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Title
Impairment of mitochondrial respiration and electron transport
chain
enzymes during cocaine-induced hepatic inJury.
Author
Devi BG; Chan AW
Address
Research Institute on Addictions' New York State Office of Alcoholism
and Substance Abuse Services' Buffalo 14203-1016' USA.
Source
Life Sci, 60(11):849-55 1997
Abstract
Morphological and biochemical changes in mitochondrial have been
reported early in the course of cocaine-induced hepatotoxicity.
This
study was designed to examine the effects of repeated cocaine
exposure
in vivo on mitochondrial respiration' activities of respiratory
chain
enzymes' and lipid peroxide measures in liver. Male Sprague-Dawley
rats
were exposed to cocaine (5 i.p. inJections of 25 mg/kg; 3-day
period).
Blood and liver samples were taken' and hepatic mitochondria
were
isolated by differential centrifugation. The cocaine-treated
rats
developed oxidative stress in hepatic mitochondria as evidenced
by a
significant increase in malonaldialdehyde (MDA; 52%; p < 0.0001)
and a
decreased glutathione (GSH; 22%; p < 0.0003). Blood aspartate
aminotransferase (AST) and glutathione s-transferase (GST) levels
in
cocaine groups were significantly elevated (2.6 and 3.2 fold'
respectively; p < 0.0001 for both). Cocaine caused a decrease
in
state-3 respiration and respiratory control ratio (RCR) ratio
when
exposed to site I and II substrates; these changes were parallelled
by
a decrease in complex I (22%; p < 0.003)' succinate cytochrome
c
reductase (27%; p < 0.004)' and complex IV (24%; p < 0.003).
In
conclusion' functional abnormalities of hepatic mitochondria
accompany
lipid peroxidation caused by cocaine' supporting the hypothesis
that
the mitochondria is one of the maJor intracellular targets of
cocaine
hepatotoxicity.
Title
Myocardial injury after hypoxia in immature, adult and aged rats.
Author
Starnes JW; Bowles DK; Seiler KS
Address
Department of Kinesiology, University of Texas at Austin 78712,
USA.
Source
Aging (Milano), 9(4):268-76 1997 Aug
Abstract
We evaluated the abilities of isolated perfused hearts from immature
(IM) (2.5-3 months), ADULT (11-13 months) and OLD (24-26 months)
Fischer 344 rats to tolerate and recover from oxygen deprivation.
Hearts were perfused at 60 mmHg for a 30-minute prehypoxic period
with
oxygenated buffer supplemented with 10 mM glucose (+insulin)
and 2 mM
acetate, then 30 minutes with substrate-free, hypoxic buffer
gassed
with 95% N2:5% CO2, and finally reoxygenated for an additional
45
minutes with the same buffer used during the prehypoxic period.
During
prehypoxia, all groups were similar in ventricular mechanical
function,
glycogen content, high-energy phosphates (HEP), reduced glutathione
(GSH), Ca+2 content, and mitochondrial state 3 rates. At the
end of the
hypoxic period, glycogen levels were similar and almost completely
depleted in all groups, HEP were lower (p < 0.05) in ADULT
vs other
groups, mitochondrial state 3 rates were decreased (24%, p <
0.05) only
in ADULT, and GSH was depleted by 34% in IM vs only 13% in OLD
(p <
0.05). After 45 minutes of reoxygenation, IM and OLD had recovered
48%
and 45% of their respective prehypoxic function which was two-fold
greater than the 23% recovery by ADULT. Loss of cytosolic enzymes,
an
indicator of sarcolemmal damage, was estimated by measuring lactate
dehydrogenase (LDH) release. LDH release and Ca+2 content during
reoxygenation in IM were only about half of that observed in
ADULT or
OLD. We conclude that immature and aged hearts tolerate and recover
from hypoxia better than hearts from adults, and that the sarcolemmal
membranes of immature rat hearts are less susceptible to damage
from
hypoxic stress than those of either older group.
Title
Energy metabolism of spermatozoa during pronucleus formation
induced in
vitro by heparin-reduced glutathione. I. Glucose uptake.
