The Influence of Intermittent Hypoxia on Erythropoietin Levels in Older Adults

Few minutes of hypoxia exposure stabilizes hypoxia-inducible factors, resulting in erythropoietin (EPO) gene transcription and production. A brief intermittent hypoxia exposure increased EPO levels in young healthy adults, suggesting that a single session of intermittent hypoxia has the potential to increase oxygen-carrying capacity. PURPOSE: To determine the effect of a single session of intermittent hypoxia on serum EPO levels and hemoglobin mass among older adults. We hypothesized that a single session of intermittent hypoxia would raise serum EPO levels and lead to an increase in hemoglobin mass in older adults. METHODS: Seventeen participants (8 women, age: 54 ± 8 years, height: 177 ± 10 cm, weight: 76 ± 14 kg, BMI: 24 ± 4 kg/m2) were randomly assigned to an intermittent hypoxia group (IH, n=11) or an intermittent normoxia group (IN, n=6). Intermittent hypoxia consisted of eight 4-minute cycles at a targeted arterial oxygen saturation of 80% interspersed with normoxic cycles to resaturation. Air was made hypoxic by titrating nitrogen into the breathing circuit. Intermittent normoxia consisted of the same protocol, but nitrogen was not added to the breathing circuit. Pulmonary gas exchange, arterial oxygen saturation, and hemodynamics were continuously measured throughout both protocols. EPO levels were measured before and 4.5 hours after the beginning of each protocol. Hemoglobin mass was assessed via carbon monoxide rebreathing the day before and seven days following intermittent hypoxia or normoxia. RESULTS: Intermittent hypoxia lowered arterial oxygen saturation (­­98 ±­ 1 to 82 ± 3 %, p\u3c0.01), which resulted in a lower fraction of inspired oxygen (20.8 ±­ 0.1 to 10.9 ± 1.0 %, p\u3c0.01). There was no significant change in EPO levels in either condition (IH:10.4 ±­ 2.9 to 13.3 ± 4.2; IN: 5.6 ±­ 2.4 to 6.5 ± 2.9 mU/ml, main effect for time p=0.12). Similarly, there was no change in hemoglobin mass in response to both conditions (IH: 752 ±­ 189 to 754 ± 189; IN: 858 ± 177 to 879 ± 157 g, main effect for time p=0.87). Intermittent hypoxia did not affect mean arterial pressure (87 ± 15 to 88 ± 14 mmHg, p=0.18) or cardiac output (5.5 ± 1.5 to 5.7 ± 1.5 L/min, p=0.22), but increased heart rate (62 ± 9 to 68 ± 9 bpm, p\u3c0.01). CONCLUSION: A single session of eight 4-minute cycles of intermittent hypoxia did not increase serum EPO levels in older adults

Hypoxic Preconditioning Attenuates Ischemia-reperfusion Injury in Older Adults

Sudden restoration of blood flow to an ischemic vessel paradoxically damages endothelial cells. In young healthy adults, ischemic preconditioning, caused by repeated periods of brief ischemia induced by local cuff inflation prior to reperfusion, attenuates endothelial dysfunction following an ischemia-reperfusion injury. However, ischemic preconditioning does not consistently protect against ischemia-reperfusion injury in older adults. Intermittent systemic hypoxemia, induced via brief bouts of breathing low levels of oxygen, attenuates endothelial dysfunction following an ischemia-reperfusion injury in young adults. PURPOSE: To determine whether intermittent hypoxia protects against ischemia-reperfusion injury in older adults. METHODS: Twelve older adults (5 women, age: 57 ± 9 years, height: 173 ± 8 cm, body weight: 75.8 ± 13.4 kg) visited the laboratory on two separate occasions. Endothelium-dependent vasodilation was assessed by brachial artery flow-mediated dilation using a semiautomated diagnostic ultrasound system before and after 20 minutes of upper arm blood flow occlusion to induce an ischemia-reperfusion injury. Blood flow occlusion was preceded by either intermittent hypoxia, consisting of three 4-minute hypoxic cycles at a targeted arterial oxygen saturation of 80% interspersed with 4-minute room air cycles, or intermittent normoxia, consisting of three 4-minute normoxic cycles separated by 4-minute room air cycles. RESULTS: Intermittent hypoxia resulted in an arterial oxygen saturation of 80 ± 2%, which corresponded to oxygen levels of 11.4 ± 0.7%. When preceded by intermittent normoxia, blood flow occlusion reduced flow-mediated dilation by 4.1 ± 2.6% (6.5 ± 1.7 to 2.4 ± 1.7%). In contrast, flow-mediated dilation was reduced by 2.0 ± 1.5% when blood flow occlusion was preceded by intermittent hypoxia (5.6 ± 1.7 to 3.6 ± 2.3%, P = 0.03). When compared to intermittent normoxia, intermittent hypoxia resulted in a greater heart rate (60 ± 10 vs. 68 ± 10 bpm, P \u3c 0.01) but did not affect cardiac output (5.1 ± 1.4 vs. 5.8 ± 1.8 L/min, P = 0.11). CONCLUSION: Hypoxic preconditioning attenuated the reduction in flow-mediated dilation induced by a 20-minute blood flow occlusion in older adults. Thus, exposure to intermittent hypoxia represents a promising strategy to protect against ischemia-reperfusion injury in populations at risk for ischemic events

