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1.
Clin Oncol (R Coll Radiol) ; 35(10): 630-639, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37507279

RESUMO

AIMS: Pneumonitis is a common and potentially deadly complication of combined chemoradiation and immune checkpoint inhibition (CRT-ICI) in patients with locally advanced non-small cell lung cancer (LA-NSCLC). In this study we sought to identify the risk factors for pneumonitis with CRT-ICI therapy in LA-NSCLC cases and determine its impact on survival. MATERIALS AND METHODS: We conducted a retrospective chart review of 140 patients with LA-NSCLC who underwent curative-intent CRT-ICI with durvalumab between 2018 and 2021. Pneumonitis was diagnosed by a multidisciplinary team of clinical experts. We used multivariable cause-specific hazard models to identify risk factors associated with grade ≥2 pneumonitis. We constructed multivariable Cox proportional hazard models to investigate the impact of pneumonitis on all-cause mortality. RESULTS: The median age of the cohort was 67 years; most patients were current or former smokers (86%). The cumulative incidence of grade ≥2 pneumonitis was 23%. Among survivors, 25/28 patients had persistent parenchymal scarring. In multivariable analyses, the mean lung dose (hazard ratio 1.14 per Gy, 95% confidence interval 1.03-1.25) and interstitial lung disease (hazard ratio 3.8, 95% confidence interval 1.3-11.0) increased the risk for pneumonitis. In adjusted models, grade ≥2 pneumonitis (hazard ratio 2.5, 95% confidence interval 1.0-6.2, P = 0.049) and high-grade (≥3) pneumonitis (hazard ratio 8.3, 95% confidence interval 3.0-23.0, P < 0.001) were associated with higher all-cause mortality. CONCLUSIONS: Risk factors for pneumonitis in LA-NSCLC patients undergoing CRT-ICI include the mean radiation dose to the lung and pre-treatment interstitial lung disease. Although most cases are not fatal, pneumonitis in this setting is associated with markedly increased mortality.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Pneumonia , Pneumonite por Radiação , Humanos , Idoso , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/radioterapia , Inibidores de Checkpoint Imunológico/uso terapêutico , Estudos Retrospectivos , Quimiorradioterapia/efeitos adversos , Pneumonia/etiologia , Pneumonia/complicações , Pneumonite por Radiação/epidemiologia , Pneumonite por Radiação/etiologia , Pneumonite por Radiação/tratamento farmacológico
2.
Behav Brain Res ; 356: 127-136, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30142394

RESUMO

There is a high prevalence of vitamin D deficiency and exposure to low levels of ethanol in pregnant women. However, there are a paucity of studies that have addressed the impact of both vitamin D deficiency and ethanol exposure on the offspring's vulnerability to neurodevelopmental disorders later in life. The aim of this study was to examine whether the absence of vitamin D during gestation in mice would alter the effects of prenatal exposure to low dose ethanol on the behaviour and dopaminergic gene expression patterns of juvenile mice. Four-week old female C57BL/6J mice were placed on a prenatal vitamin D deficient (PVD) or standard diet for 6 weeks and mated at 10 weeks of age. Females were exposed to either 10%(v/v) ethanol or water between gestational days 0-8 and all were offered water thereafter. We found that blood ethanol concentration in the dams was not affected by maternal diet. Behavioural analyses of the offspring included ultrasonic vocalizations (USV) at postnatal day (P) 7, locomotion and social interaction at P21. The main findings were increased USV calling rate and impaired social interaction in males with prenatal ethanol exposure (PrEE). Gene expression analysis of transcripts involved in dopamine regulation revealed a main effect of ethanol exposure on dopamine- and cyclic adenosine monophosphate- regulated neuronal phosphoprotein (Darpp-32), a main effect of vitamin D diet on Dopamine 2 Receptors (D2R) and a main effect of Sex on Tyrosine Hydroxylase (TH) expression. The combination of PVD-PrEE did not exacerbate the alterations resulting from PVD or PrEE. Despite the limited evidence to support the interaction of PVD and PrEE during the postnatal period, males were more vulnerable than female offspring to the detrimental effects of PrEE. Therefore, based on these studies in mice we suggest that maintenance of optimal vitamin D levels and abstinence from ethanol during pregnancy would reduce risk of later disruption to brain function and behaviour in the offspring.


