6118Mid- and long-term percentage of ventricular pacing in patients implanted with a pacemaker after a transcatheter aortic valve replacement procedure: potential clinical implications

Background

Cardiac conduction disturbances frequently occur following transcatheter aortic valve replacement (TAVR). As this procedure is getting more and more common, more research efforts should focus on post procedural rhythm disturbances and their evolution over time

Purpose

To evaluate the percentage of pacing in patients who underwent a TAVR procedure and developed a conduction disturbance requiring a transvenous pacemaker (PM) implantation

Methods

We considered all the patients who underwent a TAVR procedure between march 2009 and november 2018 in our centre. Patients implanted with a PM or an ICD before the TAVR procedure or 30 days after the TAVR were not considered eligible for our analysis, because likely not related to TAVR. The percentage of effective right ventricular pacing was assessed both at mid- and long-term follow-up

Results

265 patients underwent TAVR in the study period (45% males, 81±6 years). 20 patients already had a PM and were excluded. 39 of the 245 patients (16%) were implanted with a PM after TAVR, 26 of them were implanted within 30 days (median time TAVR-PM implant: 8±7 days). The rate of PM implant within 30 days after TAVR was 8% (20/246) for patients implanted with an Edward Sapien valve, 25% (4/16) for patients with an Evolute Pro valve and 66% (2/3) in patients with a Lotus Edge valve. The indication for PM implant was a permanent 3rd degree A-V block in 12 patients, a paroxysmal A-V block in 4, a bifascicular A-V block with an infra-hisian disease in 5, a II degree Mobitz II A-V block in 2, an atrial fibrillation with slow A-V conduction in 2 and a 2:1 A-V block with infra-hisian disease in 1. The first follow-up after the PM implantation was available in 24 patients (mean 78±87 days after PM implant) and the second in 15 patients (372±267 days after PM implant). The patients were divided into two groups based on the presence/absence of permanent 3rd degree AV block at the time of implantation. At the first follow-up the percentage of pacing was significantly higher in patients implanted with vs. without a permanent 3rd degree AV block (98.5% vs 11%, p<0.001). Notably, in none of the patients without a permanent 3rd AV block at baseline conduction disturbances progressed toward a permanent AV block during long-term follow-up. Accordingly, at the second follow-up patients without permanent 3rd AV block at baseline showed a significantly lower percentage of pacing (1% vs 100%; p<0.01)

Conclusion

Patients implanted with a PM after TAVR in the absence of a permanent 3rd AV block have a very low likelihood of progression to a permanent AV conduction disturbance and show a negligible percentage of pacing during follow-up. Our results may impact the choice of the correct timing of PM implantation after TAVR and the potential indication for a leadless PM.

Blond and blood juice supplementation in high fat diet fed mice: effect on antioxidant status and DDAH/ADMA pathway

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease spread throughout the world. The most frequent causes of death in NAFLD patients are due both to liver and cardiovascular damage. Several pathways, including the dimethylarginine dimethylaminohydrolase (DDAH)/asymmetric dimethylarginine (ADMA) pathway, are involved in the pathogenesis of NAFLD. It has been reported that ADMA plasmatic levels are increased in patients with hepatic dysfunction such as NAFLD. Although many studies demonstrated that some foods are effective in the treatment of NAFLD, few studies have evaluated their effects with respect to the prevention of the disease. It has been reported that sweet orange juice (OJ) consumption may be associated with potential health benefits. However, some varieties of sweet orange are more effective than others. The aim of the present paper was to investigate the effect of blond and blood sweet orange juice in prevention of NAFLD by evaluating its ability to improve liver steatosis in mice with diet-induced obesity, reducing oxidative stress and affecting the DDAH/ADMA pathway. Results obtained in our experimental conditions evidenced that blood orange juice rather than blond orange juice was more effective. Blood orange juice or blond orange juice enriched in anthocyanins may represent a promising dietary option for the prevention of fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease spread throughout the world.

Oxidative profile in patients with colon cancer: effects of Ruta chalepensis L

AIM

To verify the involvement of free radicals in tumor progression and to investigate the effects of an ethanolic extract of Ruta Chalepensis L. and of rutin in blood of patients with colon cancer.

MATERIALS AND METHODS

Leaves of Ruta Chalepensis L. were collected in the area around Catania (Italy). For the preparation of the ethanol extract of leaves, an exhaustive extraction of 100 g of the drug was carried out in Soxhlet with 800 ml of 95% ethanol. Fifty-six patients with colorectal cancer were randomly selected for this study; among these, 34 were affected by an early stage (T1 N0 M0 according to scale), while 22 were affected by an advanced stage (T4, N1-2, M0) of cancer. Data obtained from these patients were compared with those of a control group consisting of 20 healthy subjects. Plasma of each sample was used for determining non-proteic antioxidant capacity, thiol groups, lipid hydroperoxides and nitrite/nitrate levels, evaluated by spectrophotometric tests. In addition, percentage of haemolysis was evaluated incubating (for 2 hours at 37 degrees C) erythrocyte suspension with a free radical donor (50 mM 2,2'-azobis-amidino propane chloridrate), in the presence or absence of ethanolic extract of Ruta Chalepensis L. (250 microg/ml) or rutin (1 mM).

