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Apendicite , Doença Aguda , Adulto , Apendicectomia , Apendicite/diagnóstico , Apendicite/cirurgia , HumanosRESUMO
BACKGROUND: Bariatric surgery is an accepted treatment option for severe obesity. Previous analysis of the independently collected Hospital Episode Statistics (HES) data for outcomes after bariatric surgery demonstrated a 30-day postoperative mortality rate of 0·3 per cent in the English National Health Service (NHS). However, there have been no published mortality data for bariatric procedures performed since 2008. This study aimed to assess mortality related to bariatric surgery in England from 2009. METHODS: HES data were used to identify all patients who had primary bariatric surgery from 2009 to 2016. Clinical codes were used selectively to identify all primary bariatric procedures but exclude revision or conversion procedures and operations for malignant or other benign disease. The primary outcome measures were HES in-hospital and Office for National Statistics (ONS) 30-day mortality after discharge. RESULTS: A total of 41 241 primary bariatric procedures were carried out in the NHS between 2009 and 2016, with 29 in-hospital deaths (0·07 per cent). The 30-day mortality rate after discharge was 0·08 per cent (32 of 41 241). Both the in-hospital and 30-day mortality rates after discharge demonstrated a downward trend over the study period. CONCLUSION: Overall in-hospital and 30-day mortality rates remain very low after primary bariatric surgery. An increased uptake of bariatric surgery within the English NHS has been safe.
RESUMO
BACKGROUND: The culture of cancer cells has many applications in chemosensitivity testing and new drug development. PURPOSE: Our goal was to adapt simple semiautomated microculture methods for testing the chemosensitivity of melanoma cells freshly recovered from patients' tumors. METHODS: Cells were cultured on a substrate of agarose and exposed continuously to cytotoxic drugs, the effects of which were measured by determining the uptake of [3H]thymidine 4-7 days later. RESULTS: Immunocytochemical staining of cells cultured with 5-bromo-2'-deoxyuridine demonstrated that tumor cells were responsible for the measured thymidine incorporation. The effects of cytotoxic drugs were calculated as logarithmic 50% inhibitory concentrations and expressed as divergences from the mean in a log-mean graph. The inhibitory effects of amsacrine, etoposide, doxorubicin, cisplatin, mitomycin C, and fluorouracil were tested. Tumors differed widely in their sensitivity to these drugs, although sensitivity to the three topoisomerase-II-directed agents was highly correlated. Cells from two non-neoplastic hematopoietic progenitor cell lines (FT and 32D) showed chemosensitivity patterns distinct from those in the melanoma cells, indicating tissue selectivity. Two established melanoma cell lines, MM-96 and FME, were tested under the same conditions and showed sensitivity typical of at least some fresh specimens. CONCLUSIONS: These results support the validity of melanoma cell lines as models of freshly resected melanoma cells. If successfully applied to other tumor types, such semiautomated approaches could find wide application in routine hospital laboratories for the chemosensitivity testing of patients' tumor cells.
Assuntos
Antineoplásicos/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Melanoma/tratamento farmacológico , Animais , Linhagem Celular , Estudos de Viabilidade , Células-Tronco Hematopoéticas/efeitos dos fármacos , Humanos , Melanoma/patologia , Camundongos , Células Tumorais Cultivadas/efeitos dos fármacosRESUMO
BACKGROUND: Two types of biaryl crosslinks can be formed with natural protein sidechains: ditryptophan and dityrosine. Biaryl crosslinks have the same topology as disulfide crosslinks, yet little is known about their effect on local peptide structure. RESULTS: Three ditryptophan-linked peptide dimers based on the sequence Ac-Leu-Trp-Ala-COX were prepared. The tripeptide dimer with -CONH(2) termini was too insoluble to study, but the tripeptide dimer with -COOMe termini crystallized from methanol/chloroform as an antiparallel beta-sheet. The tripeptide dimer with a -CONMe(2) termini adopted a slipped antiparallel beta structure in methanol/chloroform. CONCLUSIONS: These results suggest that intermolecular ditryptophan crosslinks that join the middle of peptide chains can confer a preference for antiparallel beta-sheet structure. The effect is most dramatic when both the inside and outside edges of the dimer can form hydrogen bonds as in the crystal structure of dimer 3b.