Assuntos
Comportamento Animal/efeitos dos fármacos , Deficiência de Vitamina D/fisiopatologia , Animais , Animais Recém-Nascidos , Comportamento Animal/fisiologia , Modelos Animais de Doenças , Etanol/efeitos adversos , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Vitamina D/metabolismo
3.
Mem. Inst. Invest. Cienc. Salud (Impr.) ; 11(2): 7-15, dic. 2013. tab
Artigo em Espanhol | LILACS, BDNPAR | ID: lil-714985

RESUMO

El Chaco central paraguayo es unaregión de alto nivel de reinfestación porTriatoma infestans. La población indígena que la habita tiene alta vulnerabilidad por factores culturales y medio ambientales que dificultan acceso y trabajo en la zona. Se propusoconocer factores psicosociales asociadosal proceso de reinfestación para desarrollar tareas de vigilanciacomunitaria. Estudio transversal, con enfoques cualitativo y cuantitativo.Treinta y seis punto siete por ciento (96)de la población de estudio realizómejoras en viviendas; 41,6 % (40)mejoró revoque en paredes. Poblaciónubica al vector en el monte, entre leñas,hojas secas, agujeros de árboles, pozosde topos o tatú; alrededor de animales domésticos, techos de viviendas, gallineros, chiquero de cabras y cerdos.Comprometiendo el traslado pasivo de vinchucas se encontró la recolección deleña 98,5 % (266), del monte, 97,7 %(261) el cambio de lugar de ropas, cajas y comida en las viviendas, 54,7 % (146). Se asoció (p< 0,0005) vivienda mejorada con revoque en paredes yno infestación; viviendas con animales(p< 0,03) e infestación; actitud positivapara eliminar el vector (p<0,04) y no infestación. Comportamientos que comprometen traslado y permanencia de vinchucas fueron acarreo de leña, almacenamiento de comidas yacumulación de ropa y cajas. Paredes revocadas y presencia de animales domésticos se correlacionaron a infestación y actitudes positivas paraeliminación de la vinchuca con viviendas sin reinfestación. Todos ellos sonfactores estratégicos para tareas deprevención y vigilancia con participación comunitaria.


Assuntos
Doença de Chagas , Povos Indígenas , Trypanosoma cruzi
4.
Eur Arch Otorhinolaryngol ; 268(2): 295-301, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20721572

RESUMO

With the increasing use of concomitant chemoradiotherapy (CCRT) in the treatment of advanced head and neck carcinoma, surgery has lost ground as the first therapy and is reserved as a salvage treatment in cases of locoregional failure. The objective of our study was to review our experience in patients who had a local or regional recurrence after treatment with CCRT. Thirty-two patients underwent salvage surgery after CCRT: 24 were treated with a local or locoregional resection and 8 patients with a neck dissection only. In patients who had surgery involving the primary location of the tumor, some kind of reconstruction was required in 83% of cases. One or more postoperative complications occurred in nine patients. The median hospital stay was 18.5 days. There was a significant difference in hospital stay in relation to the appearance of surgical complications. Five-year adjusted survival after salvage surgery was 34.2% (CI 95% 13.2-55.2%). Adjusted survival was related to the status of the resection margins and appearance of neck nodes with extracapsular spread in the neck dissection. In conclusion, salvage surgery after CCRT involves extensive resections, requiring reconstruction techniques with regional or microanastomosed free flaps in most cases, achieving acceptable outcomes.