RESULTS

Non-proteic antioxidant capacity was significantly lower in cancerous patients than in healthy subjects (p < 0.001). This decrease was stage-related. In fact, non-proteic antioxidant capacity resulted lower in advanced than in early colorectal cancer (p < 0.001). The same significant stage-related decrease was observed in plasma thiol groups (p < 0.001). Coherently with the decrease in non-proteic antioxidant capacity and thiol groups, higher levels of lipid hydroperoxides and nitrite/nitrate were observed in patients with colorectal cancer with respect to healthy subjects (p < 0.001) and the increase in these markers of oxidative stress was related to the cancer stadiation. Neoplastic patients also showed an increased percentage of oxidative hemolysis respect to controls and the haemolytic damage was correlated with the stage of colon cancer. Both the extract of Ruta Chalepensis L. and rutin were able to protect erythrocytes from oxidative stress induced by the free radical donor, but the extract of Ruta Chalepensis L. was more effective than rutin. This protective effect was significant only in erythrocytes from patients with early colorectal group, whereas no significant modification was induced by Ruta Chalepensis L. or rutin in red blood cells from advanced colorectal cancer patients exposed to the same experimental conditions.

CONCLUSION

Oxidative stress correlates with colon cancer stadiation and both the extract of Ruta chalepensis and rutin are able to protect red blood cells from radical-induced damage. However, their effects are significant in early stages of cancer. So these natural antioxidants might be usefull to prevent carcinogenesis and/or tumor progression.

Antioxidant properties of anesthetics: the biochemist, the surgeon and the anesthetist

General anesthesia can impair immunological defense mechanisms while inducing an inflammatory reaction. Generalized inflammatory reactions involve leucocytes which in turn release inflammatory mediators and free oxygen radicals. General anesthetics include a series of gaseous and intravenous sedative-hypnotic agents indicated for induction and maintenance of general anesthesia as well as for sedation of intubated, mechanically ventilated adults in intensive care units (ICU). Some anesthetics, such as propofol, are characterized by a phenolic structure similar to that of alpha-tocopherol, and exhibit antioxidant properties that have been demonstrated both in vitro and in vivo. Similarly, other anesthetics show antioxidant and protective roles but this mechanism is to be related to their ability to induce antioxidant enzyme (i.e., heme oxygenase-1). The aim of the present review is to evaluate the antioxidant properties of anesthetics in various experimental models and if they may be considered efficient therapeutic tools in counteracting oxidative stress during general anesthesia and sedation in ICU.

Role of carbon monoxide and biliverdin in renal ischemia/reperfusion injury

Heme oxygenase (HO) isoforms catalyze the conversion of heme to carbon monoxide (CO) and biliverdin/bilirubin with a concurrent release of iron. There is strong evidence that HO activity and products play a major role in renoprotection, however the exact molecular mechanisms underlying the beneficial effects exerted by this pathway are not fully understood. This review is aimed at illustrating the possible mechanism/s by which HO is renoprotective in the context of ischemia/reperfusion. We will first analyze the effects of exogenous administration of bilirubin/biliverdin and CO and then describe their biological activities once generated endogenously following stimulation of the HO pathway by either pharmacological means or gene targeting-mediated approaches.

Imidazole derivatives as antioxidants and selective inhibitors of nNOS

The reperfusion of ischemic tissue often delays its physiological and functional recovery; this paradoxical effect is ascribed to increased release of free radicals including O(2)(-) and NO. For these reasons, scavenging reactive oxygen species or inhibition the NO synthesis has been shown to result in an enhanced neuronal survival after cerebral ischemia. Many authors believe that therapy for stroke patients would be a cocktail of drugs with various mechanisms of action. Combination therapy is a difficult and complicated avenue for drug development because of the possibility of drug-drug interactions. An alternative approach would be to combine multiple activities within the same compound. In consideration of the free-radical scavenging and inhibitory effect on NOS of various natural and synthetic compounds, the aim of this study was to analyze the antioxidant properties of some imidazole derivatives previously synthesized in our laboratory. Results obtained in the present study provide evidence that tested compounds exhibit interesting antioxidant properties, expressed either by their capacity to scavenge free radicals or their ability to reduce lipid peroxidation. In particular, compounds A and B represent chemical structures which can be easily modified to improve the observed antioxidant properties and to provide new therapeutic strategies focused on multiple downstream events.

Effects of norepinephrine depletion in rats during cerebral post-ischemic reperfusion

The present paper reports the effects of norepinephrine depletion in rats, after treatment with N-(2-chloroethyl)-N-ethyl 2-bromobenzylamine (DSP-4) neurotoxin, on partial cerebral ischemia and reperfusion. Histological observations made under experimental conditions of noradrenergic (NA)-depletion demonstrated that neuronal lesions were not exacerbated; in fact, in DSP-4-treated ischemic animals, a minor number of neurons appeared damaged. Our results suggest that neuronal recovery after post-ischemic reperfusion is not affected by NA-depletion. DSP-4 neurotoxin does not induce 5-hydroxy-triptamine (5-HT) depletion.