Assuntos
Oligopeptídeos/química , Triptofano/metabolismo , Cristalização , Cristalografia por Raios X , Dimerização , Ligação de Hidrogênio , Modelos Moleculares , Estrutura Secundária de Proteína , SolubilidadeRESUMO
Background and Aim. The optimum management of Bowen's Disease (BD) is undefined. A review of current practice is required to allow the development of best practice guidelines. Methods. All BD cases, diagnosed in one UK centre and one Australian centre over a year (1 July 2012-30 June 2013), were analysed retrospectively. Patients with BD were identified from histopathology reports and their medical records were analysed to collect demographic data, site of lesion, and treatment used. Results. The treatment of 155 lesions from the UK centre and 151 lesions from the Australian centre was analysed. At both centres BD was most frequently observed on the face: UK had 70 (45%) lesions and Australia had 83 (55%) lesions (P = 0.08). The greatest number of lesions was managed by the plastic surgery department in the UK centre, 72 (46%), and the dermatology department in the Australian centre, 121 (80%). The most common therapy was surgical excision at both centres. Conclusions. In both UK and Australia, BD arises on sun-exposed sites and was most commonly treated with surgical excision despite a lack of robust evidence-based guidelines.
RESUMO
On the basis of the data suggesting that adolescents and young adult patients with acute lymphoblastic leukemia (ALL) have improved outcomes when treated on pediatric protocols, we assessed the feasibility of treating adult patients aged 18-50 years with ALL with the DFCI Pediatric ALL Consortium regimen utilizing a 30-week course of pharmacokinetically dose-adjusted E. coli L-asparaginase during consolidation. Between 2002 and 2008, 92 eligible patients aged 18-50 years were enrolled at 13 participating centers. Seventy-eight patients (85%) achieved a complete remission (CR) after 1 month of intensive induction therapy. With a median follow-up of 4.5 years, the 4-year disease-free survival (DFS) for the patients achieving a CR was 69% (95% confidence interval (CI) 56-78%) and the 4-year overall survival (OS) for all eligible patients was 67% (95% CI 56-76%). The 4-year DFS for the 64 patients who achieved a CR and were Philadelphia chromosome negative (Ph-) was 71% (95% CI 58-81%), and for all 74 Ph- patients the 4-year OS was 70% (95% CI 58-79%). We conclude that a pediatric-like treatment strategy for young adults with de novo ALL is feasible, associated with tolerable toxicity, and results in improved outcomes compared with historical regimens in young adult patients with ALL.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Asparaginase/administração & dosagem , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Adolescente , Adulto , Citarabina/administração & dosagem , Doxorrubicina/administração & dosagem , Esquema de Medicação , Feminino , Humanos , Cariotipagem , Masculino , Metotrexato/administração & dosagem , Pessoa de Meia-Idade , Medicina de Precisão , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidade , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Prednisona/administração & dosagem , Indução de Remissão , Análise de Sobrevida , Resultado do Tratamento , Vincristina/administração & dosagemRESUMO
The deoxyuridine (dU) suppression test evolved out of investigations into the biochemical basis of the megaloblastic changes seen in vitamin B12 and folate deficiency. Although the abnormality in dU suppression which occurs in vitamin B12- or folate-deficient states is assumed to reflect impaired methylation of deoxyuridylate, there is still no direct demonstration that this is so. Furthermore, there is evidence that reactions other than the methylation of deoxyuridylate are involved in the phenomenon of dU suppression. Nevertheless, in clinical practice abnormal dU suppression serves as a sensitive index of the presence of megaloblastosis due to vitamin B12 or folate deficiency. dU suppression is also abnormal in a number of conditions other than vitamin B12 or folate deficiency, but its overall specificity in detecting tissue dysfunction due to these two deficiency states is considerably higher than that of the serum vitamin B12 or red cell folate levels. Consequently, the test enables us simply and rapidly to define those patients in whom macrocytosis is unrelated to a deficiency of vitamin B12 or folate. For these reasons, the dU suppression test has been adopted by several laboratories across the world for investigating patients with (a) possible vitamin B12 or folate deficiency, (b) macrocytosis, and (c) megaloblastic erythropoiesis. Since the dU suppression test is abnormal in transcobalamin II deficiency and in some congenital disorders of vitamin B12 and folate metabolism, it is very useful in the investigation of obscure anaemias in infancy and childhood. In addition, it has contributed to our understanding of the mechanisms underlying the myelotoxicity of certain drugs, and particularly of nitrous oxide.
