The link between pain patient and analgesic medication is greater in migraine than in rheumatic disease patients.

Our aim was to measure and compare the link between pain patients and the different kinds of analgesic medications they use by the Leeds Dependence Questionnaire (LDQ). This is a self-completion 10-item instrument to measure the severity of dependence upon a variety of substances. LDQ was administered to 200 episodic migraine patients (EM group), 77 chronic migraine patients (CM group) overusing acute medications, and 114 patients suffering from rheumatic disease (RD group), consecutively attending the Headache Centre or the Rheumatology Clinic of the University Hospital of Modena in the course of the first semester of 2007. The link with analgesics was greater in migraine patients than in patients with rheumatic disease, since the LDQ total score was significantly higher in the EM (6.65 +/- 0.32, P < 0.005) and CM groups (9.61 +/- 0.59, P < 0.0001) than in the RD group (5.17 +/- 0.37) (Kruskal-Wallis and Mann-Whitney U-tests). Migraine patients were significantly more linked to triptans and to combined medications than to non-steroidal anti-inflammatory drugs. The strength of the link between migraine patients and the analgesic medications they take could represent a factor of vulnerability: overusing these medications could develop medication overuse headache.

Mitochondrial inner membrane permeability changes induced by octadecadienoic acid hydroperoxide. Role of mitochondrial GSH pool.

The effect of exogenous octadecadienoic acid hydroperoxide (HPODE) on the functional properties of inner membrane of isolated rat liver mitochondria, as evaluated by the measurement of the membrane potential (delta psi) has been studied. Very low concentrations of HPODE (1.5-4.5 nmol/mg prot.) do not modify the delta psi of control mitochondria appreciably while bringing about the drop of delta psi, in a concentration-dependent mode, in mitochondria with a GSH level diminished by approx. 60%. Mitochondrial GSH depletion was obtained by intraperitoneal administration of buthionine sulfoximine, a specific inhibitor of GSH synthesis, to rats. The presence in the incubation system of GSH-methyl ester which normalizes mitochondrial GSH, fully prevents any drop in levels of delta psi induced by HPODE. The same protective effect has been presented by EGTA, which chelates the available Ca2+. Neither an antioxidant nor a specific inhibitor of mitochondrial phospholipase A2 are able to prevent the HPODE effect. From the results obtained we can assume that HPODE itself, at the concentrations used here, induces permeability changes in the inner membrane, with the loss of coupled functions, when the GSH mitochondrial level is below a critical value.

Dietary iron deficiency in the rat. I. Abnormalities in energy metabolism of the hepatic tissue.

Severe iron deficiency was induced in rats by rearing nursing dams and their offspring on a diet comprising all the requisite nutrients and trace metals except iron. The iron deficient 5-week-old rats exhibited a severe anemia and a drastic decrease in iron content of the hepatic tissue and of the mitochondrial fraction. Cytochromes c + c1 and b were moderately but significantly reduced. A large increase in liver concentration was observed in iron-deficient animals; whereas there was no modification in total lipid, cholesterol, phospholipid and fatty acid composition of the mitochondrial membrane. Mitochondria from iron-deficient rats presented a partial uncoupling of the oxidative phosphorylation process. This functional derangement was completely reversed by the presence of either bovine serum albumin or L-carnitine plus ATP. This behaviour suggested that endogenous long-chain fatty acids could be primarily involved in the onset of mitochondrial dysfunction. The hepatic energy state of the liver appeared dramatically decreased under the pathological condition of severe iron-deficiency anemia. The possibility of a direct link between the partial loss of coupled functions observed in isolated mitochondria and the heavy energy deficit detected in the liver is discussed.

Dietary iron deficiency in the rat. II. Recovery from energy metabolism derangement of the hepatic tissue by iron therapy.

Severe iron deficiency in rats was found to be associated with abnormal lipid accumulation in the liver and impairment of the oxidative metabolism in the hepatic tissue. Iron therapy, consisting in oral administration to iron-deficient 4-week-old rats of iron succinyl-albumin complex, at a daily dose of 10 mg/kg body weight, over a period of 7 days, almost completely corrected these functional anomalies. This treatment fully reverted severe anemia associated with iron deficiency. The level of iron in the hepatic tissue and in the mitochondrial fraction also increased largely. By contrast, no significant improvement in the lowered level of cytochromes occurred. Iron supplements significantly decreased the abnormal level of liver total lipids and serum triglycerides. Concomitantly, iron repletion fully reverted the partial loss of coupled function in isolated mitochondria and the energy state perturbation of the liver. A close relationship among abnormal lipid accumulation, impairment of mitochondrial oxidative phosphorylation and energy derangement in the hepatic cell in this experimental model of severe dietary iron deficiency anemia appears to be likely.