Assuntos
Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/radioterapia , Neoplasias de Cabeça e Pescoço/radioterapia , Recidiva Local de Neoplasia/cirurgia , Terapia de Salvação , Adulto , Idoso , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/secundário , Feminino , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/mortalidade , Humanos , Masculino , Pessoa de Meia-Idade , Esvaziamento Cervical , Taxa de Sobrevida
5.
Patol. apar. locomot. Fund. Mapfre Med ; 5(1): 31-39, ene.-mar. 2007. ilus, tab
Artigo em Es | IBECS | ID: ibc-056992

RESUMO

Introducción: El esguince agudo de muñeca es el diagnóstico más frecuente en traumatismos agudos de muñeca. Sin embargo, el esguince agudo de muñeca es una de las causas más frecuentes de error diagnóstico inicial en Traumatología. El objetivo de este estudio es conocer la evolución de estas lesiones. Material y métodos: Se desarrollan protocolos de actuación en Urgencias y Consultas Externas para pacientes con traumatismo agudo de muñeca con radiología inicial negativa. Se define la Mala Evolución de Muñeca Aguda Radiológicamente Negativa (MEMARNE). Se analiza la asociación entre MEMARNE y los datos de anamnesis recogidos en Urgencias. Resultados: Entre enero y diciembre de 2005 se recogieron 103 casos de traumatismo agudo de muñeca con radiología inicial negativa. Se produjeron 33 pérdidas de seguimiento. 11,4% de los pacientes presentó radiología positiva en controles posteriores. 28,5% cumplieron criterios MEMARNE. Se desarrolla un score de exploración física para pronosticar la evolución de los traumatismos agudos de muñeca radiológicamente negativos, con una Sensibilidad de 95% y Especificidad de 30%. Conclusiones: Un porcentaje importante de pacientes con traumatismo agudo de muñeca con radiología inicial negativa sufre complicaciones. El MEMARNE score es un instrumento que puede utilizarse para pronosticar la evolución del traumatismo agudo de muñeca


Introduction: Acute wrist sprain is the most common initial diagnosis in acute wrist injuries. Nevertheless, acute wrist sprain is one of the most common erroneous initial diagnosis in Traumatology. The objective of this study is a prospective survey on these injuries. Material and methods: Emergency Department and Consultation protocols were developped. Complicated Evolution of Radiograph-Negative Acute Wrist Injury (CERNAWI) was defined. Results: Between January and December 2005, data from 103 patients was collected. 33 patients were lost to follow up. 11,4% of the patients presented a positive radiograph image during the follow up. 28,5% of the patients’ injuries were considered CERNAWI. A score (CERNAWI score) is developped in order to make prognosis of the evolution of these injuries. Its sensibility was 95% and its specificity 30%. Conclusions: A great number of patients having suffered a radiograph-negative wrist trauma will have a complicated evolution. The CERNAWI score is an item that could be used at Emergency Departments to make prognosis of the acute wrist trauma


Assuntos
Masculino , Feminino , Humanos , Traumatismos do Punho , Estudos Prospectivos , Serviços Médicos de Emergência/estatística & dados numéricos , Traumatismos do Punho/epidemiologia , Osso Escafoide/lesões , Fatores de Risco
6.
Aliment Pharmacol Ther ; 20(1): 29-36, 2004 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-15225168

RESUMO

AIM: To study the pharmacokinetic and metabolism profiles of a single dose of acetaminophen in patients with cirrhosis. METHODS: Oral acetaminophen (1000 mg) was administered to seven healthy subjects and 14 patients with cirrhosis (nine Child-Pugh A or B and five Child-Pugh C grade), being five without and nine with oesophageal varices. Plasma levels of acetaminophen and its metabolites were determined by HPLC. RESULTS: Patients showed a higher mean area under the curve concentration-time (67.4 +/- 22.4 mg h/L vs. 38.8 +/- 4.3 mg h/L; P = 0.01), a lower clearance (166.7 +/- 85.0 mL/min vs. 367.8 +/- 62.5 mL/min; P = 0.01) and higher elimination half-life (3.8 +/- 1.1 h vs. 2.0 +/- 0.4 h; P = 0.01) of acetaminophen than healthy volunteers. The appearance in blood and the urinary excretion of metabolites in patients did not differ from healthy subjects. Absorption profile was faster in patients. Patients with lower mean and systolic arterial pressure had lower AUC of acetaminophen, independently of liver dysfunction stage. CONCLUSIONS: Patients with cirrhosis had a higher AUC and lower clearance of acetaminophen. Acetaminophen attained earlier therapeutic concentrations in patients with oesophageal varices. Mean and systolic arterial pressures were significantly associated with AUC suggesting the importance of the haemodynamic function on the pharmacokinetics of acetaminophen in patients with cirrhosis.


