Bovine and equine peritubular and intertubular dentin

Dentin contains 1-2μm diameter tubules extending from the pulp cavity to near the junction with enamel. Peritubular dentin (PTD) borders the tubule lumens and is surrounded by intertubular dentin (ITD). Differences in PTD and ITD composition and microstructure remain poorly understood. Here, a (∼200nm)(2), 10.1keV synchrotron X-ray beam maps X-ray fluorescence and X-ray diffraction simultaneously around tubules in 15-30μm thick bovine and equine specimens. Increased Ca fluorescence surrounding tubule lumens confirms that PTD is present, and the relative intensities in PTD and ITD correspond to carbonated apatite (cAp) volume fraction of ∼0.8 in PTD vs. 0.65 assumed for ITD. In the PTD near the lumen edges, Zn intensity is strongly peaked, corresponding to a Zn content of ∼0.9mgg(-1) for an assumed concentration of ∼0.4mgg(-1) for ITD. In the equine specimen, the Zn K-edge position indicates that Zn(2+) is present, similar to bovine dentin (Deymier-Black et al., 2013), and the above edge structure is consistent with spectra from macromolecules related to biomineralization. Transmission X-ray diffraction shows only cAp, and the 00.2 diffraction peak (Miller-Bravais indices) width is constant from ITD to the lumen edge. The cAp 00.2 average preferred orientation is axisymmetric (about the tubule axis) in both bovine and equine dentin, and the axisymmetric preferred orientation continues from ITD through the PTD to the tubule lumen. These data indicate that cAp structure does not vary from PTD to ITD.

Effect of short chain fatty acids on the expression of free fatty acid receptor 2 (Ffar2), Ffar3 and early-stage adipogenesis

Adipose tissue has a major influence on insulin sensitivity. Stimulation of free fatty acid receptor 2 (FFAR2) has been proposed to influence adipocyte differentiation. We hypothesised that exposing preadipocytes to short chain fatty acids would induce earlier expression of nuclear receptors that co-ordinate adipogenesis, triglyceride accumulation and leptin secretion. 3T3-L1 preadipocytes were differentiated in the presence of 1 μM acetate, 0.1-10 μM propionate or vehicle control. In experiment 1, expression of Ffar2 and nuclear receptor mRNA was measured by quantitative PCR over 48 h following onset of differentiation. In experiment 2, extracellular leptin concentration and intracellular triglyceride content were measured at days 0, 2, 4, 6, 8 and 10 following the onset of differentiation. Control cells exhibited similar temporal dynamics of gene expression, triglyceride accumulation and leptin secretion as reported previously. We were unable to detect expression of Ffar3 mRNA at any stage of differentiation. Consistent with a lack of Ffar2 expression in the first 24 h of differentiation, acetate and propionate had no significant effect on nuclear receptor expression. Furthermore, acetate or propionate treatment did not alter leptin concentration or triglyceride content. In conclusion, we observed no significant effect of propionate or acetate on adipogenesis in 3T3-L1 cells using validated quantitative techniques.

dsRNA uptake and persistence account for tissue-dependent susceptibility to RNA interference in the migratory locust, Locusta migratoria

RNA interference (RNAi) by introducing double-stranded RNA (dsRNA) is a powerful approach to the analysis of gene function in insects; however, RNAi responses vary dramatically in different insect species and tissues, and the underlying mechanisms remain poorly understood. The migratory locust, a destructive insect pest and a hemimetabolic insect with panoistic ovaries, is considered to be a highly susceptible species to RNAi via dsRNA injection, but its ovary appears to be completely insensitive. In the present study, we showed that dsRNA persisted only briefly in locust haemolymph. The ovariole sheath was permeable to dsRNA, but injected dsRNA was not present in the follicle cells and oocytes. The lack of dsRNA uptake into the follicle cells and oocytes is likely to be the primary factor that contributes to the ineffective RNAi response in locust ovaries. These observations provide insights into tissue-dependent variability of RNAi and help in achieving successful gene silencing in insensitive tissues.

