Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0004134 (ataxia)
15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We describe here familial dyskinesia and facial myokymia (FDFM), a novel autosomal dominant disorder characterized by adventitious movements that sometimes appear choreiform and that are associated with perioral and periorbital myokymia. We report a 5-generation family with 18 affected members (10 males and 8 females) with FDFM. The disorder has an early childhood or adolescent onset. The involuntary movements are paroxysmal at early ages, increase in frequency and severity, and may become constant in the third decade. Thereafter, there is no further deterioration, and there may even be improvement in old age. The adventitious movements are worsened by anxiety but not by voluntary movement, startle, caffeine, or alcohol. The disease is socially disabling, but there is no intellectual impairment or decrease in lifespan. A candidate gene and haplotype analysis was performed in 9 affected and 3 unaffected members from 3 generations of this family using primers for polymorphic loci closely flanking or within genes of interest. We excluded linkage to 11 regions containing genes associated with chorea and myokymia: 1) the Huntington disease gene on chromosome 4p; 2) the paroxysmal dystonic choreoathetosis gene at 2q34; 3) the dentatorubral-pallidoluysian atrophy gene at 12p13; 4) the choreoathetosis/spasticity disease locus on 1p that lies in a region containing a cluster of potassium (K+) channel genes; 5) the episodic ataxia type 1 (EA1) locus on 12p that contains the KCNA1 gene and two other voltage-gated K+ channel genes, KCNA5 and KCNA6; 6) the chorea-acanthocytosis locus on 9q21; 7) the Huntington-like syndrome on 20p; 8) the paroxysmal kinesigenic dyskinesia locus on 16p11.2-q11.2; 9) the benign hereditary chorea locus on 14q; 10) the SCA type 5 locus on chromosome 11; and 11) the chromosome 19 region that contains several ion channels and the CACNA1A gene, a brain-specific P/Q-type calcium channel gene associated with ataxia and hemiplegic migraine. Our results provide further evidence of genetic heterogeneity in autosomal dominant movement disorders and suggest that a novel gene underlies this new condition.
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PMID:Familial dyskinesia and facial myokymia (FDFM): a novel movement disorder. 1131 Jun 26

Interactions between the checkpoint abrogator UCN-01 and several pharmacological inhibitors of the mitogen-activated protein kinase (MAPK) kinase (MEK)/MAPK pathway have been examined in a variety of human leukemia cell lines. Exposure of U937 monocytic leukemia cells to a marginally toxic concentration of UCN-01 (e.g., 150 nM) for 18 h resulted in phosphorylation/activation of p42/44 MAPK. Coadministration of the MEK inhibitor PD184352 (10 microM) blocked UCN-01-induced MAPK activation and was accompanied by marked mitochondrial damage (e.g., cytochrome c release and loss of DeltaPsi(m)), caspase activation, DNA fragmentation, and apoptosis. Similar interactions were noted in the case of other MEK inhibitors (e.g., PD98059; U0126) as well as in multiple other leukemia cell types (e.g., HL-60, Jurkat, CCRF-CEM, and Raji). Coadministration of PD184352 and UCN-01 resulted in reduced binding of the cdc25C phosphatase to 14-3-3 proteins, enhanced dephosphorylation/activation of p34(cdc2), and diminished phosphorylation of cyclic AMP-responsive element binding protein. The ability of UCN-01, when combined with PD184352, to antagonize cdc25C/14-3-3 protein binding, promote dephosphorylation of p34(cdc2), and potentiate apoptosis was mimicked by the ataxia telangectasia mutation inhibitor caffeine. In contrast, cotreatment of cells with UCN-01 and PD184352 did not substantially increase c-Jun-NH(2)-terminal kinase activation nor did it alter expression of Bcl-2, Bcl-x(L), Bax, or X-inhibitor of apoptosis. However, coexposure of U937 cells to UCN-01 and PD184352 induced a marked increase in p38 MAPK activation. Moreover, SB203580, which inhibits multiple kinases including p38 MAPK, partially antagonized cell death. Lastly, although UCN-01 +/- PD184352 did not induce p21(CIP1), stable expression of a p21(CIP1) antisense construct significantly increased susceptibility to this drug combination. Together, these findings indicate that exposure of leukemic cells to UCN-01 leads to activation of the MAPK cascade and that interruption of this process by MEK inhibition triggers perturbations in several signaling and cell cycle regulatory pathways that culminate in mitochondrial injury, caspase activation, and apoptosis. They also raise the possibility that disrupting multiple signaling pathways, e.g., by combining UCN-01 with MEK inhibitors, may represent a novel antileukemic strategy.
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PMID:Pharmacological inhibitors of the mitogen-activated protein kinase (MAPK) kinase/MAPK cascade interact synergistically with UCN-01 to induce mitochondrial dysfunction and apoptosis in human leukemia cells. 1143 48

