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1.
Nature ; 621(7977): 56-59, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37364766

RESUMO

Forty years ago, it was proposed that gas-phase organic chemistry in the interstellar medium can be initiated by the methyl cation CH3+ (refs. 1-3), but so far it has not been observed outside the Solar System4,5. Alternative routes involving processes on grain surfaces have been invoked6,7. Here we report James Webb Space Telescope observations of CH3+ in a protoplanetary disk in the Orion star-forming region. We find that gas-phase organic chemistry is activated by ultraviolet irradiation.

2.
Rinsho Ketsueki ; 63(3): 201-205, 2022.
Artigo em Japonês | MEDLINE | ID: mdl-35387933

RESUMO

The patient is a 34-year-old HIV antibody-negative female with normal immunocompetence. The patient was referred to the hospital of the current study due to diarrhea and abdominal pain, which developed in May 2014. On conducting computed tomography (CT), remarkable wall thickening was noted in the terminal ilium over the ascending colon, suggesting a malignant tumor. However, making a definite diagnosis by lower gastrointestinal endoscopic biopsy and left hemicolectomy was not possible. The dense proliferation of plasma cell-like cells and plasmablasts was noted; CD20, CD19, CD79a, CD3, CD4, and Epstein-Barr virus-encoded miRNAs (EBER) were negative and CD138 was positive on immunostaining. Based on the aforementioned data, the patient was diagnosed with plasmablastic lymphoma (PBL). High-dose chemotherapy combined with autologous peripheral blood stem cell transplantation (PBSCT) was performed in the first remission period after the completion of four cycles of hyper CVAD/MTX-AraC alternating therapy. Remission was confirmed by FDG-PET/CT 3 months after autologous PBSCT. No signs of recurrence have been observed in 6 years after the transplantation. Although no standard treatment for PBL has been established, autologous peripheral blood stem cell transplantation combined with high-dose chemotherapy during the first remission period may be a beneficial treatment option.


Assuntos
Infecções por Vírus Epstein-Barr , Infecções por HIV , Transplante de Células-Tronco de Sangue Periférico , Linfoma Plasmablástico , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica , Feminino , Infecções por HIV/complicações , Herpesvirus Humano 4 , Humanos , Linfoma Plasmablástico/diagnóstico , Linfoma Plasmablástico/terapia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Transplante Autólogo
3.
Rinsho Ketsueki ; 62(11): 1604-1608, 2021.
Artigo em Japonês | MEDLINE | ID: mdl-34866083

RESUMO

The novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is rapidly spreading across the world. We encountered two patients with COVID-19 who underwent treatment for acute leukemia at initial diagnosis. Both the patients received conventional induction therapy without the exacerbation of COVID-19. Although the impact of SARS-CoV-2 on the treatment of leukemia is unclear, our treatment experience suggests that there is no major contraindication to standard chemotherapy for acute leukemia in patients with COVID-19. As COVID-19 continues to be a threat worldwide, further evaluations of large cohorts are needed for future treatment decisions for acute leukemia with COVID-19.


Assuntos
COVID-19 , Leucemia , Humanos , Reação em Cadeia da Polimerase , SARS-CoV-2
6.
Rinsho Ketsueki ; 58(4): 323-325, 2017.
Artigo em Japonês | MEDLINE | ID: mdl-28484160

RESUMO

A 44-year-old woman had repeated bacterial infections because of hypoplastic myelodysplastic syndrome; therefore, she underwent allogeneic hematopoietic cell transplantation. Broad spectrum antibiotics were administered because she had bacterial infection and pneumonia 2 weeks before undergoing transplantation. On day19 after transplantation, she suddenly presented with hemoptysis. Stenotrophomonas maltophilia was considered to be the cause of hemorrhagic pneumonia, which required ventilation support, massive transfusion, and catecholamine administration. However, she died 8 h after the onset of hemoptysis. Severe S. maltophilia infections may occur in patients with immunocompromised conditions such as those after allogeneic hematopoietic cell transplantation.


