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1.
Praxis (Bern 1994) ; 93(24): 1051-4, 2004 Jun 09.
Artículo en Francés | MEDLINE | ID: mdl-15318531

RESUMEN

A 70 year old heart and renal transplanted man was hospitalized twice for acute abdominal pain with jaundice, inflammatory syndrome and cholestasis following colchicine therapy. All signs and symptoms abated after colchicine's withdrawal. Because the investigations remained negative and the temporal relationship positive, an adverse drug reaction to colchicine was considered possible.


Asunto(s)
Abdomen Agudo/etiología , Enfermedad Hepática Inducida por Sustancias y Drogas/diagnóstico , Colestasis Intrahepática/inducido químicamente , Colchicina/efectos adversos , Gota/tratamiento farmacológico , Anciano , Colestasis Intrahepática/diagnóstico , Colchicina/uso terapéutico , Diagnóstico Diferencial , Trasplante de Corazón , Humanos , Trasplante de Riñón , Masculino , Complicaciones Posoperatorias/diagnóstico , Recurrencia
2.
Praxis (Bern 1994) ; 93(19): 797-801, 2004 May 05.
Artículo en Francés | MEDLINE | ID: mdl-15185486

RESUMEN

Each year, drugs must be withdrawn from the market following the identification of serious adverse reactions. We report here on an enquiry addressed to persons involved in the recent withdrawal of nefazodone, and a survey of physicians and pharmacists. Our results show the complexities of such withdrawal decisions and the difficulty in communicating them through the network of health professionals down to the patients.


Asunto(s)
Sistemas de Registro de Reacción Adversa a Medicamentos/legislación & jurisprudencia , Antidepresivos de Segunda Generación/toxicidad , Industria Farmacéutica/legislación & jurisprudencia , Servicios de Información sobre Medicamentos/legislación & jurisprudencia , Triazoles/toxicidad , Actitud del Personal de Salud , Enfermedad Hepática Inducida por Sustancias y Drogas/etiología , Comunicación , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Humanos , Relaciones Interprofesionales , Piperazinas , Suiza
3.
J Pept Res ; 57(2): 85-96, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11168892

RESUMEN

A complete 331,776-member library of tetrapeptides made of 24 amino acid building blocks was synthesized robotically on solid phase and subjected to a deconvolution based on the inhibitory potency of the sublibraries in a HPLC assay of the S-farnesyltransferase activity in vitro. One of the non-natural peptide and noncysteine-containing leads Nip-Trp-Phe-His (Nip=p-nitrophenyl-L-alanine) was optimized chemically to give a proteolytically stable pseudopeptide with a 200-fold potency compared with the original lead. The final compound was converted to the C-terminal ethyl ester: p-F-C6H4-CO(CH2)2-CO-Bta-D-Phepsi[CH2NH]His-OEt (Bta = benzothienyl-L-alanine) and shown to behave as a prodrug which was hydrolyzed back to the C-terminal acid following cell penetration. The method confirmed that several structurally original leads can be discovered in large libraries when deconvolution relies upon a highly specific assay and that these leads can be optimized by chemical modification to impart the final compound the desired pharmacological and pharmacokinetic properties.


Asunto(s)
Transferasas Alquil y Aril/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Biblioteca de Péptidos , Péptidos/farmacología , Transferasas Alquil y Aril/metabolismo , Línea Celular , Cromatografía Líquida de Alta Presión , Inhibidores Enzimáticos/química , Farnesiltransferasa , Ligandos , Péptidos/metabolismo
4.
Eur J Surg Oncol ; 26(7): 669-78, 2000 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11078614

