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We investigated whether soticlestat (TAK-935), a newly discovered cholesterol 24-hydroxylase (CH24H) inhibitor now in phase 3 clinical trials for Dravet and Lennox-Gastaut syndromes, has effects on neurodegeneration in both chronic and acute animal models associated with glutamate hyperexcitation. Soticlestat was administered at doses that approximately halve 24S-hydroxycholesterol in both experiments. In the kainic acid (KA)-induced acute hippocampal degeneration model, soticlestat ameliorated inflammatory cytokine expression, hippocampal degeneration, and memory impairment. We ruled out the possibility that soticlestat directly interferes with KA binding to the KA receptor, or that 24S-hydroxycholesterol modulates KA receptor signaling, by conducting receptor binding and cell death assays. In the PS19 chronic degeneration model of tauopathy, treatment effects were observed in neurodegeneration markers. Notably, there was a significant correlation between the levels of brain 24S-hydroxycholesterol and a proinflammatory cytokine, tumor necrosis factor-α, which is implicated in cognitive decline and lowering of seizure threshold. This is the first study demonstrating that CH24H inhibition can alleviate neurodegeneration concomitant with neuroinflammation. Herein, we discuss the interplay among 24S-hydroxycholesterol production, neuroinflammation, and excitotoxicity. Effects on neurodegeneration and neuroinflammation demonstrated in two preclinical models suggest that soticlestat is effective in ameliorating seizures and addressing cognitive dysfunction in seizure disorders.
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Treatment guidelines for esophageal squamous cell carcinoma (ESCC) with concomitant esophageal varices (EVs), which increase the risk of bleeding, are unavailable. A 66-year-old man with a history of total gastrectomy was admitted to the hospital owing to hematemesis. Emergency upper gastrointestinal endoscopy revealed variceal bleeding near the anastomosis between the esophagus and jejunum, and endoscopic clipping stopped the bleeding. Upper gastrointestinal endoscopy following hemostasis revealed four EVs and a two-thirds ESCC circumference. The ESCC depth was suspected to be up to the mucosa. The patient underwent intravariceal endoscopic injection sclerotherapy (EIS) for EVs, followed by paravariceal EIS. However, after these treatments, blood flow in the EVs just below the ESCC remained, and endoscopic resection of the ESCC was judged to be difficult to perform. Therefore, we prioritized EV treatment and performed a second EIS on the ESCC, followed by argon plasma coagulation (APC). APC was expected to not only solidify the EVs but also eliminate the ESCC existing in the mucosa. Finally, EVs and ESCC were treated by EIS and APC. EIS followed by APC may be useful for treating concurrent EVs and intramucosal ESCC in patients with liver cirrhosis when embolization of the EVs is ineffective.
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OBJECTIVE: The formation of 24S-hydroxycholesterol is a brain-specific mechanism of cholesterol catabolism catalyzed by cholesterol 24-hydroxylase (CYP46A1, also known as CH24H). CH24H has been implicated in various biological mechanisms, whereas pharmacological lowering of 24S-hydroxycholesterol has not been fully studied. Soticlestat is a novel small-molecule inhibitor of CH24H. Its therapeutic potential was previously identified in a mouse model with an epileptic phenotype. In the present study, the anticonvulsive property of soticlestat was characterized in rodent models of epilepsy that have long been used to identify antiseizure medications. METHODS: The anticonvulsive property of soticlestat was investigated in maximal electroshock seizures (MES), pentylenetetrazol (PTZ) acute seizures, 6-Hz psychomotor seizures, audiogenic seizures, amygdala kindling, PTZ kindling, and corneal kindling models. Soticlestat was characterized in a PTZ kindling model under steady-state pharmacokinetics to relate its anticonvulsive effects to pharmacodynamics. RESULTS: Among models of acutely evoked seizures, whereas anticonvulsive effects of soticlestat were identified in Frings mice, a genetic model of audiogenic seizures, it was found ineffective in MES, acute PTZ seizures, and 6-Hz seizures. The protective effects of soticlestat against audiogenic seizures increased with repetitive dosing. Soticlestat was also tested in models of progressive seizure severity. Soticlestat treatment delayed kindling acquisition, whereas fully kindled animals were not protected. Importantly, soticlestat suppressed the progression of seizure severity in correlation with 24S-hydroxycholesterol lowering in the brain, suggesting that 24S-hydroxycholesterol can be aggressively reduced to produce more potent effects on seizure development in kindling acquisition. SIGNIFICANCE: The data collectively suggest that soticlestat can ameliorate seizure symptoms through a mechanism distinct from conventional antiseizure medications. With its novel mechanism of action, soticlestat could constitute a novel class of antiseizure medications for treatment of intractable epilepsy disorders such as developmental and epileptic encephalopathy.
