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1.
Clin Oncol (R Coll Radiol) ; 36(9): e301-e311, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38849235

RESUMO

AIMS: WHO Grade 3 (G3) meningiomas are rare tumours with limited data to guide management. This retrospective study documents UK management approaches across 14 centres over 11 years. MATERIALS AND METHODS: Patients with WHO G3 meningioma between 01/01/2008 and 31/12/2018 were identified. Data were collected on demographics, management strategy, adjuvant radiotherapy, approach in recurrence setting and survival. RESULTS: 84 patients were identified. 21.4% transformed from lower-grade disease. 96.4% underwent primary surgical resection, with 20.8% having evidence of residual disease on their post-op MRI. 59.3% of patients underwent adjuvant radiotherapy (RT) following surgical resection. Overall median PFS and OS were 12.6 months and 28.2 months, respectively. Median OS in the group who underwent complete surgical resection was 34.9 months, compared to 27.5 months for those who had incomplete resection (HR 0.58, 95% CI 0.27-1.23, p = 0.15). Median OS was 33.1 months for those who underwent adjuvant RT and 14.0 months for those who did not (HR 0.48, 95% CI 0.27-0.84, p = 0.004). Median adjuvant RT dose delivered was 60Gy (range 12Gy-60Gy), 45.8% of adjuvant RT was delivered using IMRT. At disease relapse, 31% underwent salvage surgery and 29.3% underwent salvage RT. Of those treated with salvage RT, 64.7% were re-treats and all were treated with hypofractionated RT. CONCLUSION: Surgery continues to be the preferred primary management strategy. Post-operative MRI within 48 hours is indicated to assess presence of residual disease and guide further surgical options. Adjuvant radiotherapy plays an important part of the management paradigm in these patients with the data supporting an attached survival advantage. Further surgery and re-irradiation is an option in the disease recurrence setting with radiosurgery frequently utilised in this context.


Assuntos
Neoplasias Meníngeas , Meningioma , Humanos , Estudos Retrospectivos , Masculino , Feminino , Meningioma/radioterapia , Meningioma/patologia , Meningioma/mortalidade , Meningioma/terapia , Meningioma/cirurgia , Pessoa de Meia-Idade , Reino Unido , Idoso , Neoplasias Meníngeas/radioterapia , Neoplasias Meníngeas/patologia , Neoplasias Meníngeas/terapia , Neoplasias Meníngeas/cirurgia , Radioterapia Adjuvante , Adulto , Gradação de Tumores , Idoso de 80 Anos ou mais , Recidiva Local de Neoplasia/radioterapia
2.
BJS Open ; 5(2)2021 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-33688944

RESUMO

BACKGROUND: There are marked geographical variations in the proportion of patients undergoing resection for gastric cancer. This study investigated the impact of resection rate on survival. METHODS: All patients with potentially curable gastric cancer between 2006 and 2017 were identified from the Swedish National Register of Oesophageal and Gastric Cancer. The annual resection rate was calculated for each county per year. Resection rates in all counties for all years were grouped into tertiles and classified as low, intermediate or high. Survival was analysed using the Cox proportional hazards model. RESULTS: A total of 3465 patients were diagnosed with potentially curable gastric cancer, and 1934 (55.8 per cent) were resected. Resection rates in the low (1261 patients), intermediate (1141) and high (1063) tertiles were 0-50.0, 50.1-62.5 and 62.6-100 per cent respectively. The multivariable Cox analysis revealed better survival for patients diagnosed in counties during years with an intermediate versus low resection rate (hazard ratio (HR) 0.81, 95 per cent c.i. 0.74 to 0.90; P < 0.001) and high versus low resection rate (HR 0.80, 0.73 to 0.88; P < 0.001). CONCLUSION: This national register study showed large regional variation in resection rates for gastric cancer. A higher resection rate appeared to be beneficial with regard to overall survival for the entire population.