Assuntos
Transplante de Medula Óssea/efeitos adversos , Infecções por Bactérias Gram-Negativas/microbiologia , Síndromes Mielodisplásicas/terapia , Pneumonia Bacteriana/microbiologia , Stenotrophomonas maltophilia/isolamento & purificação , Adulto , Evolução Fatal , Feminino , Infecções por Bactérias Gram-Negativas/terapia , Humanos , Pneumonia Bacteriana/terapia
7.
Ann Hematol ; 94(11): 1885-90, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26251157

RESUMO

Differential diagnosis between transthyretin (TTR) and immunoglobulin light-chain (AL) cardiac amyloidoses is essential due to significantly different prognoses and therapeutic options. Therefore, clinical characteristics of patients with biopsy-proven cardiac amyloidosis were investigated to differentiate TTR from AL amyloidosis. From September 2006 to May 2014, 46 patients were confirmed to have cardiac amyloidosis (TTR, n = 28; AL, n = 18) in our institute. The median age of patients with TTR amyloidosis was 78 years (range 61-90) with 27 (96 %) males, while that of patients with AL amyloidosis was 66 (range 52-76) with 12 (67 %) males. There were no statistically significant differences in echocardiographic findings regarding left ventricular (LV) systolic function or diastolic dysfunction between the two groups. Interestingly, serum brain natriuretic peptide (BNP) levels in patients with AL amyloidosis were significantly higher than those in TTR amyloidosis patients. In contrast, the LV wall was significantly thicker in patients with TTR amyloidosis than in those with AL amyloidosis. Therefore, the ratio of BNP to LV mass index (LVMI) at presentation in AL amyloidosis patients was significantly higher than that in TTR patients (6.7 vs 2.9, p = 0.0006). A BNP-LVMI ratio of less than 3.5 had a diagnostic sensitivity and specificity for TTR amyloidosis of 71 and 83 %, respectively. One-year overall survival was 88.7 % in the patients with TTR amyloidosis and 23.7 % in the patients with AL amyloidosis. Our analysis indicates that the BNP-LVMI ratio, as well as age and sex, may be useful parameters for distinguishing TTR from AL cardiac amyloidosis.


Assuntos
Neuropatias Amiloides Familiares/diagnóstico por imagem , Neuropatias Amiloides Familiares/patologia , Amiloidose/diagnóstico por imagem , Amiloidose/patologia , Cardiomiopatias/diagnóstico por imagem , Cardiomiopatias/patologia , Idoso , Idoso de 80 Anos ou mais , Diagnóstico Diferencial , Ecocardiografia , Feminino , Humanos , Cadeias Leves de Imunoglobulina/efeitos adversos , Amiloidose de Cadeia Leve de Imunoglobulina , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
8.
Rinsho Ketsueki ; 56(12): 2452-5, 2015 Dec.
Artigo em Japonês | MEDLINE | ID: mdl-26725354

RESUMO

A 45-year-old man was diagnosed with t(8;21) positive acute myelogenous leukemia and failed to achieve complete remission (CR) after the first induction chemotherapy. He was then treated with high-dose cytarabine and achieved CR. Molecular relapse was detected during post-remission therapy and he underwent myeloablative bone marrow transplantation from his HLA-matched sibling donor. One year after transplantation, he developed an intractable anal fistula during treatment of chronic GVHD. Colonoscopy showed longitudinal ulcers and cobblestone appearance, and histopathological examination revealed non-caseating epithelioid granuloma. According to these findings, he was diagnosed with Crohn's-like chronic gastrointestinal inflammatory disease. He was treated with enteral nutrition, mesalazine and dose re-escalation of cyclosporine, but these therapies were not effective. Therefore, we decided to treat him with infliximab. After starting treatment with infliximab, his abdominal symptoms and the anal fistula showed prompt improvement. There are few reports regarding the efficacy of infliximab for gastrointestinal chronic GVHD. Our experience suggests that infliximab could be useful for the treatment of Crohn's-like gastrointestinal inflammatory disease.


Assuntos
Transplante de Medula Óssea , Gastroenteropatias/patologia , Gastroenteropatias/terapia , Doença Enxerto-Hospedeiro/terapia , Infliximab/uso terapêutico , Leucemia Mieloide Aguda/terapia , Citarabina/uso terapêutico , Gastroenteropatias/diagnóstico , Doença Enxerto-Hospedeiro/diagnóstico , Humanos , Leucemia Mieloide Aguda/diagnóstico , Masculino , Pessoa de Meia-Idade , Transplante Homólogo
9.
Rinsho Ketsueki ; 56(7): 889-94, 2015 Jul.
Artigo em Japonês | MEDLINE | ID: mdl-26251154

