Exercise training restores the endothelial progenitor cells number and function in hypertension: implications for angiogenesis.

OBJECTIVES: Aerobic exercise training has been established as an important nonpharmacological treatment for hypertension. We investigated whether the number and function of endothelial progenitor cells (EPCs) are restored after exercise training, potentially contributing to neovascularization in hypertension. METHODS: Twelve-week-old male spontaneously hypertensive rats (SHRs, n  =  14) and Wistar-Kyoto (WKY, n  =  14) rats were assigned to four groups: SHR; trained SHR (SHR-T); WKY; and trained WKY. Exercise training consisted of 10 weeks of swimming. EPC number and function, as well as the vascular endothelial growth factor (VEGF), nitrotyrosine and nitrite concentration in peripheral blood were quantified by fluorescence-activated cell sorter analysis (CD34+/Flk1+ cells), colony-forming unit assay, ELISA and nitric oxide (NO) analyzer, respectively. Soleus capillary/fiber ratio and protein expression of VEGF and endothelial NO synthase (eNOS) by western blot were assessed. RESULTS: Exercise training was effective in reducing blood pressure in SHR-T accompanied by resting bradycardia, an increase in exercise tolerance, peak oxygen uptake (VO2) and citrate synthase activity. In response to hypertension, the amount of peripheral blood-EPC and number of colonies were decreased in comparison with control levels. In contrast, exercise training normalized the EPC levels and function in SHR-T accompanied by an increase in VEGF and NO levels. In addition, oxidative stress levels were normalized in SHR-T. Similar results were found in the number and function of bone marrow EPC. Exercise training repaired the peripheral capillary rarefaction in hypertension by a signaling pathway VEGF/eNOS-dependent in SHR-T. Moreover, improvement in EPC was significantly related to angiogenesis. CONCLUSION: Our data show that exercise training repairs the impairment of EPC in hypertension, which could be associated with peripheral revascularization, suggesting a mechanism for its potential therapeutic application in vascular diseases.

Hereditary hemochromatosis: mutations in genes involved in iron homeostasis in Brazilian patients.

BACKGROUND: p.C282Y mutation and rare variants in the HFE gene have been associated with hereditary hemochromatosis (HH). HH is also caused by mutations in other genes, such as the hemojuvelin (HJV), hepcidin (HAMP), transferrin receptor 2 (TFR2) and ferroportin (SLC40A1). The low rate homozygous p.C282Y mutation in Brazil is suggestive that mutations in non-HFE genes may be linked to HH phenotype. AIM: To screen exon-by-exon DNA sequences of HFE, HJV, HAMP, TFR2 and SLC40A1 genes to characterize the molecular basis of HH in a sample of the Brazilian population. MATERIALS AND METHODS: Fifty-one patients with primary iron overload (transferrin saturation ≥50% in females and ≥60% in males) were selected. Subsequent bidirectional DNA sequencing of HFE, HJV, HAMP, TFR2 and SLC40A1 exons was performed. RESULTS: Thirty-seven (72.5%) out of the 51 patients presented at least one HFE mutation. The most frequent genotype associated with HH was the homozygous p.C282Y mutation (n=11, 21.6%). In addition, heterozygous HFE p.S65C mutation was found in combination with p.H63D in two patients and homozygous HFE p.H63D was found in two patients as well. Sequencing in the HJV and HAMP genes revealed HJV p.E302K, HJV p.A310G, HJV p.G320V and HAMP p.R59G alterations. Molecular and clinical diagnosis of juvenile hemochromatosis (homozygous form for the HJV p.G320V) was described for the first time in Brazil. Three TFR2 polymorphisms (p.A75V, p.A617A and p.R752H) and six SLC40A1 polymorphisms (rs13008848, rs11568351, rs11568345, rs11568344, rs2304704, rs11568346) and the novel mutation SLC40A1 p.G204S were also found. CONCLUSIONS: The HFE p.C282Y in homozygosity or in heterozygosity with p.H63D was the most frequent mutation associated with HH in this sample. The HJV p.E302K and HAMP p.R59G variants, and the novel SLC40A1 p.G204S mutation may also be linked to primary iron overload but their role in the pathophysiology of HH remain to be elucidated.

Hemojuvelin and hepcidin genes sequencing in Brazilian patients with primary iron overload.

