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1.
Cell Death Differ ; 19(10): 1677-88, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22539004

RESUMO

Cerebral ischemia and excitotoxic injury induce transient or permanent bioenergetic failure, and may result in neuronal apoptosis or necrosis. We have previously shown that ATP depletion and activation of AMP-activated protein kinase (AMPK) during excitotoxic injury induces neuronal apoptosis by transcription of the pro-apoptotic BH3-only protein, Bim. AMPK, however, also exerts pro-survival functions in neurons. The molecular switches that determine these differential outcomes are not well understood. Using an approach combining biochemistry, single-cell imaging and computational modeling, we here demonstrate that excitotoxic injury activated the bim promoter in a FOXO3-dependent manner. The activation of AMPK reduced AKT activation, and led to dephosphorylation and nuclear translocation of FOXO3. Subsequent mutation studies indicated that bim gene activation during excitotoxic injury required direct FOXO3 phosphorylation by AMPK in the nucleus as a second activation step. Inhibition of this phosphorylation prevented Bim expression and protected neurons against excitotoxic and oxygen/glucose deprivation-induced injury. Systems analysis and computational modeling revealed that these two activation steps defined a coherent feed-forward loop; a network motif capable of filtering any effects of short-term AMPK activation on bim gene induction. This may prevent unwanted AMPK-mediated Bim expression and apoptosis during transient or physiological bioenergetic stress.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Proteínas Quinases Ativadas por AMP/antagonistas & inibidores , Proteínas Quinases Ativadas por AMP/genética , Animais , Apoptose , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Proteína 11 Semelhante a Bcl-2 , Núcleo Celular/metabolismo , Células Cultivadas , Regulação para Baixo , Proteína Forkhead Box O3 , Glucose/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Neurônios/citologia , Neurônios/metabolismo , Fosforilação , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Ratos , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Fator de Transcrição AP-1/metabolismo
2.
Cell Death Differ ; 17(3): 459-68, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19779495

RESUMO

Prolonged seizures (status epilepticus) are associated with brain region-specific regulation of apoptosis-associated signaling pathways. Bcl-2 homology domain 3-only (BH3) members of the Bcl-2 gene family are of interest as possible initiators of mitochondrial dysfunction and release of apoptogenic molecules after seizures. Previously, we showed that expression of the BH3-only protein, Bcl-2 interacting mediator of cell death (Bim), increased in the rat hippocampus but not in the neocortex after focal-onset status epilepticus. In this study, we examined Bim expression in mice and compared seizure damage between wild-type and Bim-deficient animals. Status epilepticus induced by intra-amygdala kainic acid (KA) caused extensive neuronal death within the ipsilateral hippocampal CA3 region. Hippocampal activation of factors associated with transcriptional and posttranslational activation of Bim, such as CHOP and c-Jun NH(2)-terminal kinases, was significant within 1 h. Upregulation of bim mRNA was evident after 2 h and Bim protein increased between 4 and 24 h. Hippocampal CA3 neurodegeneration was reduced in Bim-deficient mice compared with wild-type animals after seizures in vivo, and short interfering RNA molecules targeting bim reduced cell death after KA treatment of hippocampal organotypic cultures. In contrast, neocortical Bim expression declined after status epilepticus, and neocortex damage in Bim-deficient mice was comparable with that in wild-type animals. These results show region-specific differential contributions of Bim to seizure-induced neuronal death.


Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Hipocampo/metabolismo , Proteínas de Membrana/metabolismo , Neocórtex/metabolismo , Fármacos Neuroprotetores/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Estado Epiléptico/metabolismo , Animais , Antracenos/metabolismo , Proteínas Reguladoras de Apoptose/genética , Proteína 11 Semelhante a Bcl-2 , Hipocampo/citologia , Hipocampo/patologia , Proteínas Quinases JNK Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases JNK Ativadas por Mitógeno/genética , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Ácido Caínico/farmacologia , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neocórtex/citologia , Proteínas Proto-Oncogênicas/genética , Ratos , Estado Epiléptico/induzido quimicamente , Fator de Transcrição CHOP/genética , Fator de Transcrição CHOP/metabolismo
3.
Behav Brain Res ; 188(1): 209-18, 2008 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-18160143