Lipid hydroperoxide induced mitochondrial dysfunction following acute ethanol intoxication in rats. The critical role for mitochondrial reduced glutathione.

It has been found that acute ethanol (EtOH) intoxication of rats caused depletion of mitochondrial reduced glutathione (GSH) of approximately 40%. A GSH reduction of similar extent was also observed after the administration to rats of buthionine sulphoximine (BSO), a specific inhibitor of GSH synthesis. Combined treatment with BSO plus EtOH further decreased mitochondrial GSH up to 70% in comparison to control. Normal functional efficiency was encountered in BSO-treated mitochondria, as evaluated by membrane potential measurements during a complete cycle of phosphorylation. In contrast a partial loss of coupled functions occurred in mitochondria from EtOH- and BSO plus EtOH-treated rats. The presence in the incubation system of either GSH methyl monoester (GSH-EE), which normalizes GSH levels, or of EGTA, which chelates the available Ca2+, partially restores the mitochondrial phosphorylative efficiency. Following EtOH and BSO plus EtOH intoxication, the presence of fatty-acid-conjugated diene hydroperoxides, such as octadecadienoic acid hydroperoxide (HPODE), was detected in the mitochondrial membrane. Exogenous HPODE, when added to BSO-treated mitochondria, induced, in a concentration-dependent system, membrane potential derangement. The presence of either GSH-EE or EGTA fully prevented a drop in membrane potential. The results obtained suggest that fatty acid hydroperoxides, endogenously formed during EtOH metabolism, brought about non-specific permeability changes in the mitochondrial inner membrane whose extent was strictly dependent on the level of mitochondrial GSH.

Production of lipid hydroperoxides and depletion of reduced glutathione in liver mitochondria after acute ethanol administration to rats.

It has been found that acute ethanol (EtOH) intoxication to rats caused approximately 40% depletion of mitochondrial reduced glutathione (GSH). A GSH reduction of similar extent was also observed after the administration to rats of buthionine sulfoximine (BSO), a specific inhibitor of GSH synthesis. The combined treatment of EtOH plus BSO induced a further mitochondrial GSH decrease up to 70% with respect to control. The presence of lipid hydroperoxides in the mitochondrial membrane was observed whenever an additional oxidative stress was associated to a condition of GSH depletion as in the case of EtOH or EtOH plus BSO. Under these conditions a severe derangement in mitochondrial oxidative functions occurred.

Relationship between free iron level and rat liver mitochondrial dysfunction in experimental dietary iron overload.

The concentration of total iron in the hepatic tissue and mitochondria from rats fed a 2.5% carbonyl iron supplemented diet progressively increased up to 40 days, then reached nearly a steady-state. By contrast the level of free iron (desferrioxamine-chelatable) exhibited a transient but significant increase at 40 days of treatment, only in this period of treatment the induction of lipid peroxidation and the resulting mitochondrial abnormalities in calcium transport was observed too. The enhancement of the energy dissipating mitochondrial calcium cycling was found to be associated with a significant decrease of endogenous mitochondrial ATP content. As to the pathophysiological mechanism for hepatocellular injury in iron overload, these results indicated that the transit pool of free iron may play a critical role in initiating organelle dysfunctions, at least in this experimental model of iron overload.

Membrane potential of hepatic mitochondria after acute cocaine administration in rats--the role of mitochondrial reduced glutathione.