Assuntos
Epilepsia , Excitação Neurológica , Animais , Anticonvulsivantes/farmacologia , Anticonvulsivantes/uso terapêutico , Colesterol 24-Hidroxilase/metabolismo , Modelos Animais de Doenças , Epilepsia/tratamento farmacológico , Camundongos , Pentilenotetrazol/toxicidade , Piperidinas/farmacologia , Piridinas/farmacologia , Convulsões/tratamento farmacológicoAssuntos
Neoplasias da Mama , Histiocitoma Fibroso Benigno , Neoplasias Cutâneas , Neoplasias da Mama/diagnóstico , Diagnóstico Diferencial , Feminino , Histiocitoma Fibroso Benigno/diagnóstico , Histiocitoma Fibroso Benigno/patologia , Humanos , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/patologiaRESUMO
BACKGROUND: Long-acting injectable (LAI) antipsychotics improve medication adherence in patients with schizophrenia and extend the duration of therapeutic drug levels but with administration of an increased dose. Real-world mortality data in patients prescribed LAIs are lacking. We conducted a population-based cohort study to estimate and compare the incidence rates of all-cause death and completed suicide in patients with schizophrenia/schizoaffective disorder exposed to LAIs and oral antipsychotics. METHODS: Patients with a diagnosis of schizophrenia/schizoaffective disorder between January 1, 2015 and November 30, 2019 were enrolled from the Taiwan National Health Insurance Research Database and linked to Death Registry records. Eligible patients were new antipsychotic users. Relative risks of death for each antipsychotic compared with oral paliperidone were evaluated using a Cox proportional hazard model adjusted for age, sex, Charlson Comorbidity Index, index year, bipolar or major depressive or other mood disorders, mental disorders due to drug use, and baseline hospitalization frequency. RESULTS: There were 228,791.08 person-years of follow-up (mean 2.48 years). The incidence rates of all-cause death in users of LAI paliperidone administered monthly (PP1M) and every 3 months (PP3M) were 7.40/1,000 person-years (95% confidence interval 5.94-9.11) and 9.93 (5.88-15.79), respectively. The incidences of completed suicide were 2.03/1,000 person-years (1.32-2.99) and 3.10 (1.14-6.88), respectively. No significant associations were observed between PP1M and PP3M compared to oral paliperidone in incidences of all-cause death or for completed suicide. DISCUSSION: No increased risk of all-cause death or completed suicide was observed in users of antipsychotic LAIs, including PP1M and PP3M.