Author
Reyes R; S]anchez-V]azquez ML; Delgado NM
Address
Unidad de Investigaci]on Biom]edica de Oriente' Centro M]edico
Nacional' General de Division Manuel Avila Camacho' Instituto
Mexicano
del Seguro Social' Puebla.
Source
Arch Androl, 30(1):73-7 1993 Jan-Feb
Abstract
Glycolitic metabolism under basal conditions and its modifications
by
the combined action of heparin and GSH were studied in human
sperm.
Respirometric data indicated that the amount of U. L. [14C -glucose
converted to 14CO2 increased with the incubation time' being
almost
linear for up to 60 min and then leveling off at 120 and 150
min (594
and 620 nmol of [14C -glucose/10(8) spermatozoa' respectively).
When
spermatozoa were incubated in the presence of heparin-GSH such
behavior
completely changed' showing a decrease (approximately 50%) in
glucose
metabolism with values of 254 and 366 nmol of [14C -glucose/10(8)
spermatozoa at the same incubation times as the basal consumption.
When
these results were compared with the kinetic of the swollen nuclei
it
was seen that at 30 min 44% of the spermatozoa have its nuclei
swollen
with a glucose uptake value of 91 nmol/10(8) spermatozoa' and
at 150
min when nearly all the spermatozoa nuclei are swollen (95%)
the
glucose uptake increases fourfold more than the initial rate
at 30 min.
Therefore' it is possible to suggest the existence of an energy
contribution by the sperm to the male pronuclei formation mechanism.
Title
Oxidation of intracellular glutathione after exposure of human
red
blood cells to hypochlorous acid.
Author
Vissers MC; Winterbourn CC
Address
Department of Pathology' Christchurch School of Medicine' New
Zealand.
Source
Biochem J, 307 ( Pt 1)():57-62 1995 Apr 1
Abstract
Exposure of human red blood cells to low doses of hypochlorous
acid
(HOCl) resulted in the loss of intracellular GSH. Oxidation occurred
less than 2 min after the addition of HOCl' and required approx.
2.5
mol of HOCl per mol of GSH lost. Loss of GSH preceded oxidation
of
membrane thiols' the formation of chloramines and haemoglobin
oxidation. The susceptibility of intracellular GSH to oxidation
by HOCl
was two-thirds that of GSH in cell lysates. These results indicate
that
HOCl can penetrate the red cell membrane' which provides little
barrier
protection for cytoplasmic components' and that GSH oxidation
by HOCl
may be a highly selective process. Virtually all of the GSH lost
was
converted into GSSG. If glucose was added to the medium' most
of the
GSH oxidized by low doses of HOCl was rapidly regenerated. At
higher
doses' recovery was less efficient. However' when HOCl was added
as a
slow infusion rather than in a single bolus' there was increased
recovery at higher doses. This indicates that in metabolically
active
cells regeneration is rapid and GSH may protect cell components
from
damage by HOCl. HOCl-induced lysis was only slightly delayed
by adding
glucose to the medium' indicating that lytic inJury is not ameliorated
by GSH.
Title
Changes in glutathione and cellular energy as potential mechanisms
of
papaverine-induced hepatotoxicity in vitro.
Author
Davila JC; Davis PJ; Acosta D
Address
Department of Pharmacology and Toxicology' College of Pharmacy'
University of Texas' Austin 78712-1074.
Source
Toxicol Appl Pharmacol, 108(1):28-36 1991 Mar 15
Abstract
The purpose of this study was to elucidate the mechanism of
hepatotoxicity of papaverine hydrochloride (papaver) in vitro.
