Obstructive Sleep Apnea An Emerging Risk Factor for Atherosclerosis

Obstructive sleep apnea (OSA) is independently associated with death from cardiovascular diseases, including myocardial infarction and stroke. Myocardial infarction and stroke are complications of atherosclerosis; therefore, over the last decade investigators have tried to unravel relationships between OSA and atherosclerosis. OSA may accelerate atherosclerosis by exacerbating key atherogenic risk factors. For instance, OSA is a recognized secondary cause of hypertension and may contribute to insulin resistance, diabetes, and dyslipidemia. In addition, clinical data and experimental evidence in animal models suggest that OSA can have direct proatherogenic effects inducing systemic inflammation, oxidative stress, vascular smooth cell activation, increased adhesion molecule expression, monocyte/lymphocyte activation, increased lipid loading in macrophages, lipid peroxidation, and endothelial dysfunction. Several cross-sectional studies have shown consistently that OSA is independently associated with surrogate markers of premature atherosclerosis, most of them in the carotid bed. Moreover, OSA treatment with continuous positive airway pressure may attenuate carotid atherosclerosis, as has been shown in a randomized clinical trial. This review provides an update on the role of OSA in atherogenesis and highlights future perspectives in this important research area. CHEST 2011; 140(2):534-542

Adipose tissue mesenchymal stem cell expansion in animal serum-free medium supplemented with autologous human platelet lysate

BACKGROUND: Mesenchymal stem cells (MSCs) have been considered for human regenerative therapy applications, and safe culture and expansion protocols are needed especially in the context of interspecies contamination. Human platelet lysate (PL) has been proposed as animal serum substitute during in vitro MSC expansion. In this work, a simplified and efficient method to obtain autologous PL to replace animal serum in cell culture applications is described. STUDY DESIGN AND METHODS: PL obtained by freezing and centrifugation procedures was tested as medium supplement for human adipose mesenchymal stem cell (hASC) culture. Differential proliferation, immunophenotypic changes, and differentiation under PL or fetal bovine serum (FBS) were assessed. RESULTS: In contrast to 10% FBS supplementation, cell population doubling time was significantly lower when hASCs were cultured with the same concentration of PL ( PL 22.9 +/- 1.5 hr vs. FBS 106.7 +/- 6.5 hr, t test, p < 0.05). Furthermore, hASCs maintained with 2.5% PL supplementation also showed satisfactory results. Immunophenotypic analysis revealed no differences between hASCs cultivated with PL or FBS supplementation and both cultures retained the potential to differentiate into adipose cells. These results demonstrate that autologous PL obtained from the same donor can be used as animal serum substitute in hASC culture. CONCLUSIONS: Taken together, evidence is provided that platelets provided by a single donor are sufficient to obtain PL for hASC propagation for clinical-scale applications mitigating the potential untoward side effects associated with the use of animal-derived reagents.

Predictive models for diagnosis of pleural effusions secondary to tuberculosis or cancer

Background and objective: Tuberculosis (TB) and cancer are two of the main causes of pleural effusions which frequently share similar clinical features and pleural fluid profiles. This study aimed to identify diagnostic models based on clinical and laboratory variables to differentiate tuberculous from malignant pleural effusions. Methods: A retrospective study of 403 patients (200 with TB; 203 with cancer) was undertaken. Univariate analysis was used to select the clinical variables relevant to the models composition. Variables beta coefficients were used to define a numerical score which presented a practical use. The performances of the most efficient models were tested in a sample of pleural exudates (64 new cases). Results: Two models are proposed for the diagnosis of effusions associated with each disease. For TB: (i) adenosine deaminase (ADA), globulins and the absence of malignant cells in the pleural fluid; and (ii) ADA, globulins and fluid appearance. For cancer: (i) patient age, fluid appearance, macrophage percentage and presence of atypical cells in the pleural fluid; and (ii) as for (i) excluding atypical cells. Application of the models to the 64 pleural effusions showed accuracy higher than 85% for all models. Conclusions: The proposed models were effective in suggesting pleural tuberculosis or cancer.

