The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine induces apoptosis in mouse nigrostriatal glia. Relevance to nigral neuronal death and striatal neurochemical changes.

Swiss mice were given 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), 25 mg/kg/day, for 5 consecutive days and killed at different days after MPTP discontinuance. Decreases in striatal tyrosine hydroxylase activity and levels of dopamine and its metabolites were observed 1 day after MPTP discontinuance. Ascorbic acid and glutamate levels had increased, dehydroascorbic acid and GSH decreased, whereas catabolites of high-energy phosphates (inosine, hypoxanthine, xanthine, and uric acid) were unchanged. In addition, gliosis was observed in both striatum and substantia nigra compacta (SNc). Sections of SNc showed some terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling (TUNEL)-positive cells. Neurochemical parameters of dopaminergic activity showed a trend toward recovery 3 days after MPTP discontinuance. At this time point, TUNEL-positive cells were detected in SNc; some of them showed nuclei with neuronal morphology. A late (days 6-11) increase in striatal dopamine oxidative metabolism, ascorbic acid oxidative status, and catabolites of high-energy phosphates were observed concomitant with nigral neuron and nigrostriatal glial cell apoptotic death, as revealed by TUNEL, acridine orange, and Hoechst staining, and transmission electron microscopy. These data suggest that MPTP-induced activation/apoptotic death of glial cells plays a key role in the sequential linkage of neurochemical and cellular events leading to dopaminergic nigral neuron apoptotic death

Acute Delta Hepatitis in Italy spanning three decades (1991–2019): Evidence for the effectiveness of the hepatitis B vaccination campaign

Updated incidence data of acute Delta virus hepatitis (HDV) are lacking worldwide. Our aim was to evaluate incidence of and risk factors for acute HDV in Italy after the introduction of the compulsory vaccination against hepatitis B virus (HBV) in 1991. Data were obtained from the National Surveillance System of acute viral hepatitis (SEIEVA). Independent predictors of HDV were assessed by logistic-regression analysis. The incidence of acute HDV per 1-million population declined from 3.2 cases in 1987 to 0.04 in 2019, parallel to that of acute HBV per 100,000 from 10.0 to 0.39 cases during the same period. The median age of cases increased from 27 years in the decade 1991-1999 to 44 years in the decade 2010-2019 (p < .001). Over the same period, the male/female ratio decreased from 3.8 to 2.1, the proportion of coinfections increased from 55% to 75% (p = .003) and that of HBsAg positive acute hepatitis tested for by IgM anti-HDV linearly decreased from 50.1% to 34.1% (p < .001). People born abroad accounted for 24.6% of cases in 2004-2010 and 32.1% in 2011-2019. In the period 2010-2019, risky sexual behaviour (O.R. 4.2; 95%CI: 1.4-12.8) was the sole independent predictor of acute HDV; conversely intravenous drug use was no longer associated (O.R. 1.25; 95%CI: 0.15-10.22) with this. In conclusion, HBV vaccination was an effective measure to control acute HDV. Intravenous drug use is no longer an efficient mode of HDV spread. Testing for IgM-anti HDV is a grey area requiring alert. Acute HDV in foreigners should be monitored in the years to come

Manganese and 1-methyl-4-(2′-ethylphenyl)-1,2,3,6-tetrahydropyridine induce apoptosis in PC12 cells

Oxidative stress is thought to play a key role both in the neurotoxin MPTP- and manganese (Mn)-induced neurotoxicity and in apoptotic cell death. In the present study, we report that Mn and the MPTP analogue 1-methyl-4-(2′-ethylphenyl)-1,2,3,6-tetrahydropyridine (2′Et-MPTP), which is metabolized by MAO-A to 1-methyl-4-(2′-ethylphenyl)-pyridinium ion (at concentrations of 0.5 and 1.0 mM), induced apoptosis in PC12 cells. Apoptosis was tested by terminal deoxynucleotidyl transferase-mediated 2′-deoxyuridine-5′-triphosphate nick end labelling (TUNEL) technique, flow cytometry and fluorescence microscopy. Both Mn and 2′Et-MPTP induced also a time-dependent decrease in cell viability, as determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Only Mn-induced apoptosis and decrease in cell viability were inhibited by the antioxidant ascorbic acid. We conclude that apoptosis may be an important mechanism of cell death in MPTP- and Mn-induced parkinsonism. However, an oxidative stress mechanism may be recognized only in the Mn-induced apoptosis

