases, integrin, and lymphocyte antigen receptors, we found unique aspects of Vav protein coupling in each receptor pathway. Each Vav protein coprecipitated with activated epidermal growth factor and platelet-derived growth factor (PDGF) receptors, and multiple phosphorylated tyrosine residues on the PDGF receptor were able to mediate Vav2 tyrosine phosphorylation. Integrin-induced tyrosine phosphorylation of Vav proteins was not detected in nonhematopoietic cells unless the protein tyrosine kinase Syk was also expressed, suggesting that integrin activation of Vav proteins may be restricted to cell types that express particular tyrosine kinases. In addition, we found that Vav1, but not Vav2 or Vav3, can efficiently cooperate with T-cell receptor signaling to enhance NFAT-dependent transcription, while Vav1 and Vav3, but not Vav2, can enhance NFkappaB-dependent transcription. Thus, although each Vav isoform can respond to similar cell surface receptors, there are isoform-specific differences in their activation of downstream signaling pathways.

Dose estimations of fast neutrons from a nuclear reactor by micronuclear yields in onion seedlings.

Irradiations of onion seedlings with fission neutrons from bare, Pb-moderated, and Fe-moderated 252Cf sources induced micronuclei in the root-tip cells at similar rates. The rate per cGy averaged for the three sources, , was 19 times higher than rate induced by 60Co gamma-rays. When neutron doses, Dn, were estimated from frequencies of micronuclei induced in onion seedlings after exposure to neutron-gamma mixed radiation from a 1 W nuclear reactor, using the reciprocal of as conversion factor, resulting Dn values agreed within 10% with doses measured with paired ionizing chambers. This excellent agreement was achieved by the high sensitivity of the onion system to fast neutrons relative to gamma-rays and the high contribution of fast neutrons to the total dose of mixed radiation in the reactor's field.

[Clinical effects of chewing gum containing egg-white lysozyme and mace extract].

The purpose of this study was to evaluate the clinical effect of mace extract and egg-white lysozyme in two brands of chewing gum on gingival condition. Ever since mace extract containing dihydroguaiaretic acid was reported to inhibit the growth of Streptococcus mutans, plans were devised to include it in commercially available chewing gum. Before starting this study, two different types of experimental chewing gum containing mace extract or egg-white lysozyme were made up. A control was also prepared containing neither agent. The periodontal condition of 68 patients with gingivitis was determined based on PMA index (PMA), gingival index (GI), gingival bleeding index (GBI) and plaque scoring system (PSS) and randomly classified into three groups. Each group was instructed to use one or the other of the above type chewing gums after every meal. The results were as follows: 1. No clinical changes were observed in the control group during this study. 2. Gingival inflammation (PMA, GI, GBI) significantly improved as a result of using the experimental gums. 3. Plaque reduction was found only in the mece-extract gum group. 4. No clinical side effects were detected during this study.