RESUMEN

AIMS: Patients with non-resectable soft tissue sarcomas of the extremities do not live longer if they are treated by amputation or disarticulation. In order to avoid major amputations, we tested isolated limb perfusion (ILP) with tumour necrosis factor alpha (TNF)+melphalan+/-interferon-gamma (IFN) as a pre-operative, neoadjuvant limb salvage treatment. METHODS: Twenty-two patients were included (six men and 16 women; three upper limb and 19 lower limb tumours). The AJCC stage was IIA in four patients, III in seven and IV in 11. Thirteen cases were recurrent or progressive after previous therapy; five tumours had a diameter >/=20 cm, and four were multiple or regionally metastatic. There were six malignant fibrous histiocytomas, five liposarcomas, four malignant peripheral nerve sheath tumours, three rhabdomyosarcomas, two leiomyosarcomas, one recurrent extraskeletal osteosarcoma and one angiosarcoma. RESULTS: Twenty-four ILPs were performed in the 22 patients, and 18 (82%) experienced an objective response: this was complete in four (18%) and partial in 14 (64%). Three patients had a minimal or no response and the tumour progressed in one case. All patients had fever for 24 hours but only one developed a reversible grade 3 distributive shock syndrome with no sequelae. There was no grade 4 toxicity. Seventeen patients (77%) underwent limb-sparing resection of the tumour remnants after a median time of 3.4 months: 10 resections were intracompartmental and seven extracompartmental. Surgery included flaps or skin grafts in five patients, arterial replacement in two and knee arthrodesis in one. Adjuvant chemotherapy was given to eight patients and radiotherapy to six. In one patient amputation was necessary after a second ILP. Secondary amputations were performed for recurrence in two patients, resulting in an overall limb salvage rate of 19/22 (86%). After a median follow-up of 18.7 months, 10 recurrences were recorded: seven were both local and systemic and three were only local. The median disease free and overall survival times have been >12.5 and 18.7 months respectively: this is similar to the outcome after primary amputations for similar cases. CONCLUSION: ILP with TNF and chemotherapy is an efficient limb sparing neoadjuvant therapy for a priori non-resectable limb soft tissue sarcomas.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Pierna/cirugía , Sarcoma/tratamiento farmacológico , Sarcoma/cirugía , Neoplasias de los Tejidos Blandos/tratamiento farmacológico , Neoplasias de los Tejidos Blandos/cirugía , Adulto , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Quimioterapia Adyuvante , Quimioterapia del Cáncer por Perfusión Regional , Supervivencia sin Enfermedad , Doxorrubicina/administración & dosificación , Femenino , Humanos , Ifosfamida/administración & dosificación , Interferón gamma/administración & dosificación , Interferón gamma/efectos adversos , Masculino , Melfalán/administración & dosificación , Melfalán/efectos adversos , Persona de Mediana Edad , Terapia Neoadyuvante , Recurrencia Local de Neoplasia/cirugía , Radioterapia Adyuvante , Terapia Recuperativa , Sarcoma/radioterapia , Neoplasias de los Tejidos Blandos/radioterapia , Análisis de Supervivencia , Factor de Necrosis Tumoral alfa/administración & dosificación , Factor de Necrosis Tumoral alfa/efectos adversos
5.
Swiss Surg ; Suppl 2: 4-7, 1998.
Artículo en Francés | MEDLINE | ID: mdl-9757796

RESUMEN

BACKGROUND: The treatment of infra-renal abdominal aortic aneurysms (AAA) with endovascular stent-graft prostheses is receiving increasing attention as an alternative to major abdominal surgery. Numerous systems are under clinical investigations. We report our preliminary clinical results with the new Talent straight and bifurcated endografts. METHOD: We treated 5 patients with 3 straight and 2 bifurcated stent-grafts implanted by surgical femoral arteriotomies and placed under fluoroscopic guidance. Control CT and angiographic examinations were performed during an average follow-up of 5.3 months. RESULTS: In the first patient the procedure had to be converted to an open surgical operation to repo sition the distal end of the prosthesis. We had no mortality, or major systemic complication. Three patients had a postimplantation syndrome. All aneurysms showed a decreased size at 3 months, in spite of 3 small persisting leaks. CONCLUSION: The Talent endograft is safe, and efficacious in the endovascular treatment of AAA. This method requires a good cooperation between the vascular surgeon and the interventional radiologist. Learning curves influence preliminary results.


Asunto(s)
Aneurisma de la Aorta Abdominal/cirugía , Prótesis Vascular , Stents , Anciano , Aneurisma de la Aorta Abdominal/diagnóstico por imagen , Aortografía , Implantación de Prótesis Vascular , Femenino , Humanos , Masculino , Persona de Mediana Edad , Diseño de Prótesis , Falla de Prótesis , Reoperación , Tomografía Computarizada por Rayos X
6.
Eur J Pharmacol ; 351(2): 225-33, 1998 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-9687007