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Antipsicóticos , Transtorno Depressivo Maior , Transtornos Psicóticos , Esquizofrenia , Suicídio Consumado , Antipsicóticos/efeitos adversos , Estudos de Coortes , Preparações de Ação Retardada/uso terapêutico , Transtorno Depressivo Maior/tratamento farmacológico , Humanos , Transtornos Psicóticos/tratamento farmacológico , Transtornos Psicóticos/epidemiologia , Estudos Retrospectivos , Esquizofrenia/tratamento farmacológico , Taiwan/epidemiologiaRESUMO
Genetic diversity, knowledge of the genetic architecture of the traits of interest and efficient means of transferring the desired genetic diversity into the relevant genetic background are prerequisites for plant breeding. Exotic germplasm is a rich source of genetic diversity; however, they harbor undesirable traits that limit their suitability for modern agriculture. Nested association mapping (NAM) populations are valuable genetic resources that enable incorporation of genetic diversity, dissection of complex traits and providing germplasm to breeding programs. We developed the OzNAM by crossing and backcrossing 73 diverse exotic parents to two Australian elite varieties Gladius and Scout. The NAM parents were genotyped using the iSelect wheat 90K Infinium SNP array, and the progeny were genotyped using a custom targeted genotyping-by-sequencing assay based on molecular inversion probes designed to target 12,179 SNPs chosen from the iSelect wheat 90K Infinium SNP array of the parents. In total, 3535 BC1F4:6 RILs from 125 families with 21 to 76 lines per family were genotyped and we found 4964 polymorphic and multi-allelic haplotype markers that spanned the whole genome. A subset of 530 lines from 28 families were evaluated in multi-environment trials over three years. To demonstrate the utility of the population in QTL mapping, we chose to map QTL for maturity and plant height using the RTM-GWAS approach and we identified novel and known QTL for maturity and plant height.
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Mudança Climática , Estudo de Associação Genômica Ampla , Melhoramento Vegetal/métodos , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Triticum/crescimento & desenvolvimento , Triticum/genética , Pão , Mapeamento Cromossômico , Genótipo , FenótipoRESUMO
Nitrogen is an essential nutrient for plants, but crop plants are inefficient in the acquisition and utilization of applied nitrogen. This often results in producers over applying nitrogen fertilizers, which can negatively impact the environment. The development of crop plants with more efficient nitrogen usage is, therefore, an important research goal in achieving greater agricultural sustainability. We utilized genetically modified rice lines over-expressing a barley alanine aminotransferase (HvAlaAT) to help characterize pathways which lead to more efficient use of nitrogen. Under the control of a stress-inducible promoter OsAnt1, OsAnt1:HvAlaAT lines have increased above-ground biomass with little change to both nitrate and ammonium uptake rates. Based on metabolic profiles, carbon metabolites, particularly those involved in glycolysis and the tricarboxylic acid (TCA) cycle, were significantly altered in roots of OsAnt1:HvAlaAT lines, suggesting higher metabolic turnover. Moreover, transcriptomic data revealed that genes involved in glycolysis and TCA cycle were upregulated. These observations suggest that higher activity of these two processes could result in higher energy production, driving higher nitrogen assimilation, consequently increasing biomass production. Other potential mechanisms contributing to a nitrogen-use efficient phenotype include involvements of phytohormonal responses and an alteration in secondary metabolism. We also conducted basic growth studies to evaluate the effect of the OsAnt1:HvAlaAT transgene in barley and wheat, which the transgenic crop plants increased seed production under controlled environmental conditions. This study provides comprehensive profiling of genetic and metabolic responses to the over-expression of AlaAT and unravels several components and pathways which contribute to its nitrogen-use efficient phenotype.
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Cholesterol 24-hydroxylase (CH24H) is a brain-specific enzyme that converts cholesterol into 24S-hydroxycholesterol, the primary mechanism of cholesterol catabolism in the brain. The therapeutic potential of CH24H activation has been extensively investigated, whereas the effects of CH24H inhibition remain poorly characterized. In this study, the therapeutic potential of CH24H inhibition was investigated using a newly identified small molecule, soticlestat (TAK-935/OV935). The biodistribution and target engagement of soticlestat was assessed in mice. CH24H-knockout mice showed a substantially lower level of soticlestat distribution in the brain than wild-type controls. Furthermore, brain-slice autoradiography studies demonstrated the absence of [3H]soticlestat staining in CH24H-knockout mice compared with wild-type mice, indicating a specificity of soticlestat binding to CH24H. The pharmacodynamic effects of soticlestat were characterized in a transgenic mouse model carrying mutated human amyloid precursor protein and presenilin 1 (APP/PS1-Tg). These mice, with excitatory/inhibitory imbalance and short life-span, yielded a remarkable survival benefit when bred with CH24H-knockout animals. Soticlestat lowered brain 24S-hydroxycholesterol in a dose-dependent manner and substantially reduced premature deaths of APP/PS1-Tg mice at a dose lowering brain 24S-hydroxycholesterol by approximately 50%. Furthermore, microdialysis experiments showed that soticlestat can suppress potassium-evoked extracellular glutamate elevations in the hippocampus. Taken together, these data suggest that soticlestat-mediated inhibition of CH24H may have therapeutic potential for diseases associated with neural hyperexcitation.