Assuntos
Desoxiuridina/genética , Doenças Hematológicas/diagnóstico , Supressão Genética , HumanosRESUMO
The influence of bepridil on steady-state serum digoxin concentrations (SDCs) and the pharmacodynamic actions of both drugs were tested in 48 healthy subjects in a randomized, double-blind study. Subjects were assigned to one of two groups of 24 subjects each: One group received placebo 1, while the other received digoxin, 0.375 mg/day, loaded with doubled doses on days 1 and 2, for 14 days. After 7 days the groups were subdivided into four groups of 12 subjects each and received concurrent dosing of digoxin with either placebo 2 or bepridil, 300 mg/day, loaded with 900 mg on day 8. Mean (+/- SD) SDCs rose during concurrent bepridil dosing from 0.93 +/- 0.22 to 1.25 +/- 0.25 ng/ml (P less than 0.001). Noninvasive cardiovascular parameters from ECG, systolic time intervals, and electrical impedance cardiography were not influenced by the placebos. Digoxin and bepridil reduced heart rate and prolonged the PQ interval because of negative chronotropic and dromotropic properties. Positive inotropism from digoxin shortened the corrected electromechanical systole (QS2c) and the preejection period and increased impedance cardiography [(dZ/dt)/RZ index]; the opposite effects occurred after bepridil, indicating negative inotropism. The QT interval corrected for heart rate (QTc) showed a similar pattern of changes, as did QS2c for each drug. Concurrent dosing of both drugs resulted in an addition of their chronotropic effects, whereas the dromotropic effects of each drug alone was not intensified. The strengthened digoxin effect from the increased SDC diminished the negative inotropic effect of bepridil. Overall, drug coadministration resulted in a nearly unchanged digoxin-induced positive inotropism.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Digoxina/sangue , Hemodinâmica/efeitos dos fármacos , Pirrolidinas/farmacologia , Adulto , Bepridil , Digoxina/metabolismo , Método Duplo-Cego , Interações Medicamentosas , Eletrocardiografia , Feminino , Humanos , Cinética , Masculino , Distribuição AleatóriaRESUMO
Hemodynamic responses after urapidil were compared with those after dihydralazine in placebo-controlled, double-blind studies after cumulative intravenous doses. We recorded heart rate, blood pressure, systolic time intervals corrected for heart rate (electromechanical systole and preejection period), electrical impedance cardiography [(dZ/dt)/RZ index and mean electrical thorax impedance], and M-mode echocardiogram (end-systolic and -diastolic diameters, end-systolic wall stress, fractional shortening, and cardiac output). Both drugs induced dose-dependent reductions in total peripheral resistance, which resulted in reduction in left ventricular end-systolic wall stress and increases in heart rate (limited at +10 bpm with urapidil), fractional shortening, cardiac output, and the (dZ/dt)/RZ index. With each drug, diastolic blood pressure fell by 5 mm Hg, the corrected preejection period shortened (dihydralazine greater than urapidil), the corrected electromechanical systole did not change, and mean electrical thorax impedance rose with urapidil. The spectrum of effects indicates that both drugs reduce left ventricular afterload, thereby increasing left ventricular pump performance. Urapidil also exerts some preload reduction.