RESUMEN

Matrix metalloproteinases are zinc metalloenzymes involved in remodelling of the extracellular matrix. We compared the anti-invasive properties of a zinc ejector matrix metalloproteinase inhibitor with those of reference compounds (hydroxamic acid-based BB-94 and Ro-31-9790) which form inactive ternary complexes with the enzymes and the catalytic zinc. We show that the compound undecadenedioic acid bis-[[2-(3 H-imidazol-4-yl)-ethyl]-amide] (S 30372) is active against gelatinases, chelates zinc and exhibits enzymatic features compatible with the potential to extract zinc from gelatinases. We then used five invasive cell lines in the Matrigel invasion chamber assay (NIH-3T3 fibroblasts, Lewis lung carcinoma cells, EJ138 and J82 bladder carcinoma and HT1080 fibrosarcoma cells). With the exception of J82 cells which were unaffected by the three inhibitors, all remaining cells were substantially more sensitive to S 30372 in terms of maximal inhibition of invasion attained. This suggests that matrix metalloproteinase inhibitors with zinc chelating/ejecting properties may be more efficient in preventing tumor progression.


Asunto(s)
Quelantes/farmacología , Gelatinasas/antagonistas & inhibidores , Ácidos Hidroxámicos , Invasividad Neoplásica , Zinc , Células 3T3 , Animales , Quelantes/química , Ácidos Grasos Insaturados/química , Ácidos Grasos Insaturados/farmacología , Histamina/farmacología , Imidazoles/química , Imidazoles/farmacología , Metaloendopeptidasas/antagonistas & inhibidores , Ratones , Ratones Endogámicos BALB C , Fenilalanina/análogos & derivados , Fenilalanina/farmacología , Inhibidores de Proteasas/farmacología , Tiofenos/farmacología , Células Tumorales Cultivadas
7.
Swiss Surg ; (2): 62-6, 1996.
Artículo en Francés | MEDLINE | ID: mdl-8681110

RESUMEN

From August 91 to December 94, 20 external fixators were used for severely injured patients (avg. ISS 25.2). The fractures were essentially open book with or without lateral compression and vertical lesions. The indication for fixation was treatment of shock and stabilization in 8 cases, stabilization alone in 9 cases, and in 3 cases as complementary fixation after internal fixation of posterior lesions. The fixation of the pelvis was effective on the amount of blood loss. One acetabulum fracture required surgery, two patients had internal fixation for loss of reduction and two others for late pubic and posterior pain. The clinical results are good; they are more related to the severity of the initial lesion than to the mode of fixation or the quality of the reduction. No superficial sepsis or osteitis was observed in relation to the pins.


Asunto(s)
Fijadores Externos , Traumatismo Múltiple/cirugía , Huesos Pélvicos/lesiones , Adulto , Anciano , Pérdida de Sangre Quirúrgica/fisiopatología , Femenino , Estudios de Seguimiento , Fijación Interna de Fracturas/instrumentación , Curación de Fractura/fisiología , Humanos , Masculino , Persona de Mediana Edad , Traumatismo Múltiple/diagnóstico por imagen , Huesos Pélvicos/diagnóstico por imagen , Huesos Pélvicos/cirugía , Complicaciones Posoperatorias/diagnóstico por imagen , Complicaciones Posoperatorias/cirugía , Radiografía , Reoperación , Estudios Retrospectivos
8.
Swiss Surg ; (6): 311-3, 1995.
Artículo en Francés | MEDLINE | ID: mdl-8581819

RESUMEN

Ergot's derivatives are widely used in the treatment of migraine and in the prophylaxy of deep venous thrombosis in association with heparin. Clinical ergotism is rarely observed and can affect all the arteries, especially of the inferior limbs. Vasospasm of the peripheral arteries and collateral formation are specific findings on angiography. We report the illustrative case of a 38 years old woman hospitalized for a small bowel occlusion. She suffers from chronic migraine treated by ergotamine tartrate. During her hospitalization, she develops an acute ischemia of the lower limbs. An ergotism was clinically suspected and confirmed by Duplex sonography which demonstrate multiple vasospasm. Under iv sodium nitroprusside and peridural analgesia the spasm resolved in 24 hours. The control Duplex sonography confirm the normality of the lower limb arteries. This examination modality allow a non-invasive diagnosis and evolution control of arteriospasm.


