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1.
The effects of zinc deficiency and supplementation on plasma leptin levels were studied in Sprague-Dawley rats. After 6 wk
on a zinc-deficient diet containing 0.65 ppm Zn/g, the mean body weight was significantly lower than that of normal or zinc-supplemented
rats, which showed no difference among them. The plasma leptin and zinc levels were lowest in zinc-deficient animals and highest
in those that received a normal diet and daily intraperitioneal injections of 3 mg Zn/kg. These results indicate that zinc
deficiency leads to a significant inhibition in plasma leptin levels, whereas zinc supplementation significantly increases
plasma leptin. 相似文献
2.
Yan G. Zorbas Yuri Y. Yaroshenko Nikolai K. Kuznetsov Sergei L. Matvedev 《Biological trace element research》1998,64(1-3):259-273
The aim of this study was to evaluate the effect of a daily intake of fluid and salt supplementation (FSS) on the deficiency
of electrolytes, which is characterized by higher rather than lower plasma concentration of electrolytes during prolonged
hypokinesia (HK) (decreased number of km taken per day). Forty long distance runners aged 22–25 yr with a peak V02 65.4 mL min-1 kg-1 with an average 14.2 km d running distance were selected as subjects. They were equally divided into four groups: 1) unsupplemented
control subjects (UCS); 2) unsupplemented hypokinetic subjects (UHS); 3) supplemented hypokinetic subjects (SHS), and 4) supplemented
control subjects (SCS). During the investigation of 364 d, groups 2 and 3 maintained an average running distance of less than
4.7 km per day, groups 1 and 4 did not experience any modification in their normal training routines and diets. During the
preexperimental period of 60 d and during the experimental period of 364 d urinary excretion of electrolytes and concentrations
of sodium, potassium, calcium, and magnesium in plasma were determined. Whole blood hemoglobin, hematocrit index, plasma osmolality,
and plasma protein concentration were measured. In the UHS plasma concentration of electrolytes and urinary excretion thereof,
fluid elimination, hematocrit, whole blood hemoglobin, plasma osmolality, and plasma protein concentration increased significantly
(p < 0.05) when compared with the UCS, SCS, and SHS groups. In the SHS plasma concentration of electrolytes and urinary excretion
thereof, fluid excretion, whole blood hemoglobin, hematocrit, plasma osmolality, and plasma protein concentration decreased
when compared with the UHS and increased insignificantly when compared with the UCS and SCS groups. It was concluded that
FSS may be used to prevent or minimize electrolyte deficiency in endurance-trained volunteers during prolonged restriction
of muscular activity. 相似文献
3.
The aim of this study was to investigate how zinc deficiency and supplementation affects lipid peroxidation in the renal tissue
in ovariectomized rats. Four study groups were formed with 10 Spraque-Dawley rats each. Two of the groups served as normal
and ovariectomized controls; the other two were ovariectomized rats that were zinc deficient and zinc supplemented, respectively.
The zinc-deficient ovariectomized rats showed greater renal and plasma lipid peroxidation, as indicated by higher malondialdehyde
levels than all other groups (p<0.05). These values were higher in the ovariectomized controls than those of the normal controls and of the ovariectomized,
zinc-supplemented groups (p<0.05), which, in, turn, showed no significant differences of their respective renal and plasma malondialdehyde values.
The renal and erythrocyte glutathione levels in the zinc-supplemented rats were higher than those in all other groups (p<0.05). The zinc-deficient group had the lowest renal and erythrocyte glutathione levels (p<0.05). The renal tissue zinc levels in the ovariectomized rats were higher than those in the zinc-deficient animals, but
lower than in the normal controls and zincsupplemented rats (p<0.05). The zinc-supplemented animals had the highest renal tissue zinc levels (p<0.05).
The results of this study suggest that zinc deficiency increases renal tissue damage in ovariectomized rats and that zinc
supplementation can be used to prevent this condition. 相似文献
4.
Yan G. Zorbas Andrei G. Kakurin Nikolai K. Kuznetsov Maxim A. Federov Yuri Y. Yaroshenko 《Biological trace element research》1998,63(2):149-166
The aim of this study was to evaluate the effect of magnesium (Mg) loading (10.0 mg Mg/kg body wt) and daily Mg supplements
(5.0 mg Mg/kg body wt) on Mg deficiency shown by increased and not by decreased serum Mg concentration during hypokinesia
(decreased km number/d).
