bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Cauchy radius for scalar and matrix polynomials
Authors: Melman A.
Published: May 2017

We improve the Cauchy radius of both scalar and matrix polynomials, which is an upper bound on the moduli of the zeros and eigenvalues, respectively, by using appropriate polynomial multipliers.
NEK7 is required for G1 progression and procentriole formation
Authors: Gupta Akshari , Tsuchiya Yuki , Ohta Midori , Shiratsuchi Gen , Kitagawa Daiju
Published: May 2017

The decision to commit to the cell cycle is made during G1 through the concerted action of various cyclin–CDK complexes. Not only DNA replication, but also centriole duplication is initiated as cells enter the S-phase. The NIMA-related kinase NEK7 is one of many factors required for proper centriole duplication, as well as for timely cell cycle progression. However, its specific roles in these events are poorly understood. In this study, we find that depletion of NEK7 inhibits progression through the G1 phase in human U2OS cells via down-regulation of various cyclins and CDKs and also inhibits the earliest stages of procentriole formation. Depletion of NEK7 also induces formation of primary cilia in human RPE1 cells, suggesting that NEK7 acts at least before the restriction point during G1. G1-arrested cells in the absence of NEK7 exhibit abnormal accumulation of the APC/C cofactor Cdh1 at the vicinity of centrioles. Furthermore, the ubiquitin ligase APC/CCdh1continuously degrades the centriolar protein STIL in these cells, thus inhibiting centriole assembly. Collectively our results demonstrate that NEK7 is involved in the timely regulation of G1 progression, S-phase entry, and procentriole formation.
Substrate binding by the yeast Hsp110 nucleotide exchange factor and molecular chaperone Sse1 is not obligate for its biological activities
Authors: Garcia Veronica M. , Nillegoda Nadinath B. , Bukau Bernd , Morano Kevin A.
Published: May 2017

The highly conserved heat shock protein 70 (Hsp70) is a ubiquitous molecular chaperone essential for maintaining cellular protein homeostasis. The related protein Hsp110 (Sse1/Sse2 in Saccharomyces cerevisiae) functions as a nucleotide exchange factor (NEF) to regulate the protein folding activity of Hsp70. Hsp110/Sse1 also can prevent protein aggregation in vitro via its substrate-binding domain (SBD), but the cellular roles of this “holdase” activity are poorly defined. We generated and characterized an Sse1 mutant that separates, for the first time, its nucleotide exchange and substrate-binding functions. Sse1sbd retains nucleotide-binding and nucleotide exchange activities while exhibiting severe deficiencies in chaperone holdase activity for unfolded polypeptides. In contrast, we observed no effect of the SBD mutation in reconstituted disaggregation or refolding reactions in vitro. In vivo, Sse1sbd successfully heterodimerized with the yeast cytosolic Hsp70s Ssa and Ssb and promoted normal growth, with the exception of sensitivity to prolonged heat but not other proteotoxic stress. Moreover, Sse1sbd was fully competent to support Hsp90-dependent signaling through heterologously expressed glucocorticoid receptor and degradation of a permanently misfolded protein, two previously defined roles for Sse1. We conclude that despite conservation among eukaryotic homologues, chaperone holdase activity is not an obligate function in the Hsp110 family.
Outcomes of stereotactic radiosurgery of brain metastases from neuroendocrine tumors
Authors: Prayongrat Anussara , Tao Randa , Allen Pamela K , Guha Nandita , Rao Ganesh , Zhao Zhongxiang , Li Jing , Brown Paul D , McGovern Susan L
Published: May 2017

Background

Stereotactic radiosurgery (SRS) is an established treatment for brain metastases, yet little is known about SRS for neuroendocrine tumors given their unique natural history.

Objective

To determine outcomes and toxicity from SRS in patients with brain metastases arising from neuroendocrine tumors.

Methods

Thirty-three patients with brain metastases from neuroendocrine tumors who underwent SRS were retrospectively reviewed. Median age was 61 years and median Karnofsky performance status was 80. Primary sites were lung (87.9%), cervix (6.1%), esophagus (3%), and prostate (3%). Ten patients (30.3%) received upfront SRS, 7 of whom had neuroendocrine tumors other than small cell lung carcinoma. Kaplan-Meier survival and Cox regression analyses were performed to determine prognostic factors for survival.

Results

With median follow-up after SRS of 5.3 months, local and distant brain recurrence developed in 5 patients (16.7%) and 20 patients (66.7%), respectively. Median overall survival (OS) after SRS was 6.9 months. Patients with progressive disease per Response Assessment in Neuro-Oncology-Brain Metastases (RANO-BM) criteria at 4 to 6 weeks after SRS had shorter median time to developing recurrence at a distant site in the brain and shorter OS than patients without progressive disease: 1.4 months and 3.3 months vs 11.4 months and 12 months, respectively (both P < .001). Toxicity was more likely in lesions of small cell histology than in lesions of other neuroendocrine tumor histology, 15.7% vs 3.3% (P = .021). No cases of grade 3 to 5 necrosis occurred.

