Efficacy of lisinopril in migraine prophylaxis ? an open label study

The ACE-inhibitor lisinopril has previously been shown to be effective in migraine prophylaxis at a daily dose of 20 mg. To test the effect of a low dose of lisinopril (5 mg daily) in migraine prevention, we performed an open label study in 21 migraineurs. The primary outcome measure was frequency of migraine attacks. Secondary efficacy measures were migraine hours, intake of acute migraine drugs, pain intensity and responder rate. Compared with baseline conditions, the attack frequency of migraine attacks was significantly reduced (P < 0.0005). The number of acute migraine drugs dropped significantly (P = 0.002). Three patients dropped out because of intolerable cough. Our study suggests that even low doses of lisinopril may be effective in migraine treatment. However, its use may be limited by intolerable side-effects.

Neurotoxicity mechanisms of thioether ecstasy metabolites

3,4-Methylenedioxymethamphetamine (MDMA or "ecstasy"), is a widely abused, psychoactive recreational drug that is known to induce neurotoxic effects. Human and rat hepatic metabolism of MDMA involves N-demethylation to 3,4-methylenedioxyamphetamine (MDA), which is also a drug of abuse. MDMA and MDA are O-demethylenated to N-methyl-alpha-methyldopamine (N-Me-alpha-MeDA) and alpha-methyldopamine (alpha-MeDA), respectively, which are both catechols that can undergo oxidation to the corresponding ortho-quinones. Ortho-quinones may be conjugated with glutathione (GSH) to form glutathionyl adducts, which can be transported into the brain and metabolized to the correspondent N-acetylcysteine (NAC) adducts. In this study we evaluated the neurotoxicity of nine MDMA metabolites, obtained by synthesis: N-Me-alpha-MeDA, alpha-MeDA and their correspondent GSH and NAC adducts. The studies were conducted in rat cortical neuronal cultures, for a 6 h of exposure period, under normal (36.5 degrees C) and hyperthermic (40 degrees C) conditions. Our findings show that thioether MDMA metabolites are strong neurotoxins, significantly more than their correspondent parent catechols. On the other hand, N-Me-alpha-MeDA and alpha-MeDA are more neurotoxic than MDMA. GSH and NAC conjugates of N-Me-alpha-MeDA and alpha-MeDA induced a concentration dependent delayed neuronal death, accompanied by activation of caspase 3, which occurred earlier in hyperthermic conditions. Furthermore, thioether MDMA metabolites time-dependently increased the production of reactive species, concentration-dependently depleted intracellular GSH and increased protein bound quinones. Finally, thioether MDMA metabolites induced neuronal death and oxidative stress was prevented by NAC, an antioxidant and GSH precursor. This study provides new insights into the neurotoxicity mechanisms of thioether MDMA metabolites and highlights their importance in "ecstasy" neurotoxicity.

Ecstasy-induced cell death in cortical neuronal cultures is serotonin 2A-receptor-dependent and potentiated under hyperthermia

Studies on 3,4-methylenedioxymethamphetamine ("ecstasy")-induced neurotoxicity mainly focus on damage of serotonergic terminals. Less attention has been given to neuronal cell death produced by 3,4-methylenedioxymethamphetamine and other amphetamines in areas including the cortex, striatum and thalamus. In the present study we investigated 3,4-methylenedioxymethamphetamine-induced neurotoxicity in neuronal serum free cultures from rat cortex. Since 3,4-methylenedioxymethamphetamine intake induces hyperthermia in both animals and humans, the experiments were performed under normal (36.5 degrees C) and hyperthermic conditions (40 degrees C). Our findings showed a dose-, time- and temperature-dependent apoptotic cell death induced by 3,4-methylenedioxymethamphetamine in cortical neurons. 3,4-Methylenedioxymethamphetamine-induced damage was potentiated under hyperthermia. The neurotoxicity was reduced by the serotonin 2A-receptor antagonists, ketanserin and (2R,4R)-5-[2-[2-[2-(3-methoxyphenyl)ethyl]phenoxy]ethyl]-1-methyl-3-pyrrolidinol hydrochloride, in both normothermic and hyperthermic conditions. (+/-)-2,5-Dimethoxy-4-iodoamphetamine hydrochloride, a model agonist for the serotonin 2A-receptor, also induced a dose- and time-dependent apoptotic cell death. Again, protection was provided by ketanserin and (2R,4R)-5-[2-[2-[2-(3-methoxyphenyl)ethyl]phenoxy]ethyl]-1-methyl-3-pyrrolidinol hydrochloride against (+/-)-2,5-dimethoxy-4-iodoamphetamine hydrochloride-induced neurotoxicity, thereby indicating that the 3,4-methylenedioxymethamphetamine stimulation of the serotonin 2A-receptor leads to neurotoxicity. This study provides for the first time evidence that direct 3,4-methylenedioxymethamphetamine serotonin 2A-receptor stimulation leads to neuronal cortical death. alpha-Phenyl-N-tert-butyl nitrone a free radical scavenger and the nitric oxide synthase inhibitor Nomega-nitro-L-arginine as well as the NMDA-receptor antagonist MK-801 provided protection under normothermia and hyperthermia, thereby suggesting the participation of free radicals in 3,4-methylenedioxymethamphetamine-induced cell death. Since 3,4-methylenedioxymethamphetamine serotonin 2A-receptor agonistic properties lead to neuronal death, clinically available atypical antipsychotic drugs with serotonin 2A-antagonistic properties could be a valuable therapeutic tool against 3,4-methylenedioxymethamphetamine-induced neurodegeneration.

