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Metal-Ligand Homeostasis in Epidermic Cells of Chernobyl Accident Liquidators


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The present article is an attempt to reveal the connection (Pearson) between potassium (K) and sodium (Na), K and zinc (Zn) levels on the basis of analytical determination of elemental content in human scalp hair (atomic emission spectrometry in 954 Chernobyl accident liquidators and 947 healthy persons). The negative K-Zn correlation and also the increase in epidermic cells K and Na and reduction of calcium (Ca) and Zn can indirectly point, in the authors opinion, to the participation of membrane АТРаs (P-type) in the origin of metal-ligand homeostasis shifts and serve as oxidative and nitrosative stress discriminators.
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Volume 1 • Issue 2 • 1000102
Vitam Trace Elem
ISSN: 2167-0390 VTE, an open access journal
Vitamins & Trace Elements
Petukhov et al., Vitam Trace Elem 2011, 1:2
Research Article Open Access
Metal-Ligand Homeostasis in Epidermic Cells of Chernobyl Accident
Petukhov VI1*, Dmitriev EV3, Kalvinsh I1, Baumane LKh1, Reste ED2, Zvagule T2, Skesters AP2 and Skalny AV4
1Latvian Institute of Organic Synthesis, Riga, Latvia
2Riga`s Stradin`s University, Riga, Latvia
3Institute of Numerical Mathematics, Russian Academy of Sciences, Moscow, Russia
4ANO “Centre of Biotic Medicine”, Moscow, Russia
The present article is an attempt to reveal the connection (Pearson) between potassium (K) and sodium (Na), K
and zinc (Zn) levels on the basis of analytical determination of elemental content in human scalp hair (atomic emission
spectrometry in 954 Chernobyl accident liquidators and 947 healthy persons). The negative K-Zn correlation and also
the increase in epidermic cells K and Na and reduction of calcium (Ca) and Zn can indirectly point, in the authors
opinion, to the participation of membrane АТРаs (P-type) in the origin of metal-ligand homeostasis shifts and serve as
oxidative and nitrosative stress discriminators.
*Corresponding author: Valery Petukhov, LV-1045, Riga, Latvia Eksporta st., 14-
14, Russia, Tel: 8-10 (371)6 7381393; E-mail:
Received December 05, 2011; Accepted January 30, 2012; Published February
06, 2012
Citation: Petukhov VI, Dmitriev EV, Kalvinsh I, Baumane LKh, Reste ED, et al.
(2011) Metal-Ligand Homeostasis in Epidermic Cells of Chernobyl Accident
Liquidators. Vitam Trace Elem 1:102. doi:10.4172/2167-0390.1000102
Copyright: © 2011 Petukhov VI, et al. This is an open-access article distributed
under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the
original author and source are credited.
Analysis of dynamic characteristics of metal-ligand homeostasis
(MLH) in dierent biosubstrates is an intriguing, virtually not studied
question of modern elementology. Such analysis, of course, cannot
be conned (though this information itself is undoubtedly valuable)
to only quantitative estimation of the content of one or another metal
in a biosubstrate. Data on the metal-ligand complexes themselves,
rst on metalloproteins, which are the main participants of intra- and
extracellular MLH events, are not less actual.
It is known that existence of metals in the organism in “free” form
(as ions) is virtually “forbidden” even for such essential metals as copper
(Cu), zinc (Zn), magnesium (Mg) etc., to say nothing of cadmium (Cd)
and mercury (Hg), which are yet considered in literature as “toxic” [1].
As it was shown in recent experiments on a model of yeast cells, copper
concentration in their plasma was less than 10-18 M, i.e. less than one
copper atom per cell [2].
At the same time, there are apparently no dierence in principle
between toxic eect of Zn2+ or Cu2+ on a cell and that of Cd2+ or
Hg2+. Most probably, the matter is some faults in binding metals by
specialized protein molecules (metallothioneins, metallochaperones)
and/or ineective removal of these ions from cells by assistance of
membrane ATPases.
e major role in binding (detoxication) of metals in the
organism belongs to metallothioneins (MT), low-molecular proteins
(6-7 kDa), where 20 of 60-68 amino-acid residues are cysteine. Since
1957, when a Cd, Zn-containing MT was found rst [3], new data on
MT participation in MLH appeared.
It was found that MT besides detoxication of heavy metals and/
or metals with variable valence (Fe, Cu) protect cell structures from
damaging eect of oxygen/nitrogen radicals [4,5], inuence activity of
nuclear transcription factor NF-kB, participate in regeneration of liver
and nervous cells [6,7], cause corrigent inuence on humoral and cell
immunity [8,9].
In cells, MT synthesis is induced (besides metals themselves and
oxygen/nitrogen radicals) by glucocorticoids, anti-inammatory
cytokines (TNFα, IL-1), α-interferon [10-13].
ere are four MT classes. Two of them, MT-1 and MT-2, are
expressed in almost all mammalian tissues. ey play a key role
in homeostasis of Zn2+, Cu2+, Cd2+ and Hg2+. e other two, MT-3
and MT-4, are tissue-specic for neural (CNS) and epithelial tissue,
respectively [14]. Zn2+ ions incorporate MT molecule relatively easy
and are claimed to be equally easy displaced by excess Cd2+ under
certain conditions.
e metal/thiols ratio in MT is not random. ere is about 1 Cu
atom per 2 cysteine residues in Cu-containing MT (Cu-MT), and 1
atom of Cd or Zn per 3 cysteine residues in Cd/Zn-containing MT
(Cd/Zn-MT). In Cu-MT, each copper atom is trigonally surrounded
by sulphur (S) atoms, while the corresponding complex in Cd/Zn-MT
has tetrahedral structure.
Structural regularity of the metalloprotein (MP) molecules allows
existence of linear bounds between metals included in MP. ese bonds
can serve like “markers” of MP, and can be detected by correlation
analysis (Pearson) of metal concentrations in a certain biosubstrate.
We guess that such approach could be ecient for studying dynamic
changes of MLH in normal and various pathological states. Using
this method, one could trace MLH changes in such a biosubstrate as
epidermis under conditions of oxidative and nitrosative stress, e.g.
in Chernobyl disaster liquidators. Moreover, the subject for direct
determination of metal concentrations could be not the epidermal
cells themselves, but their derivatives (hair). ough, in this case, we
should assume that metal concentrations in cells correspond to those
in hair. is assumption looks reasonable and can be veried in further
observations. Advantages of hair use for non-invasive and retrospective
observation on shis in MLH of epidermal cells are obvious and would
be especially appropriate for mass (population) investigations.
e deepness of retrospection in such observations can be easily
estimated on the basis of average speed of human hair growth ca. 0.2
mm/day: a sample of hair ca. 3 cm long reects events, happened in
epidermis during ve recent months.
At the same time, the choice of biosubstrate for elemental analysis
(hair) requires carefulness when interpreting the investigation results.
