Protective effects of pioglitazone against immunoglobulin deposition on heart of streptozotocin-induced diabetic rats

AIM

Peroxisome proliferator-activated receptor-γ (PPAR-γ) agonists have immunomodulatory and anti-inflammatory effects. The study investigated the autoimmune injuries of diabetic cardiomyopathy (DCM) and tested the hypothesis that PPAR-γ agonists suppress disordered immune responses in diabetic heart, thereby preventing evolution of DCM.

METHODS

STZ-induced diabetic rats were assigned to five groups: DM group, given no treatment; INS group, given insulin (4 U kg(-1) d(-1)); PIL group, given low dose pioglitazone (4 mg kg(-1) d(-1)); PIL/INS group, given both low dose pioglitazone and insulin; PIH group, given high dose pioglitazone (20 mg kg(-1) d(-1)). Normal rats (CON group) were also monitored as control. The pathologic abnormalities of hearts were observed. The immunoglobulin deposition was examined by immunohistochemistry and immunofluorescence.

RESULTS

At 16 weeks, interstitial fibrosis was shown in diabetic heart which was accompanied by plenty of inflammatory cells infiltrated. Pioglitazone therapy could ameliorate the cardiac injuries. Shown by immunohistochemistry, the difference of integrated optical density (IOD) of immunoglobulin deposition among each group had statistic significance. No obvious immunoglobulins were deposited in the intercellular substance of heart in CON group (IgA 290.8 ± 88.1, IgG 960.4 ± 316.0 and IgM 341.3 ± 67.9). But the deposition of immunoglobulins increased significantly in DM group (IgA 7,047.5 ± 1,328.3, P < 0.05; IgG 28,945.9 ± 5,160.7, P < 0.05 and IgM 8,580.8 ± 1,336.8, P < 0.05). Administration of pioglitazone greatly reduced the increased deposition in a dose-dependent fashion. Moreover, the statistical significance was the same with immunofluorescence analysis as with immunohistochemical examination.

CONCLUSIONS

The data suggest that disordered immune responses play an important role in the pathogenesis of DCM. Pioglitazone showed protective effects by inhibiting the immunoglobulin deposition on diabetic myocardium.

Epitope specificity of cross-clade neutralizing sera from Chinese HIV-1-positive individuals

Induction of broadly neutralizing antibody is considered important for an effective HIV-1 vaccine. Identification and characterization of broadly neutralizing antibodies in HIV-1-infected patients will facilitate our understanding of the immune correlates to protection and the design of an effective prophylactic vaccine. A number of studies to probe the specificity of antibodies in broadly neutralizing sera in the United States and Europe have been reported. However, little is known about and would be interesting to investigate the immunological characteristics of HIV-1-positive sera in China where non-clade B viruses are prevalent and the circulating viral subtypes are distinct and more complex than both the United States and Europe. Here, we screened 80 Chinese HIV-1-positive sera against a minipanel of pseudoviruses representing various circulating HIV-1 subtypes in China and identified 8 cross-clade neutralizing sera (CNsera). Immunological characterization of the sera showed that gp120-targeting antibodies with multiple epitope specificities contributed to the cross-clade neutralizing activity of these CNsera. V3-directed antibodies were prevalent in these CNsera, but did not mainly contribute to their neutralization breath and potency while CD4bs-specific, 2F5- and 4E10-like antibodies were rarely detected. 2G12-like neutralizing antibodies were more frequently detected in HIV-1 patients from China where recombinant subtype viruses are prevalent than in United States and Europe. One broadly neutralizing serum (Serum 45) was identified to contain antibodies with unknown epitope specificities that were sensitive to terminal glycan modifications on virus Env and insensitive to N160K mutagenesis, and correlated with the cross-clade neutralization activity of Serum 45.

Dynamic expression of secreted Frizzled-related protein 3 (sFRP3) in the developing mouse spinal cord and dorsal root ganglia

Wnt proteins have been implicated in regulating a variety of developmental processes in the CNS. Secreted Frizzled-related protein 3 (sFRP3) is a member of the sFRP family that can inhibit the Wnt signaling by binding directly to Wnts via their regions of homology to the Wnt-binding domain of Frizzleds. Recent studies suggested that sFRP3 plays an important role in cell proliferation and differentiation in various tissues. To understand the role of sFRP3 in neural development, we carried out detailed studies on the expression of sFRP3 in the developing nervous system. Our results revealed that sFRP3 is initially expressed in the ventricular zone of the spinal cord and dorsal root ganglia (DRG), and later in the dorsal horn of spinal cord and subpopulation of DRG neurons. The spatiotemporally dynamic expression ofsFRP3 strongly suggests that sFRP3 has potential functions in the sensory neuron genesis and sensory circuitry formation.

