Distinct clinical and metabolic deficits in PCA and AD are not related to amyloid distribution

BACKGROUND/OBJECTIVE

Patients with posterior cortical atrophy (PCA) often have Alzheimer disease (AD) at autopsy, yet are cognitively and anatomically distinct from patients with clinical AD. We sought to compare the distribution of β-amyloid and glucose metabolism in PCA and AD in vivo using Pittsburgh compound B (PiB) and FDG-PET.

METHODS

Patients with PCA (n = 12, age 57.5 ± 7.4, Mini-Mental State Examination [MMSE] 22.2 ± 5.1), AD (n = 14, age 58.8 ± 9.6, MMSE 23.8 ± 6.7), and cognitively normal controls (NC, n = 30, age 73.6 ± 6.4) underwent PiB and FDG-PET. Group differences in PiB distribution volume ratios (DVR, cerebellar reference) and FDG uptake (pons-averaged) were assessed on a voxel-wise basis and by comparing binding in regions of interest (ROIs).

RESULTS

Compared to NC, both patients with AD and patients with PCA showed diffuse PiB uptake throughout frontal, temporoparietal, and occipital cortex (p < 0.0001). There were no regional differences in PiB binding between PCA and AD even after correcting for atrophy. FDG patterns in PCA and AD were distinct: while both groups showed hypometabolism compared to NC in temporoparietal cortex and precuneus/posterior cingulate, patients with PCA further showed hypometabolism in inferior occipitotemporal cortex compared to both NC and patients with AD (p < 0.05). Patients with AD did not show areas of relative hypometabolism compared to PCA.

CONCLUSIONS

Fibrillar amyloid deposition in PCA is diffuse and similar to AD, while glucose hypometabolism extends more posteriorly into occipital cortex. Further studies are needed to determine the mechanisms of selective network degeneration in focal variants of AD.

Effect of filler geometry on coefficient of thermal expansion in carbon nanofiber reinforced epoxy composites

This study involves the investigation of the geometry effect of nano-fillers on thermally induced dimensional stability of epoxy composites by experimentally evaluating the linear coefficient of thermal expansion (CTE). Carbon nanofibers (CNF) were chosen as the filler in epoxy matrix to investigate the effect of an aspect ratio on the CTE of the nanocomposites at three different volume fractions of 0.5, 1, and 2% of the nano-filler. The composites were fabricated using a mechanical mixing method. The CTE values were evaluated by measuring thermal strains of the composites and also compared with a micromechanics model. It was observed that the composites with short CNF (average L/d = 10) show better thermal stability than one of the composites with long CNF (average L/d = 70), and the thermal stability of the composites was proportional to the volume fraction of the filler in each composite. In addition, the CTE of mutliwalled carbon nanotubes (MWNT) reinforced epoxy composites was evaluated and compared with the CTE of the CNF reinforced composites. Interestingly, the MWNT reinforced composites show the greatest thermal stability with an 11.5% reduction in the CTE over the pure epoxy. The experimental data was compared with micromechanics model.

Development of murine leukemia virus-based retroviral vectors with a minimum possibility of cis-activation

The possibility of insertional mutagenesis in retroviral gene therapy can be reduced by using a vector lacking the enhancer sequence present in the U3 of the long-terminal repeats. However, such vectors suffer from many pitfalls. We attempted to improve a murine leukemia virus-based retroviral vector containing the enhancer-free U3, first by making it easier to construct a producer line and then by introducing the cellular RPL10 promoter as an internal promoter. The reverse orientation of the expression cassette of the transgene was found to give higher transducing titer and higher-level gene expression. The deletion analysis revealed that the 54-bp-long sequence of U3 (34 and 20 bp present at 5' and 3' extreme ends, respectively) was sufficient for the functions of retroviral vectors. The data from the in vitro cell culture assay indicated that the final construct, ROK, containing all these features, had little cis-activation activity, even if it was placed right upstream from the RNA start site of the neighboring gene. Our data suggested that the newly developed vector might provide increased safety, while still producing high viral titer from a stable producer line and high-level gene expression in various target cells including human CD34(+) stem cells.

Clinical significances of preoperative serum IL-6 and CRP level in operable gastric cancer