Preface

These proceedings contain the papers of the Third International Workshop on Recent Trends in News Informa-tion Retrieval (NewsIR\u201919) held in conjunction with the ACM SIGIR 2019 conference in Paris, France, on the25thof July 2019. Ten full papers and two short papers (one position paper and one demo paper) were selectedby the programme committee from a total of 21 submissions. Each submitted paper was reviewed by at leastthree members of an international programme committee. In addition to the selected papers, the workshopfeatures one keynote and one invited talk. The Keynote speech is given by Aron Pilhofer \u201cFrom Redlining toRobots: How newsrooms apply technology to the craft of journalism\u201d. The invited talk is given by FriedrichLindenberg \u201cMining Leaks and Open Data to Follow the Money\u201d. We would like to thank SIGIR for hostingus. Thanks also go to the keynote speakers, the program committee, the paper authors, and the participants,for without these people there would be no worksho

Defining the Dose of Altitude Training: How High to Live for Optimal Sea Level Performance Enhancement

Defining the dose of altitude training: how high to live for optimal sea level performance enhancement. J Appl Physiol 116: 595-603, 2014. First published October 24, 2013; doi:10.1152/japplphysiol.00634.2013.-Chronic living at altitudes of 2,500 m causes consistent hematological acclimatization in most, but not all, groups of athletes; however, responses of erythropoietin (EPO) and red cell mass to a given altitude show substantial individual variability. We hypothesized that athletes living at higher altitudes would experience greater improvements in sea level performance, secondary to greater hematological acclimatization, compared with athletes living at lower altitudes. After 4 wk of group sea level training and testing, 48 collegiate distance runners (32 men, 16 women) were randomly assigned to one of four living altitudes (1,780, 2,085, 2,454, or 2,800 m). All athletes trained together daily at a common altitude from 1,250-3,000 m following a modified live high-train low model. Subjects completed hematological, metabolic, and performance measures at sea level, before and after altitude training; EPO was assessed at various time points while at altitude. On return from altitude, 3,000-m time trial performance was significantly improved in groups living at the middle two altitudes (2,085 and 2,454 m), but not in groups living at 1,780 and 2,800 m. EPO was significantly higher in all groups at 24 and 48 h, but returned to sea level baseline after 72 h in the 1,780-m group. Erythrocyte volume was significantly higher within all groups after return from altitude and was not different between groups. These data suggest that, when completing a 4-wk altitude camp following the live high-train low model, there is a target altitude between 2,000 and 2,500 m that produces an optimal acclimatization response for sea level performance

A study of the Scrum Master’s role

Scrum is an increasingly common approach to software development adopted by organizations around the world. However, as organizations transition from traditional plan-driven development to agile development with Scrum, the question arises as to which Scrum role (Product Owner, Scrum Master, or Scrum Team Member) corresponds to a Project Manager, or conversely which Scrum role should the Project Managers adopt? In an attempt to answer this question, we adopted a mixed-method research approach comprising a systematic literature review and embedded case study of a commercial software development team. Our research has identified activities that comprise the Scrum Master role, and which additional roles are actually performed by Scrum Masters in practice. We found nine activities that are performed by Scrum Masters. In addition, we found that Scrum Masters also perform other roles, most importantly as Project Managers. This latter situation results in tension and conflict of interest that could have a negative impact on the performance of the team as a whole. These results point to the need to re-assess the role of Project Managers in organizations that adopt Scrum as a development approach. We hypothesize that it might be better for Project Managers to become Product Owners, as aspects of this latter role are more consistent with the traditional responsibilities of a Project Manager

BMC Medicine editorial board members on open access publishing.