Citation: Petukhov VI, Dmitriev EV, Kalvinsh I, Baumane LKh, Reste ED, et al. (2011) Metal-Ligand Homeostasis in Epidermic Cells of Chernobyl
Accident Liquidators. Vitam Trace Elem 1:102. doi:10.4172/2167-0390.1000102
Page 2 of 8
Volume 1 • Issue 2 • 1000102
Vitam Trace Elem
ISSN: 2167-0390 VTE, an open access journal
It is known that epithelium (with its derivatives), which takes
part in assimilation of chemical elements and their removal from the
organism, is an area, where regulatory mechanisms of MLH cannot
help manifesting themselves. erefore an increase in relative amount
of metals (or other chemical elements) in hair, if not being due to
external causes, can be explained by:
1) normal working of MLH regulatory system (e.g. accelerated
excretion of a metal in response of its excess intake from food);
2) a fault of regulatory mechanisms promoting metal retention
in the organism, that leads to development of metal-decient
In its turn, at insucient intake of one or another metal from
outside (or from chelate complexes inside the organism), proper
work of the homeostasis regulatory system is directed to retention of
the metal inside (minimization of losses), that can be manifested in a
decrease of relative amount of the metal in such biosubstrate as hair.
Among oscillations in concentration of chemical elements (in a
rather wide range) registered in spectrometric analysis of hair, how
to distinguish those inherent in normal homeostatic regulation from
pathological shis, signs of elemental imbalance? Where are distinctive
criterions of these shis?
ese questions are yet to be answered. However already today
one should admit that it is hardly reasonable to extrapolate data of
hair analysis upon whole organism, i.e. to diagnose “total” elemental
imbalance on the basis of just quantitative determination of hair
mineral content (“more - less”).
Such extrapolation is probably applicable only in case of distinct
(general) deciency or excess of certain elements, when rough
disturbances of mineral content can be found in most tissues.
at is why a signicant advance (in theoretical and especially
practical sense) would be the very possibility to use results of hair
spectrometry for retrospective estimation of MLH events in epidermal
cells. In other words, in case of quite predictable identity of mineral
content of epidermis and its derivatives (hair), the latter could be a
reliable and aordable source of information about mineral status of
epidermal cells.
In this work we made an attempt to reveal pair associations between
concentration of sodium (Na) and potassium (K), as well as between
K and Zn as an indirect conrmation of participation of membrane
ATPases (P-type) in MLH changes, observed on the background of
oxidative and nitrosative stress.
For this purpose we used data on atomic-emission spectrometry of
hair from Chernobyl disaster liquidators and healthy persons.
Materials and Methods
Hair mineral content of 947 healthy persons, 2-86 years old (238
men, 709 women) and 954 Chernobyl accident liquidators, 37-82 years
old, living in Moscow, Russia (741 men, 213 women), was analysed by
atomic emission spectrometry with inductively coupled plasma (ICP-
AES) on an Optima 2000 DV (Perkin Elmer Inc., USA) instrument in
ANO “Centre for Biotic Medicine” (Moscow, Russia).
In addition, in order to reveal possible gender and age dependent
dierences, hair mineral content of 402 healthy residents of Riga,
Latvia, 2-86 years old (322 women, 80 men) was also investigated by
ICP-AES. All the persons were divided in 3 groups by age: Group 1
– 2-32 years old (n=154), Group 2 33-44 years old (n=127), Group
3 – 45-86 years old (n=121). Comparative analysis of the spectrometry
data was made for dierent genders and for two opposite age groups:
Group 1 and Group 3.
e hypothesis of normal data distribution was tested using
Jarque-Bera [15] and Kolmogorov-Smirnov [16] tests. In statistical
calculations of the spectrometry data we did not use ordinary
statistical methods (t-test), because the normality testing disproved
the hypothesis of normal data distribution with high probability for
all chemical elements except zinc (Zn) [17]. erefore, alternative
approaches (bootstrap method) were applied, which do not require
normal distribution of a priori data [18]. Correlation analysis was
made using standard computer application packages Microso Excel
and Matlab.
Comparative analysis of gender and age dependent dierences in
mineral hair content of healthy persons has given the results presented
in (Tables 1,2).
Interval estimation of average hair content of such elements as
calcium (Ca), magnesium (Mg), manganese (Mn), phosphorus (P),
tin (Sn) was considerably dierent in healthy men comparing to
women. Mean values (M, µg/g) and limits of the condential intervals
(bootstrapping) for men are: Ca=749.1 [521.1-1125.4]; Mg=73.4 [59.9-
89.6]; Mn=0.73[0.55-0.97]; P=154.3 [146.3-161.8]; Sn=0.18[0.14-
0.21]; V=0.12[0.09-0.15]; for women: Ca=1537.5[1410.9-1666.4];
Mg=188.9 [169.6-209.1]; Mn=1.61 [1.33-1.96]; P=139.2 [134.7-143.9];
Sn=0.85[0.52-1.34]; V=0.07 [0.06-0.08]. Age dependent dierences
between two marginal age groups (Group 1 and Group 3) were found
only for Mg: in Group 1 Mg=141.9 [120.9-166.1] µg/g; in Group 3 Mg
=203.4 [168.9-243.4] µg/g.
e results indicate necessity of being careful, as mentioned above,
when generalizing estimation of mineral status by hair spectrometry on
the whole organism. For instance, the fact of higher Ca content in hair
of women comparing to men do not testify good state of Ca homeostasis
in women’s bone tissue, where 99% of this mineral is situated.
Comparative analysis of mean concentrations of 23 chemical
elements in hair of healthy persons and Chernobyl disaster liquidators
was made using interval estimation of the mean [18]. e results are
presented in (Table 3).
Sex Ca (μg/g)
Mg (μg/g)
Mn (μg/g)
P (μg/g)
Sn (μg/g)
V (μg/g)
(n=80) 521,1<749,1<1125,4 59,9<73,4<89,6 0,55<0,73<0,97 146,3<154,3<161,8 0,14<0,18<0,21 0,09<0,12<0,15
(n=322) 1410,9<1537,5<1666,4 169,6<188,9<209,1 1,33<1,61<1,96 134,7<139,2<143,9 0,52<0,85<1,34 0,06<0,07<0,08
Note: hereinafter in the tables the bold font designates values of average (M), usual - borders of condential intervals (bootstrap-method).
Table 1: Sex dependent differences in hair mineral content of healthy persons.
Citation: Petukhov VI, Dmitriev EV, Kalvinsh I, Baumane LKh, Reste ED, et al. (2011) Metal-Ligand Homeostasis in Epidermic Cells of Chernobyl
Accident Liquidators. Vitam Trace Elem 1:102. doi:10.4172/2167-0390.1000102
Page 3 of 8
Volume 1 • Issue 2 • 1000102
Vitam Trace Elem
ISSN: 2167-0390 VTE, an open access journal
As follows from (Table 3), content of virtually all investigated
elements in hair of Chernobyl disaster liquidators signicantly diers
from control. It is notable that content of essential metals (Cu, Zn, Mg
etc.) in hair of liquidators is lower than in control group, but content
of so-called “toxic” metals (Cd, Pb, Sn) is higher. What is behind these
shis? Could one consider them as distinct faults of metal-ligand
homeostasis, or they are just a peculiar compensatory response of the
organism under conditions of oxidative/nitrosative stress, aimed at
saving vital elements inside and removing less important or potentially
toxic ones?
To try answering these questions, we have postulated the following
issues, based on published data and our own observations.
1. e main distinctive feature of biochemical processes in
Chernobyl liquidators is high activity of oxygen/nitrogen
radicals, or chronic oxidative/nitrosative stress, which directly
concerns events of metal-ligand homeostasis observed inside
and/or outside cells.
