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Molecular-based analysis has become a fundamental tool to understand the role of Quaternary glacial episodes. In the Magellan Province in southern South America, ice covering during the last glacial maximum (20 ka) radically altered the landscape/seascape, speciation rates and distribution of species. For the notothenioid fishes of the genus Harpagifer, in the area are described two nominal species. Nevertheless, this genus recently colonized South America from Antarctica, providing a short time for speciation processes. Combining DNA sequences and genotyping-by-sequencing SNPs, we evaluated the role of Quaternary glaciations over the patterns of genetic structure in Harpagifer across its distribution in the Magellan Province. DNA sequences showed low phylogeographic structure, with shared and dominant haplotypes between nominal species, suggesting a single evolutionary unit. SNPs identified contrastingly two groups in Patagonia and a third well-differentiated group in the Falkland/Malvinas Islands with limited and asymmetric gene flow. Linking the information of different markers allowed us to infer the relevance of postglacial colonization mediated by the general oceanographic circulation patterns. Contrasting rough- and fine-scale genetic patterns highlights the relevance of combined methodologies for species delimitation, which, depending on the question to be addressed, allows discrimination among phylogeographic structure, discarding incipient speciation, and contemporary spatial differentiation processes.
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DNA Mitocondrial , Variação Genética , Animais , DNA Mitocondrial/genética , Peixes/genética , Haplótipos , Filogenia , FilogeografiaRESUMO
Members of the trochoidean genus Margarella (Calliostomatidae) are broadly distributed across Antarctic and sub-Antarctic ecosystems. Here we used novel mitochondrial and nuclear gene sequences to clarify species boundaries and phylogenetic relationships among seven nominal species distributed on either side of the Antarctic Polar Front (APF). Molecular reconstructions and species-delimitation analyses recognized only four species: M. antarctica (the Antarctic Peninsula), M. achilles (endemic to South Georgia), M. steineni (South Georgia and Crozet Island) and the morphologically variable M. violacea (=M. expansa, M. porcellana and M. pruinosa), with populations in southern South America, the Falkland/Malvinas, Crozet and Kerguelen Islands. Margarella violacea and M. achilles are sister species, closely related to M. steineni, with M. antarctica sister to all these. This taxonomy reflects contrasting biogeographic patterns on either side of the APF in the Southern Ocean. Populations of Margarella north of the APF (M. violacea) showed significant genetic variation but with many shared haplotypes between geographically distant populations. By contrast, populations south of the APF (M. antarctica, M. steineni and M. achilles) exhibited fewer haplotypes and comprised three distinct species, each occurring across a separate geographical range. We hypothesize that the biogeographical differences may be the consequence of the presence north of the APF of buoyant kelps - potential long-distance dispersal vectors for these vetigastropods with benthic-protected development - and their near-absence to the south. Finally, we suggest that the low levels of genetic diversity within higher-latitude Margarella reflect the impact of Quaternary glacial cycles that exterminated local populations during their maxima.
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Gastrópodes/classificação , Gastrópodes/genética , Filogeografia , Animais , Regiões Antárticas , Teorema de Bayes , DNA/genética , DNA Mitocondrial/genética , Filogenia , Polimorfismo Genético , América do Sul , Especificidade da Espécie , Fatores de TempoRESUMO
The southern coastline of South America is a remarkable area to evaluate how Quaternary glacial processes impacted the demography of the near-shore marine biota. Here we present new phylogeographic analyses in the pulmonate Siphonaria lessonii across its distribution, from northern Chile in the Pacific to Uruguay in the Atlantic. Contrary to our expectations, populations from the southwestern Atlantic, an area that was less impacted by ice during glacial maxima, showed low genetic diversity and evidence of recent expansion, similar to the patterns recorded in this study across heavily ice-impacted areas in the Pacific Magellan margin. We propose that Atlantic and Pacific shallow marine hard-substrate benthic species were both affected during the Quaternary in South America, but by different processes. At higher latitudes of the southeast Pacific, ice-scouring drastically affected S. lessonii populations compared to non-glaciated areas along the Chile-Peru province where the species was resilient. In the southwest Atlantic, S. lessonii populations would have been dramatically impacted by the reduction of near-shore rocky habitat availability as a consequence of glacio-eustatic movements. The increase of gravelly and rocky shore substrates in the southwest Atlantic supports a hypothesis of glacial refugia from where the species recolonized lower latitudes across the Atlantic and Pacific margins. Our results suggest that current patterns of genetic diversity and structure in near-shore marine benthic species do not solely depend on the impact of Quaternary glacial ice expansions but also on the availability of suitable habitats and life-history traits, including developmental mode, bathymetry and the likelihood of dispersal by rafting.
