Historical Perspectives: Physiology in microgravity

2000 ◽  
Vol 89 (1) ◽  
pp. 379-384 ◽  
Author(s):  
John B. West

Studies of physiology in microgravity are remarkably recent, with almost all the data being obtained in the past 40 years. The first human spaceflight did not take place until 1961. Physiological measurements in connection with the early flights were crude, but, in the past 10 years, an enormous amount of new information has been obtained from experiments on Spacelab. The United States and Soviet/Russian programs have pursued different routes. The US has mainly concentrated on relatively short flights but with highly sophisticated equipment such as is available in Spacelab. In contrast, the Soviet/Russian program concentrated on first the Salyut and then the Mir space stations. These had the advantage of providing information about long-term exposure to microgravity, but the degree of sophistication of the measurements in space was less. It is hoped that the International Space Station will combine the best of both approaches. The most important physiological changes caused by microgravity include bone demineralization, skeletal muscle atrophy, vestibular problems causing space motion sickness, cardiovascular problems resulting in postflight orthostatic intolerance, and reductions in plasma volume and red cell mass. Pulmonary function is greatly altered but apparently not seriously impaired. Space exploration is a new frontier with long-term missions to the moon and Mars not far away. Understanding the physiological changes caused by long-duration microgravity remains a daunting challenge.

2015 ◽  
Vol 29 (4) ◽  
pp. 89-112 ◽  
Author(s):  
Ali Hortaçsu ◽  
Chad Syverson

The past 15–20 years have seen substantial and visible changes in the way US retail business is conducted. Explanations about what is happening in the retail sector have been dominated by two powerful and not fully consistent narratives: a prediction that retail sales will migrate online and physical retail will be virtually extinguished, and a prediction that future shoppers will almost all be heading to giant physical stores like warehouse clubs and supercenters. Although online retail will surely continue to be a force shaping the sector going forward and may yet emerge as the dominant mode of commerce in the retail sector in the United States, its time for supremacy has not yet arrived. We discuss evidence indicating that the warehouse clubs/supercenter format has had a greater effect on the shape of retail over the past 15–20 years We begin with an overview of the retail sector as a whole, which over the long term has been shrinking as a share of total US economic activity and in terms of relative employment share. The retail sector has experienced stronger-than average productivity growth, but this has not been accompanied by commensurate wage growth. After discussing the important e-commerce and warehouse clubs/supercenters segments, we look more broadly at changes across the structure of the retail sector, including scale, concentration, dynamism, and degree of urbanization. Finally, we consider the likely future course of the retail sector.


PEDIATRICS ◽  
1962 ◽  
Vol 30 (2) ◽  
pp. 194-205
Author(s):  
Theodore C. Doege ◽  
Clark W. Heath ◽  
Ida L. Sherman

Diphtheria attack rates and cases, and to a much lesser extent case-fatality rates, have fallen steadily within the United States during the past 25 years. However, during 1959 and 1960 there was a halt in this long-term trend. Epidemiologic data on 868 clinical cases of diphtheria occurring in 1959 and 873 cases in 1960 were submitted to the Communicable Disease Center by 45 states. The cases and several major outbreaks tended to concentrate in the southern and southwestern states. Attack rates and deaths were highest for children under 10 years, and attack rates were more than five times greater for nonwhite children. Analysis of 1960 immunization data shows that 72% of the patients had received no immunizations. Fifty-five per cent of carriers, but only 18% of persons with bacteriologically confirmed cases, had received a primary series. Only 1 person of 58 fatal cases occurring in 1960 had received a primary series. Certain problems for future investigation, disclosed by the surveillance data, are discussed.


2020 ◽  
pp. 345-394
Author(s):  
Jerome Slater

This chapter begins with extended summary of the main arguments of this book, especially that Israel has missed or refused a number of opportunities to settle the Arab-Israeli conflict. Almost all the wars could have been avoided if Israel had agreed to fair compromises. The second half of this chapter examines possible solutions to the conflict, arguing that the standard two-state solution is dead. Various proposed alternatives, such as a binational single Israeli-Palestine state, are either impractical or undesirable. A mini-Palestinian state is proposed—a “Luxembourg solution”—and the reasons that it could prove acceptable to both sides are examined. If Israel refuses, the United States should employ both pressures and incentives to overcome its opposition. The national interest of the United States in the Middle East is reviewed, in the past and today. The pros and cons of offering Israel a formal mutual defense treaty in the context of a political settlement with the Palestinians are explored.


2020 ◽  
Vol 6 (23) ◽  
pp. eaba2937 ◽  
Author(s):  
Stefan Leyk ◽  
Johannes H. Uhl ◽  
Dylan S. Connor ◽  
Anna E. Braswell ◽  
Nathan Mietkiewicz ◽  
...  