Assuntos
Di-Hidralazina/farmacologia , Hemodinâmica/efeitos dos fármacos , Hidralazina/análogos & derivados , Piperazinas/farmacologia , Adulto , Pressão Sanguínea/efeitos dos fármacos , Cardiografia de Impedância , Ensaios Clínicos como Assunto , Di-Hidralazina/administração & dosagem , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino , Piperazinas/administração & dosagem , Distribuição Aleatória , Sístole/efeitos dos fármacos , Resistência Vascular/efeitos dos fármacosRESUMO
Seven new low-passage melanoma lines were developed in this laboratory from clinical melanoma specimens and characterised for chromosome complement, DNA ploidy and S-phase content. The radiosensitivity of these lines was compared with that of eight established melanoma cell lines, FME, MM-96, SK-MEL-5, SK-MEL-28, SK-MEL-2, MALME-3M, M19-MEL and LOX-IMVI, using a 96-well microculture assay technique. Dose-response curves were determined using a 5-day incubation period and 6-h terminal [3H]thymidine-labelling period. Radiation (60Co source) was carried out under a lead wedge to provide a radiation dose range of 0-10 Gy, or by irradiating part of the plate (radiation dose 0 or 2 Gy). Data for a range of cell densities in a single 96-well plate were combined into a single regression equation incorporating linear quadratic terms for radiation dose and cell density. SF2 values were defined as the amount of thymidine incorporated following a radiation dose of 2 Gy, expressed as a fraction of that of unirradiated cells, and varied from 0.36 to 0.93. The reproducibility in repeat assays, as defined by the standard error of determinations at different passage numbers, was +/- 0.04. The newly developed lines exhibited a similar range of radiosensitivity to that of the established lines, and melanin content did not correlate with resistance. For nine of the lines, radiation parameters were also determined using a modified Courtenay clonogenic soft agar assay technique, and the results compared with the thymidine incorporation results, and a significant linear correlation was found between SF2 and SF2' (r = 0.89). The linear (alpha) and quadratic (beta) terms of the best-fit linear quadratic dose-response curves, were significantly correlated between the two assays. It is concluded for this series of human melanoma lines that proliferation assays in 96-well plates provide radiosensitivity parameters comparable to those using clonogenic assays.
Assuntos
Melanoma/radioterapia , Tolerância a Radiação , Adulto , Idoso , Sobrevivência Celular/efeitos da radiação , Relação Dose-Resposta à Radiação , Feminino , Humanos , Masculino , Melanoma/metabolismo , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Timidina/metabolismo , Células Tumorais Cultivadas/metabolismo , Células Tumorais Cultivadas/efeitos da radiação , Ensaio Tumoral de Célula-TroncoRESUMO
Paclitaxel, a drug which stabilises microtubules, demonstrates marked activity against ovarian cancer. We investigated the sensitivity to paclitaxel of tumour cells from disaggregated solid tumours or tumour-bearing ascites from 7 ovarian cancer patients, and 21 established tumour cell lines (ovarian, melanoma and lung). Response was quantitated by [3H]-thymidine incorporation in 96-well plates or by colony growth. Dose-response curves to paclitaxel were biphasic with a dose-dependent phase providing an IC50 value (50% reduction in incorporation) and dose-dependent "plateau" phase where the effect was independent of paclitaxel concentration. IC50 values ranged from 2.5 to 110 nM with evidence of multidrug resistance in the two most resistant cell lines. The "plateau" killing values varied from 0.1 log10 to > 3.4 log10 units reduction, and were found to be significantly correlated (r = 0.86; P < 0.0001) with logarithmic culture doubling times of the cell lines. Cellular glutathione levels were measured and found not to be significantly associated with response to paclitaxel. The results suggest that the ratio of paclitaxel exposure time to the culture doubling time is a major factor in paclitaxel cytotoxicity. The relationship between tumour cell cytokinetics and paclitaxel pharmacokinetics in vivo may therefore be crucial in determining clinical paclitaxel response.
Assuntos
Neoplasias Ovarianas/tratamento farmacológico , Paclitaxel/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Sobrevivência Celular , Relação Dose-Resposta a Droga , Resistência a Medicamentos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Glutationa/metabolismo , Humanos , Pessoa de Meia-Idade , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismo , Ensaio Tumoral de Célula-TroncoRESUMO
PURPOSE: This study investigated the short- and medium-term effects of pelvic radiotherapy and surgery on the sexual function of women treated for cervical cancer. METHODS AND MATERIALS: Sixteen women with Stages I, II, or III disease referred for radiotherapy treatment were assessed. Six had undergone prior hysterectomy. The women were assessed with questionnaires prior to radiotherapy, at completion of radiotherapy, and at 6 weeks and 14 weeks after radiotherapy treatment. The clinical findings at routine follow-up were noted. RESULTS: The study showed significant changes in sexual activity and satisfaction as a result of treatment. This was due to a number of physical and psychological factors. The level of sexual activity was lowest at completion of radiotherapy treatment. A feeling of vaginal shortening was the most frequent reason and was more common in women who were treated with surgery and radiotherapy. Dyspareunia, bleeding, and concern of bleeding and/or recurrence were all significant factors. CONCLUSIONS: The questionnaires were an effective way of assessing women's sexual function. Radiotherapy caused sexual dysfunction in one-half of women. Combined treatment with radiotherapy and surgery results in a higher risk than radiotherapy alone. Women with cervical cancer and undergoing radiotherapy treatment require considerable counseling and support.