To
evaluate the role of metabolism in the toxicity of papaver' cells
were
pretreated with SKF-525A or benzyl imidazole (cytochrome P450
system
inhibitors) for 24 hr at 1 x 10(-5) or 1 x 10(-4) M' respectively'
or
with phenobarbital sodium (cytochrome P450 system inducer) for
3 days
at 2 x 10(-3) M. Cells then were exposed to concentrations of
papaver
ranging from 1 x 10(-5) to 1 x 10(-3) M for 4 to 24 hr. Cytotoxicity
was evaluated by enzyme leakage (lactate dehydrogenase) and by
energy
status of the cells (ATP/ADP). The role of biological reactive
intermediates in the toxicity of papaver was investigated by
measuring
changes in cellular reduced glutathione levels (GSH)' by inhibiting
GSH
synthesis' and by determining the production of lipid peroxidation
(LPX). Papaverine produced concentration- and time-dependent
increases
in enzyme leakage' with significant effects occurring by the
8-hr
exposure period. Pretreatment with SKF-525A or benzyl imidazole
increased enzyme leakage induced by papaver especially at a later
time
frame (24 hr)' but pretreatment with phenobarbital delayed the
onset of
cytotoxicity from 8 to 12 hr. Decreases in GSH levels paralleled
the
time course of enzyme leakage. However' the administration of
buthionine sulfoximine to cell cultures dramatically decreased
the time
by which papaver induced cellular inJury (2 hr vs 8 hr). Changes
in
cellular energy status (ATP/ADP) were also detected earlier than
enzyme
leakage (4 hr vs 8 hr). In contrast' no significant production
of lipid
peroxidation was noted in papaver-treated cultures. We suggest
that the
mechanism of papaver-induced hepatotoxicity may be related to
alterations in glutathione balance of the cells and to disruption
of
energy homeostasis.
Title
Modulation of human microvascular endothelial cell bioenergetic
status
and glutathione levels during proliferative and differentiated
growth.
Author
Mallery SR; Lantry LE; Laufman HB; Stephens RE; Brierley GP
Address
Department of Pathology' College of Medicine' Ohio State University'
Columbus.
Source
J Cell Biochem, 53(4):360-72 1993 Dec
Abstract
During angiogenesis' formerly differentiated human microvascular
endothelial cells (HMECs) return to a proliferative growth state.
Many
fundamental questions regarding HMEC function' such as how HMECs
adapt
to changes in bioenergetic requirements upon return to proliferative
growth' remained unanswered. In this study' we evaluated whether
modifications in HMEC bioenergetic profiles and glutathione (GSH)
levels accompanied the cellular transition between differentiated
and
proliferative growth. To provide insight into the continuum of
cellular
adaptations that occur during this transition' we used a method
recently developed in our laboratory that induces a state of
morphological and functional predifferentiation in HMECs. Cellular
morphology' in conJunction with flow cytometric DNA analyses
and HMEC
functional assays (the directed migration and intercellular association
involved in microtubule formation) were employed to validate
the HMEC
culture state of growth. Analysis of the HPLC nucleotide profiles
disclosed several findings common to all culture growth states.
These
uniform findings' e.g.' cellular energy charges > 0.90' and
highly
reduced redox states' revealed that cultured HMECs maintain high
rates
of oxidative metabolism. However' there were also significant'
culture
growth state related differences in the nucleotide profiles.
Proliferative HMECs were shown to possess significantly higher
(relative to both large vessel endothelial cells' and differentiated
HMECs) levels of GSH and specific nucleotides which were related
with a
return to the active cell cycle-ATP' GTP' UTP' and CTP' and NADPH.
Further' the nucleotide profiles and GSH levels of the
predifferentiated HMECs were determined to be intermediate between
levels obtained for the proliferative and differentiated HMECs.
The
results of this study demonstrate that the capacity to modulate
their
cellular bioenergetic status during growth state transitions
is one of
the adaptations that enable HMECs to retain a growth state reciprocity.
In addition' our findings also show that HMECs' especially during
the
proliferative growth state' are biochemically distinct from endothelial
cells harvested from large vessels' and therefore suggest that
HMECs
are the cells of choice to employ when studying diseases that
affect
the human microvasculature.
Title
Depletion of cytosolic GSH decreases the ATP levels and viability
of
synaptosomes from aged mice but not from young mice.
Author
Mart]inez M; Ferr]andiz ML; D]iez A; Miquel J
Address
Instituto de Neurociencias' Facultad de Medicina' Universidad
de
Alicante' Spain.