Asunto(s)
Ergotamina/efectos adversos , Ergotismo/diagnóstico por imagen , Pierna/irrigación sanguínea , Trastornos Migrañosos/tratamiento farmacológico , Ultrasonografía Doppler Dúplex , Adulto , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Ergotamina/administración & dosificación , Femenino , Humanos , Isquemia/inducido químicamente , Isquemia/diagnóstico por imagen
11.
Int J Pept Protein Res ; 43(5): 496-504, 1994 May.
Artículo en Inglés | MEDLINE | ID: mdl-8070974

RESUMEN

The major tyrosine protein kinase, HPK40, isolated from HL-60, the preparation of which is described elsewhere (Ernould, A.P., Ferry, G., Barret, J.M., Genton, A. and Boutin, J.A., Eur. J. Biochem., 214, 503-514), was investigated as to its specificity on a number of peptides and proteins. It was found that HPK40 can phosphorylate histones (except histone H4), casein, acid-treated enolase, actin and tubulin but not calmodulin. Phosphorylation specificity of HPK40 was investigated using over a hundred peptidic structures. HPK40 is not related to the 'src' family and does not phosphorylate efficiently either the tetrapeptide NEYT derived from the pp60src autophosphorylation domain or the corresponding peptide RRsrc, RRLIED-NEYTARG. VALYDYESR from the SH3 domain of pp60c-src is recognized as a substrate with a high phosphorylation level. DEDYIQD, derived from the phosvitin/casein kinase II, was also highly phosphorylated. In order to determine the minimal recognition sequence of HPK40, the phosphorylation of about 60 dito tetrapeptides was investigated. Some of the tetrapeptides, such as *EEYE and NEYE, were well phosphorylated. Even some tripeptides, such as EYE, DYM, TYS and KYE, were recognized by HPK40, while none of the tested dipeptides was recognized as substrate. Sequences of peptides from DRVYHPF (angiotensin), LEEEEEAYGWMDF (minigastrin) and QEEYSAM (from H-ras1) were examined as substrates. The presence of one or several acidic residues on the N alpha-side of tyrosine residue was identified as the only apparently favorable determinant.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Leucemia Promielocítica Aguda/enzimología , Proteínas Tirosina Quinasas/metabolismo , Secuencia de Aminoácidos , Humanos , Datos de Secuencia Molecular , Fosforilación , Fosfotransferasas/metabolismo , Especificidad por Sustrato , Células Tumorales Cultivadas
12.
Helv Chir Acta ; 60(4): 507-8, 1994 Apr.
Artículo en Francés | MEDLINE | ID: mdl-8034527

RESUMEN

Caval reconstruction during orthotopic liver transplantation is usually achieved by two end-to-end anastomoses and extracorporeal veno-venous bypass. We report our preliminary experience with a new technique by lateral clamping of the recipient's cava and a side-to-side caval anastomosis without by-pass. This new technique appears safe and shortens the operative time.


Asunto(s)
Anastomosis Quirúrgica/métodos , Trasplante de Hígado/métodos , Vena Cava Inferior/cirugía , Humanos , Ligadura
14.
Int J Oncol ; 4(6): 1243-50, 1994 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21567044

RESUMEN

This study was aimed to characterize the reversing activity of S16209 and S16317, two new dihydropyridines with low affinity for calcium channels. In vivo, S16209 (75 mg/kg) and S16317 (25 mg/kg) potentiate the antitumor activity of vincristine (VCR) in VCR-resistant leukemia bearing mice. In vitro, a complete sensitization to adriamycin (ADR) or VCR is obtained with 2.5 muM of S16209 in S1/tMDR and KB-A1 cells and with 2.5 muM of S16317 in S1/tMDR and P388/ADR-10 cells. These two compounds are also more potent than verapamil and cyclosporin A in increasing actinomycin-D cytotoxicity in DC-3F/AD cells. In the presence of ADR or VCR, a 4 h co-incubation followed by a post-incubation of 20 h with 2.5 muM S16209 is sufficient to completely overcome the resistance of human KB-A1 and S1/tMDR cells to these cytotoxic drugs. S16209 and S16317 increase ADR accumulation in resistant cells, and completely inhibit the photolabeling of P-gp by [H-3]azidopine at 100 and 10 muM, respectively, suggesting that the reversing activity of these two compounds is mainly due to a specific inhibition of the P-gp mediated efflux of cytotoxic drugs.

