Chronic thromboembolic pulmonary hypertension.

The pulmonary hypertension (PH) and right heart dysfunction that results from chronic thromboembolic involvement of the pulmonary vascular bed is potentially curable with surgical endarterectomy. Over the past several decades, growing clinical experience has brought about increased recognition of this treatable form of PH. Moreover, advances in cardiothoracic surgical techniques have given an increasing number of patients with chronic thromboembolic PH (CTEPH) a surgical remedy with decreasing perioperative morbidity and mortality risks. The availability of pulmonary hypertensive-specific medical therapy for CTEPH patients with surgically inaccessible disease also has been a positive therapeutic advance over the past several years. However, despite this progress, chronic thromboembolic disease as a sequela of acute pulmonary emboli continues to be underappreciated. Furthermore, even if CTEPH has been appropriately diagnosed, misinterpretation of diagnostic information may lead to the inappropriate exclusion of patients from surgical consideration. This may result in the prescription of pulmonary hypertensive medical therapy in CTEPH patients with potentially surgically correctable disease. This difficulty arises from a lack of objective criteria as to what constitutes surgical chronic thromboembolic disease, which primarily is a result of the variability in surgical experience in specialty centers in the United States. Consequently, clinicians must be wary about using pulmonary hypertensive medications in CTEPH patients. Before prescription, it is important to exclude patients from surgical consideration by consulting a specialized center with expertise in this discipline.

Phosphoinositide3-kinase regulates actin polymerization during delayed phagocytosis of Helicobacter pylori.

We have shown previously that ulcerogenic (type I) strains of Helicobacter pylori (Hp) retard their entry into macrophages. However, the signaling pathways that regulate Hp phagocytosis are largely undefined. We show here that Hp strongly activated class IA phosphoinositide3-kinases (PI3Ks) in macrophages, coincident with phagocytosis, and endogenous p85 and active protein kinase Balpha accumulated on forming phagosomes. PI3K inhibitors, wortmannin and LY294002, inhibited phagocytosis of Hp in a dose-dependent manner, and blockade of engulfment correlated directly with loss of 3'-phosphoinositides in the membrane subjacent to attached bacteria. During uptake of large immunoglobulin G (IgG)-coated particles, PI3Ks regulate pseudopod extension and phagosome closure. In marked contrast, we show here that 3'-phosphoinositides regulated actin polymerization at sites of Hp uptake. Moreover, Hp and IgG beads activated distinct PI3K isoforms. Phagosomes containing IgG-coated particles accumulated 3'-phosphatase and tensin homologue deleted on chromosome 10 and Src homology 2 domain-containing inositol 5'-phosphatase, yet Hp phagosomes did not. Finally, rapid uptake of IgG-opsonized Hp or a less-virulent type II Hp was PI3K-independent. We conclude that Hp and IgG beads are ingested by distinct mechanisms and that PI3Ks regulate the actin cytoskeleton during slow phagocytosis of ulcerogenic Hp.

Effect of recording duration on the diagnostic accuracy of out-of-center sleep testing for obstructive sleep apnea.

STUDY OBJECTIVES: This study investigated the minimum recording time needed during out-of-center sleep testing (OCST) to accurately diagnose the presence and severity of obstructive sleep apnea (OSA). DESIGN AND SETTING: A retrospective analysis was conducted of OCSTs performed from October 2009 to May 2012 at the Mayo Clinic Center of Sleep Medicine using the portable Embletta™ system. PATIENTS OR PARTICIPANTS: Demographic information was collected for patients who underwent OCSTs during the study period, including presenting symptoms, examination findings, and comorbidities. INTERVENTION: Each study was divided into 60-, 120-, 180-, 240-, 300-, 360-, and 420-min intervals beginning at the recording start time to determine the respiratory event index (REI) for each of these time intervals. These interval values were then compared to the original REI derived from the total recording time (REITRT) by a paired t-test and concordance correlation coefficient (CCC). MEASUREMENTS AND RESULTS: There were significant differences between the REITRT and the REI from the 60-min (P < 0.0001), 120-min (0.0001), 180-min (0.003) and 240-min (0.006) intervals with a lack of concordance, suggesting these intervals are poor diagnostic correlates for the REITRT. REIs determined at 300, 360, and 420 min were not significantly different from the REITRT and had highly significant CCCs, 0.963, 0.987, and 0.995, respectively. CONCLUSIONS: The results suggest that at least 300 min recording time during out-of-center sleep testing is needed for accurate diagnosis of obstructive sleep apnea and determination of obstructive sleep apnea severity.