Assuntos
Acetaminofen/farmacocinética , Analgésicos não Narcóticos/farmacocinética , Varizes Esofágicas e Gástricas/metabolismo , Cirrose Hepática/metabolismo , Acetaminofen/administração & dosagem , Administração Oral , Analgésicos não Narcóticos/administração & dosagem , Área Sob a Curva , Cromatografia Líquida de Alta Pressão , Varizes Esofágicas e Gástricas/complicações , Feminino , Meia-Vida , Humanos , Cirrose Hepática/complicações , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
7.
Proc Natl Acad Sci U S A ; 101(9): 2834-9, 2004 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-14978284

RESUMO

An effort to combine theoretical analyses and protein engineering methods has been made to probe the folding mechanism of SH3 by using Energy Landscape Theory and a phi-value analysis. Particular emphasis was given to core residues and the effect of desolvation during the folding event by replacing the core valines with isosteric threonines. These mutations have the advantage of keeping the core structurally invariant while affecting core stability relative to the unfolded state. Although the valines that form the core appear spatially invariant, the folding kinetics of their threonine mutants varies, indicating their different extent of solvation in the transition-state ensemble. Theoretical studies predicted the distribution of folding kinetics of threonine mutants without previous knowledge of the measured rates. This initial success encourages further investigations of the molecular details behind these macroscopic phenomena and of the role of solvation in the folding mechanism.


Assuntos
Conformação Proteica , Dobramento de Proteína , Proteínas/química , Sequência de Aminoácidos , Substituição de Aminoácidos , Modelos Biológicos , Modelos Moleculares , Mutagênese Sítio-Dirigida , Desnaturação Proteica , Proteínas/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Soluções
8.
Gastroenterol Hepatol ; 25(4): 247-50, 2002 Apr.
Artigo em Espanhol | MEDLINE | ID: mdl-11975873

RESUMO

Tamoxifen is an antiestrogenic drug that acts by binding to the estrogen receptor. The drug is used as a co-adjuvant treatment in advanced breast cancer expressing the oestrogen-receptor protein. Clinical trials of tamoxifen have shown its efficacy in reducing mortality and recurrence rates over a five-year treatment. Cases of tamoxifen-associated hepatotoxicity have been described, including cholestasis with or without cytolysis and steatohepatitis. We report the case of a female patient who developed hepatic alterations while undergoing continuous tamoxifen treatment. We also present an overview of similar cases published to date and comment on the advisability of continuing or suppressing this treatment in patients with hepatotoxicity or after a five-year treatment period.


Assuntos
Antineoplásicos Hormonais/efeitos adversos , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Tamoxifeno/efeitos adversos , Feminino , Humanos , Pessoa de Meia-Idade
9.
Farm. hosp ; 25(3): 175-180, mayo 2001. tab
Artigo em Es | IBECS | ID: ibc-8362

RESUMO

El etanol es causa directa de muchos accidentes de circulación.Los efectivos policiales emplean la determinación de alcohol etílico en aire expirado mediante etilómetros de precisión como medida indirecta para conocer la concentración de etanol en sangre.Nuestro estudio pretende comparar la etilometría con la determinación directa de la concentración de etanol en sangre a partir de muestras de suero mediante un método enzimático, así como conocer la concentración de alcohol etílico en una muestra en el momento de su extracción y tras diez días de congelación.Los resultados muestran que no existe buena correlación entre etilometría o medida de etanol en aire expirado y la medida directa en sangre mediante método enzimático. Por otra parte, la congelación se presenta como un método adecuado de transporte y conservación de las muestras que contienen alcohol etílico, hecho ya demostrado en trabajos anteriores. (AU)