Conclusions

SRS is an effective treatment option for patients with brain metastases from neuroendocrine tumors with excellent local control despite slightly higher toxicity rates than expected. Progressive disease at 4 to 6 weeks after SRS portends a poor prognosis.
Fat Grafting after Invasive Breast Cancer: A Matched Case-Control Study
Authors: Petit Jean Yves , Maisonneuve Patrick , Rotmensz Nicole , Bertolini Francesco , Rietjens Mario
Published: May 2017

Background:

Fat grafting has been widely indicated for postmastectomy and postlumpectomy breast reconstruction. The literature emphasizes the clinical efficacy of fat grafting, but experimental studies raise important questions about the recurrence risk because of the stimulation of remaining cancer cells by progenitor or adult adipocytes. Because breast conservative treatment provides a higher risk of residual cancer cells in the breast tissue compared with mastectomy, the authors set up a matched case-control study of fat grafting versus no fat grafting after breast conservative treatment.

Methods:

The authors collected data from 322 consecutive patients operated on for a primary invasive breast cancer who subsequently underwent fat grafting for breast reshaping from 2006 to 2013. All patients were free of recurrence before fat grafting. For each patient, the authors selected one patient with similar characteristics who did not undergo fat grafting.

Results:

After a mean follow-up of 4.6 years (range, 0.1 to 10.2 years) after fat grafting, or a corresponding time for controls, the authors observed no difference in the incidence of local events (fat grafting, n = 14; controls, n = 16; p = 0.49), axillary nodes metastasis (fat grafting, n = 3; controls, n = 6; p = 0.23), distant metastases (fat grafting, n = 14; controls, n = 15; p = 0.67), or contralateral breast cancer (fat grafting, n = 4; controls, n = 4; p = 0.51).

Conclusion:

Fat grafting seems to be a safe procedure after breast conservative treatment for breast cancer patients.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, III.
The Effect of Resident Involvement on Postoperative Short-Term Surgical Outcomes in Immediate Breast Reconstruction: A National Surgical Quality Improvement Program Study of 24,005 Patients
Authors: Sebai Mohamad E. , Bello Ricardo J. , Lifchez Scott D. , Cooney Damon S. , Rosson Gedge D. , Cooney Carisa M.
Published: May 2017

Background:

The association between resident involvement and surgical morbidity in immediate breast reconstruction is not fully elucidated, and prior studies have had conflicting results. The authors studied whether resident involvement in immediate breast reconstruction is associated with the most important short-term outcomes: increased 30-day surgical morbidity, readmission and reoperation rates, operative time, and length of stay.

Methods:

Patients undergoing immediate breast reconstruction were identified in the 2005 to 2012 American College of Surgeons National Surgical Quality Improvement Program Participant Use Data Files. The authors used simple and multivariable regression to assess surgical complications and secondary outcomes, stratifying by training level and reconstruction type.

Results:

A total of 24,191 patients underwent immediate breast reconstruction; 17,840 had resident involvement. Thirty-day surgical morbidity was observed in 5.25 percent (95 percent CI, 4.92 to 5.58 percent) of cases with resident involvement and 5.12 percent (95 percent CI, 4.59 to 5.58 percent) of cases without, with no evidence of association between resident involvement and 30-day morbidity (adjusted OR, 0.97; 95 percent CI, 0.85 to 1.11; p = 0.652). Resident involvement was not associated with an increase in complications in implant-based or mixed types of reconstruction, and was associated with lower odds of complications in autologous reconstructions (OR, 0.70; 95 percent CI, 0.53 to 0.91; p = 0.008). It was associated with longer operative times (an average of 24 additional minutes for implant-based and 54 additional minutes for autologous reconstructions; p < 0.001); this was balanced by a shorter length-of-stay for patients undergoing implant-based reconstruction (adjusted OR, 0.88; 95 percent CI, 0.79 to 0.96; p = 0.010).

Conclusion:

In immediate breast reconstruction patients, resident involvement was not associated with increased postoperative surgical morbidity or complications, although operative time was significantly increased with resident involvement across all levels of training.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, III.
Predicting Thrombosis Formation in 1-mm-Diameter Arterial Anastomoses with Transit-Time Ultrasound Technology
Authors: Shaughness Gabrielle , Blackburn Collin , Ballestín Alberto , Akelina Yelena , Ascherman Jeffrey A.
Published: May 2017

Background:

Thrombosis is a common source of failure in anastomoses, flaps, and vascular grafts. Ensuring vessel patency is critical to the success of microvascular procedures. Any tool that can accurately predict the patency of an anastomosis intraoperatively would enable the surgeon to detect and correct flow restrictions while the patient is still in the operating room.

Methods:

The authors used transit-time ultrasound technology in this pilot study to investigate whether a minimal cutoff value for quantitative postoperative blood flow (in milliliters per minute) could be established that would reliably predict sustained vessel patency at 24 hours postoperatively. Surgical end-to-end anastomoses were performed on 56 Sprague-Dawley rat femoral arteries with diameters ranging from 0.6 to 1.2 mm. Postoperative blood volume flow measurements were taken at 20-minute intervals up to 1 hour, and then again at 24 hours, to assess patency.

Results:

Forty-seven anastomoses (83.9 percent ) were patent 24 hours after surgery. Nine anastomoses (16.1 percent ) thrombosed within 24 hours. Based on a receiver operating characteristic curve analysis, the optimal cutoff value for immediate postoperative flow for predicting thrombosis within 24 hours of microvascular anastomosis is 0.21 ml/minute.