Over the past 200 years, the population of the United States grew more than 40-fold. The resulting development of the built environment has had a profound impact on the regional economic, demographic, and environmental structure of North America. Unfortunately, constraints on data availability limit opportunities to study long-term development patterns and how population growth relates to land-use change. Using hundreds of millions of property records, we undertake the finest-resolution analysis to date, in space and time, of urbanization patterns from 1810 to 2015. Temporally consistent metrics reveal distinct long-term urban development patterns characterizing processes such as settlement expansion and densification at fine granularity. Furthermore, we demonstrate that these settlement measures are robust proxies for population throughout the record and thus potential surrogates for estimating population changes at fine scales. These new insights and data vastly expand opportunities to study land use, population change, and urbanization over the past two centuries.


2006 ◽  
Vol 4 (8) ◽  
pp. 751-757 ◽  
Author(s):  
Laura M. Kulik

Chronic inflammation induced by viral infections and their role in carcinogenesis is well recognized. Two hepatotropic viruses, hepatitis B and hepatitis C (HCV), have been linked worldwide to the development of hepatocellular carcinoma (HCC). Although orthotopic liver transplant offers the best chance for cure and long-term survival, the demand for organs far outweighs the supply. The incidence of HCC in the United States has increased over the past 3 decades. HCV-induced cirrhosis is believed to play a significant role in the rising rate of HCC. Therefore, primary measures to prevent HCC in HCV-infected patients are urgently needed. Numerous studies of the HCV HCC patient have considered primary treatment with interferon-based therapy. However, secondary prevention currently seems to carry more promise. This article evaluates and assesses various treatments for primary and secondary chemoprevention in the setting of HCV.


2020 ◽  
Vol 12 (3) ◽  
pp. 35-45
Author(s):  
M. A. Savchenko ◽  
A. M. Panteleev

Over the past decade, in Russian Federation there has been a steady increase in the incidence of MAC-infection in patients with HIV (the growth of nosology over the past five years, on average, was 57% per year). This determines the interest in this problem, especially in terms of the high inefficiency of treatment for the disease, the long term and cost of treatment. The history of the study of Mycobacterium Avium Complex-infection (MAC) originates in the early eighties in the United States, when the prognosis for a patient with AIDS and mycobacteriosis was extremely poor: mortality within one year after the detection of pathogen reached 71%. The role of infection in the thanatogenesis of patients was, however, established only by the beginning of the nineties. The detection of macrolide activity against the pathogen significantly improved the prognosis for patients, especially in combination with highly active antiretroviral therapy. The widespread introduction of antiviral drugs into practice and the ability to achieve immune reconstitution prevented the development of opportunistic infections, but did not solve the remaining issues of the treatment of the MAC-infection. The main one is the treatment of patients with a clarithromycin-resistant pathogen. There is no consensus on the sensitivity of non-tuberculous mycobacteria to antibacterials.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4866-4866
Author(s):  
Justine M. Kahn ◽  
Theresa H.M. Keegan ◽  
Elysia Alvarez ◽  
Lori S Muffly ◽  
Helen Parsons ◽  
...  