RESUMO

Developmental exposure to alcohol can produce characteristic physiological and cognitive deficits, often termed Fetal Alcohol Spectrum Disorder (FASD). More recently, social deficits have been shown to occur both in FASD and animal models of FASD; the behavioral and neural bases of these deficits remain to be determined. It was hypothesized that changes in sensory processing may in part underlie the social deficits seen in FASD. This study used a rat model of FASD and social play, a behavior critical to adult social functioning, to begin to examine this hypothesis. Somatosensory cues from dorsal contact to the nape of the neck, critical to the initiation of pinning, were systematically degraded by administration of different doses of xylocaine, a topical anesthetic. Neuronal activity after 1h of play was assessed by measurement of c-Fos immunoreactivity (IR) in different brain regions. Ethanol-exposed rats showed an increased frequency of pinning during social play and were more sensitive to the degradation of somatosensory cues compared to the control groups, suggesting difficulties in processing somatosensory cues. Neuronal activity in the somatosensory cortex induced by play was significantly decreased in the ethanol-exposed group compared to the non-treated group. The c-Fos IR in the nucleus accumbens was altered in a sexually dimorphic manner in the ethanol-exposed group. Thus, the behavioral and brain measures are consistent with the hypothesis that ethanol exposure during development induces alterations in social play via deficits in processing somatosensory cues that are important to social play.


Assuntos
Encéfalo/metabolismo , Transtornos do Espectro Alcoólico Fetal/psicologia , Jogos e Brinquedos/psicologia , Efeitos Tardios da Exposição Pré-Natal , Proteínas Proto-Oncogênicas c-fos/metabolismo , Análise de Variância , Anestésicos Locais/farmacologia , Animais , Encéfalo/efeitos dos fármacos , Feminino , Transtornos do Espectro Alcoólico Fetal/metabolismo , Lidocaína/farmacologia , Masculino , Gravidez , Propriocepção/efeitos dos fármacos , Propriocepção/fisiologia , Ratos , Comportamento Social , Percepção Social , Tato/efeitos dos fármacos , Tato/fisiologia
4.
J Clin Pharmacol ; 42(2): 166-74, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11831539

RESUMO

A phase I clinical trial was conducted to assess thefeasibility of a more convenient and safe dosing regime for the cytoprotective drug amifostine. Two alternative routes of administration, oral and subcutaneous (s.q.), each with a dose of 500 mg, were compared to a 7.5-minute intravenous (i.v.) infusion, with a dose of 200 mg/m2, in normal, healthy volunteers (N = 12). Bioavailability of amifostine (parent drug) and its pharmacologically active metabolite, WR-1065, was evaluated by comparing the area under the concentration-time curve (AUC) derived from HPLC analysis of amifostine and both protein-free and protein-bound WR-1065 in all three routes of administration. Results showed that SQ (but not oral) administration of amifostine could provide a more effective dosing regimen, in terms of both a reasonable AUC for the bound form of WR-1065 and decreased toxicity, compared to i.v. delivery. These data suggest that the protein-bound form of WR-1065 plays an important role in contributing to the bioavailability of this clinically useful cytoprotective drug.


Assuntos
Amifostina/administração & dosagem , Amifostina/farmacocinética , Protetores contra Radiação/administração & dosagem , Protetores contra Radiação/farmacocinética , Administração Oral , Adolescente , Adulto , Amifostina/efeitos adversos , Área Sob a Curva , Disponibilidade Biológica , Estudos Cross-Over , Método Duplo-Cego , Meia-Vida , Humanos , Infusões Intravenosas , Injeções Subcutâneas , Masculino , Projetos Piloto , Ligação Proteica , Protetores contra Radiação/efeitos adversos
5.
J Acquir Immune Defic Syndr ; 28(5): 422-8, 2001 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-11744829