The studies were done during 30 d of prehypokinesia and 364 d of hypokinesia (HK) periods. Forty endurance-trained volunteers
aged 22–26 yr with a peak VO2 max of 66.3 mL·kg−1 min−1 and with an average 15.0 km/d running distance were chose as subjects. They were equally divided into four groups:
The SHKS and SACS groups took daily 5.0 mg elemental Mg/kg body wt and subjected to Mg loading (10.0 mg Mg/kg body wt). Both
the SHKS and UHKS groups were maintained under an average running distance of 4.7 km/d, whereas the SACS and UACS groups did
not experience any modifications to their normal training routines and diets.
During the prehypokinetic and hypokinetic periods, excretion of Mg in feces and urine, concentration of Mg in serum, and Mg
balance were measured. urinary and serum sodium (Na), potassium (K), and calcium (Ca) were also determined. In both SHKS and
UHKS groups, fecal Mg loss, urinary excretion of electrolytes, and serum concentrations of electrolytes increased significantly
(p≤0.05) when compared with the SACS and UACS groups. During Mg loading tests, urinary and fecal Mg excretion was also greater
in the SHKS and UHKS groups than in the SACS and UACS groups. Throughout the study, Mg balance was negative in the SHKS and
UHKS groups, whereas in the SACS and UACS groups, Mg balance was positive.
It was concluded that significant losses of Mg occurred in the presence of negative Mg balance and Mg deficiency in endurance-trained
subjects during prolonged exposure to HK, daily mg supplements, and Mg loading tests. This suggests that Mg is not entering
or being retaining by the bones and cells of many tissues where most Mg is deposited normally, resulting in Mg deficiency
as was shown by the increased serum Mg concentration. 相似文献
1. | Unsupplemented ambulatory control subjects (UACS). |
2. | Unsupplemented hypokinetic subjects (UHKS). |
3. | Supplemented hypokinetic subjects (SHKS). |
4. | Supplemented ambulatory control subjects (SACS). |
5.
Yan G. Zorbas Vassili G. Andreyev Grigori E. Veremtsov Youri N. Yaroshenko 《Biological trace element research》1997,58(1-2):103-116
The objective of this investigation was to determine whether a plentiful magnesium (Mg2+) supplementation might be used to normalize or prevent Mg deficiency. This is manifested by increased rather than decreased serum Mg2+ concentration as is observed during prolonged hospitalization, which is developed during prolonged hypokinesia (HK) (decreased motor activity). Eighty male Wistar rats with an initial body weight of 370–390 g were used to perform the studies: They were equally divided into four groups:
- Unsupplemented control animals (UCA);
- Supplemented control animals (SCA);
- Unsupplemented hypokinetic animals (UHA); and
- Supplemented hypokinetic animals (SHA).
6.
Yan G. Zorbas Kirill P. Charapakin Vassil J. Kakurin Nikolai K. Kuznetsov Maxim A. Federov Vladimir K. Popov 《Biological trace element research》1999,69(2):81-98
The aim of this study was to assess the effect of a daily intake of copper supplements on negative copper balance during prolonged
exposure to hypokinesia (decreased number of kilometers per day). During hypokinesia (HK), negative copper balance is shown
by increased, not by decreased, serum copper concentration, as it happens in other situations.
Studies were done during a 30-d prehypokinetic period and a 364-d hypokinetic period. Forty male trained volunteers aged 22–26
yr with a peak oxygen uptake of 66.4 mL/min/kg and with an average of 13.7 km/d running distance were chosen as subjects.
They were equally divided into four groups: unsupplemented ambulatory control subjects (UACS), unsupplemented hypokinetic
subjects (UHKS), supplemented hypokinetic subjects (SHKS), and supplemented ambulatory control subjects (SACS). The SACS and
SHKS groups took 0.09 mg copper carbonate/kg body weight daily. The SHKS and UHKS groups were maintained under an average
running distance of 1.7 km/d, whereas the SACS and UACS groups did not experience any modifications in their normal training
routines.
