Citations

Context. —Patients with pneumothorax occasionally require limited lung resections to control persistent air leaks. In some patients, especially smokers, histopathologic findings suggest that a ruptured bulla or bleb caused the pneumothorax. Other patients only exhibit histopathologic changes related to the physical trauma of acute, and likely occult recurrent, peripheral lung injury in the setting of “spontaneous,” or idiopathic, lung rupture. Sometimes, pneumothorax occurs secondary to an underlying localized or diffuse parenchymal lung disease. A comprehensive description of the morphologic findings that may be seen in these specimens will help the surgical pathologist distinguish patients with more common and indolent occurrences of pneumothorax from those requiring additional workup or treatment. Objective. —To develop a diagnostic approach for surgical pathologists encountering lung specimens obtained in the context of pneumothorax repair. Data Sources. —Literature review and consultation experience of the authors. Conclusions. —Two general categories of histopathologic changes can be identified: (1) nonspecific changes, reflecting the lung's acute and chronic response to localized injury, and (2) changes suggesting an underlying lung disease that may have played an etiologic role in the development of pneumothorax. The latter changes are important to recognize because they may require additional workup or treatment of clinically occult lung disease. Difficulty arises when nonspecific histopathologic changes overlap with those of an underlying lung disease. Awareness of these diagnostic challenges and pitfalls, together with clinicoradiographic correlation, is essential in these situations and will help guide the surgical pathologist toward an accurate diagnosis and the appropriate management of clinically occult disease.

ABSTRACT Intron-containing mRNAs are subject to restricted nuclear export in higher eukaryotes. Retroviral replication requires the nucleocytoplasmic transport of both spliced and unspliced RNA transcripts, and RNA export mechanisms of gammaretroviruses are poorly characterized. Here, we report the involvement of the nuclear export receptor NXF1/TAP in the nuclear export of gammaretroviral RNA transcripts. We identified a conserved cis -acting element in the pol gene of gammaretroviruses, including murine leukemia virus (MLV) and xenotropic murine leukemia virus (XMRV), named the CAE (cytoplasmic accumulation element). The CAE enhanced the cytoplasmic accumulation of viral RNA transcripts and the expression of viral proteins without significantly affecting the stability, splicing, or translation efficiency of the transcripts. Insertion of the CAE sequence also facilitated Rev-independent HIV Gag expression. We found that the CAE sequence interacted with NXF1, whereas disruption of NXF1 ablated CAE function. Thus, the CAE sequence mediates the cytoplasmic accumulation of gammaretroviral transcripts in an NXF1-dependent manner. Disruption of NXF1 expression impaired cytoplasmic accumulations of both spliced and unspliced RNA transcripts of XMRV and MLV, resulting in their nuclear retention or degradation. Thus, our results demonstrate that gammaretroviruses use NXF1 for the cytoplasmic accumulation of both spliced and nonspliced viral RNA transcripts. IMPORTANCE Murine leukemia virus (MLV) has been studied as one of the classic models of retrovirology. Although unspliced host messenger RNAs are rarely exported from the nucleus, MLV actively exports unspliced viral RNAs to the cytoplasm. Despite extensive studies, how MLV achieves this difficult task has remained a mystery. Here, we have studied the RNA export mechanism of MLV and found that (i) the genome contains a sequence which supports the efficient nuclear export of viral RNAs, (ii) the cellular factor NXF1 is involved in the nuclear export of both spliced and unspliced viral RNAs, and, finally, (iii) depletion of NXF1 results in nuclear retention or degradation of viral RNAs. Our study provides a novel insight into MLV nuclear export.

ABSTRACTIntroduction: The Valsalva maneuver (VM) is used widely to quantify the sensitivity of the vagal baroreflex loop (vagal baroreflex sensitivity, BRS_v), but most studies have focused on the heart rate (HR) response to blood pressure (BP) decrement (BRS_v↓), even though the subsequent response to an increment in BP after the VM (BRS_v↑) is important and different. Methods: We evaluated recordings of HR and BP in 187 normal subjects during the VM and determined both BRS_v↑, as determined by relating HR to the BP increase after phase III and BRS_v↓. Results: BRS_v↑ was related inversely to age. In addition, BRS_v↓, age, and magnitude of phase IV were independent predictors of BRS_v↑ in a multivariate model, accounting for 47% of the variance of BRS_v↑. Conclusions: The results indicate that both BRS_v↑ and BRS_v↓ become blunted with increasing age and that these indices relate to each other. Muscle Nerve 50: 535–540, 2014