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Ecossistema , Gastrópodes/genética , Variação Genética , Camada de Gelo , Elevação do Nível do Mar , Animais , Oceano Atlântico , Chile , Genética Populacional , Peru , Filogenia , Filogeografia , UruguaiRESUMO
PURPOSE: Multiple fixation techniques exist for treating progressive neuromuscular scoliosis including pedicle screws, sublaminar bands/wires, hooks or a combination of instruments. Most sublaminar band constructs are supplemented with pedicle screws, hooks and/or sublaminar wires particularly at the top of the construct. There are no studies to date that describe an all/predominant sublaminar band construct. The purpose of this study was to investigate the outcomes of a sublaminar polyester band construct to treat neuromuscular scoliosis. METHODS: A retrospective review was conducted of 32 cases of neuromuscular scoliosis treated with posterior spinal fusion using a sublaminar band construct between 2013 and 2016 by a single surgeon at a single centre. Preoperative, immediate postoperative and two-year follow-up radiographs and clinical records were reviewed. Sagittal, coronal and pelvic obliquity correction was measured. Blood loss, length of surgery and complications were recorded. RESULTS: In all, 29 patients were included. Mean postoperative coronal plane correction was 57% (0% to 92%) and maintained at two-year follow-up. Mean sagittal balance was 2.3 cm (-2.5 to 6.4). Mean lumbar lordosis angle decreased by 7° (44° to 37°). Mean thoracic kyphosis angle increased by 9° (23° to 32°). Mean pelvic obliquity decreased by 50% (from 15° to 7°). There were four major complications (14%) and eight minor complications (21%). Mean blood loss was 1304 cc (250 cc to 2450 cc). CONCLUSION: Sublaminar polyester band fixation constructs provide a viable option in correction of deformity in patients with neuromuscular scoliosis with comparable outcomes with what is reported with other constructs. LEVEL OF EVIDENCE: V.
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PURPOSE: Spica magnectic resonance imaging (MRI) is an established technique for postoperative determination of hip reduction in patients treated for developmental dysplasia of the hip (DDH). A hip abduction angle >55° is considered excessive and has been associated with epiphyseal osteonecrosis. Our purpose was to establish objective criteria for measuring hip abduction angles on MRI after hip reduction and spica casting in patients with DDH, and evaluate reproducibility and reliability of angle measurement using these criteria. METHODS: Forty patients with DDH at our institution who underwent spica MRI after hip reduction between 3 April 2008 and 3 March 2015 were identified. Hip abduction angles were measured on proton density axial images as follows. A transverse line was drawn connecting the posterior ischial tuberosities. A second line was drawn medially along the distal femoral diaphysis, and the angle between these two lines was measured; this value was subtracted from 90°, yielding the degree of abduction from midline. Measurements were independently performed by three faculty radiologists, one orthopedist, and one radiology resident. Inter-reader and intra-reader reliability was assessed using intraclass correlation (ICC), with 0 representing no agreement and 1 representing perfect agreement. RESULTS: For inter-reader reliability, the ICC of the five physicians was 0.89 (95 % CI 0.84-0.92). For intra-reader reliability, the ICC of the five physicians ranged from 0.90-0.97 (95 % CI 0.85-0.98). The mean standard deviation of hip abduction angle measurement among readers was 3.6°. CONCLUSION: The proposed hip abduction angle measurement criteria for spica MRI are both reproducible and easy to perform. The high ICC and low standard deviation of independently evaluated hip abduction angles indicates high reproducibility of measurement. This applies to both inter- and intra-reader reliability.