In recognition of Open Access week (21st-27th October 2013), we asked some BMC Medicine Editorial Board Members to share their views and experiences on open access publishing. In this short video, they highlight the benefits of visibility and dissemination of their research, and discuss the future directions for this model of publishing

Evaluating the contribution of APOBEC3G haplotypes, on influencing HIV infection in a Zimbabwean paediatric population

Background. Apolipoprotein B mRNA-editing catalytic polypeptide like-3G (APOBEC3G) is an antiviral enzyme that reduces viral fitness by introducing uracil to thymidine hypermutations in viral genomes. Thus, polymorphisms in the APOBEC3G gene have been implicated in differential outcomes of HIV infection and disease progression. However, there is insufficient evidence on the role of APOBEC3G gene variants on HIV infection, especially in African populations. This study therefore describes polymorphisms in the APOBEC3G gene in a Zimbabwean paediatric population and evaluates their effects on susceptibility to HIV infection among children born to HIV-infected mothers. Methods. A total of 104 children aged between 7 and 9 years, comprising 68 perinatally exposed to HIV (32 born infected (EI) and 36 born uninfected (EU)) and 36 unexposed and uninfected (UEUI) controls were recruited. Allelic variants (n=5) in the APOBEC3G gene were characterised. Results. Frequencies for minor APOBEC3G alleles in the HIV-uninfected groups (EU and UEUI) were c.557G (40%), g.-90C (32%), g.-571C (12%), c.467-85C (42%), and c.582-162G (6%). APOBEC3G c.467-85C frequency was statistically significantly different when compared to the Masai of Kinyawa, Kenya population (42% v. 18%). None of the single nucleotide polymorphisms individually or as part of haplotypes were significantly associated with HIV infection when comparing the EI and EU groups. Conclusions. Our findings suggest that APOBEC3G polymorphisms alone may not have significant predictive power for inferring genetic susceptibility to vertical transmission of HIV in children perinatally exposed to HIV

HIV Gag mimics the Tsg101-recruiting activity of the human Hrs protein

The HIV-1 Gag protein recruits the cellular factor Tsg101 to facilitate the final stages of virus budding. A conserved P(S/T)AP tetrapeptide motif within Gag (the “late domain”) binds directly to the NH2-terminal ubiquitin E2 variant (UEV) domain of Tsg101. In the cell, Tsg101 is required for biogenesis of vesicles that bud into the lumen of late endosomal compartments called multivesicular bodies (MVBs). However, the mechanism by which Tsg101 is recruited from the cytoplasm onto the endosomal membrane has not been known. Now, we report that Tsg101 binds the COOH-terminal region of the endosomal protein hepatocyte growth factor–regulated tyrosine kinase substrate (Hrs; residues 222–777). This interaction is mediated, in part, by binding of the Tsg101 UEV domain to the Hrs 348PSAP351 motif. Importantly, Hrs222–777 can recruit Tsg101 and rescue the budding of virus-like Gag particles that are missing native late domains. These observations indicate that Hrs normally functions to recruit Tsg101 to the endosomal membrane. HIV-1 Gag apparently mimics this Hrs activity, and thereby usurps Tsg101 and other components of the MVB vesicle fission machinery to facilitate viral budding

Information flows at inter-team boundaries in agile information systems development

Agile software development methods are being used on larger projects thus the study of inter-team communication are becoming an important topic of interest for researchers. This research addresses inter-team communication by exploring the tools and three different boundaries, inter-team, team and customers, and geographically separated teams. In this research, we gathered data from semi-structured face-to-face interviews which were analyzed following the grounded theory approach. Our study reveals consensus from different teams on the importance of virtual Kanban boards. Also, some teams members tend to adapt to other teams’ preferred communication tool. We observed challenges around interdependent user stories among the different teams and highlighted the problems that rise at the different boundaries. Keywords: agile information system development • inter-team communication • agile team boundary • communication • agile methods • cooperating agile team

Understanding Work Practices of Autonomous Agile Teams: A Social-psychological Review

The purpose of this paper is to suggest additional aspects of social psychology that could help when making sense of autonomous agile teams. To make use of well-tested theories in social psychology and instead see how they replicated and differ in the autonomous agile team context would avoid reinventing the wheel. This was done, as an initial step, through looking at some very common agile practices and relate them to existing findings in social-psychological research. The two theories found that I argue could be more applied to the software engineering context are social identity theory and group socialization theory. The results show that literature provides social-psychological reasons for the popularity of some agile practices, but that scientific studies are needed to gather empirical evidence on these under-researched topics. Understanding deeper psychological theories could provide a better understanding of the psychological processes when building autonomous agile team, which could then lead to better predictability and intervention in relation to human factors