During the 30-d prehypokinetic period and the 346-d hypokinetic period, urinary excretion of copper, calcium, and magnesium
and serum concentrations of copper, calcium, and magnesium were measured. Copper loss in feces and copper balance was also
determined. In both UHKS and SHKS groups, urinary excretion of copper, calcium, and magnesium and concentrations of copper,
magnesium, and calcium in serum increased significantly when compared with the SACS and UACS groups. Loss of copper in feces
was also increased significantly in the SHKS and UHKS groups when compared with the UACS and SACS groups. Throughout the study,
the copper balance was negative in the SHKS and UHKS groups, whereas in the SACS and UACS groups, the copper balance was positive.
It was concluded that a daily intake of copper supplements cannot be used to prevent copper deficiency shown by increased
copper concentration. Copper supplements also failed to prevent negative copper balance and copper losses in feces and urine
in endurancetrained subjects during prolonged exposure to HK. 相似文献
7.
Yan G. Zorbas Vassil J. Kakurin Victor B. Afonin Nikolai A. Kuznetsov Vladimir L. Yarullin Sergei D. Denogradov 《Biological trace element research》1999,70(1):1-19
Negative potassium balance during hypokinesia (decreased number of kilometers taken/day) is not based on the potassium shortage
in the diet, but on the impossibility of the body to retain potassium. To assess this hypothesis, we study the effect of potassium
loading on athletes during prolonged hypokinesia (HK).
Studies were done during 30 d of a pre-HK period and during 364 d of an HK period. Forty male athletes aged 23–26 yr were
chosen as subjects. They were divided equally into four groups: unloaded ambulatory control subjects (UACS), unloaded hypokinetic
subjects (UHKS), loaded hypokinetic subjects (LHKS), and loaded ambulatory control subjects (LACS). For the simulation of
the hypokinetic effect, the LHKS and UHKS groups were kept under an average running distance of 1.7 km/d. In the LACS and
LHKS groups, potassium loading tests were done by administering 95.35 mg KC1 per kg body weight.
During the pre-HK and HK periods and after KC1 loading tests, fecal and urinary potassium excretion, sodium and chloride excretion,
plasma potassium, sodium and chloride concentration, and potassium balance were measured. Plasma renin activity (PRA) and
plasma aldosterone concentration was also measured. Negative potassium balance increased significantly (p < -0.01) in the UHKS and LHKS groups when compared with the UACS and LACS groups. Plasma electrolyte concentration, urinary
electrolyte excretion, fecal potassium excretion, PRA, and PA concentration increased significantly (p ≤ 0.01) in the LHKS
and UHKS groups when compared with LACS and UACS groups. Urinary and fecal potassium excretion increased much more and much
faster in the LHKS group than in the UHKS group. By contrast, the corresponding parameters change insignificantly in the UACS
and LACS groups when compared with the base line control values.
It was concluded that urinary and fecal potassium excretion increased significantly despite the presence of negative potassium
balance; thus, negative potassium balance may not be based on potassium shortage in the diet because of the impossibility
of the body to retain potassium during HK. 相似文献
8.
Yan G. Zorbas Nikolai A. Kuznetsov Youri N. Yaroshenko 《Biological trace element research》1997,57(2):169-181
The objective of this investigation was to determine the effect of prolonged restriction of motor activity (hypokinesia [HK])
on several parameters of water metabolism in primates. The studies were performed on 12 rhesus monkeys aged 4–5 yr (5.10–6.85
kg) during the hypokinetic period of 90 d and during the prehypokinetic period of 30 d. They were divided into two equal groups:
the first group was placed under ordinary vivarium conditions (vivarium control animals) and the second group was subjected
to 90 d of HK (hypokinetic animals). For the simulation of the hypokinetic effect, the primates were immobilized on their
abdomens in special tables. The legs of the monkeys were immobilized with hip and knee joints extended. The primates retained
freedom of movement at elbow, wrist, and ankle. During the preexperimental period of 30 d and during the experimental period
of 90 d, the following variables were determined: body weight, total body fluid content, specific total body fluid, mean fluid
consumed and eliminated in urine, specific plasma resistance, hematocrit level, and plasma concentrations of sodium (Na) and
potassium (K). In the hypokinetic primates, body weight decreased significantly when compared to the controls. Mean fluid
intake, total body fluid, and specific total body fluid decreased, whereas mean daily fluid loss and specific mean daily fluid
elimination increased significantly. Specific plasma resistance, hematocrit level, and plasma electrolyte concentrations increased
significantly when compared to the control primates. It was concluded that prolonged restriction of motor activity induces
significant changes in water metabolic parameters of primates leading in decreased total water content of the body. 相似文献
9.