Assuntos
Radioterapia/efeitos adversos , Comportamento Sexual , Neoplasias do Colo do Útero/radioterapia , Neoplasias do Colo do Útero/cirurgia , Coito , Terapia Combinada , Feminino , Seguimentos , Humanos , Histerectomia , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Satisfação do Paciente , Radioterapia/métodos , Dosagem Radioterapêutica , Inquéritos e Questionários , Fatores de Tempo , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/psicologiaRESUMO
The surviving fraction of human tumor cell lines after 2 Gy (SF2) varies between 0.1 and 0.8. It has been postulated that differences in inherent radiosensitivity of tumor cells are a major determinant of radiation response in vivo. Assays of inherent radiosensitivity based on acute survival are being developed as predictors of tumor response which often assume that the same inherent radiosensitivity persists throughout a fractionated treatment. We have investigated the response of 2 human tumor cell lines (A549 and MCF7) with different inherent radiosensitivities to in vitro fractionated irradiation. A549 cells had an SF2 of 0.62 and a mean inactivation dose (D) of 3.07 Gy whereas MCF7 cells had an SF2 of 0.30 and a D of 1.52 Gy. Split dose repair capacity (at equal survival levels) was less for A549 than for MCF7 cells and recovery kinetics for both cell lines were substantially longer than those of rodent cell lines. Survival after 5 fractions of 2 Gy given 12 hr apart at 37 degrees C was near to that predicted from the acute survival curve, assuming complete repair and no proliferation. Acute survival of A549 cells which survived 5 fractions of 2 Gy given 12 hr apart was similar to the acute survival of unirradiated cells. When A549 cells were incubated at 22 degrees C between 5 fractions of 2 Gy given 12 hr apart, proliferation and split dose repair were substantially inhibited. These studies support the proposals to use in vitro inherent radiosensitivity assays for the prediction of in vivo response of tumors to fractionated treatment.
Assuntos
Células Tumorais Cultivadas/efeitos da radiação , Neoplasias da Mama , Linhagem Celular , Sobrevivência Celular/efeitos da radiação , Humanos , Neoplasias Pulmonares , Doses de Radiação , Tolerância a RadiaçãoRESUMO
The X-ray crystal structures of four beta-strand-templated active site inhibitors of thrombin containing P1' groups have been determined and refined at about 2.1-A resolution to crystallographic R-values between 0.148 and 0.164. Two of the inhibitors have an alpha-ketoamide functionality at the scissile bond; the other two have a nonhydrolyzable electrophilic group at the P1' position. The binding of lysine is compared with that of arginine at the S1 specificity site, while that of D,L-phenylalanine enantiomorphs is compared in the S3 region of thrombin. Four different P1' moieties bind at the S1' subsite in three different ways. The binding constants vary between 2.0 microM and 70 pM. The bound structures are used to intercorrelate the various binding constants and also lead to insightful inferences concerning binding at the S1' site of thrombin.
Assuntos
Compostos Aza/química , Compostos Bicíclicos Heterocíclicos com Pontes/química , Peptídeos/química , Inibidores de Serina Proteinase/química , Trombina/antagonistas & inibidores , Sítios de Ligação , Cristalografia por Raios X , Modelos Moleculares , Mimetismo Molecular , Estrutura Secundária de Proteína , Trombina/químicaRESUMO
To determine the functional importance of the low B12 and red cell folate concentrations repeatedly observed in the elderly 200 consecutive patients admitted to a geriatric unit were studied. Forty six of the patients had low serum concentrations of B12 (15), red cell folate (26), or both (five). Serum B12 and red cell folate concentrations correlated with mean cell volume, and serum B12 correlated with the neutrophil lobe count. Bone marrow deoxyuridine suppression was abnormal in 35% of the patients with low vitamin concentrations, but 55% of those with abnormal deoxyuridine suppression had morphologically normal bone marrow, and 73% had a normal mean cell volume. In patients with low vitamin values the deoxyuridine suppressed value correlated with the haemoglobin concentration and neutrophil lobe count. Thus synthesis of thymidylate was impaired by vitamin B12 or folate deficiency in at least 8% of newly admitted elderly patients, many of whom had normal blood counts despite the biochemical disturbance affecting haemopoiesis. A nutritionally depleted diet may have been responsible for many of the low vitamin values.