Cocaine hepatotoxicity may be mediated by oxidative damage, possibly involving mitochondrial injury. The effect of an acute dose of cocaine in rats on the mitochondrial level of reduced glutathione, nicotinamide adenine dinucleotide (NADH) and nicotinamide adenine dinucleotide phosphate (NADPH), important determinants in cellular defense against oxidative stress, was investigated. Under these conditions, the extent of lipid peroxidation was assessed as thiobarbituric acid reactive substances formation and the energy transducing capability of the inner mitochondrial membrane was evaluated by membrane potential measurements. Female Wistar albino rats were given an acute 50 mg/kg intraperitoneal dose of cocaine and, 6 hours later, hepatic and mitochondrial biochemical analyses were made. Rats administered intraperitoneally, 7.5 hours before the sacrifice, a specific inhibitor of glutathione synthesis, L-buthionine-(S,R)-sulphoximine, either alone or in combination with cocaine, underwent in parallel the same determinations. Cocaine intoxication did not impair mitochondrial functions, although a significant increase of lipid peroxidation occurred. By contrast the combination of L-buthionine-(S,R)-sulphoximine with cocaine induced a severe derangement of mitochondrial functional efficiency, a large depletion of reduced glutathione, and a further enhancement of lipid peroxidation. The mitochondrial functional anomalies were largely restored by the use of cyclosporin A, ethyleneglycotetraacetic acid (EGTA) and glutathione methylmonoester. A nonspecific calcium dependent inner membrane permeabilty transition (pore opening) accounted for the partial loss of mitochondrial coupled functions at a period of cocaine intoxication when no cell damage occurred. The level of mitochondrial glutathione played a critical role in protecting inner membrane functional integrity against cocaine-induced oxidative stress.

Antioxidant activity of silybin in vivo during long-term iron overload in rats.

BACKGROUND & AIMS: Hepatic iron toxicity may be mediated by free radical species and lipid peroxidation of biological membranes. The antioxidant property of silybin, a main constituent of natural flavonoids, was investigated in vivo during experimental iron overload. METHODS: Rats were fed a 2.5% carbonyl-iron diet and 100 mg.kg body wt-1.day-1 silybin for 4 months and were assayed for accumulation of hepatic lipid peroxidation by-products by immunocytochemistry, mitochondrial energy-dependent functions, and mitochondrial malondialdehyde content. RESULTS: Iron overload caused a dramatic accumulation of malondialdehyde-protein adducts into iron-filled periportal hepatocytes that was decreased appreciably by silybin treatment. The same beneficial effect of silybin was found on the iron-induced accumulation of malondialdehyde in mitochondria. As to the liver functional efficiency, mitochondrial energy wasting and tissue adenosine triphosphate depletion induced by iron overload were successfully counteracted by silybin. CONCLUSIONS: Oral administration of silybin protects against iron-induced hepatic toxicity in vivo. This effect seems to be caused by the prominent antioxidant activity of this compound.

'Free' iron, as detected by electron paramagnetic resonance spectroscopy, increases unequally in different tissues during dietary iron overload in the rat.

'Free' iron concentration, as determined by electron paramagnetic resonance (EPR) spectroscopy, and lipid peroxidation (LPO), as determined by thiobarbituric acid test, were assessed in the lung, heart, liver, spleen, brain and kidney of rats subjected to experimental iron overload. Two tests, Desferal- and NO-available iron, were used to measure 'free' iron and gave comparable results. The most pronounced accumulation of 'free' iron was observed in liver, kidney and spleen. Differences between control and iron loaded animals increased during the initial 90 days of treatment. Between 90 and 180 days 'free' iron concentration reached a steady state level, or even decreased, as in the case of liver. Lipid peroxidation level, measured in the organs of both treated and matched controls, did not give any significant difference during the initial 90 days of treatment. A significant augmentation was observed in liver, kidney, spleen and heart at 180 days. The results of the present research show that, under conditions of moderate siderosis, the occurrence of LPO is partially related to the level of 'free' iron.

A Medicago truncatula homoglutathione synthetase is derived from glutathione synthetase by gene duplication.

Glutathione (GSH) and homo-GSH (hGSH) are the major low-molecular weight thiols synthesized in Medicago truncatula. Two M. truncatula cDNAs (gshs1 and gshs2) corresponding to a putative GSH synthetase (GSHS) and a putative hGSH synthetase (hGSHS) were characterized. Heterologous expression of gshs1 and gshs2 cDNAs in an Escherichia coli strain deficient in GSHS activity showed that GSHS1 and GSHS2 are a GSHS and an hGSHS, respectively. Leucine-534 and proline-535 present in hGSHS were substituted by alanines that are conserved in plant GSHS. These substitutions resulted in a strongly stimulated GSH accumulation in the transformed E. coli strain showing that these residues play a crucial role in the differential recognition of beta-alanine and glycine by hGSHS. Phylogenetic analysis of GSHS2 and GSHS1 with other eukaryotic GSHS sequences indicated that gshs2 and gshs1 are the result of a gene duplication that occurred after the divergence between Fabales, Solanales, and Brassicales. Analysis of the structure of gshs1 and gshs2 genes shows they are both present in a cluster and in the same orientation in the M. truncatula genome, suggesting that the duplication of gshs1 and gshs2 occurred via a tandem duplication.