Assuntos
Adulto , Feminino , Masculino , Humanos , Acidentes/mortalidade , Alcoolismo/complicações , Etanol/sangue , Manejo de Espécimes/métodos , Espanha , Estudos Retrospectivos
11.
Protein Sci ; 9(12): 2322-8, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11206053

RESUMO

Residue Asn47 at position L1 of a type II' beta-turn of the alpha-spectrin SH3 domain is located in a disallowed region of the Ramachandran plot (phi = 56 +/- 12, psi = -118 +/- 17). Therefore, it is expected that replacement of Asn47 by Gly should result in a considerable stabilization of the protein. Thermodynamic analysis of the N47G and N47A mutants shows that the change in free energy is small (approximately 0.7 kcal/mol; approximately 3 kJ/mol) and comparable to that found when mutating a Gly to Ala in a alpha-helix or beta-sheet. X-ray structural analysis of these mutants shows that the conformation of the beta-turn does not change upon mutation and, therefore, that there is no relaxation of the structure, nor is there any gain or loss of interactions that could explain the small energy change. Our results indicate that the energetic definition of II' region of the Ramachandran plot (phi = 60 +/- 30, psi = -115 +/- 15) should be revised for at least Ala and Asn in structure validation and protein design.


Assuntos
Alanina/química , Asparagina/química , Estrutura Secundária de Proteína , Alanina/farmacologia , Animais , Asparagina/farmacologia , Cristalografia por Raios X , Humanos , Concentração de Íons de Hidrogênio , Cinética , Modelos Moleculares , Mutagênese Sítio-Dirigida , Desnaturação Proteica/efeitos dos fármacos , Dobramento de Proteína , Espectrina/química , Espectrina/genética , Termodinâmica , Ureia/farmacologia , Domínios de Homologia de src/genética
12.
J Biol Chem ; 273(5): 2844-50, 1998 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-9446594

RESUMO

The three-dimensional structure of mouse liver glutathione S-transferase P1-1 carboxymethylated at Cys-47 and its complex with S-(p-nitrobenzyl)glutathione have been determined by x-ray diffraction analysis. The structure of the modified enzyme described here is the first structural report for a Pi class glutathione S-transferase with no glutathione, glutathione S-conjugate, or inhibitor bound. It shows that part of the active site area, which includes helix alphaB and helix 310B, is disordered. However, the environment of Tyr-7, an essential residue for the catalytic reaction, remains unchanged. The position of the sulfur atom of glutathione is occupied in the ligand-free enzyme by a water molecule that is at H-bond distance from Tyr-7. We do not find any structural evidence for a tyrosinate form, and therefore our results suggest that Tyr-7 is not acting as a general base abstracting the proton from the thiol group of glutathione. The binding of the inhibitor S-(p-nitrobenzyl)-glutathione to the carboxymethylated enzyme results in a partial restructuring of the disordered area. The modification of Cys-47 sterically hinders structural organization of this region, and although it does not prevent glutathione binding, it significantly reduces the affinity. A detailed kinetic study of the modified enzyme indicates that the carboxymethylation increases the Km for glutathione by 3 orders of magnitude, although the enzyme can function efficiently under saturating conditions.