Camptothecin (CPT) that targets DNA topoisomerase I is one of the most promising broad-spectrum anticancer drugs in development today. The cytotoxicity of CPT is S phase (S)-specific because the collision of advancing replication forks with CPT-topoisomerase I-DNA complexes results in DNA damage. After DNA damage, proliferating cells could actively slow down the DNA replication through an S checkpoint to provide time for repair. We report now that there is an activated S checkpoint response in CPT-treated mammalian cells. This response is regulated by Ataxia and Rad3-related (ATR)/CHK1 pathway. Compared with their wild-type counterparts, CPT-treated Ku80-/- cells showed stronger inhibition of DNA replication. This stronger inhibition had no relationship with DNA-dependent protein kinase (DNA-PK) activity but correlated with the higher activities of ATR and the higher activities of CHK1 in such cells. Not only caffeine, the nonspecific inhibitor of ATR, or UCN-01, the nonspecific inhibitor of CHK1, but also the specific CHK1 antisense oligonucleotide abolished the stronger inhibition of DNA replication in CPT-treated Ku80-/- cells. These results in aggregate indicated that the stronger S checkpoint in CPT-treated Ku80-/- cells is regulated through the highly activated ATR/CHK1 pathway.
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PMID:Ku affects the ataxia and Rad 3-related/CHK1-dependent S phase checkpoint response after camptothecin treatment. 1198 Jun 37

Ataxia teleangiectasia mutated (ATM) kinase, ATM-Rad3-related (ATR) kinase and DNA-protein kinase (DNA-PK) belong to a subgroup of protein kinases which play a role in the DNA damage response. In this study, cisplatin was shown to increase ATR activity and decrease ATM and DNA-PK activity. Caffeine, a nonspecific inhibitor of ATR, enhanced the cytotoxic effect of cisplatin, modestly decreased the p53 and p21WAF-1 response to cisplatin, and affected the cdc2-p34/cyclin B1 complex by decreasing both cyclin B1 protein accumulation and cdc2-p34 tyrosine 15 phosphorylation. The observed alteration of several potential ATR downstream targets suggests that inhibition of ATR activity may be one of the mechanism by which caffeine regulates sensitivity to cisplatin.
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PMID:Inhibition of cisplatin-induced ATR activity and enhanced sensitivity to cisplatin. 1289 3

N-Methyl-D-aspartate (NMDA) receptor antagonists cause hyperlocomotion and cognitive deficits in rodents, and caffeine-tolerant mice show diminished locomotor response to NMDA receptor antagonists. The aim of this study was to evaluate the effect of subchronic caffeine treatment on MK-801-induced hyperlocomotion, ataxia and cognitive deficits, as well as amphetamine-induced hyperlocomotion in mice. Mice were treated subchronically with caffeine (0, 0.1, 0.3 and 1 mg/ml and 1, 3 and 7 days) and evaluated for locomotor activity, working memory (delayed alternation test), long-term memory (inhibitory avoidance task) and ataxia. Hyperlocomotion induced by MK-801 (0.25 mg/kg i.p.) was diminished after 3 days and almost abolished after 7 days of caffeine treatment at the 1 mg/ml dose, and this effect was also dose-dependent. Ataxia induced by 0.5 mg/kg MK-801 was not affected by caffeine treatment, but a short-lived hyperlocomotor effect was observed. Performance deficit in the inhibitory avoidance task induced by MK-801 (0.01 mg/kg) was prevented in mice treated with caffeine for 7 days at 1 mg/ml, and perseverative errors in the T-maze by MK-801 (0.4 mg/kg) were attenuated. The locomotor effect of amphetamine (5 mg/kg) was unaffected by subchronic caffeine treatment. The findings that hyperlocomotion and cognitive effects induced by MK-801 can be specifically influenced by reduced adenosinergic activity agree with a model of adenosine hypofunction in schizophrenia, since NMDA receptor antagonists are pharmacological models for this disorder.
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PMID:Effect of subchronic caffeine treatment on MK-801-induced changes in locomotion, cognition and ataxia in mice. 1576 42

