Citations

Abstract Reflux-induced injury promotes esophageal adenocarcinoma, one of the most rapidly increasing, highly lethal cancers in Western countries. Here, we investigate the efficacy of a combinatorial chemoprevention strategy for esophageal adenocarcinoma and characterize the underlying molecular mechanisms. Specifically, our approach involves the use of ursodeoxycholic acid (Urso) due to its ability to decrease injury-inducing bile salts in combination with Aspirin to mitigate the consequences of injury. We find that Urso-Aspirin combination reduces the risk of adenocarcinoma in vivo in animals with reflux, decreases the proliferation of esophageal adenocarcinoma cells, and downregulates a key cell cycle regulator, CDK2. Mechanistically, using cell growth, luciferase reporter, expression, and chromatin immunoprecipitation assays, we identify GLI1, a Hedgehog-regulated transcription factor, as a novel target of Urso-Aspirin combination. We show that GLI1 is upregulated during esophageal carcinogenesis, and GLI1 can bind to the CDK2 promoter and activate its expression. Although the Urso-Aspirin combination downregulates GLI1, the GLI1 overexpression not only abrogates the effect of this combination on proliferation but it also restores CDK-2 expression. These findings support that the chemopreventive effect of the Urso-Aspirin combination occurs, at least in part, through a novel GLI1-CDK2–dependent mechanism. To further understand the regulation of CDK2 by GLI1, both pharmacologic and RNAi-mediated approaches show that GLI1 is a transcriptional activator of CDK2, and this regulation occurs independent of Smoothened, the central transducer of the Hedgehog canonical pathway. Collectively, these results identify a novel GLI1-to-CDK2 pathway in esophageal carcinogenesis, which is a bona fide target for effective combinatorial chemoprevention with Urso and Aspirin. Cancer Res; 70(17); 6787–96. ©2010 AACR.

Key elements for determining alveolar-capillary membrane conductance (Dm) and pulmonary capillary blood volume (Vc) from the lung diffusing capacity (Dl) for carbon monoxide (DlCO) or for nitric oxide (DlNO) are the reaction rate of carbon monoxide with hemoglobin (θCO) and the DmCO/DlNOrelationship (α-ratio). Although a range of values have been reported, currently there is no consensus regarding these parameters. The study purpose was to define optimal parameters (θCO, α-ratio) that would experimentally substantiate calculations of Dm and Vc from the single-inspired O2tension [inspired fraction of O2(FiO2)] method relative to the multiple-FiO2method. Eight healthy men were studied at rest and during moderate exercise (80-W cycle). Dm and Vc were determined by the multiple-FiO2and single-FiO2methods (rebreathe technique) and were tabulated by applying previously reported θCOequations (both methods) and by varying the α-ratio (single-FiO2method) from 1.90 to 2.50. Values were then compared between methods throughout the examined α-ratios. Dm and Vc were critically dependent on the applied θCOequation. For the multiple-FiO2method, Dm was highly variable between θCOequations (rest and exercise); the range of Vc was less widespread. For the single-FiO2method, the θCOequation by Reeves and Park (1992) combined with an α-ratio between 2.08 and 2.26 gave values for Dm and Vc that most closely matched those from the multiple-FiO2method and were also physiologically plausible compared with predicted values. We conclude that the parameters used to calculate Dm and Vc values from the single-FiO2method (using DlCOand DlNO) can significantly influence results and should be evaluated within individual laboratories to obtain optimal values.

Abstract Between 1935 and 1974, 3598 episodes of head trauma among Olmsted County, Minnesota, residents resulted in 1097 skull fractures. Of these, 53% were simple, 16% were depressed, 12% were compound, and 19% were basilar. The age- and sex-adjusted incidence of skull fractures was 44.3 per 100,000 person-years overall, was somewhat greater in the urban than in the rural areas of Olmsted County, and was relatively stable for the final 30 years of the study. Age-specific incidence rates were highest for the very young, and simple linear fractures were the predominant type of skull fracture in this age group and among the elderly. The male:female ratio of incidence rates varied from 2.1:1 to 4.5:1 depending on fracture type. Motor vehicle accidents accounted for 38% of the skull fractures and were a particularly important cause among young males. Falls accounted for 37% of the skull fractures and were the major cause of fractures in the elderly and pediatric age groups. The results of this population-based study may be helpful in formulating recommendations for the evaluation and management of head-injured patients.

To further characterize spontaneous diabetes mellitus in cynomolgus macaques ( Macaca fascicularis) as a model for human non-insulin-dependent diabetes mellitus (NIDDM), we evaluated the morphologic characteristics of the endocrine pancreas of 4 diabetic and 12 age-matched nondiabetic cynomolgus macaques. In addition, the cDNA-predicted amino acid sequence for islet amyloid polypeptide (IAPP) of this species was determined. Islet amyloid deposits exhibiting typical congophilia and green birefringence were found in 4/4 diabetic animals and in 8/12 nondiabetics. Islet amyloid deposits were significantly more extensive in the diabetic macaques ( P = 0.001), in which they occupied a mean of 60% of the islet area. In contrast, in the nondiabetic group the maximum islet area occupied by amyloid was 24% (group mean = 6.8%), with four animals having no detectable islet amyloid. Amyloid deposits consistently showed immunoreactivity for IAPP but not for insulin. Comparisons between group means for diabetic versus nondiabetic macaques showed significantly greater islet area ( P = 0.01, 85,390 versus 36,540 μm 2 ) and significantly greater islet area fraction ( P = 0.02, 0.065 versus 0.032) for the diabetic group. The cDNA-predicted amino acid sequence for cynomolgus IAPP was identical to that previously reported for pig-tail macaques ( M. nemestrina) and had 92%, 86%, and 84% amino acid sequence identity with human, domestic cat, and murine IAPPs, respectively. These findings support the use of cynomolgus macaques as an animal model of human NIDDM.