Preliminary findings from a new animal model for Peyronie`s disease involving extracorporeal shock waves

To develop an experimental model in rabbits to analyse the efficiency of extracorporeal shock wave therapy (ESWT) for Peyronie`s disease. We used 15 adult male rabbits divided into three equal groups. In group 1 (no penile ESWT) rabbits had three sessions of ESWT with 2000 shocks each (15 kV), but a rubber mat was placed between the shock head and rabbit to protect the penis; the rabbits were killed at 7 days after the last session of ESWT. In group 2 the rabbits had three sessions of ESWT using the same parameters, and were killed immediately after the last session to analyse the penis. In group 3 the rabbits had three sessions of ESWT as before but were killed at 7 days after the last session, and the penile tissue analysed macroscopically and histologically. The results showed clearly that the model was efficient, creating a similar situation to that when applying ESWT in the human penis. All of the rabbits in groups 2 and 3 had haematomas and diffuse petechiae after ESWT, and only four had urethral and penile bleeding. Almost all macroscopic changes disappeared after 48 h and only one rabbit in group 3 after 7 days had a haematoma on the dorsal penile surface. The histology (assessed using haematoxylin and eosin staining) of the cavernous body of the penis showed: unchanged histology in group 1; in group 2 there was a dilated and congested vascular space in the cavernous body, with interstitial extensive bleeding in the dermis; and in group 3 there was an increase in interstitial fibrous tissue in the cavernous septum, with deposition of collagen fibres and thickening of the tunica albuginea. The present model was efficient in producing tissue injury in the normal penis when treated with ESWT, suggesting that this promising model should be considered for use future studies of Peyronie`s disease.

Assessment of a New Experimental Model of Isolated Right Ventricular Failure

We assessed a new experimental model of isolated right ventricular (RV) failure, achieved by means of intramyocardial injection of ethanol. RV dysfunction was induced in 13 mongrel dogs via multiple injections of 96% ethanol (total dose 1 mL/kg), all over the inlet and trabecular RV free walls. Hemodynamic and metabolic parameters were evaluated at baseline, after ethanol injection, and on the 14th postoperative day (POD). Echocardiographic parameters were evaluated at baseline, on the sixth POD, and on the 13th POD. The animals were then euthanized for histopathological analysis of the hearts. There was a 15.4% mortality rate. We noticed a decrease in pulmonary blood flow right after RV failure (P = 0.0018), as well as during reoperation on the 14th POD (P = 0.002). The induced RV dysfunction caused an increase in venous lactate levels immediately after ethanol injection and on the 14th POD (P < 0.0003). The echocardiogram revealed a decrease in the RV ejection fraction on the sixth and 13th PODs (P = 0.0001). There was an increased RV end-diastolic volume on the sixth (P = 0.0001) and 13th PODs (P = 0.0084). The right ventricle showed a 74% +/- 0.06% transmural infarction area, with necrotic lesions aged 14 days. Intramyocardial ethanol injection has allowed the creation of a reproducible and inexpensive model of RV failure. The hemodynamic, metabolic, and echocardiographic parameters assessed at different protocol times are compatible with severe RV failure. This model may be useful in understanding the pathophysiology of isolated right-sided heart failure, as well as in the assessment of ventricular assist devices.

EFFECTS OF A POTENT PEROXYNITRITE DECOMPOSITION CATALYST IN MURINE MODELS OF ENDOTOXEMIA AND SEPSIS

Excessive free-radical production due to various bacterial components released during bacterial infection has been linked to cell death and tissue injury. Peroxynitrite is a highly reactive oxidant produced by the combination of nitric oxide (NO) and superoxide anion, which has been implicated in cell death and tissue injury in various forms of critical illness. Pharmacological decomposition of peroxynitrite may represent a potential therapeutic approach in diseases associated with the overproduction of NO and superoxide. In the present study, we tested the effect of a potent peroxynitrite decomposition catalyst in murine models of endotoxemia and sepsis. Mice were injected i.p. with LPS 40 mg/kg with or without FP15 [Fe(III) tetrakis-2-(N-triethylene glycol monomethyl ether) pyridyl porphyrin] (0.1, 0.3, 1, 3, or 10 mg/kg per hour). Mice were killed 12 h later, followed by the harvesting of samples from the lung, liver, and gut for malondialdehyde and myeloperoxidase measurements. In other subsets of animals, blood samples were obtained by cardiac puncture at 1.5, 4, and 8 h after LPS administration for cytokine (TNF-alpha, IL-1 beta, and IL-10), nitrite/nitrate, alanine aminotransferase, and blood urea nitrogen measurements. Endotoxemic animals showed an increase in survival from 25% to 80% at the FP15 doses of 0.3 and 1 mg/kg per hour. The same dose of FP15 had no effect on plasma levels of nitrite/nitrate. There was a reduction in liver and lung malondialdehyde in the endotoxemic animals pretreated with FP15, as well as in hepatic myeloperoxidase and biochemical markers of liver and kidney damage (alanine aminotransferase and blood urea nitrogen). In a bacterial model of sepsis induced by cecal ligation and puncture, FP15 treatment (0.3 mg/kg per day) significantly protected against mortality. The current data support the view that peroxynitrite is a critical factor mediating liver, gut, and lung injury in endotoxemia and septic shock: its pharmacological neutralization may be of therapeutic benefit.