Assuntos
Glutationa Transferase/química , Glutationa/análogos & derivados , Isoenzimas/química , Animais , Sítios de Ligação , Cristalografia por Raios X , Cisteína/análogos & derivados , Glutationa/química , Glutationa S-Transferase pi , Glutationa Transferase/antagonistas & inibidores , Iodoacetatos/química , Ácido Iodoacético , Isoenzimas/antagonistas & inibidores , Fígado/enzimologia , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Conformação Proteica
13.
J Pept Sci ; 2(6): 364-70, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-9230464

RESUMO

The conformational preferences of the methylenic sequence in the side chain of the glutamine residue were investigated by ab initio and semi-empirical quantum mechanical calculations and examination of both the Brookhaven Protein Databank and Cambridge Structural Data Base. The results were analysed on the basis of our previous findings about the folding of methylene groups in aliphatic segments. Both energy calculations and the crystallographic structure of small peptides indicate that methylene units of the glutamine residue tend to fold in a gauche conformation. In contrast, such groups usually adopt an all-trans conformation in proteins due basically to the entropic and solvent contributions. These results have been demonstrated by computing the entropic correction to the free energy and evaluating the solvent effects through SCRF calculations.


Assuntos
Glutamina/química , Conformação Proteica , Dobramento de Proteína , Modelos Moleculares , Termodinâmica
14.
Eur J Biochem ; 239(2): 376-83, 1996 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-8706743

RESUMO

Quantum mechanical calculations have been used to investigate the molecular conformation of the Hoechst family of DNA-binding dyestuffs. Compounds in which the phenolic substituent adopts either a meta or para position were studied. Two different environments have been considered, which are the gas phase and aqueous solution; the conformation in aqueous solution has been modeled through a self-consistent reaction field strategy. The results clearly indicate that Hoechst dyes do not adopt a planar conformation and that the degree of planarity is controlled by the external environment. A comparison with experimental data reveals that the conformation of Hoechst dyes in the gas phase is similar to that observed in DNA complexes by X-ray crystallography. In aqueous solution, the conformation deviates from planarity more than in the gas phase, since non-bonded interactions with the solvent offset the loss of conjugative interactions. The role of the drug conformation in the binding mechanism with DNA is discussed.


Assuntos
Benzimidazóis , Bisbenzimidazol , Corantes , DNA , Oligodesoxirribonucleotídeos/química , Sequência de Bases , Benzimidazóis/química , Bisbenzimidazol/química , Corantes/química , Eletroquímica , Análise de Fourier , Modelos Moleculares , Conformação Molecular , Dados de Sequência Molecular , Soluções , Estereoisomerismo , Relação Estrutura-Atividade , Termodinâmica
15.
Nat Med ; 1(1): 84-8, 1995 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-7584960

RESUMO

ATP-induced tumour growth inhibition is accompanied by a selective decrease in the content of the tripeptide glutathione (GSH) within the cancer cells in vivo. Depletion of cellular GSH sensitizes tumours to chemotherapy and radiation, but the usefulness of this depletion depends on whether the levels of GSH can be reduced in the tumour relative to normal tissues. We report here that administration of ATP in combination with diethylmaleate and X-rays leads to complete regression of 95% of Ehrlich ascites tumours in mice. This shows that an aggressive tumour can be eliminated by using a therapy based on modulation of GSH levels in cancer cells.


Assuntos
Trifosfato de Adenosina/uso terapêutico , Carcinoma de Ehrlich/terapia , Glutationa/antagonistas & inibidores , Animais , Antineoplásicos/uso terapêutico , Butionina Sulfoximina , Carcinoma de Ehrlich/tratamento farmacológico , Carcinoma de Ehrlich/radioterapia , Divisão Celular/efeitos dos fármacos , Terapia Combinada , Inibidores Enzimáticos/uso terapêutico , Glutamato-Cisteína Ligase/antagonistas & inibidores , Concentração de Íons de Hidrogênio , Masculino , Maleatos/uso terapêutico , Metionina Sulfoximina/análogos & derivados , Metionina Sulfoximina/uso terapêutico , Camundongos , Radiossensibilizantes/uso terapêutico , Raios X
16.
Eur J Biochem ; 222(3): 721-6, 1994 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-7517864

RESUMO

The molecular structure of the DNA A-tract dodecamer d(CGCAAATTTGCG) complexed with the drug Hoechst 33258 has been determined by X-ray diffraction analysis. The Hoechst molecule binds in the DNA minor groove covering the sequence AATTT of the central A-tract, with the piperazine group close to one of the GC regions. The drug molecule makes two three-centered hydrogen bonds from the nitrogen atoms of the benzimidazole rings to the N3 and O2 atoms of the DNA bases. Although a high propeller twist is observed in the A-tract, only one unsymmetrical three-centered hydrogen bond is present in the DNA major groove. The structure is compared with other minor-groove-binding drug complexes and the influence of these drugs on DNA A-tracts is discussed.