Abstract Background: Hodgkin lymphoma (HL) is one of the most common, and one of the most curable cancers in adolescents and young adults (AYAs) (15-39 years). Despite excellent outcomes in the majority of patients, the burden of long-term morbidity and mortality persists. Prior analyses of patients treated for HL before the year 2000 have reported mortality rates as high as 30% by 20 years. Further, this mortality risk has historically differed across different racial and ethnic groups. Over the past decade, cooperative groups have expanded the use of risk-adapted, response-based treatment in an effort to maintain high cure rates, while simultaneously reducing the burden of late effects. We examined long-term survival in AYAs with HL treated after the year 2000. Methods: We used the National Cancer Institute Surveillance, Epidemiology, and End Results registry data for 18 regions in the United States (SEER18) to examine survival in AYAs with a confirmed diagnosis of HL between 2000 and 2015. We obtained overall and cause-specific survival estimates for each year after cancer diagnosis (up to 15 years) for each racial/ethnic group with corresponding 95% confidence intervals. From these yearly survival estimates, we calculated the percentage of deaths not attributed to HL at 10- and 15-years after cancer diagnosis. Results: The final analysis included 16,868 HL patients. Racial/ethnic subgroups included: non-Hispanic white (NHW; 11,016, 65%), Hispanic (2,753, 16%), non-Hispanic black (NHB; 2,131, 13%), and Asian/Pacific Islander (API; 968, 6%) AYAs with HL. Across the full cohort, the 10-year and 15-year overall survival probabilities were 90% (95% confidence interval [95%CI]: 89 - 91) and 87% (95% CI: 86 - 88), respectively. At 10- and 15-years, overall survival was highest for NHWs (10-year: 92%: 15-year: 88%) and APIs (91%; 86%) compared to Hispanics (87%; 85%) and NHBs (82%; 78%). Overall survival, cause-specific survival, and percentage of deaths not attributed to HL by race/ethnicity are presented in the Figure. In the first year after diagnosis, 22% of deaths were due to causes other than primary disease, with the percentage of deaths not attributed to HL higher in NHWs and APIs than Hispanics and NHBs. At most time points after cancer diagnosis, a higher proportion of NHW (vs. NHB, Hispanic and API) patients died from causes other than HL. By 10 years after diagnosis, 25% of NHW patients died due to causes other than HL, vs. 20% in API, 17% in NHB, and 15% in Hispanic patients. By 15 years, 33% of all deaths were not attributed to HL. This was observed most dramatically in the NHW cohort in whom 40% of all deaths were not HL-related, compared to 24% of deaths in the NHB cohort and 26% - 27% of deaths in the Hispanic and API groups. Conclusion: In AYAs diagnosed with HL between 2000 and 2015, NHB patients had worse survival compared with NHW and API patients. The higher probability of survival in NHW patients was accompanied by a consistently higher proportion of non-cancer related death in this cohort both 10- years and 15-years after diagnosis. Studies are needed to evaluate risk factors for both short- and long-term mortality in AYAs, and to examine how these risks differ across racial/ethnic groups. Findings also suggest that despite increasing use of response-adapted therapy over the past two decades, all AYAs with HL remain at risk of death in the decades following therapy, further highlighting the need for long-term follow-up of this at-risk patient population. Figure. Figure. Disclosures Muffly: Adaptive Biotechnologies: Research Funding; Shire Pharmaceuticals: Research Funding.


2012 ◽  
Vol 19 ◽  
pp. 23
Author(s):  
Ashley Flint

Health care spending in the United States has increased rapidly over the past several decades. Medicare, the largest public health insurance program in the US, is a key component of these growing costs. While Medicare financing is expected to be stable over the next decade, the long-term solvency will be difficult to sustain absent congressional action. This paper analyzes three policy options for Congress to consider in addressing the problem of rapid cost growth in the Medicare program.


Author(s):  
Fabio Costa ◽  
Francesco Saverio Ambesi-Impiombato ◽  
Tommaso Beccari ◽  
Carmela Conte ◽  
Samuela Cataldi ◽  
...  

Space travel is an extreme experience even for the astronaut who has received extensive basic training in various fields, from aeronautics to engineering, from medicine to physics and biology. Microgravity puts a strain on members of space crews, both physically and mentally: short-term or long-term travel in orbit the International Space Station may have serious repercussions on the human body, which may undergo physiological changes affecting almost all organs and systems, particularly at the muscular, cardiovascular and bone compartments. This review aims to highlight recent studies describing damages of human body induced by the space environment for microgravity, and radiation. All novel conditions, to ally unknown to the Darwinian selection strategies on Earth, to which we should add the psychological stress that astronauts suffer due to the inevitable forced cohabitation in claustrophobic environments, the deprivation from their affections and the need to adapt to a new lifestyle with molecular changes due to the confinement. In this context, significant nutritional deficiencies with consequent molecular mechanism changes in the cells that induce to the onset of physiological and cognitive impairment have been considered.


2020 ◽  
Vol 10 (12) ◽  
pp. 4309
Author(s):  
Marina Fava ◽  
Alessandro Leuti ◽  
Mauro Maccarrone

Since the first Apollo mission in 1969, microgravity has been linked to many alterations of astronauts’ physiology, among which immunosuppression, altered inflammation and bone loss represent relevant examples. In the past 40 years, extensive investigations have been conducted in order to characterize the molecular mechanisms driving the alterations caused by prolonged weightlessness on human health. However, almost all studies eluded the role played by bioactive lipids, a vastly heterogeneous class of endogenous molecules, which, under normal conditions, control immune and bone homeostasis. This is somewhat surprising, because it is widely accepted that pathological derangement of the production or signalling of these endogenous compounds leads to the onset and/or progression of numerous diseases. In particular, eicosanoids and endocannabinoids are known to play a role in immune responses and bone remodelling. Both classes represent the only lipids as yet investigated in Space, and are increasingly recognised as promising therapeutic candidates to combat different human disorders. This review summarizes evidence gathered in the past two decades on the changes in these two pivotal lipid signalling systems, through both simulated and authentic weightlessness (i.e., on board the International Space Station and in parabolic flights).


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