RESUMO

The effect of highly active antiretroviral therapy (HAART) on the natural history of anal squamous intraepithelial lesions (ASIL)-the likely anal cancer precursor-and anal human papillomavirus (HPV) infection is unknown. ASIL severity and level of anal HPV DNA were evaluated among HIV-positive men who have sex with men (MSM) for at least 6 months before initiation of HAART. The results were compared with those from a 6-month period after initiation of HAART. Anal swabs for cytology and HPV studies were obtained, followed by high-resolution anoscopy and biopsy. Among men whose most severe pre-HAART diagnosis was atypical squamous cells of undetermined significance or low-grade ASIL, 18% (confidence interval [CI], 6-31%, 7 of 38) progressed and 21% (CI, 8-34%, 8 of 38) regressed 6 months after starting HAART. Seventeen percent (CI, 0-38%, 2 of 12) of study subjects who began with a normal diagnosis developed ASIL. Only 4% (CI, 0-10%, 1 of 28) of study subjects with high-grade ASIL regressed to normal. There was no reduction in the proportion of study subjects who tested positive for HPV DNA or HPV DNA levels after HAART initiation. The ASIL and HPV data were similar to those of the pre-HAART comparison period. These results indicate that HAART has little effect on either ASIL or HPV in the first 6 months after HAART initiation.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Neoplasias do Ânus/tratamento farmacológico , Neoplasias de Células Escamosas/tratamento farmacológico , Papillomaviridae , Infecções por Papillomavirus/tratamento farmacológico , Adulto , Idoso , Canal Anal/patologia , Canal Anal/virologia , Terapia Antirretroviral de Alta Atividade , Neoplasias do Ânus/patologia , Estudos de Coortes , Homossexualidade Masculina , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias de Células Escamosas/patologia , Infecções por Papillomavirus/patologia
6.
J Chromatogr B Biomed Sci Appl ; 739(2): 357-62, 2000 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-10755379

RESUMO

A high-performance liquid chromatographic method for automated analysis of both protein-bound and total S-2-(3-aminopropylamino)ethanethiol (WR-1065) in blood has been developed in our laboratory. WR-1065 is the active thiol metabolite of the radio- and chemo-protector drug amifostine (WR-2721). Using WR-1065 quality control levels over the experimental range: 7.0, 45.0 and 85.0 micromol/l spiked into plasma, method validation for total WR-1065 included between-run assessment of imprecision (SD/C.V.%: 1.11/16.7%, 6.58/15.5% and 9.24/11.3%, respectively) and % accuracy (94.7, 106.0 and 97.2%).


Assuntos
Proteínas Sanguíneas/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Mercaptoetilaminas/sangue , Protetores contra Radiação/metabolismo , Amifostina/metabolismo , Humanos , Ligação Proteica , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrometria de Fluorescência
7.
Am J Physiol ; 277(1): G127-36, 1999 07.
Artigo em Inglês | MEDLINE | ID: mdl-10409159

RESUMO

Voltage-activated K(+) (K(V)) channels play an important role in regulating the membrane potential in excitable cells. In gastrointestinal (GI) smooth muscles, these channels are particularly important in modulating spontaneous electrical activities. The purpose of this study was to identify the molecular components that may be responsible for the K(V) currents found in the canine GI tract. In this report, we have examined the qualitative expression of eighteen different K(V) channel genes in canine GI smooth muscle cells at the transcriptional level using RT-PCR analysis. Our results demonstrate the expression of K(V)1.4, K(V)1.5, K(V)1.6, K(V)2.2, and K(V)4.3 transcripts in all regions of the GI tract examined. Transcripts encoding K(V)1.2, K(V)beta1.1, and K(V)beta1.2 subunits were differentially expressed. K(V)1.1, K(V)1.3, K(V)2.1, K(V)3.1, K(V)3.2, K(V)3.4, K(V)4.1, K(V)4.2, and K(V)beta2.1 transcripts were not detected in any GI smooth muscle cells. We have also determined the protein expression for a subset of these K(V) channel subunits using specific antibodies by immunoblotting and immunohistochemistry. Immunoblotting and immunohistochemistry demonstrated that K(V)1.2, K(V)1.4, K(V)1.5, and K(V)2.2 are expressed at the protein level in GI tissues and smooth muscle cells. K(V)2.1 was not detected in any regions of the GI tract examined. These results suggest that the wide array of electrical activity found in different regions of the canine GI tract may be due in part to the differential expression of K(V) channel subunits.


Assuntos
Sistema Digestório/metabolismo , Músculo Liso/metabolismo , Canais de Potássio/química , Canais de Potássio/metabolismo , Animais , DNA Complementar/metabolismo , Cães , Immunoblotting , Imuno-Histoquímica , Canais de Potássio/genética , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Mensageiro/metabolismo
8.
Semin Oncol ; 26(2 Suppl 7): 34-6, 1999 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10348258

RESUMO

Findings of pharmacokinetic studies of amifostine (Ethyol; Alza Pharmaceuticals, Palo Alto, CA/US Bioscience, West Conshohocken, PA) in animal models and in human cancer patients support the hypothesis that amifostine pharmacokinetics are nonlinear. The nonlinear pharmacokinetic behavior of amifostine suggests that administration of doses higher than 740 mg/m2 does not increase the amount of drug available due to urinary excretion of the excess parent drug and its metabolites. Although the intravenous formulation of amifostine is the only one currently used in the treatment of cancer patients, there is growing interest in the investigation of subcutaneous administration as a practical alternative. A pilot pharmacokinetic evaluation of subcutaneous administration of amifostine in 12 healthy male volunteers compared the relative bioavailability of 500 mg of amifostine administered subcutaneously with that of 200 mg/m2 given intravenously.