Assuntos
Colesterol 24-Hidroxilase/antagonistas & inibidores , Inibidores das Enzimas do Citocromo P-450/farmacologia , Piperidinas/farmacologia , Piridinas/farmacologia , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encefalopatias/tratamento farmacológico , Encefalopatias/metabolismo , Encefalopatias/fisiopatologia , Colesterol 24-Hidroxilase/deficiência , Colesterol 24-Hidroxilase/genética , Inibidores das Enzimas do Citocromo P-450/química , Inibidores das Enzimas do Citocromo P-450/farmacocinética , Modelos Animais de Doenças , Desenvolvimento de Medicamentos , Feminino , Humanos , Hidroxicolesteróis/metabolismo , Longevidade/efeitos dos fármacos , Longevidade/genética , Longevidade/fisiologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Piperidinas/química , Piperidinas/farmacocinética , Presenilina-1/genética , Presenilina-1/metabolismo , Piridinas/química , Piridinas/farmacocinética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMO
BACKGROUND/AIM: Dose-dense doxorubicin and cyclophosphamide (ddAC) followed by dose-dense paclitaxel (ddP) (ddAC-P) has improved disease-free survival of patients with breast cancer. The aim of this study was to evaluate the safety and relative dose intensity (RDI) of ddAC-P administered together with pegfilgrastim. PATIENTS AND METHODS: Between May 2015 and Aug 2017, 44 patients were retrospectively reviewed; they were administered 4 cycles of ddAC, followed by 4 cycles of ddP. Pegfilgrastim (3.6 mg) was administered in every cycle. RESULTS: The mean RDIs for ddAC-P, ddAC, and ddP were 95.0%, 94.5%, and 93.3%, respectively. The prevalence of high RDIs (≥85%) for ddAC-P, ddAC, and ddP was 90.9%, 84.1%, and 88.6%, respectively. Seven of the 10 patients with low RDIs experienced grade 1 or 2 fever. CONCLUSION: DdAC-P administered together with pegfilgrastim (3.6 mg) appears to be feasible and maintains RDI in most of Japanese patients with breast cancer. Rapid evaluation and proper management of fever may prevent low RDI.
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Neoplasias da Mama/tratamento farmacológico , Ciclofosfamida/administração & dosagem , Doxorrubicina/administração & dosagem , Paclitaxel/administração & dosagem , Adulto , Idoso , Neoplasias da Mama/patologia , Ciclofosfamida/efeitos adversos , Relação Dose-Resposta a Droga , Doxorrubicina/efeitos adversos , Feminino , Filgrastim/administração & dosagem , Humanos , Pessoa de Meia-Idade , Paclitaxel/efeitos adversos , Polietilenoglicóis/administração & dosagemRESUMO
It has been suggested that patients with motor neurone disease (MND) and those with MND combined with behavioural variant frontotemporal dementia (bvFTD) (ie FTD + MND) or with FTD alone might exist on a continuum based on commonalities of neuropathology and/or genetic risk. Moreover, it has been reported that both a neuronal and a glial cell tauopathy can accompany the TDP-43 proteinopathy in patients with motor neurone disease (MND) with cognitive changes, and that the tauopathy may be fundamental to disease pathogenesis and clinical phenotype. In the present study, we sought to substantiate these latter findings, and test this concept of a pathological continuum, in a consecutive series of 41 patients with MND, 16 with FTD + MND and 23 with FTD without MND. Paraffin sections of frontal, entorhinal, temporal and occipital cortex and hippocampus were immunostained for tau pathology using anti-tau antibodies, AT8, pThr(175) and pThr(217), and for amyloid ß protein (Aß) using 4G8 antibody. Twenty four (59 %) patients with MND, 7 (44 %) patients with FTD + MND and 10 (43 %) patients with FTD showed 'significant' tau pathology (ie more than just an isolated neurofibrillary tangle or a few neuropil threads in one or more brain regions examined). In most instances, this bore the histological characteristics of an Alzheimer's