RESUMO

A 64-year-old woman underwent reduced-intensity conditioning cord blood transplantation (RIC-CBT) for refractory acute myeloid leukemia (AML). A 6/6 antigen-level HLA-identical cord blood from a male infant was transfused. After successful engraftment with complete donor chimerism, the patient developed mixed chimera (XX 8.8%) on day 82. Tapering of tacrolimus was started on day 96. Bone marrow chimerism analysis showed a decreasing recipient cell population (XX 2.2%) on day 117 and tacrolimus was discontinued with no clinical signs of GVHD on day 123. However, pancytopenia with agranulocytosis was detected on day 138. She was diagnosed as having secondary graft failure associated with Coombs-positive immune hemolytic anemia and immune thrombocytopenia (ITP). At the same time, the percentage of recipient T cell chimerism in peripheral blood was about 50% and the B cell population showed lambda light chain restriction. On day 180, she received a second RIC-CBT due to lack of improvement of agranulocytosis. A single dose of rituximab was administered on day - 11 before the second CBT to eliminate the activated B cells. Prompt neutrophil engraftment was achieved and both hemolytic anemia and ITP also showed resolution. She is currently well (30 months after the second CBT), showing normal blood cell counts and complete second donor chimerism of marrow cells.


Assuntos
Anemia Hemolítica/imunologia , Artrite Reumatoide/imunologia , Transplante de Células-Tronco Hematopoéticas , Leucemia Mieloide Aguda/terapia , Trombocitopenia/imunologia , Anemia Hemolítica/complicações , Artrite Reumatoide/complicações , Transplante de Células-Tronco de Sangue do Cordão Umbilical , Feminino , Sangue Fetal/transplante , Humanos , Leucemia Mieloide Aguda/complicações , Masculino , Pessoa de Meia-Idade , Indução de Remissão , Trombocitopenia/complicações , Falha de Tratamento
10.
Rinsho Ketsueki ; 56(12): 2472-6, 2015 Dec.
Artigo em Japonês | MEDLINE | ID: mdl-26725358

RESUMO

A 66-year-old man showed central nervous system (CNS) and epididymis involvement after concurrent chemoradiotherapy for extranodal natural killer/T-cell lymphoma, nasal type (ENKL). The patient experienced continuous nasal obstruction. CT revealed a mass in the nasal cavity and paranasal sinuses. Biopsy of the nasal cavity mass showed it to be ENKL. Based on bone marrow biopsy and 18F-FDG PET/CT findings, the clinical stage was suspected to be IIE. The sites involved were the nasal cavity, paranasal sinuses, and cervical lymph nodes. We performed concurrent chemoradiotherapy consisting of a 67% dose of DeVIC and involved field radiation therapy towards his head and neck. Head and neck CT confirmed a therapeutic response. After receiving concurrent chemoradiotherapy, the patient complained of perineal discomfort. Ultrasonography revealed swelling of the left epididymis. Left epididymis biopsy showed ENKL involvement and lumbar puncture revealed CNS involvement. The findings of this case suggest that evaluation of CNS involvement might be an essential part of the initial workup for some ENKL patients.


Assuntos
Neoplasias do Sistema Nervoso Central/patologia , Epididimo/patologia , Linfoma Extranodal de Células T-NK/tratamento farmacológico , Neoplasias Nasais/tratamento farmacológico , Idoso , Neoplasias do Sistema Nervoso Central/terapia , Quimiorradioterapia/métodos , Epididimo/efeitos dos fármacos , Humanos , Linfoma Extranodal de Células T-NK/complicações , Linfoma Extranodal de Células T-NK/patologia , Masculino , Invasividade Neoplásica , Neoplasias Nasais/complicações , Neoplasias Nasais/diagnóstico , Neoplasias Nasais/patologia
11.
Chem Senses ; 39(4): 313-22, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24474216

RESUMO

One of the most important themes in the development of foods and drinks is the accurate evaluation of taste properties. In general, a sensory evaluation system is frequently used for evaluating food and drink. This method, which is dependent on human senses, is highly sensitive but is influenced by the eating experience and food palatability of individuals, leading to subjective results. Therefore, a more effective method for objectively estimating taste properties is required. Here we show that salivary hemodynamic signals, as measured by near-infrared spectroscopy, are a useful objective indicator for evaluating sour taste stimulus. In addition, the hemodynamic responses of the parotid gland are closely correlated to the salivary secretion volume of the parotid gland in response to basic taste stimuli and respond to stimuli independently of the hedonic aspect. Moreover, we examined the hemodynamic responses to complex taste stimuli in food-based solutions and demonstrated for the first time that the complicated phenomenon of the "masking effect," which decreases taste intensity despite the additional taste components, can be successfully detected by near-infrared spectroscopy. In summary, this study is the first to demonstrate near-infrared spectroscopy as a novel tool for objectively evaluating complex sour taste properties in foods and drinks.