Oztürk A Baltaci AK Bediz CS Mogulkoc R Güngör S 《Biological trace element research》2003,96(1-3):255-262
The present study was designed to investigate the effects of zinc and/or melatonin deficiency on rat testes. A total of 24
adult male Sprague-Dawley rats were used in this study. The rats were divided into four groups of six rats each, as follows:
(I) controls, (II) zinc deficient, (III) pinealectomized, zinc normal, and (IV) pinealectomized, zinc deficient. The plasma
zinc levels in the control group were higher than in all the other groups (p<0.01), and those of the zinc-deficient groups II and IV were significantly lower than for group III (p<0.01). The melatonin levels in the controls were also significantly higher than for all other groups (p<0.01) There was no significant difference in sperm production between the controls and the group of animals that had no epiphysis.
A significant suppression was observed in the spermatogenetic activity of the zinc-deficient groups (p<0.01). The suppression was higher in group II than in group IV. These results indicate that testicular damage caused by zinc
deficiency may be reduced by melatonin deficiency. 相似文献
10.
Summary Maize (Zea mays L. cv. Ganga-2) plants were grown in pot culture on a loamy alluvial soil of Lucknow district (India) alkalinized to graded
levels of ESP (Exchangeable Sodium Percentage) ranging from 15.5 to 55.3. Before sowing maize seeds the soil was fertilised
with NPK, Fe, Mn and Cu. At and above ESP 34 Zn-deficiency symptoms first appeared at 30 days. The symptoms gradually became
pronounced with increase in age and at 60 days they were found even at ESP 15.5. The severity of symptoms was related to increase
in sodicity. Alkalinization of soils depressed available soil Zn and tissue Zn and increased tissue ratios of Na/Zn and P/Zn.
It also decreased the total plant content of Zn, Fe, Mn, Cu and even Na. Increase in soil sodicity increased both tissue concentration
and total content of P in plants upto ESP 34 beyond which it decreased it. Among different extractants, 0.1N HCl, DTPA pH 7.3 and EDTA-(NH4)2 CO3 pH 8.6, for measuring available soil Zn the latter showed best correlations with soil ESP (−), tissue P (−), P/Zn ratio (−),
dry matter yield (+) and tissue Zn (+). Tissue Zn was related to yield (+), tissue Na (−) and soil ESP (−). Mild, moderate,
severe and very severe Zn deficiency in maize was induced by soil ESP levels, 18, 25, 33 and 45, respectively. 相似文献
11.
O'Dell et al. reported that rectal temperature was decreased by zinc deficiency in rats. However, it is not known whether
a combined deficiency of zinc and iron affects rectal temperature. Forty 4-wk-old male Sprague-Dawley rats were assigned into
four dietary treatment groups of 10 rats each for the 4-wk study: zinc-deficient group (4.5 mg Zn and 35 mg Fe/kg diet; −Zn),
iron-deficient group (30 mg Zn/kg diet, no supplemental iron; −Fe), zinc/iron-deficient group (4.5 mg Zn/kg diet, no supplemental
iron; −Zn−Fe), and control group (AIN-93G; Cont). At d 24–27, the rectal temperature was determined. The rectal temperature
of the −Zn group was significantly lower than the Cont group. The rectal temperature of the −Zn−Fe group was similar to that
of the Cont group, although thyroid-stimulating hormone and total thyroxin concentrations were the lowest in the −Zn−Fe group
among all groups. The pattern of the plasma nitrate/nitrite concentrations across groups was similar to rectal temperature.
Although observation of the rectal temperature is not conclusive, the balance between zinc and iron intake seems to determine
the body temperature set point. These results suggest that the thermogenic effect of thyroid hormones is not throught to influence
the paradoxical maintenance of rectal temperature in combined deficiency of zinc and iron. 相似文献
12.