Downregulation of c-Jun expression and cell cycle regulatory molecules in acute myeloid leukemia cells upon CD44 ligation

In the present study, we investigated the mechanism of CD44 ligation with the anti-CD44 monoclonal antibody A3D8 to inhibit the proliferation of human acute myeloid leukemia (AML) cells. The effects of A3D8 on myeloid cells were associated with specific disruption of cell cycle events and induction of G0/G1 arrest. Induction of G0/G1 arrest was accompanied by an increase in the expression of p21, attenuation of pRb phosphorylation and associated with decreased Cdk2 and Cdk4 kinase activities. Since c-Jun is an important regulator of proliferation and cell cycle progression, we analysed its role in A3D8-mediated growth arrest. We observed that A3D8 treatment of AML patient blasts and HL60/U937 cells led to the downregulation of c-Jun expression at mRNA and protein level. Transient transfection studies showed the inhibition of c-jun promoter activity by A3D8, involving both AP-1 sites. Furthermore, A3D8 treatment caused a decrease in JNK protein expression and a decrease in the level of phosphorylated c-Jun. Ectopic overexpression of c-Jun in HL60 cells was able to induce proliferation and prevent the antiproliferative effects of A3D8. In summary, these data identify an important functional role of c-Jun in the induction of cell cycle arrest and proliferation arrest of myeloid leukemia cells because of the ligation of the cell surface adhesion receptor CD44 by anti-CD44 antibody. Moreover, targeting of G1 regulatory proteins and the resulting induction of G1 arrest by A3D8 may provide new insights into antiproliferative and differentiation therapy of AML.

Effects of cerebral ischemia in mice lacking DNA methyltransferase 1 in post-mitotic neurons

DNA methylation is important for controlling gene expression and is catalyzed by DNA methyltransferase (Dnmt1) an enzyme abundant in brain. We recently demonstrated that mice expressing reduced levels of Dnmt1 are protected from cerebral ischemia. Here, we used the cre/loxP system to produce conditional mutants that lack Dnmt 1 in postmitotic neurons of the postnatal brain. We demonstrate that animals heterozygous for the conditional allele (Dnmt11lox/+) have significantly smaller infarcts following 1 h middle cerebral artery occlusion/reperfusion compared to their wildtype litters. Surprisingly, mice with a deletion of Dnmt1 in post-mitotic neurons (Dnmt11lox/c) were not protected. In conclusion, we demonstrate that reduced levels of Dnmt1, but not its absence, in post-mitotic neurons protect from ischemic brain injury.

[Ischemia tolerance; model for research, hope for clinical practice?]

A brief episode of ischemia renders the brain resistant against subsequent, longer ischemic events. This ischemic tolerance has been shown in numerous experimental models of cerebral ischemia. After global cerebral ischemia, ischemic tolerance may protect up to 90% of hippocampal CA1 neurons. In focal ischemia, this phenomenon reduces infarct volume by 20-60%. However, the basic molecular mechanisms of ischemic tolerance are largely unknown. During the induction phase, N-methyl-d-aspartate (NMDA) and adenosine receptors and, possibly, oxygen free radicals and conservation of energy metabolism are required. Protein kinases, transcription factors, and immediate early genes appear to transduce the signal into a tolerant response. Ischemic tolerance can be observed in different phases. The early phase lasts for several hours after the preconditioning stimulus and adenosine receptors and ATP-dependent potassium channels play a role similar to that in cardiac ischemic tolerance. The delayed protection, retained for a maximum of 2-4 days, currently is best explained by genetic remodeling with expression or repression of multiple genes. Several candidates have been identified to date, among them heat-shock proteins, cytokines, and antioxidant enzymes. Several studies have shown that angina pectoris before myocardial infarction represents a clinical correlate of experimental preconditioning protocols. Accordingly, evidence for a possible protective effect of transient ischemic attacks (TIAs) occurring before stroke are accumulating.