Conclusions:

At 20 minutes postoperatively, blood flows greater than 0.30 ml/minute are highly suggestive of patency, and flows less than 0.21 ml/minute are highly suggestive of failure. The authors therefore recommend a minimal cutoff flow value of 0.30 ml/minute for vessels ranging from 0.6 to 1.2 mm in diameter to predict long-term postoperative vascular patency.
Angiosome-Based Allografts: Vascularized Composite Allotransplantation for Tailored Subunit Reconstruction with Volkmann Ischemic Contracture as a Case in Point
Authors: Taylor G. Ian , Sparks David S. , Gascoigne Adam C. , Corlett Russell J. , Ashton Mark W.
Published: May 2017

Background:

As we enter an age with new approaches to tissue reconstruction, the emphasis on the adage “like for like” has become even more relevant. This study illustrates the potential for several tailored vascularized composite allotransplantation reconstructive techniques and, in particular, for the management of Volkmann contracture.

Methods:

Twenty fresh cadaver dissections and 30 archival lead oxide radiographic studies were examined to (1) identify potential upper limb vascularized composite allotransplantation donor sites (i.e., elbow, forearm, and flexor tendon complex) and (2) demonstrate a “mock transplant” of the vascularized volar forearm allograft for a severe Volkmann ischemia defect. They were designed without skin to reduce antigenicity.

Results:

The elbow joint was supplied within the brachial angiosome and the flexor tendon complex of the flexor digitorum superficialis and flexor digitorum profundus by the superficial palmar arch of the ulnar angiosome. The forearm allograft of flexor muscles, median, ulnar, and anterior interosseous nerves, when harvested on the brachial vessels, was supplied within the radial, ulnar, and anterior interosseous angiosomes but could be based on the ulnar artery alone because of intramuscular connections with the other territories. A mock transplant was performed with a distal-to-proximal dissection of the allograft, facilitating the best and fastest technique.

Conclusions:

This application of the angiosome concept highlights the anatomical feasibility of the volar forearm vascularized composite allotransplantation donor site focusing on a complex subunit problem in the upper limb—severe Volkmann ischemic contracture. It demonstrates the potential use and immunologic advantage of subdivided and modified nonskin variations of vascularized composite allotransplantation in reconstructive transplantation surgery.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, V.
The Effects of Motorcycle Helmet Legislation on Craniomaxillofacial Injuries
Authors: Adams Nicholas S. , Newbury Patrick A. , Eichhorn Mitchell G. , Davis Alan T. , Mann Robert J. , Polley John W. , Girotto John A.
Published: May 2017

Background:

Motorcycle helmet legislation has been a contentious topic for over a half-century. Benefits of helmet use in motorcycle trauma patients are well documented. In 2012, Michigan repealed its universal motorcycle helmet law in favor of a partial helmet law. The authors describe the early clinical effects on facial injuries throughout Michigan.

Methods:

Retrospective data from the Michigan Trauma Quality Improvement Program trauma database were evaluated. Included were 4643 motorcycle trauma patients presenting to 29 Level I and II trauma centers throughout Michigan 3 years before and after the law repeal (2009 to 2014). Demographics, external cause of injury codes, International Classification of Diseases, Ninth Revision diagnosis codes, and injury details were gathered.

Results:

The proportion of unhelmeted trauma patients increased from 20 percent to 44 percent. Compared with helmeted trauma patients, unhelmeted patients were nearly twice as likely to sustain craniomaxillofacial injuries (relative risk, 1.90), including fractures (relative risk, 2.02) and soft-tissue injuries (relative risk, 1.94). Unhelmeted patients had a lower Glasgow Coma Scale score and higher Injury Severity Scores. Patients presenting after helmet law repeal were more likely to sustain craniomaxillofacial injuries (relative risk, 1.46), including fractures (relative risk, 1.28) and soft-tissue injuries (relative risk, 1.56). No significant differences were observed for age, sex, Injury Severity Score, or Glasgow Coma Scale score (p > 0.05).

Conclusions:

This study highlights the significant negative impact of relaxed motorcycle helmet laws leading to an increase in craniomaxillofacial injuries. The authors urge state and national legislators to reestablish universal motorcycle helmet laws.
The Management of Trigonoscaphocephaly as a Result of Combined Metopic and Sagittal Synostosis
Authors: Dobbs Thomas D. , Salahuddin Omer , Jayamohan Jayaratnam , Richards Peter , Magdum Shailendra , Wall Steven A. , Johnson David
Published: May 2017

Background:

The combination of sagittal and metopic synostosis is rare, resulting in a scaphocephalic shape, but with an absence of frontal bossing and therefore varying degrees of trigonocephaly and occipital prominence. Treatment is primarily surgical, with a combination of procedures to address both the scaphocephaly and trigonocephaly required involving multiple operations. The authors discuss their experience of treating combined trigonoscaphocephaly in a single-stage procedure and propose a management strategy based on the severity of the presenting deformity.

Methods:

The Oxford Craniofacial Unit database was searched from inception in October of 2004 to August of 2013 to identify all patients with combined sagittal and metopic synostosis. Case notes were then manually searched to identify those patients who had true trigonoscaphocephaly.

Results:

Of 2856 patients in the authors’ database, a total of nine were identified as having had true trigonoscaphocephaly. Seven of these patients underwent a combined single-stage procedure with an average cephalic index of 68.7 percent preoperatively and 80.3 percent postoperatively.