Crystallographic texture and elemental composition mapped in bovine root dentin at the 200 nm level

The relationship between the mineralization of peritubular dentin (PTD) and intertubular dentin (ITD) is not well understood. Tubules are quite small, diameter ∼2 µm, and this makes the near-tubule region of dentin difficult to study. Here, advanced characterization techniques are applied in a novel way to examine what organic or nanostructural signatures may indicate the end of ITD or the beginning of PTD mineralization. X-ray fluorescence intensity (Ca, P, and Zn) and X-ray diffraction patterns from carbonated apatite (cAp) were mapped around dentintubules at resolutions ten times smaller than the feature size (200 nm pixels), representing a 36% increase in resolution over earlier work. In the near tubule volumes of near-pulp, root dentin, Zn intensity was higher than in ITD remote from the tubules. This increase in Zn(2+), as determined by X-ray absorption near edge structure analysis, may indicate the presence of metalloenzymes or transcription factors important to ITD or PTD mineralization. The profiles of the cAp 00.2 X-ray diffraction rings were fitted with a pseudo-Voigt function, and the spatial and azimuthal distribution of these rings' integrated intensities indicated that the cAp platelets were arranged with their c-axes aligned tangential to the edge of the tubule lumen. This texture was continuous throughout the dentin indicating a lack of structural difference between in the Zn rich near-tubular region and the remote ITD.

Modified Sauvé-Kapandji procedure for restoration of forearm rotation in devascularized hands

INTRODUCTION

The purpose of this study is to evaluate the clinical outcomes in patients with forearm rotation limitation after successful wrist-level revascularization who underwent a modified Sauvé-Kapandji (S-K) procedure.

METHODS

This was a retrospective review of the clinical records of nine patients (three women, six men) after successful wrist-level revascularization who underwent late restoration of forearm rotation. All patients were evaluated using a Mayo Modified Wrist Score. The mean patient age was 35 (range 19-45) years. Mean time to reconstruction was 2.5 (range 0.5-4) years.

RESULTS

Mean postoperative pronation was 74°; mean postoperative supination was 80°. Overall results were excellent/good in seven patients, fair in one, and poor in one. No bone bridge was formed between the pseudarthrosis in any patient. Two patients had neurapraxia. Moderate pain and snapping occurred in one patient during movement at the ulnar amputation site.

CONCLUSION

This modification of the S-K procedure can restore rotation of the forearm after hand revascularization; as such, it provides an alternative salvage procedure.

Abstract P4-12-14: Metal chelating polymer-conjugated trastuzumab labeled to high specific activity with indium-111 is cytotoxic to trastuzumab-sensitive and resistant breast cancer cells through the emission of auger electrons

Purpose: Auger electrons are very low energy electrons emitted by Indium-111(111In) that cause lethal DNA damage when emitted in close to the cell nucleus. Our laboratory reported previously that trastuzumab modified with nuclear localizing sequence (NLS) peptides and labeled with 111In(111In-NLS-DTPA-trastuzumab) was internalized and transported to the nucleus of HER2-overexpressing breast cancer (BC) cells, reducing their clonogenic survival (CS) to ≤10%. However, a limitation was that at the specific activity (SA) achieved (0.24 MBq/μg) for 111In-DTPA-trastuzumab without or with NLS, only 1 in 50 molecules was radiolabeled. This reduced the potency for cells with low or intermediate HER2 density. Our purpose was to dramatically increase the SA of 111In-labeled trastuzumab by conjugation to a metal chelating polymer (MCP) that displays multiple DTPA chelators for 111In and compare its potency to 111In-NLS-trastuzumab on BC cells with a wide range of HER2 density including cells resistant to trastuzumab.

Methods: An MCP with a polyglutamide backbone, 29 DTPA groups, and a hydrazide reactive end-group was site-specifically linked to periodate-oxidized carbohydrates on the Fc domain of trastuzumab. HER2 immunoreactivity, internalization and nuclear importation were evaluated by cell binding and fractionation studies using HER2-overexpressing SK-Br-3 human BC cells. The SA achievable was assessed by radiolabeling 1, 5, 50 and 100 μg of the immunoconjugates with 9.25 MBq of 111In. The effect of high SA (5.5 MBq/μg) 111In-MCP-trastuzumab to on the CS of human BC cells with a wide range of HER2 density (5×105-1.3×106 HER2 receptors/cell) that were sensitive or resistant to trastuzumab was compared to low SA (0.37 MBq/μg) 111In-labeled trastuzumab conjugates. Studies are also in progress to assess DNA double-strand breaks caused by the Auger electrons emitted by 111In using the γH2AX assay.