Peer assisted learning in surgical skills laboratory training: a pilot study

BACKGROUND

Peer assisted learning (PAL) has been rarely investigated in surgical skills training.

AIMS

Describe feedback residents give peers on surgical skills with and without guidelines, determine the association between feedback and actual performance, evaluate resident satisfaction with PAL.

METHOD

Participants evaluated peers using a validated knot-tying checklist and provided feedback on suturing without a guideline. Feedback comments were coded by type and an expert scored performance of each participant. Residents completed a satisfaction questionnaire.

RESULTS

Comments were generally specific. Feedback was twice as likely with the use of a guideline. Specific feedback correlated significantly with expert knot-tying score but not suturing score. Most participants felt peer feedback was helpful and were motivated to practice surgical skills after PAL sessions.

CONCLUSIONS

Surgical residents can provide high quality specific feedback to peers on surgical skills using performance guidelines. Further exploration of effective PAL methodology in surgical skills laboratory training is needed.

Gemcitabine and capecitabine as third-line treatment in patients with metastatic colorectal cancer after failure of irinotecan and oxaliplatin

620

Background: There is no standard chemotherapeutic regimen for patients with advanced colorectal cancer (CRC) progressing after combination regimens including irinotecan and oxaliplatin and having good performance status. 5-FU and gemcitabine are synergistic in preclinical studies of colon cancer cells. And gemcitabine also increases intracellular release of 5-FU from capecitabine. The aim of this study is to evaluate the efficacy and tolerance of the gemcitabine/capecitabine combination as third-line treatment for patients with advanced colorectal cancer.

Methods: Between May 2007 and September 2009, the data on 12 patients with metastatic colorectal cancer after failure of irinotecan- and oxaliplatin-containing regimens reviewed retrospectively. The median patient age was 54.0 years (range 37-77). The ECOG performance status was 0, 1 or 2. All patients has 2 or more previous chemotherapy. Patients received GemCap regimen (oral capecitabine 1,000 mg/m2 twice daily on days 1 to 14 plus Gem 1,000 mg/m2 on days 1 and 8 every 3 weeks). Eleven patients were evaluable for the response and all patients were evaluable for toxicity.

Results: No partial response was achieved and disease stabilization in 4 (36.4.3%) cases. Median progression-free survival and median overall survival were 9.1 weeks (range 3.0-18.0) and 22.3 weeks (range 10.5- 53.0). Four patients with disease stabilization had longer median progression-free survival than those with disease progression (13 weeks vs. 6.2 weeks). No toxic deaths occurred. Grade 3 toxicities were thrombocytopenia (in 2 patients), neutropenia (in 2 patients) and mucositis (in 1 patient), hand-foot syndrome (in 1 patient) and GI toxicity (in 2 patients).

Conclusions: The combination of gemcitabine and capecitabine was found to be a safe palliative regimen for heavily pretreated patients with metastatic CRC. Despite no patients had radiologic response, patients with disease stabilization achieved better progression-free survival. This regimen seems to be potentially effective regimen in the treatment of CRC.

No significant financial relationships to disclose.

Synergistic antitumor effect of TRAIL and adriamycin on the human breast cancer cell line MCF-7

The aim of the present study was to determine the effect of the combination of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and adriamycin (ADM) on the human breast cancer cell line MCF-7 and to identify potential mechanisms of apoptosis. Cell viability was analyzed by the MTT assay and the synergistic effect was assessed by the Webb coefficient. Apoptosis was quantified using the annexin V-FITC and propidium iodide staining flow cytometry. The mRNA expression of TRAIL receptors was measured by RT-PCR. Changes in the quantities of Bax and caspase-9 proteins were determined by Western blot. MCF-7 cells were relatively resistant to TRAIL (IC50 >10 microg/mL), while MCF-7 cells were sensitive to ADM (IC50 <10 microg/mL). A subtoxic concentration of ADM (0.5 microg/mL) combined with 0.1, 1, or 10 microg/mL TRAIL had a synergistic cytotoxic effect on MCF-7 cells, which was more marked with the combination of TRAIL (0.1 microg/mL) and ADM (0.5 microg/mL). In addition, the combined treatment with TRAIL and ADM significantly increased cell apoptosis from 9.8% (TRAIL) or 17% (ADM) to 38.7%, resulting in a synergistic apoptotic effect, which is proposed to be mediated by up-regulation of DR4 and DR5 mRNA expression and increased expression of Bax and caspase-9 proteins. These results suggest that the combination of TRAIL and ADM might be a promising therapy for breast cancer.