Conclusions:

Management of trigonoscaphocephaly has been traditionally performed by multiple, staged surgical procedures. The authors propose that it can instead be managed in a single surgical procedure, with the choice of procedure determined by the severity of the deformity. If the deformity is mild to moderate with no occipital bullet, a combined fronto-orbital advancement remodeling and subtotal calvarial remodeling can be performed; however, if there is an occipital bullet, the authors propose the combination of fronto-orbital advancement remodeling and total calvarial remodeling performed in one operation with the patient turned from prone to supine intraoperatively.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, IV.
The Anatomy of the Facial Vein: Implications for Plastic, Reconstructive, and Aesthetic Procedures
Authors: Cotofana Sebastian , Steinke Hanno , Schlattau Alexander , Schlager Markus , Sykes Jonathan M. , Roth Malcolm Z. , Gaggl Alexander , Giunta Riccardo E. , Gotkin Robert H. , Schenck Thilo L.
Published: May 2017

Background:

Anatomical knowledge of the facial vasculature is crucial for successful plastic, reconstructive, and minimally invasive procedures of the face. Whereas the majority of previous investigations focused on facial arteries, the precise course, variability, and relationship with adjacent structures of the facial vein have been widely neglected.

Methods:

Seventy-two fresh frozen human cephalic cadavers (32 male and 40 female cadavers; mean age, 75.2 ± 10.9 years; mean body mass index, 24.2 ± 6.6 kg/m2; 99 percent Caucasian ethnicity) were investigated by means of layer-by-layer anatomical dissection. In addition, 10 cephalic specimens were investigated using contrast agent–enhanced computed tomographic imaging.

Results:

The facial vein displayed a constant course in relation to the adjacent anatomical structures. The vein was identified posterior to the facial artery, anterior to the parotid duct, and deep to the zygomaticus major muscle. The angular vein formed the lateral boundary of the deep medial cheek fat and the premaxillary space, and the medial boundary of the deep lateral cheek fat and the sub–orbicularis oculi fat. The mean distance of the inferior and superior labial veins, of the deep facial vein, and of the angular vein from the inferior orbital margin was 51.6 ± 3.1, 42.6 ± 2.3, 27.4 ± 3.0, and 4.2 ± 0.7 mm, respectively.

Conclusions:

This work provides detailed information on the course of the facial vein in relation to neighboring structures. The presented clinically relevant anatomical observations and descriptions of landmarks will serve as helpful information for plastic, reconstructive, and aesthetic surgeons.
In-Depth Review of Symptoms, Triggers, and Treatment of Occipital Migraine Headaches (Site IV)
Authors: Ascha Mona , Kurlander David E. , Sattar Abdus , Gatherwright James , Guyuron Bahman
Published: May 2017

Background:

This study reports the surgical technique and efficacy of deactivation of occipital-triggered migraine headaches. In addition, it reports the effect of surgical deactivation of occipital-triggered migraine headaches on migraine triggers and associated symptoms other than pain.

Methods:

One hundred ninety-five patients undergoing surgery for occipital-triggered migraine headaches performed by a single surgeon, and followed for at least 1 year, were analyzed. Median regression adjusted for age, sex, and follow-up time was used to determine postoperative reduction in occipital-specific Migraine Headache Index, which is the product of migraine duration, frequency, and severity. Reduction in migraine-days was also measured. The association between symptom or trigger resolution and occipital-specific Migraine Headache Index reduction was studied by logistic regression. Details of surgical treatment are discussed and complication rates reported.

Results:

Eighty-two percent of patients (n = 160) reported successful surgery at least 12 months postoperatively (mean follow-up, 3.67 years). Eighty-six percent (n = 168) had successful surgery as measured by migraine-days. Fifty-two percent reported complete occipital-triggered migraine headaches elimination. Symptoms resolving with successful surgery beyond headache include being bothered by light and noise, feeling lightheaded, difficulty concentrating, vomiting, blurred/double vision, diarrhea, visual aura, numbness and tingling, speech difficulty, and limb weakness (p < 0.05). Triggers resolving with successful surgery include missed meals; bright sunshine; loud noise; fatigue; certain smells; stress; certain foods; coughing, straining, and bending over; letdown after stress; and weather change (p < 0.05).

Conclusions:

Surgical deactivation of occipital-triggered migraine headaches provides long-lasting migraine relief. Successful site IV surgery is associated with changes in specific symptoms and triggers. This can assist in trigger avoidance and aid occipital-triggered migraine headache trigger-site identification.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, IV.
Beyond SNP Heritability: Polygenicity and Discoverability of Phenotypes Estimated with a Univariate Gaussian Mixture Model
Authors: Holland Dominic , Frei Oleksandr , Desikan Rahul , Fan Chun-Chieh , Shadrin Alexey A. , Smeland Olav B. , Sundar V. S. , Thompson Paul , Andreassen Ole A. , Dale Anders M.
Published: May 2017

Estimating the polygenicity (proportion of causally associated single nucleotide polymorphisms (SNPs)) and discoverability (effect size variance) of causal SNPs for human traits is currently of considerable interest. SNP-heritability is proportional to the product of these quantities. We present a basic model, using detailed linkage disequilibrium structure from an extensive reference panel, to estimate these quantities from genome-wide association studies (GWAS) summary statistics. We apply the model to diverse phenotypes and validate the implementation with simulations. We find model polygenicities ranging from ≃ 2 × 10−5to ≃ 4 × 10−3, with discoverabilities similarly ranging over two orders of magnitude. A power analysis allows us to estimate the proportions of phenotypic variance explained additively by causal SNPs reaching genome-wide significance at current sample sizes, and map out sample sizes required to explain larger portions of additive SNP heritability. The model also allows for estimating residual inflation (or deflation from over-correcting of z-scores), and assessing compatibility of replication and discovery GWAS summary statistics.