Assuntos
Espectroscopia de Luz Próxima ao Infravermelho , Paladar/fisiologia , Ácido Acético/farmacologia , Adulto , Aminoácidos/química , Feminino , Hemodinâmica/efeitos dos fármacos , Humanos , Masculino , Reconhecimento Psicológico , Glândulas Salivares/efeitos dos fármacos , Glândulas Salivares/metabolismo , Glândulas Salivares/fisiologia , Paladar/efeitos dos fármacos , Limiar Gustativo
12.
J Infect Chemother ; 20(4): 282-4, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24485325

RESUMO

The benefit of endotoxin absorption therapy (direct hemoperfusion with polymyxin B-immobilized fiber: PMX-DHP) for severe septic patients is still controversial. There are limited data on the clinical experience and efficacy of PMX-DHP for septic patients with hematological disorders. At our institution, 16 patients with hematological diseases underwent PMX-DHP therapy for gram-negative septic shock from February 2006 to March 2012. Most of the patients had severe neutropenia (median neutrophil counts: 7/µL) due to intensive chemotherapy for their hematological diseases. After the PMX-DHP therapy, six patients recovered from the shock status (favorable group) and ten died of the sepsis (unfavorable group). We analyzed the differences between the two groups based on clinical characteristics just before PMX-DHP therapy. Regarding sequential organ failure assessment (SOFA) score, which is a scoring system to determine the degree of organ dysfunction, all patients in the favorable group scored less than 11. The sensitivity and specificity of SOFA score less than 11 for the therapeutic efficacy were 100% and 80%, respectively. Our results suggest that septic patients with hematological diseases may not be a candidate for PMX-DHP therapy when they have already developed serious organ dysfunction.


Assuntos
Doenças Hematológicas/microbiologia , Hemoperfusão/instrumentação , Polimixina B , Sepse/sangue , Sepse/terapia , Adulto , Idoso , Feminino , Hemoperfusão/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Poliestirenos
13.
Rinsho Ketsueki ; 55(4): 450-5, 2014 04.
Artigo em Japonês | MEDLINE | ID: mdl-24850457

RESUMO

Cardiac involvement is by far the most relevant factor impacting poor outcomes of patients with systemic light-chain (AL) amyloidosis. Median survival of patients with symptomatic cardiac AL amyloidosis is less than 6 months. Approximately two-thirds of these patients die suddenly due to ventricular arrhythmias and electromechanical dissociation. We report a 56-year-old female with very severe cardiac AL amyloidosis (NT-proBNP 13,355 ng/l, troponin T 0.16 µg/l, and systolic blood pressure 100 mmHg), who was successfully treated with diuretics and an implantable cardioverter-defibrillator (ICD) and has survived for more than 4 years, to date. During the 4-year period after receiving the ICD, she experienced several episodes of sustained ventricular tachycardia and ventricular fibrillation, all successfully terminated by anti-tachycardia pacing or electrical shock. The benefit of ICD for cardiac AL amyloidosis is unclear since there have been only a few reports of successful use of this therapy for patients with cardiac AL amyloidosis. Recently, new treatment options for AL amyloidosis, such as bortezomib and lenalidomide, have shown high response rates and improved outcomes. It is important to identify those cardiac amyloidosis patients who might be more likely to benefit from ICD implantation.


Assuntos
Amiloidose/etiologia , Amiloidose/terapia , Cardiomiopatias/etiologia , Cardiomiopatias/terapia , Morte Súbita Cardíaca/prevenção & controle , Desfibriladores Implantáveis , Mieloma Múltiplo/complicações , Taquicardia Ventricular/etiologia , Taquicardia Ventricular/terapia , Feminino , Humanos , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Fatores de Tempo , Resultado do Tratamento
14.
Science ; 383(6686): 988-992, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38422128

RESUMO

Most low-mass stars form in stellar clusters that also contain massive stars, which are sources of far-ultraviolet (FUV) radiation. Theoretical models predict that this FUV radiation produces photodissociation regions (PDRs) on the surfaces of protoplanetary disks around low-mass stars, which affects planet formation within the disks. We report James Webb Space Telescope and Atacama Large Millimeter Array observations of a FUV-irradiated protoplanetary disk in the Orion Nebula. Emission lines are detected from the PDR; modeling their kinematics and excitation allowed us to constrain the physical conditions within the gas. We quantified the mass-loss rate induced by the FUV irradiation and found that it is sufficient to remove gas from the disk in less than a million years. This is rapid enough to affect giant planet formation in the disk.

