Delivery of Ad-BMP-2 or Ad-BMP-6 via direct injection supported cartilage and subchondral bone regeneration but was insufficient to provide long-term quality osteochondral repair.

The functions of parathyroid hormone-related protein (PTHrP) on morphogenesis, cell proliferation, apoptosis, and calcium homeostasis have been attributed to its N terminus. Evidence suggests that many of these effects are not mediated by the N terminus but by the midregion, a nuclear localization sequence (NLS), and C terminus of the protein. A knock-in mouse lacking the midregion, NLS, and C terminus of PTHrP (Pthrp(Delta/Delta)) was developed. Pthrp(Delta/Delta) mice had craniofacial dysplasia, chondrodysplasia, and kyphosis, with most mice dying by d 5 of age. In bone, there were fewer chondrocytes and osteoblasts per area, bone mass was decreased, and the marrow was less cellular, with erythroid hypoplasia. Cellular proliferation was impaired, and apoptosis was increased. Runx2, Ocn, Sox9, Crtl1, beta-catenin, Runx1, ephrin B2, cyclin D1, and Gata1 were underexpressed while P16/Ink4a, P21, GSK-3beta, Il-6, Ffg3, and Ihh were overexpressed. Mammary gland development was aberrant, and energy metabolism was deregulated. These results establish that the midregion, NLS, and C terminus of PTHrP are crucial for the commitment of osteogenic and hematopoietic precursors to their lineages, and for survival, and many of the effects of PTHrP on development are not mediated by its N terminus. The down-regulation of Runx1, Runx2, and Sox9 indicates that PTHrP is a modulator of transcriptional activation during stem cell commitment.

Animals sample sensory stimuli for longer periods when they must perform difficult discrimination tasks, implying that the brain's ability to represent stimuli improves as a function of time. Though it is true in other senses, few studies have examined whether increasing sampling time improves olfactory discrimination. In the experiments reported here, we controlled odor sampling time with the goal of testing whether odor concentration affected a honeybee's ability to learn, recognize, and discriminate odors. We observed that increasing sampling time during conditioning and testing improved a honeybee's ability to learn, recognize, and differentiate low concentration (0.0002M) odors. For intermediate (0.02M) concentration odors, both acquisition and recognition improved when stimulus duration was longer, but discrimination was unaffected. Having longer to sample a high concentration (2.0M) stimulus also improved acquisition, but it did not affect the ability to recognize or differentiate odors. Differences in the time taken to respond to the conditioned and novel odors during the test period depended upon the difficulty of the discrimination task. Our results suggest that the sensory coding of molecular identity takes longer for low concentration odors.

There was no significant escape of bevacizumab and ranibizumab from the vitreous cavity after intravitreal injection. After correction for radioactive decay, both agents remained detectable until 28 and 21 days, respectively, with retention properties that validated those methods reported in previous studies.

The cranial neural crest (CNC) undergoes complex molecular and morphological changes during embryogenesis in order to form the vertebrate skull, and nearly three quarters of all birth defects result from defects in craniofacial development. The molecular events leading to CNC differentiation have been extensively studied; however, the role of the cAMP-dependent protein kinase [protein kinase A (PKA)] during craniofacial development has only been described in palate formation. Here, we provide evidence that strict PKA regulation in postmigratory CNC cells is essential during craniofacial bone development. Selective inactivation of Prkar1a, a regulatory subunit of the PKA holoenzyme, in the CNC results in perinatal lethality caused by dysmorphic craniofacial development and subsequent asphyxiation. Additionally, aberrant differentiation of CNC mesenchymal cells results in anomalous intramembranous ossification characterized by formation of cartilaginous islands in some areas and osteolysis of bony trabeculae with fibrous connective tissue stabilization in others. Genetic interaction studies revealed that genetic reduction of the PKA catalytic subunit C(alpha) was able to rescue the phenotype, whereas reduction in Cbeta had no effect. Overall, these observations provide evidence of the essential role of proper regulation of PKA during the ossification of the bones of the skull. This knowledge may have implications for the understanding and treatment of craniofacial birth defects.

