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1.
Dig Dis Sci ; 58(8): 2399-405, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23525734

RESUMO

BACKGROUND: Effective and tolerable chemotherapy with gemcitabine and cisplatin for advanced biliary tract cancer (BTC) has been established recently. However, overall prognosis is still poor, and additional therapeutic approaches are needed for patients with locally advanced, irresectable and/or pretreated tumors. Hepatic arterial infusion (HAI) of chemotherapy represents a safe and well-established treatment modality, but data on its use in patients with BTC are still sparse. METHODS: Patients with irresectable BTC predominant to the liver were included in a prospective, open phase II study investigating HAI provided through interventionally implanted port catheters. Intraarterial chemotherapy consisted of biweekly oxaliplatin (O) 85 mg/m(2) and folinic acid (F) 170 mg/m(2) with 5-FU (F) 600 mg/m(2). RESULTS: Between 2004 and 2010, 37 patients were enrolled. A total of 432 cycles of HAI were applied with a median of 9 (range 1-46) cycles. Objective response rate was 16 %, and tumor control was achieved in 24 of 37 (65 %) patients. Median progression-free survival was 6.5 months (range 0.5-26.0; 95 % CI 4.3-8.7), median overall survival was 13.5 (range 0.9-50.7; 95 % CI 11.1-15.9) months. The most frequent adverse event was sensory neuropathy grade 1/2 in 10/14 patients. CONCLUSIONS: Using a minimal invasive technique, repetitive HAI with OFF is feasible and results in clinically relevant tumor control with low toxicity in patients with liver predominant advanced BTC.


Assuntos
Neoplasias do Sistema Biliar/tratamento farmacológico , Fluoruracila/uso terapêutico , Leucovorina/uso terapêutico , Fígado/irrigação sanguínea , Compostos Organoplatínicos/uso terapêutico , Adulto , Idoso , Antineoplásicos/administração & dosagem , Antineoplásicos/uso terapêutico , Esquema de Medicação , Quimioterapia Combinada , Feminino , Fluoruracila/administração & dosagem , Humanos , Leucovorina/administração & dosagem , Masculino , Pessoa de Meia-Idade , Compostos Organoplatínicos/administração & dosagem , Oxaliplatina
2.
Nature ; 469(7329): 189-93, 2011 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-21228872

RESUMO

As silicon is the basis of conventional electronics, so strontium titanate (SrTiO(3)) is the foundation of the emerging field of oxide electronics. SrTiO(3) is the preferred template for the creation of exotic, two-dimensional (2D) phases of electron matter at oxide interfaces that have metal-insulator transitions, superconductivity or large negative magnetoresistance. However, the physical nature of the electronic structure underlying these 2D electron gases (2DEGs), which is crucial to understanding their remarkable properties, remains elusive. Here we show, using angle-resolved photoemission spectroscopy, that there is a highly metallic universal 2DEG at the vacuum-cleaved surface of SrTiO(3) (including the non-doped insulating material) independently of bulk carrier densities over more than seven decades. This 2DEG is confined within a region of about five unit cells and has a sheet carrier density of ∼0.33 electrons per square lattice parameter. The electronic structure consists of multiple subbands of heavy and light electrons. The similarity of this 2DEG to those reported in SrTiO(3)-based heterostructures and field-effect transistors suggests that different forms of electron confinement at the surface of SrTiO(3) lead to essentially the same 2DEG. Our discovery provides a model system for the study of the electronic structure of 2DEGs in SrTiO(3)-based devices and a novel means of generating 2DEGs at the surfaces of transition-metal oxides.

3.
B-ENT ; 5(3): 189-93, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19902858

RESUMO

OBJECTIVES: Castleman's disease is an uncommon disease of benign lymph node hyperplasia primarily affecting the mediastinum, with the head and neck region being the second most common site. CASE REPORT: A 27-year-old woman was admitted to our department due to a left lateral cervical mass. After a complete clinical and imaging examination, a neck dissection was performed, in which a mass, size 3.5 x 2.7 x 4.5 cm, was excised. The patient was diagnosed with Castleman's disease of the neck after histopathological examination. CONCLUSIONS: The diagnosis of Castleman's disease is always a clinical challenge, as the patient commonly presents with nonspecific signs and symptoms resembling other lymphatic diseases. Consequently, Castleman's disease should be in the differential diagnosis of congenital, inflammatory, or neoplastic cervical alterations. A review of literature, including histopathological characteristics, differential diagnosis, and treatment options is also presented.