BACKGROUND: most hereditary hemochromatosis (HH) patients are homozygous for the p.C282Y mutation in the HFE gene. Some studies reported that HH phenotypic expression could be modulated by genetic factors such as HJV and HAMP gene mutations. AIMS: the aims of this study were to identify HJV and HAMP mutations and to analyze their impact on HH phenotype in non-p.C282Y homozygous individuals. METHODS: Twenty-four Brazilian patients with primary iron overload and non-p.C282Y homozygous genotype (transferrin saturation >50% in women and >60% in men and absence of secondary causes) were selected. Subsequent bidirectional sequencing of the HJV and HAMP exons was performed. RESULTS: sequencing revealed a substitution in heterozygosis, c.929C > G, which corresponds to p.A310G polymorphism in HJV exon 4 (rs7540883). In the same gene, in another individual, an IVS1-36C > G intronic variant was detected in heterozygosis. In the HAMP gene, an IVS3 + 42G > A intronic variant was identified. There were six (25.0%) patients carrying a heterozygous genotype for the HFE p.C282Y and nine (37.5%) patients carrying a heterozygous genotype for the HFE p.H63D. CONCLUSION: HJV p.A310G polymorphism and two intronic variants were found, but none of these alterations were associated with digenic inheritance with the HFE gene. Our data indicate that HJV and HAMP functional mutations are not frequent in these patients.

HFE gene mutations in patients with primary iron overload: is there a significant improvement in molecular diagnosis yield with HFE sequencing?

Rare HFE variants have been shown to be associated with hereditary hemochromatosis (HH), an iron overload disease. The low frequency of the HFE p.C282Y mutation in HH-affected Brazilian patients may suggest that other HFE-related mutations may also be implicated in the pathogenesis of HH in this population. The main aim was to screen for new HFE mutations in Brazilian individuals with primary iron overload and to investigate their relationship with HH. Fifty Brazilian patients with primary iron overload (transferrin saturation>50% in females and 60% in males) were selected. Subsequent bidirectional sequencing for each HFE exon was performed. The effect of HFE mutations on protein structure were analyzed by molecular dynamics simulation and free binding energy calculations. p.C282Y in homozygosis or in heterozygosis with p.H63D were the most frequent genotypic combinations associated with HH in our sample population (present in 17 individuals, 34%). Thirty-six (72.0%) out of the 50 individuals presented at least one HFE mutation. The most frequent genotype associated with HH was the homozygous p.C282Y mutation (n=11, 22.0%). One novel mutation (p.V256I) was indentified in heterozygosis with the p.H63D mutation. In silico modeling analysis of protein behavior indicated that the p.V256I mutation does not reduce the binding affinity between HFE and ß2-microglobulin (ß2M) in the same way the p.C282Y mutation does compared with the native HFE protein. In conclusion, screening of HFE through direct sequencing, as compared to p.C282Y/p.H63D genotyping, was not able to increase the molecular diagnosis yield of HH. The novel p.V256I mutation could not be implicated in the molecular basis of the HH phenotype, although its role cannot be completely excluded in HH-phenotype development. Our molecular modeling analysis can help in the analysis of novel, previously undescribed, HFE mutations.

Rat adipose tissue-derived stem cells transplantation attenuates cardiac dysfunction post infarction and biopolymers enhance cell retention.

BACKGROUND: Cardiac cell transplantation is compromised by low cell retention and poor graft viability. Here, the effects of co-injecting adipose tissue-derived stem cells (ASCs) with biopolymers on cell cardiac retention, ventricular morphometry and performance were evaluated in a rat model of myocardial infarction (MI). METHODOLOGY/PRINCIPAL FINDINGS: 99mTc-labeled ASCs (1x10(6) cells) isolated from isogenic Lewis rats were injected 24 hours post-MI using fibrin a, collagen (ASC/C), or culture medium (ASC/M) as vehicle, and cell body distribution was assessed 24 hours later by gamma-emission counting of harvested organs. ASC/F and ASC/C groups retained significantly more cells in the myocardium than ASC/M (13.8+/-2.0 and 26.8+/-2.4% vs. 4.8+/-0.7%, respectively). Then, morphometric and direct cardiac functional parameters were evaluated 4 weeks post-MI cell injection. Left ventricle (LV) perimeter and percentage of interstitial collagen in the spare myocardium were significantly attenuated in all ASC-treated groups compared to the non-treated (NT) and control groups (culture medium, fibrin, or collagen alone). Direct hemodynamic assessment under pharmacological stress showed that stroke volume (SV) and left ventricle end-diastolic pressure were preserved in ASC-treated groups regardless of the vehicle used to deliver ASCs. Stroke work (SW), a global index of cardiac function, improved in ASC/M while it normalized when biopolymers were co-injected with ASCs. A positive correlation was observed between cardiac ASCs retention and preservation of SV and improvement in SW post-MI under hemodynamic stress. CONCLUSIONS: We provided direct evidence that intramyocardial injection of ASCs mitigates the negative cardiac remodeling and preserves ventricular function post-MI in rats and these beneficial effects can be further enhanced by administering co-injection of ASCs with biopolymers.

