| 21. |
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| 22. |
- Jansson, John-Olov, 1954, et al.
(författare)
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A Body Weight Sensor Regulates Prepubertal Growth via the Somatotropic Axis in Male Rats
- 2021
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Ingår i: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 162:6
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Tidskriftsartikel (refereegranskat)abstract
- In healthy conditions, prepubertal growth follows an individual specific growth channel. Growth hormone (GH) is undoubtedly the major regulator of growth. However, the homeostatic regulation to maintain the individual specific growth channel during growth is unclear. We recently hypothesized a body weight sensing homeostatic regulation of body weight during adulthood, the gravitostat. We now investigated if sensing of body weight also contributes to the strict homeostatic regulation to maintain the individual specific growth channel during prepubertal growth. To evaluate the effect of increased artificial loading on prepubertal growth, we implanted heavy (20% of body weight) or light (2% of the body weight) capsules into the abdomen of 26-day-old male rats. The body growth, as determined by change in biological body weight and growth of the long bones and the axial skeleton, was reduced in rats bearing a heavy load compared with light load. Removal of the increased load resulted in a catch-up growth and a normalization of body weight. Loading decreased hypothalamic growth hormone releasing hormone mRNA, liver insulin-like growth factor (IGF)-1 mRNA, and serum IGF-1, suggesting that the reduced body growth was caused by a negative feedback regulation on the somatotropic axis and this notion was supported by the fact that increased loading did not reduce body growth in GH-treated rats. Based on these data, we propose the gravitostat hypothesis for the regulation of prepubertal growth. This states that there is a homeostatic regulation to maintain the individual specific growth channel via body weight sensing, regulating the somatotropic axis and explaining catch-up growth.
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| 23. |
- Jansson, John-Olov, 1954, et al.
(författare)
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Body weight homeostat that regulates fat mass independently of leptin in rats and mice.
- 2018
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 115:2, s. 427-432
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Tidskriftsartikel (refereegranskat)abstract
- Subjects spending much time sitting have increased risk of obesity but the mechanism for the antiobesity effect of standing is unknown. We hypothesized that there is a homeostatic regulation of body weight. We demonstrate that increased loading of rodents, achieved using capsules with different weights implanted in the abdomen or s.c. on the back, reversibly decreases the biological body weight via reduced food intake. Importantly, loading relieves diet-induced obesity and improves glucose tolerance. The identified homeostat for body weight regulates body fat mass independently of fat-derived leptin, revealing two independent negative feedback systems for fat mass regulation. It is known that osteocytes can sense changes in bone strain. In this study, the body weight-reducing effect of increased loading was lost in mice depleted of osteocytes. We propose that increased body weight activates a sensor dependent on osteocytes of the weight-bearing bones. This induces an afferent signal, which reduces body weight. These findings demonstrate a leptin-independent body weight homeostat ("gravitostat") that regulates fat mass.
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| 24. |
- Jansson, John-Olov, 1954, et al.
(författare)
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The dual hypothesis of homeostatic body weight regulation, including gravity-dependent and leptin-dependent actions.
- 2023
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Ingår i: Philosophical transactions of the Royal Society of London. Series B, Biological sciences. - 1471-2970. ; 378:1888
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Forskningsöversikt (refereegranskat)abstract
- Body weight is tightly regulated when outside the normal range. It has been proposed that there are individual-specific lower and upper intervention points for when the homeostatic regulation of body weight is initiated. The nature of the homeostatic mechanisms regulating body weight at the lower and upper ends of the body weight spectrum might differ. Previous studies demonstrate that leptin is the main regulator of body weight at the lower end of the body weight spectrum. We have proposed that land-living animals use gravity to regulate their body weight. We named this homeostatic system the gravitostat and proposed that there are two components of the gravitostat. First, an obvious mechanism involves increased energy consumption in relation to body weight when working against gravity on land. In addition, we propose that there exists a component, involving sensing of the body weight by osteocytes in the weight-bearing bones, resulting in a feedback regulation of energy metabolism and body weight. The gravity-dependent homeostatic regulation is mainly active in obese mice. We, herein, propose the dual hypothesis of body weight regulation, including gravity-dependent actions (= gravitostat) at the upper end and leptin-dependent actions at the lower end of the body weight spectrum. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part II)'.
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| 25. |
- Kihlberg, Steve, et al.
(författare)
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Arbete och Hälsa
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- En ergonomisk och teknisk utvärdering genomfördes av en förändring av produktionssystemet i ett elektronikföretag som innebar en ökad automatisering. Själva förändringsprocessen utvärderades också.Automatiseringen av den manuella monteringen och transporten minskade exponeringstiden för manuell montering på systemnivå samt ökade produktiviteten. För den kvarstående manuella monteringen ökade dock repetitiviteten och ensidigheten. Montörerna upplevde också att den psykiska arbetsbelastningen var större i det nya systemet jämfört med det gamla. De ansåg också att de manuella monteringsstationerna som helhet var dåliga arbetsuppgifter.I den studerade förändringsprocessen var bristen på kontinuitet i arbetsledning ett av avdelningens huvudproblem. Arbetsledaren fick också sätta sin prägel på hur produktionsmålen skulle uppfyllas och hur arbetsförhållandena skulle utformas. Därigenom blev det arbetsledaren och inte den handlingsplan med arbetsrotation som en arbetsorganisationsgrupp utformade som avgjorde hur arbetsorganisationen utformades.
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| 26. |
- Kihlberg, Steve, et al.