Assuntos
Hiperplasia do Linfonodo Gigante/diagnóstico , Pescoço , Adulto , Hiperplasia do Linfonodo Gigante/terapia , Diagnóstico Diferencial , Feminino , Humanos
4.
Nuklearmedizin ; 45(4): 177-84, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16964344

RESUMO

PURPOSE: Before locally ablative treatment of colorectal liver metastases, patients have to be carefully evaluated to decide whether this is the adequate therapy. In this study we determined the value of FDG-PET in comparison to conventional staging procedures. PATIENTS, METHODS: In 68 consecutive patients referred for laser induced thermotherapy (LITT) of liver metastases from colorectal cancer, pretherapeutic staging with conventional imaging (thoracic and abdominal CT, liver MRI, chest X-ray) and FDG-PET was performed. The examinations were analysed separately and blinded. Based on the staging information, therapeutic decisions were made by an interdisciplinary review board according to a standardized algorithm. The results were compared between conventional imaging and FDG-PET, and were validated by clinical follow up data and histopathology, respectively. RESULTS: On FDG-PET 210 lesions were interpreted as tumour manifestations. 48 of these were not seen on conventional imaging (true positive, n = 46). In contrast, 24 lesions were visualized by conventional imaging only (true positive, n = 12). Compared to conventional imaging, discrepant findings on FDG-PET led to treatment modifications in 25 patients (37%); these were correct in 20/25 patients. According to the actual treatment course, the inadequate treatment modifications in the remaining 5 patients were avoided by further diagnostic procedures (i.e. biopsies). CONCLUSION: In the evaluation of patients with known liver metastases from colorectal cancer before LITT, FDG-PET depicts relevant findings subsidiary to conventional imaging and thus is of high value for therapeutic decision making.


Assuntos
Neoplasias Colorretais/patologia , Fluordesoxiglucose F18 , Hipertermia Induzida , Neoplasias Hepáticas/cirurgia , Neoplasias Hepáticas/terapia , Humanos , Lasers , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/secundário , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Estudos Retrospectivos , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X
5.
Onkologie ; 27(5): 506-11, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15585984

RESUMO

Progress in surgery and adjuvant therapy has markedly improved local control and survival rates in patients with primary, non-metastatic rectal cancer. However, the prognosis of patients with locally recurrent disease is still poor, and a realistic chance for repeated treatment with curative intent is still restricted to the minority of cases. Therefore, effective palliation of symptoms and preservation of a good quality of life are the major goals of therapy for most patients with local recurrence of rectal cancer. Here we give a short overview on the options available for the treatment of pelvic recurrence of rectal cancer, with special focus on adjunctive regional pelvic radiofrequency hyperthermia.


Assuntos
Hipertermia Induzida/métodos , Recidiva Local de Neoplasia/terapia , Pelve , Neoplasias Retais/terapia , Terapia Combinada/métodos , Humanos , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/radioterapia , Recidiva Local de Neoplasia/cirurgia , Neoplasias Retais/tratamento farmacológico , Neoplasias Retais/radioterapia , Neoplasias Retais/cirurgia , Resultado do Tratamento
6.
Ann Clin Biochem ; 40(Pt 5): 534-41, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-14503991