Assuntos
Bisbenzimidazol/metabolismo , DNA/metabolismo , Conformação de Ácido Nucleico , Oligodesoxirribonucleotídeos/metabolismo , Sequência de Bases , Sítios de Ligação , Cristalografia por Raios X , DNA/química , Ligação de Hidrogênio , Processamento de Imagem Assistida por Computador , Modelos Moleculares , Dados de Sequência Molecular , Oligodesoxirribonucleotídeos/química
17.
J Steroid Biochem Mol Biol ; 49(1): 43-9, 1994 May.
Artigo em Inglês | MEDLINE | ID: mdl-8003438

RESUMO

Deflazacort (DFC) is a heterocyclic glucocorticoid with anti-inflammatory activity but with decreased side effects. In this study, we have evaluated the capacity of DFC and other glucocorticoids to reach the central nervous system (CNS) in vivo by measuring changes of [3H]dexamethasone (DEX) binding to glucocorticoid receptors (GR) in vitro. GR occupation was effected by DEX in the cerebral cortex, hippocampus, pituitary, liver and thymus, with DFC showing a similar profile except for the cerebral cortex. In contrast, corticosterone weakly occupied GR in the thymus, pituitary and hippocampus and methyl-prednisolone was active only in peripheral tissues. Furthermore, IC50 for DEX in vitro amounted to 15-17 nM in the hippocampus and liver, whereas IC50 for the active metabolite 21-deacetyl-DFC (21-OH-DFC) was 4 times higher. 21-OH-DFC bound to type II and was absent from type I GR. When tested in equipotent doses based on IC50 analysis, DFC and DEX similarly induced in vivo ornithine decarboxylase activity in hippocampus and liver, although body weight loss after chronic treatment was significantly less for DFC. The results show that DFC distributes on the CNS similarly to DEX, induces ornithine decarboxylase activity but presents less intensive catabolic effects, making it suitable for use as an anti-inflammatory steroid during chronic therapeutic regimes.


Assuntos
Anti-Inflamatórios/metabolismo , Encéfalo/metabolismo , Fígado/metabolismo , Adeno-Hipófise/metabolismo , Pregnenodionas/metabolismo , Receptores de Glucocorticoides/metabolismo , Timo/metabolismo , Animais , Ligação Competitiva , Peso Corporal/efeitos dos fármacos , Córtex Cerebral/metabolismo , Corticosterona/metabolismo , Corticosterona/farmacocinética , Dexametasona/metabolismo , Dexametasona/farmacocinética , Hipocampo/metabolismo , Técnicas In Vitro , Masculino , Metilprednisolona/metabolismo , Metilprednisolona/farmacocinética , Tamanho do Órgão/efeitos dos fármacos , Ornitina Descarboxilase/metabolismo , Prednisona/análogos & derivados , Prednisona/metabolismo , Prednisona/farmacocinética , Pregnenodionas/farmacocinética , Pregnenodionas/farmacologia , Ratos , Ratos Sprague-Dawley
18.
Biochem J ; 298 ( Pt 1): 99-105, 1994 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-8129737

RESUMO

We have investigated the effect of extracellular ATP on tumour-cell proliferation and GSH levels in Ehrlich-ascites-tumour-bearing mice. After daily administration of exogenous ATP (1 mmol/kg) during 7 days, we found a 56% inhibition of tumour growth, precisely when controls show the highest rates of cell proliferation and the highest levels of GSH. This effect is accompanied by a decrease in GSH content in the tumour, but not in normal tissues. The decrease in GSH concentration within the cancer cells is associated with a decrease in gamma-glutamylcysteine synthetase activity and in protein synthesis. Growth inhibition is mediated by generation of extracellular adenosine, which subsequently increases intracellular levels of ATP and decreases intracellular levels of UTP in the cancer cells. Our results suggest that inhibition of tumour growth by ATP is due to an adenosine-dependent pyrimidine starvation effect.