Humans with the disorder episodic ataxia type 2 (EA2) and the tottering mouse mutant exhibit episodic attacks induced by emotional and chemical stress. Both the human and mouse disorders result from mutations in CACNA1A, the gene encoding the alpha(1)2.1 subunit of Ca(v)2.1 voltage-gated calcium channels. These mutations predict reduced calcium currents, particularly in cerebellar Purkinje cells, where these channels are most abundant. 4-Aminopyridine (4-AP), a nonselective blocker of K(v) voltage-gated potassium channels, alleviates attacks of ataxia in EA2 patients. To test the specificity of the effect for K(v) channels, aminopyridine analogs were assessed for their ability to ameliorate attacks of dyskinesia in tottering mice. 4-AP and 3,4-diaminopyridine (3,4-DiAP), which have relatively high affinities for K(v) channels, reduced the frequency of restraint- and caffeine-induced attacks. Furthermore, microinjection of 3,4-DiAP into the cerebellum completely blocked attacks in tottering mice. Other aminopyridine analogs reduced attack frequency but, consistent with their lower affinities for K(v) channels, required comparatively higher doses. These results suggest that aminopyridines block tottering mouse attacks via cerebellar K(v) channels. That both stress- and caffeine-induced attacks were blocked by aminopyridines suggests that these triggers act via similar mechanisms. Although 4-AP and 3,4-DiAP were effective in preventing attacks in tottering mice, these compounds did not affect the severity of "breakthrough" attacks that occurred in the presence of a drug. These results suggest that the aminopyridines increase the threshold for attack initiation without mitigating the character of the attack, indicating that attack initiation is mediated by mechanisms that are independent of the neurological phenotype.
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PMID:Potassium channel blockers inhibit the triggers of attacks in the calcium channel mouse mutant tottering. 1584 17

Genotoxic treatments, such as UV light, camptothecin, and adozelesin, stall DNA replication and subsequently generate DNA strand breaks. Typically, DNA breaks are reflected by an increase in ataxia and Rad-related kinase (ATR)-regulated phosphorylation of H2AX (gammaH2AX) and require replication fork movement. This study examined the potential of the monofunctional DNA alkylating agent hedamycin, a powerful inhibitor of DNA replication, to induce DNA strand breaks, phosphorylated H2AX (gammaH2AX) foci, and chromosome aberrations. Hedamycin treatment of HCT116 carcinoma cells resulted in a rapid induction of DNA strand breaks accompanied by increasing H2AX phosphorylation and focalization. Unlike many other treatments that also stall replication, such as UV, camptothecin, and adozelesin, gammaH2AX formation was not suppressed in ATR-compromised cells but actually increased. Similarly, hedamycin induction of gammaH2AX is not dependent on ataxia telangiectasia mutated or DNA-protein kinase, and pretreatment of cells with the phosphatidylinositol 3-kinase-related kinase inhibitor caffeine did not substantially reduce induction of H2AX phosphorylation by hedamycin. Furthermore, the DNA replication inhibitor aphidicolin only modestly depressed hedamycin-induced gammaH2AX formation, indicating that hedamycin-induced DNA double-strand breaks are not dependent on fork progression. In contrast, camptothecin- and adozelesin-induced gammaH2AX was strongly suppressed by aphidicolin. Moreover, after 24 hours following a short-term hedamycin treatment, cells displayed high levels of breaks in interphase nuclear DNA and misjoined chromosomes in metaphase cells. Finally, focalization of a tightly bound form of Ku80 was observed in interphase cells, consistent with the subsequent appearance of chromosomal aberrations via abnormal nonhomologous end joining. Overall, this study has revealed a disparate type of DNA damage response to stalled replication induced by a bulky DNA adduct inducer, hedamycin, that seems not to be highly dependent on ATR or DNA replication.
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PMID:Hedamycin, a DNA alkylator, induces (gamma)H2AX and chromosome aberrations: involvement of phosphatidylinositol 3-kinase-related kinases and DNA replication fork movement. 1609 33

