On the combined effects of normobaric hypoxia and bed rest upon bone and mineral metabolism: Results from the PlanHab study

AbstractBone losses are common as a consequence of unloading and also in patients with chronic obstructive pulmonary disease (COPD). Although hypoxia has been implicated as an important factor to drive bone loss, its interaction with unloading remains unresolved. The objective therefore was to assess whether human bone loss caused by unloading could be aggravated by chronic hypoxia.In a cross-over designed study, 14 healthy young men underwent 21-day interventions of bed rest in normoxia (NBR), bed rest in hypoxia (HBR), and hypoxic ambulatory confinement (HAmb). Hypoxic conditions were equivalent to 4000m altitude. Bone metabolism (NTX, P1NP, sclerostin, DKK1) and phospho-calcic homeostasis (calcium and phosphate serum levels and urinary excretion, PTH) were assessed from regular blood samples and 24-hour urine collections, and tibia and femur bone mineral content was assessed by peripheral quantitative computed tomography (pQCT).Urinary NTX excretion increased (P<0.001) to a similar extent in NBR and HBR (P=0.69) and P1NP serum levels decreased (P=0.0035) with likewise no difference between NBR and HBR (P=0.88). Serum total calcium was increased during bed rest by 0.059 (day D05, SE 0.05mM) to 0.091mM (day D21, P<0.001), with no additional effect by hypoxia during bed rest (P=0.199). HAmb led, at least temporally, to increased total serum calcium, to reduced serum phosphate, and to reduced phosphate and calcium excretion.In conclusion, hypoxia did not aggravate bed rest-induced bone resorption, but led to changes in phospho-calcic homeostasis likely caused by hyperventilation. Whether hyperventilation could have mitigated the effects of hypoxia in this study remains to be established

Markers of bone metabolism during 14 days of bed rest in young and older men

OBJECTIVE: We aimed at comparing markers of bone metabolism during unloading in young and older men, and to assess countermeasure effectiveness. METHODS: 16 older (60\ub12 years) and 8 younger men (23\ub13 years) underwent bed rest (BR) for 14 days. A subgroup of the Older performed cognitive training during BR and supplemented protein and potassium bicarbonate afterwards. Biochemical markers of bone and calcium/phosphate metabolism were assessed. RESULTS: At baseline urinary NTX and CTX were greater in younger than in older subjects (P0.17). P1NP was greater in young than in older subjects (P<0.001) and decreased during BR in the Young (P<0.001). Sclerostin increased during BR across groups (P=0.016). No systematic effects of the countermeasure were observed. CONCLUSION: In men, older age did not affect control of bone metabolism, but bone turnover was reduced. During BR formation markers were reduced only in younger men whereas resorption markers increased to a comparable extent. Thus, we assume that older men are not at an elevated, and possibly even at a reduced risk to lose bone when immobilize

Application technology for cold-rolled and coated sheet products at Hoesch Stahl AG

Translated from German (Stahl Eisen 1988 v. 108(4) p. 153-159)Available from British Library Document Supply Centre- DSC:9022.06(BISI-Trans--27000)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Application technology for cold-rolled and coated sheet products at Hoesch Stahl AG

Translated from German (Stahl Eisen 1988 v. 108(4) p. 153-159)Available from British Library Document Supply Centre- DSC:9022.06(BISI-Trans--27000)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Weiterverarbeitung von verzinktem und beschichtetem Stahlblech

Im Mittelpunkt dieser Schriftenreihe steht die Weiterverarbeitung von Stahlblechen, die im Schmelztauch-, elektrolytischen oder Bandbeschichtungsverfahren veredelt werden. Dabei werden schwerpunktmaessig Umformen, Schweissen und mechanisches Fuegen behandelt. (MM)Information given in this publication focuses on the further processing of steel sheet that has been finished by the processes of hot-dip coating, electrolytic or strip coating. Aspects of main interest are forming, welding, or mechanical joining. (MM)SIGLEAvailable from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

The LunHab project: Muscle and bone alterations in male participants following a 10 day lunar habitat simulation

