Haemodynamic effects of patent foramen ovale and atrial septal defect closure: a comparison during percutaneous shunt closure

Objectives: We investigated the haemodynamic effect of percutaneous closure of an intra‐atrial shunt, using non‐invasive finger pressure measurements. Background: Percutaneous closure of both patent foramen ovale (PFO) and atrial septal defect (ASD) is widely practised. Currently no data are available on short‐term haemodynamic changes induced by closure. Methods: Twenty‐five consecutive patients (mean age 49 ± 17 years, 10 men) who underwent a percutaneous closure of a PFO (n = 15) or ASD (n = 10) were included in this study. During the procedure blood pressure and heart rate (HR) were monitored continuously with a Finometer^®. Changes in systolic, mean, and diastolic pressure, stroke volume (SV), cardiac output (CO) and total peripheral resistance (TPR) were computed from the pressure registrations using Modelflow^® methodology. Results: Baseline characteristics were similar for the PFO and ASD patients. After PFO closure none of the haemodynamic parameters changed significantly. After ASD closure the systolic, mean, and diastolic pressures increased 7·1 ± 5·4 (P = 0·003), 3·8 ± 3·5 (P = 0·007) and 2·0 ± 3·0 mmHg (P = ns) respectively. HR decreased 5·1 ± 5·3 beats per minute (P = 0·01). SV, CO and TPR increased 8·5 ± 6·4 ml (13·5%; P = 0·002), 0·21 ± 0·45 l min^?1 (5·6%; P = ns) and 0·02 ± 0·14 dynes (4·1%; P = ns) respectively. The changes in SV differ between the PFO and ASD patients (P = 0·009). Conclusions: Using non‐invasive finger pressure measurements, we found that SV, mean and systolic blood pressure increased immediately after percutaneous closure of an ASD in adults, whereas the percutaneous PFO closure had no effect on haemodynamic characteristics.     

Percutaneous cardiac recirculation-mediated gene transfer of an inhibitory phospholamban peptide reverses advanced heart failure in large animals.

OBJECTIVES: The purpose of this study was to develop a clinically applicable high-efficiency percutaneous means of therapeutic gene delivery to the failing heart. BACKGROUND: Substantial advances in the understanding of the cellular and molecular basis of heart failure (HF) have recently fostered interest in the potential utility of gene and cell therapy as novel therapeutic approaches. However, successful clinical translation is currently limited by the lack of safe, efficient, and selective delivery systems. METHODS: We developed a novel percutaneous closed-loop recirculatory system that provides homogeneous myocardial delivery for gene transfer in the failing large animal heart. After 4 weeks' rapid pacing in adult sheep to induce HF, the animals were randomly allocated to receive either adenovirus expressing a pseudophosphorylated mutant (AdS16E) of phospholamban (PLN) or Ad-beta-galactosidase (AdLacZ). RESULTS: Two weeks after gene delivery, in the presence of continued pacing, left ventricular (LV) ejection fraction had significantly improved in the AdS16E-treated animals (27 +/- 3% to 50 +/- 4%; p < 0.001), whereas a further decline occurred in the AdLacZ group (34 +/- 4% to 27 +/- 3%; p < 0.05). In conjunction, AdS16E delivery resulted in significant reductions in LV filling pressures and end-diastolic diameter (both p < 0.05). In conjunction, AdS16E-treated animals showed significant improvement in the expression of PLN and Ca2+-adenosine triphosphatase activity. In separate animals, recirculating AdLacZ delivery was shown to achieve superior myocardial gene expression in contrast to intracoronary delivery and was associated with lower systemic expression. CONCLUSIONS: We report the development of a novel closed-loop system for cardiac gene therapy. Using this approach delivery of AdS16E reversed HF progression in a large animal HF model.     

An overview of three different approaches to the interpretation of qualitative data. Part 1: Theoretical issues

In this paper, the first of two, Helena Priest, Paula Roberts and Leslie Woods discuss the essential features and methods inherent within three approaches to the interpretation of qualitative data. An overview of three methodologies commonly used in nursing and healthcare research is presented: grounded theory, qualitative content analysis and narrative analysis. The paper considers the philosophical bases of the three methods and the principles inherent within each analytical approach. Key stages and steps are presented and described.     

Skeletal muscle mRNA levels for cathepsin B, but not components of the ubiquitin-proteasome pathway, are increased in patients with lung cancer referred for thoracotomy

Muscle wasting is a common and prominent feature of advanced cancer, including lung cancer. Evidence from animal experiments suggests that accelerated proteolysis via the ubiquitin--proteasome pathway is the primary cause of cancer-related cachexia. However, there are few data on the role of this pathway in determining muscle wasting in human cancer. The present study was designed to measure whether skeletal muscle gene expression of components of the ubiquitin-proteasome pathway and/or the lysosomal proteolytic pathway was increased in patients with early lung cancer. A total of 36 patients with lung cancer referred for curative resection and 10 control subjects had biopsies of latissimus dorsi muscle taken at operation. mRNA levels of four components of the ubiquitin-proteasome pathway, i.e. polyubiquitin, C2 alpha proteasome subunit, 14 kDa ubiquitin-carrier protein and ubiquitin-activating protein, and of two lysosomal proteolytic enzymes, i.e. cathepsin B and cathepsin D, were measured using quantitative Northern blotting. mRNA levels for cathepsin B, but not for components of the ubiquitin--proteasome pathway, were higher in patients with cancer compared with controls (P=0.01). Among lung cancer patients, cathepsin B mRNA levels correlated with fat-free mass index (r = -0.57, P=0.003) and tumour stage (r(s)=0.45, P=0.03), and were higher in smokers (P=0.04). Thus gene expression of the lysosomal protease cathepsin B is increased in the skeletal muscle of patients with early lung cancer, and the strong inverse relationship with fat-free mass suggests that cathepsin B may have a role in inducing muscle wasting in the early stages of lung cancer.     