Author Summary

There are ~10 million common variants in the genome of humans with European ancestry. For any particular phenotype a number of these variants will have some causal effect. It is of great interest to be able to quantify the number of these causal variants and the strength of their effect on the phenotype.

Genome wide association studies (GWAS) produce very noisy summary statistics for the association between subsets of common variants and phenotypes. For any phenotype, these statistics collectively are difficult to interpret, but buried within them is the true landscape of causal effects. In this work, we posit a probability distribution for the causal effects, and assess its validity using simulations. Using a detailed reference panel of ~11 million common variants – among which only a small fraction are likely to be causal, but allowing for non-causal variants to show an association with the phenotype due to correlation with causal variants – we implement an exact procedure for estimating the number of causal variants and their mean strength of association with the phenotype. We find that, across different phenotypes, both these quantities – whose product allows for lower bound estimates of heritability – vary by orders of magnitude.
Overexpression of hypoxia-inducible factor 1 alpha improves immunomodulation by dental mesenchymal stem cells
Authors: Martínez VG. , Ontoria-Oviedo I. , Ricardo CP. , Harding SE. , Sacedón R. , Varas A. , Zapata A. , Sepúlveda P. , Vicente A.
Published: May 2017

Background

Human dental mesenchymal stem cells (MSCs) are considered as highly accessible and attractive MSCs for use in regenerative medicine, yet some of their features are not as well characterized as in other MSCs. Hypoxia-preconditioning and hypoxia inducible factor 1 alpha (HIF-1 alpha) overexpression significantly improve MSC therapeutics, but the mechanisms involved are not fully understood. In the present study, we characterize immunomodulatory properties of dental MSCs and determine changes in their ability to modulate adaptive and innate immune populations after HIF-1 alpha overexpression.

Methods

Human dental MSCs were stably transduced with GFP (MSCs) or GFP-HIF-1 alpha lentivirus vectors (HIF-MSCs). Hypoxic-like metabolic profile was confirmed by mitochondrial and glycolysis stress test. Capacity of HIF-MSCs to modulate T cell activation, dendritic cell differentiation, monocyte migration and polarizations towards macrophages and NK cell lytic activity was assessed by a number of functional assays in co-cultures. Expression of relevant factors were determined by PCR analysis and ELISA.

Results

While HIF-1 alpha overexpression did not modify inhibition of T cell activation by MSCs, HIF-MSCs impaired dendritic cell differentiation more efficiently. HIF-MSCs induced also higher attraction of monocytes, which differentiate into suppressor macrophages, and exhibited enhanced resistance to NK cell-mediated lysis, which support the improved therapeutic capacity of HIF-MSCs. HIF-MSCs also displayed a pro-angiogenic profile characterized by increased expression ofCXCL12/SDF1andCCL5/RANTESand complete loss ofCXCL10/IP10transcription.

Conclusions

Immunomodulation and expression of trophic factors by dental MSCs make them perfect candidates for cell therapy. Overexpression of HIF-1 alpha enhances these features and increases their resistance to allogenic NK cell lysis and, hence, their potentialin vivolifespan. Our results further support the use of HIF-1 alpha-expressing dental MSCs for cell therapy in tissue injury and immune disorders.
Disruption of ankyrin B and caveolin-1 interaction sites alters Na+,K+-ATPase lateral diffusion in HEK293 cell plasma membranes
Authors: Junghans Cornelia , Vukojević Vladana , Tavraz Neslihan N. , Maksimov Eugene G. , Zuschratter Werner , Schmitt Franz-Josef , Friedrich Thomas
Published: May 2017

The Na+,K+-ATPase is a plasma membrane ion transporter of high physiological importance for ion homeostasis and cellular excitability in electrically active tissues. Mutations in the genes coding for Na+,K+-ATPase α-subunit isoforms lead to severe human pathologies including Familial Hemiplegic Migraine type 2 (FHM2), Alternating Hemiplegia of Childhood (AHC), Rapid Dystonia Parkinsonism (RDP) or epilepsy. Many of the reported mutations lead to change- or loss-of-function effects, whereas others do not alter the functional properties, but lead to e.g. reduced protein stability, reduced protein expression or defective plasma membrane targeting. Na+,K+-ATPase frequently assembles with other membrane transporters or cellular matrix proteins in specialized plasma membrane microdomains, but the effects of these interactions on targeting or protein mobility are elusive so far. Mutational disruption of established interaction motifs of the Na+,K+-ATPase with ankyrin B and caveolin-1 are expected to result in changes in plasma membrane targeting, changes of the localization pattern, and of the diffusion behavior of the enzyme. We studied the consequences of mutations in these binding sites by monitoring diffusion of eGFP-labeled Na+,K+-ATPase constructs in the plasma membrane of living HEK293T cells by fluorescence correlation spectroscopy (FCS) as well as fluorescence recovery after photobleaching (FRAP) or photoswitching (FRAS) and observed significant differences compared to the wild-type enzyme, with synergistic effects for combinations of interaction site mutations. These measurements expand the possibilities to study the consequences of Na+,K+-ATPase mutations and provide information about the interaction of Na+,K+-ATPase α2-isoform with cellular matrix proteins, the cytoskeleton or other membrane protein complexes.
A Feedback Motif that Breaks the Fundamental Limit on Noise Suppression to Stabilize Fate
Authors: Wen Winnie Y. , Ingerman Elena , Hansen Maike M. K. , Razooky Brandon S. , Dar Roy D. , Chin Charles , Simpson Michael , Weinberger Leor S.
Published: May 2017