Source
Mech Ageing Dev, 84(1):77-81 1995 Sep 29
Abstract
The effect of glutathione depletion on the viability of freshly
isolated synaptosomes from whole brain was investigated in young
and
aged mice. Aging did not influence the GSH and ATP levels and
the
viability of these synaptosomes. However depletion of glutathione
caused by the cytosolic glutathione inhibitor diethyl maleate
(1 mM)
resulted in a significant decline' after 60 min of incubation'
in ATP
levels and viability in the synaptosomes from aged mice but not
in
those from young mice. When synaptosomes were incubated in the
presence
of the mitochondrial glutathione inhibitor ethacrynic acid (0.2
mM)
there was a similar decline in glutathione' ATP levels and synaptosomal
viability' both in young and aged mice. These results emphasize
the
relative importance of the cytosolic glutathione pool for the
maintenance of the plasma membrane integrity in synaptosomes
from aged
mice.
Title
Excessive liver oxidant stress causes mortality in response to
burn
inJury combined with endotoxin and is prevented with antioxidants.
Author
LaLonde C; Nayak U; Hennigan J; Demling RH
Address
Brigham & Women`s Hospital' Boston' Massachusetts 02115'
USA.
Source
J Burn Care Rehabil, 18(3):187-92 1997 May-Jun
Abstract
We studied the effect of the oral administration of a water-soluble
antioxidant solution containing ascorbic acid' glutathione' and
a
precursor for glutathione synthesis' N-Acetyl-L-cysteine' on
liver
antioxidant activity' liver cell energetics' and mortality in
rats in
response to a 20% third-degree burn inJury challenged 5 days
later with
an intraperitoneal inJection of 30 mg/kg endotoxin. Rats with
burns
were fluid-resuscitated with subcutaneous Ringer`s lactate solution
according to the Parkland formula (4 cc/kg/%burn). Rats challenged
with
endotoxin 5 days after burn were given an additional 100 ml/kg
of
subcutaneous Ringer`s lactate solution immediately after the
inJection
of endotoxin. A group of rats with burns challenged with endotoxin
5
days after burn were given an oral antioxidant solution beginning
after
burn inJury. Liver cell energetics were measured as tissue energy
charge potential (ECP)' adenosine triphosphate (ATP) content'
and total
adenine nucleotides. The levels of endogenous liver glutathione'
catalase' vitamin C' and vitamin E were measured to monitor antioxidant
status. We found that burn inJury alone did not produce any mortality
over the 6-day period despite a 35% decrease in liver energy
charge
potential resulting from a decrease in ATP' a 34% decrease in
liver
catalase activity' and a 20% decrease in liver vitamin C. It
was
interesting that glutathione increased and vitamin E remained
unchanged. We found that endotoxin inJury combined with burn
inJury
produced a 61% mortality rate with a 63% decrease in liver energy
charge potential' again resulting from a decrease in ATP' a 74%
decrease in liver catalase activity' a 16% decrease in vitamin
C' and a
29% decrease in vitamin E. glutathione was significantly decreased
compared with burn alone. We compared the liver antioxidant status
of
survivors with that of nonsurvivors who were killed when appearing
moribund and found that glutathione was decreased by 51% and
vitamin C
by 73% in nonsurvivors over that in survivors' whereas catalase
and
vitamin E levels were comparable between the two groups. The
oral
administration of the antioxidants prevented mortality and the
decrease
in antioxidant activity and attenuated the decrease in energy
charge
potential.We conclude that a 20% burn produces a modest decrease
in
liver energy charge potential and antioxidant defenses without
producing mortality. The addition of endotoxin further decreases
liver
antioxidant defenses' liver energy charge potential' and markedly
increases mortality. Antioxidants' given post-burn' restored
antioxidant defenses' attenuated the altered cell energetics'
and
prevented mortality' indicating oxidants to be the cause of mortality.
This data also suggests that a critical value of decreases in
antioxidant defenses and ATP exists' resulting in mortality.
Title
Blood levels of reduced/oxidized glutathione and plasma concentration
of ascorbic acid during eccentric and concentric exercises of
similar
energy cost.