disease process involving entorhinal cortex, hippocampus, temporal cortex, frontal cortex and occipital cortex in decreasing frequency, accompanied by a deposition of Aß up to Thal phase 3, though 2 patients with MND, and 1 with FTD did show tau pathology beyond Braak stage III. Four other patients with MND showed novel neuronal tau pathology, within the frontal cortex alone, specifically detected by pThr(175) antibody, which was characterised by a fine granular or more clumped aggregation of tau without neurofibrillary tangles or neuropil threads. However, none of these 4 patients had clinically evident cognitive disorder, and this type of tau pathology was not seen in any of the FTD + MND or FTD patients. Finally, two patients, one with MND and one with FTD, showed a tau pathology consistent with Argyrophilic Grain Disease (AGD). Western blotting and use of 3- and 4-repeat tau antibodies confirmed the histological interpretation of Alzheimer's disease type pathology in all instances except for those patients with accompanying AGD where a banding pattern on western blot, and immunohistochemistry, confirmed 4-repeat tauopathy. In all 3 patient groups, amyloid pathology was more likely to be present in patients dying after 65 years of age, and in the presence of APOE ε4 allele. We conclude that tau pathological changes are equally common amongst patients with MND, FTD + MND and FTD though, in most instances, these are limited in extent. In patients with MND, when cognitive impairment is present this is most likely due to an accompanying/evolving (coincidental) Alzheimer's disease process or, as in a single case, Dementia with Lewy bodies, within the cerebral cortex rather than as a result of TDP-43 proteinopathy. Conversely, in FTD and FTD + MND dementia is more likely to be associated with TDP-43 proteinopathy than tau. Hence, present study shows no progression in severity of (tau) pathology from MND through FTD + MND to FTD, and does not support the concept of these conditions forming a continuum of clinical or pathological change.
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Córtex Cerebral/metabolismo , Proteínas de Ligação a DNA/metabolismo , Degeneração Lobar Frontotemporal/patologia , Doença dos Neurônios Motores/patologia , Proteínas tau/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Amiloide/metabolismo , Apolipoproteínas E/genética , Feminino , Degeneração Lobar Frontotemporal/genética , Degeneração Lobar Frontotemporal/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Doença dos Neurônios Motores/genética , Doença dos Neurônios Motores/metabolismo , Fosforilação , Isoformas de Proteínas/metabolismoRESUMO
Intracellular filamentous tau pathology is the defining feature of tauopathies, which form a subset of neurodegenerative diseases. We have analyzed pathological tau in Alzheimer's disease, and in frontotemporal lobar degeneration associated with tauopathy to include cases with Pick bodies, corticobasal degeneration, progressive supranuclear palsy, and ones due to intronic mutations in MAPT. We found that the C-terminal band pattern of the pathological tau species is distinct for each disease. Immunoblot analysis of trypsin-resistant tau indicated that the different band patterns of the 7-18 kDa fragments in these diseases likely reflect different conformations of tau molecular species. Protein sequence and mass spectrometric analyses revealed the carboxyl-terminal region (residues 243-406) of tau comprises the protease-resistant core units of the tau aggregates, and the sequence lengths and precise regions involved are different among the diseases. These unique assembled tau cores may be used to classify and diagnose disease strains. Based on these results, we propose a new clinicopathological classification of tauopathies based on the biochemical properties of tau.