RESUMO

BACKGROUND: Hyperhomocysteinaemia is an independent risk factor in the development of cardiovascular disease. Although homocysteine has been shown to affect endothelial cell function, the mechanisms by which it induces disease states are still poorly understood. Here, we report the ability of homocysteine to influence inflammatory cytokine/chemokine production by human saphenous vein endothelial cells, peripheral blood monocytes and monocyte-derived macrophages. METHODS: Human saphenous vein endothelial cells, peripheral blood monocytes and monocyte-derived macrophages were treated with homocysteine (0.1-5 mmol/L) for 4 and/or 24h. Tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6 and IL-8 production was measured in the cell culture media using commercially available enzyme-linked immunosorbent assays. RESULTS: Interleukin-6 production by human saphenous vein endothelial cells was significantly stimulated following a 24-h treatment with homocysteine, whilst IL-8 concentrations were inhibited after both 4- and 24-h treatments. Homocysteine was also found to stimulate IL-1beta production by human peripheral blood monocytes and TNF-alpha production by monocyte-derived macrophages. CONCLUSIONS: Overall, results from this study suggest that homocysteine alters the profile of cytokine/chemokine production by endothelial cells and macrophages. This altered profile may be important in the inflammatory events that initiate or enhance the development of atherosclerotic lesions.


Assuntos
Citocinas/biossíntese , Células Endoteliais/efeitos dos fármacos , Homocistina/farmacologia , Monócitos/efeitos dos fármacos , Tamanho Celular/efeitos dos fármacos , Células Cultivadas , Células Endoteliais/metabolismo , Humanos , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Monócitos/citologia , Monócitos/metabolismo , Veias
7.
Nephrol Dial Transplant ; 15(2): 205-11, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10648666

RESUMO

BACKGROUND: Ultrasound, genetic and clinical correlations are available for ADPKD-1, but lacking for ADPKD-2. The present study was carried out to address: (i) the age-related diagnostic usefulness of ultrasound compared with genetic linkage studies; (ii) the age-related incidence and prevalence of relevant symptoms and complications; and (iii) the age and causes of death in patients with ADPKD-2. METHODS: Two hundred and eleven alive subjects, from three ADPKD-2 families at 50% risk, were evaluated by physical examination, consultation of hospital records, biochemical parameters, ultrasound and with genetic linkage and DNA mutation analyses. Nineteen deceased and affected family members were also included in the study. RESULTS: Of the 211 alive members, DNA linkage studies and direct mutation analyses showed that 106 were affected and 105 were not. Ultrasound indicated 94 affected, 108 not affected and nine equivocal results in nine children under the age of 15. For all ages, the false-positive diagnostic rate for ultrasound was 7.5% and the false-negative rate was 12.9%. The difference between ultrasound and DNA findings was most evident in children aged 5-14 years where the ultrasound was correct in only 50% and wrong or inconclusive in the remaining 50%. The mean age of the 106 alive, ADPKD-2 genetically affected patients was 37.9 years (range: 6-66 years). Among them, 23.5% had experienced episodes of renal pain, 22.6% were treated for hypertension, 22.6% had experienced at least one urinary tract infection, 19.8% had nephrolithiasis, 11.3% had at least one episode of haematuria, 9.4% had asymptomatic liver cysts, 7.5% had developed chronic renal failure and 0.9% had reached end-stage renal failure. Of the 19 deceased members, nine died before reaching end-stage renal failure at a mean age of 58.7 years (range: 40-68 years), mainly due to vascular complications, while the remaining 10 died on haemodialysis at a mean age of 71.4 years (range: 66-82 years). CONCLUSIONS: DNA analysis is the gold standard for the diagnosis of ADPKD-2, especially in young people. Ultrasound diagnosis is highly dependent on age. Under the age of 14, ultrasound is not recommended as a routine diagnostic procedure, but ultrasound becomes 100% reliable in excluding ADPKD-2 in family members at 50% risk, over the age of 30. ADPKD-2 represents a mild variant of polycystic kidney disease with a low prevalence of symptoms and a late onset of end-stage renal failure.


Assuntos
Rim Policístico Autossômico Dominante/diagnóstico por imagem , Rim Policístico Autossômico Dominante/genética , Injúria Renal Aguda/etiologia , Adolescente , Adulto , Envelhecimento/fisiologia , Causas de Morte , Criança , Pré-Escolar , DNA/genética , Análise Mutacional de DNA , Reações Falso-Negativas , Reações Falso-Positivas , Feminino , Ligação Genética , Humanos , Falência Renal Crônica/etiologia , Hepatopatias/etiologia , Masculino , Pessoa de Meia-Idade , Rim Policístico Autossômico Dominante/classificação , Rim Policístico Autossômico Dominante/complicações , Ultrassonografia/normas , Doenças Urológicas/etiologia
8.
Br J Haematol ; 105(4): 1055-65, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10554820

