Acute and chronic effects of dietary fatty acids on cholecystokinin expression, storage and secretion in enteroendocrine STC-1 cells

Cholecystokinin (CCK) is a peptide hormone secreted from the I-cells of the intestine and it has important physiological actions related to appetite regulation and satiety. In this study we used STC-1 cells to investigate the effects of common dietary-derived fatty acids (FAs) on I-cell secretory function and metabolism. We extend earlier studies by measuring the acute and chronic effects of 11 FAs on CCK secretion, cellular CCK content, CCK mRNA levels, cellular DNA synthesis, cellular viability and cytotoxicity. FAs were selected in order to assess the importance of chain length, degree of saturation, and double bond position and conformation. The results demonstrate that secretory responses elicited by dietary FAs are highly selective. For example, altering the conformation of a double bond from cis to trans (i.e. oleic acid versus elaidic acid) completely abolishes CCK secretion. Lauric acid appears to adversely affect I-cell metabolism and arachidonic acid suppresses DNA synthesis. Our studies reveal for the first time that conjugated linoleic acid isoforms are particularly potent CCK secretagogues, which also boost intracellular stores of CCK. These actions of conjugated linoleic acid may explain satiating actions observed in dietary intervention studies.

Global down-regulation of HOX gene expression in PML-RAR alpha(+) acute promyelocytic leukemia identified by small-array real-time PCR

Acute promyelocytic leukemia (APL) is associated with a reciprocal and balanced translocation involving the retinoic acid receptor-alpha (RARalpha). All-trans retinoic acid (ATRA) is used to treat APL and is a potent morphogen that regulates HOX gene expression in embryogenesis and organogenesis. HOX genes are also involved in hematopoiesis and leukemogenesis. Thirty-nine mammalian HOX genes have been identified and classified into 13 paralogous groups clustered on 4 chromosomes. They encode a complex net-Work of transcription regulatory proteins whose precise targets remain poorly understood. The overall function of the network appears to be dictated by gene dosage. To investigate the mechanisms involved in HOX gene regulation in hematopoiesis and leukemogenesis by precise measurement of individual HOX genes, a small-array real-time HOX (SMART-HOX) quantitative polymerase chain reaction (PCR) platform was designed and validated. Application of SMART-HOX to 16 APL bone marrow samples revealed a global down-regulation of 26 HOX genes compared with normal controls. HOX gene expression was also altered during differentiation induced by ATRA in the PML-RARalpha(+) NB4 cell line. PML-RARalpha, fusion proteins have been reported to act as part of a repressor complex during myelold cell differentiation, and a model linking HOX gene expression to this PML-RARalpha repressor complex is now proposed.

Nasal potential difference to detect Na+ channel dysfunction in acute lung injury

Pulmonary fluid clearance is regulated by the active transport of Na+ and Cl- through respiratory epithelial ion channels. Ion channel dysfunction contributes to the pathogenesis of various pulmonary fluid disorders including high-altitude pulmonary edema (HAPE) and neonatal respiratory distress syndrome (RDS). Nasal potential difference (NPD) measurement allows an in vivo investigation of the functionality of these channels. This technique has been used for the diagnosis of cystic fibrosis, the archetypal respiratory ion channel disorder, for over a quarter of a century. NPD measurements in HAPE and RDS suggest constitutive and acquired dysfunction of respiratory epithelial Na+ channels. Acute lung injury (ALI) is characterized by pulmonary edema due to alveolar epithelial-interstitial-endothelial injury. NPD measurement may enable identification of critically ill ALI patients with a susceptible phenotype of dysfunctional respiratory Na+ channels and allow targeted therapy toward Na+ channel function. text of link

Pim2 cooperates with PML-RAR alpha to induce acute myeloid leukemia in a bone marrow transplantation model

Although the potential role of Pim2 as a cooperative oncogene has been well described in lymphoma, its role in leukemia has remained largely unexplored. Here we show that high expression of Pim2 is observed in patients with acute promyelocytic leukemia (APL). To further characterize the cooperative role of Pim2 with promyelocytic leukemia/retinoic acid receptor alpha (PML/RAR alpha), we used a well-established PML-RAR alpha (PR alpha) mouse model. Pim2 coexpression in PR alpha-positive hematopoietic progenitor cells (HPCs) induces leukemia in recipient mice after a short latency. Pim2-PR alpha cells were able to repopulate mice in serial transplantations and to induce disease in all recipients. Neither Pim2 nor PR alpha alone was sufficient to induce leukemia upon transplantation in this model. The disease induced by Pim2 overexpression in PR alpha cells contained a slightly higher fraction of immature myeloid cells, compared with the previously described APL disease induced by PR alpha. However, it also clearly resembled an APL-like phenotype and showed signs of differentiation upon all-trans retinoic acid (ATRA) treatment in vitro. These results support the hypothesis that Pim2, which is also a known target of Flt3-ITD (another gene that cooperates with PML-RAR alpha), cooperates with PR alpha to induce APL-like disease. (Blood. 2010; 115(22): 4507-4516)