15.
Kansenshogaku Zasshi ; 87(1): 49-52, 2013 Jan.
Artigo em Japonês | MEDLINE | ID: mdl-23484379

RESUMO

A 58-year-old male developed epigastric discomfort and high fever in 2010. Complete blood count showed leukocytosis and a small number of atypical lymphocytes. Gastric endoscopy revealed multiple gastroduodenal erosions and ulcers. Biopsy specimens were obtained and pathological examination demonstrated cytomegalic inclusion bodies. Cytomegalovirus (CMV) IgM antibody was positive and CMV DNA was detected with PCR in his blood, leading to the diagnosis of CMV gastroduodenitis. He was treated with intravenous ganciclovir and his symptoms resolved rapidly. It is recognized that CMV gastroduodenitis is extremely rare in immunocompetent hosts but sometimes shows a severe clinical course in elderly patients. The results from our present patient suggest that we should consider CMV infection in the differential diagnosis of multiple gastroduodenal erosions and ulcers. Our data also suggested that anti-CMV medications could be important treatment options for CMV gastroduodenitis, especially in elderly patients.


Assuntos
Infecções por Citomegalovirus/tratamento farmacológico , Duodenite/tratamento farmacológico , Ganciclovir/uso terapêutico , Gastrite/tratamento farmacológico , Anticorpos Antivirais/imunologia , Infecções por Citomegalovirus/diagnóstico , Infecções por Citomegalovirus/imunologia , Duodenite/virologia , Gastrite/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
16.
Rinsho Ketsueki ; 54(2): 219-23, 2013 Feb.
Artigo em Japonês | MEDLINE | ID: mdl-23470831

RESUMO

A 46-year-old woman was urgently admitted to our hospital due to acute renal failure, liver dysfunction, disseminated intravascular coagulation, shock status, and impaired consciousness. About 1 day prior to admission, she developed a high-grade fever, bilateral lower leg pain, and multiple small papules. She was diagnosed with streptococcal toxic shock syndrome (STSS) caused by Streptococcus dysgalactiae subsp. equisimilis (SDSE) associated with acute myeloid leukemia. The emm gene type of the isolated SDSE was shown to be stG2078. Her invasive streptococcal infection resolved with immediate administration of meropenem and continuous hemodiafiltration. However, she died of septic shock caused by multidrug-resistant Pseudomonas aeruginosa one month after admission. Recently, epidemiological studies have shown increasing numbers of invasive SDSE infections, including STSS and necrotizing fasciitis, often among immunocompromised patients. This suggests that hematologists as well as primary care doctors need to be aware of the possibility of the invasive infections caused by SDSE. An influenza-like illness consisting of a fever, lower extremity pain, and diarrhea are common initial symptoms in STSS patients. Awareness of these prodromal symptoms could lead to the early diagnosis of the illness and prompt initiation of antibiotic treatment.


Assuntos
Antibacterianos/uso terapêutico , Leucemia Mieloide Aguda/tratamento farmacológico , Choque Séptico/microbiologia , Infecções Estreptocócicas/tratamento farmacológico , Streptococcus/isolamento & purificação , Evolução Fatal , Feminino , Humanos , Leucemia Mieloide Aguda/complicações , Leucemia Mieloide Aguda/diagnóstico , Pessoa de Meia-Idade , Choque Séptico/diagnóstico , Infecções Estreptocócicas/complicações , Infecções Estreptocócicas/diagnóstico
17.
Kansenshogaku Zasshi ; 86(3): 300-5, 2012 May.
Artigo em Japonês | MEDLINE | ID: mdl-22746054