2. Key role in metal-ligand homeostasis belongs to metal-proteins
(MT, chaperons, metal-enzymes).
3. If assume that ratio of metals (and, consequently, their protein
ligands too) in hair is equal to that in epidermal cells (and
this assumption can be conrmed by further investigations),
therefore a real possibility appears to judge about events of
metal-ligand homeostasis in epidermis on the basis of changes
in mineral content of hair.
4. Linear correlations in pairs “metal-metal” or “metal-protein”
can serve as additional characteristics of their intracellular
interactions and/or as an indirect evidence of structural bonds
between metals (e.g. in MT molecule).
Some technical peculiarities of detection of the linear associations
between metals in hair spectrometry results should be explained [19].
It was established that a reduction of the subgroup size (to n = 100)
caused a multiple increase in the number of detected linear associations
as compared with the whole group (n = 1000). It points to the fact that
most of these correlations are casual and dependent on the subgroup
size. is circumstance determines the following rules of the correlation
analysis procedure.
To reveal the maximum number of signicant correlations, entire
assemblies of spectrometry data (in our observations n=947 and n=954)
was subjected to repeated “shue” (“shaking”). e “shue” was made
in accordance with specially designed formats (standards). For this
purpose, in the entire assembly we found the ratio of concentrations
in each possible pair of chemical elements for each observation. It
was essential that the sum of numerators was more than the sum of
denominators in each set of ratios for a given pair.
e set of such pairs, as determined by number of possible paired
combinations of m (where m is the number of analysed minerals), is a
set of formats for the ‘shue’ of the entire assembly. If m = 23 (as in this
case), the number of formats is 253.
In the present study we used the following 20 formats only: Mg/Pb,
Al/As, Cu/As, As/Cd, K/As, Zn/Li, Ca/Al, K/Mg, Fe/Cu, Fe/Cd, Si/Cr,
Cr/Co, Si/Ni, Si/Se, Na/Mn, P/Ni, Si/Co, P/Si, Na/Se, Ni/Cr.
In each obtained format, the ‘ranking’ (or ‘formatting’) of
individual data was performed according to value of elements ratio in
the given pair in descending order (from high to low). e optimum
size of sample for studying correlations is approx. 100 persons. In the
same order (from high to low) groups for the correlation analysis were
designed. For example, if the entire assembly is ca.1000 persons, than
Group 1 includes #1-#100, Group 2 - #101-#200, Group 3 - #201-#300,
e correlations between chemical elements, on which the shue
was formatted (and only within the given particular format), were not
allowed for, because, by experience, this method of formatting leads to
articial overstating of Pearson correlation coecient (r).
Aer calculating r in all groups and both entire assemblies (healthy
persons and disaster liquidators), a new combined assembly was
created involving only groups with r>0.2. Within this new assembly,
formed for a given pair, the spectrometry results were selected further
depending on r values.
For this purpose, for each case a so-called ‘occurrence coecient’
(OC) was found, which was equal to the number of repetitions of a
given observation in the entire assembly. At no repetitions OC=0, one
repetition corresponds to OC=1, two repetitions - OC=2 etc. For the
investigated relations, the near-to-zero r values were found among
those cases, where repetitions were absent (OC=0) or rarest. At the
same time, the maximum number of repetitions was accompanied by
maximum r values. Such an approach allowed relatively easy separation
of persons with absence or presence of a sought-for linear association
Age groups Mg [M] мкг/г
Group 1 (n=154)
men – 32 (20,8%);
women – 122 (79,2%)
Group 3 (n=121)
men – 26 (21,5%);
women – 95 (78,5%)
Table 2: Age dependent differences in hair mineral content of healthy persons.
Healthy persons (n=947)
M (μg/g)
Chernobyl disaster liquidators (n=954)
M (μg/g)
Note: *– signicant difference
Table 3: Interval estimation of mean content of chemical elements in hair of
Chernobyl disaster liquidators and healthy persons.
Citation: Petukhov VI, Dmitriev EV, Kalvinsh I, Baumane LKh, Reste ED, et al. (2011) Metal-Ligand Homeostasis in Epidermic Cells of Chernobyl
Accident Liquidators. Vitam Trace Elem 1:102. doi:10.4172/2167-0390.1000102
Page 4 of 8
Volume 1 • Issue 2 • 1000102
Vitam Trace Elem
ISSN: 2167-0390 VTE, an open access journal
e obtained results have not just conrmed the existence of the
K-Zn correlation but also revealed the dierences in its manifestation
in the compared groups. us, the negative linear correlation between
K and Zn (r = -0.43; p<0.05) was only manifest in 18.1% of practically
healthy persons; in 36.3% it was negligible (r = -0.23; p<0.05), and in
45.6% it was altogether absent (r = 0.05).
Whereas the K-Zn correlation was negative and signicant (r -
from -0.41 to -0.62; p<0.05) in the absolute majority of the Chernobyl
disaster liquidators (88%), and in 12% of the liquidators it was not
revealed at all (r = - 0.03). Besides, the K-Zn correlation at the highest
|r| (in both the liquidators and the healthy subjects) was accompanied
by a signicantly higher level of K and Na and lower level of Zn than in
subjects showing no K-Zn correlation (See Table 4).
It is indicative that the |r| size at K-Zn correlation varies with the
increase of OC (Table 5,6), just like the average concentration values of
not only K, Na and Zn but some other metals as well.
e negative correlation between K and Zn means that a decrease of
intracellular zinc concentration must result in a proportional increase
of intracellular potassium concentration. is fact should be discussed
at greater length. Here, however, we can only conne ourselves to
assuming that the most probable cause of such relations between K and
Zn is an increase in production of nitric oxide (NO), which selectively
releases Zn from MT molecules. Besides, NO (or its derivatives and
between concentrations of chemical elements among the whole totality
of cases.
Alongside with the measurements of pair correlations between
metals, we were interested in the associations between the concentrations
of these metals in hair and the r values. Of special interest were possible
deviations of the results obtained in the Chernobyl disaster liquidators
from the norm. Such deviations could claim to be the distinctive
markers of the chronic oxidative/nitrosative stress provided that the
destructive action of oxygen/nitrogen reactive species extends to
metal-ligand homeostasis of epidermal cells.
When performing the correlation analysis, we were rst interested
in associations between concentrations of Zn, K and Na. It should
be noted that Zn is a part of MT molecule while a linear correlation
between K and Na concentrations in hair, according to our preliminary
data [19], is very constant, characterized by relatively high r values (0.6-
0.7), and does not depend on the sample size. At the same time, the
K-Na association depends on the biosubstrate type: it is present in hair
and absent in plasma. It suggests that this correlation reects, directly
or indirectly, the ne-tuned operation of membrane Na,K-ATPases,
which are constantly present in the cell and ensure the transmembrane
transport of metals.
It was interesting to nd out whether there were any correlations
between K and Zn and what kind of correlations could be observed in
the Chernobyl disaster liquidators and healthy persons.