Results: MCP-trastuzumab bound specifically to HER2 with high affinity (KD = 10.7±1.5nM) and was internalized and imported into the nucleus of HER2-positive BC cells. The smallest mass that could be labeled (labeling efficiency>80%) with 111In for MCP-trastuzumab was 1 μg (SA = 8.9 MBq/μg) compared to 50 μg for DTPA-trastuzumab (SA = 0.08 MBq/μg). High SA 111In-MCP-trastuzumab reduced the CS of SK-Br-3 cells with high HER2 density to 1.8±1.3% and the CS of TrR1 trastuzumab-resistant BC cells with intermediate HER2 density to 17.1±1.6%. These represent a 4-5 and 5-6 fold greater potency compared to low SA 111In-trastuzumab conjugates on cells with high or intermediate HER2 expression, respectively.

Conclusion: 111In-MCP-trastuzumab was labeled to 37-fold higher SA than 111In-DTPA-trastuzumab. High SA increased its cytotoxicity potency for HER2-positive BC cells that were sensitive or resistant to trastuzumab. Auger electron radioimmunotherapy is a promising strategy for HER2-positive BC which may extend to trastuzumab-resistant tumours. Supported by a grant from the Canadian Breast Cancer Research Alliance with funds from the Canadian Cancer Society.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-12-14.

Abstract P4-15-04: Synthesis and characterization of EGFR antibody-mediated tumor targeted “gold nanobombs” for treatment of locally advanced breast cancer

Purpose: Epidermal growth factor receptor (EGFR) represents an important target for treatment of locally advanced breast cancer (LABC), since about 30% of patients with LABC have triple negative breast tumor, and these tumors are often EGFR-positive. Our aim was to synthesize and characterize a novel form of “gold nanobomb” (GNB) for localized targeted radioimmunotherapy of LABC. GNB uses gold nanoparticles (AuNPs) as a carrier to conjugate both EGFR targeting monoclonal antibody (panitumumab) and the β-particle emitting radionuclide 177Lu. Ultimately, these GNB would be administered locally in LABC for tumor treatment while minimizing normal tissue exposure.

Methods: The basic idea for construction of this new-targeted agent is to use different length of poly(ethylene glycol) (PEG) spacers to conjugate antibody and DOTA metal chelators for 177Lu. First, OPSS-PEG-NH2 was used to synthesize OPSS-PEG-DOTA for complexing 177Lu and OPSS-PEG-SVA was used to link antibody. Then these PEG spacers were linked to 30 nm AuNPs to form “GNB”. OPSS-PEG-antibody was analyzed by SDS-PAGE and trinitrobenzenesulfonic acid (TNBSA) assay to determine the degree of amine substitution after PEGylation. A radiometric assay was used to determine the number of PEGylated antibody and DOTA-PEG-OPSS per AuNPs. Specificity of GNB for EGFR and internalization into MBA-MD-468 (1×106 EGFR/cell), MBA-MD-231 (1×105 EGFR/cell) and MCF-7 (1×104 EGFR/cell) was confirmed by confocal and darkfield fluorescence microscopy. Binding assay and cell fractionation study were used to determine the binding affinity to EGFR and the total amount of GNB internalized.

Results: Reacting panitumumab with increasing ratios of PEG resulted in an increase in molecular weight from 147 to 250 kDa. This result was in accordance with TNBSA assay where increasing ratio of PEG was associated with increasing lysine substitution (1.4 to 50.9 PEGylated lysine per antibody). PEGylation of 1.4 ± 1.7 lysine per antibody resulted in retention of immunoreactivity and when the immunoconjugates were linked to AuNPs, 8.09 ± 0.38 antibodies were attached to one AuNP. The total number of OPSS-PEG-DOTA per AuNP was estimated to be 812 ± 53. The total size of GNB was 67.3 ± 0.6 nm and there was no particle precipitation or aggregation after incubation in PBS. Competitive binding assay revealed that GNB was targeted strongly to EGFR (Kd antibody: 2.7 ± 0.3 nM; Kd GNB: 5.0 ± 4.9 nM) and darkfield microscopy showed that low PEG to antibody ratio increased the targeting efficiency when compared to high PEG to antibody ratio. Confocal microscopy revealed specific GNB uptake in MDA-MB-468 cells and cell fractionation study demonstrated receptor-mediated internalization of GNB, where the total amount of GNB internalized was about 3.1 and 22.2 fold higher in MDA-MB-468 cells than in MDA-MB-231 or MCF-7 cells.

