Publications by authors named "Yan G Zorbas"

Studies have shown that chronic periodic fluid shifting upwards is not sensed as excessive fluid volume and excretion mechanisms are not activated. To determine if chronic periodic fluid and volume shifting upwards can affect muscle calcium (Ca(2+)) during hypokinesia (HK) we measured muscle Ca(2+) content, plasma Ca(2+) concentration, and Ca(2+) losses in urine and feces. Studies were conducted on 40 healthy male volunteers.

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Objectives: Microelement supplementation during Hypokinesia (HK; diminished movement) affects differently microelement metabolism from that of normal muscular activity. In view of the effect of trace element supplementation and HK upon microelement metabolism we investigated the effect of vanadium (V) supplements on tissue V content and V loss during HK.

Methods: Studies were performed on 240 male Wistar rats during a pre-experimental period of 9 days and an experimental period of 98 days.

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Objective: The incompleteness of electrolyte utilization during hypokinesia and electrolyte supplementation is the defining factor of electrolyte metabolic changes, yet the effect of electrolyte supplementation and HK upon electrolyte utilization is poorly understood. To determine the influence of magnesium (Mg(2+)) supplementation and hypokinesia (diminished movement) on magnesium utilization, we investigated the use of Mg(2+) supplementation to establish its effect upon muscle Mg(2+) content and Mg2(2+) losses.

Methods: This study was conducted in 40 physically healthy male volunteers during a pre-experimental period of 30 d and an experimental period of 364 d.

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Objective: To determine whether during hypokinesia (diminished movement) periodic physical exercise affects calcium (Ca(2+)) balance and Ca(2+) loss.

Methods: Studies were conducted on 30 physically healthy male volunteers during the preexperimental period of 30 days and the experimental period of 364 days. They were equally divided into three groups: active control subjects (ACS), hypokinetic subjects (HKS), and periodic training subjects (PTS).

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Objective: To determine the effect of potassium (K+) supplementation and hypokinesia (HK; diminished movement) on muscle K+ content and K+ loss.

Methods: Studies were conducted on 40 healthy male volunteers during a pre-experimental period of 30 days and an experimental-period of 364 days. Volunteers were equally divided into four groups: unsupplemented control subjects (UCS), unsupplemented experimental subjects (UES), supplemented control subjects (SCS), and supplemented experimental subjects (SES).

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Background: We undertook this study to determine total calcium (Ca(2+)) loss in Ca(2+)-deficient tissue and tissue Ca(2+) loss with and without Ca(2+) supplementation during hypokinesia (HK; diminished movement).

Methods: Studies were conducted on 240 male Wistar rats during a pre-experimental period of 9 days and an experimental period of 98 days. Rats were equally divided into four groups: unsupplemented vivarium control rats (UVCR), unsupplemented hypokinetic rats (UHKR), supplemented vivarium control rats (SVCR), and supplemented hypokinetic rats (SHKR).

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This study aims at showing that during hypokinesia (HK) tissue magnesium (Mg2+) content decreases more with higher Mg2+ intake than with lower Mg2+ intake and that Mg2+ loss increases more with higher than lower tissue Mg2+ depletion due to inability of the body to use Mg2+ during HK. Studies were conducted on male Wistar rats during a pre-HK period and a HK period. Rats were equally divided into four groups: unsupplemented vivarium control rats (UVCR), unsupplemented hypokinetic rats (UHKR), supplemented vivarium control rats (SVCR) and supplemented hypokinetic rats (SHKR).

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Objective: We investigated the effect of hypokinesia (diminished movement) on muscle calcium (Ca(2+)) content with and without Ca(2+) supplementation and Ca(2+) loss with different muscle Ca(2+) deficiency; muscle Ca(2+) content, plasma Ca(2+) level, and Ca(2+) loss were measured.

Methods: Studies were performed in 40 physically healthy male volunteers during a pre-experimental period of 30 d and an experimental period of 364 d. Subjects in equal numbers were assigned to one of four groups: unsupplemented active control subjects (UACSs), unsupplemented hypokinetic subjects (UHKSs), supplemented active control subjects (SACSs), and supplemented hypokinetic subjects (SHKSs).

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Objective: This study aimed to show that during hypokinesia (HK), phosphate (P(i)) imbalance increases more with higher than lower physical activity and that P(i) absorption reduces more with higher than lower P(i) imbalance in subjects with higher than lower muscular activity.

Methods: Studies were conducted on 30 healthy male subjects during 364 days of HK. They were equally divided in three groups: unrestricted active control subjects (UACS), continuously hypokinetic subjects (CHKS) and periodically hypokinetic subjects (PHKS).

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To demonstrate the effect of sodium supplementation and hypokinesia (HK; diminished movement) on the total bodily sodium (Na+) loss and tissue Na+ deficiency, tissue Na+ content, plasma Na+ level and Na+ loss were measured. Studies were conducted on male Wistar rats during a pre-experimental and experimental period. Animals were equally divided into four groups: unsupplemented vivarium control rats (UVCR), unsupplemented hypokinetic rats (UHKR), supplemented vivarium control rats (SVCR) and supplemented hypokinetic rats (SHKR).