RESUMO

We describe two British families with similar, dominantly-inherited, temperature-related variants of hereditary stomatocytosis, consistent with the original description of 'cryohydrocytosis'. The cells show a 5-6-fold increase in passive permeability at 37 degrees C with abnormal intracellular Na and K levels at 15-20 and 60-65 mmol/(l cells) respectively. Marked temperature effects were evident: lysis of red cells on storage in the cold was blatant and when whole heparinized blood was stored at room temperature, K accumulated in the plasma, producing 'pseudohyperkalaemia'. Studies of the temperature dependence of passive permeability showed that the minimum in the passive permeability, which is seen in normal cells at 8-10 degrees C, was shifted up to 23 degrees C in these abnormal cells, such that the permeability at 0 degrees C exceeded that at 37 degrees C. The abnormal temperature dependence in these genetically abnormal red cells strongly resembles that seen in normal cells when suspended in media in which either Na or Cl has been replaced by an organic cation or anion: it could be said these cells had a genetic mutation that somehow rendered the cell resistant to the stabilizing action of NaCl at low temperatures.


Assuntos
Anemia Hemolítica Congênita/genética , Anemia Hemolítica Congênita/epidemiologia , Anemia Hemolítica Congênita/metabolismo , Permeabilidade da Membrana Celular/fisiologia , Temperatura Baixa , Membrana Eritrocítica/fisiologia , Volume de Eritrócitos , Feminino , Humanos , Masculino , Linhagem , Potássio/metabolismo , Sódio/metabolismo , ATPase Trocadora de Sódio-Potássio , Temperatura , Reino Unido/epidemiologia
9.
Biochem Pharmacol ; 57(11): 1311-9, 1999 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-10230775

RESUMO

The effect of the industrial chemical, hydrazine (4-12 mM), on methionine synthase (EC 2.1.1.13) activity and levels of the sulphur amino acids homocysteine, cysteine, and taurine as well as GSH were investigated in vitro in isolated rat hepatocyte suspensions and monolayers in order to explain some of the adverse in vivo effects of hydrazine. None of the concentrations of hydrazine were overtly cytotoxic in hepatocyte suspensions (measured as lactate dehydrogenase [LDH] leakage) after 3 hr. However, after 24 hr in culture cells treated with 12 mM, hydrazine showed a significant increase in LDH leakage. Methionine synthase activity was reduced by hydrazine (8 and 12 mM) in suspensions (by 45 and 55%, after 3 hr) and monolayers (12 mM; 65-80% after 24 hr). This was not due to nitric oxide production and the inhibitor of nitric oxide synthase, Nomega-nitro-L-arginine, failed to protect against the hydrazine-induced loss of ATP and GSH and the reduction in urea synthesis at 24 hr. Homocysteine export was increased by 6 mM hydrazine, and total taurine content of treated cells was increased by 12 mM hydrazine. Thus, hydrazine was found to have several important and possibly deleterious effects on some parts of the sulphur amino acid pathway.


Assuntos
5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/metabolismo , Aminoácidos Sulfúricos/metabolismo , Hidrazinas/farmacologia , Vitamina B 12/metabolismo , Animais , Carcinógenos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Meios de Cultura/metabolismo , Cisteína/metabolismo , Citosol/metabolismo , Inibidores Enzimáticos/farmacologia , Homocisteína/metabolismo , Fígado , Masculino , Nitroarginina/farmacologia , Ratos , Ratos Wistar , Taurina/metabolismo
10.
Anticancer Res ; 18(1B): 587-93, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9568182