15.
Biochem Pharmacol ; 46(3): 439-48, 1993 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-8347167

RESUMEN

Tyrosine protein kinases (TPKs) play a major role in the transformation of cells. They are currently used as molecular targets for new generations of anticancer compounds. Numerous TPKs have been described from various tissues using either classical molecular biochemical techniques or cloning strategies. As a natural extension of these discoveries, a large number of "specific" inhibitors have been described in the literature. The major problem with these inhibitors is that there is no simple way to compare their specificity and/or selectivity from one report to another. We have set up a simple, straightforward technique to compare the inhibitory potency of 14 classical inhibitors towards six well-described and at least partially purified protein kinases. This technique is based on a new assay, easy to carry out and non-restrictive in terms of the type of protein substrate used. It permits direct comparisons between the results obtained from various sources. Data obtained showed that, when assessed in this integrated system, specificity and selectivity of many "classical" inhibitors are often weak, thus demonstrating that a universal technique such as ours is essential for the molecular screening of new protein kinase inhibitors. Compounds showing specificity for this panel of protein kinases will be more easily targeted to some defined types of oncogene and of transformed cells.


Asunto(s)
Inhibidores Enzimáticos/farmacología , Péptidos y Proteínas de Señalización Intracelular , Inhibidores de Proteínas Quinasas , Alcaloides/farmacología , Animales , Proteínas Portadoras/farmacología , Humanos , Hidroquinonas/farmacología , Péptidos y Proteínas de Señalización Intercelular , Cinética , Ratones , Péptidos/metabolismo , Proteínas Quinasas/aislamiento & purificación , Quercetina/farmacología , Ratas , Estaurosporina , Suramina/farmacología
16.
Eur J Biochem ; 214(2): 503-14, 1993 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-8513800

RESUMEN

The major tyrosine protein kinase from HL60 (a human non-differentiated promyelocytic cell line) has been purified almost to homogeneity as judged by silver-stained SDS/PAGE. The procedure involved four chromatographic steps: DEAE-Sepharose, casein-agarose, cibacron-blue--agarose and hexyl-agarose. The purification resulted in more than 1000-fold enrichment in angiotensin II phosphorylation activity. A gel-sizing experiment, labeling with [35S]ATP[gamma s] and autophosphorylation of the enzyme in the presence of [gamma-32P]ATP, all led to the identification of a single protein species with a molecular mass of about 40 kDa. Western blot experiments showed that this protein does not belong to the src family and is not related to the abl and fes oncogene products. Phosphorylation of angiotensin II and casein by this 40-kDa human promyelocytic kinase was stimulated by high ionic strength especially from class IA metal salts. The Km for ATP was 2 microM and the Vmax 3.1 nmol.min-1.mg-1 using angiotensin II as a substrate. The kinase requires the presence of either Mn2+ or Mg2+ for full activity and utilizes ATP or dATP but not GTP as phosphate donor. Based on numerous biochemical observations, it was possible to demonstrate that kinase is different from any other tyrosine protein kinases described in the literature. This 40-kDa protein was used as a molecular tool for testing some tyrosine protein kinase inhibitors described in the literature. It is one of the rare tyrosine protein kinases purified from human cancer cells to date.


Asunto(s)
Leucemia Promielocítica Aguda/enzimología , Proteínas Tirosina Quinasas/aislamiento & purificación , Adenosina Trifosfato/análogos & derivados , Adenosina Trifosfato/metabolismo , Angiotensina II/metabolismo , Unión Competitiva , Western Blotting , Caseínas/metabolismo , Guanosina Trifosfato/metabolismo , Humanos , Cinética , Magnesio/farmacología , Manganeso/farmacología , Metales/farmacología , Concentración Osmolar , Fosforilación , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Proteínas Tirosina Quinasas/metabolismo , Células Tumorales Cultivadas
17.
Chem Biol Interact ; 86(1): 17-27, 1993 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8431962

RESUMEN

Tyrosine as well as serine/threonine protein kinase inhibitors have potentially two sites of interaction with their targets: the protein-substrate binding site and the ATP binding site. The latter could be modelized by measuring the capacity of protein kinase inhibitors to inhibit ATPase activities. In order to do so, we assess a novel, highly sensitive HPLC method based on hydrophilic separation of [gamma-32P]ATP and [32P]Pi. The novel assay is presented. Furthermore, the potency of 13 protein kinase inhibitors was tested on two types of ATPase, namely: apyrase and partially purified liver mitochondria F1-ATPase. The method described for the assay of ATPase can be used with almost any type of enzyme catalyzing this activity. Only cibacron blue and suramin show interesting capacities in inhibiting these ATPase activities pointing out that several widely used protein kinase inhibitors are at least somewhat specific in that they do not inhibit these two ATPases.