Abstract We have compared two assays for osteocalcin (BGP, bone gla protein), one based on a monoclonal antibody, the other based on a polyclonal serum, in an effort to better understand the factors that contribute to the wide variation reported for osteocalcin normal ranges. The two assays compared well using serum samples, with a correlation coefficient of 0.9071 (n = 48). However, the monoclonal antibody assay returns values increased over the polyclonal assay by approximately 1.5-fold. Gel permeation studies indicate that these larger values are due primarily to increased reactivity in the monoclonal assay with high- and low-molecular-weight forms of osteocalcin in plasma; both assays give similar reactions to intact osteocalcin. Analysis of samples from individuals with increased bone resorption due to parathyroid hormone administration reveals that the decrease seen in osteocalcin values after hormone infusion occurs primarily in the fraction that corresponds to intact osteocalcin. During the course of these studies, we re-evaluated the extinction coefficient for osteocalcin, arriving at the value E = 1.33 mg/ml−1, cm−1. We also observed a significant negative interference in both assays (and a commercial assay) caused by hemolysis. This interference is due to proteolysis of osteocalcin by enzymatic activity released from the lysed red cells.

Abstract Seasonal variation in physical activity, back extensor muscle strength (BES), and bone mineral density (BMD) of the lumbar spine was studied in 65 healthy postmenopausal women. Physical activity score (PAS) was assessed with an ordinal scale (0-18); this score and the BES were obtained monthly for 2 years (25 readings). BMD values were obtained semiannually (5 readings). A periodic (cosine) regression model was fit to each subject's PAS and BES data to obtain individual estimates of the annual peak day d and the average annual range due to seasonality. There was a strong (P < 0.001) seasonal pattern in physical activity; August 3 was the average peak day, and the seasonal range was 2.0 PAS units. There was modest (P = 0.047) seasonality in BES; June 6 was the estimated peak day, and the seasonal range was 8.22 pounds (about 7% of the mean). BMD averaged 0.015 g/cm2 higher in August through November than February through May (P = 0.002), and the highest monthly average BMD was in August. This seasonal range of 1.4% is larger than the average annual decline with age in BMD observed in longitudinal studies of postmenopausal women. The results of this study have important implications for the planning of longitudinal studies involving changes in physical activity or bone mass in geographic areas with diverse seasons.

Purpose The phosphatidylinositol 3-kinase/mammalian target of rapamycin (mTOR) signal transduction pathway controls cell proliferation and survival. Everolimus is an oral agent targeting raptor mTOR (mTORC1). The trial's goal was to determine the antitumor activity and safety of single-agent everolimus in patients with relapsed/refractory Waldenström macroglobulinemia (WM). Patients and Methods Eligible patients had measurable disease (immunoglobulin M monoclonal protein > 1,000 mg/dL with > 10% marrow involvement or nodal masses > 2 cm), a platelet count more than 75,000 × 10 6 /L, a neutrophil count more than 1,000 × 10 6 /L, and a creatinine and bilirubin less than 2 × the laboratory upper limit of normal. Patients received everolimus 10 mg orally daily and were evaluated monthly. Tumor response was assessed after cycles 2 and 6 and then every three cycles until progression. Results Fifty patients were treated. The median age was 63 years (range, 43 to 85 years). The overall response rate (complete response plus partial remission [PR] plus minimal response [MR]) was 70% (95% CI, 55% to 82%), with a PR of 42% and 28% MR. The median duration of response and median progression-free survival (PFS) have not been reached. The estimated PFS at 6 and 12 months is 75% (95% CI, 64% to 89%) and 62% (95% CI, 48% to 80%), respectively. Grade 3 or higher related toxicities were observed in 56% of patients. The most common were hematologic toxicities with cytopenias. Pulmonary toxicity occurred in 10% of patients. Dose reductions due to toxicity occurred in 52% of patients. Conclusion Everolimus has high single-agent activity with an overall response rate of 70% and manageable toxicity in patients with relapsed WM and offers a potential new therapeutic strategy for this patient group.

Abstract Serum bone Gla-prolein (BGP), also called osteocalcin, is a specific and sensitive measure of bone turnover in a variety of metabolic bone disorders. Although some BGP diffuses into the circulation after synthesis by osteoblasts, most is incorporated into bone matrix where it remains until bone is resorbed. Thus, serum BGP could reflect bone formation, bone resorption, or a combination of both. The relationship of serum BGP to the components of bone turnover was evaluated in 18 normal women (mean age 48 yr; range 30-70) who received a continuous 24-h intravenous infusion of the 1-34 synthetic fragment of bovine parathyroid hormone. Mean ± SE for urinary hydroxyproline excretion, an index of bone resorption, increased (from 22.7 ± 2.2 to 38.5 ± 3.7 μg/100 ml glomerular filtrate [GF], p < .001), whereas levels of serum alkaline phosphatase, an index of bone formation, were unchanged (from 20 ± 1 to 20 ± 1 U/liter, NS). Despite the increase in bone resorption, levels of serum BGP decreased (from 8.8 ± 0.8 to 6.8 ng/dl, p < .001). The data suggest that circulating levels of BGP are a measure of bone formation but, at least in subjects with normal renal function, not a measure of bone resorption. Presumably BGP in bone matrix is degraded during osteoclastic resorption into fragments that either are not recognized by an antiserum raised against the native molecule or are rapidly cleared from the circulation.