RESUMO

The identification of prognostic factors influencing local control and survival of patients with nasopharyngeal cancer (NPC) might help in pointing out those patients who would probably benefit from primary treatment. A series of 137 Greek patients with locally advanced NPC treated with chemotherapy and/or radiation were analyzed for significant prognostic factors influencing complete response (CR) to treatment, time to progression (TTP) and overall survival (OS). After the completion of treatment, 92 (67%) patients achieved CR. Logistic regression analysis revealed that only T classification was significant for CR (p = 0.0058). After a median follow-up of 5 years, 66 (48%) patients demonstrated tumor progression and 64 (47%) died. Median TTP was 25.8 months (range, 0.3-118+) and median survival 58.3 months (range, 0.3-124+). Cox proportional hazards model identified age (p = 0.024) and T classification (p = 0.009) as significant factors for TTP. These two factors were also found to be significant for OS (p = 0.005 and p = 0.013, respectively). The present study has shown that major prognostic factors influencing the outcome of our patients with NPC are similar to those reported in recent Chinese studies. These prognostic factors may be used as stratification factors in randomized clinical trials.


Assuntos
Neoplasias Nasofaríngeas/terapia , Adolescente , Adulto , Fatores Etários , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Nasofaríngeas/tratamento farmacológico , Neoplasias Nasofaríngeas/mortalidade , Neoplasias Nasofaríngeas/radioterapia , Prognóstico , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
11.
Anticancer Res ; 18(6B): 4655-60, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9891536

RESUMO

Primary extranodal NHL of the head and neck (HN-NHL) accounts for 10-20% of all cases of NHL. Despite their frequency, the natural history and biological behaviour of these lymphomas is poorly understood. In this study we analysed the data 116 cases of HN-NHL. There were 65 males and 51 females with a median age of 56 years. The distribution among different anatomical sites was: tonsils 56 cases (48.3%), nasopharynx 15 (12.9%), mandible/gingiva 9 (7.8%), hard palate 7 (6%), parotis 6 (5.2%), nasal cavity 6 (5.2%), hypopharynx/larynx 6 (5.2%), thyroid 5 (4.3%), ocular adnexa 4 (3.5%), paranasal sinuses 2 (1.7%). The patients were treated with radiotherapy alone (14 cases), combined chemotherapy (52 cases) and combined modality (50 cases). According to the WF histological classification 73 cases (62.9%) had intermediate, 32 (27.6%) high and 11 (9.5%) low grade. Patients were separated in two groups: Tonsillar NHL (56 cases) and NHL of all other sites (non-tonsillar group-60 cases). A comparison between the two groups showed that there was no statistically significant difference with respect to age, sex, and histological subtypes. Also treatment response was similar (82.1% for the tonsillar vs 83.3% for the non-tonsillar). The two groups differed in stage distribution, survival and pattern of relapse. Stage I was more frequent in the non-tonsillar NHL (60%) in contrast to tonsillar NHL where stage II was more prominent (51.8%). Median survival was 86 months for the tonsillar while it has not been reached yet for the non-tonsillar patients. Patients in stage I and stage II of the non-tonsillar group had better survival compared to stages I and II of the tonsillar patients. Finally GI tract was a common site of relapse in the tonsillar group while a considerable number in CNS relapses were observed in the non-tonsillar group. We concluded that HN-NHL constitutes a heterogeneous group of patients. Tonsillar lymphomas represent a distinct group with some special clinicopathological findings.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/radioterapia , Linfoma não Hodgkin/tratamento farmacológico , Linfoma não Hodgkin/radioterapia , Adulto , Terapia Combinada , Ciclofosfamida/administração & dosagem , Intervalo Livre de Doença , Doxorrubicina/administração & dosagem , Epirubicina/administração & dosagem , Feminino , Grécia , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Hidrocortisona/administração & dosagem , Linfoma não Hodgkin/mortalidade , Linfoma não Hodgkin/patologia , Masculino , Metotrexato/administração & dosagem , Metilprednisolona/administração & dosagem , Pessoa de Meia-Idade , Mitoxantrona/administração & dosagem , Análise Multivariada , Estadiamento de Neoplasias , Prednisolona/administração & dosagem , Prednisona/administração & dosagem , Recidiva , Taxa de Sobrevida , Fatores de Tempo , Vincristina/administração & dosagem
12.
J Pept Sci ; 3(4): 291-8, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9262648

