Correcting for Selection Bias and Missing Response in Regression using Privileged Information

When estimating a regression model, we might have data where some labels are missing, or our data might be biased by a selection mechanism. When the response or selection mechanism is ignorable (i.e., independent of the response variable given the features) one can use off-the-shelf regression methods; in the nonignorable case one typically has to adjust for bias. We observe that privileged data (i.e. data that is only available during training) might render a nonignorable selection mechanism ignorable, and we refer to this scenario as Privilegedly Missing at Random (PMAR). We propose a novel imputation-based regression method, named repeated regression, that is suitable for PMAR. We also consider an importance weighted regression method, and a doubly robust combination of the two. The proposed methods are easy to implement with most popular out-of-the-box regression algorithms. We empirically assess the performance of the proposed methods with extensive simulated experiments and on a synthetically augmented real-world dataset. We conclude that repeated regression can appropriately correct for bias, and can have considerable advantage over weighted regression, especially when extrapolating to regions of the feature space where response is never observed

Phosphatidylethanolamine mediates insertion of the catalytic domain of leader peptidase in membranes

AbstractLeader peptidase is an integral membrane protein of E. coli and it catalyses the removal of most signal peptides from translocated precursor proteins. In this study it is shown that when the transmembrane anchors are removed in vivo, the remaining catalytic domain can bind to inner and outer membranes of E. coli. Furthermore, the purified catalytic domain binds to inner membrane vesicles and vesicles composed of purified inner membrane lipids with comparable efficiency. It is shown that the interaction is caused by penetration of a part of the catalytic domain between the lipids. Penetration is mediated by phosphatidylethanolamine, the most abundant lipid in E. coli, and does not seem to depend on electrostatic interactions. A hydrophobic segment around the catalytically important residue serine 90 is required for the interaction with membranes

Hubble Space Telescope Observations of NGC 6240: a Case Study of an Ultra-Luminous Infrared Galaxy with Obscured Activity

We present results from an HST study of the morphology and kinematics of NGC 6240. This merging galaxy with a double nucleus is one of the nearest and best-studied ultraluminous infrared galaxies. HST resolves both nuclei into seperate components. The distance between the northern and southern optical/near-infrared components is greater than that observed in radio and X-ray studies, arguing that even in K-band we may not be seeing all the way through the dust to the true nuclei. The ionized gas does not display rotation around either of the nuclei, or equilibrium motion in general. There is a strong velocity gradient between the nuclei, similar to what is seen in CO data. There is no such gradient in our stellar kinematics. The velocity dispersion of the gas is larger than expected for a cold disk. We also map and model the emission-line velocity field at an off-nuclear position where a steep velocity gradient was previously detected in ground-based data. Overall, the data indicate that line-of-sight projection effects, dust absorption, non-equilibrium merger dynamics, and the possible influence of a wind may be playing an important role in the observed kinematics. Chandra observations of hard X-rays have shown that both of the nuclei contain an Active Galactic Nucleus (AGN). The HST data show no clear sign of the two AGNs: neither continuum nor narrow-band imaging shows evidence for unresolved components in the nuclei, and there are no increased emission line widths or rapid rotation near the nuclei. This underscores the importance of X-ray data for identifying AGNs in highly dust-enshrouded environments.Comment: LaTeX, 32 pages, 9 figures, 2 tables, accepted for publication in The Astronomical Journal (Jan 2004). Paper with high-resolution (non-compressed) color figures in gzipped postscript format available at http://www.stsci.edu/~marel/psgzdir/ngc6240v11.ps.g

Low-dose cyclophosphamide synergizes with dendritic cell-based immunotherapy in antitumor activitys

Clinical immunotherapy trials like dendritic cell-based vaccinations are hampered by the tumor's offensive repertoire that suppresses the incoming effector cells. Regulatory T cells are instrumental in suppressing the function of cytotoxic T cells. We studied the effect of low-dose cyclophosphamide on the suppressive function of regulatory T cells and investigated if the success rate of dendritic cell immunotherapy could be improved. For this, mesothelioma tumor-bearing mice were treated with dendritic cell-based immunotherapy alone or in combination with low-dose of cyclophosphamide.