PI3K Pathway Activation in Breast Cancer Is Associated with the Basal-Like Phenotype and Cancer-Specific Mortality

Background: Current biological therapies for breast cancer are tailored to steroid hormone (ER, PR) and HER2 receptor status. Understanding the biological basis of resistance to current targeted therapies and the identification of new potential therapeutic targets is an ongoing challenge. The PI3K pathway is altered in a high proportion of breast cancers and may be associated with specific phenotypes and therapeutic resistance. We undertook an integrative study of mutational, copy number and expression analysis of key regulators of the PI3K pathway in a cohort of 292 invasive breast cancer patients with known treatment outcomes.Material and Methods: Mutations in 3 "hotspots" in exons 9 and 20 of the PIK3CA gene were determined by sequencing and PIK3CA gene copy number by qPCR. PTEN loss and Akt activation i.e. pAkt (Ser473) were assessed by immunohistochemistry using tissue microarrays. Cores were scored by 2 independent observers blinded to clinicopathological data and patient outcome and a histoscore calculated by multiplying the percent positive cells and staining intensity in a range 0-3. Standard statistical tests were applied to assess relationship between the measured parameters and patient outcome.Results: Alterations identified included PIK3CA mutations (12/168 i.e. 7%), PIK3CA copy number gain (28/209 i.e. 14%), PTEN loss (73/258 i.e. 28%) and AKT activation (62/258 i.e. 24%). Overall at least one parameter was altered in 72% i.e. 139 of 193 assessable primary breast cancers. PI3K pathway activation was significantly associated with ER negative (P=0.0008) and PR negative (P=0.006) status, high tumor grade (P=0.032) and a "basal-like" phenotype (P=0.01), where 92% (25/27) of tumors had an altered pathway. In univariate analysis PI3K pathway aberrations were associated with death from breast cancer however this relationship was not maintained in multivariate analysis. No association was identified between an activated pathway and outcome in tamoxifen- or chemotherapy-treated patients.Discussion: We conclude that &gt;70% of breast cancers have an alteration in at least one component of the PI3K pathway and this might be exploited to therapeutic advantage especially in "basal-like" cancers.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2123.

Pancreatic perfusion of healthy individuals and type 1 diabetic patients as assessed by magnetic resonance perfusion imaging

AIMS/HYPOTHESIS

Loss of pancreatic beta cell mass and function leads to the development of diabetes mellitus. Currently there is no technical way to non-invasively image islet function and mass. Murine models suggest that islets are highly vascularised organs that make a significant contribution to the total pancreatic blood flow. The current study was undertaken to test with arterial spin labelling (ASL) magnetic resonance imaging if islet mass and/or stimulation of human pancreatic islets by hyperglycaemia can differentially increase whole-pancreas perfusion, thereby distinguishing non-diabetic from type 1 diabetic patients.

METHODS

We assessed pancreatic blood flow using ASL at baseline, during a hyperglycaemia clamp study (glucose at 11 mmol/l) and during recovery to euglycaemia.

RESULTS

Seventeen healthy volunteers and seven type 1 diabetic patients were studied. In healthy volunteers we observed no change in pancreatic blood flow during the three phases of the study. A trend for an increase in blood flow was observed in the two control tissues, the liver and kidney. Similarly, there was no significant difference in blood flow during the three stages (baseline, hyperglycaemia and recovery) in diabetic patients and there was no significant difference observed between diabetic patients and normal volunteers.

CONCLUSIONS/INTERPRETATION

Our data suggest that in humans neither increased demand nor islet mass has a substantial influence on pancreatic perfusion. It is possible, however, that the current state-of-the art imaging technology employed in this study might not be sensitive enough to distinguish between a true effect and noise.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00280085.