Clinical profile of patients enroled in a cell therapy trial for severe coronary artery disease.

AIMS AND OBJECTIVES: To compare the clinical profile of patients included in a clinical trial of autologous bone marrow cells as an adjunctive therapy to coronary artery bypass grafting with that of patients undergoing routine coronary artery bypass grafting. BACKGROUND: The therapeutic potential of autologous bone marrow cells has been explored in the treatment of severe coronary artery disease. There are few data regarding the clinical and socio-economic profile of patients included in clinical trials using bone marrow cell. DESIGN: Case-control study. METHOD: Sixty-seven patients (61 SD 9) years, 82% men) with multivessel coronary artery disease were divided into two groups: patients in the bone marrow cell group (n = 34) underwent incomplete coronary artery bypass grafting + intramyocardial injection of autologous bone marrow cells (lymphomonocytic fraction -2.0 (SD 0.2 x 10(8)) cells/patient) in the ischaemic, non-revascularised myocardium, whereas patients in the coronary artery bypass grafting group (n = 33) underwent routine bypass surgery. Demographics, socio-economic status, clinical and echocardiographic data were collected. Statistical analysis included the Fisher's exact test (categorical variables) and the Student's t-test (continuous variables). RESULTS: There were no significant differences between groups regarding age, gender, BMI, heart rate, blood pressure and echo data. There was a greater prevalence of obesity (65 vs. 33%; OR = 3.7 [1.3-10.1]), of previous myocardial infarction (68 vs. 39%; OR = 3.2 [1.2-8.8]) and prior revascularisation procedures (59 vs. 24%; OR = 4.5 [1.6-12.7]) in the autologous bone marrow cells group and of smokers in the coronary artery bypass grafting group (51 vs. 23%; OR = 3.5 [1.2-10.4]). CONCLUSIONS: Patients included in this clinical trial of autologous bone marrow cells for severe coronary artery disease presented a greater prevalence of myocardial revascularisation procedures, indicating a more severe clinical presentation of the disease. Fewer smokers in this group could be attributable to life style changes after previous cardiovascular events and/or interventions. RELEVANCE TO CLINICAL PRACTICE: The knowledge of the clinical profile of patients included in cell therapy trials may help researchers in the identification of patients that may be enroled in future clinical trials of this new therapeutic strategy.

Association between ADAMTS13 polymorphisms and risk of cardiovascular events in chronic coronary disease.

INTRODUCTION: Association between ADAMTS13 levels and cardiovascular events has been described recently. However, no genetic study of ADAMTS13 in coronary patients has been described. MATERIALS AND METHODS: Based on related populations frequencies and functional studies, we tested three ADAMTS13 polymorphisms: C1342G (Q448E), C1852G (P618A) and C2699T (A900V) in a group of 560 patients enrolled in the Medical, Angioplasty, or Surgery Study II (MASS II), a randomized trial comparing treatments for patients with coronary artery disease (CAD) and preserved left ventricular function. The incidence of the 5-year end-points of death and death from cardiac causes, myocardial infarction, refractory angina requiring revascularization and cerebrovascular accident was determined for each polymorphim's allele, genotype and haplotype. Risk was assessed with the use of logistic regression and Cox proportional-hazards model and multivariable adjustment was employed for possible confounders. RESULTS: Clinical characteristics and received treatment of each genotype group were similar at baseline. In an adjusted model for cardiovascular risk variables, we were able to observe a significant association between ADAMTS13 900V variant and an increased risk of death (OR: 1,92 CI: 1,14-3,23, p=0,015) or death from cardiac cause (OR:2,67, CI: 1,59-4,49, p=0,0009). No association between events and ADAMTS13 Q448E or P618A was observed. CONCLUSIONS: This first report studying the association between ADAMTS13 genotypes and cardiovascular events provides evidence for the association between ADAMTS13 900V variant and an increased risk of death in a population with multi-vessel CAD.