Author
Camus G; Felekidis A; Pincemail J; Deby-Dupont G; Deby C; Juchmes-Ferir
A; LeJeune R; Lamy M
Address
Laboratory of Human Applied Physiology' University of Li`ege.
Belgium.
Source
Arch Int Physiol Biochim Biophys, 102(1):67-70 1994 Jan-Feb
Abstract
In an attempt to assess the possible oxidative stress associated
with
the transient exercise-induced activation of polymorphonuclear
neutrophils (PMN)' we compared the effects of eccentric and concentric
exercises (downhill run: DR and uphill walk: UW' respectively)
of equal
duration (35 min) and similar energy cost (60% VO2max) on plasma
levels
of ascorbic acid ([AA ) and blood concentration of reduced ([GSH
) and
oxidized ([GSSG ) glutathione. Eight healthy male subJects took
part in
this study. Plasma concentration of myeloperoxidase ([MPO ) was
used as
a specific marker of PMN activation. While there were no significant
changes in [MPO and [AA in UW experiments' [MPO increased (+80%)
and
[AA decreased significantly during DR tests (P < 0.01 and
P < 0.05'
respectively). A significant negative relationship was observed
between
[AA and [MPO in DR experiments only (r = -0.49; P < 0.01).
Mean (+/-
SEM) basal GSH and GSSG concentrations' calculated by pooling
the
values measured before both tests' were 0.54 +/- 0.02 and 0.12
+/-
0.007 mM' respectively. The blood concentration of these compounds
remained practically unchanged in both exercise tests. These
results
confirm the role played by the eccentric component of muscle
contraction in transient exercise-induced PMN activation and
suggest
that this activation was partly involved in the decrease in [AA
observed in DR experiments. The oxidant stress associated with
the
exercise protocol used in this study was insufficient to alter
blood
levels of reduced and oxidized glutathione.
Title
Some characteristics of the glutathione cycle revealed by ionising
and
non-ionising electromagnetic radiation.
Author
Holt JA
Address
Microwave Therapy Centre' West Perth' Australia.
Source
Med Hypotheses, 45(4):345-68 1995 Oct
Abstract
The cyclic reaction of GSH-->GSSG-->GSH (designated R(exp)
or R(e))
obeys the three specific features of life by producing energy
in
exponential quantities relative to time' is in effect irreversible
and
is inherited from generation to generation. In multicellular
life' this
reaction produces the energy for mitosis and is kept in controlled
inactivity until needed to maintain perfection of form and function
by
energising mitosis. The immediate control of Re appears to be
feedback
process-dependent on the concentration of GSSG. Ultra high-frequency
electromagnetic radiation of 434 MHz (UHF) will change Re from
inactive
to active and' in so doing' it causes resonance and/or fluorescence
of
the glutathione cycle which changes its radiosensitivity. Re
is the
primary direct target of ionising radiation and produces the
energy for
mitosis. Clinical observations suggest that' in the normal cell'
Re is
inactive and is not killed by 3 x 2700 rads or 6 x 1650 rads
yet' when
active' its sensitivity value (DO) is approximately 160 rads.
Using the
standard radiobiological equation of response to ionising radiation'
it
can be deduced that radiosensitive cancers have two or three
Re units
active per cell and radioresistance increases in proportion to
the
number of potentially active Re units per cell. Re appears to
be the
main cause of cancers` increased conductivity of electricity
compared
with normal tissue. In cancer therapy' UHF is the best radiosensitiser
ever discovered (up to two or more decades). Re is also intelligent
compared with non-exponential reactions but cannot be the basis
of
intellectual brain functions which must be based on non-electrical
chemical processes.
Title
Cytokine toxicity and induction of NO synthase activity in cultured
mouse hepatocytes.