Seven legal barriers to end-of-life care: myths, realities, and grains of truth

OBJECTIVE

The American College of Physicians-American Society of Internal Medicine (ACP-ASIM) End-of-Life Care Consensus Panel was convened in 1997 to identify clinical, ethical, and policy problems in end-of-life care, to analyze critically the available evidence and guidelines, and to offer consensus recommendations on how to improve care of the dying. Topic selection and content presentation were carefully debated to maximize the project's focus on providing practical clinical and other guidance to clinicians who are not specialists in palliative care. This statement examines current legal myths, realities, and grains of truth in end-of-life care.

PARTICIPANTS

The Consensus Panel comprises 13 medical and bioethics experts, clinicians, and educators in care at the end of life selected by the Ethics and Human Rights Committee, College leadership, and the Center for Ethics and Professionalism at the ACP-ASIM.

EVIDENCE

A literature review including a MEDLINE search of articles from 1970-1998 and review of end-of-life care literature and organizational bibliographies was conducted. Unpublished sources were also identified by participants, as was anecdotal clinical experience.

CONSENSUS PROCESS

The draft statement was debated by panel members over a series of 3 to 4 meetings. For this statement, the initial draft and subsequent revised drafts were discussed in 1998-1999. The statement then underwent external peer review and revision before panel approval and the journal peer review process.

CONCLUSIONS

Legal myths about end-of-life care can undermine good care and ethical medical practice. In addition, at times ethics, clinical judgment, and the law conflict. Patients (or families) and physicians can find themselves considering clinical actions that are ethically appropriate, but raise legal concerns. The 7 major legal myths regarding end-of-life care are: (1) forgoing life-sustaining treatment for patients without decision-making capacity requires evidence that this was the patient's actual wish; (2) withholding or withdrawing of artificial fluids and nutrition from terminally ill or permanently unconscious patients is illegal; (3) risk management personnel must be consulted before life-sustaining medical treatment may be terminated; (4) advance directives must comply with specific forms, are not transferable between states, and govern all future treatment decisions; oral advance directives are unenforceable; (5) if a physician prescribes or administers high doses of medication to relieve pain or other discomfort in a terminally ill patient, resulting in death, he/she will be criminally prosecuted; (6) when a terminally ill patient's suffering is overwhelming despite palliative care, and he/she requests a hastened death, there are no legally permissible options to ease suffering; and (7) the 1997 Supreme Court decisions outlawed physician-assisted suicide. Many legal barriers to end-of-life care are more mythical than real, but sometimes there is a grain of truth. Physicians must know the law of the state in which they practice. JAMA. 2000;284:2495-2501.

DNA methyltransferase contributes to delayed ischemic brain injury

DNA methylation is important for controlling the profile of gene expression and is catalyzed by DNA methyltransferase (MTase), an enzyme that is abundant in brain. Because significant DNA damage and alterations in gene expression develop as a consequence of cerebral ischemia, we measured MTase activity in vitro and DNA methylation in vivo after mild focal brain ischemia. After 30 min middle cerebral artery occlusion (MCAo) and reperfusion, MTase catalytic activity and the 190 kDa band on immunoblot did not change over time. However, [(3)H]methyl-group incorporation into DNA increased significantly in wild-type mice after reperfusion, but not in mutant mice heterozygous for a DNA methyltransferase gene deletion (Dnmt(S/+)). Dnmt(S/+) mice were resistant to mild ischemic damage, suggesting that increased DNA methylation is associated with augmented brain injury after MCA occlusion. Consistent with this formulation, treatment with the MTase inhibitor 5-aza-2'-deoxycytidine and the deacetylation inhibitor trichostatin A conferred stroke protection in wild-type mice. In contrast to mild stroke, however, DNA methylation was not enhanced, and reduced dnmt gene expression was not protective in an ischemia model of excitotoxic/necrotic cell death. In conclusion, our results demonstrate that MTase activity contributes to poor tissue outcome after mild ischemic brain injury.

A fluorescence based non-radioactive electrophoretic mobility shift assay

Electrophoretic mobility shift assay (EMSA) or gel shift assay is one of the most powerful methods for studying protein-DNA interactions. Typically, 32P-labeled DNA probes containing the sequence bound by the protein of interest are used in EMSA (rEMSA). Although rEMSA is sensitive and practicable, it relies on the handling of hazardous radioisotopes, and does not easily allow quantification. We developed a non-radioactive procedure using fluorescence (Cyano dye Cy5) labeled oligodeoxynucleotide duplexes as specific probes (fEMSA) and an automatic DNA sequencer for analysis. Testing different DNA-binding proteins (restriction endonuclease EcoRII, transcription factor NFkappaB and it's subunit p50) the results in fEMSA and rEMSA are similar in regard to quality, reproducibility, and sensitivity. fEMSA allows a semiquantitative screening of large amounts of samples for specific DNA binding activities and is, therefore, a high throughput technology for semiquantitative analysis of DNA-protein interaction.