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INTRODUCTION: Atrial fibrillation (Afib) is considered to be the most frequent form of cardiac dysrhythmia and is well known as a key risk factor for arterial thromboembolism. The incidence of Afib will increase in the future due to demographic changes as well as improved treatment options for acute and chronic heart diseases. OBJECTIVE: The primary objectives of this analysis were to describe patient characteristics, to assess the resource consumption associated with Afib and to measure costs of direct treatment as well as consequential costs. A secondary objective was to identify factors that influence the costs or the type of Afib. METHODS: The analysis is based on the representative ATRIUM register (Ambulantes Register zur Morbidität des Vorhofflimmerns, Ambulatory register on morbidity of atrial fibrillation), a prospective, multicenter cohort study in which general practitioners and family doctors documented the characteristics and resource utilization of consecutively enrolled patients. The documented resource consumption use was subsequently valued with unit costs. The presented results are focused on the baseline documentation and refer to the period 12 months before enrollment. RESULTS: A total of 3,667 patients (mean age 72.1±9.2 years, 58% men) fulfilled all inclusion criteria and were included by a total of 730 doctors. The patients had an average of 2.4±1.0 risk factors and the most common was hypertension (84% of patients). The most commonly observed comorbidities were heart failure (43%) and coronary heart disease (CHD, 35%). Medicines for oral anticoagulation (86%) and beta blockers (75%) were the most frequently prescribed drugs. A total of 1/3 of all patients received a specific kind of Afib therapy (e. g. drug conversion, cardioversion) during the past 12 months. The disease-specific mean costs of the patients were 3,274±5,134 Euro, while the acute (inpatient) treatment represented the largest proportion of these total costs (1,639±3,623 Euro). Patients with high treatment costs were significantly younger and suffered from more concomitant diseases. CONCLUSION: Atrial fibrillation is associated with significant patient-related attributable costs that are caused particularly by expenditures of inpatient stay. New, innovative treatment strategies seem to offer particular potential savings if they are able to reduce the number of hospitalizations due to Afib itself or subsequent cardiac events.
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Fibrilação Atrial/economia , Fibrilação Atrial/epidemiologia , Custos de Cuidados de Saúde/estatística & dados numéricos , Alocação de Recursos/economia , Revisão da Utilização de Recursos de Saúde , Adulto , Idoso , Idoso de 80 Anos ou mais , Fibrilação Atrial/terapia , Feminino , Alemanha/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Alocação de Recursos/estatística & dados numéricos , Fatores de Risco , Adulto JovemRESUMO
BACKGROUND: Processes of restenosis, following arterial injury, are complex involving different cell types producing various cytokines and enzymes. Among those enzymes, smooth muscle cell-derived matrix metalloproteinases (MMPs) are thought to take part in cell migration, degrading of extracellular matrix, and neointima formation. MMP-9, also known as gelatinase B, is expressed immediately after vascular injury and its expression and activity can be inhibited by statins. Using an established in vivo model of vascular injury, we investigated the effect of the HMG-CoA reductase inhibitor rosuvastatin on MMP-9 expression and neointima formation. MATERIALS AND METHODS: 14-week old male Sprague Dawley rats underwent balloon injury of the common carotid artery. Half of the animals received rosuvastatin (20 mg/kg body weight/day) via oral gavage, beginning 3 days prior to injury. Gelatinase activity and neointima formation were analyzed 3 days and 14 days after balloon injury, respectively. 14 days after vascular injury, proliferative activity was assessed by staining for Ki67. RESULTS: After 14 days, animals in the rosuvastatin group showed a decrease in total neointima formation (0.194±0.01 mm2 versus 0.124±0.02 mm2, p<0.05) as well as a reduced intima/media ratio (1.26±0.1 versus 0.75±0.09, p<0.05). Balloon injury resulted in increased activity of MMP-9 3 days after intervention for both rosuvastatin treated animals and controls with no significant difference observed between the groups. There was a trend towards a reduction in the number of Ki67-positive cells 14 days after injury. CONCLUSIONS: Rosuvastatin attenuates neointima formation without affecting early MMP-9 activity in a rat model of vascular injury.
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Artérias Carótidas/patologia , Cateterismo/efeitos adversos , Fluorbenzenos/uso terapêutico , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Neointima/prevenção & controle , Pirimidinas/uso terapêutico , Sulfonamidas/uso terapêutico , Animais , Modelos Animais de Doenças , Masculino , Metaloproteinase 9 da Matriz/análise , Ratos , Ratos Sprague-Dawley , Rosuvastatina CálcicaAssuntos
Doença de Alzheimer/tratamento farmacológico , Assistência Ambulatorial , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Nootrópicos/uso terapêutico , Idoso , Doença de Alzheimer/epidemiologia , Uso de Medicamentos/estatística & dados numéricos , Alemanha , Assistência Domiciliar/estatística & dados numéricos , HumanosRESUMO
Central nervous system (CNS) drainage may occur via connections to the vasculature, but in animal models up to 50% occurs via perivascular, perineural and primitive lymphatic drainage to cervical lymph nodes. We evaluated efflux of particles from the brain to cervical lymph nodes in normal rats, using Combidex iron oxide-based magnetic resonance imaging (MRI) agent. After intracerebral, intraventricular, intracarotid or intravenous injection of Combidex in normal Long Evans rats, particle localization was assessed by MRI and histochemistry for iron and the dextran coat (n = 27). Intraventricular or intracerebral injection, but not intracarotid administration of Combidex (100 micro g), resulted in MRI signal changes in the deep cervical lymph nodes around the carotid artery, and, less strongly, in the superficial cervical nodes. Within 2 h of Combidex administration, iron was histologically localized in cervical lymph nodes, with patched staining of capsule and peripheral sinus consistent with delivery via multiple afferent lymphatic vessels. Lymph node staining in groups receiving CNS Combidex was significantly different from controls (P < 0.0001) and was significantly localized in the deep vs. superficial cervical lymph nodes (P = 0.0003). The trafficking of the superparamagnetic iron particles from the CNS in the rat could be visualized by MRI and histology. Combidex provides a powerful tool to rapidly assess drainage of virus-sized particles from the CNS.