Assuntos
Adenocarcinoma/mortalidade , Adenocarcinoma/cirurgia , Neoplasias Gástricas/mortalidade , Neoplasias Gástricas/cirurgia , Adenocarcinoma/patologia , Idade de Início , Feminino , Humanos , Masculino , Gradação de Tumores , Estadiamento de Neoplasias , Modelos de Riscos Proporcionais , Sistema de Registros , Fatores de Risco , Sensibilidade e Especificidade , Neoplasias Gástricas/patologia , Taxa de Sobrevida , Suécia/epidemiologia
3.
Br J Surg ; 107(11): 1500-1509, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32484241

RESUMO

BACKGROUND: Only around one-quarter of patients with cancer of the oesophagus and the gastro-oesophageal junction (GOJ) undergo surgical resection. This population-based study investigated the rates of treatment with curative intent and resection, and their association with survival. METHODS: Patients diagnosed with oesophageal and GOJ cancer between 2006 and 2015 in Sweden were identified from the National Register for Oesophageal and Gastric Cancer (NREV). The NREV was cross-linked with several national registries to obtain information on additional exposures. The annual proportion of patients undergoing treatment with curative intent and surgical resection in each county was calculated, and the counties divided into groups with low, intermediate and high rates. Treatment with curative intent was defined as definitive chemoradiation therapy or surgery, with or without neoadjuvant oncological treatment. Overall survival was analysed using a multilevel model based on county of residence at the time of diagnosis. RESULTS: Some 5959 patients were included, of whom 1503 (25·2 per cent) underwent surgery. Median overall survival after diagnosis was 7·7, 8·8 and 11·1 months respectively in counties with low, intermediate and high rates of treatment with curative intent. Corresponding survival times for the surgical resection groups were 7·4, 9·3 and 11·0 months. In the multivariable analysis, a higher rate of treatment with curative intent (time ratio 1·17, 95 per cent c.i. 1·05 to 1·30; P < 0·001) and a higher resection rate (time ratio 1·24, 1·12 to 1·37; P < 0·001) were associated with improved survival after adjustment for relevant confounders. CONCLUSION: Patients diagnosed in counties with higher rates of treatment with curative intent and higher rates of surgery had better survival.


ANTECEDENTES: En los pacientes con cáncer en el esófago y de la unión gastroesofágica (gastroesophageal junction, GOJ), solamente en una cuarta parte se practica una resección quirúrgica. Este estudio de base poblacional analizó las tasas de tratamiento con intención curativa y de resección y su asociación con la supervivencia. MÉTODOS: A partir del Registro Nacional Sueco de Cáncer de Esófago y Estómago (National Register for Oesophageal and Gastric Cancer, NREV), se identificaron los pacientes diagnosticados de cáncer de esófago y de la GOJ entre 2006-2015. El NREV se cruzó con otros registros nacionales para obtener información adicional. Se calculó la proporción anual de pacientes tratados con intención curativa o mediante resección quirúrgica en cada una de las áreas territoriales de los condados y se categorizaron en baja, intermedia y alta. El tratamiento con intención curativa se definió como la quimiorradioterapia definitiva (definitive chemoradiation therapy, dCRT) o la cirugía, con o sin tratamiento oncológico neoadyuvante. Se analizó la supervivencia global con un modelo multinivel basado en el condado de residencia en el momento del diagnóstico. RESULTADOS: Se incluyeron 5.959 pacientes, de los que 1.503 (25,2%) fueron tratados quirúrgicamente. La mediana de supervivencia global después del tratamiento con intención curativa fue de 7,7, 8,8 y 11,1 meses para los condados de volumen bajo, intermedio y alto. Para el grupo de cirugía fue de 7,4, 9,3 y 11,0 meses, respectivamente. En el análisis multivariable, una mayor tasa de tratamiento con intención curativa y una mayor tasa de resección se asociaron con una mejor supervivencia (tiempo ganado 1,17; i.c. del 95% 1,05-1,30, P < 0,001 y tiempo ganado 1,24; i.c. del 95% 1,12-1,37, P < 0,001) después del ajuste para los factores principales de confusión. CONCLUSIÓN: Los pacientes diagnosticados en condados con tasas altas de tratamiento con intención curativa y de cirugía tuvieron una mejor supervivencia.


Assuntos
Adenocarcinoma/terapia , Carcinoma de Células Escamosas/terapia , Neoplasias Esofágicas/terapia , Junção Esofagogástrica , Disparidades em Assistência à Saúde/estatística & dados numéricos , Padrões de Prática Médica/estatística & dados numéricos , Neoplasias Gástricas/terapia , Adenocarcinoma/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/mortalidade , Quimiorradioterapia/estatística & dados numéricos , Neoplasias Esofágicas/mortalidade , Esofagectomia/estatística & dados numéricos , Junção Esofagogástrica/cirurgia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante/estatística & dados numéricos , Sistema de Registros , Estudos Retrospectivos , Neoplasias Gástricas/mortalidade , Análise de Sobrevida , Suécia/epidemiologia , Resultado do Tratamento
4.
Vaccine ; 21(17-18): 1995-2002, 2003 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-12706689