Assuntos
Amifostina/farmacocinética , Citoproteção , Substâncias Protetoras/farmacocinética , Administração Oral , Amifostina/administração & dosagem , Área Sob a Curva , Disponibilidade Biológica , Humanos , Injeções Intravenosas , Injeções Subcutâneas , Masculino , Projetos Piloto , Substâncias Protetoras/administração & dosagem
9.
J Physiol ; 515 ( Pt 2): 475-87, 1999 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-10050014

RESUMO

1. We used intracellular microelectrodes to record the membrane potential (Vm) of intact murine colonic smooth muscle. Electrical activity consisted of spike complexes separated by quiescent periods (Vm approximately -60 mV). The spike complexes consisted of about a dozen action potentials of approximately 30 mV amplitude. Tetraethylammonium (TEA, 1-10 mM) had little effect on the quiescent periods but increased the amplitude of the action potential spikes. 4-Aminopyridine (4-AP, >= 5 mM) caused continuous spiking. 2. Voltage clamp of isolated myocytes identified delayed rectifier K+ currents that activated rapidly (time to half-maximum current, 11.5 ms at 0 mV) and inactivated in two phases (tauf = 96 ms, taus = 1.5 s at 0 mV). The half-activation voltage of the permeability was -27 mV, with significant activation at -50 mV. 3. TEA (10 mM) reduced the outward current at potentials positive to 0 mV. 4-AP (5 mM) reduced the early current but increased outward current at later times (100-500 ms) consistent with block of resting channels relieved by depolarization. 4-AP inhibited outward current at potentials negative to -20 mV, potentials where TEA had no effect. 4. Qualitative PCR amplification of mRNA identified transcripts encoding delayed rectifier K+ channel subunits Kv1.6, Kv4.1, Kv4.2, Kv4.3 and the Kvbeta1.1 subunit in murine colon myocytes. mRNA encoding Kv 1.4 was not detected. 5. We find that TEA-sensitive delayed rectifier currents are important determinants of action potential amplitude but not rhythmicity. Delayed rectifier currents sensitive to 4-AP are important determinants of rhythmicity but not action potential amplitude.


Assuntos
Colo/fisiologia , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Canais de Potássio/fisiologia , 4-Aminopiridina/farmacologia , Animais , Separação Celular , Colo/citologia , Canais de Potássio de Retificação Tardia , Condutividade Elétrica , Expressão Gênica/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , Músculo Liso/citologia , Músculo Liso/fisiologia , Canais de Potássio/genética , Tetraetilamônio/farmacologia
10.
Am J Clin Oncol ; 21(6): 548-52, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9856653

RESUMO

A phase II study was conducted to evaluate the activity and toxicity of 96-hour infusional paclitaxel in patients with previously untreated metastatic colorectal cancer. Twelve patients were enrolled in this study. The first patient received a total dose of 140 mg/m2 over 96 hours resulting in grade 4 neutropenia, neutropenic fever, and grade 3 stomatitis. Subsequent patients received a total dose of 120 mg/m2 over 96 hours. Grade 3 to 4 neutropenia occurred in four of these patients. No significant thrombocytopenia was observed. Grade 3 to 4 nonhematologic toxicities in the group treated at 120 mg/m2 over 96 hours included nausea/vomiting in one patient, stomatitis in one patient, and diarrhea in two patients. One patient experienced a possible pulmonary hypersensitivity reaction. None of the 12 patients achieved an objective response. Two patients had stable disease and ten had progressive disease. Pharmacokinetic parameters including maximum plasma concentration and area under the concentration time curve were significantly higher in patients with grade 3 to 4 neutropenia than patients who experienced less toxicity. The authors conclude that further study of 96-hour infusional paclitaxel in patients with metastatic colorectal carcinoma is not warranted.