Assuntos
Eritrócitos/metabolismo , Ácido Fólico/sangue , Vitamina B 12/sangue , Idoso , Medula Óssea/metabolismo , Desoxiuridina , Deficiência de Ácido Fólico/epidemiologia , Hemoglobinas/análise , Humanos , Contagem de Leucócitos , Neutrófilos , Albumina Sérica/metabolismo , Tiroxina/sangue , Deficiência de Vitamina B 12/epidemiologiaRESUMO
Uteroglobin, a steroid-inducible, cytokine-like, secreted protein with immunomodulatory properties, has been reported to bind progesterone, polychlorinated biphenyls (PCB), and retinol. Structural studies may delineate whether binding of ligands is a likely physiological function of human uteroglobin (hUG). We report a refined crystal structure of uncomplexed recombinant hUG (rhUG) at 2.5-A resolution and the results of our molecular modeling studies of ligand binding to the central hydrophobic cavity of rhUG. The crystal structure of rhUG is very similar to that of reported crystal structures of uteroglobins. Using molecular modeling techniques, the three ligands--PCB, progesterone, and retinol--were docked into the hydrophobic cavity of the dimer structure of rhUG. We undocked the progesterone ligand by pulling the ligand from the cavity into the solvent. From our modeling and undocking studies of progesterone, it is clear that these types of hydrophobic ligands could slip into the cavity between helix-3 and helix-3' of the dimer instead of between helix-1 and helix-4 of the monomer, as proposed earlier. Our results suggest that at least one of the physiological functions of UG is to bind to hydrophobic ligands, such as progesterone and retinol.
Assuntos
Modelos Moleculares , Ligação Proteica/fisiologia , Estrutura Terciária de Proteína/fisiologia , Proteínas Recombinantes/química , Uteroglobina/química , Animais , Cristalografia por Raios X/métodos , Humanos , LigantesRESUMO
The successful treatment of cancer requires the identification of new drugs with novel actions. N-[2-(Dimethylamino)ethyl]acridine-4-carboxamide dihydrochloride (DACA) is a topoisomerase II-targeted antitumour drug with curative activity against murine Lewis lung carcinoma. DACA was assessed for novel patterns of growth inhibition using normal and multidrug-resistant human cell lines. Cells were cultured in 96-well microtitre trays and tested against DACA and related topoisomerase-directed drugs, including amsacrine, etoposide and doxorubicin, and drug concentrations for 50% growth inhibition (IC50 or GI50 values) were determined. In a series of Jurkat leukaemia lines characterised as exhibiting atypical multidrug resistance, DACA was to a large extent capable of overcoming multidrug resistance exhibited towards the other topoisomerase-directed agents. DACA was also tested against the National Cancer Institute 60-tumour-specific cell-line panel (GI50 values ranging from 420 to 5,400 nM; mean, 2,100 nM) and against a series of primary cultures of surgically excised melanomas (IC50 values ranging from 60 to 1,600 nM; mean, 590 nM). DELTA values (deviations of logarithmic IC50 or GI50 values from the mean) were calculated and compared by correlation analysis. The standard deviation of DELTA values was found to be lower for DACA than for the other topoisomerase II-directed drugs amsacrine, etoposide, doxorubicin and mitozantrone in both the cell lines and the primary cultures. These lower standard deviations appear to have resulted from the reduced susceptibility of DACA to both P-glycoprotein- and topoisomerase II-mediated multidrug-resistance mechanisms occurring naturally in cell lines and primary cultures.