Synthesis, molecular docking and cholinesterase inhibitory activity of hydroxylated 2-phenylbenzofuran derivatives

We have designed, synthesized and evaluated a series of hydroxylated 2-phenylbenzofuran derivatives as potential cholinesterase inhibitors. Starting from a series of 2-phenylbenzofurans previously published, in this paper we present a complete synthesis and the influence on the activity of one or two hydroxyl groups located in meta or in meta and para positions respectively of the 2-phenyl ring and highlight the importance of position of hydroxyl groups. Moreover, simultaneous introduction of halogen at position 7 of the benzofuran scaffold resulted in an improved inhibitory activity against the enzyme. To further provide molecular insight and to identify the most probable ligand-binding site of the protein, docking studies were performed for the top-ranked compounds. Docking results revealed conserved ligand-binding residues and supported the role of catalytic site residues in enzyme inhibition

Role of oxidative stress in the manganese and 1-methyl-4-(2′-ethylphenyl)-1,2,3,6-tetrahydropyridine-induced apoptosis in PC12 cells

Oxidative stress is thought to play a key role in the apoptotic death of several cellular systems, including neurons. Oxidative stress is proposed also as a mechanism of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)- and manganese (Mn)-induced neuronal death. We have recently shown that Mn and the MPTP analogue 1-methyl-4-(2′-ethylphenyl)-1,2,3,6-tetrahydropyridine (2′Et-MPTP), which is metabolized by MAO-A to 1-methyl-4-(2′-ethylphenyl)-pyridinium ion, induce apoptosis in PC12 cells. In the present study, we evaluated the effects of deprenyl and the antioxidant drugs N-acetylcysteine (NAC) and ascorbic acid (AA) on Mn- and 2′Et-MPTP-induced apoptosis in PC12 cells. Apoptosis was tested by terminal deoxynucleotidyl transferase-mediated 2′-deoxy-uridine-5′-triphosphate nick end labelling (TUNEL) technique, flow cytometry and fluorescence microscopy. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Mn-induced apoptosis and decrease in cell viability was inhibited by the antioxidants NAC and AA. Deprenyl failed to inhibit the above Mn effects. Neither NAC, AA nor deprenyl were able to inhibit both 2′Et-MPTP-induced apoptosis and decrease in cell viability. These results confirm that apoptosis may be an important mechanism of cell death in MPTP- and Mn-induced parkinsonism. However, an oxidative stress mechanism may be recognized, at least in vitro, only in the Mn-induced apoptosis

Long-Term Survival and Intracellular Replication of Mycoplasma hominis in Trichomonas vaginalis Cells: Potential Role of the Protozoon in Transmitting Bacterial Infection

The existence of a symbiotic relationship between Trichomonas vaginalis and Mycoplasma hominis, which is the first reported example of symbiosis between two obligate human pathogens, has been recently reported by our research group. In this work, we examined the cellular location of M. hominis in respect to T. vaginalis. By using gentamicin protection assays, double immunofluorescence, and confocal microscopy, we obtained strong evidence that M. hominis is located within protozoan cells. 5-Bromodeoxyuridine incorporation assays showed that intracellularly located mycoplasmas actively synthesize DNA. Our results demonstrate that M. hominis has the capability of entering trichomonad cells and of replicating inside the protozoon. These findings suggest that symbiosis might provide the bacteria, during human infection, with the capability to resist to environmental stresses, such as host defense mechanisms and pharmacological therapies

On the Mechanism of Levosimendan-Induced Dopamine Release in the Striatum of Freely Moving Rats

The Ca2+ sensitizer levosimendan (LEV) improves myocardial contractility by enhancing the sensitivity of the contractile apparatus to Ca2+. In addition, LEV promotes Ca2+ entry through L-type channels in human cardiac myocytes. In this study, which was performed using microdialysis, infusion of LEV at 0.25 μM for 160 min increased dopamine (DA) concentrations (up to fivefold baseline) in dialysates from the striatum of freely moving rats. Ca2+ omission from the perfusion fluid abolished baseline DA release and greatly decreased LEV-induced DA release. Reintroduction of Ca2+ in the perfusion fluid restored LEV-induced DA release. Chelation of intracellular Ca2+ by co-infusing 1,2-bis (o-amino-phenoxy)ethane-N,N,N′,N′-tetraacetic acid tetra (acetoxymethyl) ester (BAPTA-AM, 0.2 mM) did not affect basal DA release and scarcely affected LEV-induced increases in dialysate DA. In addition, co-infusion of the L-type (Cav 1.1 – 1.3) voltage-sensitive Ca2+-channel inhibitor nifedipine failed to inhibit LEV-induced increases in dialysate DA, which, in contrast, was inhibited by co-infusion of the N-type (Cav 2.2) voltage-sensitive Ca2+-channel inhibitor ω-conotoxin GVIA. We conclude that LEV promotes striatal extracellular Ca2+ entry through N-type Ca2+ channels with a consequent increase in DA release. Keywords:: levosimendan, microdialysis, striatal dopamine, calcium entr