Author
Adamson GM; Billings RE
Address
Department of Surgery' School of Medicine' University of Nevada'
Reno
89557
Source
Toxicol Appl Pharmacol, 119(1):100-7 1993 Mar
Abstract
Interferon-gamma (IFN-gamma) has been shown to exacerbate tumor
necrosis factor alpha (TNF alpha)-induced hepatotoxicity in vivo
as
well as act synergistically with TNF alpha in a variety of biological
actions. In the present study we have examined interactions of
IFN-gamma with TNF alpha and the role of nitric oxide synthase
(NOS)
activity in the generation of an intracellular oxidant stress
in
isolated mouse hepatocytes. Exposure to either IFN-gamma or TNF
alpha
significantly increased NOS activity. In combination' TNF alpha
and
IFN-gamma markedly increased NOS activity beyond that expected
for a
merely additive effect. IFN-gamma potentiated TNF alpha-induced
effects
on the hepatocyte glutathione pool' increasing the extent of
GSH
depletion and GSSG efflux. Furthermore' IFN-gamma exacerbated
TNF
alpha-induced ATP depletion. Exposure to both TNF alpha and IFN-gamma
resulted in significant cytotoxicity in hepatocytes' whereas
neither
cytokine alone produced any toxicity. TNF alpha-induced cytotoxicity
in
hepatocytes pretreated with 1'3-bis (chloroethyl)-1-nitrosourea
(BCNU'
a glutathione reductase inhibitor) was potentiated by IFN-gamma.
TNF
alpha/IFN-gamma-induced GSSG efflux was prevented when hepatocytes
were
treated with the antioxidant mannitol. Furthermore' mannitol
reduced
the extent of ATP depletion as well as cytotoxicity induced by
TNF
alpha and IFN-gamma in either BCNU- or non-BCNU-treated hepatocytes.
In
contrast' mannitol abolished cytotoxicity in BCNU-treated cells
exposed
to TNF alpha alone. Thus' mannitol provides significant protection
against deleterious oxidative effects induced by IFN-gamma and
TNF
alpha. However' IFN-gamma also appears to potentiate the deleterious
effects of TNF alpha' at least in part' by mechanisms other than
an
increase in oxygen radical generation. Using the methylated analog
of
arginine' NG-monomethyl-L-arginine' to inhibit NOS activity'
it was
demonstrated that TNF alpha/IFN-gamma-induced ATP depletion'
GSSG
efflux' and cytotoxicity were not dependent upon the stimulation
of
NOS. Furthermore' significant increases in NOS activity did not
occur
until after 4 hr of exposure to either cytokine' whereas GSSG
efflux
and ATP depletion occurred during the first 4 hr of incubation.
Taken
together' these results indicate that IFN-gamma acts synergistically
with TNF alpha' resulting in the potentiation of an intracellular
oxidative stress' inhibition of energy metabolism' and cytotoxicity.
However' these events do not appear to be related to an increase
in NOS
activity.
Title
Reoxygenation inJury of rat hepatocytes: evaluation of nucleotide
depletion and oxidative stress as causal components.
Author
Grune T; Schneider W; Siems WG
Address
Klinik f ur Physikalische Medizin und Rehabilitation' Humboldt
Universit at zu Berlin' Federal Republic of Germany.
Source
Cell Mol Biol (Noisy-le-grand), 39(6):635-50 1993 Sep
Abstract
Isolated rat hepatocytes were used for the evaluation of nucleotide
depletion and oxidative stress as two causal components of postischemic
inJury following oxygen deficiency. The ATP and GTP loss during
anoxia
was accompanied by temporary increases of nucleotide degradation
products. The critical duration of anoxia for a complete ATP
restoration during reoxygenation was between 30 and 60 min. The
oxidative stress during reoxygenation was demonstrated by decrease
of
GSH concentration and increase of TBA-RS level. The tremendous
GSH loss
could not be balanced by the slight GSSG increase during reoxygenation.
Prevention of GSH decrease and TBA-RS increase in parallel to
prevention of viability loss in presence of oxipurinol in contrast
to
lacking improvement of ATP and GTP restoration by this drug speak
in
favor for the oxidative stress as maJor causal component for
postischemic inJury of hepatocytes in comparison with depletion
of
energy-rich purine nucleotides. The inhibition of formation of
reactive
oxygen species via xanthine oxidase reactions was found to be
the
dominant protective effect of oxipurinol against postischemic
inJury of
hepatocytes in comparison with lacking influence on nucleotide
salvage
and ATP/GTP regeneration and with radical scavenging. |
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