Diagnostic yield and accuracy in a tertiary referral syncope unit validating the ESC guideline on syncope:a prospective cohort study

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Triggering receptor expressed on myeloid cells (TREM)-2 Impairs host defense in experimental melioidosis

Triggering receptor expressed on myeloid cells (TREM) -1 and TREM-2 are key regulators of the inflammatory response that are involved in the clearance of invading pathogens. Melioidosis, caused by the "Tier 1" biothreat agent Burkholderia pseudomallei, is a common form of community-acquired sepsis in Southeast-Asia. TREM-1 has been suggested as a biomarker for sepsis and melioidosis. We aimed to characterize the expression and function of TREM-1 and TREM-2 in melioidosis.Wild-type, TREM-1/3 (Trem-1/3-/-) and TREM-2 (Trem-2-/-) deficient mice were intranasally infected with live B. pseudomallei and killed after 24, and/or 72 h for the harvesting of lungs, liver, spleen, and blood. Additionally, survival studies were performed. Cellular functions were further analyzed by stimulation and/or infection of isolated cells. TREM-1 and TREM-2 expression was increased both in the lung and liver of B. pseudomallei-infected mice. Strikingly, Trem-2-/-, but not Trem-1/3-/-, mice displayed a markedly improved host defense as reflected by a strong survival advantage together with decreased bacterial loads, less inflammation and reduced organ injury. Cellular responsiveness of TREM-2, but not TREM-1, deficient blood and bone-marrow derived macrophages (BMDM) was diminished upon exposure to B. pseudomallei. Phagocytosis and intracellular killing of B. pseudomallei by BMDM and alveolar macrophages were TREM-1 and TREM-2-independent.We found that TREM-2, and to a lesser extent TREM-1, plays a remarkable detrimental role in the host defense against a clinically relevant Gram-negative pathogen in mice: TREM-2 deficiency restricts the inflammatory response, thereby decreasing organ damage and mortality

Preoperative endoscopic biliary drainage by metal versus plastic stents for resectable perihilar cholangiocarcinoma

Background and Aims: Adequate preoperative biliary drainage (PBD) is recommended in most patients with resectable perihilar cholangiocarcinoma (pCCA). Most expert centers use endoscopic plastic stents rather than self-expandable metal stents (SEMSs). In the palliative setting, however, use of SEMSs has shown longer patency and superior survival. The aim of this retrospective study was to compare stent dysfunction of SEMSs versus plastic stents for PBD in resectable pCCA patients. Methods:In this multicenter international retrospective cohort study, patients with potentially resectable pCCAs who underwent initial endoscopic PBD from 2010 to 2020 were included. Stent failure was a composite end point of cholangitis or reintervention due to adverse events or insufficient PBD. Other adverse events, surgical outcomes, and survival were recorded. Propensity score matching (PSM) was performed on several baseline characteristics. Results: A total of 474 patients had successful stent placement, of whom 61 received SEMSs and 413 plastic stents. PSM (1:1) resulted in 2 groups of 59 patients each. Stent failure occurred significantly less in the SEMSs group (31% vs 64%; P &lt; .001). Besides less cholangitis after SEMSs placement (15% vs 31%; P = .012), other PBD-related adverse events did not differ. The number of patients undergoing surgical resection was not significantly different (46% vs 49%; P = .71). Complete intraoperative SEMSs removal was successful and without adverse events in all patients. Conclusions: Stent failure was lower in patients with SEMSs as PBD compared with plastic stents in patients with resectable pCCA. Removal during surgery was quite feasible. Surgical outcomes were similar.</p

30. 針刺麻酔に関する文献的ならびに基礎的研究(第519回千葉医学会例会 第8回佐藤外科例会)

<p>Cytokine response in lung homogenates, BALF and plasma of WT and <i>Trem-2</i>^<i>-/-</i> mice during experimental melioidosis.</p

A nationwide assessment of hepatocellular adenoma resection:Indications and pathological discordance

Hepatocellular adenomas (HCAs) are benign liver tumors associated with bleeding or malignant transformation. Data on the indication for surgery are scarce. We analyzed indications and outcome of patients operated for HCAs 50 mm (52%), suspicion of (pre)malignancy (28%), and (previous) bleeding (5.1%). No difference was observed in HCA-subtype distribution between small and large tumors. Ninety-six (43%) patients had a postoperative change in diagnosis. Independent risk factors for change in diagnosis were tumor size <50 mm (adjusted odds ratio [aOR], 3.4; p < 0.01), male sex (aOR, 3.7; p = 0.03), and lack of hepatobiliary contrast-enhanced magnetic resonance imaging (CE-MRI) (aOR, 1.8; p = 0.04). Resection for small (suspected) HCAs was mainly indicated by suspicion of (pre)malignancy, whereas for large (suspected) HCAs, tumor size was the most prevalent indication. Male sex, tumor size <50 mm, and lack of hepatobiliary CE-MRI were independent risk factors for postoperative change in tumor diagnosis