Conclusion: This GNB is very effective in targeting and in internalizing into EGFR, thus the GNB labeled with 177Lu emitting β-particles may be a promising new localized treatment for LABC. We plan to now examine the cytotoxicity of GNB both in vitro and in vivo will be explored for treatment of EGFR positive tumors. Supported by a grant from the Canadian Breast Cancer Foundation.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-15-04.

Origin of anomalous magnetite properties in crystallographic matched heterostructures: Fe3O4(111)/MgAl2O4(111)

Magnetite films grown on crystallographically matched substrates such as MgAl2O4 are not expected to show anomalous properties such as negative magnetoresistance and high saturation fields. By atomic resolution imaging using scanning transmission electron microscopy we show direct evidence of anti-phase domain boundaries (APB) present in these heterostructures. Experimentally identified 1/4<101> shifts determine the atomic structure of the observed APBs. The dominant non-bulk superexchange interactions are between 180° octahedral-Fe/O/octahedral-Fe sites which provide strong antiferromagnetic coupling across the defect interface resulting in non-bulk magnetic and magnetotransport properties.

Non-scarring patchy alopecia in patients with systemic lupus erythematosus differs from that of alopecia areata

Background

Non-scaring patchy alopecia associated with systematic lupus erythematosus (SLE) is sometimes mis-diagnosed as alopecia areata (AA).

Objectives

Our aim was to differentiate non-scarring patchy SLE alopecia features from patchy AA.

Methods

Clinical, dermatoscopic and histopathological data from 21 SLE patients with patchy alopecia were compared with data from 21 patients with patchy AA.

Results

Incomplete alopecia was common in SLE alopecia patches, while AA patches exhibited complete alopecia. Exclamation-mark hairs, black dots, broken hair and yellow dots were common to AA, while hair shaft thinning and hypopigmentation, angiotelectasis, peripilar sign, perifollicular red dots, white dots and honeycomb pigment patterns were more common in SLE. Interfollicular polymorphous vessels were the most common angiotelectasis presentation in the SLE alopecia patches, but interfollicular arborizing vessels were significantly more common in non-hair-loss-affected SLE regions and in AA hair-loss regions. During follow-up, increased vellus hair was the earliest feature that emerged after treatment both in SLE and AA, while the earliest feature that disappeared was hair shaft hypopigmentation in SLE and broken hair in AA. After treatment, no SLE patients had relapse of alopecia, while 41.7% of AA patients did.

Conclusion

Distinct clinical, dermatoscopic and histopathological features were found in SLE-associated alopecia regions, which were different from those of AA. Serological autoantibody tests are of value to confirm the differential diagnosis. Local angiotelectasis and vasculitis close to hair follicles may be involved in the pathogenesis of alopecia in SLE.

Nicotine induces alteration of H3K27 demethylase UTX in kidney cancer cell

Cigarette smoking is one of the most important risk factors for kidney cancer, but the molecular mechanism is poorly understood. To examine the expression change of histone H3 on lysine 27 trimethylase (H3K27me3) demethylases ubiquitously transcribed TPR gene on the X chromosome (UTX) in kidney cancer cell line 786-O after nicotine treatment, quantitative real-time-polymerase chain reaction and western blotting analysis were carried out. These results showed that nicotine can increase UTX messenger RNA and protein levels and also decrease the content of H3K27me3. The decreased content of H3K27me3 may activate specific gene expression and lead to kidney cancer. Future investigation on nicotine induced UTX expression and its epigenetic effect would deepen our understanding on nicotine toxicity and carcinogenicity.