RESUMO

A series of phase I clinical studies were conducted to evaluate the safety of plasmid DNA and modified vaccinia virus Ankara malaria vaccines. The vaccines each encoded a polyepitope string fused to whole Plasmodium falciparum TRAP antigen. Forty-three healthy adult volunteers received the vaccines alone or in DNA/MVA prime-boost combinations. The DNA vaccine was administered either intramuscularly by needle or intradermally by a needleless delivery device. The MVA vaccine was administered intradermally by needle. The vaccines were well-tolerated by all three routes and in various DNA/MVA immunisation regimes. There were no severe or serious adverse events.


Assuntos
Fígado/parasitologia , Vacinas Antimaláricas/normas , Malária Falciparum/imunologia , Vacinas de DNA/normas , Vaccinia virus/imunologia , Vacinas Virais/imunologia , Adulto , Sequência de Aminoácidos , Antígenos de Protozoários/genética , Antígenos de Protozoários/imunologia , Proteínas Aviárias/genética , Proteínas Aviárias/imunologia , Epitopos/química , Epitopos/imunologia , Proteínas do Olho/genética , Proteínas do Olho/imunologia , Feminino , Humanos , Injeções Intramusculares , Vacinas Antimaláricas/administração & dosagem , Vacinas Antimaláricas/efeitos adversos , Masculino , Pessoa de Meia-Idade , Plasmídeos/imunologia , Prurido/induzido quimicamente , Segurança , Vacinas de DNA/administração & dosagem , Vacinas Virais/efeitos adversos , Vacinas Virais/normas
5.
Vaccine ; 19(32): 4595-602, 2001 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-11535306

RESUMO

Two chimpanzees were vaccinated intramuscularly against malaria using plasmid DNA expressing the pre-erythrocytic antigens thrombospondin related adhesion protein (PfTRAP) and liver stage specific antigen-1 (PfLSA-1) of Plasmodium falciparum together with GM-CSF protein. A recombinant modified vaccinia virus Ankara (MVA) expressing PfTRAP was injected intramuscularly 6 weeks later to boost the immune response. This sequence of antigen delivery induced a specific and long-lasting T cell and antibody response to PfTRAP as detected by ELISPOT assay and ELISA. Antibody responses were detected after four DNA injections, and were boosted by injection of recombinant MVA expressing PfTRAP. Interferon-gamma secreting antigen-specific T cells were detected in both animals, but only after boosting with recombinant MVA. By screening a panel of PfTRAP-derived peptides, an epitope was identified that was recognized by cytotoxic T lymphocytes in one of the chimpanzees studied. T cells specific for this epitope were present in PBMCs and liver-infiltrating lymphocytes at a frequency of between 1 in 200 and 1 in 500. The high immunogenicity of this prime-boost regimen in chimpanzees supports further assessment of this delivery strategy for the induction of protection against P. falciparum malaria in humans.


Assuntos
Antígenos de Protozoários/imunologia , Esquemas de Imunização , Imunização Secundária , Vacinas Antimaláricas/administração & dosagem , Plasmodium falciparum/imunologia , Proteínas de Protozoários/imunologia , Linfócitos T Citotóxicos/imunologia , Vacinas de DNA/administração & dosagem , Vaccinia virus/genética , Animais , Anticorpos Antiprotozoários/biossíntese , Antígenos de Protozoários/genética , Células COS , Embrião de Galinha , Chlorocebus aethiops , DNA de Protozoário/genética , Ensaio de Imunoadsorção Enzimática , Epitopos/imunologia , Fibroblastos/virologia , Vetores Genéticos/genética , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Humanos , Imunidade Celular , Leucócitos Mononucleares/imunologia , Vacinas Antimaláricas/imunologia , Masculino , Pan troglodytes , Proteínas de Protozoários/genética , Proteínas Recombinantes/farmacologia , Transfecção , Vacinas de DNA/imunologia
6.
Dev Biol (Basel) ; 104: 171-9, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11713817

RESUMO

A generic approach to inducing high level CD8+ T cell responses would be of value for prophylactic and therapeutic immunisation against several infectious diseases. However, it has been very difficult to achieve such immune responses using available vaccination strategies. Malaria is one of several diseases against which a new generation of better CD8+ T cell-inducing vaccines might be useful and is unusual in that it allows assessment of vaccine efficacy in small numbers of volunteers in carefully controlled challenge studies. Here we review the identification of a heterologous prime-boost regime using DNA priming and recombinant modified vaccinia Ankara (MVA) boosting that induces high level T cell responses in both mice and non-human primates. Clinical trials to determine whether this prime-boost approach is immunogenic in humans are in progress.