Novel inhibitors of neuronal nitric oxide synthase

Selective inhibitors of neuronal nitric oxide synthase (nNOS), which are devoid of any effect on the endothelial isoform (eNOS), may be required for the treatment of some neurological disorders. In our search for novel nNOS inhibitors, we recently described some 1-[(Aryloxy)ethyl]-1H-imidazoles as interesting molecules for their selectivity for nNOS against eNOS. This work reports a new series of 1-[(Aryloxy)alkyl]-1H-imidazoles in which a longer methylene chain is present between the imidazole and the phenol part of molecule. Some of these molecules were found to be more potent nNOS inhibitors than the parent ethylenic compounds, although this increase in potency resulted in a partial loss of selectivity. The most interesting compound was investigated to establish its mechanism of action and was found to interact with the tetrahydrobiopterin (BH(4)) binding site of nNOS, without interference with any other cofactors or substrate binding sites.

Lack of prognostic significance in Goseki grading of gastric carcinoma

The Goseki grading system, based on intracellular mucin content and tubular differentiation, was originally created to study the influence of histologic type on the mode of extension of gastric carcinoma. The prognostic value of this grading system was subsequently proposed and even recently supported, but controversies still remain about this topic. We applied the Goseki system on 114 cases of node-negative primary gastric cancer and compared Goseki groups with the other clinicopathologic features of the patients. Statistical analysis showed a significant correlation between Goseki grading and Laurèn classification, but failed to reveal any prognostic significance for this grading system. We believe that Goseki classification should not be routinely used for prognostic purposes.

Progress in the development of selective nitric oxide synthase (NOS) inhibitors

Nitric oxide (NO), a molecular messenger synthesized by nitric oxide synthase (NOS) from L-arginine and molecular oxygen, is involved in a number of physiological and pathological processes in mammalians. Three structurally distinct isoforms of NOS have been identified: neuronal (nNOS), endothelial (eNOS) and inducible (iNOS). Although NO mediates several physiological functions, overproduction of NO by nNOS has been reported in a number of clinical disorders including acute (stroke) and chronic (schizophrenia, Alzheimer s, Parkinson s and AIDS dementia) neurodegenerative diseases, convulsions and pain; overproduction of NO by iNOS has been implicated in various pathological processes including septic shock, tissue damage following inflammation and rheumatoid arthritis. On the contrary, NO produced by eNOS has only physiological roles such as maintaining physiological vascular tone. Accordingly, selective inhibition of nNOS or iNOS vs eNOS may provide a novel therapeutic approach to various diseases; in addition selective inhibitors may represent useful tools for investigating other biological functions of NO. For these reasons, after the identification of N-methyl-L-arginine (L-NMA) as the first inhibitor of NO biosynthesis, design of selective NOS inhibitors has received much attention. In this article the recent developments of new molecules endowed with inhibitory properties against the various isoforms of NOS are reviewed. Major focus is placed on structure-activity-selectivity relationships especially concerning compounds belonging to the non-amino acid-based inhibitors.

Expression of bone morphogenetic protein-6 and transforming growth factor-beta1 in the rat brain after a mild and reversible ischemic damage

We have examined the distribution of transforming growth factor-beta1 (TGF-beta1) and bone morphogenetic protein-6 (BMP-6) in the brain of rats subjected to a mild and reversible ischemic damage produced by a 20-min occlusion of both carotid arteries without occlusion of the vertebral arteries. We have selected this model to study how the expression of trophic factor of the TGF-beta superfamily changes in neurons that recover from a transient insult. Immunocytochemical analysis showed a loss of TGF-beta1 in neurons of all hippocampal subfields immediately after the ischemic period, followed by a recovery of immunoreactivity in CA1 and CA3 neurons after reperfusion. BMP-6 immunoreactivity was also lost in most hippocampal neurons, but immunostaining became particularly intense in the interstitial space after both ischemia and reperfusion. An interstitial localization of BMP-6 was also observed in the cerebral cortex, particularly after reperfusion. Mild ischemia also induced substantial changes in the expression of TGF-beta1 and BMP-6 within the cerebellar cortex. In control animals, these factors appeared to be localized in granule cells (TGF-beta1) and Purkinje cells (both), whereas the molecular layer was not immunopositive. Both TGF-beta1 and BMP-6 were highly expressed in the interstitial spaces of the cerebellar cortex either 20 min after ischemia or 20 min after reperfusion. Taken collectively, these results suggest that a mild and reversible ischemia stimulates the release of BMP-6 from neurons into the interstitial space. We speculate that BMP-6, besides functioning during brain development, may also regulate neuronal resistance to insults of the adult brain.

L -propionyl-carnitine as superoxide scavenger, antioxidant, and DNA cleavage protector

L-Propionylcarnitine, a propionyl ester of L-carnitine, increases the intracellular pool of L-carnitine. It exhibits a high affinity for the enzyme carnitine acetyltransferase (CAT) and, thus, is readily converted into propionyl-coenzyme A and free carnitine. It has been reported that L-propionylcarnitine possesses a protective action against heart ischemia-reperfusion injury; however, the antioxidant mechanism is not yet clear. L-Propionylcarnitine might reduce the hydroxyl radical production in the Fenton system, by chelating the iron required for the generation of hydroxyl radicals. To obtain a better insight into the antiradical mechanism of L-propionylcarnitine, the present research analyzed the superoxide scavenging capacity of L-propionylcarnitine and its effect on linoleic acid peroxidation. In addition, the effect of L-propionylcarnitine against DNA cleavage was estimated using pBR322 plasmid. We found that L-propionylcarnitine showed a dose-dependent free-radical scavenging activity. In fact, it was able to scavenge superoxide anion, to inhibit the lipoperoxidation of linoleic acid, and to protect pBR322 DNA from cleavage induced by H2O2 UV-photolysis.