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The objective of this study was to show that hypokinesia (diminished movement) could affect differently water and electrolyte content in muscles having minimum differences in their function and morphology. To this end, we studied water and electrolyte content in skeletal and cardiac muscles, fluid excretion, electrolyte absorption, and electrolyte levels in plasma, urine and feces of rats during prolonged hypokinesia (HK). Studies were conducted on one-hundred-twenty-six 13-weeks old male Wister rats during a pre-hypokinetic period and a hypokinesia period.

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The aim of this study was to determine that hypokinesia (restricted motor activity) could increase potassium (K+) losses with decreased tissue K+ content showing decreased K+ deposition. To this end, measurements were made of K+absorption, tissue K+ content, plasma K+ levels, fecal and urinary K+ excretion during and after hypokinesia (HK) with and without K+ supplementation. Studies conducted on male Wistar rats during a pre-hypokinetic period, a hypokinetic period and a post-hypokinetic period.

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Measuring potassium (K+) absorption, and K+ levels in plasma, urine and feces during and after hypokinesia (HK) and K+ supplementation, the aim of this study was to determine if prolonged HK could depress K+ deposition significantly more with or without K+ supplementation. Studies were conducted during 30-days pre-HK, 364-days HK and 30-days post-HK. Forty male healthy volunteers 24.

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Measuring calcium (Ca) absorption, Ca balance and Ca level in serum,feces and urine during HK (hypokinesia) with and without Ca loading, the aim of this study was to disclose if prolonged HK could reduce Ca deposition more with or without Ca load contributing to greater Ca imbalance. Studies were conducted during 30-days pre-HK and 364-days HK. Forty male normal volunteers 23.

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Measuring intercompartmental, blood and urinary biochemical parameters during acute bed rest (ABR) and rigorous bed rest (RBR) the aim of this work was to disclose if ABR or RBR could influence significantly more and significantly faster the body hydration level in normal subjects. Studies conducted during pre-bed rest (BR) period of 3-days and during 7-days period of ABR and RBR. Thirty normal male individuals 24.

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Measuring fluid absorption and fluid homeostasis, the aim of this study was to establish if hypokinesia (HK) could depress fluid deposition and thus contribute to the development of fluid depletion. Studies were performed during 30 days pre-HK period and during 364 days HK period. Twenty healthy male individuals 24.

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Rigorous bed rest (RBR) induces fluid depletion, however, little is known about the mechanisms of development of fluid depletion during acute bed rest (ABR). Measuring fluid retention and body hydration parameters, the aim of this study was to establish whether ABR than RBR could depress significantly more fluid retention contributing to greater fluid depletion development. Studies were conducted during pre bed rest (BR) period of three days and during seven days period of ABR and RBR.

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Body fluid homeostasis undergoes significant changes during hypokinesia (diminished movement). Understanding of fluid transfer between body fluid compartments and its regulating mechanisms was the aim of this study for disclosing impaired fluid retention during hypokinesia (HK). Studies were done on 12 male Macaca mulatta (rhesus monkeys) aged three to five years (5.

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Hypokinesia (diminished movement) induces muscle mineral depletion. However, the mechanism of muscle mineral depletion during hypokinesia (HK) remains unknown. Measuring electrolyte retention and electrolyte values in muscle, plasma, and urine during and after HK, the aim of this study was to discover if HK could depress mineral retention and lead to muscle mineral depletion.

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Hypokinesia (diminished movement) induces phosphate (P) changes; however, it is not known if P change is greater in trained than untrained subjects. Measuring P balance and P retention during hypokinesia (HK) and P load, we studied if changes in P retention and P depletion were significantly (p<0.05) greater in trained than untrained subjects.

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Bed rest (BR) induces significant urinary and blood electrolyte changes, but little is known about the effect of fluid and salt supplements (FSS) on catabolism, hydration and electrolytes. The aim was to measure the effect of FSS on catabolism, body hydration and electrolytes during BR. Studies were done during 7 days of a pre-bed rest period and during 30 days of a rigorous bed rest period.

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Body hydration decreases significantly during hypokinesia (HK) (diminished movement), but little is known about the effect of fluid and salt supplements (FSS) on body hydration during HK. The aim of this study was to measure the effect of FSS on body hydration during HK. Studies were done during 30 days pre HK period and 364 days HK period.

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Rigorous bed rest (RBR) induces significant biochemical and circulatory changes. However, little is known about acute rigorous bed rest (ARBR). Measuring biochemical and circulatory variables during ARBR and RBR the aim of this study was to establish the significance of ARBR effect.

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Hypokinesia (diminished movement) induces significant magnesium (Mg) changes; however, little is known about Mg deposition and Mg depletion during HK. Measuring the Mg level in some tissues during HK and post-HK and Mg supplement, we aimed to establish Mg deposition and Mg depletion during prolonged HK. Studies were done on 408, 13-wk-old male Wistar rats (370-390 g) for a 15-d pre-HK period, a 98-d HK period, and a 15-d post-HK period.

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Hypokinesia (diminished movement) induces significant phosphate (P) excretion; however, little is known about the P deposition ability of the body during hypokinesia (HK). Using P loads, the aim of this study was to establish the deposition ability of the body to retain P during prolonged HK. Studies were done during a 30-d period of pre-HK and a 364-d period of HK.

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