The tumor-associated glycoprotein-72 (TAG-72) antigen is highly overexpressed in various human adenocarcinomas and anti-TAG-72 monoclonal antibodies, and fragments are therefore useful as pharmaceutical targeting vectors. In this study, we investigated the effects of site-specific PEGylation with MW 2–4 kDa discrete, branched PEGylation reagents on mCC49 Fab′ (MW 50 kDa) via in vitro TAG72 binding, and in vivo blood clearance kinetics, biodistribution, and mouse tumor microPET/CT imaging. mCC49Fab′ (Fab′-NEM) was conjugated at a hinge region cysteine with maleimide-dPEG12-(dPEG24COOH)3 acid (Mal-dPEG-A), maleimide-dPEG12-(dPEG12COOH)3 acid (Mal-dPEG-B), or maleimide-dPEG12-(m-dPEG24)3 (Mal-dPEG-C), and then radiolabeled with iodine-124 (124I) in vitro radioligand binding assays and in vivo studies used TAG-72 expressing LS174T human colon carcinoma cells and xenograft mouse tumors. Conjugation of mCC49Fab′ with Mal-dPEG-A (Fab′-A) reduced the binding affinity of the non PEGylated Fab′ by 30%; however, in vivo, Fab′-A significantly lengthened the blood retention vs Fab′-NEM (47.5 vs 28.1%/ID at 1 h, 25.1 vs 8.4%/ID at 5 h, p < 0.01), showed excellent tumor to background, better microPET/CT images due to higher tumor accumulation, and increased tumor concentration in excised tissues at 72 h by 130% (5.09 ± 0.83 vs 3.83 ± 1.50%ID/g, p < 0.05). Despite the strong similarity of the three PEGylation reagents, PEGylation with Mal-dPEG-B or -C reduced the in vitro binding affinity of Fab′-NEM by 70%, blood retention, microPET/CT imaging tumor signal intensity, and residual 72 h tumor concentration by 49% (3.83 ± 1.50 vs 1.97 ± 0.29%ID/g, p < 0.05) and 63% (3.83 ± 1.50 vs 1.42 ± 0.35%ID/g, p < 0.05), respectively. We conclude that remarkably subtle changes in the structure of the PEGylation reagent can create significantly altered biologic behavior. Further study is warranted of conjugates of the triple branched, negatively charged Mal-dPEG-A.

Background18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) is widely used in diagnostic cancer imaging. However, the use of 18F-FDG in PET-based imaging is limited by its specificity and sensitivity. In contrast, anti-TAG (tumor associated glycoprotein)-72 monoclonal antibodies are highly specific for binding to a variety of adenocarcinomas, including colorectal cancer. The aim of this preliminary study was to evaluate a complimentary determining region (CDR)-grafted humanized CH2-domain-deleted anti-TAG-72 monoclonal antibody (HuCC49deltaCH2), radiolabeled with iodine-124 (124I), as an antigen-directed and cancer-specific targeting agent for PET-based imaging.MethodsHuCC49deltaCH2 was radiolabeled with 124I. Subcutaneous tumor implants of LS174T colon adenocarcinoma cells, which express TAG-72 antigen, were grown on athymic Nu/Nu nude mice as the xenograft model. Intravascular (i.v.) and intraperitoneal (i.p.) administration of 124I-HuCC49deltaCH2 was then evaluated in this xenograft mouse model at various time points from approximately 1 hour to 24 hours after injection using microPET imaging. This was compared to i.v. injection of 18F-FDG in the same xenograft mouse model using microPET imaging at 50 minutes after injection.ResultsAt approximately 1 hour after i.v. injection, 124I-HuCC49deltaCH2 was distributed within the systemic circulation, while at approximately 1 hour after i.p. injection, 124I-HuCC49deltaCH2 was distributed within the peritoneal cavity. At time points from 18 hours to 24 hours after i.v. and i.p. injection, 124I-HuCC49deltaCH2 demonstrated a significantly increased level of specific localization to LS174T tumor implants (p = 0.001) when compared to the 1 hour images. In contrast, approximately 50 minutes after i.v. injection, 18F-FDG failed to demonstrate any increased level of specific localization to a LS174T tumor implant, but showed the propensity toward more nonspecific uptake within the heart, Harderian glands of the bony orbits of the eyes, brown fat of the posterior neck, kidneys, and bladder.ConclusionsOn microPET imaging, 124I-HuCC49deltaCH2 demonstrates an increased level of specific localization to tumor implants of LS174T colon adenocarcinoma cells in the xenograft mouse model on delayed imaging, while 18F-FDG failed to demonstrate this. The antigen-directed and cancer-specific 124I-radiolabled anti-TAG-72 monoclonal antibody conjugate, 124I-HuCC49deltaCH2, holds future potential for use in human clinical trials for preoperative, intraoperative, and postoperative PET-based imaging strategies, including fused-modality PET-based imaging platforms.

Oral squamous cell carcinoma is common in cats and humans and invades oral bone. We hypothesized that the cyclooxygenase-2 inhibitor, meloxicam, with the bisphosphonate, zoledronic acid (ZOL), would inhibit tumor growth, osteolysis and invasion in feline oral squamous cell carcinoma (OSCC) xenografts in mice. Human and feline OSCC cell lines expressed cyclooxygenase (COX)-1 and 2 and the SCCF2 cells had increased COX-2 mRNA expression with bone conditioned medium. Luciferase-expressing feline SCCF2Luc cells were injected beneath the perimaxillary gingiva and mice were treated with 0.1 mg/kg ZOL twice weekly, 0.3 mg/kg meloxicam daily, combined ZOL and meloxicam, or vehicle. ZOL inhibited osteoclastic bone resorption at the tumor-bone interface. Meloxicam was more effective than ZOL at reducing xenograft growth but did not affect osteoclastic bone resorption. Although a synergistic effect of combined ZOL and meloxicam was not observed, combination therapy was well tolerated and may be useful in the clinical management of bone-invasive feline OSCC.