Assuntos
Antineoplásicos Fitogênicos/farmacocinética , Antineoplásicos Fitogênicos/uso terapêutico , Neoplasias Colorretais/tratamento farmacológico , Paclitaxel/farmacocinética , Paclitaxel/uso terapêutico , Idoso , Antineoplásicos Fitogênicos/administração & dosagem , Neoplasias Colorretais/patologia , Feminino , Humanos , Infusões Intravenosas , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica , Neutropenia , Paclitaxel/administração & dosagem
11.
Stroke ; 29(3): 660-7, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9506609

RESUMO

BACKGROUND AND PURPOSE: High-intensity transient signals (HITS) during cardiac surgery are capable of causing encephalopathy and cognitive deficits. This study was undertaken to determine whether intraoperative HITS cause alterations of neuropsychological function (NPF) and/or cerebral glucose metabolism (CMRGlc), even in a low-risk patient group, and whether induced changes are interrelated. METHODS: Eighteen patients without signs of cerebrovascular disease underwent elective coronary artery bypass grafting (CABG), and two of these additionally underwent valve replacement in normothermia. Intraoperatively, HITS were recorded by means of transcranial Doppler ultrasonography (TCD). Perioperatively, NPF and CMRGlc were assessed using a standardized complex test battery and positron emission tomography with 18F-2-fluoro-2-deoxy-D-glucose (FDG-PET), respectively. RESULTS: Intraoperatively, the number of HITS ranged from 90 to 1710 per patient and hemisphere, more on the right side than on the left (P<.05). HITS occurred primarily during cardiopulmonary bypass (71.3%) and, to a lesser extent, during aortic manipulation (22.2%). Changes in global and regional CMRGlc between first (one day preoperatively) and second (8 to 12 days postoperatively) FDG-PET scans were mild. No correlations were found between the number of HITS, age of patient, duration of cardiac ischemia or cardiopulmonary bypass and the changes in CMRGlc. In patients with recorded HITS and a postoperative decrease of regional CMRGlc (n=11), the maximal decrease of rCMR Glc in each hemisphere below the individual global change of CMRGlc correlated with the number of HITS (r= -0.46, P<.05). Limitations in NPF occurred 8 to 12 days postoperatively, resolved within 3 months, and were not found to be correlated to the absolute number of HITS or changes in CMRGlc. CONCLUSIONS: HITS during cardiac surgery can cause alterations of both NPF and CMRGlc, even in a low-risk patient group. However, the number of HITS and changes in NPF and CMRGlc are not necessarily interrelated, which indicates that (1) the location of brain damage related to HITS is more important for the development of NPF than is the absolute number of HITS, and (2) factors in addition to HITS might contribute to surgery-related brain damage.


Assuntos
Encefalopatias/etiologia , Encéfalo/irrigação sanguínea , Circulação Cerebrovascular , Ponte de Artéria Coronária/efeitos adversos , Glucose/metabolismo , Embolia e Trombose Intracraniana/diagnóstico , Adulto , Idoso , Encéfalo/metabolismo , Encefalopatias/diagnóstico , Cognição , Humanos , Memória , Pessoa de Meia-Idade , Testes Neuropsicológicos , Personalidade , Ultrassonografia Doppler
13.
Arch Neurol ; 54(2): 145-50, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9041855

RESUMO

BACKGROUND: Concepts of basal ganglia organization suggest structually and functionally segregated pathways that link putamen and caudate function to motor and cognitive performance, respectively. OBJECTIVE: To investigate whether motor and cognitive impairment in Parkinson disease is attributable to selective disturbance in nigrostriatal, dopaminergic function and regional cerebral glucose metabolism. DESIGN: Twenty patients with probable Parkinson disease underwent positron emission tomographic measurements of dopaminergic, nigrostriatal function (positron emission tomography with fluorodopa F 18), regional glucose metabolism (positron emission tomography with fludeoxyglucose F 18), memory testing, and evaluation of locomotor disability. RESULTS: Memory performance in the patient cohort strongly correlated with the individual disease duration and degree of locomotor disability (P < .05). Striatal uptake rates of fluorodopa F 18 were significantly reduced in all patients (P < .05) compared with those in normal control subjects, and putaminal rates correlated significantly with the patients' degree of locomotor disability (P < .01) but not with memory performance. In the patients with an advanced stage of disease, there was a significant correlation between reduced caudate uptake rates of fluorodopa F 18 and the patients' impairment in delayed recall performance of the memory task (P < .05) but not with the individual degree of locomotor disability. No changes were found for regional glucose metabolic rates in the patients compared with the controls. CONCLUSIONS: The present study provides evidence for the hypothesis that on the level of the striatum, motor impairment in Parkinson disease may be assigned to altered dopamine neuronal integrity in the putamen but not in the caudate, whereas memory impairment in the more advanced cases may be attributed to caudate but not putaminal dysfunction.