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Encéfalo/metabolismo , Circulação Cerebrovascular/fisiologia , Ferro/metabolismo , Linfonodos/metabolismo , Óxidos/metabolismo , Animais , Dextranos , Feminino , Óxido Ferroso-Férrico , Imuno-Histoquímica , Injeções Intra-Arteriais , Injeções Intravenosas , Injeções Intraventriculares , Ferro/administração & dosagem , Imageamento por Ressonância Magnética , Nanopartículas de Magnetita , Óxidos/administração & dosagem , Ratos , Ratos Long-Evans , Distribuição Tecidual/fisiologiaRESUMO
In two exploratory studies on the outpatient treatment of patients suffering from Alzheimer dementia research was done into the characteristics of therapy in medical practice on the basis of exemplary interviews of 100 doctors in 2000 and 2002. The interviewers discern the burden of the disease for the patients and their relatives. However, medical treatment is still too scarce and inappropriate as the prescribing of antidementia drugs shows, among which especially acetylcholinesterase inhibitors as drugs of first choice. The spectrum of non-pharmacological interventions is applied but psychosocial measures are under-represented. To maintain the Alzheimer patient's functional level and to thus relieve the caring relatives a multimodal therapy should be intensified preferably by comprehensive co-operations.
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Doença de Alzheimer/tratamento farmacológico , Assistência Ambulatorial , Inibidores da Colinesterase/administração & dosagem , Nootrópicos/administração & dosagem , Doença de Alzheimer/psicologia , Assistência Ambulatorial/psicologia , Cuidadores/psicologia , Inibidores da Colinesterase/efeitos adversos , Ensaios Clínicos como Assunto , Terapia Combinada , Efeitos Psicossociais da Doença , Medicina de Família e Comunidade , Alemanha , Humanos , Nootrópicos/efeitos adversosRESUMO
The incidence of chromosome aberrations in bone marrow cells of 12-month-old SAMP-1 female mice characterized by accelerated aging was 1.8 times higher than in wild-type SAMR-1 females and 2.2 times higher than in SHR females of the same age. Treatment with Epithalon (Ala-Glu-Asp-Gly) starting from the age of 2 months decreased the incidence of chromosome aberrations in SAMP-1, SAMR-1, and SHR mice by 20%, 30.1%, and 17.9%, respectively, compared to age-matched controls (p<0.05). Treatment with melatonin (given with drinking water in a dose of 20 mg/liter in night hours) had no effect on the incidence of chromosome aberrations in SHR mice. These data indicate antimutagenic effect of Epithalon, which probably underlies the geroprotective effect of this peptide.
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Envelhecimento/patologia , Aberrações Cromossômicas , Oligopeptídeos/farmacologia , Animais , Células da Medula Óssea/efeitos dos fármacos , Feminino , Melatonina/farmacologia , CamundongosRESUMO
Researchers at the National Cancer Institute developed a new cognitively based food frequency questionnaire (FFQ), the Diet History Questionnaire (DHQ). The Eating at America's Table Study sought to validate and compare the DHQ with the Block and Willett FFQs. Of 1,640 men and women recruited to participate from a nationally representative sample in 1997, 1,301 completed four telephone 24-hour recalls, one in each season. Participants were randomized to receive either a DHQ and Block FFQ or a DHQ and Willett FFQ. With a standard measurement error model, correlations for energy between estimated truth and the DHQ, Block FFQ, and Willett FFQ, respectively, were 0.48, 0.45, and 0.18 for women and 0.49, 0.45, and 0.21 for men. For 26 nutrients, correlations and attenuation coefficients were somewhat higher for the DHQ versus the Block FFQ, and both were better than the Willett FFQ in models unadjusted for energy. Energy adjustment increased correlations and attenuation coefficients for the Willett FFQ dramatically and for the DHQ and Block FFQ instruments modestly. The DHQ performed best overall. These data show that the DHQ and the Block FFQ are better at estimating absolute intakes than is the Willett FFQ but that, after energy adjustment, all three are more comparable for purposes of assessing diet-disease risk.