Mutations in the electrogenic Na+/HCO3−cotransporter (NBCe1) that cause proximal renal tubular acidosis (pRTA), glaucoma, and cataracts in patients are recessive. Parents and siblings of these affected individuals seem asymptomatic although their tissues should make some mutant NBCe1 protein. Biochemical studies with AE1 and NBCe1 indicate that both, and probably all, Slc4 members form dimers. However, the physiologic implications of dimerization have not yet been fully explored. Here, human NBCe1A dimerization is demonstrated by biomolecular fluorescence complementation (BiFC). An enhanced yellow fluorescent protein (EYFP) fragment (1–158, EYFPN) or (159–238, EYFPC) was fused to the NH2or COOH terminus of NBCe1A and mix-and-matched expressed in Xenopus oocyte. The EYFP fluorescent signal was observed only when both EYFP fragments are fused to the NH2terminus of NBCe1A (EYFPN-N-NBCe1A w/ EYFPC-N-NBCe1A), and the electrophysiology data demonstrated this EYFP-NBCe1A coexpressed pair have wild-type transport function. These data suggest NBCe1A forms dimers and that NH2termini from the two monomers are in close proximity, likely pair up, to form a functional unit. To explore the physiologic significance of NBCe1 dimerization, we chose two severe NBCe1 mutations (6.6 and 20% wild-type function individually): S427L (naturally occurring) and E91R (for NH2-terminal structure studies). When we coexpressed S427L and E91R, we measured 50% wild-type function, which can only occur if the S427L-E91R heterodimer is the functional unit. We hypothesize that the dominant negative effect of heterozygous NBCe1 carrier should be obvious if the mutated residues are structurally crucial to the dimer formation. The S427L-E91R heterodimer complex allows the monomers to structurally complement each other resulting in a dimer with wild-type like function.

The newly proposed International Association for the Study of Lung Cancer, American Thoracic Society, and European Respiratory Society (IASLC/ATS/ERS) classification of lung adenocarcinoma has emphasized the prognostic significance of histological subtyping. In this study, 2 surgical pathologists reevaluated 49 consecutive cases of invasive primary pulmonary adenocarcinomas; histological subtyping was performed according to the IASLC/ATS/ERS classification. The 2 reviewers agreed on the predominant pattern in 23 out of 32 independently reviewed cases (71.9%, k = 0.628, 95% confidence interval = 0.442-0.815). Postconsensus, a complex glandular pattern consisting of fused, closely packed glands and cribriform architecture was identified in 9 of 49 (18%) cases. This pattern has a strong association with lymphovascular invasion (78%; P = .0091), high mitotic activity (89%), and higher tumor stage (78%). Frequent association of complex glandular pattern with poor prognostic factors and its overlap with acinar pattern warrant a more detailed description of this pattern in the classification system and a large-scale study to evaluate its prognostic significance.

Flow diversion treatment of cerebral aneurysms has increasingly been considered, especially for large complex aneurysms with wide necks that are difficult to treat with coils of by clipping. However, the relationship between the hemodynamic environment created immediately after implantation of flow diverters (FD) and the subsequent aneurysm occlusion is poorly understood [1].

Identifying tobacco use status is essential to address use and provide resources to help patients quit. Being able to collect this information in an electronic format will become increasingly important, as the Centers for Medicare and Medicaid Services has included the assessment of tobacco use as part of its Stage 1 Meaningful Use criteria. The objective was to compare the accuracy of online vs. paper assessment methods to ascertain cigarette smoking status using a face-to-face structured interview as the gold standard. This was a retrospective analysis of a stratified opportunity sample of consecutive patients, reporting in 2010 for a periodic health evaluation, who completed either a scannable paper-based form or an online questionnaire and underwent a standardized rooming interview. Compared with face-to-face structured interview, the overall observed agreement and kappa coefficient for both methods combined (paper and online) were 97.7% and 0.69 (95% confidence interval (CI) 0.51–0.86) . For the online form they were 97.4% and 0.61 (95% CI 0.33–0.90), and for the paper form they were 97.9% and 0.75 (95% CI 0.54–0.96). There was no statistically significant difference in agreement between the online and paper-based methods ( P =0.76) compared with a face-to-face structured interview. Online assessment of tobacco use status is as accurate as a paper questionnaire, and both methods have greater than 97% observed agreement with a face-to-face structured interview. The use of online assessment of tobacco use status has several advantages and more widespread use should be explored. ( Population Health Management 2014;17:185–189)

Endovascular coiling is the most common treatment for cerebral aneurysms. The treatment consists of deploying coils of different shapes and sizes into the aneurysm with the intent of reducing blood flow therein. While the treatment has been shown to be more effective than conventional surgical methods, it is successful in only 50–80% of cases, depending on the type of aneurysm [1]. Treatment success has been correlated with favorable post-treatment hemodynamics [2]. Understanding of the effects of coils on post-treatment hemodynamics is limited, however, due to limited in-vivo and in-vitro flow measurement techniques. Previous computational studies have also suffered from drastic assumptions about coil geometry.