We describe four families with late onset episodic vertical oscillopsia and progressive gait ataxia. Probands presented between the ages of 40 and 64 years with initial symptoms of episodic vertical oscillopsia and interictal downbeat nystagmus. A mild gait ataxia developed over several years. Triggers included physical exertion, alcohol and caffeine. Patients did not respond to acetazolamide. Genetic screening for episodic ataxia types 1 and 2, and spinocerebellar ataxias 1, 2, 3 and 6 were negative. Using ancestral identity by descent analysis and dense single nucleotide polymorphism (SNP) genotyping throughout the genome, an interval of 28.6 cM (approximately 14.2 Mb) on chromosome 13q12.11-q13.3, composed of 1259 SNPs, was shared between affected individuals in two of the four families and highlighted a region of suggestive linkage (LOD >2.7).
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PMID:Episodic vertical oscillopsia with progressive gait ataxia: clinical description of a new episodic syndrome and evidence of linkage to chromosome 13q. 1752 1

Ma Huang (equivalent to 0, 12.5, 25, or 50 mg/kg ephedrine) or ephedrine (0, 6.25, 12.5, 25 mg/kg) were administered as one bolus oral dose to male F344 rats with and without caffeine. The herbal medicine Ma Huang (ephedra) in combination with caffeine caused rapid clinical signs of toxicity including salivation, hyperactivity, ataxia, and eventually lethargy, and failure to respond to stimuli. When this syndrome of clinical signs emerged, animals were moribund sacrificed, and a histological analysis for heart lesions performed. Cardiotoxicity included hemorrhage, necrosis, and degeneration in the ventricles or interventricular septum within 2-4 hours after treatment with Ma Huang (ephedra)/caffeine or ephedrine (the principal active component in Ma Huang)/caffeine. There was a steep dose response curve for cardiotoxicity with minimal toxicity seen at levels of Ma Huang (equivalent to 12.5 mg/kg ephedrine) with caffeine. However, cardiotoxic lesions occurred in 28% of animals with Ma Huang dosages equivalent to 25 mg/kg ephedrine with 15 or 30 mg/kg caffeine, and in 90% of animals at Ma Huang exposures equivalent to 50 mg/kg ephedrine with 15 or 30 mg/kg caffeine. Cardiotoxic lesions occurred in 47% of animals in the 25 mg/kg ephedrine groups with caffeine at 7.25, 15, or 30 mg/kg. There was no statistical difference in the occurrence of cardiotoxic lesions when 15 or 30 mg/kg caffeine was combined with Ma Huang equivalent to 25 or 50 mg/kg ephedrine; likewise there was no statistical difference in the occurrence of cardiotoxic lesions when 7.25, 15, or 30 mg/kg caffeine was combined with 25 mg/kg ephedrine. These results show that the cardiotoxic effects of the herbal medicine, Ma Huang, are similar to that of ephedrine, the principal active ingredient in the herbal medicine. The combination of Ma Huang or ephedrine with caffeine enhanced the cardiotoxicity over that with the herbal medicine or the active ingredient alone.
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PMID:Cardiotoxicity of Ma Huang/caffeine or ephedrine/caffeine in a rodent model system. 1767 24

Mammalian ultraviolet (UV) radiation response is a gene induction cascade activated by several transcription factors, including NF-kappaB. Although NF-kappaB is induced by UV radiation, the signal transduction mechanism remains relatively unclear. In the present study, we show that UV-induced NF-kappaB activation is mediated by the activation of Ataxia telangiecia mutated (ATM) and protein kinase C (PKC). We also show that caffeine specifically inhibits UV-mediated NF-kappaB activation, but not TNFalpha-mediated NF-kappaB activation. In addition, our study shows that ATM, but not ATM-Rad3-related (ATR) or DNA-dependent protein kinase (DNA-PK) is involved in UV-induced NF-kappaB activation. Because SB203580 (a p38 MAPK inhibitor), or Calphostin C or rottlerin (PKC inhibitors) was able to inhibit UV-mediated NF-kappaB activation, we evaluated whether caffeine could inhibit p38 MAPK or PKC activity. Caffeine or rottlerin inhibited UV-induced phosphorylation of p38 MAPK, but not anisomycin-induced phosphorylation of p38 MAPK, suggesting that p38 MAPK is downstream of PKC. Additionally, caffeine could effectively inhibit UV-induced increases in PKC activity. Taken together, our study demonstrates that caffeine is a potent inhibitor of UV-induced NF-kappaB activation. Additionally, this inhibition occurs due to the inhibitory action of caffeine on ATM and PKC, resulting in the inhibition of p38 MAPK activation.
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PMID:Caffeine inhibits UV-mediated NF-kappaB activation in A2058 melanoma cells: an ATM-PKCdelta-p38 MAPK-dependent mechanism. 1793 22


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