Long-term survival and intracellular replication of <i>Mycoplasma hominis</i> in <i>Trichomonas vaginalis</i> cells: potential role of the protozoon in transmitting bacterial infection

The existence of a symbiotic relationship between Trichomonas vaginalis and Mycoplasma hominis, which is the first reported example of symbiosis between two obligate human pathogens, has been recently reported by our research group. In this work, we examined the cellular location of M. hominis in respect to T. vaginalis. By using gentamicin protection assays, double immunofluorescence, and confocal microscopy, we obtained strong evidence that M. hominis is located within protozoan cells. 5-Bromodeoxyuridine incorporation assays showed that intracellularly located mycoplasmas actively synthesize DNA. Our results demonstrate that M. hominis has the capability of entering trichomonad cells and of replicating inside the protozoon. These findings suggest that symbiosis might provide the bacteria, during human infection, with the capability to resist to environmental stresses, such as host defense mechanisms and pharmacological therapies

A Study on the role of nitric oxide and iron in 3-morpholino-sydnonimine-induced increases in dopamine release in the striatum of freely moving rats

We showed previously that interaction between NO and iron (II), both released following the decomposition of sodium nitroprusside (SNP), accounted for the late SNP-induced dopamine (DA) increase in dialysates from the striatum of freely moving rats; in addition, we showed that co-infusion of iron (II) with the NO-donor S-nitroso-N-acetylpenicillamine mimicked SNP effects on striatal DA release. In the present study, intrastriatal co-infusion of iron (II) (given as FeSO4, 1 mM for 40 min) with the NO-donor and potential peroxynitrite generator 3-morpholinosydnonimine (SIN-1) (0.2, 0.5, 1.0 or 5.0 mM for 180 min), potentiated the SIN-1-induced increase in DA concentration in dialysates from the striatum of freely moving rats. Neither alone nor associated with iron (II) did SIN-1 induce changes in dialysate ascorbic acid or uric acid concentrations. Neither co-infusion of a superoxide dismutase mimetic nor uric acid affected SIN-1-induced increases in dialysate DA concentration. Infusion of the iron chelator deferoxamine (0.2 mM for 180 min) decreased dialysate DA and attenuated SIN-1-induced increases in dialysate DA concentrations. These results suggest that iron plays a key role in SIN-1-induced release of striatal DA and do not support any role for either peroxynitrite or superoxide anion in SIN-1-induced release of striatal DA

Glutathione deficiency potentiates manganese-induced increases in compounds associated with high-energy phosphate degradation in discrete brain areas of young and aged rats

Aging is a factor known to increase neuronal vulnerability to oxidative stress, which is widely accepted as a mechanism of manganese-induced neuronal damage. We previously showed that subchronic exposure to manganese induced greater energy impairment (as revealed by increases in hypoxanthine, xanthine and uric acid levels) in the striatum and brainstem of aged rats vs young rats. This study shows that inhibition of glutathione (GSH) synthesis, by means of buthionine (SR) sulfoximine, decreased GSH levels and increased the ascorbic acid oxidation status in the striatum and limbic forebrain of both young and aged rats. In addition, inhibition of GSH synthesis greatly potentiated the manganese-induced increase in inosine, hypoxanthine, xanthine and uric acid levels in both regions of aged rats; moreover, inhibition of GSH synthesis significantly increased inosine, hypoxanthine, xanthine and uric acid levels in both regions of young rats, compared with the manganese-treated group. These results suggest that an impairment in the neuronal antioxidant system renders young rats susceptible to manganese-induced energetic impairment, and further support the hypothesis that an impairment in this system plays a permissive role in the increase of neuronal vulnerability that occurs with aging