Assuntos
Acridinas , Aminoacridinas/farmacologia , Antineoplásicos/farmacologia , Leucemia/tratamento farmacológico , Melanoma/tratamento farmacológico , DNA Topoisomerases Tipo I/efeitos dos fármacos , Resistência a Medicamentos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Substâncias Intercalantes/farmacologia , Células Tumorais Cultivadas/efeitos dos fármacosRESUMO
The vitamin B12 antagonist cyanocobalamin [c-lactam] was cytotoxic to cultured human leukemia cells, grown in methylfolate, homocysteine, and vitamin B12, but not in the presence of methionine. Small concentrations of methionine were effective in restoring the growth rate in a dose-dependent fashion, confirming methionine deficiency as the cytotoxic principle. Cyanocobalamin [c-lactam] prevented utilization of the methyl group of methylfolate, but no evidence of folate deficiency developed in long-term culture. High concentrations of non-methylated folate were unable to reverse the cytotoxicity, excluding a methylfolate 'trap' as the cause. Low concentrations of serine in the medium induced transient biochemical megaloblastosis. Cyanocobalamin [c-lactam] caused this to occur earlier, and persist. In high concentrations of serine, the inhibitor caused only transient changes in deoxyuridine suppression. Homocysteine cannot be remethylated without vitamin B12, and condensation with serine is the only other excretory pathway for this toxic amino acid. We hypothesize that impaired DNA synthesis in vitamin B12 deficiency is the result of diverting serine away from thymidylate synthesis, into homocysteine metabolism.
Assuntos
Leucemia/tratamento farmacológico , Vitamina B 12/antagonistas & inibidores , 5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/antagonistas & inibidores , Sobrevivência Celular/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Células HL-60 , Humanos , Células K562 , Modelos Lineares , Modelos Logísticos , Metilmalonil-CoA Mutase/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
A 23-year-old black female presented with general malaise, headache, high white cell count (136 x 10(9)/L), thrombocytopenia and nephrotic syndrome. She proved to have large granular lymphoproliferative disease with a natural killer cell phenotype and without a clonal rearrangement of the T-cell receptor genes. Renal biopsy demonstrated focal segmental glomerulosclerosis (FSGS). She developed a monophasic neurological illness, and rapidly became comatose six days after the initiation of high dose prednisone therapy. Computerized tomography of the brain showed marked hypodensity of the subcortical white matter. She regained consciousness subsequently, but died six months after her initial presentation with uncontrolled lymphocytosis and renal failure. Autopsy revealed FSGS with glomerular collapse and microcystic dilatation of the renal tubules, and there was perivascular demyelination in the subcortical white matter of the brain. We speculate that lymphokines released by the natural killer cells may have played an important role in the pathogenesis of both the nephrotic syndrome and leukoencephalopathy.
Assuntos
Encefalomielite/etiologia , Transtornos Linfoproliferativos/complicações , Síndrome Nefrótica/etiologia , Insuficiência Renal/etiologia , Doença Aguda , Adulto , Feminino , Humanos , Linfocinas/fisiologiaRESUMO
Metastatic melanoma is notable for its resistance to chemotherapy, and methods for determining resistance in cultures would be advantageous. We investigated the chemosensitivities of seven newly derived low passage lines and eight established melanoma lines. A 96-well microculture system utilising [3H]-thymidine incorporation was used to determine IC50 values (50% inhibitory concentrations) for lomustine, mitomycin C, 4-hydroperoxycyclophosphamide, cisplatinum, 5-fluorouracil, vincristine, doxorubicin, etoposide, amsacrine and the amsacrine analogue CI-921. Cytokinetic parameters were determined using 5-bromodeoxyuridine and flow cytometry. The presence of "transport" and "atypical" multidrug resistance was investigated with an IC50 ratio method, using pairs of drugs with differing sensitivity to these multidrug resistance mechanisms. A wide range of chemosensitivity for each of the antitumor agents was observed, and a spectrum of activity was observed in each of the assays for multidrug resistance. Unexpectedly, a number of cell lines displayed coordinate sensitivity or resistance to cytotoxic agents with unrelated mechanisms of action. Resistance mechanisms apart from "transport" and "atypical" multidrug resistance may be required to account for the observed 40-fold range in overall chemosensitivity of the melanoma lines.