Bioflavonoids as antiradicals, antioxidants and DNA cleavage protectors

Flavonoids have recently aroused considerable interest because of their broad pharmacological activity. In fact, flavonoids have been reported to have antiviral, antiallergic, antiplatelet, anti-inflammatory and antitumoral activities. The pharmacological properties of bioflavonoids have been ascribed both to the concomitant inhibition of enzymes involved in the production of free radicals and to their free-radical scavenging and iron chelating capacity. However the antioxidant capacity of bioflavonoids due to free-radical scavenging and/or to iron chelating is still controversial. In this study, we have investigated the free-radical scavenging capacity of bioflavonoids (rutin, catechin, and naringin). In addition, the effects of these polyphenols on xanthine oxidase activity, spontaneous lipid peroxidation, and DNA cleavage were investigated. The bioflavonoids under examination showed a dose-dependent free-radical scavenging effect, a significant inhibition of xanthine oxidase activity, and an antilipoperoxidative capacity. In addition, they showed a protective effect on DNA cleavage.

Inhibition of neuronal nitric oxide synthase by N-phenacyl imidazoles

Nitric oxide (NO) mediates a series of physiological processes, including regulation of vascular tone, macrofage-mediated neurotoxicity, platelet aggregation, learning and long-term potentiation, and neuronal transmission. Although NO mediates several physiological functions, overproduction of NO can be detrimental and play multiple roles in several pathological diseases. Accordingly, more potent inhibitors, more selective for neuronal nitric oxide synthase (nNOS) than endothelial NOS (eNOS) or inducible NOS (iNOS), could be useful in the treatment of cerebral ischemia and other neurodegenerative diseases. We recently described the synthesis of a series of imidazole derivatives. Among them N-(4-nitrophenacyl) imidazole (A) and N-(4-nitrophenacyl)-2-methyl-imidazole (B) were considered selective nNOS inhibitors. In the present study the action mechanism of compounds A and B was analyzed. Spectral changes observed in the presence of compound A indicate that this inhibitor exerts its effect without interaction with heme iron. Moreover compounds A and B, inhibit nNOS "noncompetitively" versus arginine, but "competitively" versus BH(4).

Fibroblast growth factor-2 and transforming growth factor-beta1 immunostaining in rat brain after cerebral postischemic reperfusion

Several trophic factors are known to regulate the survival and growth of neurons in brain and peripheral tissues. Several findings suggest that basic fibroblast growth factor-2 (FGF-2) plays an important role in the "self-repair" responses that follow injuries such as trauma and brain ischemia and that FGF-2 contributes to the repair of damaged tissue. Transforming growth factor-beta (TGF-beta) is a potent growth-regulatory protein secreted by virtually all cells. In the present study, we used immunohistochemical techniques to investigate whether FGF-2 and TGF-beta1 participate in the healing of damaged tissue following partial brain ischemia. The profile of the observed immunoreactivities indicated that TGF-beta1 and FGF-2 release varies between the different cerebral areas subjected to ischemic insult. Moreover, the sectorial heterogeneity of immunocytochemical response suggests that, during postischemic reperfusion, neuronal recovery may be due not only to neuron-glia interaction but also to neurochemical conditions involving inhibitory interneurons.

Loss of p27Kip1 expression is a strong independent prognostic factor of reduced survival in N0 gastric carcinomas

BACKGROUND

p27KiP1 is a cyclin-dependent kinase inhibitor and is a potential tumor suppressor gene. Reduced expression of p27Kip1 is a powerful negative prognostic marker in primary lung, breast, colon, bladder, and prostate carcinomas. In the current study, the prognostic value of p27Kip1 in gastric cancer was evaluated and compared with other histopathologic parameters and p53 expression.

METHODS

p27Kip1 and p53 protein expression were determined by immunohistochemistry in 96 gastric carcinomas. The tumors were from a low incidence population and were selected for the absence of lymph node involvement.

RESULTS

Reduced expression of p27KiP1 (< or = 50% positive cells) and nuclear p53 accumulation (> 30% positive cells) were observed in 67 (69.8%) and 9 (9%) tumors, respectively, and were not related to either the pT category or tumor histology. Kaplan-Meier analyses revealed a significant impact on survival by p27Kip1 (P = 0.0001 by log rank test), p53 (P < 0.0001) expression, and the pT category (P < 0.0001). On multivariate analysis, reduced p27Kip1 protein expression was the strongest independent predictor of reduced survival (P = 0.005; relative risk = 3.348) out weighing the pT category (P = 0.010; relative risk = 2.257) and p53 overexpression (P = 0.016; relative risk = 2.618).

CONCLUSIONS

These data indicated that immunohistochemical detection of p27Kip1 could help to identify gastric carcinoma patients who are at high risk of death, even in the absence of lymph node involvement, and who might benefit from an adjuvant treatment following surgery.