Respiratory chain inhibition induces tolerance to focal cerebral ischemia

The authors show that the inhibitor of the succinate dehydrogenase, 3-nitroproprionic acid (3-NPA), which in high doses and with chronic administration is a neurotoxin, can induce profound tolerance to focal cerebral ischemia in the rat when administered in a single dose (20 mg/kg) 3 days before ischemia. Infarcts were approximately 70% and 35% smaller in the 3-NPA preconditioned groups of permanent and transient focal cerebral ischemia, respectively. This regimen of 3-NPA preconditioning neither induced necrosis, apoptosis, or any other histologically detectable damage to the brain, nor did it affect behavior of the animals. 3-NPA led to an immediate (1-hour) and long-lasting (3-day) decrease in succinate dehydrogenase activity (30% reduction) throughout the brain, whereas only a short metabolic impairment occurred (ATP decrease of 35% within 30 minutes, recovery within 2 hours). The authors found that 3-NPA induces a burst of reactive oxygen species and the free radical scavenger dimethylthiourea, when administered shortly before the 3-NPA stimulus, completely blocked preconditioning. Inhibition of protein synthesis with cycloheximide given at the time of 3-NPA administration completely inhibited preconditioning. The authors were unsuccessful in showing upregulation of mRNA for the manganese superoxide dismutase, and did not detect increased activities of the copper-zinc and manganese superoxide dismutases, prototypical oxygen free radicals scavenging enzymes, after 3-NPA preconditioning. The authors conclude that it is possible to pharmacologically precondition the brain against focal cerebral ischemia, a strategy that may in principal have clinical relevance. The data show the relevance of protein synthesis for tolerance, and suggests that oxygen free radicals may be critical signals in preconditioning.

Cerebral endothelial cells release TNF-alpha after stimulation with cell walls of Streptococcus pneumoniae and regulate inducible nitric oxide synthase and ICAM-1 expression via autocrine loops

TNF-alpha, inducible NO synthase (iNOS), and ICAM-1 are considered to be key proteins in the inflammatory response of most tissues. We tested the hypothesis that cell walls of Streptococcus pneumoniae (PCW), the most common cause of adult bacterial meningitis, induce TNF-alpha, iNOS, and ICAM-1 expression in rat primary brain microvascular endothelial cell cultures. We detected TNF-alpha mRNA by RT-PCR already 1 h after stimulation with PCW, while TNF-alpha protein peaked at 4 h (9.4 +/- 3.6 vs 0.1 +/- 0.1 pg/microgram protein). PCW induced iNOS mRNA 2 h after stimulation, followed by an increase of the NO degradation product nitrite (18.1 +/- 4 vs 5.8 +/- 1.8 at 12 h; 18.1 +/- 4 vs 5.8 +/- 1.8 pmol/microgram protein at 72 h). The addition of TNF-alpha Ab significantly reduced nitrite production to 62.2 +/- 14.4% compared with PCW-stimulated brain microvascular endothelial cells (100%). PCW induced the expression of ICAM-1 (measured by FACS), which was completely blocked by TNF-alpha Ab (142 +/- 18.6 vs 97.5 +/- 12.4%; 100% unstimulated brain microvascular endothelial cells). Cerebral endothelial cells express TNF-alpha mRNA as well as iNOS mRNA and release the bioactive proteins in response to PCW. PCW-induced NO production is mediated in part by an autocrine pathway involving TNF-alpha, whereas ICAM-1 expression is completely mediated by this autocrine loop. By these mechanisms, cerebral endothelial cells may regulate critical steps in inflammatory blood-brain-barrier disruption of bacterial meningitis.

Induction of ischemic tolerance in rat cortical neurons by 3-nitropropionic acid: chemical preconditioning

Sublethal ischemia leads to increased tolerance against subsequent ischemia. We investigated whether tolerance could also be elicited by mild respiratory-chain inhibition (chemical hypoxia) in a rat neuronal-cell enriched culture system. 3-Nitropropionic acid (3-NPA) caused a concentration-dependent inhibition of succinate-dehydrogenase. Two hours preconditioning with 3-NPA 24-48 h before oxygen-glucose deprivation (OGD) reduced neuronal damage morphologically and reduced lactate deydrogenase (LDH) release up to 72% compared to sham-treated sister cultures without 3-NPA. In an attempt to elucidate transcriptional mechanisms, we found no rapid translocation of the hypoxia-sensitive transcription factors N F-KB or hypoxia-inducible factor-I (HIF-I) at 3-NPA concentrations sufficient to trigger tolerance against OGD. In accordance to previous in vivo and brain slice data, we conclude that 3-NPA chemically induces tolerance against oxygen-glucose deprivation in vitro. However, the underlying mechanisms remain elusive.