Assuntos
Vacinas Antimaláricas/administração & dosagem , Vacinas de DNA/administração & dosagem , Adjuvantes Imunológicos/administração & dosagem , Animais , Linfócitos T CD8-Positivos/imunologia , Ensaios Clínicos Fase I como Assunto , Vetores Genéticos , Humanos , Imunização Secundária , Imunoensaio , Fígado/parasitologia , Malária/imunologia , Malária/parasitologia , Malária/prevenção & controle , Primatas , Vaccinia virus/genética , Vaccinia virus/imunologia
7.
Vaccine ; 18(7-8): 623-32, 1999 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-10547421

RESUMO

In influenza and malaria, CD8+ T cells play an important role in protective immunity in mice. An immunization strategy consisting of DNA priming followed by boosting with recombinant modified vaccinia virus Ankara (MVA) induces complete protection, associated with high levels of CD8+ T cells, against Plasmodium berghei sporozoite challenge in mice. Intradermal delivery of DNA with a gene gun requires smaller amounts of DNA than intramuscular injection, in order to induce similar levels of immune responses. The present study compares both routes for the induction of specific CD8+ T cell responses and protection using different prime-boost immunization regimes in the influenza and the malaria models. In the DNA/MVA regime, equally high CD8+ T cell responses and levels of protection are achieved using ten times less DNA when delivered with a gene gun compared to intramuscular injection.


Assuntos
Biolística , Linfócitos T CD8-Positivos/imunologia , Vacinas contra Influenza/administração & dosagem , Vacinas Antimaláricas/administração & dosagem , Malária/prevenção & controle , Infecções por Orthomyxoviridae/prevenção & controle , Vacinas de DNA/administração & dosagem , Vaccinia virus/genética , Animais , DNA de Protozoário/administração & dosagem , DNA de Protozoário/genética , DNA Viral/administração & dosagem , DNA Viral/genética , Feminino , Imunização Secundária , Vacinas contra Influenza/genética , Vacinas contra Influenza/imunologia , Malária/imunologia , Vacinas Antimaláricas/genética , Vacinas Antimaláricas/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Infecções por Orthomyxoviridae/imunologia , Plasmodium berghei/imunologia , Vacinas Atenuadas/administração & dosagem , Vacinas Atenuadas/genética , Vacinas Atenuadas/imunologia , Vacinas de DNA/genética , Vacinas de DNA/imunologia , Vaccinia virus/imunologia
8.
Immunol Rev ; 170: 29-38, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10566139

RESUMO

One of the current challenges in vaccine design is the development of antigen delivery systems or vaccination strategies that induce high protective levels of CD8+ T cells. These cells are crucial for protection against certain tumours and intracellular pathogens such as the liver-stage parasite of malaria. A liver-stage malaria vaccine should therefore include CD8+ T-cell-inducing components. This review provides an overview of prime-boost immunisation strategies that result in protective CD8+ T-cell responses against malaria with an emphasis on work from our laboratory. Possible mechanisms explaining why heterologous prime-boost strategies, in particular boosting with replication-impaired recombinant poxviruses, are so effective are discussed.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Imunização Secundária/métodos , Adjuvantes Imunológicos/administração & dosagem , Animais , Epitopos/administração & dosagem , Vetores Genéticos , Humanos , Malária/imunologia , Malária/prevenção & controle , Vacinas Antimaláricas/administração & dosagem , Camundongos , Primatas , Vacinas de DNA/administração & dosagem
9.
Biol Chem ; 380(3): 299-303, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10223332

RESUMO

Three types of vaccine, all expressing the same antigen from Plasmodium berghei, or a CD8+ T cell epitope from that antigen, were compared for their ability to induce CD8+ T cell responses in mice. Higher levels of lysis and numbers of IFN-gamma secreting T cells were primed with Ty virus-like particles and Modified Vaccinia Virus Ankara (MVA) than with DNA vaccines, but none of the vaccines were able to protect immunised mice from infectious challenge even after repeated doses. However, when the immune response was primed with one type of vaccine (Ty-VLPs or DNA) and boosted with another (MVA) complete protection against infection was achieved. Protection correlated with very high levels of IFN-gamma secreting T cells and lysis. This method of vaccination uses delivery systems and routes that can be used in humans and could provide a generally applicable regime for the induction of high levels of CD8+ T cells.