Assuntos
Gânglios da Base/fisiopatologia , Memória , Movimento , Doença de Parkinson/fisiopatologia , Idoso , Gânglios da Base/diagnóstico por imagem , Gânglios da Base/metabolismo , Corpo Estriado/fisiopatologia , Desoxiglucose/análogos & derivados , Feminino , Fluordesoxiglucose F18 , Glucose/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/metabolismo , Cintilografia
14.
Semin Oncol ; 23(4 Suppl 8): 18-22, 1996 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8783662

RESUMO

This article reviews the chemistry, measurement, metabolism, and pharmacokinetics of the cytoprotective agent amifostine. Validated analytic methodology to measure parent drug and pharmacologically active metabolites and pharmacokinetic studies are essential to the efficient performance and analysis of clinical studies. Well-validated analytic methods developed in the authors' laboratory were used to characterize this agent. Amifostine [s-2-(3-aminopropylamino)ethyl-phosphorothioate] is the phosphorylated pro-drug form of the active free thiol drug WR-1065 [2-(3-aminopropylamino)ethanethiol]. Observations described here support the hypothesis that amifostine is dephosphorylated rapidly by alkaline phosphatase present on the plasma membranes of the arteriolar endothelium of various normal tissues and on the plasma membranes of the kidneys' proximal tubular epithelium to its active thiol metabolite WR-1065, which in turn immediately enters normal tissues. Other metabolites that have been identified are WR-33278, the symmetrical disulfide of WR-1065; the mixed disulfides WR-1065-cysteine and WR-1065-glutathione; and cysteamine. Amifostine was recently approved by the US Food and Drug Administration for use as a cytoprotector in cancer patients receiving chemotherapy. Current pharmacokinetic studies in cancer patients are focusing on establishing a population model as a basis for developing limited sampling strategies for future investigations of the pharmacokinetic-pharmacodynamic behavior of amifostine.


Assuntos
Amifostina/farmacocinética , Protetores contra Radiação/farmacocinética , Amifostina/análise , Amifostina/química , Amifostina/metabolismo , Animais , Humanos , Mercaptoetilaminas/análise , Protetores contra Radiação/análise , Protetores contra Radiação/química , Protetores contra Radiação/metabolismo
15.
Radiat Res ; 143(1): 107-10, 1995 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7597137

RESUMO

Rectal wall injury is an important treatment-related morbidity in patients treated with radiation for prostate cancer. We have undertaken this study to investigate the merits of topical intrarectal application of the radioprotective compound WR-2721. Male Copenhagen rats were injected intrarectally with 2% WR-2721 gel. At 10, 20, 30 and 40 min after application, a laparotomy was performed, and the rectum and prostate were removed. Concentrations of total WR-1065 (the active metabolite of WR-2721) were determined in these samples by an HPLC assay. While the concentration in the rectal wall tended to increase with time, it did not change substantially in the prostate. The concentration in the rectal wall was found to be significantly higher at all times. We conclude that preferential accumulation of WR-2721 in the rectal wall can be achieved by topical application. This is a promising approach to modifying rectal wall tolerance that deserves more study.


Assuntos
Amifostina/farmacocinética , Neoplasias da Próstata/radioterapia , Reto/metabolismo , Administração Tópica , Amifostina/administração & dosagem , Amifostina/uso terapêutico , Animais , Cromatografia Líquida de Alta Pressão , Masculino , Próstata/metabolismo , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/metabolismo , Ratos
16.
Drug Metab Dispos ; 22(6): 895-902, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-7895607