Correlation (r)
and incidence of K-Zn
at the given r
Potassium (K)
Sodium (Na)
Zinc (Zn)
r = - 0,05 [45,6%]
(n=432) 92,2<125,3<165,8 183,8 <209 <243,2 194,3<200,1<205,7
r = - 0,43 [18,1%]
(p<0,05) (n=171) 729,0<894<1084,5 996,2<1233,9<1474,1 143,5<150,7<158,1
r = - 0,03 [12,0%]
(n=115) 102,5<150,5<208,3 199,4 <261,8< 328,0 172,3<183,5<194,5
r = - 0,62 [21,5%]
(p<0,05) (n=205) 502,9<578,1<660,5 982,7<1131,3 <1286,4 153,5<159,3<165,4
Note: The Table gives the extreme (max and min) r values only
Table 4: K-Zn correlation and K, Zn content in hair of Chernobyl disaster liquidators and healthy persons.
Number OC n r
1-253 4-10 253 -0,01 21,0 127,0 197,8 204,3 915,3 1737,9 93,9 171,0
254-432 11 179 -0,17 23,1 122,9 224,8 194,2 938,5 1463,8 92,3 151,6
433-619 12 187 -0,20 21,5 210,8 356,8 189,4 719,5 1287,0 76,3 141,1
620-776 13 157 -0,24 21,5 346,8 557,0 176,8 900,2 1234,8 107,0 145,1
777-872 14 96 -0,31 16,8 522,9 943,2 164,0 1040,1 970,8 116,0 109,9
873-947 15-17 75 -0,44 15,0 1368,9 1605,9 133,6 637,0 915,2 72,9 138,6
Note: Caм and Mgм - Ca and Mg concentrations in men’s hair; Caf and Mgf - in women’s hair
Table 5: K-Zn correlation and concentration of metals in epidermic cells of healthy subjects depending on occurrence coefcient (OC).
Number OC n r
1-115 6-11 115 -0,03 10,9 150,5 261,8 183,5 706,5 1418,8 47,1 119,6
116-229 12 154 -0,31 10,8 224,9 477,2 177,4 592,9 1081,7 38,2 89,1
270-503 13 234 -0,43 11,2 394,9 833,2 158,6 595,5 910,5 40,3 64,6
504-749 14 246 -0,43 10,9 464,8 1036,3 162,4 531,2 710,8 35,5 55,9
750-954 15-17 205 -0,62 11,0 578,1 1131,3 159,3 537,7 611,3 40,5 44,6
Note: Ca
and Mg
- Ca and Mg concentrations in men’s hair; Ca
and Mg
- in women’s hair
Table 6: K-Zn correlation and concentration of metals in the epidermic cells of Chernobyl disaster liquidators depending on occurrence coefcient (OC).
Citation: Petukhov VI, Dmitriev EV, Kalvinsh I, Baumane LKh, Reste ED, et al. (2011) Metal-Ligand Homeostasis in Epidermic Cells of Chernobyl
Accident Liquidators. Vitam Trace Elem 1:102. doi:10.4172/2167-0390.1000102
Page 5 of 8
Volume 1 • Issue 2 • 1000102
Vitam Trace Elem
ISSN: 2167-0390 VTE, an open access journal
rst of all peroxynitrite) apparently initiates transmembrane metal
transport processes (Zn – from the cell, K – into the cell), where an
active role is played by transport proteins (metallochaperones) and
membrane ATPases [20].
Assuming that the linear association between Na and K is due to the
coordinated work of membrane ATPases, there emerges a reasonable
interest in comparative analysis of K–Zn correlation in Chernobyl
disaster liquidators and healthy subjects because both Na,K-ATPase
and the membrane pump for Zn belong to the same type (P-type) of
ATPases, although they represent dierent subgroups of those.
In our view, the negative nature of association between Na and K
concentrations in both assemblies (in the presence of K-Zn association)
can testify an increase in activity of P-type ATPases regarding
dierently-directed transmembrane transport of K+ and Zn2+ under the
conditions of oxidative/nitrosative stress.
In this connection, it would be appropriate to refer to the results
of the redox status research in Chernobyl disaster liquidators received
earlier [21] (See Table 7).
As Table 6 shows, the analysis of the redox status of Chernobyl
disaster liquidators evidences an appreciable and stretched in time
prooxidant shi (chronic oxidative stress) which cannot be liquidated
completely even aer antioxidant therapy.
At the same time, accepting the assumption that the negative K-Zn
association can indirectly point to an increased intracellular production
of oxygen and nitrogen radicals, one must explain the fact that a part
of healthy subjects (18.1%, see Table 4) in this respect varies little from
disaster liquidators. It is also unclear why in both investigated groups,
regardless of gender (Table 5 and 6), the Ca concentration in epidermic
cells falls while |rK-Zn| increases?
e close relation between NO and intracellular calcium
homeostasis is well known: via activation of soluble guanylyl cyclase
(sGC), cyclic guanosine monophosphate (cGMP), cGMP-dependent
protein kinase (PKG-I) and Ca2+ATPase [22]. One of the nal eects of
NO-dependent induction of this signalling path (at least for muscular
cells) is increased excretion of Ca from the cell.
Our comparative analysis of Ca concentration values in people
with and without detected negative K-Zn correlation separately for
men and women (let us remind that hair Ca content according to our
data was dependent on gender) gave the following results.
Regardless of gender, in groups with rK-Zn= -0,43 (healthy persons)
and rK-Zn= -0.62 (disaster liquidators) the hair Ca content was
signicantly lower than in the group with rK-Zn= -0.05 (healthy persons)
and rK-Zn= -0.03(disaster liquidators).
us, in healthy men, the mean Ca content in the group with rK-
Zn = -0.05 was 934.7 [745-1137.5] µg/g, while in the group with rK-Zn
= -0.43 it was just 856.9 [633.9-1107.1] (in square brackets – interval
estimation of the mean by the bootstrap method). In healthy women
with rK-Zn = -0.05 this parameter was equal to 1627.8 [1486.8-1776.5]
µg/g while in those with rK-Zn = -0.43 – just to 946.8 [787.1-1128.5] µg/g.
In the group of Chernobyl disaster liquidators with coecient rK-Zn =
-0.03, equal for men and women, the Ca level in men was 706.5 [622.9-
803.4] µg/g, in women – 1418.8 [1059.5-1815.8] µg/g. while in those
with rK-Zn = -0.62 this parameter in male liquidators was equal to 537,7
[506,1-570,4] μg/g; in female liquidators it was 611,3 [508,1-793,3] μg/g
(See Table 8).
e obtained results agree with our suggestion that the negative
association between K and Zn together with signicant decrease of Ca
level can indicate activation of intracellular radical reactions with NO
One can try to reveal interrelation between Ca, K and Zn
concentrations without correlation analysis. For this, in both entire
assemblies (separately for men and women) one needs to compare
mean levels of K, Zn at patently low level of Ca (lower than the lower
limit of interval bootstrap estimation of the mean) with mean K,
Zn in the rest of persons within the subsample. e results of such
comparison are shown in (Tables 9,10).
As (Tables 9,10) show, the low Ca level (groups I) was accompanied
by increased K concentration and decreased Zn concentration (as
compared with Groups II), with condence being proved by interval
estimation of the mean (bootstrapping) in most cases.
