Heterologous expression from the human D-Loop in organello

We report the expression of a linear reporter construct in isolated human mitochondria. The reporter construct contained the entire human D-Loop with adjacent tRNA (MTT) genes (mt.15956-647), the human ND1 gene with an in frame GFP gene and adjacent endogenous MTT genes and heterologous rat MTT genes. Natural competence of isolated human mitochondria of HepG2 cells was used to import reporter constructs. The import efficiency of various fluorescently labelled PCR-generated import substrates in the range of 250bp up to 3.5kb was assessed by quantitative PCR and evaluated by confocal microscopy. Heterologous expression of the imported construct was confirmed at RNA level by a circular RNA (cRNA)-RT-PCR assay for the expression of tRNAs and by in organello [α-(32)P]-UTP labelling and subsequent hybridisation to reporter-specific sequences for monitoring mRNA expression. Heterologous expression of rat mitochondrial tRNA(Leu(UUR)) (rMT-TL1) was confirmed by co-/post-transcriptional trinucleotide (CCA) addition. Interestingly, the rat-specific MT-TL1 was correctly processed in isolated human mitochondria at the 3' end, but showed an aberrant 5' end processing. Correct 3' end processing of the heterologous expressed mitochondrial rat tRNA(Ser2) (MT-TS2) was detected. These findings demonstrate the feasibility of genetic manipulation of human mitochondria, providing a tool for characterisation of cis-acting elements of the human mitochondrial genome and for the study of human mitochondrial tRNA processing in organello.

The role of inducible nitric oxide synthase for interstitial remodeling of alveolar septa in surfactant protein D-deficient mice

Surfactant protein D (SP-D) modulates the lung's immune system. Its absence leads to NOS2-independent alveolar lipoproteinosis and NOS2-dependent chronic inflammation, which is critical for early emphysematous remodeling. With aging, SP-D knockout mice develop an additional interstitial fibrotic component. We hypothesize that this age-related interstitial septal wall remodeling is mediated by NOS2. Using invasive pulmonary function testing such as the forced oscillation technique and quasistatic pressure-volume perturbation and design-based stereology, we compared 29-wk-old SP-D knockout (Sftpd(-/-)) mice, SP-D/NOS2 double-knockout (DiNOS) mice, and wild-type mice (WT). Structural changes, including alveolar epithelial surface area, distribution of septal wall thickness, and volumes of septal wall components (alveolar epithelium, interstitial tissue, and endothelium) were quantified. Twenty-nine-week-old Sftpd(-/-) mice had preserved lung mechanics at the organ level, whereas elastance was increased in DiNOS. Airspace enlargement and loss of surface area of alveolar epithelium coexist with increased septal wall thickness in Sftpd(-/-) mice. These changes were reduced in DiNOS, and compared with Sftpd(-/-) mice a decrease in volumes of interstitial tissue and alveolar epithelium was found. To understand the effects of lung pathology on measured lung mechanics, structural data were used to inform a computational model, simulating lung mechanics as a function of airspace derecruitment, septal wall destruction (loss of surface area), and septal wall thickening. In conclusion, NOS2 mediates remodeling of septal walls, resulting in deposition of interstitial tissue in Sftpd(-/-). Forward modeling linking structure and lung mechanics describes the complex mechanical properties by parenchymatous destruction (emphysema), interstitial remodeling (septal wall thickening), and altered recruitability of acinar airspaces.

Survival of gastrointestinal and stromal tumor patients at UT M.D. Anderson Cancer Center

Objective. Gastrointestinal Stromal Tumors (GISTs) are rare mesenchymal tumors of the gastrointestinal (GI) tract with spindled cell, epithelioid, or occasionally pleomorphic morphology. The primary objective of this paper is to describe the demographic and clinical characteristics and survival among GIST patients registered at the University of Texas M.D. Anderson Cancer Center (MDACC). ^ Methods. This cohort study includes 783 consecutive patients diagnosed with GIST from 1995 to 2007. Demographic, clinical and survival information were obtained from the MDACC cancer registry. ^ Statistical Analysis. Kaplan-Meier survival curves, univariate and multivariate Cox proportional hazards analysis were conducted to estimate survival and identify prognostic clinical factors associated with survival. Results. The age at diagnosis of MDACC GIST cases ranged from 17 to 91 with a mean of 57 years and a male-to-female ratio of 1.3:1. The racial distribution was whites 77%, African-Americans 9.5%, Hispanics 9.3% and other races 4.2%. Fifty per cent of the GISTs arose from stomach, 35% small intestine, 7% retroperitoneal space, 6% colorectal and 2% were omentum and mesentery. About half of the tumors were less than 10 cm in size. Fifty eight per cent of the tumors were localized whereas 36% were metastatic. MDACC GIST patients were generally comparable to SEER patients, but, on the average, were 7 years younger than SEER patients and were predominantly whites. ^ Stratification of 783 GIST cases by year of diagnosis based on the introduction of imatinib treatment in 2000 revealed that 60% of the GIST cases were first diagnosed between 2000 and 2007 whereas, 40% were first diagnosed between 1995 and 1999. There was a significant difference between the two cohorts in the distribution of race, GIST symptom, tumor size, tumor site, and stage of the tumor at diagnosis. The 1- and 5-year survival was 93% and 59% in the 1995–2007 cohort. Multivariate Cox regression analysis identified age at diagnosis (p<0.001), female sex (p=0.047), tumor size (p=0.07), multiple cancers (p=0.002), and GIST diagnosed between 2000 and 2007 (p<0.001) were significantly associated with survival. Approximately, 58% of the cases were treated with imatinib whereas 42% did not receive imatinib in 2000–2005 cohort. There was a significant difference in survival between imatinib and non-imatinib groups and in the distribution of tumor size categories, stage of the tumor at diagnosis and cancers before the diagnosis of GIST. The 1- and 5-year survival for imatinib patients was 99% and 73% and was 91% and 63% for non-imatinib patients. Multivariate Cox regression analysis of the 2000–2007 cohort identified, age at diagnosis and tumor stage as possible prognostic factors associated with survival.^

(Reseña sobre) Vicente Blasco Ibáñez: An Annotated Bibliography 1975-2002, de Christopher L. Anderson y Paul C. Smith

Fil: Contreras, María de los Angeles. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

(Reseña sobre) Vicente Blasco Ibáñez: An Annotated Bibliography 1975-2002, de Christopher L. Anderson y Paul C. Smith

Fil: Contreras, María de los Angeles. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.