RESUMO

A 63-year-old man had been treated with intensive chemotherapy for acute myeloid leukemia. On the 49th hospital day, he had febrile neutropenia after the second course of induction chemotherapy. On the 53 rd hospital day, he presented with hemoptysis and developed acute respiratory failure requiring ventilator support within several hours. On the 54th hospital day, the patient died with hemorrhagic respiratory infection. Stenotrophomonas maltophilia was detected in bacterial cultures of his blood, bronchoalveolar lavage, and sputum. To our knowledge, nine cases of fatal hemorrhagic pneumonia caused by S. maltophilia have been reported in the literature. All the patients had hematological neoplasms and were severely neutropenic after one or two intensive chemotherapy regimens. They died shortly (within 3 days) after the onset of the hemorrhagic pneumonia. Management of the infection caused by S. maltophilia is hampered by high-level intrinsic resistance to multiple antibiotics and the increasing occurrence of acquired resistance to co-trimoxazole and fluoroquinolones. It would be important to keep in mind that hemorrhagic respiratory infection caused by S. maltophilia may lead to a fulminant and lethal course in severely neutropenic patients with hematological neoplasms and to recognize which antibiotic agents are more sensitive to S. maltophilia in each institution.


Assuntos
Infecções por Bactérias Gram-Negativas/complicações , Hemorragia/etiologia , Leucemia Mieloide Aguda/tratamento farmacológico , Pneumopatias/etiologia , Pneumonia Bacteriana/complicações , Stenotrophomonas maltophilia , Antibióticos Antineoplásicos/administração & dosagem , Antimetabólitos Antineoplásicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Citarabina/administração & dosagem , Daunorrubicina/administração & dosagem , Evolução Fatal , Humanos , Leucemia Mieloide Aguda/complicações , Masculino , Pessoa de Meia-Idade
18.
Mod Rheumatol Case Rep ; 6(2): 273-277, 2022 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-35365826

RESUMO

We had two cases of trisomy 8-positive myelodysplastic syndrome (MDS) with incomplete Behçet's disease (BD) in which the remissions of both diseases were maintained by allogeneic stem cell transplantation (allo-SCT). Among MDS with BD patients, sometimes it is difficult to control the symptoms of BD with standard therapies such as corticosteroids and tumor necrosis factor (TNF) inhibitors. Although there should be careful consideration regarding indications for transplantation, our two cases, in which refractory BD was completely controlled by allo-SCT, suggest that allo-SCT can be one of the treatment options for higher-risk MDS with BD patients.


Assuntos
Síndrome de Behçet , Transplante de Células-Tronco Hematopoéticas , Síndromes Mielodisplásicas , Síndrome de Behçet/complicações , Síndrome de Behçet/diagnóstico , Síndrome de Behçet/terapia , Cromossomos Humanos Par 8 , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Síndromes Mielodisplásicas/complicações , Síndromes Mielodisplásicas/diagnóstico , Síndromes Mielodisplásicas/terapia , Trissomia
19.
Nature ; 434(7036): 995-8, 2005 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-15846339

RESUMO

The birth of very massive stars is not well understood, in contrast to the formation process of low-mass stars like our Sun. It is not even clear that massive stars can form as single entities; rather, they might form through the mergers of smaller ones born in tight groups. The recent claim of the discovery of a massive protostar in M17 (a nearby giant ionized region) forming through the same mechanism as low-mass stars has therefore generated considerable interest. Here we show that this protostar has an intermediate mass of only 2.5 to 8 solar masses (M(o), contrary to the earlier claim of 20M(o) (ref. 8). The surrounding circumstellar envelope contains only 0.09M(o) and a much more extended local molecular cloud has 4-9M(o).

20.
Int J Mol Sci ; 12(6): 3432-44, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21747686

RESUMO

A mechanism for creating an enantioenrichment in the amino acids, the building blocks of the proteins, that involves global selection of one handedness by interactions between the amino acids and neutrinos from core-collapse supernovae is defined. The chiral selection involves the dependence of the interaction cross sections on the orientations of the spins of the neutrinos and the (14)N nuclei in the amino acids, or in precursor molecules, which in turn couple to the molecular chirality. It also requires an asymmetric distribution of neutrinos emitted from the supernova. The subsequent chemical evolution and galactic mixing would ultimately populate the Galaxy with the selected species. The resulting amino acids could either be the source thereof on Earth, or could have triggered the chirality that was ultimately achieved for Earth's proteinaceous amino acids.


Assuntos
Aminoácidos/química , Evolução Química , Campos Magnéticos , Nêutrons , Nitrogênio/química , Origem da Vida , Estereoisomerismo
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