Celecoxib attenuates systemic lipopolysaccharide-induced brain inflammation and white matter injury in the neonatal rats

Lipopolysaccharide (LPS)-induced white matter injury in the neonatal rat brain is associated with inflammatory processes. Cyclooxygenase-2 (COX-2) can be induced by inflammatory stimuli, such as cytokines and pro-inflammatory molecules, suggesting that COX-2 may be considered as the target for anti-inflammation. The objective of the present study was to examine whether celecoxib, a selective COX-2 inhibitor, can reduce systemic LPS-induced brain inflammation and brain damage. Intraperitoneal (i.p.) injection of LPS (2mg/kg) was performed in postnatal day 5 (P5) of Sprague-Dawley rat pups and celecoxib (20mg/kg) or vehicle was administered i.p. 5 min after LPS injection. The body weight and wire-hanging maneuver test was performed 24h after the LPS exposure, and brain injury was examined after these tests. Systemic LPS exposure resulted in an impairment of behavioral performance and acute brain injury, as indicated by apoptotic death of oligodendrocytes (OLs) and loss of OL immunoreactivity in the neonatal rat brain. Treatments with celecoxib significantly reduced systemic LPS-induced neurobehavioral disturbance and brain damage. Celecoxib administration significantly attenuated systemic LPS-induced increments in the number of activated microglia and astrocytes, concentrations of IL-1β and TNFα, and protein levels of phosphorylated-p38 MAPK in the neonatal rat brain. The protection of celecoxib was also associated with a reduction of systemic LPS-induced COX-2+ cells which were double labeled with GFAP+ (astrocyte) cells. The overall results suggest that celecoxib was capable of attenuating the brain injury and neurobehavioral disturbance induced by systemic LPS exposure, and the protective effects are associated with its anti-inflammatory properties.

Neonatal lipopolysaccharide exposure induces long-lasting learning impairment, less anxiety-like response and hippocampal injury in adult rats

Infection during early neonatal period has been shown to cause lasting neurological disabilities and is associated with the subsequent impairment in development of learning and memory ability and anxiety-related behavior in adults. We have previously reported that neonatal lipopolysaccharide (LPS) exposure resulted in cognitive deficits in juvenile rats (P21); thus, the goal of the present study was to determine whether neonatal LPS exposure has long-lasting effects in adult rats. After an LPS (1mg/kg) intracerebral (i.c.) injection in postnatal day 5 (P5) Sprague-Dawley female rat pups, neurobehavioral tests were carried out on P21 and P22, P49 and P50 or P70 and P71 and brain injury was examined at 66days after LPS injection (P71). Our data indicate that neonatal LPS exposure resulted in learning deficits in the passive avoidance task, less anxiety-like (anxiolytic-like) responses in the elevated plus-maze task, reductions in the hippocampal volume and the number of neuron-specific nuclear protein (NeuN)+ cells, as well as axonal injury in the CA1 region of the middle dorsal hippocampus in P71 rats. Neonatal LPS exposure also resulted in sustained inflammatory responses in the P71 rat hippocampus, as indicated by an increased number of activated microglia and elevation of interleukin-1β content in the rat hippocampus. This study reveals that neonatal LPS exposure causes persistent injuries to the hippocampus and results in long-lasting learning disabilities, and these effects are related to the chronic inflammation in the rat hippocampus.

Leukemoid reaction in malignant bone tumor patients - a retrospective, single-institution study

BACKGROUND

To the Authors' knowledge, the literature regarding leukemoid reaction in patients with malignant bone tumor is sparse, and most of patients with leukemoid reaction have poor prognosis.

AIM

To study the leukemoid reaction in malignant bone tumor patients.

MATERIALS AND METHODS

A total of 105 consecutive malignant bone tumor patients with a white blood cell count > 50,000/microL were retrospectively identified over a 4-years period (2007-2010). Those patients without a secondary cause of their leukocytosis were defined as having a paraneoplastic leukemoid reaction.

RESULTS

Three etiologies of the leukocytosis were found in those 105 patients: the major one was paraneoplastic leukemoid reaction which accounted for 56%; the second one was hematopoietic growth factors defect accounting for 30%; 14% patients were caused by infection and Tumor bone marrow involvement. The patients diagnosed with a paraneoplastic leukemoid reaction typically had neutrophil predominance (94.8%) and radiographic evidence of metastatic diseases (78%). They were clinically stable, but had a poor prognosis. 95% either died or were discharged to hospice within 12 weeks of their initial extreme leukocyte count. Both of the 2 (2%) patients who survived over 12 weeks received effective antineoplastic therapy.