RESUMO

Lipid mimetics, synthetic molecules that resemble natural lipids either structurally or functionally, have been developed as potential medicinal substances. They have been successfully applied in the development of drug and peptide delivery systems and for the development of inhibitors or lipid metabolizing enzymes. Phospholipase A2 is considered to be involved as the rate-limiting step in the production of lipid mediators of inflammatory responses and, as such, it has been a target for drug design. A series of lipid mimetics including lipopeptides, amides and alcohols of lipidic alpha-amino acids, have been tested by bulk and monolayer assay techniques. The findings suggested the direct interaction of the tested compounds with porcine pancreatic phospholipase A2. The inactivation of the enzyme occurred in a competitive manner. The most active compound I (2-amino-N-hexadecyl-L-hexanamide) showed an apparent IC50 of 12 microM and inhibitory power Z = 13 in the monolayer assay.


Assuntos
Inibidores Enzimáticos/síntese química , Lipídeos/síntese química , Lipoproteínas/síntese química , Peptídeos/síntese química , Animais , Inibidores Enzimáticos/química , Lipídeos/química , Lipoproteínas/química , Espectroscopia de Ressonância Magnética , Mimetismo Molecular , Pâncreas/enzimologia , Peptídeos/química , Fosfolipases A/antagonistas & inibidores , Fosfolipases A2 , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Suínos
13.
Ann Oncol ; 8(5): 451-5, 1997 May.
Artigo em Inglês | MEDLINE | ID: mdl-9233524

RESUMO

BACKGROUND: Paclitaxel has been demonstrated to have significant activity in recurrent or metastatic head and neck cancer (HNC). In addition, the combination of paclitaxel and cisplatin is active in untreated patients with inoperable HNC. Substitution of carboplatin for cisplatin allows the treatment to be delivered on an outpatient basis. PURPOSE OF THE STUDY: To evaluate the activity and toxicity of the combination of paclitaxel by three-hour infusion and carboplatin as first-line chemotherapy in patients with recurrent or metastatic HNC. PATIENTS AND METHODS: From March 1994 until August 1996, 49 patients with recurrent or metastatic HNC were treated with paclitaxel (200 mg/m2, by three-hour infusion) followed by carboplatin at an AUC of 7 mg.min/ml, every four weeks. G-CSF was administered prophylactically on days 2 to 12 of each cycle. There were 41 men and 8 women with a median age of 57 years (range 23-73). The majority of the patients were symptomatic and they had recurrent disease locoregionally. Fourteen patients had nasopharyngeal cancer (NPC) and 35 had squamous cell cancers of other areas of the head and neck region (non-NPC). RESULTS: At the completion of treatment, two patients with NPC demonstrated complete and six partial responses for an overall response rate of 57% (95% CI 29%-82%). Among patients with non-NPC, the response rate was 23% (95% CI 9%-37%). After a median follow up period of 15 months, the median time to progression was 4.3 months in the non-NPC group and 16.5 months in the NPC group. At the time of the analysis, median survival had not been reached in NPC while it was 7.3 months in non-NPC patients. Grade 3-4 toxicities included anemia (2%) and leukopenia, thrombocytopenia, stomatitis, nausea/vomiting and diarrhea (4% each). CONCLUSIONS: The combination of paclitaxel and carboplatin appears to be well tolerated but only moderately active in patients with advanced non-NPC of the head and neck region. However, its activity appears promising in NPC and deserves further investigation.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias Nasofaríngeas/tratamento farmacológico , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Carboplatina/administração & dosagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Paclitaxel/administração & dosagem
14.
Sci Total Environ ; 193(1): 27-35, 1996 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-9111768

RESUMO

Ten pesticides: aldicarb, aldicard sulfone, aldicarb oxide, carbofuran, propoxur, methomyl, diuron, linuron, alachlor and parathion-methyl, found as water pollutants in Cyprus, were evaluated for their genotoxicity potential with the Mutatox test, both directly and after exogenous activation with S9 hepatic enzymes. A dark variant (M 169) of the Photobacterium phosphoreum was used as the test organism. Trials were undertaken in triplicate using ground-water spiked with pesticides solutions at testing concentration theoretically corresponding to acute effects of 0.004%, up to a maximum of 2%. All tested pesticides were found to be 'suspect genotoxic' directly and after S-9 activation, except for Alachlor which after S-9 activation was found to be 'genotoxic' at 30 micrograms/l. Among the ten pesticides Linuron was found to be 'suspect genotoxic' after S-9 activation at the lowest concentration, i.e. 2 micrograms/l. Genotoxicity after activation with S-9 was demonstrated at a concentration 1-3 orders of magnitude lower than the respective concentration for direct genotoxic effects. Moreover, genotoxicity after S-9 was developed at levels where the acute toxic effects (Microtox) were 'non measurable' to 'negligible'. The investigation of possible genotoxic effects provides essential information on the impacts of pesticides on the Ecosystem and can contribute to the selection of pesticides with the least possible effects.