Deficiency in the intake of trace elements, such as copper (Cu), iron (Fe), selenium (Se), and zinc (Zn), is very common in
the general population of most developing countries. A preliminary study in India and Pakistan showing the plasma levels of
Zn and Fe indicates that approx 50% of the subjects who participated have low levels of both Fe and Zn, suggesting a marginal
deficiency. The low plasma levels of these elements are more pronounced in females. The mean levels of Ze, Cu, and Fe in the
plasma of 83 subjects were 0.71 ± 0.11, 0.96 ± 0.10, and 0.80 ± 0.12 mg/L, respectively. The Cu:Zn ratio in the plasma was
1.43 ± 0.16. Three groups of 15 subjects each were given three different levels of oral supplements of Zn (15, 30, and 45
mg of Zn as Zn gluconate) for 6 wk, and blood samples were analyzed during various intervals. Plasma concentration of Zn increased
significantly (p < 0.001) in all the groups after 4 wk of supplementation and reached almost normal levels after 6 wk. Along
with the increase in Zn, there was a significant decrease(p < 0.001) in plasma Cu levels. There were no changes in the concentration of Fe during the supplementation period. The supplementation
was well tolerated by most subjects. The results of this pilot study indicate that Zn supplementation is a practical possibility
comparable to that of Fe supplementation in order to prevent marginal Zn deficiency in vulnerable groups in the general population
of developing countries. 相似文献
13.
Zinc (Zn) requirements are increased during lactation. Increased demand is partially met through increased Zn absorption from the diet. It is estimated that 60–80% of women of reproductive age are at risk for Zn deficiency due to low intake of bioavailable Zn and increased demands during pregnancy and lactation. How Zn is redistributed within the body to meet the demands of lactation, and how Zn deficiency affects this process, is not understood. Female C57bl/6J mice were fed a control (ZA; 30 mg Zn/kg) or a marginally Zn deficient (ZD; 15 mg Zn/kg) diet for 30 days prior to mating through mid-lactation and compared with nulliparous mice fed the same diets. While stomach and plasma Zn concentration increased during lactation in mice fed ZA, mice fed ZD had lower stomach Zn concentration and abrogated plasma Zn levels during lactation. Additionally, femur Zn decreased during lactation in mice fed ZA, while mice fed ZD did not experience this decrease. Furthermore, red blood cell, pancreas, muscle and mammary gland Zn concentration increased, and liver and adrenal gland Zn decreased during lactation, independent of diet, while kidney Zn concentration increased only in mice fed ZD. Finally, maternal Zn deficiency significantly increased the liver Zn concentration in offspring but decreased weight gain and survival. This study provides novel insight into how Zn is redistributed to meet the increased metabolic demands of lactation and how marginal Zn deficiency interferes with these homeostatic adjustments. 相似文献
14.
IntroductionZinc is an essential trace element having manifold functions within living cells. Zinc deficiency but also zinc excess impairs cell-specific functions whereas a balanced zinc level is required for an adequate cell behavior.Material and methodsThis study deals with the impact of cellular priming due to stimulation with interleukin (IL)-1, IL-2, IL-4, IL-6 or the chemokine CXCL12a and its subsequent influence on the intracellular free zinc concentration. Since cellular priming and activation is essential for proper immunological reactions, and across that highly cell-type specific, we investigated T cells, B cells, and peripheral blood mononuclear cells (PBMCs). Additionally, alterations of the intracellular zinc content was investigated by inducing zinc deficiency using the zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethane-1,2-diamine (TPEN) with subsequent re-supplementation of zinc, hence generating an intracellular zinc flux. Evaluation of zinc staining with FluoZin3-AM, Zinpyr-1 and Zinquin was done by flow cytometry or by fluorescence microscopy.ResultsOur results indicate that cellular priming for different periods of time (10 minutes/one hour) causes decreased intracellular free zinc concentrations in the FluoZin3-AM staining and increased zinc concentrations stained with Zinpyr-1. Furthermore, zinc supplementation after induced zinc deficiency leads to a fast and excessive rise of the intracellular free zinc levels in most cellular compartments.ConclusionOur study emphasizes the importance of zinc homeostasis and zinc distribution during cellular priming and for certain signaling cascades especially in T and B cells. Moreover, we demonstrated that zinc re-supplementation of zinc deficient cells results in significantly elevated intracellular free zinc concentrations compared to untreated controls. Hence, this underlines the need of a balanced zinc homeostasis for proper immune cell function. 相似文献
15.