RESUMO

This study investigated the metabolism of the radio- and chemoprotector compound, WR-2721 [amifostine; s-2-(3- aminopropylamino)ethylphosphorothioate], in the Balb/c mouse. The latter was selected for these studies because considerable radiation protection data have been published for this mouse strain using the WR-2721 dose, route of administration, and optimal time for protection following intraperitoneal injection used herein. It is known that protection requires conversion of the parent drug to its free thiol metabolite, WR-1065, in cultured cells. Because it is possible that metabolites of WR-1065 could be involved in protection and because thiols are metabolically very reactive molecules, we investigated the metabolism of WR-2721 using electrochemical detection-HPLC methods. The following are the major findings in this study: 1) WR-2721 drug was rapidly cleared from the bloodstream. Blood concentration of the parent drug decreased 10-fold 30 min after administration from the maximal observed value at 5 min 2) WR-1065 rapidly appeared in the perchloric acid (PCA)-soluble fraction of normal solid tissues. The highest WR-1065 concentrations in liver and kidney were 965 and 2195 mumol/kg, respectively, 10 min after parent drug administration, whereas for heart and small intestine the highest values were 739 and 410 mumol/kg at 30 min. 3) WR-1065 accumulated in the PCA-soluble fraction of two experimental tumors at a lower rate than for the other tissues.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Amifostina/metabolismo , Amifostina/farmacologia , Animais , Cisteamina/análise , Cisteamina/metabolismo , Dissulfetos/metabolismo , Glutationa/análise , Glutationa/metabolismo , Masculino , Mercaptoetilaminas/metabolismo , Camundongos , Camundongos Endogâmicos BALB C
17.
Blood ; 83(11): 3132-7, 1994 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-8193351

RESUMO

4-Hydroperoxycyclophosphamide (4-HC), a commonly used marrow-purging agent, is active against many tumors, but is also toxic to normal marrow progenitors. Amifostine (WR-2721) is a sulfhydryl compound with chemoprotectant activity. Preclinical studies using suspensions of bone marrow and breast cancer cells demonstrated that ex vivo treatment with amifostine followed by 4-HC resulted in protection of marrow progenitors, with no compromise in the antitumor effect of 4-HC. This fact stimulated the development of a clinical trial. Bone marrow was harvested from 15 poor-prognosis breast cancer patients and randomly assigned to ex vivo treatment with amifostine followed by 4-HC (amifostine + 4-HC), or treatment with 4-HC alone. High-dose chemotherapy was then administered followed by infusion of the purged autologous bone marrow support (ABMS). Leukocyte engraftment, defined as a white blood cell count > or = 1 x 10(9)/L, was achieved in an average of 26 days for patients whose marrow was purged with amifostine + 4-HC versus 36 days for patients whose marrow was purged with 4-HC alone (P = .032). The average number of platelet transfusions (12 v 29; P = .017) and days of antibiotic therapy (28 v 40; P = .012) were significantly less for patients whose marrow was exposed to amifostine + 4-HC, compared with 4-HC alone. Unpurged backup marrow fractions were infused into three patients whose marrow was purged with 4-HC alone, because of inadequate marrow recovery. None of the patients who received amifostine + 4-HC-purged marrow required a backup marrow fraction. Complete remissions were achieved in 83% of patients with measurable disease, with no difference between the two cohorts. Forty-three percent of patients remained alive and progression-free at a mean of 13 months posttransplant. There was no significant difference in the rate or pattern of relapse for patients whose marrow was purged with amifostine + 4-HC compared with those whose marrow was purged with 4-HC alone. Ex vivo treatment of marrow with amifostine significantly shortens the time to marrow recovery, thereby reducing the risk of myelosuppressive complications in breast cancer patients receiving high-dose chemotherapy and 4-HC-purged ABMS. Since supportive care requirements are also significantly decreased, amifostine may reduce the cost of such therapy.


Assuntos
Amifostina/farmacologia , Purging da Medula Óssea , Transplante de Medula Óssea , Neoplasias da Mama/terapia , Ciclofosfamida/análogos & derivados , Adulto , Terapia Combinada , Ciclofosfamida/farmacologia , Feminino , Células-Tronco Hematopoéticas , Humanos , Transplante Autólogo
18.
Ther Drug Monit ; 15(6): 483-7, 1993 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8122281

RESUMO

The need for well-designed pharmacokinetic (PK) and pharmacodynamic (PD) studies early in the development of new drugs is described. In this review we illustrate the application and cost-effectiveness of optimal sampling theory in PK study design for ongoing clinical trial studies of ethyol, a chemoprotector drug. The importance of careful selection of the appropriate biological fluid in which to measure drug concentration at the earliest possible stage of new drug development is described in the context of the development of new immunosuppressive drugs. We focus on the requirement for well-validated analytical methodology in PK-PD studies, described in a discussion of the analytical methodology in use in clinical trials of two immunosuppressive agents, cyclosporin G and RS-61443 (mycophenolate mofetil).