Musculoskeletal atrophy constitutes a typical adaptation to inactivity and unloading of weightbearing bones. The reduced-gravity environment in future Moon and Mars habitats is likely to be hypobaric hypoxic, and there is an urgent need to understand the effect of hypoxia on the process of inactivity-induced musculoskeletal atrophy. This was the principal aim of the present study. Eleven males participated in three 10 day interventions: (i) hypoxic ambulatory confinement; (ii) hypoxic bed rest; and (iii) normoxic bed rest. Before and after the interventions, the muscle strength (isometric maximal voluntary contraction), mass (lean mass, by dual-energy X-ray absorptiometry), cross-sectional area and total bone mineral content (determined with peripheral quantitative computed tomography) of the participants were measured. Blood and urine samples were collected before and on the 1st, 4th and 10th day of the intervention and analysed for biomarkers of bone resorption and formation. There was a significant reduction in thigh and lower leg muscle mass and volume after both normoxic and hypoxic bed rests. Muscle strength loss was proportionately greater than the loss in muscle mass for both thigh and lower leg. There was no indication of bone loss. Furthermore, the biomarkers of resorption and formation were not affected by any of the interventions. There was no significant effect of hypoxia on the musculoskeletal variables. Short-term normoxic (10 day) bed rest resulted in muscular deconditioning, but not in the loss of bone mineral content or changes in bone metabolism. Hypoxia did not modify these results

Markers of bone matebolism during 14 days of bed rest in young and older men

Objective: We aimed at comparing markers of bone metabolism during unloading in young and older men, and toassess countermeasure effectiveness. Methods: 16 older (60±2 years) and 8 younger men (23±3 years) underwentbed rest (BR) for 14 days. A subgroup of the Older performed cognitive training during BR and supplemented proteinand potassium bicarbonate afterwards. Biochemical markers of bone and calcium/phosphate metabolism were assessed.Results: At baseline urinary NTX and CTX were greater in younger than in older subjects (P0.17). P1NP was greater in young than in older subjects (P<0.001) and decreasedduring BR in the Young (P<0.001). Sclerostin increased during BR across groups (P=0.016). No systematic effects ofthe countermeasure were observed. Conclusion: In men, older age did not affect control of bone metabolism, but boneturnover was reduced. During BR formation markers were reduced only in younger men whereas resorption markersincreased to a comparable extent. Thus, we assume that older men are not at an elevated, and possibly even at a reducedrisk to lose bone when immobilized.Fil: Buehlmeier, J.. Institute of Aerospace Medicine; Alemania. Universitat Bonn; AlemaniaFil: Frings Meuthen, P.. Institute of Aerospace Medicine; AlemaniaFil: Mohorko, N.. University of Primorska; EsloveniaFil: Lau, P.. Institute of Aerospace Medicine; AlemaniaFil: Mazzucco, S.. University Trieste; ItaliaFil: Ferretti, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Biolo, G.. University Trieste; ItaliaFil: Pisot, R.. University of Primorska; EsloveniaFil: Simunic, B.. University of Primorska; EsloveniaFil: Rittweger, J.. Institute of Aerospace Medicine; Alemani

T2-relaxation time increases in lumbar intervertebral discs after 21d head-down tilt bed-rest

Objectives: Spaceflight back pain and intervertebral disc (IVD) herniations cause problems in astronauts. Purpose of this study was to assess changes in T2-relaxation-time through MRI measurements before and after head-down tilt bed-rest, a spaceflight analog. Methods: 8 men participated in the bed-rest study. Subjects remained in 6 degrees head down tilt bed-rest in two campaigns of 21 days, and received a nutritional intervention (potassium bicarbonate 90 mmol/d) in a cross-over design. MRI measurements were performed 2 days before bed-rest, as well as one and five days after getting up. Image segmentation and data analysis were conducted for the IVDs Th12/L1 to L5/S1. Results: 7 subjects, average age of 27.6 (SD 3.3) years, completed the study. Results showed a significant increase in T2-time in all IVDs (p < 0.001), more pronounced in the nucleus pulposus than in the annulus fibrosus (p< 0.001). Oral potassium bicarbonate did not show an effect (p=0.443). Pfirrmann-grade correlated with the T2-time (p< 0.001). Conclusions: 6 degrees head-down tilt bed-rest leads to a T2-time increase in lumbar IVDs. Oral potassium bicarbonate supplementation does not have an effect on IVD T2-time