Analyses/Units Years 1998 – 1999 Year 2007
Lipid peroxides and hydroperoxides [LOO. , LOOH] (conv.units) 210,0 ± 30,7 [normal value < 80 ] 121,7 ± 10,84 [normal value < 80 ]
Blood plasma oxydizability (conv. units) 450, 0 ± 44,8 [normal value < 200] 440,6 ±51,82 [normal value < 200]
Lipid peroxidation processes ratio (conv. units) 9, 94 ± 1,01 [normal value < 4,0 ] 6,67 ± 0,71 [normal value < 4,0 ]
Selenium content in blood plasma (µg/L) 56,1 ± 3,3 (min.17,0 µg/L) [normal value. 80
- 120]
79,8 ± 3,94 (min.43,0µg/L) [normal value 80
- 120]
Glutathione Peroxidase in blood plasma (IU/L) 380,0 ± 19,4 [normal value 450 - 600] 398,0 ± 21,[normal value 450 - 600]
Glutathione Peroxidase in blood (IU/gHb) 26,1 ± 1,98 [normal value 35 - 50] 38,25 ± 1,84 [normal value 35 - 50]
Table 7: Redox status of Chernobyl disaster liquidators.
Groups Correlation
( r )
Ca (μg/g)
men women
r = - 0,05
(n = 432)
745,0 <934,7< 1137,5
r = - 0,43 (p<0,05)
(n = 171)
639,9< 856,9< 1107,1
787,1 <946,8<1128,5
r = - 0,03
(n = 115)
622,9 <706,5 < 803,4
r = - 0,62 (p<0,05)
(n = 205)
506,1<537,7< 570,4
508,1<611,3< 739,3
Note: The Table gives the extreme (max and min) r values only
Table 8: K-Zn correlation and Ca concentration in epidermic cells.
Citation: Petukhov VI, Dmitriev EV, Kalvinsh I, Baumane LKh, Reste ED, et al. (2011) Metal-Ligand Homeostasis in Epidermic Cells of Chernobyl
Accident Liquidators. Vitam Trace Elem 1:102. doi:10.4172/2167-0390.1000102
Page 6 of 8
Volume 1 • Issue 2 • 1000102
Vitam Trace Elem
ISSN: 2167-0390 VTE, an open access journal
Undoubtedly, any conclusions that could be drawn on the basis
of this investigation are largely provisional. However, the long-felt
requirement in additional (apart from quantitative analysis) information
about the events really happening with metal-ligand complexes seems
inarguable. ese events, named metal-ligand homeostasis, are unlikely
to be correctly interpreted without understanding the role of ligands
in realization of the known biological eects which are traditionally
attributed to metals only.
Analysis of linear correlations between chemical elements (on the
basis of spectrometry results) is to help in getting such information
about MT, which are the most prevalent protein ligands for cadmium,
copper and zinc. In this connection it seems expedient (together with
determination of metals) to make quantitative estimation of MT or
their apoforms, thioneins, in one or another biosubstrate (which can
be the subject of further investigations).
It was found that a MT molecule includes two domains, α and β,
which have considerable, dierences [23]. One of these dierences
is unequal terminal amino acid residues in metal-binding clusters.
In the α domain, designed mostly for ‘toxic’ metals (particularly for
Cd), the terminal residues are carboxyls (carboxyl-terminal domain),
in the β domain – amino groups (amino-terminal domain). is β
domain chiey binds essential metals (Zn, Cu), and it is the one from
which nitroxide selectively releases Zn2+ through nitrosylation of thiols
(formation of S-nitrosothiols), leaving Cd-containing α domain intact
Other examples of functional interrelation between MT and NO
are also known. It was found that they have some common transmitters
(TNFα, IL-1, lipopolysaccharides) for induction of their intracellular
synthesis, and the MT molecule can serve as a trap for aggressive
nitrogen radicals. In addition, according to some researchers, Zn2+
released from MT can inhibit inducible NO-synthase (iNOS) and thus
prevent NO hyperproduction in cells [24].
Zn2+ release largely depends on the redox status of the cell where
prooxidant shis (e.g. accumulation of oxidized glutathione – GSSG)
facilitate Zn2+ release from MT molecules while reduced glutathione
(GSH) without presence of GSSG inhibits this process [25,26]. us,
Zn bond with β domain becomes unstable under conditions of both
oxidative and nitrosative stress [27,28].
is circumstance directly concerns Chernobyl disaster liquidators,
whose redox status was found [21] to demonstrate distinct prooxidant
shis: 3-5 fold increase of plasma chemiluminescence above norm, a
signicant decrease in activity of erythrocytic Se-dependent glutathione
peroxidase (GSH-Px-I).
Nitrosylation of thiols by nitroxide in β domains can release not
only Zn2+ but also Cu2+ from Cu-containing MT (Cu-MT). In this
case, if Cu2+ binds to apoform of Cu,Zn-superoxide-dismutase (apo-
ZnSOD), then Cu-MT can play the role of metallochaperone for one of
the key antioxidant enzymes in the cell [29].
Aer breaking from bonds of MT by means of nitrogen or oxygen
radicals, essential metals (Zn, Cu) have a choice: either to remain in
the epidermal cell in order to help it overcome oxidative/nitrosative
stress (e.g. as a part of antioxidant enzymes and/or as a suppressor
of NO hyperproduction), or to leave the cell. e latter choice looks
apparently less benecial for epidermis and its derivatives. However,
this is the choice which allows the organism to save essential metals,
whose necessity obviously rises at activation of radical processes.
An absolutely dierent situation exists for ‘toxic’ metals,
particularly Cd, in epidermis and its derivatives. Being eciently
secured from the release-eect of nitrogen/oxygen radicals in MT’s α
domain, these metals not only can remain in the cell but, according to
our observations (See Table 3), can also accumulate in the epidermal
derivative (hair). What does such accumulation mean for the whole
It means that all the body surface (in a man – ca.2m2), almost
completely covered by hair (except for palms and soles), becomes
the area where the organism removes excess of heavy and/or ‘toxic’
metals by pushing them into permanently desquamating epidermis
and growing hair. Such a reaction seems ecient and evolutionary
reasoned, and it can be surely claimed a compensatory/adaptive one
not only against heavy metal poisonings, but also in case of chronic
disturbances of the organism’s redox status – prooxidant shi, which
happens in Chernobyl disaster liquidators.
is idea is further conrmed by the data on the signicant
increase of Zn, Cu level in blood of disaster liquidators as compared
to norm [21]. It is notable that the considerable increase of Cu
concentration in blood of liquidators was accompanied by normal
level of ceruloplasmin. Unfortunately, the aforesaid authors did not
determine the MT concentration in plasma; therefore, it is dicult to
interpret the data.
Healthy subjects (n=947)
Women (n=709) Men (n=238)
Group I (n=437) Group II (n=272) Group I (n=149) Group II (n=89)
Ca (μg/g) 675.7<707.5<739 2494.6<2615.7<2746.6 318.5<335.4<351.3 888.1<1096.5<1408.2
K (μg/g) 268.6<336.3<412.6 171.6<226.2<293.2 290.5<380.2<475.2 191.1<324.7<494.7
Zn (μg/g) 171.3<176.2<181.1 196.4<205.6<215.1 154.5<162<168.8 190.2<205.3<220.3
Table 9: Comparative analysis of hair K, Zn content in groups of healthy subjects with different Ca level.