Elucidating the molecular physiopathology of acute respiratory distress syndrome in severe acute respiratory syndrome patients

Acute respiratory distress syndrome (ARDS) is a severe form of acute lung injury. It is a response to various diseases of variable etiology, including SARS-CoV infection. To date, a comprehensive study of the genomic physiopathology of ARDS (and SARS) is lacking, primarily due to the difficulty of finding suitable materials to study the disease process at a tissue level (instead of blood, sputa or swaps). Hereby we attempt to provide such study by analyzing autopsy lung samples from patient who died of SARS and showed different degrees of severity of the pulmonary involvement. We performed real-time quantitative PCR analysis of 107 genes with functional roles in inflammation, coagulation, fibrosis and apoptosis: some key genes were confirmed at a protein expression level by immunohistochemistry and correlated to the degree of morphological severity present in the individual samples analyzed. Significant expression levels were identified for ANPEP (a receptor for CoV), as well as inhibition of the STAT1 pathway, IFNs production and CXCL10 (a T-cell recruiter). Other genes unassociated to date with ARDS/SARS include C1Qb, C5R1, CASP3, CASP9, CD14, CD68, FGF7, HLA-DRA, ICF1, IRF3, MALAT-1, MSR1, NFIL3, SLPI, USP33, CLC, GBP1 and TACI. As a result, we proposed to therapeutically target some of these genes with compounds such as ANPEP inhibitors, SLPI and dexamethasone. Ultimately, this study may serve as a model for future, tissue-based analyses of fibroinflammatory conditions affecting the lung. (C) 2009 Elsevier B.V. All rights reserved.

Decreased respiratory system compliance on the sixth day of mechanical ventilation is a predictor of death in patients with established acute lung injury

Background: Multiple studies have identified single variables or composite scores that help risk stratify patients at the time of acute lung injury (ALI) diagnosis. However, few studies have addressed the important question of how changes in pulmonary physiologic variables might predict mortality in patients during the subacute or chronic phases of ALI. We studied pulmonary physiologic variables, including respiratory system compliance, P/F ratio and oxygenation index, in a cohort of patients with ALI who survived more than 6 days of mechanical ventilation to see if changes in these variables were predictive of death and whether they are informative about the pathophysiology of subacute ALI.

Improved detection of acute myocardial infarction in patients with chest pain and significant left main stem coronary stenosis.

Background: Non-invasive diagnosis of acute myocardial infarction (AMI) associated with significant left main stem (LMS) stenosis remains challenging.

Methods: Consecutive patients presenting with acute ischaemic-type chest pain from 2000 to 2010 were analysed. Entry criteria: 12-lead ECG and Body Surface Potential Map (BSPM) at presentation, cardiac troponin T (cTnT) =12?h and coronary angiography during admission. cTnT =0.03?µg/l defined AMI. ECG abnormalities assessed: STEMI by Minnesota criteria; ST elevation (STE) aVR =0.5?mm; ST depression (STD) =0.5?mm in =2 contiguous leads (CL); T-wave inversion (TWI) =1?mm in =2 CL. BSPM STE was =2?mm in anterior, =1?mm in lateral, inferior, right ventricular or high right anterior and =0.5?mm in posterior territories. Significant LMS stenosis was =70%.

Results: Enrolled were 2810 patients (aged 60?±?12 years; 71% male). Of these, 116 (4.1%) had significant LMS stenosis with AMI occurring in 92 (79%). STEMI by Minnesota criteria occurred in 13 (11%) (sensitivity 12%, specificity 92%), STE in lead aVR in 23 (20%) (sensitivity 23%, specificity 92%), TWI in 38 (33%) (sensitivity 34%, specificity 71%) and STD in 51 (44%) (sensitivity 49%, specificity 75%). BSPM STE occurred in 85 (73%): sensitivity 88%, specificity 83%, positive predictive value 95% and negative predictive value 65%. Of those with AMI, 74% had STE in either the high right anterior or right ventricular territories not identified by the 12-lead ECG. C-Statistic for AMI diagnosis using BSPM STE was 0.800 (P?<?0.001).

Conclusion: In patients with significant LMS stenosis presenting with chest pain, BSPM STE has improved sensitivity (88%), with specificity 83%, over 12-lead ECG in the diagnosis of AMI.