Chronic thromboembolic pulmonary hypertension in pediatric patients.

OBJECTIVE: Chronic thromboembolic pulmonary hypertension is a rare form of pulmonary hypertension that can lead to progressive right heart failure and death. Pulmonary thromboendarterectomy surgery is the treatment of choice resulting in significant improvements in functional status, cardiopulmonary hemodynamics, and survival. This study reports the largest case series of pediatric patients with chronic thromboembolic pulmonary hypertension who underwent pulmonary thromboendarterectomy surgery at one institution. PATIENT AND METHODS: The University of California, San Diego, chronic thromboembolic pulmonary hypertension database identified patients 18 years or younger at the time of pulmonary thromboendarterectomy surgery (n = 17). Medical charts were reviewed for hemodynamics, thromboembolic risk factors, and postoperative outcomes. RESULTS: Pulmonary thromboendarterectomy surgery in pediatric patients resulted in improved functional status and significantly improved cardiopulmonary hemodynamics: mean arterial pressure decreased from 45.5 mm Hg ± 20.7 to 27.3 ± 13.0 mm Hg (P = .00073), pulmonary vascular resistance decreased from 929 ± dynes · s · cm(-5) to 299 ± 307 dynes · s · cm(-5) (P = .0012), and cardiac output improved from 3.8 ± 1.1 L/min to 5.6 ± 1.6 L/min (P = .0061). There were no deaths during surgery or 30 days after surgery, and long-term survival (5+ years) was achieved in 87.5%. As compared to adults with chronic thromboembolic pulmonary hypertension, there was a higher rate of rethrombosis in pediatric patients (38% vs 1%-4%). CONCLUSIONS: This study demonstrates that pulmonary thromboendarterectomy surgery in pediatric patients with chronic thromboembolic pulmonary hypertension is well tolerated with improved postoperative hemodynamics, functional status, minimal postoperative complications, and low perioperative mortality, similar to that reported for adults with chronic thromboembolic pulmonary hypertension, with the notable exception being a higher rate of rethrombosis in pediatric patients.

Helicobacter pylori disrupts NADPH oxidase targeting in human neutrophils to induce extracellular superoxide release.

Helicobacter pylori (Hp) infection triggers a chronic influx of polymorphonuclear leukocyte neutrophils (PMNs) into the gastric mucosa. Although Hp reside in a neutrophil-rich environment, how these organisms evade phagocytic killing is largely unexplored. We now show that live Hp (strains 11637, 60190, DT61A, and 11916) are readily ingested by PMNs and induce a rapid and strong respiratory burst that is comparable to PMA. Relative to other particulate stimuli, Hp are more potent activators of PMNs than opsonized zymosan, Staphylococcus aureus, or Salmonella. Strikingly, biochemical and microscopic analyses demonstrate that Hp disrupt NADPH oxidase targeting such that superoxide anions are released into the extracellular milieu and do not accumulate inside Hp phagosomes. Specifically, nascent Hp phagosomes acquire flavocytochrome b558 but do not efficiently recruit or retain p47phox or p67phox. Superoxide release peaks at 16 min coincident with the appearance of assembled oxidase complexes in patches at the cell surface. Oxidant release is regulated by formalin-resistant and heat-sensitive bacterial surface factors distinct from urease and Hp(2-20). Following opsonization with fresh serum, Hp triggers a modest respiratory burst that is confined to the phagosome, and ingested bacteria are eliminated. We conclude that disruption of NADPH oxidase targeting allows unopsonized Hp to escape phagocytic killing, and our findings support the hypothesis that bacteria and PMNs act in concert to damage the gastric mucosa.