CONCLUSIONS

Patients with typical paraneoplastic leukemoid reaction were clinically stable despite having large tumor burdens. However, clinical outcomes were poor unless receiving an effective antineoplastic treatment.

In-vivo effect of the combination of tnf and adriamycin against a human breast cell-line expressing the mdr-phenotype

The combined effect of tumor necrosis factor alpha (TNF) and adriamycin (ADR) on tumor cell killing was investigated in vivo. The human breast adenocarcinoma ADR-resistant MDA/ADR cells found to be resistant to in vitro TNF lysis and with an apparent index of resistance to ADR of 23 have been used. Treatment of MDA/ADR subcutaneous tumor bearing mice with PBS, TNF, ADR or the combination of TNF/ADR indicate that the combination of TNF and ADR treatment leads to a significant decrease in tumor growth while treatment with TNF was inactive and treatment with ADR was moderately active. Tumor cells were collected from mice treated with TNF/ADR combination and analysed by PCR for MnSOD and TNF ne expression. No induction of the expression of these genes, known to be involved in the regulation of TNF-induced cell killing, was noted following TNF/ADR combination treatment, suggesting that their products were not involved in the observed resistance.

PSGL-1/selectin and ICAM-1/CD18 interactions are involved in macrophage-induced drug resistance in myeloma

Chemoresistance is the major obstacle in multiple myeloma (MM) management. We previously showed that macrophages protect myeloma cells, on a cell contact basis, from melphalan or dexamethasone-induced apoptosis in vitro. In this study, we found that macrophage-mediated myeloma drug resistance was also seen with purified macrophages from myeloma patients' bone marrow (BM) in vitro and was confirmed in vivo using the human myeloma-SCID (severe combined immunodeficient) mouse model. By profiling differentially regulated and paired plasma membrane protein genes, we showed that PSGL-1 (P-selectin glycoprotein ligand-1)/selectins and ICAM-1/CD18 played an important role in macrophage-mediated myeloma cell drug resistance, as blocking antibodies against these molecules or genetic knockdown of PSGL-1 or ICAM-1 in myeloma cells repressed macrophages' ability to protect myeloma cells. Interaction of macrophages and myeloma cells via these molecules activated Src and Erk1/2 kinases and c-myc pathways and suppressed caspase activation induced by chemotherapy drugs. Thus, our study sheds new light on the mechanism of drug resistance in MM and provides novel targets for improving the efficacy of chemotherapy in patients.

Cellular stress response in Eca-109 cells inhibits apoptosis during early exposure to isorhamnetin

The flavonol aglycone isorhamnetin shows anti-proliferative activity in a variety of cancer cells. Previous work, from our laboratory showed that isorhamnetin inhibits the proliferation of human esophageal squamous carcinoma Eca-109 cells in vitro, but only after 72 h of exposure. This led us to propose that isorhamnetin exposure induces a cellular stress response that inhibits the antiproliferative and apoptotic effects of the compound during early exposure. To test this hypothesis, the present study examined the effects of isorhamnetin on Eca-109 cells during the first 72 h of exposure. Cell growth was assessed using the trypan blue exclusion assay, and expression of IκBα, NF-κB/p65, NF-κB/p50, phospho-Akt, Bcl-2, COX-2, Mcl-1, Bax, p53 and Id-1 were analyzed by Western blot. During the first 72 h of exposure, NF-κB/p65 and NF-κB/p50 accumulated in nuclei and expression of COX-2, Bcl-2 and Mcl-1 increased. In contrast, expression of IκBα and Bax fell initially but later increased. Expression of phospho-Akt and p53 showed no detectable change during the first 48 h. Pretreatment with the NF-κB inhibitor MG132 before exposure to isorhamnetin blocked the nuclear accumulation of p50 and p65, thereby inhibiting cell proliferation. These results show that during early exposure of Eca-109 cells to isorhamnetin, the NF-κB signaling pathway is activated and COX-2 expression increases, and this increase in expression partially inhibits isorhamnetin-induced apoptosis. Beyond 72 h of exposure, however, the apoptotic effect of isorhamnetin dominates, leading to inhibition of the NF-κB pathway and of cellular proliferation. These results will need to be taken into account when exploring the use of isorhamnetin against cancer in vivo.