Assuntos
Ensaios Clínicos como Assunto , Monitoramento de Medicamentos/métodos , Preparações Farmacêuticas/análise , Ensaios Clínicos como Assunto/economia , Análise Custo-Benefício , Monitoramento de Medicamentos/economia , Humanos , Imunossupressores/farmacocinética , Imunossupressores/farmacologia , Farmacologia Clínica , Projetos de Pesquisa
19.
Int J Radiat Oncol Biol Phys ; 23(1): 9-17, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1572835

RESUMO

Between 1983 and 1987 the Radiation Therapy Oncology Group conducted a prospective phase II study to evaluate survival in primary non-Hodgkin's lymphoma of the brain treated with whole brain irradiation to 40 Gy and a 20 Gy boost to tumor plus a 2 cm margin. Forty-one patients are reported. Full follow-up is available on 35/41 who have died. Six are alive at 8.8-67.2 months from start of radiation therapy with a median followup of 53.9 months. Overall median survival was 11.6 months from start of radiation therapy and 12.2 months from diagnosis, with 48% surviving 1 year and 28% surviving 2 years. Karnofsky Performance Status and age were significant prognostic factors. Patients with a Karnofsky Performance Status of 70-100 had a median survival of 21.1 months compared to 5.6 months for patients with a status of 40-60 (p less than .001). Fourteen patients less than 60 years of age had a median survival of 23.1 months, while 27 patients greater than or equal to 60 years of age had a median survival of 7.6 months (log-rank p = .001). Disease recurred in the brain in 25/41 (61%) of the patients, (21/41 in the brain only and 4/41 in the brain plus distant metastases). Despite high dose and large volume irradiation, primary Central Nervous System lymphoma still exhibits excessive mortality, especially in older patients. This paradox of the relative radioresistance of primary Central Nervous System lymphoma remains unresolved.


Assuntos
Neoplasias Encefálicas/radioterapia , Linfoma não Hodgkin/radioterapia , Adulto , Antineoplásicos/administração & dosagem , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/epidemiologia , Terapia Combinada , Feminino , Humanos , Linfoma não Hodgkin/tratamento farmacológico , Linfoma não Hodgkin/epidemiologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Radioterapia de Alta Energia , Análise de Sobrevida
20.
J Clin Oncol ; 9(5): 770-6, 1991 May.
Artigo em Inglês | MEDLINE | ID: mdl-2016618

RESUMO

The Eastern Cooperative Oncology Group (ECOG) conducted a study in which patients with advanced chronic lymphocytic leukemia (CLL) were randomized between a regimen consisting of chlorambucil (30 mg/m2 orally day 1) and prednisone (80 mg orally days 1 to 5) (C + P) administered every 2 weeks and a more intensive regimen of cyclosphosphamide (300 mg/m2 orally days 1 to 5), vincristine (1.4 mg/m2 intravenously [IV] day 1), and prednisone (100 mg/m2 orally days 1 to 5) (CVP) given every 3 weeks. Treatment was continued for up to 18 months to maximal response. Of the 122 eligible patients, 60 received C + P, while 62 received CVP. With a median follow-up of 7 years, there were no significant differences in survival (4.8 v 3.9 years, P = .12), complete remission (CR) rate (25% v 23%; P = .83), or duration of response (2.0 v 1.9 years; P = .78) between C + P and CVP. Toxicity was modest despite the prolonged treatment. The long median survival of 4.1 years for stage III and IV patients is superior to that usually reported. This could stem from continuing treatment to maximal response rather than an increase in intensity of therapy. These results are comparable to those reported with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) therapy by other investigators. The data suggest that intermittent C + P administered to maximal response continues to be the standard treatment approach for advanced CLL.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Adulto , Idoso , Clorambucila/administração & dosagem , Ciclofosfamida/administração & dosagem , Esquema de Medicação , Feminino , Seguimentos , Humanos , Leucemia Linfocítica Crônica de Células B/mortalidade , Masculino , Pessoa de Meia-Idade , Prednisona/administração & dosagem , Indução de Remissão , Análise de Sobrevida , Vincristina/administração & dosagem
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