Assuntos
Dano ao DNA , Praguicidas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Carbamatos , Chipre , DNA/biossíntese , DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Água Doce , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/genética , Herbicidas/toxicidade , Inseticidas/toxicidade , Dose Letal Mediana , Fígado/enzimologia , Testes de Mutagenicidade , Compostos Organotiofosforados , Controle de Pragas , Photobacterium/efeitos dos fármacos , Photobacterium/enzimologia , Photobacterium/genética , Estados Unidos , United States Environmental Protection Agency
15.
Biochem J ; 316 ( Pt 2): 661-5, 1996 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-8687414

RESUMO

Vitamin B12-dependent methionine synthase is an important enzyme for sulphur amino acid, folate polyamine metabolism, S-adenosylmethionine metabolism and also in the methylation pathway of DNA, RNA, proteins and lipids. Consequently, studies aiming at exploring the control and regulation of methionine synthase are of particular interest. Here we report the modulation of enzyme activity in vitro by polyamines. Although putrescine, cadaverine, spermine and spermidine all stimulated enzyme activity, the last two were the most potent, causing increases in enzyme activity up to 400%. The EC50 for spermine was determined as 8 microM and for spermidine 40 microM. The physiological concentration for spermine has been reported to be 15-19 microM. Spermine was found to increase both the Km and the V(max) with respect to methyltetrahydrofolate for the enzyme. These data support the hypothesis that spermine and spermidine are feedback regulators of methionine synthase both in vivo and in vitro and are consistent with the polyamines' regulating cell signalling pathways.


Assuntos
5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/metabolismo , Fígado/enzimologia , Poliaminas/farmacologia , Vitamina B 12/farmacologia , 5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/isolamento & purificação , Animais , Cadaverina/farmacologia , Ativação Enzimática , Retroalimentação , Cinética , Modelos Químicos , Putrescina/farmacologia , Ratos , Ratos Wistar , Espermina/farmacologia
16.
Eur J Clin Invest ; 26(2): 167-70, 1996 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8904527

RESUMO

The research described here provides one mechanism of uniting current effects of nitric oxide (NO) with the elevated levels of homocysteine detected in patients with cardiovascular and other disease. Time- and dose-dependent studies of the inhibition of purified mammalian methionine synthase by NO were performed. The in vitro study gave an effective IC50 value of 3 mu mol L-1. Methionine synthase converts cellular homocysteine to methionine and is a major enzyme in the biosynthetic pathways for folates, S-adenosylmethionine and biological methylations, sulphur amino acids and polyamines. Nitric oxide-induced inactivation of methionine synthase alters the levels of these metabolites and could therefore provide a connection between the cardiovascular effects of NO, the plasma homocysteine levels and cardiovascular diseases that is complementary to the more traditional NO-induced stimulation of guanylate cyclase and the convertion of homocysteine to oxidized sulphur amino acids.


Assuntos
5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/antagonistas & inibidores , Óxido Nítrico/farmacologia , Animais , Homocisteína/metabolismo , Ratos , Ratos Wistar
17.
J Biol Chem ; 270(37): 21701-6, 1995 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-7665587