(författare)
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Ett produktionssystem under förändring - ergonomisk och teknisk utvärdering
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- En ergonomisk och teknisk utvärdering genomfördes av en förändring av produktionssystemet i ett elektronikföretag som innebar en ökad automatisering. Själva förändringsprocessen utvärderades också. Automatiseringen av den manuella monteringen och transporten minskade exponeringstiden för manuell montering på systemnivå samt ökade produktiviteten. För den kvarstående manuella monteringen ökade dock repetitiviteten och ensidigheten. Montörerna upplevde också att den psykiska arbetsbelastningen var större i det nya systemet jämfört med det gamla. De ansåg också att de manuella monteringsstationerna som helhet var dåliga arbetsuppgifter. I den studerade förändringsprocessen var bristen på kontinuitet i arbetsledning ett av avdelningens huvudproblem. Arbetsledaren fick också sätta sin prägel på hur produktionsmålen skulle uppfyllas och hur arbetsförhållandena skulle utformas. Därigenom blev det arbetsledaren och inte den handlingsplan med arbetsrotation som en arbetsorganisationsgrupp utformade som avgjorde hur arbetsorganisationen utformades.
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| 27. |
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| 28. |
- Lind, Mikael, et al.
(författare)
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Punctuality as performance metrics for efficient transportation systems
- 2014
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Ingår i: 21st World Congress on Intelligent Transport Systems, ITSWC 2014. - : Intelligent Transport Systems (ITS).
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Konferensbidrag (refereegranskat)abstract
- Transportation systems are ecosystems building on a high degree of co-production of value performed by multiple actors. In order to guide involved actors and ensure expected performance it becomes necessary to have an agreed performance metrics. Beside operational capacity for the transportation systems as such it is believed that punctuality as a performance metrics would be a solid base enabling different actors to take appropriate actions in planning, realizing, and evaluating their actions in relation to the expectations among involved actors (including beneficiaries) of the transportation system. In this paper, underlying mechanisms for punctuality are explored as the basis for an efficient transportation system.
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| 29. |
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| 30. |
- Lundberg, Ulf, et al.
(författare)
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Arbetsmiljöns betydelse för ryggproblem : En systematisk litteraturöversikt
- 2014
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Rapport (refereegranskat)abstract
- The Swedish Council on Health Technology Assessment (SBU) conducted a systematic literature review of research on the association between occupational exposures and back disorders. In this review, we use back disorders as an umbrella term to include the more specific terms back trouble (a subjective experience of pain, ache or discomfort in the back), symptoms of sciatica, intervertebral disc changes and diseases of the back. The report is focused on disorders of the thoracic and lumbar spine. A wide range of occupational exposures were investigated, including: physical work load, vibration, organizational and psychosocial factors, chemical and biological factors, noise, environmental factors and contagious substances.Background: Since 2011 SBU has had a mandate from the Swedish government to systematically assess the evidence associating occupational exposures to health issues. The objective of this review was to assess the scientific basis describing the influence of occupational exposures on back disorders. Back disorders are common. Between 60 and 70 percent of the general population world-wide suffer from back pain at least once in their life. For affected individuals, back disorders are the source of both suffering and decreased functioning. The costs to society are also considerable in terms of direct health care costs, financial support to individuals with work disability, as well as costs due to loss of production.Method: A systematic review was undertaken following the PRISMA statement and standard methods used by SBU adapted to an occupational context. A literature search covering years 1980 to January 2014 was conducted in international medical and occupational data bases. The review assessed almost 8 000 abstracts. Studies that fulfilled strict inclusion criteria were assessed for relevance and quality, using pre-set protocols. Relevance and quality assessments were conducted by two experts, working in an evaluation pair. After conducting independent assessments, the two experts had to agree on a mutual relevance and quality classification. Some articles required that all exporters participated in discussion and made a collective assessment. A total of 109 studies were classified as moderate or high quality, representing more than 150 000 study participants. The strength of the scientific evidence was assessed with the GRADE system.Results: There is an association between occupational exposure and back disorders. This result is based on investigations of a large variety of work environments, mainly in Europe and North America. In most studies passing the quality criteria, researchers investigated occupational exposure and back disorders in populations consisting of both women and men with at least one year of follow up.Conclusions: People in the following groups develop more back trouble over time than those who are not subjected to the specified exposure at work:– Those who work with manual handling (e.g. lift) or in a posture where the back is bent or rotated– Those who work in a kneeling or squatting posture, or have physically demanding work tasks– Those exposed to whole body vibration– Those who experience work as mentally stressful; or those who find their work demanding, but lack decision latitude (personal control of their own working situation); or those who have insufficient opportunities for personal development– Those who work outside standard office hours.In some work environments, people have less back trouble. Those who experience high influence over work-related decisions, those who get social support at work and those with high job satisfaction develop less back trouble than others.Women and men with similar occupational exposures develop back troubles to the same extent.Those who work in forward bent postures or are exposed to whole body vibration in their work develop more symptoms of sciatica than others, while those with high job satisfaction develop less such symptoms. Those whose work entails manual handling develop more intervertebral disc changes than others.This systematic literature review has uncovered a substantial body of knowledge concerning occupational exposures and back disorders. Future research should include intervention studies, i.e. studies that scientifically test the effect of well defined interventions on back disorders over extended periods of time in authentic work situations.Project groupExperts: Karin Harms-Ringdahl (Chair), Sven Ove Hanson (Ethics), Olle Hägg, Ulf Lundberg, Svend Erik Mathiasen, Gunnevi Sundelin, Magnus Svartengren, and Hans Tropp.SBU: Charlotte Hall (Project Director), Karin Stenström (Assistant Project Director), Agneta Brolund (Information Specialist), Therese Kedebring (Project Administrator), Laura Lintamo (Investigator), Maria Skogholm (Project Administrator), Lena Wallgren (Scientific Writer)Scientific reviewers: Eva Denison, Mats Hagberg, Gunnar Nemeth, Esa-Pekka Takala.
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