Cell therapy attenuates cardiac dysfunction post myocardial infarction: effect of timing, routes of injection and a fibrin scaffold.

BACKGROUND: Cell therapy approaches for biologic cardiac repair hold great promises, although basic fundamental issues remain poorly understood. In the present study we examined the effects of timing and routes of administration of bone marrow cells (BMC) post-myocardial infarction (MI) and the efficacy of an injectable biopolymer scaffold to improve cardiac cell retention and function. METHODOLOGY/PRINCIPAL FINDINGS: (99m)Tc-labeled BMC (6 x 10(6) cells) were injected by 4 different routes in adult rats: intravenous (IV), left ventricular cavity (LV), left ventricular cavity with temporal aorta occlusion (LV(+)) to mimic coronary injection, and intramyocardial (IM). The injections were performed 1, 2, 3, or 7 days post-MI and cell retention was estimated by gamma-emission counting of the organs excised 24 hs after cell injection. IM injection improved cell retention and attenuated cardiac dysfunction, whereas IV, LV or LV* routes were somewhat inefficient (<1%). Cardiac BMC retention was not influenced by timing except for the IM injection that showed greater cell retention at 7 (16%) vs. 1, 2 or 3 (average of 7%) days post-MI. Cardiac cell retention was further improved by an injectable fibrin scaffold at day 3 post-MI (17 vs. 7%), even though morphometric and function parameters evaluated 4 weeks later displayed similar improvements. CONCLUSIONS/SIGNIFICANCE: These results show that cells injected post-MI display comparable tissue distribution profile regardless of the route of injection and that there is no time effect for cardiac cell accumulation for injections performed 1 to 3 days post-MI. As expected the IM injection is the most efficient for cardiac cell retention, it can be further improved by co-injection with a fibrin scaffold and it significantly attenuates cardiac dysfunction evaluated 4 weeks post myocardial infarction. These pharmacokinetic data obtained under similar experimental conditions are essential for further development of these novel approaches.

Intramyocardial injection of autologous bone marrow cells as an adjunctive therapy to incomplete myocardial revascularization--safety issues.

OBJECTIVES: To determine the safety of intramyocardial injection of autologous bone marrow cells in patients undergoing surgical myocardial revascularization (CABG) for severe coronary artery disease. INTRODUCTION: There is little data available regarding the safety profile of autologous bone marrow cells injected during surgical myocardial revascularization. Potential risks include arrythmias, fibrosis in the injected sites and growth of non-cardiac tissues. METHODS: Ten patients (eight men) were enrolled; they were 59+/-5 years old with limiting angina and were non-optimal candidates for complete CABG. Bone marrow cells (1.3+/-0.3x10(8)) were obtained prior to surgery, and the lymphomonocytic fraction (CD34+ =1.8+/-0.3%) was separated by density gradient centrifugation. During surgery, bone marrow cells were injected in non-grafted areas of ischemic myocardium. During the first year after surgery, the patients underwent laboratory tests, cardiac imaging, and 24-hour ECG monitoring. RESULTS: Injected segments: inferior (n=7), anterior (n=2), septal (n=1), apical (n=1), and lateral (n=1) walls. Except for a transient elevation of C-reactive protein at one month post-surgery (P=0.01), laboratory tests results were within normal ranges; neither complex arrhythmias nor structural abnormalities were detected during follow-up. There was a reduction in functional class of angina from 3.6+/-0.8 (baseline) to 1.2+/-0.4 (one year) (P<0.0001). Also, patients had a significant decrease in the ischemic score assessed by magnetic resonance, not only globally from 0.65+/-0.14 (baseline) to 0.17+/-0.05 (one year) (P=0.002), but also in the injected areas from 1.11+/-0.20 (baseline) to 0.34+/-0.13 (one year) (P=0.0009). CONCLUSIONS: Intramyocardial injection of bone marrow cells combined with CABG appears to be safe. Theoretical concerns with arrhythmias and/or structural abnormalities after cell therapy were not confirmed in this safety trial.

Transmyocardial laser revascularization plus cell therapy for refractory angina.