Effects of Residual Oil Fly Ash (ROFA) in Mice with Chronic Allergic Pulmonary Inflammation

transition metals, which are involved in the pathological effects of PM. The objective of this study was to investigate the effects of intranasal administration of ROFA on pulmonary inflammation, pulmonary responsiveness, and excess mucus production in a mouse model of chronic pulmonary allergic inflammation. BALB/c mice received intraperitoneal injections of ovalbumin (OVA) solution (days 1 and 14). OVA challenges were performed on days 22, 24, 26, and 28. After the challenge, mice were intranasally instilled with ROFA. After forty-eight hours, pulmonary responsiveness was performed. Mice were sacrificed, and lungs were removed for morphometric analysis. OVA-exposed mice presented eosinophilia in the bronchovascular space (p < .001), increased pulmonary responsiveness (p < .001), and epithelial remodeling (p = .003). ROFA instillation increased pulmonary responsiveness (p = .004) and decreased the area of ciliated cells in the airway epithelium (p = .006). The combined ROFA instillation and OVA exposure induced a further increase in values of pulmonary responsiveness (p = .043) and a decrease in the number of ciliated cells in the airway epithelium (p = .017). PM exposure results in pulmonary effects that are more intense in mice with chronic allergic pulmonary inflammation.

Nonhuman primate models and the failure of the Merck HIV-1 vaccine in humans

The adenovirus type 5 (Ad5)-based vaccine developed by Merck failed to either prevent HIV-1 infection or suppress viral load in subsequently infected subjects in the STEP human Phase 2b efficacy trial. Analogous vaccines had previously also failed in the simian immunodeficiency virus (SIV) challenge-rhesus macaque model. In contrast, vaccine protection studies that used challenge with a chimeric simian-human immunodeficiency virus (SHIV89.6P) in macaques did not predict the human trial results. Ad5 vector -based vaccines did not protect macaques from infection after SHIV89.6P challenge but did cause a substantial reduction in viral load and a preservation of CD4(+) T cell counts after infection, findings that were not reproduced in the human trials. Although the SIV challenge model is incompletely validated, we propose that its expanded use can help facilitate the prioritization of candidate HIV-1 vaccines, ensuring that resources are focused on the most promising candidates. Vaccine designers must now develop T cell vaccine strategies that reduce viral load after heterologous challenge.

Higgs pair production at the LHC in models with universal extra dimensions

In this Letter we study the process of gluon fusion into a pair of Higgs bosons in a model with one universal extra dimension. We find that the contributions from the extra top quark Kaluza-Klem excitations lead to a Higgs pair production cross section at the LHC that can be significantly altered compared to the Standard Model value for small values of the compactification scale. (C) 2007 Elsevier B.V. All rights reserved.

Gasless fetoscopy: A new approach to endoscopic closure of a lumbar skin defect in fetal sheep

Objective: To develop a new endoscopic approach to the correction of a myelomeningocele-like defect in fetal sheep. Methods: The fetuses of 9 pregnant ewes, with an average gestational age of 115 days, were subjected to a 3.0 x 2.0 cm removal of the skin over the lumbar spine, performed through hysterotomy. The uterus was closed, and three 5-mm endoscopic cannulas, without valve mechanisms, were inserted. In the pilot phase (2 animals), we initially worked exclusively in the amniotic fluid space. In the study phase, we partially withdrew the fetus from the amniotic fluid to completely expose its back. By simply allowing air to enter the amniotic cavity (without gas injection), a working space was created using a uterine lift device. The skin around the defect was dissected, and a biosynthetic cellulose material was applied to cover the area. A continuous suture of the skin was performed to completely hide the material. Results: The combined air/fluid space allowed the skin to be successfully closed in 6 out of 7 cases in the study phase. All fetuses were alive at the end of the procedures. Time to complete the endoscopic part of the procedure fell from 3 to 1 h by the end of this series. Premature birth occurred in 2 of the 4 cases allowed to continue with the pregnancy. Conclusion: A new gasless fetoscopic surgery technique was developed as an alternative to current techniques used for fetal endoscopic surgery. Copyright (C) 2008 S. Karger AG, Basel.