Lipophilic methotrexate conjugates with antitumor activity

Lipophilic methotrexate (MTX)-lipoamino acid conjugates coupled with amide or ester linkages (1a-1r) were synthesised. The inhibitory activity of the conjugates was evaluated on bovine liver DHFR. The in vitro growth inhibitory effect against MTX-sensitive human lymphoblastoid CCRF-CEM cells and an MTX-resistant sub-line (CEM/MTX), which displays defective intracellular transport of MTX, was determined under short-term and continuous (120-h incubation) exposure conditions. The alpha, gamma, or alpha,gamma amide conjugates showed different activity in inhibiting the growth of parent cells. CEM/MTX cells were much less susceptible than CCRF-CEM cells to inhibition by alpha or alpha,gamma-substituted lipoamino acid conjugates, whereas both cell lines were almost equally sensitive to the MTX-gamma conjugates. Although less potent than MTX, they could partially circumvent the impaired transport system. These findings confirm that lipophilic MTX conjugates may be good lead compounds on the drug development for the treatment of some MTX-resistant tumors. Ester-type conjugates displayed an interesting activity against parent CCRF-CEM cells, although they were less potent against the transport-resistant sub-line. Stability studies on these molecules indicated that they are not degraded into MTX in the culture medium, thus suggesting that they are not able to over-cross cell resistance despite of their lipophilicity.

Nitric oxide synthetase activity in cerebral post-ischemic reperfusion and effects of L-N(G)-nitroarginine and 7-nitroindazole on the survival

Nitric Oxide (NO) mediates a series of physiological processes including regulation of vascular tone, macrophage-mediated cytotoxicity, platelet aggregation, learning and long-term potentiation, neuronal transmission. Although NO mediates several physiological functions, overproduction of NO can be detrimental and play multiple roles in the pathophysiology of focal cerebral ischemia. In the present study NOS activities were evaluated in cerebellum and cerebral cortex of ischemic and post-ischemic reperfused rats using an experimental model of partial cerebral ischemia; moreover, the effects of L-N(G)Nitroarginine (NA, nonselective NOS inhibitor) or 7-Nitroindazole (7-NI, selective neuronal NOS inhibitor) administration were assayed on percentage survival of ischemic rats. An increase of NOS activity in the cerebellum and in cerebral cortex of ischemic and post-ischemic reperfused rats was observed. NA administration failed to induce neuroprotective effects, by increasing percentage of mortality of treated ischemic rats with respect to control group. In contrast, the treatment with the selective neuronal NOS inhibitor, 7-NI, induced a significant neuroprotective effect.

Antioxidant systems in rat lens as a function of age: effect of chronic administration of vitamin E and ascorbate

Oxidative damage occurring in the lenses of patients with senile cataract may be due to partially reduced forms of oxygen. We assayed the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione reductase (GSH-Red), and glucose-6-phosphate dehydrogenase (G6PD) in rat lenses at different ages (1, 4, and 24 months), and also evaluated lens glutathione (GSH) levels and the effects of chronic administration of vitamin E and sodium ascorbate. We observed a significant age-related decrease in GSH-Px, GSH-Red and G6PD activities, but no age-related change in SOD activity. Chronic treatment with both vitamin E and sodium ascorbate failed to restore enzymatic activities to the levels of younger rats. An age-related reduction in GSH content was also observed; however, chronic administration of vitamin E, but not of sodium ascorbate, restored GSH levels to those of younger rats.

GFAP, S-100 and vimentin proteins in rat after cerebral post-ischemic reperfusion

In the present study astrocytes reactivity during cerebral post-ischemic reperfusion was evaluated immunocytochemically by using antibodies to vimentin, glial fibrillary acidic protein (GFAP) and S-100 protein. At the 7th day of post-ischemic reperfusion few GFAP-positive cells were observed in the hippocampus and cerebellum, the number of GFAP-positive cells increased slightly after 20 days of reperfusion. This poor GFAP-positivity may be due to the inhibition of GFAP polymerization by S-100; in fact, S-100 immuno-reactivity was already evident from the 7th day. Vimentin immuno-staining was evident both at the 7th and 20th day of reperfusion in microglial cells and in oligodendrocytes, suggesting that these cells are involved in the recovery of neurons following brain injury.

Effects of glutathione depletors on post-ischemic reperfusion in rat brain

The present paper reports the effects of GSH depletion (diethylmaleate induced) on partial cerebral ischemia and reperfusion for 7 and 20 days. Our results confirm that there is a paradoxical protective effect of the GSH-depletor and suggest an improved neuronal trophism induced by diethylmaleate treatment.