We report that the use of transmyocardial laser revascularization combined with intramyocardial injection is a therapeutic option for patients with severe ischemic heart disease (IHD) not amenable to conventional myocardial revascularization. Recently, cell therapy with autologous bone marrow cells (BMC) has been tested in clinical trials for severe IHD. We tested the hypothesis that TMLR combined with intramyocardial injection of BMC is safe, and may help increase the functional capacity and myocardial perfusion in patients with refractory angina. We enrolled 8 patients (7 men), 64+/-4 years old, with refractory angina, non-candidates for another procedure. TMLR (8+/-2 laser drills) was performed via a limited thoracotomy. BMC were obtained prior to surgery, and the lymphomonocytic fraction was separated by density gradient centrifugation. During surgery, 5 mL containing approximately 1.6+/-0.2 x 10(8) BMC (CD34+=1.7+/-0.4%) was delivered by multiple injections in the ischemic myocardium. We observed a reduction in the ischemic score as assessed by MRI from 1.56+/-0.09 (B) to 0.93+/-0.10 (6M) (P=0.01), as well as a reduction in functional class of angina from 3.6+/-0.2 (B) to 1.4+/-0.2 (6M) (P<0.0001). We concluded that, in this early experience, the combined strategy of TMLR plus cell therapy appeared to be safe, and may have synergistically acted to reduce myocardial ischemia, with clinically relevant improvement in functional capacity.

Intramyocardial injection of autologous bone marrow cells as an adjunctive therapy to incomplete myocardial revascularization: safety issues

OBJECTIVES: To determine the safety of intramyocardial injection of autologous bone marrow cells in patients undergoing surgical myocardial revascularization (CABG) for severe coronary artery disease. INTRODUCTION: There is little data available regarding the safety profile of autologous bone marrow cells injected during surgical myocardial revascularization. Potential risks include arrythmias, fibrosis in the injected sites and growth of non-cardiac tissues. METHODS: Ten patients (eight men) were enrolled; they were 59±5 years old with limiting angina and were non-optimal candidates for complete CABG. Bone marrow cells (1.3±0.3x10(8)) were obtained prior to surgery, and the lymphomonocytic fraction (CD34+=1.8±0.3 percent) was separated by density gradient centrifugation. During surgery, bone marrow cells were injected in non-grafted areas of ischemic myocardium. During the first year after surgery, the patients underwent laboratory tests, cardiac imaging, and 24-hour ECG monitoring. RESULTS: Injected segments: inferior (n=7), anterior (n=2), septal (n=1), apical (n=1), and lateral (n=1) walls. Except for a transient elevation of C-reactive protein at one month post-surgery (P=0.01), laboratory tests results were within normal ranges; neither complex arrhythmias nor structural abnormalities were detected during follow-up. There was a reduction in functional class of angina from 3.6±0.8 (baseline) to 1.2±0.4 (one year) (P<0.0001). Also, patients had a significant decrease in the ischemic score assessed by magnetic resonance, not only globally from 0.65±0.14 (baseline) to 0.17±0.05 (one year) (P=0.002), but also in the injected areas from 1.11±0.20 (baseline) to 0.34±0.13 (one year) (P=0.0009). CONCLUSIONS: Intramyocardial injection of bone marrow cells combined with CABG appears to be safe. Theoretical concerns with arrhythmias and/or structural abnormalities after cell therapy...

Association between platelet P2Y12 haplotype and risk of cardiovascular events in chronic coronary disease.

INTRODUCTION: A positive association was recently described between P2Y12 platelet receptor H1 and H2 haplotypes and peripheral artery disease. We tested the described P2Y12 receptor haplotypes in a group of patients with coronary artery disease. STUDY DESIGN AND METHODS: The P2Y12 platelet receptor H1 and H2 haplotypes was tested in a group of 540 patients enrolled in the Medical, Angioplasty, or Surgery Study II (MASS II), a randomized trial comparing treatments for patients with coronary artery disease (CAD) and preserved left ventricular function. After a 3-year follow-up period, the incidence of the composite end point of cardiac death, myocardial infarction, and refractory angina requiring revascularization was determined in the H1/H1, H1/H2 and H2/H2 haplotype groups. We used Student's t-test and the chi-square test to analyze the differences among groups and Kaplan-Meier method to calculate survival curves. Risk was assessed with the use of a Cox proportional-hazards model. RESULTS: The frequency of haplotypes among studied patients were 410 (75.9%) H1/H1, 119 (22.0%) H1/H2 and 11 (2.1%) H2/H2. The baseline clinical characteristics, mean clinical follow-up time and received treatment of each genotype group were similar. We did not disclose any association between haplotype groups regarding the incidence of any of the studied cardiovascular end-points. CONCLUSION: This is the first report studying the association of P2Y12 platelet receptor H1 and H2 haplotype and cardiovascular events. Our findings do not provide evidence for a strong association between H1/H1 and H1/H2 haplotypes and a increased risk of cardiovascular events in a population with CAD. Future works should address the role of the H2/H2 haplotype as a genetic marker for cardiovascular events.