Chernobyl disaster liquidators (n=954)
Women (n=213) Men (n=741)
Group I (n=134) Group II (n=79) Group I (n=453) Group II (n=288)
Ca (μg/g) 477.6<505<739 1457.6<1634.7<1852.2 394.8<403.1<411.9 814.7<851.9<893.3
K (μg/g) 285.6<357.2<439.3 159.9<216<281 424<468.8<512.6 291.9<346.3<404.1
Zn (μg/g) 156.7<164.2<171.6 170.9<183.5<197.8 148.7<152.6<156.8 176.3<182.6<189.4
Note to Tables 9, 10: Group I – persons whose individual Ca levels do not exceed the lower limit of interval bootstrap estimation of the mean; Group II – the rest of the
given subsample. Bold font – mean values, regular font – limits of condence intervals
Table 10: Comparative analysis of hair K, Zn content in groups of Chernobyl disaster liquidators with different Ca level
Citation: Petukhov VI, Dmitriev EV, Kalvinsh I, Baumane LKh, Reste ED, et al. (2011) Metal-Ligand Homeostasis in Epidermic Cells of Chernobyl
Accident Liquidators. Vitam Trace Elem 1:102. doi:10.4172/2167-0390.1000102
Page 7 of 8
Volume 1 • Issue 2 • 1000102
Vitam Trace Elem
ISSN: 2167-0390 VTE, an open access journal
Particular mechanisms of metal transfer through cell membrane
are insuciently studied. A key role in this process belongs to rather
large set of ATPases, which consists of ve subsets (I, II, III, IV and
V). e P-type of these enzymes (rstly PIb and PII) is most interesting
for us because the P-type ATPases provide transmembrane transport
of such ions as H+, Na+, K+, Cu+, Zn2+, Ca2+, Mg2+, Cd2+ etc [30,31].
Energy necessary for such transport, which runs against concentration
gradient, comes from ATP hydrolysis. It is assumed that nitrosylation
of S-containing proteins in the structure of KATP channels under
conditions of nitrosative stress leads to activation of these channels
It seems no mere chance to us that the existence of interrelation
between K+ and Zn2+ ion counter-ows (which can be seen in the
detected negative correlation K - Zn in Chernobyl liquidators and
partly in healthy subjects) is accompanied by a signicant decrease
of Ca concentration in epidermal cells. In our opinion, such a
combination (being a kind of discriminator) can point to activation of
redox processes involving nitrogen/oxygen radicals in epidermis.
Unfortunately, the authors had no data about the doses of
radioactive elements (J131, Cs137, Sr90) received by the Chernobyl
accident liquidators. erefore, it was not deemed possible to evaluate
the dierent eects of these radioactive atoms on the change of metal-
ligand homeostasis.
1. e epidermis derivative (hair) represents a convenient object
for noninvasive and retrospective supervision of events in
metal-ligand homeostasis epidermic cells, suitable for mass
(population) investigations. However, when conducting a
quantitative analysis of hair’s mineral structure, one should
avoid generalizing estimations by virtue of special, still
understudied role of epithelium in receipt and deducing of
metals. Moreover, one cannot exclude that in most cases
changes of metal concentration in epidermis can be of a re-
distribution nature, mismatching their true content in the
2. e correlation analysis of spectrometry data with the
subsequent selection of signicant correlations opens new
opportunities for studying metal-ligand homeostasis and
its changes connected with the redox status in organism (in
particular, with oxidative and nitrosative stress).
3. e results of the present work allow oer the following
parameters as kind of discriminators of an oxidizing and
nitrosative stress: a) increase in epidermis concentration values
K and Na alongside with reduction Ca and Zn, b) the presence
of signicant negative K-Zn correlations according to hair
spectrometry analyses.
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Citation: Petukhov VI, Dmitriev EV, Kalvinsh I, Baumane LKh, Reste ED, et al. (2011) Metal-Ligand Homeostasis in Epidermic Cells of Chernobyl
Accident Liquidators. Vitam Trace Elem 1:102. doi:10.4172/2167-0390.1000102
Page 8 of 8
Volume 1 • Issue 2 • 1000102
Vitam Trace Elem
ISSN: 2167-0390 VTE, an open access journal
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... Because of the impossibility to confirm the normal distribution hypothesis, one has to abandon the use of standard methods of estimating the mean value and use alternative approaches to this purpose: the bootstrap method [3], finding the median (Me) [4]. But when interpreting the results of hair spectrometry, it can be difficult to resist the illusion that the findings reflect the "elemental status" of the whole body [4], and not the features of the transmembrane metal traffic at the level of epidermocytes -a dynamic process which is susceptible to sharp numerical oscillations (judging by the CV). ...
... In the case of iron (Figure 4), the localization of these fragments of the curve acquires the opposite view: the subcritical state on the left, and the supercritical state on the right of the straight line along the abscissa axis.The explanation for this lies in the opposite effect of oxidative/nitrosative stress on the content of these metals in the epidermocytes. It is known that increased production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) can activate the membrane ATPases due to oxidative modification and/or nitrosylation of their molecules, which, according to our data, was accompanied by a significant decrease of Zn and Cu level in the cell, but by an increase of Fe[3,6].Therefore, the direction (sequence) of SC-periods (subcritical → critical → supercritical) by the content of metals and the increase in ATPase activity should be for zinc and copper -from higher concentration values to lower values, and for iron -from smaller to larger values. The resultant visual (and therefore with a certain approximation) numerical ranges of fragments approximated by a straight line (a critical state) were as follows: for zinc -200-1050 mcg/g, for copper 13-65 mcg/g, and for iron -15-50 mcg/g (Figures 2-4).It should be noted that the branching parameter σ in the oscillator system (in this case, membrane ATPases) is equal to the average number of the nearest 'neighbors' to which each of the oscillators can transmit the energy impulse (information). ...
... The linear positive Na-K bond (rNa-K=0.6-0.8; p<0.05) was detected by us both in healthy individuals (n=947) and in the liquidators of the Chernobyl accident (n=954), in which the signs of oxidative/nitrosativestress have been found[3].A reliable Na-K correlation, indicating synchronous operation of membrane Na + /K + -ATPase, was independent of the sample size, but was closely related to the current mode of membrane Na + /K + -ATPase functioning (critical, sub-and supercritical) or from the synchronous (critical status) and asynchronous (sub-and supercritical state) operation of these pumps. This is well illustrated by the values of rNa-K in the general group (n = 10012) and at the concentration values of K and Na, which correspond to the sub-and supercritical state (see ...
... We were able to verify the reality of such events by examining metal-ligand homeostasis (MLH) in the epidermis (hair) of 947 healthy individuals and 954 liquidators of the Chernobyl accident [4]. ...
... As follows from Table 3 with that of the Chernobyl liquidators (n=954) in relation to control (n=947) [4]. The value of SI in the general group of liquidators, as already mentioned, was also visibly higher than that of healthy individuals (6.13 vs 2.17) [11]. ...
... Therefore it cannot be ruled out that it is the increased production of ROS and RNS (oxidative/nitrosative stress) that is able to compensate for the lack of ATP due to a greater influx of other convertible energy currency into the cell, Na + ions, which becomes possible under these conditions with intensive Na + /K + -ATPase activity. The probability of such events may be indicated by our observations, in which the age-related dynamics of Na and K in the epidermis (spectrometry data) in 10297 healthy individuals were studied [2]. Two periods of a significant increase in the level of these metals in bio substrate were found: the first between 2 and 9 years of age; the second is from 60 to 85 years. ...