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Avaliação Nutricional , Inquéritos e Questionários/normas , Adulto , Idoso , Estudos Epidemiológicos , Feminino , Humanos , Entrevistas como Assunto , Masculino , Rememoração Mental , Pessoa de Meia-Idade , Inquéritos Nutricionais , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: Focal spasticity of the gastrocnemius-soleus muscles causes equinus gait in children with cerebral palsy (CP). Botulinum toxin type A (BTX-A), a neuromuscular blocking agent, reduces muscle tone/overactivity in dystonia, stroke, and CP. OBJECTIVE: A prospective, open-label, multicenter clinical trial evaluated the long-term safety and efficacy of repeated intramuscular injections of BTX-A on equinus gait in CP children. METHODS: Nine centers enrolled 207 children. BTX-A injections (4 U/Kg) were given approximately every 3 months (maximum dose 200 U per treatment). Outcome measures included a Physician Rating Scale of gait, ankle range of motion measurements, and the incidence and profile of adverse events. RESULTS: One hundred fifty-five (75%) of 207 children completed at least 1 year with a total of 302 patient years of BTX-A treatment. The mean duration of BTX-A exposure was 1.46 years per patient. Dynamic gait pattern on the Physician Rating Scale improved in 46% of patients (86/185) at first follow-up. The response was maintained in 41% to 58% of patients for 2 years. Both gait pattern and ankle position improved at every visit. The most common treatment-related adverse events included increased stumbling, leg cramps, leg weakness, and calf atrophy in 1% to 11% of patients. No treatment-related serious adverse events were reported. Only 6% (7/117) of patients with pre- and postantibody samples had both detectable antibodies and a subsequent treatment failure. CONCLUSION: BTX-A proved both safe and effective in the chronic management of focal muscle spasticity in children with equinus gait.
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Toxinas Botulínicas Tipo A/uso terapêutico , Paralisia Cerebral/complicações , Pé Equino/terapia , Fármacos Neuromusculares/uso terapêutico , Bloqueio Neuromuscular/métodos , Adolescente , Pé Equino/etiologia , Feminino , Marcha , Humanos , Masculino , Estudos ProspectivosRESUMO
Turner syndrome (TS) is associated with multiple skeletal abnormalities. However, the prevalence of scoliosis in children with TS has not been reported in the orthopaedic literature. The purpose of this study was to determine the prevalence and characteristics of scoliosis in these patients. The authors performed a retrospective study of 43 patients with TS and found 5 children with a curve >10 degrees. The prevalence of scoliosis in this TS population, 11.6%, was significantly greater than the reported prevalence of idiopathic scoliosis in normal girls, 2.4%. The mean age of onset was 9 years 11 months. All curves were >34 degrees, with curves consisting of a right thoracic or S-shaped (larger lumbar segment) pattern. At the time of scoliosis presentation, two patients were not receiving growth hormone therapy. The results of this study suggest that children with TS need to be examined and closely monitored for progression of scoliosis by orthopaedists. Although curve progression can occur during growth acceleration, a direct causal association with growth hormone has not been established.
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Escoliose/epidemiologia , Síndrome de Turner/complicações , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Prevalência , Estudos RetrospectivosRESUMO
Recent models of the kinesin mechanochemical cycle provide some conflicting information on how the neck linker contributes to movement. Some spectroscopic approaches suggest a nucleotide-induced order-to-disorder transition in the neck linker. However, cryoelectron microscopic imaging suggests instead that nucleotide alters the orientation of the neck linker when docked on the microtubule surface. Furthermore, since these studies utilized transition state or non-hydrolyzable nucleotide analogs, it is not clear at what point in the ATPase cycle this reorientation of the neck linker occurs. We have addressed this issue by developing a strategy to examine the effect of nucleotide on the orientation of the neck linker based on the technique of fluorescence resonance energy transfer. Transient kinetic studies utilizing this approach support a model in which ATP binding leads to two sequential isomerizations, the second of which reorients the neck linker in relation to the microtubule surface.