Cell therapy plus transmyocardial laser revascularization for refractory angina.

We describe the use of autologous bone marrow cells combined with transmyocardial laser revascularization in a 74-year-old man with refractory angina. Baseline cardiac magnetic resonance imaging revealed a markedly depressed left ventricle systolic function and an extensive area of myocardial ischemia. During surgery, 11 laser shots using a CO2 Heart Laser System (PLC Medical Systems, Milford, MA) were fired and a 5-mL cell suspension containing 21.5 x 10(6) bone marrow cells/mL was delivered by multiple injections into the myocardium. At 6 months after the procedure, another cardiac magnetic resonance imaging showed an almost complete resolution of the perfusion defect and an improvement in left ventricular contractility.

Transplante de medula óssea alogênico em paciente portador de anemia aplástica com osteomielite / Bone marrow transplantation in patients with aplastic anemia with osteomyelitis

Os autores apresentam o caso de uma criança de 9 anos portadora de anemia aplástica grave, com causa desconhecida, previamente politransfundida e portadora de osteomielite. Como terapêutica básica foi escolhido o TMO alogênico. Teve boa evoluçäo após o TMO, mas no 50§ dia teve perda do enxerto e evoluiu para óbito devido a processo infeccioso após tentativa de segunda infusäo da medula do irmäo. Säo discutidos aqui os dados clínicos e clínico-patológicos com execuçäo de estudo necroscópico

Contribuiçäo ao conhecimento clínico, epidemiológico e histopatológico da doença de Hodgkin, em uma populaçäo brasileira / Contributions to the clinical, epidemiological and histopathological knowledge of the Hodgkin disease, in a Brazilian population

O conhecimento a respeito das características e do comportamento da doença de Hodgkin, no Brasil, näo está completamente estabelecido e há poucos estudos descritos na literatura internacional sobre a nossa realidade. O autor estudou 134 casos da doença de Hodgkin acima de 15 anos de idade, retrospectiva e exploratoriamente, envolvendo 76 do sexo masculino e 58 do feminino, de 1985 a 1994, atendidos em um único hospital universitário de referência, para uma regiäo de 6 milhöes de habitantes. Foram estudados os dados clínicos, laboratoriais, radiológicos, tomográficos, ultra-sonográficos, histopatológicos e evolutivos em todos os pacientes, ao diagnóstico e após o tratamento protocolar da istituiçäo. A doença de Hodgkin apresentou predomínio no sexo masculino (R=1,31); pico de incidência entre 21 e 30 anos; 2/3 dos casos abaixo dos 40 anos; e curva decrescente de incidência após os 30 anos. O tipo histológico mais freqüente foi a esclerose nodular (50,4 por cento), seguido pelos de celularidade mistra (34,6 por cento), depleçäo linfocitária (9 por cento) e predominância linfocitária (5,2 por cento). O tipo esclerose nodular-I prevaleceu sobre o tipo esclerose nodular-II (30,8 por cento e 19,6 por cento respectivamente). O tipo esclerose nodular foi singnificativamente mais freqüente nas mulheres e o tipo celularidade mista, nos homens...

Insuficiência respiratória aguda associada a estreptococcia secundária a altas doses de citosina arabinosídeo / Acute respiratory insufficiency associated with streptococcal infection secondary to high dose of cytosine arabinoside

Um quadro de insuficiência respiratória aguda tem sido descrito em pacientes submetidos a quimioterapia com Citarabina em altas doses, concomitante à detecçäo de Streptococcus sp. O quadro clínico pode ser fatal e envolve múltiplos fatores. Profilaxia com penicilina tem sido utilizada para evitar esta complicaçäo. Aqui, descrevemos a evoluçäo de um caso clínico após o uso de Citarabina altas doses com insuficiência respiratória aguda, onde foi detectado Streptococcus Viridans.