Assuntos
Antígenos de Protozoários/imunologia , Vacinas Antimaláricas/imunologia , Malária/prevenção & controle , Plasmodium berghei/imunologia , Proteínas de Protozoários/imunologia , Vacinas de DNA/imunologia , Vaccinia virus/imunologia , Animais , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Recombinantes de Fusão/imunologia , Retroelementos , Vírion/imunologia
10.
Nat Med ; 5(5): 565-71, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10229235

RESUMO

Variation in epitopes of infectious pathogens inhibits various effector functions of T lymphocytes through antagonism of the T-cell receptor. However, a more powerful strategy for immune evasion would be to prevent the induction of T-cell responses. We report here mutual 'interference' with the priming of human T-cell responses by a pair of naturally occurring variants of a malaria cytotoxic T-cell epitope. Interference with priming also occurs in vivo for a murine malaria T-cell epitope. Reshaping of the T-cell repertoire by such immune interference during naive T-cell induction may provide a general mechanism for observed patterns of immunodominance and persistence by many polymorphic pathogens.


Assuntos
Variação Antigênica , Antígenos de Protozoários/imunologia , Ativação Linfocitária , Malária Falciparum/imunologia , Linfócitos T/imunologia , Apresentação de Antígeno , Epitopos , Humanos , Ligantes , Fragmentos de Peptídeos/imunologia , Proteínas de Protozoários/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Linfócitos T Citotóxicos
11.
Eur J Immunol ; 28(12): 4345-55, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9862371

RESUMO

The desirability of inducing cytotoxic T cell responses to defined epitopes in humans has led to the development of a variety of recombinant delivery systems. Recombinant protein particles derived from a yeast retrotransposon (Ty) and the modified Ankara vaccinia (MVA) virus can deliver large epitope strings or even whole proteins. Both have previously been administered safely in humans. Immunization with recombinant Ty and MVA containing a single Plasmodium berghei class I-binding epitope provided 95% sterile protection against malaria in mice. The sequence of immunization, Ty followed by MVA, was critical to elicit high levels of IFN-gamma-producing cells and protection. The reciprocal sequence (MVA/TY) or homologous boosting was not protective. Both constructs (Ty and MVA) contain the H-2Kd-restricted pb9 CTL epitope from the circumsporozoite protein of P. berghei among a string of 8-15 human P. falciparum-derived CTL epitopes restricted through 7 common HLA alleles as well as widely recognized CD4 T cell epitopes. Thus, the novel recombinant Ty/MVA prime/boost combination with these constructs provides a safe alternative for evaluation for human vaccination against P. falciparum malaria.


Assuntos
Antígenos de Protozoários/imunologia , Sistemas de Liberação de Medicamentos , Antígenos de Histocompatibilidade Classe I/imunologia , Vacinas Antimaláricas , Malária/imunologia , Plasmodium berghei/imunologia , Linfócitos T/imunologia , Animais , Citotoxicidade Imunológica , Humanos , Malária/prevenção & controle , Camundongos , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia
12.
Nat Med ; 4(4): 397-402, 1998 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9546783

RESUMO

Immunization with irradiated sporozoites can protect against malaria infection and intensive efforts are aimed at reproducing this effect with subunit vaccines. A particular sequence of subunit immunization with pre-erythrocytic antigens of Plasmodium berghei, consisting of single dose priming with plasmid DNA followed by a single boost with a recombinant modified vaccinia virus Ankara (MVA) expressing the same antigen, induced unprecedented complete protection against P. berghei sporozoite challenge in two strains of mice. Protection was associated with very high levels of splenic peptide-specific interferon-gamma-secreting CD8+ T cells and was abrogated when the order of immunization was reversed. DNA priming followed by MVA boosting may provide a general immunization regime for induction of high levels of CD8+ T cells.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Imunização Secundária , Vacinas Antimaláricas , Malária/imunologia , Plasmodium berghei/imunologia , Vacinas de DNA , Vaccinia virus/imunologia , Animais , Anopheles/parasitologia , Células Cultivadas , Embrião de Galinha , Citotoxicidade Imunológica , Feminino , Humanos , Interferon gama/biossíntese , Interleucina-2/farmacologia , Ativação Linfocitária/efeitos dos fármacos , Malária/prevenção & controle , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Plasmídeos , Plasmodium berghei/crescimento & desenvolvimento , Plasmodium berghei/isolamento & purificação , Especificidade da Espécie , Baço/imunologia
13.
Vaccine ; 16(5): 439-45, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9491498