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Trifosfato de Adenosina/metabolismo , Cinesinas/metabolismo , Microtúbulos/metabolismo , Proteínas Motores Moleculares/metabolismo , Tubulina (Proteína)/metabolismo , Compostos de Dansil , Dimerização , Transferência de Energia , Cinesinas/ultraestrutura , Microtúbulos/ultraestrutura , Modelos Moleculares , Modelos Teóricos , Proteínas Motores Moleculares/ultraestrutura , Conformação Proteica , Espectrometria de Fluorescência , Triptofano , Tubulina (Proteína)/ultraestruturaRESUMO
Modulation of glutathione has been proposed as a mechanism to alter the efficacy and toxicity of chemotherapeutic agents. We investigated in vitro cytoenhancement of chemotherapy toxicity by reducing cellular glutathione levels with L-buthionine-[S,R]-sulfoximine (BSO), and chemoprotection with small molecular weight sulfur-containing agents that mimic or replace glutathione. Cytotoxicity, caspase-2 enzymatic activity, and in situ DNA staining for apoptosis were assessed in cultured human small cell lung carcinoma cells and fibroblasts. BSO treatment reduced the half-maximal cytotoxic dose of the alkylating chemotherapeutics melphalan, carboplatin, and cisplatin, and increased the total magnitude of cell death. Melphalan was more sensitive than carboplatin or cisplatin to BSO. The chemoprotective agents sodium thiosulfate, N-acetylcysteine, and glutathione ethyl ester reduced the cytotoxicity of all three alkylating chemotherapeutics regardless of BSO treatment, but D-methionine was effective only against the platinum agents. N-Acetylcysteine was the most effective protectant tested. Chemoprotection against melphalan toxicity was maximally effective only if administered concurrent with chemotherapy, whereas chemoprotection for the platinum agents remained effective if delayed 4 h after chemotherapy. BSO enhancement and N-acetylcysteine chemoprotection for melphalan toxicity occurred at least partially through an apoptotic mechanism. Modulation of glutathione levels will be valuable in the clinical setting if chemotherapy and chemoprotectant can be physically and/or temporally separated. Cytoenhancement and chemoprotection may be particularly useful in the central nervous system where the blood-brain barrier of the cerebral vasculature creates two compartments, for cytoenhancement in brain tumors and systemic chemoprotection.
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Alquilantes/farmacologia , Apoptose , Butionina Sulfoximina/farmacologia , Tiossulfatos/farmacologia , Acetilcisteína/farmacologia , Antimetabólitos Antineoplásicos/farmacologia , Carboplatina/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Citoproteção , Interações Medicamentosas , Humanos , Peso Molecular , Substâncias Protetoras/farmacologia , Fatores de Tempo , Células Tumorais CultivadasRESUMO
BACKGROUND: High-dose cyclophosphamide has been proposed as an alternative immunosuppressive agent for treatment of severe aplastic anaemia, with a response rate similar to that with regimens containing antithymocyte globulin (ATG) but neither relapse nor clonal haematological complications. We undertook a phase III, prospective, randomised trial to compare response rates to immunosuppression with either high-dose cyclophosphamide plus cyclosporin or conventional immunosuppression with ATG plus cyclosporin in previously untreated patients. METHODS: Between June, 1997, and March, 2000, 31 patients were enrolled. 15 were assigned cyclophosphamide (1 h intravenous infusion of 50 mg/kg daily for 4 days) and 16 were assigned ATG (40 mg/kg daily for 4 days); both groups received cyclosporin, initially at 12 mg/kg daily with adjustment to maintain concentrations at 200-400 microg/L, for 6 months. The primary endpoint was haematological response (no longer meeting criteria for severe aplastic anaemia). The trial was terminated prematurely after three early deaths in the cyclophosphamide group. Analyses were by intention to treat. FINDINGS: Median follow-up was 21.9 months (range 1-33). There was excess morbidity in the cyclophosphamide group (invasive fungal infections, four cyclophosphamide vs no ATG patients; p=0.043) as well as excess early mortality (three deaths within the first 3 months cyclophosphamide vs no ATG patients; p=0.101). There was no significant difference at 6 months after treatment in the overall response rates among evaluable patients (six of 13 [46%] cyclophosphamide vs nine of 12 [75%] ATG). INTERPRETATION: A longer period of observation will be necessary to assess the secondary endpoints of relapse and late clonal complications as well as disease-free and overall survival. However, cyclophosphamide seems a dangerous choice for treatment of this disorder, given the good results achievable with standard therapy.