Performance characteristics of an automated high-sensitivity C-reactive protein assay on the Dimension RXL analyzer

BACKGROUND: C-reactive protein (CRP) is a nonspecific marker of inflammation that can be used as a marker for atherosclerotic risk. This application requires increased precision at low CRP concentrations compared to traditional assays. METHODS: The Dimension RXL is an automated chemistry analyzer for central laboratory use. The limit of detection, limit of quantification, linearity and imprecision of a high-sensitivity CRP assay developed for it were assessed. Method comparison studies were performed using samples both inside and outside the reference interval. The presence of a prozone effect was also evaluated. RESULTS: The limit of detection was 0.7 mg/l. The method was linear from 2 to 60 mg/l and from 1 to 60 mg/l using systematic error limits of 10% and 20%, respectively. The total imprecision was <10% for CRP concentrations above 1.5 mg/l. No prozone effect was seen at a CRP concentration of 450 mg/l, the highest concentration tested. Using samples from 212 apparently healthy adults, the Dimension RXL method demonstrated good concordance with the BN II high-sensitivity CRP method for samples in the highest quartile. It also compared well using samples with elevated CRP concentrations. CONCLUSIONS: The Dimension RXL high-sensitivity CRP method may be adequate for atherosclerotic risk prediction in clinical practice if accurate and precise measurement is only required for the highest quartile. However, the total error of this method for CRP concentrations <3 mg/l appears too large for accurate assignment to lower risk groups.     

Sustained localized expression of ligand for the activating NKG2D receptor impairs natural cytotoxicity in vivo and reduces tumor immunosurveillance

Upregulation of the inducible gene products MICA (human) and Rae-1 (mouse) may promote tumor surveillance and autoimmunity by engaging the activating receptor NKG2D on natural killer (NK) cells and T cells. Nevertheless, sustained expression of MICA by tumors can also elicit NKG2D downregulation, perhaps indicating 'immunoevasion'. Investigating this paradox, we report here that constitutive Rae-1epsilon transgene expression in normal epithelium elicited local and systemic NKG2D downregulation, generalized but reversible defects in NK cell-mediated cytotoxicity and mild CD8(+) T cell defects. The extent of NKG2D downregulation correlated well with the incidence and progression of cutaneous carcinogenesis, emphasizing the utility of NKG2D as a marker of tumor resistance. Thus, NKG2D engagement is a natural mediator of immunosurveillance, which can be compromised by locally sustained ligand expression but potentially restored by innate immune activation.     

Arterial endothelial function in a porcine model of early stage atherosclerotic vascular disease

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the United States and is projected to become the leading cause of mortality in the world. Atherosclerosis is the most important single factor contributing to this disease burden. In this study, we characterize relationships between endothelial dysfunction and vascular disease in an animal model of diet-induced, early-stage atherosclerotic vascular disease. We tested the hypothesis that hypercholesterolaemia induces vascular disease and impairs endothelium-dependent relaxation (EDR) in conduit arteries of adult male Yucatan pigs. Pigs were fed a normal fat (NF) or high fat cholesterol (HFC) diet for 20-24 weeks. Results indicate that, while the HFC diet did not alter EDR in femoral or brachial arteries, EDR was significantly decreased in both carotid and coronary arteries. Sudanophilic fatty streaks were significantly present in the abdominal aorta and common carotid artery. Histopathology revealed increased intima-media thickness (IMT) and foam cell accumulation in Stary Stage I-III lesions in the abdominal aorta, common carotid artery and femoral arteries. In the coronary arteries, the accumulation of foam cells in Stary Stage I and II lesions resulted in a trend for increased IMT. There was no evidence of vascular disease in the brachial arteries. These results indicate that early stages of CVD (Stary Stage I-III) precede decreases in EDR induced by HFC diet, because femoral arteries exhibited foam cell accumulation and an increased IMT but no change in endothelial function.     

Granulocyte colony-stimulating factor prior to nonmyeloablative irradiation decreases murine host hematopoietic stem cell function and increases engraftment of donor marrow cells

The use of nonmyeloablative conditioning prior to bone marrow transplantation is an important component of transplantation-based therapies for nonmalignant blood diseases. In this study, treatment of recipient mice with granulocyte colony-stimulating factor (G-CSF) prior to low-dose total body irradiation (LD-TBI) enhanced long-term engraftment of freshly isolated congenic marrow 1.5- to 2-fold more than treatment with LD-TBI alone. This combined regimen was also evaluated in a mouse model of X-linked chronic granulomatous disease (X-CGD), where neutrophils have a defective NADPH oxidase due to genetic deletion of the gp91(phox) subunit. Long-term engraftment of male X-CGD bone marrow cells cultured ex vivo for retroviral transduction of gp91(phox) was enhanced by approximately 40% when female X-CGD recipients were pretreated with G-CSF prior to 300 cGy. These data confirm that sequential treatment with G-CSF and LD-TBI prior to transplantation increases long-term engraftment of donor marrow, and they extend this approach to transplantation of murine donor marrow cultured ex vivo for gene transfer. Additional studies showed that the administration of G-CSF prior to LD-TBI did not alter early homing of donor marrow cells. However, the combined regimen significantly decreased the content of long-term repopulating cells in recipient marrow compared with LD-TBI alone, as assessed in competitive assays, which may contribute to the enhanced engraftment of donor marrow cells. Disclosure of potential conflicts of interest is found at the end of this article.