MAP2, synaptophysin immunostaining in rat brain and behavioral modifications after cerebral postischemic reperfusion

Plasticity in the central nervous system after cerebral ischemia is a controversial issue; focal cerebral ischemia produces an area of infarction that is surrounded by neurons that may respond to nearby damage by creating new synapses. In the present study the expression of the postsynaptic microtubule-associated protein 2 (MAP2) and the presynaptic marker protein, synaptophysin, was investigated by immunocytochemical techniques in the CA1 sector of hippocampus and in cerebellum of rats made ischemic by bilateral clamping of common carotid arteries and reperfused for 7 and 30 days. In addition, ischemia-induced behavioral alterations were also evaluated after 7 and 30 days of reperfusion. The present study demonstrates a decreased postsynaptic MAP2 immunoreactivity, representative of neuronal loss, particularly in CA1 sector of hippocampus and in cerebellum of ischemic rats reperfused for 7 days. After 30 days of reperfusion, MAP2 immunostaining was similar to control. In the same brain sections an increased presynaptic synaptophysin immunoreactivity has been observed only after 30 days of reperfusion. These data suggest compensatory regenerative changes associated with synaptic remodelling and are supported by behavioral recovery observed under the same experimental conditions.

Ornithine decarboxylase activity in cerebral post-ischemic reperfusion damage: effect of methionine sulfoximine

Excessive activation of glutamate receptors via the N-methyl-D-aspartate (NMDA) subtype appears to play a role in the sequence of cellular events which lead to irreversible ischemic damage to neurons. Furthermore, NMDA receptor activation induces a stimulation of ornithine decarboxylase (ODC), the rate-limiting enzyme for polyamine (PA) biosynthesis. In order to better understand the role of PA we have measured ODC activity and the effect of methionine sulfoximine (MSO), a molecule able to stimulate ODC, on a model of transient cerebral ischemia. There was a significant increase in ODC activity in the rat cerebral cortex during post-ischemic reperfusion. The treatment with MSO induced a significant decrease in cerebral glutamine synthetase activity accompanied by a marked increase in ODC activity. In MSO-pretreated rats there was a significant decrease in the survival rate when compared to untreated ischemic rats.

Neuronal lesions and behavioral modifications in rat following cerebral ischemia and reperfusion

Neurons of the mammalian CNS differ in their vulnerability to various disease processes and other insults, particularly in their response to total anoxia/ischemia. In this study we have tested the histological and behavioral modifications induced by experimental conditions of partial cerebral ischemia in the rats. The specific morphological and histological alterations, observed in our experimental conditions of reversible partial cerebral ischemia, confirm the selective vulnerability of certain neuronal populations to ischemic injury and are also evidenced by behavioral modifications which may mirror the functional impairment observed in humans after a transitory ischemic attack.

Synthesis and preliminary in vitro screening of lipophilic alpha, gamma-bis(amides) as potential prodrugs of methotrexate

As part of a program aimed at studying the feasibility of amide derivatives of methotrexate (MTX) as lipophilic prodrugs, with the aims of increasing passive cellular uptake and obtaining prolonged-release agents, we describe the synthesis of five long-chain alkyl bis(amides) of MTX, from decyl- to octadecylamide, by direct transamidation to the MTX diethyl ester. Compounds were subjected to a preliminary biological screening, to assess their inhibitory activity against bovine liver dihydrofolate reductase (DHFR) and in vitro antitumor activity against human leukemia CCRF-CEM cells. As a general trend, an increase in lipophilicity led to a linear reduction of enzyme inhibition; however, the bis(decyl)amide derivative showed a good intrinsic affinity for DHFR (IC50 6.41 nM), comparable to that of MTX diethyl ester and close to that of MTX (IC50 2.90 nM). In the antitumor assay, lower homologues (C10-C14) displayed an interesting activity profile, suggesting the desirability of additional studies with these and similar compounds.

Detection of anti-HCV IgM antibodies in patients with chronic hepatitis C treated with interferon

OBJECTIVE

To assess the role of IgM antibodies to hepatitis C virus core protein (anti-HCV IgM) as a marker of chronic HCV infection and as a predictor of successful interferon (IFN) treatment.

DESIGN

Anti-HCV IgM levels were evaluated at baseline, during IFN therapy and during a follow-up period.

METHODS

Anti-HCV IgM levels were evaluated in 62 patients (47 men and 15 women, aged 25-65 years) with biopsy-proven chronic active hepatitis C. Fifty-one of the patients received alpha-IFN 3 MU three times a week for 6 months and 11 received the same therapy for 12 months. Twenty patients showed a long-term response; fourteen responded but subsequently suffered a relapse; twenty-eight did not respond to the treatment. Follow-up in all patients lasted for at least 6 (mean +/- SD 9.8 +/- 5.4, range 6-29) months after the end of the therapy.

RESULTS

Anti-HCV IgM were detected in 35 patients (56.4%) at baseline; no significant differences were observed between the three groups studied. Almost all members of the groups showing a relapse or no response remained positive at the end of therapy and follow-up. In contrast, we observed a progressive disappearance of anti-HCV IgM in patients responsive to interferon therapy over the long term.

CONCLUSION

The loss of anti-HCV IgM positivity in patients positive at baseline can predict the long-term response to IFN therapy.