Yan G. Zorbas Mitsui A. Sokiguchi Olav A. Johanson Youri F. Federenko 《Biological trace element research》1995,48(2):185-196
The objective of this study was to evaluate the effects of hypokinesia (HK) and fluid- and salt supplementation (FSS) on zinc
metabolism in endurance-trained volunteers (ETV) for a period of 364 d. Thirty long-distance runners aged 22–25 yr with a
peak VO2 of 67 mL/min/kg with an average 13.8 km/d running distance were chosen as subjects. They were equally divided into three
groups:
Throughout the duration of the study, groups 2. and 3. were maintained under an average running distance of 2.7 km/d, whereas
group 1. did not experience any modifications to their normal training routines and diets. Prior to and during the experimental
period, plasma volume, hemoglobin, sodium, potasium, hematocrit, osmolality, and protein concentrations were determined along
with the concentrations and urinary excretions of zinc, magnesium, calcium, and phosphorous. During the HK period, plasma
concentrations of these minerals increased significantly when compared to the HK+FSS and control groups. The same was observed
for the remaining parameters, which led us to conclude that during prolonged restriction of muscular activity, (PRMA) the
body of the HK+FSS volunteers acquire an apparent tendency to retain zinc, whereas in the HK group the opposite is observed. 相似文献
1. | Controls; |
2. | HK subjects; and |
3. | HK+FSS subjects. |
16.
The extracellular concentration of glutamate in the hippocampus is increased by hippocampal perfusion with CaEDTA, a membrane-impermeable zinc chelator, suggesting that the activity of glutamatergic neurons in the hippocampus are influenced by the extracellular concentrations of zinc. In the present study, the relationship between the extracellular concentrations of zinc and mossy fiber activity in the hippocampus was examined in mice and rats fed a zinc-deficient diet for 4 weeks. Timm's stain, by which histochemically reactive zinc in the presynaptic vesicles is detected, was attenuated in the hippocampus in zinc deficiency. The extracellular signal of ZnAF-2, a membrane-impermeable zinc indicator, was also lower in the hippocampal CA3, suggesting that the basal extracellular concentrations of zinc are lower maintained in zinc deficiency. To check mossy fiber activity after 4-week zinc deprivation, the decrease in the signal of FM4-64, an indicator of presynaptic activity (exocytosis), at mossy fiber synapses was measured under the condition of spontaneous depolarization. The decrease was significantly facilitated by zinc deficiency, suggesting that the basal exocytosis at mossy fiber synapses is enhanced by zinc deficiency. On the other hand, the increase in anxiety-like behavior was observed in the open-field test after 4-week zinc deprivation. The present study demonstrates that the decrease in the basal extracellular concentrations of zinc may be linked to the enhancement of the basal mossy fiber activity in zinc deficiency. This decrease seems to be also involved in neuropsychological behavior in zinc deficiency. 相似文献
17.
Zorbas YG Yaroshenko YY Andreyev VG Kuznetsov NK 《Physiological chemistry and physics and medical NMR》1998,30(2):219-228
The objective of this investigation was to measure the effect of prolonged restriction of motor activity (hypokinesia) of rats on the mass, density, mineral composition, reconstruction parameters and elemental composition of their bone tissue. The studies were done during 90 days of hypokinesia (HK) on 90 male Wistar rats equally divided into two groups: (1) vivarium control rats (VCR) and (2) hypokinetic rats (HKR). For the simulation of the hypokinetic effect the HKR group was kept for 90 days in small individual cages made of wood that restricted the movements of rats in all directions without hindering food and water intakes. During the prehypokinetic period of 15 days and during the hypokinetic period of 90 days bone mass, bone density, bone calcium and phosphorus concentrations, bone reconstruction parameters and elemental composition of bones were determined. During the same periods food intake and body weight losses were also measured. In the HKR group signs of osteoporosis in the spongy structures of the tubular bones were observed; they also showed significant decrease in rat femur weight, and in cross section of the rat femur, and in mineral concentrations of the femoral head when compared with the VCR group. The HKR group also show a significant decrease in food intake and body weight when compared with the VCR group. The corresponding parameters did not change significantly in the VCR group when compared with the baseline control values. It was concluded that prolonged exposure to HK induced osteoporosis and structural changes in bones. This apparently occurred due to inhibition of bone tissue formation in the HKR group. 相似文献
18.