e15591

Background: The interleukin (IL)-6 pathway is one of the mechanisms liking inflammation and angiogenesis to malignancy. As the C-reactive protein (CRP) is representative marker of inflammation, recently CRP has been reported to be associated with processing of disease in many cancers. This study aims to determine the preoperative serum levels of IL-6 and CRP in gastric carcinoma, and correlate them with disease status and prognosis. Methods: A total of 115 patients receiving gastrectomy entered this study. Serum level of IL-6 was measured by using Enzyme-Linked Immuno-Sorbent Assay (ELISA) and CRP was measured by using immunoturbidimetry. Histological findings were included depth of tumor invasion, lymph node (LN) metastasis, and TNM stage (AJCC Stage Groupings The staging systems; Primary tumor, regional LN, metastasis). Results: The more cancer invasion and stage are high, the more preoperative serum IL-6 levels are high. IL-6 level was correlated with depth of invasion (P=0.006) and TNM stage (P<0.001). Preoperative CRP level also correlated with depth of invasion (P<0.001), TNM stage (P=0.001), and presence of peritoneal seeding metastasis (positive 0.66 ± 0.69 mg/dL, negative 0.20 ± 0.29 mg/dL; P<0.001). When we put cutoff value of IL-6 level (6.77 pg/dL) by ROC curve, although patients’ survival did not reach the median value, it shows significant difference in time to progression (TTP; P<0.001) and overall survival (OS; P<0.010). But, CRP did not show significance to patients’ TTP and OS. Conclusions: Preoperative serum IL-6 and CRP levels might be markers of tumor invasion and TNM stage. Preoperative high IL- 6 level was a poor prognostic factor of disease recurrence and overall survival in patients with gastric cancers.

No significant financial relationships to disclose.

Clinical implication of ERCC1 overexpression in advanced biliary tract adenocarcinoma patients treated with platinum-based palliative chemotherapy

e22018

Background: Several clinical studies have shown that Excision repair cross-complementation group1 (ERCC1) overexpression is associated with resistance to platinum-based chemotherapy and poor prognoses in several tumors. However these studies have never been tried for biliary tract cancer. The aim of this study was to evaluate the association between ERCC1 expression and treatment outcomes in advanced biliary tract adenocarcinoma patients treated with platinum-based palliative chemotherapy. Methods: We analyzed 45 patients with histologically confirmed adenocarcinoma of biliary tract at 5 institutions between January 2002 and March 2008. ERCC1 expression was assessed by immunohistochemistry from biopsy specimens. Results: ERCC1 expression was positive in 17 of 45 specimens (37.8%). 26 (57.8%) of 45 patients showed clinical benefits(including complete response, partial response and stable disease). Among 26 patients who obtained clinical benefits, seven (27%) were positive for ERCC1 expression and ninety (73%) were negative (p=0.079). With a median follow-up of 6.6 months (range, 0.9–39.4 months), median Progression free survival (PFS) and Overall survival (OS) were 4.4 months (95% CI, 3.2–5.6 months) and 8.5 months (95% CI, 6.1–10.9 months), respectively, for the total study population. On univariate analysis, PFS was 2.3 months for patients with ERCC1 positive tumor and 5.3 months for those with ERCC1 negative tumor (P = 0.053). However OS was significantly longer in the ERCC1-negative group than in the ERCC1-positive group (10.0 vs 4.4 months, respectively; P = 0.001). Other factors affecting the prolongation of OS were objective response rate (P = 0.016) and clinical benefits (P = 0.001). A Cox proportional hazard model showed that negative ERCC1 expression (hazard ratio 0.405, 95% CI, 0.200–0.820; P = 0.012) and clinical benefit (hazard ratio 0.183, 95% CI 0.080–0.420; P = 0.001) were significant independent prognostic factors for the prolongation of survival. Conclusions: These results suggest that advanced biliary tract adenocarcinoma patients with ERCC1-negative tumors show a survival benefit from palliative chemotherapy with a platinum- containing regimen.

No significant financial relationships to disclose.

Postoperative LV5FU2 combination chemotherapy in patients with curative resected advanced gastric cancer

e15660

Background: To illuminate the effect and toxicity of fortnightly low-dose leucovorin(LV) and fluorouracil(5FU) bolus plus continuous infusion(LV5FU2) postoperative chemotherapy(adjuvant) in patients with curative resected, advanced gastric cancer. Methods: Total 40 patients were enrolled in this study. All patients received LV 20mg/m2(bolus), 5FU 400mg/m2(bolus), 5FU 600mg/m2(24-hour continuous infusion) on day 1, 2, 15, and 16, every 4 weeks(LV5FU2), total 6 cycles. Results: Postoperative chemotherapy was initiated median 19 days after surgery. Total of 238 cycles were administered and median follow-up was 602 days. The median disease-free survival time was 728 days (95% CI, 411∼1045) and 2-year overall survival was 77%. Relapses were reported in 18 (45%) of the patients : Two of 9 patients relapsed in stage IIIA (22.2%), seven of 12 patients relapsed in stage IIIB (58.3%) and nine of 17 patients relapsed in stage IV (52.9%). They were all distant relapsed. Eight patients died. 7 patients died as a result of cancer progression and 1 patient suicided while receiving palliative chemotheraphy for cancer relapse. The grade 3∼4 toxicity of neutropenia 8.4% and anemia 0.4%, neutropenic fever 0.4% were observed. Conclusions: Postoperative LV5FU2 adjuvant chemotherapy is effective and tolerable for the patients with curative resected, advanced gastric cancer.

No significant financial relationships to disclose.