Phase II clinical trial of XELOX as first line treatment for patients with unresectable or metastatic gastric cancer

15062

Background: The survival of advanced gastric cancer remains poor, while no chemotherapy regimen was recognized standard. Oxaliplatin and Capecitabine (Xeloda) have demonstrated promising antitumor efficacy in advanced colorectal cancer. The present study was conducted to further evaluate the efficacy and safety of XELOX (Oxaliplatin and Xeloda) regimen in gastric cancer. Methods: Patients with unresectable or metastatic gastric cancer were enrolled into this study. They all receive the XELOX regimens (Oxaliplatin 130mg/ m2 intravenously in 2 hours on day 1 followed by oral capecitabine 1000mg/ m2 twice daily for 14 days every 3 weeks).We evaluated the response every 2 cycles. Results: The median age of the total enrolled 45 patients was 55 years (range, 22–82 years), including 32 male and 13 female. They received a median of 5 cycles (range, 2–8 cycles) of XELOX. 21 of 45 patients (46.7%) achieved an objective response, 1 patient (2.2%) had completed response. 17 patients (37.8%) experienced stable disease. Median time to tumor progression (TTP) and median overall survival were not available yet due to the further follow-up needed. Most toxicity events were mild to moderate in XELOX regimen, with grade 3/4 neutropenia of 8.9 %, thrombocytopenia of 6.7%, anemia of 11.1%, hand-foot syndrome of 6.7 % and diarrhea of 6.7 %. Grade 3 neuropathy was 4.4%. The patients with advanced gastric cancer had a good tolerance to this chemotherapy. Conclusions: XELOX is a highly effective first-line treatment for unrsectable and metastatic gastric cancer. The response rates in this trial seems to be similar to those observed with FU/leucovorin/oxaliplatin combinations. XELOX is tolerable well in the treatment of advanced gastric cancer.

No significant financial relationships to disclose.

Increased production of reactive oxygen species contributes to motor neuron death in a compression mouse model of spinal cord injury

STUDY DESIGN

Experimental laboratory investigation of the role and pathways of reactive oxygen species (ROS)-mediated motor neuron cell death in a mouse model of compression spinal cord injury.

OBJECTIVES

To analyze ROS-mediated oxidative stress propagation and signal transduction leading to motor neuron apoptosis induced by compression spinal cord injury.

SETTING

University of Louisville Health Science Center.

METHODS

Adult C57BL/6J mice and transgenic mice overexpressing SOD1 were severely lesioned at the lumbar region by compression spinal cord injury approach. Fluorescent oxidation, oxidative response gene expression and oxidative stress damage markers were used to assay spinal cord injury-mediated ROS generation and oxidative stress propagation. Biochemical and immunohistochemical analyses were applied to define the ROS-mediated motor neuron apoptosis resulted from compression spinal cord injury.

RESULTS

ROS production was shown to be elevated in the lesioned spinal cord as detected by fluorescent oxidation assays. The early oxidative stress response markers, NF-kappaB transcriptional activation and c-Fos gene expression, were significantly increased after spinal cord injury. Lipid peroxidation and nucleic acid oxidation were also elevated in the lesioned spinal cord and motor neurons. Cytochrome c release, caspase-3 activation and apoptotic cell death were increased in the spinal cord motor neuron cells after spinal cord injury. On the other hand, transgenic mice overexpressing SOD1 showed lower levels of steady-state ROS production and reduction of motor neuron apoptosis compared to that of control mice after spinal cord injury.

CONCLUSION

These data together provide direct evidence to demonstrate that the increased production of ROS is an early and likely causal event that contributes to the spinal cord motor neuron death following spinal cord injury. Thus, antioxidants/antioxidant enzyme intervention combined with other therapy may provide an effective approach to alleviate spinal cord injury-induced motor neuron damage and motor dysfunction.

Negative refraction at infrared wavelengths in a two-dimensional photonic crystal

We report on the first experimental evidence of negative refraction at telecommunication wavelengths by a two-dimensional photonic crystal field. Samples were fabricated by chemically assisted ion beam etching in the InP-based low-index constrast system. Experiments of beam imaging and light collection show light focusing by the photonic crystal field. Finite-difference time-domain simulations confirm that the observed focusing is due to negative refraction in the photonic crystal area.