Diverse biological systems utilize gene-expression fluctuations (‘noise’) to drive lineage-commitment decisions1-5. However, once a commitment is made, noise becomes detrimental to reliable function6,7and the mechanisms enabling post-commitment noise suppression are unclear. We used time-lapse imaging and mathematical modeling, and found that, after a noise-driven event, human immunodeficiency virus (HIV) strongly attenuated expression noise through a non-transcriptional negative-feedback circuit. Feedback is established by serial generation of RNAs from post-transcriptional splicing, creating a precursor-product relationship where proteins generated from spliced mRNAs auto-deplete their own precursor un-spliced mRNAs. Strikingly, precursor auto-depletion overcomes the theoretical limits on conventional noise suppression—minimizing noise far better than transcriptional auto-repression—and dramatically stabilizes commitment to the active-replication state. This auto-depletion feedback motif may efficiently suppress noise in other systems ranging from detained introns to non-sense mediated decay.
Potential mechanisms linking SIRT activity and hypoxic 2-hydroxyglutarate generation: no role for direct enzyme (de)acetylation
Authors: Nadtochiy Sergiy M. , Wang Yves T. , Zhang Jimmy , Nehrke Keith , Schafer Xenia , Welle Kevin , Ghaemmaghami Sina , Munger Josh , Brookes Paul S.
Published: May 2017

2-hydroxyglutarate (2-HG) is a hypoxic metabolite with potentially important epigenetic signaling roles. The mechanisms underlying 2-HG generation are poorly understood, but evidence suggests a potential regulatory role for the sirtuin family of lysine deacetylases. Thus, we hypothesized that the acetylation status of the major 2-HG-generating enzymes (isocitrate dehydrogenase (IDH), malate dehydrogenase (MDH) and lactate dehydrogenase (LDH)) may govern their 2-HG generating activity.In-vitroacetylation of these enzymes, with confirmation by western blotting, mass spectrometry, and reversibility by incubation with recombinant sirtuins, yielded no effect on 2-HG generating activity. In addition, while elevated 2-HG in hypoxia is associated with the activation of lysine deacetylases, we found that mice lacking mitochondrial SIRT3 exhibited hyperacetylation and elevated 2-HG. These data suggest there is no direct link between enzyme acetylation and 2-HG production. Furthermore, our observed effects ofin-vitroacetylation on the canonical activities of IDH, MDH and LDH appeared to contrast sharply with previous findings wherein acetyl-mimetic lysine mutations resulted in inhibition of these enzymes. Overall these data suggest that a causal relationship should not be assumed, between acetylation of metabolic enzymes and their activities, canonical or otherwise.
Efficiency of genomic prediction of non-assessed single crosses
Authors: Viana José Marcelo Soriano , Pereira Helcio Duarte , Mundim Gabriel Borges , Piepho Hans-Peter , Silva Fabyano Fonseca e
Published: May 2017

An important application of genomic selection in plant breeding is the prediction of untested single crosses (SCs). Most investigations on the prediction efficiency were based on tested SCs, using cross-validation. The main objective was to assess the prediction efficiency by correlating the predicted and true genotypic values of untested SCs (accuracy) and measuring the efficacy of identification of the best 300 untested SCs (coincidence), using simulated data. We assumed 10,000 SNPs, 400 QTLs, two groups of 70 selected DH lines, and 4,900 SCs. The heritabilities for the assessed SCs were 30, 60 and 100%. The scenarios included three sampling processes of DH lines, two sampling processes of SCs for testing, two SNP densities, DH lines from distinct and same populations, DH lines from populations with lower LD, two genetic models, three statistical models, and three statistical approaches. We derived a model for genomic prediction based on SNP average effects of substitution and dominance deviations. The prediction accuracy is not affected by the linkage phase. The prediction of untested SCs is very efficient. The accuracies and coincidences ranged from approximately 0.8 and 0.5, respectively, under low heritability, to 0.9 and 0.7, assuming high heritability. Additionally, we highlighted the relevance of the overall LD and evidenced that efficient prediction of untested SCs can be achieved for crops that show no heterotic pattern, for reduced training set size (10%), for SNP density of 1 cM, and for distinct sampling processes of DH lines, based on random choice of the SCs for testing.
Characterization of Beta Tubulin Isotypes During Foam Cell Formation
Authors: Torres A. , Contreras-Shannon V.
Published: May 2017