Liposomes as in-vivo carriers for citicoline: effects on rat cerebral post-ischaemic reperfusion

Citicoline is a therapeutic agent widely used in the treatment of brain injury, for example in cerebrovascular disease or traumatic accidents. Unfortunately, the strong polar nature of this drug prevents it crossing the blood-brain barrier. In this paper, the possibility of efficiently trapping citicoline in liposomes to improve its therapeutic effects is reported. The citicoline-encapsulation efficiency, drug leakage and size analysis of various liposome systems were studied. The real therapeutic effectiveness of these citicoline liposome formulations was evaluated by biological assay. The effects of free and liposome encapsulated citicoline on survival rate of ischaemic reperfused male Wistar rats (80-100 g) were investigated. Of the phospholipid mixtures used in citicoline liposome formulation the best in terms of delivery and therapeutic effects was 1,2-dipalmitoyl-sn-glycero-phosphocholine: dipalmitoyl-DL-alpha-phosphatidyl-L-serine:cholesterol (7:4:7 molar ratio). This phospholipid mixture was also assayed for brain conjugated diene levels in rats, since this parameter is an index of lipid peroxidation in rat cerebral cortex during post-ischaemic reperfusion. A citicoline-loaded phospholipid mixture has produced an increase in rat survival rate of about 24% and a reduction in diene levels of 60%, compared to the free drug.

Glutathione-S-transferase and NADPH cytochrome P450 reductase activities in rat placenta during pregnancy

Mammalian gestation depends on the continuous synthesis of steroid hormones such as progesterone, estrogens and gonadotrophic hormones. Placental microsomes are involved in the metabolism of steroid hormones via NADPH cytochrome P450 reductase; this last enzyme is involved in the generation of O2 and H2O2. These partially reduced oxygen forms are scavenged by endogenous antioxidants such as GSH and the related GSH-S-transferase enzyme. The present study has the aim of evaluating whether placental hormonal modification occurring during gestation influences NADPH cytochrome P450 reductase and GSH-S-transferase activities. The results demonstrate a gradual increase of both enzymatic activities which suggests a defense ability of the placenta.

Heat shock proteins following rat cerebral ischemic/reperfusion episode: effect of ketamine

This paper reports the influence of ketamine on HSP70 expression, during an ischemic/reperfusion episode, in rat cerebral cortex and hippocampus. The results indicate that ketamine, injected 1h before the surgical treatment, increases HSP70 cellular concentration in both ischemic and sham-operated animals. The HSP70 levels, after the transient ischemic episode, are higher in ketamine treated than in urethane-treated animals respect to the control levels. After reperfusion an increase of HSP70 levels is observed; this induction is maintained for at least 22h, irrespective of the anaesthetic drug treatment. Comparing the cerebral areas examined, the hippocampus exhibits higher protein levels than those of the cerebral cortex.

Free radical scavenger depletion in post-ischemic reperfusion brain damage

In the present study the influence of pretreatment with various GSH depletors such as buthionine sulfoximine (BSO) and diethylmaleate (DEM) was investigated in rats following cerebral post-ischemic reperfusion. Moreover, the effect of diethyldithiocarbamic acid (DDC), inhibitor of endogenous Cu,Zn-SOD, was evaluated. A significant depletion (40% of control value) of GSH levels was observed 24 h after DEM administration; after 48 h the value reached control levels. BSO showed maximal GSH depletion (59%) 24 h after administration and it was constant for almost 48 h. DDC administration caused a marked decrease (60%) of Cu,Zn-SOD activity 4 h after the injection and induced a marked decrease in percentage of survival with respect to control (untreated, ischemic) rats, when administered 4 h before ischemia. BSO and DEM prolonged the survival time of animals when administered 24 h before ischemia. This last paradoxical effect is unclear at present, but it might be due to an influence on glutamate cascade.

Effect of acetyl-L-carnitine on lipid peroxidation and xanthine oxidase activity in rat skeletal muscle

It has been reported that acetyl-L-carnitine (AcCn) can reduce the degenerative processes in the central nervous system of rats, modify the fluidity of membranes and decrease the accumulation of lipofuscins in neurones. In light of these considerations we have assayed the in vitro effect of acetyl-L-carnitine on spontaneous and induced lipoperoxidation in rat skeletal muscle; in addition, the effect of AcCn on XD/XO ratio was evaluated. The presence of AcCn (10-40 mM) in incubation medium significantly reduced MDA and conjugated diene formation in rat skeletal muscle; moreover, a significant decrease in induced MDA levels was observed when microsomal preparation where incubated in the presence of 10-40 mM AcCn. Since a significant reduction of XO activity was detected in the presence of 10-80 mM AcCn, the reduced lipid peroxidation by AcCn seems to be due to an inhibition of XO activity.

Is Early Gastric Cancer, Diffuse Type, a Forerunner of Advanced Gastric Cancer?

Aims and Background

Gastric cancer (GC) represents one of the most Important causes of death by malignancy world wilde. Our retrospective study was carried out on surgical stomach specimens obtained from a series of 552 consecutive cases of GC observed in the Departments of Surgical Pathology of the Public Hospitals of L'Aquila and Atri which cover the 17 % of the entire population of the Italian Region Abruzzo. The aim of the study was to compare the anatomo-clinical characteristics of early GC (EGC) and advanced GC (AGC).

Methods

The diagnosis was achieved by the criteria of the Lauren's histopathological classification (intestinal and diffuse types). Our study also stratified the cases by sex, age, lymph node metastases and associated lesions such as chronic atrophic gastritis, intestinal metaplasia and dysplasia.