Assuntos
Trifosfato de Adenosina/farmacologia , Antineoplásicos/farmacologia , Carcinoma de Ehrlich/metabolismo , Glutationa/metabolismo , Adenosina/metabolismo , Adenosina/farmacologia , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/sangue , Animais , Carcinoma de Ehrlich/patologia , Divisão Celular/efeitos dos fármacos , Eritrócitos/metabolismo , Glutationa/biossíntese , Masculino , Camundongos , Células Tumorais Cultivadas , Uridina Trifosfato/metabolismo
19.
J Biomol Struct Dyn ; 11(2): 429-41, 1993 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8286066

RESUMO

This study presents the influence of the dielectric constant on the final structure of the major antigenic loop of the FMDV serotype C. Minimizations have been performed on the nine-residue peptide Ac-TASARGDLA-NHMe, using two expressions for the dielectric constant: a distance-independent (epsilon = kappa), and a distance-dependent (epsilon = kappa *r) forms, and for kappa values from 1 to 10. In addition, kappa = 40 and 80 has also been considered for the constant expression of the dielectrics. The calculations suggest, for both expressions of the dielectrics, that for the sequence under study a value of kappa in the range of 2-6 performs an adequate treatment of the electrostatic interactions. Finally, molecular dynamic simulations at 298 K calculated with an effective dielectric constants of epsilon = 1*r and epsilon = 4*r are compared. The results indicated that a dielectric of epsilon = 4*r provides a peptide fluctuations which are in agreement with recent X-ray diffraction studies.


Assuntos
Antígenos Virais/química , Aphthovirus/imunologia , Capsídeo/química , Oligopeptídeos/química , Algoritmos , Sequência de Aminoácidos , Proteínas do Capsídeo , Simulação por Computador , Eletroquímica , Ligação de Hidrogênio , Dados de Sequência Molecular , Conformação Proteica , Difração de Raios X
20.
Biochem J ; 292 ( Pt 2): 477-83, 1993 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-8503882

RESUMO

We have investigated in Ehrlich-ascites-tumour-bearing mice the effect of buthionine sulphoximine (BSO), a selective inhibitor of GSH synthesis, on the rate of GSH depletion of tumour versus normal tissues and its relation to tumour cell proliferation. In normal tissues, GSH and GSSG remain unchanged or close to normal values during tumour growth, even at the last stage of growth when the animal is close to death. After administration of a single dose of BSO (4 mmol/kg), the rates of GSH depletion and recovery in the tumour and in several normal tissues are very different. BSO depletes GSH in cancer cells to a level of 0.3-0.4 mumol/g. The fall in GSH levels is faster when tumour cells do not proliferate actively. Four treatments of 4 mmol of BSO/kg at 48 h intervals induce a significant decrease (about 44%) in tumour growth. Our data show that the rate of BSO-induced GSH depletion in cancer cells depends on the stage of tumour growth, and that BSO administration also inhibits cancer-cell proliferation. A mechanism involving changes in protein kinase C activity and intracellular pH is proposed to explain the inhibition of cancer growth elicited by BSO.


Assuntos
Antimetabólitos Antineoplásicos/farmacologia , Carcinoma de Ehrlich/metabolismo , Glutationa/metabolismo , Metionina Sulfoximina/análogos & derivados , Animais , Butionina Sulfoximina , Carcinoma de Ehrlich/tratamento farmacológico , Divisão Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Masculino , Metionina Sulfoximina/farmacologia , Camundongos
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