Interobserver repeatability of heidelberg retinal flowmetry using pixel-by-pixel analysis.

PURPOSE: To determine the interobserver reproducibility of Heidelberg retinal flowmeter (HRF) blood flow measurements using independently selected study areas for pixel-by-pixel analysis. PATIENTS AND METHODS: Blood flow measurements were performed on 257 scans from 15 patients, 14 of whom had glaucoma or ocular hypertension. HRF was used to record capillary perfusion in a 2560x640 mum area of the supratemporal peripapillary region and pixel-by-pixel analysis was performed from an area adjacent to the optic disc with a minimum of 1600 pixels. Each observer independently selected the area for analysis. The percentage of pixels with <1 arbitrary unit of flow (no flow) and 10, 25, 50, 75, and 90th percentiles of flow values was calculated. Interobserver variability was assessed by estimating the intraclass correlation coefficient (ICC) and its 95% confidence interval. Bland-Altman plots of the difference between the 2 physicians versus the average of the 2 physicians for each outcome were created. RESULTS: ICC was 0.79 (range: 0.74 to 0.83) for mean flow values. For 0, 10, 25, 50, 75, and 90th percentiles of flow, the ICC was 0.67 (0.60 to 0.73), 0.74 (0.68 to 0.79), 0.82 (0.78 to 0.86), 0.85 (0.82 to 0.88), 0.85 (0.81 to 0.88), and 0.77 (0.72 to 0.82), respectively. Zero flow pixels had a nonsignificant mean difference between observers (P=0.542), whereas the remainder of the flow values demonstrated significant mean differences. CONCLUSIONS: This study demonstrates that independent observers can review high-quality HRF scans and may produce different absolute values while retaining strong consistency of agreement when independently selecting areas for analysis using the pixel-by-pixel method.

Effect of celecoxib and the novel anti-cancer agent, dimethylamino-parthenolide, in a developmental model of pancreatic cancer.

OBJECTIVES: Cancer of the exocrine pancreas is the fourth leading cause of cancer-related deaths in the United States. The efficacy of a novel bioavailable anticancer agent, dimethylamino-parthenolide (DMAPT), and the cyclooxygenase 2 inhibitor, celecoxib, was evaluated in a carcinogen-induced developmental model of pancreatic cancer. METHODS: Syrian golden hamsters were injected with N-nitrosobis(2-oxopropyl)amine, once weekly for 6 weeks. Upon the first injection, hamsters were randomized as follows: placebo, low-/high-dose DMAPT (20 and 40 mg/kg per day), low-/high-dose celecoxib (10and 50 mg/kg per day), or combination DMAPT/celecoxib (low/low, high/high). RESULTS: The 32-week trial showed that 40 mg/kg DMAPT alone significantly decreased the size of gross pancreatic cancers relative to placebo. No significant difference in gross tumor number was observed between the treatment groups and placebo with the exception of 50 mg/kg celecoxib with a higher tumor incidence; this group also exhibited lower lymphotactin levels suggestive of decreased immune surveillance. Tumor invasion into adjacent organs and metastasis were not observed in the DMAPT/celecoxib treatment groups. Drug targets including prostaglandin E2, prostaglandin E2 metabolite and activated nuclear factor kappaB were significantly decreased. CONCLUSIONS: Dimethylamino-parthenolide and celecoxib have the potential to be novel chemotherapeutic agents for pancreatic cancer; however, further optimization or the use of other modalities may be required for chemoprevention.

PGE(2) in pancreatic cyst fluid helps differentiate IPMN from MCN and predict IPMN dysplasia.

Current management of intraductal papillary mucinous neoplasm (IPMN) according to recently published International Consensus Guidelines depends upon distinguishing it from mucinous cystic neoplasms (MCNs). We have previously shown that prostaglandin E(2) (PGE(2)) is increased in pancreatic cancer tissue over normal controls. Thus, we hypothesized that PGE(2) level in pancreatic fluid differentiates IPMN and MCN and is a biomarker of IPMN dysplasia. Pancreatic fluid was collected in 65 patients at the time of endoscopy (EUS or ERCP) or operation (OR) and analyzed by PGE(2) enzyme-linked immunosorbent assay (ELISA). PGE(2) level was correlated with surgical pathologic diagnosis and dysplastic stage. Mean PGE(2) level (pg/microl) in IPMNs (2.2 +/- 0.6) was greater than in MCNs (0.2 +/- 0.1) (p < 0.05). Mean PGE(2) level of IPMN by dysplastic stage was 0.1 +/- 0.01 (low grade), 1.2 +/- 0.6 (medium grade), 4.4 +/- 0.9 (high grade), and 5.0 +/- 2.3 (invasive). Among invasive IPMN, PGE(2) level dropped in advanced cases with pancreatic ductal obstruction by tumor (0.3 +/- 0) vs non-obstructed (8.6 +/- 2.9). PGE(2) level may help in distinguishing IPMN from MCN in patients with known mucinous lesions. PGE(2) level may also be an indicator of malignant progression of IPMN before ductal obstruction by tumor. Prospective evaluation will be necessary to evaluate the clinical role of PGE(2) level in pancreatic fluid.

Effect of celecoxib and novel agent LC-1 in a hamster model of lung cancer.