RESUMO

Human immunodeficiency virus (HIV) vaccine candidates were previously constructed as a string of cytotoxic T lymphocyte (CTL) epitopes delivered and expressed using DNA and modified virus Ankara (MVA; an attenuated vaccinia virus) vectors. These vaccines were shown to induce interferon (IFN)-gamma-producing and cytolytic CD8+ T cells after a single vaccine administration. In the course of this work, immunization protocols were sought which would improve the levels of induced HIV-specific T cells. It was found that previous immunological exposure to MVA reduced the efficiency of subsequent priming and boosting using the same vaccine vehicle. However, a combined regime whereby the animals were first primed with the DNA vaccine and then boosted with MVA was the most potent protocol for the induction of both interferon-gamma-producing and cytolytic T cells against two CTL epitopes simultaneously. The general applicability of this novel vaccination method for induction of major histocompatibility complex class I-restricted T cells is discussed.


Assuntos
DNA Viral , Antígenos de Histocompatibilidade Classe I/imunologia , Peptídeos/imunologia , Linfócitos T Citotóxicos/imunologia , Vaccinia virus/imunologia , Vacinas Virais , Animais , Linfócitos T CD8-Positivos/imunologia , Células Cultivadas , Epitopos , Feminino , Imunização Secundária , Indutores de Interferon , Interferon gama/biossíntese , Camundongos , Camundongos Endogâmicos BALB C , Vacinas Atenuadas
14.
Anticancer Res ; 17(3C): 2083-8, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9216668

RESUMO

Tumor cell resistance to many unrelated anticancer drugs is a major obstacle during cancer chemotherapy. One mechanism of drug resistance is thought to be due to the efflux of anticancer drugs caused by P-glycoprotein. In recent years, magnetic fields have been found to enhance the potency of anticancer drugs, with favorable modulation of cancer therapy. In this study, KB-ChR-8-5-11, a multidrug resistant (MDR) human carcinoma subline, was used as a model to evaluate the ability of pulsed magnetic fields (PMF) to modulate the potency of daunorubicin (DNR) in vivo and to determine the appropriate order of exposure to drugs and PMF using an in vitro cytotoxicity assay. Solenoid coils with a ramped pulse current source were used at 250 pulses per second for both in vivo and in vitro experiments. For the in vivo study, KB-ChR-8-5-11 cells were inoculated into thymic Balbc-nu/nu female mice. Treatment was begun when the average tumor volume reached 250-450 mm3. Treatment consisted of whole body exposure to PMF for one hour, followed immediately by intravenous (i.v.) injection of 8 mg/kg DNR designated as day 0, and repeated on days 7 and 14. Among the various groups, significant differences in the tumor volume were found between PMF + saline and PMF + DNR groups (p = 0.0107) at 39 days and 42 days (p = 0.0101). No mice died in the PMF alone group, and no toxicity attributable to PMF was found during the experimental period. For the in vitro studies, the sulforhodamine blue (SRB) cytotoxicity assay was used to determine the effect of the sequence which cells are exposed to PMF and/or DNR. Cells were exposed to PMF either before (pre-PMF) or after (post-PMF) drug was added. Results showed that the IC50 was significantly different between controls and pre-PMF + DNR groups (P = 0.0096, P = 0.0088). The IC50 of the post-PMF + DNR group was not found to be significantly different from control groups. Thus, the data in this report demonstrates that PMF enhanced the potency of DNR against KB-ChR-8-5-11 xenograft in vivo, while the efficacy of DNR was potentiated in vitro by PMF exposure only when PMF exposure occurred in the presence of drug. The data in vitro suggest that the mechanism by which PMFs modulate DNR's potency may be by inhibition of the efflux pump, P-glycoprotein. Further work to determine conditions for maximum modulation of drug potency by PMFs is warranted.


Assuntos
Daunorrubicina/toxicidade , Resistência a Múltiplos Medicamentos/efeitos da radiação , Magnetismo , Animais , Células Clonais , Terapia Combinada , Daunorrubicina/uso terapêutico , Feminino , Humanos , Células KB , Magnetismo/uso terapêutico , Camundongos , Camundongos Nus , Neoplasias Nasofaríngeas/tratamento farmacológico , Neoplasias Nasofaríngeas/radioterapia , Transplante Heterólogo
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