... Therefore, the critical (synchronous) operation of Na + /K + -ATPase can be indicated by a reliable (p <0.05) and stable (independent of the sample size) linear correlation between the Na and K in healthy individuals (r = 0.6) and emergency responders (r = 0.7) [2]. (Table 3) [3]. ...
... In our previous studies of MLH in a group of Chernobyl liquidators [5,6], we discovered that the content of such metals as Al, Cd, Fe, Cr, PB, V were higher, while the content of Cu and Zn were lower than the norm (Table 1). ...
Full-text available
The authors analyze the results of atomic emission spectrometry of hair samples for Al, Cd, Fe, Cr, Cu, Li, Pb, V, and Zn in 952 healthy subjects and 952 liquidators of the Chernobyl nuclear power plant accident. Using correlation analysis (Pearson) of the obtained data, the authors have found pair correlations between metal concentration values. According to the authors, criticality or synchronization (as a particular case of the critical state of the system) can be inherent in all ATP-dependent membrane pumps (P-type) controlling metal-ligand homeostasis in epidermal cells. A quantitative criterion (synchronization index) is proposed to measure the level of criticality (synchronization) in the functioning of membrane ATPases.
... Since 1994, data have been included in the Latvian State Register of Persons with Occupational Diseases and Persons Exposed to Radiation due to the CNPP Accident maintained by the specialists of the Centre of Occupational and Radiological Medicine (Pauls Stradiòð Clinical University Hospital). On the basis of information collected in the Centre four doctoral theses (Kurjane, 2001;Zvagule, 2004;Reste, 2013;Silova, 2015) and a lot of scientific studies were completed (Bruvere et al., 1995;Churbakova et al., 1996;Eglite et al., 1997;2009;Mironova et al., 1998;Kalnina et al., 2001;2012;2013;2013a;Kumerova et al., 2000;Kurjâne and Soèòevs, 1999;Kurjane et al., 1999;2000;Mazarevica et al., 2000;Mironova-Ulmane et al., 2001;2001a;Petukhov et al., 2011;Reste et al., 2012;2014;Skesters et al., 2005;2006a;2006b;2008;2010;2010a;Viel et al., 1997;Zvagule et al., 2002;. Clinical observations and epidemiological studies among Chernobyl recovery workers showed that these persons suffer from a broad spectrum of different kinds of diseases more seriously than in the non-exposed general Latvian population. ...
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The paper summarises the main findings on Chernobyl Nuclear Power Plant (CNPP) accident recovery workers from Latvia and their health disturbances, which have been studied by the authors during the last two decades. Approximately 6000 persons from Latvia participated in CNPP clean-up works in 1986–1991. During their work period in Chernobyl they were exposed to external as well as to internal irradiation, but since their return to Latvia they were living in a relatively uncontaminated area. Regular careful medical examinations and clinical studies of CNPP clean-up workers have been conducted during the 25 years after disaster, gathering knowledge on radiation late effects. The aim of the present review is to summarise the most important information about Latvian CNPP clean-up worker health revealed by thorough follow-up and research conducted in the period of 25 years after the accident. This paper reviews data of the Latvian State Register of Persons Exposed to Radiation due to CNPP Accident and gives insight in main health effects found by the researchers from the Centre of Occupational and Radiological Medicine (Pauls Stradiņš Clinical University Hospital) and Rīga Stradiņš University in a number of epidemiological, clinical, biochemical, immunological, and physiological studies. Latvian research data on health condition of CNPP clean-up workers in the late period after disaster indicate that ionising radiation might cause premature ageing and severe polymorbidity in humans.
... В Центре Биотической Медицины (г. Москва) методом атомно-эмиссионной спектрометрии на приборе Optima 2000 DV был сделан анализ минерального состава волос у 947 здоровых лиц (238 мужчин и 709 женщин в возрасте от 2 до 86 лет) и 954 ликвидаторов аварии на Чернобыльской АЭС -жителей Москвы (213 женщин и 741 мужчина в возрасте от 37 до 82 лет) [15]. Проверку гипотезы о нормальном распределении мы проводили с помощью теста Jarque-Bera [7] и теста Kolmogorov-Smirnov [13]. ...
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The article presents the results of the study of metal-ligand homeostasis (MLH) in the cells of the epidermis at 954 liquidators of accident at Chernobyl NPP and 947 practically healthy persons by means of atomic-emission spectrometry and EPR-analysis. Possible connection of redox status with the quantitative shifts in MLH is caused special interest. MLH can be used as discrimination of oxidation/nitrosative stress. Distinctive features of nitrosative stress concerned electrogenic metals (Ca, K, Na) and were found not only among the liquidators of the accident, but some of practically healthy persons. This may indicates the presence in these persons oxidation/nitrosative stress non-radiation nature. Revealed correlation of intracellular production of nitric oxide (NO) with quantitative shifts of electrogenic metals can testify to possible involvement of NO in the generation of electric potential (EP) of cell. Changes of EP on the background of oxidative/nitrosating stress were caused by the concentration shifts of electrogenic metals ions (primarily Ca2+), can, according to the authors, to wear an oscillatory character. The authors explain this by the fact that NO, Fe2+ ions and low-molecular thiols are able to form self-sustaining, self-regulating of chemical system, in which the S-nitrosothiols and dinitrosyl iron complexes with thiol-containing ligands appear continuously. Their mutual transformation provides vibrating level change of these compounds and is related to this process periodic oscillations of contents NO, NO+ (by type of reaction Belousov-Zhabotinsky).
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The doctoral thesis “The Aging Aspects of Humans Protractedly Exposed to Ionizing Radiation” is dedicated to the topical and still insufficiently investigated area of low-dose long-term radiation exposure effects on human aging processes. The use of ionizing radiation is progressively growing in various industries and technogenic accidents with release of huge amounts of radionuclides regularly happen worldwide. The most of the released radionuclides have long period of half-decay and increase the risk of protracted irradiation for inhabitants. It is important to realize the consequences of ionizing radiation exposure and understand in details the mechanisms of its effects on humans for timely resolving and prevention of radiation induced health problems. The aim of the study was to establish, if the persons, protractedly exposed to small doses of ionizing radiation, age faster and in a different way than chronically non-exposed humans. The work tasks included: the characterization of aging signs in humans protractedly exposed to small doses of ionizing radiation; the comparison of them with aging features of persons, who didn’t receive excessive exposure earlier in their life; and on the basis of study findings the development of practical recommendations for health care improvement. There were three study populations chosen: 1) Chernobyl nuclear power-plant (CNPP) accident clean-up workers from Latvia, whose organism accumulated certain amount of long-living radionuclides while working in Chernobyl, but after the return to Latvia these people were living in an area with relatively normal radioactivity level; 2) employees chronically exposed to ionizing radiation at work (radiologists, assistants of radiologists, X-ray laboratory assistants, etc.); 3) control group – Latvian inhabitants, who were not excessively exposed to ionizing radiation at work or in any other way previously in their life, except natural background and small medical X-ray examinations. Taking into account the complicated nature of aging, which cannot be characterized by one certain parameter, several aspects of irradiated humans’ senescence have been described in the doctoral thesis. Some different methods were used for realization of the current work: measurement of the relative telomere length in peripheral blood leukocytes by real-time quantitative polymerase chain reaction; detection of transforming growth factor β (TGFβ) level in blood serum by immune fermentative ELISA method; determination of the level of nitrogen oxide and iron in hair by electron paramagnetic resonance spectroscopy. Concurrently morbidity and mortality of CNPP clean-up workers were analysed in details, paying special attention to age-dependent diseases, including malignant neoplasms, and evaluating participation time and performed work tasks in Chernobyl. The results give evidence that aging processes in CNPP clean-up workers exceed the average rate of aging in general Latvian population. Moreover, the telomere shortening, normally seen in programmed replicative senescence, is not involved in the mechanism of aging of CNPP clean-up workers. The accelerated aging mechanism might be so called “stress induced premature senescence” due to ionizing radiation protracted exposure from incorporated radionuclides. It has been established that for formation of malignant neoplasm favourable conditions develop in the organism of humans chronically exposed to ionizing radiation. Slightly longer telomeres were found in CNPP clean-up workers comparing with other groups; in addition, significantly longer telomeres have been detected in persons with heavier radiation exposure. This probably indicates telomere lengthening ferment – telomerase – activation as the effect of permanent DNS damage from incorporated radionuclides, and may be an important factor for carcinogenesis. Significantly lower level of TGFβ was found in CNPP clean-up workers comparing with other groups, that reflects insufficient protection against malignancies in their organism. Similar tendencies, but much easier manifested, were observed in persons chronically irradiated at work, who have been working under radiation exposure for many years. Epidemiological study proved that CNPP clean-up workers, who were exposed to radiation during first year after disaster and performed more risky work with radioactive internal contamination, get ill with age-dependent disorders in younger age than others, but their mortality due to cardiovascular diseases in age group under 45 years exceeds age matched general Latvian male population mortality. Higher, comparing with general population, incidence of urogenital (prostate, kidney), thyroid and oral cavity malignant tumours was observed among young CNPP clean-up workers. On the other hand, oncologic mortality was lower in all age groups of CNPP clean-up workers comparing with non-exposed Latvian males, which indicates effective medical care of CNPP clean-up workers. Overall, it was established that protracted exposure to ionizing radiation is able to modify and accelerate aging processes in humans.