Results

On an average, patients affected by EGC were 8.1 years younger than those with AGC. This age gap could support the hypothesis that early lesions represent the first stage of AGC. However, when patients were subdivided according to Lauren's classification, the mean age of patients with EGC, diffuse type, was 12.2 years less than that of AGC patients of the corresponding histological type. Furthermore, the subset of patients with EGC, diffuse type, and lymph node metastases was 17.8 years younger than patients affected by AGC diffuse type, with lymph node metastases.

Conclusions

The present study offers an original survey on GC in a defined Italian population. As far as the intestinal histotype is concerned, the slight age difference between EGC and AGC suggests that these tumors are different steps of the same process. On the contrary, the age distribution suggests that EGC, diffuse type, has a different biological behaviour.

Transglutaminase activity in primary and subcultured rat astroglial cells

Transglutaminases, calcium-dependent thiol enzymes, may be involved in cellular growth control and differentiation, having an intracellular regulatory role in some post-translational modifications found in various classes of proteins. In order to elucidate the involvement of this class of enzymes in cellular differentiation processes, we have assayed transglutaminase activity in primary and subcultured rat glial cells. Reduced activity was found from 3rd to 5th passage. In the 5th passage the activity was some 50% of that found in the primary cultures and was not restored by addition of 10 microM retinoic acid. The decrease of TGase activity, observed during serial passages, could represent an early metabolic alteration related to cell dedifferentiation and loss of growth control. In fact, the subcultured cells may have undergone a "disarranged" state, as confirmed by a decrease in GFAP-stained cells and glutamine synthetase activity, respectively, immunocytochemical and biochemical markers of astroglial cells.

Impaired antioxidant defense mechanisms in two children with hemolytic-uremic syndrome

In the present study we have assayed antioxidant enzymatic activities of SOD, CAT, GSH-Px, GSH-Red, and G6PD in erythrocytes from two children with hemolytic-uremic syndrome (HUS) during the acute phase of the disease and after their recovery; in addition, we have tested the percentage of hemolysis after 24-h incubation in PBS containing glucose (1 g/1000 mL) or in the presence of their own plasma. Endogenous plasmatic MDA levels were also evaluated as lipid peroxidation marker. A significant decrease in SOD activity was found in erythrocytes from HUS patients, and the addition of their own plasma further decreased SOD activity. Elevated percentage of hemolysis was found in HUS patients when RBCs were incubated in their own plasma; this last effect was less evident in PBS + glucose.

Lipid peroxidation and antioxidant enzymatic systems in rat retina as a function of age

In the present study, we have assayed the enzymatic activity of Cu,Zn-SOD, Mn-SOD, GSH-Px, GSH-Red, Cat, and G6PD in rat retina as a function of age. Conjugated diene levels and MDA formation were also determined. The conjugated diene levels in rat retina were found to increase significantly with age, accompanied by a marked decrease in GSH-Px and Cat activities. No age-related change in MDA levels and in GSH-Red and G6PD activity was found, whereas a significant increase in SOD activity was observed between 1 and 4 months. Decreased GSH-Px and Cat activity is related to increased lipid peroxidation with age.

Lipid peroxidation in rat cerebral cortex during post-ischemic reperfusion: effect of exogenous antioxidants and Ca(++)-antagonist drugs

Although the role of oxidant-antioxidant metabolism in total ischemia and reperfusion in the central nervous system and cardiac myocardium have been well studied, less is known about the consequences of partial ischemic episodes. Here we show that reperfusion contributes to free radical formation as judged by conjugated diene formation. Also, antioxidants and Ca++ antagonists were able to reduce free radical formation. These results would suggest that free radical generation following ischemia and reperfusion may result from more than one injury process in cerebral cortex.

Antioxidant enzymatic systems and oxidative stress in erythrocytes with G6PD deficiency: effect of deferoxamine

In the present study we have assayed the effect of divicine in G6PD-deficient red blood cells in the presence of deferoxamine (iron-chelating drug) and NaN3 (inhibitor of catalase). The effect of divicine has been compared to oxidative stress by H2O2; haemolysis is regarded as an index of cellular toxicity. In addition, we have tested antioxidant enzymatic systems. No significant change in antioxidant enzymatic systems was found in RBCs from subjects with G6PD deficiency when compared to the control group, either in oxidative haemolysis by divicine or by H2O2; a significant decrease in oxidative haemolysis by H2O2 was observed in the presence of deferoxamine, whereas no change was found in oxidative haemolysis by divicine. The replacement of incubation medium by homologous plasma or the supplementation with bovine serum albumin resulted in a marked decrease of percentage of haemolysis by divicine.

Neurotransmitter amino acid levels in rat thalamus and cerebral cortex after cerebellectomy

Glutamate, aspartate, GABA, glycine and taurine levels have been measured in rat thalamus and in cerebral cortex at different time intervals (3rd, 7th, 15th, 30th day) after cerebellectomy. A decrease in glutamate, aspartate and GABA was detected at the 7th day after cerebellectomy in the thalamus and at the 15th day in the cerebral cortex; at the 30th day after cerebellectomy the levels of these amino acids in the thalamus and in the cerebral cortex were observed to have recovered to control values. No statistically significant difference in glycine and taurine levels in the thalamus and in the cerebral cortex after cerebellectomy could be seen. These results show that the functional recovery process after cerebellar injury is associated with a complex modification of amino acid levels in thalamus and in cerebral cortex.