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Química Encefálica , Immunoblotting/métodos , Espectrometria de Massas/métodos , Análise de Sequência de Proteína/métodos , Tauopatias/classificação , Tauopatias/metabolismo , Proteínas tau/química , Idoso , Idoso de 80 Anos ou mais , Sequência de Aminoácidos , Encéfalo/ultraestrutura , Feminino , Humanos , Masculino , Microscopia Imunoeletrônica/métodos , Pessoa de Meia-Idade , Conformação Proteica , Sarcosina/análogos & derivados , Sarcosina/metabolismo , Tauopatias/patologia , Tripsina/metabolismo , Proteínas tau/metabolismoAssuntos
Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Emaranhados Neurofibrilares/metabolismo , Emaranhados Neurofibrilares/patologia , Proteínas tau/metabolismo , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Cadáver , Endopeptidase K/farmacologia , Epitopos , Humanos , Isoformas de Proteínas/metabolismoRESUMO
Gene-targeting technology using mouse embryonic stem (ES) cells has become the "gold standard" for analyzing gene functions and producing disease models. Recently, genetically modified mice with multiple mutations have increasingly been produced to study the interaction between proteins and polygenic diseases. However, introduction of an additional mutation into mice already harboring several mutations by conventional natural crossbreeding is an extremely time- and labor-intensive process. Moreover, to do so in mice with a complex genetic background, several years may be required if the genetic background is to be retained. Establishing ES cells from multiple-mutant mice, or disease-model mice with a complex genetic background, would offer a possible solution. Here, we report the establishment and characterization of novel ES cell lines from a mouse model of Alzheimer's disease (3xTg-AD mouse, Oddo et al. in Neuron 39:409-421, 2003) harboring 3 mutated genes (APPswe, TauP301L, and PS1M146V) and a complex genetic background. Thirty blastocysts were cultured and 15 stable ES cell lines (male: 11; female: 4) obtained. By injecting these ES cells into diploid or tetraploid blastocysts, we generated germline-competent chimeras. Subsequently, we confirmed that F1 mice derived from these animals showed similar biochemical and behavioral characteristics to the original 3xTg-AD mice. Furthermore, we introduced a gene-targeting vector into the ES cells and successfully obtained gene-targeted ES cells, which were then used to generate knockout mice for the targeted gene. These results suggest that the present methodology is effective for introducing an additional mutation into mice already harboring multiple mutated genes and/or a complex genetic background.
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Doença de Alzheimer/genética , Células-Tronco Embrionárias/fisiologia , Marcação de Genes/métodos , Camundongos Transgênicos , Peptídeos beta-Amiloides/genética , Animais , Blastocisto/fisiologia , Linhagem Celular , Modelos Animais de Doenças , Células Germinativas , Glicosilação , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação , Ratos , Tetraploidia , Proteínas tau/genéticaRESUMO
The deposition of amyloid-like filaments in the brain is the central event in the pathogenesis of neurodegenerative diseases. Here we report cellular models of intracytoplasmic inclusions of α-synuclein, generated by introducing nucleation seeds into SH-SY5Y cells with a transfection reagent. Upon introduction of preformed seeds into cells overexpressing α-synuclein, abundant, highly filamentous α-synuclein-positive inclusions, which are extensively phosphorylated and ubiquitinated and partially thioflavin-positive, were formed within the cells. SH-SY5Y cells that formed such inclusions underwent cell death, which was blocked by small molecular compounds that inhibit ß-sheet formation. Similar seed-dependent aggregation was observed in cells expressing four-repeat Tau by introducing four-repeat Tau fibrils but not three-repeat Tau fibrils or α-synuclein fibrils. No aggregate formation was observed in cells overexpressing three-repeat Tau upon treatment with four-repeat Tau fibrils. Our cellular models thus provide evidence of nucleation-dependent and protein-specific polymerization of intracellular amyloid-like proteins in cultured cells.
Assuntos
Corpos de Inclusão/metabolismo , Modelos Biológicos , Doenças Neurodegenerativas/metabolismo , alfa-Sinucleína/metabolismo , Proteínas tau/metabolismo , Morte Celular , Linhagem Celular Tumoral , Humanos , Corpos de Inclusão/genética , Doenças Neurodegenerativas/genética , Fosforilação , Estrutura Secundária de Proteína , alfa-Sinucleína/genética , Proteínas tau/genéticaRESUMO
The clinical inefficacy of many medications has served to highlight the need for deeper studies on the formulation components, processes used and physicochemical characteristics of drugs. The objective of this study was to evaluate the in vitro release of primaquine phosphate from tablets available in Brazil for treating malaria, and the development of new formulations for conventional release. Although the primaquine phosphate tablets studied had been approved according to the criteria proposed by the United States Pharmacopoeia (2006) for the dissolution test, they did not present adequate dissolution performance characteristics, in that there was drug retention during the release process. The results indicate the existence of problems in the primaquine phosphate tablets analyzed, and it may suggest that this is one of the factors responsible for the appearance of parasite resistance.