Foam cells contribute to the development of a cardiovascular condition called atherosclerosis. They arise when monocytes become engorged and lipid-laden after exposure to native low-density lipoproteins (Falk, 2006). It is assumed that the cytoskeleton is responsible for the morphological changes observed during foam cell formation. Beta tubulin and alpha tubulin are proteins that dimerize and polymerize to form microtubules, which are an important component of the cytoskeleton (Joshi, 1998). Little is known regarding the changes in cytoskeletal composition, particularly that of beta tubulins, throughout foam cell induction. The purpose of this study was to elucidate the expression patterns of beta tubulin isotypes 1–4 in human THP-1 monocytes throughout foam cell formation and to determine what relationship exists between beta tubulin expression and foam cell lipid aggregation. Levels of beta tubulin 1–4 were measured by western blot and immunofluorescence throughout the stages of foam cell differentiation, and beta tubulin isotypes were manipulated by siRNA to determine the effects of diminished beta tubulin expression on foam cell formation. Regardless of isotype, beta tubulin was always present in the highest amounts in monocytes. Levels of beta tubulin-1 and -4 were significantly decreased in macrophage and foam cells relative to monocytes (p < 0.0079, p < 0.0208, respectively). Beta 3 levels also exhibited a decrease. Beta 2 levels remained low regardless of differentiation stage. The distribution of beta tubulin 1 was shown to be more spindle-like (stretching across cells), compared to beta tubulins 2, 3, and 4, which exhibited a more “clumped,” less interconnected arrangement. When expression of beta tubulin isotypes 1, 3, and 4 were reduced in monocytes, resulting foam cells appeared to have more lipid aggregates and were significantly larger (p<0.0001) when compared to the size of foam cells without siRNA following treatment with PMA + LDL. In conclusion, the distribution of beta tubulins 1, 3, and 4 changes throughout the stages of foam cell induction, and manipulation of beta tubulins altered foam cell formation. Unexpectedly, the silencing or decreasing of beta tubulin enhanced lipid aggregation. Information concerning how beta tubulin expression can effect foam cell formation may offer insight into how to reduce plaque formation in patients with atherosclerosis.
Translational repression of theDrosophila nanosmRNA involves the RNA helicase Belle and RNA coating by Me31B and Trailer hitch
Authors: Götze Michael , Dufourt Jérémy , Ihling Christian , Rammelt Christiane , Pierson Stéphanie , Sambrani Nagraj , Temme Claudia , Sinz Andrea , Simonelig Martine , Wahle Elmar
Published: May 2017

Translational repression of maternal mRNAs is an essential regulatory mechanism during early embryonic development. Repression of theDrosophila nanosmRNA, required for the formation of the anterior-posterior body axis, depends on the protein Smaug binding to two Smaug recognition elements (SREs) in thenanos3’ UTR. In a comprehensive mass-spectrometric analysis of the SRE-dependent repressor complex, we identified Smaug, Cup, Me31B, Trailer hitch, eIF4E and PABPC, in agreement with earlier data. As a novel component, the RNA-dependent ATPase Belle (DDX3) was found, and its involvement in deadenylation and repression ofnanoswas confirmedin vivo. Smaug, Cup and Belle bound stoichiometrically to the SREs, independently of RNA length. Binding of Me31B and Tral was also SRE-dependent, but their amounts were proportional to the length of the RNA and equimolar to each other. We suggest that ‘coating’ of the RNA by a Me31B•Tral complex may be at the core of repression.
Genetic Identification of a Common Collagen Disease in Puerto Ricans via Identity-by-Descent Mapping in a Health System
Authors: Belbin G.M. , Odgis J. , Sorokin E.P. , Yee M-C. , Kohli S. , Glicksberg B.S. , Gignoux C.R. , Wojcik G.L. , Van Vleck T. , Jeff J.M. , Linderman M. , Schurmann C. , Ruderfer D. , Cai X. , Merkelson A. , Justice A.E. , Young K.L. , Graff M , North K.E. , Peter U. , James R. , Hindorff L. , Kornreich R. , Edelmann L. , Gottesman O. , Stahl E.E.A. , Cho J.H. , Loos R.J.F. , Bottinger E.P. , Nadkarni G.N. , Abul-Husn N. S. , Kenny E.E.
Published: May 2017

Achieving confidence in the causality of a disease locus is a complex task that often requires supporting data from both statistical genetics and clinical genomics. Here we describe a combined approach to identify and characterize a genetic disorder that leverages distantly related patients in a health system and population-scale mapping. We utilize genomic data to uncover components of distant pedigrees, in the absence of recorded pedigree information, in the multi-ethnic BioMe biobank in New York City. By linking to medical records, we discover a locus associated with genetic relatedness that also underlies extreme short stature. We link the gene, COL27A1, with a little-known genetic disease, previously thought to be rare and recessive. We demonstrate that disease manifests in both heterozygotes and homozygotes, indicating a common collagen disorder impacting up to 2% of individuals of Puerto Rican ancestry, leading to a better understanding of the continuum of complex and Mendelian disease.
Inter-individual Recovery of the Microbiota and Metabolome Over Time Following Fecal Microbiota Transplantation in Patients with RecurrentClostridium difficileInfection
Authors: Seekatz Anna M. , Theriot Casey M. , Rao Krishna , Chang Yu-Ming , Freeman Alison E. , Kao John Y. , Young Vincent B.
Published: May 2017