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ATP-sensitive potassium (KATP) channels in neurons regulate excitability, neurotransmitter release and mediate protection from cell-death. Furthermore, activation of KATP channels is suppressed in DRG neurons after painful-like nerve injury. NO-dependent mechanisms modulate both KATP channels and participate in the pathophysiology and pharmacology of neuropathic pain. Therefore, we investigated NO modulation of KATP channels in control and axotomized DRG neurons. Cell-attached and cell-free recordings of KATP currents in large DRG neurons from control rats (sham surgery, SS) revealed activation of KATP channels by NO exogenously released by the NO donor SNAP, through decreased sensitivity to [ATP]i. This NO-induced KATP channel activation was not altered in ganglia from animals that demonstrated sustained hyperalgesia-type response to nociceptive stimulation following spinal nerve ligation. However, baseline opening of KATP channels and their activation induced by metabolic inhibition was suppressed by axotomy. Failure to block the NO-mediated amplification of KATP currents with specific inhibitors of sGC and PKG indicated that the classical sGC/cGMP/PKG signaling pathway was not involved in the activation by SNAP. NO-induced activation of KATP channels remained intact in cell-free patches, was reversed by DTT, a thiol-reducing agent, and prevented by NEM, a thiol-alkylating agent. Other findings indicated that the mechanisms by which NO activates KATP channels involve direct S-nitrosylation of cysteine residues in the SUR1 subunit. Specifically, current through recombinant wild-type SUR1/Kir6.2 channels expressed in COS7 cells was activated by NO, but channels formed only from truncated isoform Kir6.2 subunits without SUR1 subunits were insensitive to NO. Further, mutagenesis of SUR1 indicated that NO-induced KATP channel activation involves interaction of NO with residues in the NBD1 of the SUR1 subunit. NO activates KATP channels in large DRG neurons via direct S-nitrosylation of cysteine residues in the SUR1 subunit. The capacity of NO to activate KATP channels via this mechanism remains intact even after spinal nerve ligation, thus providing opportunities for selective pharmacological enhancement of KATP current even after decrease of this current by painful-like nerve injury.
The standard tables used for the Kolmogorov-Smirnov test are valid when testing whether a set of observations are from a completely-specified continuous distribution. If one or more parameters must be estimated from the sample then the tables are no longer valid.A table is given in this note for use with the Kolmogorov-Smirnov statistic for testing whether a set of observations is from a normal population when the mean and variance are not specified but must be estimated from the sample. The table is obtained from a Monte Carlo calculation.A brief Monte Carlo investigation is made of the power of the test.
In this paper we study the performance of various tests for normality (N), homoscedasticity (H) and serial independence (I) of regression residuals (u) under one, two and three directional departures from HO:u∼NHI.
We use the Lagrange multiplier procedure to derive efficient joint tests for residual normality, homoscedasticity and serial independence. The tests are simple to compute and asymptotically distributed as χ2.
We postulate a novel and general mechanism in which the redox-active sulfur donor group of cyst(e)ine confers oxidoreductive characteristics on stable zinc sites in proteins. Thus, the present, an earlier, and accompanying manuscripts [Maret, W., Larsen, K. S. & Vallee, B. L. (1997) Proc. Natl. Acad. Sci. USA 94, 2233-2237; Jiang, L.-J., Maret, W. & Vallee, B. L. (1998) Proc. Natl. Acad. Sci. USA 95, 3483-3488; and Jacob, C., Maret, W. & Vallee, B. L. (1998) Proc. Natl. Acad. Sci. USA 95, 3489-3494] demonstrate that the interactive network featuring multiple zinc/sulfur bonds as found in the clusters of metallothionein (MT) constitutes a coordination unit critical for the concurrent oxidation of cysteine ligands and the ensuing release of zinc. The low position of MT (<-366 mV) on a scale of redox reagents allows its effective oxidation by relatively mild cellular oxidants, in particular disulfides. When MT is exposed to an excess of dithiodipyridine, all of its 20 cysteines are oxidized within 1 hr with the concomitant release of all 7 zinc atoms; similarly, the thiol/disulfide oxidoreductase DsbA reacts stoichiometrically with MT to release zinc. Zinc and sulfur ligands in the clusters are in a spatial arrangement that seemingly favors disulfide bond formation. Jointly, this and the above-mentioned manuscripts conclude that the control of cellular zinc distribution as a function of the energy state of the cell is the long sought role of MT. This specific MT function renders dubious the widely held belief that MT primarily scavenges radicals or detoxifies metals and is consistent with the frequent use of cysteine as a zinc ligand in proteins as a means of both tight and weak zinc binding of thiols and disulfides, respectively. Thus, we relate changes in the reducing power of the cell to the stability of the zinc/sulfur network in MT and the relative mobility of zinc and its control.
Effect of tumor necrosis factor-alpha (TNF), which is supposed to be one of the mediators responsible for endotoxin, on metallothionein (MT) synthesis was determined in various tissues of rats. At 18 hr after the injection of TNF, MT-I concentrations significantly increased in the liver, lung and heart, but not in the kidney and thymus. In the spleen of TNF-treated rats, MT-I concentrations decreased. Thus, synthesis of MT-I was tissue specific and dose-dependent. In the liver, the synthesis of both metallothionein-I and metallothionein-II was observed and the rate of the induction was greater in the latter. Antioxidative role of the MT synthesized by TNF was discussed.