Assuntos
Antimaláricos/química , Primaquina/química , Antimaláricos/normas , Área Sob a Curva , Brasil , Varredura Diferencial de Calorimetria , Humanos , Malária/tratamento farmacológico , Primaquina/normas , Padrões de Referência , Solubilidade , Comprimidos/química , Comprimidos/normasRESUMO
A ineficácia clínica de muitos medicamentos tem servido de alerta para estudos mais profundos sobre os componentes da formulação, processos empregados e características físico-químicas dos fármacos. O objetivo deste trabalho foi avaliar a liberação in vitro de comprimidos de fosfato de primaquina disponíveis no Brasil para tratamento da malária, e o desenvolvimento de novas formulações de liberação convencional. Embora os comprimidos de fosfato de primaquina estudados tenham sido aprovados pelos critérios propostos pela Farmacopéia Americana (2006) para o teste de dissolução, não apresentaram desempenho adequado para o perfil de dissolução, mostrando retenção do fármaco durante a liberação. Os resultados indicam a existência de problemas nos comprimidos de fosfato de primaquina analisados, podendo sugerir como um dos fatores responsáveis pelo aparecimento de resistência dos parasitas.
The clinical inefficacy of many medications has served to highlight the need for deeper studies on the formulation components, processes used and physicochemical characteristics of drugs. The objective of this study was to evaluate the in vitro release of primaquine phosphate from tablets available in Brazil for treating malaria, and the development of new formulations for conventional release. Although the primaquine phosphate tablets studied had been approved according to the criteria proposed by the United States Pharmacopoeia (2006) for the dissolution test, they did not present adequate dissolution performance characteristics, in that there was drug retention during the release process. The results indicate the existence of problems in the primaquine phosphate tablets analyzed, and it may suggest that this is one of the factors responsible for the appearance of parasite resistance.
Assuntos
Humanos , Antimaláricos/química , Primaquina/química , Área Sob a Curva , Antimaláricos/normas , Brasil , Varredura Diferencial de Calorimetria , Malária/tratamento farmacológico , Primaquina/normas , Padrões de Referência , Solubilidade , Comprimidos/química , Comprimidos/normasRESUMO
Disulfide functionalized hairpin-forming DNAs having an anthraquinone linker as a redox probe with variable number of A-T base pairs were synthesized. The electron transfer through the DNAs in self-assembled monolayers on gold surface was studied.
Assuntos
Antraquinonas/química , Sondas de DNA/química , Ouro/química , Adenina/química , Sondas de DNA/síntese química , Eletroquímica , Eletrodos , Transporte de Elétrons , Oxirredução , Timina/químicaRESUMO
The dissolution profile for solid pharmaceutical forms containing chloramphenicol 250 mg available in Brazil was determined using a method from the American Pharmacopoeia (United States Pharmacopoeia, 2004) and then compared. Two different methods of dissolution profile comparison were used: ANOVA, and an independent model. Differences between the formulations were reflected in the dissolution profiles. The presence of metastable polymorphs or amorphous forms of chloramphenicol palmitate might be responsible for variations in the concentration of the drug observed within formulations.
O perfil de dissolução de formas farmacêuticas sólidas contendo palmitato de cloranfenicol 250 mg disponíveis no Brasil foi determinada pelo método da Farmacopéia Americana (United States Pharmacopeia, 2004) e comparado. Duas categorias de métodos para comparação dos perfis de dissolução foram utilizadas: ANOVA e modelo independente. Diferenças entre as formulações foram refletidas nos perfis de dissolução. A presença de polimorfos metaestáveis ou formas amorfas de palmitato de cloranfenicol pode ser responsável pelas variações na concentração do fármaco observada nas formulações.