A significant proportion of individuals develop recurrentClostridium difficileinfection (CDI) following initial disease. Fecal microbiota transplantation (FMT), a highly effective treatment method for recurrent CDI, has been demonstrated to induce microbiota recovery, a critical component of disease recovery. However, identification of the specific microbes and their functions that directly impact recovery from CDI remains difficult. We assessed for associations among microbial community members and metabolites in patients with recurrent CDI following treatment with FMT over time to identify groups of bacteria with potential restorative functions. Using 16S rRNA gene-based sequencing, we observed marked similarity of the microbiota between recipients following FMT (n = 6, sampling up to 6 months post-FMT) and their respective donors. Increased levels of the secondary bile acid deoxycholic acid and the short chain fatty acids (SCFAs) butyrate, acetate, and propionate were observed post-FMT. To take into account longitudinal sampling and intra-individual differences, we applied a generalized estimating equation approach to model metabolite concentrations with the presence of specific members of the microbiota. Microbial metabolites that were increased following FMT associated with members classified within theLachnospiraceae, Ruminococcaceae, and unclassifiedClostridialesfamilies. In contrast, members of these taxa were inversely associated with primary bile acids. The longitudinal aspect of this study allowed us to characterize individualized patterns of recovery, revealing variability between and within patients following FMT.

IMPORTANCE

Clostridium difficileinfection (CDI) is an urgent and serious healthcare-associated problem. In recent years, fecal microbiota transplantation (FMT) has been successfully used to treat recurrent CDI, a frequent outcome of disease. While it is apparent that FMT promotes recovery of the microbiota, it is unclear how microbes and their functions promote recovery from disease. This study aimed to identify associations among microbes and metabolites following FMT and to identify critical microbial functions following FMT treatment for recurrent CDI. Overall, recovery of the metabolome was highly dynamic and individualized in all patients, who were all successfully treated. Our results suggest that microbial changes following FMT may be highly specific to the donor-recipient relationship. Further understanding of the host-microbe environments necessary to enable successful transplantation of microbes during FMT could aid development of specific microbial therapeutics for recurrent CDI and other gastrointestinal diseases.
Distributed Rhythm Generators UnderlieCaenorhabditis elegansForward Locomotion
Authors: Fouad Anthony D. , Teng Shelly , Mark Julian R. , Liu Alice , Alvarez-Illera Pilar , Ji Hongfei , Du Angelica , Bhirgoo Priya D. , Cornblath Eli , Guan Asuka , Fang-Yen Christopher
Published: May 2017

Coordinated rhythmic movements are ubiquitous in animal behavior. In many organisms, chains of neural oscillators underlie the generation of these rhythms. InC. elegans, locomotor wave generation has been poorly understood; in particular, it is unclear where in the circuit rhythms are generated, and whether there exists more than one such generator. We used optogenetic and ablation experiments to probe the nature of rhythm generation in the locomotor circuit. We found that multiple sections of forward locomotor circuitry are capable of independently generating rhythms. By perturbing different components of the motor circuit, we localize the source of secondary rhythms to cholinergic motor neurons in the midbody. Using rhythmic optogenetic perturbation we demonstrate bidirectional entrainment of oscillations between different body regions. These results show that, as in many other vertebrates and invertebrates, theC. elegansmotor circuit contains multiple oscillators that coordinate activity to generate behavior.
CrystalWalk: crystal structures, step by step
Authors: Bardella Fernando , Montes Rodrigues Andre , Leal Neto Ricardo Mendes
Published: May 2017

CrystalWalk is a crystal editor and visualization software designed for teaching materials science and engineering. Based on WebGL/HTML5, it provides an accessible and interactive platform to students and teachers by introducing a simplified crystallographic approach that creates crystal structures by combining a lattice with a motif without the use of its internal symmetry. CrystalWalk is the first software to use solely translational symmetry, aiming to introduce engineering students to the basic concepts of lattice and motif. Although very restrictive from the crystallographic point of view, CrystalWalk makes it simple for students to experiment, reproduce and visualize, in an interactive manner, most of the crystal structures that are commonly introduced in materials science and engineering curricula.
Strategic challenges of outsourcing innovation in global market
Authors: Yeo ChangSeob , Saboori-Deilami Vafa
Published: May 2017

Purpose

The purpose of this study is to theoretically clarify under which circumstances MNCs should outsource the innovation function. In the globalization era, multinational companies (MNCs) face the challenge of making a strategic decision. They ought to adjudicate upon outsourcing the research and development, i.e. innovation function and bearing the risks of it, or keeping innovation function in house and paying the price of this decision. This decision becomes more crucial when the host country has dissimilar characteristic and high uncertainty compared to the home country.

Design/methodology/approach

This study is among the very first studies that evaluate the issue of outsourcing innovation for MNCs from a transaction cost economics (TCE) theoretical perspective. By setting forward propositions that serve as a guideline for conditions in which MNCs should outsource innovation, this paper contributes to innovation, new product development, global business and, last but not least, to the TCE literature. This study also provides managerial implications and avenues of future research for academicians.

Findings

This study shows that heterogeneity between the home and host country affects the autonomy of the innovation at the host country; this autonomy in turn leads to higher transaction cost, and finally, transaction cost is the main determinant of the decision on whether to outsource the innovation.

Originality/value

This study fills this gap by looking at the problem of outsourcing innovation from a TCE theoretical perspective and, based on an extensive literature review, puts forward a set of propositions that clarify under which circumstances MNCs should outsource the innovation function.