BACKGROUND: Lung cancer is the leading cause of cancer deaths in the United States. Inflammatory molecules, cyclooxygenase-2 (COX-2) and nuclear factor kappa B (NF-kappaB) have been implicated in lung carcinogenesis. The therapeutic potential of celecoxib, a COX-2 selective inhibitor, and LC-1, a pro-apoptotic drug with accompanying inhibition of NF-kappaB, were investigated. MATERIALS AND METHODS: Syrian golden hamsters (n = 140) underwent N-nitroso-bis(2-oxopropyl)amine (BOP) injection weekly for 6 wk. Hamsters were randomized into seven groups: placebo and low/high doses of LC-1, celecoxib, and LC-1/celecoxib. Treatments were given via orogastric lavage for 32 wk. Immunohistochemistry was used to determine COX-2 expression and NF-kappaB activity. Ki-67 labeling was used as an index of proliferation. COX activity was measured by prostaglandin E(2) enzyme-linked immunosorbent assay. RESULTS: BOP successfully induced lung adenocarcinoma in 63% of placebo animals. Lung tumors strongly expressed COX-2 and NF-kappaB. Prostaglandin E(2) levels were decreased in celecoxib compared with placebo groups (P < 0.05) reflecting suppression of COX activity, but no decrease in NF-kappaB was seen as measured by immunohistochemistry in the tumors. There was no significant difference in tumor size, tumor incidence, or tumor proliferation index between placebo and treatment groups. CONCLUSIONS: Carcinogen exposure results in increased COX-2 and NF-kappaB expression and suggests a role in carcinogenesis. Celecoxib and LC-1 did not have any effect in preventing lung cancer development when co-administered with and continued after the carcinogen BOP. Higher doses that can result in suppression of NF-kappaB activity will need to be explored to determine the viability of this approach to prevent lung cancer development.

Suppression of pancreatic tumor growth by combination chemotherapy with sulindac and LC-1 is associated with cyclin D1 inhibition in vivo.

The design of novel targeted or combination therapies may improve treatment options for pancreatic cancer. Two targets of recent interest are nuclear factor-kappaB (NF-kappaB) and cyclooxygenase (COX), known to be activated or overexpressed, respectively, in pancreatic cancer. We have previously shown that parthenolide, a proapoptotic drug associated with NF-kappaB inhibition, enhanced the growth suppression of pancreatic cancer cells by the COX inhibitor sulindac in vitro. In the present study, a bioavailable analogue of parthenolide, LC-1, and sulindac were evaluated in vivo using a xenograft model of human pancreatic cancer. Treatment groups included placebo, low-dose/high-dose LC-1 (20 and 40 mg/kg), low-dose/high-dose sulindac (20 and 60 mg/kg), and low-dose combination LC-1/sulindac (20 mg/kg each). In MiaPaCa-2 xenografts, tumor growth was inhibited by either high-dose sulindac or LC-1. In BxPC-3 xenografts, tumor size was significantly reduced by treatment with the low-dose LC-1/sulindac combination or high-dose sulindac alone (P < 0.05). Immunohistochemistry of BxPC-3 tumors revealed a significant decrease in Ki-67 and CD31 staining by high-dose sulindac, with no significant changes in COX-1/COX-2 levels or activity in any of the treatment groups. NF-kappaB DNA-binding activity was significantly decreased by high-dose LC-1. Cyclin D1 protein levels were reduced by the low-dose LC-1/sulindac combination or high-dose sulindac alone, correlating with BxPC-3 tumor suppression. These results suggest that LC-1 and sulindac may mediate their antitumor effects, in part, by altering cyclin D1 levels. Furthermore, this study provides preclinical evidence for the therapeutic efficacy of these agents.

Parthenolide cooperates with NS398 to inhibit growth of human hepatocellular carcinoma cells through effects on apoptosis and G0-G1 cell cycle arrest.

Chemotherapy to date has not been effective in the treatment of human hepatocellular carcinoma. More effective treatment strategies may involve combinations of agents with activity against hepatocellular carcinoma. Parthenolide, a nuclear factor-kappaB (NF-kappaB) inhibitor, and NS398, a cyclooxygenase (COX)-2 inhibitor, have been shown to individually suppress the growth of hepatocellular carcinoma cells in vitro. To investigate their effects in combination, three human hepatocellular carcinoma lines (Hep3B, HepG2, and PLC) were treated with parthenolide and/or NS398. Parthenolide (0.1-10 micromol/L) and NS398 (1-100 micromol/L) each caused concentration-dependent growth inhibition in all cell lines. The addition of parthenolide to NS398 reduced the concentration of NS398 required to inhibit hepatocellular carcinoma growth. Because parthenolide and COX-2 inhibitors have been reported to influence NF-kappaB activity, the effects on this pathway were investigated. The combination of parthenolide/NS398 inhibited phosphorylation of the NF-kappaB-inhibitory protein IkappaBalpha and increased total IkappaBalpha levels. NF-kappaB DNA-binding and transcriptional activities were inhibited more by the combination than the single agents in Hep3B and HepG2 cells but not in PLC cells. The response of PLC cells to NS398 was augmented by p65 small interfering RNA to inhibit NF-kappaB p65 protein expression. The combination of parthenolide/NS398 increased apoptosis only in PLC cells, suggesting that the combination may decrease the apoptotic threshold in these cells. In Hep3B and HepG2 cells, combination treatment with NS398/parthenolide altered the cell cycle distribution resulting in more G0-G1 accumulation. Cyclin D1 levels were further decreased by combination treatment in all cell lines, correlating with the cell cycle alterations. Our results suggest that parthenolide may be effective in combination with COX-2 inhibitors for the treatment of hepatocellular carcinoma.