RESUMO

Several hundred phosphinic peptides having the general formula Z-(L,D)Phe psi (PO2CH2)(L,D)Xaa'-Yaa'-Zaa', where Xaa' = Gly or Ala and Yaa' and Zaa' represent 20 different amino acids, have been synthesized by the combinatorial chemistry approach. Peptide mixtures or individual peptides were evaluated for their ability to inhibit the rat brain zinc endopeptidases 24-15 and 24-16. Numerous phosphinic peptides of this series act as potent (Ki in the nanomolar range) mixed inhibitors of these two peptidases. However, our systematic and comparative strategy led us to delineate the residues located in P2' and P3' positions of the inhibitors that are preferred by these two peptidases. Thus, endopeptidase 24-15 exhibits a marked preference for inhibitors containing a basic residue (Arg or Lys) in the P2' position, while 24-16 prefers a proline in this position. The P3' position has less influence on the inhibitory potency and selectivity, both peptidases preferring a hydrophobic residue at this position. On the basis of these observations, we have prepared highly potent and selective inhibitors of endopeptidase 24-15. The Z-(L,D)Phe psi-(PO2CH2)(L,D)Ala-Arg-Met compound (mixture of the four diastereoisomers) displays a Ki value of 70 pM for endopeptidase 24-15. The most selective inhibitor of endopeptidase 24-15 in this series, Z-(L,D)Phe psi (PO2-CH2)(L,D)Ala-Arg-Phe, exhibits a Ki value of 0.160 nM and is more than 3 orders of magnitude less potent toward endopeptidase 24-16 (Ki = 530 nM). Furthermore, at 1 microM this selective inhibitor is unable to affect the activity of several other zinc peptidases, namely endopeptidase 24-11, angiotensin-converting enzyme, aminopeptidase M, leucine aminopeptidase, and carboxypeptidases A and B. Therefore, Z-(L,D)Phe psi (PO2CH2)(L,D)Ala-Arg-Phe can be considered as the most potent and specific inhibitor of endopeptidase 24-15 developed to date. This new inhibitor should be useful in assessing the contribution of this proteolytic activity in the physiological inactivation of neuropeptides known to be hydrolyzed, at least in vitro, by endopeptidase 24-15. Our study also demonstrates that the combinatorial chemistry approach leading to the development of phosphinic peptide libraries is a powerful strategy for discovering highly potent and selective inhibitors of zinc metalloproteases and should find a broader application in studies of this important class of enzymes.


Assuntos
Encéfalo/enzimologia , Metaloendopeptidases/metabolismo , Peptídeos/farmacologia , Ácidos Fosfínicos/farmacologia , Inibidores de Proteases/farmacologia , Sequência de Aminoácidos , Animais , Cinética , Metaloendopeptidases/isolamento & purificação , Dados de Sequência Molecular , Peptídeos/síntese química , Inibidores de Proteases/síntese química , Ratos , Relação Estrutura-Atividade
18.
Biochem J ; 307 ( Pt 1): 239-44, 1995 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-7717982

RESUMO

Highly purified rat brain myelin was solubilized in Triton X-100 and myelin phospholipid N-methyltransferase was characterized. The enzyme activities were separated by isoelectric focusing and ion-exchange chromatography. The phospholipid methyl-transferase has shown at least four peaks of activity with pIapp. values of 4.5, 5.2, 6.2 and 8.4. After affinity purification each of these activities revealed a close set of bands of approx. 65 kDa on SDS/PAGE. These data together with those from preparative SDS/PAGE separations suggested that rat brain myelin contains three acidic and at least one basic phospholipid-methylating isoenzymes and that the major isoenzyme in each case is approx. 65 kDa in size. While the predominant product of the reaction catalysed by all detected isoforms was monomethylated phosphatidylethanolamine, the least acidic isoform (pIapp. 6.2) also formed about 20% phosphatidylcholine, suggesting that these isoenzymes may play different roles in vivo.


Assuntos
Química Encefálica , Isoenzimas/metabolismo , Lipídeos de Membrana/metabolismo , Metiltransferases/metabolismo , Bainha de Mielina/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Fosfolipídeos/metabolismo , Animais , Cromatografia de Afinidade , Cromatografia por Troca Iônica , Ponto Isoelétrico , Isoenzimas/química , Isoenzimas/isolamento & purificação , Metilação , Metiltransferases/química , Metiltransferases/isolamento & purificação , Peso Molecular , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/isolamento & purificação , Fosfatidiletanolamina N-Metiltransferase , Fosfatidiletanolaminas/metabolismo , Ratos
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