Asunto(s)
Adenosina Trifosfatasas/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas , Adenosina Trifosfato/aislamiento & purificación , Adenosina Trifosfato/metabolismo , Animales , Apirasa/antagonistas & inhibidores , Membrana Celular/enzimología , Cromatografía Líquida de Alta Presión , Relación Dosis-Respuesta a Droga , Cinética , Leucemia P388/enzimología , Mitocondrias Hepáticas/enzimología , Fosfatos/aislamiento & purificación , Fosfatos/metabolismo , Proteínas Tirosina Quinasas/antagonistas & inhibidores , ATPasas de Translocación de Protón/antagonistas & inhibidores , Ratas , Suramina/administración & dosificación , Suramina/farmacología , Triazinas/administración & dosificación , Triazinas/farmacología
18.
J Chromatogr ; 583(2): 137-43, 1992 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-1478977

RESUMEN

A new HPLC method has been developed to assay tyrosine protein kinase activity. Using hydrophilic interaction chromatography, it is possible to resolve the four components of the incubation medium: substrate peptide, [32P]phosphorylated peptide, unreacted [gamma-32P]ATP, and 32P-labelled inorganic phosphate. ATP interacts so strongly with the stationary phase material that it can be removed selectively from the incubation medium with solid-phase extraction cartridges packed with the same type of material. The three remaining components of interest can then be resolved by reversed-phase or hydrophilic interaction HPLC. This procedure permits the evaluation of almost every type of peptide as a substrate of tyrosine protein kinase.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Proteínas Tirosina Quinasas/metabolismo , Secuencia de Aminoácidos , Línea Celular , Gastrinas/metabolismo , Humanos , Datos de Secuencia Molecular , Proteínas de Neoplasias/metabolismo , Fosforilación , Espectrofotometría Ultravioleta , Especificidad por Sustrato
20.
Biochem Pharmacol ; 44(9): 1707-15, 1992 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-1360210

RESUMEN

A new triazinoaminopiperidine derivative, Servier 9788 (S9788), was investigated for its ability to increase Adriamycin (ADR) accumulation and retention in two rodent (P388/ADR and DC-3F/AD) and three human (KB-A1, K562/R and COLO 320DM) cell lines displaying the P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) phenotype. Depending on the cell line S9788 was shown to be two to five times more active and five to 15 times more potent than Verapamil (VRP) in increasing ADR accumulation in resistant cells. ADR retention in KB-A1 cells maintained in a concentration of 10 microM S9788 was twice that in VRP-treated cells, and similar to that measured in the untreated sensitive KB-3-1 cells. Although 5 microM S9788 and 50 microM VRP gave the same values of ADR uptake in KB-A1 cells, S9788 was shown to induce a greater ADR retention following cell wash and post-incubation in resistance modifier- and ADR-free medium. Taking into account that S9788 had no effects on ADR accumulation and retention in sensitive KB-3-1 cells, it can be suggested that S9788 inhibits specifically the P-gp dependent ADR efflux, and in a manner less reversible than that observed with VRP. Moreover, [3H]azidopine photolabeling of P-gp, in P388/ADR plasma membranes, was completely inhibited by 100 microM S9788. Although S9788, as VRP, had no effect on the cell cycle of P388 cells, 5 microM S9788 increased 700-fold the efficacy of ADR to block P388/ADR cells in the G2+M phase of the cell cycle. Together, these results show that the sensitization, by S9788, of cell lines resistant to ADR is mainly due to an increase in ADR accumulation and retention, leading to an increase in the number of resistant cells blocked in the G2+M phase.


Asunto(s)
Antineoplásicos/farmacología , Doxorrubicina/farmacocinética , Glicoproteínas de Membrana/fisiología , Piperidinas/farmacología , Triazinas/farmacología , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/metabolismo , Animales , Azidas/metabolismo , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/metabolismo , Ciclo Celular/efectos de los fármacos , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Células Cultivadas , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/metabolismo , Cricetinae , Cricetulus , Dihidropiridinas/metabolismo , Resistencia a Medicamentos/fisiología , Citometría de Flujo , Fluorescencia , Humanos , Cinética , Leucemia P388/tratamiento farmacológico , Leucemia P388/metabolismo , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/metabolismo , Pulmón , Glicoproteínas de Membrana/metabolismo , Ratones , Sensibilidad y Especificidad , Tritio , Células Tumorales Cultivadas , Verapamilo/farmacología
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