Bucci I Napolitano G Giuliani C Lio S Minnucci A Di Giacomo F Calabrese G Sabatino G Palka G Monaco F 《Biological trace element research》1999,67(3):257-268
In subjects affected by trisomy 21 (Down syndrome), hypothyroidism is the most common endocrinological deficit. Plasma zinc
levels, which are commonly detected below the normal range in Down patients, are related to some endocrinological and immunological
functions; in fact, zinc deficiency has been shown to impair immune response and growth rate. Aims of this study were to evaluate
(1) the role of zinc deficiency in subclinical hypothyroidism and (2) thyroid function changes in Down children cyclically
supplemented with zinc sulfate. Inverse correlations have been observed between age and triiodotironine (T3) and between zinc
and thyroid-stimulating hormone (TSH); higher TSH levels have been found in hypozincemic patients at the beginning of the
study. After 6 mo of supplementation, an improvement of thyroid function (TSH levels: 3.96 ± 1.84 vs 2.64 ± 1.33 mUI/mL basally
and after 6 mo, respectively) was observed in hypozincemic patients. In the second cycle of supplementation, a similar trend
of TSH was observed. At the end of the study, TSH significantly decreased in treated hypozincemic subjects (4.48 ± 1.93 vs
2.96 ± 1.20 mUI/mL) and it was no longer different in comparison to normozincemic patients. We suggest zinc supplementation
to the diet in hypozincemic Down children as a simple and useful therapeutic tool. 相似文献
19.
The hematological effects of oral supplementation of zinc to training athletes are reported in the present study. A total
of 30 subjects between 16 and 22 yr of age volunteered to participate in a 4-wk study. They were equally divided into three
groups. Group 1 acted as resting controls receiving daily doses of 3 mg Zn/kg body wt. Group 2 was actively engaged in wrestling
and exercised for 90–120 min, 5 d a week. Group 3 was also actively engaged in wrestling and exercised for 90–120 min, 5 d
a week, but they were supplemented with 3 mg Zn/kg body wt per day. The erythrocyte, leukocyte, and thrombocyte counts and
the hemoglobin values of all subjects participating in the study were measured before and after exercise at the beginning
and at the end of the 4-wk study period.
In all groups, there were no significant differences in the measured parameters before and after exercise. At the end of the
supplementation period, the parameters of the subjects in groups 1 and 3 were significantly higher than those of group 2,
both before (p<0.005) and after (p<0.05) exercise. These results suggest that zinc supplementation has a positive effect on hematological parameters in athletes. 相似文献
20.
Yan G. Zorbas Youri F. Federenko Konstantin A. Naexu 《Biological trace element research》1995,50(1):57-78
The aim of this investigation was to evaluate the effect of a daily intake of fluid and salt supplementation on fluid and
electrolyte losses in endurance-trained volunteers during prolonged restriction of muscular activity (hypokinesia). The studies
were performed on 30 long-distance runners aged 23–26 who had a peak oxygen uptake of 65.5 mL/kg/min and had taken 13.8 km/d
on average prior to their participation in the study. The volunteers were divided into three groups: The volunteers in the
first group were placed under normal ambulatory conditions (control subjects), the second group of volunteers subjected to
hypokinesia alone (hypokinetic subjects), and the third group of volunteers was submitted to HK and consumed daily 0.1 g sodium
chloride (NaCl)/kg body wt and 26 mL water/kg body wt (hyperhydrated subjects). The second and third group of volunteers were
kept under an average of 2.7 km/d for 364 d. During the pre-experimental period of 60 d and during the experimental period
of 364 d sodium, potassium, calcium, and magnesium in urine and plasma were determined. Blood was also assayed for osmolality,
hemoglobin, hematocrit, plasma volume, plasma renin activity and plasma aldosterone. Mean arterial blood pressure was also
determined. In the hyperhydrated volunteers plasma volume and arterial blood pressure increased, whereas plasma osmolality,
plasma renin activity, plasma aldosterone, hematocrit, hemoglobin concentration, and urinary excretion and concentrations
of electrolytes in plasma decreased. In the hypokinetic volunteers, plasma volume and arterial blood pressure decreased significantly,
whereas hematocrit values, hemoglobin concenfration, plasma osmolality, plasma renin activity, plasma aldosterone, and electrolytes
in urine and plasma increased significantly during the experimental period. It was concluded that chronic hyperhydration may
be used in minimizing fluid and electrolyte losses in endurance-trained volunteers during prolonged restriction of muscular
activity. 相似文献